A planar ink-permeating metal printing body, its preparation method, and a metal seal

Abstract

The present invention relates to the technical field of seals, and discloses a planar ink-permeable metal seal body and a preparation method thereof, and a metal seal. The metal seal body comprises a solid part, a font part formed by a through hole in the middle of the solid part, and a porous layer above the solid part and the font part; the font part and the porous layer are both porous structures formed by metal powder; and the seal face of the metal seal body is a plane composed of the solid part and the font part. In the present invention, the seal body seal face is a planar design, which has the effect of "hiding" characters, and is not afraid of being broken even if the seal face touches the ground, solving the problem of traditional metal seals being afraid of falling; by designing the metal seal body seal face font into a porous structure while the rest of the position remains a solid structure, the shortcomings of traditional seals that ink cannot be added and the stamping efficiency is slow are solved, while ensuring that the seal is hard and durable.

Description

Technical Field

[0001] The present invention relates to the technical field of seals, and in particular to a flat ink-permeating metal seal body, a preparation method thereof, and a metal seal. Background Art

[0002] As a thing for establishing credibility, seals have a vast market and applications in China. Seals are used by government agencies at the upper level and groups and individuals at the lower level. Seals can generally be divided into seals that can be continuously inked for stamping and seals that cannot be inked and need to be used with printing ink. Among them, copper seals are designated by the public security department as the special seal surface materials for government agencies, enterprise and institution official seals, bank record seals, etc. because of their advantages such as being hard and durable, having clear imprints, not being easily corroded by printing ink, and the seal surface never shrinking or deforming. However, traditional copper seals need to be used with printing ink and do not have an ink storage function, so the stamping efficiency is relatively low. At the same time, the font on the seal surface of traditional copper seals is set to protrude from the seal surface. When the seal surface touches the ground, it is easy to cause the font to wear and deform and become invalid, so it is especially afraid of being dropped.

[0003] Chinese Utility Model Patent with Publication No. CN 209336305 U discloses a new type of seal, including a shell, a pressing handle, a lid, a connecting top cover, a connecting shaft, a spring cover, a spring, an ink cartridge, a printing die, and a washer. After adjusting the seal mechanism, the seal surface can be pressed out of the shell to complete stamping, and it will automatically retract after releasing the hand. When not in use, the seal surface can be placed downward even without covering the lid. At the same time, the ink adding position is adjusted. The handle of the seal can be unscrewed, ink is injected through the through hole of the handle, and the ink enters the ink cartridge from the small oil injection hole. After being filled, the ink is not easy to leak out from the oil injection hole. Although this seal solves the problems of ink storage and ink injection, the font is still prone to wear and deformation and become invalid when the seal surface expands and contracts during use. Summary of the Invention

[0004] In order to solve the problem that metal seals cannot be inked and stamped repeatedly, and to ensure that the font is not easy to deform and wear, the present invention provides a flat ink-permeating metal seal body, a preparation method thereof, and a metal seal. The font is hidden in the solid metal, having the function of "hiding" the font, which can solve the problem that the font of traditional seals protrudes and is afraid of being dropped. The font is not easy to deform and wear; and the font part is a porous structure, having the functions of ink storage and ink permeation, improving the stamping efficiency.

[0005] The specific technical solution of the present invention is as follows:

[0006] In the first aspect, the present invention provides a flat ink-permeating metal seal body. The metal seal body includes a solid part, a font part formed by a through hole in the middle of the solid part, and a porous layer above the solid part and the font part; both the font part and the porous layer are porous structures formed by metal powders; the seal surface of the metal seal body is a plane composed of the solid part and the font part.

[0007] Traditional metal seals have the problem of not being able to add ink, and the stamping efficiency is low. Preparing a metal porous material seal body with uniform porosity is an effective way to realize the metal seal's ink storage and ink penetration functions. However, the porous material often has a hardness of only 30 to 40 HRC, low strength, and is not durable, and the font is easy to fall and deform. The present invention can enable the metal seal to have the functions of ink storage and ink penetration, while ensuring that it also has the advantage of not being easily deformed. The flat seal surface hides the font in solid metal, which has the function of "hiding" characters and can solve the problem of traditional seal fonts being prominent and afraid of falling. Moreover, only the font part is a porous structure, which can solve the problem of traditional copper seals not being able to add ink and having a slow stamping efficiency. The part other than the font is designed as a metal solid structure to ensure that the seal body has sufficient strength. Therefore, the flat metal seal body can be durable, improve the shortcomings of traditional metal seals, and maintain the advantage of not being easily deformed.

