JP2001246733A - Method for adjusting amount of ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for adjusting the amount of ink which smooths the distribution of the ink left in a preceding printing operation when a printing plate is replaced. SOLUTION: In a step S11, the opening of an ink adjusting key having the maximum opening is set up as standard opening Va, the opening obtained by subtracting each opening from the standard opening of each key is obtained, and the opening of the key is set up in a state inverted in relation to the previous opening. In a step S12, the setting value of each part is changed to reduce the amount of ink. In the form of this operation, setting is done to reduce the call frequency of an ink transfer roller in an ink supply means. In a step S13, on the basis of setting in the step S11 and the step S12, printing is done by using unnecessary spoilage sheet. In a step S14, it is judged whether a prescribed number of the spoilage sheets are used for printing or not, and the step S13 is repeated until a necessary number of the sheets are used. In the form of this operation, the amount of ink can be reduced while the distribution of ink on an ink roller is smoothed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the amount of ink in a printing apparatus, and more particularly to a method for adjusting the amount of ink existing along the axial direction of an ink roller when a printing plate is replaced.

[0002]

2. Description of the Related Art In recent years, unlike a general printing apparatus, a printing apparatus having a plate making mechanism for making a printing plate directly on a plate cylinder based on image data has been provided. As such a printing apparatus, there is, for example, a printing apparatus described in JP-A-10-272756, which is generally referred to as a digital printer. Such a digital printing machine is suitable for small-volume printing of many kinds and small quantities, and the printing plate exchange frequency is relatively high.

A general printing apparatus including the above-described digital printing machine is provided with an ink fountain device capable of adjusting an ink supply amount for each of a plurality of regions in a width direction of the printing plate based on an image area of the printing plate. ing. The ink fountain device supplies ink measured for each area to the printing plate via a plurality of ink rollers. In such a printing apparatus, even if the printing plate is replaced, an amount of ink based on the previous printing plate remains on the ink roller. However, there is a problem that the amount of ink does not match the image area.

[0004] In order to solve this problem, Japanese Patent Laid-Open Publication No.
The method disclosed in Japanese Patent Application Publication No. 1-105255 was adopted. This conventional method is a method in which printing is performed using unnecessary paper while the ink supply operation of the ink fountain device is stopped, thereby removing the ink remaining on the ink roller. In this conventional method, after the ink remaining on the ink roller is eliminated by printing using the waste paper, the ink supply amount according to a new printing plate is supplied again.

[0005]

In the above prior art, since ink is actually newly supplied in the next printing, the ink is not completely removed from the ink roller but a small amount of ink is removed. Even if the ink remains, it is sufficient that the distribution of the amount of the ink is smoothed. However, when the remaining ink is removed from the ink roller using the above-mentioned waste paper, since the amount of ink remaining originally differs for each area, a large amount of ink is used until the distribution of the remaining ink becomes naturally smooth. It had to be removed and it took time. In other words, there is a problem that it takes time to start the next operation and also consumes a large amount of waste paper. Therefore, an improvement has been desired especially in a digital printing machine mainly for printing various kinds and small quantities.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide an ink amount adjusting method capable of quickly smoothing an ink amount when changing a printing plate.

[0007]

According to the first aspect of the present invention, a printing plate exchange in a printing apparatus provided with an ink supply means capable of setting an ink supply amount for each of a plurality of areas along an axial direction of an ink roller. It is a method of adjusting the amount of ink at the time,
The ink supply amount V in each area is changed from the constant ink supply amount Va to the ink supply amount V set immediately before in each area.
The ink amount on the ink roller is smoothed by operating the printing apparatus for a predetermined number of times or for a predetermined time, which is set based on the value obtained by subtracting b.

According to a second aspect of the present invention, in the ink amount adjusting method according to the first aspect, the ink supply amount Va
Is set based on one of the maximum values of the ink supply amount Vb.

According to a third aspect of the present invention, in the ink amount adjusting method according to the first or second aspect, the ink supply means includes an ink fountain roller and a plurality of ink adjustment keys abutting thereon. And the number of rotations of the ink discharging roller is reduced during operation of the printing apparatus.

