JPH0376676B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method and apparatus for forming grooves for generating dynamic pressure on a shaft, and particularly relates to a method and an apparatus for forming grooves for generating dynamic pressure on the shaft of a hydrodynamic type fluid bearing. In the method and apparatus for printing a figure whose part is a non-printing part and etching the non-printing part to form a groove for generating dynamic pressure, This improves printing accuracy and forms accurate grooves for generating dynamic pressure.

[Conventional technology]

Conventionally, grooves for generating dynamic pressure on the shaft of hydrodynamic bearings have been formed by etching, but as a pre-process to this etching process, grooves for generating dynamic pressure are formed on the outer circumferential surface of the shaft. It is necessary to perform printing using a printing plate in which the groove portion is a non-printing portion and the other portion is a printing portion. For this printing process, for example, a method using a screen printing plate shown in FIGS. 20 and 21 is known. This screen printing method uses a mesh-like screen 1 whose length is the same as the circumferential length L ₁ for one rotation of the shaft.
A printing plate 3 in which herringbone-shaped grooves 2 are embedded in parallel as a non-printing area is used, and the printing area of the screen 1 is filled with corrosion-resistant ink 4 applied to the top surface of the printing plate 3. While moving the printing plate 3 in the direction of the arrow shown in the figure, the shaft 5 that is in contact with the lower surface of the printing plate 3 is rotated once, and as the printing plate 3 moves, the corrosion resistance of the upper surface of the printing plate 3 changes. The ink 4 is pushed out to the outer diameter surface of the shaft 5 through the image area of the screen 1 by a blade-shaped squeegee 6 brought into contact with the screen 1 directly above the shaft 5.

[Problem that the invention seeks to solve]

In general, the grooves for generating dynamic pressure on a shaft are inclined with respect to the axis, and adjacent grooves for generating dynamic pressure are arranged in parallel at narrow intervals. The original shape of the pressure generating groove is divided into two parts at some point. Therefore, as shown in FIG. 21, the printing plate 3 used in the screen printing method has a groove pattern 2a on the printing start end side and a groove pattern 2b on the printing end side with respect to the moving direction of the printing plate 3. The original groove shape is divided by orthogonal straight lines.

Therefore, when printing with the above-mentioned printing plate 3, the ink printed on the shaft 5 at the start of printing is not sufficiently dried, and the image area at the end of printing is wet. Since the ink is printed, when the shaft 5 rotates once, the ink from the printing start end side and the printing end side mixes and oozes out onto the joining generatrix of the shaft 5. As a result, the printing start end side and the printing end side The non-printing portions 7a, 7b formed on the shaft 5 when the non-printing portions of the groove molds 2a, 2b are joined to the sides are provided with a second
As shown in FIG. 2, a protruding portion 8a protruding from the printed portion 8 printed by the image portion is printed along the joining generatrix. For this reason, the above axis 5
Even if the non-printed portion 7 of the above is corroded, the protrusion 8a on the joining busbar is not corroded, so as shown in FIG. A recessed portion 9a is formed, and when used as a dynamic pressure type flow pair bearing, a predetermined fluid film forming function is impaired, and this becomes a factor that significantly deteriorates bearing performance.

In order to solve the problem of printing defects in the printing area on the connecting generatrix of the shaft due to the printing line area of the print start side and print end side, the groove shape of the print start side and print end side should be divided into shapes. It is necessary to use a printing plate that does not have a printing plate, but in this case, the shaft must be rotated more than one revolution to join the image area on the print start side and the image area on the print end side. The printing part printed on the shaft at the start of printing is
When the printing plate is contacted again at the end of printing, the insufficiently dried ink on the printing start side spreads to the surrounding area.
It will protrude into the non-printing area of the area that has been contacted again.

In addition to the above, with screen printing printing plates, corrosion-resistant ink often flows down from the mesh at the end of the screen at the end of printing, which stains the non-printing part of the shaft and further promotes printing defects. This has led to the result of

As mentioned above, graphics printed by screen printing have problems with printing accuracy and require correction work to the printed graphics after printing is completed, making it difficult to print in large quantities.

