JP4279164B2 - Method and apparatus for preventing stains on printed matter - Google Patents

Description

  The present invention relates to a printed matter stain prevention method and apparatus suitable for preventing stains on a printed matter caused by a dampening water adjustment failure of a printing press.

  Generally, in a printing press such as a newspaper web offset press, a printing plate on which an image line portion to which ink adheres and a non-image line portion to which dampening water adheres is mounted on the plate cylinder surface, and then the plate cylinder is mounted. Ink and dampening water are supplied to the plate, and printing is performed by transferring the ink on the surface of the plate cylinder onto the printing sheet through a blanket cylinder having a rubber blanket mounted on the surface. Since a gap for mounting the blanket is formed in the axial direction on the surface of the blanket cylinder in such a printing press, no ink adheres to the portion corresponding to the gap portion of the blanket cylinder of the printing sheet. (Hereafter, this part is called a blank page part).

  Normally, clean printing can be performed if the supply amount of ink and fountain solution is appropriate. Ink adheres to the image area, and the ink adhering to the non-image area is transferred to the original non-image area on the printing sheet via the blanket cylinder, and ink stains (hereinafter simply referred to as “stain”). ) Will occur.

  Stain on the printed sheet is likely to occur if the ink supply amount is higher than the appropriate value or the dampening water supply amount is lower than the appropriate value. It depends. For this reason, the operator visually checks whether or not the print sheet is stained, and if the print sheet is stained, the amount of dampening water supplied is increased to suppress the occurrence of the stain. I am doing so.

Patent Document 1 discloses a technique for automatically detecting whether or not dirt is generated on a printed print sheet and inspecting the quality of the printed matter. As shown in FIG. 9, in the printing machine according to Patent Document 1, the printing pattern of the printing sheet 50 is optically coupled onto the light receiving element by each printing device 51a, 51b, 51c, 51d, and is incident on each light receiving element. A line camera 52 is provided for detecting the density of the print sheet 50 by taking out the intensity of light as an electric quantity. A detection signal of the print sheet 50 detected by the line camera 52 is input to the processing circuit 53. . Further, here, as shown in FIG. 10, the printing sheet 50 has two rows in the flow direction of the printing sheet 50 for one rotation of the plate cylinder 54 and the blanket cylinder 55 (an area indicated by reference numeral 62 in FIG. 10). A total of four patterns in two rows are printed in the paper width direction. Then, the processing circuit 53 extracts the detection signal of the blank paper portion 60 from the detection signal obtained by the line camera 52 based on the rotation cycle information of the blanket cylinder 55 and uses it as a reference signal. The detection signal of the non-image portion 61 of the print sheet 50 is extracted from the detected signal to obtain a difference from the reference signal. If this difference exceeds an allowable value, it is determined that the print sheet 50 is contaminated. To do.
Japanese Patent No. 2566292

  However, with the technique disclosed in Patent Document 1, it is possible to detect that the print sheet 50 is contaminated, but the operator must manually adjust the dampening water supply amount thereafter. For this reason, the adjustment work may take time due to a difference in the skill level with respect to the adjustment operation of the operator, and the print sheet 50 that has flowed during this time is wasted, resulting in a large amount of waste paper.

  The present invention was devised in view of such problems, and provides a method and apparatus for preventing smudges on printed matter that can reliably prevent stains occurring on the printed matter without depending on the skill level of the operator. With the goal.

For this reason, according to the first aspect of the present invention, there is provided a method for preventing smudges of a printed matter, using an IRGB densitometer, a mixed color density in a non-printing region corresponding to a gap portion of a blanket cylinder in a printed matter, and a printing region in the printed matter. a step of obtaining a mixed color density of non-image area, said non-printing area color mixture density and the non-image region with respect to the non-printing area by color conversion and color mixing concentration of the non-image area A step of obtaining a stain density, a step of obtaining a dampening water increase amount of each ink color corresponding to the stain concentration based on a correspondence relationship between a preset stain concentration and a dampening water increase amount, and a current dampening water A step of obtaining a target dampening water supply amount obtained by adding the dampening water increase amount to a supply amount and a step of adjusting the dampening water supply amount so as to be the target dampening water supply amount are performed. Toi .
According to a second aspect of the present invention, there is provided an anti-smudge method for printed matter of the present invention, using an IRGB densitometer, a mixed color density of a non-printing region corresponding to a gap portion of a blanket cylinder in the printed matter, and a non-image line in the printed region of the printed matter. Determining the mixed color density of the non-printing area, the mixed color density of the non-printing area and the mixed color density of the non-image area corresponding to the halftone dot area ratio of each ink color, A step of obtaining a stain density of the image area, and a step of obtaining a dampening water increase amount of each ink color corresponding to the stain density based on a correspondence relationship between a preset stain concentration and a dampening water increase amount; Obtaining a target dampening water supply amount obtained by adding the dampening water increase amount to the current dampening water supply amount; and adjusting the dampening water supply amount so as to be the target dampening water supply amount. Characterized by performing To have.
According to a third aspect of the present invention, there is provided an anti-smudge method for printed matter according to a third aspect of the present invention. Determining the color mixture density of the non-printing area, and the color mixture density of the non-printing area and the color mixing density of the non-printing area corresponding to the density of each ink color, A step of obtaining a stain density of the region, a step of obtaining a dampening water increase amount of each ink color corresponding to the stain density based on a correspondence relationship between a preset stain density and a dampening water increase amount, Performing a step of obtaining a target dampening water supply amount obtained by adding the dampening water increase amount to a dampening water supply amount and a step of adjusting the dampening water supply amount so as to be the target dampening water supply amount Features .

According to a fourth aspect of the present invention, in the method for preventing smudges of printed matter of the present invention, in the method according to any one of the first to third aspects, the step of obtaining the smear density includes a predetermined halftone dot area ratio, color mixture density, and Based on the correspondence relationship, the step of obtaining the dot area ratio of each ink color corresponding to the mixed color density of the non-printing area, and the non-printing area based on the correspondence relation between the halftone dot area ratio and the monochrome density set in advance Based on the step of obtaining the monochrome density corresponding to the halftone dot area ratio and the correspondence relationship between the previously set halftone dot area ratio and the mixed color density , each ink color corresponding to the mixed color density of the non-image area is determined. Obtaining a halftone dot area ratio, obtaining a monochrome density corresponding to the halftone dot area ratio of the non-image area based on the correspondence between the preset halftone area ratio and the monochrome density , setting the halftone dot area ratios and monochromatic dark Solid density deviation and based on a corresponding relationship between the solid density, corresponds to the deviation between the monochrome density and monochrome density of the non-image area of the non-printing area of the original halftone dot area ratio of the non-printing area And a step of setting the solid density deviation as the dirt density.

