JPH0872217A - Ink spreading method and apparatus and printing press - Google Patents

Abstract

PURPOSE: To realize printing of high accuracy and high quality without receiving the effect of the ink bonded to the tip part of a doctor. CONSTITUTION: When a scraping-off member 7 is moved to the left in such a state that a doctor is separated from a lower printing plate, the scraping-off member 7 moves in a longitudinal direction while comes into contact with the edge of the doctor 4. Therefore, the ink bonded to the edge part of the doctor 4 can be removed by the scraping-off member 7 to be gathered to an ink recovery container 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for spreading ink in an offset printing apparatus for printing a pattern on a substrate such as a color filter.

[0002]

2. Description of the Related Art Conventionally, for example, as a technique for printing a pattern on a color filter used in a liquid crystal image receiver,
Although various methods are known, an offset printing apparatus is generally used.

In offset printing, first, ink is supplied to a printing plate by a dispenser or the like, and then ink is spread by a doctor to fill the pattern grooves of the printing plate with ink.

Thereafter, the blanket is rolled on the printing plate to transfer the printing ink pattern onto the blanket surface. Then, the blanket is rolled on the printing medium to print the printing ink pattern.

Due to such a printing principle, in order to perform good offset printing, it is necessary to remove excess ink other than the pattern grooves with a doctor.

Here, the mechanism of ink spreading by the doctor is that when the doctor slides on the printing plate while making pressure contact, the doctor imparts a shearing stress to the ink to lower the viscosity of the ink and to cause a lump of ink. Rolling is caused at the same time, and at the same time, the doctor generates pushing force into the groove (see, for example, Manabu Harada, "Measurement of solder paste viscosity and adhesive force", HYBRIDS, Vol 8, No. 2).

However, when the excess ink collects between the doctor and the printing plate, the surplus ink slides up along the blade edge of the doctor. Then, when the doctor leaves the printing plate after the ink spreading operation, most of the excess ink is pulled up while being attached to the doctor, and an ink pool is formed at the doctor blade edge.

[0008]

In the above-mentioned doctor method, the ink adhering to the doctor blade edge may drop from the doctor under the influence of gravity, and the printing plate or the object to be printed passes under the doctor. If it does, it causes defects such as print stains and stains.

Further, the surplus ink may wrap around to the back surface of the doctor even if it does not drop from the doctor blade edge. At this time, when the doctor spreads the ink while making pressure contact with the printing plate, the surplus ink is transferred to the back surface of the doctor. The adhered ink appears as doctor stripes on the printing plate, resulting in defective printing.

As described above, the ink adhering to the doctor blade tip causes deterioration of print quality.

For this reason, the operator regularly wipes off the ink adhering to the doctor blade portion after the completion of the ink supply operation to the intaglio plate by the doctor, but this method is inferior in workability and cannot repeatedly perform efficient printing. There is a problem.

There is also a problem that dust is generated during the wiping operation. Dust also becomes defective when it adheres to the printing medium, but when it adheres to the printing plate, in addition to printing defects such as streaking of the ink pattern and pattern chipping,
It has various adverse effects such as dust transfer to the blanket surface.

The present invention solves such a problem. After the ink spreading operation is completed, the ink adhering to the doctor tip portion is removed by a wiping means, whereby the ink adhering to the doctor blade tip portion is transferred to the back surface of the doctor. An ink spreading method, an ink spreading device, and a printing device capable of realizing high-precision and high-quality printing even if repeated printing is performed by suppressing the generation of doctor streaks that wrap around and ink dripping from the doctor tip It is intended to provide.

[0014]

SUMMARY OF THE INVENTION An ink spreading device of the present invention for solving this problem is a moving member that can move up and down with respect to a printing plate, a doctor fixed to the moving member, and the moving member. And a wiping member which is disposed on the member and moves in parallel in the longitudinal direction of the doctor while being in contact with the blade edge of the doctor.

[0015]

According to the present invention, the ink adhering to the doctor blade edge portion is removed by the wiping member after the ink spreading operation is completed by the wiping member, so that the ink adhering to the doctor blade tip portion wraps around to the back surface of the doctor plate. Highly accurate, even when repeated printing is performed by suppressing the generation of doctor streaks that cause ink residue on the surface and the dripping of ink from the doctor blade edge.
High quality printed matter can be supplied.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A printing apparatus using an ink spreading apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the construction of an ink spreading apparatus according to an embodiment of the present invention. In FIG. 1, 1 is a fixed mount, 2 is an elevating cylinder, 3 is an elevating member, and the elevating member 3 is capable of elevating and lowering a lower printing plate (not shown) by an elevating cylinder 2 fixed to the fixed mount 1. Has become.

Reference numeral 4 denotes a doctor for spreading the ink, which is arranged on the elevating member 3. Reference numeral 5 is a rodless cylinder, 6 is a sliding member, and the rodless cylinder 5 is fixed to the elevating member 3 such that the axial direction of the cylinder axis is parallel to the cutting edge of the doctor 4.

Reference numeral 7 is a wiping member, and 8 is an ink collecting container provided in the wiping member 7. The wiping member 7 is connected to the moving plate 6 by a connecting member 9.

