Energy-saving and noise-reducing printing head with weak electromagnetic eddy current

Abstract

According to the energy-saving and noise-reducing printing head with the weak electromagnetic eddy current, a unique printing needle arrangement method is adopted, 24 needles are asymmetrically grouped according to 8 needles and 16 needles, and through longitudinal offset of odd and even groups and precise transverse staggered layout, it is ensured that any two needles are in different columns, and the transverse distance is integer multiples of the non-standard dot distance; therefore, single-needle time sequence striking is achieved, noise superposition is avoided fundamentally, and peak current is reduced. In addition, an ingenious guide slide structure is further arranged to solve the problem of high-density needle threading, a cross groove is formed in a magnetic pole to restrain eddy current and reduce heating, and an arc chamfer is arranged at a needle tip to greatly reduce the current value. The printing head has the remarkable noise reduction and energy saving effects, the printing quality and the production efficiency are improved, and the multiple problems that in the prior art, printing noise is large, energy consumption is high, and color mixing is prone to occurring in double-color printing are effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of needle type printer, in particular to an energy-saving and noise-reducing print head with weak electromagnetic vortex. BACKGROUND

[0002] With the development of information technology, the demand for dual-color printing of needle type printers is increasing. One color is used to print documents, and the other color is used to print seals, which eliminates the need for additional seal printing. However, existing needle type printers have low printing efficiency, are prone to color mixing, have high noise, high energy consumption, and other shortcomings. The dual-color ribbon of the existing needle type printer includes two color zones, and the oil films of the two color zones penetrate each other to form an invalid printing color mixing zone. According to the characteristics of the ribbon base material and ink, the width of the color mixing zone is usually 0.4-0.7mm. In actual work, the width of the color mixing zone, the transverse fluctuation error of 0.25mm generated during the ribbon running, and the position deviation of about 0.1mm caused by the structural tolerance of the print head, the three types of errors are superimposed, which will cause the actual position and the theoretical position of the ribbon and the print head to deviate by a maximum of 0.95mm. This deviation range directly determines the minimum distance f between the two groups of needles in the print head responsible for printing two colors. Only when the minimum distance f is greater than 0.95mm, can the printing color mixing be avoided. However, the distance between the two groups of needles is not the larger the better. A larger distance will significantly increase the manufacturing cost of the print head, and even make it impossible to manufacture. At the same time, it will also increase the inclination angle of the printing needle, further increasing the difficulty of needle penetration, and consuming more manpower and electricity.

[0003] Red and black dual-color needle type printers are mainly used for printing documents and seals. Most of the printing content is one color, such as black, and the other color is only used for seal printing, such as red. This requires more needles for printing black and fewer needles for printing red, so that each group of needles is fully utilized and the efficiency is the highest. The existing dual-color printing technology allocates the same number of needles to two colors. The total number of printing needles in a print head is 24, which means that only 12 needles are used for printing more content, and the other 12 needles are used for printing less content, resulting in uneven distribution and low efficiency. In addition, the printing of red seals requires high quality and cannot allow color mixing. If the printing needle cannot avoid the color mixing zone, it will cause color pollution of the printed content, resulting in the rejection of the printed text or seal. If we try to reduce the red and black color mixing zone of the ribbon to alleviate the above problems, the manufacturing precision of the ribbon core and the viscosity control of the oil film will be greatly improved, which will greatly increase the manufacturing cost of the dual-color ribbon core. If we try to improve the precision of the printer structure to reduce the fluctuation error during the ribbon running, it will also greatly increase the cost of manufacturing the printer.

[0004] The needle arrangement of the conventional print head is in the same column in the longitudinal direction, and at least two print needles are arranged, so that when printing vertical lines, two or more print needles are simultaneously ejected, two or more needles are simultaneously generated, at least two electromagnetic coils are simultaneously charged, the peak current is superimposed to generate a larger peak current, and over-high energy consumption and heat are caused.

[0005] These technical bottlenecks cause the existing double-color needle printing technology to be difficult to simultaneously meet the needs of color mixing avoidance, noise control and energy efficiency optimization, and the specific performance is that unreasonable distribution of red and black print needles causes resource waste, and simultaneous ejection of multiple needles causes noise and energy consumption problems.

[0006] In addition, the print needle is very small in diameter, only 0.2-0.25 mm, and multiple spaced guide plates must be arranged to support the print needle to ensure that the print needle is not bent during printing. Each of the spaced guide plates has 24 needle holes for each print needle to pass through. Since the hole is very small and the guide plate is inside the print head, it is very difficult to install the print needle, and the needle insertion efficiency is low during production.

