Anti-leakage pen point and needle tube refill

Abstract

The utility model provides an anti-leakage pen point and a needle tube refill, and belongs to the technical field of writing tool components. The pen point comprises a ball bead, a ball seat body and a spring; the ball seat body is in a hollow tube shape and is provided with a bowl seat for supporting the ball, an inner hole is formed in the center of the bowl seat, the ball is embedded in the bowl seat and the inner hole, the spring is arranged in the ball seat body and is provided with an ejector pin, and the ejector pin abuts against the ball through the inner hole. Oil grooves are machined in the bowl base through a groove punching tool, distributed in the front end of the bowl base and in contact with the ball, and the oil grooves are not directly communicated with the inner hole. The design of the bowl base and the inner hole structure has a larger pressure bearing area, is matched with the spring structure and is not prone to shaking, ink is stably discharged from the pen point, and the abrasion resistance is improved. The design that the oil groove is not directly communicated with the inner hole can prevent the spring from being stuck, reduce ink dripping and accumulation and control the ink outlet amount.

Description

Technical Field

[0001] The utility model relates to a leakage-proof pen head and a needle tube pen core, belonging to the technical field of writing tool parts. Background Art

[0002] Since its introduction, ballpoint pens have brought great changes to the development of writing tools. From the earliest ink ballpoint pens to the later water-based ink ballpoint pens and gel ink ballpoint pens, as market demand changes, ballpoint pens have made leaps and bounds as a new generation of writing tools, and consumers have put forward higher requirements for the functions and applicability of products.

[0003] Consumers, especially students, are more looking for needle-tube refills with finer nibs. The pen tips used in these needle-tube refills are characterized by thin nib diameters and narrow writing lines. Due to the above characteristics, the technical requirements for the spring embedded in the pen tip are relatively high. Therefore, for a long time, needle-tube neutral pen refills only have plug-in cap products, and no push-type products.

[0004] CN102848793B provides a wire-type needle spring pen tip, which is made by cutting HV240-280 wire, solving the problem that the needle pen tip cannot be used in a push-type pen. Due to material and structural limitations, this pen tip has a certain proportion of problems such as easy spring deviation, needle tip jamming, bowl mouth separation, and ink leakage, and its material cost is relatively high. Utility Model Content

[0005] In order to solve the problems of ink leakage and high material cost of the existing needle spring pen tip, the utility model combines various technical advantages and provides the following technical solutions:

[0006] A leakage-proof pen tip comprises a ball 1, a ball seat body 2 and a spring 3. The ball seat body 2 is hollow and tubular and has a bowl seat 22 for supporting the ball 1. The center of the bowl seat 22 has an inner hole 24. The ball 1 is embedded in the bowl seat 22 and the inner hole 24. The spring 3 is inside the ball seat body 2. The spring 3 has an ejector pin 31. The ejector pin 31 pushes on the ball 1 through the inner hole 24. The bowl seat 22 is processed into an oil groove 21 by a groove punching tool 5. The oil groove 21 is distributed at the front end of the bowl seat 22 and contacts the ball 1. The oil groove 21 is not directly connected to the inner hole 24, and the oil groove 21 is not connected to the pit 23.

[0007] Furthermore, the bowl seat 22 is processed into a recess 23 at the front end of the ball seat body 2 by a pressing tool 4 , and the recess 23 protrudes from the inside of the ball seat body 2 to form the bowl seat 22 .

[0008] Further, the number of the pits 23 is in the range of 2-8, and the shapes include one or more combinations of circle, oval, triangle, square or pentagon.

[0009] Further, the number of the oil grooves 21 is in the range of 2-8, and the shapes include one or more combinations of circular, elliptical, triangular, square or pentagonal.

