JP2006315399A - Surface-treated doctor blade - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-treated doctor blade capable of improving intimacy of the edge of a blade, improving the abrasion resistance itself of the edge of the blade, and decreasing the frequency of interchange of the blade. <P>SOLUTION: The surface-treated doctor blade has no uneven part whose size in the plane direction exceeds 50 μm, and is provided with a film consisting of a nickel-phosphor alloy. It is preferable that the uneven parts have those whose sizes in the plane direction exceed 30 μm are at most 20 per 1 m in the length direction, and it is more preferable that the uneven parts whose sizes in the plane direction exceed 20 μm are at most 10 per 1 m in the length direction, and it is especially preferable that uneven parts whose sizes exceed 10 μm are at most 5 per 1 m in the length direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a doctor blade that has been subjected to a surface treatment, and more specifically, when the doctor blade is replaced, the amount of idling performed to adjust the contact between the blade edge and the cylinder can be reduced, and The present invention relates to a surface-treated doctor blade excellent in wear resistance of a cutting edge.

  In the case of gravure (intaglio) printing, as shown in FIGS. 1 and 2 (both FIGS. 1 and 2 are drawn with the blade portion extremely enlarged relative to the cylinder for easy understanding), an image is formed on the cylindrical surface. Using a cylinder (1) formed with a large number of minute recesses (not shown) called cells corresponding to, a steel or stainless steel doctor blade (2) is pressed against the circumferential surface of the cylinder with a constant pressure. The ink (3) adhering to the non-image part of the printing plate is scraped off and removed. Since this doctor blade has the function of completely removing the ink in the non-image area and leaving a predetermined amount of ink in the image area, the contact pressure between the cylinder and the doctor blade must always be kept constant. However, the cutting edge is required to have wear resistance, and various surface treatment doctor blades are used.

  For example, as a surface-treated doctor blade by nickel-based plating, composite plating (5) in which SiC fine particles are dispersed in a nickel-based metal (more specifically, nickel-phosphorous alloy) matrix with respect to the blade base (4). However, such a surface-treated doctor blade has a blade tip (6) completely covered with plating as shown in FIG. If printing is performed immediately after a new replacement, printing defects such as streaks and fogging are likely to occur. Therefore, it is usual to perform actual printing after performing the idling operation for 30 minutes to 60 minutes to improve the contact (familiarity) between the cylinder and the blade. However, this has the problem that not only the loss of the idle operation time is generated and the printing efficiency becomes very bad, but also the cylinder is damaged during the idle operation and the blade is unevenly worn (hereinafter referred to as “blank”). These problems are collectively referred to as “edge adaptability”.)

  Therefore, the inventors of the present invention previously described in Patent Document 1 are made of a surface treatment film consisting of a specific nickel-based plating as the first layer and a low surface energy film of the second layer thereon, and the tip of the cutting edge. A surface-treated doctor blade characterized in that at least a part of the blade substrate is exposed.

JP 2003-225988 A

  However, although this blade is effective in improving the edge adaptability, the blade edge is compared with the surface-treated doctor blade where the substrate is not exposed because the substrate is exposed at the tip cylinder contact portion. The wear rate is high, and the performance from the viewpoint of simple blade wear is inferior. Therefore, in normal printed matter that does not require very high printing characteristics, the wear speed of the blade edge is inversely proportional to the printing amount during continuous printing, so that the blade edge easily wears (those with a fast wear speed) There is a problem in that the frequency of blade replacement is high (the blade life is short) and the continuous printability is poor.

  Therefore, the object of the present invention is to improve the above-mentioned problems of the prior art, improve the adaptability of the blade edge, improve the wear resistance of the blade edge, and reduce the frequency of blade replacement. It is to provide a treatment doctor blade.

As a result of earnestly examining methods other than the technique of Patent Document 1 in order to improve the adaptability of the blade edge in gravure printing, the present inventors have found that the shape (unevenness) of the plating surface at the tip of the blade edge is compatible with the blade edge. It was found that a surface-treated doctor blade that greatly contributes and does not have irregularities of a certain shape or more can greatly improve the conformability of the blade edge without deteriorating the wear resistance.
That is, this invention consists of the following structures.