In view of the above-mentioned problems, it is an object of the present invention to provide a method and apparatus capable of forming accurate dynamic pressure generating grooves by eliminating printing defects in the overlapping portion of the printing start end side and the printing end side of the shaft. purpose.

[Means for solving problems]

The invention of a method for forming grooves for generating dynamic pressure on a rotating shaft uses a printing original roll and an offset roll that rotates in contact with the printing original roll, and the shaft is rotated once while in contact with the offset roll. A non-image area in the shape of a groove for generating dynamic pressure and a circle in the shape of a groove for generating dynamic pressure are provided on the outer peripheral surface of the printing original roll, and between the printing start end side and the printing end side, the non-printing part is in the shape of a groove for generating dynamic pressure. A contour figure in the circumferential direction is arranged in an alternately connected manner in the circumferential direction, and a contour figure in the circumferential direction has a groove shape for generating dynamic pressure provided in the image line part on the printing start end side. , and the contour figure in the circumferential direction of the shape of the groove for generating dynamic pressure provided in the print area on the print end side, are both provided in the print area in the center between the print start side and the print end side. Corrosion-resistant ink is applied to a printing original plate, which has an undivided shape that is approximately equal to the circumferential contour of the groove for generating dynamic pressure, and transferred to an offset roll, and the transferred corrosion-resistant ink is applied to the outer periphery of the shaft. After printing on the surface, the non-printed part of the shaft is corroded to form grooves for generating dynamic pressure.

Furthermore, the invention of the device for forming grooves for generating dynamic pressure on the shaft is an invention relating to the offset roll and printing plate roll used directly in the printing process, which is the main part of the invention of the above-mentioned forming method. On the outer peripheral surface of the printing original roll that rotates in contact with the roll, there is a printing original whose length from the printing start edge to the printing end exceeds the circumferential length corresponding to one revolution of the shaft by an appropriate amount. This printing original plate has a non-image area in the shape of a groove for generating dynamic pressure, and an image area having a circumferential outline figure in the shape of a groove for generating dynamic pressure in the circumferential direction. connected and arranged alternately,
A circumferential contour figure of the shape of a groove for generating dynamic pressure provided in the printing area on the printing start end side, and a circumferential outline of the shape of the groove for dynamic pressure generation provided in the printing area on the printing end side. The figure is an undivided shape that is approximately equal to the circumferential outline figure of the groove for generating dynamic pressure provided in the central drawing area between the printing start end side and the print end side. It is.

[Effect]

In the method of the present invention, the corrosion-resistant ink attached to the printing original plate of the printing original plate roll is once transferred to the offset roll, and the corrosion-resistant ink transferred to the offset roll is printed on the shaft.
The ink has dried to some extent on the offset roll, and even if the shaft rotates more than one revolution and the printing part on the printing start side contacts the offset roll again, the ink in the printing part that made contact again will not print. It does not spread to other areas. Therefore, the contour figure on the printing start end side of the groove for generating dynamic pressure is not stained at the end of printing.

