JPH01218835A - Apparatus for automatically adjusting density of in-line printed matter - Google Patents

Abstract

PURPOSE:To stably obtain printed matter having uniform and proper density without requiring density adjusting work by an expert, by presetting the density standard of in-line printed matter and operationally comparing the same with measured data and feeding back the comparing result to control the amount of ink. CONSTITUTION:The density data IF1 by color of in-line printed matter 1 is calculated to be stored in a correction circuit 42. The printing density data at every color sent out from a sensor 13 is applied to an averaging part 51 to calculate the average density by each region of (m) printed matters and density data IF2 by color is sent to a correction circuit 52 to perform the correction corresponding to a printing speed V to calculate density data IF3 by color. The inputted density data IF1 by color from a standard setting part 40 is compared with the density data IF3 by color from a measuring part 50 by color at every region of printed matter by a comparing part 61. The comparing result is sent out to a feedback part 62. A control signal 53 is formed at every ink pot and successively sent out to an ink pot automatic adjusting part 63 to control density within a real time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic inline print density adjustment device that automatically adjusts the density of inline prints.

[Prior Art] Conventionally, there has been no device that automatically adjusts the density of printed matter during in-line printing. Therefore, density adjustment of conventional inline printed matter has relied exclusively on artificial means. In other words, in general, proof printing was performed, and based on the color quality, the operator in charge made judgments at first glance, and manually adjusted the printing press's ``ink scale''.

[Problems to be Solved by the Invention] As described above, in the past, the amount of ink was adjusted by visual inspection by the operator, and only a skilled operator could make the adjustment, leading to problems such as manpower shortages, etc. A problem had arisen. Even a highly skilled operator cannot avoid the intervention of human variation.

For this reason, it has been difficult to obtain printed matter that is uniform and has an appropriate density.

Therefore, the present invention makes it possible to stably obtain printed matter with a uniform and appropriate density without requiring a skilled operator to adjust the density, thereby improving quality, reducing paper waste, and reducing costs. The L1 objective is to provide an in-line print density automatic adjustment device that can be used.

[Means for Solving the Problems] In order to solve the above problems and achieve the objects, the present invention has adopted the following means. That is, in order to preset the standard for the density of inline printed matter, the density information of the reference printed matter is input, and this input information is separated into color-specific density information for each of the four colors, predetermined corrections are made for each color, and this information is is stored in memory as tour information. On the other hand, the density of the inline printed matter being printed is detected as color-specific density information for each of the four colors, the detected information is subjected to a predetermined correction, and this is stored in the memory as measurement information. And the reference information and a
llll constant information is compared with the constant information by a comparing means, and the result of the comparison calculation is fed back to adjust the amount of ink used for printing.

[Function] By taking such measures, the following effects are achieved. In other words, the density of the inline printed matter being printed is automatically adjusted, eliminating the need for manual density adjustment by skilled operators as in the past.Furthermore, constant feedback control is used to adjust the density, ensuring uniform density. It is possible to stably obtain appropriate printed matter.

[Example] FIG. 1 is a schematic diagram of a detection unit for detecting density information for each color of an inline printed matter. Reference numeral 1 indicates an inline printed material, which is conveyed via rollers 2 and 3 as shown by the arrow. Note that the rollers 2 and 3 are each provided with a rotary encoder 4.5 for position detection. In order to detect the density of the printed matter 1 running on the outer peripheral surfaces of the rollers 2 and 3,
First and second detectors 10 and 20 are installed, respectively. The first detector 10 is configured such that a light beam from a light source 11 is irradiated onto, for example, the back surface of the printed matter 1, and the reflected light is received by a sensor 13 through a rotary color filter 12. The rotary color filter 12 has filter elements for extracting each color light mounted on a rotary plate, and these filter elements are intermittently inserted into the optical axis by the rotating operation of the rotary plate, thereby extracting only the required color light. 11 is designed to lead to a sensor 13. The second detector 2o is also configured similarly to the first detector 10 described above.

21 is a light source, 22 is a rotary color filter, and 23 is a sensor. In this way, each sensor 13 and 23 can extract density information for each color.

FIG. 2 is a diagram showing the field of view and detection area for density information detection of the inline printed matter 1 by the sensors 13 and 2B. The printed matter 1 that is conveyed from left to right in the figure has l on both the front and back sides.
Each page is printed as shown by a, lb, and lc. In the figure, rectangular frames indicate the field of view of the sensors 13 and 23.

For example, regarding the sensor 13, B1 indicates the field of view during the detection of the density of the printing section 1a of the first page 11 from the encoder 4 at timing t1, and B3 receives a signal indicating the start of the printing section 1a of the first page. shows the field of view when the sensor 13 starts operating,
B2 shows the field of view during density detection of the printed section 1a of the first page, and B3 shows the field of view when density detection of the printed section 1a of the first page is finished and density detection of the printed section 1b of the second page is started. It shows the field of view. Note that the printing portion of each page is divided into n areas AI, A2 . ...Printed separately into An. Each of the above areas AI, A2. ...An corresponds to the number of ink fountains of the target printing machine, and the number can be variably set.

