JP2003175580A - Electrostatic printing system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic printing system which can continuously perform a uniform and beautiful printing, and also, wherein the waste of a powder ink is less. <P>SOLUTION: The powder ink is rubbed into a screen 110 on which a specified printing pattern is formed. At the same time, the powder ink is adhered to an article 1 to be printed by applying a voltage in a space between the screen 110 and the article 1 to be printed by this electrostatic printing system. Such an electrostatic printing system is equipped with a carrying conveyor 108 which carries the article 1 to be printed, a screen-moving mechanism, and a synchronizing mechanism. In this case, the screen-moving mechanism moves a plurality of screens 110 on the top of the article 1 to be printed which is moved by the carrying conveyor 108. The synchronizing mechanism synchronizes the moving speed of the article 1 to be printed by the carrying conveyor 108 and the moving speed of the screens 110 by the screen-moving mechanism. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic printing apparatus, and in particular, electrostatic force is used to attach powder ink to the surface of a printed material to form a printing pattern such as characters and figures on the surface of the printed material. The present invention relates to an electrostatic printing device that prints.

[0002]

2. Description of the Related Art Heretofore, an electrostatic printing apparatus has been known in which a powder ink is attached to the surface of an object to be printed by using electrostatic force to print a printing pattern such as characters and figures on the surface of the object to be printed. . FIG. 9 is a schematic diagram showing the configuration of this type of electrostatic printing apparatus. The conventional electrostatic printing apparatus includes a stencil screen 510 arranged above the substrate 500, a rotating brush 520 on the screen 510, and the powder ink 53.
And a hopper 540 for supplying 0 to the brush 520. A print pattern such as characters and figures is formed on the screen by a mesh network 511.

Powder ink 5 supplied from hopper 540
30 rotates the screen 510 by rotating the brush 520.
Is pushed downward from the mesh net 511. A high DC voltage is applied between the material to be printed 500 and the screen 510 by a DC power supply DC, and an electrostatic field is formed between the material to be printed 500 and the screen 510. The charged powder ink that has passed through the mesh net 511 travels straight in the electrostatic field toward the printed material 500, which is the counter electrode, and adheres to the surface of the printed material 500. In this way, the printing pattern such as characters and figures on the screen 510 is printed on the printing object 50.
Printed on surface 0.

[0004]

However, in the conventional electrostatic printing apparatus, when printing is continuously performed on a plurality of printing materials, the printing material 500 is placed under the screen 510 for each printing material. Must be placed before printing. Therefore, the processing time until printing becomes long and the printing also takes time. As described above, in the conventional electrostatic printing apparatus, continuous printing is not practically performed at present.

The present invention has been made in view of the above problems of the prior art, and provides an electrostatic printing apparatus capable of continuously performing uniform and clean printing and less waste of powder ink. The purpose is to provide.

[0006]

In order to solve the problems in the prior art, the first aspect of the present invention is
An electrostatic printing device that rubs the powder ink onto a screen on which a predetermined printing pattern is formed and applies the voltage between the screen and the print object to adhere the powder ink to the print object. A conveyer that conveys the printed matter, a screen moving mechanism that moves a plurality of screens above the printed matter that is moved by the conveyer, a moving speed of the printed matter by the conveyer, and the screen moving mechanism described above. The electrostatic printing apparatus is provided with a synchronizing mechanism that synchronizes the moving speed of the screen.

According to the above-mentioned structure, since electrostatic printing can be continuously performed, the printing speed becomes extremely high and the printing efficiency can be improved. Further, it is possible to provide an electrostatic printing device that is small and lightweight with a simple configuration at low cost. In addition, it is not necessary to stop the operation of the device for cleaning the screen, and the operating rate can be improved.

According to a preferred aspect of the present invention, a height detection sensor for detecting the height of the material to be printed on the conveyor on the upstream side of the printing position, and based on the detection result of the height detection sensor, It is characterized in that it is provided with a lifter for moving the above-mentioned transfer conveyor up and down according to the height of the printed matter.

The distance between the surface to be printed of the material to be printed and the screen (printing distance) is the minimum distance between the material to be printed and the screen, which is ideal for clear printing. is there. Since the height of the printed material varies depending on each printed material, if the distance between the conveyor and the screen is constant, it is not possible to obtain the optimum printing distance for each printed material. Therefore, the height detection sensor detects the height of each printed material, and the lifter rise distance is adjusted based on the output from this height detection sensor to print according to the height of each printed material. By optimizing the distance, it is possible to perform clear and beautiful printing even if the heights of the respective print substrates are different.

A preferred aspect of the present invention comprises a screen unit having a flat plate having an opening for arranging the screen, and a side piece attached to an upper surface of one side portion of the flat plate. , A sandwiching portion that sandwiches the screen disposed in the opening portion, and a protruding portion that protrudes from one side portion of the flat plate, the length of the protruding portion of the side piece,
It is characterized in that it is longer than the distance from the other side of the flat plate to the opening.

