JPH07304151A - Circulation and supply device of dampening water for lithographic printing - Google Patents

Abstract

PURPOSE:To supply a dampening water for stabilized lithographic printing and ink roll circulation water which are not rotten even if they are kept or used for a long period, by a method wherein an ozone sterilizer is provided. CONSTITUTION:Dampening water in a dampening water tank 1 repeats a cycle wherein it is sucked up by a suction pump 12, sent to a water tank 4 through piping 5 and returned again to the dampening water tank 1 by passing through return piping 2. Since the dampening water is changed in quality by being influenced by evaporation of water during printing or eluted component of ink or paper, a pH control device or an electric conductivity control device 6 or an IPA concentration control device 7 are provided to control a condition of the dampening water. A water supply part 8, an IPA supply part 9 and dampening water additive agent supply part 10 are provided when need arises. An ozone generating and supply device 14 and ozone concentration control device 13 are provided further.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dampening water or ink roll circulating water circulating supply device used in lithographic printing.

[0002]

2. Description of the Related Art Lithographic printing is a printing method in which printing is performed by using a printing plate in which a portion corresponding to an image area is an oil-sensitive surface and a portion corresponding to a non-image area is a hydrophilic surface. That is, the ink is attached to the oil-sensitive surface, the dampening water is attached to the hydrophilic surface, and the mutual repulsion between the ink and the dampening water is used for printing. At this time, it is important to supply ink and dampening water to the plate surface in a proper balance. In addition to technological development for ink and dampening water, technological development on the printing machine side has progressed, and various ink roll arrangements have been made. Also, a dampening water supply mechanism has been proposed. In recent years, offset (lithographic) printing method that does not require dampening water has been put into practical use, and the printing machine has been improved accordingly. For example, constant temperature water is circulated in the shaft of the ink kneading roll to improve the printing machine. The ink temperature is controlled to deal with various problems such as stains, and the printability and printing effect are stabilized. These technologies are also used in offset printing methods that use ordinary fountain solution,
Recently, water is also passed through the pottery roll, aiming at further stable printing. In any case, it is important to print the ink stably on the material to be printed, typified by paper.In addition to technical development of the ink itself, usually lithographic printing is achieved in balance with dampening water. If too much dampening water is applied, the emulsification of the ink will become severe and transfer failure will occur.On the other hand, if too little dampening water is present, the ink will stick to the non-image areas and cause stains. It will be

In order to maintain the balance between the ink and the dampening water, the dampening water for lithographic printing generally has a surface tension lowering ability, suitability for continuous water supply, stain resistance, emulsification suitability, antiseptic / mildew resistance and rust resistance. , Various properties such as defoaming property and safety are required. In recent years, in lithographic printing, with the increase in speed and automation of printing machines, higher quality and stability of printed matter are required, and in such a situation, a continuous water supply method has become mainstream. However, this continuous water supply system is designed on the assumption that isopropyl alcohol (IPA) is used as the dampening water in order to exert its performance. This IPA is equivalent to Class 4 Alcohols of Dangerous Goods, and is also a Class 2 Organic Solvent for Organic Solvent Poisoning Prevention Regulations, and a moisturizer that complies with various legal requirements to realize a clean and safe working environment. Water is required. Under such a social environment, fountain solutions for lithographic printing that can substitute IPA have been devised in the printing industry. Generally, various surfactants and alcohol derivatives are used for these fountain solutions instead of IPA. ing. Although these dampening water compositions impart dampening water properties similar to IPA from the viewpoints of their surface tension, viscosity, and emulsification suitability, they have not been able to substitute the bactericidal action of IPA itself. Is. Conventional IP
Since A was used in the dampening water in an amount of several% to several tens%, the decay of the dampening water, which has not been a problem in the past due to its bactericidal action, becomes a major problem in the IPA substitute dampening water.