According to a fourth aspect of the present invention, in the ink amount adjusting method according to any one of the first to third aspects, the ink supply means includes an ink fountain means for supplying ink;
An ink transfer roller for intermittently contacting / separating the ink fountain means to take out ink; and, during operation of the printing apparatus, the number of times or the contact time of the ink transfer roller abutting on the ink fountain means. Was reduced.

According to a fifth aspect of the present invention, in the ink amount adjusting method according to the first or second aspect, the ink is supplied from the ink supply means after or before the ink amount is smoothed. The printing apparatus is operated in a state in which is stopped to reduce the amount of ink on the ink roller.

According to a sixth aspect of the present invention, in the ink amount adjusting method according to any one of the first to fifth aspects, the printing apparatus includes image recording means for recording an image on a printing plate on a plate cylinder. The ink supply means controls an ink supply amount based on image data used in the image recording means.

According to a seventh aspect of the present invention, in the ink amount adjusting method according to any one of the first to sixth aspects, the printing apparatus includes a dampening solution supply unit that supplies a dampening solution to the printing plate. The amount of ink on the ink roller is reduced by operating the printing device for a predetermined number of times or for a predetermined time by reducing the supply amount of the dampening solution from a normal amount.

According to an eighth aspect of the present invention, in the ink amount adjusting method according to the seventh aspect, the supply amount of the dampening solution is set within 70% of the dampening solution amount during normal printing.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 is a side view showing an example of a printing apparatus for implementing an ink amount control method according to the present invention, and FIG. 2 is a block diagram of the printing apparatus.

Referring to FIG. 1, a printing apparatus according to the present embodiment includes a first printing unit 1 and a second printing unit 2 capable of performing multi-color printing of two colors each, and printing paper on the first printing unit. A paper feed unit 3 for feeding, an intermediate transport unit 4 for transporting print paper from the first print unit 1 to the second print unit 2, a paper discharge unit 5 for discharging print paper from the second print unit 2, Drive unit 6 which drives the printer synchronously
And

As shown in FIG. 2, each section of the printing apparatus is electrically connected to the control means 7. The control means 7 is composed of a microcomputer having input / output means and storage means (not shown), and controls each section of the printing apparatus in accordance with a predetermined procedure in accordance with an operator's instruction.

On the other hand, the control means 7 is also connected to an external image data creation device 8 such as a DTP (Desk-Top-Publishing) device through a LAN or the like, and receives image data used for printing and performs RIP processing. (Raste
Data processing such as (r-Image-Processing) is performed, and image data is supplied to an image recording unit 12 described later.

The first printing unit 1 has a plate cylinder 10 on its peripheral surface capable of holding printing plates corresponding to two printing areas, and plate supply / discharge means 11 for supplying and discharging the printing plate to and from the plate cylinder.
An image recording unit 12 for forming an image on the printing plate on the plate cylinder 10, a developing unit 13 for developing the printing plate on which the image has been formed, and two dampening solutions for supplying dampening solution to the printing plate. A supply unit 14, two ink supply units 15 for supplying ink to the printing plate, a blanket cylinder 16 having the same diameter as the plate cylinder 10 and abutting on the plate cylinder 10, and a half of the plate cylinder. An impression cylinder 17 having a diameter of 3 mm and contacting the blanket cylinder 16, and a feed cylinder 18 and a discharge cylinder 19 for supplying and discharging printing paper to and from the impression cylinder 17.

The plate cylinder 10 has a pair of gripping means (not shown) for gripping both ends of the printing plate, and the peripheral surface thereof can hold two printing plates corresponding to different colors. It is configured. In addition, by holding one printing plate having two printing areas instead of two printing plates, substantially one printing plate is obtained.
A printing plate for two colors may be provided on one plate cylinder. The plate cylinder 10 is also provided with a position adjusting mechanism (not shown) for adjusting the position of the plate cylinder in the vertical direction (rotation direction of the plate cylinder) and in the horizontal direction (axial direction of the plate cylinder).

