JPH1071692A - Table tester of gravure printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure coefficients of dynamic friction and static friction of a doctoring part while simple printing test of gravure printing can be carried out. SOLUTION: A plate cylinder 1, an impression cylinder 2, an ink pan, and a doctor 4 which can be respectively attached and detched are provided. A motor 5 for making the plate cylinder 1 pivot via a rotary shaft 7 connected directly thereto, and a torgue sensor 8 for measuring a torque of the rotary shaft 7 of the plate cylinder 1 are provided. A doctor wherein its swing speed, width and contact angle are variable, and a pressurizing mechanism is provided, is used as the doctor 4. Since its handling property is excellent, a printing test can be carried out while loads of time, labor, etc., are lightened. Dynamic friction force and coefficient of dynamic friction can be measured under a state wherein the impression cylinder 2 is separated from the plate cylinder 1, and only the doctor 4 is made to abut against the plate cylinder 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus used for a gravure printing test for optimizing conditions of a printing drum, a doctor, ink and the like of a doctor ring in gravure printing. The present invention relates to a table test machine capable of performing a laboratory print test without performing a real machine print test.

[0002]

2. Description of the Related Art An example of a printing unit in a conventional gravure printing machine is shown in FIGS. 6 is a schematic front view showing a printing unit of a conventional gravure printing press, FIG. 7 is a perspective view thereof, and FIG. 8 is a schematic front view showing the doctor device of FIG. 6 in an enlarged manner.

In these figures, reference numeral 26 denotes an ink pan, 2
7 is a furnisher roll, 28 is a plate cylinder, 29 is a mount,
Reference numeral 30 denotes a doctor device, 31 denotes an impression cylinder, 32 denotes a plate surface, 33 denotes a cell, I denotes ink, W denotes a web, F denotes an ink contact, and D denotes a doctor contact. The doctor device 30 is attached to the gantry 29 so as to be slidable in the front-rear direction. The doctor device 30 includes an upper doctor holder 34, a lower doctor holder 35, a doctor blade 36, a clamping bolt 37, and a washer 38. Doctor blade 36 interposed between holder 34 and lower doctor holder 35
Is clamped by clamping bolts 37 and washers 38. Although not shown, a mechanical mechanism capable of freely adjusting the position, inclination, and the like of the doctor holder is also provided, and the operator sets various doctor devices in the adjustment work.

[0004] The circulation of ink in a gravure printing machine using such a doctor device 30 is as follows. That is, the ink I in the ink pan 26 is scraped up by the furnisher roll 27, and supplied to the plate surface 32, which is the outer peripheral surface of the plate cylinder 28, at the ink contact point F.
The ink supplied on the upper side 2 rises toward the doctor contact D at substantially the same speed as the plate cylinder 28 rotates. Further, at the doctor contact D, the doctor holder 3
Since the blade edge of the doctor blade 36 held between the plates 4 and 35 is pressed against the plate surface 32, the ink is left in the cells 33 formed on the plate surface 32, and the excess ink on the plate surface 32 is scraped off. Can be Then, the ink clogged in the cells 33 is transferred to the surface of the web W when passing between the plate cylinder 28 and the impression cylinder 31, and printing is performed. The ink scraped off by the blade of the doctor blade 36 drops by the action of gravity, returns to the ink pan 26 below, and is used again for printing.

