JPH062406B2 - Flatbed proof press - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a flat stand of a type in which printing paper is placed on a surface plate, and a pedestal to which a blanket roll is attached moves on the surface plate to perform printing on the printing paper. The present invention relates to a proof printing machine, and in particular, it is a flatbed proof printing machine in which the printing state of a proof printing can be easily grasped by measuring the printed print management scale with a detection means and obtaining print management data. It is about.

Conventionally, it is customary to print a pattern portion and various management scales on a printed matter by a proof press. In addition, the management method often depends on a method in which a proof printing machine operator looks at a pattern portion, or a method in which a proof printing machine operator measures the density of a print management scale.

However, the former depends on the proficiency level of the proof printing press operator who determines the density of the printed matter, and also the visual proficiency level of the proof printing press operator, the situation at the time of visual check, and the illusion of the design content. , A valid evaluation cannot be made. Further, in the subsequent steps, particularly in the printing steps of the second, third and fourth colors, it is possible to perform printing while keeping the color balance with the first color as a reference, but the first color does not have the reference color printing, so visual judgment is extremely difficult. Further, even if the color balance is visually maintained, the density may fluctuate depending on the proof printing lot. In the printing process of this machine, proof prints are printed on a printing plate having various layouts. At this time, it is difficult to make the density balances of the proof prints inconsistent and to keep the density balances constant.

The latter case is a method of measuring the density of the scale. This method is usually performed by the proof press operator appropriately, and the interval of the density measurement depends on the individual difference of the proof press operator,
Alternatively, it is indefinite depending on the frequency of inking.

FIG. 1 is an explanatory diagram of an operation for measuring the density of a print management scale. The printing paper (3) and printing plate (4) are placed on the surface plate (2) of the flatbed proof press (1).
(5) and an ink kneading roll (6) are attached, and a mount (7) is equipped with a dampening swimwear roll, an ink coating roll, and a blanket roll, and the mount (7) is a surface plate (2). By moving on, dampening swimwear roll, inking roll,
The blanket roll also moves with it. As a result, the fountain solution and ink adhere to the printing plate (4), the ink is further transferred to the blanket roll, and then transferred from the blanket roll to the printing paper (3) for printing. In the case of multicolor printing, the printing plate and ink are replaced, or a plurality of similar proof presses are used to perform overprinting on the same printing paper.

In performing printing in this manner, the print management scale is printed for each color in the margin of the printing paper. To obtain print management data such as density from this print management scale, remove the printing paper from the proof printing machine every time you print, carry it to the pedestal (8) where the densitometer is installed, and manually The densitometer (9) is operated to measure the concentration. For this reason, obtaining print management data is a very laborious task.

Furthermore, since the number of densitometers is generally much smaller than the number of proof presses, there is often a large distance between proof presses and densitometers. In this case, the work of obtaining print management data becomes even more troublesome. If a long time is spent for measuring the density of printed matter without continuous operation in proof printing, the dampening water on the plate surface of the printing plate (4) on the proof press (1) evaporates, The proof printing operator manually supplies the dampening water with a sponge or the like, and the printing conditions cannot be made constant due to the difference in the dampening water condition. Further, it is not preferable to spend unnecessary time between printing due to changes in the ink state of the blanket roll ink kneading roll. Therefore,
It is unavoidable to reduce the frequency of operations for obtaining print management data using the densitometer or the like as described above.

As described above, ink viscosity adjustment, which is an appropriate means for stabilizing the quality of printed matter in the calibration plate, is achieved by only using visual inspection of the design and density measurement of the management scale that takes a long time and is infrequent. In this state, it is impossible to effectively adjust the amount of ink to the left and right of the ink roller and the amount of dampening water.

On the other hand, several types of automatic concentration measuring devices are on the market. Inside the device, the printed matter is placed at a fixed position so that the densitometer self-runs to measure the density of the control scale, or the part of the printed matter to be measured is stored in the vertical and horizontal coordinates, and automatically. There is a device to measure the part you want to measure, but in comparison with when using a manual densitometer, it takes a certain time to carry the printed matter from the proof printing machine to a separate stand, and to measure it. It can be said that there is almost no effect such as increasing the measurement frequency.

Generally, the variation in the density of the printed matter by the proof printing machine appears even in the direction perpendicular to the printing direction, the edge of the printed matter, the tail of the printed matter, and the same position of the continuous printed matter. In particular, due to the scale of the inking, the variation is the largest in the direction perpendicular to the printing direction. In addition, since it is difficult to measure the density of the density variation of the printed matter as described above, most of them are currently performed by the operator's intuition.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional drawbacks and to provide a flatbed proof printing machine having a detecting means with high measurement accuracy, which performs calibration with a standard plate for each measurement.

