JPH04118236A - Density measurement device for printed matter - Google Patents

Abstract

PURPOSE:To make it possible to measure instantaneously density information on measurement points in a single sheet of printed matter by arranging density measurement sensors freely at positions corresponding to density control charts and providing a lift device which allows the density measurement sensors to come in contact with the surface of printed matter. CONSTITUTION:Printed matter is sucked by a suction orifice 27 of an adsorption device 26 from below measurement spots. Then any number of density setting sensors 23 are allowed to descend simultaneously using a lifting device until their sensor heads come in contact with the surface of printed matter so that an outer light does not enter the sensors. Light is emitted to the printing surface shielded from alight source in the sensor 23. A reflective light is condensed to a one spot using an optical fiber and then is converted to a voltage by a photo-electric sensor after passing through various color filters. The voltage thus converted is converted to a density value by a specified circuit which is a circuit for analyzing density information. Any number of density values thus converted is graphed to provide an operator with current print information.

Description

Detailed Description of the Invention "Object of the Invention" (Industrial Application Field) The present invention is directed to the production of printed matter on a flatbed printing machine or the like equipped with an inking device, which is an ink supply device that performs normal printing including proof printing. The present invention relates to a line type density measuring device which is useful for density measurement and can instantaneously obtain density information for each divided range from a print management control string in a printed matter.

(Prior art) In plate making printing work, before the actual printing called actual printing, proof printing is performed to inspect the printing plate obtained by plate making and to obtain a standard printed matter for actual printing. is commonly done.

Since this proof is an inspection of the actual printing, it is desirable that it be printed under conditions close to the actual printing. In other words, it is better to use the production printing press for proof printing, but the production printing press is not designed to be convenient for printing small quantities like proof printing, and the efficiency of the printing press is For operational reasons, proof printing is performed by a proof printing machine, which is a proof printing machine, that is, a flatbed printing machine.

Furthermore, even if it is not a proof print but a final print, a small number of copies,
For example, even when printing about 500 copies or less, it is not economical to operate a printing press for final printing, and printing is performed using a flatbed printing press such as a proofing machine.

A flatbed printing machine such as a proofing machine performs printing by running a frame including an ink roller and a blanket cylinder on a main body frame having an inking device at at least one end.

The thickness of the result of this proof print (one factor that affects the thickness of the proof is how to manage the amount of ink applied to the ink roller. Conventionally, the work of applying the required amount of ink to the ink roller was done by an operator. By measuring the solid area of the print management control strip printed on the printed matter with a densitometer at several locations, and comparing and examining the measured value with the standard density value obtained from experience from color balance etc.
Based on experience, ink was applied to an ink roller using a spatula.

That is, apply ink to the ink roller with a spatula, and
~4 sheets of printing material were printed, and the solid areas of the control strip for print management on the printed matter were measured using a densitometer at arbitrary locations to determine whether the amount of ink was excessive or insufficient in general or locally.

For proof printing, only about 12 to 20 sheets are usually printed, so it is necessary to achieve the specified density with a small number of prints and print stably, so the density must be measured as many times as possible and at as many locations as possible. It's more interesting!
The amount of B increases, and operators experience fewer printing errors.

However, in the current calibration field, the number of density measurements and locations are reduced as much as possible in order to shorten printing time. The number of measurement points on one printed sheet is about 2 to 3.

(Problem B to be solved by the invention) However, with the conventional method of manually controlling the amount of ink applied to the ink roller based on the operator's experience, it requires great skill to do it properly.
Furthermore, it is difficult to always accurately control the amount of ink, and as a result, this is the biggest cause of variations in the quality of proof printed matter.

For proof printing work, the number of copies printed is 10 to 20.
Since the number of sheets is small, it is about 2 times from the start of printing.
It is necessary to adjust so that the target print density is reached after ~5 sheets. In addition, in proof printing, the printing plate is replaced at tM2, and other changes in conditions that affect the density of printed matter, such as changes in the condition of dampening water and variations in the time interval between each printing, occur in proof printing. Since the amount of ink consumed and the amount of ink supplied are severe, the management method used in actual printing, which balances the amount of ink consumed and the amount of ink supplied, cannot be applied to proof printing.

As a result of investigation, the present inventors found that seismic intensity measurements occur frequently when the number of printed sheets is small (occurs in proof printing where printing plates are frequently replaced and printing conditions vary greatly),
The present invention has been achieved, and the present invention improves the various drawbacks of the conventional methods described above, and provides a line-type density measuring device that can instantaneously measure density information at a large number of measurement points in one printed sheet. It provides:

"Structure of the Invention" (Means for Solving the Problems) The present invention arranges an arbitrary number of density measurement sensors at positions corresponding to a plurality of density management charts printed in the margins of a pattern on printing paper. This density measuring device is equipped with a lifting device that brings the density measuring sensor into contact with the surface of the printed matter, and further includes a scraping device that moves the density measuring sensor in the direction of the management chart as needed, and a device that positions the printing paper during measurement. Regarding.

The device of the present invention is normally installed in a color booth or the like.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a side view showing an outline of a flatbed printing press.

A dampening device 2 is installed at both ends of the main body frame 1.
An inking device 3 is installed, and a frame 7 including a blanket 4, a water roller 5, and an ink roller 6 runs on the main body frame 1.

