JPH10315599A - Printing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set a proper boring energy to an environmental change and form stable high-quality print images at all times, by adjusting the boring energy by an energy-adjusting means in accordance with an ink viscosity measured by a viscosity-sensing means. SOLUTION: An energy-adjusting means 130 selects a predetermined boring energy from a preliminarily set boring energy adjustment pattern table in accordance with an ink viscosity detected by a viscosity-sensing means, an ink kind detected by a drum unit sensor 35 as an ink kind-sensing means, and a printing speed set by a printing speed-setting key 47 as a printing speed-setting means. The predetermined boring energy applies a predetermined energy to a heat- generating element of a thermal head 91. The thermal head 91 following an image signal and receiving a power supply from a power source 91E lets the heat-generating element to generate heat in accordance with a power pulse width set at a predetermined value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a printing device such as a stencil printing device.

[0002]

2. Description of the Related Art A thermosensitive digital stencil type stencil printing apparatus is well known as a simple printing apparatus. In this stencil printing machine, a thermoplastic resin film (hereinafter sometimes simply referred to as “film”) is bonded to a Japanese paper fiber or a synthetic fiber as a porous support, or a mixture of the Japanese paper fiber and a synthetic fiber. Using a master having a laminated structure, a film surface of the master is brought into contact with a heating element of a thermal head as plate making means, and the thermal head is operated in a main scanning direction based on image information read by a document reading unit. The film surface of the master is selectively hot-melted to form a perforated image, and the master is moved in the sub-scanning direction with a platen roller, etc. Is automatically wound around the outer peripheral surface of a plate cylinder (hereinafter, sometimes referred to as a “print drum”), and ink is supplied from an ink supply unit inside the plate cylinder. The printing paper fed through the plate-making master is continuously pressed against the plate cylinder by a pressing means such as a press roller, so that ink is released from the opening portion of the printing drum and further from the punching portion of the master. The ink is oozed, and the ink is transferred to a printing paper to perform printing (see, for example, FIG. 19 and JP-A-5-229243).

In such a stencil printing apparatus, an emulsion ink containing a pigment, a resin, a solvent, a surfactant, water and the like is used in many cases. It is known that the viscosity of this emulsion ink greatly depends on the environment due to the temperature and humidity during use and the evaporation of water after being left for a long time. The viscosity of the ink is one of the important characteristics that affect the amount of ink transferred to the printing paper, especially in stencil printing. Depending on the viscosity of the ink, the quality of the printed image, that is, the image density, solid fill, and reverse Various image quality such as transition will be greatly changed. That is, in the general conventional stencil printing apparatus as described above, the viscosity of the ink itself changes greatly depending on the environmental conditions and the leaving time at that time, so that the ink transfer amount to the printing paper also changes, There has been a problem that a stable image quality of a fixed density may not be obtained.

[0004] To cope with the image quality change due to the environmental dependence of the ink viscosity, the perforation energy supplied to the heat generating element of the thermal head is changed in accordance with the ink temperature, so that the image quality change with the environmental condition change. Techniques for reducing the number of pixels have been proposed (for example, see Japanese Patent Application Laid-Open No. 6-320851).

[0005]

However, in the above technique, the viscosity itself of the ink, which fundamentally affects the image quality, is not detected and measured and is not fed back as ink viscosity detection data. In other words, since only indirect detection data is used as a substitute characteristic value of ink viscosity, there may be a case where the setting of perforation energy with a finer grain corresponding to the ink viscosity is not actually performed. There are points.

Further, particularly when the ink viscosity is high, when the printing paper is pressed against the cylindrical plate cylinder by the pressing means, the pressing force is applied to both end regions in the generatrix direction of the plate cylinder. There is a problem that the bleeding of the ink tends to be insufficient compared to the central region, and the image density unevenness may occur on the printing paper.

Accordingly, a first object of the present invention is to solve the above-mentioned problems by using a printing apparatus such as a stencil printing apparatus which operates based on the above-described configuration as conventionally proposed. Directly detects the viscosity change of the ink itself, which is the root cause of the quality change, and further sets the printing speed, ink type (drum type)
It is another object of the present invention to provide a printing apparatus that can set the energy for perforation with a finer grain by combining the information with the above information and obtain a print image of stable quality with little fluctuation with respect to the environment.

A second object of the present invention is to provide a printing apparatus which prevents the occurrence of print density unevenness even when the ink viscosity increases due to a decrease in the operating environment temperature of the printing apparatus.

[0009]

According to a first aspect of the present invention, a master is made by making a heating element of a thermal head generate heat, and the master made by the plate is placed on the outer periphery of a printing drum. A printing device that wraps around the surface, supplies ink to the master on the printing drum, and presses printing paper against the printing drum by pressing means to form a print image on the printing paper. Viscosity detecting means for detecting viscosity, and energy adjusting means for adjusting perforation energy supplied to the heating element of the thermal head to predetermined energy according to the ink viscosity detected by the viscosity detecting means. Features.

According to a second aspect of the present invention, a master is made by making a heating element of a thermal head generate heat, and the master thus made is wound around an outer peripheral surface of a printing drum. In a printing apparatus for forming a print image on the printing paper by pressing the printing paper against the printing drum by pressing means, a viscosity detecting means for detecting the viscosity of the ink, and detecting the type of the ink The perforating energy supplied to the heating element of the thermal head according to a predetermined energy according to the ink type detecting means to be performed, and the ink viscosity detected by the viscosity detecting means and the ink type detected by the ink type detecting means. And energy adjusting means for adjusting the temperature.

According to a third aspect of the present invention, a master is made by making a heating element of a thermal head generate heat, and the master thus made is wound around an outer peripheral surface of a printing drum. In a printing apparatus for forming a print image on the printing paper by pressing the printing paper against the printing drum by pressing means, a viscosity detecting means for detecting the viscosity of the ink, and a type of the ink are set. The perforation energy to be supplied to the heating element of the thermal head according to a predetermined energy according to the ink type setting means to be performed, and the ink viscosity detected by the viscosity detection means and the ink type set by the ink type setting means. And energy adjusting means for adjusting the temperature.

According to a fourth aspect of the present invention, a master is made by making a heating element of a thermal head generate heat, and the master thus made is wound around an outer peripheral surface of a printing drum. And a printing device for forming a print image on the printing paper by pressing the printing paper against the printing drum by pressing means, wherein the printing device has a viscosity detecting means for detecting the viscosity of the ink, The printing speed is variable, the printing speed setting means for selectively setting the printing speed, and the ink viscosity detected by the viscosity detecting means and the printing speed set by the printing speed setting means, An energy adjusting means for adjusting the perforation energy supplied to the heat generating element of the thermal head to a predetermined energy.

According to a fifth aspect of the present invention, a master is made by making a heating element of a thermal head generate heat, and the master thus made is wound around an outer peripheral surface of a printing drum. And a printing device that presses the printing paper against the printing drum by a pressing unit to form a print image on the printing paper, and a viscosity detecting unit that detects a viscosity of the ink, and detects a type of the ink. A printing speed of the printing device is variable; a printing speed setting device for selectively setting the printing speed; an ink viscosity detected by the viscosity detecting device and the ink type; In accordance with the ink type detected by the detecting means and the printing speed set by the printing speed setting means, the drilling air to be supplied to the heating element of the thermal head. And having an energy adjusting means for adjusting the Energy to a predetermined energy.

According to a sixth aspect of the present invention, a master is made by making a heating element of a thermal head generate heat, and the master thus made is wound around an outer peripheral surface of a printing drum. In a printing apparatus for forming a print image on the printing paper by pressing the printing paper against the printing drum by pressing means, a viscosity detecting means for detecting the viscosity of the ink, and a type of the ink are set. A printing speed of the printing device is variable; a printing speed setting device for selectively setting the printing speed; an ink viscosity detected by the viscosity detecting device and the ink type; In accordance with the ink type set by the setting means and the printing speed set by the printing speed setting means, the drilling air to be supplied to the heating element of the thermal head. And having an energy adjusting means for adjusting the Energy to a predetermined energy.

The invention according to claim 7 is the first to sixth aspects of the present invention.
The printing apparatus according to any one of the above, further comprising head temperature detection means for detecting the temperature of the thermal head, the energy adjustment means, taking into account the thermal head temperature detected by the head temperature detection means, It is characterized in that drilling energy is adjusted.

[0016] The invention according to claim 8 is the invention according to claims 1 to 6.
In the printing apparatus according to any one of the above, the pressing force variable means for changing the pressing force of the pressing means against the printing drum, and is set in advance according to the ink viscosity detected by the viscosity detecting means. A predetermined pressing force from the printing pressure control pattern table, and a pressing force variable control means for controlling the pressing force variable means so that the selected predetermined pressing force is applied to the printing drum. It is characterized by having.

According to the ninth aspect of the present invention, there are provided the first to eighth aspects.
In the printing apparatus according to any one of the above, in the print drum, an ink supply unit for supplying the ink to the inner peripheral surface of the print drum is disposed, the viscosity detection unit, An ink viscosity detection roller that contacts the ink application surface of the ink supply means via an ink layer, a roller driving means for rotating the ink viscosity detection roller at a constant rotation speed, and a power supply for supplying power to the roller driving means And a current value detecting means for detecting a current value supplied from the power source to the roller driving means, wherein the viscosity of the ink is detected by detecting a change in the current value.

According to a tenth aspect of the present invention, in the printing apparatus according to any one of the first to eighth aspects, the ink for supplying the ink to the inner peripheral surface of the printing drum is provided in the printing drum. An ink supply unit is provided, the viscosity detection unit includes an ink viscosity detection roller that contacts an ink application surface of the ink supply unit via an ink layer, and rotates the ink viscosity detection roller at a constant rotation speed. Roller driving means, a power supply for supplying power to the roller driving means, and a voltage value detecting means for detecting a voltage value applied to the roller driving means by the power supply, and detecting a change in the voltage value. In this case, the viscosity of the ink is detected.

According to an eleventh aspect of the present invention, in the printing apparatus according to any one of the first to eighth aspects, the ink for supplying the ink to the inner peripheral surface of the printing drum is provided in the printing drum. An ink supply unit is provided, the viscosity detection unit includes an ink viscosity detection roller that contacts an ink application surface of the ink supply unit via an ink layer, and rotates the ink viscosity detection roller with a constant torque. Roller driving means, a constant power supply for supplying a constant power to rotate the roller driving means at a constant torque, and a roller speed detection means for detecting the rotation speed of the ink viscosity detection roller, The viscosity of the ink is detected by detecting a change in the rotation speed of the ink viscosity detection roller.

According to a twelfth aspect of the present invention, in the printing apparatus according to the eleventh aspect, the roller speed detecting means includes an encoder disposed on the ink viscosity detecting roller, and the encoder disposed adjacent to the encoder. And a pulse generator for generating a pulse in cooperation with the pulse generator, wherein the viscosity of the ink is detected based on a change in the pulse generated from the pulse generator.

According to a thirteenth aspect of the present invention, in the printing apparatus according to any one of the ninth to twelfth aspects, the ink supply means includes an ink roller for supplying the ink to an inner peripheral surface of the printing drum. A doctor roller disposed in close proximity to the ink roller, wherein the ink viscosity detection roller is disposed to contact the ink application surface of the ink roller via the ink layer. I do.

According to a fourteenth aspect of the present invention, in the printing apparatus according to the thirteenth aspect, the ink viscosity detecting roller is arranged so that the ink viscosity detecting roller is located downstream of the ink roller in the rotation direction of the ink roller in the vicinity of the ink roller and the doctor roller. It is arranged so as to come into contact with the application surface via the ink layer.