With such a structure, when the two screen units are adjacent to each other, the protrusion of the other screen unit is located above the opening of the other screen unit. At this time, the screen is constrained by both the sandwiching portion of the side piece of the screen unit and the protruding portion of the side plate of the rear screen unit, and the screen does not move. Therefore, by printing the two screen units adjacent to each other, it is possible to perform accurate printing at an accurate position. Further, if the two screen units are adjacent to each other for cleaning the screen, the work becomes easier and it is effective.

In this case, it is preferable to bend the corner of the side piece upward. When the two screen units are adjacent to each other, one screen unit is adjacent to the other screen unit while gradually increasing the contact area. At this time, since the screen units start contacting at the corners, by bending the corners upward, the resistance at the time of contact can be reduced and the screen units can be smoothly adjacent to each other.

In a preferred aspect of the present invention, a cylindrical screen brush for rubbing the powder ink onto the screen, and the powder ink from a position on the rotation direction side of the screen brush above the center of the screen brush. And a hopper that supplies the screen brush to the screen brush.

When the powder ink is sprayed on the screen brush, the powder ink dispersed by the agglomeration of the powders becomes non-uniform, but when the powder ink is sprayed from directly above the screen brush, The non-uniform powder ink scattered on the brush may be rubbed on the screen as it is, so that the powder ink adhered to the printing material may have a shade. According to the above configuration, the powder ink is supplied from a position deviated from the position right above the center of the screen brush in the rotational direction, so that such a problem is solved. That is, even if the powder ink sprayed on the screen brush is uneven, it is sprayed at a position deviated from the position right above the center of the screen brush in the direction of rotation. It hits a large outer peripheral surface, is crushed into pieces by the momentum of the rotation of the screen brush, diffuses, and falls on the screen before the rubbing position (before the printing position). For this reason, the powder ink can be rubbed uniformly on the screen, and uniform and beautiful printing can be performed.

A preferred aspect of the present invention is a screen brush for rubbing the powder ink onto the screen, and an object to be printed for detecting whether or not the object to be printed is placed on the conveyer conveyor upstream of the printing position. When it is determined that the printing object is placed on the conveyor based on the detection result of the detection sensor and the printing object detection sensor,
It further comprises a brush separating mechanism for separating the screen brush from the screen when the material to be printed on the transport conveyor is located at the printing position.

If the powder ink is rubbed into the screen when the print object is not in the printing position, the powder ink is scattered below the screen, and the transport conveyor for transferring the print object and the surroundings of the machine are not only soiled. Instead, the powder ink is wasted. In addition, when a material to be printed is placed on the conveyor after being contaminated with the powder ink, the bottom surface of the material to be printed becomes dirty. According to the above configuration, the powder ink is not rubbed into the screen by moving the screen brush away from the screen when the material to be printed is not placed on the conveyor. Therefore, it is possible to prevent the powder conveyor from being contaminated by the powder ink and the waste of the powder ink.

In a preferred aspect of the present invention, an abutting piece that abuts the upper surface and / or the lower surface of the screen moved by the screen moving mechanism after printing is performed, and the powder scraped by the abutting piece. It is characterized by further comprising an ink recovery device having a recovery box for recovering ink.

As a method of recovering the powder ink not used for printing, there is a method of sucking the powder ink by vacuum. In this method, dust in the air is also sucked together with the powder ink, and it is recovered. Powder ink cannot be reused and must be discarded. About 30% of the whole powder ink is not used for printing, and thus a large amount of powder ink is wasted by the vacuum method. According to the above-described ink recovery device, it is possible to easily recover only the powder ink, and since the recovered powder ink does not contain impurities such as dust, it can be reused. Therefore, the running cost of the device can be reduced.

In a second aspect of the present invention, the powder ink is rubbed on a screen on which a predetermined print pattern is formed, and a voltage is applied between the screen and the material to be printed, thereby the powder ink is formed. An electrostatic printing device for adhering to a material to be printed, comprising: a cylindrical screen brush that rubs powder ink onto the screen; and a screen brush drive mechanism that rotates the screen brush and simultaneously moves the screen brush in the axial direction. It is an electrostatic printing device characterized by the above.

Depending on the printing pattern of the screen, the amount of powder ink consumed may vary depending on the position on the screen, but by moving the screen brush in the axial direction and rubbing the powder ink, the amount of powder ink is changed depending on the position on the screen. Even if the consumption amount of the body ink is different, it is possible to diffuse the powder ink on the screen as a whole. Therefore, it is possible to make the amount of ink on the screen uniform and perform uniform and beautiful printing without performing complicated ink amount control. Particularly, since the screen brush can be rotated and moved in the axial direction by one driving source, the mechanism can be simplified and the manufacturing cost can be reduced. Moreover, since electrical control is only required for one system, the electric circuit for control is simplified and the manufacturing cost can be reduced.

In a third aspect of the present invention, the powder ink is rubbed on a screen on which a predetermined printing pattern is formed, and a voltage is applied between the screen and the material to be printed to obtain the powder ink. An electrostatic printing device for adhering to a printing object, wherein a plurality of heating fins arranged alternately, a heater for heating the heating fins, and a temperature sensor for detecting and controlling the temperature of the heaters are heated. And a spray plate having a slit formed to spray the high temperature steam onto the printing object, and the steam introduced from the steam inlet is brought into contact with the heating fins to generate steam at a temperature necessary for fixing the printing object. An electrostatic printing device comprising a device.