In addition, the printing original plate of the printing original plate roll used in this invention has a printing length from the printing start end to the printing end that is longer than the circumferential length for one rotation of the shaft, and a printing original plate provided in the printing area on the printing start end side. The circumferential contour of the groove shape for dynamic pressure generation and the circumferential contour figure of the groove shape for dynamic pressure generation provided in the print area on the print end side are both the same as the print start edge side. Since it has an undivided shape that is almost the same as the circumferential contour of the groove for generating dynamic pressure provided in the drawing area in the center between the end and the end side, the shaft can be rotated more than one rotation. By printing, the circumferential contour figure of the shape of the groove for generating dynamic pressure on the print start side and the circumferential contour figure of the shape of the groove for dynamic pressure generation on the print end side are joined and printed. Things will go away.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a side view showing a printing apparatus used in the method of the present invention. In the figure, the outer peripheral surface of a printing original roll 10 is an intaglio printing original 20, and an offset roll 11 made of a rubber-like elastic body is rotatably installed in contact with this printing original roll 10. . The above printing original roll 10
A pick-up roll 12 is disposed so as to be rotatable in contact with it. When the pick-up roll 12 contacts the printing original roll 10 and rotates in the opposite direction,
The corrosion-resistant ink 14 adhering to the outer peripheral surface of the pick-up roll 12 in the ink tank 13 is applied to the printing original plate 20 of the printing original plate roll 10, and the printing original plate 20
The corrosion-resistant ink on the plate surface (non-image area) 21 is stripped off by the doctor blade 15, and the corrosion-resistant ink on the concave surface (image area) 22 is removed from the printing plate roll 1.
The corrosion resistant ink 20a transferred to the offset roll 11 is transferred to the offset roll 11 which is in contact with the ink and rotates in the opposite direction.
Printing is performed on a shaft 30 rotatably disposed in contact with the shaft 1.

FIGS. 2 and 3 are a developed view and a cross-sectional view taken along the line 2, respectively, showing a first embodiment of the printing original plate 20 of the printing original plate roll 10 described above. Original printing plate 2
0, a non-printing part 21 in the shape of a herringbone-like groove for generating dynamic pressure and a concave printing part 22 having an outline figure in the shape of a groove for generating dynamic pressure are connected in the circumferential direction. They are arranged alternately. The non-printing portion 21 in the shape of a groove for generating dynamic pressure is connected to a concave drawing portion 22 having an outline figure in the shape of a groove for generating dynamic pressure on both sides in the circumferential direction and on both sides in the axial direction. There is.

The number of non-image areas 21 arranged in the shape of the grooves for generating dynamic pressure is the same as the required number of grooves for generating dynamic pressure formed on the shaft, and is located on the right side in the circumferential direction (printing start end side).
What is the outline figure of the shape of the groove for dynamic pressure generation provided in the printing area 22a and the outline figure of the shape of the groove for dynamic pressure generation provided in the printing area 22b on the left side (printing end side) in the circumferential direction? , in both cases, the contour figure of the groove for dynamic pressure generation is not divided in the generatrix direction, but a circle in the shape of the groove for dynamic pressure generation is provided in the central drawing area between the printing start end side and the printing end side. It has an undivided shape that is approximately equal to the contour figure in the circumferential direction. Further, the width dimension (circumferential direction length) of the right side drawing section 22a in the circumferential direction is approximately 1/2 of the width dimension of the drawing section 22 between adjacent non-printing sections 21. The width dimension (circumferential direction length) of the left drawing part 22b in the circumferential direction is the same as that of the adjacent non-printing part 2.
The length is approximately 1/2 of the width dimension of the printing area 22 between 1 and 1 plus the overlap printing length l of the printing area 24 of overlap printing, and Drawing area 2
It is shorter than the width dimension of 2. The outline figures at both circumferential ends of the image line portions 22a and 22b at both ends in the circumferential direction are parallel to the outline figure on the circumferential side of the shape of the groove for generating dynamic pressure. It extends an appropriate length outward in the axial direction from the non-printing portion 21 having the shape of . The portion outside the non-printing area 21 in the shape of the dynamic pressure generating groove in the axial direction is still a band-shaped printing area 23 extending in the circumferential direction.

When the non-image area 21 and the image area 22 are arranged as described above, between point A of the image area 22a on the right side in the circumferential direction and point C of the image area 22b on the left side in the circumferential direction,
Or the upper or lower drawing area 23 in the axial direction
The length L ₁ between points B and D of is the length of the circumference corresponding to one rotation of the axis, but the printing length L from the printing start edge to the printing end is the above L ₁ , The length is the sum of the circumferential length _L2 between points C and D or between points A and B and the overlap printing length l.

In this way, the drawing portions 22 on both ends in the circumferential direction
Overlapping printing length l on at least one of a and 22b
By providing the overlapping print area 24 of
2b can be accurately matched with each other at the end of printing.

