JP2019098745A - Hopper for supplying pulverulent body and electrostatic screen printing device including the hopper - Google Patents

Abstract

To provide a hopper that can prevent crosslinking with a pulverulent body inside a hopper box and stably supply the pulverulent body.SOLUTION: A hopper 1 includes: a hopper box 2 with a bottom part 2a formed with a through-hole 3 through which a pulverulent body passes; a turning drum 5 disposed inside the hopper box 2 and pushing out the pulverulent body from the hopper box 2 to the outside of the hopper box 2 via the through-hole 3; and a pulverulent body stirring mechanism 10 disposed inside the hopper box 2 and convecting the pulverulent body inside the hopper box 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hopper for supplying a powder such as edible powder or functional powder. The invention also relates to an electrostatic screen printing apparatus provided with such a hopper.

  An apparatus for spraying powder on or adhering to the surface of an object is provided with a hopper for containing the powder. The powder is contained in a hopper box having through holes, and by rotating the hopper brush in the hopper box, the powder is pushed out of the hopper box through the through holes. Such hoppers are often used, for example, in electrostatic screen printing devices.

  An electrostatic screen printing apparatus adheres powder such as functional powder and edible powder to the surface of an object using electrostatic force, and prints a printing pattern such as characters and figures on the surface of the object It is an apparatus (for example, refer patent document 1). FIG. 10 is a schematic view showing a conventional electrostatic screen printing apparatus. As shown in FIG. 10, the electrostatic screen printing apparatus comprises a screen 110 disposed above the object 100, a sponge roller 112 placed on the screen 110, and a hopper 114 for supplying powder to the sponge roller 112. And have. The screen 110 and the object 100 are not in contact with each other. The screen 110 has a mesh 111 of a predetermined shape such as characters and figures.

  The hopper 114 includes a hopper box 114a for containing powder and a hopper brush 114b for pushing out the powder from the hopper box 114a. When the hopper brush 114b is rotated, the powder in the hopper box 114a is supplied to the sponge roller 112 through a slit (not shown) provided at the bottom of the hopper box 114a.

  The powder supplied from the hopper 114 to the sponge roller 112 is conveyed to the screen 110 by the rotation of the sponge roller 112. Then, the powder is scraped into the mesh 111 of the screen 110 by the rotating sponge roller 112 and pushed out below the screen 110 through the mesh 111. The powder is frictionally charged by being rubbed into the mesh 111 of the screen 110 by the rotating sponge roller 112. While rubbing the powder, the sponge roller 112 is moved on the screen 110 as shown by the arrow in FIG.

  A DC voltage is applied between the object 100 and the screen 110 by a power source DC, and an electrostatic field is formed between the object 100 and the screen 110. The powder charged through the mesh 111 adheres to the surface of the object 100 while traveling straight toward the object 100 as a counter electrode in the electrostatic field. In this manner, a print pattern such as characters or graphics formed on the screen 110 is printed on the surface of the object 100. Such electrostatic screen printing technology is used in a wide range of fields from confectionery to industrial products, because a film made of powder can be uniformly formed on an object.

JP, 2002-347221, A

  In order to uniformly form a film made of powder on an object, it is necessary to supply the powder from the hopper 114 to the sponge roller 112 at a constant flow rate. However, as the hopper brush 114b rotates, the powders may solidify in the hopper box 114a to form so-called crosslinking. In particular, moist powders such as sugar tend to form crosslinks in the hopper box 114a. When the powder is crosslinked in the hopper box 114a, even if the hopper brush 114b is rotated, the powder is not discharged from the hopper box 114a, and as a result, good printing can not be performed.

  Then, this invention prevents the bridge | crosslinking of the powder in a hopper box, and it aims at providing the hopper which can supply powder stably. Another object of the present invention is to provide an electrostatic screen printing apparatus provided with such a hopper.

  According to one aspect of the present invention, there is provided a hopper box having a bottom portion formed with a through hole through which powder can pass, and the hopper box disposed in the hopper box and having the powder in the hopper box through the through hole. The hopper is provided with a rotary drum which is pushed out, and a powder stirring mechanism which is disposed in the hopper box and which causes the powder in the hopper box to circulate.

