JPH08240916A - Developing device for waterless planographic printing plate - Google Patents

Abstract

PURPOSE: To easily and accurately develop a printing plate at a high speed by providing the developing device with brush rolls which rotate in the same direction as the carrying direction of a printing plate and with brush rolls which rotate in the opposite direction to the carrying direction. CONSTITUTION: A printing master plate 1 is rubbed with brush rolls 8, 9 so that a silicone rubber layer in the image part is removed. These brush rolls are disposed to be uniformly in contact with the plate and to rotate in the opposite direction to each other, and are movable along the axial direction. The brush rolls 8, 9 are constituted of at least one roll which rotates in the same direction as the carrying direction of the printing master plate 1, and at least one roll which rotates in the opposite direction. The first brush roll is rotated in the same direction to the carrying direction, while the second and succeeding rolls are rotated in the opposite direction. At least one of the rolls 8, 9 is oscillated, thereby uniform dots without directionality can surely be obtd. and rapid development is made possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for a waterless lithographic printing plate, and more particularly to an improvement in a developing device for a waterless lithographic printing plate having a silicone rubber layer backed by a substrate as an uppermost layer.

[0002]

2. Description of the Related Art Waterless lithographic printing plates having a silicone rubber layer lined on a substrate as an uppermost layer are disclosed, for example, in JP-B-46-16044, JP-A-50-50102, and JP-A-55-59466. It is proposed in the Gazette and the like.

These waterless planographic printing plates are subjected to image exposure processing by a known method and developed. When developing is carried out using an automatic developing machine, a plate-shaped printing original plate is conveyed by rolls. A developing device is used in which the brush roll is rotated so that the printing original plate is rubbed in the same direction as the advancing direction at the contact portion of the one to four brush rolls, and the silicone rubber layer in the image area is removed. It is common.

As described above, the reason why the brush roll is used for developing the waterless planographic printing plate is that the silicone rubber layer on the surface is generally insoluble and therefore needs to be rubbed by a mechanical force. In addition, it is the most practical means to meet this purpose. Further, the reason why the brush roll is rotated so as to rub it in the same direction as the traveling direction of the printing original plate is to prevent the tip of the printing original plate from being splashed by the brush roll.

[0005]

In the case of such a developing device, there arises a problem that the shape of the developed halftone dot depends on the rubbing direction of the brush roll and a halftone dot having a uniform shape cannot be obtained. Often.

That is, in the halftone dot, the silicone rubber layer is almost completely removed on the downstream side in the rubbing direction of the brush roll, whereas the silicone rubber layer tends to remain on the upstream side, especially at the edge of the halftone dot. Is. As a result, the tone reproducibility is deteriorated even during printing, and a color defect occurs, which causes serious defects.

Therefore, an apparatus described in Japanese Patent Laid-Open No. 60-59351 has been proposed as an apparatus for improving the drawback.

This apparatus uses two or more brush rolls when rubbing and developing the printing original plate, and at least one of the brush rolls is rubbed by rotating in the opposite direction to the other brush rolls. The silicone rubber layer at the edge of the halftone dot is removed.

However, in the case of this apparatus, if the brush roll which is rotated in the direction opposite to the conveying direction of the printing original plate is made to have a strong rubbing force, the printing original plate is repelled, so that the rubbing force of the brush roll must be weakened. ,
As a result, especially for thick printing plates with a silicone rubber layer,
There is a problem that the silicone rubber layer at the edge of the halftone dot is not uniformly removed and remains. Further, there are problems that the defective dot shape due to the non-uniformity of the brush material cannot be eliminated and that the silicone rubber layer is not uniformly removed and remains even by high-speed development.

