JP2000103040A - Offset printing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To match the color tone of a printed matter with a small number of test prints by entering a command for stopping an offset printing machine after the end of printing a specified number of sheets to be printed and stopping the printing operation of the offset printing machine after stopping an ink supply to an ink roller group from an ink fountain. SOLUTION: During printing, ink 41 in an ink fountain 40 is transferred to an ink ducting roller 34 by the amount of the ink 41 equivalent to a gap between an ink key 33 and an ink fountain roller 32. Next the ink 41 is applied to a plate cylinder 37 passing through an ink roller group 35 and the like. After that, the ink 41 is transferred to a blanket cylinder 38 and then is transferred to a printing paper 39. In this case, when a command for stopping offset printing is entered by a command input means, a stop command is given to drive means for the ink ducting roller 34 and the ink fountain roller 32, and an ink key opening/closing means to suspend the operation of these means. Further, after the lapse of a specified time, the stop command is given to a drive means for an inking roller 36 and after the lapse of a specified time, the stop command is given to a drive means for the printing machine to suspend the printing operation of the printing machine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an offset printing method for an offset printing press, and more particularly, to an offset printing method capable of reducing the number of test prints.

[0002]

2. Description of the Related Art Conventionally, when printing is performed on a sheet-fed printing press or a rotary printing press, after a printing plate is mounted on a printing unit of each color, ink is supplied in accordance with the pattern area of each printing plate and its distribution. The amount was adjusted and the color tone of the printed matter was adjusted. The color matching was performed by trial printing, but the printed matter during the trial printing naturally has a problem with the color tone and cannot be shipped as a product. Therefore, it is necessary to reduce the number of test prints in order to reduce the cost, and for that purpose, various facilities and methods have been proposed.

[0003] Initially proposed is a mechanical equipment called a picture area ratio meter, which measures the picture area of the printing plate and its distribution,
By calculating the ink key opening, which is a means for adjusting the ink supply amount, and inputting the ink key opening to the printing press, ink is supplied according to the printing plate from the start of printing, and the number of test prints is reduced. Is what you do. Here, the structure of the ink key will be briefly described. The ink key has a structure in which a plurality of blades are arranged along the horizontal axis of the ink source roller, and by changing the distance between the blade and the roller (this is referred to as an opening). The thickness of the ink film on the ink roller is adjusted to control the ink supply amount.

However, it has not been possible to greatly reduce the number of test prints by using the picture area ratio meter alone. That is, when the printing plate (the pattern area and its distribution are different) is replaced, an ink film having a film thickness distribution corresponding to the previous printing plate is formed on the ink roller group. A large number of test prints was required to cope with the film thickness distribution according to the next printing plate. This tendency is remarkable when replacing a printing plate that requires a large amount of ink supply with a printing plate that requires a small amount of ink. In that case, the amount of ink consumed per test print is small. Even if no ink is supplied, a large number of test prints are required until an appropriate film thickness distribution is obtained. In addition, when an appropriate amount of ink is supplied based on the data of the picture area ratio meter, there is a problem that the difference between the consumption amount and the supply amount of the ink is small and the number of test prints is increased.

In order to reduce the number of test prints, there is one disclosed in Japanese Patent Publication No. 4947/94. This means that all the blades of the ink key are uniformly opened before the start of printing, an ink film with a uniform film thickness distribution is formed on the ink roller, and then, based on the data of the pattern area ratio meter, The opening is adjusted.

However, this method can reduce the number of test prints in printing at the initial operation of the printing press, that is, when printing is started rather than when ink is not present on the ink roller group. In the case of replacing and printing, the number of test prints could not be greatly reduced. In other words, when the printing plate is replaced, the ink roller group having the film thickness distribution corresponding to the previous printing plate formed on the ink roller group when the printing plate is replaced is subjected to the ink roller group for a predetermined number of times without supplying and discharging the ink. By rotating, an ink film having a uniform film thickness distribution is formed, and the formed ink film becomes thicker. For this reason, when replacing a printing plate that requires a large amount of ink supply with a printing plate that requires a small amount of ink, the amount of ink consumed per test print is small. Therefore, there is a problem that a proper number of test prints is required until an ink film having an appropriate film thickness distribution is obtained. Of course, in that case, the thick ink film becomes a uniform thickness by being smoothed out, and then is consumed by printing, so that it becomes an appropriate ink film. The amount of ink that must be consumed can be reduced in comparison, but as long as no ink is carried out, the total amount of ink on the ink roller group does not decrease, until the ink film with an appropriate film thickness distribution However, the problem that the number of test prints corresponding to the above is necessary remains unsolved.

In order to reduce the total amount of ink on the ink roller group that needs to be consumed, Japanese Patent Application Laid-Open No.
There is one disclosed in Japanese Patent No. 73248. This is because when replacing the printing plate, the ink rollers are rotated at the maximum speed and the ink is collected in the ink fountain, thereby minimizing the ink film on the ink rollers and setting it to the initial state. The ink is supplied based on the data of the picture area ratio meter to form an ink film having an appropriate film thickness distribution.

However, in this method, since the ink once emulsified is returned to the ink fountain, the performance of the ink is deteriorated, and there is a problem that the working efficiency and print quality are reduced. That is, in offset printing, printing is performed by emulsifying ink and water (referred to as fountain solution) in a balanced manner on a printing plate. As a result, the ink on the printing plate or on the inking roller that supplies ink directly to the printing plate is in an emulsified state, and this emulsified ink is mixed with the raw ink in the ink fountain, and the performance of the ink itself deteriorates Will be done. As a result, defects that occur when the emulsified ink is supplied to the ink roller portion that was originally set for only the raw ink, not the emulsified ink, and excessive emulsification, etc., are likely to occur, and various work defects and printing defects are reduced. Cause For example, as a work defect, there is a defect called roller bald, which is caused by kneading the emulsified ink with the ink roller, water is squeezed out, and the water adheres to the metal roller surface in the ink roller group. This impairs ink transfer and makes printing itself difficult. In addition, for example, poor quality includes a defect called flocculation, in which water is emulsified with the pigment in the ink, not the ink, and the structure of the ink itself is destroyed, resulting in extremely low gloss. This is a defect in which the print quality becomes extremely poor and the print quality is extremely deteriorated. As in these examples, there is a problem that the working efficiency and the print quality are reduced due to the fact that the emulsified ink containing water enters the ink fountain and the ink roller, which are originally assumed to be free of water.