In the printing apparatus according to the first aspect, the energy adjusting means converts the energy for perforation supplied to each heating element of the thermal head to a predetermined energy corresponding to the ink viscosity detected by the ink viscosity detecting means. adjust.

In the printing apparatus according to any one of claims 2 to 6, each of the energy adjusting means may control an individual one of the thermal heads according to the combination of the information parameters (ink viscosity, ink type, printing speed). The drilling energy supplied to the heating element is adjusted to a predetermined energy.

Each of the above energy adjusting means includes:
Specifically, a microcomputer or a microprocessor can be used.

The energy for drilling may be adjusted by changing the width of the energizing pulse to each heating element of the thermal head, or by adjusting the current value or the heating element flowing through each heating element according to the image signal. May be performed by changing the voltage value applied to the.

The minute heating elements arranged in the main scanning direction in the thermal head are of a so-called rectangular type (FIG. 2).
3 (a-4) and (b-4)) also in the heat concentration type (FIG. 23).
(See (a-5)). The heat concentration type is shown in FIG.
As shown in -5), the central portion of the heating element 91a is formed to have a narrow width, the current density is increased in this portion, and heat is concentrated in this portion.

In a stencil printing machine, the image density of a printed image is determined by the amount of ink oozing from the master. The amount of ink that oozes out of the master is proportional to the opening area of each minute hole constituting the perforation pattern formed in the master, and is also proportional to the fluidity of the ink.

Therefore, when the ink is in a high-viscosity state where the ink is hard and has low fluidity, the amount of bleeding due to the low fluidity of the ink can be reduced by enlarging the individual holes forming the perforation pattern. Thus, a printed image having a good image density can be obtained by making up for the increase in the opening area of the hole.
Conversely, when the ink is in a low-viscosity state where the ink is soft and the flowability is high, the size of the individual holes in the perforation pattern is reduced, thereby increasing the amount of bleeding due to the high flowability of the ink, thereby reducing the opening area of the holes. And a printed image with good image density can be obtained.

In other words, in order to obtain a good printed image irrespective of the viscosity of the ink, a perforation pattern may be formed with holes having a size suitable for the viscosity of the ink. That is, the size of the holes in the perforation pattern for obtaining an optimal print image is determined according to each of the ink viscosities.

Referring now to FIGS. 23 (a-3) and 23 (b-3), these figures show a cross section of the structure of a minute heat generating portion in the thermal head. The portion indicated by reference numeral 91A indicates a heating element made of a high electrical resistance material, the portion indicated by reference numeral 91B indicates a lead electrode, and the portion indicated by reference numeral 91C indicates a protective film.

The heating element 91A is formed on a substrate (hatched portion). When a voltage is applied between the lead electrodes 91B, a current flows through the heating elements 91A between the lead electrodes 91B, and the heating elements 91A in the current-carrying portions are caused by Joule heat.
Generates heat.

In the thermal head, such minute heating elements are closely arranged at a constant pitch in a direction (main scanning direction) orthogonal to the drawings (a-3) and (b-3) of FIGS. 23, and the master receives these (a-
3), a punching pattern is formed by melt punching while being conveyed in the left-right direction (sub-scanning direction) of (b-3).

When energy for drilling is supplied to the heating element in the form of electric energy, the energy is converted into thermal energy by the heating element, and the temperature of the master in contact with the protective film 91C rises. The temperature distribution at this time is as shown in (a-2) and (b-2) of FIG. As can be easily understood, FIG. 23 (a-2) shows the case where the perforating energy supplied to the heating element is relatively small, and FIG. 23 (b-2) shows the case where the perforating energy is relatively large. Is the case.

A straight line indicated by a symbol D in the figure is a threshold temperature at which the thermoplastic resin film of the master is melted and perforated, and the master 61 has a diagram corresponding to the magnitude of the perforation energy supplied to the heating element. A small hole as shown in FIG. 23 (a-1) or a large hole as shown in FIG. 23 (b-1) is melt-punched.

In this manner, the size of the hole as one unit of the drilling pattern formed on the master can be controlled by the drilling energy supplied to the individual heating elements of the thermal head. FIG. 23 shows that even if the heating element is rectangular,
The same applies to the heat concentration type shown in (a-5).

As described above, according to each ink viscosity,
The size of the holes in the perforation pattern for obtaining the optimal printed image is determined, while the size of the holes is determined by the energy for perforation. Therefore, the correspondence between the ink viscosity and the energy for perforation to obtain an appropriate printed image Exists, and this correspondence can be determined experimentally.

According to the present invention, based on the correspondence between the ink viscosity and the perforation energy, which has been experimentally determined in advance, the perforation pattern of the holes having such a size that an appropriate printed image can be realized in accordance with the ink viscosity. The drilling energy is adjusted as it is formed.

Most of the heat generated by the heat generating elements in the thermal head is consumed for melting and punching of the master, but a part of the generated heat is also transferred to the thermal head main body and the temperature of the thermal head main body is reduced. To rise.
The above-mentioned temperature rise of the thermal head main body is generally not so large, but when the thermal head operates continuously for a long time, a certain temperature rise cannot be avoided. In such a case, if the energy for perforation is adjusted only by the viscosity of the ink as described above, the heat due to the energy for perforation is added to the temperature rise due to the heat storage of the thermal head main body, and is larger than actually required. Holes may be formed.

In the invention described in claim 7, in consideration of such a point, the perforation energy set according to the ink viscosity or the like is corrected based on the temperature of the thermal head (claim 7). As a specific example of the head temperature detecting means for detecting the temperature of the thermal head, for example, a thermistor can be used. In the current head, it is difficult to measure the temperature of the surface of the heating element of the thermal head. It is desirable that the measurement be carried out (see, for example, FIG. 4 of JP-A-7-241974).

[0041]

Embodiments of the present invention, including embodiments, will be described below in detail with reference to the accompanying drawings. In each of the drawings, each component is omitted as appropriate in order to simplify the drawings. In the drawings, components that are configured as a pair and do not need to be particularly distinguished and described will be replaced with the description by appropriately describing one of them for the purpose of simplifying the description. In describing the shapes of component parts and their arrangement positions, the downstream side in the paper transport direction may be referred to as “front” and the upstream side as “rear”. "Left" (also on the near side of the paper) and "right" on the right side in the paper width direction (also on the far side of the paper). Components having the same shape and function throughout the embodiments and modified examples of the invention described below are denoted by the same reference numerals, and description thereof will be omitted as much as possible.

FIG. 19 shows the overall configuration of a thermosensitive digital stencil printing apparatus to which the present invention is applied.
The overall configuration of the stencil printing apparatus and the stencil printing process will be briefly described. In FIG. 19, reference numeral 50 denotes a main body frame. The main body frames 50 are arranged facing each other on both the left and right sides on the front side and the back side of the paper of FIG. 1 and their thicknesses are exaggerated in FIG. 1 and the like.
As shown in FIG. 19, at the upper part of the main body frame 50,
The portion indicated by reference numeral 80 constitutes a document reading portion, the portion indicated by reference numeral 90 below the plate reading / plate feeding portion, and the portion denoted by reference numeral 101 on the left side of the plate making / plate feeding portion 90 in FIG. The portion indicated by reference numeral 70 on the left side of the print drum 101 in FIG. 1 is a plate discharging unit, and the portion indicated by reference numeral 110 below the plate making / plate feeding unit 90 is a sheet feeding unit and the printing drum 10.
A portion denoted by reference numeral 100 below 1 is a printing pressure portion, and a portion denoted by reference numeral 55 below the plate discharging portion 70 on the left side of the printing pressure portion 100 in FIG.

Next, the operation of the stencil printing apparatus will be described.
This will be described below with reference to FIGS. 3 and 19, including the schematic configuration. First, the operator operates the document reading unit 80.
When a manuscript 60 having an image to be printed is set on a manuscript tray (not shown) arranged above the printer and the master making start key 44 of the operation panel 40 shown only in FIG. 3 is pressed, a master discharging process is executed. You. That is, the printing drum 101 rotates in the direction opposite to the arrow direction A in the figure, and the rear end of the used master 61 mounted on the outer peripheral surface of the printing drum 101 is used as a pair of plate discharging peeling rollers 71a, 71b of the plate discharging unit 70. , The roller pair 71a, 71b rotates and scoops up the rear end of the used master 61 with one of the plate discharging / separating rollers 71b, and the plate discharging roller disposed to the left of the plate discharging / separating roller pair 71a, 71b. The used master 61 is removed from the outer peripheral surface of the printing drum 101 by the plate discharging / conveying device composed of the plate discharging / conveying belt pair 72a, 72b stretched between the pair 73a, 73b and the plate discharging / separating roller pair 71a, 71b. The paper is gradually discharged and discharged into the plate discharge box 74 while being conveyed, and the so-called plate discharge ends. At this time, the printing drum 1
01 continues to rotate counterclockwise. The discharged used master 61 is thereafter compressed inside the stencil discharge box 74 by a compression plate (not shown).

In parallel with the plate discharging process, the original reading section 80 operates to read the original. The detailed configuration and operation related to the document reading are performed by a known “reduced document reading method”, and the document 60 whose image has been read is placed on a document tray (not shown). Is discharged. That is, when reading the image of the original 60, the reflected light from the surface of the original 60 illuminated by the fluorescent lamp 81 while being conveyed on the contact glass (not shown) is reflected by the mirror group 82, passes through the lens 83, and passes through the CCD (CCD). This is performed by causing the light to enter an image sensor 84 composed of a photoelectric conversion element). The electric signal photoelectrically converted by the image sensor 84 is transmitted to an analog / digital (A / D) conversion board (not shown) in the main body frame 50 to be converted into a digital image signal.

The original reading section 80 has a configuration having various functions for color separation necessary for multicolor overprinting, for example, a plurality of color filters described in Japanese Patent Application Laid-Open No. 64-18682 can be switched. A filter unit having the same function and configuration as the controllable filter unit is provided on the optical path between the mirror group 82 and the lens 83, and a detailed description thereof will be omitted.

On the other hand, in parallel with such an original scanning and image reading operation, a plate making / plate feeding process is performed based on digitalized image information. Core tube 61a of master roll 61b wound in a roll around core tube 61a
Is rotatably supported by a rotation support member (not shown) provided in the plate making and plate supplying section 90, and the master 61 is pulled out from the master roll 61b and pressed against the thermal head 91 via the master 61. The master 61 is transported to the downstream side of the master transport path by the rotation of the platen roller 92 and the feed roller pair 93a, 93b at a constant speed. For the master 61 conveyed in this way,
A large number of minute heating elements arranged in a line in the main scanning direction of the thermal head 91 are subjected to various processes by the A / D conversion board and the subsequent plate-making control board (not shown) to be converted into a digital image signal sent. Accordingly, the thermoplastic resin film of the master 61 that selectively generates heat and contacts the heat-generating heating element is melt-punched. In this way,
The image information is written as a punching pattern by the position-selective fusion punching of the master 61 according to the image information.

The leading end of the plate-making master 61c on which the image information is written and made is sent out toward the outer peripheral side of the printing drum 101 by the plate feeding roller pairs 94a and 94b, and the traveling direction is lowered by the guide plate 96. The printing drum 101 in the plate feeding position state (not shown) hangs down toward the expanded master clamper 102. At this time, the used master 61 has already been removed from the printing drum 101 by the plate discharging process.

