JP2014061703A - Electrostatic printing equipment using insulating screen, and electrostatic printing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new electrostatic printing technology replacing a conventional electrostatic screen printing technology.SOLUTION: Electrostatic printing equipment makes powder adhere to an object by an electrostatic force. The electrostatic printing equipment of the present invention includes: an electrode 2 that is arranged above an object 1; a screen 3 that is arranged between the electrode 2 and the object 1; a friction member 4 that charges the powder 10 on the screen 3; and a voltage application device DC that applies a voltage between the electrode 2 and the object 1 to form an electrostatic field therebetween. The screen 3 is formed from an insulating material.

Description

  The present invention relates to an electrostatic printing apparatus and an electrostatic printing method for attaching a powder such as a functional powder or an edible powder to an object by electrostatic force, and more particularly, an electrostatic printing apparatus using a screen made of an insulating material. And an electrostatic printing method.

  An electrostatic screen printing apparatus is known as an apparatus for attaching powder to an object by electrostatic force. FIG. 16 is a schematic diagram showing a conventional electrostatic screen printing apparatus. As shown in FIG. 16, the electrostatic screen printing apparatus includes a stencil screen 110 disposed above an object (printed object) 100 and a rubbing brush 120 on the screen 110. A printing pattern such as characters and figures is formed on the screen 110 by a mesh net 111. As the rubbing brush 120, a soft open-cell urethane sponge is employed because of the good rubbing property of the powder with respect to the screen 110.

  By rubbing the powder 130 onto the screen 110 by the rubbing brush 120, the powder 130 is triboelectrically charged and further pushed out through the mesh net 111 of the screen 110. A DC high voltage is applied between the object 100 and the screen 110 by a DC power source DC, and an electrostatic field is formed between the object 100 and the screen 110. The charged powder passing through the mesh net 111 travels straight in the electrostatic field toward the target object 100 as a counter electrode, and adheres to the surface of the target object 100. In this way, a printing pattern such as characters and graphics on the screen 110 is printed on the surface of the object 100. Such electrostatic screen printing technology can form a uniform film made of powder on an object, and is used in a wide range of fields from confectionery to industrial products.

  As shown in FIG. 16, the electrostatic screen printing apparatus needs to separate the screen 110 from the object 100 to some extent. This is because when the screen 110 is brought into contact with the object 100 or very close to the object 100, electricity flows between the screen 110 and the object 100, and no electrostatic field is formed between them. . However, when the object 100 and the screen 110 are separated from each other, the outline of the printed shape formed on the object 100 may be slightly blurred.

JP 2002-347221 A

  It is an object of the present invention to provide a novel electrostatic printing technique that replaces the conventional electrostatic screen printing technique.

  In order to achieve the above-described object, one embodiment of the present invention is an electrostatic printing apparatus that attaches powder to an object by electrostatic force, and is disposed between an electrode and the electrode and the object. A screen, a charging means for charging the powder on the screen, and a voltage applying device for applying a voltage between the electrode and the object, wherein the screen is made of an insulating material. It is characterized by.

In a preferred aspect of the present invention, the screen is a mesh screen.
In a preferred aspect of the present invention, the mesh screen is formed of a synthetic fiber.

In a preferred aspect of the present invention, the charging means is a rubbing member that rubs the powder into the screen.
In a preferred aspect of the present invention, the electrode and the rubbing member are integrally formed.
In a preferred aspect of the present invention, the electrode and the rubbing member are formed of the same conductive material.

In a preferred aspect of the present invention, the rubbing member is a rotatable cylindrical roller.
In a preferred aspect of the present invention, the electrode is disposed at the center of the roller.
In a preferred aspect of the present invention, the apparatus further includes a relative movement mechanism that relatively moves the roller and the screen in a state where the roller is in contact with the screen.

In a preferred aspect of the present invention, a hopper for supplying the powder onto the screen is further provided.
In a preferred aspect of the present invention, the charging unit is a screen vibration mechanism that vibrates the screen.