When using the printing original plate 20 described above and printing with the right side in the circumferential direction as the printing starting edge side, the corrosion-resistant ink 20a transferred from the printing original plate 20 to the offset roll 11 is applied to the shaft so that the starting edge side of the printing original plate 20 is printed. Printing starts from point A, and overlap printing area 2
Printing will end at the contour figure on the left side of 4, but the print length L ₁ from point A to point C will be printed while the axis rotates once, and from point C to point D. An image of printing length L ₂ up to is printed during more than one revolution of the axis. Drawing part 22,
The printing line portion 22a on the printing start end side of 23 and the printing line portion 24 of overlap printing on the printing end side are printed so as to overlap on the axis, and printing is completed.

FIG. 4 shows the printed shaft 30, and the printing portions 22 and 23 of the original printing plate 20 are the printing portions 32 and 23, respectively.
33, and the non-printing area 21 is the non-printing area 3.
1. In the figure, a non-printing area indicated by reference numeral 31a corresponds to a non-printing area 21a on the printing start end side of the printing original plate 20, and a non-printing area 31b next to this non-printing area 31a is on the printing end side of the printing original plate 20. Assuming that it corresponds to the non-image area 21b, the image area 2 has a contour figure in the circumferential direction in the shape of a groove for generating dynamic pressure.
2a and 22b are arranged in an undivided shape, so that no joining portion occurs in the corresponding non-printing portions 31a and 31b.

Further, when the shaft 30 rotates more than one rotation,
The printed part printed by the printing length L ₂ from the printing starting edge point A to the printing point B of the printing original plate 20 comes into contact with the offset roll again. Since it is printed with corrosion-resistant ink that has been transferred to and dried to a certain extent, it does not adhere to the offset roll again and spread, and the non-printed area of the printing length L ₂ on the printing start side is smudged. Never.

The printing section 32 of the shaft 30 where the above printing was performed,
After applying tape to the non-printed parts located on both sides of the axial direction from 33, when the non-printed parts 31 are immersed in a corrosive liquid to corrode, grooves 40 for generating dynamic pressure are formed as shown in FIG. be done. After that, the tape attached to the shaft 30 is peeled off and the shaft 30 is immersed in a stripping solution to dissolve and remove the corrosion-resistant ink on the printed parts 32 and 33, thereby removing the joints of the contour figures in the form of grooves for generating dynamic pressure. There are no recesses, etc.
A shaft with accurate herringbone-shaped grooves for generating dynamic pressure can be obtained.

6 and 7 show a second embodiment of the printing original plate, which is a modification of the printing original plate of the first embodiment. In this embodiment, the width dimension in the circumferential direction of the image areas 22a and 22b at the print start end side and the print end side of the printing original plate 20 is the circumferential width of the image area 22 between the adjacent non-image areas 21. It is the same as the width dimension in the direction. Also,
The contour figures at both ends in the circumferential direction of the drawing portions 22a and 22b on both ends in the circumferential direction are circumferential contour figures in the shape of grooves for generating dynamic pressure. The contour figure on the right end side of the drawing part 22a on the right end side in the circumferential direction is a groove for generating dynamic pressure by an appropriate length outward in the axial direction from the non-printing part 21 in the shape of the groove for generating dynamic pressure. Extends parallel to the circumferential contour of the shape.

The image area 23 located outside the non-image area 21 in the axial direction in the shape of a groove for generating dynamic pressure has a contour figure on the left end side in the circumferential direction that is similar to the image area 2 on the left end side in the circumferential direction.
2b to the left of the circumferential contour figure of the groove shape for dynamic pressure generation on the left end side by a length equal to the circumferential width dimension of one non-printing part 21 plus the overlap printing length l. It is shifted in the direction. In this embodiment, the non-printing area 2
The number of ``1'' arrays is one less than in the first embodiment.

Printing length L in printing original plate 20 of this modification
is the circumferential length L from point A to point C (or point B to point D), which corresponds to one revolution of the shaft, and the circumferential length L from _point C (or point A to point B). ₂ plus the overlap printing length l.

