JP2012183809A - Doctor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a doctor device that can easily and properly set a contact angle of a doctor blade without need of a lot of time and skill.SOLUTION: The doctor device is constituted to adjust the installation position of the doctor blade according to change in the diameter when a plate cylinder different by types of the printed product is used. The doctor device includes: a doctor holder that holds the doctor blade; a doctor trestle that holds the doctor holder; the support shaft that supports the doctor trestle; a movable rack that has a guide member that can move this support shaft in parallel to the virtual line that connects the contact points of doctor blades to different plate cylinder diameters; and a means that goes up and down and moves the movable rack.

Description

  The present invention relates to a doctor device used in a gravure printing machine to scrape ink adhering to a peripheral surface of a plate cylinder.

The doctor apparatus is generally used in a printing unit such as a gravure printing machine to scrape off excess ink on the surface of the plate cylinder. This printing unit will be described with reference to FIG. FIG. 4 is a diagram illustrating a configuration example of a printing unit of a gravure printing machine to which a conventional doctor apparatus is attached.
As shown in FIG. 4, in general gravure printing, gravure ink 6 is filled in an ink pan 5, and a cylindrical plate cylinder 3a is rotated with its lower part immersed in an ink solution. Let The ink that adheres to the plate cylinder surface as it rotates and is lifted is scraped off by the doctor blade 7 so that only the ink necessary for printing remains in the cell, and then the substrate 2 is placed in the gap between the plate cylinder and the impression cylinder 1. In the gravure printing method, the ink remaining in the cells is transferred to the substrate by the printing pressure between them.

  In the conventional doctor device, a steel material having a thickness of about 0.15 to 0.30 mm is used for the doctor blade. Structurally, the doctor blade in the form of a strip plate is sandwiched between the doctor holders and fixed. The doctor holder is fixed to the doctor mount, and the doctor blade is pressed against the plate cylinder surface. The doctor cradle can be rotated about the rotation shaft, and the rotation of the doctor gantry allows the doctor blade to contact the plate cylinder.

  In gravure printing, setting the contact angle of the doctor blade with the plate cylinder accurately has a great influence on the print quality. The contact angle of a general doctor blade is considered to be around 60 °, but it is difficult to directly measure the contact angle, so the contact angle is determined in advance by the operator's senses, and then test printing is performed. The current situation is that the optimum contact angle is set by adjusting.

  However, in the conventional method as described above, it cannot be said that the contact angle of the doctor blade can be accurately adjusted, and there is a problem that a difference in the contact angle occurs every time the plate cylinder is replaced. When the diameter of the plate cylinder is changed, it is necessary to adjust by moving or rotating the doctor blade up and down and back and forth in order to maintain a predetermined contact angle. The adjustment of the contact angle of the doctor blade has a great influence on the quality of the printed result, which takes a lot of time and also requires skill, which puts a burden on the operator and is not productive. It was.

  With respect to the above problem, Patent Document 1 proposes a position setting method capable of obtaining reproducibility of doctor blade settings. However, this method has a problem in that the mechanism becomes complicated because it requires automatic adjustment of the height of the doctor mount and manual adjustment of the position in the installation advance / retreat direction.

Japanese Patent Laid-Open No. 2007-13679

The present invention has been made to solve such problems, and a doctor device that can easily and appropriately set the contact angle of a doctor blade without requiring much time and skill. Providing is a challenge.

The invention described in claim 1 of the present invention for solving the above-mentioned problems is a doctor device used in gravure printing, and when a different plate cylinder is used for each type of printing product, the diameter changes. In the doctor device configured to adjust the installation position of the doctor blade in response, a doctor holder that holds the doctor blade, a doctor stand that holds the doctor holder, a support shaft that supports the doctor stand, and the support A doctor comprising a moving rack having a guide member capable of moving in parallel with an imaginary line connecting the contact points of the doctor blades for different plate cylinder diameters, and means for moving the moving rack up and down Device.

  When the plate cylinder having a different diameter is replaced by the doctor apparatus according to the first aspect of the present invention, the support shaft is moved along the guide member of the moving rack to replace the plate cylinder with the central axis of the plate cylinder. Since it is possible to move the doctor blade so that each contact point of the doctor blade to the front and back plate cylinder surfaces is a straight line, setting is easy without changing the contact angle of the doctor blade before and after plate cylinder replacement. be able to. Further, the contact angle can be easily changed by adjusting the position of the moving rack and the rotation angle of the doctor blade around the support shaft.