[0005] In the gravure printing based on the above-described principle, various factors can be considered as factors that hinder the improvement of print quality, and the main factors are doctor streaks and fog defects. To explain these in detail, regarding the doctor streaks, the blade of the doctor blade is partially missing due to the pigment or the like in the ink or foreign matter mixed in the ink, and the doctor blade should originally be scraped off at the missing portion of the blade of the doctor blade. However, it is thought that ink that could not be scraped remains on the plate surface and this is transferred to the printing substrate such as a web, and streaky lines are printed on such defective prints. ing. Next, regarding fogging failure, even if the blade edge of the doctor blade is brought into sliding contact with the plate surface, the ink cannot be completely scraped off for various reasons to be described later, and the ink remains on the plate surface in a thin film form. It is thought to be caused by transfer to a printing substrate such as a web, and such a defective printed material has a thin, for example, blue (color of ink used in a printing unit in which fogging has occurred) as a whole (doctor streak). (Meaning that it occurs not in a line but in a plane) as shown in the figure. here,
The reason why the ink cannot be scraped is that the fogging that occurs during printing, which is called fogging during printing, is caused by the pigment in the ink, etc., and the blade edge of the doctor blade is reduced over time during printing (wear). It is thought that the ink may not be completely removed by the setting of the doctor's pressing pressure, etc. until then, and the fog that occurs from the beginning of printing, which is called the initial fog, is considered. It was thought that the ink was not completely scraped under the setting conditions of the doctor, because the pressure to press the blade of the doctor blade against the plate surface was low, the angle was small, and the material of the doctor blade was not good. Can be

[0006]

As described above,
In gravure printing, doctor streaks, which are the main factors that hinder print quality improvement, and the mechanism by which fogging failures occur are caused by various conditions of the doctor and ink in the doctor ring portion (around the doctor contact D in FIGS. 6 to 8). In addition, it is necessary to reduce the kinetic friction force and the kinetic friction coefficient between the doctor blade and the plate cylinder in order to suppress the wear and chipping of the doctor blade. As one index, it is necessary to optimize the conditions and materials of the plate cylinder, the doctor, and the ink of the doctor ring section (determining the conditions).

However, it is a matter of course that setting these conditions at the time of adjustment work before the start of actual printing is not a good idea because it leads to a longer machine stoppage time. In general, the appropriate conditions are determined in advance. Until now, this printing test was a so-called actual machine test performed on a large printing machine (a wide printing machine used for production printing). However, in this method, during the lunch break, It is unavoidable that the test should be performed at night or on the day when the machine is stopped. It is difficult to schedule a regular test, the burden on the test itself is large, and satisfactory results (appropriate conditions) cannot be obtained. Did not. Regarding the measurement of the kinetic friction force and the kinetic friction coefficient of the doctor ring, which is one of the indices for optimizing the doctor ring conditions, the existing measuring instruments on the market are completely different from the doctor ring mechanism of the actual gravure printing machine. There is no moving mechanism and the pressurizing mechanism is also different), so it could not be an accurate index for optimizing conditions.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to optimize the conditions of the plate cylinder, doctor, ink, etc. of the doctor ring in gravure printing. It is another object of the present invention to provide a gravure printing table test machine capable of performing a gravure printing test and further capable of measuring a dynamic friction force and a dynamic friction coefficient of a doctor ring.

[0009]

In order to solve the above-mentioned problems, a gravure printing table tester according to the present invention is provided.
A motor for rotating the plate cylinder via a rotary shaft directly connected to the plate cylinder, an impression cylinder, an ink pan, and a doctor, each of which includes a detachable plate cylinder, an impression pan, and a doctor, for measuring a torque of the rotary shaft of the plate cylinder; And a torque sensor. As the doctor, a doctor whose swing speed, width and contact angle are variable and which has a pressing mechanism is used. By performing a printing test using this table tester, the dynamic friction force and the dynamic friction coefficient between the doctor and the plate cylinder can be measured.

[0010]

1 is a side view schematically showing a table tester according to the present invention, and FIG. 2 is a perspective view thereof.

As shown in the drawing, the table test machine has basically the same configuration as a conventional printing unit, and includes a plate cylinder 1, an impression cylinder 2, an ink pan 3, and a doctor 4, as shown. As a further characteristic configuration, a motor 6 driven by a power supply 5 is provided, and the motor 6 rotates the plate cylinder 1 via one rotation shaft 7 which is detachably connected directly to the plate cylinder 1. It has become. Numeral 8 denotes a torque sensor for measuring the rotational resistance, which comprises the plate cylinder 1 and the motor 6.
Are connected directly to the rotating shaft 7 and the measurement result is displayed on the meter 9. The doctor 4 can change the doctor contact angle and the type (material such as hardness) of the doctor by exchanging the holder, and the doctor pressing mechanism 10 can arbitrarily set the doctor pressure on the surface of the plate cylinder 1. It has become. The doctor pressing mechanism 10 employs a pressure mechanism such as an air cylinder or a spring capable of freely adjusting the pressure.