  Another aspect of the present invention is an electrostatic printing apparatus that attaches powder to an object by electrostatic force, the electrode, a screen disposed between the electrode and the object, and a charged powder. And a voltage application device for applying a voltage between the electrode and the object, wherein the screen is made of an insulating material.

In a preferred aspect of the present invention, the screen is a mesh screen.
In a preferred aspect of the present invention, the mesh screen is formed of a synthetic fiber.
In a preferred aspect of the present invention, a screen vibration mechanism for vibrating the screen is further provided.

Still another embodiment of the present invention is an electrostatic printing method in which powder is attached to an object by electrostatic force, and a voltage is applied between the electrode and the object to form an electrostatic field, and the electrode The powder is triboelectrically charged on a screen made of an insulating material arranged between the object and the object, and the powder is attached to the object by electrostatic force.
Still another embodiment of the present invention is an electrostatic printing method in which powder is attached to an object by electrostatic force, and a voltage is applied between the electrode and the object to form an electrostatic field, and the electrode The charged powder is spread on a screen made of an insulating material disposed between the object and the object, and the powder is adhered to the object by electrostatic force.
In a preferred aspect of the present invention, the screen is a mesh screen.
In a preferred aspect of the present invention, the powder is a functional powder.
In a preferred aspect of the present invention, the object is an industrial product.

The electrostatic printing technique according to the present invention is a technique in which an electrostatic field is formed between an electrode and an object without applying a voltage to a screen, and powder is attached to the object using an electrostatic force.
According to the present invention, the following excellent effects can be obtained.
(1) Since the screen is made of an insulating material, the screen can be placed in contact with or very close to the object. As a result, a sharp outline pattern can be drawn on the object.
(2) Since the screen can be very close to the object, the thickness of the film made of powder deposited on the object can be controlled by the distance between the screen and the object.
(3) As shown in FIG. 16, in the conventional electrostatic screen printing apparatus, an electrostatic field is formed between the lower surface of the screen 110 and the object 100. In order to apply an electrostatic force to the powder 130, it is necessary to push the charged powder 130 into the electrostatic field by the rubbing brush 120. For this reason, an elastic body such as a sponge is used for the rubbing brush 120. In contrast, according to the present invention, the screen is placed in an electrostatic field, and the electrostatic field is formed not only below the screen but also above and inside (holes through which the powder passes). There is no need to push the body down the screen.
(4) As described in Patent Document 1, in the conventional electrostatic screen printing apparatus, the powder that has passed through the screen may adhere to the lower surface of the screen without moving toward the object. According to the present invention, it has been confirmed by experiments that powder is less likely to adhere to the lower surface of the screen than a conventional electrostatic screen printing apparatus. The reason why the powder is difficult to adhere is not well understood, but it is conceivable that the screen is made of an insulating material and / or electrostatic force acts on the powder in the holes of the screen.
(5) Some types of objects are strictly prohibited from mixing metal into the powder. According to the present invention, a material other than metal, such as a resin, can be used as a material for the screen. Therefore, the electrostatic printing technique according to the present invention can meet such a demand. Furthermore, since the screen is not a metal, it is also possible to use a powder that is not preferably brought into contact with the metal (for example, a powder that easily reacts with a metal).
(6) When the powder adheres to the object, the charge of the powder may change from negative to positive (or from positive to negative) due to the influence of the electric charge of the object. For example, in FIG. 16, when the electric charge of the powder 130 in contact with the object 100 changes from negative to positive, the powder 130 is attracted to the screen 110 and returns to the screen 110 against gravity. Such movement of the powder is more likely to occur as the electrostatic force is stronger. The strength of the electrostatic field is inversely proportional to the distance between the electrode and the object. Therefore, the electrostatic force acting on the powder can be weakened by increasing the distance between the electrode and the object. According to the present invention, the distance between the electrode and the object can be changed while maintaining the distance between the screen and the object, and vice versa. For example, the distance between the electrode and the object can be increased while the distance between the screen and the object is extremely shortened. Therefore, it is possible to prevent the powder from returning as described above while realizing clear printing.
(7) Since the distance between the electrode and the object can be increased, no discharge occurs between the electrode and the object. Therefore, powder that easily ignites can be used. Moreover, electrostatic printing can be performed even in an atmosphere that easily ignites.
(8) The electrostatic printing technique according to the present invention can deposit the powder on the object with a uniform thickness as in the conventional electrostatic screen printing technique. Furthermore, it is possible to form a multilayer film structure by repeatedly depositing different types of powders on the object.