[0010] Furthermore, a small hole 26 is provided at the end of the ball seat body 2; the spring 3 also includes a front parallel circle 32, an effective circle 33 and a rear parallel circle 34. The front parallel circle 32 is located at the front end of the spring 3 and connects the ejector pin 31 and the effective circle 33. The rear parallel circle 34 is located at the end of the spring 3 and contacts the small hole 26. The inner and outer diameters of the front parallel circle 32, the effective circle 33 and the rear parallel circle 34 are the same, so that the ink flow rate remains uniform.

[0011] Furthermore, the ball seat body 2 includes a spring positioning point 25 , which is used to fix the spring 3 . The spring positioning point 25 is located at the connection between the small hole 26 and the rear parallel circle 34 and is formed by a slot punching tool 5 .

[0012] Furthermore, the diameter of the ball 1 is in the range of 0.3-0.8 mm; the ball 1 is a hard alloy ball or a ceramic ball.

[0013] Furthermore, the material of the ball seat body 2 is a stainless steel pipe, the outer diameter of the stainless steel pipe is in the range of 0.7-1.2 mm, and the stainless steel is one of 304, 304L, 316 or 316L.

[0014] The utility model also provides an anti-leakage needle tube pen core, comprising a pen core tube body, ink and any of the above anti-leakage nibs, the anti-leakage nib is located at the front end of the pen core tube body, the pen core tube body has a tubular cavity connected to the small hole 26, the cavity is used to contain ink; the ink is one of neutral ink, water-based ink or emulsified ink.

[0015] The utility model has the following beneficial effects:

[0016] 1. The ball seat adopts a solution of a whole section of convexity to form a bowl seat, which has a larger pressure-bearing area design space, and controls the balance between ink discharge and pressure through secondary processing tools, so that the pen tip has better wear resistance and more stable ink discharge ability.

[0017] 2. The structural design that the oil groove is not directly connected to the inner hole can prevent the spring from getting stuck, reduce ink dripping, and control the amount of ink output; the inner hole structure of the ball seat is well adapted to the spring, is not easy to shake, and the ink output is more stable and the hand feel is better.

[0018] 3. The pen tip is made of stainless steel pipe. Compared with the wire-type pen tip, it has low material cost, low processing difficulty and better environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a front schematic diagram of the utility model;

[0021] Figure 2 This is a schematic diagram of the cross-sectional structure of the utility model;

[0022] Figure 3 This is a partial enlarged schematic diagram of the bowl seat of the utility model;

[0023] Figure 4 This is a schematic diagram of the oil tank structure from a top view of the utility model;

[0024] Figure 5 This is a front view of the spring of the utility model;

[0025] Figure 6 This is a front view schematic diagram of the pressure point cutter of the utility model;

[0026] Figure 7 This is a top view of the pressure point cutter of the utility model (the blade portion);

[0027] Figure 8 This is a front view of the slot punching tool of the utility model;

[0028] Fig. 9 It is a top view of the slot punching tool of the utility model (punch part).

[0029] The reference numerals are described as follows:

[0030] 1: Balls

[0031] 2: Ball seat

[0032] 21: Oil tank

[0033] 22: Bowl seat

[0034] 23: Pit

[0035] 24: Inner hole

[0036] 25: Spring positioning point

[0037] 26: Small hole

[0038] 3: Spring

[0039] 31: Ejector

[0040] 32: Forward Circle

[0041] 33: Effective circle

[0042] 34: Back and forth

[0043] 4: Pressure point tool

[0044] 41: Press down the cutter head

[0045] 42: Pressure point blade

[0046] 5: Slot punch tool

[0047] 51: Small hole punch

[0048] 52: Oil groove punch

[0049] 53: Groove the blade. DETAILED DESCRIPTION

[0050] The detailed features and advantages of this patent are described in detail in the specific implementation method below, and the content is sufficient to enable any technical personnel in this field to understand the technical content of this patent and implement it accordingly. According to the description, claims and drawings disclosed in this specification, technical personnel in this field can easily understand the relevant purposes and advantages of this patent.

[0051] In order to make the purpose, technical solutions and advantages of this patent clearer, the implementation method of this patent will be further described in detail below in conjunction with the accompanying drawings.