[0007] Finally, because the ejection and return actions of the print needle during printing are driven by the electromagnetic coil, the soft magnetic core of the electromagnetic coil generates a large eddy current during charging and discharging, causing a large heat generation. In addition, the back electromotive force generated by the eddy current also affects the charging current of the coil, thereby affecting the printing force.

[0008] The present application can effectively solve the problems of color mixing pollution, excessive noise and high energy consumption in the prior art through innovative print needle arrangement design and the addition of a slide structure. SUMMARY

[0009] In order to solve the above technical problems, the present application provides a weak electromagnetic eddy current energy-saving and noise-reducing print head.

[0010] A weak electromagnetic eddy current energy-saving and noise-reducing print head, comprising 24 print needles, the 24 print needles are divided into an upper end group and a lower end group; the upper end group is used for printing a first color, comprising an upper odd number group and an upper even number group, each group has 4 needles, and a total of 8 needles; the lower end group is used for printing a second color, comprising a lower odd number group and a lower even number group, each group has 8 needles, and a total of 16 needles; in the longitudinal direction of the print head, the upper even number group is offset downward as a whole compared with the upper odd number group in the longitudinal direction, the lower even number group is offset downward as a whole compared with the lower odd number group in the longitudinal direction, and the offset distances of the two are equal, the coordinate difference values of the adjacent two needle heads in each group in the longitudinal direction are equal, and are all 2 / 180 inches, which is defined as a; in the transverse direction of the print head, the transverse coordinate values of any two print needles are different, and the transverse spacings of any two print needles are not equal to an integer multiple of 1 / 180 inches.

[0011] Further, the difference between the vertical coordinates of the needle with the lowest vertical coordinate in the upper end group and the needle with the highest vertical coordinate in the lower end group is an integer multiple of 1 / 180 inch, and is 4.5-6.5 times of a.

[0012] Further, the needle numbers of the upper odd-numbered group are 1, 3, 5, and 7 from top to bottom, the needle numbers of the upper even-numbered group are 2, 4, 6, and 8 from top to bottom, the needle numbers of the lower odd-numbered group are 9, 11, 13, 15, 17, 19, 21, and 23 from top to bottom, and the needle numbers of the lower even-numbered group are 10, 12, 14, 16, 18, 20, 22, and 24 from top to bottom.

[0013] Further, in the sequence of the needle numbers 1, 3, 5, 7, 9, 11, the horizontal coordinates of the printing needles are sequentially decreased, and the coordinate difference of every adjacent two needle heads in the horizontal direction is equal; in the sequence of the needle numbers 13, 15, 17, 19, 21, 23, the horizontal coordinates of the printing needles are sequentially increased, and the coordinate difference of every adjacent two needle heads in the horizontal direction is equal; the horizontal coordinate of the needle number 11 is smaller than that of the needle number 13.

[0014] Further, in the sequence of the needle numbers 2, 4, 6, 8, 10, 12, the horizontal coordinates of the printing needles are sequentially increased, and the coordinate difference of every adjacent two needle heads in the horizontal direction is equal; in the sequence of the needle numbers 14, 16, 18, 20, 22, 24, the horizontal coordinates of the printing needles are sequentially decreased, and the coordinate difference of every adjacent two needle heads in the horizontal direction is equal; the horizontal coordinate of the needle number 12 is smaller than that of the needle number 14.

[0015] Further, the device further comprises a plurality of layers of guiding blocks arranged from top to bottom; each layer of guiding blocks comprises a guiding block one, a guiding block two, and a guiding block three, and each layer of guiding blocks is provided with a printing needle guiding plate, the printing needle guiding plate is provided with a needle hole for the printing needle to pass through, and the positions of the needle holes on each layer of printing needle guiding plates are different; each needle hole on each layer of printing needle guiding plates is provided with a guiding slide outside the entrance of the needle hole, one end of the guiding slide is smoothly connected to the side wall of the guiding block, and the other end naturally connects with the entrance of the needle hole.

[0016] Further, the device further comprises an electromagnet driving component, the electromagnet driving component comprises a ring-shaped electromagnet body, a plurality of magnetic poles with trapezoidal cross sections are arranged on one side of the electromagnet body, a coil is sleeved outside each magnetic pole, and a cross slot parallel to the axis direction of the coil is arranged in the center of each magnetic pole.

[0017] Further, the depth of the cross slot is greater than or equal to the height of the coil; one slot width dimension t1 of the cross slot is 2.5% of the sum of the bottom width X1 and the top width X2 of the cross section of the magnetic pole, i.e. t1=(X1+X2)×2.5%; and the other slot width dimension t2 is 5% of the height y1 of the cross section of the magnetic pole, i.e. t2=y1×5%.

[0018] Further, the printing tip of the printing needle is provided with a circular arc chamfer with a radius R, wherein 0.01mm≤R≤0.04mm.

