JP7316917B2 - Printer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a printing press that performs trial printing before final printing.

In such a printing machine, a predetermined number of printed sheets are printed as test prints to check the density (match the density) before the actual printing. Specifically, printing of a predetermined number of sheets is performed as test printing, the density of the test printed matter is measured, and it is determined whether the measured density value is within an allowable range with respect to the target density value. If it is determined to be within the allowable range, the printer shifts to production printing without stopping printing. While performing the correction, test printing is also performed to check the density (density adjustment) (for example, Japanese Patent Application Laid-Open No. 2002-200013). The printed matter of the trial printing becomes waste paper.

As described above, if the measured density values are within the acceptable range, production printing is immediately started. Even after the shift to production printing, the density status of the printed matter is monitored, and feedback is provided as necessary, but the measured density value may fall outside the allowable range. A printed matter whose density value is out of the allowable range during final printing becomes waste paper.

JP 2013-75518 A

One of the reasons why the measured density value is out of the allowable range is that when the density is measured before the density converges (stabilizes) (including the printed material in the process of density hunting (overshoot or undershoot)). This is because the transition to production printing is determined based on the results of the inspection. Also, this is likely to occur when the number of test prints is relatively small. Therefore, this problem can be solved by measuring the density of the printed matter after the density converges (the density stabilizes). A large number of trial prints are required before the process is completed, and all the trial printed materials are treated as wasted paper, resulting in a large amount of wasted paper.

SUMMARY OF THE INVENTION The present invention has been made to solve such problems, and provides a printing press that suppresses the increase in wasted paper during trial printing and prevents density values measured after the shift to final printing from falling outside the allowable range. to provide.

In order to achieve the above object, the printing press according to the present invention includes density value measuring means for measuring the density value of the test printed material being conveyed, and the test printed material based on the density value measured by the density value measuring means. a pass/fail judgment means for judging whether or not the print is acceptable; The means is characterized in that a plurality of consecutive pass judgments by the pass/fail judging means is configured as a condition for judging that the shift to final printing is possible.

According to the above configuration, it is possible to determine that there is a high possibility that the density has converged (stable) to the extent that there is no problem when the pass judgment by the pass/fail judging means continues a plurality of times. Therefore, if the production printing is started on the condition that the pass judgment is made several times in a row, the density value measured after the production printing will be out of the allowable range while the required minimum amount of wasted paper is kept in the trial printing. can be prevented.

Further, in the printing press according to the present invention, the density value measuring means measures the density value of each of a plurality of solid patches printed in a range corresponding to each ink fountain key of the test printed matter, and the density values of the plurality of solid patches are measured. A density-related index deriving means for deriving, as a density-related index, the number of solid patches whose measured density value is within the target density value, and the pass/fail judging means derives the density-related index deriving means. If the density-related index is equal to or greater than the target number, which is the target index, the test printed material is determined to be acceptable, and the density-related index derived by the density-related index deriving means is less than the target number. Alternatively, it may be a means for judging that the test print is unacceptable.

As described above, when the number of solid patches derived by the density-related index derivation means is equal to or greater than the target number, the pass/fail determination means determines that the test printed material is acceptable, and the density-related index derivation means If the derived number of solid patches is less than the target number, it is determined that the test printed matter is rejected.

Further, in the printing press according to the present invention, the density value measuring means measures the density value of each of a plurality of solid patches printed in a range corresponding to each ink fountain key of the test printed matter. a density-related index deriving means for deriving, as a density-related index, an average density value obtained by dividing a total density value obtained by summing the density values of solid patches by the number of solid patches; If the difference between the derived average density value and the target density value, which is the target index, is within a set range, it is determined that the test printed matter is acceptable, and the average density value derived by the density-related index derivation means. and the target density value is outside the set range, it may be determined that the test printed matter is rejected. In deriving the average density value, if there is a range corresponding to an ink fountain key that does not have images other than solid patches, the solid patches in that range can be excluded from the targets for deriving the average density value.

