JP2008023949A - Electrostatic printing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic printing device which can print accurately and clearly with a low cost and a compact constitution. <P>SOLUTION: The electrostatic printing device 1 comprises a printing stage 10 in which a matter to be printed is placed, a fixed frame 30 having a guide shaft 33 extending in a horizontal direction, and a movable frame 20. The movable frame 20 has a screen unit 22 which aligns in an axial direction of the guide shaft 33 and holds screens 21A, 21B, and 21C where predetermined printing patterns are formed, and a bearing unit 25 which can slide the screen unit 22 in an axial direction of the guide shaft 33 and can rotate with the guide shaft 33 as a center. The electrostatic printing device 1 comprises a positioning mechanism which positions the screens 21A, 21B, and 21C at the printing position above the printing stage 10. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrostatic printing apparatus, and more particularly to an electrostatic printing apparatus that attaches powder ink to a surface of a printing material using electrostatic force and prints a printing pattern such as characters and figures on the surface of the printing material. is there.

  2. Description of the Related Art Conventionally, electrostatic printing apparatuses that use electrostatic force to attach powder ink to the surface of a printing material and print a printing pattern such as letters and figures on the surface of the printing material are known. Since conventional electrostatic printing apparatuses can only print with one color of powder ink, when performing multicolor printing on a substrate, it is necessary to install as many electrostatic printing apparatuses as the number of colors to be used.

  FIG. 1 is a longitudinal sectional view showing a device configuration in the case of performing three-color printing using a conventional electrostatic printing device. In the example shown in FIG. 1, first, the first color is printed in the electrostatic printing apparatus 200a, and then the pallet 150 on which the printing material 100 is placed is transferred to the next electrostatic printing apparatus 200b. In 200b, the second color is printed. Then, after the second color printing is completed in the electrostatic printing apparatus 200b, the pallet 150 is further transferred to the next electrostatic printing apparatus 200c, and the third color printing is performed in the electrostatic printing apparatus 200c. As described above, when multicolor printing is performed using a conventional electrostatic printing apparatus, a plurality of electrostatic printing apparatuses are installed, and printing by each color is performed by each electrostatic printing apparatus.

  As described above, when multi-color printing is performed using a conventional electrostatic printing apparatus, it is necessary to install as many electrostatic printing apparatuses as the number of colors to be used, which requires a large installation space. The cost for doing this will also be very high.

  In addition, when the pallet on which the substrate is placed is transferred to the next electrostatic printing device, the position of the pallet is shifted with respect to the screen, or due to vibration or impact during transfer, the substrate to be printed in the pallet. May be misaligned. In such a case, since the printing position differs depending on the color, accurate and clean printing cannot be performed on the substrate.

  The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide an electrostatic printing apparatus capable of performing accurate and clean printing with a low-cost and compact configuration. .

  According to one embodiment of the present invention, an electrostatic printing apparatus capable of performing accurate and clean printing with a low-cost and compact configuration is provided. This electrostatic printing apparatus includes a printing stage on which a substrate is placed, a fixed frame having a guide shaft extending in the horizontal direction, and a movable frame. The movable frame includes a screen unit that holds a plurality of screens each having a predetermined printing pattern arranged in the axial direction of the guide shaft, and allows the screen unit to slide in the axial direction of the guide shaft. And a bearing portion that is rotatable about the guide shaft. The electrostatic printing apparatus includes a positioning mechanism that positions each of the plurality of screens at a printing position above the printing stage, and a power source that applies a voltage between the screen and the printing stage. . In this case, the positioning mechanism may have a plurality of pairs of a pair of members that contact each other.

  The fixed frame may further include a shaft support that supports the guide shaft. In this case, a plurality of openings may be formed in the shaft support corresponding to the position of the bearing portion when the plurality of screens are respectively positioned at the printing positions.