[0019] Advantages of the present application: 1. The present application groups 24 needles in an asymmetric mode of 8+16, and through longitudinal offset of odd and even groups and precise transverse misalignment layout, ensures that any two printing needles are never in the same vertical column in the transverse direction, and the transverse spacing is not equal to an integer multiple of the standard minimum point distance (1 / 180 inch). Through this unique printing needle arrangement design, combined with single needle timing control, it is ensured that only a single needle strikes at any moment during printing, completely avoiding the problem of mechanical resonance and noise superposition caused by multiple needle impacts, with a significant noise reduction effect.

[0020] 2. The present application opens a cross slot on the magnetic pole of the electromagnet, which weakens the cancellation effect of eddy current on the magnetic field, ultimately improves the attraction force of the electromagnet, reduces the heating of the print head, and significantly reduces energy consumption.

[0021] 3. The present application optimizes the printing tip of the printing needle and adds a circular arc chamfer, effectively reducing the actual contact area of the needle tip and the printing medium, reducing the impact force required for single needle striking, and thus significantly reducing the driving current.

[0022] 4. The present application innovatively designs a guide slide structure outside the needle hole entrance of the multi-layer guide plate, which changes the traditional precise alignment to natural sliding. The operator only needs to make the needle head contact the slide slope surface, and the needle head can be automatically guided to the center of the needle hole and smoothly pass through under the gravity or light push, greatly reducing the technical requirements for the operator, greatly improving the production efficiency, and avoiding damage to the needle head or guide hole caused by repeated attempts to align. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor: Figure 1 Figure 1 is a printing needle arrangement diagram of the present application embodiment 1; Figure 2 Figure 2 is a needle arrangement diagram of two traditional print heads mentioned in the present application embodiment 1; Figure 3 Figure 3 is a print head cross-sectional view of the present application embodiment 2; Figure 4 Figure 4 is an enlarged view of the needle assembly of the present application embodiment 2; Figure 5 This is an enlarged view of the guide slide in Embodiment 2 of the present invention; Figure 6 This is a diagram showing the rounded chamfer of the printing tip of the printing needle in Embodiment 3 of the present invention; Figure 7 This is a cross-sectional view of the electromagnet in Embodiment 4 of the present invention; Figure 8 This is an enlarged view of the magnetic poles in Embodiment 4 of the present invention.

[0024] In the figure: needle assembly 100; armature 101; first guide block 201; second guide block 202; third guide block 203; printhead base 300; guide slide 400; rounded chamfer 500; cross groove 600. Detailed Implementation

[0025] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example 1

[0026] This embodiment provides an energy-saving and noise-reducing printhead with weak electromagnetic eddy currents.

[0027] Specifically, the present invention includes 24 printing needles, the printing tips of which are arranged within 24 small holes in a guide plate. In addition to the 24 small holes, a large positioning hole and a small positioning hole are provided in the center of the guide plate for mounting and positioning the guide plate.

[0028] like Figure 1 As shown, the printing needles of this invention are arranged in four groups: upper odd group, upper even group, lower odd group, and lower even group. The upper odd group and upper even group each have four needles; the lower odd group and lower even group each have eight needles.

[0029] To more clearly illustrate the arrangement of the printhead needles in this embodiment, the position coordinates (X, Y) of the 24 holes are described in detail below. See [link / reference] Figure 1 Using the line connecting the centers of the large and small positioning holes on the guide plate as the reference axis, and the midpoint of this line as the origin of the coordinate system, the Y-axis extends along the line connecting the centers of the two holes, and the X-axis is perpendicular to the Y-axis and extends to the right following the right-hand rule. The pinholes are arranged in four alternating groups: the upper odd-numbered groups are numbered 1, 3, 5, and 7; the upper even-numbered groups are numbered 2, 4, 6, and 8; the lower odd-numbered groups are numbered 9, 11, 13, 15, 17, 19, 21, and 23; and the lower even-numbered groups are numbered 10, 12, 14, 16, 18, 20, 22, and 24.

[0030] In which the upper odd array and the upper even array are located above the X axis, and are upper end groups, and the corresponding 8 needles are used to print red content, and the upper even array is offset by 1 / 180 inch (defined as parameter b) in the Y axis direction as a whole compared with the upper odd array; the lower odd array and the lower even array are located below the X axis and are lower end groups, and the corresponding 16 needles are used to print black content, and the lower even array is offset by 1 / 180 inch (same as parameter b) in the Y axis direction as a whole compared with the lower odd array; the above needle grouping is the 8+16 mode.

[0031] The following describes the longitudinal spacing (longitudinal arrangement relationship) between the print needle needle heads of the present application.