Further, in this method, since the ink is simply collected in the ink fountain, it is impossible to make the film thickness distribution on the ink roller group uniform, and the uneven film thickness distribution is set to the initial state. Then, even if ink is supplied based on the data of the picture area ratio meter, it is difficult to form an ink film having an appropriate film thickness distribution. That is, even if the ink roller group is rotated at the maximum speed and collected in the ink fountain for the ink film having the film thickness distribution corresponding to the pattern of the printing plate, the ink film is fixed at a constant rate (1/2 at a time) regardless of the film thickness distribution (Transfer), the ink is removed, and the film thickness distribution on the ink roller group is not uniform. Of course, to reduce the total amount of ink on the ink roller group, it was possible to relatively reduce the number of prints required for test printing, but test printing suitable for forming an ink film with an appropriate film thickness distribution was possible. The issue of the need for a number remained unsolved.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art, and an object of the present invention is to provide an offset printing method capable of adjusting the color tone of a printed material with a small number of test prints. To provide.

[0011]

Means for Solving the Problems In order to solve the above-mentioned problems, the invention according to claim 1 comprises at least an ink fountain capable of temporarily storing ink, a plate cylinder for printing, and a plate comprising the ink fountain. In an offset printing method for an offset printing press having an ink roller group for supplying ink to a cylinder and an ink key for adjusting a film thickness distribution of an ink film on the ink roller, an instruction for stopping the offset printing machine after printing of a predetermined number of printed materials is completed. And stopping the ink supply from the ink fountain to the ink roller group after inputting the command, and stopping the printing of the offset printing machine after stopping the ink supply to the ink roller group. is there.

That is, according to the first aspect of the present invention,
After the printing of a predetermined number of printed materials is completed, an offset printing press stop command is input, and after the input of the command, the ink supply from the ink fountain to the ink roller group is stopped, and after the ink supply to the ink roller group is stopped, printing of the offset printing press is performed. Therefore, after an operator or the like inputs a stop command to the offset printing press, the supply of ink to the ink roller group is stopped first, and then the printing by the offset printing press is stopped. As a result, after the ink supply is stopped, printing with only the ink on the ink roller consumes the ink on the ink roller and the ink on the printing plate. The total amount of the ink film is minimized.
Therefore, an ink film having a film thickness distribution corresponding to the printing plate after replacement can be quickly formed, and the number of test prints can be reduced to a minimum. For example, from a printing plate requiring a large amount of ink supply, Even when the printing plate is replaced with a small printing plate, the color tone of the printed matter can be adjusted with a small number of test prints. Further, since the total amount of ink on the ink roller group is reduced without collecting the ink in the ink fountain, various defects due to the emulsified ink do not occur.

Here, an important difference in the technical concept from the prior art will be described. In the prior art, the first printing is completed as usual, and the ink is printed at the start of the next printing after switching the printing plate. While the ink on the roller group is smoothed or the ink is collected, the present invention is different in that the ink is consumed at the end of printing. A major feature here is that at the end of printing, a printing plate corresponding to the thickness distribution of the ink film on the ink roller group is mounted on the plate cylinder, and if this printing plate is used, ink can be reduced very efficiently. On the point. In other words, the portion of the ink film on the ink roller group where the thickness of the ink film is large has a large pattern area on the printing plate, so a large amount of ink can be reduced by printing one sheet, and the ink can be uniformly collected by closing the ink key. It is possible to consume ink more efficiently than in the prior art. In addition, when the printing press is stopped, the number of rotations is gradually reduced, and all the printed matter during that time becomes waste paper (defective printing). It consumes no extra paper and is extremely efficient. Furthermore, when using a printing plate corresponding to the film thickness distribution of the ink film on the ink roller group to reduce the amount of ink, there is a point in time when the minimum amount of ink becomes the film thickness distribution of the smooth ink film. Therefore, if the printing is stopped at this point, the state can be maintained, and the ink film having the film thickness distribution corresponding to the printing plate after the replacement is more quickly placed on this minimum and smooth ink film thickness distribution. It can be formed.

[0014] Here, the stop of printing will be described. There are a plurality of methods for stopping printing of the offset printing press. In the present invention, printing may be stopped by any method. For example, the printing may be stopped by stopping the paper supply, or the cylinder may be removed (the printing may be stopped by moving the blanket cylinder).
In some machines, the plate cylinder moves at the same time. ), The printing may be stopped, the driving of the printing press may be stopped, and these selections or combinations may be appropriately adopted. However, the present invention is not limited to this, and even printing may be performed. If stopped, another method may be adopted.

According to a second aspect of the present invention, there is provided an ink fountain capable of temporarily storing ink, a plate cylinder for printing, an ink roller group for supplying ink from the ink fountain to the plate cylinder, In an offset printing method for an offset printing press having an ink key for adjusting a film thickness distribution of an ink film on a roller, an offset printing press stop command is input after printing of a predetermined number of printed materials, and after the command input, the ink fountain is removed. Stopping the ink supply to the ink roller group, stopping the ink supply to the plate cylinder after stopping the ink supply to the ink roller group, and stopping the printing of the offset printing machine after stopping the ink supply to the ink roller group. This is an offset printing method characterized by the following.

That is, according to the second aspect of the present invention,
After the printing of a predetermined number of printed materials is completed, an offset printing press stop command is input, and after the input of the command, the ink supply from the ink fountain to the ink roller group is stopped, and the ink supply to the plate cylinder is stopped after the ink supply to the ink roller group is stopped. This is an offset printing method in which the ink supply is stopped and the printing of the offset printing machine is stopped after the ink supply to the ink roller group is stopped. Is stopped, then the ink supply to the plate cylinder is stopped, and then the printing of the offset printing press is stopped. As a result, after the ink supply is stopped, by printing only with the ink on the ink roller, the ink on the ink roller is consumed,
Next, the ink on the printing plate (mounted on the plate cylinder) is consumed, and the total amount of the ink film on the ink rollers when the printing of the offset printing press is stopped is minimized, and the ink on the printing plate is also minimized. Limit.