By using the above-described table test machine, a print test can be performed on the table test machine without performing a so-called actual machine test, which has been performed on a large printing machine. Specifically, the test ink is put into the ink pan 3, the doctor 4 is brought into contact with the surface of the plate cylinder 1 at a predetermined angle, and the web W is passed between the plate cylinder 1 and the impression cylinder 2, and the raw web W is removed. Printing is performed while pressing with the impression cylinder 2. In this case, conditions such as doctor replacement, doctor pressure, doctor contact angle, and doctor blade material can be changed, and since the plate cylinder 1 is easy to replace, the handleability is good and the burden of time and labor is reduced. A print test can be performed with less. In order to change the ink conditions, the test ink in the ink pan 3 is exchanged (ink condition: type of ink), or a solvent is added to the test ink in the ink pan 3 from the side of the machine (ink condition: concentration and density). (Viscosity) or adding various auxiliaries and lubricants. This test was carried out on the base material of the next item (which may be narrower than the actual machine but uses the same type of web), and the plate cylinder (which may have a smaller number of impositions than the actual machine but with the same pattern) By using a cylinder) and ink (using the same type of ink used in actual production), appropriate doctor conditions and appropriate ink conditions can be obtained.

The measurement of the kinetic friction force or the kinetic friction coefficient is performed by using the impression cylinder 2
Is performed while the doctor 4 is kept away from the plate cylinder 1 and only the doctor 4 is brought into contact with the plate cylinder 1. That is, when a rotational resistance is applied to the plate cylinder 1 by the doctor 4 hitting the plate cylinder 1, the force is picked up by the torque sensor 8, and the dynamic friction force or the dynamic friction coefficient is output to the meter 9. Here, only the doctor 4 is used for the plate cylinder 1
The reason is that the frictional force other than the doctor 4 is not applied to the plate cylinder 1 in order to obtain the dynamic friction coefficient between the doctor 4 and the plate cylinder 1.

FIG. 3 is a side view showing an example of a table tester according to the present invention, and FIG. 4 is a front view thereof.

As shown in the figure, the table tester basically has the same configuration as a conventional printing unit.
One printing unit is integrated in one frame, in which 11 is a motor, 12 is a torque sensor, 13
Is a plate cylinder, 14 is an ink pan, 15 is an impression cylinder, 16 is a doctor, 17 is a printing substrate, 18 is a guide roll, and is a motor 11, a torque sensor 12, and a meter (not shown) for displaying measurement results described above. The relationship is the same as that described with reference to FIGS.

A description will be given of condition setting focusing on fogging suppression in a printing test by the table tester. To determine whether fogging has occurred, the only way is to actually print and check the ink scraping condition. Is mounted with a shaved cylinder (a plate cylinder in which no cell of the pattern is formed). For example, a blue ink is used for the ink, and a transparent film is used for the printing base material 17, and the imprint cylinder 15 is used.
The printing is performed by pressing against the plate cylinder 13. Then, if the appropriate conditions are set, all the blue ink on the peripheral surface of the plate cylinder 13 is scraped off by the doctor 16 and does not transfer to the printing base material 17, so that the printing base material 17 remains permanently transparent. However, if the conditions are not set appropriately, the blue ink that has not been scraped off from the plate cylinder 13 transfers to the printing substrate 17 and the transparent film becomes bluish. Here, the printing substrate 17 has an endless loop in the figure, but this is to emphasize fog which is usually not visible in a single transfer, that is, extremely thin fog occurs in the test. Even if the printing is performed on the endless printing base material 17 many times, fog is transferred to several layers, and finally blue which can be visually observed appears. Therefore, even if you print for a while under conditions that seem to be almost perfect, if slight fog occurs,
With this printing substrate, it is possible to easily confirm the generation of the minute fog.