According to a fifth aspect of the present invention, there is provided a printed matter stain prevention method according to any one of the first to fourth aspects, wherein when the target dampening water supply amount exceeds a preset upper limit value, the wetness is reduced. It is characterized in that the amount of salt water supplied is set to the above upper limit value.
According to a sixth aspect of the present invention, there is provided a method for preventing smearing of printed matter according to any one of the first to fourth aspects, wherein the dampening water supply amount exceeds a preset upper limit value when the target dampening water supply amount exceeds a preset upper limit value. And setting the water supply amount to the above upper limit, and determining the ink reduction amount of each ink color corresponding to the stain density based on the correspondence relationship between the preset stain density and the ink reduction amount, and the current ink The step of obtaining the target ink supply amount by subtracting the ink reduction amount from the supply amount and the step of adjusting the ink supply amount so as to be the target ink supply amount are performed.

Fouling prevention apparatus of a printed material of the present invention according to claim 7, the IRGB densitometer disposed on a traveling line of the printed materials, the gap portion of the blanket cylinder in the printed material from the measurement information obtained by the IRGB densitometer mixture of color mixture density and the color mixture density arithmetic means for obtaining a mixed color density of non-image area of the printing area in the printed material, color mixing concentration and the non-image area of the non-printing areas of the non-printing area corresponding to Based on the correspondence between the stain density calculating means for obtaining the stain density of the non-image area with respect to the non-printing area from the density , and the correspondence between the preset stain density and the dampening water increase amount, A dampening water increase amount calculating means for obtaining the ink color dampening water increase amount, and a target dampening water supply amount for obtaining the target dampening water supply amount by adding the dampening water increase amount to the current dampening water supply amount. Computing means and above It is characterized in that a Shimegishime and means for adjusting the dampening water supply from the dampening water supply device so that the water supply quantity.
The printed matter anti-smudge device of the present invention according to claim 8 corresponds to the gap portion of the blanket cylinder in the printed matter from the IRGB densitometer arranged on the printed line and the measurement information obtained by the IRGB densitometer. A mixed color density calculating means for obtaining a mixed color density of the non-printing area and a mixed color density of the non-image area in the printed area of the printed matter, and a mixed color density of the non-print area and a mixed color density of the non-image area. Corresponding to the halftone dot area ratio of each ink color, and a stain density calculating means for obtaining the stain density of the non-image area with respect to the non-print area, and correspondence between the preset stain density and the dampening water increase amount Based on the relationship, the dampening water increase amount calculating means for obtaining the dampening water increase amount of each ink color corresponding to the stain density, and the target dampening by adding the dampening water increase amount to the current dampening water supply amount. Seeking water supply A target dampening water supply amount calculation means, is characterized in that it includes a means for adjusting the dampening water supply from the dampening water supply device so that the target dampening water supply.
According to a ninth aspect of the present invention, there is provided an anti-smudge device for printed matter according to the present invention, which corresponds to a gap portion of a blanket cylinder in the printed matter from an IRGB densitometer arranged on a running line of the printed matter and measurement information obtained by the IRGB densitometer. A mixed color density calculating means for obtaining a mixed color density of the non-printing area and a mixed color density of the non-image area in the printed area of the printed matter; and a mixed color density of the non-print area and a mixed density of the non-image area. Corresponding to the density of each ink color, and a stain density calculating means for obtaining the stain density of the non-image area with respect to the non-print area, and a correspondence relationship between a preset stain density and a dampening water increase amount A dampening water increase amount calculating means for obtaining a dampening water increase amount for each ink color corresponding to the stain density, and a target dampening water supply amount by adding the dampening water increase amount to the current dampening water supply amount Goals for seeking A water supply amount calculation means, and is characterized in that it includes a means for adjusting the dampening water supply from the dampening water supply device so that the dampening the target water supply amount.

A smudge prevention device for printed matter according to a tenth aspect of the present invention is the device according to any one of the seventh to ninth aspects, wherein the smear density calculating means calculates a dot area ratio and a color mixture density set in advance. Based on the correspondence, the halftone dot area ratio of each ink color corresponding to the mixed color density of the non-printing area and the halftone dot area ratio of each ink color corresponding to the mixed color density of the non-image area Based on the correspondence relationship between the area ratio calculation means and the preset dot area ratio and monochrome density , the monochrome density corresponding to the dot area ratio of the non-printing area and the dot area ratio of the non-image area and monochrome density calculating means for obtaining a monochromatic density corresponding to, based on a corresponding relationship between the preset dot percent monochrome density and solid density, the non under dot percent of the non-printing area corresponding to deviation between the monochrome density and monochrome density of the non-image area of the printing area A solid density deviation calculation means for calculating a solid density difference that is the solid density deviation is characterized in that it includes a dirt density setting means for setting as the dirt concentration.

The device for preventing smudges of printed matter of the present invention according to claim 11 is the device according to any one of claims 7 to 10, wherein the target dampening water supply amount exceeds a preset upper limit value. And determining means for determining, and when the determining means determines that the target dampening water supply amount exceeds the upper limit value, the control means sets the dampening water supply amount to the upper limit value. It is characterized by.
12. Symbol mounting fouling prevention device of printed material of the present invention is the apparatus according to any one of claims 7 to 10, whether or not exceeded the upper limit of water supply amount dampening the target previously set determining means for determining, based on a corresponding relationship between stain concentration and the ink reduction amount set pre Me, an ink reduction amount calculating means for calculating an ink reduction amount of each ink color corresponding to the dirt concentration, the current ink supply And a target ink supply amount calculating means for subtracting the ink reduction amount from the amount to obtain a target ink supply amount, wherein the control means determines that the target dampening water supply amount has exceeded the upper limit value by the determining means. If it is determined, the water supply amount dampening above in conjunction with setting the upper limit value described above, is characterized by adjusting the ink supply amount from Lee Nki feeder so that the target ink supplying amount.