[0032] The double color ribbon of the existing needle printer contains two color zones, i.e. a first color zone and a second color zone, and the area formed by the penetration of the oil films of the two color zones together is a mixed color zone, which is an invalid printing area and directly affects the boundary precision of the printable area. According to a large amount of experimental data, it is proved that the width of the mixed color zone is generally 0.4-0.7 mm. During the working process of the color ribbon, the lateral offset amount is generated due to factors such as tension change, cooperation precision of the color ribbon running guide mechanism, etc., which leads to printing position drift, and the fluctuation error is 0.25 mm. The actual position of the print head and the theoretical position will be offset by 0.1 mm due to the tolerance of the print head itself and the tolerance of the print head mounting bracket. After the superposition of the above three types of errors, the maximum deviation range of the actual printing position and the theoretical design position when the color ribbon cooperates with the print head during the printing process can reach 0.95 mm, and the printing needle should avoid this area, otherwise the printing is easy to produce mixed color.

[0033] In the embodiment, the coordinate difference value of the adjacent two needle heads in each group on the Y axis is equal, and is 2 / 180 inch (defined as parameter a, a=2P), and the upper even array is offset by 1 / 180 inch as a whole in the Y axis direction compared with the upper odd array, which ensures that the spacing of the upper end group 1-8 needles in the y axis direction is 1 / 180 inch. The lower even array is offset by 1 / 180 inch as a whole in the Y axis direction compared with the lower odd array, which ensures that the spacing of the lower end group 9-24 needles in the y axis direction is 1 / 180 inch. This spacing setting conforms to the industry general standard of needle printers and meets the requirement that the minimum point distance of the needle print head in the vertical direction is 1 / 180 inch.

[0034] More specifically, the No. 8 needle of the upper even array is the needle with the lowest Y coordinate in the upper end group, the No. 9 needle of the lower odd array is the needle with the highest Y coordinate in the lower end group, the Y coordinate values of the No. 8 needle and the No. 9 needle are different by 1.267 mm, which is an integer multiple of 1 / 180 inch, and conforms to the standard of the paper feed step distance of the vertical motor of the needle printer, is 4.5 times of the Y axis direction spacing a (2 / 180 inch) of the adjacent needles in the same group, and 1.267-0.2=1.067 mm after removing the radius of the two needles, which is just greater than the color mixing deviation range 0.95 mm of the double color ribbon, so the printing needle arranged by the arrangement method of the application will not appear color mixing pollution in double color printing. It should be noted that the distance between the No. 8 needle with the lowest coordinate in the upper end group and the No. 9 needle with the highest Y coordinate in the lower end group is not greater than 6.5 times of a, otherwise the needle guide plate of the print head will be too dispersed in the needle hole, which will greatly increase the manufacturing cost, and at the same time will require to increase the width of the ribbon.

[0035] The horizontal spacing (horizontal arrangement relationship) between the printing needle needles of the application will be described below.

[0036] The lateral spacing between the printing needles is as follows: the printing resolution of the 24-needle needle printer is 180 DPI (dots per inch), the minimum dot distance between the printed dots is 1 / 180 inch, which is represented by P, i.e. P = 1 / 180 inch. In the sequence of needle numbers 1, 3, 5, 7, 9, 11, the lateral coordinates of the printing needles decrease in turn, the longitudinal coordinates decrease in turn, and the coordinate difference of every adjacent two needle heads on the X axis is equal, which is 7 / 12×P. In the sequence of needle numbers 2, 4, 6, 8, 10, 12, the lateral coordinates of the printing needles increase in turn, the longitudinal coordinates decrease in turn, and the coordinate difference of every adjacent two needle heads on the X axis is equal, which is 7 / 12×P. In the sequence of needle numbers 13, 15, 17, 19, 21, 23, the lateral coordinates of the printing needles increase in turn, the longitudinal coordinates decrease in turn, and the coordinate difference of every adjacent two needle heads on the X axis is equal, which is 7 / 12×P. In the sequence of needle numbers 14, 16, 18, 20, 22, 24, the lateral coordinates of the printing needles decrease in turn, the longitudinal coordinates decrease in turn, and the coordinate difference of every adjacent two needle heads on the X axis is equal, which is 7 / 12×P. More specifically, the left side of the Y axis is 12 odd-numbered needles, and the right side of the Y axis is 12 even-numbered needles. In order to make the lateral distance between every two dots not be an integer multiple of P, the lateral distance between adjacent needles should be (k / 12)×P, k is a non-zero natural number, k and 12 have no common divisor, and in order to make the volume of the printing head as small as possible, it is required that k is less than 12, so k can only be 5, 7 or 11. In this example, k = 7 is taken as an example. The X coordinate of the 1st needle is smaller than that of the 23rd needle by 1 / 12P, and the X coordinate of the 3rd needle is smaller than that of the 21st needle by 1 / 12P, the X coordinate of the 5th needle is smaller than that of the 19th needle by 1 / 12P, the X coordinate of the 7th needle is smaller than that of the 17th needle by 1 / 12P, the X coordinate of the 9th needle is smaller than that of the 15th needle by 1 / 12P, and the X coordinate of the 11th needle is smaller than that of the 13th needle by 1 / 12P. The X coordinate of the 2nd needle is smaller than that of the 24th needle by 1 / 12P, and the X coordinate of the 4th needle is smaller than that of the 22nd needle by 1 / 12P, the X coordinate of the 6th needle is smaller than that of the 20th needle by 1 / 12P, the X coordinate of the 8th needle is smaller than that of the 18th needle by 1 / 12P, the X coordinate of the 10th needle is smaller than that of the 16th needle by 1 / 12P, and the X coordinate of the 12th needle is smaller than that of the 14th needle by 1 / 12P. That is, no two needles are arranged in the same column in the longitudinal direction. This progressive arrangement makes all the printing needles form an accurate staggered layout in the X axis direction, which not only ensures the printing resolution requirement, but also realizes complete single-needle timing control.