  The fixed frame may further include a lift mechanism that rotates the screen unit around the guide shaft to lift it. In this case, the lift mechanism may include a pressing element that presses a part of the movable frame to rotate the screen unit, and a spring that biases the pressing element. The lift mechanism is preferably configured to release contact between the pressing element and a part of the movable frame when the screen unit is lifted above a predetermined position. Further, the fixed frame may have a block that prevents the screen unit from being lifted upward from a predetermined position. Further, the electrostatic printing apparatus starts to apply a voltage by the power source when the screen unit is pressed down from a predetermined position, and the screen unit is lifted by the lift mechanism. A switch may be further provided that stops contact with the screen unit and stops the application of voltage by the power source.

  According to the present invention, it is possible to perform multicolor printing with one electrostatic printing device without installing a plurality of electrostatic printing devices as in the prior art. Therefore, the installation space can be reduced to a compact configuration, and the required high-voltage DC power supply and various devices are sufficient, so the cost for multicolor printing can be greatly reduced. It becomes possible.

  Also, printing with powder inks of different colors is possible with the substrate to be stationary, and each screen is also accurately positioned by the positioning mechanism, so that the printing position is not shifted by color. . Therefore, it is possible to perform accurate and clean printing on the substrate.

  Hereinafter, embodiments of the electrostatic printing apparatus according to the present invention will be described in detail with reference to FIGS. 2 to 11, the same or corresponding components are denoted by the same reference numerals, and redundant description is omitted.

  2 is a front view showing the electrostatic printing apparatus 1 according to an embodiment of the present invention, FIG. 3 is a plan view of FIG. 2, and FIG. 4 is a side view of FIG. As shown in FIGS. 2 to 4, the electrostatic printing apparatus 1 includes a printing stage 10 on which a printing material is placed, a movable frame 20 that is movable in the horizontal direction, and a fixed frame 30 that supports the movable frame 20. It has. A DC power supply (not shown) is connected to the printing stage 10, and a substrate such as confectionery is placed on the printing stage 10.

  5 is a front view showing a part of the fixed frame 30, and FIG. 6 is a plan view of FIG. As shown in FIGS. 2 to 6, the fixed frame 30 includes a base plate 31, a pair of support columns 32 </ b> A and 32 </ b> B that support the base plate 31, a guide shaft 33 that extends in the horizontal direction, and a guide shaft 33 on the base plate 31. It has a shaft support 34 that supports it, and a pair of rear plates 35 </ b> A and 35 </ b> B that extend vertically behind the printing stage 10.

  7 is a front view showing the movable frame 20, and FIG. 8 is a plan view of FIG. As shown in FIGS. 7 and 8, the movable frame 20 includes three stencil screens 21A, 21B, 21C arranged in the axial direction of the guide shaft 33 of the fixed frame 30, and these stencil screens 21A, 21B, 21C. A screen unit 22 to be held, a handle 23 provided on the upper surface of the screen unit 22, and a base portion 24 having an L-shaped cross section attached to the screen unit 22. Each stencil screen 21A, 21B, 21C is formed of a conductive material, and a predetermined print pattern such as characters and figures is formed on each stencil screen 21A, 21B, 21C by a mesh net. . The potentials of these stencil screens 21A, 21B, and 21C are set to the ground potential.

  Three bearing portions 25 are attached to the lower surface of the base portion 24 along the axial direction of the guide shaft 33 of the fixed frame 30, and the bearing portions 25 are attached to the guide shaft 33 of the fixed frame 30. The bearing portion 25 enables the screen unit 22 to slide in the axial direction of the guide shaft 33 and allows the screen unit 22 to rotate about the guide shaft 33.

  The printing stage 10 is supported by a pair of stage arms 11, and the vertical position of the stage arm 11 can be adjusted by a handle (not shown). Therefore, the distance between the printing stage 10 and the screen unit 22 of the movable frame 20 can be adjusted by operating the handle. A base 12 incorporating a power switch 12A, a voltage control switch 12B, a voltage meter 12C, and the like is disposed below the printing stage 10.

