JPS61108557A - Ink supplying apparatus for printing apparatus - Google Patents

Abstract

PURPOSE:To make possible a printed matter having a constant density to be obtained always inspite of a presence of a temperature change and a printing speed change by providing a doctor rod and a spring means which energizes the doctor rod for approaching toward the outside periphery of a sqeegee roller. CONSTITUTION:A doctor rod 6 is provided in such a manner that it is engaged with a shaft 11 formed along a diameter of a squeegee roller 4 on a frame body 1 with a shift 7 provided to the both ends thereof, and displaceable in a direction of the sqeegee roller 4 relative thereto. Each doctor rod is energized in the direction to be approached toward the outside periphery of the squeegee roller 4 by a compression coil spring 16. A pre-load of this compression coil spring 16 is adjusted by an adjustment of a mounting position of a spring retainer 15 relative to a rod 14. In an aforesaid ink supplying apparatus a printing ink is flowed and supplied from an ink supplying pipe 17 onto the squeegee roller 4.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an ink supply device for a printing device, and more particularly to an ink supply device for rotary stencil printing.

Conventional technology As one of the ink supply devices used in rotary stencil printing machines, the ink reservoir is disposed in contact with the inner circumferential surface of a cylindrical plate cylinder at its outer circumferential surface, and rotates the ink reservoir around its own central axis. a squeegee roller that rotates in synchronization with the squeegee roller; and a doctor rod that is disposed substantially parallel to the axis of the squeegee roller and at a predetermined constant gap of 171 N from the outer peripheral surface of the squeegee roller. , an ink reservoir is formed in a wedge-shaped space formed between the squeegee roller and the doctor rod, and the printing ink supplied to the ink reservoir is caused to pass through the gap as the squeegee roller rotates. An ink supply device which acts to deposit a layer of a predetermined thickness on the outer circumferential surface of the squeegee roller and transfer it to the inner circumferential surface of a cylindrical plate cylinder is disclosed in Japanese Patent Application No. 53, filed by the same applicant as the present applicant. -128043
This method has already been proposed in Japanese Patent Application Laid-Open No. 55-55889.

In the ink supply device as described above, the amount of ink supplied from the ink reservoir to the inner peripheral surface of the doctor rod is determined by the size of the gap between the squeegee roller and the doctor rod.
This determines the ink density.

Problem to be Solved by the Invention If the hardness of the printing ink is constant, a constant I1 degree printed matter can be obtained by keeping the gap constant, but printing inks generally change hardness depending on the temperature. However, it becomes hard when the temperature is low in winter, and soft when it is warm in summer. Therefore, if the gap is constant, the printing density will be lower than the standard density at low temperature, and on the contrary, at high temperature, the printing density will be 11 degrees. It tends to be higher than normal.

Furthermore, even if the amount of ink supplied to the inner circumferential surface of the doctor rod is constant, the printing density changes depending on the rotational speed of the doctor rod, in other words, the printing speed. During printing, the print density tends to be higher than the standard 11 degrees.

The object of the present invention is to provide an ink supply device for printing 1' which can always obtain printed matter with a constant density regardless of changes in temperature and printing speed, and does not require a special control device. It is an object of the present invention to provide an ink supply device that achieves this objective without having to do so.

Means for Solving the Problems According to the present invention, the cylindrical plate is disposed in contact with the inner circumferential surface of the cylindrical plate cylinder at its outer circumferential surface, and the cylindrical plate is disposed around its central axis. A squeegee roller that rotates in synchronization with the rotation of the cylinder, a doctor O-do extending substantially parallel to the axis of the squeegee roller and movable in the radial direction of the squeegee roller, and the doctor O-do. This is accomplished by an ink supply device of a printing device having spring means for biasing the squeegee roller toward the outer circumferential surface of the squeegee roller.

Functions and Effects of the Invention According to the above-described configuration, the gap between the squeegee roller and the doctor rod has two forces: a force applied to the doctor rod by printing ink trying to pass through the gap, and a spring force applied to the doctor rod by the spring means. The force applied to the doctor rod by the printing ink passing through the gap increases when the printing ink is hard and when the passing speed is high, as the stress increases. Therefore, when the printing ink is hard, and when the passing speed is high, in other words, when the printing speed is high, the gap becomes larger and the ink is not supplied to the inner peripheral surface of the circular or n-shaped plate cylinder. The amount increases;
On the contrary, when the printing ink is soft or when the printing speed is slow, the gap becomes smaller and the amount of ink supplied to the inner peripheral surface of the cylindrical plate cylinder decreases. Accordingly, since the spring force applied by the spring means to the doctor rod is appropriately determined, changes in printing degree due to changes in printing ink hardness and changes in printing speed are compensated for by changes in the gap, and regardless of these changes. Printed matter with a constant density can be obtained at all times.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail by way of embodiments with reference to the accompanying drawings.

1 to 3 show one embodiment of an ink supply device for a printing apparatus according to the present invention. In these figures,
Reference numeral 1 designates a frame body, which has a pair of side plates 2 and 3 provided parallel to each other, and is fixedly supported by a machine frame of a printing device (not shown).