Next, the present invention will be described in more detail with reference to the drawings.

FIG. 2 is an explanatory view of a part of the gantry of the flatbed proof printing machine of the present invention. The printing paper (3) placed on the surface plate (2) is installed on the gantry (7). The ink is transferred by the blanket roll that receives the ink from the printing plate (4)
Printing is performed. In this case, printing is performed from left to right in the figure.

In this case, on the printing paper (3), in addition to the picture portion (10), the print management scale (11) is printed at two places in the margin.

An example of the print management scale (11) used in the present invention is shown in FIG.

This print management scale is printed with patterns of three types of halftone dots, and in this embodiment, patterns of halftone dots 30% (7
1), halftone dot 70% pattern (72) and halftone dot 100% (solid) pattern (73) are printed. Incidentally, (75) is a timing mark provided so that the data of each halftone dot pattern (71), (72), (73) can be detected by the data detecting means moving in the direction of the arrow (74) described later. .

As the timing mark, as shown in FIG. 7, a solid patch is printed in parallel with the print management scale and used as a timing mark (90), and a dedicated timing sensor provided separately is provided for the timing mark (90). Arrow up
Timing can also be set by passing in the (91) direction. The print management scale is not limited to that shown in FIG. 6, and the number of halftone dots may be three or more.

Reference numeral (85) shown in FIG. 2 is a calibration standard plate, which is provided for the following reason. That is, the detection means described later includes a light source, a light receiving element, an amplifier, etc., but these show characteristic deterioration over time, deterioration of the light amount in the light source due to temperature drift, etc., and characteristic changes in the light receiving element, amplifier. The output is not always constant even if the same object is measured.

In the heel state, it is of course impossible to accurately detect the data. Therefore, it is necessary to electrically correct the data taken in by the detecting means. The standard plate for calibration (85) is necessary to obtain the data.

The calibration standard plate (85) consists of the data detection means (1
It must be installed directly below the path through which 3) passes and at the same height as the printing paper. The installation location may be immediately before the dampening water roller, on a printing platen other than the printing plate, on a printing platen other than the printing paper, but preferably the printing plate platen (2) as shown in FIG. The space between ′ and the printing platen (2) is good. As the calibration standard plate, only white, only white / black, and those having three or more types of reflection density differences can be used. In this embodiment, white / black ones are installed. Materials are color tape, exposed photographic paper, printed matter,
You can use things that have been wetted with paint, but for durability and stability, it is better to use white paint on the blackboard and the blackboard. It is also important that the material can be washed if it becomes dirty.

Further, in order to set the measurement timing of the standard plate, it is desirable to provide timing marks as in the case of the print management scale.

On the other hand, a bar (12) is attached to the end of the gantry (7) parallel to the axis of the blanket roll, and a data detection means (13) is attached to the bar (12). In the example shown in FIG. 2, the print management scale (11) and the print management data detection means (13) are present at two places respectively and have a corresponding positional relationship.

The data detection means (13) has an adjustable mounting position along the bar (12) so that it can be fixed at a position where it passes over the printed control scale (11). is there.

FIG. 3 shows an embodiment of the data detecting means (13).

The light receiving element (14) is for photoelectrically converting by receiving reflected light of the light irradiated on the printed print management scale (11), a photoelectric tube utilizing the photoelectron emission effect, a photomultiplier tube,
Various elements such as a photoconductive cell utilizing the photoconductive effect and a photodiode utilizing the photovoltaic effect can be used, and the shape thereof may be a single body or an array. Further, for example, when the output current or voltage is weak like a photodiode, the amplifier (15) is used to increase the width.

The amplifier (15) needs to be close to the light receiving element (14). Distance (d) between data detection means (13) and printing paper (3)
When is large, external light may enter the light receiving element (14), which may be a cause of affecting the measurement accuracy. Therefore, keep the distance (d) as small as possible, and if there is a risk that the outside light will enter the light receiving element (14) as a light amount that cannot be ignored in terms of measurement accuracy compared to the light amount by the light source (16), block the light. The plate (24) is extended as much as possible, and the shading plate (24) and the data detection means (1
It is preferable that the outside of the bottom portion (25) of 3) is provided with a light absorbing layer such as black paint so that the influence of outside light can be suppressed. By doing so, the external light reaching the light receiving element (14) becomes extremely weak and hardly affects the measurement accuracy. However, due to the structure of the proof press, the distance
When (d) cannot be reduced or when the light-shielding plate (24) cannot be extended, external light may enter more than the case where the above-mentioned measures are taken on the light-receiving element (14). If is constant, a calibration curve or the like may be created in advance, this data may be stored in a storage device, and a calibration curve may be appropriately called to correct the measured value.

