JP2002504445A - Printhead improvements - Google Patents

Abstract

Abstract: A wiper blade (6) for screen printing, comprising a web of synthetic material mounted on a printhead (1) near one of its longitudinal edges, and a web of synthetic material. Extends towards the screen and has a leading angle during the printing operation, a metal reinforcement member (12) located on the other longitudinal edge of the wiper blade, and the metal reinforcement member (12) A wiper blade (6) that also functions as a wear strip and includes contacting a screen during a printing operation. Further disclosed is a printhead for a screen printer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a print head. In particular, the first aspect relates to a wiper blade (such as a wiper blade used for screen printing) and the second aspect relates to a print head (such as a print head used for screen printing).

[0002]

[Prior art]

To extrude the material to be printed through multiple openings in the printing screen, conventional screen printing presses use a squeegee blade that drags along the printing screen at an angle and is held between the screen and the wiper blade. A reservoir of the printed material, in the form of a bead, is pulled across the screen.

[0003] A co-pending application, PCT / EP97 / 05761, discloses an improved screen-printed form, wherein the printed material (
Instead of dragging the substance to be printed) onto the screen and dragging it across the screen with a squeegee blade, place the substance in a chamber that is pressed on the screen and has an open end, and the substance is placed on the screen. This material is moved towards the screen by means such as a piston that can be pressurized.

[0004] At least one elongated flexible wiper is provided, the wiper being in a direction perpendicular to the direction of movement of the device on the stencil and in the direction of movement of said substance approaching the screen. Extends in an orthogonal direction, and furthermore, the wiper is inclined inward so as to extend across the open end of the chamber, pressing the chamber against the screen and pressing the product through the screen. In doing so, the wiper is configured to function to provide a scraping action that lifts the paste off the screen and a "rotating" action of the paste.

[0005] Thus, rather than having a trailing angle as in squeegees used in conventional printing, the wipers in this new form of printing have a leading angle.

[0006] It has been proposed to form such wipers from polyester materials sold under the trade name Mylar.

[0007]

Problems to be Solved by the Invention and Means for Solving the Problems

According to a first aspect of the present invention, there is provided a wiper blade for screen printing, wherein the web of synthetic material is mounted on a printhead near one longitudinal edge thereof, and the web of synthetic material comprises a screen. And having a leading angle during the printing operation, a metal stiffener located on the other longitudinal edge of the wiper blade, the metal stiffener also functioning as a wearstrip, and A wiper blade is provided that includes contacting a screen during a printing operation.

Preferably, the thickness of the metal member is equal to or less than the thickness of the synthetic wiper blade. The width of the metal member is preferably equal to or less than the width of the synthetic wiper blade.

[0009] The metal member is 10-70% of the thickness of the synthetic wiper blade, preferably about 20%.
More preferably, it has a thickness of 10 to 40%, preferably about 23% of the width of the wiper blade. The metal member may be flush with the free edge of the synthetic wiper blade (i.e., not projecting at all) or may be up to 30 mm in width of the metal member
Percentage may extend beyond the free edge of the blade. The metal reinforced wear strip is preferably formed from stainless steel, which increases the stiffness of the composite wiper blade while still allowing the wiper blade to flex and increase the wear resistance of the wiper blade. This can achieve higher and more consistent print quality in the printing operation. Metal members are spring steel,
It can be formed from titanium or various other materials known to those skilled in the art.

In one embodiment, for example, the wiper blade is formed from polyester, the metal reinforcing strip is formed from stainless steel, and the wiper blade has a total length of 340 millimeters and attaches the wiper blade to the printhead. 22 has six slots on one edge through which a screw can be inserted.
With a width of millimeters and a thickness of 0.5 millimeters, the stainless steel blade is glued to the edge opposite the said edge, which is provided with slots for threading screws. It is fixed and has the same length as the length of the wiper blade, a width of 5 mm, a thickness of 0.1 mm, and a protrusion projecting 0.5 mm from the free edge of the wiper blade.