  As shown in FIG. 4, a link member 41 </ b> A is attached to the upper portion of the rear plate 35 </ b> A so as to be rotatable about a shaft 42. At the end of the link member 41A, a pressing roller 43A as a pressing member that presses the upper surface of the base 24 of the movable frame 20 and rotates the screen unit 22 around the guide shaft 33, and a first stencil screen 21A are provided. A first stopper 44A for positioning at a printing position above the printing stage 10 is provided. The link member 41A is urged downward by two springs 45A attached to the rear plate 35A. As a result, as shown in FIG. 9, the pressing roller 43A presses the upper surface of the base 24 of the movable frame 20 downward, rotates the screen unit 22 around the guide shaft 33, and lifts it up. Yes.

  Similarly, as shown in FIG. 3, a link member 41 </ b> B is attached to the upper portion of the other rear plate 35 </ b> B so as to be rotatable about a shaft 42. At the end of the link member 41A, a pressing roller 43B as a pressing member that presses the upper surface of the base 24 of the movable frame 20 and rotates the screen unit 22 around the guide shaft 33, and a second stencil screen 21B are provided. A second stopper 44B for positioning at the printing position and a third stopper 44C for positioning the third stencil screen 21C at the printing position are provided. The link member 41B is urged downward by two springs 45B attached to the rear plate 35B. Thereby, the pressing roller 43B presses the upper surface of the base 24 of the movable frame 20 downward, rotates the screen unit 22 around the guide shaft 33, and lifts it.

  Thus, in this embodiment, the lift mechanism which rotates and lifts the screen unit 22 centering on the guide shaft 33 is comprised by press roller 43A, 43B and spring 45A, 45B. This lift mechanism makes it possible to easily lift the screen unit 22. As shown in FIG. 9, a contact-type switch 14 is provided at the upper end of the base 12, and this switch 14 is connected to the screen unit 22 when the screen unit 22 is pushed down from a predetermined position. To come into contact. When the switch 14 contacts the screen unit 22, a voltage is applied between the screens 21 </ b> A, 21 </ b> B, 21 </ b> C and the printing stage 10 by a DC power source. When the screen unit 22 is lifted by the lift mechanism, the contact between the switch 14 and the screen unit 22 is released, and the application of voltage by the DC power supply is stopped.

  As shown in FIG. 8, the movable frame 20 includes a first guide member 26 </ b> A provided on the upper surface of one end 24 </ b> A of the base 24 and an L provided on the upper surface in the vicinity of the other end 24 </ b> B of the base 24. The second guide member 26 </ b> B having a letter arm shape and the third guide member 26 </ b> C provided on the upper surface of the other end 24 </ b> B of the base 24. As shown in FIG. 7, the second guide member 26B is configured to be rotatable about a shaft 28 attached to the third guide member 26C, and is indicated by a guide position indicated by a solid line and a two-dot chain line. Two states of the standing position can be taken.

  Here, as shown in FIG. 8, the first guide member 26A has a guide surface 27A that comes into contact with the first stopper 44A described above, and the second guide member 26B comes into contact with the second stopper 44B. The third guide member 26C has a guide surface 27C that abuts against the third stopper 44C. As shown in FIG. 10, the first stencil screen 21 </ b> A in the screen unit 22 is positioned above the printing stage 10 at a position where the first stopper 44 </ b> A contacts the guide surface 27 </ b> A of the first guide member 26 </ b> A. It has become. Further, as shown in FIG. 3, the second stencil screen 21B in the screen unit 22 is positioned above the printing stage 10 at a position where the second stopper 44B contacts the guide surface 27B of the second guide member 26B. It is supposed to be. Furthermore, as shown in FIG. 11, the second stencil screen 21C in the screen unit 33 is positioned above the printing stage 10 at a position where the third stopper 44C contacts the guide surface 27C of the third guide member 26C. It is supposed to be.