The plate supply / discharge means 11 supplies a printing plate to the plate cylinder 10 and collects used printing plates from the plate cylinder 10. The supply cassette temporarily stores the printing plate. Conveying means for removing a printing plate from a supply cassette and supplying the printing plate to the plate cylinder 10;
And discharging means for taking out the used printing plate from 0. (Not shown)

The image recording means 12 forms an image by irradiating the printing plate on the plate cylinder 10 with a light beam. In the present embodiment, the image recording unit 12 includes a beam irradiation unit that performs on / off control of a light beam in accordance with an image signal and irradiates the printing plate with the light beam. Means for sub-scan feed in the direction. As the image recording means 12, other than recording by exposure, other methods such as removal of the recording layer by heat or electric discharge machining, image formation by deterioration, and image formation by ink jet may be employed.

The developing means 13 is composed of a processing liquid tank storing the processing liquid and an application roller arranged partially immersed in the processing liquid. The liquid is pumped up and supplied to the printing plate surface. In this embodiment, each processing liquid tank and coating roller have two sets for developing processing and fixing processing, respectively. Is provided. Note that, depending on the type of printing plate and the image forming method, the developing unit 13 itself may not be necessary.

Two dampening water supply means 14 are provided for one plate cylinder 10, and each dampening water supply means 14 supplies dampening water to a predetermined printing plate on the plate cylinder 10. It is configured as follows. FIG. 3 is a side view showing a main part of one dampening solution supply means 14. In the figure, dampening water supply means 1
4 is a watercraft 30 for storing dampening water, a water source roller 31 immersed in this watercraft and pumping up the dampening water, A water application roller 32 for applying, the water supply roller 31 and the water application roller 32
And a transfer roller 33 for transferring dampening water between the two rollers.

The watercraft 30 is provided with a pump means and a temperature control means, not shown, and is a storage tank for storing dampening water while circulating it at a predetermined temperature. The fountain roller 31 is a rubber roller or a metal roller whose surface is subjected to a hydrophilic treatment, and is rotated in a counterclockwise direction in the figure by a drive motor (not shown). This rotation speed is controlled according to the supply amount of dampening water.

The wet roller 32 is a rubber roller having a hydrophilic surface, and is moved by a cam mechanism (not shown) so as to come into contact with or separate from the plate cylinder 10. It is configured to supply dampening water only to the printing plate. The transfer roller 33 is a hydrophilic rubber or metal roller that comes into contact with the water supply roller 31 and the wet roller 32, and rotates while swinging in the axial direction of the roller by a swinging unit (not shown). By the swing of the transfer roller 33, the dampening solution received from the water supply roller 31 is leveled and transferred to the dampening roller 32.

In the dampening water supply means 14, the amount of dampening water supplied to the printing plate is changed by changing the rotation speed of the water supply roller 31 or the transfer roller 33 and adjusting the nip pressure between the rollers. Can be varied. The relationship between the rotation speed and the like of the water supply roller 31 and the amount of dampening solution supplied has been experimentally obtained in advance and is stored in the storage means in the control means 7.

In FIG. 3, reference numeral 34 denotes a watering roller 3.
2 is a metal rider roller that swingably contacts the roller 2, and is provided to level ink particles mixed on the watering roller 32. The surface of this rider roller is made more mirror-like than the surface of the transfer roller 33, and makes it easier to receive the ink transferred to the watering roller 32. Accordingly, it is possible to prevent the ink particles from traveling along the transfer roller 33 to the watercraft.

The ink supply means 15 is for selectively supplying ink to the printing plate on the plate cylinder 10, and details thereof are shown in FIG. FIG. 4 is a side view showing a main part of one ink supply means 15. In FIG. 4, each ink supply means 15 is capable of supplying an ink amount set for each of a plurality of areas along the width direction of the printing plate, and receives ink fed by the ink fountain means 40. An ink transfer roller 41, a plurality of inking rollers 42 for receiving and transferring ink from the ink transfer roller 41, and an inking roller for receiving ink from the inking roller 42 and applying ink to a printing plate on the plate cylinder 10. 43. FIG.
Then, the inking roller 42 and the ink forming roller 43
Are shown only one each, and the others are omitted. Hereinafter, the rollers of the ink supply means 15 are collectively referred to as ink rollers.