1 is a schematic diagram showing an embodiment of an electrostatic printing apparatus according to the present invention. It is a figure which shows the example by which the electrode was earth | grounded. It is a schematic diagram which shows the electrostatic printing apparatus which made the screen contact the target object. It is an enlarged view which shows typically the screen which is contacting the target object. It is a figure which shows the example provided with the electrode moving mechanism which moves an electrode. It is a schematic diagram which shows other embodiment of this invention. It is a schematic diagram which shows other embodiment of this invention. It is a schematic diagram which shows other embodiment of this invention. It is a side view of the electrostatic printing apparatus shown in FIG. It is a schematic diagram which shows the modification of embodiment shown in FIG. It is a side view of the electrostatic printing apparatus shown in FIG. It is a schematic diagram which shows another modification of embodiment shown in FIG. It is a schematic diagram which shows other embodiment of this invention. It is a schematic diagram which shows other embodiment of this invention. It is a schematic diagram which shows other embodiment of this invention. It is a schematic diagram which shows the conventional electrostatic screen printing apparatus.

Embodiments of the present invention will be described below with reference to the drawings. The same reference numerals are assigned to the same elements, and duplicate descriptions thereof are omitted.
Unlike the conventional electrostatic screen printing apparatus, the electrostatic printing apparatus according to the present invention is an electrostatic printing apparatus using an insulating screen. FIG. 1 is a schematic view showing an embodiment of an electrostatic printing apparatus according to the present invention. The electrostatic printing apparatus includes an electrode 2 made of a conductive material such as a metal, a screen 3 disposed between the electrode 2 and the object 1, and a rubbing member 4 that rubs the powder 10 into the screen 3. And a DC power source DC as a voltage application device for applying a DC voltage between the electrode 2 and the object 1. Examples of the object 1 include industrial products and confectionery.

  The screen 3 is supported horizontally by a support material (not shown). The screen 3 is an insulating screen made of an insulating material. For example, the screen 3 is made of a synthetic resin. A plurality of holes 3 a that allow passage of the powder 10 are formed in the screen 3. The plurality of holes 3a are arranged according to a predetermined printing pattern. As the screen 3, a mesh screen is preferably used. In this case, the printing pattern is constituted by a mesh. The mesh screen can be composed of synthetic fibers such as nylon and polyester. In particular, a mesh screen made of nylon is advantageous in that it is cheaper and easier to manufacture than conventional stainless steel mesh screens.

  The rubbing member 4 is disposed on the screen 3. For the rubbing member 4, various materials such as an elastic material such as sponge and rubber, and a hard material such as wood and cured resin can be used. The rubbing member 4 is a charging unit that causes frictional charging by rubbing the powder 10 into the screen 3 and charges the powder 10 on the screen 3.

  The object 1 is placed on a stage 9, and the stage 9 is connected to the positive electrode of a DC power source DC and grounded. In addition, as shown in FIG. 2, the electrode 2 may be grounded in consideration of workability and safety. The electrode 2 is disposed above the object 1 on the stage 9 and is spaced apart from the object 1. The electrode 2 is connected to the negative electrode of the DC power source DC. When a DC voltage (for example, 5000 V) is applied between the electrode 2 and the object 1 by the DC power source DC, an electrostatic field is formed between the electrode 2 and the object 1. The screen 3 is located in this electrostatic field. Since the screen 3 is made of an insulating material, no voltage is applied to the screen 3 and the screen 3 is electrically insulated.