[0052] Example 1

[0053] like Figure 1 The anti-leakage pen tip shown includes a ball 1, a ball seat 2 and a spring 3. The ball 1 has a diameter of 0.5 mm, a surface roughness of Ra0.012 μm, and is made of tungsten carbide hard alloy; the ball seat 2 is a full needle tube shape, made of 304 stainless steel tube with a Vickers hardness of 340-380 HV. The total length of the pen tip (including the ball 1) is 6.50-6.60 mm, preferably 6.55 mm; the outer diameter of the ball seat 2 is 0.99-1.01 mm, preferably 1.00 mm; the front end of the ball seat 2 is processed with a pressure point tool 4 to form four centrally symmetrical pits 23, and the rear end of the pen tip is provided with a spring positioning point 25 for fixing the spring 3.

[0054] The overall internal structure of the pen tip is as follows Figure 2 , Figure 3As shown, the rear end of the ball seat body 2 is a small hole 26 with the same diameter, and the diameter is preferably designed to be 0.65±0.01mm. The front end of the ball seat body 2 is processed by a pressure point tool 4 to form four centrally symmetrical pits 23, which are protruding inside the tube and connected at the bottom to form a bowl seat 22 that supports the ball 1; the ball seat 2 body is secondary processed by a slot punching tool 5 to form an oil groove 21 and a small hole 26. The depth of the oil groove 21 is about half the depth of the bowl seat 22. The oil groove 21 is not directly connected to the inner hole 24, but is connected through the rear half of the small hole 26 as an ink channel. When writing, after the ink enters the pen head, it passes through the small hole 26, the inner hole 24, and the oil groove 21 in turn, and then flows out to the writing surface with the rolling of the ball 1, forming continuous writing.

[0055] The top view of the oil tank 21 is as follows Figure 4 As shown, from this angle, it can be seen that the pressure point processing uses four centrosymmetrical pressure point tools 4 to press down at the same time, and the force forms four centrosymmetrical pits 23 on the outside of the ball seat body 2, and the bottom of the pit 23 bulges inside the ball seat body 2 and is connected to form a bowl seat 22. The bowl seat 22 is processed by a slot punching tool 5 to form an oil groove 21 and a small hole 26, wherein the projection shape of the oil groove 21 is rectangular, and the projection shape of the small hole 26 is circular.

[0056] Spring 3 has the following appearance: Figure 5 As shown, the spring 3 is divided into four parts, namely, the ejector pin 31, the front parallel ring 32, the effective ring 33, and the rear parallel ring 34. The inner and outer diameters of the three parts, namely, the front parallel ring 32, the effective ring 33, and the rear parallel ring 34, are consistent, and their outer diameters are slightly smaller than the diameter of the inner hole 24 of the ball seat body 2, to ensure that the spring 3 is not easy to shake and will not get stuck. The spring 3 is preferably designed to be 0.63-0.64mm. The ejector pin 31 is a straight section, and the wire diameter is designed to be 0.1mm.

[0057] The shape of the pressure point tool 4 is as follows Figure 6 , 7 As shown, the pressing tool 4 is a pointed cone, the pressing blade body 42 is supported by a multi-section cylinder, the pressing blade head 41 is located at the top of the tool, and the part that contacts the pen tip is an elliptical cross-section. This shape of the pressing blade head 41 ensures that the bottom of the pit 23 formed after pressing can be connected to form a bowl seat 22.

[0058] The slot punching tool 5 has a complete shape as Figure 8 , 9 As shown, the slot punching tool 5 is a pointed cone as a whole, the slot punching tool body 53 is supported by a multi-section cylinder, and the tool head is divided into a small hole punching tool 51 and an oil groove punching tool 52; the surrounding part is the oil groove punching tool 52, the projected shape is a centrally symmetrical rectangle, and the oil groove 21 is formed by pressing down, and the width of the oil groove 21 is preferably 0.09mm; the central part is the small hole punching tool 51, the projected shape is a circle, and the small hole 26 is formed by pressing down, and the diameter of the small hole 26 is preferably 0.27mm.

