JPH0655725A - Printing machine - Google Patents

Abstract

PURPOSE:To furnish a flat bed type offset printing machine which reduces nonuniformity in print and improves responsiveness to a feedback to a fountain roller. CONSTITUTION:In regard to a printing machine equipped with a fountain roller, an inking roller 5 and a printing plate 7, a printing machine having a construction wherein the diameter of the inking roller 5 is so set that a roller surface thereof can cover a printing area of the printing plate in one rotation or less and a prescribed roller surface of the inking roller 5 always corresponds to an image part 9 and a non-image part 10 in the printing area of the printing plate 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flatbed offset printing machine for producing a color filter used in a liquid crystal display device by printing.

[0002]

2. Description of the Related Art As a printing machine for printing a normal color filter, a flatbed type offset printing machine as shown in FIG. 14 is used. This printing machine comprises a fountain roller 1, an ink kneading roller 4 and an inking roller 5. Next, the operation will be described. As shown in FIG.
From the calling roller 2 to the predetermined rotation angle and thickness, the fixed amount of ink 3 is taken and supplied to the ink kneading roller 4,
Knead together with the inking roller 5 until the film becomes uniform.

After that, the gantry 6 is moved to supply ink from the inking roller 5 to the image portion of the printing plate 7 (inking). After the ink is supplied, the ink is returned to the original position, and is uneven for the next inking. Knead the ink until it disappears.
The above operation is repeated until printing is completed.

[0004]

The above-mentioned prior art has the following problems. (1) In a conventional printing machine, it is general to use an inking roller having a diameter that has a short roller surface with respect to a printing area (length in a printing direction) of a printing plate. Therefore, when performing inking, the inking roller rotates one or more times. For this reason, the image in the portion that has entered the second rotation is dragging the state of the ink film that has been captured in the first rotation, so unevenness (ghost) occurs in inking and printing unevenness occurs. (2) The ink film on the surface of the inking roller is uneven when the ink is returned to the ink kneading roller section after finishing the inking. In order to eliminate this unevenness,
For the ink kneading rollers, it is necessary to combine a plurality of rollers each having a different diameter and to knead the rollers for a predetermined time, which lowers the workability of the printing machine. (3) Further, as described above, there are a plurality of ink kneading rollers, and the ink is on the surfaces of all the rollers. A large amount of this ink delays the response (increase / decrease of the film on the printed matter) to the feedback (ink increase / decrease instruction) to the pot roller when managing the ink film of the printed matter. As a result, defective printed matter is produced. In addition, more defective prints will be produced for those that need to balance multiple colors at the same time, such as a three-color machine.

It is an object of the present invention to provide a flatbed type offset printing machine in which uneven printing is reduced and responsiveness to feedback to the pot roller is improved.

[0006]

[Means for Solving the Problems]

(1) The inking roller is made sufficiently thick with respect to the printing area (length in the printing direction) of the printing plate so that the printing area can be covered by one rotation of the inking roller or less. (2) If an ink kneading roller is used, it should have the same diameter as the inking roller, or an integral multiple thereof. (3) The ink film (14 in Fig. 3) on the pot roller is 2μ
The ink (15 in FIG. 3) on the entire surface of an inking roller (ink kneading roller if there is an ink kneading roller) in contact with this is thinly fed to about 4 μm. (4) As a method of using the above apparatus, when the inking roller rolls on the printing plate, the predetermined position on the surface of the inking roller is controlled so as to correspond to the predetermined position on the printing plate. In addition, the streaks (ink marks) on the surface of the inking roller, which are formed when the inking roller receives the ink from the pot roller (or the kneading roller when there is a kneading roller), and then when the ink is separated from the image area on the printing plate. Use it by controlling the rotation angle of the roller so that it goes out of the room.