When the powder ink adhered to the surface of the material to be printed is fixed with steam, and the temperature of the surface of the material to be printed is low, the temperature of the steam hitting the surface of the material to be printed decreases and condensation occurs. I will end up. If the vapor condenses more than necessary in this way, the surface of the material to be printed gets wet with water and the printed powder ink is washed away before the fixing, so that the fixing cannot be performed properly.
In order to prevent this, it is necessary to spray high-temperature steam onto the surface of the printed material in a short time (2 to 5 seconds) so that the powder ink is not flowed onto the surface of the printed material and can be fixed neatly. Moisture and temperature need to be given. According to the above configuration,
Since high-temperature steam at the temperature necessary for fixing the powder ink can be instantaneously and continuously jetted from the slits of the jet plate, the powder ink does not flow due to moisture, and the powder ink is completely fixed and is beautiful. Printing can be performed.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of an electrostatic printing apparatus according to the present invention will be described in detail with reference to FIGS. FIG. 1 is a plan view showing the outline of an electrostatic printing apparatus according to an embodiment of the present invention, and FIG. 2 is a front view of FIG.

As shown in FIGS. 1 and 2, the electrostatic printing apparatus according to the present embodiment has a printing section 10 for adhering powder ink onto the surface of a material 1 to be printed such as confectionery and bread, and the surface of the material 1 to be printed. Fixing unit 2 for fixing the powder ink attached to the
0 and a control unit 30 that controls each unit. The material to be printed 1 is not limited to food such as confectionery, but may be an industrial product. Further, as the powder ink, edible ink containing a natural pigment or a synthetic pigment, cocoa powder, wheat flour,
Various powders such as matcha powder, sugar powder or industrial powder ink can be used depending on the application.

The printing unit 10 includes a plurality of flat screen-shaped screen units 100 and the screen unit 1 at the printing position.
00-shaped cylindrical screen brush 10
2, a hopper 104 arranged above the screen brush 102, and a transport pallet 10 on which the material 1 to be printed is placed.
6 is provided.
In addition, the fixing unit 20 has a conveyer conveyor 200 that conveys the object to be printed 1 to which the powder ink is attached in the printing unit 10.
And a fixing device 210 for fixing the powder ink adhered to the material to be printed 1 are provided.

The screen unit 100 of the printing unit 10 includes a stencil screen 110 made of a conductive material.
The screen 110 has a print pattern such as characters and figures formed on a mesh screen. In this embodiment, eight screen units 10
0 is provided in the printing unit 10. The hopper 104 supplies the powder ink to the screen brush 102, and the screen brush 102 rubs the powder ink supplied from the hopper 104 onto the screen 110 in the screen unit 100.

The object to be printed 1 placed on the transfer pallet 106 is transferred to the printing position by the transfer conveyor 108,
At this time, the screen 11 in the screen unit 100
0 and the transfer pallet 106 have a high DC voltage, for example, 5
000-6000V high voltage is applied to the screen 1
An electrostatic field is formed between 10 and the transfer pallet 106.
Then, the powder ink is rubbed against the screen 110 by the screen brush 102, and the charged powder ink passing through the mesh net is accelerated toward the transfer pallet 106, which is the counter electrode, by the electrostatic field, and the transfer pallet 10 is transferred.
6 is attached to the substrate 1 to be printed. The substrate 1 to which the powder ink is attached is sent from the conveyor 108 of the printing unit 10 to the conveyor 200 of the fixing unit 20 and passes through the inside of the fixing device 210 of the fixing unit 20. In the fixing device 210, the material to be printed 1 is heated by the high temperature steam, and the powder ink adhered to the surface of the material to be printed 1 is fixed by this heating.

A plurality of transfer pallets 106 that are continuous in the transfer direction are attached to the transfer conveyor 108 of the printing unit 10, and the object 1 to be printed is placed on the transfer pallets 106. A drive motor 112 is installed below the transfer conveyor 108, and an output shaft 112a of the drive motor 112 is connected to a drive shaft 114 of the transfer conveyor 108 via a miter gear (not shown).

Further, each screen unit 100 of the printing section 10 is attached to a carrier chain 118 which is bridged between two sprockets 116a and 116b.
One sprocket 116a is connected to the driven shaft 120 via a miter gear (not shown). Sprockets 122a and 122b are attached to the driven shaft 120 and the drive shaft 114 of the conveyor 108, respectively, and a chain 124 is stretched between these sprockets 122a and 122b.

When the drive motor 112 described above is driven,
The rotation of the drive motor 112 is transmitted to the drive shaft 114 of the conveyor 108 and also to the sprockets 122a and 116a via the chain 124 connected to the sprocket 122b of the drive shaft 114. Therefore, the rotation of the drive motor 112 causes the conveyor 10 to rotate.
8 is driven, the sprocket 116a rotates and the screen unit 100 moves in an elliptical orbit as shown in FIG. As described above, in the present embodiment, the drive motor 112, the drive shaft 114, and the sprocket 116.
a, 116b, 122a, 122b, chain 118,
The screen moving mechanism configured to move the screen 110 above the object to be printed 1 moved by the conveyor 108 is constituted by the driven shaft 120 and the driven shaft 120.