  Next, a printing method using the electrostatic printing apparatus shown in FIG. 1 will be described. The powder 10 is supplied to the upper surface of the screen 3. A voltage is applied between the electrode 2 and the object 1 to form an electrostatic field therebetween. The rubbing member 4 is rubbed against the screen 3 in a state where the powder 10 is present between the rubbing member 4 and the screen 3. As a result, the powder 10 is negatively charged by frictional charging and further rubbed into the screen 3. Since friction charging of the powder 10 occurs in an electrostatic field, an electrostatic force acts on the charged powder 10. Therefore, the powder 10 travels toward the object 1 through the hole 3 a formed in the screen 3. The powder 10 adheres to the object 1 according to a printing pattern composed of a plurality of holes 3 a formed in the screen 3.

  Depending on the type of powder, the powder may be positively charged when it is rubbed against the screen 3 by the rubbing member 4. When such powder is used, the electrode 2 is connected to the positive electrode of the DC power source DC, and the stage 9 is connected to the negative electrode of the DC power source DC.

  The rubbing member 4 may be manually brought into sliding contact with the screen 3 or may be brought into sliding contact with the screen 3 by a driving mechanism. Alternatively, the position of the rubbing member 4 may be fixed and the screen 3 may be moved relative to the rubbing member 4. Even in this case, the rubbing member 4 can rub the powder 10 into the screen 3.

  The screen 3 is placed in an electrostatic field, and the powder 10 is charged in the electrostatic field. Since the electrostatic field is formed not only below the screen 3 but also above and inside (the hole 3a through which the powder passes), there is no need to push out the powder 10 below the screen 3. Therefore, it is not necessary to use an elastic body as the rubbing member 4. The material of the rubbing member 4 is not particularly limited as long as it is a material that can cause triboelectric charging of the powder.

  According to the present invention, no voltage is applied to the screen 3 made of an insulating material. Therefore, the screen 3 can be brought into contact with or very close to the object 1. For example, as shown in FIG. 3, it is possible to place the screen 3 in contact with the object 1. According to such an arrangement, a pattern with a clear outline or a very thin linear pattern can be printed on the object 1.

  Furthermore, by bringing the screen 3 into contact with the object 1, the thickness of a printed pattern (for example, a graphic or a character) on the object 1 can be controlled by the thickness of the screen 3 itself. FIG. 4 is an enlarged view schematically showing the screen 3 in contact with the object 1. As shown in FIG. 4, the screen 3 is a mesh screen composed of a mesh net 7 and a pattern layer 8. The mesh net 7 is made of synthetic fiber such as nylon or polyester, and the pattern layer 8 is made of resin. The pattern layer 8 is formed on the lower surface of the mesh net 7. A printed pattern 8a is formed on the pattern layer 8, and the powder 10 rubbed into the screen 3 reaches the object 1 through the mesh net 7 and the printed pattern 8a, and the printed pattern along the printed pattern 8a. Is formed on the object 1.

  Since the screen 3 is in contact with the object 1, the thickness of a printed pattern (for example, a graphic or a character) formed from the powder 10 on the object 1 is determined depending on the thickness of the pattern layer 8. Is done. For example, when the thickness of the printed pattern formed on the object 1 is 80 μm, the screen 3 having the pattern layer 8 having a thickness of 80 μm is used. Thus, the thickness of the printed pattern can be controlled by the thickness of the pattern layer 8.

  As shown in FIG. 5, an electrode moving mechanism 6 connected to the electrode 2 may be provided, and the electrode 2 may be moved in parallel with the screen 3 by the electrode moving mechanism 6. According to such a configuration, it is possible to print on a larger object 1. Furthermore, the electrode 2 can be made small. The electrode moving mechanism 6 includes, for example, a combination of a belt connected to the electrode 2 and a motor that drives the belt, or a combination of a ball screw and a servo motor.

