JPH0640577A - Form plate feeding method with multiple plate feeding prevention mechanism - Google Patents

Abstract

PURPOSE:To prevent multiple form plate feeding, dislocation from a specified position, etc., by providing a transport means with form plate sucking means, air injection means provided at a position opposed to the side of the form plates, and a means to position at least a part of the stacked pre-treatment form plates in stacking direction. CONSTITUTION:Sucking pads 104 to 109 mounted on a transport arm 103 lower to form plates stacked on a form plate pallet 102, and make in contact with the surface of the uppermost form plate 101 for sucking. Then compressed air is injected from an air infection nozzle 110 to the side of the form plates 100, and a clearance is provided between these stacked form plates to inject air. In this case, the position of the form plate 102 is restricted by a positioning pin 202B and a pressing material 203B. The uppermost form plate 101 sucked by the sucking pad 104 is raised according to rise of the sucking pad 104. Thus the form plate can be fed out also to the next process while maintaining an accurate position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing plate feeding method provided with a plate feeding prevention mechanism for a plurality of sheets in a plate making apparatus for lithographic printing plates.
In particular, the present invention relates to a printing plate feeding method including a plate feeding prevention mechanism for a plurality of plates in an electrophotographic planographic printing plate making apparatus having side surfaces coated with an insulating resin.

[0002]

2. Description of the Related Art Many methods for producing a lithographic printing plate are already known. For example, a printing original plate is brought into close contact with an original made of a silver salt film, and the photosensitive layer of the original plate is directly exposed to ultraviolet rays or the like,
This is a plate making method in which a cured portion corresponding to the image portion of the original and a non-cured portion corresponding to the non-image portion are formed, the non-cured portion is washed and removed with alkali or water, and the cured portion is made ink-receptive. . The printing plate produced by this method is called P
It is called S version and is widely used.

On the other hand, due to advances in computer image processing technology, memory development of large-capacity data, and data communication technology, etc., in recent years, a computer is consistently operated from original input, correction, editing, layout to page setting, and a high-speed communication network. An electronic editing system that can output to an end plotter at a remote place by satellite communication is being put to practical use. In particular, in the field of newspaper printing where immediacy is required, not only electronic editing systems but also plate making systems that can directly obtain a printing plate from the data are being put to practical use. Currently, in such a plate-making system, a system using an electrophotographic process and exposing with a laser light source (semiconductor laser, He-Ne laser, etc.) is being studied from various aspects.

In such a system, an elution type electrophotographic lithographic printing plate as described below can be used advantageously because it can be printed under the same printing conditions as the PS plate used conventionally. it can. As the main plate making process, the printing plate is charged, exposed, and developed, an image is formed with toner, the non-image portion where the toner does not adhere is removed with an eluent, and the surface of the support that has been previously hydrophilized Exposed to make a printing plate. Here, since the image portion protected by the toner is lipophilic, offset printing can be performed.

The electrophotographic lithographic printing plate is prepared from an electrophotographic photoreceptor in which a photoconductive layer containing a photoconductive substance is coated on a conductive support such as aluminum. Examples of the material forming the photoconductive layer of this electrophotographic photoreceptor include JP-B-37-17162, 38-758 and 46-3.
9405, JP-A Nos. 52-2437 and 57-161.
863, 58-2854, 58-28760
No. 58-118658, No. 59-12452,
59-49555, 62-217256, 6
Organic photoconductive compound / binder resin materials such as those described in JP-A-3-226668 and JP-A-1-261569 are excellent in practical sensitivity and printing durability.

In the plate making process of the electrophotographic lithographic printing plate,
On the photoconductive layer of the electrophotographic photosensitive member, a predetermined charging process is first performed to apply a uniform charge. The exposure then forms an electrostatic latent image corresponding to the image. Then development and fixing process using electrophotographic developer is performed,
A toner image corresponding to the electrostatic latent image is formed. The non-image areas other than the toner image are dissolved and removed (eluted) by an eluent containing an alkaline agent, etc., followed by washing with water or adjusting the apparent pH of the plate surface with an acidic rinse,
If necessary, a plate surface protective solution (protective gum solution) may be applied to obtain a final printing plate.