Here, the drive shaft 11 of the transfer conveyor 108
4 and the rotation of the sprocket 116a are synchronized, and the moving speed of the transfer pallet 106 by the transfer conveyor 108 and the moving speed of the screen unit 100 are the same. As described above, in the present embodiment, the screen moving mechanism and the transfer conveyor 10 described above are used.
8 configures a synchronization mechanism that synchronizes the moving speed of the printing target 1 by the conveyor 108 and the moving speed of the screen 110 by the screen moving mechanism. In this case, the printing target 1 by the transport conveyor 108
Screen 11 by moving speed and screen moving mechanism
It is also possible to synchronize while adjusting the ratio with the moving speed of 0. By doing so, the pattern printed on the substrate 1 can be expanded and contracted in the moving direction.

As described above, each screen unit 1
00 moves while drawing an elliptical orbit, but as shown in FIG. 1, when the screen unit 100 is at the printing position, it is adjacent to the screen units 100 before and after it. After printing is performed at the printing position, the screen unit 100 separates from the front and rear screen units (hereinafter, this position is referred to as a first intermediate position), and again, the position opposite to the printing position (hereinafter, referred to as a working position). It is adjacent to the front and rear screen units. After that, the screen unit 100 separates from the front and rear screen units (hereinafter, this position is referred to as a second intermediate position) and again adjoins the front and rear screen units at the printing position.

Upstream of the printing position, that is, the conveyor 1
On the upstream side in the traveling direction of 08, a print object detection sensor 126 is arranged with the transport pallet 106 located above the transport conveyor 108 in between. As the printed material detection sensor 126, an optical sensor including a light projecting portion 126a and a light receiving portion 126b is used. As shown in FIG. 1, each transport pallet 106 is formed with a light passing hole 106a for passing the light emitted from the light projecting portion 126a of the optical sensor. When the material to be printed 1 is not placed on the transport pallet 106, the light emitted from the light projecting unit 126a passes through the light passing hole 106a of the transport pallet 106 and is received by the light receiving unit 126b. It is detected that the print substrate 1 is not placed on the top. On the other hand, when the print target 1 is placed on the transport pallet 106, the light from the light projecting unit 126a is blocked by the print target 1 on the transport pallet 106 and does not reach the light receiving unit 126b. It is detected that the substrate 1 is placed on the print medium 106. The output signal of the printing material detection sensor 126 is sent to the control unit 30.

Further, on the upstream side of the printing position, there is also provided a height detecting sensor 128 for detecting the height of the printing object 1 placed on the transport pallet 106, and this height detecting sensor 128 is also described above. Like the printed material detection sensor 126, it is composed of an optical sensor. The output signal of the height detection sensor 128 is also sent to the control unit 30.

At the printing position, a lifter 130 for moving the carrying rail of the carrying conveyor 108 up and down is provided.
When the transport rail is lifted up by the lifter 130, the transport pallet 106 of the transport conveyor 108 is also lifted. The distance between the surface to be printed of the material to be printed 1 and the screen 110 (hereinafter referred to as the printing distance).
Is ideal for clear printing by setting the minimum distance between the substrate 1 and the screen 110 so that no discharge occurs. Since the height of the substrate 1 varies depending on each substrate 1, when the distance between the transport pallet 106 and the screen 110 is fixed to be constant, an optimum printing distance can be obtained for each substrate 1. Can not. Therefore, in the present embodiment, the height detection sensor 128 described above detects the height of each print substrate 1, and the lift distance of the lifter 130 is adjusted based on the output from the height detection sensor 128. The printing distance is optimized according to the height of the printing target 1. As described above, according to the electrostatic printing apparatus of the present invention, it is possible to perform clear and beautiful printing even when the heights of the respective print substrates 1 are different.

FIG. 3A is a perspective view showing the screen unit 100 with the screen 110 removed.
3B is a front sectional view of FIG. 3A, and FIG. 3C is a sectional view of the screen unit 100 at the printing position. The screen unit 100 in this embodiment is
As shown in FIGS. 3A and 3B, a flat plate 134 on which a rectangular opening 132 is formed, and a side piece 136 attached to a side surface of the flat plate 134 on the screen unit moving direction side. , And a mounting plate 138 attached to the transport chain 118. A screen support 140 that supports the screen 110 is provided below the opening 132 of the flat plate 134.

The side piece 136, as shown in FIG.
The flat plate 1 extends from above the screen support portion 140 of the flat plate 134 in the moving direction of the screen unit 100 and is located above the screen support portion 140.
And a projecting part 144 projecting from the side part of the device.
The screen 110 is arranged in the opening 132 of the flat plate 134 with one end thereof being sandwiched between the screen support portion 140 of the flat plate 134 and the sandwiching portion 142 of the side piece 136.

