JP2737526B2 - Rotary printing press - Google Patents

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 in a plurality of colors, first, a sheet on which several colors have been printed is set in a printing apparatus again, 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 printing medium 3 unwound from the raw material unwinding unit 1 is wound around a printing impression cylinder 20, and the printing medium 3 is arranged on the circumference of the printing impression cylinder 20. Printing is performed by the printing plate cylinder 21 that is driven to rotate. In FIG. 4, one printing impression cylinder 20 is provided with two printing plate cylinders 21 driven by the two printing plate cylinders.
Since the two printing plate cylinders 21 are mechanically connected and rotated by a common printing impression cylinder 20, the two printing plate cylinders 21 rotate synchronously.

When four-color printing is performed by the above-described apparatus, first, two-color printing is performed.
After printing the colors on the two printing plate cylinders 21, the printing material is wound up by the material web take-up unit 2, set on the material web unwinding unit 1, and the remaining two colors are printed on the printing plate cylinder 21 again. This is called additional printing. When performing additional printing, the previous printing (this is called first printing)
Unless additional printing is performed at the same position as above, color misregistration occurs. For this reason, conventionally, as shown in FIG. 4, the printing medium 3 to be subjected to additional printing is once set in a printing apparatus, and then the printing medium 3 is cut to adjust the position of the printing plate cylinder 21 to the first printing. Preprint and printing plate cylinder
After correcting the displacement of 21 (this is called misregistration), and then reconnecting, additional printing was performed.

[0004]

However, in order to correct the misregistration in this manner, it is time-consuming and time-consuming to cut the printing medium 3 and reconnect it after the correction. Then, the tension of the printing medium 3 applied to the printing apparatus becomes zero, and printing performed until the tension is increased to a predetermined value must be discarded, resulting in an increase in waste paper.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described problems, and has as its object to provide a rotary press printing apparatus which can easily perform initial setting at the time of additional printing.

[0006]

In order to achieve the above object, a gear driving cylinder, a plurality of printing impression cylinders driven by the gear driving cylinder, and a printing plate cylinder provided for each of the printing impression cylinders are provided. A register mark detector for detecting a register mark pre-printed on a printing medium conveyed while being printed between the printing plate cylinder and the printing impression cylinder; and a rotation detecting a rotational position of the printing plate cylinder. A position detector, a compensator roller provided upstream of the printing plate cylinder, and the rotational position of the printing plate cylinder and the register mark from the detected value of the rotational position detector and the detected value of the register mark detector. the calculated relative difference value between the position on the printing material, and a control unit for controlling the compensator rollers to the relative difference value to a predetermined value, when printing after previous printing is finished, the control unit Before
After calculating the relative difference value, the printing plate cylinder is separated from the printing impression cylinder,
The control unit controls the compensator roller to determine the relative difference value.
After pressing the printing plate cylinder against the printing impression cylinder again,
Perform printing.

[0007]

After the first printing has been completed, the printing medium that has been preprinted again for additional printing is set in the printing apparatus. As a matter of course, the rotational position of the printing plate cylinder and the position of the pattern of the first printing are shifted when performing additional printing. Therefore, the control unit first inputs the detection value of the register mark printed on the printing medium and the detection value of the rotation position of the printing plate cylinder, and determines the relative position between the position of the printing material and the rotation 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 the first printing and the additional printing coincide. When the predetermined value is reached, the printing plate cylinder is pressed against the printing impression cylinder again to enable additional printing. Thus, there is no need to cut the printing medium or loosen the 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 FIG. 1, reference numeral 1 denotes a raw material unwinding unit for unwinding the printing medium 3, 2 denotes a raw material winding unit for winding the printed printing medium 3, 4 denotes a driving gear cylinder, and 5 denotes a printing impression cylinder. The two printing impression cylinders 5 are mechanically connected by one drive gear cylinder 4 and are synchronously driven to rotate.

Reference numeral 6 denotes a printing plate cylinder provided for each printing impression cylinder, 7 a compensator roller, 8 a nip roller, 9
Is a tension sensor for measuring the tension of the printing medium 3, 10 is a brake for holding down the unwinding of the raw material unwinding roller, 11 is an encoder for detecting the rotational position of the printing plate cylinder, and 12 is printed on the printing medium 3. Scanning head for detecting register mark, 13 for compensator roller motor, 14 for tension sensor 9, encoder 11, scanning head
Input the detection value from 12 and set the motor for compensator roller.
13 is a control unit for controlling

Next, the operation will be described. Encoder 11
Are rotated in a one-to-one correspondence with the printing plate cylinder 6, and A,
Generates B and Z phase pulses. A and B phases per rotation
1000 pulses are generated, and their phases are shifted by 90 °. this
The forward rotation and the reverse rotation of the printing plate cylinder 6 can be detected by the shift of 90 °. The Z phase generates one pulse per rotation. The preprinted register mark is printed at a position of a certain size from the head of one picture 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 the misregistration measurement. The pitch of the Z phase in (a) corresponds to one rotation of the printing plate cylinder, during which the pulse generated by the A and B phases in (b)
Occurs 1000 times. The gate signal (c) is for facilitating detection of the register mark by the scanning head 12. That is, it is possible to prevent noise from being erroneously 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 binary signal (e) with a threshold value. (G) is a b pulse and indicates the number of clocks in the gate of the reference clock (f). (H) is an a pulse and indicates the number of clocks from the rise of the gate signal to the rise of the binarized signal of (e). .