For this reason, only a minimal amount of ink remains on the printing plate, and it becomes extremely easy to collect the printing plate. In other words, if a large amount of ink remains on the printing plate, the ink will adhere to other parts, which will hinder removal and transport. If the ink on the printing plate is minimal, this effect should be suppressed. Becomes possible. In particular, in recent years, automatic plate exchange devices for printing plates have become widespread, and the removal of used printing plates and the setting of the next printing plate have been automatically performed. As a result, the ink of the used printing plate may adhere to the automatic plate changing device and cause a malfunction, but in this case, since the ink is minimized, the probability of the malfunction is reduced. In addition, it is possible to reduce the trouble of cleaning the ink adhesion. Further, when the ink supply to the plate cylinder is stopped at the time when the film thickness distribution of the ink film on the ink roller becomes smooth, compared with the case where the ink consumption is stopped by stopping the printing as in the first claim. At a more accurate timing, a smooth film thickness distribution is maintained on the ink roller. Therefore, it is possible to more quickly form an ink film having a film thickness distribution corresponding to the printing plate after replacement on the minimum and smooth film thickness distribution of the ink film.

According to a third aspect of the present invention, the timing for stopping the printing or the timing for stopping the ink supply to the plate cylinder is determined by the time when the ink supply to the ink roller group is stopped.
An offset printing method, characterized in that the timing is such that the plate cylinder is rotated a predetermined number of times.

That is, according to the third aspect of the present invention,
By stopping the printing or ink supply to the plate cylinder at the timing when the plate cylinder is rotated a predetermined number of times after the ink supply to the ink roller group is stopped, the film thickness of the ink film on the ink roller group is more precisely uniform. It can be maintained as a proper state. That is, the consumption of the ink on the ink roller group is started from the time when the supply of the ink to the ink roller group is stopped. The amount of consumption is determined by the number of rotations of the plate cylinder (the number of prints). The amount of ink consumed per rotation of the plate cylinder is almost determined by the pattern area of the printing plate and its distribution, and the film thickness distribution of the ink film on the ink roller group is also determined by the pattern area of the printing plate and its distribution. When controlling the ink consumption, it is optimal to control the number of rotations of the printing cylinder (the number of prints).

More specifically, the fact that an ink film having a film thickness distribution corresponding to the printing plate is formed on the ink roller group means that if the ink is consumed using the printing plate, the ink film on the ink roller group will be reduced. There is a timing at which the film thickness distribution of the ink film becomes uniform, which means that it can be controlled by the number of rotations of the plate cylinder. In other words, if ink is consumed using a printing plate, a lot of ink is consumed in one rotation of the plate cylinder in a place where the film thickness distribution is thick, and less ink is consumed in one rotation of the plate cylinder in a place where the film thickness distribution is thin. Therefore, there can be a timing at which the film thickness distribution of the ink film on the ink roller group becomes uniform, and if the consumption of ink is stopped at this timing, a uniform film thickness distribution can be obtained with a minimum amount of ink. Can be formed on the ink roller group, and when printing after replacing the printing plate, an ink with a film thickness distribution corresponding to the printing plate after replacement is placed on this minimum and uniform thickness ink film. A film can be formed quickly and the number of test prints can be reduced to a minimum. Even if a printing plate that requires a large amount of ink supply is replaced with a print plate that requires a small amount of print, a small number of test prints With printed color Together is possible.

Therefore, in the prior art, before the start of printing, all the blades of the ink key are opened uniformly, and an ink film having a uniform film thickness distribution is formed on the ink roller. Compared to the case of adjusting the opening of each blade based on the above, when the ink film is formed with a uniform film thickness distribution with the minimum amount of ink while consuming the ink, and when the printing plate is replaced with a good one with a small amount However, there is no need to increase the density of the printed matter due to an excessive amount of ink, and it is not necessary to perform a large amount of trial printing to reduce the density.

Further, in the prior art, when the printing plate is replaced, the ink roller group is rotated at the maximum speed and the ink is collected in the ink fountain so that the ink film on the ink roller group is minimized. Compared to the case of the initial state, not only the occurrence of defects due to the emulsified ink can be prevented, but also the smooth film thickness distribution can be made the initial state, so that the number of test prints can be further reduced.

Further, when controlling the number of rotations of the plate cylinder, the influence of the rotation speed can be eliminated, and conversely, the ink can be consumed while reducing the rotation speed, and printing can be stopped more efficiently. It is possible to do. 500 to 1000 per minute, especially for web offset presses
In the case of a machine that prints about the same number of sheets, even if printing is stopped, it cannot be done instantaneously.Since printing is stopped while reducing the rotation speed, controlling by rotating the plate cylinder consumes ink. And the cost can be further reduced.

According to a fourth aspect of the present invention, the timing for stopping the printing or the timing for stopping the ink supply to the plate cylinder is determined by the time when the ink supply to the ink roller group is stopped.
This is an offset printing method characterized in that the timing is such that the plate cylinder is rotated for a predetermined time.

That is, according to the fourth aspect of the present invention,
A state in which the film thickness distribution of the ink film on the ink roller group is nearly uniform by stopping the printing or the ink supply to the plate cylinder after the plate cylinder is rotated for a predetermined time after the ink supply to the ink roller group is stopped. It becomes possible. In other words, the consumption of ink on the ink roller group starts when the ink supply to the ink roller group stops,
This consumption is determined by the number of prints. Since the amount of ink consumed for a single print is largely determined by the picture area of the printing plate, it is best to control the number of prints when controlling the amount of ink consumed. It can be controlled by the number of rotations and the rotation time.