[0008] In a second aspect, the present invention provides a method for preparing a planar ink-permeable metal stamp body, comprising the following steps:

[0009] (1) Carving characters on the reverse side of a solid metal seal blank relative to the seal surface to form a metal seal blank with through holes for the characters;

[0010] (2) Filling the metal seal blank with the through holes of the font part with metal powder, placing the seal face downward in the mold, loosely filling the through holes with metal powder, and then pressing into a rough seal blank;

[0011] (3) Sintering the rough stamp body in an oxygen-free environment to obtain a planar ink-permeable metal stamp body.

[0012] The preparation of the planar ink-penetrating metal stamp body in the present invention includes: 1) engraving the reverse side of the traditional metal solid stamp body rough blank and forming the font through hole; the stamp body still maintains a solid structure except for the through hole position, ensuring that it also has the advantages of the traditional metal seal that is not easy to deform and has a certain strength; 2) selecting metal powder, loosely installing it into the above-mentioned through hole, and forming a metal porous structure through the loose installation, which has the functions of ink storage and ink penetration; 3) placing the above-mentioned rough blank in a sintering furnace, and controlling the atmosphere, temperature, time and other parameters to obtain a planar stamp body with a porous structure for the font instead of a solid structure at the font position. By filling the metal powder into the through hole and then sintering it with the solid structure, the sintering strength and bonding of the interface can be enhanced, and the resulting stamp body has the advantages of being hard and durable like a traditional copper seal, and the stamp surface will never shrink or deform.

[0013] The entire production process of the present invention does not involve environmental pollution problems such as acid and alkali wastewater, and at the same time, the seal body recovery rate is high, and the product is environmentally friendly.

[0014] Preferably, the pore diameter of the porous structure of the font part is 20-60 μm.

[0015] The pore diameter affects the ink storage and ink seepage efficiency. If the pore diameter is too large, it is difficult to control the ink seepage effect during stamping, and the ink seepage uniformity will deteriorate.

[0016] Preferably, in step (2), the loose metal powder is as follows: first, loose metal powder with a thickness of 1 - 2 mm and a particle size mesh number > 200 is loaded, and then loose metal powder with a particle size of 100 - 180 mesh is loaded for the remaining thickness at the through-hole position. Then, continue to load loose metal powder with a particle size of 100 - 180 mesh to form a porous layer with a thickness of 2 - 4 mm covering the solid part and the font part.

[0017] The particle size distribution and thickness of the loose metal powder affect the porous structure. When the particle size of the bottom layer is too large, it will affect the sintering adhesion effect and there is also a risk of ink leakage. Using gradient sintering with small particle size powder in the bottom layer and medium particle size powder in the upper layer is beneficial for uniform ink seepage without ink leakage, and the ink seepage effect is better. Moreover, the metal powder also affects the sintering stress and sintering strength during sintering. If the sintering interface between the metal powder and the solid part is not tight enough, it will also affect the ink seepage effect and produce burrs, affecting the product quality.

[0018] Forming a porous layer can improve the ink storage and ink seepage properties of the metal printing body, and contribute to the ink seepage uniformity of the through-hole part of the font. Also, the interfacial bonding between the metal powder and the solid part is better, and it will not damage the strength of the metal printing body, which remains hard and durable.

[0019] Preferably, in step (2), the pressing pressure is 50 - 200 MPa.

[0020] The pressing pressure can be controlled according to specific process parameter conditions.

[0021] Preferably, in step (1), the thickness of the metal solid seal blank is 2 - 3 mm; the cutting slope of the through-hole of the font part is 20 - 50°.

[0022] The cutting slope for reverse engraving is 20 - 50°, which can form a slope effect with a wider upper part and a narrower lower part, facilitating downward ink seepage and improving the stamping efficiency.

[0023] Preferably, in step (3), the non-oxygen sintering is: sintering at 650 - 980 °C for 40 - 150 min.