According to a thirteenth aspect of the present invention, in the apparatus according to the twelfth aspect , the determination means determines whether or not the target ink supply amount exceeds a preset lower limit value. It is characterized by comprising warning means for issuing a warning when the determination means determines that the target ink supply amount exceeds the lower limit value.

According to the smear prevention method for printed matter of the present invention as set forth in claims 1 to 3 , after obtaining the stain density of the non-image area from the mixed color density of the non-print area and the non-image area measured by the IRGB densitometer. The target dampening water supply is obtained by adding the dampening water increase amount to the current dampening water supply amount by obtaining the dampening water increase amount based on the correspondence relationship between the preset dirt concentration and the dampening water increase amount. Since the amount of dampening water supplied is adjusted so that the amount of ink is adjusted, it is possible to reliably prevent stains generated on the printed matter without depending on the skill level of the operator.

According to the stain prevention method for printed matter of the present invention as set forth in claim 4 , each ink color of the non-image area is obtained by color-converting the mixed color density of the non-print area and the non-image area measured by the IRGB densitometer. The soil concentration can be determined.
According to fouling prevention method of the printed material of the present invention according to claim 5, since the target dampening water supply amount is set dampening water supply amount When exceeding the upper limit value preset to the upper limit value, the dampening water An excessive supply can be prevented.

According to the method for preventing smearing of printed matter of the present invention described in claim 6, since the dampening water supply amount is set to this upper limit value when the target dampening water supply amount exceeds the preset upper limit value, An excessive supply can be prevented. Also, the ink reduction amount of each ink color corresponding to the stain density is obtained based on the correspondence relationship between the preset stain density and the ink reduction amount, and the target ink supply amount obtained by subtracting the ink reduction amount from the current ink supply amount Therefore, even if it is difficult to eliminate stains on the printed matter only by adjusting the dampening water supply amount, the ink supply amount is adjusted to remove stains generated on the printed matter. It becomes possible to prevent reliably.

According to the smudge prevention device for printed matter of the present invention according to claims 7 to 9 , after obtaining the stain density of the non-image area from the mixed color density of the non-print area and the non-image area measured by the IRGB densitometer. The target dampening water supply is obtained by adding the dampening water increase amount to the current dampening water supply amount by obtaining the dampening water increase amount based on the correspondence relationship between the preset dirt concentration and the dampening water increase amount. Since the amount of dampening water supplied is adjusted so that the amount of ink is adjusted, it is possible to reliably prevent stains generated on the printed matter without depending on the skill level of the operator.

According to the antifouling apparatus of printed matter of the present invention of claim 10 Symbol mounting, the ink in the non-image portion region by the color conversion color mixture density of non-printing area and the non-image area was measured by the IRGB densitometer The stain density of the color can be obtained.
According to the antifouling apparatus of printed matter of the present invention according to claim 11, the target dampening water supply amount is set dampening water supply amount When exceeding the upper limit value preset to the upper limit value, the dampening water An excessive supply can be prevented.

According to the antifouling apparatus of printed matter of the present invention of claim 12 wherein, the target dampening water supply amount is set dampening water supply amount When exceeding the upper limit value preset to the upper limit value, the dampening water An excessive supply can be prevented. Also, the ink reduction amount of each ink color corresponding to the stain density is obtained based on the correspondence relationship between the preset stain density and the ink reduction amount, and the target ink supply amount obtained by subtracting the ink reduction amount from the current ink supply amount Therefore, even if it is difficult to eliminate stains on the printed matter only by adjusting the fountain solution supply amount, the ink supply amount is subsequently adjusted to remove stains generated on the printed matter. This can be surely prevented.

According to the fouling prevention apparatus for printed matter of the thirteenth aspect of the present invention, a warning is issued when the target ink supply amount exceeds the lower limit value, so that the operator can know the abnormality of the printing machine at an early stage.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing a schematic configuration of a newspaper offset rotary press according to an embodiment of the present invention. The newspaper web offset press of this embodiment is a multicolor duplex printing machine, and ink colors [black (k), indigo (c), red (m) along the transport path of the printing sheet (printing paper) 8]. , Yellow (y)] is provided with printing units 2a, 2b, 2c, 2d.

  In the present embodiment, the printing units 2 a, 2 b, 2 c, 2 d include a dampening water supply device 47 </ b> A including a water tank 45, a dampening source roller 46, a metering roller (calling roller) 47, and a dampening roller 48. . The dampening water is stored in the water tank 45, and this dampening water adheres to the dampening original roller 46. Then, the dampening water adhering to the dampening original roller 46 is transferred to the dampening roller 48 by the metering roller 47 and supplied to the plate surface of the plate cylinder 4. In the dampening water supply device 47A of this type, the metering roller 47 reciprocates between the dampening roller 46 and the dampening roller 48, thereby supplying dampening water from the dampening roller 46 to the dampening roller 48. The dampening water supply amount can be adjusted by controlling the reciprocating operation of the metering roller 47.

  The printing units 2 a, 2 b, 2 c, and 2 d include an ink key type ink supply device 7 A that includes an ink key 7 and an ink source roller 6. In this type of ink supply device 7A, the ink supply amount can be adjusted by the gap amount of the ink key 7 with respect to the ink base roller 6 (this gap amount is referred to as the ink key opening). A plurality of ink keys 7 are juxtaposed in the printing width direction, and the ink supply amount can be adjusted in units of the width of the ink key 7 (the ink supply unit width by the ink key 7 is called a key zone). The ink whose supply amount is adjusted by the ink key 7 is appropriately kneaded in the ink roller group 5 and is supplied to the plate surface of the plate cylinder 4 after forming a thin film.