The ink fountain means 40 comprises an ink fountain roller 44 rotatable by a drive means (not shown), and an ink adjusting key 45 arranged close to the surface of the ink fountain roller 44 at a small interval. Ink is stored in an ink groove between the ink supply roller 44 and the ink adjustment key 45. In the ink fountain means 40, the ink adjustment key 45 is
A plurality of ink adjusting keys 45 are moved in the direction toward the ink discharging roller 44 by a driving screw (not shown) or the like to change the gap amount at the minute interval. This makes it possible to adjust the amount of ink fed out for each of a plurality of regions along the axial direction of the ink supply roller 44.

The ink transfer roller 41 is provided with an arm means 46.
A roller arranged to be swingable in the direction of arrow A about the axis 47 by the
Alternatively, it selectively contacts the ink roller 42. Therefore, ink transfer can be performed by intermittently swinging the ink transfer roller 41 between the two rollers.

The inking rollers 42 are a plurality of rollers composed of a metal roller or a rubber roller, and some of the inking rollers 42 are provided with a mechanism for swinging in the axial direction of the rollers. The ink is kneaded by the plurality of inking rollers and transferred to the next ink forming roller 43.

The inking roller 43 is a rubber roller configured to selectively come into contact with or separate from the plate cylinder 10 by a cam mechanism (not shown). The plate can be supplied with ink.

In the ink supply means 15, the ink amount for each area can be adjusted by the amount of advance or retreat of the ink adjustment key 45 of the ink fountain means 40 (generally referred to as the opening of the key). The total amount of ink can also be adjusted by the number of swings of the transfer roller 41 (generally called the number of calls). Note that the relationship between the opening degree of each ink adjustment key and the amount of ink supply is obtained experimentally in advance and is stored in the storage means in the control means 7.

Returning to FIG. 1, the blanket cylinder 16 has the same diameter as the plate cylinder 10, and is provided with a blanket for transferring an ink image to a peripheral surface thereof. Two ink images are transferred from the printing plate on the plate cylinder 10 to this blanket. A blanket cleaning means 20 for cleaning the blanket is provided around the blanket cylinder 16.

The impression cylinder 17 has a half diameter of the plate cylinder 10, and a set of gripping means (not shown) is provided on the peripheral surface thereof. Therefore, on the peripheral surface of the impression cylinder 17, one print sheet having a size corresponding to one print area on the plate cylinder 10 can be held. The gripping means of the impression cylinder 17 opens and closes so as to receive the printing paper from the paper feeding cylinder 18 described later every other rotation and to deliver the printing paper to the paper ejection cylinder 19 described later every other rotation. .

The feed cylinder 18 and the discharge cylinder 19 are
As in the case of the impression cylinder 17, each set has a pair of gripping means (not shown) for holding a printing sheet on its peripheral surface, similarly to the impression cylinder 17. Both the paper feed cylinder 18 and the paper discharge cylinder 19 are rotated in synchronization with the impression cylinder 17, and the phase is set so that the gripping means of each cylinder and the gripping means of the impression cylinder 17 face each other. . The holding means for the paper feed cylinder 18 and the paper discharge cylinder 19 are also provided with the impression cylinder 17.
The opening and closing operation is performed so that printing paper can be supplied and discharged every time the printer rotates twice.

In the first printing unit 1, the plate cylinder 1
0, and based on the difference between the diameter of the blanket cylinder 16 and the diameter of the impression cylinder 17,
When rotated, the impression cylinder 17 rotates twice. Accordingly, when the impression cylinder 17 rotates twice while holding the printing paper, the ink images are transferred from the two printing areas on the plate cylinder 10 onto the printing paper, and two-color printing can be performed.

The configuration of the second printing unit 2 is basically the same as that of the first printing unit 1, so the same reference numerals are given in FIG. 1 and the description is omitted. In the present embodiment, the colors of the ink supplied by the ink supply means 15 of the first printing unit 1 are K (black) and C (cyan), and the color of the ink of the second printing unit 2 is M (magenta). ) And Y (yellow).

The paper feed unit 3 includes a paper feed tray on which print papers are loaded, and separates and takes out only one uppermost print paper from the print papers loaded on the paper feed tray. 18. The operation of separating and supplying the printing paper by the paper supply unit 3 is performed every time the paper supply cylinder 18 rotates every other rotation.

