JPH0436268Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a sheet-fed printing press in which the paper feed cylinder of the paper feed section is also used as a back printing impression cylinder.

[Conventional technology]

Conventionally, sheet-fed double-sided printing machines have a structure in which paper is guided between a front-side printing blanket and a back-side printing blanket to simultaneously print on both sides (Japanese Patent Application Laid-Open No. 117956/1983). ), or a structure in which the front side is first printed, and then the paper is reversed by a reversing mechanism and the back side is printed.

[Problem that the invention attempts to solve]

However, since the former is a double-sided printing machine,
There are problems in that it is not possible to print on only one side, and since each blanket is made of a rubber cylinder, the sharpness of dots, dots, and dots are poor. Further, the latter has problems such as inconvenient switching operations of the reversing mechanism and printing accuracy inferior to that of single-sided printing machines.

The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a sheet-fed printing machine capable of double-sided printing without impairing the printing accuracy of front and back side printing.

[Means for solving problems]

The present invention provides a sheet-fed printing machine capable of double-sided printing, which is equipped with an impression cylinder and includes a front-side printing section that prints on the front side of printing paper, and a back-side printing section that prints on the back side of the printing paper. is adjacent to the impression cylinder, feeds the printing paper from the paper feed section, and acts as an impression cylinder for printing on the back side when printing on the back side; and a paper feed cylinder that is removably attached to the paper feed cylinder. The apparatus includes a blanket cylinder for printing on the back side, which is separated from the impression cylinder, and a plate cylinder for printing on the back side, which is removably attached to the blanket cylinder, and when printing on the back side, the printing paper is attached to the paper feed cylinder. The printing paper is received by a gripper and conveyed between the paper feed cylinder and the blanket cylinder to perform printing on the back side, and after printing on the back side, the printed paper is transferred from the paper feed cylinder to the impression cylinder. Features.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic diagram showing the arrangement of cylinders of a single-sided, multicolor, double-sided printing press. Reference numeral 1 in the figure indicates a paper feeding section, and this paper feeding section 1 has a paper insertion section 2 for conveying printing paper a. Further, reference numeral 3 in the figure is a paper discharge section that discharges the printing paper a, and between this paper discharge section 3 and the paper feed section 1, a first printing section 4 and a second printing section that perform surface printing are provided. 5 are arranged.

The first printing section 4 includes an impression cylinder 6 equipped with a paper picking device having paper picking claws 7, 8, etc. at symmetrical positions on the outer periphery.
and a plate cylinder 9 whose diameter is 1/2 that of the impression cylinder 6. 2 rubber cylinder 1
0, an ink section 11 disposed on the plate cylinder 9,
It is formed of a water portion 12 and the like.

Further, the second printing section 5 is equipped with a paper picking device having paper picking claws 14, 15, etc. at symmetrical positions on the outer periphery, and an impression cylinder 13 having the same diameter as the impression cylinder 6 of the first printing section 4. , a plate cylinder 16 whose diameter is 1/2 that of the impression cylinder 13, and a plate cylinder 16 whose diameter is 1/2 that of the impression cylinder 13, and are arranged so that they can be inserted into and removed from the impression cylinder 13 and the plate cylinder 16. It is formed of a blanket cylinder 17, an ink section 18 disposed on the plate cylinder 16, a water section 19, and the like.

Between the impression cylinder 6 of the first printing section 4 and the impression cylinder 13 of the second printing section 5, the printing paper a is transferred from the impression cylinder 6 to the impression cylinder 1.
A transfer cylinder 20 is provided for delivering the goods to 3. The diameter of this transfer cylinder 20 is formed to be the same as the diameter of each of the impression cylinders 6, 13, and paper picking devices having paper picking claws 21, 22, etc. are provided at symmetrical positions on the outer periphery.

Further, a paper feed cylinder 23 is disposed between the impression cylinder 6 of the first printing section 4 and the paper insertion section 2. This paper feed cylinder 23 is formed to have a diameter that is half the diameter of the impression cylinder 6. Further, in order to transfer the printing paper a to the impression cylinder 6, a paper picking device having a paper picking claw 24 and the like is provided in a notch cut out and formed on one side of the outer periphery. A blanket cylinder 26 having the same diameter is disposed in the paper feed cylinder 23 such that it can be inserted into and removed from the paper feed cylinder 23 and is spaced apart from the impression cylinder 6. Further, a plate cylinder 25 is provided, and the blanket cylinder 26 is arranged to be inserted into and removed from the plate cylinder 25. An ink section 27 and a water section 28 are in contact with the plate cylinder 25. The back side printing section 29 is configured in this way.