[0024] In a third aspect, the present invention also provides a metal seal, which includes the planar ink-seeping metal printing body as described in claim 1 or the planar ink-seeping metal printing body prepared by the preparation method as described in any one of claims 2 - 8.

[0025] Preferably, the metal seal further includes a shell; an elastic ink storage cotton and a planar ink-seeping metal printing body are sequentially arranged in the shell from top to bottom.

[0026] The metal stamp also includes a handle; the handle includes a pressing component and a connecting rod connected thereto; the connecting rod is connected to the shell by passing through a central opening above the shell.

[0027] The metal stamp also includes a sealing pad arranged above the elastic ink storage cotton; one end of the connecting rod is connected to the sealing pad, and a spring is arranged on the outer wall of the connecting rod. By applying pressure to a pressing component connected to the other end of the connecting rod, the spring squeezes the elastic ink storage cotton to achieve ink penetration. The built-in tension spring and cover design not only realizes repeated rebound stamping, but also has an overall installation positioning function.

[0028] The housing comprises an upper housing and a lower housing, wherein the elastic ink storage cotton and the flat ink-permeable metal stamp body are arranged in the lower housing; the upper housing and the lower housing are fastened by nuts. Therefore, the ink storage cotton can be easily disassembled and replaced, which greatly speeds up the ink filling efficiency and solves the problem of too slow ink filling efficiency of the ink storage stamp.

[0029] The metal stamp also includes a stamp box disposed below the housing; the stamp box is provided with elastic ink storage cotton. The stamp box matched with the stamp body is also provided with ink storage cotton, which can prevent accidental ink leakage and realize the recovery of leaked ink.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) The seal body is designed in a flat style, which is different from the traditional metal seal design where the font is protruding outside. It has the effect of "hiding" the font. Even if the seal touches the ground, it will not be damaged, thus solving the problem of traditional metal seals being afraid of being damaged.

[0032] (2) By designing the metal seal body and seal face fonts into a porous structure while the rest of the structure remains solid, the shortcomings of traditional seals, such as the inability to add ink and the slow stamping efficiency, are solved while ensuring that the seal is hard and durable;

[0033] (3) The metal seal improves the ink storage effect by setting elastic ink storage cotton, and is convenient for adding and replacing ink, thereby improving the stamping efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the structure of the metal seal in the present invention;

[0035] Figure 2 It is a schematic diagram of the "hidden characters" seal surface of the flat ink-permeable metal seal body in the present invention.

[0036] The reference numerals in the drawings are: pressing component 1, connecting rod 2, upper shell 3, spring 4, sealing gasket 5, elastic ink storage cotton I6, flat ink-permeable metal stamp body 7, stamp body box 8, elastic ink storage cotton II9, lower shell 10, nut I11, nut II12, shell cover 13. DETAILED DESCRIPTION

[0037] The present invention will be further described below in conjunction with embodiments. The devices, connection structures, and methods involved in the present invention are, unless otherwise specified, devices, connection structures, and methods well known in the art.

[0038] General Embodiment

[0039] 1. Planar Ink-Permeable Metal Stamp Body

[0040] The planar ink-permeable metal stamp body includes a solid part, a font part formed by a through-hole in the middle of the solid part, and a porous layer above the solid part and the font part. Both the font part and the porous layer are porous structures formed by metal powder. The pore diameter of the porous structure is 20 - 60 μm, and the plane composed of the solid part and the font part is the seal surface.

[0041] The preparation method of the above planar ink-permeable metal stamp body includes the following steps:

[0042] (1) Engrave the reverse side of a metal solid seal blank with a thickness of 2 - 3 mm relative to the seal surface to form a metal seal blank with a through-hole in the font part. The slope of the through-hole in the font part is 20 - 50°;

[0043] (2) Fill the metal powder into the through-hole in the font part of the metal seal blank. Place the seal surface downward in a mold, loosely fill the metal powder at the position of the through-hole, and then press it into a rough stamp body under a pressure of 50 - 200 MPa;

[0044] The loosely filled metal powder is: first loosely fill the metal powder with a thickness of 1 - 2 mm and a particle size mesh number > 200, and then loosely fill the metal powder with a particle size of 100 - 180 for the remaining thickness at the through-hole position;

[0045] Or, the loosely filled metal powder is: first loosely fill the metal powder with a thickness of 1 - 2 mm and a particle size < 250, then loosely fill the metal powder with a particle size of 100 - 180 for the remaining thickness at the through-hole position, and then continue to loosely fill the metal powder with a particle size of 100 - 180 to form a porous layer with a thickness of 4 - 6 mm covering the solid part and the font part.