The printing base material 17 used in the table test machine is endless, but is not limited to this, and a normal web can be used. In this case, in addition to this device configuration, it is necessary to provide a paper feed unit and a paper discharge unit, but the device with such a configuration checks the occurrence of doctor streaks and focuses on the suppression of doctor streaks in the print test. Needless to say, it is suitable for setting conditions. In other words, doctor streaks are generally caused by damage to the cutting edge over time. Doctor streaks are easy to see, and it is impossible to overprint doctor streaks on an endless printing substrate. Because there is.

Further, if the kinetic frictional force or the coefficient of kinetic friction between the doctor and the plate cylinder is determined before passing the printing base material, the test result obtained in the printing test through the printing base material can be determined by the kinetic frictional force or the kinetic friction. The coefficients can be arranged as parameters.

FIG. 5 is a graph showing a measurement example of the dynamic friction force when various inks are used. The horizontal axis represents the printing speed (m / min), and the vertical axis represents the dynamic friction coefficient (μ). From this graph, it can be seen that there is a difference in the dynamic friction coefficient μ due to the difference in the inks (A, B, C). From the measurement results, it was possible to evaluate the performance of the ink during doctoring, and to obtain an index for developing the ink and optimizing the doctoring conditions.

[0020]

As described above, the table tester of the present invention can perform a gravure printing test by using the table tester, and can measure the dynamic friction force and the dynamic friction coefficient of the doctor ring. As a result, it is possible to optimize ink development and doctoring conditions. Therefore, if this table test machine is used, the printing test can be performed under various conditions (doctor blade of a material to be newly adopted, ink of a manufacturer that has not been used so far, newly developed lubricant). Various conditions of the doctor ring that can suppress the occurrence of streaks and fog defects (plate cylinder,
Doctors, inks, etc.), and by setting the conditions on the actual machine based on these appropriate values, it is possible to reproduce almost appropriate conditions on the actual machine, and to perform trial printing (through the base material) until the start of actual printing. , A print test until the start of the actual printing by performing the work including the register adjustment) can be shortened.

Also, for example, the effectiveness of a new lubricant (hereinafter referred to as additive A) can be compared with the case where a conventional lubricant (hereinafter referred to as additive B) is added. That is, under the same doctoring conditions, a printing test was performed in the case where the additive A was added and in the case where the additive B was added, and a comparison was made between the doctor streak and the fog defect. Since it is possible to determine the superiority / deterioration effect of the defect generation suppressing effect, it is effective when a new component (ink, blade, additive, etc.) is adopted.

[Brief description of the drawings]

FIG. 1 is a side view schematically illustrating a table test machine according to the present invention.

FIG. 2 is a perspective view of the same.

FIG. 3 is a schematic side view showing an example of a table test machine according to the present invention.

FIG. 4 is a front view of the same.

FIG. 5 is a graph showing a measurement example of a dynamic friction force when various inks are used.

FIG. 6 is a schematic side view showing a conventional gravure printing unit.

FIG. 7 is a perspective view of the same.

8 is a schematic front view showing the doctor device of FIG. 6 in an enlarged manner.

[Explanation of symbols]

 Reference Signs List 1 plate cylinder 2 impression cylinder 3 ink pan 4 doctor 5 power supply 6 motor 7 rotating shaft 8 torque sensor 9 meter 10 doctor pressing mechanism 11 motor 12 torque sensor 13 plate cylinder 14 ink pan 15 impression cylinder 16 doctor 17 printing base material 18 guide roll

Claims (3)

[Claims] A motor for rotating the plate cylinder via a rotary shaft directly connected to the plate cylinder, an impression cylinder, an ink pan, and a doctor; A gravure printing table test machine, comprising: a torque sensor for measuring torque. 2. The swing speed of the doctor,
The table test machine for a gravure printing machine according to claim 1, wherein a machine having a variable width and a contact angle and having a pressing mechanism is used. 3. The gravure printing table test machine according to claim 1, wherein a dynamic friction force and a dynamic friction coefficient between the doctor and the plate cylinder can be measured.