FIGS. 3 and 4 are a top view and a perspective view of the reference input unit 30 for inputting reference information for adjusting the print density for each area and color of the inline printed matter 1. FIG. As shown in the figure, the proof plate mounting table 31 is yellow, black, cyan, and magenta (hereinafter abbreviated as Y, C, and M).
A proof print 32 is set as a reference printed matter given reference information for four colors, and the RAD 33 moves back and forth as indicated by the arrows to input information on this proof print 32 to scan it. There is.

The information input head 33 uses a halogen lamp, an incandescent lamp, or the like to illuminate the surface of the proof sheet with light l! A36 and a line sensor 37 consisting of a CCD or the like that receives reflected light from the surface of the proof sheet are attached, and the "density information for each color" of the proof sheet 32 can be inputted by the scanning. There is.

FIG. 5 is a block diagram showing the configuration of a signal processing system in the automatic print density adjustment device. Note that this block diagram shows a case where signal processing is performed based on detection information from the first detector 10. 40 is an I, I, semi-setting section, which includes the reference input 30 mentioned above, an averaging section 41, and a correction circuit 42.
It consists of

As already explained, the base manual section 30 is for inputting density information for each color of the proof sheet 32.

The averaging unit 41 is a circuit that calculates density information IF for each color for each region of the proof print 32 based on the input information.

The correction circuit 42 corrects the difference in sensitivity characteristics of each color of the sensor 37 based on the color density information Fo obtained by the averaging section 41, captures each type of light source 36; and performs correction for each type of proof sheet 32. Correction of midtones, highlights, and shadows.

This circuit performs various corrections such as the above, sets color density information IF, and stores both color density information IFo for each area before correction and color density information IF after correction processing. .

Reference numeral 50 denotes a measuring section for measuring the printing density of each color of inline printed matter, and is composed of the sensor 13 and the position detection encoder 4 in the above-mentioned detecting section, and other circuits. The averaging unit 51 is a circuit that calculates color-specific density information F2 for each region of the printed matter 1 based on the color-specific printing density signal S2 sent from the sensor 13. Speed detection section 5
3 is a circuit for detecting the conveyance speed of the printed material 1; The correction circuit 52 uses the speed V of the printed material 1 obtained by the speed detection section 53.
Color density information IF2 obtained by the averaging unit 51 based on
61 is a comparison unit that compares the color density information IF with the color density information IF3, and 62 is a circuit that calculates the color density information IF3 by correcting the color density information IF3. This is a feedback unit for generating a feedback signal S3 that controls the ink fountain automatic adjustment unit 63 based on the ink fountain automatic adjustment unit 63.

Note that timing signals S1 and S4 are output from the encoder 4 for position detection;
1 is a sensor 13. Averaging section 51° comparison section 61. The timing signal S4 is applied to the feedback unit 62, and the timing signal S4 is applied to the sensor 13 and the speed detection unit 53.

The operation of this embodiment will be described below with reference to the control timing chart shown in FIG. 6 and the timing chart of the speed detection section 53 shown in FIG. 7.

In the reference input section 30, color-specific reference information for automatically adjusting the density of the printed matter 1 is measured. That is, the information input head 33 once scans the proof sheet 32 set on the proof stand 31 from the left end to the right end in FIG. 3 and FIG. 41.

Then, in the averaging section 41, the information human power head 33
Color-specific density information IFo of the proof print for each color of Y, C, and M is calculated for n areas that are divided in advance in a direction perpendicular to the scanning direction of . The correction circuit 42 performs corrections based on the sensitivity characteristics of each color of the sensor 37, corrections based on the type of light source (halogen, incandescent light), etc., corrections for intermediate gradations, highlight areas, and shadow areas based on the type of proof sheet 32,
If the methods for measuring the print densities of the inline printed matter 1 and the proof sheet 32 are different, corrections are made for each color, density information IF for each color is calculated, and density information for each color IFo and density information IF for each color are calculated. are both stored in the correction circuit 42.

On the other hand, the sensor 13 determines the printing density M1 of the inline printed matter 1 in real time. In this case, the sensor 13 receives a timing signal S from the position detection encoder 4.
1, the printed matter is measured from the start point tl to the end point t3 of the page to be measured. m for one color in advance
If it is decided that the printing density of each sheet is constant at 1-1, then the number of sheets is 1 (shown as m-3 in Figure 6).
, the signal S1 received from the position detection encoder 4 is counted, and the relayer 12 sequentially counts the signal S1 received from the position detection encoder 4 (Y → -
C-M-Y...). sensor 1
The printing density information for each color sent from the printer 3 is sent to an averaging unit 51 to calculate the average density for each area for m sheets, and the calculated density information IF2 for each color is sent to the correction circuit 52.