[0046] (3) Sinter the rough stamp body in an oxygen-free environment, sinter at 650 - 980 °C for 40 - 150 min to obtain a planar ink-permeable metal stamp body.

[0047] 2. Metal Seal

[0048] The metal seal includes a shell, and an elastic ink storage cotton I6 and a planar ink-permeable metal stamp body 7 are sequentially arranged from top to bottom in the shell. The shell includes an upper shell 3 and a lower shell 10 fixedly connected by a nut I11, and the elastic ink storage cotton I6 and the planar ink-permeable metal stamp body 7 are arranged in the lower shell.

[0049] The metal seal also includes a handle. The handle includes a pressing member 1 and a connecting rod 2 connected thereto. The connecting rod 2 is connected to the housing through a central opening above the housing.

[0050] The metal seal also includes a gasket 5 provided above the elastic ink storage cotton I6. One end of the connecting rod 2 is connected to the gasket 5, and a spring 4 is provided on the outer wall of the connecting rod 2. By applying pressure through the pressing member 1 connected to the other end of the connecting rod 2, the spring 4 squeezes the elastic ink storage cotton I6 to achieve ink infiltration.

[0051] The metal seal also includes an impression body box 8 provided below the housing. An elastic ink storage cotton II9 is provided in the impression body box 8.

[0052] Embodiment 1

[0053] 1. Planar ink-infiltrating metal impression body

[0054] The preparation method of the planar ink-infiltrating metal impression body includes the following steps:

[0055] (1) Select an HMn58-2 brass cylinder with a diameter of 42 mm and a thickness of 3 mm as the solid metal seal blank. Use a CNC lathe to engrave characters on the reverse side relative to the seal face to form a metal impression body with through holes in the font part. The cutting slope of the through holes in the font part is 25°;

[0056] (2) Place the metal impression body with through holes in the font part in a mold with a diameter of 42 mm, with the seal face facing down. Loosely fill the metal powder at the position of the through holes. First, loosely fill 1 mm thick HMn58-2 brass powder with an average particle size of 220 mesh, and then loosely fill 4 mm thick HMn58-2 brass powder with an average particle size of 150 mesh; then apply a pressure of 150 MPa to press into a rough impression body blank;

[0057] (3) Carry out anaerobic sintering on the rough impression body blank (under an argon protection atmosphere), sinter at 750 °C for 60 min to obtain a planar ink-infiltrating metal impression body, as Figure 2 shown in the schematic diagram of the "hidden character" seal face of the planar ink-infiltrating metal impression body.

[0058] 2. Metal seal

[0059] As Figure 1 shown, the metal seal includes a housing, and an elastic ink storage cotton I6 and a planar ink-infiltrating metal impression body 7 are sequentially arranged from top to bottom in the housing. The housing includes an upper housing 3 and a lower housing 10 fixedly connected by a nut I11. The elastic ink storage cotton I6 and the planar ink-infiltrating metal impression body 7 are arranged in the lower housing.

[0060] The metal seal also includes a handle. The handle includes a pressing component 1 and a connecting rod 2 connected thereto. The connecting rod 2 is connected to the housing through a central opening above the upper housing 3. After passing through the connecting rod 2, a housing cover 13 is hermetically installed at the central opening above the upper housing 3 and fastened by a nut II 12. A sealing gasket 5 is provided above the elastic ink storage cotton I 6. One end of the connecting rod 2 is connected to the sealing gasket 5 and the other end is connected to the pressing component 1. A spring 4 is provided on the outer wall of the connecting rod 2. By applying pressure to the pressing component 1, the spring 4 squeezes the elastic ink storage cotton I 6 to achieve ink seepage.

[0061] Below the lower housing 10, there is an ink body box 8 for protecting the planar ink-seeping metal ink body 7. An elastic ink storage cotton II 9 is provided in the ink body box 8, which can not only prevent accidental ink leakage but also achieve ink leakage recovery.