As shown in FIG. 3B, the length L1 of the projecting portion 144 of the side piece 136 is the opening 132 from the other side portion.
Is longer than the length L2. Therefore, when the two screen units are adjacent to each other, the protrusion 144 of the rear screen unit is located above the opening 132 of the front screen unit. With such a configuration, when the screen unit 100b reaches the printing position as shown in FIG. 3C, the screen 110b has a holding portion 142b of the screen unit 100b and a protruding portion 144a of the rear screen unit 100a. It will be restrained by both sides, and when rubbing the screen brush 102, the screen 110b.
Since it does not move, accurate printing can be performed at an accurate position. Similarly, since the screen 110 does not move inside the screen unit 100 even at the work position, cleaning the screen 110 or the like at the work position facilitates work and is effective.

Further, as shown in FIG. 3A, the side piece 13
The corner portion 146 of the No. 6 on the side of the mounting plate 138 is bent upward. When the screen unit 100 moves from the second intermediate position to the print position or from the first intermediate position to the working position while the screen unit 100 moves while drawing an elliptical orbit, the screen unit 100 on the front side is moved.
While gradually increasing the contact area, it finally adjoins the front screen unit 100 at the printing position or the working position. At this time, the screen unit 100 starts to come into contact with the screen unit 100 on the front side from the above-mentioned corner portion 146. Therefore, by bending this corner portion 146 upward, the resistance at the time of contact is reduced and the screen unit 10 is reduced.
0s can be smoothly adjacent to each other.

FIG. 4 is a front sectional view around the printing position of the printing unit 10 shown in FIG. 1, and FIG. 5 is a side sectional view. As shown in FIGS. 4 and 5, the hopper 104 includes a hopper container 150 for containing powder ink, a hopper brush 152 provided inside the hopper container 150, and a hopper container supporting portion 156 attached to the fixed frame 154. It has and. The powder ink supplied to the screen brush 102 is put in from above the hopper container 150. The bottom surface of the hopper container 150 and the hopper container supporting portion 156 are provided with spray holes 157 for spraying the supplied powder ink onto the screen brush 102. Further, the fixed frame 154 is provided with a hopper brush rotation motor 158 for rotating the hopper brush 152, and the rotation shaft 152a of the hopper brush 152 is connected to the hopper brush rotation motor 158. By rotating the hopper brush 152 by driving the hopper brush rotation motor 158, the powder ink introduced into the hopper container 150 is sprayed onto the screen brush 102 through the spray holes 157.

As shown in FIG. 4, the above-mentioned spray hole 157 is not located directly above the center of the screen brush 102, but is located at a position displaced from the position directly above the center of the screen brush 102 in the direction of rotation. Has been done. When the powder ink is sprayed onto the screen brush 102, the powder ink dispersed due to the agglomeration of the powder particles becomes non-uniform, but when the powder ink is sprayed from directly above the screen brush 102, The non-uniform powder ink sprinkled on the 102 may be rubbed on the screen 110 as it is, so that the powder ink adhering to the material to be printed 1 may be shaded. In the present embodiment, as described above, since the powder ink is supplied from the position deviated from the position right above the center of the screen brush 102 in the rotation direction side, such a problem is solved. That is, even if the powder ink dispersed on the screen brush 102 is uneven, the screen brush 1
The powder ink dropped from the spray holes 157 hits the outer peripheral surface of the screen brush 102 with a large inclination angle, because the powder ink is sprayed at a position deviated from the position right above the center of 02 in the direction of rotation. Are crushed into pieces and diffused, and fall on the screen 110 in front of the rubbing position (in front of the printing position). Therefore, the powder ink can be rubbed uniformly on the screen 110, and uniform and beautiful printing can be performed.

As shown in FIG. 5, the fixed frame 154 has a movable frame 1 rotatable about a support shaft 160.
62 is attached. The screen brush 102 described above is attached to the lower portion of the movable frame 162. The screen brush 102 is a urethane sponge 1
64, a slide cylinder 166 to which the urethane sponge 164 is attached, and a spline shaft 168 arranged inside the slide cylinder 166. In the state shown in FIG. 5, the urethane sponge 1 of the screen brush 102
64 is in contact with the screen 110. The slide cylinder 166 is slidable in the axial direction of the spline shaft 168 via a bearing, and a key (not shown) provided on the slide cylinder 166 and a key groove (formed in the spline shaft 168). Spline shaft 1 by engaging with (not shown)
It is rotatable with 68.

Spline shaft 1 of screen brush 102
68 is attached to the movable frame 162, and a sprocket 170 is provided at the end of the spline shaft 168. A screen brush rotation motor 172 for rotating the screen brush 102 is provided above the movable frame 162, and the screen brush rotation motor 172 is connected to the sprocket 170 of the spline shaft 168 via a chain 174. .
By driving the screen brush rotation motor 172, the spline shaft 168 of the screen brush 102 is rotated.

Slide cylinder 1 of screen brush 102
A cam 176 fixed to the movable frame 162 is provided at 66.
Is formed with a cam groove 178. Therefore, when the spline shaft 168 is rotated by driving the screen brush rotation motor 172, the slide cylinder 166 is rotated together with the spline shaft 168, and the engagement of the cam 176 causes the slide cylinder 166 to reciprocate in the axial direction. Thus, in this embodiment, the slide cylinder 16
6, spline shaft 168, sprocket 170, screen brush rotation motor 172, chain 174, cam 1
The screen brush drive mechanism is configured by 76 to rotate the screen brush 102 and simultaneously move the screen brush 102 in the axial direction.