[0011] Yet another aspect of the present invention aims to make the screen printing process disclosed in the co-pending application more effective.

[0012] As previously mentioned, previously proposed processes use a chamber that houses a printing product therein. With the use of the chamber, the product is discharged and the amount of the product in the chamber gradually decreases. When the chamber is emptied, the empty chamber needs to be replaced with a new chamber before the printing process can continue. The used chamber is then returned to the manufacturer for replenishment (which is expensive) or discarded (
This is wasteful and can damage the environment.) In either case, the printing process must be paused to allow for chamber replacement.

To mitigate at least some of these and other problems, a second aspect of the present invention is provided.
An aspect of the invention is a printhead for a screen printer, comprising a body, a container for a printing product, and one or more filling openings operable to inject the printing product into the container. During a print operation,
In order to prevent the printing product from being discharged from each opening, each opening is provided with a printhead, which is associated with a corresponding sealing means. This aspect of the invention allows a user of the chamber to inject a printing product into the chamber to refill the chamber, thereby
Prevent the expense and waste associated with previously proposed arrangements. The arrangement according to the invention makes it possible to change printing products "on the fly", thereby avoiding interruptions in the printing process.

The present invention will be described by examples with reference to the accompanying drawings.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

First, as shown in FIGS. 1-3, the printhead 1 comprises a body 2 having a lower chamber 4 for containing a product to be printed, a plurality of end sealing blocks 5 for the chamber 4, A wiper blade 6 provided one on each side of the chamber 4, each wiper blade 6 being gripped by means of a mounting bar 7, the mounting bar 7 being provided with an opening through which a screw 8 is inserted. The screw 8 extends through a slot provided at the edge of each wiper blade 6 and is screwed into a screw hole of the main body 2.

One of the wiper blades 6 effective during the printing operation is a blade located on the trailing side of the chamber 4 when considered in the moving direction of the print head 1, and the wiper blade 6 is used during use. It should be noted that it forms a leading angle with respect to a screen (not shown in FIGS. 1 to 3) located below the print head 1.

During the printing operation, when viewed in the moving direction of the head, the blade 6 located on the leading side of the head merely seals. To press the blade against the screen, the print head is depressed. Pressure is also applied to the material to be printed in the chamber 4 to push it out of the screen. The pressure applied to this material also acts on the leading wiper blade 6, which presses it onto the screen to seal it, but on the top surface of the screen in front of the wiper blade 6, is printed. Since there is no substance, this wiper blade 6 does not exhibit a scraping action.

A printhead of the type shown in FIGS. 1-3 can be used to perform a printing operation in one of two directions, indicated by a bidirectional arrow 9 in FIG.

As shown in FIGS. 4 to 6, each wiper blade 6 is a flat strip 10 of polyester having a width of 21.5 mm, a thickness of 0.5 mm and a length of 340 mm. Is formed. One edge 1
Six slots 11 for accommodating the shaft of the screw 8 are provided in Oa. Near the other edge 10b is provided a metal strip 12 of stainless steel glued to the strip 6, which has the same length as the wiper blade 6, a width of 5 mm, a width of 0.1 mm and a width of 0.1 mm. And has a thickness of millimeters.

As shown in FIG. 6, the metal strip 12 projects beyond the adjacent edge 10 b of the polyester strip 10 by about 0.5 mm of the portion 12 a and is in the operative position as shown in FIG. The metal strip 12 is located below the polyester strip 10 so that during the printing operation, it is the metal strip 12 that contacts the screen and the polyester strip 1
Not zero.

Thus, while the metal strip 12 provides stiffness to the wiper blade 6, it still allows bending of the wiper blade 6, increases the wear resistance of the wiper blade 6, and provides uniform printing in operation. Provide quality.