[0010]

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks of the prior art, the present invention aims to provide a novel apparatus for developing a waterless planographic printing plate simply, reliably and at high speed. is there. That is, the present invention provides a waterless planographic printing plate in which a waterless planographic printing plate having a silicone rubber layer backed by a substrate as an uppermost layer is conveyed while rubbing the silicone rubber layer with at least two brush rolls for development. In the developing device, the waterless planographic printing plate is provided with at least one brush roll rotating in the same direction as the carrying direction and at least one brush roll rotating in the opposite direction to the carrying direction in the carrying direction. The first brush roll in the direction is rotated in the same direction as the conveying direction, and at least one bra seal of the at least two brush rolls is reciprocated in the roll axial direction to remove the silicone rubber layer in the image area. A developing device for a waterless planographic printing plate characterized by being physically removed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a diagram schematically showing an embodiment of a developing device for a waterless planographic printing plate according to the present invention.

The waterless lithographic printing plate used in the present invention has a silicone rubber layer backed by a substrate as an uppermost layer, and a substrate, a photosensitive layer and a silicone rubber layer laminated in this order, a substrate, Examples thereof include a laminate of photosensitized silicone rubber layers in this order, and a cover film may be provided on the silicone rubber layer.

The substrate has a thickness of about 10 microns to 2
mm, preferably about 50 to 500 microns of paper, plastic film or sheet, elastic sheet such as rubber, metal plate such as aluminum, or laminated composite material of paper and plastic film, metal plate and rubber sheet, and the like. A material obtained by subjecting these to a surface treatment such as plating or coating is used.

The photosensitive layer is a layer having a property of being photocured or solubilized by being irradiated with an active ray. This layer is evenly applied to the substrate, and its thickness is optional as long as it is in intimate contact with the substrate, but preferably about 100.
Submicron or less, and more preferably about 1 to 10 microns are more useful. If necessary, it is also useful to provide an anchor coat between the substrate and the photosensitive layer to improve adhesion between the photosensitive layer and the substrate or to prevent halation. As the photosensitive substance, a known substance such as a composition containing a photopolymerizable monomer or oligomer, a photocurable diazo compound or an azide compound, a compound containing a quinonediazide group and the like can be used.

The silicone rubber layer has a thickness of 0.5.
~ 100 microns, preferably about 1-10 microns,
A known silicone rubber known as room temperature curable type or low temperature curable type is suitable. These silicone rubbers contain a linear organic polysiloxane as a main component, and a crosslinking agent, a catalyst and the like are generally added. The silicone rubber layer in the present invention may have photosensitivity and can be obtained by chemically reacting or mixing an organic polysiloxane compound with a known photosensitizing compound. .

The brush roll used in the present invention is generally one in which a brush material such as a plastic thread or animal hair having a diameter of 20 to 500 microns is radially implanted in the core of plastic or metal, but A brush material embedded in a base material such as a sheet, a film, or a cloth may be wound around a core, and further, one in which the brush material is implanted in a plastic or metal groove material is attached to the core. Either may be used.

A developing device according to the present invention for a printing plate comprising the above components will be described in detail with reference to the drawings.

FIG. 1 is a schematic view showing an example of an automatic developing machine using the developing device according to the present invention. In the figure, the printing original plate 1 that has been subjected to the image exposure process is inserted into the developing device main body 3 from the carry-in table 2, is subjected to the developing process, and is discharged to the carry-out table 4. The developing solution sent by the pump 6 is sprayed from the spray nozzle 7 onto the printing original plate in the developing machine. The developer swells the silicone rubber layer, or weakens the adhesive force between the silicone rubber layer in the image area and the lower layer, thereby facilitating the removal of the silicone rubber layer in the image area and at the same time removing the removed silicone rubber. Generally, it has a function of washing off rubber pieces from the printing original plate. Next, the printing original plate is rubbed by brush rolls 8 and 9 which are arranged so as to be in uniform contact therewith and which rotate in mutually opposite directions and are swingable in the axial direction, respectively. Is excluded. Reference numeral 10 denotes a printing plate precursor support mechanism provided at a position facing the brush roll so that the printing plate does not escape from the brush roll. The support mechanism 10 may be a cylindrical object, but a plate-like object as shown in the figure is used. As the automatic developing machine, not only the above-mentioned basic mechanism but also a pre-processing machine, a post-processing machine, a water washing machine, a drying machine, etc. may be used, and a brush roll is also dispersedly arranged in the pre-processing machine, the post-processing machine or the water washing machine. May be. The brush roll used in the present invention requires at least one that rotates in the same direction as the transport direction of the printing original plate and at least one that rotates in the opposite direction, but the first brush roll is the transport direction. Rotate it in the same direction as
Rotate the brush roll after the th in the opposite direction. Moreover, it is necessary to rock at least one of these brush rolls. More preferably, both of the brush rolls 8 and 9 should be oscillated.

