JPH05254106A - Rotary extra printing machine - Google Patents

Abstract

PURPOSE:To carry out initial setting in extra printing easily. CONSTITUTION:A register mark of a previous printed matter printed on a material 3 to be printed is detected with a scanning head 12 at the time of initial setting for starting extra printing. A rotary position of a printing plate cylinder 6 is detected from an encoder 11, and a control part 14 calculates initial shift of registration from those detected values. Then, the printing plate cylinder 6 is separated, and a compensator roller 7 is operated to correct the initial shift of registration. The printing plate cylinder 6 is restored to an original position to carry out extra printing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary printing apparatus for performing additional printing.

[0002]

2. Description of the Related Art In the case of printing with a plurality of colors, first, a paper on which several colors have been printed is set again in the printing apparatus, and additional printing is performed to print the remaining colors. FIG. 4 is a diagram showing an example of the configuration of such a rotary printing press. The material to be printed 3 unwound from the unwinding part 1 is wound around the printing impression cylinder 20, and the material to be printed 3 is arranged on the circumference of the printing impression cylinder 20 by the printing impression cylinder 20. Printing is performed by the printing plate cylinder 21 which is driven to rotate. In FIG. 4, one printing impression cylinder 20 is provided with two printing plate cylinders 21 driven by the printing impression cylinder 20.
The two printing plate cylinders 21 rotate in synchronism with each other because the common printing cylinders 20 rotate mechanically.

When performing four-color printing with the above apparatus, first, two
After printing the colors on the two printing plate cylinders 21, the original web winding unit 2 winds it up, sets it in the original paper unwinding unit 1, and prints the remaining two colors on the printing plate cylinder 21 again. This is called reprint. When performing additional printing, the previous printing (this is called first printing)
Color misregistration occurs unless additional printing is performed at the same position. For this reason, conventionally, as shown in FIG. 4, once the printing medium 3 to be additionally printed is set in the printing apparatus, the printing substrate 3 is cut to align the printing plate cylinder 21 with the previous printing. Prepress and printing plate cylinder
After correcting the misalignment of 21 positions (this is called misregistration) and then reconnecting them, additional printing was performed.

[0004]

However, in order to correct the misregistration in this way, it is time-consuming and time-consuming to cut and then reconnect the print-receiving bodies 3 for further cutting and connecting. The tension of the printing medium 3 when it is applied to the printing device becomes zero, and the printing performed until the tension is raised to a predetermined value must be discarded, resulting in an increase in waste paper.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a rotary overprinting printing apparatus which can easily perform initial setting during additional printing.

[0006]

To achieve the above object, a driving cylinder, a plurality of printing impression cylinders driven by the driving cylinder, and a printing plate cylinder provided in pair with each printing impression cylinder, An object to be printed conveyed between the printing plate cylinder and the printing impression cylinder while being printed by the printing plate cylinder, a register mark detector for detecting a register mark printed on the object, and the printing plate. From the rotational position detector that detects the rotational position of the cylinder, the compensator roller provided upstream of the printing plate cylinder, the detection value of the rotational position detector and the detection value of the register mark detector, the printing plate cylinder And a control unit for controlling the compensator roller so that the relative position between the rotational position of the register mark and the position of the register mark on the printing medium is set to a predetermined value.

[0007]

After the preprinting is completed, the preprinted object is set again in the printing device for additional printing. As a matter of course, the rotational position of the printing plate cylinder and the position of the pattern of the first printing are displaced when additional printing is performed. Therefore, the control unit first inputs the detection value of the register mark printed on the printing material and the detection value of the rotational position of the printing plate cylinder, and compares the position of the printing material and the rotational position of the printing plate cylinder. Find the difference value.

Next, the printing plate cylinder is separated from the printing impression cylinder, and the compensator roller is operated so that the relative difference value becomes a predetermined value such that preprinting and additional printing match. When the predetermined value is reached, the printing plate cylinder is pressed again against the printing impression cylinder to enable additional printing. As a result, there is no need to cut the print medium or loosen its tension.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of an embodiment of the present invention. In the figure, 1 is an unwinding portion for unwinding the printed material 3, 2 is an unwinding portion for winding the printed printing material 3, 4 is a drive gear cylinder, 5 is a printing impression cylinder, The two printing impression cylinders 5 are mechanically linked by one drive gear cylinder 4 and are rotationally driven synchronously.

