JP2008221448A - Doctor blade polishing device and method of polishing doctor blade - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a doctor blade polishing device such that the defect of printing and the change of darkness of printing with time are eliminated by eliminating the nonuniformity of polishing by a doctor blade abrasive powder produced by the polishing operation of a doctor blade. <P>SOLUTION: This doctor blade polishing device polishes the doctor blade 100 of a doctor for scraping off an ink excessively supplied onto the surface of the plate cylinder of a photogravure. The doctor blade polishing device comprises: a polishing portion formed on the peripheral surface of a cylinder grinding wheel 50 similar to the outer shape of a gravure cylinder; a rotatingly driving means for rotatingly driving the cylinder grinding wheel 50; a means 20 for movably supporting the doctor blade 50 and pressing the doctor blade 50 against the polishing portion; and a washing means 200 for washing the polishing portion by jetting a washing fluid. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention belongs to the technical field of gravure printing. In particular, the present invention relates to a doctor blade polishing apparatus for polishing a doctor blade for scraping off ink supplied excessively to the surface of a gravure printing plate cylinder from the plate surface.

  Conventionally, a method in which an operator manually polishes a doctor blade incorporated in a doctor holder by using a grindstone or a file in a printing unit. However, in the manual polishing, the polishing finish varies depending on the skill level of the operator, and the polishing condition varies in the longitudinal direction of the doctor blade. As a result, the print density of the printed matter varies. Furthermore, there is a problem that there is a danger in the polishing operation and that the polishing operation takes time.

Therefore, an invention of a doctor blade polishing apparatus that has a self-propelled polishing head capable of reciprocating along a doctor fixed on a base and automatically polishes a doctor blade is disclosed (Patent Document 1). . However, the polished surface polished using the doctor polishing apparatus and the actual printing plate surface do not coincide with each other, and during printing, the contact area between the doctor blade and the plate surface changes due to wear of the doctor blade, so that the printing density is changed over time. There is a problem of changing.
There has been proposed a printing press provided with a member for polishing a doctor blade at a position having a height difference with respect to a cylinder peripheral surface (Patent Document 2). However, there is a problem in that poor printing quality is caused by mixing of doctor blade wear powder generated by polishing into ink and uneven polishing due to adhesion to the doctor blade.
Moreover, the invention of the cylinder type grindstone which has the grinding | polishing surface for grind | polishing a doctor blade on the surrounding surface of a cylinder type main-body part, and the doctor blade grinding | polishing apparatus and method provided with the said cylinder type grindstone is disclosed (patent document 3). . The surface of the cylinder-type grindstone is a polished surface, and the polished surface can be formed by, for example, manufacturing a cylindrical grindstone, inserting a cylinder, and bonding them. Examples of a method for producing a cylindrical grindstone include a vitrified method, a magnesia method, and a resinoid method. By using these methods, a polished surface is formed, and a fine abrasive grain powder is laid in the polished surface, thereby enabling highly precise doctor blade polishing. However, the abrasive surface formed by these methods does not have a structure in which adjacent abrasive powders are in close contact with each other, and there are fine gaps. The abrasion powder of the doctor blade adheres and remains in this gap, causing uneven polishing. As a result, there is a problem in that poor print quality occurs due to uneven polishing.
JP 04-372350 A Japanese Patent No. 3608276 JP 2006-75926 A

  The present invention has been made to solve the above problems. The purpose is that the skill level of the operator is not required, the polishing work can be completed in a short time, and the contact area between the blade surface and the printing plate surface does not change over time due to wear of the doctor blade edge, so the printing density does not change over time. The object is to prevent print quality defects caused by mixing of abrasion powder generated by polishing into ink and uneven polishing due to remaining abrasion powder. And it is providing the doctor blade grinding | polishing apparatus etc. for that.

