JPS62269144A - Automatic developing machine for photosensitive planography - Google Patents

Abstract

PURPOSE:To supply a developer stably at any time by measuring the degree of elution of the quantity of exposure of a PS plate of the largest size directly by a sensor in the middle of development or counting the version of a PS plate of smaller size. CONSTITUTION:When a small PS plate 3 is passed, an input from a sensor 5 is 0 and an input from a sensor 6 is 1, so an exclusive OR circuit 23 outputs a signal of 1 and a presettable counter 24 counts up by one. When the specific quantity of plates is reached, a pump driving circuit 25 is supplied to a developer supply instruction to drive a pump 28. A sensor 7 which detects the degree of elution of the photosensitive layer of the PS plate, on the other hand, is connected to a comparator 26, which makes a comparison with a specific level set by a reference value setting circuit 27; when the degree of elution does not reaches the specific level, the fatigue of a developer is judged and a signal for developer supply is outputted to the pump driving circuit 25.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a photosensitive lithographic printing plate (28th plate) with an auto feeder.
The present invention relates to an automatic developing machine, and more specifically, to an automatic developing machine having a function to prevent a decrease in the developing ability of a developer that occurs when processing a large number of 28 plates.

[Conventional technology and problems]

Conventionally, a 28-plate image is exposed, developed using an automatic processor, and then subjected to predetermined post-processing to produce a lithographic printing plate.Generally, when developing using an automatic processor, a large number of 28-plates are processed. When processed, the developer in the automatic processor becomes exhausted, and therefore the developer needs to be replenished or replaced. Therefore, conventionally, automatic processing machines are equipped with an automatic replenishment mechanism for developer solution or development auxiliary solution to automatically replenish them. The replenishment mechanism automatically operates accordingly. For example, Japanese Unexamined Patent Publication No. 115039/1983 describes a method of parallel replenishment corresponding to the throughput of 28 editions and replenishment corresponding to the elapsed time, but specifically, replenishment according to the throughput is automatic. A developer replenisher is replenished in an amount corresponding to the time that the 28th plate travels through the developing machine, and a predetermined amount of developer replenisher is replenished at regular intervals. However, in this method, only the length of the 28th plate in the running direction of the 28th plate is measured, so even if the width of the 28th plate or the image area that consumes developer changes, the length of the 28th plate remains constant. In this case, the same amount of developer replenisher would have to be replenished, which may not suit the actual situation. In addition, even when replenishing over time, the developer replenisher is replenished at regular intervals, so there is a problem that the optimal replenishment amount changes depending on the amount of developer stored in the automatic processor and the concentration of carbon dioxide in the air. there were. Therefore,
In the invention described in Japanese Patent Application Laid-Open No. 58-95349, there is a
A method has been proposed in which a sensor is provided that can measure the degree of elution of a non-image area of a photosensitive layer of a printing plate, and a replenishment mechanism is activated when the degree of elution detected by this sensor falls to a predetermined level.

However, in this method, the sensor measures the position of the non-image area, that is, the edge, of the moving 28th plate, so naturally the 28th plate is pushed to one side inside the automatic processor. , must pass through a sensor installed at the edge.

In other words, in this method, the 28th plate must be loaded to one side in an automatic developing machine, and plate feeding mechanisms of various sizes can only be applied to the largest size of 28th plate.

[Purpose of the invention]

The present invention solves the problem with the prior art as described above.For the largest size 28 plate, the degree of elution of the photosensitive layer of the 28 plate during development is directly measured using a sensor to determine the degree of deterioration of the developer. By using both the method of replenishing the developer replenisher using the machine and the method of counting the number of plates and replenishing it with a counter for smaller size 28 plates, stable replenishment of the developer replenisher is automatically achieved at all times. Our objective is to provide a new automatic developing machine.

[Summary of the invention]

The present invention provides a method for developing a large number of image-exposed 28 plates using an automatic developing machine for photosensitive lithographic printing plates (28 plates) equipped with an auto feeder to which a replenishing device for development auxiliary liquid is connected. By installing sensors at the edges between the development zone and autofee finish of the automatic processor, and at a part of the center, the size and size of the 28th plate can be identified, and the size and size of the 28th plate can be identified by only the sensor in the center part. The counter is replenished by counting the number of plates, and for plate 28, which is detected by both sensors at the edges and a part of the center, elution of the photosensitive layer of the non-image area of plate 28 is carried out at a position in the middle of the development zone. A sensor is provided to measure the degree of elution, and the degree of elution detected by the sensor is determined to be a predetermined value. It is a machine.

