JP3511326B2 - Printing method and printing apparatus using aqueous ink - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing method and a printing apparatus using a low-viscosity water-based ink and a dampening oil.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a conventional printing method.
It is a figure which shows schematic structure of a waterless offset printing system.
This printing method enables lithographic printing without using dampening water. Plate 1 on the plate cylinder 16a
6b is attached. The plate 16b has a non-image area formed of an ink repellent material such as a silicone layer so that the ink adheres only to the image area even if ink is spread over the entire surface of the plate. The ink in this printing method,
High viscosity ink is used. This is to improve halftone dot reproducibility when using a planographic printing plate. The high-viscosity ink is, for example, a mixture of a phenol resin and an alkyd resin with a paraffin solvent.

From the ink source roller 12 to the calling roller 1
When the ink is supplied to 3, the ink is kneaded by the plural kneading rollers 14 and then supplied to the inking roller 15. Here, the reason why the plural kneading rollers 14 knead the ink is to obtain various physical properties of the ink necessary for printing. Further, the plurality of inking rollers 15 are used to prevent the occurrence of ghost (a phenomenon in which light and shade are mixed) during printing. Then, the ink is supplied to the blanket 17b via the plate 16b, and printing is performed by applying a printing pressure to the printing substrate 19 with the impression cylinder 18.

[0004]

However, in the above-mentioned conventional technique, since a plurality of kneading rollers 14 and inking rollers 15 must be used, the total number of rollers is very large, and the structure of the inking system is large. As a result, there is a problem that the structure of the printing apparatus becomes complicated. As a result, there are problems that printing conditions become complicated and cleaning becomes difficult.

The present invention has been made to solve the above problems, and an object of the present invention is to simplify printing conditions, cleaning, and downsizing of an apparatus.

[0006]

In order to achieve the above-mentioned object, the invention of claim 1 provides a water-based ink on a lithographic plate on which a hydrophilic image-forming portion and a lipophilic non-image-forming portion are formed. Along with the supply, an oily substance is supplied to the planographic plate to which the aqueous ink has been supplied. Claim 2
Of the invention, a lithographic plate on which a non-image area having a hydrophilic image area and a non-image area having lipophilicity is formed, an aqueous ink supply means for supplying an aqueous ink to the lithographic plate, and the aqueous ink is supplied to the lithographic plate. And an oily substance supply means for supplying an oily substance to the lithographic plate.

[0007]

In the present invention, a water-based ink is used in the printing method using a lithographic plate. Further, the supply of the oily substance prevents the ink from adhering to the non-image area of the plate.
Therefore, printing can be performed without providing a large number of rollers, and the inking system and thus the printing apparatus can be simplified.

[0008]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a first embodiment of a printing method using a water-based ink according to the present invention. A water-based ink is stored in the ink pan 21. A part of the finisher roller 22 is disposed inside the ink pan 21 and is in contact with the plate 16b. Further, an oily substance (fountain oil) is stored in the oil pan 23.
The oil source roller 24 is partially arranged in the oil pan 23 and is in contact with the plate 16b. The plate 16b is attached to the plate cylinder 16a. The plate 16b is, for example, a conventionally well-known PS plate in which the image is positive-negative inverted, and the image area has hydrophilicity and the non-image area has lipophilicity. The plate 16b has, for example, a hydrophilic layer formed on a support, and a diazo compound-based photosensitive resin formed on the hydrophilic layer. The plate 16b is produced by process decomposition, plate collection, or the like by the same steps as those of the conventional waterless offset plate.

The blanket 17b is made of rubber or the like and is attached to the blanket cylinder 17a. The blanket 17b is in contact with the plate 16b,
It is for transferring the ink supplied to the plate 16b to the printing substrate 19. Further, the impression cylinder 18 is the printing substrate 1.
By pressing the blanket 17b via 9, the printing pressure is applied.

The water-based ink stored in the ink pan 21 is a low-viscosity water-based ink that does not dissolve in the dampening oil in the oil pan 23, and is, for example, water-based flexo ink. The viscosity is about 0.2 to 10 ps, which is about 1/200 of the viscosity of the conventional oil-based ink. The composition of the water-based ink is, for example, 10 to 20% by weight of ink pigment, 10 to 20% by weight of acrylic resin, 1% by weight of polyethylene WAX, 2% by weight of IPA, 15 to 20% by weight of propylene glycol, and water. Is a mixture of 45 to 55% by weight. The content of the acrylic resin in the water-based ink according to the present invention is smaller than that of conventionally known inks, and thus the viscosity of the ink is low.