As described above, the pass/fail determination means determines that the test printed material is acceptable when the difference between the average density value derived by the density-related index derivation means and the target density value is within the set range. If the difference between the average density value derived by the density-related index deriving means and the target density value is outside the set range, it is determined that the test printed material is rejected.

According to the present invention, the density value measured after the shift to the final printing while suppressing an increase in wasted paper during the test printing is provided with the transition means for shifting to the final printing when the pass judgment is made consecutively a plurality of times. It is possible to provide a printing press that prevents the from falling outside the allowable range.

1 is a side view of a printing press; FIG. 3 is a block diagram showing the control configuration of the printing press; FIG. 10 is a flowchart for performing test printing OK determination processing of the printing machine, and shows the first processing. FIG. 4 is a flow chart for performing test printing OK determination processing of the printing machine, and shows the processing continued from FIG. 3 ; FIG. FIG. 5 is a flowchart for performing trial printing OK determination processing of the printing machine, and shows the processing continued from FIG. 4 ; FIG.

A printer according to an embodiment of the present invention will be described below with reference to the drawings.

The printing machine 1 includes a paper stacking table 2, a paper feeding unit 4 for feeding printing papers one by one from the paper stacking table 2 by a feeder device 3, and printing paper fed from the paper feeding unit 4 in five colors ( A printing unit 5 for printing colors including at least one spot color), and a range corresponding to each ink fountain key (sometimes simply called a key) on printing paper (printed matter) printed by the printing unit 5. An RGB camera 6 which is an RGB imaging means for imaging a plurality of solid patches (not shown) printed on the printer, and a paper ejection unit 7 for conveying and ejecting the printed paper after imaging. there is In FIG. 1, the paper stacking table 2 side is the front side, the paper discharge section 7 side is the rear side, and the direction passing through the paper surface is the left-right direction (or width direction).

The printing unit 5 includes four printing units 5A, 5B, 5C, and 5D for printing C (cyan), M (magenta), Y (yellow), and K (black), which are the four process colors. and a printing unit 5E for printing a spot color, which is a color. In this embodiment, the printing unit 5E for printing the spot color is arranged at the trailing end, but it may be arranged at any position. The printing unit 5A corresponds to the unit 1 appearing in the flow chart described later, the printing unit 5B corresponds to the unit 2 appearing in the flow chart to be described later, and the printing unit 5C corresponds to the unit 3 appearing in the flow chart to be described later. The printing unit 5D corresponds to the unit 4 appearing in the flowcharts described later, and the printing unit 5E corresponds to the unit n appearing in the flowcharts described later.

The RGB camera 6 is accommodated in a box 9 arranged at the front end side upper part of the paper discharge section 7, and is placed between the printing unit 5E located at the rear end and the paper discharge section 7 at step 10. A plurality of solid patches of printing paper conveyed through a formed opening (not shown) are imaged. The opening can be switched between an open state and a closed state by a lid (not shown) that can be opened and closed. In addition, when crossing the step 10 for the purpose of inspection or troubleshooting, an RGB camera is attached to each of the pair of side walls 11, 11 (only one side is shown in FIG. 1) provided in the lateral direction of the paper discharge section 7. A push button 12 is provided for temporarily interrupting and resuming imaging by 6 . By pressing the push button 12, the image taking by the RGB camera 6 is interrupted, and by pressing the push button 12 again, the image taking by the RGB camera 6 is resumed. The push button 12 can also be provided on the rear wall portion of the paper ejection section 7 . Further, when the work is interrupted, the push button 12 flashes to notify the operator of the interruption. A line sensor camera, a CMOS camera, a CCD camera, and the like can be used as the RGB camera 6, which is an imaging means. Image data of each solid patch imaged by the RGB camera 6 is input to the density value calculation means 13 provided in the control section S shown in FIG. 2, and the density value calculation means 13 calculates the density value of each solid patch. The RGB camera 6 and the density value calculation means 13 constitute a density value measurement means 14 (see FIG. 2) for measuring the density values of a plurality of solid patches. If the printing press 1 is configured as a reversing machine having a reversing device between the printing units, the RGB camera 6 is also provided at the position where the reversing device is arranged so that the pre-printed surface (the surface to be printed before reversing) ) can also be imaged.