The intermediate transport section 4 transfers printing paper between the discharge cylinder 19 of the first printing unit 1 and the paper feeding cylinder 18 of the second printing unit 2. It is configured. Each transfer cylinder 21 has a diameter twice as large as that of the impression cylinder 17, and two sets of gripping means (not shown) are provided on the peripheral surface thereof. The gripping means of each transfer cylinder 21 and the gripping means of the paper discharge cylinder 19 and the paper feed cylinder 18 are configured so as to be synchronously opened and closed in phases opposite to each other so as to transfer the printing paper. ing.

Since the impression cylinder 17 performs two-color printing every two rotations as described above, when the transfer cylinder 21 having a diameter twice as large as the impression cylinder 17 is used, one set of You may make it provide only a jaw means. That is, in this case, only half of the peripheral surface of each transfer cylinder 21 is used for conveying the printing paper. However, in the printing apparatus of the present embodiment, each transfer cylinder 21 is provided with two sets of gripping means in order to provide a single-sided two-color printing function in which each impression cylinder 17 rotates only once.

The paper discharge unit 5 is composed of an endless chain provided with a gripper for receiving and transporting the print paper from the paper discharge cylinder 19 of the second printing unit 2 and a discharge stand for loading the print paper. Become.

The printing drive unit 6 is composed of a motor for rotating the cylinders of the printing apparatus, and drives a gear (not shown) provided in each cylinder so as to mesh between adjacent cylinders. The torso is driven to rotate synchronously. The sheet feeding operation of the sheet feeding unit 3 is also synchronized with the print driving unit 6 by a synchronization unit (not shown).

In the printing apparatus according to the present embodiment, the first printing unit 1 and the second printing unit 2 can perform multicolor printing of a total of four colors, two colors each. Further, by increasing or decreasing the number of printing units, a two-color printing apparatus or a multi-color printing apparatus having six or more colors can be obtained.

Next, the operation of the printing apparatus will be described with reference to FIG. FIG. 5 is a flowchart showing the entire printing operation. In the figure, first, in step S1, a preparatory operation such as initial setting of each section of the printing apparatus and return to origin is performed. In step S2, an unused printing plate is mounted on the plate cylinder 10 by the plate supply / discharge unit 11. In a printing apparatus in which the plate cylinder 10 holds two printing plates each as in the printing apparatus according to the present embodiment, the above-described step S2 is repeated twice, and each plate cylinder 10 has two unused printing plates. Attach the printing plate.

In step S3, plate making is performed on the printing plate on the plate cylinder 10. That is, the printing plate is exposed by the image recording means 12 based on predetermined image data, and then developed by the developing means 13.

On the other hand, the image data is also used for the adjustment control of the ink amount to be described later. Is calculated. For example, an image area value can be obtained by counting the number of dots in an image area after performing RIP processing on the image data. Further, by subtracting the image area value obtained from the entire area or counting the number of dots in the non-image area, a non-image area value for supplying dampening water can be obtained.

In recent years, an image area value has been calculated based on image data obtained by converting the image data into a predetermined low resolution without using the image data used directly for plate making. In the present invention, such converted image data may be used. The image area calculation may be obtained before starting the plate making operation or the printing operation. Alternatively, it may be obtained by a data processing device or the like outside the printing device.

In step S4, printing is performed. In this printing operation, first, the ink supply amount of the ink supply unit 15 is determined based on the image area value. That is, the degree of opening of each ink adjustment key 45 of the ink fountain means 40 is set, and the number of times the ink transfer roller 41 is called is set. Further, the dampening water supply amount of the dampening water supply unit 14 is determined based on the non-image area value. That is, the number of rotations of the water supply roller 31 and the like are set. Then, dampening water and ink are supplied to the printing plate, and printing paper is sequentially supplied to the impression cylinder 17. When each impression cylinder 17 rotates twice while holding the printing paper, printing of two colors is performed for each printing unit.

