CN111169170B - Direction-changeable ink drop deflection device and multi-nozzle spray head - Google Patents

Abstract

The present invention relates to the technical field of inkjet printer nozzles, and more specifically, to a variable ink drop deflection device and a multi-nozzle nozzle, comprising a nozzle, a charging electrode, a phase sensor, an electric field deflection area and a recovery tank arranged in sequence, the electric field deflection area comprising a first deflection plate and a second deflection plate arranged oppositely, the first deflection plate comprising a first electrode and a second electrode, the first electrode and the second electrode are respectively arranged on both sides of the ink feed direction, and the first electrode and the second electrode are connected to a voltage output electrode with different voltage magnitudes and the same polarity. A multi-nozzle nozzle, a plurality of variable ink drop deflection devices are spliced together side by side, so that the deflection direction of the charged ink drop is not fixed in a plane perpendicular to the deflection plate, that is, the deflection direction is variable, and the angle of the change in the deflection direction just offsets the inclination angle of the longitudinal column of ink dots caused by the time difference of the ink droplets falling on the printed object, so that the longitudinal columns of ink dots printed by different nozzles can be connected into a straight line, so that the information presented on the printed object is more beautiful and accurate.

Description

A variable-direction ink drop deflection device and a multi-nozzle printhead

Technical Field

The present invention relates to the technical field of inkjet printer nozzles, and more specifically, to a variable-direction ink drop deflection device and a multi-nozzle nozzle.

Background Art

An inkjet printer is a device that uses software control to encode and mark products in a non-contact manner. It is widely used in printing labels on the outer packaging of pipes, profiles, strips or other products.

When the inkjet printer is printing, it charges the ink droplets to be printed with different levels of electric charge one by one. When the ink droplets with different charges pass through the high-voltage electric field, under the action of the electric field force, they will be deflected away from the nozzle at different deflection amounts and fall on the surface of the printed object, forming a column of longitudinal ink dots. Combined with the lateral movement of the printed object, the combination of multiple columns of longitudinal ink dots forms character or pattern information on the printed object.

Because the most reasonable charging method in the prior art is: each column of longitudinal ink droplets is charged one by one from low charge to high charge. That is, each column of ink droplets first sprays out ink droplets with a small deflection, and then sprays out ink droplets with a large deflection. Due to the time difference between the ink droplets reaching the printed material and the lateral movement of the printed material, each column of longitudinal ink dots will appear slightly tilted on the printed material, that is, the longitudinal column of ink dots is not perpendicular to the bottom edge of its complete information, and the printed information appears tilted. The faster the conveying line of the printed material, the more obvious this phenomenon is. Although the aesthetics of the printed information is not greatly affected in the single-nozzle single-nozzle application, as shown in Figure 16, the printed text is tilted in one direction.

However, in high-speed printing with multiple nozzles, especially in high-speed printing applications with dual nozzles, the aesthetics of the printed information will be seriously reduced. For example, when the dual nozzles of the opposite deflection type print information at high speed, the upper part of the information is sprayed out by one nozzle and printed in a deflection manner from top to bottom, and the lower part of the information is sprayed out by another nozzle and printed in a deflection manner from bottom to top. As a result, the longitudinal columns of ink dots in the upper part of the information are tilted to one side, while the longitudinal columns of ink dots in the lower part are tilted to the other side. Therefore, each longitudinal column of ink dots that constitutes the complete information will not be straight from top to bottom, but will present a “>” shape, or a “<” shape when the direction of the printed material is opposite. The opposite deflection type dual nozzle nozzle is similar to the above phenomenon. As shown in Figure 15, if the dual nozzle nozzle prints two lines of text at the same time, the upper and lower lines of text will have opposite tilt directions; as shown in Figure 17, if the dual nozzle nozzle prints the same text at the same time, the upper and lower parts of the text will have opposite tilt directions. The faster the conveyor line of the printed material is, the more serious the above phenomenon is, which seriously affects the aesthetics of the printed information.