[0059] The above anti-leakage needle pen tip and neutral ink A black matching test obtained the following results:

[0060] 1. Neutral ink A black, viscosity 1938 / 641mPa·s (6r / 60r), surface tension 39.4mN / m, pH value 8.83, ink particle size D50 0.132μm; test conditions: German HUTT writing instrument, writing angle 70°, writing speed 4.5m / min, writing pressure 1N, stitch spacing 1mm, writing interface is 70g writing paper specified in ISO14145;

[0061] 2. The test results of writing performance are as follows: the pen core with an ink filling volume of 1.05g has good initial writing performance, an average ink output of 108g / 100m, a line length of 950-1000m, a total wear of the pen head bowl 22 of 0.006mm, normal writing lines, no ink accumulation, broken lines or other abnormalities on the pen head and lines, and the writing performance meets the national standard requirements for gel pen cores; other application properties such as intermittent writing, ink dripping, high temperature storage, low temperature resistance, and drying resistance all meet the national, industry or enterprise standard requirements.

[0062] 3. We conducted a special experiment on the advantages of the anti-leakage needle-tube pen tip and compared it with the existing ordinary needle-tube spring pen tip. The comparison results are as follows:

[0063] Table 1 Comparison results of special test on anti-leakage needle pen tip (0.5mm) matching neutral ink A black

[0064]

[0065]

[0066] Among them, the test method for hanging ink dripping is: ensure that the pen core has normal initial writing. Within 10S after drawing a line, remove the cap and place the pen head vertically with the cap facing down in the hole of a special fixture for ink dripping test. After placing it under test conditions for 30 minutes (24 hours for spring head), observe the ink dripping situation of the pen head.

[0067] The test method for bottoming out ink leakage is as follows: ensure that the pen core has normal initial writing performance, assemble it into a finished pen (the weight of the finished pen is 13.0±0.5g), remove the cap and place the pen head with the cap facing downward in the hole of a special fixture for bottoming out ink leakage, ensure that the pen head contacts the bottom plate of the fixture vertically, place it under test conditions for the specified time, and observe the ink leakage.

[0068] From the comparative test of neutral ink A black, it can be seen that compared with the conventional neutral needle tube spring pen tip, the anti-leakage needle tube pen tip provided by the utility model has high material hardness, good wear resistance, good hand feel, lower proportion of hanging ink dripping and bottom leakage, and good anti-leakage ability.

[0069] Example 2

[0070] Select the same 0.5mm ball 1 diameter anti-leakage needle pen tip as in Example 1.

[0071] The above anti-leakage needle pen tip and neutral quick-drying ink B black matching test obtained the following results:

[0072] 1. Neutral ink B black, viscosity 1591 / 280mPa·s (6r / 60r), surface tension 35.7mN / m, pH value 8.45, ink particle size D50 0.070μm; test conditions: German HUTT writing instrument, writing angle 70°, writing speed 4.5m / min, writing pressure 1N, stitch spacing 1mm, writing interface is 70g writing paper specified in ISO14145;

[0073] 2. The test results of writing performance are as follows: the pen core with an ink filling volume of 1.05g has good initial writing performance, an average ink output of 98g / 100m, a line length of 1000-1200m, a total wear of the pen head bowl 22 of 0.012mm, normal writing lines, no ink accumulation, broken lines or other abnormalities on the pen head and lines, and the writing performance meets the national standard requirements for gel pen cores; other application properties such as intermittent writing, ink dripping, high temperature storage, low temperature resistance, drying resistance, drying time, etc. all meet the national, industry or enterprise standard requirements.