[0037] The printing head moves horizontally during printing, and each needle moves to the position where printing is required. When one needle is ejecting, no other needle is simultaneously present at the pixel position to be printed, because the resolution of the pixel to be printed is 180 dpi (dots per inch), and no other needle is simultaneously ejecting. The printing is staggered, which maximally avoids noise superposition caused by multiple needles ejecting simultaneously, and maximally reduces noise.

[0038] The traditional printing head needle arrangement is divided into two types. One is that the printing needles are arranged at equal intervals in the longitudinal direction, as shown in the left part of Fig. 1. This distribution does not divide the printing needles into two groups, and thus cannot avoid the color mixing area of the double-color ribbon, and cannot solve the problem of double-color printing. In addition, there are 2 or more needles in each column, which will cause two or more needles in the same column to eject simultaneously when printing vertical lines, resulting in noise superposition and increasing noise. Figure 2 The second is to divide the printing needles into two groups, and the number of needles in each group is equal, i.e., 12+12 mode, as shown in the right part of Fig. 1. This arrangement will cause low printing efficiency. As described above, the red and black double-color printing is mainly used for documents and seals, and the black part prints documents and the red part prints seals. The content of the black part is more than that of the red part. It is obviously unreasonable to evenly divide the printing needles for printing black and red content. In addition, the number of red printing needles is too large, far exceeding the actual demand, which will increase standby energy consumption when idle, and consume additional power when working without full load, causing waste of electric energy.

[0039] Figure 2 Therefore, the needle arrangement of the traditional printing head will arrange at least 2 printing needles in the same column in the vertical direction. When printing vertical lines or black blocks, at least 2 needles will eject simultaneously. On the one hand, the printer will produce noise when working, and at least 2 or more printing needles will produce superimposed impact sound. On the other hand, when 2 or more printing needles are in the same driving sequence, the electromagnetic coil needs to withstand the superimposed peak current, which will increase the load of the power supply.

[0040] The present application adopts a more efficient method, i.e., the number of printing needles for printing the black part is divided into more, and the number of printing needles for printing the red part is divided into less. This maximally improves the efficiency and saves unnecessary resource consumption. This asymmetric grouping brings great difficulty to the needle threading during the production of the printing head, but the present application solves this problem, as shown in the guiding slide structure of Example 2.

[0041]

[0042] ​​In summary, the 24-needle print head of the present application ensures that all needle holes meet two key conditions when printing laterally reciprocatingly: first, any two needles are never in the same vertical column in the X-axis direction, that is, the X-coordinate values of any two needles are not the same, which requires a more complex software control algorithm to achieve print control; second, the lateral spacing of any two needles is not an integer multiple of 1 / 180 inch (about 0.141 mm). The present application groups 24 needles into asymmetric groups of 8 and 16, and through longitudinal offset of odd and even groups and precise lateral misalignment layout, ensures that any two needles are in different columns and the lateral spacing is not an integer multiple of the standard point distance. This unique arrangement ensures that only a single needle strikes at any time during printing. Since the needle positions are completely staggered and the spacing is precisely calculated, it is impossible for two or more needles to eject at the same time, that is, only one point is ejecting at any instant. This effectively avoids the noise superposition of mechanical resonance caused by multiple needle impacts, and the actual measurement can reduce the working noise by 10 dB. The noise of an ordinary printer is below 60 dB, while the noise of a print head using the present application can be below 50 dB.