As mentioned above, FIG. 7 shows a front view of a print head 30 according to the second aspect of the present invention. The print head 30 is similar in appearance to the print head detailed with reference to FIGS. 1 to 6 and has a body 32, the body 32 being hollow and forming a printing product container. The printing product is discharged from the printing product container through the printing product orifice 34.

On either side of the printing product orifice 34 is provided a pair of wiper blades 36 (only one of which is visible) secured to the body 32 by screws or other suitable means 38.

As shown in FIG. 8, the body 32 has an upper section 35, a center section 37 and a lower section 38 (alternatively, the body may have a pair of removable sections if desired. obtain). These sections are separable from each other. These three sections 35, 37, 38 form the body 32 and the printing product container in cooperation with each other.

In a preferred arrangement, a plurality of screws attaching the upper section to the central section and another plurality of screws 39 attaching the central section to the lower section 38 (see FIG. 7) provide for an upper section, a central section and a lower section of the body. The lower sections are joined together.

The O-ring seal 50 is provided between the central section and the lower section, and the diaphragm 52 is provided between the upper section and the central section. Diaphragm 52 is made of rubber or any other suitable material and has a top hat-shaped cross section.

As shown in FIG. 8, diaphragm 52 extends into the cavity formed by upper section 35. In use, it drives the diaphragm, which
Pressure is applied between the diaphragm and the upper section wall to move the printing product toward orifice 34.

The rubber has elasticity that can reduce the likelihood of the printing product being ejected from the orifice when not needed by moving the diaphragm toward its initial position when the pressure is removed. Therefore, a diaphragm made of rubber is preferable.

In this embodiment, the printing product container is formed by a plurality of inner walls of a diaphragm 52 housed in an upper section 35, a center section and a lower section 38. As shown in FIG. 7, the body 32 has one or more sealing means 40 in its front wall. In the preferred embodiment, three sealing means 40 are provided in the front wall of the printhead 30, but may be more or less, and these may be in the front wall of the printhead 30. It is not always necessary to arrange them.

Preferably, each sealing means comprises a valve assembly such as a ball valve. Alternatively, each sealing means may include a cap for closing a channel communicating with the interior of the printing product container.

As shown in FIG. 9, in a preferred embodiment, each valve assembly 40 has a channel 46 within which a ball 42 is movably retained. When the print head 30 is used, the pressure applied to the printing product container causes the ball 42 to
6 to close the passage communicating with the interior of the printhead 30.

At other times (for example, the print head is rearranged in a printing device (not shown),
When pressure is released from the printing product container), a new printing product is injected under pressure into the printhead 30 by one or more valve assemblies 40 to move the ball 42 to open the passage 46. I do.

When refilling the printhead 30, the printhead 30 can be left in the printing device or removed from the printing device. Instead,
The printhead may be in communication with a source of printing product to allow for continuous replenishment of the printing product.

[0034] Instead of a valve assembly, a simple cap or plug, or stopper, may be provided. When the cap is in place, the cap closes the channel that communicates with the printing product container, and the cap is snap-fitted to the channel or screwed to the outer or inner wall of the channel. obtain.

The plug, or plug, can be pressed into a friction fit with the wall of the channel. Alternatives to these are obvious.

This second aspect of the invention may be used in combination with the first aspect, or may be other types of printheads, such as those disclosed in the co-pending application. Understand that it may be used within. Finally, it is understood that aspects of the present invention are disclosed for illustrative purposes only, and that modifications may be made within the scope of the present invention.

[Brief description of the drawings]

FIG. 1 is a perspective view of a print head having a wiper blade according to the present invention, showing one end and one side face of the print head viewed from below.

FIG. 2 is a view of a print head having a wiper blade according to the present invention, and is an end view seen from one end of the print head.

FIG. 3 is a perspective view of a print head having a wiper blade according to the present invention, showing the other end and the other side surface of the print head from above.

FIG. 4 is a plan view of a wiper blade according to the present invention.

FIG. 5 is an enlarged sectional view taken along line VV of FIG. 4;

FIG. 6 is an enlarged view of the lower part of FIG. 5;

FIG. 7 is a front view of the print head.