By the way, when a toner image is obtained by so-called reversal development in the above-mentioned developing process, a good image without fog and line thinning can be obtained due to its excellent developing characteristics. Recently, particularly high resolution and high quality image reproducibility are required, and a method for producing an electrophotographic lithographic printing plate by reversal development is a method that meets this quality requirement.

When reversal development is performed, first, in the exposure step, light is irradiated to a portion to which toner is to be attached, that is, an image area, and the potential of the light irradiated portion is attenuated to almost 0V. To be At this time, the portion where light irradiation is not performed, that is, the portion corresponding to the non-image portion, maintains the initial charging potential as it is. In the developing process area, a predetermined developing bias is applied between the electrode filled with the liquid developer and the electrophotographic lithographic printing plate via the electrode. In this case, as the toner particles in the developer, those having the same polarity as the electrophotographic planographic printing plate side charged by a predetermined method are used. In such a state, when the photoconductor having an electrostatic latent image is carried into the developing electric field in the developing process area, the toner particles in the developer are migrated to the photoconductor side by the developing electric field, which is a light irradiation portion. Toner particles are attached to the 0V portion of the photoconductor. At this time, the portion corresponding to the non-image area where the initial charging potential remains repels the toner particles, and the adhesion of the toner particles is avoided.

As a developer used for such reversal development, either a dry developer or a liquid developer can be generally adopted, but when a liquid developer is used, the toner particles are made fine. Therefore, high resolution and good image reproducibility can be obtained. The liquid developer is
A pigment (dye) or polymer particles are dispersed in a highly insulating medium, colored as necessary, and a charge control agent is added to this to impart a predetermined charge.

Further, in reversal development, printing stains may occur on the side surface of the printing plate due to toner adhesion during development, and in order to prevent this, an insulating resin or the like is previously formed on the side surface of the plate before plate making. It is known to apply (Japanese Patent Application Laid-Open No. 63-178240 and Japanese Patent Application Laid-Open No. 4-22972).
No.

[0011]

By the way, image data from a PS plate automatic plate making apparatus or a computer is
In an apparatus for directly making a printing plate including an electrophotographic reversal development process using a laser light source, a printing plate before the plate making is preliminarily stacked at a predetermined position on a dedicated table in a predetermined position in the apparatus. Mounting. Next, from this state, the plate feeding process of automatically supplying the plate to the exposing (or charging and exposing) process for each sheet is automatically performed. In such an apparatus, it is general that no interleaving paper or the like is inserted between each of the multiple printing plates before printing, which are stacked. As such a device, for example, "Newspaper Technology", No. 133 P16-23 (19
The computer direct plate making apparatus described in 90) and the like can be mentioned.

In the stacked printing plates before plate making in the apparatus as described above, the gap between the printing plates is exhausted by the air between the plates due to the weight of the plates to bring them into close contact with each other. It often happens that the above printing plates are closely fed to each other. In particular, a printing plate coated with a resin or the like on the side surface for the purpose of preventing printing stains on the side surface of the printing plate often has a high frequency of feeding a plurality of plates due to the resin on the side surface. If such a multi-plate feeding occurs, it causes a problem such as a conveyance jam in a subsequent process, which is extremely inconvenient.

Further, in order to avoid the occurrence of the above problems, various mechanisms have been devised for the purpose of preventing so-called two-sheet feeding. For example, there are those in which a brush is installed so as to be in contact with the side surfaces of the loaded printing plates, and those in which air is blown from the periphery of the side surfaces of the printing plates. However, these are not sufficient in their effect, and the position of the uppermost printing plate of the stacked printing plates is fixed by suction means or the like, but the printing plate at the lower part is There is a possibility that it will move from a predetermined position due to force. In that case, there have been inconveniences such as damage to the surface of the printing plate and the applied side surface, and deviation from a predetermined position determined on a dedicated table.