Due to such a constitution, when the doctor 4 is separated from the lower printing plate (not shown),
When the wiping member 7 is driven leftward from the state shown in the drawing,
The wiping member 7 can be moved in the longitudinal direction while being in contact with the blade edge of the doctor 4.

For this reason, the ink adhering to the blade portion of the doctor 4 is removed by the wiping member 7, and the ink recovery container 8 is removed.
Can be collected in.

How to print using the ink spreading device configured as described above will be described with reference to FIG.

FIG. 2 is a block diagram showing a case where offset printing is performed using the ink spreading device shown in FIG.

In FIG. 2, 10 is a gantry, 11 is a moving shaft, 12 is a carrier, the moving shaft 11 is fixed to the gantry 10, and the carrier 12 is movable in the axial direction of the moving shaft 11. There is. A printing plate 13 is mounted on the carrier 12. An ink supply device 14 supplies ink to the pattern formation surface of the printing plate 13.

Reference numeral 15 denotes the ink spreading device shown in FIG.
A doctor for contacting the surface of the printing plate 13 with pressure and spreading the ink is arranged. A blanket 16 is a printing plate 13.
After the ink pattern image is transferred by rolling on the surface of, the ink pattern image is printed by rolling on the surface of the printing medium (not shown).

Next, in the ink spreading apparatus according to the present embodiment, how to suppress the generation of print stains and doctor stripes due to the dripping of the ink adhering to the blade edge of the doctor will be described again with reference to FIG. To do.

Excess ink other than that filled in the print pattern groove is scraped off while being spread by the doctor 4.

However, when the doctor 4 slides on the lower printing plate (not shown) while making pressure contact, excess ink collects between the doctor 4 and the printing plate (not shown), and along the blade edge of the doctor 4. It is coming up.

After the ink spreading operation is completed, the doctor 4
However, when leaving a printing plate (not shown), most of the excess ink is pulled up while adhering to the doctor 4, and an ink pool is formed at the blade edge of the doctor 4.

If left as it is, the ink adhering to the blade edge portion of the doctor 4 will fall under the influence of gravity or will wrap around the back surface of the doctor 4 to cause print stains and doctor streaks.

Therefore, after the ink spreading operation is completed, the ink attached to the blade portion of the doctor 4 is moved by the sliding member 6 along the axial direction of the cylinder axis of the rodless cylinder 5,
By moving the wiping member 7 in the longitudinal direction of the doctor 4 while keeping it in contact with the doctor 4, the ink adhering to the blade portion of the doctor 4 can be removed and collected in the ink recovery container 8.

Therefore, after the ink spreading operation is completed, the next printing operation can be started in a state where the ink is not attached to the tip portion of the doctor 4.

Therefore, a printing failure caused by the ink adhering to the doctor blade portion does not occur.

In this embodiment, the ink recovery container is installed on the wiping member, but the ink recovery container may be installed below the doctor, for example.

Further, in this embodiment, the ink collecting container is arranged on the wiping member. However, for example, the ink collecting container can be replaced by a detachable type, or the ink collecting container is provided with an ink removing portion, which is set in advance. Stable continuous printing can be performed by exchanging the ink recovery container or removing ink from the ink recovery container after each printing.

[0036]

As is apparent from the above description of the embodiments, according to the present invention, the ink adhering to the doctor blade tip portion is removed by the wiping member after the ink spreading operation is completed, and thus the ink is attached to the doctor blade tip portion. This prevents the streaks of ink on the surface of the printing plate and the dripping of the ink from the doctor blade edge, which causes the remaining ink to go around to the back surface of the doctor, and to supply high-precision, high-quality printed matter even after repeated printing. You can

Further, even when the offset printing apparatus is continuously operated, there is no problem of dust that has been generated during the conventional wiping work by the operator, so that good printing quality can be maintained.

Furthermore, by adding an ink recovery function such as an ink recovery container to the ink wiping member, the ink usage rate can be improved.

Further, since the wiping member has an integral structure with the doctor, the structure of the printing apparatus can be simplified and made compact.

As described above, the present invention has extremely high industrial value.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of an ink supply device of the invention.

2 is a configuration diagram of an offset printing apparatus using the ink supply apparatus of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixed mount 2 Lifting cylinder 3 Lifting member 4 Doctor 5 Rodless cylinder 6 Sliding member 7 Wiping member 8 Ink collection container 9 Connecting member 10 Mounting base 11 Moving shaft 12 Conveying base 13 Printing plate 14 Ink supply device 15 Ink spreading device 16 blanket

Claims (3)

[Claims] 1. An ink spreading method for removing ink adhering to the blade edge portion of the doctor after the ink is spread by a wiping means that moves in parallel with the doctor blade edge portion in the longitudinal direction of the doctor blade. 2. A moving member which can be moved up and down with respect to a printing plate, a doctor fixed to the moving member, and a parallel plate extending in the longitudinal direction of the doctor while being in contact with a cutting edge of the doctor disposed on the moving member. An ink spreading device having a moving wiping member. 3. An ink supply device for supplying ink to a carrier, which is arranged on a frame and is movable in the axial direction of a moving shaft, a printing plate mounted on the carrier, and a pattern forming surface of the printing plate. A printing device comprising: the ink spreading device according to claim 2; and a blanket that rolls on the surface of the printing plate to transfer an ink pattern image.