The powder stirring mechanism is disposed in the hopper box, and is disposed at a position higher than the first stirring impeller, and is disposed in the hopper box, and the first stirring impeller is positioned higher than the rotating drum. It is characterized by comprising a second stirring impeller, and a rotating device for rotating the first stirring impeller and the second stirring impeller in the direction opposite to the rotation direction of the rotating drum.
The rotation axis of the first stirring impeller is located downstream of the top of the rotary drum in the rotation direction of the rotary drum.
The rotary shaft center of the second stirring impeller is located between the rotary shaft center of the rotary drum and the rotary shaft center of the first stirring impeller when viewed from above the hopper box. It is characterized by
The rotating device rotates the first stirring impeller and the second stirring impeller at a speed higher than that of the rotating drum.
The hopper box is characterized by having a rectangular horizontal cross section.
The axis of rotation of the rotary drum may be parallel to the bottom of the hopper box.

The hopper further includes a baffle plate disposed in the hopper box, and an edge of the baffle plate is disposed in proximity to the outer peripheral surface of the rotating drum.
The hopper further comprises a screw conveyor arranged in the hopper box, the screw conveyor being adjacent to the lower part of the rotating drum and the lowermost part of the rotating drum in the direction of rotation of the rotating drum It is characterized in that it is located upstream of the vehicle.
The hopper further comprises a powder stopper adjacent to a lower portion of the rotary drum, the powder stopper being fixed to a bottom portion of the rotary drum, and in the rotation direction of the rotary drum It is characterized in that it is located upstream of the lowermost part.

  One embodiment of the present invention is an electrostatic screen printing apparatus for adhering powder to an object by electrostatic force, which comprises a screen having a mesh of a predetermined shape, and a sponge roller for rubbing the powder into the screen. A motor for rotating the sponge roller about its axis, the hopper for supplying the powder onto the sponge roller, and a power source for applying a voltage between the screen and an object Do.

  According to the present invention, the powder above the rotating drum flows by the rotation of the rotating drum and the powder stirring mechanism to form a circulating flow in the hopper box. That is, since the powder located above the rotating drum does not stay in a fixed place, it does not form crosslinks. Therefore, the hopper can be stably supplied to the outside of the hopper box through the powder passage as the rotary drum rotates.

It is a sectional view showing one embodiment of a hopper concerning the present invention. It is a top view of a hopper. It is a side view of the hopper seen from the direction shown by arrow A of FIG. It is a side view of the hopper seen from the direction shown by arrow B of FIG. It is sectional drawing which shows other embodiment of a hopper. It is sectional drawing which shows the further another embodiment of a hopper. It is a figure of the screw conveyor seen from the direction shown by arrow C of FIG. It is a schematic diagram which shows the electrostatic screen printing apparatus provided with the hopper mentioned above. It is a side view of the electrostatic screen printing apparatus shown in FIG. It is a schematic diagram which shows the conventional electrostatic screen printing apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view showing an embodiment of the hopper according to the present invention, and FIG. 2 is a top view of the hopper. As shown in FIG. 1, the hopper 1 is disposed in a hopper box 2 for containing powder inside, a rotating drum 5 and the hopper box 2, and is a powder for convecting the powder in the hopper box 2. A stirring mechanism 10 is provided. The powder stirring mechanism 10 includes a first stirring impeller 11 and a second stirring impeller 21. The hopper box 2 has a bottom 2a in which a through hole 3 through which powder can pass is formed. Both sides of the bottom 2 a are inclined downward toward the through hole 3. The hopper box 2 has a rectangular horizontal cross section.

  The rotating drum 5, the first stirring impeller 11 and the second stirring impeller 21 are disposed in the hopper box 2. The rotary drum 5, the first stirring impeller 11, and the second stirring impeller 21 are configured to be rotatable around their respective rotation axes O1, O2, and O3. The rotational axes O1, O2, and O3 of the rotary drum 5, the first stirring impeller 11, and the second stirring impeller 21 are parallel to the bottom 2a of the hopper box 2. The rotary drum 5 has a function of pushing out the powder in the hopper box 2 to the outside of the hopper box 2 through the through hole 3, and the first stirring impeller 11 and the second stirring impeller 21 are in the hopper box 2. It has the function of stirring the powder and fluidizing the powder.

