JPH0378067B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an apparatus for managing the print quality of web-like printed matter.

[Prior art and its problems]

2. Description of the Related Art A rotary printing press is known in which a web-shaped printing paper is sequentially fed out, the same pattern is repeatedly printed on the paper, and the paper is wound up again after printing is completed. Such printing presses are equipped with means for monitoring printing conditions such as off-printing and misregistration in each printing unit, and a rotary encoder is installed on the printing press to measure the length of the printing paper as it travels. For example, it is installed immediately after the final printing unit, and print condition fluctuation data obtained by this monitoring means is aggregated and stored as print quality data together with position information from the rotary encoder, and is stored during the rewind inspection process of rolled printed matter. For example, it is possible to check printed matter based on the print quality data that is available.
This is proposed in Publication No. 224754.

Here, since the rotary encoder that generates position information and the monitoring means that collect print condition fluctuation data are installed at different locations, the path length between the installation position of the rotary encoder and the installation position of each monitoring means is determined, and the position information is calculated. It is necessary to correct the position of the print quality data on the printing paper.

In general, the path length between printing units of a printing press (the length of the path the printing paper passes through) differs depending on the product type, so determining this path length every time the print quality is changed is a very time-consuming task. I was getting used to it.

[Purpose of the invention]

Therefore, an object of the present invention is to provide a print quality control device that can easily determine the path length for correcting the position information of print state variation data.

[Summary of the invention]

The present invention, which has been made to achieve the above object, is installed in a printing machine that repeatedly prints the same pattern by feeding out a web-shaped printing paper and passing it through a plurality of printing units. a measuring means for measuring the length of the printing paper as it walks; and a means for obtaining positional information on the printing paper of the printing state fluctuation data obtained by the monitoring means from the measuring means. A printing quality control device, wherein a metal piece is attached to the printing paper before printing starts, and a detector for detecting the metal piece is installed in each printing unit,
Means for determining the web path length of the printing press from the timing signal obtained from the detector when the metal piece passes through each detector and the length data from the measuring means is provided, and further the printing condition is changed based on the determined web path length. The present invention is a print quality control device characterized by comprising means for correcting position information of data.

〔Example〕

The present invention will be explained in detail below based on embodiments of the drawings.

FIG. 1 is a schematic explanatory diagram of a state in which the printing quality control device of the present invention is attached to a printing press.

In FIG. 1, a web of printing paper 2 that is continuously unwound from an unwinding reel 1 is printed in each printing unit 11 ₁ , 11 ₂ , 11 ₃ , . . . 11 _o of a printing machine 10, and then wound up again. It is wound onto reel 3. Each printing unit has a monitoring means 12 ₁ for monitoring printing quality such as printing defects including off-printing and misregistration.
12 ₂ , . . . 12 _o are provided, and it is possible to detect deprinting, misregistration, etc. occurring in each printing unit as printing state fluctuation data. Since such monitoring means is already known, a detailed explanation thereof will be omitted.

Further, a rotary encoder 14 is provided which outputs a pulse according to the length of the printed matter running immediately after the final printing unit 11 _o , and the respective monitoring means 12 ₁ , 12 ₂ , . . . , 12 _o and the rotary encoder 14 is connected to an arithmetic and control unit 20.

In addition, each printing unit 11 ₁ , 11 ₂ , ..., 1
Metal detectors 13 ₁ , 13 ₂ , ..., 13 _o are provided at 1 _o , and a metal detector 15 is also provided at the rotary encoder 14 installation position,
Each is connected to an arithmetic and control unit 20, and detects the passage of a metal piece stuck to the printing paper 2 to detect the web path length.

FIG. 2 shows the configuration of the arithmetic and control unit 20.

Each monitoring means 12 ₁ , 12 ₂ , ..., 12 _o is connected to the bus line via an interface 27 and each detector 13 ₁ , 13 ₂ , ..., 13 _o ,
15 is connected to the bus line via an interface 28. Further, the rotary encoder 14 is connected to a frequency dividing circuit 24, and adjusts the frequency dividing circuit 24 so that, for example, one pulse signal is output for every 1 m of printing paper. The counter 25 counts the pulses from the frequency dividing circuit 24,
The length of the printing paper can be determined from this count number.

In addition, the bus line includes CPU21, ROM22,
A RAM 23 is connected to the CPU 21 according to the processing program stored in the ROM 22, which takes in data from each monitoring means, each detector, and a counter 25, performs arithmetic processing, and transfers the results to the RAM 23.
23.