  A gap portion 4a is formed in the plate cylinder 4 in the axial direction, and a printing plate 4b having an image line portion and a non-image line portion is formed on the gap side 4a at the tail end and the tail edge side. The parts are locked and mounted on the surface of the plate cylinder 4. The ink supplied to the plate cylinder 4 preferentially adheres to the image area of the printing plate 4b, while the fountain solution adheres to the non-image area of the printing plate 4b. Similarly to the plate cylinder 4, the blanket cylinder 3 is also formed with a gap portion 3a extending in the axial direction. The rubber blanket 3b engages the cap portion 3a with the tail end and the tail edge side. It is stopped and mounted on the surface of the blanket cylinder 3. As a result, the ink on the plate surface of the plate cylinder 4 is transferred as a pattern to the printing sheet 8 through the blanket cylinder 3, but no ink adheres to the portion of the printing sheet 8 corresponding to the gap portion 3a of the blanket cylinder 3. Therefore, ink stains never occur. Hereinafter, the area where no ink adheres is referred to as a blank area (non-print area), and the area other than the blank area is referred to as a print area (that is, a pattern area including an image line area and a non-image area).

Although not shown in FIG. 1, the newspaper offset rotary press of this embodiment is a double-sided printing, and therefore a pair of printing units 2 a, 2 b, 2 c, and 2 d is provided so as to sandwich the conveyance path of the printing sheet 8. Blanket cylinders 3 and 3 are provided, and for each blanket cylinder 3, a plate cylinder 4, a fountain solution supply device 47A, and an ink supply device 7A are provided.
The newspaper offset rotary press of this embodiment includes a line sensor type IRGB densitometer (IRGB densitometer) 1 further downstream of the most downstream printing unit 2d. The line sensor type IRGB densitometer 1 reflects I (infrared light), R (red), G (green), and B (blue) reflection densities (mixed-color network) in the form of a line in the print width direction of the pattern color on the printing sheet 8. It is possible to measure the reflection density of the entire print sheet 8 or to measure the reflection density at an arbitrary position. Since the newspaper offset rotary press of this embodiment is a double-sided printing, the line sensor type IRGB densitometer 1 is arranged on both the front and back sides so as to sandwich the conveyance path of the printing sheet 8, and the reflection density on both the front and back sides can be measured. .

The reflection density measured by the line sensor type IRGB densitometer 1 is transmitted to the arithmetic unit 10. The arithmetic device 10 is a device that calculates control data for the dampening water supply amount and the ink supply amount, and performs the calculation based on the reflection density measured by the line sensor type IRGB densitometer 1.
Here, FIG. 2 is a diagram showing a schematic configuration of the smudge prevention device for printed matter according to one embodiment of the present invention, and at the same time, a functional block diagram focusing on the smudge prevention control function of the arithmetic device 10.

  The arithmetic unit 10 includes a DSP (digital signal processor, which has a function corresponding to a mixed color network density calculation means) 11 and a PC (personal computer) 12 which are installed apart from the printing press. Conversion unit (having functions corresponding to halftone dot area rate calculation means, monochrome color density calculation means, solid density deviation calculation means, dirt density setting means) 14, dampening water supply amount calculation section (dampening water increase amount calculation means) , Having a function corresponding to the target dampening water supply amount calculation means) 40, a determination unit (determination means) 41, and an ink supply amount calculation part (ink reduction amount calculation means, having a function corresponding to the target ink supply amount calculation means) ) 42, a function as the display control unit 43 is assigned. A line sensor type IRGB densitometer 1 is connected to the input side of the arithmetic device 10, and a control device (control means) 20 built in the printing press is connected to the output side.

  The control device 20 controls the reciprocating operation of the metering roller 47 to adjust the dampening water supply amount and the ink for adjusting the ink supply amount by controlling the opening of the ink key 7. It functions as a supply amount adjusting means. Further, when adjusting the dampening water supply amount, the control device 20 controls a driving device (not shown) that reciprocates the metering roller 47 between the dampening roller 46 and the dampening roller 48. The reciprocating operation can be adjusted independently for each metering roller 47 of the printing units 2a, 2b, 2c, 2d. Further, when adjusting the ink supply amount, an opening / closing device (not shown) for opening and closing the ink key 7 is controlled, and the key opening is adjusted independently for each ink key 7 of each printing unit 2a, 2b, 2c, 2d. be able to. Further, a display device (warning means) 32 is connected to the arithmetic device 10.

FIG. 3 is a diagram showing a processing flow of the antifouling control by the arithmetic unit 10. Hereinafter, the processing content of the antifouling control by the arithmetic unit 10 will be described with reference to FIG.
First, as step S10, the line sensor type IRGB densitometer 1 measures the amount of reflected light i ′, r ′, g ′, b ′ for each pixel on the entire surface of the printing sheet 8. The reflected light amounts i ′, r ′, g ′, b ′ of each pixel measured by the line sensor type IRGB densitometer 1 are input to the DSP 11.

  In step S20, the DSP 11 performs a moving average of the reflected light amounts i ′, r ′, g ′, and b ′ of each pixel in units of a predetermined number of printed sheets, so that the reflected light amount i, r of each pixel from which the noise component has been removed. , G, b are calculated. In step S30, the average mixed color halftone density Io, Ro, Go, Bo of the blank paper portion and the average mixed color halftone density I, R of the non-image portion are selected from the reflected light amounts i, r, g, b on the entire surface of the printing sheet 8. , G, and B are calculated. The positions of the blank paper portion and the non-image portion in the print sheet 8 can be easily grasped by using plate making data acquired from the upstream process. Alternatively, as to the position of the blank paper portion, a rotary encoder may be attached to the blanket cylinder 3 to acquire the rotation period information of the blanket cylinder 3.

  The color conversion unit 14 performs the processes of steps S40, S50, S60, and S70. First, as step S40, the halftone dot area ratios ko, co, mo, yo for each ink color corresponding to the average mixed color halftone density Io, Ro, Go, Bo of the blank page calculated in step S30, and the non-image portion Are calculated as the halftone dot area ratios k, c, m, and y of the respective ink colors corresponding to the average mixed color halftone densities I, R, G, and B. The color conversion unit 14 of the PC 12 includes a database 141 that associates the halftone dot area ratio of each ink color with the mixed color halftone density. The database 141 is a print of a newspaper color Japan Color standard printed by the ISO / TC130 National Committee and measured by the line sensor type IRGB densitometer 1 [standard color halftone dot area ratio (k, c, m, y), a color conversion halftone density (I, R, G, B), and a conversion table that defines the correspondence between color coordinate values (L, a, b)]. For this calculation, the database 141 is used, and based on the correspondence stored in the database 141, the halftone dot area ratio of each ink color corresponding to the average mixed color halftone density Io, Ro, Go, Bo of the blank paper portion is calculated. The halftone dot area ratio of each ink color corresponding to the average mixed color halftone density I, R, G, B of the non-image area is calculated as the halftone dot area ratio k, c, m, y. Calculate as