Further, the blanket cylinder 26 is swingably installed on the left and right frames 30 (see Fig. 2) of the printing press, and by swinging the blanket cylinder 26, blanket insertion and removal can be performed. It is configured so that

In the figure, reference numeral 31 is a feeder board, reference numeral 32 is a pair of riser rollers, and reference numeral 33 is a front cover for the printing paper a.

In the sheet-fed printing press configured as described above, the operation when performing double-sided printing will be described below.

The paper a transferred from the paper feed section 1 onto the feeder board 31 of the paper insertion section 2 is front-registered by the front plate 33, and is transferred by the riser roller 32 to the feeder board 31 of the paper insertion section 2. It is held in the paper holding claw 24. Then, the printing paper a is conveyed between the paper feed cylinder 23 and the blanket cylinder 26 and comes into contact with the blanket cylinder 26, thereby printing on the back side. At this time, the paper feed cylinder 23 functions as an impression cylinder for normal printing, and is formed of a rigid body.

Next, the printing paper a is released from the paper feed cylinder 23 by the opening operation of the paper gripping claw 24, and is transferred to the first printing section 4.
The paper is caught in the paper gripper 8 of the impression cylinder 6 and delivered to the impression cylinder 6.

At this time, in FIG. 1, after the paper is guided along the half circumferential surface of the impression cylinder 6 that is not the pressing surface,
The rubber cylinder 1 is guided along the pressing surface opposite to the above.
Contact with 0 prints the first color on the front side.
Next, after being transferred from the impression cylinder 6 to the transfer cylinder 20, it is guided to the impression cylinder 13 of the second printing section 5, and then transferred to the blanket cylinder 1.
7, the second color on the front side is printed.
Next, the paper is discharged by the paper discharge section 3, and double-sided printing is completed.

FIG. 3 is a schematic view showing another embodiment of the sheet-fed printing press according to the present invention shown in FIG. 2; Note that the same members as in FIG. 1 are given the same reference numerals, and detailed explanations will be omitted.

In this embodiment, a transfer cylinder 20 is provided between the impression cylinder 6 of the first printing section 4 and the impression cylinder 13 of the second printing section 5 in the first embodiment, but this transfer cylinder 20 is provided with an impression cylinder. By having the same function as that, it is possible to eliminate the need for an additional impression cylinder.

In addition, in the above-mentioned first and second embodiments,
Although this is a double-sided printing machine that prints two colors on the front side, other double-sided printing machines that print two or more colors on the front side, or double-sided printing machines that print two or more colors on the front side, or
It goes without saying that the present invention can also be applied to a color printing double-sided printing machine or the like.

[Effect of idea]

As mentioned above, this invention enables printing on the back side by conveying the printing paper between the paper feed cylinder and the blanket cylinder, so it is necessary to install an impression cylinder for printing on the back side. The overall structure of the printing press becomes more compact. In addition, by using the normal paper feed cylinder as an impression cylinder when printing on the back side, printing can be performed with sufficient printing pressure, resulting in good printing accuracy and clear printing even on paper with rough surfaces. You can perform printing. Furthermore, since a blanket cylinder is not used as the paper feed cylinder, there is no fear that ink will adhere to the printing paper during conveyance, thereby making it possible to prevent double printing. Further, since a gripper is not required on the blanket cylinder for printing on the back side, the blanket can be easily attached and replaced.

[Brief explanation of the drawing]

FIG. 1 is a schematic view showing the cylinder arrangement of a sheet-fed printing press according to the present invention, and FIG. 2 is a schematic view of the entire printing press of another embodiment of the sheet-fed printing press according to the present invention. 4, 5... Surface printing section, 6, 13... Impression cylinder, 2
3... Paper feed cylinder, 9, 16, 25... Plate cylinder, 10,
17, 26...Rubber cylinder, 29...Back side printing section.

Claims (1)

[Scope of utility model registration request] In a sheet-fed printing machine capable of double-sided printing, which is equipped with an impression cylinder and includes a front-side printing section that prints the front side of the printing paper, and a back-side printing section that prints the back side of the printing paper, the back-side printing section is configured to print the front side of the printing paper. There is a paper feed cylinder adjacent to the paper feed cylinder that feeds printing paper from the paper feed section and acts as an impression cylinder for back side printing when printing on the back side, and a paper feed cylinder that is removably attached to the paper feed cylinder and that acts as an impression cylinder for printing on the back side when printing on the back side. It is equipped with a blanket cylinder for printing on the back side that is separated from the cylinder, and a plate cylinder for printing on the back side that is removably attached to this blanket cylinder, and when printing on the back side, the printing paper is received by the gripper provided on the paper feed cylinder. The paper sheet is printed on the back side by being conveyed between the paper feed cylinder and the blanket cylinder, and after printing on the back side, the printed paper is transferred from the paper feed cylinder to the impression cylinder. Leaf printing machine.