FIG. 8 is a sectional view taken along line XX of FIG. 7;

FIG. 9 is a sectional view taken along line AA of FIG. 7;

[Procedural Amendment] Submission of translation of Article 34 Amendment of the Patent Cooperation Treaty

[Submission date] March 13, 2000 (2000.3.13)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Detailed description of the invention

[Correction method] Change

[Correction contents]

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a print head. In particular, the first aspect relates to a wiper blade (such as a wiper blade used for screen printing) and the second aspect relates to a print head (such as a print head used for screen printing).

[0002]

BACKGROUND OF THE INVENTION In order to extrude a substance to be printed through a plurality of openings in a printing screen, conventional screen printing presses use a squeegee blade that drags along the printing screen at a predetermined angle, and the screen and wiper blades are used. A reservoir of the substance to be printed, in the form of a bead held between them, is pulled across the screen.

[0003] A co-pending application, PCT / EP97 / 05761, discloses an improved screen-printed form, wherein the printed material (
Instead of dragging the substance to be printed) onto the screen and dragging it across the screen with a squeegee blade, place the substance in a chamber that is pressed on the screen and has an open end, and the substance is placed on the screen. This material is moved towards the screen by means such as a piston that can be pressurized.

[0004] At least one elongated flexible wiper is provided, the wiper being in a direction perpendicular to the direction of movement of the device on the stencil and in the direction of movement of said substance approaching the screen. Extends in an orthogonal direction, and furthermore, the wiper is inclined inward so as to extend across the open end of the chamber, pressing the chamber against the screen and pressing the product through the screen. In doing so, the wiper is configured to function to provide a scraping action that lifts the paste off the screen and a "rotating" action of the paste.

[0005] Thus, rather than having a trailing angle as in squeegees used in conventional printing, the wipers in this new form of printing have a leading angle.

[0006] It has been proposed to form such wipers from polyester materials sold under the trade name Mylar.

[0007]

According to a first aspect of the present invention, there is provided a print head for screen printing, comprising a chamber for a substance to be printed. The chamber has an open end; means for pushing a substance to be printed onto the screen through the open end of the chamber, and at least one wiper blade is attached to the open end of the chamber, wherein the wiper blade is A metal stiffener member comprising a web of synthetic material mounted on the printhead with a leading angle near one of its longitudinal edges, and on the other longitudinal edge of the blade, which contacts the screen during a printing operation Is installed, the wiper blade lifts the substance to be printed The metal reinforcement member is mounted to the printhead so as to pass slightly across the screen, and metal reinforcement to increase the wear resistance of the wiper blade as the blade rubs across the screen during printing operations. The member also functions as a wear strip.

The thickness of the metal member is preferably equal to or less than the thickness of the synthetic wiper blade. The width of the metal member is preferably equal to or less than the width of the synthetic wiper blade.

[0009] The metal member is 10-70% of the thickness of the synthetic wiper blade, preferably about 20%.
More preferably, it has a thickness of 10 to 40%, preferably about 23% of the width of the wiper blade. The metal member may be flush with the free edge of the synthetic wiper blade (i.e., not projecting at all) or may be up to 30 mm in width of the metal member
Percentage may extend beyond the free edge of the blade. The metal reinforced wear strip is preferably formed from stainless steel, which increases the stiffness of the composite wiper blade while still allowing the wiper blade to flex and increase the wear resistance of the wiper blade. This can achieve higher and more consistent print quality in the printing operation. Metal members are spring steel,
It can be formed from titanium or various other materials known to those skilled in the art.

In one embodiment, for example, the wiper blade is formed from polyester, the metal reinforcing strip is formed from stainless steel, and the wiper blade has a total length of 340 millimeters and attaches the wiper blade to the printhead. 22 has six slots on one edge through which a screw can be inserted.
With a width of millimeters and a thickness of 0.5 millimeters, the stainless steel blade is glued to the edge opposite the said edge, which is provided with slots for threading screws. It is fixed and has the same length as the length of the wiper blade, a width of 5 mm, a thickness of 0.1 mm, and a protrusion projecting 0.5 mm from the free edge of the wiper blade.