[1] A surface-treated doctor blade provided with a coating made of a nickel-phosphorus alloy that does not have an uneven portion with a size in the surface direction exceeding 50 μm at least at the tip of the doctor blade.
[2] The surface-treated doctor blade according to 1 above, wherein the nickel-phosphorus alloy film has a liquid film layer containing at least one atom selected from sulfur, nitrogen and phosphorus on the upper layer.
[3] The surface-treated doctor blade according to 2 above, wherein the liquid film layer has a thickness of less than 1 μm.
[4] In any one of the above items 1 to 3, wherein at least the tip of the doctor blade has 20 or less irregularities having a size in the surface direction exceeding 30 μm and 50 μm or less per 1 m in the length direction of the long blade. Surface treatment doctor blade.
[5] In any one of the above items 1 to 3, wherein at least the tip of the doctor blade has 10 or less irregularities having a size in the surface direction of more than 20 μm and 50 μm or less per 1 m in the length direction of the long blade. Surface treatment doctor blade.
[6] In any one of the above items 1 to 3, wherein at least the tip of the doctor blade has 5 or less irregularities with a size in the surface direction exceeding 10 μm and 50 μm or less per 1 m in the length direction of the long blade. Surface treatment doctor blade.

Hereinafter, the present invention will be described in detail.
As the doctor blade substrate used in the present invention, any known steel and / or stainless steel substrate used for printing and painting can be used.

  In addition, the doctor blade base material is usually processed such as being stepped and formed so that the side edge serving as the blade edge becomes a thin blade shape, and parallel blades and inclined blades depending on the shape of the blade There are round blades and square blades, and any shape can be used. In addition, there is a single-edged type that performs such cutting edge processing only on one side of the blade, and a double-edged type that is performed on both sides. In the present invention, either type can be used depending on the application. .

  In the present invention, the blade base material dimensions can be used without any limitation. For example, a typical blade base material is formed of a strip steel plate having a thickness of 0.15 mm to 0.6 mm and a width of 40 to 60 mm.

  The surface-treated doctor blade of the present invention has the greatest feature in that at least the tip of the doctor blade does not have an uneven portion with a size in the surface direction exceeding 50 μm.

  As shown in FIGS. 2 and 3, the blade tip portion is a tip surface near the blade tip from the blade side surface (upper surface) tip piece to the blade other surface (lower surface) tip piece via the blade tip. Point to part (6). In this invention, it is made for the surface part to prevent the uneven | corrugated | grooved part which the magnitude | size of a surface direction exceeds 50 micrometers among the uneven | corrugated | grooved parts (7).

  As shown in FIG. 3, the unevenness having a size in the plane direction exceeding 50 μm means a three-dimensional unevenness such as depth / protrusion in the film thickness direction with respect to the plating surface of the blade tip portion. Not to say, it refers to the size of the two-dimensional unevenness in the surface direction on the plating surface of the blade tip, and when the unevenness has a complicated shape, it refers to the long side portion L of the unevenness portion. .

In the present invention, the presence or absence of the concavo-convex portion can be determined by observing the plating surface at the tip of the blade edge with an optical microscope from the direction indicated by the arrow in FIG. Moreover, the uneven | corrugated | grooved part here means the unevenness | corrugation of the range which can be discriminate | determined by observation with an optical microscope.
More specifically, the unevenness means an unevenness in which the maximum amount of depressions or protrusions in the film thickness direction is 50% or more with respect to the average plating film thickness, and the size of the unevenness in the surface direction is relative to the average plating film thickness. 10% or more of the dent or protruding portion was measured. The measurement can be performed, for example, by creating a three-dimensional shape of the plating surface using a laser microscope, or directly observing the blade cross section with an optical microscope or an electron microscope.

  If there is even one concavo-convex part exceeding 50 μm, it will be necessary to perform idle operation for a long time to adapt the blade edge, and this will result in significant wear of the blade edge due to this idle operation (consuming the blade edge unnecessarily) As a result, the effective cutting edge at the time of actual printing is shortened and the continuous printing amount is reduced.

Furthermore, in addition to the above conditions, it is preferable that the number of uneven portions on the plating surface is not more than 30 μm and not more than 50 μm per blade of 20 μm, more preferably not more than 10. More than 20 μm and 50 μm or less are more preferable per 10 m of blade, more preferably 5 or less, particularly preferably 10 μm or more and 50 μm or less per 5 m of blade.
There are no restrictions on the unevenness having a size outside the specified range.

  Thus, the adaptability of the blade edge is improved by making the shape of the plating surface of the blade tip cylinder contact portion a specific shape. Moreover, in the specific shape of this invention, since the blade front-end | tip surface is plated, the abrasion resistance of a blade edge like patent document 1 does not deteriorate.