According to a first aspect of the present invention, there is provided a doctor blade polishing apparatus for rotating a polishing portion for polishing the doctor blade, which is provided on a peripheral surface of a cylinder type grindstone similar to the outer shape of a gravure cylinder, and the cylinder type grindstone. Rotation drive means, means for movably supporting the doctor blade, pressing the doctor blade against the polishing portion, and cleaning means for cleaning the polishing portion are provided.
A doctor blade polishing apparatus according to claim 2 of the present invention is characterized in that, in the doctor polishing apparatus according to claim 1, the polishing portion is a polishing surface to which polishing abrasive particles are fixed.
A doctor blade polishing apparatus according to a third aspect of the present invention is the doctor blade polishing apparatus according to the first or second aspect, wherein the cleaning means is installed parallel to the longitudinal direction of the cylinder type grindstone, The doctor blade polishing apparatus according to claim 4 of the present invention rotationally drives a cylinder-type grindstone that resembles the outer shape of a gravure cylinder. And a step of movably supporting the doctor blade and pressing the doctor blade against the polishing portion, and a step of cleaning the polishing portion by spraying a cleaning liquid.
A doctor blade polishing method according to a fifth aspect of the present invention is the doctor blade polishing method according to the fourth aspect, wherein the cleaning step includes a liquid supply pipe installed in parallel with the longitudinal direction of the cylinder type grindstone, and a liquid supply pipe. The cleaning liquid is ejected from at least one cleaning liquid spray nozzle.

According to the doctor blade polishing apparatus according to claim 1 of the present invention, since the rotation driving means for rotating the cylinder type grindstone having the polishing portion on the peripheral surface is provided, the polishing is simultaneously performed over the entire doctor longitudinal direction. This polishing has good reproducibility and can be finished in a short time. Also, by supporting the doctor blade movably and pressing the doctor blade against the grinding part of the peripheral surface of the cylinder type grindstone that resembles the outer shape of the gravure cylinder, the doctor blade's polishing surface matches the printing plate surface that is actually used. In actual printing, the contact angle and the contact area do not change with time. Since the polishing work is performed outside the printing unit, the doctor blade wear powder does not enter the ink. Also provided is a doctor blade polishing apparatus that can provide a printed matter free from printing defects due to polishing unevenness of the doctor blade due to wear powder adhering to the polishing surface and the polishing portion and the doctor blade by providing a cleaning means for removing the wear powder. Is done.
According to the doctor blade polishing apparatus according to claim 2 of the present invention, the polishing surface of the doctor blade coincides with the plate surface actually used, and the contact angle and the contact area do not change with time in actual printing.
According to the doctor blade polishing apparatus according to claim 3 of the present invention, the cleaning liquid is sprayed from the liquid feeding pipe installed parallel to the longitudinal direction of the cylinder-type grindstone and at least one cleaning liquid jet nozzle arranged in the liquid feeding pipe. As a result, the doctor blade wear powder adhering to and remaining on the polished portion can be washed away, and a printed matter free from printing defects can be obtained.
According to the doctor blade polishing method according to claims 4 and 5 of the present invention, the doctor blade abrasion powder adhering to and remaining on the polishing portion of the peripheral surface of the cylinder-type grindstone can be washed away, and a printed matter free from printing defects can be obtained. it can.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing an example of a mode of polishing a doctor blade using a cylindrical grindstone 50 having a polishing portion on the peripheral surface in the doctor blade polishing apparatus of the present invention. FIG. 2 is a top view showing an example of a polishing portion in the doctor polishing apparatus of the present invention. FIG. 3 is a cross-sectional view (AA of FIG. 2) showing an example of a polishing portion in the doctor blade polishing apparatus of the present invention. FIG. 4 is a top view showing an example of the cleaning means in the doctor blade polishing apparatus of the present invention. FIG. 5 is a cross-sectional view (BB ′ in FIG. 4) showing an example of a main cleaning part in the doctor blade polishing apparatus of the present invention.