A plate plate 8 and a paper plate 9 are provided within the main body frame 1. Furthermore, a loading table for printing materials and a paper feeding device 10 are provided in the main body frame 1, and a printing material loading table and a paper ejecting device 11 are provided in the pedestal 7. Plate plate 8
The printing plate to be printed is loaded onto the paper surface plate 9, and the material to be printed is loaded onto the paper platen 9 from the paper feeder from the loading table.The mount 7 is moved back and forth on the main body frame 1, and dampening water and ink are applied to the printing plate. granted,
The ink on the printing plate is transferred to the printing material via the blanket 4, printing is performed, and the paper is ejected from the paper platen 9 to the stacking table by the paper ejecting device 11.

Note that the embodiment shown in FIG. 1 shows a flatbed printing machine that uses a dampening device and is printed using a normal PS plate as a printing plate, but the embodiment shown in FIG. Of course, the present invention can also be applied to cases where resin letterpress printing is used without the need for printing, or cases where one type of dryography is used. Furthermore, when performing multicolor printing, the printing plate is usually replaced for each color. It should be noted that the present invention is of course applicable not only to flatbed printing presses but also to other printing presses.

FIG. 2 shows a perspective view showing an outline of the color booth. 1
Reference numeral 6 indicates a lighting device, 17 a thermohygrometer, 18 a touch sensor type input device, 19 a switch, 20 a control device, 21 an output device, and 22 a concentration measuring device.

A normal color stand is used to evaluate the stamp surface of printed matter, but the one of the present invention has a suitability management mechanism during printing (moisture content, printing pressure of plate and paper surface plate, image area control, number of printed sheets, etc.), It is also equipped with a printing press operation management mechanism (timer and counter settings, jamming, etc.), a registration control device, and a line-type density measurement device, and has added central printing control.

A line-type density measuring device 22 that simultaneously measures measurement points equal to or less than an arbitrary number of ink fountain divisions, a control device 20 that controls the devices attached to each of the color booths described above, and an output device 21 that writes measured values, management item data, etc. , C
This is a color booth equipped with a touch sensor type input device 18 etc. that can be given instructions on the RT.

3 and 4 are a front view and a plan view for explaining the line type concentration measuring device 22 according to the present invention. In FIGS. 3 and 4, since the number of concentration sensors is arbitrary, some of them are shown using dotted lines. In other words, the number of concentration measurement sensors is not only the same number as the number of ink fountain divisions, but also one sensor for every 2, 3, or 5 ink fountain divisions.
It may be one piece.

Concentration measurement sensors typically include a light source, a filter, a photoelectric sensor and a circuit to control the output voltage.

23 is a concentration measurement sensor, 24 is a column with lifting means, 25
26 is a suction device, 27 is a suction port, 28 is a lifting device, 29 is a substrate for controlling the sensor, 30 is a sensor head, 31 is a density management chart, 32 is a printed matter, 33 is a firmness, 34 is a The paper calibration sensors are shown respectively.

A measurement method in a line type concentration measuring device that simultaneously measures a large number of measurement points according to the present invention will be explained.

The printed material is taken out from the paper discharging device 11, placed on a color table, and the printed color is selected. When the printed color is set, the tension 33 moves. After the movement is completed, the print is physically collided with the ate and the tension to complete the cent. When the setting is completed, the printed matter is suctioned from below the plurality of measurement points through the suction port 27 of the suction device 26, thereby minimizing measurement errors due to wrinkles, etc. After the suction is performed, an arbitrary number of concentration measuring sensors 23 are simultaneously lowered by the lifting device 28 under timer control until the sensor heads come into contact with the print surface to prevent outside light from entering the sensors. An arbitrary number of density measurement sensors descend to the print surface, and after contact is completed, the density measurement sensor 23
Light from an internal light source hits the printed surface inside the sensor, which is shielded from light, and the reflected light is focused into a single point by an optical fiber, passes through filters of each color, and is converted into voltage by a photoelectric sensor. The converted voltage is converted into a concentration value by a predetermined circuit that analyzes concentration information. The arbitrary number of converted density values is graphed as shown in FIG. 5 to provide the operator 4° with information on the current printing status. The graph shown in FIG. 5 provides density information for each measurement location with respect to the standard density of 1.60 for cyan.

After the measurement and graph display are completed, the concentration measuring section is raised by the lifting device 28 to the position before the measurement.

After the sensor rises, the printed matter is transferred to the paper ejection device 11,
Continue printing, and after 3 to 4 sheets have passed, repeat the above operation and take measurements. Perform the same measurement when changing the color when printing.

"Effects of the Invention" The line-type density measuring device of the present invention can measure many measurement points simultaneously, so it minimizes machine stoppage time during printing, greatly improves printing speed, and improves stability. This enabled printing in the same state.

[Brief explanation of the drawing]

FIG. 1 is a side view of a flatbed printing press, FIG. 2 is a perspective view of a color booth which is the density measuring device of the present invention, and FIGS. 3 and 4 are front views of the line type density measuring device of the present invention. FIG. 5 shows a diagram and a plan view, and FIG. 5 shows a concentration measurement result graph. The main symbols in the figure are 1-main frame, 3-inking device, 7-mount, 8-plate surface plate, 9-paper surface plate, 10-1 paper feed bag, 11-paper discharge device, 22- Line type concentration measuring device, 23-concentration measurement sensor, 26-adsorption device, 28-
A line type concentration sensor lifting device, 31-chard for concentration management, and 33-hari are shown, respectively.

Claims (1)

[Claims] 1. An arbitrary number of density measurement sensors are arranged at positions corresponding to a plurality of density management charts printed in the margins of the picture on the printing paper, and the density measurement sensors are brought into contact with the surface of the printed matter. A density measuring device for printed matter, characterized in that it is equipped with an elevating device for vertically moving the printed matter. 2. A density measuring device for printed matter, further comprising a conveying device for moving the printing paper in the direction of the management chart and a device for positioning the printing paper during measurement.