That is, each printing unit 11 ₁ , 11 ₂ , ..., 1
When data regarding the printing status is input from the monitoring _means 12 ₁ , _{12 2} , . The length from a certain reference point) is read in, and print quality data, which is a set of each item of print state variation data, print unit number, and position information, is sequentially stored in a predetermined area of the RAM 23.

However, as described above, since the rotary encoder 14 for obtaining the position information and the monitoring means 12 ₁ , 12 ₂ , . . . , 12 _o for detecting the printing state are installed at different positions, The position information actually has an error equal to the path length between the rotary encoder 14 and each monitoring means.

This error reaches a maximum of 30m to 50m, so if print quality data is used in subsequent processes without correcting this error, the error will be too large.
It is impossible to make effective use of it.

For this purpose, a piece of metal such as aluminum or a metal tape is attached to the printing paper before printing starts, and the printing paper is passed along a set path. Experiments have confirmed that metal pieces with a thickness of about 50 μm or less will not damage the printing cylinder.

As shown in Figure 3, when a printing paper with a metal piece pasted on it is passed through the printing unit,
The CPU 21 has each detector 13 ₁ , 13 ₂ , ..., 13 _o
Check whether a metal piece has been detected (steps S1 and S2), and if a metal piece is detected,
The number of the printing unit in which the detector is installed and the value of the counter 25 at that time are read as a pair (step S2). Normally, metal pieces are detected in the order of detector ₁₃₁ to detector _13o , and finally the metal piece is detected by detector 15, and in all cases, the printing unit number (original point for detector 15) is The value of the counter 25 at the time of detection is read as a pair.

When metal pieces are detected by all the detectors (n+1 pieces) (step S4), the difference between the read count value of each printing unit and the count value of the detector 15 is calculated, and the origin (rotary encoder The path length from the installation position) to each printing unit is determined (step S6). Each determined path length is recorded along with the print unit number as a correction value.
It is stored in a predetermined area of the RAM 23.

After printing is completed, as shown in Figure 4, the RAM
23 (step S1), and recognizes the print unit number of the read print quality data (step S1).
2).

Next, the correction value of the print unit number is read out (step S3), and a difference calculation is performed with the position information of the print quality data to correct the position information (step S4). By performing such processing on all print quality data (step S5),
Errors corresponding to the path length from the rotary encoder to each printing unit in the position information of the printing state variation data are corrected, and accurate positions can be specified.

Note that the above explanation describes an example in which position information correction calculations are performed all at once after printing is completed, but since correction values are obtained before printing starts, correction calculations can be performed at the same time as printing quality data is imported. It's okay.

Further, although an example has been shown in which data processing is performed using software, similar processing can be performed by configuring an electric circuit using hardware.

Further, the installation position of the rotary encoder is not limited to immediately after the final printing unit, but can be installed at any position on the printing press as long as the intended purpose can be achieved.

〔Effect of the invention〕

The present invention has the above-described configuration, and it is possible to easily correct the positional information of the printing state fluctuation data, thereby obtaining accurate positional information without any errors, and therefore, it is possible to easily correct the positional information of the printing state fluctuation data. It is possible to stop the feeding of printed matter at an accurate position during inspection at a return machine, etc., greatly improving work efficiency.

In addition, in order to obtain a correction value for position information, a metal piece is pasted on the printing paper and this is detected by a metal sensor, so an identification mark is marked and this is read optically to obtain the correction value. Compared to the above, there is no difficulty in distinguishing the printed pattern from the printed pattern, and correction values can be obtained accurately.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of the print quality control apparatus of the present invention, FIG. 2 is a block diagram of the arithmetic and control unit, and FIGS. 3 and 4 are flowcharts of the processing of the CPU. 11 ₁ , 11 ₂ , ..., 11 _o ... printing unit,
12 ₁ , 12 ₂ , ..., 12 _o ... monitoring means, 13 ₁ ,
13 ₂ ,..., 13 _o , 15...detector, 20... arithmetic control unit.

Claims (1)

[Claims] 1 Installed in a rotary printing machine that prints a predetermined pattern by unwinding a web-shaped printing paper and passing it through multiple printing units, and winding it up after printing is completed.
A monitoring means installed in each printing unit to monitor the print quality, a measuring means to measure the length of the printing paper as it travels, and position information on the printing paper of print condition fluctuation data obtained by the monitoring means. In the printing quality control device, a metal piece is attached to the printing paper before printing starts, a detector for detecting the metal piece is installed in each of the printing units, and a metal piece is obtained from the detector. means for determining the web path length of the printing press from the timing signal when the metal piece passing through each detector and the length data from the measuring means; 1. A printing quality control device comprising: means for correcting.