  The doctor holder 10 is a member that sandwiches the doctor blade 100 between two metal plates. These two metal plates are a holder upper plate 11a and a holder lower plate 11b as shown in FIG. The doctor blade 100 is attached to and detached from the doctor blade polishing apparatus in an integrated state sandwiched by the doctor holder 10. The doctor holder 10 can be used as a dedicated support tool for the doctor blade polishing apparatus, and can be used as a dedicated support tool for a gravure printing machine using the doctor blade 100. Accordingly, it is easy to make the polished surface of the doctor blade coincide with the gravure printing plate surface, and the work load for adjusting and holding the doctor blade 100 on the doctor holder 10 is reduced, which is preferable.

  The doctor mount 20 includes a holding mechanism for holding and fixing the doctor holder 10 and front and rear adjustment mechanisms 30 a and 30 b on the left and right sides of the doctor blade 100.

  The front and rear adjustment mechanisms 30a and 30b are, for example, a threaded rod member that contacts the rear part (side opposite to the blade edge of the doctor blade 100) in the doctor holder 10, and a screw hole fixed to the doctor mount 20 that supports the threaded rod member. It comprises a member and a front / rear adjustment handle 31a, 31b for manually rotating a threaded rod member. The front / rear adjustment mechanisms 30a, 30b have a mechanism for rotating the front / rear adjustment handles 31a, 31b by an operator to bring the doctor blade 100 closer to or away from the cylinder-type grindstone 50.

  The vertical adjustment mechanism 40 is a mechanism for adjusting the vertical position of the doctor mount 20. For example, as the vertical adjustment mechanism 40, a well-known linear movement mechanism, an arm and its rotation mechanism provided between the frame of the doctor blade polishing apparatus and the doctor mount 20 can be applied.

  The above-described front and rear adjustment mechanisms 30a and 30b and the vertical adjustment mechanism 40 perform a polishing operation that satisfies the same contact angle condition as the angle at which the doctor blade 100 contacts the plate surface of the actual printing plate cylinder. As a result, the polished surface of the doctor blade and the actual printing plate surface coincide with each other, and it is possible to eliminate the change with time of the printing density due to the change with time of the contact angle and the contact area between the doctor blade and the plate surface.

  The cylinder-type grindstone 50 is a cylinder or cylinder similar to the outer shape of the gravure printing plate cylinder, and a polishing portion to which polishing abrasive powder is fixed is provided on the peripheral surface, thereby polishing the doctor blade. The cylinder shape may be either a cylinder with a shaft with a shaft or a cylinder without a shaft (sleeve cylinder). When the cylinder-type grindstone 50 is a shaft-equipped cylinder, the doctor polishing device includes a shaft-cylinder bearing. When the cylinder-type grindstone 50 is an axisless cylinder, the doctor blade polishing apparatus is provided with a chucking mechanism including a chucking cone. In any cylinder shape, the doctor blade polishing apparatus includes a rotation mechanism that rotates the cylinder-type grindstone 50 at a predetermined rotation speed.

The cylinder-type grindstone 50 is laid with polishing abrasive powder on the peripheral surface, and the peripheral surface becomes a polishing portion. The abrasive grain powder is spread at a density of, for example, 6000 pieces / inch ² .

  The doctor blade 100 is a thin plate for scraping off ink supplied excessively to the plate surface of the gravure cylinder, and is generally made of metal or ceramic. For example, it has a thickness of 0.01 mm to 1.0 mm and adheres to and adheres to the bending plate surface by pressing.

  The abrasion powder of the doctor blade 100 adheres to the surface of the cylinder-type grindstone 50 by polishing the doctor blade. In the doctor blade polishing apparatus, a cleaning liquid supply pipe 210 disposed in parallel to the cylinder type grindstone 50 provided to face the doctor holder 10 and at least one cleaning liquid injection nozzle 200a, 200b attached to the cleaning liquid supply pipe. , 200c,..., The cleaning liquid 220 is sprayed onto the cylinder-type grindstone 50.