  FIG. 6 is a schematic view showing another embodiment of the present invention. In this embodiment, the electrode 2 and the rubbing member 4 are integrally formed. More specifically, the electrode 2 is fixed to the upper surface of the rubbing member 4. When rubbing the powder 10 into the screen 3, the rubbing member 4 moves together with the electrode 2.

  FIG. 7 is a schematic view showing still another embodiment of the present invention. In this embodiment, the electrode 2 and the rubbing member 4 are made of the same conductive material, and the electrode 2 and the rubbing member 4 are provided as a single member. The electrode 2 and the rubbing member 4 are elements having different functions, but the rubbing member 4 can also function as the electrode 2 by using a conductive material for the rubbing member 4. For example, a conductive resin, carbon, or the like can be used.

  FIG. 8 is a schematic view showing still another embodiment of the present invention. Since the configuration and operation that are not particularly described are the same as those in the above-described embodiment, redundant description thereof is omitted. In this embodiment, a cylindrical roller is used as the rubbing member 4. The roller (rubbing member) 4 is arranged so that its axis is parallel to the screen 3, and the outer peripheral surface of the roller 4 is in contact with the upper surface of the screen 3. FIG. 9 is a side view of the electrostatic printing apparatus shown in FIG. As shown in FIG. 9, the roller 4 is connected to a motor 12, and the motor 4 rotates the roller 4 around its axis, and the outer peripheral surface of the roller 4 is in sliding contact with the upper surface of the screen 3. In order to increase the contact area between the roller 4 and the screen 3, the roller 4 is preferably formed from an elastic material such as urethane sponge or rubber.

  The electrode 2 is configured as a support shaft for the roller 4. The electrode 2 is disposed at the center of the roller 4, and the roller 4 rotates around the electrode 2. The electrode (support shaft) 2 is connected to a DC power source DC. Therefore, an electrostatic field is formed between the electrode 2 and the object 1. As can be seen from FIG. 8, the lower part of the roller 4 positioned below the electrode 2 is placed in an electrostatic field.

  Above the roller 4, a hopper 14 for supplying the powder 10 to the outer peripheral surface of the roller 4 is disposed. The powder 10 is stored inside the hopper 14. A plurality of holes (not shown) that allow the passage of powder are formed in the bottom of the hopper 14, and a rotating brush 15 is disposed so as to cover these holes. By rotating the rotary brush 15, the powder 10 is supplied to the roller 4 through a hole at the bottom of the hopper 14. The supply amount of the powder 10 can be controlled by the rotation speed of the rotary brush 15. The powder 10 is carried to the upper surface of the screen 3 by the rotation of the roller 4. The powder 10 is rubbed into the screen 3 by the rotating roller 4 and is charged by friction. The charged powder 10 travels toward the object 1 by electrostatic force and adheres to the object 1.

  FIG. 10 is a schematic view showing a modification of the embodiment shown in FIG. 8, and FIG. 11 is a side view of the electrostatic printing apparatus shown in FIG. In this example, a relative movement mechanism 16 for moving the roller 4 with respect to the screen 3 is provided. The relative movement mechanism 16 moves the roller 4 in a direction indicated by an arrow parallel to the screen 3 in a state where the roller 4 is in contact with the upper surface of the screen 3. The moving direction of the roller 4 is a direction perpendicular to the axis of the roller 4. The hopper 14 is also connected to the relative movement mechanism 16, and the roller 4 and the hopper 14 are moved together by the relative movement mechanism 16. The roller 4 rubs the powder 10 into the screen 3 while moving on the screen 3. According to this example, the powder 10 can be attached to a larger area on the object 1. The relative movement mechanism 16 includes, for example, a combination of a belt connected to the motor 12 and the hopper 14 and a motor that drives the belt, or a combination of a ball screw and a servo motor.

  10 and 11 moves the roller 4 and the hopper 14, but as another example, the relative movement mechanism 16 moves the screen 3 horizontally relative to the roller 4 and the hopper 14. You may let them. Even in this case, the roller (rubbing member) 4 and the screen 3 can move relatively while maintaining a contact state, and the roller 4 can rub the powder 10 into the screen 3.