[0043] To achieve the printing action, the print head is individually configured with an electromagnet drive for each printing needle, that is, 24 electromagnets. The maximum peak current of each electromagnet can reach 1.6 A during printing. If multiple needles eject at the same time, multiple electromagnets will be charged at the same time, and the peak current is cumulative. The peak current of 2 needles is twice that of a single needle, and so on. The peak current of multiple needles is close to multiple times. The more coils that are charged at the same time, the greater the peak current, which requires a larger switching power supply and greater power consumption. The present application uses precise needle arrangement design and timing control. At any printing moment, the present application only has a single needle for striking action, that is, only one electromagnet is powered on. This single needle sequential striking consumes less peak current than the multiple needle simultaneous striking that can occur in traditional designs, requiring a lower power supply. Therefore, it is more energy-efficient, reducing overall energy consumption. The switching power supply power of a similar needle printer needs about 65 W, while the switching power supply power of a printer using the present application needs less than 50 W, reducing the heat generated by the power supply circuit. Example 2

[0044] This embodiment provides a weak electromagnetic eddy current energy-saving and noise-reducing print head, as shown in Figure 3 、 Figure 4The printhead is composed of an upper half, a lower half and other accessories. The upper half is an electromagnet driving part, and the lower half is composed of a printhead base 300, 24 needle assemblies 100 and three layers of guide blocks. The needle assembly 100 is composed of a printing needle and an armature 101. The printing needle is welded at the tip of the armature 101 at a certain angle. The needle assembly 100 is distributed in a ring shape. The armature 101 is supported on the printhead base 300. The printing needle is fixed through the three layers of guide blocks, i.e., a first guide block 201, a second guide block 202 and a third guide block 203. Each layer of guide block is provided with a guide slide 400. The bottom of the guide slide 400 is a printing needle guide plate. The printing needle guide plate is provided with 24 holes. The positions of the needle holes on each layer of printing needle guide plate are different. The 24 printing needle tips pass through the three layers of printing needle guide plates in turn, and finally form the needle tip arrangement mode shown in Embodiment 1.

[0045] More specifically, referring to Figure 5 The outer side of each hole of each printing needle guide plate is provided with a guide slide 400. One end of the guide slide 400 is smoothly connected to the side wall of the guide block, and the other end is naturally connected with the entrance of the needle hole. The cross section of the guide slide 400 is in the form of an arc with a high edge and a low middle.

[0046] In the prior art, the printing needle of the printhead is designed to be long and thin to meet the requirement of 180 dpi resolution ratio. During work, the printing needle needs to pass through the needle holes on multiple layers of guide plates to limit the bending deformation of the printing needle caused by force during printing. There are 24 needle holes on each guide plate. The diameter of the needle hole is only 0.02-0.04 mm larger than the diameter of the printing needle. At the same time, due to the requirement of printing needle arrangement density, the positions of the needle holes on each layer of guide plate are different, and the wall thickness between adjacent needle holes is very small. The smallest wall thickness between holes is only 0.05 mm. This design causes the traditional guide plate to be unable to set a large guide angle at the entrance of the needle hole. On the one hand, the wall thickness is too small to be machined. On the other hand, a too large guide angle will affect the adjacent holes. This makes the needle insertion operation face two big problems. Firstly, the printing needle is long and thin, which is difficult to accurately position. Secondly, the alignment requirement of the needle hole and the needle tip is very high. Therefore, the traditional printhead cannot realize automatic needle insertion, and the needle insertion is performed manually, which requires high skill of the operator and is low in efficiency.

[0047] The guiding slide structure designed by the present application ingeniously solves this pain point. During the needle threading process, the operator does not need to deliberately align the needle head and the needle hole. When the needle head of the printing needle contacts the guiding slide slope surface, the needle head will be naturally guided into the needle hole by the guiding slide slope surface, greatly reducing the difficulty of needle threading operation and greatly improving the efficiency of needle threading. The design of the present application is ingenious and practical, and the cost is controllable, the processing difficulty is moderate, the processing does not require complex process, and the present manufacturing equipment can be relied on to realize it without increasing the production cost. The combination mode of the structure form and the guiding plate body is scientific and reasonable, and does not require higher requirements for the overall strength of the guiding plate and the accuracy of the needle hole. Therefore, the processing difficulty is controllable, and it is easy to realize large-scale production and application. Example 3

[0048] In this embodiment, the printing tip of the printing needle is optimized and designed. Specifically, a circular arc chamfer 500 (with a radius of R) is added to the printing tip of the needle, as shown in Figure 6 .