  Next, in step S50, the color conversion unit 14 performs the single color halftone densities Dako, Dako, Damo, Dayo of each ink color corresponding to the halftone dot area ratios ko, co, mo, yo calculated in step S40. And the monochrome halftone densities Dak, Dac, Dam, and Day for each ink color corresponding to the halftone dot area ratios k, c, m, and y of the non-image area. For this calculation, a map as shown in FIG. 4 is used. FIG. 4 is an example of a map in which the monochromatic halftone density measured when the halftone dot area ratio is changed is plotted as a characteristic curve, and is created from data measured in advance. Here, a map is used in which the increase rate of the monochrome halftone density gradually increases as the halftone dot area ratio increases. In the example shown in FIG. 4, the black halftone dot area ratio ko of the blank paper portion and the black halftone dot area ratio k of the non-image portion are compared with the map, so that a single color halftone halftone screen is obtained from the characteristic curve in the map. The density Dako and the monochrome halftone density Dak of the non-image area are required. In this manner, the color conversion unit 14 determines the single color halftone densities Dako, Dako, Damo, Dayo and the single color halftone densities Dak, Dac, Dam, Day for each ink color.

  Next, in step S60, the color conversion unit 14 sets each ink corresponding to the deviation between the monochrome halftone density Dako, Dako, Damo, Dayo of the blank paper portion and the monochrome halftone density Dak, Dac, Dam, Day of the non-image portion. Color solid density deviations ΔDsk, ΔDsc, ΔDsm, ΔDsy are calculated. The solid density also depends on the halftone dot area ratio. For the same monochrome halftone density, the higher the halftone dot area ratio, the lower the solid density. Therefore, the color conversion unit 14 performs calculations using a map as shown in FIG. FIG. 5 is an example of a map in which the monochromatic halftone density actually measured when the monochromatic solid density is changed is plotted as a characteristic curve for each halftone dot area ratio, and is created from data measured in advance. Here, for each halftone dot area ratio, a map is used in which the monochromatic halftone density increases linearly or substantially linearly as the solid density increases. The color conversion unit 14 selects a characteristic curve corresponding to the halftone dot area ratios ko, co, mo, yo of the blank paper portion for each ink color from the map shown in FIG. 5, and adds the single color halftone density of the blank paper portion to the selected characteristic curve. The solid density deviations ΔDsk, ΔDsc, ΔDsm, and ΔDsy are obtained by associating Dako, Dako, Damo, and Dayo with the monochromatic halftone densities Dak, Dac, Dam, and Day of the non-image area. In the example shown in FIG. 5, when the black halftone dot area ratio ko of the blank paper portion is 75%, the map is obtained by comparing the monochrome halftone density Dako of the blank paper portion and the monochrome halftone density Dak of the non-image portion with the map. The black solid density deviation ΔDsk is obtained from the 75% characteristic curve.

In step S70, the solid density deviations ΔDsk, ΔDsc, ΔDsm, and ΔDsy of each ink color calculated in step S60 are set as the stain densities Dk, Dc, Dm, and Dy of the non-image area with respect to the blank paper portion. The stain density Dk, Dc, Dm, Dy of each ink color calculated by the color conversion unit 14 is input to the dampening water supply amount calculation unit 40.
The dampening water supply amount calculation unit 40 performs the processes of step S80 and step S90. First, as step S80, the fountain solution increase amounts ΔWk, ΔWc, ΔWm, ΔWy corresponding to the stain densities Dk, Dc, Dm, Dy of the ink colors set in step S70 are calculated. For this calculation, a map as shown in FIG. 6 is used. FIG. 6 is an example of a map in which the amount of increase in dampening water, which is considered appropriate when the soil concentration is changed, is plotted as a characteristic curve, and is based on data measured by experiments in advance and data obtained by simulation. Has been created. Here, a map is used in which the increase rate gradually decreases as the dirt density increases. In the example shown in FIG. 6, the dampening water increase amount ΔWk is obtained from the characteristic curve in the map by comparing the black stain density Dk with the map. In this way, the dampening water supply amount calculation unit 40 calculates the dampening water increase amounts ΔWk, ΔWc, ΔWm, ΔWy for each ink color. The dampening water increase amounts ΔWk, ΔWc, ΔWm, ΔWy are increases with respect to the current dampening water supply amount Wko, Wco, Wmo, Wyo.

  In step S90, the dampening water supply amount calculation unit 40 adds the dampening water increase amounts ΔWk, ΔWc, ΔWm, ΔWy calculated in step S80 to the current dampening water supply amounts Wko, Wco, Wmo, Wyo. Thus, the target dampening water supply amounts Wk, Wc, Wm, and Wy are calculated. The dampening water supply amount calculation unit 40 inputs the target dampening water supply amounts Wk, Wc, Wm, and Wy to the determination unit 41.

  In step S100, the determination unit 41 determines whether the target dampening water supply amounts Wk, Wc, Wm, and Wy are within a predetermined range. For this determination, a map as shown in FIG. 7 is used. FIG. 7 is an example of a map in which a target dampening water supply amount that is appropriate for the halftone dot area ratio (image ratio) of each ink color of a pattern is plotted as a characteristic curve. It is created based on data obtained by simulation. Here, a map is used in which the target dampening water supply amount increases linearly or substantially linearly as the dot area ratio increases.