[0011] Yet another aspect of the present invention aims to make the screen printing process disclosed in the co-pending application more effective.

[0012] As previously mentioned, previously proposed processes use a chamber that houses a printing product therein. With the use of the chamber, the product is discharged and the amount of the product in the chamber gradually decreases. When the chamber is emptied, the empty chamber needs to be replaced with a new chamber before the printing process can continue. The used chamber is then returned to the manufacturer for replenishment (which is expensive) or discarded (
This is wasteful and can damage the environment.) In either case, the printing process must be paused to allow for chamber replacement.

[0013] To alleviate at least some of these and other problems, a second aspect of the present invention is a self-contained printhead for a screen printer, comprising a body and a printing product. Wherein the printing product can be discharged from the container through an orifice, and the body has one or more filling openings in communication with the container, which can refill the printing product into the container as needed. And each opening is associated with a corresponding sealing means operable to enable or disable communication with said container; said sealing means discharging the printing product from each opening during a printing operation. Operation to disable communication with the container to prevent the print head from printing. Operable to communicate with the container to inject a printing product into the container when not involved, temporarily refilling the container by attaching an external printing product injector to one or more of the openings; For this purpose, an operation of injecting a printing product into the container can be performed as needed. This aspect of the invention allows a user of the chamber to inject a printing product into the chamber to refill the chamber, thereby
Prevent the expense and waste associated with previously proposed arrangements.

The present invention will be described by way of examples with reference to the accompanying drawings.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, as shown in FIGS. 1 to 3, a print head 1 includes a main body 2 having a lower chamber 4 for receiving a product to be printed, and a plurality of chambers 4 for the chamber 4. It has an end sealing block 5 and wiper blades 6 provided one on each side of the chamber 4, each wiper blade 6 being gripped by means of a mounting bar 7, which has a screw 8 The screw 8 extends through a slot provided at the edge of each wiper blade 6 and is screwed into a screw hole of the main body 2.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] Detailed description of the invention

[Correction method] Change

[Correction contents]

DETAILED DESCRIPTION OF THE INVENTION

In this embodiment, the printing product container is formed by a plurality of inner walls of a diaphragm 52 housed in an upper section 35, a center section and a lower section 38. As shown in FIG. 7, the body 32 has one or more sealing means 40 in its front wall. In the preferred embodiment, three sealing means 40 are provided in the front wall of the printhead 30, but may be more or less, and these may be in the front wall of the printhead 30. It is not always necessary to arrange them.

Preferably, each sealing means comprises a valve assembly such as a ball valve. Alternatively, each sealing means may include a cap for closing a channel communicating with the interior of the printing product container.

As shown in FIG. 9, in a preferred embodiment, each valve assembly 40 has a channel 46 within which a ball 42 is movably retained. When the print head 30 is used, the pressure applied to the printing product container causes the ball 42 to
6 to close the passage communicating with the interior of the printhead 30.

At other times (for example, the print head is rearranged in a printing device (not shown),
When pressure is released from the printing product container), a new printing product is injected under pressure into the printhead 30 by one or more valve assemblies 40 to move the ball 42 to open the passage 46. I do.

When refilling the printhead 30, the printhead 30 can be left in the printing device or removed from the printing device.

[0034] Instead of a valve assembly, a simple cap or plug, or stopper, may be provided. When the cap is in place, the cap closes the channel that communicates with the printing product container, and the cap is snap-fitted to the channel or screwed to the outer or inner wall of the channel. obtain.

The plug, or plug, can be pressed into a friction fit with the wall of the channel. Alternatives to these are obvious.