  The rotating drum 5 is disposed close to the bottom 2 a of the hopper box 2 and is not in contact with the bottom 2 a. For example, the gap between the rotary drum 5 and the bottom 2a of the hopper box 2 is 1 mm to 3 mm. In the present embodiment, the rotary drum 5 includes a drum shaft 6 rotatably supported by the hopper box 2, a cylindrical body 7 fixed to the drum shaft 6, and a plurality of stirrings fixed to the outer peripheral surface of the cylindrical body 7. It has a rod 8. The drum shaft 6 and the cylindrical body 7 are integrally rotatable. The plurality of stirring rods 8 extend in parallel with the axial center of the cylindrical body 7 (that is, the rotational axis O1), and are arranged at equal intervals around the rotational axis O1. Instead of the plurality of stirring rods 8, a plurality of grooves may be formed on the outer peripheral surface of the cylindrical body 7 extending in parallel with the axial center of the cylindrical body 7 (that is, the rotational axis O1). In one embodiment, the rotating drum 5 may be composed of a cylindrical sponge. In this case, the rotary drum 5 may contact the bottom 2 a of the hopper box 2.

  The rotation axis O1 of the rotary drum 5, the rotation axis O2 of the first stirring impeller 11, and the rotation axis O3 of the second stirring impeller 21 are parallel to each other. The first stirring impeller 11 is disposed at a position higher than the rotary drum 5, and the second stirring impeller 21 is disposed at a position higher than the first stirring impeller 11. More specifically, the rotation axis O2 of the first stirring impeller 11 is disposed at a position higher than the rotation axis O1 of the rotating drum 5, and the rotation axis O3 of the second stirring impeller 21 is the first stirring blade It is disposed at a position higher than the rotation axis O2 of the car 11.

  The first stirring impeller 11 has a shaft 12 rotatably supported by the hopper box 2 and a plurality of stirring paddles 14 fixed to the shaft 12. Similarly, the second stirring impeller 21 has a shaft 22 rotatably supported by the hopper box 2 and a plurality of stirring paddles 24 fixed to the shaft 22. The first stirring impeller 11 and the second stirring impeller 21 rotate in the same direction to stir the powder in the hopper box 2. The rotation direction of the first stirring impeller 11 and the second stirring impeller 21 is opposite to the rotation direction of the rotating drum 5.

  The rotation axis O2 of the first stirring impeller 11 is located downstream of the top of the rotary drum 5 in the rotation direction of the rotary drum 5. Similarly, the rotation axis O3 of the second stirring impeller 21 is located downstream of the top of the rotary drum 5 in the rotation direction of the rotary drum 5. As shown in FIG. 2, when viewed from above the hopper box 2, the rotation axis O3 of the second stirring impeller 21 is the rotation axis O1 of the rotating drum 5 and the rotation axis of the first stirring impeller 11. Located between O2 and

  3 is a side view of the hopper 1 seen from the direction shown by the arrow A in FIG. 2, and FIG. 4 is a side view of the hopper 1 seen from the direction shown by the arrow B in FIG. The powder stirring mechanism 10 further includes a rotating device that rotates the first stirring impeller 11 and the second stirring impeller 21 in the direction opposite to the rotation direction of the rotating drum 5. This rotation device is fixed to the drum shaft 6 of the rotary drum 5 with a first gear 31 and a second gear 32 fixed to one end of the shaft 12 of the first stirring impeller 11 and meshed with the first gear 31. A first sprocket 35 fixed to the other end of the shaft 12 of the first stirring impeller 11, a second sprocket 36 fixed to the shaft 22 of the second stirring impeller 21, and a first sprocket 35; It has a chain 38 hung on a second sprocket 36. The drum shaft 6 of the rotary drum 5 is connected to an electric motor (described later). In one embodiment, in place of the first sprocket 35, the second sprocket 36, and the chain 38, as long as the first stirring impeller 11 and the second stirring impeller 21 rotate in the same direction, a combination of pulleys and belts, or A combination of gears may be used.

  The diameter of the first gear 31 is larger than the diameter of the second gear 32, and the diameter of the first sprocket 35 and the diameter of the second sprocket 36 are the same. Therefore, the first stirring impeller 11 connected to the second gear 32 rotates at a higher speed than the rotary drum 5 connected to the first gear 31, and the first stirring impeller connected to the first sprocket 35. 11 rotates at the same speed as the second stirring impeller 21 connected to the second sprocket 36. The first stirring impeller 11 and the second stirring impeller 21 rotate in synchronization with the rotating drum 5.