[0014]

The above-mentioned problems can be solved by the present invention having the following constitution. That is, the present invention, in a step of supplying at least the sheet-shaped lithographic printing plate having a metal support to the next step of the apparatus for plate making by performing exposure processing and development treatment, At least a conveying means (A) provided with the printing plate adsorbing means that can move up and down with respect to the stacked printing plates before processing, and an air ejecting means that is installed so as to face the side surface of the printing plate. (B), means for aligning at least a part of the stacked printing plates before processing in the stacking direction, and after adsorbing the printing plates by the adsorbing means, by means (B) While ejecting air to the side surface of the printing plate, the means (A) performs at least one or more vertical movements, and further aligns at least part of the printing plates stacked by the means (C) in the stacking direction. is there.

Further, a second invention according to the present invention is an electrophotographic lithographic printing plate wherein the lithographic printing plate is coated with a photoconductive layer,
Further, the electrophotographic liquid reversal development process is performed in the lithographic printing plate making apparatus according to the first invention.

Furthermore, a third invention according to the present invention has a constitution in which at least an insulating resin is applied to the side surface of the electrophotographic lithographic printing plate. The insulating resin used in the present invention is a polymer that holds a positive or negative charge by a charging means such as corona discharge, and the material thereof is not limited, and may be fluorine-based or silicone-based.

[0017]

Embodiments of the present invention will be described in detail below with reference to the drawings. 1, FIG. 2, and FIG. 3 schematically show a configuration example of a plate feeding section according to the present invention in a drawing plate making apparatus. In FIG. 2, reference numeral 101 denotes the printing plate located at the top of the stacked printing plates. First, the positioning pin 202 moves to a predetermined position (state from 202A to 202B), and then the pressing material 203 moves to a predetermined position to press the printing plate 101 (state from 203A to 203B). It is preferable that the distance between the positioning pin 202B in the pushed-in state and the pressing member 203B is set to be slightly larger than the size of the printing plate 101. This distance is 1m
The mechanism may be arbitrarily set within m, or may be a mechanism having tolerance in the moving direction of the pressing member 203 so that the pressing force does not exceed a certain force.

Next, referring to FIG. 1, the printing plate pallet 10 is used.
With respect to the printing plates 100 that are stacked on top of each other, the suction pads 104 to 109, which are attached to the transport arm 103 and are present as a pair on the same axis, descend (104A to 104A).
From the position of 109A to the positions of 104B to 109B) The surface of the printing plate 101 which is the uppermost plate is contacted, suction is started, and suction is performed. Then, compressed air is jetted from the air jet 110 to the side surface of the printing plate 100. This creates a gap between each of the stacked printing plates and allows air to be inserted. Next, the suction pad 104 closest to the side surface of the printing plate 100 on which the compressed air is sprayed is repeatedly moved up (position 104A) and lowered (position 104B) several times, and finally the suction pad 104 moves up. Stop at position (position 104A). The position of the suction pad 104 is the printing plate 10.
It is desirable to be as close as possible to the side surface of 0, and the distance between the suction pads 104 and 105 is larger than the distance between other suction pads, for example, the distance between the suction pads 108 and 109. Print version 10
This is preferable because it can reduce the stress on 0. Also,
For the suction pad, the printing plate has a physical adverse effect, and in the electrophotographic planographic printing plate, the elasticity of the pad itself is necessary in order not to adversely affect the charging performance. It is desirable to have a mechanism (eg ball joint, spring, etc.).
An air cylinder is preferably used as the means for moving the suction pad 104 up and down. Further, the number of suction pads can be arbitrarily changed according to the area and weight of the printing plate and the suction capacity of the suction pads. Similarly, the number of the air jetting ports 110 can be changed depending on the area and weight of the printing plate and the air jetting ability, but a plurality of the air jetting holes 110 are preferably installed for uniform jetting.