The light source (16) may be various kinds such as a halogen lamp, a tungsten lamp, a high frequency lighting fluorescent lamp, etc., but the halogen lamp is preferable from the viewpoint of light quantity and stability. The normal angle of the chief ray from the print control scale (11) and the light source (16) is 30
The angle is preferably from 60 to 60, but is preferably 45. It may be necessary to keep the light receiving element (14) as far as possible in order to reduce the influence of the heat generated by the light source (16) on the light receiving element (14). It may be necessary to cover the light receiving element sufficiently. Light from a light source sufficiently distant from the light receiving element is transmitted by an optical fiber to irradiate the print management scale (11). Alternatively, it is possible to receive the light reflected by the print management scale (11) with an optical fiber and transmit it to a light receiving element that is sufficiently distant from the light source, downsizing the print management data detection means, and receiving light by heat from the light source. In some cases, it is effective in reducing the fluctuation of the element.

A light reflector (18) may be attached to the light source (16) to increase the amount of light. The light source (16) or the light passing through the optical fiber from the light source illuminates the print management scale (11) through the small hole (19). The small hole (19) is for preventing reflected light from other than the print management scale (11) from entering the light receiving element (14). The light reflected from the print management scale (11) is a cylinder
It enters the light receiving element (14) through (20). The cylinder (20) is for preventing the light from the light source (16) from directly entering the light receiving element (14). In front of the light receiving element (14), use the spectral filter (2
1) Install. The spectral filter (21) may be either a seratin filter or an interference filter. G. B or amber filter can be converted. Also the light source
The lens (2) between the print control scale (11) and the spectral filter (21) between the print control scale (11) and the print control scale (11).
2) and (23) can be placed to collect light and improve efficiency.
Also, by mounting the lenses (22) and (23), the light source (16)
It is also possible to prevent stray light from the light receiving element (14) from entering.

Next, processing of measured data will be described based on the block diagram of the data processing circuit shown in FIG.

The pedestal (7) moves over the surface plate for printing on the printing paper (3).
In the figure, it moves from left to right, and in the process, the data detection means (13) first obtains an electric signal according to the amount of reflected light from the calibration standard plate (85). This electric signal is inverted by the inversion amplification circuit (31), logarithmically taken by the log circuit (32) and converted into density data, and this is converted into digital data by the analog-digital conversion circuit (33).

The switching circuit (34) switches the signal flow because the processing circuit after that is different between when measuring the calibration standard plate (85) and when measuring the scale (11) of the printing paper (3). This switching circuit (34) should, for example, detect the end of measurement of the calibration standard plate at the passage position of the gantry and automatically switch to the data processing side of the print management scale based on that signal. You can Standard plate (85) white,
Each density data of black is stored in the standard plate reflection density memory circuit (35), and the standard plate reference density memory circuit (37) is provided separately.
The standard black and white density data of the standard plate stored in the above is compared and calculated by the correction coefficient calculation circuit (36), and the coefficient for correction of the print management data is determined by this, and the correction coefficient storage circuit It is stored in (38).

Next, the gantry (7) moves further while printing the pattern (10) on the printing paper (3), and subsequently the print management scale (11) is printed, and the print management scale (11) is printed. It is measured by the detection means (13). The detection timing is based on the timing mark as described above. In this embodiment, halftone dot 3
0% pattern (71), halftone dot 70% pattern (72), halftone dot 10
Measured in the order of 0% pattern (73), and the inversion amplification circuit
(31), log circuit (32), A / D conversion circuit (33), and switching circuit (34) are sent to the correction circuit (39). The correction circuit (39) multiplies the print management density data by the correction coefficient of the correction coefficient storage circuit (38) to perform the above-described calibration for the purpose. The calibrated print management density data is stored in the reference print density data storage device in the comparison calculation circuit (40) with a pattern of 30% halftone dots, a pattern of 70% halftone dots, and a 100% halftone dot. By comparing with the standard density data of the pattern, the difference in the density value of each halftone dot or the state of the dot gain is obtained.