Depending on the printing pattern of the screen 110, the amount of powder ink consumed may differ depending on the position on the screen 110. As described above, the screen brush 102 is also moved in the axial direction to perform rubbing. Even if the amount of powder ink consumed varies depending on the position on the screen 110, the powder ink on the screen 110 can be diffused as a whole. Therefore, the screen 1 can be used without complicated ink amount control.
It is possible to make the amount of ink on 10 uniform and perform uniform and beautiful printing. Particularly, in the present embodiment, since the screen brush 102 can be rotated and moved in the axial direction with only one motor, the mechanism can be simplified and the manufacturing cost can be reduced. Moreover, since electrical control is only required for one system, the electric circuit for control is simplified and the manufacturing cost can be reduced. In addition, it is preferable that the width W of movement in the axial direction is such a width as to reach from a position where the powder ink consumption amount is small to a position where the powder ink consumption amount is large.

As shown in FIG. 5, an air cylinder 180 is provided above the movable frame 162, and the tip of the rod 180a of the air cylinder 180 is hinged to the fixed frame 154. This air cylinder 1
80 operates based on the output from the printing material detection sensor 126 described above. That is, when the printing target 1 is not placed on the transport pallet 106 transported to the printing position, the air cylinder 180 operates, the rod 180 a of the air cylinder 180 extends, and the movable frame 162 supports the support shaft 16.
It rotates about 0 and becomes the state shown in FIG. At this time, the urethane sponge 164 of the screen brush 102
Is located above the state shown in FIG. 5, and is separated from the screen 110. As described above, in the present embodiment, the screen brush 102 is attached to the screen 11 by the movable frame 162, the support shaft 160, and the air cylinder 180.
A brush separating mechanism that separates from 0 is configured.

Here, if the powder ink is rubbed against the screen 110 when the object to be printed 1 is not in the printing position, the powder ink is scattered below the screen 110,
Not only does the transport pallet 106 that transports the material to be printed 1 and the surroundings of the machine become dirty, but the powder ink is wastefully consumed. Further, when the object 1 to be printed is placed on the transport pallet 106 after being soiled with the powder ink in this way, the object 1 to be printed is
The bottom of the will get dirty. In the present embodiment, when the printing object 1 is not placed on the transfer pallet 106 that has been transferred to the printing position, the urethane sponge 164 of the screen brush 102 is moved away from the screen 110, so that the powder ink rubs against the screen 110. Never be Therefore, it is possible to prevent the transport pallet 106 and the periphery of the machine from being contaminated with the powder ink, and to eliminate the waste of the powder ink. It is preferable to stop the driving of the hopper brush rotation motor 158 at the same time as the operation of the air cylinder 180 to stop the supply of the powder ink from the hopper 104 to the screen brush 102.

In the present embodiment, the powder ink is rubbed into the screen 110 by a single screen brush 102 without providing a plurality of screen brushes 102. A plurality of screen brushes 102 may be used in order to rub a large amount of powder ink on the screen 110 in a short time. In this case, the positional relationship between the screen brush 102, the screen 110, and the substrate 1 is different. If they do not match on the screen brush 102, printing misalignment will occur. Screen brush 1 according to the present embodiment
In No. 02, since a brush having a large diameter is used, a required amount of powder ink can be rubbed with one brush, so that printing deviation can be prevented and clean printing can be performed.

As shown in FIG. 1, at the first intermediate position of the printing unit 10, an ink collecting device 182 for collecting the powder ink not used for printing from the screen unit 100 after printing is installed. FIG. 7 is a vertical cross-sectional view of the ink recovery device 182 shown in FIG. As shown in FIG.
The ink collecting device 182 includes a carry-in port 184a for carrying in the screen unit 100 and a carry-out port 184 for carrying out the screen unit 100.
and a plurality of rubber plates (contact pieces) 186 that come into contact with the upper and lower surfaces of the moving screen unit 100 are arranged inside the collection box 184. Screen unit 10
0 is introduced into the inside of the collection box 184 from the carry-in port 184a of the collection box 184, the upper and lower surfaces thereof contact the inner rubber plate 186, and the powder ink not used for printing is scraped up by the rubber plate 186. After passing through the screen unit 100, it falls to the bottom of the collection box 184. The powder ink collected at the bottom of the collection box 184 can be taken out from a not-shown outlet and reused.

As a method of recovering the powder ink not used for printing, there is a method of sucking the powder ink by vacuum. In this method, dust in the air is also sucked together with the powder ink, and it is recovered. Powder ink cannot be reused and must be discarded. About 30% of the whole powder ink is not used for printing, and thus a large amount of powder ink is wasted by the vacuum method. In the present embodiment, by providing the ink recovery device as described above, it is possible to easily recover only the powder ink, and the recovered powder ink does not contain impurities such as dust. Can be reused. Therefore, the running cost of the device can be reduced.