At the start of the printing operation, a large amount of dampening solution and a large amount of ink may be required until printing is stabilized. In this case, the printing apparatus may be operated so that the dampening water amount and the ink amount are increased and supplied in accordance with predetermined conditions.

When printing of a predetermined number of sheets is completed in step S4, the printing plate used by the plate feeding / discharging means 11 is discharged in step S5. Then, in step S6, each blanket cylinder 16 is cleaned by the blanket cleaning means 20.

In step S7, it is confirmed whether or not the next printing operation exists. If all printing operations have been completed, in step S8, end operations such as cleaning of the ink supply means 15 and return to the origin of each part are performed. To end the work. If it is confirmed in step S8 that the next printing operation exists, the process returns to step S2 after performing the ink removing operation according to the ink amount adjusting method of the present invention in step S9.

The ink removing operation in step S9 is to print on unnecessary waste paper or the like so as to reduce the amount of ink remaining on each roller of the ink supply device 15, and FIG. This will be described in detail. FIG. 6 is a flowchart showing the procedure of the ink removing operation in step S9 in FIG.

First, in step S11, the reversal adjustment of the ink adjustment key 45 is performed. This adjustment method is described in FIG.
This will be described with reference to FIG. FIG. 7A schematically shows the opening of the ink adjustment key 45 in the printing operation performed earlier, the horizontal axis represents five ink adjustment keys K1 to K5, and the vertical axis represents each ink adjustment key. The opening degree of the keys (corresponding to the ink supply amount) of the keys K1 to K5. In this example, the respective ink adjustment keys K1 and K2 are set to the opening degrees Vb1 to Vb5, respectively. In this example, the number of ink adjustment keys is five for simplicity of explanation.

In the ink supply means 15, since the ink supply amount is determined in accordance with the opening degree of the key, in this example, the ink amount in the printing area corresponding to the ink adjustment key K5 is the largest, and the ink adjustment key K3 Is the least in the printing area corresponding to. Therefore, in a state where the printing operation according to this setting is completed, each of the ink rollers is also approximately in FIG.
The ink remains in a distribution as shown in (A).

In step S11, the openings of the ink adjustment keys K1 to K5 are reversed. First, the opening degree Vb5 of the ink adjustment key K5 having the largest opening degree is set to the reference opening degree V.
Set as a. And for each ink adjustment key Kn,
An opening Vn obtained by subtracting each opening Vbn from the reference opening Va
Ask for. (N = 1-5)

FIG. 7B shows each of the ink adjustment keys K1 to K
5 shows an example in which the respective opening degrees V1 to V5 are adjusted. The opening degree of the key shown in FIG.
3A shows a distribution state inverted with respect to the opening degree of the key shown in FIG. In step S11, as shown in this example, the opening of the ink adjustment key 45 is set to a state in which the opening is inverted with respect to the previous opening.

When the ink is supplied in this state, the supply of the ink amount is small in the region where the amount of the remaining ink is large, and the supply of the ink amount is large in the region where the amount of the remaining ink is small. Can be smoothed. However, in this state, if the ink is supplied in the same manner as during the printing operation, the distribution of the ink amount is smoothed, but the ink amount does not decrease positively. Therefore, in the next step S12, the set value of each section is changed so that the ink amount decreases. In this embodiment, the following two methods are employed, but the present invention can be implemented using only one of them.

First, the ink transfer roller 41
Set to reduce the number of calls. This reduces the amount of ink supplied to each subsequent ink roller,
If the printing is performed on the waste paper, the ink amount on the ink roller is smoothed and decreased.

The other is to reduce the amount of dampening water supplied by the dampening water supply means 14. In this embodiment, this can be achieved by reducing the number of rotations of the water supply roller. As a result, the amount of dampening water on the printing plate decreases, and the amount of ink consumed by printing on the waste paper increases. Therefore, the amount of ink on the ink roller is reduced with smoothing.

However, as a result of experiments conducted by the applicant, if the amount of dampening water is reduced too much, problems such as the printing paper wrapping around the blanket cylinder 16 and the increase of ink mixed in the dampening water occur. I understood. For such defects, the type of ink and printing paper,
Furthermore, although the conditions vary depending on the printing speed, it has been experimentally found that the supply amount of the dampening solution, which is generally appropriate, is preferably 70% or less, and preferably about 90% to 80%.