FIG. 2 shows a block diagram for performing test printing OK determination processing of the printing machine of the present invention. That is, the printing press includes a control section S to which image data from the RGB camera 6 is input. An index derivation unit 15 , a pass/fail determination unit 16 , and a final printing transfer unit 17 are provided.

The density value calculation means 13 is a means for calculating the density value of each solid patch based on the imaging data of each solid patch imaged by the RGB camera 6, as described above. It is also possible to use density values obtained by converting the calculated three RGB solid density values into CMYK solid density values.

The density-related index deriving means 15 is a means for deriving the number of solid patches within the target density value among the density values of a plurality of solid patches as a density-related index. For example, if the target density value is a density value having a predetermined range, and the density value is set to, for example, 1.4 to 1.6, the measured density value is 1.4 to 1.6. 1.6 to derive the number of solid patches. The setting of the target density value can be freely changed, for example, for each color or according to the work to be printed.

The pass/fail judgment means 16 is a means for judging pass/fail of the test printed material based on the density-related index derived by the density-related index deriving means 15 and the target index. Specifically, when the number of solid patches derived by the density-related index derivation unit 15 is equal to or greater than the target number, which is the target index, the test printed matter is determined to be acceptable, and the density-related index is determined to be acceptable. If the number of solid patches derived by the deriving means 15 is less than the target number, it is determined that the test printed matter is rejected. For example, when the total number of solid patches is 21 (when there are 21 ink fountain keys), the total number of 21 may be the target number, or any number less than or equal to 20 may be used. The number of targets can vary for each color and depending on the job to be printed. Also, if there is a range corresponding to an ink fountain key that has no image other than solid patches, the number of solid patches in that range may not be added to the total number of solid patches or the number of solid patches included in the target density value. If this addition is not performed, the target number, which is the target index for pass/fail determination by the pass/fail determination unit 16, will be a number calculated from the set pass rate (equivalent to the production printing transition OK %, which will be described later). .

The final printing transition means 17 can select one pass judgment by the pass/fail judging means 16 or a plurality of consecutive pass judgments as a condition for shifting from test printing to final printing. Also, the number of times of multiple times can be set to an arbitrary number of 2 or more.

If the pass judgment by the pass/fail judging means 16 continues a plurality of times (twice or more), it can be judged that there is a high possibility that the density has converged (stabilized) to the extent that there is no problem. Therefore, if the production printing is started on the condition that the pass judgment has been made several times (two or more times) in succession, the density value measured after the production printing is reduced while reducing the required minimum waste paper in the trial printing. It is possible to prevent it from going out of the allowable range.

Further, the production printing shift means 17 can select one pass judgment by the pass/fail judgment means as a condition for shifting from trial printing to final printing.

In this manner, since the production printing transition means 17 is configured to be able to select and set conditions for transitioning from various trial printings to final printings, suitable conditions can be accurately set according to the required quality level of the printed matter to be printed. can. In other words, in the case of a printed matter with a high required quality level regarding density, a succession of multiple (two or more) pass judgments is selected as the condition, and in the case of a printed matter with a low required quality level regarding density, the condition is set to pass. By selecting the determination once, it is possible to further reduce wasted paper and perform printing efficiently. The conditions may be set to arbitrary values by manual operation by the operator, or may be automatically selected and set by the control section S from job (JOB) information.

Next, the test printing OK determination process, which is the process of shifting from test printing to final printing, will be described based on the flowcharts shown in FIGS. 3 to 5. FIG. FIGS. 3 to 5 are a series of flowcharts for performing test printing OK determination processing, but since they cannot be described in one diagram, they are illustrated separately on three sheets.