This second aspect of the invention may be used in combination with the first aspect, or may be other types of printheads, such as those disclosed in the co-pending application. Understand that it may be used within. Finally, it is understood that aspects of the present invention are disclosed for illustrative purposes only, and that modifications may be made within the scope of the present invention.

──────────────────────────────────────────────────続 き Continuing the front page (72) Inventors McClaird, Neil, MacMillan, UK, Dorsett DT40NP, Weymouth, Bryn Road 20 (72) Inventors Ricketts, Andrieu, Charles UK, Dorset DT3 6QN, Weymouth, Eastdown Avenue 27 F term (reference) 2C035 AA06 FD01 FD35 FD37 FD43 FD44

Claims (24)

[Claims] 1. A wiper blade for screen printing, comprising a web of synthetic material mounted on a printhead near one of its longitudinal edges, wherein the web of synthetic material extends toward the screen. And having a leading angle during a printing operation, a metal stiffener positioned on the other longitudinal edge of the wiper blade, the metal stiffener also functioning as a wearstrip, and during a printing operation. A wiper blade comprising contacting said screen. 2. The blade according to claim 1, wherein the metal member has a thickness equal to or less than a thickness of the synthetic wiper blade. 3. The metal member has a thickness of 10 to 70 times the thickness of the synthetic wiper blade.
The blade of claim 1 having a thickness of about 0.1%. 4. The blade according to claim 1, wherein the metal member has a thickness of about 20% of a thickness of the synthetic wiper blade. 5. The blade according to claim 1, wherein the metal member has a width equal to or less than a width of the synthetic wiper blade. 6. The blade according to claim 1, wherein the metal member has a width of 10 to 40% of a width of the wiper blade. 7. The blade according to claim 1, wherein the metal member has a width of about 23% of a width of the wiper blade. 8. The metal member is flush with the free edge of the blade or extends beyond the free edge of the composite wiper blade by up to 30% of the width of the metal member. The blade according to any one of claims 1 to 7. 9. The blade according to claim 1, wherein the metal reinforced wear strip is made of stainless steel. 10. A print head for a screen printing machine, comprising at least one blade according to claim 1. Description: 11. A printhead for a screen printer, comprising a body, a container for a printing product, and one or more filling openings operable to inject the printing product into said container. And a printhead having a corresponding sealing means associated with each opening to prevent the printing product from being ejected from the openings during a printing operation. 12. The printhead of claim 9, wherein the closure means is operable to allow the printing product to be injected into the container when the printhead is not involved in a printing operation. 13. The printhead according to claim 11, comprising a pair of blades according to claim 1, wherein the pair of blades are arranged on both sides of the orifice, respectively. 14. The printhead according to claim 11, wherein the container is formed by at least a part of an inner wall of the main body. 15. The printhead according to claim 14, wherein the container is formed by a diaphragm gripped between two opposing inner walls of the main body, and a part of the main body inner wall. 16. The printhead according to claim 15, wherein the diaphragm has a “top hat” shaped cross section. 17. The print head according to claim 15, wherein the diaphragm is made of rubber. 18. The method according to claim 15, wherein the body includes at least two parts that are separable from each other, and the diaphragm is gripped between two of the at least two parts. The print head according to 1. 19. The printhead according to claim 11, wherein the container has a second body, the second body being removable from the printhead. 20. The sealing means comprises a valve comprising a ball held in a channel in each of the filling openings, wherein the ball has an open position in which a printing product can be injected into the container while pressurizing the printing product; 2. The ball of claim 1, wherein the ball is movable between a closed position which prevents ejection of the printing product from the opening.
20. The print head according to any one of 1 to 19. 21. The printhead according to claim 20, wherein the ball is spring-biased to close each of the openings. 22. The printhead according to claim 11, wherein the sealing means includes a cap or plug for closing each of the filling openings. 23. A blade substantially as described with reference to any one of the attached FIGS. 1 to 6. 24. A printhead substantially as described with reference to the accompanying FIGS. 7 to 9.