JPH0623967A - Printing device - Google Patents

Abstract

PURPOSE:To provide a printing device which enables ink-transfer in a thin film in a wide range and reduces irrgularity in printing. CONSTITUTION:By providing a servomotor 29 for driving a table 21 for printing, a direct drive motor 33 for driving a plate cylinder 31 and a direct drive motor 36 for driving an anilox roll 34, respectively the plate cylinder 31, the anilox roll 34 and the table 31 are separately driven. Thus, there is no need for interconnecting each drive unit with gears as conventional in practice, and mechanical vibration caused by backlash and the like is thereby improved, whereby irregularity in printing is reduced. Further, the correction of speed irregularity caused by variations in the diameters of rolls, errors on a design and the like can be made because synchronous control becomes possible by providing a control circuit to the servomotor 29 and the direct drive motors 33, 36 and, as a result, irregularity in printing caused by speed irregularity is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus for transferring ink uniformly to a non-water-absorbent substrate in flexographic printing with an extremely thin film thickness.

[0002]

2. Description of the Related Art Conventionally, printing apparatuses have been required to print at high speed and with a uniform film thickness. In recent years, with liquid crystal,
Although the alignment film is printed on the glass substrate by flexographic printing, it is becoming difficult to print with a uniform film thickness because the film thickness is very thin and the printing range is wide. There is a demand for a printing device compatible with.

The above-mentioned conventional printing apparatus will be described below with reference to the drawings. FIG. 3 is a configuration diagram of main parts in a conventional printing apparatus. In FIG. 3, the pinion gear 2 to which the drive motor 1 is connected is meshed with the rack 3,
By rotating the pinion gear 2, the rack 3 can be driven in the arrow A direction. A table 4 is fixed and placed on the rack 3, and a substrate 5 which is an object to be printed is fixed and placed on the table 4 by vacuum suction.

A rubber plate 7 for printing is fixed to the peripheral portion of the plate cylinder 6. In addition, anilox roll 8
Transfers the ink to plate 7. The rubber doctor roll 9 spreads the ink evenly over the anilox roll 8 and scrapes off the excess ink. The plate cylinder 6, the anilox roll 8 and the doctor roll 9 are all arranged in parallel in the axial direction, and the plate 7 and the anilox roll 8 and the anilox roll 8 and the doctor roll 9 are pressed against each other with a constant pressing force. . Further, the cylinder unit 10 supplies an appropriate amount of ink to the anilox roll 8.

Further, the gear 11 is attached to the shaft of the pinion gear 2, the gear 12 is attached to the roll shaft of the plate cylinder 6, and the gear 13 is attached.
Is attached to the roll shaft of the anilox roll 8, and the gear 14 is attached to the roll shaft of the doctor roll 9. These gear 11 and gear 12, gear 12 and gear 13, gear 13
And gear 14 mesh with each other, and each gear 11, 12, 1
By transmission of 3 and 14, plate cylinder 6 and anilox roll 8
Furthermore, the doctor roll 9 is configured to rotate.

The operation of the conventional printing apparatus configured as described above will be described below. First, the substrate 5 is set on the table 4 based on the position of the plate 7 attached to the plate cylinder 6. Next, when the drive motor 1 is operated, the pinion gear 2 and the gear 11 are rotated to convey the substrate 5 together with the table 4 through the rack 3 in the direction of the plate cylinder 6 (direction of arrow A), and the gear 11 is moved. Since the gears 12, 13 and 14 attached to the rolls interlock with each other, the plate cylinder 6, the anilox roll 8 and the doctor roll 9 also rotate.

Here, an appropriate amount of ink is supplied to the anilox roll 8 by the cylinder unit 10. Then, when the table 4 is moved to directly below the plate cylinder 8, the substrate 5
Printing is started by pressing against the plate 7. Further, when the table 4 continues to move and passes through the plate cylinder 6, printing is completed. The printed substrate 5 is taken out, the drive motor 1 is rotated in the reverse direction, and the table 4 and the plate 7 are returned to the initial positions.

[0008]

However, in the above-mentioned conventional structure, the pinion gear 2, the rack 3, and the gears 11, 1 are provided.
Backlashes of 2, 13, and 14 tend to cause mechanical vibration and uneven printing. Further, even if a speed deviation occurs due to variations in the diameter of each roll or a design error, speed correction cannot be performed because the gear is driven, and the deviation causes printing unevenness.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a printing apparatus capable of printing in a wide range and having less printing unevenness, corresponding to thinning.