[Details of the invention]

The present invention will be explained in detail below.

First, the photosensitive printing plate (28th edition) is put on this automatic developing machine.
However, this is paper and plastic.

Paper-plastic composites, aluminum and copper.

After the surface of a plate or sheet support made of metal such as steel is modified as desired or an undercoat layer is applied, a photosensitive composition is applied to form a photosensitive layer. The formed photosensitive printing plate is image-exposed.

The photosensitive compositions to be coated on the above-mentioned support are generally of positive type and negative type, both of which are well known. A positive photosensitive composition basically consists of an O-quinonediazide compound as a photosensitive component and an organic polymer compound as a binder that hardly dissolves in weak alkaline water with a pH of less than 12 but easily dissolves in strong alkaline water. The negative-working photosensitive composition is a composition consisting of a diazo resin as a photosensitive composition and a polymer compound having an acidic group such as a carboxyl group or an alkali-soluble group as a binder. In order to improve the performance of these photosensitive compositions, for example, an indicator for forming a printout image, and dibutyl phthalate and tricresyl phosphate for imparting flexibility to the coating film of the photosensitive composition. Plasticizers, stabilizers such as phosphoric acid and phosphorous acid to suppress the decomposition properties of V azo resin over time, surfactants to improve the film strength of coatings, chelating agents to prevent staining of plate surfaces, and various other substances. Various additives can be added, such as oil-soluble dyes.

Each of these components is dissolved in an organic solvent to prepare a coating solution, which is coated on a support and dried to form a photosensitive layer.
This is the 8th edition. The coating amount for forming a photosensitive layer is determined by the dry weight (
The weight of the photosensitive layer is usually about 0.3 to about 617 m211
c equivalent amount, more preferably about 0.5 to about 3,
It is 0η blasphemy.

The 28 plates thus produced are placed on an exposure device overlapping the desired original film and exposed to ultraviolet-rich light. In this exposure, the 28th plate is exposed while being superimposed on the original film, so that the photosensitive layer is imagewise exposed after all.-7 Thereafter, the 28th plate is developed by an automatic processor.

The automatic developing machine to which the present invention is directed is as shown in FIG. 1, and is a printing plate horizontal conveyance type automatic developing machine equipped with an auto feeder 1 and a replenishing device 16 for developer replenisher.
A printing plate to be processed is fed by an auto feeder 1 with its center aligned and transported horizontally. During this process, a processing tank 4' for each processing liquid is provided, and the printing plate being transported passes through the processing tank 4'. The printing plate to be treated is subjected to the specified treatment through a process of coming into contact with each treatment solution at step 2, then being squeezed, optionally washed with water, and then coming into contact with other treatment solutions. This is a type of automatic developing machine in which a replenishment tank 1 is added to the solution to prevent exhaustion of the developer.
1 is equipped with a mechanism for automatically replenishing the developer replenisher in the developer replenisher 1 using a pump 28.

Figure 3 shows a simple principle of plate feeding using an auto feeder.

As shown in Figure 3, the compressor tank 8 and the solenoid valve 9
, the 28th plate 2.3 is sucked by the suction disk 10, lifted up and conveyed. Here, if 28
If you want to feed plates 2.3 to one side, install the suction disks in an array at appropriate intervals up to the width of the largest size 28 plates, and then feed the plates 2.3 to one side. The size of the above 28 plates must be detected by some method, and the suction disk must be controlled so that it operates only as wide as the 28 plates of that size. Due to the technical difficulties mentioned above, all current auto feeders are centered.

This type of automatic processor is of the same type as many conventionally commercially available machines, and its configuration, mechanism, etc. are well known.The features of the present invention are as follows. As a mechanism for replenishing the developer replenisher as described above, for the largest size 28 plate, the degree of elution of the photosensitive layer of the 28 plate during development is directly measured with a sensor to determine the degree of deterioration of the developer. The development supplement was replenished by the developer, and for smaller size 28 plates, the number of plates was counted and the counter was replenished.

As shown in FIG. 1, the 28 plates 2.3 fed by the auto feeder 1 are detected by a proximity switch or phototube type for detecting the passage of the PS plate installed at the side end position between the auto feeder 1 and the automatic developing machine 4. The size of P, 8th edition 2.3 is identified based on the detection signals from the sensor 5 and the sensor 6 provided at the center.