A squeegee roller 4 and a doctor rod 6 are arranged parallel to each other between the side plates 2 and 3.

The squeegee roller 4 has shaft portions 5 provided at both ends thereof.
It engages with a round hole 10 formed in the frame 1 and is rotatably supported by the frame 1 around its own central axis, and its outer circumferential surface slides against the inner circumferential surface of the cylindrical plate body. ing. A sprocket 8 is attached to one shaft portion 5 of the squeegee roller 4, and an endless transmission belt is engaged with the sprocket. The endless transmission belt 9 rotates the squeegee roller 4 in the same direction as the rotation direction of the cylindrical plate barrel, that is, counterclockwise in the figure, in synchronization with the rotation of the cylindrical plate barrel. There is.

The doctor Otsudo 6 engages with an elongated hole 11 extending in the radial direction of the squeegee roller 4 formed in the frame 1 with shaft portions 7 provided at both ends of the doctor O. It is provided so that it can be moved in the direction.

A block 12 is attached to each shaft portion 5 of the squeegee roller 4 so as to be rotatable with respect to the shaft portion 5, and a block 13 is respectively attached to the shaft portion 7 of the doctor rod 6 so as to be rotatable with respect to the shaft portion 7. There is.

Each of the blocks 13 is provided with a rod 14 passing through it in the axial direction, and each of the rods is fixed to the block 12 with a screw at one end. A spring retainer 15 is screwed to the other end of each of the rods 14 so that the mounting position can be adjusted, and a compression coil spring 16 is mounted between the spring retainer 15 and the block 13, respectively. The compression coil springs 16 each have a doctor 0 and a squeegee 6.
- The preload of the compression coil spring 16 is applied to the rod 1 of the spring retainer 15.
Adjustment is made by adjusting the mounting position relative to 4.

In the ink supply device configured as described above, printing ink is supplied onto the squeegee roller 4 from the ink supply vibrator 17. As the squeegee roller 4 rotates, this printing ink is deposited in an ink pool P formed in a patterned space between the squeegee roller 4 and the doctor rod 6.
and forms a fluid ink mass. Ink pool P
As the squeegee roller 4 rotates, the fluid ink lump pulls the doctor rod 6 away from the squeegee roller 4 against the spring force of the compression coil spring 16, passes through the gap 20 created between the two, and is applied to the squeegee roller 4. It is deposited on the outer peripheral surface in a layer having a thickness determined by the size of the gap and is sent to the inner peripheral surface of the cylindrical plate cylinder.

The gap 20 between the squeegee roller 4 and the doctor rod 6 at this time is determined by the balanced relationship between the force applied to the doctor rod 6 by the printing ink trying to pass through the gap and the spring force applied to the doctor rod 6 by the compression coil spring 16. When the force exerted on the doctor rod 6 by the printing ink passing through the gap 20 is large, the force increases, and the amount of ink supplied to the inner peripheral surface of the cylindrical plate cylinder increases accordingly. The force exerted on the doctor rod 6 by the printing ink trying to pass through the gap 20 increases when the printing ink is hard and when the passing speed is high, as stress such as shear stress increases. When the ink is hard, or when the passing speed is high, that is, when the printing speed is high, the WA gap 20 increases, as shown in FIG. When the ink is soft and when the printing speed is slow, the gap 20 becomes smaller, as shown in FIG.

As mentioned above, by changing the gap according to the hardness of the printing ink and the printing speed, changes in the printing density due to changes in the hardness of the printing ink and changes in the printing speed are compensated for, and the density is always constant without being affected by these changes. You will be able to obtain printed matter.

Although the present invention has been described in detail with respect to specific embodiments above, the present invention is not limited thereto.
It will be apparent to those skilled in the art that various embodiments are possible within the scope of the invention.

[Brief explanation of drawings]

FIG. 1 is a front view showing one embodiment of the ink supply device of the printing apparatus according to the present invention in a state where the gap is large, and FIG. FIG. 3 is a front view showing a state when the gap between the supply device is small, and FIG. 3 is a schematic perspective view of the ink supply device according to the present invention shown in FIGS. 1 and 2. DESCRIPTION OF SYMBOLS 1... Frame body, 2.3... Side plate, 4... Squeegee roller, 5... Shaft part, 6... Doctor rod, 7...
・Shaft part, 8... Sprocket, 9... M (ta transmission belt, 10... Round hole, 11... Long hole, 12.13
...Block, 14...0 Tsudo, 15...Spring retainer, 16...Compression coil spring, 17...Ink supply pipe, 20...Gap, O...Cylindrical plate cylinder

Claims (1)

[Claims] a squeegee roller that is disposed in contact with the inner circumferential surface of the cylindrical plate cylinder at its outer peripheral surface and rotates around its own central axis in synchronization with the rotation of the cylindrical plate cylinder; A printing device comprising a doctor rod that extends substantially parallel to the squeegee roller and is movable in the radial direction of the squeegee roller, and spring means that biases the doctor rod in a direction approaching the outer peripheral surface of the squeegee roller. ink supply device.