When the leading end of the master 61c is clamped by the master clamper 102 at a predetermined timing, the printing drum 101 rotates in the direction of arrow A (clockwise) in FIG. 61c is gradually wound. The rear end of the prepressed master 61c is
When the plate 95 is cut to a predetermined length by the cutter 95 after the completion of plate making, and one plate plate-making master 61c is completely wound around the outer peripheral surface of the printing drum 101, so-called plate feeding is completed.

The plate-making master 61c for one plate is used for the printing drum 1
01, the plate making and plate feeding process ends,
The printing process starts. First, the uppermost one of the printing papers 62 stacked on the paper feeding table 51 is the paper feeding roller 111.
The sheet is fed in the sheet conveying direction X indicated by an arrow in the drawing toward the pair of registration rollers 113a and 113b by the pair of separation rollers 112a and 112b.
a, 113b, the printing drum 1 in the printing unit 100 at a predetermined timing synchronized with the rotation of the printing drum 101.
01 and the press roller 103. The press roller 103 is made to be able to freely contact and separate from the outer peripheral surface of the print drum 101 by a press roller displacing means described later, and is fed to the print drum 101 on which the master 61c is wound around the outer peripheral surface. The printing paper 62 has a function as a pressing unit that presses the printing paper 62 to form a print image on the printing paper 62. Then, the fed printing paper 6
2 is inserted between the printing drum 101 and the press roller 103, the press roller 103, which has been separated below the outer peripheral surface of the printing drum 101, is swung and lifted, so that the outer periphery of the printing drum 101 is rotated. It is pressed against the plate-making master 61c wound on the surface. In this way, the prepress master 61c is moved by the adhesive force due to the viscosity of the ink oozing out from the porous portion of the printing drum 101 to the printing drum 101.
At the same time, the master 6
The ink exudes from the perforated pattern portion 1c, and the exuded ink is transferred to the surface of the printing paper 62 to form a printed image.

At this time, on the inner peripheral side of the printing drum 101, ink is supplied from an ink supply distributor 123 to an ink reservoir 122 formed between the ink roller 120 and the doctor roller 121, and
The ink is supplied to the inner peripheral side of the print drum 101 by the ink roller 120 that rotates in the same direction as the rotation direction of the print drum 1 and in synchronization with the rotational speed of the print drum 101 and contacts the inner peripheral surface.

The printing paper 62 on which the print image has been formed in the printing pressure section 100 is peeled off from the printing drum 101 by the paper discharge peeling claw 114 and is sucked by the suction fan 118 while being sucked by the suction discharge inlet roller 115 and the suction discharge. Adsorbed on the conveyor belt 117 stretched over the paper exit roller 116,
Due to the counterclockwise rotation of the conveyor belt 117,
The sheet is conveyed toward the sheet discharge section 55 on the downstream side in the sheet conveying direction X, and is sequentially discharged and stacked on the sheet discharge table 52.

Then, each of the steps of paper feeding, printing and paper discharging is repeated for the set number of prints, and all the steps of stencil printing are completed.

(Embodiment 1) A first embodiment of the present invention (hereinafter, simply referred to as "Embodiment 1") will be described with reference to FIGS. 1 to 14 and FIG. In FIG. 1, the stencil printing apparatus according to the first embodiment includes a printing pressure position where a pressing roller 103 as a pressing means is pressed against the outer peripheral surface of the printing drum 101, and a non-printing position separated from the printing pressure position. A pressing roller displacing means 22 for selectively displacing the printing roller 101, a pressing force varying means 20 for changing the pressing force of the press roller 103 on the printing drum 101 (hereinafter, sometimes referred to as "printing pressure"), and the viscosity of the ink. , A type of ink detecting means (shown in FIG. 4) for detecting the type of ink, and a printing speed setting means (shown in FIG. 3) for selectively setting the printing speed of the stencil printing apparatus. According to the ink viscosity detected by the viscosity detecting means 21, the ink type detected by the ink type detecting means, and the printing speed set by the printing speed setting means, A predetermined drilling energy is selected from the set drilling energy adjustment pattern table, and the energy adjusting means 130 (see FIG. 7) for setting the predetermined drilling energy so as to be applied to the heating element of the thermal head 91. ), A printing pressure control pattern set in advance according to the ink viscosity detected by the viscosity detecting means 21, the ink type detected by the ink type detecting means, and the printing speed set by the printing speed setting means. Select a predetermined pressing force from the table,
Pressing force variable control means 130 for controlling pressing force changing means 20 so that the predetermined pressing force is applied to printing drum 101.
A (shown in FIG. 7). Hereinafter, each of the above configurations will be sequentially described.

The press roller 103 has an inner peripheral portion formed of a core metal and an outer peripheral portion formed of an elastic material such as rubber, and is provided so as to extend in parallel with the axial direction of the printing drum 101. Both ends of the core have a well-known structure in which roller shafts 103a are integrally formed. The press roller displacing means 22 includes a roller shaft 103a on both left and right sides.
The horizontal shaft 3 is provided so as to extend substantially in parallel with each other, and both ends of the horizontal shaft 3 are rotatably supported by a pair of left and right body frames 50 at a predetermined angle. And a pair of left and right arms 2b and 2b rotatably supporting both ends of a roller shaft 103a of the press roller 103 and rotatably supporting a base end thereof at a predetermined angle near both ends of the horizontal shaft 3. Right 2a and press roller 10
Arm and left / right 2 at the approximate center of the horizontal axis 3 and the horizontal axis 3
b, 2a and an intermediate connecting stay 1 for connecting the arm pair left and right 2b, 2a to each other; An upper and lower operating arm 4 for clamping the horizontal shaft 3 at a predetermined angle to the intermediate connecting stay 1 with a small gap, and a base end of which is integrally attached to the horizontal shaft 3 end of the left main body frame 50. A spring mounting arm 5 having a cam follower 5a having a free end swingable about a horizontal axis 3; a printing drum 10 having one end hooked to the free end of the spring mounting arm 5;
A spring 6 for oscillatingly urging the spring mounting arm 5 in a direction to press the press roller 103 against the outer peripheral surface of the spring 1
(Tension coil spring) and a printing pressure cam 18 rotatably supported by the left main body frame 50 with the cam shaft 18a and selectively engaging with the cam follower 5a of the spring mounting arm 5. As described above, since the small gap is provided between the intermediate connecting stay 1 and the vertical operation arm 4, it is possible to adjust the left-right balance of the press roller 103 when the printing pressure is applied. Mechanism and press roller displacement means 2
No. 2 utilizes the so-called "Yajirobe principle".

The intermediate connecting stay 1 is made of a metal having a hollow rectangular cross section. After the intermediate connecting stay 1 is inserted into the arm pair left / right 2b, 2a, a retaining pin (not shown) is driven into the portion close to the outer wall surface of the arm pair left / right 2b, 2a. , The left and right sides in the sheet width direction Y are prevented from falling off. Printing pressure cam 18
Is rotatably supported by the left main body frame 50 with the cam shaft 18a.

The spring mounting arm 5 has a triangular plate shape, and a cam follower 5 a
And selectively engages through the connection. The vertical operation arm 4 and the horizontal shaft 3 are integrally fixed by press-fitting a fixing pin (not shown).

In FIG. 2, reference numeral 150 denotes a press for rotating the printing drum 101 and swinging and displacing the press roller 103 between the printing pressure position and the non-printing pressure position in synchronization with the rotation of the printing drum 101. 4 shows roller driving means. As shown in FIG. 2 only, the press roller driving means 150 is a main motor fixed to the left main body frame 50 for rotating and swinging the print drum 101 and the press roller 103, respectively. 1
51, a speed reducing means 152 interposed between the main motor 151 and the camshaft 18a, and a synchronizing means 157 interposed between the printing drum 101 mounted in the apparatus and the camshaft 18a. Mainly composed.

The deceleration means 152 includes a toothed drive pulley 151b attached to the end of the output shaft 151a of the main motor 151, and a pulley shaft 153 on the left main body frame 50.
a toothed pulley 153 rotatably supported with a
, A toothed belt 155 spanned between the drive pulley 151b and the pulley 153, a small-diameter gear 154 mounted coaxially with the pulley shaft 153a of the pulley 153, and a small-diameter gear mounted coaxially with the camshaft 18a. 154 and a large-diameter gear 156 that meshes.

The synchronizing means 157 is rotatable with the lower pulley 158 having teeth mounted on the cam shaft 18a between the printing pressure cam 18 and the large-diameter gear 156, and the pulley shaft 160a on the left main body frame 50. , A toothed main belt 159 stretched between the lower pulley 158 and the upper pulley 160, and a detachable gear 161 attached to an end of the pulley shaft 160a. Mainly composed.

The lower pulley 158 and the upper pulley 160 have outer peripheral portions with teeth of the same diameter, and are connected and rotated by the main belt 159 so that the respective rotation ratios are 1: 1. It has become. At the time of assembling the apparatus, the printing pressure cam 18 controls the rotation of the printing drum 101 in consideration of the printing pressure range corresponding to the printing portion, which is the opening range of the printing drum 101, and the printing pressure position of the press roller 103. Is fixed to the camshaft 18a. on the other hand,
The left end of the printing drum 101 and a rear frame 101 described later
The drum gear 1 having a same number of teeth as the detachable gear 161 is selectively meshed with the detachable gear 161 on the support shaft 104 between the two.
62 are integrally fixed.

On the other hand, the output shaft 151 of the main motor 151
A slit disk 163 composed of a well-known photo-rotary encoder is attached to a. Slit disk 16
The slit disc 1
A sensor 164 composed of a photo interrupter that sandwiches 63 at a predetermined interval is provided. The rotation speed of the printing drum 101 is detected by detecting a predetermined pulse generated in cooperation with the rotation operation of the slit disk 163 by the rotation drive of the main motor 151 by the sensor 164. Thus, the rotation speed of the print drum 101 is controlled via the main motor 151. A tension roller 165 movably and rotatably supported by the main body frame 50 is provided on the left main body frame 50 near the substantially central portion of the main belt 159. 159.

Here, the operation of the press roller driving means 150 will be briefly described in advance. First, the main motor 1
51 is driven to rotate, so that the drive pulley 151b is driven.
And a pulley 153 via a belt 155 of the speed reduction means 152.
The small-diameter gear 154 and the large-diameter gear 156 are reduced and rotated in this order. The rotation of the large-diameter gear 156 rotates the printing pressure cam 18 and the lower pulley 158 of the synchronization means 157, and further rotates the detachable gear 161 via the main belt 159.
62 is rotated. As described above, the detachable gear 161 and the drum gear 16 of the lower pulley 158 and the upper pulley 160
2 is 1: 1, the printing pressure cam 18 and the printing drum 101 are synchronously rotated at a 1: 1 rotation ratio. When the printing drum 101 is rotated by the driving of the means 150, the large-diameter portion of the printing pressure cam 18 and the cam follower 5a are rotated.
, The press roller 103 is swung and displaced between the printing pressure position and the non-printing position in synchronization with the rotation of the printing drum 101.