6 is a printing plate cylinder provided for each printing impression cylinder, 7 is a compensator roller, 8 is a nip roller, and 9
Is a tension sensor for measuring the tension of the material 3 to be printed, 10 is a brake that holds the unwinding of the unwinding roller, 11 is an encoder that detects the rotational position of the printing plate cylinder, and 12 is printed on the material 3 to be printed. Scanning head for detecting register mark, 13 for compensator roller motor, 14 for tension sensor 9, encoder 11, scanning head
Enter the detection value from 12 and use the motor for the compensator roller.
A control unit for controlling 13.

Next, the operation will be described. Encoder 11
Rotate in a one-to-one correspondence with the printing plate cylinder 6,
Generates B and Z phase pulses. A and B phases per rotation
1000 pulses are generated, and the phases of both are 90 ° apart. this
It is possible to detect the forward rotation and the reverse rotation of the printing plate cylinder 6 by the shift of 90 °. The Z phase generates one pulse per rotation. Further, the preprinted register mark is printed at a position of a certain size from the beginning of one pattern printed by the printing plate cylinder 6. That is, the register mark may be printed on the printing plate cylinder 6.

FIG. 2 shows a time chart of misregistration measurement. The pitch of the Z phase of (a) corresponds to one rotation of the printing plate cylinder, and the pulse generated by the A and B phases of (b) during this period is
It occurs 1000 times. The gate signal (c) is for facilitating detection of the register mark by the scanning head 12. That is, the noise is prevented from being mistakenly recognized as a register mark and detected. The gate signal is described in JP-B-62-58878 and JP-B-63-28758.

The register mark signal detected by the scanning head 12 becomes a binarized signal of (e) with a threshold value. (G) shows the number of clocks in the gate of the reference clock (f) with b pulse, and (h) shows the number of clocks from the rising of the gate signal to the rising of the binarized signal of (e) with a pulse. ..

As shown in FIG. 2, a gate signal (c) is generated around the register mark signal (d) (although it is equivalent to two pulses in the figure, it may be any size).
The control unit 14 recognizes the register mark signal (d) and automatically generates the gate signal (c). The control unit 14 sets the threshold value to an appropriate value (2/3 of the peak voltage in FIG. 2) with respect to the peak voltage of the register mark signal (d). Z
The number of pulses from the phase (a) to the rising of the gate signal (c) is N, and the number of pulses from the falling is N + 2. The reference clock number from the rising edge of the gate to the register mark signal (d) is a, and the reference clock number of the gate signal (c) is b.

The number of pulses from the Z phase to the register mark signal is expressed by the following equation. N + ((N + 2) -N) * a / b (1)

Let L be the length of the pattern to be printed, that is, the repeat length (length of the printing plate cylinder), and convert equation (1) into the length. L0 = (N + ((N + 2) -N) * a / b) * L / 1000 (2)

Assuming that the register mark position of the previous printing is L1 from the beginning of the print pattern, consider the following equation. L2 = L0-L1 (3)

When the Z phase coincides with the print start of the printing plate cylinder (6), the expression (3) is a misregistration between the first printing and the additional printing. When the Z phase and the print head do not match, the shift amount is represented by ΔL and is set as an offset value, and the value obtained by subtracting ΔL from the equation (3) is the misregistration. This offset value does not change much after that, if it is measured when the printing apparatus is installed in the factory. In general, the Z phase does not coincide with the beginning of printing, so the following formula is used as the misregistration measurement value L3. L3 = L2-ΔL = L0−L1−ΔL (4)

When the pre-printing is completed, a raw fabric winding roll, which winds up the pre-printed printing medium 3 is attached to the raw fabric unwinding section 1, the printing medium 3 is set as shown in FIG. Operate to obtain equation (4). However, in this state, the phases of the first printing and the additional printing do not match. Therefore, the apparatus is first stopped, the printing plate cylinder 6 is separated from the printing impression cylinder 5, and the restraint of the printing medium 3 during this period is released.

Next, the control unit 14 controls the compensator roller motor 13 so that the value of L3 becomes zero. In FIG. 1, the nip roller 8 restrains the unrolled side of the material 3 to be printed and tension is applied to the unrolled side. By moving the floating roller of the compensator roller 7 up and down, the relative relationship between the rotational position of the stationary printing plate cylinder 6 and the register mark printed on the printing medium 3 moved by the floating roller can be adjusted. it can.