In particular, it is difficult to control the number of rotations of the plate cylinder (the number of prints), but if this is controlled by time, it can be easily controlled. In this case, if the number of rotations of the plate cylinder is controlled by the number of rotations of the plate cylinder and the rotation time, it becomes closer to the case where the number of rotations of the plate cylinder is controlled. This is because, in the case of offset printing presses, the printable paper thickness is limited due to the setting of each machine,
Therefore, the rotation speed of the printing press is also constant to some extent. Therefore, even if only the time is controlled, it is possible to obtain a value close to the case where the control is performed by the plate cylinder rotation speed and the rotation time.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram showing the configuration of the present invention. In FIG. 1, 1 is a control means, 2 is a command input means, 3 is a command receiving means, 4 is a roller ink supply stopping means, 5 is an ink feeding roller driving means, 6 is an ink source roller driving means, and 7 is an ink key opening / closing means. , 8 is a plate cylinder ink supply stopping means, 9 is an ink roller driving means, 1
Reference numeral 0 denotes a printing stop unit, 11 denotes a printing press driving unit, 12 denotes a counter, and 13 denotes a rotation speed control unit.

In FIG. 1, the control circuit 1 has at least a command receiving means 3, a roller ink supply stopping means 4, a plate cylinder ink supply stopping means 8, a printing stopping means 10, a counter 12, and a command inputting means 2 The offset printing press stop command input from the control circuit 1
Received at. Next, the roller ink supply stopping means 4 issues a stop command to the ink feeding roller driving means 5, the ink source roller driving means 6, and the ink key opening / closing means 7. As a result, the ink feeding roller stops the swinging motion, the ink source roller stops the rotating motion, and the ink key is closed to stop the ink supply to the ink roller group. At the same time, the rotation speed control unit 13 issues a print rotation speed reduction command to the printing press driving unit 11, and the rotation speed of the printing press decreases. Next, when a stop command is issued from the roller ink supply stopping means 4, the counter 12 is turned off.
Is started and counted a predetermined number of times or a predetermined time, the plate cylinder ink supply stopping means 8 issues a stop command to the inking roller driving machine 9 to stop the inking roller from the plate cylinder. Similarly, at the timing when the counter 12 further counts and counts the next predetermined number of times or a predetermined time, the printing stop unit 10 issues a stop command to the printing press driving unit, and printing is stopped.

In this embodiment, the roller ink supply stopping means 4 issues a stop command to the ink feeding roller driving means 5, the ink source roller driving means 6, and the ink key opening / closing means 7, but the present invention applies to this. It is not limited. In other words, even if a stop command is issued only to the ink feeding roller driving means 5, the ink supply to the ink roller group can be stopped, and the ink source roller driving means 6 and the ink key opening / closing means 7 can be stopped for the entire printing machine. It may be performed at the time of stop. However, if the ink key is open and the ink source roller is rotating even after the ink feeding roller stops, excess ink will accumulate on the ink source roller, and the ink will flow around the back of the ink key or fall into the printing machine. In order to prevent this, a stop command is issued to the ink source roller driving means 6 and the ink key opening / closing means 7. In this embodiment, the roller ink supply and the plate cylinder ink supply are stopped while the rotation speed of the printing press is reduced. However, the present invention is not limited to this. After the supply is stopped, printing may be stopped by starting to reduce the rotation speed of the printing press.

In the present embodiment, the counter 12 counts based on the issuance of a stop command from the roller ink supply stopping means 4, but the present invention is not limited to this. 4 means for stopping the ink supply of the plate cylinder after counting from the issuance of the stop command 4
May be counted again from when the stop instruction is issued. That is, in the present invention, the roller ink supply stopping means 4, the plate cylinder ink supply stopping means 8, and the printing stopping means 10 only need to operate sequentially with a predetermined number of times or a time interval. You may decide.

The predetermined number of times or the predetermined time in the present embodiment is a numerical value which is determined according to each offset printing press and inputted in advance to the control circuit. That is, the offset printing press has a type (for example, rotary press or sheet-fed press, double-sided or single-sided press, etc.), a design age (for example, how many years the machine is), a maker (design philosophy differs greatly depending on the maker), a setting ( The amount of ink transferred from the blanket to the printing paper and the number of regular rotations vary depending on many factors such as the setting under the blanket, the setting of the thickness of the corresponding paper, the years of use, the maintenance state, the processing speed of the folding machine, and the like. Therefore, the timing of stopping printing for smoothing the film thickness distribution of the ink film on the ink roller group differs depending on the individual printing press. Therefore,
A predetermined number of times or a predetermined time is measured in advance by each printing machine, and the numerical value is input.

FIG. 2 is a flowchart showing the operation of the present invention. In FIG. 2, 21 is a start command, 22 is a stop command input, 23 is a roller ink supply stop, 24 is a count, 25 is a predetermined number count check, 26 is a plate cylinder ink supply stop, 27 is a count, and 28 is a predetermined number count check. , 29 are the printing stop, and 30 is the end.

In FIG. 2, after starting at a start 21, an offset printing stop command is input at a command input 22. Next, roller ink supply stop 23
In, a stop command is issued from the roller ink supply stopping means to the ink feeding roller driving means, the ink source roller driving means, and the ink key opening / closing means 7, and these are stopped. At the same time, a rotation speed control unit (not shown) instructs a reduction in the rotation speed of the printing press. Next, count 2
In step 4, the counter counts the number of times or time from the point of time when the supply of the roller ink is stopped.
At 5, check whether the predetermined count has been made,
judge. If the count has not reached the predetermined count, the counting is further performed. In the plate cylinder ink supply stop 26, a stop command is issued from the plate cylinder ink supply stopping means to the inking roller driving device. Thereafter, counting is performed by the counter in the count 27, and in the predetermined count 28, it is confirmed and determined whether or not the predetermined count is performed. When the count has not reached the predetermined count, the count is further performed.
At printing stop 29, a stop command is issued to the printing press driving means, and the process proceeds to end 30 and ends.

Here, the rotation speed of the printing press will be described. The rotation speed of the printing press gradually decreases from the time of the command input 22. This is because it is difficult to stop the printing press instantaneously and the load on the machine is large, and it is more reasonable to gradually lower the rotation speed and stop the printing press. In addition, since the time required to reduce the number of revolutions and the printing during that time are necessarily required, consuming the ink on the ink roller group during that time means that two operations are performed simultaneously, making the printing operation extremely efficient. It becomes possible to. Note that, in the present invention, the print stop command is a command for finally stopping printing, and does not include a command for reducing the number of rotations.