According to the printing original plate 20 described above, when the shaft rotates more than one rotation, the right end side and the left end side of the upper and lower image portions 23 in the axial direction are joined on the rotation shaft. A contour figure 21c shown by a two-dot chain line in FIG. 6 is located between the printing start end side printing area 22a and the printing end side printing area 22b having a circumferential contour pattern in the shape of a groove for generating dynamic pressure. is formed as a non-printing portion on the terminal side.

In this way, a printed portion having the same figure as that shown in FIG. 4 is printed on the shaft.

Figures 8 and 9 show a third embodiment of the original printing plate, in which annular grooves are provided at both ends in the axial direction of a herringbone-shaped groove for generating dynamic pressure to form a lubricant reservoir. This figure shows the arrangement of drawing areas and non-printing areas.

The printing original plate 20 of this embodiment has an upper non-printing area 25 having an appropriate width in the generatrix direction at the upper and lower edges in the axial direction of the non-printing area 21 of the printing original plate shown in FIG. The non-image portions 26 on the lower end side are arranged in the circumferential direction, and the image portions 22 having contour figures in the shape of grooves for generating dynamic pressure are arranged. In addition, the upper and lower drawing portions 23 in the axial direction
The edges of the right end side and the left end side are parallel to the generatrix direction.

Of the printing length L of the printing original plate 20 of this embodiment, the circumference length from point A to point C is equivalent to one rotation of the shaft.
The length corresponding to _L1 , which is the length _L2 from point C to point D plus the overlap printing length l, is the length to be printed over one rotation. Note that the printing length can be shortened by moving the upper and lower print portions 23 in the axial direction of FIG. 8 to the right by a length of _L2 .

FIG. 10 shows the shaft 30 printed by the above printing original plate 20, and the upper and lower image portions 23 in the axial direction of the image portion 22 having contour figures in the shape of grooves for generating dynamic pressure. and printing parts 32 and 33, respectively.
The non-printing area 21 between adjacent printing areas 22 becomes the non-printing area 31, and the non-printing area 25, 26 on the upper end side and the lower end side become the non-printing area 35, 36.
becomes. Non-printed parts 31, 35, on the outer diameter surface of the shaft 30,
The entire surface of the portion located axially outward from 36 becomes the printing section 33.

When the above shaft is etched, as shown in FIG. 11, a groove 40 for generating dynamic pressure is formed by the non-printed part 31, and a lubricant reservoir part 41, by the non-printed part 35, 36. 42 is molded.

According to the printing original plate 20 described above, when the shaft 30 rotates more than one rotation and the right end side and the left end side of the upper and lower image portions 23 in the axial direction are joined on the shaft, there is a discrepancy in the joint part. The upper end of the non-printing portion 35 on the upper end side of the shaft 30 and the non-printing portion 36 on the lower end side of the shaft 30
Even if there is a step at the lower end of the non-printing area 35, 3
6 are portions that serve as lubricant reservoirs 41 and 42, and therefore do not impede the dynamic pressure generation function.

FIG. 12 and FIG. 13 show a fourth embodiment of the printing original plate, in which both ends of the herringbone-shaped groove for generating dynamic pressure in the axial direction are extended outward in the axial direction from the lubricant reservoir. This figure shows the arrangement of the image area and the non-image area when forming the sealing groove.

The printing original plate 20 of this embodiment has a non-printing area on the upper end side having an appropriate width in the generatrix direction inside the upper and lower edges of the non-printing area 21 of the printing original plate shown in FIG. 6 in the axial direction. 25 and a lower end non-image portion 26 are arranged in the circumferential direction, and protruding non-image portions 27 and 28 are provided at the upper and lower end portions of the non-image portion 21, respectively.
The structure consists of an array of .

Printing length L of printing original plate 20 in this example
As in the embodiment shown in _FIG .
The length is the sum of the circumferential length _L2 and the overlap printing length l.