Summary of the invention

The object of the present invention is to overcome the deficiencies of the prior art and to provide a variable-direction ink drop deflection device and a multi-nozzle printhead, so that the deflection direction of charged ink droplets is not fixed on a plane perpendicular to the deflection plate, that is, the deflection direction is variable, and the angle of change in the deflection direction can just offset the inclination angle of the longitudinal column of ink dots caused by the time difference of the ink droplets falling on the printed object, so that the longitudinal columns of ink dots printed by different nozzles can be connected into a straight line, making the information presented on the printed object more beautiful and accurate.

In order to solve the above technical problems, the technical solution adopted by the present invention is: a variable-direction ink droplet deflection device, comprising a nozzle, a charging electrode, a phase sensor, an electric field deflection zone and a recovery groove arranged in sequence, the electric field deflection zone comprises a first deflection plate and a second deflection plate arranged opposite to each other, the first deflection plate comprises a first electrode and a second electrode, the first electrode and the second electrode are respectively arranged on both sides of the ink feed direction, and the first electrode and the second electrode are connected to a voltage output electrode with different voltage magnitudes and the same polarity.

In this device, the nozzle sprays ink droplets, and the ink droplets carry electric charges after passing through the charging electrode. At present, the ink droplets are generally charged with negative charges. The ink droplets carrying negative charges enter the electric field deflection area. The electric field deflection area is composed of a first deflection plate and a second deflection plate. The two electrodes of the first deflection plate are respectively connected to two different positive voltage output electrodes, and the second deflection plate is connected to the negative voltage output electrode. A high-voltage electric field is formed between the first deflection plate and the second deflection plate. When the charged ink droplets enter the electric field deflection area, they are deflected in the direction of high potential, thereby hitting the surface of the printed object, that is, the ink droplets are offset on a plane approximately perpendicular to the first deflection plate and the second deflection plate, and move through the conveying line of the printed object to print the required characters on the surface of the printed object. In this device, since the voltages connected to the first electrode and the second electrode provided on the first deflection plate are different, the electric field strengths on both sides of the first deflection plate are different in the electric field deflection area, and the direction of deflection of the charged ink droplets is offset to the side with high electric field strength, so that the ink droplet trajectory surface changes. During the printing process, by adjusting the voltages connected to the first electrode and the second electrode of the first deflection plate, the offset direction of the ink droplets is changed to the moving direction of the printed object, and the angle of change just offsets the inclination angle of the longitudinal column of ink dots caused by the time difference of the ink droplets falling on the printed object, so that the longitudinal column of ink dots is vertically printed on the surface of the printed object, and vertical fonts are printed. In particular, in a multi-nozzle nozzle, it can be ensured that the fonts printed by each nozzle will not be tilted, so that the longitudinal columns of ink dots printed by different nozzles can be connected into a straight line. The information presented on the printed object is more beautiful and accurate.

Furthermore, the first deflection plate further comprises a resistor, and the two sides of the resistor are respectively connected to the first electrode and the second electrode. The resistor is made of a uniform weakly conductive resistor material, which can distribute the electric field on the entire working surface while reducing the working current, and can evenly transition from the weak electric field area to the strong electric field area, so that the deflection direction of the ink droplet can be stably controlled.

Furthermore, the resistor body is one or more combinations of weakly conductive plastic, ceramic or resistor film.

Furthermore, the first electrode and the second electrode on both sides of the first deflection plate are connected to voltages of different magnitudes to achieve different electric field strengths on both sides of the first deflection plate. The magnitude of the connected voltage is adjusted according to the actual moving speed and direction of the conveying line of the printed object, so that the inclination of the longitudinal column of ink dots caused by the time difference when the ink droplets reach the printed object will be compensated by the change in the deflection direction of the ink droplets and eliminated.

Furthermore, openings are respectively provided on both sides of the resistor, and the first electrode and the second electrode are respectively inserted into the openings.

Furthermore, the first deflection plate also includes an insulating base plate, the first electrode and the second electrode are electrode layers coated on both ends of the insulating base plate respectively, and a resistor layer is also arranged on the insulating base plate, and the resistor layer is respectively connected to the electrode layers at both ends.

Furthermore, the first electrode is a first electrode plate, the second electrode is a second electrode plate, and the first electrode plate and the second electrode plate are separately arranged. The first electrode plate and the second electrode plate are separated by a certain effective distance to prevent electrical breakdown.