The pressing force variable means 20 is fixed to the left main body frame 50 via a member (not shown), and has a worm 15 attached to its output shaft. And is supported so as to be able to advance and retreat only in the front-rear direction in the sheet conveying direction X through a groove (not shown) formed in the left main body frame 50, and has an internal thread at its inner peripheral portion. A worm wheel fixed to the rotating shaft 10 and constantly meshed with a worm 15 is fixedly mounted on the rotating shaft 10, a male screw formed on the outer periphery of the movable shaft 7, which is screwed with a female screw of the movable shaft 7. 11, a rotation speed detection sensor 12 (hereinafter, sometimes simply referred to as “encoder 12”) fixed to one end of the rotation shaft 10 and configured to detect the rotation speed of the worm wheel 11; 0, a pulse detection sensor 13 which is supported via a member (not shown) at a predetermined position and clamps the encoder 12 at a predetermined interval, a shielding plate 8 protruding from the outer peripheral portion of the movable shaft 7, and a left main body frame 50. At a predetermined position via a member (not shown).
And a photo sensor 9 for detecting a home position (a position indicating a standard printing pressure state).

The encoder 12 is a well-known photo encoder having a slit disk, and the rotation speed of the worm wheel 11, that is, the paper transport direction X is determined by the cooperation of the encoder 12 and the pulse detection sensor 13.
, The amount of displacement of the tension of the spring 6 can be detected.

Since the press roller displacement means 22 and the pressing force variable means 20 are configured as described above,
Both ends of the spring 6 are displaceably locked by the free end of the spring mounting arm 5 and the movable shaft 7. Therefore, the rotation amount of the printing pressure control motor 14 is transmitted from the worm 15 to the worm wheel 11 by the forward rotation or the reverse rotation of the printing pressure control motor 14, and further, the paper transport direction X on the movable shaft 7 by the screw mechanism. The movable shaft 7 is moved forward or backward in the sheet transport direction X by the conversion into the linear motion in the forward or backward direction, thereby changing the tension length of the spring 6. Since the tension of the spring 6 is variable, the press roller 10
The printing pressure of No. 3 is changed. In the case of the first embodiment,
The above-described printing pressure control is always started from the home position of the encoder 12 of the pressing force varying means 20.

With reference to FIGS. 1, 2, 4, 14, and 19, the configuration around the printing drum 101, that is, the ink supply means, the ink type detection means, and the viscosity detection means will be described in detail. The print drum 101 is provided to extend in the direction of the support shaft 104, and as shown in a partially enlarged manner in FIG. 14, a large number of fine holes (not shown) having ink permeability are provided. It has a well-known configuration having a two-layer structure of the formed resin or metal porous support cylinder 101a and a plurality of mesh screens 101b wound around the outer peripheral surface thereof. The porous support cylinder 101a is
From a printing part (printable area) in which the opening is formed over a predetermined range on the circumference and an ink-impermeable non-printing part (non-printing area) in which the opening is not formed. Become. The non-printing portion of the printing drum 101 is also formed over both ends of the support shaft 104 in a predetermined range.

In FIG. 1, FIG. 14, and FIG. 19, reference numeral 119 denotes an ink supply means. Ink supply means 119
The ink roller 120 supplies ink to the inner peripheral surface of the printing drum 101, and is arranged in parallel with the ink roller 120 with a minute gap therebetween, and forms an ink pool 122 having a wedge-shaped cross section between the ink roller 120 and the ink roller 120. And an ink supply distributor 123 that supplies ink to the ink reservoir 122. Reference numeral 124 denotes a part of an ink amount detection sensor that detects the amount of ink in the ink pool 122. The known method detects the amount of ink. The ink amount detection sensor 124 is provided with a pressing force variable control unit 130A described below via a drive control circuit or the like.
Is electrically connected to In each of the drawings, the ink pool 122 is shown in a satin pattern.

The configuration around the ink supply means 119 is substantially the same as that shown in FIGS. 2 and 7 of Japanese Patent Laid-Open No. 5-229243, for example. The ink roller 120 and the doctor roller 121 are Support shaft 104
Rotatable to a pair of ink roller side plates (members corresponding to the pair of support plates 61a and 61b in the above-mentioned publication, all of which are omitted in the first embodiment). It is supported by.

This stencil printing apparatus can perform multicolor overprinting of black, red, blue, yellow, and the like, and can easily change colors for each color by replacing the drum unit. For the sake of simplicity, it is assumed that three kinds of inks described below: inks Ak (red), Bk (blue), and Ck (black) are changed in color and multicolor printing is performed. Ink Ak (red), Bk (blue),
As described above, Ck (black) has different fluidities, in other words, different viscosities of the inks, depending on the composition and the amount of the pigment or the like, which is a component contained in the ink.

The printing with the black ink Ck is performed by using the drum unit 140. That is, the drum unit 140 includes the printing drum 1 in which the ink supply means 119 for supplying the black ink Ck is disposed.
01 and a spindle 1 that rotatably supports the printing drum 101
4 and a rear frame 101A and a front frame 101B which are respectively provided at both ends of a long plate-shaped gripping frame 101H shown only in FIGS. 2 and 4 and rotatably support the printing drum 101 via a support shaft 104. , Rear frame 1
01A, a small magnet 30 constituting the ink type detecting means in the first embodiment, and a black ink Ck fixed to the outside of the front frame 101B and supplied to the ink supply distributor 123.
And an ink pump unit (both not shown) for feeding ink.

Similarly, printing with the red ink Ak is performed by using the drum unit 141, and printing with the blue ink Bk is performed by using the drum unit 142. That is, the drum unit 141 includes the ink supply unit 119 for supplying the red ink Ak, the printing drum 101m provided therein, and the ink according to the first embodiment attached to a predetermined position outside the rear frame 101A. Small magnet 31 constituting type detection means
And an ink pump unit and an ink unit piping unit (both not shown), which are fixed outside the front frame 101B and send out the red ink Ak to the ink supply distributor 123, and the like. Has the same configuration as

The drum unit 142 has a blue ink B
and a small magnet 32 that constitutes an ink type detection unit according to the first embodiment and is attached at a predetermined position outside the rear frame 101A.
And an ink pump unit (not shown) and an ink unit piping unit (both not shown) which are fixed to the outside of the front frame 101B and send out the blue ink Bk to the ink supply distributor 123. Has the same configuration as

The left main frame 50 has a bearing support 49 for detachably supporting the support shaft 104 of each of the drum units 140, 141 and 142, and a grip frame 101H.
Each holding means (not shown) for detachably holding the holding member is provided. When the drum units 140, 141, and 142 are mounted on the main body frame 50 of this apparatus, they are attached to the inner wall of the left main body frame 50 at positions opposed to the magnets 30, 31, and 32, respectively. A drum unit detection sensor 35 composed of a group of Hall element sensors 36, 37 and 38 is provided. The drum unit detection sensor 35, together with the three groups of magnets 30, 31, 32 described above,
Of the ink type detecting means in the above. The three Hall element sensors 36, 37, and 38 constituting the drum unit detection sensor 35 are connected to an energy adjustment unit 130 and a pressing force variable control unit 130 via an electronic circuit (not shown).
A is connected.

The holding means and the bearing support 49
The details of the drum unit attaching / detaching mechanism having the same are the same as those described in, for example, Japanese Patent Application Laid-Open No. 5-229243, and a description thereof will be omitted.

By having such an ink type detecting means, for example, the drum unit 140 of black ink Ck can be used.
Is mounted on the main body frame 50, the magnet 30 faces the Hall element sensor 38 of the main body frame 50 and the Hall element sensor 38 is turned on, thereby detecting that the drum unit 140 of black ink Ck is mounted. Is done. Similarly, when the drum unit 141 of the red ink Ak is mounted on the main body frame 50, the magnet 31 opposes the Hall element sensor 36 of the main body frame 50 and the Hall element sensor 36 is turned on. When the drum unit 142 is mounted on the main body frame 50, the magnet 32 faces the Hall element sensor 37 of the main body frame 50 and the Hall element sensor 37 is turned on, so that the drum unit 141 of red ink Ak and the blue ink Bk It is detected that the drum unit 142 is mounted. As described above, at the time of color change printing, the position and the number of the magnets are arranged to be different depending on the number of types of ink (the number of colors of ink in the first embodiment) provided in the drum unit, and By appropriately arranging the Hall element sensors at predetermined positions of the main body frame 50 opposed to them, it is possible to detect the types of ink in a larger number of drums. In addition, as each of the above inks, a W / O emulsion ink is used.

In FIG. 1, reference numeral 21 denotes a viscosity detecting means. As shown in FIGS. 1, 5 and 6, the viscosity detecting means 21
(1) an ink viscosity detecting roller 16 that contacts an ink application surface of the ink roller 120 below the ink roller 120 via an ink layer;
An ink viscosity detection motor 17 as a roller driving means for rotating the ink viscosity detection roller 16 at a constant rotation speed,
It mainly comprises a drive power supply 19 as a power supply for supplying electric power to the ink viscosity detection motor 17, and current value detection means 25 for detecting a current value supplied from the drive power supply 19 to the ink viscosity detection motor 17.

The viscosity detecting means 21 according to the first embodiment
As shown in FIG. 5, the ink viscosity is detected by detecting a change in a current value I supplied from a driving power supply 19 to an ink viscosity detecting motor 17.

The ink viscosity detecting roller 16 has an outer peripheral portion made of an alloy such as aluminum or stainless steel, and is uniformly finished so that the entire outer peripheral surface in the axial direction has a surface roughness within a predetermined range. I have. More specifically, the ink viscosity detecting roller 16 is disposed so as to come into contact with the ink application surface on the downstream side in the rotation direction of the ink roller 120 in the vicinity of the ink roller 120 and the doctor roller 121 via the ink layer. I have. The ink viscosity detecting roller 16 is provided in parallel with the axial direction of the ink roller 120 and extending in the length direction of the ink roller 120. One end of the ink viscosity detecting roller 16 is connected to an end of an output shaft 17a of an ink viscosity detecting motor 17 via a shaft (not shown).
a is rotatably supported on the left ink roller side plate via a bearing (not shown). The other end of the ink viscosity detecting roller 16 is rotatably supported on the right ink roller side plate via a shaft (not shown) via a bearing (not shown). The ink viscosity detecting roller 16 drives the doctor roller 12 by an ink viscosity detecting motor 17.
1 is rotated in the same rotation direction as the rotation direction.

The ink viscosity detecting motor 17 is a DC motor, and is fixed to the outer side wall of the ink roller side plate on the left side. As the driving power supply 19, a DC power supply is used. As shown in FIG. 5, in addition to the drive power supply 19 and the ink viscosity detection motor 17, a method of detecting a change in the current value I supplied from the drive power supply 19 to the ink viscosity detection motor 17 is performed. By providing a reference resistor R as a voltage value conversion means 26 having a closed circuit, a single DC circuit including the driving power supply 19, the ink viscosity detecting motor 17 and the reference resistor R is formed.
The entire configuration of this one DC circuit has a function as one measuring device for measuring a current value I supplied from the driving power supply 19 to the ink viscosity detecting motor 17, and functions as a current value detecting means 25. I do.

A voltage detector 27 for measuring a voltage value (V = IR) generated when a current value I supplied to the ink viscosity detecting motor 17 flows through the reference resistor R is provided between both terminals of the reference resistor R. Is provided. The voltage detector 27 generates a voltage value (V = IR) generated when the current value I supplied to the ink viscosity detection motor 17 flows through the reference resistor R.
Is measured, the change in the current value I is read as a voltage value. The voltage detector 27 has an A / D converter that converts a voltage value as an analog amount into a voltage value as a digital amount.
The converter 28 is connected and the A / D converter 2
The voltage value is converted into a digital signal by 8 to become an ink viscosity detection signal. The A / D converter 28 includes an energy adjustment unit 130 and a pressing force variable control unit 130.
The CPU 131 is connected to the CPU 131 of A and receives the ink viscosity detection signal converted into a digital signal.