[0049] The copy force of the needle type printing head is proportional to the pressure intensity applied by the printing needle to the paper. The diameter of the printing needle is d, the impact force of the printing needle is f, and the area of the tip is s. The tip pressure p can be expressed as p=f / s. Under the premise that the needle diameter d is constant, the addition of the circular arc chamfer 500 to the tip can effectively reduce the area s of the tip. Under the premise of ensuring the same copy force, i.e., pressure p, the required printing needle impact force f is smaller.

[0050] Specifically, the present application provides a needle printing tip with a circular arc chamfer 500 with a radius R, wherein 0.01mm≤R≤0.04mm, and the circular arc chamfer 500 is formed by automatic vibration polishing. Taking a printing needle with a diameter of 0.2mm as an example, the area of the tip without the circular arc chamfer 500 is 0.1 2 ×3.14159=0.03142mm 2 The area of the tip with a circular arc chamfer with a radius of R0.01 is (0.1-0.01) 2 ×3.14159=0.02545mm 2 Under the premise of keeping the diameter d of the printing needle unchanged, the printing contact area is reduced to 81% of the original area, i.e., 0.02545 / 0.03142×100%=81%. Under the premise of ensuring the pressure intensity, the impact force f of the printing needle is reduced by 19%. The impact force of printing is generated by the charging of the electromagnetic coil. According to the formula F=(μ0 μᵣ N² I² S) / (4 L²), it can be seen that the suction force is proportional to the square of the coil current. The suction force is reduced by 19%, and the current is reduced by the square root of 19%, i.e., 43.6%, which greatly reduces the current value and reduces the energy consumption.

[0051] The meanings of the variables of the formula F=(μ0 μᵣ N² I² S) / (4 L²) of the attracting force of the electromagnet are shown in the following table:

[0052] It should be noted that the circular arc chamfering of the needle tip of the present application only changes the shape of the needle tip, and does not make the whole needle thin, so it will not affect the firmness of the needle, will not reduce the strength of the printing needle, will not affect the printing effect, and will not affect the durability of the needle. Example 4

[0053] In this embodiment, the magnetic poles of the electromagnet of the print head are innovatively designed. The electromagnet body of the print head is an annular part, and 24 magnetic poles with trapezoidal cross sections are annularly distributed on one side surface of the electromagnet body. The outer side of the magnetic poles is sleeved with a coil to form 24 electromagnets for generating a printing driving force. Since the magnetic poles of the print head are solid, the charging and discharging frequency of the electromagnet inside the print head during printing is as high as 2400 Hz, which belongs to a high-frequency electromagnet. During the high-frequency charging and discharging process of the coil, eddy current is generated, thereby generating a relatively large heat, increasing energy consumption, and the eddy current generates an "opposite magnetic field" opposite to the original magnetic field direction, which has a macro effect equivalent to generating an opposite electromotive force at both ends of the magnetic coil. The opposite electromotive force will prevent the charging and discharging rate of the electromagnetic coil, thereby reducing the attracting force of the electromagnet.

[0054] As shown in Figure 7 , Figure 8 , the present application is provided with a cross slot 600 parallel to the axis direction of the coil in the central part of the magnetic pole. The depth h2 of the cross slot 600 is greater than or equal to the height h1 of the coil, and the vertical slot width size t1 is 2.5% of the sum of the width X1 of the bottom of the trapezoidal cross section of the magnetic pole and the width X2 of the top, that is, (X1+X2)×2.5%, and the horizontal slot width size t2 is 5% of the height y1 of the trapezoidal cross section of the magnetic pole. It should be noted that this ratio cannot be smaller, otherwise the part cannot be manufactured. In this way, the cross-sectional area of the magnetic pole is reduced by 5%. According to the formula F=(μ0 μᵣ N² I² S) / (4 L²) of the attracting force of the electromagnet, the attracting force of the electromagnet is proportional to the cross-sectional area of the magnetic core attracting surface, and the theoretical attracting force will decrease by 5%. The cross slot 600 divides the magnetic pole into four parts in the longitudinal direction, effectively suppressing the strength of the eddy current, and the energy consumption generated by the eddy current is reduced by about 20% in actual measurement. The influence of the counter electromotive force generated by the eddy current on the attracting force of the electromagnet is about 8%. Although the increased slotting reduces the attracting force of the electromagnet by 5%, the influence of the counter electromotive force generated by the eddy current on the attracting force is reduced by 8%, and finally the attracting force of the electromagnet is not affected but increased by about 3%, and the heat generation is reduced by 20%, thereby greatly reducing the energy consumption.

[0055] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and are not to be construed as limiting the present application, and that changes, modifications, substitutions and variations can be made by those skilled in the art without departing from the scope of the present application.