If the function of the brush roll is divided into the function of roughly removing the silicone rubber layer at the halftone dot portion and the function of finish-removing the slightly remaining silicone rubber layer at the halftone dot edge portion, the former function is It is better to rotate the brush roll made of a stiff brush material quickly, but if this is rotated in the direction opposite to the conveying direction of the printing original plate, there is a risk that the leading edge of the printing original plate will rise. On the other hand, the latter function is satisfied by slowly rotating a brush roll made of a brush material having a weak stiffness, so that the above-mentioned risk can be reduced to a level where there is practically no problem. Therefore, as the first brush roll, for example, an outer diameter of 100 to 200 obtained by implanting nylon 6/10 having a single yarn diameter of 200 to 400 microns in a bristle length of 10 to 20 mm is used.
Using a brush roll of mm, the silicone rubber layer is roughly removed by rotating it at a speed of 200 to 500 rpm for rubbing in the same direction as the direction of conveyance of the printing original plate, and slightly at the halftone dot edge portion. The brush that finishes and removes the remaining silicone rubber layer is, for example, nylon 6.10.
~ 250 micron single yarn diameter 15 ~ 30m
It is effective to use a brush roll having an outer diameter of 50 to 100 mm planted in m and rotate this at a speed of 50 to 500 rpm for rubbing in the direction opposite to the conveying direction of the printing original plate.

The swinging of the brush roll causes the brush roll to reciprocate 50 to 400 times per minute with a swinging width of 5 to 100 mm in the direction perpendicular to the transport direction of the printing original plate, that is, in the roll axial direction. As a method of rocking, a method of using a cam, a link, a shaft or the like for rocking an ink applying roller of a printing machine, or cutting a screw groove inside the roll is generally used. The specifications, rotation, and rocking conditions of the brush roll are determined by the ease of peeling the silicone rubber layer, the ease of scratching the silicone rubber layer, and the rigidity of the printing original plate, and are not limited to the above use examples. Not something.

[0022]

EXAMPLES Next, the present invention will be described more specifically by way of examples.

Example 1 Commercial positive type Toray waterless planographic printing original plate (length 1030 m
m, width 980 mm) was subjected to a halftone dot exposure treatment by a known method, the polyester film was peeled off, and then development was carried out at a conveying speed of 40 cm / min using an automatic developing machine having two brush rolls. The developer used was one containing an aliphatic saturated hydrocarbon solvent as a main component, and a dye, a surfactant, etc. added thereto. Brush roll is nylon 6
10 made, 200 micron diameter single yarn 15 mm long
1160mm long, 130m outside diameter
The first brush roll having a thickness of m is rotated 300 times per minute in the same direction as the conveying direction of the printing original plate in the rubbing direction, and the swing width is 30 reciprocations per minute.
It was rocked by mm. The second brush roll is made of nylon 6/10, and a single yarn with a diameter of 160 microns is planted so that the bristle length is 26 mm, and the length is 1160 m.
m and an outer diameter of 100 mm were rotated 180 minutes per minute in the direction opposite to the conveying direction of the printing original plate and in the direction of rubbing. As a result, it was possible to obtain a uniform halftone dot in which the silicone rubber layer at the edge portion was also removed, and it was possible to obtain a high-quality printed matter at the time of printing.