[0062] The assembly steps of the metal seal are as follows: First, install the spring 4 into the corresponding preset groove of the connecting rod 2, then install the whole into the upper housing 3, and extend the upper end of the connecting rod 2 out of the central opening above the upper housing 3. The spring 4 is snap-fitted into the corresponding preset groove of the upper housing 3; then, hermetically install the housing cover 13 and fasten it with the positioning fastening nut II 12. Connect the pressing component 1 to the connecting rod 2 through an internal thread to complete the installation of the handle; then, install the sealing gasket 5, the elastic ink storage cotton I 6, and the planar ink-seeping ink body 7 into the lower housing 13 in the order from top to bottom; connect the upper housing 3 and the lower housing 13 through a card slot and fasten them with the positioning fastening nut I 11, thus completing the installation of the metal seal. In addition, by opening the positioning fastening nut I 11, it is possible to replace the elastic ink storage cotton, which is convenient for refilling and replacement.

[0063] Embodiment 2

[0064] The difference from Embodiment 1 is that the planar ink-seeping metal ink body is different.

[0065] The preparation method of the planar ink-seeping metal ink body includes the following steps:

[0066] (1) Select an HMn58-2 brass cylinder with a diameter of 42 mm and a thickness of 3 mm as the solid metal seal blank. Use a CNC lathe to engrave characters on the reverse side to form a metal ink body with through holes in the font part. The slope of the through holes in the font part is 25°;

[0067] (2) Place the metal ink body with through holes in the font part in a mold with a diameter of 42 mm, with the seal face facing down. Loosely fill the metal powder at the position of the through holes. First, loosely fill 2 mm thick HMn58-2 brass powder with an average particle size of 300 mesh, and then loosely fill 3 mm thick HMn58-2 brass powder with an average particle size of 150 mesh; then apply a pressure of 150 MPa to press it into a rough ink body blank;

[0068] (3) Carry out anaerobic sintering on the rough blank of the seal body (under an argon protection atmosphere), sinter at 790 °C for 60 min to obtain a planar ink-permeable metal seal body.

[0069] Example 3

[0070] The difference from Example 1 lies in: the planar ink-permeable metal seal body is different.

[0071] The preparation method of the planar ink-permeable metal seal body includes the following steps:

[0072] (1) Select an HMn58-2 brass cylinder with a diameter of 42 mm and a thickness of 3.5 mm as the solid metal seal blank, carry out reverse engraving through a CNC lathe to form a metal seal body with through holes in the font part, and the slope of the through holes in the font part is 30°;

[0073] (2) Place the metal seal body with through holes in the font part in a mold with a diameter of 42 mm, with the seal face facing down, loosely fill the metal powder at the position of the through holes. First, loosely fill HMn58-2 brass powder with a thickness of 2 mm and an average particle size of 300 mesh, and then loosely fill HMn58-2 brass powder with a thickness of 5 mm and an average particle size of 150 mesh; then apply a pressure of 100 MPa to press into a rough seal body;

[0074] (3) Carry out anaerobic sintering on the rough blank of the seal body (under an argon protection atmosphere), sinter at 760 °C for 90 min to obtain a planar ink-permeable metal seal body.

[0075] Example 4

[0076] The difference from Example 1 lies in: the planar ink-permeable metal seal body is different.

[0077] The preparation method of the planar ink-permeable metal seal body includes the following steps:

[0078] (1) Select an HMn58-2 brass cylinder with a diameter of 42 mm and a thickness of 3 mm as the solid metal seal blank, carry out reverse engraving through a CNC lathe to form a metal seal body with through holes in the font part, and the slope of the through holes in the font part is 25°;

[0079] (2) Place the metal seal body with through holes in the font part in a mold with a diameter of 42 mm, with the seal face facing down, loosely fill the metal powder at the position of the through holes. First, loosely fill HMn58-2 brass powder with a thickness of 1.5 mm and an average particle size of 250 mesh, and then loosely fill HMn58-2 brass powder with a thickness of 4.5 mm and an average particle size of 180 mesh; then apply a pressure of 100 MPa to press into a rough seal body;

[0080] (3) Carry out anaerobic sintering on the rough blank of the seal body (under an argon protection atmosphere), sinter at 760 °C for 90 min to obtain a planar ink-permeable metal seal body.

[0081] Comparative Example 1

[0082] The difference from Example 1 is that the metal powder is not gradient-loosely filled.