FIG. 14 shows the shaft 30 printed by the above printing original plate 20, in which a non-printing area 21 in the shape of a groove for generating dynamic pressure and non-printing areas 27 and 28 in the protrusion are respectively non-printing. Printed portions 31: 37, 38, and non-printing portions 25, 26 on the upper end side and lower end side become non-printed portions 35, 36. In addition, the printing part 22 connected to the non-printing part 21 on both sides in the circumferential direction serves as a printing part 32, and the printing part 23 on the upper and lower sides in the axial direction
is printed as the printing section 33.

After applying tape to the unprinted parts located on both sides of the printing parts 32 and 33 in the axial direction of the shaft 30, etching is performed on the shaft 30.
As shown in Figure 5, the non-printing section 31 and the non-printing section 3
5 and 36 respectively form grooves 40 for generating dynamic pressure.
and lubricant reservoir portions 41, 42 are formed, and sealing grooves 43, 4 are formed by non-printed portions 37, 38.
4 is molded.

FIG. 16 and FIG. 17 show a fifth embodiment of the printing original plate, and show a case in which printing line portions 22 having contour figures in the shape of herringbone-shaped grooves for generating dynamic pressure are arranged. Drawing portions 22a, 2 on both ends
2b has an undivided contour figure in the shape of a groove for generating dynamic pressure, and the plate surface other than the image area 22 is a non-image area 21.

The printing starting edge of the printing original plate 20 of this embodiment is point A, and the printing ending point is point D. The printing length L from the printing start point A to the printing end point D is _the circumferential length L for one rotation of the axis from point A to point C.
The length is the sum of the circumferential length L ₂ to the point.

FIG. 18 shows the shaft 30 printed by the printing original plate 20 described above, in which an image area 22 having an outline figure in the shape of a groove for generating dynamic pressure is printed as a printing area 32, and a non-image area 21 is printed. is the non-print portion 31.

When the above-mentioned shaft is etched, the printed parts 32 stand out as shown in FIG. 19, and the non-printed parts 31 between the adjacent printed parts 32 become grooves 4 for generating dynamic pressure.
Formed into 0.

The printing original plates of each of the above embodiments have been described in the case where the image area is an intaglio plate, but on the contrary, the image area may be a letterpress plate, or other types of plates may be used. can.

Further, the shape of the groove for generating dynamic pressure formed according to the present invention is not limited to the herringbone shape of the embodiment, but may be a spiral shape or any other arbitrary shape.

Furthermore, the shaft 30 can be used not only as a rotating shaft but also as a fixed shaft of a hydrodynamic bearing.

Furthermore, although the outer peripheral surface of the printing original roll itself may be used as the printing original, the printing original plate may be attached to the outer peripheral surface of the printing original roll.

〔Effect of the invention〕

As described above, according to the present invention, the circumferential contour figure of the shape of the groove for generating dynamic pressure on the printing start end side and the circumferential contour figure of the shape of the groove for generating dynamic pressure on the printing end side This is because there is no part where the contour figures in the circumferential direction join each other after printing is completed, and moreover, it is possible to print with high precision without staining the contour figures with the corrosion-resistant ink on the printing start side. The grooves for generating dynamic pressure formed by processing have an accurate shape with no uneven parts on the side surfaces, and a shaft with a stable dynamic pressure generating function can be obtained.

Further, according to the present invention, since no defective printing portions occur in the printed graphics of the shaft, there is no need for correction work after printing is completed, making it easy to print in large quantities and, in turn, to mass produce shafts for hydrodynamic bearings.