In other words, when 28 version 2.3 is detected by both sensors 5 and 6, it is the largest size 28 version 2, and when it is detected only by the center sensor 6, it is the smaller size than 28 version 2. It is determined that it is 28th edition 3. Here, the largest size 28 plate 3 uses the full width of the automatic developing machine 4 even with the centering plate feeding adopted in general auto feeders, so the edges (non-image areas) of the 28 plate 2 are automatically processed. It will pass through the edge of developing machine 4,
This is inspected by a development state detection sensor 7 which measures the degree of elution of the photosensitive layer in the non-image area of the 28th plate, which will be explained in detail later. However, since the 28 plate 3 having a size smaller than the PS plate 2 runs with the center of the automatic processor 4 as a reference, it does not pass over the sensor 7 that measures the degree of elution and is not inspected.

Therefore, when a large number of small size 28 plates 3 are continuously fed by the auto feeder 1, the developer replenisher is not replenished at all. Therefore, the inventor used the method described above to identify the largest 28 editions 2 and the smaller 28 editions 3, and calculated the number of smaller 28 editions 3 other than the largest 28 editions 2. The number of editions is counted using a preset counter using a counter circuit as shown in Figure 2.
As a sensor for measuring the degree of elution of the photosensitive layer of the 28th plate according to the present invention, which replenishes a certain amount of developer replenisher when a certain number of plates is reached, (1) the sensor measures the remaining amount of the colored photosensitive layer; , a light reflection sensor that measures the intensity of the reflected light by applying light from above and converts it into an electrical signal, or in the case of a transparent support, a light transmission sensor that measures the intensity of the transmitted light, and (2) a metal support. In this case, an AC impedance meter measures the electrical resistance of the film as the remaining amount of the photosensitive layer changes, and an AC bridge meter measures the capacitance and equivalent resistance of the film as the remaining amount of the photosensitive layer changes. be. When measuring the degree of elution of the colored photosensitive layer (1) using an optical sensor, the degree to which the photosensitive layer remains without being removed is read as a change in the output voltage of reflected or transmitted light, and a certain output voltage is reached. At this time, the replenishing device is activated to automatically replenish a certain amount of developer replenisher.

The measurement of the remaining photosensitive layer in (2) is limited to those in which the support is electrically conductive. The degree of dissolution due to development of the photosensitive layer coated on the conductive metal support is measured as the electrical resistance, capacitance, or equivalent resistance of the remaining photosensitive layer, and when the measured value reaches a certain value, a replenishing device is activated. Activate it to replenish a certain amount of developer replenisher. In this case, measurement can be performed in the developer without contacting the 28th plate.

FIG. 4 shows an explanatory diagram of an example of non-contact measurement.

One electrode plate 12 is placed on the 28 plate 11 on the side coated with the photosensitive layer with a distance of 1 to 5 QIIl in a developer 13. The other electrode 14 is placed on the same 28 plate 11 at a position where the development progresses further than the same position as the electrode plate 12, that is, at a position closer to the exit of the development zone. Place 1-5Q 1ml apart.

It is necessary that an electrolytic developer 13 exists between the 28th plate 11 and the electrode plates 12 and 14, and the electrode sensor 15 is installed at a position where the developing solution does not fatigue the photosensitive layer in the non-image area of the 28th plate 11. It is desirable to provide it at a position where it elutes approximately at . The solubility difference due to the PSS plate original light layer development state (developer fatigue level) is detected by the resistance value using the electrode plate sensor, compared with the set value obtained in advance by experiment, and replenished when the set value is exceeded. .

FIG. 2 shows a block diagram of a circuit configuration for performing the above processing.

The sensor 5 installed at the side edge position and the sensor 6 installed at the center are at high level (1) during the passage of the 28th plate.
The rising edge is detected by differentiating circuits 21 and 22 and transferred to exclusive OR circuit 23 via one-shot multivibrator 9 and 30. In the exclusive OR circuit 23, when the largest 28th version 2 passes, both inputs become 1.
Therefore, the output signal becomes O, and it is not counted by the preset counter 24, and when the small 28 plate 3 passes, the input from the sensor 5 becomes 01, and the input from the sensor 6 becomes 1, so the exclusive OR 23 becomes 1. A signal is output, and the preset counter 24 is counted up by one. In this way, the number of passing 28 plates other than the largest size can be counted, and when a predetermined number is reached, the preset counter 24 is reset and a developer replenishment command is given to the pump drive circuit 25.
In response to this command, the pump drive circuit 25 drives the pump 28 so that a predetermined amount of replenishment developer is replenished into the automatic developing machine.