Next, the fixing device 210 in this embodiment.
Will be described in detail. FIG. 8 is a vertical sectional view showing the fixing device 210. As shown in FIG. 8, the fixing device 210
Is a heater 212 embedded in the side wall, a pair of heating portions 216a and 216b having a plurality of heating fins 214,
The temperature sensor 218 for detecting the temperature of the heater 212 is provided. A vapor inlet 220 for introducing vapor at 100 ° C., for example, is formed in the upper part of the fixing device 210, and the vapor inlet 220 is connected to a vapor source (not shown).
An ejection plate 224 having a plurality of slits 222 formed therein is disposed below the fixing device 210. The pair of heating units 216a and 216b are arranged such that the respective heating fins 214 are alternately positioned, and thus a meandering flow path 226 is formed between the heating units 216a and 216b.

The steam introduced from the steam inlet 220 is
The steam flows in the meandering flow path 226 between the heating units 216a and 216b while being in contact with the heating fins 214 heated by the heater 212, and becomes high-temperature steam of, for example, 400 ° C. in a short time. This high-temperature steam is jetted from the slit 222 of the jet plate 224 onto the surface of the printing target 1. Heating unit 216a, 21
Since the heating fins 214 of 6b are alternately arranged,
The contact area between the heating fins 214 and the steam becomes large, and the temperature of the steam can be reliably raised in a short time. At this time, the temperature of the heater 212 is controlled by the temperature sensor 218 to generate steam at a temperature necessary for fixing the print substrate 1. It is necessary to set the temperature of the steam to be jetted according to the specific heat and surface temperature of the material to be printed 1. For example, those with a small specific heat such as steamed buns are about 120 ° C, and those with a large specific heat such as tamagoyaki are about 400 Use high temperature steam at ℃.

When the powder ink adhered to the surface of the material to be printed is fixed by steam and the temperature of the surface of the material to be printed is low, the temperature of the steam hit the surface of the material to be printed decreases and condensation occurs. I will end up. If the vapor condenses more than necessary in this way, the surface of the material to be printed gets wet with water and the printed powder ink is washed away before the fixing, so that the fixing cannot be performed properly.
In order to prevent this, it is necessary to spray high-temperature steam onto the surface of the printed material in a short time (2 to 5 seconds) so that the powder ink is not flowed onto the surface of the printed material and can be fixed neatly. Moisture and temperature need to be given.

In order to fix the powder ink adhered to the material to be printed 1 with steam, it is necessary that the powder ink absorbs moisture by the steam and gels. When heat of 80 ° C. or higher is applied to the gelled powder ink, the powder ink is subsequently cured and fixed on the surface. At this time, like the powder ink, the surface of the printing material 1 must be at a temperature of 80 ° C. or higher, or the powder ink will not be completely fixed. According to the present embodiment, since the high-temperature steam having a temperature necessary for fixing the powder ink can be instantaneously and continuously jetted from the slit 222 of the jet plate 224, the powder ink does not flow due to moisture, and the powder ink does not flow. Can be completely fixed to perform beautiful printing.

As described above, the screen unit 10
0 is the object to be printed 1 conveyed by the conveyor 108
It moves in an elliptical orbit synchronously with. When the screen unit 100 reaches the printing position, the screen brush 10
The powder ink is rubbed against the screen 110 in the screen unit 100 by 2 and the powder ink is attached to the surface of the printing target 1 for printing. The screen unit 100 after printing is introduced into the ink collecting device 182 arranged at the first intermediate position, and the powder ink remaining on the upper and lower surfaces of the screen unit 100 is collected here.
After that, the screen unit 100 is moved to the print position again after passing through the work position and the second intermediate position, and the above-described print processing is performed here. Such a series of processes is continuously repeated. A cleaning device may be provided at the second intermediate position to suck the powder ink firmly adhered to the upper and lower surfaces of the screen unit 100 by vacuum.

As described above, according to the present invention, since electrostatic printing can be continuously performed, the printing speed becomes extremely high and the printing efficiency can be improved. Further, it is possible to provide an electrostatic printing device that is small and lightweight with a simple configuration at low cost. Also, in the working position, the screen 110
Therefore, it is not necessary to stop the operation of the device for cleaning the screen 110, and the operating rate can be improved.

In the above-described embodiment, an example in which the plurality of screen units 100 move while drawing an elliptical orbit in the horizontal plane has been described, but the present invention is not limited to this. For example, the plurality of screen units 100 may be moved up and down.

Although one embodiment of the present invention has been described so far, it is needless to say that the present invention is not limited to the above embodiment and may be implemented in various different forms within the scope of the technical idea thereof.

[0059]

As described above, according to the present invention, electrostatic printing can be continuously performed, so that the printing speed is extremely high and the printing efficiency can be improved. Further, it is possible to provide an electrostatic printing device that is small and lightweight with a simple configuration at low cost. In addition, it is not necessary to stop the operation of the device for cleaning the screen, and the operating rate can be improved.

[Brief description of drawings]

FIG. 1 is a plan view schematically showing an electrostatic printing device according to an embodiment of the present invention.

FIG. 2 is a front view of FIG.