First, make various settings. Specifically, the target density, the production printing transition OK%, and the production printing transition determination count are set (step S1). The target density is the target density value of a solid patch of each color, and the upper and lower limits of the allowable range are set, or the target value and the allowable deviation from the target value are set. The production printing shift OK% is the ratio (%) of the number of solid patches within the target density at which it is determined that production printing is possible, and is set for each unit (for each color). This OK% for production printing is a condition for the pass/fail judgment means 16 to judge pass/fail. The number of test printing transition determination times is a condition for judging that it is possible to shift from trial printing to final printing, and the number of trial printings determined to be at or above the final printing transition OK% is set for each unit (each color). The number of times is configured to select one of 1 time, 2 times in a row, and 3 times in a row. This number of times of transition to production printing is a condition for the production printing transition means 17 to determine that it is possible to shift from test printing to final printing.

Next, the number of trial printing density judgment sheets is set (step S2). The test printing density determination number of sheets is the number of printed sheets per test printing. In this embodiment, the default value is 30 sheets. Note that the test print density determination number can be set for each test print count. For example, it is possible to set the number of prints for the third test print to be less than the number of prints for the second test print. The density value of the solid patch at each position in the test printout is the density value of the last 10 sheets in the test printout of the test print density determination number, excluding the two minimum and maximum values. It is the average value of eight density values. However, the density value of the solid patch at each position in the test print is not limited to this. For example, the average value of the remaining three density values obtained by excluding the two minimum and maximum values from among the density values of the last five sheets may be used. Alternatively, it can be the density value of the last printed material among the test printed materials of the test printing density determination number. It is also possible to use the average value of the density values of the last three printed materials among the test printed materials of the test print density determination number. When the above settings are completed, m-th test printing (for example, the first time) is started (step S3).

It is determined whether or not the number of printed sheets for m-th (first) trial printing has reached the set number of m-th trial printing for density determination (number of m-th trial printing for density determination) (step S4). When it is determined that the number of printed sheets has reached the set density determination number for the m-th (first) trial print, the number of keys whose density value measured for the color printed in unit 1 falls within the target density is calculated (unit 1 (step S5). The number of keys is synonymous with the number of solid patches. Next, it is determined whether the calculated value of (the number of keys in unit 1 that have reached the target density)/(the number of all keys in unit 1) x 100% is equal to or greater than the set value of OK% for production printing. Determine (step S6). If the calculated value is equal to or greater than the set value of OK% for production printing, it is judged to be acceptable. It is determined whether or not the number of pass determinations has reached the set number of determinations for shift to production printing (one, two times in a row, or three times in a row) (step S7). If it is determined that the time has been reached, the production printing shift OK flag of unit 1 is set (step S8), and the process proceeds to the determination of unit 2 (step S9). If it is determined that it has not reached, the process proceeds to the determination of the unit 2 (step S9). Also, if it is determined in step S6 that the value is less than the set value of the shift OK% for production printing, the process proceeds to the determination of the unit 2 (step S9).

In step S9, the number of keys for which the density values measured for the colors printed by the unit 2 are within the target density is calculated (the number of OK keys for the m-th (first) trial printing of the unit 2 is calculated). ). Next, it is determined whether the calculated value of (the number of keys in unit 2 that have reached the target density)/(the number of all keys in unit 2) x 100% is equal to or greater than the set value of OK% for production printing. Determine (step S10). If the calculated value is equal to or greater than the set value of OK% for production printing, it is judged to be acceptable. It is determined whether or not the number of pass determinations has reached the set number of determinations for shift to production printing (one, two consecutive times, or three consecutive times) (step S11). If it is determined that the time has been reached, the production printing shift OK flag of unit 2 is set (step S12), and the process proceeds to the determination of unit 3 (step S13). If it is determined that it has not reached the limit, the process proceeds to the determination of the unit 3 (step S13). Also, if it is determined in step S10 that the value is less than the set value of the shift OK% for production printing, the process proceeds to the determination of the unit 3 (step S13). In step S13, the number of keys for which the density values measured for the colors printed by the unit 3 are within the target density is calculated (the number of OK keys for the m-th (first) trial printing of the unit 3 is calculated).