[0074] 3. We conducted a special experiment on the advantages of the anti-leakage needle-tube pen tip and compared it with the existing ordinary needle-tube spring pen tip. The comparison results are as follows:

[0075] Table 2 Comparison results of special test on anti-leakage needle pen tip (0.5mm) matching neutral quick-drying ink B black

[0076]

[0077] The test methods for hanging ink dripping and bottom ink leakage are the same as those in Example 1.

[0078] From the comparative test of neutral quick-drying ink B black, it can be seen that compared with the conventional neutral needle tube spring pen tip, the anti-leakage needle tube pen tip provided by the utility model has high material hardness, good wear resistance, good hand feel, significantly lower proportion of hanging ink dripping and bottom leakage, and good anti-leakage ability.

[0079] Example 3

[0080] A 0.4mm ball 1 diameter anti-leakage needle pen tip is selected, and some pen tip parameters and processing techniques are adjusted: the ball 1 diameter is 0.4mm, the outer diameter of the ball seat body 2 is 0.79-0.81mm, preferably 0.80mm; the rear end of the ball seat body 2 is a small hole 26 with the same diameter, and the diameter is preferably designed to be 0.52±0.01mm. The diameter of the spring 3 is preferably designed to be 0.50-0.51mm. The central part of the slot punching tool 5 is a small hole punching tool 51, the projected shape is circular, and its diameter is preferably 0.23mm, and the small hole 26 is formed by pressing down; the surrounding part is an oil groove punching tool 52, and the projected shape is a centrally symmetrical rectangle, which is pressed down to form an oil groove 21, and the width of the oil groove 21 is preferably 0.08mm. The remaining dimensions and processes are the same as those of the 0.5mm ball 1 diameter anti-leakage needle pen tip in Example 1.

[0081] The above anti-leakage needle pen tip and neutral quick-drying ink C blue matching test obtained the following results:

[0082] 1. Neutral quick-drying ink C blue, viscosity 1096 / 581mPa·s (6r / 60r), surface tension 30.9mN / m, pH value 8.46, ink particle size D50 0.186μm; test conditions: German HUTT writing instrument, writing angle 70°, writing speed 4.5m / min, writing pressure 1N, stitch spacing 1mm, writing interface is 70g writing paper specified in ISO14145;

[0083] 2. The test results of writing performance are as follows: the pen core with an ink filling volume of 1.05g has good initial writing performance, an average ink output of 83g / 100m, a line length of 1150-1400m, a total wear of the pen head bowl 22 of 0.016mm, normal writing lines, no abnormalities such as ink accumulation and line breakage on the pen head and lines, and the writing performance meets the national standard requirements for gel pen cores; other application properties such as intermittent writing, ink dripping, high temperature storage, low temperature resistance, drying resistance, drying time, etc. all meet the national, industry or enterprise standard requirements.

[0084] 3. We conducted a special experiment on the advantages of the anti-leakage needle-tube pen tip and compared it with the existing ordinary needle-tube spring pen tip. The comparison results are as follows:

[0085] Table 3 Comparison results of special test on anti-leakage needle pen tip (0.4mm) matching neutral quick-drying ink C blue

[0086]

[0087] The test methods for hanging ink dripping and bottom ink leakage are the same as those in Example 1.

[0088] From the comparative test of neutral quick-drying ink C blue, it can be seen that compared with the conventional neutral needle tube spring pen tip, the anti-leakage needle tube pen tip provided by the utility model has high material hardness, good wear resistance, good hand feel, significantly lower proportion of hanging ink dripping and bottom leakage, and good anti-leakage ability.

[0089] Example 4

[0090] Select the same 0.4mm ball 1 diameter anti-leakage needle pen tip as in Example 3.