  FIG. 12 is a schematic diagram showing another modification of the embodiment shown in FIG. The configuration of this example is basically the same as the configuration shown in FIG. 10, but differs from the above example in that the hopper 14 is arranged alongside the roller 4. More specifically, the hopper 14 is arrange | positioned ahead with respect to the advancing direction of the roller 4 shown by the arrow. The hopper 14 supplies the powder 10 directly to the upper surface of the screen 3, and the roller 4 rubs the powder 10 on the screen 3 against the screen 3.

  Although the hopper 14 is moved by the relative movement mechanism 16 in synchronization with the roller 4, a hopper moving mechanism for moving the hopper 14 independently of the roller 4 may be provided.

  FIG. 13 is a schematic view showing still another embodiment of the present invention. As shown in FIG. 13, in this embodiment, a screen vibration mechanism 17 is provided as a charging means for charging the powder 10 on the screen 3 instead of the rubbing member 4. The screen vibration mechanism 17 causes frictional charging of the powder 10 on the screen 3 by vibrating the screen 3 in the horizontal direction.

  The electrostatic field is formed through the screen 3. Accordingly, an electrostatic force acts on the powder 10 on the charged screen 3, and the powder 10 travels toward the object 1 through the hole 3 a of the screen 3. Thus, since it is not necessary to extrude the powder 10 below the screen 3, the rubbing member 4 may be omitted. As shown in FIG. 5, the electrode 2 may be moved in parallel with the screen 3. Further, the rubbing member 4 and the screen vibration mechanism 17 may be provided side by side.

  FIG. 14 is a schematic view showing still another embodiment of the present invention. In this embodiment, a powder spraying mechanism 20 is provided above the screen 3 in place of the rubbing member 4. The powder spraying mechanism 20 stores powder therein. The powder spraying mechanism 20 has a charging device 21 such as a corona discharge device, and can charge the powder stored inside. A plurality of holes (not shown) that allow the passage of powder are formed at the bottom of the powder spraying mechanism 20, and a rotating brush 22 is disposed so as to cover the holes. By rotating the rotary brush 22, the powder stored in the powder spreading mechanism 20 is supplied onto the screen 3 through the holes. As shown by the arrows in FIG. 14, the powder spraying mechanism 20 can move in parallel with the screen 3.

  The powder spraying mechanism 20 supplies the charged powder 10 onto the screen 3 while moving in parallel with the screen 3. The powder 10 on the screen 3 travels toward the object 1 through the hole 3 a of the screen 3 by the action of electrostatic force, and adheres to the object 1. In a state where a voltage is applied between the electrode 2 and the object 1, the powder may be supplied onto the screen 3 by the powder spraying mechanism 20, or the powder may be supplied to the screen 3 by the powder spraying mechanism 20. A voltage may be applied between the electrode 2 and the object 1 after being supplied above. The screen vibration mechanism 17 described above may be incorporated in this embodiment. Furthermore, as shown in FIG. 5, the electrode 2 may be moved in parallel with the screen 3 while applying a voltage between the electrode 2 and the object 1.

  FIG. 15 is a schematic view showing still another embodiment of the present invention. In this embodiment, the electrode 2 is covered with an insulating member 25. An example of the insulating member 25 is an insulating film having a thickness of about 1 mm. The insulating member 25 covers a horizontal surface (bottom surface) facing the screen 3 of the electrode 2 and a side surface connected to the horizontal surface. By covering the electrode 2 with the insulating member 25, even if the distance between the electrode 2 and the object 1 is shortened, it becomes difficult for discharge to occur between them. Therefore, accidents such as explosions and fires can be prevented. In addition, powder that easily ignites can be used, and electrostatic printing can be performed in an atmosphere that easily ignites.