The DC circuit shown in FIG. 5 constitutes a part of a drive circuit for driving the ink viscosity detecting motor 17, and the DC power supply 19 supplies the ink viscosity detecting motor based on a command signal from the CPU 131. Needless to say, a semiconductor switching element (not shown) such as a thyristor for controlling on / off of the current supplied to the semiconductor device 17 is provided.

The configuration of the rotation speed control of the ink viscosity detection motor 17 for rotating the ink viscosity detection roller 16 at a constant rotation speed, as shown in FIG. , An encoder 17 provided on an output shaft 17 a of an ink viscosity detection motor 17
E and an ink viscosity detection motor 17 according to a detection value related to the rotation speed unevenness detected by the encoder 17E.
And a constant speed control circuit 23 for controlling the output current value of the drive power supply 19 so as to rotate the ink viscosity detecting roller 16 at a constant rotation speed. The encoder 17E is a magnetic rotary encoder, and is built in the ink viscosity detection motor 17.

The operation of the rotation speed control is as follows. When the rotational speed non-uniformity of the ink viscosity detecting motor 17 (meaning the amount of deviation from the constant rotational speed of the ink viscosity detecting roller 16) is detected by the encoder 17E, the constant speed control circuit 23 controls the ink according to the detected value. The output current value of the drive power supply 19 is controlled so that the viscosity detecting motor 17 rotates the ink viscosity detecting roller 16 at a constant rotation speed, and the output current value is fed back to the ink viscosity detecting motor 17 as needed. With this series of feedback control circuits, it is possible to cause the ink viscosity detection motor 17 to rotate the ink viscosity detection roller 16 at a constant rotation speed.

That is, when the viscosity of the ink is low,
The rotational load torque of the ink viscosity detection roller 16 which is in contact with the ink application surface of the ink roller 120 via the ink layer is reduced, and the rotation speed of the ink viscosity detection motor 17 is increased. Therefore, the output current (voltage) value from the drive power supply 19 decreases. Conversely, when the viscosity of the ink is high, the rotational load torque of the ink viscosity detecting roller 16 increases, and the rotational speed of the ink viscosity detecting motor 17 decreases. The output current (voltage) value from is increased. Therefore, by detecting the change in the current (voltage) value, the change in the ink viscosity can be captured.

The encoder 17E is not limited to the one described above, but may be a rotational speed detection sensor 170 composed of a photorotary encoder having a slit disk, as shown in FIG. 15, and a pulse pinching the slit disk. A well-known sensor including the detection sensor 171 may be used. In this case, the constant rotation speed control of the ink viscosity detection motor 17 is performed by the rotation speed detection sensor 170 and the pulse detection sensor 1.
Ink viscosity detecting motor 17 detected by the cooperation of
Is fed back to the CPU 131 of the energy adjusting means 130 and the pressing force variable control means 130A as needed, and the rotation speed of the ink viscosity detecting motor 17 is controlled at a constant speed.

The constant rotational speed control of the ink viscosity detecting motor 17 is not limited to the above-described one as long as the advantages of the constant rotational speed control need not be desired. Alternatively, it is needless to say that a well-known speed control circuit system using a tacho generator may be used.

Focusing on the above-mentioned contents, among the inks of different ink types, in particular, the red ink A of which color is different
Experiments were performed on three types of ink, k, blue ink Bk, and black ink Ck. As a result, correlation data relating to the ink viscosity and the output voltage of the ink viscosity detection motor as shown in FIG. 11 were obtained.
The output voltage of the ink viscosity detection motor is collectively represented as an ink viscosity detection signal as a signal in the block diagram shown in FIG. In FIG. 11, the voltage detector 27 is shown on the horizontal axis.
Ink viscosity detection motor output voltage V [V] detected by
The vertical axis indicates the ink viscosity η [Pa · s]. The ink viscosity of each color was measured using a cone-plate viscometer (manufactured by HAAKE) at a shear rate of 100.
It is measured in [l / s]. The optimum value of the shear rate at this time may be determined by experiment in accordance with the configuration of the ink viscosity detecting means in the stencil printing apparatus. In this manner, for example, when obtaining correlation data relating to the ink viscosity of an ink at an environmental temperature of 23 ° C. and a relative humidity of 65% and the output voltage of the ink viscosity detection motor, first, a cone plate type viscometer is used. After the measurement, the ink sample having the known ink viscosity is put in the stencil printing apparatus having the structure of the first embodiment under the same environmental conditions, and the ink viscosity is measured in accordance with an operation example shown in a flowchart described later. The detection motor 17 is operated, and an ink viscosity detection motor output voltage V [V] as an ink viscosity detection signal detected by the voltage detector 27 at that time is measured and plotted on a graph.
In this way, the viscosity of the ink changed for each ink depending on the environment, use condition, and the like was measured, and the corresponding ink viscosity detection motor output voltage V [V] was sequentially measured and plotted. The correlation data between the ink viscosity and the output voltage value of the ink viscosity detection motor as shown in the figure was obtained.

As can be seen from the correlation data, it can be said that the ink viscosity η [Pa · s] and the output voltage V [V] of the ink viscosity detection motor are substantially proportional. It should be noted that, for each of the drum units 140, 141, and 142, the specifications such as the shape and dimensions of the ink supply means 119, the ink viscosity detection roller 16, the ink viscosity detection motor 17, and the like, and the arrangement position, etc., were all set identically and measured. Needless to say.

Further, as described above, the output voltage V of the motor for detecting the ink viscosity differs even if the ink viscosity is the same for each type of ink, due to the difference in the composition and the amount of the pigment or the like, which is a component contained in the ink. ing. Therefore, even when the ink type other than the color is different, the ink prescription is different, which supports that the output voltage V of the ink viscosity detection motor is slightly different even if the ink viscosity is the same. Therefore, the setting conditions of the optimum drilling energy and the optimum printing pressure for obtaining the optimum image support that each should be slightly different corresponding to each ink type. For this purpose, it is desirable to set the control conditions of the drilling energy and the printing pressure according to each ink type as in the first embodiment.

It is to be noted that it is expected that it is difficult for current technology to always secure a fixed amount of ink in the ink reservoir 122 in an actual stencil printing apparatus.
After the ink is measured by the doctor roller 121 into an ink layer having a certain thickness on the outer peripheral surface of the ink roller 120, the ink viscosity detecting roller 16 is used for the ink roller which is as close as possible to the inner peripheral surface of the printing drum 101. A configuration was adopted in which the viscosity of the ink in the ink layer on the 120 outer peripheral surface was detected.

As shown in FIG. 3, an operation panel 40 for operating the stencil printing apparatus is arranged above the original reading section 80 of the stencil printing apparatus. On the operation panel 40, an ink type setting key 41 as an ink type setting means not used in the first embodiment, a ten key 42 for setting and inputting the number of prints, and the like, and setting and inputting by pressing (on) the ten key 42 7-segment LED (light-emitting diode) display unit 43 for displaying the input number of prints and the like
A plate making start key 44 for setting and inputting activation of each operation from image reading of a document image to plate feeding; a printing start key 45 for starting a printing operation for the number of prints set and input by the ten keys 42; LED lamp group 46 for displaying the ink type selectively set with the ink type setting key 41 or the ink type detected by the drum unit detection sensor 35, and 5 of the printing speed levels 1 to 5 A speed down key 47A and a speed up key 47B as printing speed setting means for selectively setting one printing speed from among the printing speeds in stages.
Speed setting key 47 and speed down key 47
A speed indicator 48 composed of a group of LED lamps for displaying the set print speed set by the A or the speed up key 47B is disposed.

In the LED lamp group 46, a lamp group that indicates which of three types of inks having different viscosity values of the respective inks is selected, that is, the drum unit 140 corresponding to the black ink Ck is selected. LED lamp 46a indicating that the drum unit 141 corresponding to the red ink Ak has been selected.
LE indicating that the drum unit 142 corresponding to the ED lamp 46b and the blue ink Bk is selected
It comprises a D lamp 46c. Set the ink type setting key 41 to 1
When the ink type setting key 41 is pressed once, the LED lamp 46a is turned on, and when the ink type setting key 41 is pressed twice, the LED lamp 46b is turned on. It is displayed that the drum unit corresponding to the ink type set by the user is selected.

The speed indicator 48 is a speed down key 47A.
Or, by pressing the speed up key 47B each time,
The print speed at which the print speed can be switched to one of five set print speeds from 1 to 5 (hereinafter sometimes simply referred to as “set print speed: first speed to fifth speed”) is displayed. The speed down key 47A or the speed up key 47B is disposed near the speed indicator 48, and each time the key is pressed once, the set printing speed corresponds to any one of the first to fifth speeds. It also has a function of sequentially switching the lighting of each LED lamp, whereby the set printing speed selected by the operator can be visually confirmed on the speed indicator 48.

The hatched “Setting print speed: 3”
The “speed” is a standard printing speed corresponding to a printing speed that is normally used, and is automatically set when the speed down key 47A or the speed up key 47B is not pressed. Here, for example, “set print speed: 1
"Speed" means that the printing speed is the lowest speed of 60 sheets / min: 60 rpm.
In the case of "set print speed: 2nd speed", the print speed is 75 sheets / mi.
n: 75 rpm, “set print speed: 3rd speed” print speed is 90 sheets / min: 90 rpm, “set print speed: 4 speed”
“Speed” means that the printing speed is 105 sheets / min: 105 rpm,
The “set printing speed: 5th speed” is set corresponding to the highest printing speed of 120 sheets / min: 120 rpm, respectively.

Next, the control configuration and control process of the first embodiment will be described in detail with reference to FIGS. In FIG. 7, reference numeral 130 denotes an energy adjusting unit. The energy adjusting means 130 includes a CPU (Central Processing Unit) 131, an I / O (input / output) port and a ROM (Read Only Memory) 132, a RAM (not shown)
It comprises a microcomputer having a (read / write storage device) 133 and the like connected by a signal bus (not shown). Energy adjusting means 13
Numeral 0 is provided on a board (not shown) provided on the left main body frame 50. Note that, in the block diagram shown in FIG. 7, a control configuration surrounded by a broken line represents a control configuration that is not used in the first embodiment.

In the first embodiment, the energy adjusting means 130 serves as an ink viscosity detected by the viscosity detecting means 21, an ink type detected by the drum unit detecting sensor 35 serving as an ink type detecting means, and a printing speed setting means. In accordance with the printing speed set by the printing speed setting key 47, a predetermined punching energy is selected from a preset punching energy adjustment pattern table, and the predetermined punching energy is It has a function of setting so as to be added to the heating element.

The energy for perforation may be adjusted by changing the value of the current flowing through each heating element or the value of the voltage applied to each heating element according to the image signal as described above. In step 1, the change is performed by changing the width of the energizing pulse to the heating element of the thermal head 91. That is,
The energy adjusting unit 130 controls the thermal head 91 by setting an energizing pulse width that allows a hole of an appropriate size to be drilled. The thermal head 91 receives power supply from the power supply 91E according to the image signal, and causes the heating element to generate heat according to the energization pulse width set as described above.

The CPU 131 includes various keys on the operation panel 40, the LED lamp group 46 and the speed indicator 48, the drum unit detection sensor 35, the A / D converter 28, the thermal head 91, the thermistor 91D, and the printing pressure control motor 1.
4 and the pulse detection sensor 13 are electrically connected to each other through the input / output port, and transmit and receive a command signal and / or an on / off signal and a data signal to and from these. Further, the CPU 131 includes a document reading unit 80, a stencil making / plate feeding unit 90, and a stencil discharging unit 7 which constitute the stencil printing apparatus.
0, each of which is electrically connected to each of the driving mechanisms constituting the paper feeding unit 110, the printing pressure unit 100, and the paper discharging unit 55 through respective driving circuits (not shown). Alternatively, it transmits and receives an on / off signal and a data signal, and activates the driving mechanisms of the respective units of the stencil printing apparatus,
It controls the entire operation system such as stop and timing.