[0010]

In order to solve the above-mentioned problems, a printing apparatus of the present invention comprises a plate cylinder on which a printing plate is mounted and which is rotatably supported, and a shaft end of the plate cylinder. A first motor for rotationally driving the plate cylinder; an anilox roll disposed in parallel with the plate cylinder in the axial direction to contact the plate of the plate cylinder to transfer ink to the plate; and an axis of the anilox roll. A second motor that is attached to the end and drives the anilox roll to rotate, is arranged in parallel to the anilox roll in the axial direction, and is connected to the anilox roll through a gear, and contacts the anilox roll to contact the ink. And a drive unit that is installed below the plate cylinder and that conveys an object to be printed to a position where the plate cylinder contacts the plate.

[0011]

With the above construction, the plate cylinder, the anilox roll and the drive unit are driven separately,
It is no longer necessary to connect each drive unit with gears as in the past, so mechanical vibration due to gear backlash etc. can not occur, and because it is not the conventional gear drive, there are variations in roll diameter and design The speed deviation due to an error or the like can be corrected by controlling each motor, and thin film printing with less printing unevenness can be performed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a main part of a printing apparatus according to an embodiment of the present invention. In FIG. 1, table 21
The substrate 22, which is the material to be printed, is fixed and mounted on the substrate by vacuum suction. Bracket 2 on base plate 23
4 and 25 are erected at a constant interval, a linear guide 26 of the table 21 is provided between the brackets 24 and 25, and a ball screw 27 is rotatably installed around the axial direction. This ball screw 27 has a ball screw
A nut 28 screwed with the screw 27 is provided, and the nut 28 is attached to the lower surface of the table 21. In addition, the bracket 24
Servo motor 29 is attached to this servo motor
29 is connected to the ball screw 27, and the ball screw 27 is rotationally driven by the drive of the servomotor 29. The table 21, the base plate 23, the brackets 24 and 25, the linear guide 26, the ball screw 27, the nut 28, and the servomotor 29 constitute a table drive unit 30.

A printing plate 32 made of rubber for printing is fixed to a plate cylinder 31 which is provided above the table drive unit 30 and is rotatably supported. Direct drive motor
A plate 33 is attached to the roll shaft end of the plate cylinder 31 to rotate the plate cylinder 31. The anilox roll 34 also transfers ink to the plate 32. A gear 35 is attached to the roll shaft of the anilox roll 34, and a direct drive motor 36 is attached to the end of the roll shaft. Further, the rubber doctor roll 37 spreads the ink evenly over the anilox roll 34 and scrapes off the excess ink. A gear 38 is attached to the roll shaft of the doctor roll 37, and when the anilox roll 34 rotates, the doctor roll 37 is rotated in the opposite direction to the anilox roll 34 by the gears 35 and 38. These plate cylinder 31, anilox roll 34
And the doctor roll 37 are all arranged in parallel, and the plate 32 and the anilox roll 34 and the anilox roll 34 and the doctor roll 37 are pressed against each other with a constant pressing force. Further, the cylinder unit 39 is configured to supply ink to the anilox roll 34 in a fixed amount.

The operation of the printing apparatus configured as described above will be described below. First, the substrate 22 is set on the table 21 with the plate 32 attached to the plate cylinder 31 as a reference.
Ink is periodically dropped onto the anilox roll 34 from the ink supply cylinder unit 39. Next, the servo motor 29 and the direct drive motors 33 and 36 are operated. The starting position of the table 21 is the plate cylinder 31
When transported to the direction of and moved right below the plate cylinder 31,
Control is performed by controlling the servo motor 29 so that the plate 32 and the substrate 22 come into pressure contact with each other. Furthermore, in order to prevent uneven printing, the moving speed of the table 21, the peripheral speed of the plate 32, and the peripheral speed of the anilox roll 34 are electrically controlled to be equal.

When the servo motor 29 is driven in this way, the table 21 is guided by the linear guide 26 via the ball screw 27 and the nut 28 to move in the horizontal direction, and the substrate 22 is moved.
To transport. Printing starts when the table 21 and the plate 32 move and the substrate 22 and the plate 32 come into pressure contact with each other.
However, the printing is completed when the plate cylinder 31 is completely moved while keeping the relative speed with the plate 32 constant. Then, the plate cylinder 31 continues to rotate as it is and stops when it returns to the initial position. Further, after the printed substrate 22 is taken out, the servo motor 29 is reversely rotated to return the table 21 to the initial position.