[0007]

[Action]

(1) Since the inking roller is inked on the plate surface within one rotation, a new surface of the roller is always used, and unevenness (ghost) during inking does not occur. (2) Since the ink is supplied to the entire surface of the inking roller (of the kneading roller, if there is a kneading roller), the work of kneading and uniformly spreading is unnecessary, and almost simultaneously with the feedback of the pot roller (roller 1 The effect can be obtained only for the rotation time). (3) Since the position where the inking roller surface and the printing plate surface contact is always constant, and the part where ink is taken and the part where it is not on the applying roller do not mix, the part where ink is taken (on the plate surface) No variation in the ink film occurs in the image area). Therefore, printing unevenness (color unevenness caused by ink supply unevenness within the same pattern) does not occur.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIGS. In the figure, 1 is a fountain roller, 4 is an ink kneading roller, 5 is an inking roller, 6 is a pedestal, 7 is a printing plate, 8 is a mark of ink on the roller, 9 is an image portion of the printing plate, and 10 is a printing plate. Non-image area, 11 is the roller surface of the inking roller 5 corresponding to the non-image area 10, 12 is the roller surface of the inking roller 5 corresponding to the image area 9, 13 is the printing area of the printing plate 7, and 14 is the pot. An ink film on the roller 1, 15 is an ink film on the inking roller 5, 16 is a blanket cylinder, and 17 is an object to be printed.

The first embodiment shown in FIG. 1 is a vase roller 1
Also, one inking roller 5 is provided, and the ink kneading roller 4 is not provided. The diameter of the inking roller 5 is 100φ, and the printing size of the printing plate 7 is 300 × 30.
It is 0. Therefore, the roller surface of the inking roller 5 (length in the printing direction: 314) is the printing area 1 of the printing plate 7.
3 (length in the printing direction: 300) can be covered in one rotation or less.

As shown in FIG. 2, the printing area 13 has an image portion 9 and a non-image portion 10. The roller surface of the inking roller 5 rolling on the printing plate 7 has an ink film on the image portion 9. And the roller surface 12 from which the ink film is removed and the roller surface 11 corresponding to the non-image area 10 where the ink film remains. Therefore, by keeping the position where the surface of the inking roller 5 and the plate surface of the printing plate 7 contact at all times constant, that is, the roller surfaces 12 and 11 of the inking roller 5 are set to the image area 9 and the non-image of the printing plate 7. By always corresponding to the portion 10, a portion where ink is taken and a portion where ink remains on the surface of the inking roller 5 do not coexist, so that there is no variation in the ink film and therefore no printing unevenness.

Next, the operation sequence of the first embodiment will be described with reference to FIGS. Figure 4: Ink is applied from the fountain roller 1 to the entire surface of the inking roller 5. Figure 5: Stop the rotation of the fountain roller 1 and raise the inking roller 5 above the fountain roller 1 and lock it against rotation. FIG. 6: The pedestal 6 is moved onto the printing plate 7, and at the position where the ink mark 8 on the surface of the inking roller 5 comes immediately before the printing area 13 of the printing plate 7, the inking roller 5 is lowered to the printing plate 7. Contact.

FIG. 7: The pedestal 6 is further moved, ink is supplied from the inking roller 5 to the printing plate 7, and the pedestal 6 is stopped at a position where the inking roller 5 makes one rotation or at a position where the inking roller 5 leaves the printing area. Then, the inking roller 5 is raised and locked. FIG. 8: The pedestal 6 is moved in the opposite direction and returned to the position shown in FIG. After that, inking is performed in the state of FIG. 4 and the same operation is repeated.

In the second embodiment shown in FIG. 9, one pot roller 1, one ink kneading roller 4 and one inking roller 5 are provided, and the ink kneading roller 4 and the inking roller 5 have the same diameter. Has become. The operation sequence of the second embodiment is the same as that described in the first embodiment.
In addition, by providing the ink kneading roller 4, the ink film 15 on the surface of the inking roller 5 (see FIG. 3)
Is more uniform and the quality of printing is improved.

In the third embodiment shown in FIG. 10, one fountain roller 1 is provided with two inking rollers 5, and the operation sequence is basically the same as that described in the first embodiment. It is the same. However, since there are two inking rollers and one pot roller, the two inking rollers 5 move the rack 6 to the left and right, and receive ink separately from the pot roller 1 with a time lag. . In the fourth embodiment shown in FIG. 11, one ink fountain roller 1 is provided with two ink kneading rollers 4 and two inking rollers 5, and the operation sequence is described in the first embodiment. It is basically the same as what was done. Note that the two ink kneading rollers integrally move to the left and right, and separately receive ink from the fountain roller 1 with a time lag.