The composition of the water-based ink in the examples is 13% by weight of cyanine blue, 3% by weight of extender pigment, 18% by weight of acrylic resin, 1% by weight of WAX and 2% of IPA.
Wt%, propylene glycol 19 wt%, water 44
It was set to% by weight. At this time, the viscosity is 2 ps and the surface tension is 3
It was 2 dyn / cm, and the flash point was 70 ° or higher (becomes non-hazardous material). In addition, when there are many ink pigments, an anti-wrapping agent is mixed. Also, instead of propylene glycol,
Ethylene glycol, dipropylene glycol, triethylene glycol monobutyl ether, etc. may also be used.
On the other hand, the dampening oil stored in the oil pan 23 is highly viscous, for example, medium.

In the above printing method, first, the finisher roller 22 is rotated and the water-based ink in the ink pan 21 is supplied to substantially the entire surface of the plate 16b. At that time, the water-based ink is held on the image area (hydrophilic layer) of the plate 16b. After the water-based ink is supplied to the plate 16b, the oil source roller 24 is rotated and the dampening oil in the oil pan 23 is supplied to substantially the entire surface of the plate 16b. The dampening oil prevents the water-based ink from adhering to the non-image area of the plate 16b. Then, the water-based ink is transferred from the plate 16b to the printing substrate 19 via the blanket 17b. With this printing method,
Since the ink of low viscosity is used, the inking system can be simplified and the space of the device can be saved. Further, since the high-viscosity dampening oil is used, it is possible to suppress the occurrence of defects due to dirt.

FIG. 2 is a diagram showing a second embodiment of a printing method using a water-based ink according to the present invention. The second embodiment is different from the first embodiment in that the ink is not directly supplied to the plate 16b from the finisher roller 22 and the oil source roller 24, but the ink is applied to the plate 16b via the ink forming roller 15 respectively. Is to be supplied.

Next, the printing procedure will be described based on the second embodiment. First, the plate 16b is attached to the plate cylinder 16a, and the blanket 17b is attached to the blank cylinder 17a. Further, the dampening oil described above is supplied to the oil pan (FIG. 1), and the water-based ink described above is supplied to the ink pan 21. And the oil key 2
Open 5 and set the key position. Next, the plate cylinder 16a is rotated while the finisher roller 22 is in contact therewith. Then accelerate to knead the dampening oil. Next, the blanket cylinder 17a and the impression cylinder 18 are brought into contact with each other to start printing. After starting printing, the amount of ink is adjusted by appropriately changing the finisher pressure and the number of revolutions while confirming the ink transfer condition. When ink loss occurs, the viscosity of dampening oil and the supply amount are adjusted.

At the end of printing, the speed is lowered to the stop state, and after the plate cylinder 16a is stopped, the impression cylinder 18, the blank cylinder 17a,
Also, the contact of the finisher roller 22 is released. Edition 1
6b is removed from the plate cylinder 16a and washed. Further, the inking roller 15 and the finisher roller 22 are washed. Further, the blanket 17b and the ink pan 21 are washed. When the printing is completely finished, the oil key 25 and the oil source roller 24 are also washed.

The present invention can be variously modified within an equivalent range. For example, as the ink supply system, besides the system shown in the embodiment, it is also possible to use a finisher bank system or an anilox roller system.

[0017]

According to the present invention, it is possible to perform printing without providing a large number of rollers, and it is possible to achieve simplification and space saving of the inking system, and by extension, the printing apparatus.
In addition, cleaning of the inking system can be facilitated.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of a printing method using a water-based ink according to the present invention.

FIG. 2 is a diagram showing a second embodiment of a printing method using a water-based ink according to the present invention.

FIG. 3 is a diagram showing a schematic configuration of a waterless offset printing method, which is an example of a conventional printing method.

[Explanation of symbols]

15 Inking roller 16a plate cylinder 16b version 17a Blanc body 17b blanket 18 impression cylinder 19 Printing substrate 21 ink pan 22 Finisher roller 23 oil pan 24 Oil source roller 25 oil key

─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-6-1088 (JP, A) JP-A-58-140288 (JP, A) JP-A-58-16883 (JP, A) JP-A-51- 31509 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B41M 1/06 B41N 3/08 B41F 7/02

Claims (2)

(57) [Claims] 1. A water-based ink is supplied to a lithographic plate on which a hydrophilic image area and a lipophilic non-image area are formed, and an oily substance is supplied to the lithographic plate supplied with the water-based ink. A printing method using a water-based ink. 2. A lithographic plate on which a hydrophilic image area and a lipophilic non-image area are formed, an aqueous ink supply means for supplying aqueous ink to the lithographic plate, and the aqueous ink is supplied to the lithographic plate. An oily substance supplying means for supplying an oily substance to the lithographic plate after the printing is performed.