Furthermore, the corresponding sides of the first electrode plate and the second electrode plate are inclined surfaces, which can make the deflection electric field more evenly distributed or gradually distributed, so that the deflection electric field has no obvious splitting, so that the deflection direction of the ink droplet can be stably controlled.

Furthermore, the first deflection plate is a positive electrode deflection plate, and the second deflection plate is a negative electrode deflection plate, and a high voltage electric field is formed between the positive electrode deflection plate and the negative electrode deflection plate.

A multi-nozzle printhead, comprising the above-mentioned variable-direction ink drop deflection device;

The two second deflection plates are respectively arranged on both sides of the first deflection plate;

or the two first deflection plates are respectively arranged on both sides of the second deflection plate;

Or a plurality of the variable-direction ink drop deflection devices are spliced together side by side, and a plurality of first deflection plates and second deflection plates are arranged opposite to each other.

Compared with the prior art, the beneficial effects of the present invention are as follows: the present device can make the deflection direction of the printed ink droplets variable, so that the angle of change in the deflection direction just offsets the inclination angle of the longitudinal column of ink dots caused by the time difference of the ink droplets falling on the printed object, so that the longitudinal columns of ink dots printed by different nozzles can be connected into a straight line, making the information presented on the printed object more beautiful and accurate. Especially in the application of multi-nozzle printheads, it can be ensured that the fonts printed by each nozzle will not be tilted, so that the longitudinal columns of ink dots printed by different nozzles can be connected into a straight line.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the overall structure of the present invention;

Fig. 2 is a right side view of Fig. 1;

FIG3 is a schematic diagram of a first structure of a first deflection plate in one embodiment of the present invention;

FIG4 is a right side view of FIG3;

FIG5 is a schematic diagram showing the front view of ink drop deflection;

FIG6 is a schematic diagram showing the side view of ink drop deflection;

FIG7 is a schematic diagram of the change in deflection direction of the ink drop in FIG6 ;

FIG8 is a schematic diagram of a second structure of a first deflection plate in one embodiment of the present invention;

FIG9 is a right side view of FIG8;

FIG10 is a schematic diagram showing the deflection direction of ink droplets in the structure of FIG9;

FIG11 is a schematic diagram of a structure of a double-nozzle spray head in one embodiment of the present invention;

FIG12 is another schematic diagram of the structure of a double-nozzle spray head in one embodiment of the present invention;

FIG13 is a schematic diagram of a third structure of the first deflection plate in one embodiment of the present invention;

FIG14 is a schematic diagram of a fourth structure of the first deflection plate in one embodiment of the present invention;

FIG15 is a schematic diagram of a dual-nozzle printhead in the prior art when printing two lines of text at high speed;

FIG16 is a schematic diagram of a single nozzle printhead in the prior art when printing a line of text at high speed;

FIG. 17 is a schematic diagram of a dual-nozzle printhead in the prior art when printing a line of text at high speed.

DETAILED DESCRIPTION

The present invention is further described below in conjunction with specific implementation methods. The accompanying drawings are only used for exemplary descriptions and are only schematic diagrams, not actual drawings, and cannot be understood as limiting this patent; in order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the accompanying drawings may be omitted.

The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the drawings, it is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limitations on this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

Embodiment 1:

As shown in FIGS. 1 and 2, a variable-direction ink drop deflection device comprises a nozzle 3, a charging electrode 4, a phase sensor 5, an electric field deflection zone and a recovery groove 6 which are sequentially arranged on a substrate 7, wherein the electric field deflection zone is composed of a first deflection plate 1 and a second deflection plate 2, the first deflection plate 1 and the second deflection plate 2 are arranged relatively to each other, in this embodiment, the first deflection plate 1 is a positive electrode deflection plate, the second deflection plate 2 is a negative electrode deflection plate, and a high-voltage electric field is formed between the positive electrode deflection plate and the negative deflection deflection plate, as shown in FIG5, y is the injection direction of the ink drop, S is the static ink line, that is, the motion trajectory of the uncharged ink drop in the electric field deflection zone, E is the motion trajectory of the charged ink drop in the electric field deflection zone, X is the deflection amount of the charged ink drop, as shown in FIG6, A is the ink drop deflection direction perpendicular to the working surface of the deflection plate. After the charged ink droplets enter the electric field deflection area, they are deflected out of the nozzle with different deflection amounts and hit the surface of the printed object to form character or pattern information, while the uncharged ink droplets are not deflected and return to the recovery tank 6 for recovery.