The plating used in the present invention is nickel-phosphorus alloy plating, preferably organic resin particles made of fluorine resin in a nickel-phosphorus alloy matrix, Al ₂ O ₃ , Cr ₂ O ₃ , Fe ₂ O. ₃ , TiO ₂ , ZrO ₂ , ThO ₂ , SiO ₂ , CeO ₂ , BeO ₂ , MgO, CdO, diamond, SiC, TiC, WC, VC, ZrC, TaC, Cr ₃ C ₂ , B ₄ C, BN, ZrB ₂ , nickel-phosphorus based dispersion plating in which at least one kind of particles selected from TiN, Si ₃ N ₄ , WSi _{2 and the} like are dispersed.

  Among these particle-dispersed nickel-phosphorus alloy plating, those in which ceramic particles are dispersed, particularly nickel-phosphorus alloy plating in which SiC particles are dispersed, are preferable.

  The particle size of the dispersed particles used is preferably 0.05 μm to 5 μm. When the particle diameter is less than 0.05 μm or more than 5 μm, the wear resistance or plating adhesion is inferior. A preferable particle diameter is 0.1 μm to 2 μm, and a more preferable particle diameter is 0.15 μm to 1 μm.

  The content of the dispersed particles during plating is preferably 0.5 vol% to 40 vol% during plating. If it is less than 0.5 vol%, the effect of improving the wear resistance cannot be obtained, and if it exceeds 40 vol%, the adhesion of the plating is inferior, which is not preferable. The particularly preferred content is 3 vol% to 30 vol%, more preferably 5 vol% to 25 vol%.

  The phosphorus content in the nickel-phosphorous alloy plating layer is preferably 5 to 10% by mass, more preferably 7 to 9% by mass.

In the doctor blade of the present invention, the surface hardness of the blade surface treatment portion is preferably 400 to 1500 in terms of Vickers hardness (Hv). When the Vickers hardness is less than 400, the wear resistance is inferior, and when it exceeds 1500, the blade edge conformability is inferior, the plating is brittle and easily peeled off, and the cylinder plate surface is damaged and printing defects are likely to occur. Particularly preferred Vickers hardness (Hv) is 700 to 950 from the viewpoint of blade fit-in and wear resistance.
In this specification, the Vickers hardness (Hv) is measured in accordance with the Vickers hardness test of the microhardness test method of JIS Z 2251 (the test load is a load of less than 50 gf depending on the film thickness). Can also be selected and used as appropriate.)

The film thickness of the nickel-phosphorous alloy plating layer in the present invention is preferably 3 μm to 20 μm, more preferably 3 μm to 10 μm.
A known measuring method can be used as a method for measuring the plating thickness. For example, (1) a method of measuring a film thickness using a fluorescent X-ray measuring apparatus, (2) a method of peeling a surface treatment film with a stripping solution, and measuring a film thickness by a weight difference before and after that, (3) vertical There is a method of observing the cross section with an optical microscope or an electron microscope and measuring the plating thickness, and these known techniques may be appropriately selected.

  In the present invention, the wear resistance and corrosion resistance can be further improved by providing a liquid film layer containing at least one atom selected from sulfur, nitrogen and phosphorus on the upper layer of the plating layer. The film of the plating upper layer is preferably less than 1 μm in thickness, and more preferably less than 0.5 μm.

  As described above, the surface-treated doctor blade of the present invention has both the adaptability and wear resistance of the blade edge by making the plating surface shape of the contact portion with the blade tip cylinder a specific plating surface shape. The effect of improving can be acquired.

  The surface treatment blade of the present invention can be produced by a known method, but the surface treatment requires strict process control.

  For example, degreasing → washing → activation treatment → water washing → nickel-phosphorus alloy plating → water washing → drying → annealing → blade edge inspection (in some cases, the edge of the blade edge by polishing the edge to make the plating surface shape a predetermined shape) Adjustment) and surface preparation by surface polishing may be performed in these production steps, or the annealing step may be omitted. In addition, the step of blade edge inspection (in some cases, blade edge adjustment by blade edge polishing for making the plating surface shape of the blade edge tip portion a predetermined shape) may be performed before the annealing step.

In a series of plating processes, for example, it is necessary to perform process management in consideration of the following points. By comprehensively performing these process controls, it becomes easy to make the irregularities at the tip of the blade tip into a specific shape defined in the present invention.
(1) The acid concentration of the activation treatment is controlled to a predetermined concentration and soaking is not performed for a long time. That is, the unevenness of the plating due to the roughness of the material is prevented.
(2) Immediately after activation treatment, wash with water and perform plating treatment, and leave it in the air (moving time between processes) so as not to lengthen the time. That is, plating unevenness due to material erosion and rust is prevented.
(3) When using sodium hydroxide as the pH adjuster of the plating solution, add the adjuster in a place where stirring is strong, or dilute the adjuster in advance and replenish with a thin concentration, and react with nickel ions. Prevents the formation of nickel hydroxide.
(4) Thoroughly filter the plating solution to prevent co-deposition of insoluble materials such as dust, cutting scraps and peeled plating film in the plating solution.
(5) Strictly control the pH of the plating solution so that the pH is out of the control range and the formation of metal hydroxide salt by metal ions at high pH is prevented.