Example 2 In Example 1, the second brush roll was changed to 120 minutes per minute.
It swings back and forth with a swing width of 30 mm to achieve even higher speeds of 60 mm.
Development was carried out at a conveying speed of cm / min. As a result, it was possible to obtain a uniform halftone dot in which the silicone rubber layer at the edge portion was also removed, and it was possible to obtain a high-quality printed matter at the time of printing.

Comparative Example 1 The same waterless lithographic printing plate precursor as in Example 1 was exposed by the same method, and developed using the same developing solution and the same automatic developing machine at the same conveying speed as in Example 1. . On this occasion,
A brush roll having the same shape as that in Example 1 was used at the same rotation speed, but the brush roll was rotated in the same direction as the traveling direction of the two printing original plates, and was not rocked. As a result, only halftone dots in which the silicone rubber layer remained on the upstream side edge in the rubbing direction by the brush roll were obtained. High-quality printed matter could not be obtained even during printing, and in addition, when dust adhering to the printing plate was wiped off with a cloth during printing, the silicone rubber layer left on the edges at the halftone dots was also removed at the same time. Then, in the subsequent printing, only a printed material having a different color tone was obtained in that portion.

Comparative Example 2 The same waterless lithographic printing plate precursor as in Example 1 was exposed by the same method, and the same developing solution and the same automatic developing machine were used.
Development processing was performed at a transport speed of 0 cm / min. The first brush roll was rotated in the same direction as the traveling direction of the printing original plate, and the second brush roll was rotated in the opposite direction, but it was not rocked. At this time, the brush roll having the same shape as in Example 1 was used at the same rotation speed.

As a result, only the non-uniform halftone dots of the remaining portion of the silicone rubber layer can be obtained at the upstream side edge in the rubbing direction by the first brush roll at the part where the second brush roll hits well and the part where it does not. Remained in the shape. Even in printing, streaky patterns became apparent and high quality printed matter could not be obtained,
In addition, when dust on the printing plate was wiped off with a cloth during printing, the silicone rubber layer remaining on the edges of the halftone dots at that part was also removed at the same time. Only printed matter was obtained.

Example 3 The same waterless lithographic printing plate precursor as in Example 1 was exposed to light by the same method, and this was composed of three parts: a preprocessor, a developing machine and a postprocessing machine. The development processing was performed using an automatic developing machine having one brush roll each. That is, a pretreatment device for spraying polypropylene glycol on the printing original plate, then while spraying water on the printing original plate,
The same brush roll as the first brush roll in Example 1 is rotated 300 times per minute in the same direction as the direction of travel of the printing original plate, and is oscillated with a swing width of 30 mm at 120 reciprocations per minute and rubbed. Example 1 while spraying a developing machine and finally an aqueous solution of a dye and a surfactant on the printing original plate.
An automatic developing machine comprising a post-processing machine which rubs the same brush roll as the second brush roll in No. 1 at a speed of 180 revolutions per minute in the direction opposite to the traveling direction of the printing original plate was used. The transport speed was 40 cm / min. As a result, uniform halftone dots were obtained without bouncing the printing plate and leaving no silicone rubber layer at the edges. High-quality printed matter was obtained during printing.

Example 4 In Example 3, the brush roll of the post-processing machine was changed to 120 per minute.
It swings back and forth with a swing width of 30 mm to achieve even higher speeds of 60 mm.
Development was carried out at a conveying speed of cm / min. As a result, it was possible to obtain a uniform halftone dot in which the silicone rubber layer at the edge portion was also removed, and it was possible to obtain a high-quality printed matter at the time of printing.