  Although not shown, the cleaning liquid 220 that is sprayed onto the cylinder-type grindstone 50 and removes the doctor blade abrasion powder adhering to the surface of the cylinder-type grindstone 50 is received by a cleaning liquid tray placed below the cylinder-type grindstone 50, and a pump or the like is used. It has a mechanism to circulate and use. At this time, in order to prevent the circulation of the doctor blade wear powder contained in the circulating fluid, a filter is provided in the circulation liquid supply pipe, and the wear powder washed away from the polishing portion is captured and removed.

Next, an example of the operation of the doctor blade polishing apparatus of the present invention in the above configuration will be described with reference to FIG. FIG. 6 is a flow chart showing an example of polishing and cleaning processes in the doctor blade polishing apparatus of the present invention.
First, in step S1 (preparation 1) in FIG. 6, the doctor blade 100 before polishing is fixed to a doctor holder 10 dedicated to a gravure printing machine that will perform printing. The doctor holder 10 on which the doctor blade 100 is held and fixed is attached to the doctor blade polishing apparatus of the present invention. At this time, it is assumed that the cylinder-type grindstone 50 is previously installed in the doctor polishing apparatus. Moreover, when not installing beforehand, mounting | wearing to the doctor blade grinding | polishing apparatus of the cylinder type grindstone 50 shall be performed before this step.

  In step S2 (setting polishing conditions), the operator sets polishing conditions excluding the polishing angle in the doctor blade polishing apparatus. The polishing conditions include doctor pressure, polishing time, rotation speed of the cylinder-type grindstone 50, and the like.

  In step S3 (polishing angle setting), the operator sets the polishing angle in the doctor blade polishing apparatus. The polishing angle is set so that the polishing surface of the doctor blade 100 brought into contact with the plate surface when printing is made coincident with the plate surface. The polishing angle is set by adjusting the above-described front and rear adjustment mechanisms 30a and 30b and the vertical adjustment mechanism 40, and adjusting the relative positional relationship between the cutting edge of the doctor blade 100 and the peripheral surface of the cylinder-type grindstone 50. Set.

  In step S4 (polishing), the operator presses the polishing start button on the operation panel of the doctor polishing apparatus. As a result, the cylinder rotation mechanism operates, and the cylinder-type grindstone 50 is accelerated while rotating and reaches a set rotation speed, and then enters a constant speed operation. In this state, the doctor cradle 20 is displaced from the detached position to the worn position, and the doctor blade is brought into contact with the rotating cylinder-type grindstone 50 while being pressed, and the blade edge is polished. The polishing operation is stopped after a certain period of time. This stopping operation may be a flow of decelerating and stopping the rotation speed of the cylinder-type grindstone by putting the doctor blade at the landing position in the disengaged state and applying a brake to the rotation mechanism, or vice versa. In terms of work efficiency, if the doctor blade returns to the detached position, the cylinder type grindstone 50 may move to the next step while maintaining the rotation state.

  In step S5 (doctor removal), the operator removes the doctor holder 10 on which the doctor blade is held and fixed from the doctor blade polishing apparatus of the present invention. Since the abrasion powder adheres to the polished surface of the doctor after the polishing operation by the polishing in the above step, the abrasion powder is removed by wiping with a nonwoven fabric or the like.

  In step S6 (preparation 2), the operator determines the injection pressure and the injection time, and presses the cleaning start button on the operation panel of the doctor polishing apparatus. As a result, the cleaning liquid is jetted from the jet nozzles 200a, 200b, 200c,... Toward the cylinder-type grindstone 50 in the rotating state (after the step S5 when it is in the stopped state, the rotation of the cylinder-type grindstone 50 is started). The operation of the pump and the like related to the circulation of the cleaning liquid is started. Examples of the cleaning liquid include water filtered through a filter and the like.