[0083] The preparation method of the planar ink-permeating metal seal body includes the following steps:

[0084] (1) Select a HMn58-2 brass cylinder with a diameter of 42 mm and a thickness of 3 mm as the metal solid seal blank, and use a numerical control lathe to engrave characters on the reverse side relative to the seal surface to form a metal seal body with through holes in the font part. The cutting slope of the through holes in the font part is 25°;

[0085] (2) Place the metal seal body with through holes in the font part in a mold with a diameter of 42 mm, with the seal surface facing down, and loosely fill the metal powder at the position of the through holes. Loosely fill HMn58-2 brass powder with a thickness of 5 mm and an average particle size of 160 mesh; then apply a pressure of 100 MPa to press it into a rough seal body;

[0086] (3) Carry out anaerobic sintering on the rough seal body (under an argon protection atmosphere), and sinter it at 790 °C for 60 min to obtain a planar ink-permeating metal seal body.

[0087] Comparative Example 2

[0088] The difference from Example 3 is that the parameters for gradient loose filling of the metal powder are different.

[0089] The preparation method of the planar ink-permeating metal seal body includes the following steps:

[0090] (1) Select a HMn58-2 brass cylinder with a diameter of 42 mm and a thickness of 3 mm as the metal solid seal blank, and use a numerical control lathe to engrave characters on the reverse side relative to the seal surface to form a metal seal body with through holes in the font part. The cutting slope of the through holes in the font part is 25°;

[0091] (2) Place the metal seal body with through holes in the font part in a mold with a diameter of 42 mm, with the seal surface facing down, and loosely fill the metal powder at the position of the through holes. First, loosely fill HMn58-2 brass powder with a thickness of 0.5 mm and an average particle size of 200 mesh, and then loosely fill HMn58-2 brass powder with a thickness of 4.5 mm and an average particle size of 150 mesh; then apply a pressure of 150 MPa to press it into a rough seal body;

[0092] (3) Carry out anaerobic sintering on the rough seal body (under an argon protection atmosphere), and sinter it at 600 °C for 90 min to obtain a planar ink-permeating metal seal body.

[0093] Comparative Example 3

[0094] The difference from Example 1 is that the cutting is vertical when engraving characters on the reverse side, and there is no cutting slope.

[0095] Preparation method of flat ink-permeable metal seal body, comprising the following steps:

[0096] (1) Select an HMn58-2 brass cylinder with a diameter of 42 mm and a thickness of 3 mm as the solid metal seal blank, and use a CNC lathe to engrave characters on the reverse side relative to the seal surface to form a metal seal body with through holes in the font part;

[0097] (2) Place the metal seal body with through holes in the font part in a mold with a diameter of 42 mm, with the seal surface facing downwards, loosely fill the metal powder at the position of the through holes. First, loosely fill HMn58-2 brass powder with a thickness of 1 mm and an average particle size of 220 mesh, and then loosely fill HMn58-2 brass powder with a thickness of 4 mm and an average particle size of 150 mesh; Subsequently, apply a pressure of 150 MPa to press into a rough seal body blank;

[0098] (3) Carry out anaerobic sintering on the rough seal body blank (under an argon protection atmosphere), sinter at 750 °C for 60 min to obtain a flat ink-permeable metal seal body.

[0099] Comparative Example 4

[0100] The difference from Example 1 is that the loose filling thickness of the porous layer is too small.

[0101] Preparation method of flat ink-permeable metal seal body, comprising the following steps:

[0102] (1) Select an HMn58-2 brass cylinder with a diameter of 42 mm and a thickness of 3 mm as the solid metal seal blank, and use a CNC lathe to engrave characters on the reverse side relative to the seal surface to form a metal seal body with through holes in the font part, and the cutting slope of the through holes in the font part is 25°;

[0103] (2) Place the metal seal body with through holes in the font part in a mold with a diameter of 42 mm, with the seal surface facing downwards, loosely fill the metal powder at the position of the through holes. First, loosely fill HMn58-2 brass powder with a thickness of 1 mm and an average particle size of 220 mesh, and then loosely fill HMn58-2 brass powder with a thickness of 2.6 mm and an average particle size of 150 mesh; Subsequently, apply a pressure of 80 MPa to press into a rough seal body blank;

[0104] (3) Carry out anaerobic sintering on the rough seal body blank (under an argon protection atmosphere), sinter at 750 °C for 45 min to obtain a flat ink-permeable metal seal body.