As shown in FIG. 2, a gate signal (c) is generated around the register mark signal (d) (corresponding to two pulses in the figure, but may have any magnitude).
The controller 14 recognizes the register mark signal (d) and automatically generates the gate signal (c). The threshold value is set by the control unit 14 to an appropriate value (2/3 of the peak voltage in FIG. 2) for the peak voltage of the register mark signal (d). Z
The number of pulses from the phase (a) to the rise of the gate signal (c) is N, and the number of pulses from the phase (a) to the fall is N + 2. The reference clock number from the gate rising 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 represented by the following equation. N + ((N + 2) -N) * a / b (1)

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

Assuming that the register mark position of the first printing is located at L1 from the head of the printed picture, the following equation is considered. L2 = L0-L1 (3)

When the Z phase coincides with the printing start of the printing plate cylinder (6), the expression (3) is misregistered between the first printing and the additional printing. When the Z phase does not coincide with the print head, the shift amount is represented by ΔL, which is set as an offset value, and a value obtained by subtracting ΔL from Expression (3) becomes a register shift. If this offset value is measured when the printing apparatus is installed in a factory, it will not change much thereafter. In general, since the Z phase does not coincide with the head of printing, the following equation is used as the measured misregistration value L3. L3 = L2−ΔL = L0−L1−ΔL (4)

When the pre-printing is completed, a web take-up roll on which the pre-printed printing medium 3 is wound is attached to the web unwinding unit 1, the printing medium 3 is set as shown in FIG. Operates 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 constraint on 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 material unwinding side of the printing medium 3 and applies tension to the material winding side. By moving the idler roller of the compensator roller 7 up and down, it is possible to adjust 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 idler roller. 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 make a printing state, and additional printing is performed.

FIG. 3 shows a flowchart for adjusting the rotational position of the printing plate cylinder to the first printing when starting additional printing. First, the pre-printing is completed, and the apparatus is operated in a state where the pre-printed web take-up roll is set on the web unwinder as shown in FIG. A check is made to see if the machine speed of the apparatus has fallen below the low speed limit (step 30). If the machine speed falls below the limit, a preset command is issued (step 31), which is an operation for performing additional printing positioning (print image head positioning). If the speed is not below the low speed limit, it is checked whether a preset command has already been issued (step 32) .If not, this state indicates that the head alignment has already been completed and the additional printing state has been entered. Additional printing control is performed (step 33).

When the preset command is issued, it is checked whether or not 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 misregistration measurement shown in equation (4) is completed (step 35). If completed, the printing plate cylinder 6 is separated from the printing impression cylinder 5. Then, the printing pressure is turned off (step 36). Next, presetting is started by controlling the compensator roller motor 13 (step 37), and the flag indicating that the preset operation is being performed is turned on.
(Step 38).

Next, it is determined whether or not the preset operation has been completed (step 39).
Then, 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 ends.

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.
Are common, there is an advantage that the misregistration between the two colors does not occur. However, in order to perform additional printing with this apparatus, it is necessary to cut the printing medium 3 as described above, adjust the misregistration, and then join them. Therefore, it is conceivable to attach a compensator roller to the apparatus shown in FIG. 4. However, since 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 using a compensator roller or the like has no effect. The present invention effectively utilizes the synchronous driveability 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 was made.

[0026]

As apparent from the above description, the invention, by synchronizing the printing impression cylinder by a common driving gear
By using the compensator roller effectively by minimizing the deviation between the printing plate cylinders , the control unit performs the initial alignment of additional printing, so there is no need to cut the printing medium and perform the initial alignment. This can also prevent the occurrence of waste paper that occurs to recover from the decrease in the tension of the printing medium due to the above. In addition, the printing plate cylinder is marked during initial
The substrate is released from the printing cylinder by pulling it away from the impression cylinder
Initial setting can be performed in a short time, and
Can be reduced.

[Brief description of the drawings]

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

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

FIG. 3 is a register registration flowchart at the start of additional printing in the present embodiment.

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Material unwinding part 2 Material unwinding part 3 Printed material 4 Drive 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

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-43051 (JP, A) JP-A-1-99846 (JP, A)

Claims (1)

(57) [Claims] 1. A gear driving cylinder, a plurality of printing impression cylinders driven by the gear driving cylinder, a printing plate cylinder provided in a pair with each printing impression cylinder, the printing plate cylinder and the printing impression cylinder A register mark detector for detecting a register mark pre-printed on a printing medium conveyed while being printed between, a rotation position detector for detecting a rotation position of the printing plate cylinder, and an upstream of the printing plate cylinder. A compensator roller, and a relative difference between the rotational position of the printing plate cylinder and the position of the register mark on the printing medium from the detected value of the rotational position detector and the detected value of the register mark detector. calculating a value, and a control unit for controlling the compensator rollers to the relative difference value to a predetermined value, when printing after previous printing is completed,
After the control unit calculates the relative difference value, the printing plate cylinder is moved to the printing impression cylinder.
The control unit controls the compensator roller.
After setting the relative difference value to a predetermined value, the printing plate cylinder is
And a post-printing press .