Next, it is determined whether or not the calculated value of (the number of keys in unit 3 that have reached the target density) ÷ (the number of all keys in unit 3) x 100% is equal to or greater than the set value of OK% for production printing. Determine (step S14). If the calculated value is equal to or greater than the set value of OK% for production printing, it is judged to be acceptable. It is determined whether or not the number of pass judgments has reached the set number of judgments for shifting to production printing (one, two consecutive times, or three consecutive times) (step S15). If it is determined that the time has been reached, the production printing shift OK flag of unit 3 is set (step S16), and the process proceeds to the determination of unit 4 (step S17). If it is determined that it has not reached, the process proceeds to the determination of the unit 4 (step S17). Further, if it is determined in step S14 that the value is less than the set value of the shift OK% for production printing, the process proceeds to the determination of the unit 4 (step S17). In step S17, the number of keys whose density value measured for the color printed by the unit 4 falls within the target density is calculated (the number of OK keys in the m-th (first) trial printing of the unit 4 is calculated). ).

Next, it is determined whether the calculated value of (the number of keys in unit 4 that have reached the target density) ÷ (the number of all keys in unit 4) x 100% is equal to or greater than the set value of OK% for production printing. Determine (step S18). If the calculated value is equal to or greater than the set value of OK% for production printing, it is judged to be acceptable. It is determined whether or not the number of pass determinations has reached the set number of determinations for shift to production printing (one, two times in a row, or three times in a row) (step S19). If it is determined that the time has been reached, the production printing shift OK flag of unit 4 is set (step S20), and the process proceeds to the determination of unit n (step S21). If it is determined that it has not reached, the process proceeds to the determination of unit n (step S21). Also, if it is determined in step S18 that the value is less than the set value of the shift OK% for production printing, the process proceeds to the determination of unit n (step S21). In step S21, the number of keys for which the density value measured for the color printed by unit n is within the target density is calculated (the number of OK keys for m-th (first) trial printing of unit n is calculated). ).

Next, it is determined whether the calculated value of (the number of keys in unit n that have entered the target density)/(the number of all keys in unit n) x 100% is equal to or greater than the set value of OK% for production printing. Determine (step S22). If the calculated value is equal to or greater than the set value of OK% for production printing, it is judged to be acceptable. It is determined whether or not the number of pass judgments has reached the set number of judgments for shifting to production printing (one, two consecutive times, or three consecutive times) (step S23). If it is determined that the time has been reached, the production printing shift OK flag of unit n is set (step S24), and the process proceeds to step S25. If it is determined that it has not reached, the process proceeds to step S25. If it is determined in step S22 that it is less than the set value of the shift OK% for production printing, the process proceeds to step S25. In step S25, it is determined whether or not the production printing transfer OK flag of all units is set. If it is determined that the production printing transition OK flags of all units are set, the production printing is shifted to (step S26). If it is determined that the production printing shift OK flags of all units are not set, the process returns to step S3 to start the m-th trial printing (if the previous printing was the first printing, then the second printing).

When printing only the front side (or only the back side) of the printing paper using the printing machine 1, the number of pass judgments for the densities of all the colors printed on the front side (or the back side) is the set production printing transition judgment. When it comes to the number of times, it will shift from test printing to final printing. In addition, when printing both the front and back sides of the printing paper using the printing machine 1, the number of pass judgments for the densities of all colors printed on both the front and back sides is set to the set production printing transition. When it reaches the number of determinations, the test printing is shifted to the final printing. Note that in the present embodiment, printing is continued from the start of test printing to the transition to final printing unless a problem such as a paper feed failure occurs.