ROM 13 in energy adjusting means 130
2 stores in advance a drilling energy adjustment pattern table shown in FIG. 12 which was obtained in advance through experiments and the like as described above. The perforation energy adjustment pattern table is prepared for each corresponding ink type, and the perforation energy adjustment pattern table shown in FIG. 12 is one of the inks.
In the first embodiment, the one related to the black ink Ck is shown.
In the drilling energy adjustment pattern table, the output voltage value [V] of the ink viscosity detection motor is plotted on the horizontal axis, and the energizing pulse width corresponding to this is plotted on the vertical axis. Speed: The first speed, the third speed, and the fifth speed are assigned so as to step up in steps. That is, the drilling energy adjustment pattern table uses the ink viscosity detection motor output voltage [V], which is the detected value of the viscosity of the black ink Ck, and the set printing speed as parameters, in other words, the ink viscosity detection signal and the printing speed setting signal. , The predetermined energizing pulse width is determined. The ROM 132 stores in advance programs relating to operations such as starting, stopping, and timing of the above-described units, programs relating to operations of the energy adjusting unit 130 that execute the above functions, or necessary data. It should be noted that the above-described three-step setting printing speed is merely an example of a typical setting example, and the setting printing speed: second speed and fourth speed are omitted for convenience of explanation.

RAM 13 in energy adjusting means 130
Reference numeral 3 inputs and outputs setting parameters by temporarily storing the calculation results of the CPU 131 and storing data signals and on / off signals set / input from the various keys and the sensors as needed.

In FIG. 7, reference numeral 130A denotes a pressing force variable control means. Like the energy adjusting means 130, the pressing force variable control means 130A includes a CPU (Central Processing Unit) 131, an I / O (input / output) port and a ROM (read-only storage device) 132 (not shown), and a RAM (read-write memory). A storage device) 133 and the like, which are connected by a signal bus (not shown).

In the first embodiment, the pressing force variable control means 130A sets the ink viscosity detected by the viscosity detecting means 21, the ink type detected by the drum unit detection sensor 35 as the ink type detecting means, and the printing speed setting. In accordance with the printing speed set by the printing speed setting key 47 as a means, a predetermined pressing force is selected from a preset printing pressure control pattern table, and the predetermined pressing force is applied to the printing drum 101. Thus, the function of controlling the pressing force varying means 20 is provided.

ROM1 in pressing force variable control means 130A
32 stores in advance a printing pressure control pattern table shown in FIG. The printing pressure control pattern table is prepared for each type of the corresponding ink. The printing pressure control pattern table shown in FIG. 13 is one of the inks, and the black ink Ck in the first embodiment. Are shown. In this printing pressure control pattern table, the output voltage value [V] of the ink viscosity detection motor is plotted on the horizontal axis, and the printing pressure setting [N] most suitable for the machine conditions at that time and the printing pressure setting pulse number corresponding to this are displayed vertically. The printing speed is set in three stages to correspond to these: 1st speed, 3rd speed,
The fifth gear is assigned so as to step up in a stepwise manner. In other words, the printing pressure control pattern table uses the ink viscosity detection motor output voltage [V], which is the detection value of the viscosity of the black ink Ck, and the set printing speed as parameters, in other words, the ink viscosity detection signal and the printing speed setting signal. , The number of printing pressure setting pulses corresponding to the predetermined pressing force, that is, the setting printing pressure [N] most suitable for the mechanical conditions at that time is determined. Also, ROM
132 stores in advance a program (see the flowcharts of FIGS. 8 to 10) relating to the operation of executing the above function of the pressing force variable control means 130A. It should be noted that the above-described three-step set printing speed is merely an example of a typical setting example, and the set printing speed:
The second and fourth speeds are omitted for convenience of explanation.

Each signal generated by pressing (turning on) various keys, that is, a plate making start signal from the plate making start key 44, a print start signal from the print start key 45, a print number signal from the numeric keypad 42, and printing. A print speed setting signal (data signal or on / off signal) from the speed down key 47A or the speed up key 47B of the speed setting key 47 is sent to the CPU 131 via the input port.
Respectively. The CPU 131 captures the print speed setting signal, and outputs a speed display signal (on / off signal) for turning on an LED lamp related to the set print speed based on the print speed setting signal, based on the output port and the drive circuit (not shown). And the print speed setting signal is temporarily stored in the RAM 133. The ink type detection signal (on / off signal) detected by the drum unit detection sensor 35 is transmitted to the CPU 131 via the input port. CPU 131
Captures the ink type detection signal, and sets each LED of the LED lamp group 46 based on the ink type detection signal.
An ink type display signal for turning on the lamp is transmitted to the LED lamp group 46 via the output port and a driving circuit (not shown), and the ink type detection signal is transmitted to the LED lamp group 46.
For example, it is temporarily stored in M133.

As described with reference to FIGS. 5 and 6,
The ink viscosity detection signal converted to a digital signal by the A / D converter 28 is supplied to the CPU 13 via the input port.
1 is sent. The CPU 131 compares the ink type detection signal, the printing speed setting signal, and the ink viscosity detection signal with a perforation energy adjustment pattern table stored in the ROM 132 in advance,
Control is performed so that predetermined drilling energy is applied to the thermal head 91. Further, the CPU 131 performs a comparison with a printing pressure control pattern table stored in the ROM 132 in advance based on the ink type detection signal, the printing speed setting signal, and the ink viscosity detection signal, and determines a predetermined pressing force, that is, The number of printing pressure setting pulses corresponding to the setting printing pressure [N] that is most suitable for the mechanical conditions is determined, and the printing pressure control signal relating to the number of printing pressure setting pulses is output to the output port and the drive circuit (not shown). The print data is transmitted to the print pressure control motor 14 via the control unit to perform optimal print pressure control.

(Operation of the First Embodiment) Next, the operation of the stencil printing machine shown in FIG. 19 will be described focusing on the differences from the above-described operation while also using the flowcharts of FIGS. First, when the operator sets the original 60 on the original receiving tray and then presses (turns on) the plate making start key 44, a plate making start signal is input and taken into the CPU 131 of the energy adjusting means 130 through the input port. When the plate making start signal is input to the CPU 131, the ink type of the drum unit 140 is detected. That is, when the Hall element sensor 38 of the drum unit detection sensor 35 is opposed to the magnet 30 of the drum unit 140 and the Hall element sensor 38 is turned on, it is detected that the drum unit 140 of the black ink Ck is surely mounted. . Then, the ink type detection signal is transmitted to the CPU of the energy adjusting unit 130.
131 is input and taken in via the input port,
The energy setting for drilling is temporarily stored in the RAM 133,
This is one condition of the printing pressure control. At the same time, LED
When the LED lamp 46a of the lamp group 46 is turned on,
The operator visually confirms that the drum unit 140 of the black ink Ck is mounted. Next, the above-described plate discharging process is performed (steps S1 to S3).
reference).

Next, after the operator sets the number of prints with the numeric keypad 42 and presses the speed up key 47B of the print speed setting key 47 to select the set print speed: 5th, the print number setting signal and the print speed setting are set. The signal: the fifth speed is sequentially taken into the CPU 131 of the energy adjusting means 130 via the input port, and is temporarily stored in the RAM 133 in the same manner as in the case of the ink type detection signal, for setting the energy for punching and controlling the printing pressure. Condition. Then, in accordance with a command from the CPU 131, the numerical value of the number of prints is displayed on the LED display section 43, and the LED lamp of the speed indicator 48 corresponding to the set print speed: fifth speed is turned on (see steps S4 and S5). .

Then, the process proceeds to a step S6, wherein the printing drum 1
01 is rotated idling in the direction of arrow A in the figure. At the same time as the rotation of the printing drum 101, the ink roller 120
Are also synchronously rotated in the same direction, and the ink amount detection sensor 12
When the amount of ink in the ink reservoir 122 is detected by the operation of 4, the ink supply pump is operated, and the ink Ck is supplied from the ink supply distributor 123 until a predetermined amount is reached. When the ink amount detection sensor 124 detects that the ink Ck in the ink pool 122 has reached a predetermined amount, the ink viscosity detection motor 1
7 is the doctor roller 1 at a constant rotation speed as described above.
21 is driven to rotate in the same direction as the direction of rotation.

As described with reference to FIGS. 5 and 6,
If the viscosity of the ink Ck is low, the ink roller 120
The rotation load torque of the ink viscosity detection roller 16 which is in contact with the ink application surface of the ink via the ink layer is reduced, and the rotation speed of the ink viscosity detection motor 17 is increased. The current value I flowing from 19 into the ink viscosity detection motor 17 decreases. Conversely, when the viscosity of the ink Ck is high, the rotational load torque of the ink viscosity detecting roller 16 becomes large, and the rotational speed of the ink viscosity detecting motor 17 becomes slow. The current value I flowing from the power supply 19 to the ink viscosity detection motor 17 increases. This current value I is converted into a voltage value by a voltage value conversion means 26 of a current value detection means 25, and this voltage value is detected by a voltage detector 27, and is converted into a digital signal by an A / D converter 28 to detect ink viscosity. Energy adjustment means 1 as a signal
The CPU 131 is input / taken in via the input port (see step S7).

When the ink viscosity detection signal is received by the CPU 131, the process proceeds to step S8, where the CPU 131
Reads the above-mentioned ink type detection signal from the RAM 133 and performs a comparison with the perforated energy adjustment pattern table for each color stored in the ROM 132 in advance.
First, a perforation energy adjustment pattern table for the ink Ck shown in FIG. 12 is selected. And C
The PU 131 is shown in FIG. 12 with the ink viscosity detection signal (the output voltage value of the ink viscosity detection motor in the first embodiment) and the print speed setting signal (set print speed: 5 speed) called from the RAM 133. A comparison is made with the drilling energy adjustment pattern table relating to the ink Ck being used, and a predetermined drilling energy (energization pulse width) is determined.
Is set (step S9).

An example of setting the predetermined energizing pulse width is as follows. In other words, for example, when the ink viscosity detection signal ink viscosity detecting the motor output voltage value V is less than V ₂ or V _3, the printing speed setting signal is represented by a black thick line = set printing speed: in response to 5-speed, energized PW _{+ 1} is set as the pulse width. As other examples, when the ink viscosity detection signal ink viscosity detecting the motor output voltage value V is V ₃ or greater, PW ₊₃ as energizing pulse width
Is set.

Then, the process proceeds to a step S10, where the plate-making master 61c is supplied to the printing drum 101.

On the other hand, the ink viscosity detection signal is
When the data is captured by the CPU 31, the process proceeds to step S11 and the CPU
131 calls up the ink type detection signal from the RAM 133 and compares it with the printing pressure control pattern table for each color stored in the ROM 132 in advance.
The printing pressure control pattern table for the ink Ck shown in FIG. 13 is selected. Then, the CPU 131 outputs the ink viscosity detection signal (in the first embodiment, the output voltage value of the ink viscosity detection motor) and the printing speed setting signal (set printing speed: 5) called from the RAM 133.
Speed) and the printing pressure control pattern table for the ink Ck shown in FIG. 13 are compared, and a predetermined printing pressure setting pulse corresponding to the printing pressure (setting pressing force) most suitable for the machine conditions at that time Determine the number.