3 (a) is a perspective view showing a screen unit according to an embodiment of the present invention, and FIG. 3 (b) is FIG. 3 (a).
FIG. 3C is a sectional view showing the screen unit at the printing position.

FIG. 4 is a front sectional view around a printing position of the printing unit shown in FIG.

5 is a side cross-sectional view around the printing position of the printing unit shown in FIG.

FIG. 6 is a diagram showing a state in which the screen brush shown in FIG. 5 has moved upward.

7 is a vertical cross-sectional view of the ink recovery device shown in FIG.

FIG. 8 is a vertical sectional view of the fixing device shown in FIG.

FIG. 9 is a schematic view showing a conventional electrostatic printing apparatus.

[Explanation of symbols]

1 Printed material 10 Printing section 20 Fixing section 30 Control section 100 Screen unit 102 Screen brush 104 Hopper 106 Conveying pallet 108, 200 Conveying conveyor 110 Stencil screen 112 Driving motor 114 Driving shafts 116a, 116b, 122a, 122b, 170
Sprocket 118, 124, 174 Transport chain 120 Driven shaft 126 Printed object detection sensor 128 Height detection sensor 130 Lifter 132 Opening part 134 Flat plate 136 Side piece 138 Mounting plate 140 Screen support part 142 Clamping part 144 Projection part 146 Corner part 150 Hopper container 152 Hopper Brush 154 Fixed Frame 156 Hopper Container Support 157 Dispersion Hole 158 Hopper Brush Rotating Motor 160 Spindle 162 Movable Frame 164 Urethane Sponge 166 Slide Cylindrical Body 168 Spline Shaft 172 Screen Brush Rotating Motor 176 Cam 178 Cam Groove 180 Air Cylinder 182 Ink Recovery Device 184 Recovery Box 186 Rubber Plate 210 Fixing Device 212 Heater 214 Heating Fins 216a, 216b Heating Section 218 Temperature Sensor 220 Steam Inlet 222 Lit 224 injection plate 226 serpentine passage

Claims (9)

[Claims] 1. A static ink for rubbing the powder ink onto a screen on which a predetermined printing pattern is formed, and applying a voltage between the screen and the printed material to attach the powder ink to the printed material. An electric printing apparatus, a conveyor for conveying an object to be printed, a screen moving mechanism for moving a plurality of screens above the object to be moved moved by the conveyor, and a moving speed of the object to be printed by the conveyor and the An electrostatic printing apparatus comprising: a synchronizing mechanism that synchronizes a moving speed of the screen by a screen moving mechanism. 2. A height detection sensor for detecting the height of a print object on the conveyor on the upstream side of a printing position, and a height detection sensor for determining the height of the print object based on a detection result of the height detection sensor. The electrostatic printing apparatus according to claim 1, further comprising a lifter that vertically moves the transport conveyor. 3. A screen unit having a flat plate having an opening for arranging the screen and a side piece attached to an upper surface of one side of the flat plate, the side piece being arranged in the opening. And a protrusion that protrudes from one side of the flat plate, and the length of the protrusion of the side piece is the distance from the other side of the flat plate to the opening. The electrostatic printing device according to claim 1, wherein the electrostatic printing device is longer than the above. 4. The electrostatic printing apparatus according to claim 3, wherein a corner of the side piece is bent upward. 5. A cylindrical screen brush for rubbing the powder ink onto the screen, and the powder ink is supplied to the screen brush from a position on the rotation direction side of the screen brush immediately above the center of the screen brush. 5. An electrostatic printing apparatus according to claim 1, further comprising a hopper that operates. 6. A screen brush for rubbing powdered ink onto the screen, a printing material detection sensor for detecting whether or not a printing material is placed on the transport conveyor at an upstream side of a printing position, and the printing material When it is determined that the material to be printed is placed on the conveyor based on the detection result of the printed matter detection sensor, when the material to be printed on the conveyor is located at the printing position, the screen brush is The electrostatic printer according to claim 1, further comprising a brush separating mechanism that separates from the screen. 7. A contact piece that comes into contact with the upper surface and / or the lower surface of the screen that is moved by the screen moving mechanism after printing is performed, and a collection box that collects the powder ink scraped by the contact piece. 7. An ink collecting device having the following is further provided:
The electrostatic printing device according to claim 1. 8. A static ink for rubbing the powder ink onto a screen on which a predetermined printing pattern is formed, and applying a voltage between the screen and the printed material to attach the powder ink to the printed material. An electrostatic printing apparatus, comprising: a cylindrical screen brush that rubs powder ink onto the screen; and a screen brush drive mechanism that rotates the screen brush and simultaneously moves the screen brush in the axial direction. Electric printing device. 9. A static ink for rubbing the powder ink onto a screen on which a predetermined printing pattern is formed, and applying a voltage between the screen and the printed material to attach the powder ink to the printed material. An electric printing apparatus, comprising a plurality of heating fins arranged alternately, a heater for heating the heating fins, a temperature sensor for detecting and controlling the temperature of the heater, and heated high-temperature steam on a printing object. And a fixing device for generating a steam having a temperature necessary for fixing the printing object by bringing the steam introduced from the steam introducing port into contact with a heating fin. And an electrostatic printing device.