  As described above, in the present embodiment, the first stencil screen 21A in the screen unit 22 is positioned at the printing position above the printing stage 10 by the first guide member 26A and the first stopper 44A that are in contact with each other. A positioning mechanism is configured, and a positioning mechanism for positioning the second stencil screen 21B at the printing position is configured by the second guide member 26B and the second stopper 44B that are in contact with each other, and a third guide member that is in contact with each other. 26C and the third stopper 44C constitute a positioning mechanism for positioning the third stencil screen 21C at the printing position.

  As shown in FIGS. 5 and 6, the shaft support 34 is formed with five openings 51 to 55 that penetrate in a direction perpendicular to the axial direction of the guide shaft 33. These openings 51 to 55 are formed corresponding to the bearing portion 25 of the movable frame 20, and when the first stencil screen 21 </ b> A is in the printing position, 3 to the portion where the openings 51 to 53 are formed. Two bearing portions 25 are positioned. Therefore, in this position, the screen unit 22 can be rotated around the guide shaft 33 without the shaft support 34 interfering with the bearing portion 25. Similarly, when the second stencil screen 21B is in the printing position, the three bearing portions 25 are positioned at the portions where the openings 52 to 54 are formed, and the third stencil screen 21C is When in the printing position, the three bearing portions 25 are positioned in the portions where the openings 53 to 55 are formed. Note that the number of the bearing portions 25 is not limited to the illustrated one. Moreover, the opening of the shaft support 34 should just be provided corresponding to the bearing part 25, and the number is not restricted to what was illustrated.

  An operation in the case of performing multicolor printing of a printing material using the electrostatic printing apparatus 1 having such a configuration will be described. First, a substrate such as confectionery is placed on the printing stage 10. The printed material is not limited to food such as confectionery, and may be, for example, an industrial product.

  Next, as shown in FIG. 9, the screen unit 22 is lifted upward. At this time, the screen unit 22 can be easily lifted by the above-described lift mechanism. Here, the link members 41A and 41B are rotatable within a predetermined angle range, and when the screen unit 22 is lifted further upward from a predetermined position, the pressing rollers 43A and 43B and the base 24 of the movable frame 20 are connected. The contact with the upper surface is released. In this state, the contact between the pressing rollers 43 </ b> A and 43 </ b> B and the upper surface of the base 24 is released, so that the screen unit 22 can be easily moved in the axial direction of the guide shaft 33. As shown in FIG. 9, a block 46 is attached to the rear plates 35 </ b> A and 35 </ b> B, and the end of the base 24 of the movable frame 20 is locked to the block 46, so that the screen unit 22 becomes excessive. It is prevented from being lifted upward.

  As described above, the screen unit 22 is moved until the guide surface 27A of the first guide member 26A comes into contact with the first stopper 44A in a state where the contact between the pressing rollers 43A and 43B and the upper surface of the base 24 is released. It moves in the axial direction of the guide shaft 33. When the guide surface 27A of the first guide member 26A comes into contact with the first stopper 44A, the screen unit 22 is rotated and pushed down around the guide shaft 33, and the first stencil screen 21A is printed above the printing stage 10. Move to position (state shown in FIG. 10).

  Here, as shown in FIGS. 4 and 9, the base 12 of the fixed frame 30 is provided with a stopper bar 13 that extends upward, so that the screen unit 22 is excessively pushed down and the cover on the printing stage 10 is covered. Contact with the printed matter is prevented.

  In a state where the first stencil screen 21A is at the printing position, the first color powder ink is sprayed on the upper surface of the first stencil screen 21A, and this powder ink is rubbed into the stencil screen with a urethane sponge brush or the like. As such powder ink, various powders such as edible ink containing natural pigment or synthetic pigment, cocoa powder, wheat flour, matcha powder, sugar powder, or industrial powder ink can be used. Can be used.