According to the present invention, the following excellent effects can be obtained.
(1) Since the screen 3 is made of an insulating material, the screen 3 can be placed in contact with the object 1 or placed very close to it. As a result, a sharp outline pattern can be drawn on the object 1.
(2) Since the screen 3 can be very close to the object 1, the thickness of the film made of powder deposited on the object 1 is controlled by the distance between the screen 3 and the object 1. Can do.
(3) As shown in FIG. 16, in the conventional electrostatic screen printing apparatus, an electrostatic field is formed between the lower surface of the screen 110 and the object 100. In order to apply an electrostatic force to the powder 130, it is necessary to push the charged powder 130 into the electrostatic field by the sliding brush 120. For this reason, an elastic body such as a sponge is used for the rubbing brush 120. On the other hand, according to the present invention, the screen 3 is placed in an electrostatic field, and the electrostatic field is formed not only below the screen 3 but also above and inside (hole 3a through which the powder passes). Therefore, it is not necessary to extrude the powder below the screen 3.
(4) As described in Patent Document 1, in the conventional electrostatic screen printing apparatus, the powder that has passed through the screen may adhere to the lower surface of the screen without moving toward the object. According to the present invention, it has been confirmed by experiments that powder is less likely to adhere to the lower surface of the screen 3 than a conventional electrostatic screen printing apparatus. The reason why the powder is difficult to adhere is not well understood, but it is conceivable that the screen 3 is made of an insulating material and / or that an electrostatic force acts on the powder in the holes of the screen.
(5) Some types of objects are strictly prohibited from mixing metal into the powder. According to the present invention, as the material of the screen 3, a material other than metal, such as a resin, can be used. Therefore, the electrostatic printing technique according to the present invention can meet such a demand. Furthermore, since the screen 3 is not a metal, it is also possible to use a powder that is not preferably brought into contact with the metal (for example, a powder that easily reacts with the metal).
(6) When the powder adheres to the object, the charge of the powder may change from negative to positive (or from positive to negative) due to the influence of the electric charge of the object. For example, in FIG. 16, when the electric charge of the powder 130 in contact with the object 100 changes from negative to positive, the powder 130 is attracted to the screen 110 and returns to the screen 110 against gravity. Such movement of the powder 130 is more likely to occur as the electrostatic force increases. The strength of the electrostatic field is inversely proportional to the distance between the electrode and the object. Therefore, the electrostatic force acting on the powder can be weakened by increasing the distance between the electrode and the object. According to the present invention, it is possible to change the distance between the electrode 2 and the object 1 while maintaining the distance between the screen 3 and the object 1 and vice versa. For example, the distance between the electrode 2 and the object 1 can be increased while the distance between the screen 3 and the object 1 is extremely shortened. Therefore, it is possible to prevent the powder from returning as described above while realizing clear printing.
(7) Since the distance between the electrode 2 and the object 1 can be increased, no discharge occurs between the electrode 2 and the object 1. Therefore, powder that easily ignites can be used. Moreover, electrostatic printing can be performed even in an atmosphere that easily ignites.
(8) The electrostatic printing technique according to the present invention can deposit powder on the object 1 with a uniform thickness, as in the conventional electrostatic screen printing technique. Furthermore, it is also possible to form a multilayer structure by repeatedly depositing different types of powders on the object 1.

  Examples of powders that can be used in the present invention include edible powders and functional powders. Functional powder includes electrode powder, insulating powder, conductive powder constituting wiring and conductive film, carbon powder, metal powder, resin powder, pigment, powder paint, powder rubber, semiconductor It includes powders, powdered chemicals, and other functional powders that act on electrostatic forces.

  In addition, the present invention can be applied to all products in which functional powder is used, and examples thereof include primary batteries, secondary batteries, chemical cells such as fuel cells, physical cells such as solar cells, liquid crystal displays, Display devices such as plasma displays and organic EL displays, parts of power machines such as internal combustion engines, cosmetics, daily goods, articles with pictures, household goods, clothing, footwear, semiconductor devices, electrical elements such as capacitors and diodes, Parts of manufacturing equipment and processing machinery, parts of vehicles (automobiles, bicycles, motorcycles, railways, aircrafts, ships, etc.), medical equipment, cooking utensils, stationery, building materials, glass products, furniture, sports equipment, textiles, rugs, Examples include play equipment.

  The above-listed functional powders and products are merely examples, and the present invention can be applied not only to the existing functional powders and products as described above, but also to completely new functional powders and products. .

  Furthermore, according to the present invention, functional powders can be laminated, so that it is possible to produce a product that has not existed in the past.

  The above-described embodiments can be appropriately combined.

  The present invention is not limited to the above-described embodiments, but should be construed most widely in accordance with the description of the scope of claims.

1 Object (printed material)
2 electrode 3 screen 4 rubbing member 6 electrode moving mechanism 7 mesh net 8 pattern layer 9 stage 10 powder 12 motor 14 hopper 15 rotating brush 16 relative moving mechanism 17 screen vibrating mechanism 20 powder spraying mechanism 21 charging device 22 rotating brush 25 insulation Element

Claims (23)

An electrostatic printing apparatus that attaches powder to an object by electrostatic force,
Electrodes,
A screen disposed between the electrode and the object;
Charging means for charging the powder on the screen;
A voltage applying device that applies a voltage between the electrode and the object;
The electrostatic printing apparatus, wherein the screen is made of an insulating material.   The electrostatic printing apparatus according to claim 1, wherein the screen is a mesh screen.   The electrostatic printing apparatus according to claim 2, wherein the mesh screen is formed of a synthetic fiber.   The electrostatic printing apparatus according to claim 1, wherein the charging unit is a rubbing member that rubs the powder into the screen.   The electrostatic printing apparatus according to claim 4, wherein the electrode and the rubbing member are integrally formed.   The electrostatic printing apparatus according to claim 4, wherein the electrode and the rubbing member are made of the same conductive material.   The electrostatic printing apparatus according to claim 4, wherein the rubbing member is a rotatable cylindrical roller.   The electrostatic printing apparatus according to claim 7, wherein the electrode is disposed at a center of the roller.   The electrostatic printing apparatus according to claim 7, further comprising a relative movement mechanism that relatively moves the roller and the screen in a state where the roller is in contact with the screen.   The electrostatic printing apparatus according to claim 1, further comprising a hopper that supplies the powder onto the screen.   The electrostatic printing apparatus according to claim 1, wherein the charging unit is a screen vibration mechanism that vibrates the screen. An electrostatic printing apparatus that attaches powder to an object by electrostatic force,
Electrodes,
A screen disposed between the electrode and the object;
A powder spreading mechanism for spreading the charged powder on the screen;
A voltage applying device that applies a voltage between the electrode and the object;
The electrostatic printing apparatus, wherein the screen is made of an insulating material.   The electrostatic printing apparatus according to claim 12, wherein the screen is a mesh screen.   The electrostatic printing apparatus according to claim 13, wherein the mesh screen is formed of a synthetic fiber.   The electrostatic printing apparatus according to claim 12, further comprising a screen vibration mechanism that vibrates the screen. An electrostatic printing method for attaching powder to an object by electrostatic force,
A voltage is applied between the electrode and the object to form an electrostatic field,
The powder is triboelectrically charged on a screen made of an insulating material disposed between the electrode and the object, and the powder is attached to the object by electrostatic force. Electric printing method.   The electrostatic printing method according to claim 16, wherein the screen is a mesh screen.   The electrostatic printing method according to claim 16, wherein the powder is a functional powder.   The electrostatic printing method according to claim 16, wherein the object is an industrial product. An electrostatic printing method for attaching powder to an object by electrostatic force,
A voltage is applied between the electrode and the object to form an electrostatic field,
Electrostatic printing, characterized in that a charged powder is dispersed on a screen made of an insulating material disposed between the electrode and the object, and the powder is adhered to the object by electrostatic force. Method.   21. The electrostatic printing method according to claim 20, wherein the screen is a mesh screen.   The electrostatic printing method according to claim 20, wherein the powder is a functional powder.   The electrostatic printing method according to claim 20, wherein the object is an industrial product.

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