In step S13, the above-mentioned step S11
Based on the settings in S12 and S12, printing is performed using unnecessary waste paper. In step S14, it is determined whether a predetermined number of sheets have been printed on the waste paper, and step S13 is repeated until the required number of sheets has been reached.

In this embodiment, since the ink supply amount is reduced while the ink supply amount is reversed and the ink amount distribution on the ink roller is smoothed, the ink amount distribution is smoothed earlier than before. Can be

[Other Embodiments] In the above embodiment,
Although the ink amount is reduced while the ink amount is being smoothed, the ink supply may be completely stopped before or after the smoothing to reduce the ink amount.

[0066]

According to the ink amount adjusting method of the present invention, the distribution of the ink amount on the ink roller can be smoothed by an easy procedure, and the preparation for printing on the next printing plate can be prepared.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an example of a printing apparatus that executes an ink amount adjustment method according to an embodiment of the present invention.

FIG. 2 is a block diagram of the printing apparatus.

FIG. 3 is a schematic diagram showing dampening water supply means 14 in the printing apparatus.

FIG. 4 is a schematic diagram showing an ink supply unit 15 in the printing apparatus.

FIG. 5 is a flowchart illustrating a printing operation of the printing apparatus.

FIG. 6 is a flowchart showing a procedure of an ink amount adjusting method according to the embodiment of the present invention.

FIG. 7 is an explanatory diagram for explaining reversal of an ink adjustment key.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st printing unit 2 2nd printing unit 3 paper feed part 4 intermediate conveyance part 5 paper discharge part 6 print drive part 7 control means 10 plate cylinder 11 supply / discharge means 12 image recording means 13 developing means 14 dampening water supply means 15 Ink supply means 16 Blanket cylinder 17 Impression cylinder 40 Ink fountain means 41 Ink transfer roller 43 Ink application roller 44 Ink supply roller 45 Ink adjustment key

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) B41F 33/10 B41F 31/14 AB

Claims (8)

[Claims] 1. A method for adjusting an ink amount when a printing plate is replaced in a printing apparatus including an ink supply unit capable of setting an ink supply amount for each of a plurality of regions along an axial direction of an ink roller, wherein Is constant ink supply amount V
from a, the ink supply amount Vb set immediately before in each area.
A method for controlling the amount of ink on the ink roller by operating the printing apparatus for a predetermined number of times or for a predetermined time, based on the value obtained by subtracting . 2. The method according to claim 1, wherein the ink supply amount Va is set based on any one of the maximum values of the ink supply amount Vb. 3. The ink supply means includes an ink fountain means comprising an ink fountain roller and a plurality of ink adjustment keys contacting the ink fountain roller, and reduces the number of rotations of the ink fountain roller during operation of the printing apparatus. The method according to claim 1 or 2, wherein the ink amount is adjusted. 4. The ink supply means includes an ink fountain means for supplying ink, and an ink transfer roller for intermittently contacting and separating the ink fountain means to take out ink. 4. The ink amount adjusting method according to claim 1, wherein the number of times of contact or the contact time of the ink transfer roller in contact with the ink fountain means is reduced. 5. After or before smoothing the ink amount, a printing apparatus is operated with the ink supply from the ink supply means stopped to reduce the ink amount on the ink roller. 3. The method according to claim 1, wherein the ink amount is adjusted. 6. The printing apparatus includes image recording means for recording an image on a printing plate on a plate cylinder, and the ink supply means controls an ink supply amount based on image data used in the image recording means. The method according to any one of claims 1 to 5, wherein the ink amount is adjusted. 7. The printing apparatus further includes a dampening solution supply unit that supplies dampening solution to the printing plate, wherein the dampening solution supply amount is reduced from a normal amount to a predetermined number of times or for a predetermined time. 7. The ink amount adjusting method according to claim 1, wherein the amount of ink on the ink roller is reduced by operating the printing device. 8. The method according to claim 7, wherein the supply amount of the dampening solution is set within 70% of the dampening solution amount during normal printing.
The method for adjusting the amount of ink described in 1.