FIGS. 3A, 3B and 3C are schematic sectional views showing the operation of the printing press according to the present invention. 3 (a), 3 (b) and 3 (c), 31 is a schematic cross section of a printing unit of an offset printing machine, 32 is an ink source roller, 33 is an ink key, 34 is an ink feeding roller,
5 is an ink roller group, 36 is an inked roller, 37
Is a plate cylinder, 38 is a blanket, 39 is printing paper, 40
Denotes an ink fountain, and 41 denotes ink in the ink fountain. 2A, 2B, and 2C are schematic sectional views.
Equipment such as a dampening device is not shown.

FIG. 3A is a sectional view showing a state during printing. In FIG. 3A, the ink 4 in the ink fountain 40 is shown.
In 1, only the amount of the gap between the ink key 33 and the ink supply roller 32 is transferred from the ink supply roller 32 to the ink supply roller 34, passes through the ink roller group 35, and adheres to the plate cylinder 37 via the roller 36 with ink. . Next, the printing is performed by moving from the plate cylinder 37 to the blanket cylinder 38 and onto the printing paper 39. Here, the ink retrieving roller 34 adopts a type that reciprocates between the ink source roller 32 and the ink roller group 35 like a pendulum. However, the present invention is not limited to this. A type in which the ink supply roller 32 and the ink roller group 35 are connected in series to supply ink is also within the scope of the present invention.

FIG. 3B is a cross-sectional view showing a state when the supply of the roller ink is stopped. In FIG. 3B, the ink source roller 32 stops rotating, and the ink roller group 35,
Inking roller 36, plate cylinder 37, bracket cylinder 38
Is rotating, and printing is continued. The ink retrieving roller 34 stops its reciprocating motion in contact with the ink roller group 35, but the ink roller group 3
Since 5 is rotating, it is rotating along with it. In this state, the print image formed on the printing paper 39 is the ink feeding roller 34, the ink roller group 35,
Inking roller 36, plate cylinder 37, bracket cylinder 38
Printing is performed by consuming the ink held thereon, and the amount of consumption per rotation is determined by a printing plate (not shown) on the plate cylinder 37.

FIG. 3C is a sectional view showing a state when the ink supply to the plate cylinder is stopped. In FIG. 3C, the ink roller group 35 stops rotating, the inking roller 36 stops rotating away from the plate cylinder 37, and the plate cylinder 37 and the bracket cylinder 38 rotate. In this case, the consumed ink is the ink on the printing plate and the ink on the blanket.

FIGS. 4 (a), (b), (c) and (d) are conceptual diagrams showing the film thickness distribution of the ink film on the ink roller. In FIG. 4, 51 is an ink roller, 52 is an ink film, 53 is an ink film, 54 is an ink film, and 55 is an ink film.
Is an ink film, 56 is an ink film, 57 is an ink film,
58 is an ink film, 59 is an ink film, 60 is an ink film, 61 is an ink film, 62 is an ink film, 63 is an ink film, 64 is an ink film, 65 is an ink film, 66 is an ink film, and 66 is an ink film. is there.

FIG. 4A is a conceptual diagram showing the film thickness distribution of the ink film on the ink roller during printing. FIG. 4 (a)
2, the ink films 52, 53, 54, and 55 formed on the ink roller 51 each have a thickness corresponding to the printing plate, and form a film thickness distribution corresponding to the printing plate as a whole. The ink film 53 corresponds to the thickest part of the printing plate with a large pattern area, and the ink film 54 corresponds to the thinnest printing plate with a small pattern area.

FIG. 4B is a conceptual diagram showing the film thickness distribution of the ink film on the ink roller after the supply of the roller ink is stopped. In FIG. 4B, the ink films 56, 57, 58, and 59 formed on the ink roller 51 consume the ink amount corresponding to the printing plate. That is,
The ink film 57 corresponding to the portion of the printing plate having a large pattern area consumes the largest amount of ink, and the ink film 58 corresponding to the portion having a small pattern area of the printing plate has the largest amount of ink consumption. Is running low. In addition, ink film 5
6, 59 also consume the ink amount corresponding to the corresponding picture area. The dotted lines indicate the ink films 52, 53, 54,
55 is shown as a reference.

FIG. 4C is a conceptual diagram showing the thickness distribution of the ink film on the ink roller immediately before the stop of the ink supply to the plate cylinder. In FIG. 4C, the ink films 60, 61, 62, and 63 formed on the ink roller 51 have substantially the same thickness, and a smooth ink film thickness distribution with a minimum amount of ink as a whole is obtained. Has formed. When the printing plate consumes the ink according to the pattern area, there is a moment when the film thickness distribution of the ink film on the ink roller becomes smooth as shown in FIG. In the present invention, this point is set as the timing of stopping the ink supply of the plate cylinder ink. In other words, when the film thickness distribution of the ink film on the ink roller becomes smooth, the consumption of the ink on the ink roller is stopped to maintain the state of the film thickness distribution of the smooth ink film. The number of test prints is reduced to a minimum by forming a film thickness distribution corresponding to the print pattern.

FIG. 4D is a conceptual diagram showing the film thickness distribution of the ink film on the ink roller when the ink supply to the plate cylinder is not stopped. In FIG. 4D, ink films 64, 65, 66 formed on the ink roller 51,
In No. 67, the thickness of the ink film is thin, but the smoothness is lost. In other words, if the ink continues to be consumed even after the ink film thickness distribution on the ink roller has become smooth, the ink film thickness distribution will lose its smoothness, and the next print pattern When the corresponding film thickness distribution is formed,
Compared to the prior art, the number of test prints can be significantly reduced, but the number of test prints cannot be minimized.