In this embodiment, the first deflection plate 1 includes a first electrode 11 and a second electrode 12. Specifically, the first electrode 11 and the second electrode 12 are respectively arranged on the left and right sides of the ink feeding direction, and the first electrode 11 and the second electrode 12 are respectively externally connected to positive voltage output electrodes with different voltage magnitudes. The input voltage magnitudes of the first electrode 11 and the second electrode 12 can be adjusted according to actual needs, so that the electric field strengths on both sides of the first deflection plate 1 are different, thereby making the deflection direction and deflection amount of the ink droplets different.

In the present device, the nozzle 3 ejects ink droplets, which are charged with negative charges of varying degrees after passing through the charging electrode 4. Ink droplets with different charges pass through the electric field deflection zone, causing the ink droplets to be deflected in the direction A as shown in FIG7 , leaving the nozzle and falling on the surface of the printed object. In addition, since the voltages connected to the first electrode 11 and the second electrode 12 on both sides of the first deflection plate 1 are different, the electric field strength on the side of the first electrode 11 is different from the electric field strength on the side of the second electrode 12, and the charged ink droplets are offset to the side with higher electric field strength. As shown in FIG7 , if the conveying direction of the printed object is from left to right, during high-speed printing, the voltage connected to the first electrode 11 is reduced, and the voltage of the second electrode 12 is increased, so that the electric field strength in the electric field deflection zone is weak on the left and strong on the right, and the direction of the electric field attraction is offset to the right in the direction B. Similarly, when the direction of the printed material is from right to left at high speed, the access voltage of the first electrode 11 is increased, and the access voltage of the second electrode 12 is reduced, and the direction of the field force is shifted to the left in the direction of C, so that the angle of change in the deflection direction of the ink droplets just offsets the inclination angle of the longitudinal column of ink dots caused by the time difference of the ink droplets falling on the printed material, so that the ink dot columns are vertically printed on the surface of the printed material, and vertical fonts are printed. In a multi-nozzle nozzle, this structure can ensure that the fonts printed by each nozzle 3 will not be tilted, so that the longitudinal columns of ink dots printed by different nozzles 3 can be connected into a straight line. Make the information presented on the printed material more beautiful and accurate.

In particular, when the printing speed is very slow and the printing is little affected by the conveying speed of the printed material, the first electrode 11 and the second electrode 12 are connected to the same voltage to make the electric field strength on both sides of the first deflection plate 1 the same, so that the deflection electric field is a uniform electric field, and the ink droplets are deflected in the A direction.

In addition, the device can be used in conjunction with computer control when in use. When the inkjet printer is working, the data obtained by the test experiment of the device or the data obtained by calculation stored in the computer in advance is used to apply corresponding voltage values to the first electrode 11 and the second electrode 12 for the current printing speed and the conveying direction of the printed material, so that the inkjet printer hardly shows the inclination of the longitudinal column of ink dots within the maximum printing speed working range. In addition, the inkjet printer makes continuous adjustments and responds quickly according to the detected real-time speed and real-time direction of the printed material.

Specifically, as shown in FIGS. 3 and 4 , the first deflection plate 1 further includes a resistor 10, wherein the resistor 10 is made of a weakly conductive material, specifically one or more combinations of weakly conductive plastic, ceramic or resistor film, and the two ends of the resistor 10 are respectively connected to the first electrode 11 and the second electrode 12. The resistor 10 is made of a uniform weakly conductive resistor material, which can distribute the electric field on the entire working surface while reducing the working current, and can evenly transition from the weak electric field area to the strong electric field area, so that the deflection direction of the ink droplet can be stably controlled.