Example 5 The same waterless lithographic printing plate precursor as in Example 1 was exposed by the same method, and this was composed of four parts of a pre-processing machine, a developing machine and a post-processing machine, and a washing machine. Aftertreatment machine,
Using an automatic developing machine having one brush roll for each washing machine, development processing was carried out at a conveying speed of 80 cm / min. That is, a pretreatment machine for spraying polypropylene glycol onto the printing original plate, and then water on the printing original plate, while carrying out Example 1
In the same brush roll as the first brush roll in the above, 300 revolutions per minute in the same direction as the traveling direction of the printing original plate, and a swing width of 30 mm is performed at 120 reciprocations per minute,
While rubbing an aqueous solution of a developing machine, a dye, a surfactant, and the like on the printing original plate, the same brush roll as the second brush roll in Example 1 was used to scrub the printing original plate in the same direction as the traveling direction of the printing original plate at 180 rpm. A post-processing machine for rotating and rubbing it, and finally a second brush roll in Example 1 while spraying water on the printing original plate to remove dyes and surfactants attached to parts other than the image area of the printing original plate. 180 minutes per minute in the direction opposite to the direction of the original printing plate with the same brush roll
An automatic developing machine consisting of a water washing machine was used which was rotated and oscillated at a reciprocating width of 30 mm at 120 reciprocations per minute. As a result, uniform halftone dots were obtained without bouncing the printing plate and leaving no silicone rubber layer at the edges. High-quality printed matter was obtained during printing.

Example 6 A commercially available negative-working Toray waterless lithographic printing plate precursor was subjected to exposure treatment in the same manner as in Example 1, and this was treated with the chemical solution in the pretreatment unit using the same automatic processor as in Example 5. Development was performed under the same conditions as in Example 5 except that the chemical solution containing diethylene glycol as the main component was changed. As a result, uniform halftone dots were obtained without bouncing the printing plate and leaving no silicone rubber layer at the edges. High-quality printed matter was obtained during printing.

[0032]

According to the present invention, in developing a waterless lithographic printing plate precursor, a uniform halftone dot having no directivity can be reliably obtained, and an automatic developing machine capable of high-speed development can be obtained.
As a result, the printed matter can maintain a stable ink density during printing, and a high-quality printed matter excellent in tone reproducibility can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of an automatic developing machine according to the present invention.

[Explanation of symbols]

 1: Printing original plate 2: Carry-in table 3: Developing machine main body 4: Carrying-out table 5: Roll 6: Pump 7: Spray nozzle 8, 9: Brush roll 10: Support mechanism

Claims (6)

[Claims] 1. A waterless planographic printing plate which is developed by rubbing the silicone rubber layer with at least two brush rolls while conveying the waterless planographic printing plate having a silicone rubber layer backed by a substrate as an uppermost layer. In the developing device, at least one brush roll rotating in the same direction as the conveying direction and at least one brush roll rotating in the opposite direction to the conveying direction are provided in the conveying direction of the waterless planographic printing plate. The first brush roll in the above is rotated in the same direction as the conveying direction, and at least one bra seal of the at least two brush rolls is reciprocated in the roll axial direction to physically move the silicone rubber layer in the image area. A waterless planographic printing plate developing device characterized in that it is removed selectively. 2. The developing device for a waterless planographic printing plate according to claim 1, further comprising means for reciprocating a first brush roll in a roll axis direction. 3. The waterless lithographic printing plate developing apparatus according to claim 1, wherein a cam is used for the reciprocating mechanism of the brush roll. apparatus. 4. The waterless planographic printing plate developing apparatus according to claim 1, wherein the width of the reciprocating motion of the brush roll is in the range of 5 to 100 mm. Lithographic printing plate developing device. 5. The developing device for a waterless lithographic printing plate according to claim 1, wherein the reciprocating speed of the brush roll is in the range of 50 to 400 times / minute. Waterless lithographic printing plate developing device. 6. The developing device for a waterless planographic printing plate according to claim 1, wherein a support mechanism for preventing escape of the waterless planographic printing plate is provided at a position facing the brush roll. A waterless planographic printing plate developing device characterized by being provided.