In FIG. 7, a line L ₀ indicates a function of a normal target dampening water supply amount. When normal printing is started, the target dampening water supply corresponding to the dot area ratio of the pattern is referred to with reference to this line L _0. The amount is obtained, and the metering roller 47 is controlled so as to be the target dampening water supply amount. The determination unit 41 sets an upper limit value and a lower limit value (predetermined range) for the target dampening water supply amount in advance as indicated by lines L ₁ and L ₂ in FIG. Here, when the normal target dampening water supply amount indicated by the line L ₀ is N ₀ , the upper limit value indicated by the line L 1 is (N ₀ + N%), and the lower limit value indicated by the line L 2 is (N ₀ −N%). Is set to For example the dot percent of the pattern of black color is a predetermined range if the K ₁₂ is determined by the upper limit value N ₁ and the lower limit value N _2. Then, the determination unit 41 determines whether or not the target dampening water supply amounts Wk, Wc, Wm, and Wy for each ink color are within a predetermined range, and if they are within the predetermined range, the control device 20. Send a signal to In step S110, the control device 20 sets each printing unit 2a, 2b, 2c, 2d so that the amount of dampening water supplied from the dampening water supply device 47A becomes the target dampening water supply amount Wk, Wc, Wm, Wy. The metering roller 47 is adjusted. Since there is a response delay from the start of adjusting the metering roller 47 until the dampening solution adjustment effect reaches the printed matter 8, after a predetermined time has elapsed in step S120 in consideration of the response delay, the process returns to step S10.

  By the way, the occurrence of the stain on the printed material 8 is mainly due to the lack of the dampening water supply amount. Therefore, when the printed material 8 is stained, the dampening water supply amount is increased. Therefore, the case where the target dampening water supply amounts Wk, Wc, Wm, and Wy are not within the predetermined range in step S100 is when the upper limit value is exceeded. Therefore, when the determination unit 41 determines in step S100 that the target dampening water supply amount Wk, Wc, Wm, Wy is larger than the upper limit value, in step S200, the target dampening water supply amount Wk, Wc, Clip (set) Wm and Wy to upper limit values to prevent excessive supply of dampening water. Further, the determination unit 41 transmits a signal to the ink supply amount calculation unit 42 substantially at the same time as the target dampening water supply amounts Wk, Wc, Wm, and Wy are clipped to the upper limit value.

  When the signal is input from the determination unit 41, the ink supply amount calculation unit 42 performs the processes of step S210 and step S220. First, in step S210, ink reduction amounts ΔKk, ΔKc, ΔKm, and ΔKy corresponding to the stain densities Dk, Dc, Dm, and Dy of the ink colors set in step S70 are calculated. For this calculation, a map as shown in FIG. 8 is used. FIG. 8 is an example of a map in which the ink reduction amount that is appropriate when the stain density is changed is plotted as a characteristic curve, and is created based on data measured in advance by experiments or obtained by simulation. ing. Here, a map is used in which the increase rate gradually decreases as the dirt density increases. In the example shown in FIG. 8, the ink decrease amount ΔKk is obtained from the characteristic curve in the map by comparing the black stain density Dk with the map. In this way, the ink supply amount calculation unit 42 obtains the ink reduction amounts ΔKk, ΔKc, ΔKm, ΔKy for each ink color. The ink reduction amounts ΔKk, ΔKc, ΔKm, and ΔKy are reduction amounts with respect to the current ink supply amounts Kko, Kco, Kmo, and Kyo.

  In step S220, the ink supply amount calculation unit 42 subtracts the ink decrease amounts ΔKk, ΔKc, ΔKm, and ΔKy calculated in step S210 from the current ink supply amounts Kko, Kco, Kmo, and Kyo, thereby performing target ink supply. The quantities Kk, Kc, Km, Ky are calculated. The ink supply amount calculation unit 42 inputs the target ink supply amounts Kk, Kc, Km, Ky to the determination unit 41.

  In step S230, the determination unit 41 determines whether or not the target ink supply amounts Kk, Kc, Km, Ky exceed a predetermined range. For this determination, a map is used in which the target ink supply amount, which is appropriate when the halftone dot area ratio (image line ratio) of each ink color of the pattern is changed, is plotted as a characteristic curve. Similar to the map used in the determination of the target dampening water supply amount described above, this map may be created based on data measured by experiments in advance or data obtained by simulation. As for the upper limit value and the lower limit value, appropriate ranges may be set in advance by experiments or the like. Then, the determination unit 41 determines whether or not the target ink supply amounts Kk, Kc, Km, and Ky for each ink color are within a predetermined range, and if they are within the predetermined range, a signal is sent to the control device 20. Send. In step S240, the control device 20 adjusts the ink keys 7 of the printing units 2a, 2b, 2c, and 2d so that the ink amount supplied from the ink supply device 7A becomes the target ink supply amount. Since there is a response delay from the start of adjusting the ink key 7 until the effect of the ink adjustment reaches the printed matter 8, the process returns to step S10 after a predetermined time has elapsed in step S250 considering the response delay.

  By the way, as described above, the occurrence of the stain on the printed material 8 is mainly due to the insufficient supply amount of the dampening water. Therefore, when the printed material 8 is stained, the dampening water is supplied. The amount may be increased, but there may be a case where the dirt does not disappear only by increasing the supply amount of dampening water. Therefore, in the present embodiment, in the above case, control is performed to reduce the ink supply amount while the dampening water is continuously supplied at the upper limit value. However, since the pattern may become thin if the ink supply amount is greatly reduced, a predetermined range is also set for the target ink supply amounts Kk, Kc, Km, and Ky to prevent this. In this way, if the stain does not disappear just by increasing the fountain solution supply amount, the ink supply amount is decreased. Therefore, in step S230, the target ink supply amounts Kk, Kc, Km, Ky are within a predetermined range. The case where it does not fit is when the lower limit value of the predetermined range is exceeded. Therefore, if the determination unit 41 determines in step S230 that the target ink supply amounts Kk, Kc, Km, Ky are smaller than the lower limit values, the target ink supply amounts Kk, Kc, Km, Ky are set to the lower limit values. Clip (set) and prevent ink from drastically decreasing. The determination unit 41 transmits a signal to the display control unit 43 substantially at the same time as the target ink supply amounts Kk, Kc, Km, and Ky are clipped to the lower limit values.

When the signal is input from the determination unit 41, the display control unit 43 causes the display device 32 to display a letter indicating that the stain does not disappear even if the fountain solution supply amount and the ink supply amount are adjusted, thereby indicating an abnormality in the printing press. Alert the operator. As a result, the operator can quickly know that an abnormality has occurred in the printing press. Further, it is preferable to end the dirt prevention control after the warning.
As described above, according to the printed matter stain prevention method and apparatus as one embodiment of the present invention, the target dampening solution supply amount is calculated based on the correspondence between the preset stain concentration and the dampening solution increase amount. In addition, since the dampening water supply device 47A only needs to be controlled so as to achieve the target dampening water supply amount, it is possible to reliably prevent stains generated on the printed matter without depending on the skill level of the operator.