In particular, in actual applications, there is also a special design for charging the ink droplets to be printed with positive charges, the repulsive end deflection plate of the electric field deflection zone is connected to the positive voltage output electrode, and the attractive end deflection plate is connected to the negative voltage output electrode. Although the voltage polarities of the above two methods are opposite, they have the same principles, functions, and effects. Therefore, for the sake of clarity and accuracy, the description here is based on the method of charging the ink droplets to be printed with negative charges, which does not mean that the present invention is only suitable for this method.

Embodiment 2:

This embodiment is similar to the embodiment 1, except that, in this embodiment, as shown in FIG. 13, the first deflection plate 1 further includes a resistor 10, and the first electrode 11 and the second electrode 12 are respectively arranged at both ends of the resistor 10. The first electrode 11 and the second electrode 12 are connected to different voltages to achieve different electric field strengths on both sides of the first deflection plate 1. According to the actual moving speed and direction of the conveying line of the printed object, the size of the connected voltage is adjusted so that the inclination of the longitudinal column of ink dots caused by the time difference of the ink droplets arriving at the printed object will be compensated and eliminated by the change of the deflection direction of the ink droplets.

The resistor 10 has openings at both ends, and the first electrode 11 and the second electrode 12 are inserted into the openings. Specifically, the first electrode 11 and the second electrode 12 are embedded in the inside of both sides of the resistor.

Embodiment 3:

This embodiment is similar to embodiment 1 or 2, except that, in this embodiment, as shown in FIG. 14 , the first deflection plate 1 also includes an insulating base plate 14, the first electrode 11 and the second electrode 12 are electrode layers 15 respectively coated on both ends of the insulating base plate 14, and a resistor layer 16 is also provided on the insulating base plate 14, and the resistor layer 16 is respectively connected to the electrode layers 15 at both ends.

Embodiment 4:

This embodiment is similar to Embodiment 1, 2 or 3, except that, in this embodiment, as shown in FIGS. 8 and 9, the first electrode 11 is a first electrode plate 81, the second electrode 12 is a second electrode plate 82, the first electrode plate 81 and the second electrode plate 82 are separately arranged, and the side surfaces of the first electrode plate 81 and the second electrode plate 82 corresponding to each other are inclined surfaces. A certain effective distance is separated between the first electrode plate 81 and the second electrode plate 82 to prevent electrical breakdown.

As shown in FIG10 , the width of the working surface of the first electrode 81 is greater than the width of the working surface of the second electrode 82, so as to just cover the maximum value of the change in the deflection direction of the ink droplets toward the direction B. In this way, the ink droplets deflected toward the direction B are not disturbed. The first electrode 81 and the second electrode 82 form a deflection electric field together with the negative electrode deflection plate 2. The side surfaces corresponding to each other of the first electrode 81 and the second electrode 82 are arranged as inclined surfaces, so as to make the deflection electric field more uniformly distributed or gradually distributed, so that the deflection electric field has no obvious split, so as to stably control the deflection direction of the ink droplets.

Embodiment 5:

This embodiment is similar to the above embodiment, except that this embodiment is an application example of the device in a dual-nozzle nozzle of a counter-deflection type, as shown in Figure 11, the positive electrode deflection plate 111 installed on the substrate 7 is a positive electrode deflection plate shared by the first group of printing mechanisms and the second group of printing mechanisms, and its upper surface and lower surface are both working surfaces, the first positive electrode 112 is connected to the first positive voltage output electrode, the second positive electrode 113 is connected to the second positive voltage output electrode, the first negative electrode deflection plate 114 of the first group of printing mechanisms and the second negative electrode deflection plate 115 of the second group of printing mechanisms are respectively arranged on both sides of the positive electrode deflection plate 111, and the first negative electrode deflection plate 114 and the second negative electrode deflection plate 115 are both connected to the same negative voltage output electrode. In the figure, the charged ink droplets of the first group of printing mechanisms located at the upper part are deflected downward, and the charged ink droplets of the second group of printing mechanisms located at the lower part are deflected upward. When the printed material is transported from left to right at high speed, the inkjet printer will reduce the voltage of the first positive voltage output electrode connected to the first positive electrode 112, and at the same time increase the voltage of the second positive voltage output electrode connected to the second positive electrode 113, so that the deflection direction of the ink droplets of the first group of printing mechanisms and the deflection direction of the ink droplets of the second group of printing mechanisms change to the right at the same time, so that the vertical columns of ink dots printed simultaneously by the first group of printing mechanisms and the second group of printing mechanisms can form a straight line. Similarly, when the printed material is transported from right to left at high speed, the inkjet printer will increase the voltage of the first positive voltage output electrode connected to the first positive electrode 112, and at the same time reduce the voltage of the second positive voltage output electrode connected to the second positive electrode 113, so that the deflection direction of the ink droplets of the first group of printing mechanisms and the deflection direction of the ink droplets of the second group of printing mechanisms change to the left at the same time, so that the vertical columns of ink dots printed simultaneously by the first group of printing mechanisms and the second group of printing mechanisms can form a straight line.