  According to the hopper 1 having such a configuration, the powder located above the rotary drum 5 flows as the rotary drum 5, the first stirring impeller 11, and the second stirring impeller 21 rotate, as shown in FIG. A circulating flow is formed in the hopper box 2 as indicated by the dotted arrow in FIG. That is, the powder rises along the side wall of the hopper box 2 by the rotation of the first stirring impeller 11, and further rises along the side of the hopper box 2 by the rotation of the second stirring impeller 21, and then The descent toward the rotary drum 5 over the stirring impeller 21. In order to raise the powder along the side wall of the hopper box 2 by the rotation of the first stirring impeller 11, it is preferable that the first stirring impeller 11 be as close as possible to the inner surface of the side wall of the hopper box 2. For example, the distance between the stirring paddle 14 and the inner surface of the side wall of the hopper box 2 when the rotating stirring paddle 14 comes closest to the inner surface of the side wall of the hopper box 2 is less than 5 mm, preferably 1 mm or less.

  Thus, according to the powder stirring mechanism 10 provided with the first stirring impeller 11 and the second stirring impeller 21, the powder located above the rotary drum 5 always flows (circulates) and is kept at a fixed place. Since it does not stay, it does not form crosslinks. Therefore, the hopper 1 can stably supply the powder to the outside of the hopper box 2 through the through holes 3 as the rotary drum 5 rotates.

  FIG. 5 is a cross-sectional view showing another embodiment of the hopper 1. The configuration of the present embodiment, which is not particularly described, is the same as that of the embodiment shown in FIGS. In the present embodiment, the hopper 1 is provided with a baffle plate 40 adjacent to the top of the rotating drum 5. The baffle plate 40 is disposed in the hopper box 2 and fixed to the side wall of the hopper box 2. The baffle plate 40 extends in parallel with the drum shaft 6 of the rotary drum 5. A gap of a predetermined size is formed between the edge of the baffle plate 40 and the outer peripheral surface of the rotary drum 5. The size of the gap is in the range of 0.1 mm to 5 mm. The baffle plate 40 may be in contact with the outer peripheral surface of the rotating drum 5 depending on the material of the rotating drum 5 and the type of powder.

  The baffle plate 40 is disposed horizontally and extends over the entire width of the rotary drum 5. The baffle plate 40 is located downstream of the top of the rotary drum 5 in the rotational direction of the rotary drum 5. The baffle plate 40 is located lower than the top of the rotary drum 5 and is located below the first stirring impeller 11. The baffle plate 40 is made of metal or resin.

  The baffle plate 40 arranged in this way mainly has two functions. The first function is to receive the weight of the powder in the hopper box 2. When a large amount of powder is charged into the hopper box 2, the powder moves downward toward the through hole 3 formed in the bottom 2 a of the hopper box 2 by its own weight. As a result, a large amount of powder is pushed out of the through hole 3. On the other hand, when the amount of powder charged into the hopper box 2 is small, the weight of the powder does not contribute much to the downward movement of the powder. As a result, a small amount of powder is pushed out of the through hole 3.

  As described above, the amount of powder supplied from the hopper 1 changes according to the amount of powder introduced into the hopper box 2. The baffle plate 40 can reduce such variation in the amount of supplied powder. That is, the baffle plate 40 supports the powder charged into the hopper box 2 and can prevent the weight of the powder on the upper side from being applied to the powder on the lower side. Therefore, the baffle plate 40 can stabilize the amount of powder supplied from the hopper 1.

  The second function of the baffle plate 40 is to limit the flow rate of the powder fed to the through holes 3 of the hopper box 2 by the rotary drum 5. The powder is dragged by the outer peripheral surface of the rotary drum 5 and sent to the through hole 3. Since the edge of the baffle plate 40 is disposed in contact with or in close proximity to the outer circumferential surface of the rotary drum 5, the flow rate of powder dragged downward by the rotary drum 5 is limited by the baffle plate 40. As a result, the powder is sent to the through hole 3 at a constant flow rate, and the amount of powder supplied from the hopper 1 is stabilized. The powder separated from the rotary drum 5 by the baffle plate 40 is raised again by the rotating first stirring impeller 11.