[0091] The above anti-leakage needle pen tip was tested with neutral quick-drying ink D black, and the following results were obtained:

[0092] 1. Neutral quick-drying ink D black, viscosity 416 / 239mPa·s (6r / 60r), surface tension 32.2mN / m, pH value 8.07, ink particle size D50 0.165μm; test conditions: German HUTT writing instrument, writing angle 70°, writing speed 4.5m / min, writing pressure 1N, stitch spacing 1mm, writing interface is 70g writing paper specified in ISO14145;

[0093] 2. The test results of writing performance are as follows: the pen core with an ink filling volume of 1.05g has good initial writing performance, an average ink output of 98g / 100m, a line length of 1000-1150m, a total wear of the pen head bowl 22 of 0.006mm, normal writing lines, no ink accumulation, broken lines or other abnormalities in the pen head and lines, and the writing performance meets the national standard requirements for gel pen cores; other application properties such as intermittent writing, ink dripping, high temperature storage, low temperature resistance, drying resistance, drying time, etc. all meet the national, industry or enterprise standard requirements.

[0094] 3. We conducted a special experiment on the advantages of the anti-leakage needle-tube pen tip and compared it with the existing ordinary needle-tube spring pen tip. The comparison results are as follows:

[0095] Table 4. Comparison results of special test on anti-leakage needle pen tip (0.4mm) matching neutral quick-drying ink D black

[0096]

[0097] The test methods for hanging ink dripping and bottom ink leakage are the same as those in implementation 1.

[0098] From the comparative test of neutral quick-drying ink D black, it can be seen that compared with the conventional neutral needle tube spring pen tip, the anti-leakage needle tube pen tip provided by the utility model has high material hardness, good wear resistance, good hand feel, significantly lower proportion of hanging ink dripping and bottom leakage, and good anti-leakage ability.

[0099] Example 5

[0100] A 0.7mm ball 1 diameter anti-leakage needle pen tip is selected, and some pen tip parameters and processing techniques are adjusted: the ball 1 diameter is 0.7mm, the outer diameter of the ball seat body 2 is 0.99-1.01mm, preferably 1.00mm; the rear end of the ball seat body 2 is a small hole 26 with the same diameter, and the diameter is preferably designed to be 0.65±0.01mm. The diameter of the spring 3 is preferably designed to be 0.62-0.64mm. The central part of the slot punching tool 5 is a small hole punching tool 51, the projected shape is circular, and its diameter is preferably 0.40mm, and the small hole 26 is formed by pressing down; the surrounding part is an oil groove punching tool 52, and the projected shape is a centrally symmetrical rectangle, which is pressed down to form an oil groove 21, and the width of the oil groove 21 is preferably 0.10mm. The remaining dimensions and processes are the same as those of the 0.5mm ball 1 diameter anti-leakage needle pen tip in Example 1.

[0101] The above anti-leakage needle pen tip and neutral quick-drying ink E red were matched to obtain the following results:

[0102] 1. Neutral quick-drying ink E red, viscosity 3357 / 642mPa·s (6r / 60r), surface tension 26.4mN / m, pH value 7.71, ink particle size D50 0.305μm; test conditions: German HUTT writing instrument, writing angle 70°, writing speed 4.5m / min, writing pressure 1N, stitch spacing 2mm, writing interface is 70g writing paper specified in ISO14145;

[0103] 2. The test results of writing performance are as follows: the pen core with an ink filling volume of 1.05g has good initial writing performance, an average ink output of 128g / 100m, a line length of 750-900m, a total wear of the pen head bowl 22 of 0.003mm, normal writing lines, no abnormalities such as ink accumulation and line breakage on the pen head and lines, and the writing performance meets the national standard requirements for gel pen cores; other application properties such as intermittent writing, ink dripping, high temperature storage, low temperature resistance, drying resistance, drying time, etc. all meet the national, industry or enterprise standard requirements.

[0104] 3. We conducted a special experiment on the advantages of the anti-leakage needle-tube pen tip and compared it with the existing ordinary needle-tube spring pen tip. The comparison results are as follows:

[0105] Table 5 Comparison results of the special test of anti-leakage needle pen tip (0.7mm) matching neutral quick-drying ink E red

[0106]

[0107] The test methods for hanging ink dripping and bottom ink leakage are the same as those in Example 1.