The result of this calculation is output to an output device such as a CRT display or printer, and the operator of the proof printing machine can take appropriate action such as adjusting the ink amount and adjusting the ink viscosity by looking at the output result. It becomes possible to take

The above processing circuit, CRT display, printer, etc. may be set on a table placed near the printing machine.

FIG. 5 is an explanatory diagram showing an example of the output result to the CRT display (61) as the output means.

The display (61) of FIG. 5 shows the density (62) and dot gain (64) of the print management scale, the reproduction curve (63) based on the reference print density data, and the reproduction curve obtained from the measurement result. (64) and appropriate treatment method (65) as necessary (ink viscosity adjustment, horizontal balance, dampening water, etc.) can be indicated. In this example, density information from several sheets before is also shown.

Further, in the case of a one-color flatbed proof press, four flatbed proof presses are centrally controlled, or data stored in the print management data storage means (30) is stored on a magnetic tape,
By using a magnetic card, floppy disk, etc., the data can be transferred to the flatbed proof printing machine in the next step, and the second and third colors
The flatbed proof printing machine for the fourth and fourth colors can also output the density data for print management in the previous step.

There are various print management scales, which are often printed at a plurality of places. In such a case, by attaching a plurality of data detecting means, the density data for print management at these plurality of places can be obtained. Can be obtained.

Further, the data detecting means can be adapted to various printed matters by adjusting the attachment position of the scale for print management along the bar (12) in parallel with the axis of the blanket roll.

As described above, according to the flatbed proof press of the present invention, it is possible to obtain the print management density data of the print management scale immediately after printing.

Therefore, appropriate processing for the next printing can be swiftly performed, and by transmitting the density data for print management to the operator of the proof printing machine of the next color, the previous color and the operator of the proof printing machine are in charge. It becomes possible to work in consideration of the balance with the colors to be used. Further, the output data can be used as a reference material for a proof printed matter as a printing sample of this machine when managing the later printed matter or creating a printing plate for this machine.

Since the number of proof prints is at most 20 or less, it is possible to obtain print management data for individual proof prints and use the data, which facilitates quality control.

Moreover, since the print management data is calibrated, accurate data measurement and management data output are always possible.

[Brief description of drawings]

FIG. 1 is an explanatory view of how to obtain print management data using a conventional flatbed proof press, FIG. 2 is a partial explanatory view of the flatbed proof press of the present invention, and FIG. 3 is an explanation of print management data detecting means. FIG. 4 is a block diagram of a print management data processing circuit in the flatbed proof press of the present invention, FIG. 5 is an explanatory diagram of an output example by a CRT display, and FIGS. 6 and 7 are print management scales. The respective explanatory views are shown. (1)… Flatbed proof press (2)… Surface plate (3)… Printing paper (4)… Printing plate (5)… Damping water roll (6)… Ink mixing roll (7)… Stand (8)… Table (9) ... Densitometer (10) ... Picture part (11) ... Print management scale (12) ... Bar (13) ... Print management data detection means (14) ... Light receiving element (15) ... Amplifier (16) … Light source (18)… Reflector (19)… Small hole (17), (20)… Tube (21)… Spectral filter (22), (23)… Lens (39)… Correction circuit (40)… Comparison operation Circuit (50) ... Computing means (60) ... Output means (61) ... Display (62) ... Density (63), (64) ... Reproduction curves (71), (72), (73) ... Halftone dot pattern (74) )… Arrows (75), (90)… Timing marks (85)… Standard plate

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Claims (1)

[Claims] 1. A printing plate and printing paper are placed on a surface plate,
In a flatbed proof printing machine that prints a picture and a print management scale on the printing paper by moving a stand to which a blanket roll is attached on the surface plate, the stand is installed on the stand and receives a light source and its reflected light. Data detecting means including a light receiving element for converting into an electric signal, a calibration standard plate installed at a place other than the place where the printing plate and the printing paper are placed, and the calibration standard plate is measured by the data detecting means. A circuit for converting the amount of reflected light thus obtained into a density data, and a correction coefficient calculation circuit for calculating a correction coefficient by comparing the density data of the standard plate with the reference density data of the standard plate stored in advance, A correction method for correcting the print management density data from the print management scale on the printing paper obtained by the data detection means using the correction coefficient. And a calculation means for comparing the corrected print management density data with the separately input reference print density data to obtain data indicating a printing state, and an output means for outputting the calculation result. A characteristic flatbed proof press.