An example of determining the predetermined number of printing pressure setting pulses is as follows. That is, for example, the output voltage value V of the ink viscosity detection motor is V ₂ as the ink viscosity detection signal.
The time of less than V _3, the printing speed setting signal = set printing speed is represented by a black thick line: in response to 5-speed, optimum settings printing pressure to mechanical conditions in the [N] is P ₊₁ [ N] is selected, and PL ₊₁ is determined as the printing pressure setting pulse number corresponding to the set printing pressure P ₊₁ [N]. As other examples, when the ink viscosity detection signal ink viscosity detecting the motor output voltage value V is V ₃ or greater, most suitable set printing pressure to mechanical conditions in the [N] is P ₊₃ [N] And the number of printing pressure setting pulses corresponding to the set printing pressure P ₊₃ [N] is P
L _{+ 3} is determined.

Next, the routine proceeds to step S12, where the printing pressure setting processing operation shown as a subroutine program in FIG. 10 is executed. In the printing pressure setting processing operation, first, in step S13, the encoder 12 in the printing pressure standard state is operated in cooperation with the shielding plate 8 and the photo sensor 9.
Is detected, the pulse number signal corresponding to the standard printing pressure state is input to the CPU 131 and captured. Thereafter, the CPU 131 controls the printing pressure control motor 14 to print a printing pressure control signal (command signal) for rotating the encoder 12 by the predetermined number of printing pressure setting pulses via the output port and the drive circuit. Output and transmit to pressure control motor 14. On the basis of the printing pressure control signal, the printing pressure control motor 14 starts to be driven forward or reverse until the encoder 12 reaches the predetermined printing pressure set pulse number (encoder pulse number).
The rotation speed of the encoder 12, that is, the displacement amount of the tension length of the spring 6 is input / taken into the CPU 131 as a pulse number signal and feedback-controlled by the cooperation of the pulse detection sensor 13 with the pulse detection signal 13 as needed. And CPU
At 131, when it is determined that the pulse number signal from the pulse detection sensor 13 is equal to the predetermined printing pressure set pulse number, the output of the printing pressure control signal to the printing pressure control motor 14 is stopped. The rotational drive of the printing pressure control motor 14 is stopped (steps S14 to S14).
16).

The tension of the spring 6 is changed by the displacement of the tension length of the spring 6 corresponding to the predetermined printing pressure setting pulse number (encoder pulse number). A pressure control operation is performed. Next, the routine proceeds to step S17, where it is determined whether or not the printing pressure setting operation is OK. For this determination, for example, in the case of the first embodiment, a method of actually measuring the tension or the length of the spring 6 can be considered. However, since the configuration becomes complicated and the cost increases,
Not a good idea. Thus, in the first embodiment, a method of simply determining whether or not the shielding plate 8 is detected is used. Then, in step S19, the print start key 45 is pressed by the operator, and then the process proceeds to step S20, in which the normal print processing operation for the number of prints set and input by the ten keys 42 is performed, and a series of operations is completed. (See steps S20 to S21).

Here, with reference to FIG. 14, printing conditions for obtaining a print image of optimal quality will be briefly described. In the printing by the stencil printing machine as described above, the stencil master 6 is used.
The amount of ink pushed out from the perforated portion 1c is determined by the ink roller 120 and the printing drum 101 of the ink supply means 119.
Is affected by the contact pressure F (also the ink discharge pressure F) with the porous support cylindrical body 101a inside. The ink discharge pressure F is applied to the printing drum 10 by the press roller 103 (or an impression cylinder 125 as a pressing means to be described later) via the press roller displacement means 22 and the pressing force variable means 20 described above.
1 is not the printing pressure P itself, but a value obtained by subtracting the force for deforming the printing drum 101 and bringing the printing drum 101 into contact with the ink roller 120. Is also a small value (P> F). Therefore, in order to set the ink discharge pressure F as one of the printing conditions for obtaining a print image of optimum quality to an optimum value, the rigidity of the printing drum 101 and the press roller 103
It is necessary to balance the printing pressure P with the printing pressure P.

If the viewpoint is changed, it is necessary to apply pressure to the surface of the printing paper 62 having irregularities when microscopically viewed, to push the ink, and to further penetrate the ink into the fibers of the printing paper 62. It is also important to control the printing pressure P for pressing the printing paper 62 against the plate-making master 61c in addition to the ink ejection pressure F which is the pressure for pushing out the ink from the inside of the printing drum 101, in order to obtain a print image of optimal quality. It can be said that the printing pressure P needs to be sufficiently controlled. In the present situation where the printing pressure P is not sufficiently controlled, in practice, the rigidity of the printing drum 101 is designed and determined so that the necessary printing pressure P and ink discharge pressure F can be obtained. .

In the first embodiment, the temperature of the thermal head 91 is detected by the thermistor 91D as head temperature detecting means. The energy for perforation may be adjusted according to the detected ink viscosity.
Further, the energy for perforation may be adjusted according to the temperature of the thermal head, the viscosity of the ink, the type of the ink, and / or the printing speed.

(Modification 1) A modification 1 of the first embodiment will be briefly described with reference to FIG. 1, FIG. 17 and FIG. The first modification differs from the first embodiment only in that a viscosity detecting unit 21A is provided instead of the viscosity detecting unit 21. The viscosity detecting means 21A includes the viscosity detecting means 2
1, as shown in FIGS. 1, 17 and 18,
The current value detecting means 25 for detecting the current value supplied from the driving power supply 19 to the ink viscosity detecting motor 17 is eliminated, and the voltage value detecting means 2 for detecting the voltage of the driving power supply 19
The only difference is that the configuration is provided with 7A. FIG.
In FIG. 7, a symbol r indicates an internal resistance of the driving power supply 19.

Therefore, the viscosity detecting means 21A in the first modification detects the ink viscosity by detecting a change in the voltage value V applied to the ink viscosity detecting motor 17 by the driving power supply 19. Since the configuration is substantially the same as that of the first embodiment and is obvious, a detailed description thereof will be omitted to avoid redundant description.

(Embodiment 2) Embodiment 2 of the present invention will be described with reference to FIG. 1, FIG. 7, FIG. 15, FIG. 20, FIG. 21 and FIG. The second embodiment is different from the first embodiment only in that a viscosity detecting means 21B is provided instead of the viscosity detecting means 21. Viscosity detection means 2
1B is a block diagram showing the rotational speed indicated by a dotted line in FIG. The detection sensor 170 (hereinafter, referred to as
The only difference is that a pulse detection sensor 171 and a constant current drive power supply 19A are added.

That is, the viscosity detecting means 21B includes an ink viscosity detecting roller 16 which comes into contact with the ink application surface of the ink roller 120 below the doctor roller 121 of the ink supply means 119 via an ink layer, and the ink viscosity detecting roller 16 An ink viscosity detecting motor 17 as a roller driving means rotating at a constant torque, and a constant current driving power supply 19A as a constant power supply for supplying a constant current for causing the ink viscosity detecting motor 17 to rotate at a constant torque. And an encoder 170 as a roller speed detecting means for detecting the rotation speed of the ink viscosity detecting roller 16 and a pulse detection sensor 171.

The viscosity detecting means 21 according to the second embodiment
B is characterized in that the viscosity of the ink is detected by detecting a change in the rotation speed of the ink viscosity detecting roller 16.

The encoder 170 is an optical rotary encoder having a slit disk fixed to the output shaft 17a which is coaxial with the ink viscosity detecting roller 16. The pulse detection sensor 171 is a photo-interrupter-type optical sensor for generating a pulse in cooperation with the encoder 170 and holding the slit disk of the encoder 170 at a predetermined interval, and has a function as a pulse generator. Having. Then, the CPU 131 detects the viscosity of the ink based on a change in the pulse generated from the pulse detection sensor 171, that is, a pulse number signal having higher accuracy than the ink viscosity detection signal in the first embodiment.

Next, the operation will be briefly described focusing on the differences from the first embodiment. Since a constant current is always supplied from the constant current drive power supply 19A to the ink viscosity detection motor 17, the ink viscosity detection motor 17 is rotated with a constant torque (rotational force). The rotation speed of the ink viscosity detection motor 17 changes depending on the load due to the difference in ink viscosity.
This change in rotation speed is captured by a change in the number of pulses generated by cooperation between the encoder 170 and the pulse detection sensor 171. In other words, when the rotation speed of the ink viscosity detecting motor 17 changes due to the load due to the difference in the ink viscosity, the encoder 170 and the pulse detection sensor 171 are changed.
Since the pulse width (frequency) generated in cooperation with the above changes, a change in the viscosity of the ink can be detected, and the change is output to the CPU 131 as a pulse number signal.

In this case, the correlation data between the ink viscosity and the number of pulses is shown in FIG. 20 instead of the ink viscosity detection motor output voltage V [V] plotted on the horizontal axis in the correlation data shown in FIG. As shown, the ink viscosity detection motor output pulse value P _M [p indicating the number of pulses (frequency)
[ps] may be made to correspond with the horizontal axis. The energy adjustment pattern table for perforation and the printing pressure control pattern table according to the second embodiment for each ink type obtained in this manner are created.
It is stored in the OM 132 in advance. Drilling energy adjustment pattern table of the second embodiment, current pulses the number of pulses as shown in FIG. 21 ink viscosity detecting the motor output pulse indicating the (frequency) value P _M [pps] is that the horizontal axis, corresponding thereto The width will be taken on the vertical axis.

That is, the ROM 132 in the energy adjusting means 130 has been obtained in advance by an experiment or the like.
A drilling energy adjustment pattern table shown in FIG. 21 is stored in advance. The perforation energy adjustment pattern table is prepared for each corresponding ink type, and the perforation energy adjustment pattern table shown in FIG. 21 is one of the inks. In the second embodiment, This shows the one related to the black ink Ck. The drilling energy adjustment pattern table, ink viscosity detection motor output pulse value P _M [pps] is the horizontal axis, energizing pulse width have been taken on the vertical axis corresponding thereto, three stages to correspond to these The set print speed is assigned such that the first speed, the third speed, and the fifth speed step down in a stepwise manner. That is, the drilling energy adjustment pattern table, as the viscosity detection value at which the ink viscosity detecting the motor output pulse value P _M [pps] and setting the printing speed of the black ink Ck parameters, print speed in other words the ink viscosity detection signal This indicates that a predetermined energizing pulse width is set according to the setting signal. It should be noted that the above-described three-step setting printing speed is merely an example of a typical setting example, and the setting printing speed: second speed and fourth speed are omitted for convenience of explanation.

On the other hand, the printing pressure control pattern table according to the second embodiment has a pulse number (frequency) as shown in FIG.
Ink a viscosity detection motor output pulse value P _M [pp
s] is plotted on the horizontal axis, and the set printing pressure [N] most suitable for the machine conditions at that time and the number of printing pressure setting pulses corresponding to this are plotted on the vertical axis.