[Brief explanation of drawings]

FIG. 1 is a side view showing a printing device used in the method of the present invention, FIG. 2 is a developed view showing a first embodiment of the printing original plate used in the invention, and FIG.
4 is a front view of the shaft printed by the printing original plate of the first embodiment, FIG. 5 is a front view of the shaft equipped with the groove for generating dynamic pressure according to the first embodiment, FIG. 6 is a developed view showing a second embodiment, which is a modification of the printing original plate of the first embodiment, FIG. 7 is a sectional view taken along the line -- in FIG. 6, and FIG. A developed view showing the third embodiment, FIG. 9 is a sectional view taken along the - line in FIG. 8, FIG. 10 is a front view of the shaft printed by the printing original plate of the third embodiment, and FIG. FIG. 12 is a developed view showing a fourth embodiment of the printing original plate used in the present invention, FIG. 13 is a sectional view taken along the - line in FIG. 12, and FIG. The figure is a front view of a shaft printed with the printing original plate of the fourth embodiment, and FIG. 15 is a front view of a shaft equipped with a groove for generating dynamic pressure according to the fourth embodiment.
FIG. 16 is a developed view showing the fifth embodiment of the printing original plate used in the present invention, and FIG. 17 is the − of FIG. 16.
18 is a front view of the shaft printed by the printing original plate of the fifth embodiment; FIG. 19 is a front view of the shaft equipped with grooves for generating dynamic pressure according to the fifth embodiment; FIG.
Figure 0 is a sectional view showing a printing plate used in the conventional screen printing method, Figure 21 is a plan view of the conventional screen printing plate, Figure 22 is a front view of the shaft printed by the conventional screen printing plate, and Figure 22 is a front view of the shaft printed by the conventional screen printing plate. FIG. 23 is a front view of a shaft provided with grooves for generating dynamic pressure using a conventional screen printing plate. In the figure, 10 is a printing original roll, 11 is an offset roll, 20 is a printing original plate, 20a is the corrosion-resistant ink transferred to the offset roll, 21 and 22 are a non-image area and an image area of the printing original plate, respectively, and 21a ，
21b is a non-printing area on the printing start end side and the printing end side;
22a and 22b are the image areas of the printing start end side and the printing end side, 30 is the shaft, 31 and 32 are the non-printing part and printing part of the shaft, respectively, 40 is the groove for generating dynamic pressure, and L is the printing length of the printing original plate. It is.

Claims (1)

[Scope of Claims] 1. A shaft is brought into contact with an offset roll that rotates in contact with a printing original plate roll, and the shaft is rotated more than one rotation, and is provided on the outer peripheral surface of the printing original plate roll, and a printing start end A non-printing area in the shape of a groove for generating dynamic pressure and a printing area having a circumferential outline figure in the shape of a groove for generating dynamic pressure are arranged alternately in the circumferential direction between the side and the printing end side. The circumferential contour figure of the groove for generating dynamic pressure that is connected and arranged and provided in the printing area on the printing start end side, and the shape of the groove for dynamic pressure generation provided in the printing area on the printing end side. The contour figure in the circumferential direction is almost equal to the contour figure in the circumferential direction of the groove for generating dynamic pressure provided in the central image area between the printing start end side and the printing end side. Corrosion-resistant ink is applied to the undivided printing plate and transferred to an offset roll. After the corrosion-resistant ink transferred to the offset roll is printed on the outer circumferential surface of the shaft, it becomes a groove for generating dynamic pressure on the shaft. A method of forming grooves for generating dynamic pressure on a shaft, characterized by corroding the non-printing part with a corrosive liquid. 2.Equipped with an offset roll that rotates in contact with a shaft, and a printing original roll that rotates in contact with the offset roll, and on the outer peripheral surface of the printing original roll, the printing length from the printing start edge to the printing end is the same as that of the axis. A printing original plate having a length that appropriately exceeds a circumferential length corresponding to one rotation is provided in the circumferential direction, and the printing original plate includes:
Non-image areas in the shape of grooves for dynamic pressure generation and image areas having circumferential contours in the shape of grooves for dynamic pressure generation are alternately connected and arranged in the circumferential direction, and the printing start end A circumferential contour figure of the shape of a groove for generating dynamic pressure provided in the print area on the side and a circumferential contour figure of the shape of the groove for generating dynamic pressure provided in the print area on the printing end side. Both are characterized by having an undivided shape that is approximately equal to the circumferential contour of the groove for generating dynamic pressure provided in the central image area between the printing start end and the printing end. A device that forms grooves for generating dynamic pressure on the shaft.