  At this time, the switch 14 at the upper end of the base 12 is pushed by the screen unit 22, and a DC high voltage, for example, a high voltage of 5000 to 6000 V, for example, is applied between the first stencil screen 21A and the printing stage 10 by the DC power supply. An electrostatic field is formed between the stencil screen 21 </ b> A and the printing stage 10. The powder ink rubbed into the first stencil screen 21A is pushed downward from the mesh net of the stencil screen 21A, but the charged powder ink passing through the mesh net is a printing stage which is a counter electrode by the electrostatic field. 10. That is, the ink is accelerated toward the printing material, and the first color powder ink adheres to the printing material. In this way, the first color printing is completed.

  After the printing of the first color is completed, the screen unit 22 is rotated about the guide shaft 33 and lifted upward as shown in FIG. Thereby, the contact between the switch 14 and the screen unit 22 is released, and application of a high voltage by the DC power supply is stopped. Then, the screen unit 22 is moved in the axial direction of the guide shaft 33 until the guide surface 27B of the second guide member 26B comes into contact with the second stopper 44B. Thus, in the present embodiment, the switch 14 that contacts the screen unit 22 applies a high voltage only when printing is performed, and the high voltage application is always stopped when the screen unit 22 is moved. Operator safety is ensured. When the guide surface 27B of the second guide member 26B comes into contact with the second stopper 44B, the screen unit 22 is rotated and pushed down around the guide shaft 33, and the second stencil screen 21B is printed above the printing stage 10. Move to position (state shown in FIG. 3). In the same manner as described above, the second color powder ink is sprayed on the upper surface of the second stencil screen 21B, and this is rubbed into the second stencil screen 21B. At this time, a DC high voltage is applied between the second stencil screen 21B and the printing stage 10 by a DC power source, and the second color powder ink adheres to the printing material. In this way, printing of the second color is completed.

  After the second color printing is completed, as shown in FIG. 9, when the screen unit 22 is rotated about the guide shaft 33 and lifted upward, the application of a high voltage by the DC power supply is stopped. Then, the second guide member 26B is rotated about the shaft 28 and lifted. In this state, the screen unit 22 is moved in the axial direction of the guide shaft 33 until the guide surface 27C of the third guide member 26C comes into contact with the third stopper 44C. When the guide surface 27C of the third guide member 26C comes into contact with the third stopper 44C, the screen unit 22 is rotated and pushed down around the guide shaft 33, and the third stencil screen 21C is printed above the printing stage 10. Move to position (state shown in FIG. 11). Then, in the same manner as described above, the third color powder ink is sprayed on the upper surface of the third stencil screen 21C, and this is rubbed into the third stencil screen 21C. At this time, a DC high voltage is applied between the third stencil screen 21 </ b> C and the printing stage 10 by a DC power source, and the third color powder ink adheres to the printed material. In this way, the third color printing is completed.

  As described above, in the present embodiment, three-color printing can be performed using the three stencil screens 21A, 21B, and 21C. Note that multicolor printing with an arbitrary number of colors can be performed by changing the number of stencil screens. Further, as in this embodiment, each color stencil screen may be sprayed with different color powder inks to perform multicolor printing, or may be sprayed with different types of powder inks for printing. May be.

  Thus, according to the electrostatic printing apparatus according to the present invention, it is possible to perform multicolor printing with one electrostatic printing apparatus. Therefore, the installation space can be reduced to a compact configuration, and the required high-voltage DC power supply and various devices are sufficient, so the cost for multicolor printing can be greatly reduced. It becomes possible.

  In addition, it is possible to perform multicolor printing with powder inks of different colors while the printed material is placed still on the printing stage 10, and the stencil screens 21A, 21B, and 21C are also provided by the positioning mechanism described above. Accurate positioning. Therefore, the printing position does not shift depending on the color, and accurate and clean printing can be performed on the substrate.

  In the above-described embodiment, the example in which the potential of the stencil screen is set to the ground potential has been described. However, the present invention is not limited to this, and a DC power source is connected to the stencil screen and the potential of the printing stage is set to the ground potential. You can also.