[0105] Table 1

[0106]

[0107] Table 2

[0108]

[0109] In Table 2, "the seal impression is clear, the border, characters, and graphics are intact without defects and pockmarks, and the seal code is clear" is defined as clear stamping.

[0110] In the present invention, the surface of the seal body is designed as a flat type, which is different from the design of traditional metal seals with protruding fonts, and has the effect of "hiding" the characters. Even if the seal surface touches the ground, it is not afraid of being damaged, solving the problem that traditional metal seals are afraid of being dropped. As can be seen from Table 1-2, by designing the font on the surface of the metal seal body into a porous structure while the remaining positions remain solid, the disadvantages of traditional seals that cannot be refilled with ink and have slow stamping efficiency are solved, while ensuring that the seal is hard and durable. Combining Example 1 and Comparative Examples 1-2, the loose packing of metal powder in the through holes is particularly important for the ink penetration effect. Non-gradient loose packing or too thin a dense layer at the bottom will affect the stamping of the seal. Combining Example 1 and Comparative Example 3, the reverse engraving has a certain cutting slope, and due to downward ink penetration, it can also avoid ink leakage and uneven stamping. Combining Example 1 and Comparative Example 4, if the loose packing thickness is too small, due to the subsequent pressing effect, the uniform ink penetration effect formed by the porous layer will become very weak, the ink penetration rate will slow down, and there will be residual ink between the ink storage cotton and the seal body, which cannot be fully utilized, reducing the stamping efficiency.

[0111] The above are only the preferred embodiments of the present invention and do not limit the present invention in any way. Any simple modifications, changes, and equivalent structural transformations made to the above embodiments according to the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A preparation method of a planar ink-permeating metal printing body, characterized in that, It includes the following steps: (1) Engrave the reverse side of the solid metal seal blank relative to the seal face to form a metal seal blank with through holes in the font part; (2) Fill the metal seal blank with through holes in the font part with metal powder, place the seal face down in the mold, first loosely fill 1 - 2 mm thick metal powder with a particle size mesh > 200, fill the remaining thickness at the through hole position with metal powder with a particle size of 100 - 180 mesh, and then continue to loosely fill metal powder with a particle size of 100 - 180 mesh to form a porous layer with a thickness of 2 - 4 mm covering the solid part and the font part, and then press it into a rough blank of the printing body; (3) Perform anaerobic sintering on the rough blank of the printing body to obtain a planar ink - permeable metal printing body.

2. The preparation method of the planar ink-permeable metal printing body according to claim 1, characterized in that, The planar ink - permeable metal printing body includes a solid part, a font part formed by through holes in the middle of the solid part, and a porous layer above the solid part and the font part; both the font part and the porous layer are porous structures formed by metal powder; the seal face of the metal printing body is a plane composed of the solid part and the font part.

3. The preparation method of the planar ink-permeating metal printing body according to claim 1, characterized in that The pore diameter of the porous structure of the font part is 20 - 60 μm.

4. The preparation method of the planar ink-permeable metal printing body according to any one of claims 1-3, characterized in that, In step (2), the pressure for pressing is 50 - 200 MPa.

5. The preparation method of the planar ink-permeating metal printing body according to claim 1, characterized in that, In step (1), the thickness of the solid metal seal blank is 2 - 3 mm; the cutting slope of the through hole in the font part is 20 - 50°.

6. The preparation method of the planar ink-permeating metal printing body according to claim 1 or 5, characterized in that, In step (3), the anaerobic sintering is: sintering at 650 - 980 °C for 40 - 150 min.

7. A metal seal, characterized in that, The metal seal includes a planar ink - permeable metal printing body prepared by the preparation method according to any one of claims 1 - 6.

8. The metal seal according to claim 7, characterized in that, The metal seal further includes a shell; an elastic ink - storage cotton and a planar ink - permeable metal printing body are sequentially arranged in the shell from top to bottom.

9. The metal seal according to claim 8, wherein The metal seal further includes a handle; the handle includes a pressing component and a connecting rod connected thereto; the connecting rod is connected to the shell through a central opening above the shell.

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