FIG. 5 is a conceptual graph showing the movement of a conventional printing operation. In FIG. 5, reference numeral 71 denotes the rotation speed which is the Y axis, 72 denotes the elapsed time which is the X axis, 73 denotes the movement of normal printing of the previous item, 74 denotes the movement of stopping the printing press, 75 denotes the movement of preparing the next item, Reference numeral 76 denotes a movement to start printing of the next item, 77 denotes a movement of color adjustment, 78 denotes a movement to improve the rotation speed, 79 denotes a movement of color adjustment, 80 denotes a movement to increase the rotation speed, and 81 denotes a movement of normal printing of the next item. .

In the normal printing movement 73 of the previous item, a printing operation is being performed, and the printed matter is genuine paper (normal printed matter).
Is printed. In the stop motion 74 of the printing press,
The rotation speed is gradually reduced to stop the printing machine,
The printed matter during that period is a waste sheet (defective printing). In the next item preparation movement 75, preparations for the next printing are made, for example, operations such as blanket cleaning, printing plate exchange, and printing paper exchange. In the next item printing start movement 76, printing of the next item is started,
The printing press rises to a low speed, during which the printed matter is broke. In the color adjustment movement 77, the influence of the film thickness distribution of the ink film of the previous item is eliminated, and an ink film having a film thickness distribution corresponding to the next printing plate after replacement is formed on the ink roller group, that is, The opening of the ink key is adjusted so that the printed matter can be printed at the target density. The reason why the number of rotations is small is to minimize the number of damaged sheets. In the operation 78 for increasing the number of revolutions, the number of revolutions approaches the state of normal printing. The printed matter during this time is waste paper, because the density of the printed matter fluctuates depending on the number of rotations. In the color adjustment movement 79, the opening of the ink key is adjusted so that the printed matter can be printed again at the target density. This is because if the rotation speed of the printing press is increased, the density of the printed matter will be affected, so that fine adjustment is performed here to correct it. The printed matter during this time is broke. In the rotation speed increasing movement 80, the rotation speed is increased to the state of normal printing. During this time, the printed matter is treated as waste paper because the density of the printed matter is being checked during this time. In the printing operation 81 of the normal printing of the next item, the printing operation is performed, and the printed matter is printed on regular paper (normal printed matter). It is confirmed that the printed matter is printed at the target density at the point of contact between the rotation speed increasing movement 80 and the normal printing movement 81 of the next item.

In FIG. 5, the movement 7 for starting printing of the next item is described.
6. Broken paper generated during the color tone adjustment movement 77, the rotation speed improvement movement 78, the color tone adjustment movement 79, and the rotation speed improvement movement 80 is combined as a test printing waste sheet. An object of the present invention is to reduce the number of test prints.

FIG. 6 is a conceptual graph showing the operation of the printing operation according to the present invention. In FIG. 6, reference numeral 82 denotes the rotation speed which is the Y axis, 83 denotes the elapsed time which is the X axis, 84 denotes the movement of normal printing of the previous item, 85 denotes the movement of stopping the printing press, 86 denotes the movement of preparing the next item, Reference numeral 87 denotes a movement for starting printing of the next item, 88 denotes a movement for color matching, 89 denotes a movement for improving the rotation speed, and 90 denotes a movement for normal printing of the next item.

In the normal printing movement 84 of the previous item, a printing operation is being performed, and the printed matter is genuine paper (normal printed matter).
Is printed. In the stop motion 85 of the printing press,
The rotation speed is gradually reduced to stop the printing machine,
The printed matter during that period is a waste sheet (defective printing). The waste paper is used to consume ink and form a minimum and smooth ink film thickness distribution on the ink roller group. Here, it is not necessary to consume the ink until the number of rotations becomes zero, and the printing may be stopped by, for example, stopping the supply of paper in the middle, and the ink supply to the plate cylinder may be stopped. By stopping, the consumption of the ink may be stopped (in that case, the paper is consumed). However, if the timing for forming the minimum and smooth ink film thickness distribution on the ink roller group does not overlap with the time of the rotation number 0 and is earlier than that, the printing is stopped or the ink on the plate cylinder is stopped. It is preferable to stop the consumption of the ink by a method such as stopping the supply.

In the next item preparation movement 86, preparations for the next printing are made. For example, blanket cleaning, printing plate replacement, printing paper replacement, etc. are performed. In the next item printing start movement 87, printing of the next item is started, and the printing press starts up to a high rotation speed.
The printed matter during this time is broke. In this case, since the minimum and smooth thickness distribution of the ink film on the ink roller group is formed, for example, the above-described pattern area ratio meter operates extremely effectively, and when the ink key is manually operated. However, since it is sufficient to operate the printer according to the sample printing, the rotation speed can be increased at a stretch. In the color adjustment movement 88, the opening of the ink key is adjusted so that the printed matter can be printed at the target density. This is because if the rotation speed of the printing press is increased, the density of the printed matter will be affected, so that fine adjustment is performed here to correct it. The printed matter during this time is broke. In the movement 89 for increasing the number of revolutions, the number of revolutions is increased to the state of normal printing. During this time, the printed matter is treated as waste paper because the density of the printed matter is being checked during this time. In the normal printing movement 90 of the next item, a printing operation is performed, and the printed matter is a regular paper (normal printed matter). At the point of contact between the rotation speed increasing movement 89 and the normal printing movement 90 of the next item, it is confirmed that the printed matter is printed at the target density.

In FIG. 6, the movement 8 for starting printing of the next item is described.
7. Broken sheets generated during the movement 88 of the color tone adjustment and the movement 89 of the increase in the number of rotations are combined as test-printed lost paper. As is clear from the comparison between FIG. 5 and FIG. 6, the number of test-print lost sheets (the number of test prints) is greatly reduced.

[0051]

EXAMPLE A comparative experiment was conducted between the prior art and the present invention under the following conditions. The experiment was performed using Super Leo Echo (manufactured by Toyo Ink Mfg. Co., Ltd.) on an OK coat (manufactured by Oji Paper Co., Ltd.) using an A horizontal full format offset rotary printing press system 40 (manufactured by Komori Corporation).
Thereafter, the change in print density when printing was performed by changing the printing plate was measured, and a sample of every 20 sheets of the printed matter after the printing plate was changed was measured using a densitometer (X-RITE). I have. The result is shown in FIG.