It is a schematic diagram which shows an example of a structure in the doctor apparatus of this invention. In the doctor apparatus of this invention, it is a schematic diagram which shows operation | movement when moving the position of a support shaft according to a plate cylinder diameter. It is a schematic diagram which shows operation | movement when changing the contact angle of a doctor blade in the doctor apparatus of this invention. It is a schematic diagram of printing units, such as a common gravure printing machine.

Embodiments of the present invention will be described below with reference to the drawings.
An example of the configuration of the doctor apparatus of the present invention is shown in FIG. In FIG. 1, 1 is an impression cylinder, 2 is a base material, 3a is a plate cylinder, 4 is a finisher roll, 5 is an ink pan, 6 is gravure ink, 7 is a doctor blade, 8 is a doctor holder, 9 is a doctor base, 10 is a rack for movement, 11 is a support shaft, and a is a contact angle.

  The doctor blade 7 is held by a doctor holder 8, and the doctor holder 8 is held by a doctor mount 9. The doctor mount 9 is supported by a support shaft 11 and can rotate around the support shaft 11. This rotation is configured so that it can be set to rotate to a preset rotation angle c (see FIG. 3). By this rotation, the doctor gantry 9 can take a state in which the doctor blade 7 is brought into contact with the surface of the plate cylinder 3a and a state in which the doctor blade 7 is separated from the surface.

  The doctor device having the above configuration can preset the contact angle a of the doctor blade 7 to a reference angle of about 60 ° by adjusting the position of the moving rack 10 and the rotation angle c of the doctor blade 7. Next, the support shaft 11 is linearly moved along the guide member of the moving rack 10 until the tip of the doctor blade 7 comes into contact with the peripheral surface of the plate cylinder 3a. By making pressure contact with the plate cylinder 3a with a predetermined pressing force, it is possible to scrape the ink adhering to the plate cylinder surface and rising with the doctor blade 7.

  When the large-diameter plate cylinder 3b shown in FIG. 2 is replaced with a small-diameter plate cylinder 3a in response to changing to a printed product having a different pattern, a new small-diameter plate is transferred by the moving rack 10. By moving the support shaft 11 to a position in contact with the body 3a, the setting can be performed without changing the contact angle a of the doctor blade 7.

  When the contact angle a of the doctor blade 7 is changed as an emergency measure when the color density of the printed matter does not appear, the position of the moving rack 10 and the rotation angle c of the doctor blade about the support shaft 11 are 2 It is necessary to adjust one. In order to reduce the contact angle a, the doctor blade 7 is first moved away from the peripheral surface of the plate cylinder 3a by moving the support shaft 11 in the direction away from the plate cylinder 3a along the guide member of the rack 10 for movement. Next, as shown by a dotted line in FIG. 3, the position of the moving rack 10 is lowered, the rotation angle c of the doctor blade is reduced, and the support shaft 11 is moved along the guide member of the moving rack 10 to the plate cylinder 3a. The tip of the doctor blade 7 is brought into contact with the peripheral surface of the plate cylinder 3a by moving in the contact direction. By doing so, the contact angle a can be changed at a point where the tip of the doctor blade 7 is in contact with the peripheral surface of the plate cylinder 3a before the change. At this time, the contact of the doctor blade 7 is confirmed by equipment capable of confirming that the contact of the doctor blade 7 with respect to the plate cylinder 3a is not shifted before and after the change. In determining the predetermined contact angle a by calculating the correlation between the contact angle a and the position of the moving rack 10 and the rotation angle c of the doctor blade 7 in advance, the position of the moving rack 10 and the doctor blade 7 are determined. It is possible to set from the rotation angle c.

  Although the present invention has been described based on the embodiments, the doctor device of the present invention is not limited to the above embodiments, and various modifications are possible without departing from the spirit of the present invention. is there.

DESCRIPTION OF SYMBOLS 1 ... Impression cylinder 2 ... Base material 3a ... Small diameter printing cylinder 3b ... Large diameter printing cylinder 4 ... Furnisher roll 5 ... Ink pan 6 ... Gravure ink 7 ... Doctor blade 8 ... Doctor holder 9 ... Doctor stand 10 ... For movement Rack 11 ... Support axis a ... Contact angle b ... Elevation angle from the center axis of the plate cylinder c ... Rotation angle of the doctor blade

Claims (1)

  In a doctor device used in gravure printing, when a different plate cylinder is used for each type of printed product, the doctor device configured to adjust the installation position of the doctor blade according to the change in its diameter, A doctor holder that holds the doctor blade, a doctor base that holds the doctor holder, a support shaft that supports the doctor base, and a virtual line that connects the support shafts to the contact points of each doctor blade for different plate cylinder diameters A doctor apparatus comprising: a moving rack having a guide member that can be moved in a moving manner; and means for moving the moving rack up and down.

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