  In the above-described embodiment, the positioning mechanism for positioning the stencil screens 21A, 21B, and 21C in the screen unit 22 at the printing position is the guide members 26A, 26B, and 26C provided on the movable frame 20 and the stoppers 44A and 44B. However, the positioning mechanism is not limited to this. For example, a positioning mechanism may be constituted by a protrusion (male member) provided on the movable frame 20 and a V-shaped groove (female member) provided on the fixed frame 30, or a V-shaped groove provided on the movable frame 20. A positioning mechanism may be configured by the (female member) and the protrusion (male member) provided on the fixed frame 30.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and it goes without saying that the present invention may be implemented in various forms within the scope of the technical idea.

It is a longitudinal cross-sectional view which shows the apparatus structure in the case of performing three-color printing using the conventional electrostatic printing apparatus. It is a front view which shows the electrostatic printing apparatus in one Embodiment of this invention. FIG. 3 is a plan view of FIG. 2. FIG. 3 is a side view of FIG. 2. It is a front view which shows a part of fixed frame in the electrostatic printing apparatus shown in FIG. FIG. 6 is a plan view of FIG. 5. It is a front view which shows the movable frame in the electrostatic printing apparatus shown in FIG. FIG. 8 is a plan view of FIG. 7. FIG. 3 is a side view showing a state where a movable frame is lifted in the electrostatic printing apparatus shown in FIG. 2. FIG. 3 is a plan view showing a state when a first stencil screen of a movable frame is in a printing position in the electrostatic printing apparatus shown in FIG. 2. FIG. 3 is a plan view showing a state when a third stencil screen of a movable frame is in a printing position in the electrostatic printing apparatus shown in FIG. 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Printing stage 13 Stopper bar 14 Switch 20 Movable frame 21A, 21B, 21C Stencil screen 22 Screen unit 24 Base part 25 Bearing part 26A, 26B, 26C Guide member 27A, 27B, 27C Guide surface 30 Fixed frame 33 Guide shaft 34 Shaft support 41A , 41B Link member 43A, 43B Pressure roller 44A, 44B, 44C Stopper 45A, 45B Spring 46 Block 51-55 Opening

Claims (9)

A printing stage on which the substrate is placed;
A fixed frame having a horizontally extending guide shaft;
A screen unit that holds a plurality of screens each having a predetermined printing pattern arranged in the axial direction of the guide shaft, and enables the screen unit to slide in the axial direction of the guide shaft, and the guide shaft as a center. A movable frame having a bearing portion that is rotatable;
A positioning mechanism for positioning each of the plurality of screens at a printing position above the printing stage;
A power supply for applying a voltage between the screen and the printing stage;
An electrostatic printing apparatus comprising:   The electrostatic printing apparatus according to claim 1, wherein the fixed frame further includes a shaft support that supports the guide shaft.   3. The static support according to claim 2, wherein the shaft support has a plurality of openings corresponding to positions of the bearing portions when the plurality of screens are positioned at the printing positions. Electric printing device.   The electrostatic printing apparatus according to claim 1, wherein the positioning mechanism includes a plurality of pairs of a pair of members that are in contact with each other.   5. The electrostatic printing apparatus according to claim 1, wherein the fixed frame further includes a lift mechanism that rotates the screen unit around the guide shaft to lift the screen unit. 6. The lift mechanism is
A pressing member that presses a part of the movable frame to rotate the screen unit;
A spring for biasing the pressing element;
The electrostatic printing apparatus according to claim 5, comprising:   The lift mechanism is configured to release contact between the pressing element and a part of the movable frame when the screen unit is lifted above a predetermined position. Item 7. The electrostatic printing apparatus according to Item 6.   The electrostatic printing apparatus according to claim 7, wherein the fixed frame further includes a block that prevents the screen unit from being lifted upward from a predetermined position.   When the screen unit is pressed down from a predetermined position, the screen unit comes into contact with the screen unit to start applying a voltage by the power source. When the screen unit is lifted by the lift mechanism, the screen unit comes into contact with the screen unit. The electrostatic printing apparatus according to claim 6, further comprising a switch that disconnects and stops application of a voltage by the power source.

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