FIG. 7 is a graph showing a comparison experiment between the prior art and the present invention. In FIG. 7, 100 is a Y-axis, the ratio of the measured density to the target density, 101 is an X-axis, the number of prints, 102 is a density change of a test print after ink consumption according to the present invention, and 103 is a conventional one. This is a change in the density of a test print when ink consumption by the technology is not performed. FIG.
, The density change 102 becomes the target density after printing about 200 sheets, and after the fine adjustment, the density is completely stabilized when it exceeds 1000 sheets, whereas the density change 103 finally reaches the target density at 2500 sheets. Thus, the effect of reducing the number of test prints is clear.

[0053]

According to the first aspect of the present invention, after the ink supply is stopped, printing is performed only with the ink on the ink roller, thereby consuming the ink on the ink roller and the ink on the printing plate. The total amount of ink film on the ink roller group when printing is stopped in the offset printing machine is minimized. Therefore, an ink film having a film thickness distribution corresponding to the printing plate after replacement can be quickly formed, and the number of test prints can be reduced to a minimum. For example, from a printing plate requiring a large amount of ink supply, Even when the printing plate is replaced with a good printing plate with a small amount, the color tone of the printed matter can be adjusted with a small number of test prints. Further, since the total amount of ink on the ink roller group is reduced without collecting the ink in the ink fountain, there is an operational effect that various defects due to the emulsified ink do not occur.

In particular, at the end of printing, a printing plate corresponding to the film thickness distribution of the ink film on the ink roller group is mounted on the plate cylinder. Since the pattern area is large, a large amount of ink can be reduced by performing printing on one sheet, and the operation and effect can be achieved in that the ink can be consumed more efficiently. In addition, when the printing press is stopped, the number of rotations gradually decreases, so all printed matter during that time is lost (defective printing).
However, since the waste paper is effectively used to consume the ink, no extra paper is consumed as compared with the related art, and the operation and effect are extremely efficient. Furthermore, when using a printing plate corresponding to the film thickness distribution of the ink film on the ink roller group to reduce the amount of ink, there is a point in time when the minimum amount of ink becomes the film thickness distribution of the smooth ink film. Therefore, if printing is stopped at this point, that state can be maintained,
On the minimum and smooth film thickness distribution of the ink film, there is an effect that an ink film having a film thickness distribution corresponding to the printing plate after replacement can be formed more quickly.

According to the second aspect of the present invention, after the ink supply is stopped, printing is performed only with the ink on the ink roller, so that the ink on the ink roller is consumed. The ink on the printing plate is minimized, and the ink on the printing plate is also minimized while the total amount of ink on the ink roller group is minimized when printing on the offset printing press is stopped. There is an effect that only a minimal amount of ink remains on the plate, and the printing plate is extremely easily collected. In other words, if a large amount of ink remains on the printing plate, the ink will adhere to other parts, which will hinder removal and transport. If the ink on the printing plate is minimal, this effect should be suppressed. Becomes possible.
In particular, in recent years, automatic plate exchange devices for printing plates have become widespread, and the removal of used printing plates and the setting of the next printing plate have been automatically performed. As a result, the ink of the used printing plate may adhere to the automatic plate changing device and cause a malfunction, but in this case, since the ink is minimized, the probability of the malfunction is reduced. In addition, there is an operational effect that it is possible to reduce the trouble of cleaning for the ink adhesion.

Further, when the ink supply to the plate cylinder is stopped when the film thickness distribution of the ink film on the ink roller becomes smooth, the ink consumption is stopped by stopping the printing as described in the first aspect. The smooth film thickness distribution is held on the ink roller at a more accurate timing as compared with the above. Therefore, an operation and effect can be achieved in that an ink film having a film thickness distribution corresponding to the printing plate after replacement can be formed more quickly on the minimum and smooth ink film thickness distribution.

According to the third aspect of the present invention, the printing or the ink supply to the plate cylinder is stopped at a timing when the plate cylinder is rotated a predetermined number of times after the ink supply to the ink roller group is stopped, so that the precision is further improved. In addition, it is possible to maintain the film thickness of the ink film on the ink roller group in a uniform state. That is, the consumption of the ink on the ink roller group is started from the time when the supply of the ink to the ink roller group is stopped. The amount of consumption is determined by the number of rotations of the plate cylinder (the number of prints). The amount of ink consumed per rotation of the plate cylinder is almost determined by the pattern area of the printing plate and its distribution, and the film thickness distribution of the ink film on the ink roller group is also determined by the pattern area of the printing plate and its distribution. When controlling the ink consumption, it is optimal to control the number of rotations of the printing cylinder (the number of prints). If ink is consumed using a printing plate, a lot of ink is consumed in one rotation of the plate cylinder in a place where the film thickness is thick, and a small amount of ink is consumed in one rotation of the plate cylinder in a place where the film thickness distribution is thin. Therefore, there can be a timing at which the film thickness distribution of the ink film on the ink roller group becomes uniform. If the consumption of the ink is stopped at this timing, the ink having the uniform film thickness distribution with the minimum amount of ink can be obtained. A film can be formed on the ink roller group.When printing after replacing the printing plate, an ink film with a film thickness distribution corresponding to the printing plate after replacement is placed on this minimum and uniform thickness ink film. Quickly formed,
The number of test prints can be reduced to a minimum, and even if a printing plate that requires a large amount of ink supply is replaced with a print plate that requires a small amount, it is possible to adjust the color tone of printed matter with a small number of test prints. The effect is obtained.

Further, when controlling the number of rotations of the plate cylinder, the influence of the rotation speed can be eliminated, and conversely, ink can be consumed while reducing the rotation speed, and printing can be stopped more efficiently. It is possible to do. 500 to 1000 per minute, especially for web offset presses
In the case of a machine that prints about the same number of sheets, even if printing is stopped, it cannot be done instantaneously.Since printing is stopped while reducing the rotation speed, controlling by rotating the plate cylinder consumes ink. This reduces the number of sheets of paper, thereby achieving an effect of further reducing costs.

