JP2003225991A5 - - Google Patents

Description

Therefore, it is not possible to avoid the complication, upsizing, cost increase and the like of the apparatus, and there is a problem that the maintainability is also poor.
Moreover, since the apparatus is complicated and has a large number of ink kneading rollers, it is complicated and difficult to adjust the amount of ink supply and the amount of dampening water supplied to supply the appropriate amount of ink to the ink form roller. There is also the problem of requiring skill.

Here, in the inker, not all the ink is moving toward the downstream (plate cylinder), but there is also ink that returns upstream. As described above, in the inker in which the ink kneading roller is eliminated (simplified), since the ink fountain and the plate cylinder are close to each other, paper dust or the like adhering to the plate cylinder is mixed in the ink fountain by the return of the ink. May contaminate the ink.
Further, in a system using dampening water, since the ink fountain and the dampening fluid apparatus are close to each other, it is easy to generate the hyperemulsification of the ink and the mixing of the dampening water into the ink fountain due to the return of the overemulsified ink In the case of excessive, a large amount of water separated by the ink bottle adheres to the inking roller, causing roller stripping, which makes it impossible to properly supply the ink to the inking roller. In order to prevent this, precise adjustment of the dampening system is required, but its stable area is very narrow, and it can not be adjusted depending on the combination of ink and dampening solution used. In some cases.

Printing apparatus 20, similarly to the conventional printing apparatus, plate ink riding a printing plate wound around the cylinder 22 is transferred to the blanket cylinder (blanket cylinder) 24, the ink, thus the blanket cylinder to the impression cylinder 26 24 The printing is performed by transferring to a printing material P such as paper which is nipped and conveyed by both while being pressed by the printing medium.
Although the illustrated example uses the inker 10 of the present invention for the single-color printing apparatus 20 in order to simplify the description, the inker of the present invention is a multicolor printing of two or more colors by a known configuration. Of course, it may be used for printing devices.

As an example, an ink measuring and supplying means is exemplified using an anix roller and a doctor blade, the anix roller pulling out the ink, and the doctor blade scraping off the unnecessary ink to supply a predetermined amount of ink.
Alternatively, as shown in FIG. 2 (B), using the adjusting roller 34 which is disposed apart from the inking roller 14 and whose distance c and rotational speed can be adjusted, the distance c between the two rollers is adjusted. The ink of a constant film thickness may be drawn out by adjusting the rotation speed of.
Furthermore, as shown in FIG. 2 (C), is placed in contact with the ink fountain roller 14 equivalents, contact pressure (nip pressure) and with a rotational speed adjustable regulating roller 36, contact pressure and by adjusting the rotational speed of the regulatory roller 36 may be one that draws constant thickness of ink.

In the present invention, it is preferable to set the difference ΔRa in arithmetic average roughness of the surface of the inking roller 16 to 1 μm or less, from the viewpoint that the above-mentioned effects can be obtained better.
Further, for the same reason, it is preferable that the maximum arithmetic mean roughness Ra - m of the surface of the inking roller 16 be 2.5 μm or less.
Of course, in the ink supply device of the present invention, it is preferable to satisfy both the above-mentioned arithmetic average roughness difference ΔRa and the maximum arithmetic average roughness Ra-m.

[Preparation of emulsion ink]
(1) Preparation of Varnish The following materials were stirred / mixed to prepare three varnishes of Varnish A, Gel Varnish B, and Varnish C.
Varnish A: Maleated petroleum resin (Neopolymer 120 manufactured by Nippon Oil Co., Ltd.)
47 parts by weight
Spindle oil 53 parts by weight Gel varnish B: Rosin modified phenolic resin (Tamanol 354) Arakawa Chemical Industries
34 parts by weight
31 parts by weight of machine oil
Spindle oil 31 parts by weight
Aluminum stearate 4 parts by weight Varnish C: Gilsonite 25 parts by weight
Machine oil 75 parts by weight

For each printed materials thus obtained was measured and print density on the paper corresponding to the coarsest portion of the ink form rollers 16, and a print density on the paper corresponding to the smoothest portion, as described below Then, the density controllability and the density unevenness were evaluated.