Further, since the control is performed using the IRGB densitometer, the cost of the measuring means can be reduced and the high-speed printing machine such as a newspaper rotary press can be sufficiently handled. The smear density of each ink color in the non-image area can be obtained by color-converting the mixed-color halftone density of the blank area (non-printing area) and non-image area measured by the IRGB densitometer.
Furthermore, since the dampening water supply amount is set to this upper limit value when the target dampening water supply amount exceeds the preset upper limit value, it is possible to prevent excessive supply of dampening water.

Even if it is difficult to eliminate stains on the printed matter only by adjusting the supply amount of the dampening water, the stains generated on the printed matter can be more reliably prevented by adjusting the ink supply amount subsequently.
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, in the present embodiment, in addition to a method including a database 141 that associates the halftone dot area ratio of each ink color with the mixed color halftone density, a known relation that defines the correspondence between the halftone dot area ratio of each ink color and the mixed color halftone density is known. The Neugebauer equation is stored, and the halftone dot area ratio of each ink color is applied to this equation to calculate the mixed color halftone density.

In addition to a method for obtaining a solid density deviation of each ink color corresponding to a deviation between the monochrome halftone density of the blank paper portion and the monochrome halftone density of the non-image portion using a map as shown in FIG. There is also a method in which a well-known Yule-Nielsen equation that defines the correspondence between monochromatic halftone density and solid density is stored, and a solid density deviation is calculated from this equation.
Furthermore, in this embodiment, a line sensor type IRGB densitometer is used, but a spot type IRGB densitometer may be used to scan the print sheet two-dimensionally.

  Further, the method for warning the operator is not limited to the character display by the display device 32. For example, a warning lamp may be turned on or a warning buzzer may be sounded.

1 is a diagram showing a schematic configuration of a newspaper offset rotary press according to an embodiment of the present invention. It is a functional block diagram which paid its attention to the dirt prevention control function of the arithmetic unit of FIG. It is a flowchart which shows the processing flow of the stain | pollution | contamination prevention control by the arithmetic unit of FIG. It is a map which shows the correspondence of a halftone dot area ratio and a monochrome halftone density. 6 is a map showing a correspondence relationship between solid density, halftone dot area ratio, and monochrome halftone density. It is a map which shows the correspondence of dirt density and dampening solution increase. It is a map which shows the correspondence of a halftone dot area rate and target dampening water supply amount. 6 is a map showing a correspondence relationship between a stain density and an ink reduction amount. It is a schematic diagram which shows the conventional quality inspection apparatus of printed matter. It is a top view of printed matter for demonstrating the conventional quality inspection method of printed matter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Line sensor type IRGB densitometer 2a, 2b, 2c, 2d Printing unit 3 Blanket cylinder 3a Gap part 3b Blanket 4 Plate cylinder 4a Gap part 4b Printing plate 5 Ink roller group 6 Ink original roller 7 Ink key 7A Ink supply device 8 Printing sheet (Printing paper)
10 arithmetic unit 11 DSP
12 PC
14 color conversion unit 20 control device built in printing press 32 display device 40 dampening water supply amount calculation unit 41 determination unit (determination means)
42 Ink Supply Amount Calculation Unit 43 Display Control Unit 45 Water Tank 46 Dampening Source Roller 47 Metering Roller 47A Dampening Water Supply Device 48 Dampening Roller 141 Database

Claims (13)