The fifth embodiment shown in FIGS. 12 and 13 has the same number of rollers as the fourth embodiment of FIG. 11, but the pot roller 1 is provided above the printing machine in consideration of workability. is there. In addition, the ink kneading roller 4 can be moved up and down in order to facilitate the rotation control of the inking roller 5.
At the rising position of the ink kneading roller 4 (FIG. 12), the ink is received from the fountain roller 1, and at the lower position of the ink kneading roller 4 (FIG. 13), the ink is supplied from the ink kneading roller 4 to the inking roller 5. It should be noted that the third to fifth embodiments are provided with two inking rollers 5 or each two.
Since the book ink kneading roller 4 and the inking roller 5 are provided, the machine operating rate is improved as compared with the first and second embodiments. Further, the correspondence between the position of the roller surface of the inking roller 5 and the position of the plate surface of the printing plate 7 described with reference to FIG. 2 may be practically equal to a deviation of about 2 mm (when the roller diameter is 100φ).

[0016]

[Effects of the Invention] Vase roller, inking roller,
In a printing machine equipped with a printing plate, the diameter of the inking roller has a roller surface capable of covering the printing area of the printing plate with one rotation or less, and an image portion and a non-image in the printing area of the printing plate. The following effects are obtained by the fact that a certain roller surface of the inking roller always corresponds to the part. (1) The thin portion of the ink film on the roller that is taken off by the plate as the image portion and the thick portion that remains without being removed due to the non-image portion may be mixed through the kneading mechanism and the feeding mechanism. Therefore, the ink film can maintain the uniformity in each part.

Therefore, even after the ink is supplied (after one rotation of the roller), printing unevenness (due to unevenness of the thickness of the ink film in the image area) does not occur. (2) When the printed matter that has been printed is inspected and the inspection result is fed back to the ink supply roller, conventionally, the desired printed matter was obtained only after kneading for several minutes and after printing a few more sheets. In the printing machine of the present invention, a desired printed matter can be obtained immediately after feedback, so that the density management and automatic control of the printed matter can be facilitated.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is a diagram showing a state of a roller surface when an inking roller supplies ink to a printing plate.

FIG. 3 is a diagram showing a state in which the ink is transferred from the fountain roller to the inking roller in the present invention.

4 is a diagram showing a first stage of an operation sequence of the printing machine shown in FIG.

FIG. 5 is a diagram showing the next step of FIG. 4;

FIG. 6 is a diagram showing the next step of FIG. 5;

FIG. 7 is a diagram showing the next step of FIG. 6;

FIG. 8 is a diagram showing the next step of FIG. 7;

FIG. 9 is a configuration diagram of a second embodiment of the present invention.

FIG. 10 is a configuration diagram of a third embodiment of the present invention.

FIG. 11 is a configuration diagram of a fourth embodiment of the present invention.

FIG. 12 is a diagram showing a state in which ink is supplied from the pot roller to the ink kneading roller in the fifth embodiment of the present invention.

13 is a diagram showing a state where ink is supplied from an ink kneading roller to an inking roller in the printing machine shown in FIG.

FIG. 14 is a configuration diagram of a conventional flatbed offset printing machine.

FIG. 15 is a diagram showing a state in which ink is called from a pot roller by a calling roller in a conventional printing machine.

[Explanation of symbols]

 5 Inking Roller 7 Printing Plate 9 Image Area of Printing Plate 10 Non-Image Area of Printing Plate 11 Inking Roller Surface Corresponding to Non-Image Area 12 Inking Roller Surface Corresponding to Image Area 9 13 Printing Area of Printing Plate

Claims (2)

[Claims] 1. A fountain roller, an inking roller,
In a printing machine equipped with a printing plate, the diameter of the inking roller has a roller surface capable of covering the printing area of the printing plate with one rotation or less, and an image portion and a non-image in the printing area of the printing plate. A printing press, characterized in that a certain roller surface of the inking roller always corresponds to a part. 2. The printing machine according to claim 1, wherein an ink kneading roller is provided between the fountain roller and the inking roller, and the diameter of the ink kneading roller is equal to or a multiple of the diameter of the inking roller.