When the dampening water rots, it not only gives off a bad odor, but also produces slime and mold which adhere to the dampening water tank, the pipes to the printing machine, and the water boat of the printing machine. It may adhere to the plate surface and rolls and cause printing stains. In addition, discoloration of dampening water, pollution, pH change, and viscosity decrease, which also changes the physical properties of dampening water, impairing stable water supply and causing printing problems. Every time, the printing worker must clean or re-prepar the dampening water, which is an obstacle to the work. The generation of fungi in the fountain solution is caused by the growth of various fungi originally existing in the water, but the fountain solution composition for lithographic printing has a non-image area on the plate surface. For protection, various water-soluble polymer compounds represented by gum arabic and carboxymethyl cellulose are used as desensitizing agents. Due to the inclusion of these, the dampening water is prone to spoilage due to the growth of fungi during long-term storage and use as compared with ordinary water. Further, the growth of fungi depends not only on the components of the dampening water, but also on the pH, which generally causes a problem in the pH range of 4 to 8. Since a general fountain solution for lithographic printing except newspaper printing is usually used in a pH range of about 4 to 6, it is suitable for the growth of fungi.
It also matches the H range. For this reason, a dampening solution that does not rot is required.

For this reason, it has been proposed to add benzoic acid and its derivatives, phenol, formalin, sodium dehydrosulfate, 4-isothiazolin-3-one compound and the like as preservatives. However, many of these antiseptics and antifungal agents are not always sufficiently usable as a fountain solution for lithographic printing. Some have weak bactericidal properties that kill the bacteria themselves and weak bactericidal properties that suppress the growth of the bacteria, or because the fungi can tolerate during long-term use, they not only have the disadvantage that their ability does not last, There is at least one compositional constraint such as acceleration of ink emulsification, temperature instability, poor solubility in water, and harmfulness to the human body. I have not met. In terms of hardware, attempts have been made to remove dirt from the dampening water by installing a filter such as a filter in the dampening water circulation device, but it cannot be said to be sufficiently effective. In addition, if maintenance and inspection are insufficient, sludge and slime may accumulate in the filter used for filtration, which may rather create an environment suitable for fungal growth. Not enough to deal with. Similarly, fresh water is generally used as the circulating water for ink roll water flow, but to a lesser extent than the dampening water described above, if it rots and clogs the pipes, water flow becomes insufficient and roll temperature control becomes ineffective. , The temperature of the ink on the printing machine becomes unstable, which causes various obstacles such as stains.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a circulating supply device capable of stably supplying dampening water for lithographic printing and circulating water for ink rolls without decaying even after long-term storage or use. Is provided.

[0007]

That is, the present invention relates to a dampening water circulating and supplying device for lithographic printing, characterized by having an ozone sterilizing device. Further, the present invention relates to an ink roll circulating water supply device for lithographic printing, characterized by having an ozone sterilizer.

The ozone sterilizer uses the chemical nature of ozone's strong oxidizing action to introduce ozone gas into the dampening water or circulating water to sterilize and purify it and prevent the decay of circulating water such as dampening water. Carry. Further, in the device of the present invention, it is effective that the ozone sterilization device is an ozone generating part, a mixing part of ozone and dampening water or circulating water, and a device for controlling generation of ozone or mixing of ozone and dampening water. That is, since ozone has a strong oxidizing action, if the dampening water or the circulating water is continuously mixed with the ozone gas, the dampening water or the circulating water is excessively oxidized, and as a result, the dampening water or the circulating water is supplied. May cause rust on equipment, piping, printing machines, etc.
Further, by providing a device for measuring the ozone concentration and controlling the detected value so as to match the arbitrarily set ozone concentration, it becomes possible to more effectively and stably supply circulating water such as dampening water. . As the ozone concentration sensor, for example, a commonly used one is used in addition to the ultraviolet adsorption type. As means for mixing ozone and dampening water with circulating water, for example, a method of mixing the generated ozone gas with an air pump and introducing it into the circulating water according to the structure of a conventional circulation supply device, circulating water supply circulation A method of introducing and mixing ozone gas into the circulating water by the aspirator effect of the flow of the circulating water by the circulating pump for this purpose or other means may be used.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view showing the constitution of the dampening water circulation supply device of the present invention. The dampening water in the dampening water tank 1 is sucked up by the circulation pump 12, is sent to the water boat 4 of the printing machine through the pipe 5, and is returned to the dampening water tank 1 through the return pipe 2 again. Since the dampening water changes in quality due to the evaporation of water during printing and the influence of elution components from ink, paper, etc., it is generally a pH control device or electric conductivity control to control the condition of the dampening water. Device 6, IP
An A concentration control device 7 is provided, and a water supply unit 8, an IPA supply unit 9, a dampening water additive supply unit 10 are provided as necessary to stabilize the dampening water component, and the ozone generation supply device 1 is further provided.
4 and an ozone concentration management device 13 is installed as necessary. The circulating water is constantly monitored by the ozone concentration control device 13, and when the preset upper limit of ozone concentration is exceeded or when it is lower than the lower limit of ozone concentration, a warning is issued and the solenoid valve 23 is manually operated. The solenoid valve 23 may be automatically opened / closed by operating the opening / closing or by measuring the ozone concentration value.