  Furthermore, after plating, the cutting edge inspection process is provided either before or after the annealing process, the plating surface is inspected, and if there are irregularities exceeding the specified range in the present invention, it is automatically done with a buff, sandpaper, etc. Alternatively, the tip of the blade tip is ground by manually polishing the tip of the blade tip.

  As plating means, known plating techniques such as electroplating and electroless plating can be used.

  In the present invention, with the aim of increasing the adhesion between the blade base material and the plating layer or promoting the deposition of the plating film, the base plating by nickel-based plating, copper-based plating or the like is performed in advance as a base treatment for plating. Can be done. In particular, when a stainless steel material is used as the blade base material, nickel-based strike plating is effective as a base plating before plating.

  As an embodiment of the present invention, it suffices that at least the tip of the doctor blade is subjected to the processing according to the present invention, and the present invention does not limit the processing of portions other than the blade tip.

  The surface-treated doctor blade obtained in the present invention can be used for printing applications such as gravure printing, but can also be applied to other applications such as coating applications and residual toner removal applications equipped in image forming apparatuses. . In addition, ink and paint used for printing and painting can be either water-based or oil-based. Furthermore, the inking device of the printing press includes a dove dipping method, a furnisher roller method, and the like, but the blade of the present invention can be used regardless of the inking method as long as it uses a blade.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated, this invention is not limited by the following description. The surface hardness, film thickness, and surface shape of the surface-treated doctor blades according to the examples and comparative examples were measured by the following methods.

[Surface hardness (Vickers hardness)]
Five points were measured under the following conditions, and the average value was defined as Vickers hardness (Hv).
Measuring machine: Shimadzu Corporation HMV-2000,
Measurement conditions: test load 25 gf, holding time 10 seconds.

[Film thickness]
The cross section of the blade edge was observed with an optical microscope, and the plating thickness was measured.

[Surface shape]
The surface of the tip of the blade tip was observed with a laser microscope and an optical microscope, the number of irregularities having a maximum irregularity of 50% or more with respect to the average plating thickness was counted, and the size of the irregularities in the surface direction was measured. The size of the unevenness in the surface direction was a portion having an unevenness of 10% or more with respect to the average plating thickness.

[Surface treatment method]
Plating process:
Plate width 50mm, plate thickness 0.15mm, cutting edge length 1.4mm, cutting edge tip thickness 0.07mm, one side, parallel blade doctor blade steel substrate (steel strip, total length 50m), the surface is uneven by embossing It winds up on a reel with a spacer made of a given metal steel strip, and is immersed in a 50 ° C. alkaline degreasing solution (Pacna RT-T: 60 g / liter) for 15 minutes while being wound on the reel, washed with water, Hydrochloric acid activation treatment was carried out in a hydrochloric acid active solution for 15 minutes and further washed with water. Thereafter, electroless Ni plating solution in which SiC having an average particle size of 0.5 μm is dispersed (Nihon Kanisen Co., Ltd., plating solution, Schuma-SC-80-1: 20 vol%, Schuma-SC-80-4: 2 vol%) was immersed at 87 ° C. until the film thickness reached a predetermined film thickness, was subjected to nickel composite plating containing SiC, washed with water, and then dried. Then, the spacer and the blade were unwound and divided to obtain a SiC particle-containing nickel-phosphorus composite (Ni-P-SiC) plating blade 1.

Surface adjustment process:
The plating blade 1 was buffed to completely remove the plating residue on the surface, and the plating blade 2 was obtained.

Post-processing process:
The plating blade 2 is annealed at 300 ° C. for 1 hour, sheared into strips every 2 m to form a strip plating blade, and then a surface treatment blade is prepared by the methods of Examples 1 and 2 and Comparative Examples 1 and 2. did.

Example 1:
The surface of the tip of the strip plating blade is observed with an optical microscope. If necessary, the surface of the plating tip at the tip of the blade has irregularities with a size of more than 50 μm while polishing with a buff or sandpaper. However, the surface treatment doctor blade of Example 1 was obtained by separating only those having 30 μm or more and 50 μm or less per blade of 10 m or less.
The surface hardness (Hv), film thickness, blade edge conformability and wear resistance of this surface-treated doctor blade were measured and evaluated, and are summarized in Table 1. The blade edge conformability and wear resistance evaluation methods are as follows.

(1) Blade edge conformability Using a printing machine equipped with the blade of Example 1, the oil-based ink is used to perform the idling operation. Immediately after the start, print defects such as streaks, fogging, blurring, and blurring do not occur on the printed matter. It was evaluated by the time until printing was possible.
◎: Less than 5 minutes,
○ +: 5 minutes or more and less than 10 minutes,
○: 10 minutes or more and less than 30 minutes,
Δ: 30 minutes or more and less than 60 minutes,
X: 60 minutes or more.

(2) Abrasion resistance The printing machine equipped with the blade of Example 1 printed 3000 m, then removed the blade from the printing machine, measured the length of the blade edge, and determined the degree of wear of the blade [wear length ] = [Initial cutting edge length] − [After cutting edge length] The evaluation criteria are shown below.
[Evaluation criteria]
A: Wear length of less than 1 mm B: Wear length of 1 mm or more and less than 1.5 mm X: Wear length of 1.5 mm or more

Example 2:
The surface of the edge of the strip plating blade is observed with an optical microscope, and if necessary, the surface shape of the edge of the edge of the blade tip is more than 50 μm while polishing with a buff or sandpaper. In addition, only the surface irregularities of 10 μm or more and 50 μm or less were separated by 3 or less per 1 m of blade, and the surface-treated doctor blade of Example 2 was obtained.
The surface treatment doctor blade was measured for surface hardness (Hv), film thickness, blade edge conformability and wear resistance in the same manner as in Example 1, and the results are shown in Table 1.

Example 3:
The surface of the tip of the strip plating blade is observed with an optical microscope. If necessary, the surface of the plating tip at the tip of the blade has irregularities with a size of more than 50 μm while polishing with a buff or sandpaper. However, the surface treatment doctor blade of Example 3 was obtained by separating only those having a diameter of 30 μm and 50 μm or less from 11 to 20 blades per meter.
The surface treatment doctor blade was measured for surface hardness (Hv), film thickness, blade edge conformability and wear resistance in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 1:
The surface of the edge of the strip plating blade is observed with an optical microscope, and the plating surface shape of the edge tip contact portion other than Examples 1, 2 and 3 is separated from those having at least one unevenness with a size of more than 50 μm. The surface-treated doctor blade of Comparative Example 1 was obtained.
The surface treatment doctor blade was measured for surface hardness (Hv), film thickness, blade edge conformability and wear resistance in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 2:
Only the cutting edge tip of the strip plating blade was polished as shown in FIG. 4 (Patent Document 1 FIG. 3 [A]), and the alloy plating film was removed only at the cutting edge tip to obtain a surface-treated doctor blade of Comparative Example 2.
The surface treatment doctor blade was measured for surface hardness (Hv), film thickness, blade edge conformability and wear resistance in the same manner as in Example 1, and the results are shown in Table 1.

The conceptual diagram of the gravure (intaglio) printing which uses a doctor blade is shown. Sectional drawing which shows the blade tip end part of a blade is shown. An explanatory view for showing a specific shape of a blade tip end part of a blade is shown. Sectional drawing which shows the blade front-end | tip part of the blade produced in the comparative example 2 is shown.

Explanation of symbols

1 cylinder (gravure version)
2 Doctor blade 3 Ink 4 Blade base material 5 Surface treatment film 6 Cutting edge tip 7 Concavity and convexity

Claims (6)

  A surface-treated doctor blade provided with a coating made of a nickel-phosphorus alloy that does not have an uneven portion with a size in the surface direction exceeding 50 μm at least at the tip of the doctor blade.   2. The surface-treated doctor blade according to claim 1, wherein a liquid film layer containing at least one atom selected from sulfur, nitrogen and phosphorus is provided on the upper layer of the nickel-phosphorus alloy film.   The surface-treated doctor blade according to claim 2, wherein the liquid film layer has a thickness of less than 1 μm.   The surface according to any one of claims 1 to 3, wherein at least at the tip of the doctor blade, the number of irregularities having a size in the surface direction exceeding 30 µm and not more than 50 µm is 20 or less per 1 m in the length direction of the long blade. Treatment doctor blade.   The surface according to any one of claims 1 to 3, wherein at least at the tip of the doctor blade, the number of irregularities having a size in the plane direction that exceeds 20 µm and is 50 µm or less is 10 or less per 1 m in the length direction of the long blade. Treatment doctor blade. The surface according to any one of claims 1 to 3, wherein at least at the tip of the doctor blade, the number of irregularities having a size in the surface direction exceeding 10 µm and not more than 50 µm is 5 or less per 1 m in the length direction of the long blade. Treatment doctor blade.

Images