[0108] From the comparative test of neutral quick-drying ink E red, it can be seen that compared with the conventional neutral needle tube spring pen tip, the anti-leakage needle tube pen tip provided by the utility model has high material hardness, good wear resistance, good hand feel, significantly lower proportion of hanging ink dripping and bottom leakage, and good anti-leakage ability.

[0109] In the specification of the present invention, terms indicating directions, such as "front", "rear", "up", "down", "left", "right", "side", "top", "bottom", etc., are used to describe various exemplary structural parts and components of the present invention, but these terms are used here only for the convenience of description and are determined based on the example orientations shown in the drawings. Since the embodiments disclosed in the present invention can be set in different directions, these terms indicating directions are only used as illustrations and should not be regarded as limitations. For example, "up" and "down" are not necessarily limited to directions opposite to or consistent with the direction of gravity.

[0110] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present utility model will not further describe various possible combinations.

[0111] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A leak-proof pen tip, comprising a ball (1), a ball seat (2) and a spring (3), wherein the ball seat (2) is a hollow tube and has a bowl seat (22) for supporting the ball (1), the bowl seat (22) has an inner hole (24) at its center, the ball (1) is embedded in the bowl seat (22) and the inner hole (24), the spring (3) is inside the ball seat (2), and the spring (3) has a thimble (31), characterized in that: The ejector pin (31) is pushed onto the ball (1) through the inner hole (24); the bowl seat (22) is processed into an oil groove (21) by a slot punching tool (5); the oil groove (21) is distributed at the front end of the bowl seat (22) and is in contact with the ball (1); the oil groove (21) is not directly connected to the inner hole (24); and the oil groove (21) is not connected to the pit (23).

2. The writing head according to claim 1, characterized in that: The bowl seat (22) is formed at the front end of the ball seat body (2) by processing the recess (23) with a pressure point tool (4), and the recess (23) protrudes from the inside of the ball seat body (2) to form the bowl seat (22).

3. The writing head according to claim 2, characterized in that: The number of the pits (23) is in the range of 2-8, and the shapes include one or more combinations of circular, elliptical, triangular, square or pentagonal.

4. The writing tip according to claim 3, characterized in that: The number of the oil grooves (21) is in the range of 2-8, and the shapes include one or more combinations of circular, elliptical, triangular, square or pentagonal.

5. The writing head according to claim 1, characterized in that: The end of the ball seat body (2) has a small hole (26); The spring (3) further comprises a front parallel coil (32), an effective coil (33) and a rear parallel coil (34); the front parallel coil (32) is located at the front end of the spring (3) and connects the ejector pin (31) and the effective coil (33); the rear parallel coil (34) is located at the end of the spring (3) and contacts the small hole (26); the inner and outer diameters of the front parallel coil (32), the effective coil (33) and the rear parallel coil (34) are the same, so that the ink flow rate remains uniform.

6. The writing head according to claim 5, characterized in that: The ball seat body (2) comprises a spring positioning point (25), and the spring positioning point (25) is used to fix the spring (3). The spring positioning point (25) is located at the connection between the small hole (26) and the rear parallel ring (34) and is formed by the slot punching tool (5).

7. The writing tip according to claim 1, characterized in that: The diameter of the ball (1) is in the range of 0.3-0.8 mm; The ball (1) is a hard alloy ball or a ceramic ball.

8. The writing head according to claim 1, characterized in that: The material of the ball seat body (2) is a stainless steel pipe, the outer diameter of the stainless steel pipe is in the range of 0.7-1.2 mm, and the stainless steel is one of 304, 304L, 316 or 316L.

9. A leak-proof needle tube pen core, comprising a pen core tube body, ink and a leak-proof pen tip according to any one of claims 5 or 6, characterized in that: The anti-leakage pen tip is located at the front end of the pen core tube body, and the pen core tube body has a tubular cavity connected to the small hole (26), and the tubular cavity is used to contain the ink; The ink is one of neutral ink, water-based ink or emulsified ink.

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