FIG. 2 is an explanatory view showing the constitution of the ink roll circulating water supply device of the present invention. The circulating water in the circulating water tank 16 is sucked up by the circulating pump 22 and sent through the pipe 17 to one side of the ink roll, and is returned to the circulating water tank 16 through the return pipe 17 from the opposite side. The supply tank 16 is provided with a device for managing the state of circulating water, such as an ozone generation supply device 14 and an ozone concentration management device 13 and a pH management device, if necessary, and a supply pipe for diluting water or a pH adjusting agent, if necessary. It can be added from 20.

FIG. 3 is an explanatory view showing an example of the ozone generating and supplying device. The ozone gas generated by the ozone generator 24 is connected to the return pipe of the circulating water through the solenoid valve 23. Ozone gas is introduced and mixed into the circulating water without the need for a special mixing device by the aspiration action of the flow of the circulating water. Further, an ozone concentration management device 13 is installed in order to prevent the generation of rust or the like in the devices due to the excessive oxidation of the circulating water by ozone. Figure 4 shows
It is explanatory drawing which showed another example of the ozone generation supply apparatus. The ozone gas generated by the ozone generator 24 of the ozone generator 14 is introduced into the circulating water through the solenoid valve 23 by the air pump and mixed.

[0012]

INDUSTRIAL APPLICABILITY The dampening water and ink roll circulating water circulating and supplying apparatus of the present invention can very effectively sterilize and circulate circulating water by ozone gas without extensively modifying the conventional apparatus. Now, it has become possible to stably prevent circulating water from spoiling, which was difficult in the past, for a long period of time.

[Brief description of drawings]

FIG. 1 is a cross-sectional view illustrating the configuration of a dampening water circulation supply device.

FIG. 2 is a cross-sectional view illustrating the configuration of an ink roll water circulation supply device.

FIG. 3 is a cross-sectional view illustrating an ozone generation / supply device.

FIG. 4 is a cross-sectional view showing another example of an ozone generation and supply device.

[Explanation of symbols]

 3 plate cylinder 11 dampening water supply device 13 ozone concentration management device 14 ozone generation supply device

Claims (4)

[Claims] 1. A circulating supply device for dampening water for lithographic printing, comprising an ozone sterilizer. 2. An ink roll circulating water supply device for lithographic printing, comprising an ozone sterilizer. 3. The wet process for lithographic printing according to claim 1, wherein the ozone sterilizer comprises an ozone generator, a mixture of ozone and dampening water, and a device for controlling the generation of ozone or the mixing of ozone and dampening water. Circulation water supply device. 4. The lithographic printing ink roll circulation according to claim 2, wherein the ozone sterilizer comprises an ozone generating section, a mixing section for ozone and circulating water, and an apparatus for controlling generation of ozone or mixing of ozone and circulating water. Water supply device.