  FIG. 6 is a cross-sectional view showing another embodiment of the hopper 1. The configuration of the present embodiment, which is not particularly described, is the same as that of the embodiment shown in FIG. In the present embodiment, the hopper 1 includes a screw conveyor 42 disposed in the hopper box 2. The screw conveyor 42 is adjacent to the lower part of the rotating drum 5. The screw conveyor 42 is located upstream of the lowermost portion of the rotary drum 5 in the rotational direction of the rotary drum 5.

  FIG. 7 is a view of the screw conveyor 42 viewed from the direction indicated by the arrow C in FIG. The screw conveyor 42 is disposed at the corner of the bottom 2 a of the hopper box 2. A through hole 2 b is formed on the side wall of the hopper box 2. One end of the screw conveyor 42 protrudes to the outside of the hopper box 2 through the through hole 2 b.

  One end of the shaft 42 a of the screw conveyor 42 is rotatably supported by a support member 46 fixed to the hopper box 2. A third gear 45 meshing with the first gear 31 is fixed to the other end of the shaft 42 a of the screw conveyor 42. When the rotary drum 5 and the first gear 31 rotate, the third gear 45 and the screw conveyor 42 rotate, and the screw conveyor 42 discharges the powder from the hopper box 2 to the outside of the hopper box 2.

  According to the present embodiment, the screw conveyor 42 can prevent the powder compressed at the bottom 2 a of the hopper box 2 from accumulating. Thus, the rotary drum 5 can supply a stable amount of powder to the hole 3.

  In the present embodiment, as shown in FIG. 6, the hopper 1 further includes a powder stopper 47 disposed in the hopper box 2. The powder stopper 47 is fixed to the bottom 2 a of the hopper box 2 and is disposed in the vicinity of the lower part of the rotary drum 5. The powder stopper 47 extends over the entire width of the rotary drum 5. The powder stopper 47 is located upstream of the lowermost portion of the rotary drum 5 in the rotation direction of the rotary drum 5. A gap is formed between the powder stopper 47 and the outer peripheral surface of the rotary drum 5. The size of the gap is in the range of 0.1 mm to 5 mm. The powder stopper 47 may be in contact with the outer peripheral surface of the rotating drum 5 depending on the material of the rotating drum 5 and the type of powder. The flow rate of the powder dragged toward the through hole 3 by the rotating drum 5 is limited by the powder stopper 47. As a result, the powder is sent to the through hole 3 at a constant flow rate, and the amount of powder supplied from the hopper 1 is stabilized. The powder stopper 47 is made of metal or resin.

  FIG. 8 is a schematic view showing an electrostatic screen printing apparatus provided with the hopper 1 described above, and FIG. 9 is a side view of the electrostatic screen printing apparatus shown in FIG. The electrostatic screen printing apparatus comprises a screen 51 disposed above the object 50, a sponge roller 53 placed on the screen 51, an electric motor 54 for rotating the sponge roller 53 around its axis, and powder. The above-described hopper 1 for supplying to the sponge roller 53 is provided. The hopper 1 is a hopper according to the embodiment shown in FIGS. 1 to 4, but may be a hopper according to the embodiment shown in FIG. 5 or a hopper according to the embodiments shown in FIGS. 6 and 7. The screen 51 and the object 50 are not in contact with each other. The screen 51 has a mesh 60 of a predetermined shape such as characters and figures.

  The drum shaft 6 of the hopper 1 is connected to the motor 65. The motor 5 is rotated by the motor 65, whereby the powder is supplied from the hopper 1 to the sponge roller 53. The powder supplied from the hopper 1 to the sponge roller 53 is conveyed to the screen 51 by the rotation of the sponge roller 53. Then, the powder is rubbed into the mesh 60 of the screen 51 by the rotating sponge roller 53 and pushed out below the screen 51 through the mesh 60. The powder is frictionally charged by being rubbed against the mesh 60 of the screen 51 by the rotating sponge roller 53. While rubbing the powder, the sponge roller 53 moves on the screen 51 as shown by the arrow in FIG. Instead of moving the sponge roller 53, the screen 51 may be moved.

  The object 50 is placed on the mounting table 62. The positive electrode of the power source DC is electrically connected to the mounting table 62, and the negative electrode of the power source DC is electrically connected to the screen 51. Depending on the type of powder, the negative electrode of the power source DC may be electrically connected to the mounting table 62, and the positive electrode of the power source DC may be electrically connected to the screen 51.

  A DC voltage is applied between the object 50 and the screen 51 by a power source DC, and an electrostatic field is formed between the object 50 and the screen 51. The powder charged through the mesh 60 adheres to the surface of the object 50 straight in the electrostatic field toward the object 50 serving as a counter electrode. In this manner, a print pattern such as characters and figures formed on the screen 51 is printed on the surface of the object 50. Such electrostatic screen printing technology is used in a wide range of fields from confectionery to industrial products, because a film made of powder can be uniformly formed on an object.

  Although the embodiment shown in FIGS. 8 and 9 is an example in which the hopper 1 is applied to an electrostatic screen printing apparatus, the hopper 1 is not limited to the electrostatic screen printing apparatus, but may be applied to other types of apparatus that handle powder. It is possible to apply.

  The embodiments described above are described for the purpose of enabling one skilled in the art to which the present invention belongs to to practice the present invention. Various modifications of the above-described embodiment can naturally be made by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Accordingly, the present invention is not limited to the described embodiments, but is to be construed in the broadest scope in accordance with the technical concept defined by the claims.

DESCRIPTION OF SYMBOLS 1 hopper 2 hopper box 3 passage hole 5 rotating drum 6 drum axis 7 cylinder 8 stirring rod 10 powder stirring mechanism 11 first stirring impeller 12 shaft 14 stirring paddle 21 second stirring impeller 22 shaft 24 stirring paddle 31 first Gear 32 Second gear 35 First sprocket 36 Second sprocket 38 Chain 40 Baffle plate 42 Screw conveyor 45 Third gear 46 Support member 47 Powder stopper 50 Object 51 Screen 53 Sponge roller 54 Motor 60 Mesh 62 Mounting table 65 Motor O1 , O2, O3 Axis of rotation

Claims (11)

A hopper box having a bottom with a through hole through which powder can pass;
A rotating drum disposed within the hopper box and pushing powder in the hopper box out of the hopper box through the through holes;
A hopper, which is disposed in the hopper box, and has a powder stirring mechanism which causes the powder in the hopper box to circulate. The powder stirring mechanism is
A first stirring impeller disposed in the hopper box and located higher than the rotating drum;
A second stirring impeller disposed in the hopper box and positioned higher than the first stirring impeller;
The hopper according to claim 1, further comprising: a rotating device configured to rotate the first stirring impeller and the second stirring impeller in the direction opposite to the rotation direction of the rotating drum.   The hopper according to claim 2, wherein a rotation axis of the first stirring impeller is located downstream of a top of the rotary drum in a rotation direction of the rotary drum.   The rotary shaft center of the second stirring impeller is located between the rotary shaft center of the rotary drum and the rotary shaft center of the first stirring impeller when viewed from above the hopper box. The hopper according to claim 3, characterized in that   The hopper according to any one of claims 2 to 4, wherein the rotating device rotates the first stirring impeller and the second stirring impeller at a speed higher than that of the rotating drum.   The hopper according to any one of claims 1 to 5, wherein the hopper box has a rectangular horizontal cross section.   The hopper according to any one of claims 1 to 6, wherein a rotation axis of the rotary drum is parallel to a bottom of the hopper box. The hopper further comprises a baffle plate disposed in the hopper box,
The hopper according to any one of claims 1 to 7, wherein an edge of the baffle plate is disposed in contact with or in proximity to an outer peripheral surface of the rotary drum. The hopper further comprises a screw conveyor disposed in the hopper box,
9. The screw conveyor according to claim 1, wherein the screw conveyor is adjacent to a lower portion of the rotating drum and located upstream of a lowermost portion of the rotating drum in a rotation direction of the rotating drum. Hopper described in any one of the items. The hopper further comprises a powder stopper in contact with or in proximity to the lower portion of the rotating drum,
10. The powder stopper according to claim 1, wherein the powder stopper is fixed to the bottom of the rotary drum, and is located upstream of the lowermost portion of the rotary drum in the rotation direction of the rotary drum. The hopper according to any one of the preceding claims. An electrostatic screen printing apparatus for adhering powder to an object by electrostatic force, comprising:
A screen having a mesh of a predetermined shape;
A sponge roller rubbing the powder into the screen;
An electric motor for rotating the sponge roller about its axis;
A hopper for feeding the powder onto the sponge roller;
A power supply for applying a voltage between the screen and the object;
An electrostatic screen printing apparatus, wherein the hopper is the hopper according to any one of claims 1 to 10.

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