FIG. 2 is a block diagram of a motor control system in the printing apparatus of FIG. In FIG. 2, a direct drive motor 36 for driving an anilox roll incorporates a resolver 41 for detecting a position and a motor rotation speed, and a servo motor 33 for driving a plate cylinder has a position and a motor rotation speed. A resolver 42 for detecting the Also, servo motor for table drive
An encoder 43 for detecting the position and the motor rotation speed is incorporated in 29. Each of these drive motors 2
The command controller 44, 45, and 46 set the stop position and rotation speed to 9, 33, and 36 to issue commands. Servo amplifier 47, in response to commands from these command controllers 44, 45, 46
The respective drive motors 29, 33, 36 rotate via the respective 48, 49, and the speed is corrected by the detection of the resolvers 41, 42 and the encoder 43. The reference speed is the value V calculated by the resolver control circuit 50 connected to the resolver 42.
_{Based on 0} .

When the value calculated by the resolver control circuit 51 connected to the resolver 41 is V ₁ and the value calculated by the encoder control circuit 52 connected to the encoder 43 is V ₂ , anilox is given. The speed of the roll 34 and the plate cylinder 31 is corrected by V ₀ -V ₁ of the speed difference calculation circuit 53.
The value obtained from the calculated value of X ₁ is the command controller
Feedback to 44 and make corrections. Similarly, the speed correction between the plate cylinder 31 and the table 21 is performed by V ₀ -V of the speed difference calculation circuit 54.
_The value obtained from the calculated value of ₂ = X ₂ is fed back to the command controller 46 for correction.

Further, the drive start of the table 21 is synchronized by sending a rotation start command of the plate cylinder 31 to the command controller 46. Reference numeral 55 is an amplifier interposed between the resolver control circuit 50 and the command controller 46.
7 and 58 are adders for adding the position signals, and 5
Reference numerals 9, 60, 61 are adders for adding speed signals.

As described above, the servo motor 29 for driving the printing table 21, the direct drive motor 33 for driving the plate cylinder 31, and the direct drive motor 36 for driving the anilox roll 34 are provided. Torso 3
1. By separately driving the anilox roll 34 and the table 21, it is not necessary to connect each drive unit with a gear as in the conventional case, mechanical vibration due to backlash and the like is improved, and uneven printing is reduced.
In addition, correction of speed deviation due to variations in roll diameter and design errors can be controlled synchronously by providing a control circuit in the servo motor 29 and direct drive motors 33 and 36, so uneven printing due to speed deviation can be suppressed. To be

Therefore, in flexographic printing, when an extremely thin film thickness is uniformly printed on a printing material, mechanical vibration or speed deviation causes printing unevenness, but eliminates the mechanical vibration or speed deviation. As a result, thin film printing with less printing unevenness can be realized.

[0021]

As described above, according to the present invention, the drive unit, the plate cylinder, and the anilox roll are independently driven, so that mechanical vibration can be suppressed and synchronous control can be performed for each operation. The speeds can always be made equal, and therefore a stable thin print film with less printing unevenness can be realized.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a main part of a printing apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram of a motor control system in the printing apparatus of FIG.

FIG. 3 is a configuration diagram of main parts in a conventional printing apparatus.

[Explanation of symbols]

 21 table 22 substrate 23 base plate 24, 25 bracket 26 linear motion guide 27 ball screw 28 nut 29 servo motor 30 table drive unit 31 plate cylinder 32 plate 33, 36 direct drive motor 34 anilox roll 35, 38 gear 37 doctor roll

Claims (1)

[Claims] 1. A plate cylinder on which a printing plate is mounted and which is rotatably supported, a first motor mounted on the shaft end of the plate cylinder to drive the plate cylinder to rotate, and the plate cylinder and shaft. An anilox roll arranged parallel to the direction and abutting against the plate of the plate cylinder to transfer ink to the plate; and a second motor attached to the shaft end of the anilox roll to drive the anilox roll to rotate. A doctor roll, which is arranged parallel to the anilox roll in the axial direction and is connected to the anilox roll via a gear, spreads ink by contacting the anilox roll, and is installed below the plate cylinder. And a drive unit that conveys an object to be printed to a position where the plate comes into contact with the printing plate.