After the misregistration amount is preset by the compensator roller 7 as described above, the printing plate cylinder 6 is pressed against the printing impression cylinder 5 to be in a printing state and additional printing is performed.

FIG. 3 shows a flow chart in which the rotational position of the printing plate cylinder is adjusted to the previous printing when the additional printing is started. First, the pre-printing is completed, and the pre-printed original web winding roll is set in the original web unwinding device as shown in FIG. It is checked whether the machine speed of the device is below the low speed limit (step 30), and if it is below, a preset command is issued which is an operation for aligning the additional printing (head alignment of the print image) (step 31). If it is not below the low speed limit, check whether or not a preset command has already been issued (step 32) .If not, this state is because head alignment has already been completed and the printer is in the additional printing state. Perform additional printing control (step 33).

When the preset command is issued, it is checked whether the preset operation flag is ON (step 34),
If the flag is ON, the process proceeds to step 39. If the flag is not ON, it is checked whether the registration error measurement shown in the equation (4) is completed (step 35). If it is completed, the printing plate cylinder 6 is separated from the printing impression cylinder 5. To turn off the printing pressure (step 36). Next, the compensator roller motor 13 is controlled to start presetting (step 37), and the flag indicating that presetting is in progress is turned on.
(Step 38).

Next, it is checked whether or not the preset operation is completed (step 39). If it is completed, the preset operation flag is set to OF.
Setting to F (step 40), the printing plate cylinder 6 is pressed against the printing impression cylinder 5 to set the printing pressure to a predetermined pressure (step 41), the preset command is turned off (step 42), and the process is ended.

In the conventional apparatus shown in FIG. 4, when the number of colors that can be printed by the apparatus at one time (two colors in FIG. 4), the printing impression cylinder 20 is used.
Is common, there is an advantage that the misregistration between these two colors does not occur. However, if an attempt is made to perform additional printing with this apparatus, it is necessary to cut the material 3 to be printed, adjust the misregistration, and then join them together, as described above. Therefore, it is conceivable to attach a compensator roller to the apparatus shown in FIG. 4, but the range in which the printing medium 3 is in close contact with the printing impression cylinder 20 is large.
There are many contact surfaces, and even if a compensator roller or the like is used, it is not effective. INDUSTRIAL APPLICABILITY The present invention effectively utilizes the synchronous drivability of each printing plate cylinder by the printing impression cylinder of the prior art, reduces the contact area between the printing impression cylinder and the printing medium, and operates the compensator roller effectively. It is the one.

[0026]

As is apparent from the above description, according to the present invention, the initial adjustment of additional printing is performed by the control unit by synchronizing the printing impression cylinder with a common drive gear and effectively using the compensator roller. In addition, it is not necessary to cut the printed material for initial alignment, and it is also possible to prevent the occurrence of waste paper that occurs due to recovery of the tension decrease of the printed material due to the cutting.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an exemplary embodiment of the present invention.

FIG. 2 is a registration timing chart of the present embodiment.

FIG. 3 is a registration flow chart at the start of additional printing according to the present exemplary embodiment.

FIG. 4 is a diagram showing an example of a conventional rotary printing apparatus.

[Explanation of symbols]

 1 unwinding part 2 unrolling part 3 printed material 4 driving gear cylinder 5 printing impression cylinder 6 printing plate cylinder 7 compensator roller 8 nip roller 9 tension sensor 10 brake 11 encoder 12 scanning head 13 motor for compensator roller 14 control Department

Claims (1)

[Claims] 1. A drive cylinder, a plurality of printing impression cylinders driven by the driving cylinder, a printing plate cylinder provided in pair with each of the printing impression cylinders, and between the printing plate cylinder and the printing impression cylinder. A printing medium conveyed while being printed by the printing plate cylinder, a register mark detector for detecting a register mark printed on the printing plate, and a rotational position detector for detecting a rotational position of the printing plate cylinder. And a compensator roller provided upstream of the printing plate cylinder, and the rotational position of the printing plate cylinder and the printed mark of the register mark from the detection value of the rotational position detector and the detection value of the register mark detector. A rotary overprint printing apparatus, comprising: a controller that calculates a relative position with respect to a position on the body and controls the compensator roller so that the relative position becomes a predetermined value.