Claims

1. An energy-saving and noise-reducing printhead with weak electromagnetic eddy currents, characterized in that, It includes 24 printing pins, which are divided into upper and lower groups; The upper group is used to print the first color, including an upper odd group and an upper even group, with 4 needles in each group, for a total of 8 needles; The lower group is used for printing the second color, including the lower odd group and the lower even group, with 8 needles in each group, for a total of 16 needles; In the longitudinal direction of the printhead, the upper even array is offset downwards as a whole compared to the upper odd array, and the lower even array is offset downwards as a whole compared to the lower odd array. The offset distances of the two arrays are equal, and the coordinate difference between two adjacent needles in each array is equal, which is 2 / 180 inch, defined as a. In the horizontal direction of the printhead, the horizontal coordinate values ​​of any two print pins are not the same, and the horizontal distance between any two print pins is not an integer multiple of 1 / 180 inch.

2. The energy-saving and noise-reducing printhead with weak electromagnetic eddy currents according to claim 1, characterized in that, The difference in longitudinal coordinate between the needle with the lowest longitudinal coordinate in the upper group and the needle with the highest longitudinal coordinate in the lower group is an integer multiple of 1 / 180 inch, which is 4.5 to 6.5 times that of a.

3. The energy-saving and noise-reducing printhead with weak electromagnetic eddy currents according to claim 2, characterized in that, The stitch numbers of the upper odd group are 1, 3, 5, and 7 from top to bottom; the stitch numbers of the upper even group are 2, 4, 6, and 8 from top to bottom; the stitch numbers of the lower odd group are 9, 11, 13, 15, 17, 19, 21, and 23 from top to bottom; and the stitch numbers of the lower even group are 10, 12, 14, 16, 18, 20, 22, and 24 from top to bottom.

4. The energy-saving and noise-reducing printhead with weak electromagnetic eddy currents according to claim 3, characterized in that, In the sequence of needle numbers 1, 3, 5, 7, 9, 11, the horizontal coordinates of the printing needles decrease sequentially, and the difference in horizontal coordinates between any two adjacent needles is equal. In the sequence of needle numbers 13, 15, 17, 19, 21, and 23, the horizontal coordinates of the printing needles increase sequentially, and the difference in horizontal coordinates between any two adjacent needles is equal. The horizontal coordinate of needle number 11 is smaller than that of needle number 13.

5. The energy-saving and noise-reducing printhead with weak electromagnetic eddy currents according to claim 3, characterized in that, In the sequence of needle numbers 2, 4, 6, 8, 10, and 12, the horizontal coordinates of the printing needles increase sequentially, and the difference in horizontal coordinates between any two adjacent needles is equal. In the sequence of needle numbers 14, 16, 18, 20, 22, and 24, the horizontal coordinates of the printing needles decrease sequentially, and the difference in horizontal coordinates between any two adjacent needles is equal. The horizontal coordinate of needle number 12 is smaller than that of needle number 14.

6. The energy-saving and noise-reducing printhead with weak electromagnetic eddy currents according to any one of claims 1 to 5, characterized in that, It also includes multi-layered guide blocks arranged from top to bottom; The multi-layer guide block includes guide block one, guide block two and guide block three from top to bottom. Each layer of guide block is provided with a printing needle guide plate. The printing needle guide plate has a needle hole for the printing needle to pass through, and the position of the needle hole on each layer of printing needle guide plate is different. On each layer of the printing needle guide plate, a guide slide is provided on the outside of the entrance of each needle hole. One end of the guide slide is smoothly connected to the side wall of the guide block, and the other end is naturally connected to the entrance of the needle hole.

7. The energy-saving and noise-reducing printhead with weak electromagnetic eddy currents according to claim 6, characterized in that, It also includes an electromagnet driving component, which includes an annular electromagnet body. Multiple magnetic poles with trapezoidal cross-sections are distributed annularly on one side of the electromagnet body. A coil is sleeved on the outside of each magnetic pole, and a cross groove parallel to the axis of the coil is provided in the center of each magnetic pole.

8. The energy-saving and noise-reducing printhead with weak electromagnetic eddy currents according to claim 7, characterized in that, The depth of the cross groove is greater than or equal to the height of the coil; The width t1 of the cross groove is 2.5% of the sum of the base width X1 and the top width X2 of the trapezoidal cross section of the magnetic pole, i.e., t1 = (X1 + X2) × 2.5%; Another slot width dimension t2 is 5% of the trapezoidal height y1 of the magnetic pole cross section, that is, t2 = y1 × 5%.

9. The energy-saving and noise-reducing printhead with weak electromagnetic eddy currents according to any one of claims 1 to 5, characterized in that, The printing needle has a rounded chamfer with a radius of R at the tip of the printing tip, where 0.01mm≤R≤0.04mm.

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