On the other hand, a sensor 7 detects the degree of elution of the photosensitive layer of the 28th plate.
is connected to a comparator 26, and the comparator 26 compares it with a predetermined level set by a reference value setting circuit 27. If the degree of elution has not reached a predetermined level, it is determined that the developer is exhausted, and the pump is started. A signal for replenishing the developer is output to the circuit 25, and the developer is replenished in the same manner as described above.

It should be noted that circuit configurations other than the circuit shown in FIG. 2 can be applied as long as they can achieve the same function, and the processing may be performed by software.

The processing solution stored in an automatic processing machine is basically a developer, and now there are also systems that follow the development process with water washing and gum solution processing, and each processing solution is processed separately. is housed in an adjacent melt tank.

The developer for developing the photosensitive printing plate used in the present invention includes sodium silicate, potassium silicate, sodium hydroxide, lithium hydroxide, and the like. The developer replenisher is an aqueous solution containing at least one of the components contained in the developer. Current gI! Preferred compositions of the solution and developer replenisher are specifically disclosed in Japanese Patent Application Laid-Open No. 54-62004 and Japanese Patent Application Laid-Open No. 55-1989.
No. 22759, JP-A-56-12645, JP-A-57
5045 and Japanese Patent Laid-Open No. 57-190950, etc., can be adopted for non-invention purposes.

As described above, the 28th plate developed according to the present invention is post-processed by conventional conventional processes, and if desired, subjected to a burning process, etc., and then used as a printing plate.

〔Effect of the invention〕

As explained in detail above, the present invention provides a P
When replenishing the developer replenisher in the automatic developing machine for S plates, for the largest size 28 plates, the degree of elution of the photosensitive layer of the 28 plates during development is directly measured with a sensor to determine the degree of deterioration of the development process. If the size is smaller than 28
A sensor counts the number of plates (counter replenishment), and an auto feeder allows stable replenishment of developing replenisher for 28 plates of various sizes. .

The basic idea of the present invention is to perform empirical liquid replenishment using counter replenishment, and measure the degree of elution of the photosensitive layer of the 28th plate, which is the largest size, to measure the degree of elution down to the delicate level. It determines the degree of fatigue of the developer and minimizes fluctuations in development.

As described above, the above-mentioned replenishment can maintain a qualitatively high level of development for the 28 plates of all sizes fed by the auto feeder, and has an extremely large practical effect.

[Brief explanation of drawings]

Figures 1 (8) and (g) are a side view and a plan view of an automatic developing machine for PS plates with an auto feeder for carrying out the present invention, and Figure 2 is an automatic developing machine showing one embodiment of the present invention. 3 is a block diagram of the processing circuit of the machine, FIG. 3 is an explanatory diagram of plate feeding by an auto feeder, and FIG. 4 is an explanatory diagram of measuring the degree of elution of the photosensitive layer of the 28th plate using a non-contact sensor. 1. Auto feeder 2, 28 plates of the largest size 3. 28 plates of smaller size 4, automatic developing machine 5, printing plate passage detection sensor 6 provided at the side edge, printing plate passage detector provided at the center Output sensor 7, developing state detection sensor 8, compressor tank 9, magnetization valve 10, suction plate n, Ps plate 12, 14. Electrode plate 13, developer 15.1! the pole sensor

Claims (1)

[Claims] In an automatic developing machine for photosensitive lithographic printing plates with an auto feeder connected to a developer replenishment device, a printing plate passage device is attached to the conveyance path of the printing plate fed by the auto feeder and detects the passage of the printing plate. a detection sensor, an identification means that receives a signal from the printing plate passage detection sensor and identifies a printing plate of the largest size from a printing plate of other sizes, and a size other than the largest size based on the signal from the identification means. A counter that counts the number of passing printing plates and outputs a developer replenishment signal when the count reaches a predetermined number, and a counter that is installed in the development zone to elute the photosensitive layer in the non-image area of the largest printing plate. A development state detection sensor detects the degree of development, and a signal is received from the development state detection sensor to determine whether the degree of elution of the photosensitive layer in the non-image area of the printing plate has reached a predetermined level. determination means for outputting a developer replenishment signal; and a drive circuit that drives the replenishment device to replenish a predetermined amount of developer when receiving a developer replenishment signal from the counter or a developer replenishment signal from the determination means. An automatic developing machine for photosensitive planographic printing, characterized by comprising: