JPS6120748A - Printing apparatus - Google Patents

Abstract

PURPOSE:To attain to enhance printing quality by always obtaining a sheet having a uniform printing thickness, by successively narrowing a roller surface width from an ink roller to a printing roller. CONSTITUTION:Ink 6 is transferred to a printing roller 2'' from an ink sump 4 through an ink roller 3 and transfer printing is applied to the sheet 5 on an impression cylinder 1. At this time, a large amount of ink 6 adhered to the side surface of the ink roller 3 is accumulated to the surface end parts of the ink roller 3 by centrifugal force due to the rotation of said roller 3 but, because the surface with of the printing roller 2'' is narrower than that of the ink roller 3, the ink 6' accumulated to the surface end parts of the ink roller 3 is not transferred to the printing roller 2'' and only a uniform amount of ink is transferred to the surface of the printing roller 2'' over the end parts thereof to always obtain a sheet having a uniform printing thickness. Furthermore, effect is more enhanced if intermediate ink rollers, of which the roll widths become successively narrow, are provided between the ink roller and the printing roller.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a printing apparatus that prints a pattern across the width of a roller surface using a letterpress or the like, or a pattern that uses the edge of the roller surface.

Structure of conventional examples and their problems General printing plates are classified into letterpress, lithographic, intaglio, and stencil.These types of printing use fluid ink in an ink reservoir→
Printing is performed by sequentially transferring the ink roller to the plate roller to the sheet.

An example of a conventional printing device will be described below.

FIG. 1 shows a side view of a conventional letterpress printing apparatus, in which 1 is an impression cylinder, 2 is a plate roller, 3 is an ink roller, 4 is an ink reservoir, 6 is a sheet, and 6 is ink.

Figure 2 shows a front view of Figure 1, and Figure 3 is a front view of another conventional example. The sheet 6 to be printed is held between the impression cylinder 1 and the plate roller 2 and is conveyed by the zero plate roller. 2 is supplied to the ink roller 3 at a rate of 1/kg, so the ink 6 is transferred and printed onto the sheet 6. At this time, the ink roller 23 is immersed in the ink 6 stored in the ink reservoir 4. The ink 6' adhering to the side surface of the ink row 23 is transferred to the side surface of the plate row 22 as a large amount of ink 6'' due to the action of centrifugal force accompanying the rotation of the ink row 23, and is transferred to the plate roller 2. sheet 6
When transfer printing is performed, the printing thickness on both end surfaces of the plate roller is extremely thick, and the printing thickness in the width direction of the two sides of the plate roller is uneven. Also, in FIG. 3, the surface width of the plate roller 2' is wider than the surface width of the ink row 23, but the ink 6' attached to the side surface of the ink row 23 is larger than that of the ink row 23.
There is a large amount of ink 6″ on the end face and both ends of the plate roller 2′.
As a result, the printing thickness becomes uneven as shown in Figure 2.
Print quality was getting worse.

Purpose of the Invention The present invention has been proposed in order to solve the above-mentioned conventional drawbacks, and is capable of transferring ink accumulated on the end face and both ends of the plate roller and ink roller onto a sheet while preventing it from being transferred to the next roller. It is an object of the present invention to provide a printing device that makes the ink thickness uniform in the width direction across two surfaces of a printed plate row.

Structure of the Invention The present invention provides a roller configuration in which the surface widths of the plate roller and ink roller are sequentially narrowed from the ink reservoir to the plate roller. This is a printing device that can make the printed ink thickness uniform by the above-described simple configuration in printing a pattern using two side edges.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a front view of a printing apparatus in one embodiment of the present invention, and FIG. 6 is a front view of a printing apparatus in another embodiment of the invention. In the drawings, the same parts as in the conventional example are given the same numbers.

In Fig. 4, 1 is an impression cylinder, 2'' is a plate roller, 3 is an ink roller, 4 is an ink reservoir, 6 is a sheet, and 6 is ink. It is shorter than the surface width.

The operation of the printing apparatus of this embodiment configured as described above will be explained below.

The impression cylinder 1 faces the plate roller 22'' through the sheet 6, and serves as a driving source for the sheet 10, and also serves as a sheet support when the plate roller 22'' transfers and prints the ink 6 onto the sheet 5. .

The ink 6 is transferred from the ink reservoir 4 through the ink roller 3 to the plate row 22'' and is transferred and printed onto the sheet 6. At this time, a large amount of ink 6 adhering to the side surface of the ink roller 3 is Due to the centrifugal force caused by the ink roller, the ink accumulates on the edge of the ink roller surface, but since the surface width of the plate roller 2'' is narrower than the surface width of the ink roller 3, the ink accumulated on the edge of the ink roller surface Since the ink 6' is not transferred to the plate roller 2'', only a uniform amount of the ink 6 is transferred to the surface of the plate roller 2!' up to the edge, and the ink 6 is transferred and printed onto the sheet 6.
The printing thickness is uniform over the entire width of the printed surface. Furthermore, since the amount of ink 6' accumulated on the end surface of the ink roller 3 varies depending on the rotational speed of the ink roller 3, the viscosity of the ink 6, etc., when a large amount of ink is accumulated, the fifth
By providing the intermediate ink roller 3' as shown in the figure, the ink 6' accumulated on the ink roller 3 is transferred to the intermediate ink roller 3', but not to the plate roller 2''.

Although only one intermediate ink roller 3' is provided in FIG. 6, a plurality of intermediate ink rollers 3' may be provided depending on the amount of ink accumulated.

Effects of the Invention As described above, in the printing apparatus of the present invention, by sequentially narrowing the roller surface width from the ink roller to the plate roller, excess ink accumulates on the end face of the roller, unlike in the conventional case, and is disposed of on both end faces of the plate roller. Since the printing thickness does not become significantly thicker, a sheet with uniform printing thickness can always be obtained, and the printing quality can be improved, which has a great practical effect.

[Brief explanation of drawings]

Fig. 1 is a side view of a printing device in a conventional example, Fig. 2 is a front view of Fig. 1, Fig. 3 is a front view of another conventional example, and Fig. 4 is a front view of another conventional example.
The figure is a front view of a printing device according to an embodiment of the present invention.
The figure is a front view of another embodiment.
... plate roller, 3...1110. Seat, 6.6',
6",...Ink. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure B Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] An impression cylinder that faces the plate roller via the sheet, the plate roller that prints ink on the sheet, and an ink roller group that supplies ink to the plate roller, the surface width of the plate roller and the ink roller group being A printing device configured to gradually narrow from the ink reservoir to the impression cylinder.