  In step S7 (cleaning), the cleaning liquid is sprayed from the spray nozzles 200a, 200b, 200c... The doctor blade wear powder adhering to the circumferential surface of the cylinder type grindstone 50 is washed away by the cleaning liquid sprayed from the spray nozzles 200a, 200b, 200c. The cleaning liquid once used for cleaning is received by a cleaning liquid tray placed below the cylinder-type grindstone 50 and is used in a circulating manner. The circulation liquid supply pipe is provided with a filter to capture and remove wear powder contained in the collected cleaning liquid as needed. Here, the term “cleaning” refers to removing doctor blade polishing abrasion powder adhering to the polishing portion and removing dirt on the peripheral surface of the cylinder-type grindstone.

  In step S8 (operation stop), the operator presses the stop button on the operation panel of the doctor blade polishing apparatus. As a result, the ejection of the cleaning liquid and the operation of the rotation driving means are stopped. Moreover, the mechanism which sets the washing | cleaning time beforehand and stops automatically by a timer function may be sufficient.

  By the above steps, polishing of the doctor blade 100 held by the doctor holder 10 is completed, and a polishing surface that matches the actual printing plate surface is formed on the blade edge of the doctor blade. Moreover, the abrasion powder of the doctor blade adhering to the polishing portion provided on the circumferential surface of the cylinder type grindstone 50 is removed by the cleaning means. Therefore, the variation in the degree of polishing of the doctor blade polishing surface can be eliminated, and gravure printing without quality defects becomes possible.

It is the schematic which shows an example when grind | polishing using a cylinder type grindstone in the doctor blade grinding | polishing apparatus of this invention. It is a top view which shows an example of the grinding | polishing part in the doctor blade grinding | polishing apparatus of this invention. It is sectional drawing which shows an example of the grinding | polishing part in the doctor blade grinding | polishing apparatus of this invention. It is a top view which shows an example of the washing | cleaning means in the doctor blade grinding | polishing apparatus of this invention. It is sectional drawing which shows an example of the washing | cleaning means in the doctor blade grinding | polishing apparatus of this invention. It is a flowchart which shows an example of the process of grinding | polishing and washing | cleaning in the doctor grinding | polishing apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Doctor holder 11a Holder upper plate 11b Holder lower plate 20 Doctor mount 30a, 30b Front / rear adjustment mechanism 31a, 31b Front / rear adjustment handle 40 Vertical adjustment mechanism 50 Cylinder-type grindstone 100 Doctor blade 200 Cleaning liquid injection nozzle 210 Cleaning liquid supply pipe 220 Cleaning liquid

Claims (5)

In the doctor blade polishing device that polishes the doctor blade of the doctor for scraping off the excessive ink supplied to the surface of the gravure printing plate cylinder,
A polishing portion provided on the peripheral surface of a cylinder-type grindstone similar to the outer shape of a gravure cylinder;
Rotation driving means for rotating the cylinder type grindstone,
Means for movably supporting the doctor blade and pressing the doctor blade against the polishing portion;
A doctor blade polishing apparatus comprising: cleaning means for cleaning the polishing portion by spraying a cleaning liquid.   The doctor blade polishing apparatus according to claim 1, wherein the polishing portion is a polishing surface to which polishing abrasive grains are fixed. A liquid feed pipe in which the cleaning means is installed in parallel with the longitudinal direction of the cylinder-type grinding wheel;
The doctor blade polishing apparatus according to claim 1, further comprising at least one cleaning liquid jet nozzle disposed in the liquid feeding pipe. In the doctor blade polishing method for polishing the doctor blade of the doctor for scraping off the excessive ink supplied to the surface of the gravure printing plate cylinder,
A step of rotating and driving a cylindrical grindstone similar to the outer shape of a gravure cylinder;
Supporting the doctor blade movably and pressing the doctor blade against the polishing portion;
A doctor blade polishing method comprising the step of cleaning the polishing portion by spraying a cleaning liquid.   The cleaning step is performed by a liquid feeding pipe installed parallel to the longitudinal direction of the cylindrical body portion and a cleaning liquid ejected from at least one cleaning liquid ejection nozzle disposed in the liquid feeding pipe. Item 5. The doctor blade polishing method according to Item 4.

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