Note that, for example, when the number of times to determine the transition to production printing is set to 2 consecutive times and printing is performed only by unit 1 and unit 2, in unit 1, the first and second test printings were continuously judged to be acceptable. In Unit 2, if the 3rd trial printing is judged to be unacceptable, and in Unit 2, the 1st trial printing is judged to be unacceptable, and the 2nd and 3rd trial printings after the 1st trial printing are judged to be unacceptable, Unit 1 and Since the flags are set in all units 2, production printing is started. In short, if the flags for all units (all colors) are set, the process proceeds to production printing. Note that in this embodiment, regardless of the number of times of trial printing, trial printing is performed until the set number of determinations to shift to production printing (one of one, two times in a row, or three times in a row) is reached. If the number of times of printing increases, control may be performed to automatically reduce the set number of times of transition to production printing. For example, when the production printing transition determination count is set to three consecutive times, if the production printing transition OK flags of all units (all colors) are not set by the time of test printing (that is, if production printing is not transitioned), After the sixth trial printing, the number of determinations to shift to final printing may be automatically reduced (for example, the setting may be changed to two consecutive times).

The density-related index derivation means 15 and final printing transition means 17 described in the above embodiment can also be configured as follows. That is, the density-related index deriving means 15 is composed of means for deriving the average density value obtained by dividing the total density value obtained by summing the density values of a plurality of solid patches by the number of solid patches, as the density-related index, and the production printing transfer means 17. but if the difference between the average density value derived by the density-related index deriving means 15 and the target density value, which is the target index, is within a set range, it is determined that the test printed material is acceptable, If the difference between the average density value derived by the density-related index deriving means 15 and the target density value is outside the set range, it may be determined that the test printed material is rejected.

It should be noted that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

In the above-described embodiment, a printing press having five units was shown, but the printing press may have one unit or any number of units (two or more). Also, in a printing machine having a plurality of units, printing may be performed using a smaller number of units (at least one unit or more) than the total number of units.

Also, in the above embodiment, the RGB camera 6 is used, but a spectrophotometer may be used. In this case, the spectrophotometer constitutes density value measuring means 14 for measuring density values of a plurality of solid patches.

Further, in the above-described embodiment, the density of all solid patches is checked, but it is also possible to check only the density of solid patches corresponding to areas important in terms of print quality.

DESCRIPTION OF SYMBOLS 1... Printing machine 2... Paper stacking stand 3... Feeder apparatus 4... Paper feeding part 5... Printing part 5A, 5B, 5C, 5D, 5E... Printing unit 6... RGB camera, 7... Paper discharge part 9 Box 10 Step 11 Side wall 12 Button 13 Density value calculation means 14 Density value measurement means 15 Density-related index calculation means 16 Pass/fail judgment means 17 Final printing Transfer means, S... control unit

Claims (3)

density value measuring means for measuring the density value of the test printed material being conveyed; pass/fail determination means for determining whether the test printed material passes or fails based on the density value measured by the density value measuring means; production printing transition means for determining whether or not to transition from test printing to final printing based on the pass/fail judgment by the pass/fail judgment means;
The printing machine according to claim 1, wherein the transition means for production printing is configured to determine that the transition to production printing is possible when a plurality of consecutive pass judgments by the pass/fail judgment means are determined as a condition. The density value measuring means measures the density value of each of a plurality of solid patches printed in a range corresponding to each ink fountain key of the test printed material. a density-related index deriving means for deriving the number of solid patches included in the value as a density-related index;
The pass/fail determining means determines that the test printed material is acceptable when the density-related index derived by the density-related index deriving means is equal to or greater than the number of targets, which are target indices, and the density-related index deriving means 2. The printing press according to claim 1, wherein means for judging that the test printed material is rejected when the density-related index derived in the above is less than the target number. The density value measuring means measures the density value of each of a plurality of solid patches printed in a range corresponding to each ink fountain key of the test print,
a density-related index deriving means for deriving an average density value obtained by dividing a total density value obtained by summing the measured density values of the plurality of solid patches by the number of the solid patches, as a density-related index;
The pass/fail determination means determines that the test print is acceptable when the difference between the average density value derived by the density-related index deriving means and the target density value, which is the target index, is within a set range. and means for judging that the test printed matter is rejected when the difference between the average density value derived by the density-related index deriving means and the target density value is outside the set range. A printing machine according to claim 1.