Using IRGB densitometer, a step of obtaining a mixed color density of the non-printing area corresponding to the gap portion of the blanket cylinder, and a color mixture density of non-image area of the printing area in the printed material in printed material,
Determining a contamination concentration of the non-image region with respect to the non-printing area by color conversion and color mixture density of color mixture density and the non-image area of the non-printing area,
Obtaining a dampening water increase amount of each ink color corresponding to the fouling density based on a correspondence relationship between a preset smear density and a dampening water increase amount; and
Obtaining a target dampening water supply amount obtained by adding the dampening water increase amount to the current dampening water supply amount; and
And a step of adjusting the dampening water supply amount so as to be the target dampening water supply amount.   Using an IRGB densitometer to obtain a mixed color density of a non-printing area corresponding to a gap portion of a blanket cylinder in a printed material and a mixed color density of a non-image area in the printed area of the printed material;
  Associating the mixed color density of the non-printing area and the mixed color density of the non-image area with the halftone dot area ratio of each ink color to determine the stain density of the non-image area with respect to the non-print area; and ,
  Obtaining a dampening water increase amount of each ink color corresponding to the fouling density based on a correspondence relationship between a preset smear density and a dampening water increase amount; and
  Obtaining a target dampening water supply amount obtained by adding the dampening water increase amount to the current dampening water supply amount; and
  Adjusting the dampening water supply amount to the target dampening water supply amount.
A method for preventing smearing of printed matter.   Using an IRGB densitometer to obtain a mixed color density of a non-printing area corresponding to a gap portion of a blanket cylinder in a printed material and a mixed color density of a non-image area in the printed area of the printed material;
  Associating the mixed color density of the non-printing area and the mixed color density of the non-image area with the density of each ink color to determine the stain density of the non-image area with respect to the non-print area;
  Obtaining a dampening water increase amount of each ink color corresponding to the fouling density based on a correspondence relationship between a preset smear density and a dampening water increase amount; and
  Obtaining a target dampening water supply amount obtained by adding the dampening water increase amount to the current dampening water supply amount; and
  Adjusting the dampening water supply amount to the target dampening water supply amount.
A method for preventing smearing of printed matter. The step of obtaining the dirt concentration
Obtaining a halftone dot area ratio of each ink color corresponding to the mixed color density of the non-printing area based on a correspondence relationship between a predetermined halftone dot area ratio and the mixed color density ;
Obtaining a monochrome density corresponding to a halftone dot area ratio of the non-printing region based on a correspondence relationship between a halftone dot area ratio and a monochromatic density set in advance;
Obtaining a halftone dot area ratio of each ink color corresponding to the mixed color density of the non-image area based on the correspondence relationship between the preset halftone dot area ratio and the mixed color density ;
Obtaining a monochrome density corresponding to a halftone dot area ratio of the non-image area based on a correspondence relationship between the preset halftone dot area ratio and the monochrome density ;
Based on a corresponding relationship set in advance halftone dot area ratios and monochromatic density and solid density, single-color monochrome density and the non-image area of the non-printing area of the original halftone dot area ratio of the non-printing area determining a solid density deviation corresponding to a deviation between the density,
The solid concentration difference, characterized in that it includes a step of setting as the dirt concentration, contamination prevention method of the printed matter of the mounting serial to any one of claims 1 to 3. The printed matter according to any one of claims 1 to 4, wherein the dampening water supply amount is set to the upper limit value when the target dampening water supply amount exceeds a preset upper limit value. Dirt prevention method. When the target dampening water supply amount exceeds a preset upper limit value, the dampening water supply amount is set to the upper limit value, and
A step of obtaining an ink reduction amount of each ink color corresponding to the stain density based on a correspondence relationship between a predetermined stain density and an ink reduction amount;
Subtracting the ink reduction amount from the current ink supply amount to obtain a target ink supply amount;
The method for preventing smudges of printed matter according to any one of claims 1 to 4 , wherein the step of adjusting the ink supply amount to achieve the target ink supply amount is executed. And IRGB densitometer disposed on a traveling line of the printed materials,
Color mixture density calculation for obtaining the color mixing concentration of non-image region of the print region in the color mixture density and the prints of the non-printing area corresponding to the gap portion of the blanket cylinder in the printed material from the measurement information obtained by the IRGB densitometer Means,
And dirt concentration calculating means for calculating the dirt concentration of the non-image region with respect to the non-printing area by color conversion and color mixture density of color mixture density and the non-image area of the non-printing area,
A dampening water increase amount calculating means for determining a dampening water increase amount of each ink color corresponding to the fouling concentration based on a correspondence relationship between a preset stain density and a dampening water increase amount;
Target dampening water supply amount calculating means for adding the dampening water increase amount to the current dampening water supply amount to obtain the target dampening water supply amount;
An antifouling device for printed matter, comprising: means for adjusting a dampening water supply amount from the dampening water supply device so as to achieve the target dampening water supply amount.   An IRGB densitometer placed on the printed line,
  Color mixing density calculation for obtaining the color mixing density of the non-printing area corresponding to the gap portion of the blanket cylinder in the printed material and the color mixing density of the non-image area in the printing material from the measurement information obtained by the IRGB densitometer. Means,
  The stain density for obtaining the stain density of the non-printing area with respect to the non-printing area by matching the mixed color density of the non-printing area and the mixed color density of the non-printing area with the halftone dot area ratio of each ink color. Computing means;
  A dampening water increase amount calculating means for determining a dampening water increase amount of each ink color corresponding to the fouling concentration based on a correspondence relationship between a preset stain density and a dampening water increase amount;
  Target dampening water supply amount calculating means for adding the dampening water increase amount to the current dampening water supply amount to obtain the target dampening water supply amount;
  Means for adjusting the dampening water supply amount from the dampening water supply device so as to achieve the target dampening water supply amount.
An anti-smudge device for printed matter.   An IRGB densitometer placed on the printed line,
  Color mixing density calculation for obtaining the color mixing density of the non-printing area corresponding to the gap portion of the blanket cylinder in the printed material and the color mixing density of the non-image area in the printing material from the measurement information obtained by the IRGB densitometer. Means,
  A stain density calculation means for determining the stain density of the non-image area with respect to the non-print area by associating the color mixture density of the non-print area and the color mixture density of the non-image area with each ink color density; ,
  A dampening water increase amount calculating means for determining a dampening water increase amount of each ink color corresponding to the fouling concentration based on a correspondence relationship between a preset stain density and a dampening water increase amount;
  Target dampening water supply amount calculating means for adding the dampening water increase amount to the current dampening water supply amount to obtain the target dampening water supply amount;
  Means for adjusting the dampening water supply amount from the dampening water supply device so as to achieve the target dampening water supply amount.
An anti-smudge device for printed matter. The soil concentration calculation means includes:
Based on the preset corresponding relationship between the halftone dot area ratios and color mixture density, and each ink color dot percent of that corresponding to the mixed color density of the non-printing area, corresponding to the color mixture density of the non-image area Halftone dot area ratio calculating means for determining the halftone dot area ratio of each ink color;
Based on a corresponding relationship set in advance halftone dot area ratios and monochromatic density, monochromatic density corresponding to the halftone dot area ratio of the non-printing area, and monochromatic density corresponding to the halftone dot area ratio of the non-image area Monochrome density calculation means for obtaining
Based on a corresponding relationship set in advance halftone dot area ratios and monochromatic density and solid density, single-color monochrome density and the non-image area of the non-printing area of the original halftone dot area ratio of the non-printing area a solid density deviation calculation means for calculating a solid density deviation corresponding to a deviation between the density,
The printed matter stain prevention apparatus according to any one of claims 7 to 9 , further comprising stain density setting means for setting the solid density deviation as the stain density. A determination means for determining whether or not the target dampening water supply amount exceeds a preset upper limit;
The control means sets the dampening water supply amount to the upper limit value when it is determined by the determination means that the target dampening water supply amount exceeds the upper limit value. The smudge prevention device for printed matter according to any one of 7 to 10 . Determination means for determining whether or not the target dampening water supply amount exceeds a preset upper limit ;
Based on a corresponding relationship between stain concentration and the ink reduction amount set Me pre, an ink reduction amount calculating means for calculating an ink reduction amount of each ink color corresponding to the dirt concentration,
A target ink supply amount calculating means for subtracting the ink reduction amount from the current ink supply amount to obtain the target ink supply amount;
When the determination means determines that the target dampening water supply amount has exceeded the upper limit value, the control means sets the dampening water supply amount to the upper limit value and sets the target ink supply amount and so as to Lee and adjusting the ink supply amount from the Nki feeder, printed matter stain prevention apparatus according to any one of claims 7-10. The determination means determines whether the target ink supply amount exceeds a preset lower limit value, and
13. The apparatus for preventing smudges of printed matter according to claim 12 , further comprising warning means for issuing a warning when the determination means determines that the target ink supply amount exceeds the lower limit value.

Images