According to the fourth aspect of the present invention, the printing or the ink supply to the plate cylinder is stopped at a timing when the plate cylinder is rotated for a predetermined time after the ink supply to the ink roller group is stopped. It is possible to make the thickness distribution of the ink films on the group nearly uniform. In other words, the consumption of ink on the ink roller group starts when the ink supply to the ink roller group stops,
This consumption is determined by the number of prints. Since the amount of ink consumed for a single print is largely determined by the picture area of the printing plate, it is best to control the number of prints when controlling the amount of ink consumed. It can be controlled by the number of rotations and the rotation time. In particular, it is difficult to control the number of rotations of the plate cylinder (the number of prints), but if this is controlled over time, it can be easily controlled.
In that case, if it is controlled by the plate cylinder rotation speed and rotation time,
This is close to the case where the number of rotations of the plate cylinder is controlled, but may be managed more simply by time. This is because, in the case of an offset printing press, the printable paper thickness is limited due to the setting of each machine, and therefore, the rotation speed of the printing press is also constant to some extent. Therefore, even if only the time is controlled, it is possible to obtain an effect similar to that obtained by controlling the plate cylinder rotation speed and the rotation time.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a configuration of the present invention.

FIG. 2 is a flowchart showing the operation of the present invention.

FIG. 3A is a cross-sectional view illustrating a state during printing.
FIG. 3B is a cross-sectional view illustrating a state when the supply of the roller ink is stopped. (C) is a cross-sectional view showing a state at the time of stopping the ink supply of the plate cylinder ink.

FIG. 4A is a conceptual diagram showing a film thickness distribution of an ink film on an ink roller during printing. (B) is a conceptual diagram showing a film thickness distribution of the ink film on the ink roller after the roller ink supply is stopped. (C) is a conceptual diagram showing a film thickness distribution of the ink film on the ink roller immediately before the stop of the ink supply to the plate cylinder. (D) is a conceptual diagram showing the film thickness distribution of the ink film on the ink roller when the plate cylinder ink supply is not stopped.

FIG. 5 is a conceptual graph showing the movement of a conventional printing operation.

FIG. 6 is a conceptual graph showing the movement of a printing operation according to the present invention.

FIG. 7 is a graph of a comparative experiment between the conventional art and the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Control means, 2 ... Command input means, 3 ... Command receiving means,
4 ... Roller ink supply stopping means, 5 ... Ink feeding roller driving means, 6 ... Ink source roller driving means, 7 ... Ink key opening / closing means, 8 ... Plate cylinder ink supply stopping means, 9 ...
Ink roller driving means, 10 ... printing stop means, 11
... printing machine driving means, 12 ... counter, 13 ... rotation speed control means, 21 ... start, 22 ... stop command input, 23 ...
Roller ink supply stop, 24: count, 25: confirmation of predetermined number count, 26: plate cylinder ink supply, 27: count, 28: confirmation of predetermined number count, 29: print stop,
Reference numeral 30: End, 31: Schematic cross section of the printing unit of the offset printing machine, 32: Ink source roller, 33: Ink key, 34: Ink retrieving roller, 35: Ink roller group, 36: Ink roller, 37: Plate cylinder, 38 ... blanket, 39 ... printing paper, 40 ... ink fountain, 41 ...
Ink in ink fountain, 51: ink roller, 52: ink film, 53: ink film, 54: ink film, 55
... Ink film, 56 ... Ink film, 57 ... Ink film,
58 ... ink film, 59 ... ink film, 60 ... ink film, 61 ... ink film, 62 ... ink film, 63 ... ink film, 64 ... ink film, 65 ... ink film, 66 ...
Ink film, 67 ... Ink film, 71 ... Y axis rotation speed, 72 ... X axis elapsed time, 73 ... Normal printing movement of the previous item, 74 ... Stopping operation of the printing press, 75 ... Preparation movement, 76: Move to start printing next item, 77: Move to adjust color tone, 78: Move to improve rotational speed, 79: Move to improve color tone, 80: Move to improve rotational speed, 81: Normal printing of next item 82, the rotation speed as the Y axis, 83, the elapsed time as the X axis, 84, the normal printing movement of the previous item, 85
... movement of printing press stop, 86 ... movement of preparation of next item, 8
7: Move to start printing next item, 88: Move to adjust color tone,
89: movement for improving the number of revolutions, 90: movement for normal printing of the next item, 100: ratio of the measured density to the target density on the Y axis, 101: number of prints on the X axis, 102: ink consumption according to the present invention Density change of test print after performing
03: Density change of test print when ink consumption is not performed by the conventional technology

Claims (4)

[Claims] An ink fountain capable of temporarily storing ink, a plate cylinder for printing, an ink roller group for supplying ink from the ink fountain to the plate cylinder, and a film of an ink film on the ink roller. An offset printing method in an offset printing press having an ink key for adjusting a thickness distribution, comprising: inputting an offset printing press stop command after printing of a predetermined number of printed materials, and supplying ink from the ink fountain to the ink roller group after inputting the command. An offset printing method, comprising: stopping and stopping printing of an offset printing machine after stopping supply of ink to the ink roller group. 2. An ink fountain capable of temporarily storing ink, a plate cylinder for printing, an ink roller group for supplying ink from the ink fountain to the plate cylinder, and a film of an ink film on the ink roller. An offset printing method in an offset printing press having an ink key for adjusting a thickness distribution, comprising: inputting an offset printing press stop command after printing of a predetermined number of printed materials, and supplying ink from the ink fountain to the ink roller group after inputting the command. And stopping the ink supply to the plate cylinder after stopping the ink supply to the ink roller group, and stopping the printing of the offset printing machine after stopping the ink supply to the ink roller group. . 3. The timing for stopping printing or the timing for stopping ink supply to the plate cylinder is a timing for rotating the plate cylinder a predetermined number of times after stopping the ink supply to the ink roller group. The offset printing method according to claim 1. 4. The timing for stopping printing or the timing for stopping ink supply to the plate cylinder is a timing for rotating the plate cylinder for a predetermined time after the stop of ink supply to the ink roller group. The offset printing method according to claim 1.