Embodiment 6:

This embodiment is similar to Embodiment 5, except that this embodiment is an application example of the present device in a dual-nozzle printhead of a reverse deflection type, as shown in FIG12 , a first positive electrode deflection plate 121 of a first printing mechanism and a second positive electrode deflection plate 125 of a second printing mechanism are respectively arranged on both sides of a common negative electrode deflection plate 124 of the first printing mechanism and the second printing mechanism, wherein a third positive electrode 122 and a fourth positive electrode 123 are arranged on the first positive electrode deflection plate 121, a fifth positive electrode 126 and a sixth positive electrode 127 are arranged on the second positive electrode deflection plate 125, the third positive electrode 122 and the fifth positive electrode 126 are both connected to the first positive voltage output electrode, the fourth positive electrode 123 and the sixth positive electrode 127 are both connected to the second positive voltage output electrode, the charged ink droplets of the first printing mechanism located at the upper part are deflected upward, and the charged ink droplets of the second printing mechanism located at the lower part are deflected downward. During printing, the conveying direction of the printed object, the printing speed, the voltage change mode of the first positive voltage output electrode and the second positive voltage output electrode, and the change mode of the ink droplet deflection direction are the same as the embodiment of the double-nozzle nozzle of the opposite deflection type in the above-mentioned embodiment 5, and the same beneficial effects are achieved.

Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims (1)

1. The multi-nozzle spray head is characterized by comprising a direction-changeable ink drop deflection device, wherein the direction-changeable ink drop deflection device comprises a nozzle (3), a charging electrode (4), a phase sensor (5), an electric field deflection area and a recovery groove (6) which are sequentially arranged, the electric field deflection area comprises a first deflection plate (1) and a second deflection plate (2) which are oppositely arranged, the first deflection plate (1) comprises a first electrode (11) and a second electrode (12), the first electrode (11) and the second electrode (12) are respectively arranged at two sides of an ink feeding direction, and the first electrode (11) and the second electrode (12) are connected with voltage output poles with different voltage magnitudes and same polarity; according to the actual transfer line moving speed and direction of the printed matter, the magnitude of the access voltage is adjusted so that the longitudinal column inclination of the ink points generated by the time difference of the ink drops reaching the printed matter is compensated by the change of the deflection direction of the ink drops to be eliminated;

The two second deflection plates (2) are respectively arranged at two sides of the first deflection plate (1);

or the two first deflection plates (1) are respectively arranged at two sides of the second deflection plate (2);

Or a plurality of the direction-changeable ink drop deflection devices are spliced together side by side to form a multi-nozzle spray head;

The first deflection plate (1) further comprises a resistor body (10), and the first electrode (11) and the second electrode (12) are respectively arranged at two ends of the resistor body (10); openings are respectively arranged at two ends of the resistor body (10), and the first electrode (11) and the second electrode (12) are respectively inserted into the openings; the first deflection plate (1) further comprises an insulating bottom plate (14), the first electrode (11) and the second electrode (12) are electrode layers (15) respectively coated at two ends of the insulating bottom plate (14), the insulating bottom plate (14) is further provided with a resistance layer (16), and the resistance layer (16) is respectively connected with the electrode layers (15) at two ends; the first deflection plate (1) is a positive electrode deflection plate; the resistor body (10) is one or a combination of a plurality of plastic, ceramic or resistor films.