As shown in FIG. 7, the speed detection unit 53 uses a clock signal S5 having a frequency sufficiently higher than the timing signal S4 given from the position detection encoder 4, and counts the number of clock signals S5 during the pulse period of the signal S4. The count number V obtained by doing this is sent to the supplementary iE circuit 52 as speed information of the printed matter 1.

In the hlil rotation 52, the received color density information IF2 differs due to the difference in the printing speed V of the printed matter 1, so
This color-specific density information IF2 is corrected according to the printing speed V, and color-specific density information 1F3 is calculated. This calculated density information IF for each color is sent to the comparison section 61.

The comparison section 61 compares the inputted color density information IF from the reference setting section 40 and the color density information IF3 from the measurement section 50 for each color and each area of the printed matter. The result is sent to the feedback section 62. Feedback section 62
Then, feedback signals are generated for each area (A1°A2, -An) and for each color (Y, C, M). That is, for each region, that is, for each ink fountain, an adjustment signal S3 is generated to reduce the amount of ink when the ink concentration is high and to increase the amount of ink when the ink concentration is low.
This is sequentially sent to the ink fountain automatic adjustment section 63. The ink fountain automatic adjustment section 63 sequentially performs the above adjustment in the order of the received adjustment signals S3. Therefore, as shown in Figure 6,
For example, after the measurement unit 50 detects Y with respect to the human input signal S2, during the period when K is detected, the ink fountain automatic detection unit 63 detects the Y color measured at the previous timing based on the feedback adjustment signal S3. The concentration is being adjusted. In this way, real-time concentration 5 can be achieved.

The above explanation is about a case where the first detector 10 is used to detect the density of one side of the printed matter 1, this is compared with reference information, and the print density of the above-mentioned side is automatically adjusted based on the result. However, the second detection ″r
Of course, the density can be detected on other sides of the printed matter 1 using A20, and the density can be automatically adjusted in the same manner as described above. In this way, the density of the front and back sides of the inline printed matter 1 can be automatically adjusted.

Note that the present invention is not limited to the embodiments described above. For example, although the proof print 32 is shown as the reference print, it may be a print other than the proof, or it may be a photograph, a picture, or the like. As a result of the comparison by the comparison unit 61 in FIG.
As shown by the broken line X in the figure, the correction circuit 5 in the measuring section 50
2, that is, the color density information IF3, is used as the reference setting unit 40.
It is also possible to add a means to replace the output of the correction circuit 42, that is, the reference information IF, and thereafter perform density adjustment based on this reference information IF1. It goes without saying that various other modifications can be made without departing from the gist of the present invention.

[Effects of the Invention] According to the present invention, the density of inline printed matter is automatically adjusted, so there is no need for a skilled operator to adjust the density.Furthermore, since the adjustment is constantly performed through feedback control, uniform and appropriate density can be achieved. It is possible to provide an in-line print density automatic adjustment device that can stably obtain printed matter, thereby improving quality, reducing paper waste, and reducing costs.

[Brief explanation of the drawing]

Figures 1 to 7 are diagrams showing one embodiment of the present invention, in which Figure 1 is a schematic diagram of a detection unit that detects density information for each color of inline printed matter, and Figure 2 is a schematic diagram of a detection unit that detects density information of inline printed matter by a sensor. 3 and 4 are plan views and perspective views showing the configuration of the reference input section; and Section 5 is a block diagram showing the configuration of the signal processing system in the automatic print density adjustment device. , FIG. 6 is a control timing diagram for controlling printing density, and FIG. 7 is a timing diagram for speed detection. 1... Inline printed matter, 2.3... Roller, 4°5... Rotary encoder, 10.20... Detector, 11.21.36... Light source, 12.22... Rotation Formula color filter, 13. 23... Sensor, 30... Reference input section, 31... Proof print installation stand, 32... Proof print, 33... Information manual head, 34... Guide roller , 35... U-shaped frame, 37... Line sensor, 40... Standard setting section, 41.51... Averaging section, 42° 52... Correction circuit, 50... Measuring section ,
53... Speed detection section, 61... Comparison section, 62...
Fitoback section, 63... Ink point automatic adjustment section. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 4 53 M'/
CM Figure 6 Figure 7

Claims (1)

[Claims] An input means for inputting the density information of the reference printed matter in order to preset the density standard of the inline printed matter, and the density information inputted by this input means is separated into color-specific density information for each of four colors, and correction is performed for each color. means for storing color-specific density information corrected by the means as reference information; means for detecting the density of the inline print being printed as color-specific density information for each of four colors; and detecting by the detecting means. means for correcting density information for each color, means for storing the corrected density information for each color as measurement information, means for comparing and calculating the reference information and measurement information, and a means for performing a comparison calculation by the means. 1. An in-line print density automatic adjustment device comprising means for receiving the result as a feedback signal and adjusting the amount of printing ink.