The above operation will be further described with reference to FIG.
The uppermost printing plate 101 sucked by the suction pad 104 is lifted as the suction pad 104 moves up. As a result, air is inserted between the printing plate 101 and the printing plate 102 located therebelow. In addition, the printing plates 102 located above the printing plates 100 also come into contact with each other by the force of the compressed air jetted as shown in the drawing from the state where they are in close contact with each other. At this time, the position of the printing plate 102 is regulated by the positioning pin 202B and the pressing member 203B as shown in FIG.
Positional movement due to the force of compressed air does not occur. As a result, the printing plates subsequent to the printing plate 101 after the printing plate 101 are conveyed are also set at the proper positions, and the printing plates can be sent to the next step while maintaining the correct position.

Next, the suction pads 105 to 1 in FIG.
09 rises in sequence (from 105A-109A position 1
05B to 109B position), and finally raise all suction pads while inserting air between the printing plates (104B to 109B).
Position) ends. After that, the plate feeding arm 103 rises to move to the charging process or the exposure (drawing) process.
1 is conveyed.

The above-mentioned positioning pin 202 and push member 2
The position 03 alignment operation depends on the stroke between each AB, but the movement of the printing plate beyond this can be restricted at the A position, so that the printing plate at the uppermost position is fully sucked from other printing plates. The operation may be performed at a time when the pads are lifted and separated.

According to the present invention, plural plates are prevented from being fed in the plate feeding process in the planographic printing plate making apparatus, and troubles such as jams in the subsequent process can be avoided, and at the same time, from a predetermined position of the printing plate. Can also be prevented. In particular, even when an electrophotographic planographic printing plate having a side surface coated with a resin or the like is used, it is possible to prevent plural plates from being fed and deviation from a predetermined position.

[Brief description of drawings]

FIG. 1 is a schematic side view of a plate feeding section of a plate making apparatus according to the present invention.

FIG. 2 is a schematic partial plan view of a plate feeding section of the plate making apparatus according to the present invention.

FIG. 3 is a partially enlarged schematic view of a plate feeding section of the plate making apparatus according to the present invention.

[Explanation of symbols]

 100 printing plate (stacked state) 102 printing plate pallet 103 plate feeding arm 104A, B plate feeding pad 105A, B plate feeding pad 106A, B plate feeding pad 107A, B plate feeding pad 108A, B plate feeding pad 109A, B feeding Plate pad 110 Air jet 101 Printing plate located at the top 110 Air jet 201 Printing plate 202A, B Positioning pins 203A, B Pressing material 100 Printing plate (stacked state) 101 Printing plate 102 located at the top 102 Printing plate ( Air insertion state) 104 Plate feeding pad

Claims (3)

[Claims] 1. A step of supplying a stacked pre-processed printing plate to a subsequent step in an apparatus for plate-making by performing at least exposure and development processing of a sheet-shaped planographic printing plate having a metal support. At least a conveying means (A) provided with the printing plate adsorbing means that can move up and down with respect to the stacked printing plates before processing, and an air jet installed opposite to the side surface of the printing plate. Means (B), means (C) for aligning at least a part of the stacked printing plates before processing, in the stacking direction, and the means (B) after adsorbing the printing plates by the adsorbing means While ejecting air to the side surface of the printing plate by means of the means (A), the means (A) performs at least one vertical movement, and at least a part of the stacking direction of the printing plates stacked by means (C) is aligned. Multiple plate supply featuring A printing plate feeding method with a prevention mechanism. 2. The lithographic printing plate is an electrophotographic lithographic printing plate coated with a photoconductive layer, and an electrophotographic liquid reversal development process is performed in a plate making apparatus for the lithographic printing plate. A printing plate feeding method with a multi-plate feeding prevention mechanism. 3. A printing plate feeding method having a multi-plate feeding prevention mechanism according to claim 2, wherein at least an insulating resin is applied to a side surface of the electrophotographic planographic printing plate.