That is, the ROM 132 in the pressing force variable control means 130A previously stores the printing pressure control pattern table shown in FIG. As the printing pressure control pattern table,
A printing pressure control pattern table shown in FIG. 22 is prepared for each type of the corresponding ink, and shows one of the inks, that is, the black ink Ck in the second embodiment. The indicia pressure control pattern table, the ink viscosity detecting the motor output pulse value P _M [pps] is the abscissa, is the most appropriate setting printing pressure [N] and the printing pressure set number of pulses corresponding to the machine conditions at that time Each of them is plotted on the vertical axis, and three stages of the set printing speed:
The speed, the third speed, and the fifth speed are assigned so as to step down in steps. In other words, the sign pressure control pattern table, the ink viscosity detecting the motor output pulse value P _M [pps] and set printing speed is detected values of the viscosity of black ink Ck as a parameter, the printing speed setting in other words the ink viscosity detection signal This indicates that a predetermined pressing force, that is, the number of printing pressure setting pulses corresponding to the setting printing pressure [N] most suitable for the machine condition at that time is determined in accordance with the signal. In addition, the three-step set printing speed described above is
This is merely an example of a typical setting example, and the setting print speed: 2nd speed and 4th speed are omitted for convenience of explanation.

Therefore, according to the ink viscosity detecting method of the second embodiment, compared to the case of detecting an analog signal such as the current value I or the voltage value V as in the first embodiment or the first modification. Thus, there is an advantage that there is no generation of electric noise, the detection time is short, and the accuracy is high, and it is possible to perform energy setting for punching and printing pressure control with finer grain. Further, during the printing process, the printing pressure control can be appropriately performed while always detecting the viscosity of the ink. Note that the constant power supply may be a constant voltage supply that supplies a constant voltage. (Embodiment 3) FIGS. 3 and 7 show Embodiment 3 of the present invention. The third embodiment differs from the first embodiment in that the drum unit detection sensor 35 is removed, and an ink type setting key 41 serving as an ink type setting unit for setting the type of ink in the printing drum is used instead. Is mainly different. The ink type setting key 41 is used by a user or the like to know the type of ink in the print drum in advance and set the type of ink. Less than,
Only differences from the first embodiment will be described.

In the third embodiment, the energy adjusting means 130 controls the ink viscosity detected by the viscosity detecting means 21, the ink type set by the ink type setting key 41, and the printing speed set by the printing speed setting key 47. It has a function of selecting a predetermined energizing pulse width from a preset energy adjustment pattern table for drilling according to the speed and controlling the predetermined energizing pulse width to be applied to the heating element of the thermal head 91. .

In the third embodiment, the pressing force variable control means 130A is set by the ink viscosity detected by the viscosity detecting means 21, the ink type set by the ink type setting key 41, and the printing speed setting key 47. A predetermined pressing force is selected from a printing pressure control pattern table set in advance in accordance with the printing speed, and the pressing force varying means 2 is applied so that the predetermined pressing force is applied to the printing drum 101.
It has a function to control 0.

In the third embodiment, the type of ink in the printing drum is identified and detected to adjust the energy for perforation.
The process of performing the printing pressure control is the same as that of the first embodiment except for the following initial operation contents, and thus the description thereof is omitted. That is, when the user inputs the ink type of the drum unit known in advance and desired with the ink type setting key 41, the ink type setting signal is input to the CPU 131, and the LED lamp corresponding to the ink type is turned on.

(Embodiment 4) Embodiment 4 will be described with reference to FIGS. Embodiment 1 described above
In the third to third embodiments, the perforation energy setting and the printing pressure setting are performed in consideration of the parameters of the printing speed set by the printing speed setting key 47. The difference is that the parameters of the above are not considered. It is necessary to consider the printing speed when changing the printing speed in so-called “printing”, “test printing”, or normal printing, but since the setting of the printing speed can be changed arbitrarily even after plate making, this point In the following, a fourth embodiment, which is closer to how the actual machine is used, will be described. Hereinafter, points different from the first embodiment will be mainly described.

In the fourth embodiment, the energy adjustment means 130 is a predetermined energy adjustment for perforation according to the ink viscosity detected by the viscosity detection means 21 and the ink type detected by the drum unit detection sensor 35. It has a function of selecting a predetermined drilling energy from the pattern table and setting such that the predetermined drilling energy is applied to the heating element of the thermal head 91. The adjustment of the drilling energy is performed by changing the width of the energizing pulse to the heating element of the thermal head 91 as in the first embodiment.

In the ROM 132 in the energy adjusting means 130 according to the fourth embodiment, a drilling energy adjustment pattern table shown in FIG. 26, which is obtained in advance by experiments or the like, is stored in advance. The perforation energy adjustment pattern table is prepared for each type of the corresponding ink, and the perforation energy adjustment pattern table shown in FIG. 26 is one of the inks.
In the first embodiment, the one related to the black ink Ck is shown.
In this energy adjustment pattern table for perforation, a predetermined energizing pulse width is set in accordance with an ink viscosity detection motor output voltage value [V], which is a detected value of the viscosity of the black ink Ck, as a parameter. It means that it is done. The ROM 132 has a program (see flowcharts in FIGS. 24 and 25) relating to operations such as starting, stopping, and timing of each unit.
In addition, a program related to the operation of the energy adjusting unit 130 for executing the above function or necessary data is stored in advance.

The variable pressing force control means 130A has the same control function as in the first embodiment. Therefore, the ROM in the pressing force variable control means 130A in the fourth embodiment
132 stores the printing pressure control pattern table shown in FIG. Also, RO
In M132, a program (see the flowcharts of FIGS. 24 and 25) relating to the operation of executing the above function of the pressing force variable control unit 130A similar to that of the first embodiment is stored in advance.

In short, in the fourth embodiment, after the energy for perforation is set by the energy adjusting means 130, the pressing force variable control means 130A fetches the ink viscosity detection signal and the printing speed setting signal set by the printing speed setting key 47. Is used to set the printing pressure.

(Operation of the Fourth Embodiment) Next, the operation of the fourth embodiment will be described with reference to the flowcharts of FIGS. 24 and 25, focusing on differences from the operation of the first embodiment. FIG.
In the flowchart shown in FIG. The operation from to the input of the ink type detection signal for detecting the ink type of the drum unit 140 is performed in the same manner as the operation of the first embodiment shown in FIG. 8 (see steps S30 and S31).
Next, in step S32, the print drum 101 is idlingly rotated in the direction of arrow A in the drawing, similarly to the operation of the first embodiment. Next, the process proceeds to step S33, and an ink viscosity detection signal is input / taken into the CPU 131 of the energy adjusting unit 130 via the input port in the same manner as in the operation of the first embodiment. When the ink viscosity detection signal is input to the CPU 131, the process proceeds to step S34.
The CPU 131 calls the ink type detection signal from the RAM 133 and checks it against the perforation energy adjustment pattern table for each color stored in the ROM 132 beforehand. First, the ink Ck shown in FIG. Is selected. Then, the CPU 131 compares the ink viscosity detection signal (the output voltage value of the ink viscosity detection motor in the fourth embodiment) with the perforation energy adjustment pattern table for the ink Ck shown in FIG. Then, a predetermined drilling energy (energization pulse width) is set (step S35).

An example of setting the predetermined energizing pulse width is as follows. In other words, for example, when the ink viscosity detection signal ink viscosity detecting the motor output voltage value V is less than V ₂ or V ₃ is, PW _{± 0} is set as the energizing pulse width. As other examples, when the ink viscosity detection signal ink viscosity detecting the motor output voltage value V is less than V ₃ or V ₄ may, PW ₊₁ is set as the energizing pulse width.

Then, the process proceeds to a step S36, at which the above-described plate discharge process is executed and the printing drum 101 in parallel therewith.
Of the master making master 61c, that is, a plate feeding / discharging operation is performed.

Next, after the operator sets the number of prints with the numeric keypad 42 and presses the speed up key 47B of the print speed setting key 47 to select the set print speed: 5th, the print number setting signal and the print speed setting are set. The signal: 5th speed is sequentially taken into the CPU 131 of the pressing force variable control means 130A via the input port, and is temporarily stored in the RAM 133 in the same manner as in the case of the ink type detection signal, and is set as a condition for printing pressure control. You. And CPU1
The numerical display of the number of prints is LED
The information is displayed on the display unit 43, and the LED lamp of the speed indicator 48 corresponding to the set print speed: the fifth speed is turned on (see steps S37 and S38).

Then, the flow advances to a step S39, where a printing pressure control pattern table collation similar to the operation of the first embodiment is executed. That is, the CPU 131 calls up the ink type detection signal from the RAM 133 and
Is compared with the printing pressure control pattern table for each color stored in advance, and the printing pressure control pattern table for the ink Ck shown in FIG. 13 is selected first. Then, the CPU 131 determines the ink viscosity detection signal (the ink viscosity detection motor output voltage value in the fourth embodiment) and the print speed setting signal (set print speed: 5 speed) called from the RAM 133 and FIG. A comparison is made with the printing pressure control pattern table for the indicated ink Ck, and a predetermined printing pressure set pulse number corresponding to the set printing pressure (set pressing force) most suitable for the machine conditions at that time is determined.

An example of determining the predetermined number of printing pressure setting pulses is as follows. That is, for example, the output voltage value V of the ink viscosity detection motor is V ₂ as the ink viscosity detection signal.
The time of less than V _3, the printing speed setting signal = set printing speed is represented by a black thick line: in response to 5-speed, optimum settings printing pressure to mechanical conditions in the [N] is P ₊₁ [ N] is selected, and PL ₊₁ is determined as the printing pressure setting pulse number corresponding to the set printing pressure P ₊₁ [N]. As other examples, when the ink viscosity detection signal ink viscosity detecting the motor output voltage value V is V ₃ or greater, most suitable set printing pressure to mechanical conditions in the [N] is P ₊₃ [N] And the number of printing pressure setting pulses corresponding to the set printing pressure P ₊₃ [N] is P
L _{+ 3} is determined.

Then, the process proceeds to a step S40, where a printing pressure setting processing operation of a subroutine program shown in FIG. 10 similar to the first embodiment is executed. Next, the process proceeds to step S41, where it is determined whether or not the printing pressure setting processing operation is OK as in the first embodiment, and a series of operations similar to the first embodiment is performed (step S42).
-Step S44).

(Modification 2) Modification 2 of Embodiment 4 will be briefly described with reference to FIGS. 7, 24 and 25. This modified example 2 is different from the fourth embodiment in that a series of printing pressure control structures by the pressing force variable control means 130A is removed, and accordingly, steps S39 to S41 in the flowchart shown in FIG. The main difference is that control operations relating to pressure variation (printing pressure control pattern table collation, printing pressure setting, printing pressure setting okay?) Have been eliminated. Therefore, in the second modification, only the energy for drilling is set by the energy adjusting unit 130 similar to that of the fourth embodiment, and the control configuration and operation can be easily analogized from the fourth embodiment. A detailed description thereof will be omitted for avoidance.

The motor 17 for detecting the ink viscosity is cost-effective.
A DC motor is desirable in order to reduce noise and reduce the size in terms of size and weight. However, the present invention is not limited to this. Viscosity detection becomes possible.

The ink viscosity detecting roller 16 is used in FIG.
And the like, that is, the ink roller 120 and the doctor roller 121 are disposed so as to come into contact with the ink application surface on the downstream side in the rotation direction of the ink roller 120 via the ink layer in the vicinity of the doctor roller 121. Has the following advantages: That is, since the ink viscosity detecting roller detects the load due to the difference in the viscosity of the ink by the rotation of the roller, it is desirable that the measurement object (ink layer) is always under constant conditions. Therefore, if the ink viscosity detecting roller is installed at the position shown in FIG. 1 or FIG. 15 or the like, an ink layer having a constant film thickness can be measured by the doctor roller 121, so that there is an advantage that the detection accuracy is further improved.

The location of the ink viscosity detecting roller is shown in FIG.
The ink roller 120 and the doctor roller 121 within the range of the ink roller 120 corresponding to the non-printing portion at the edge of the printing drum 101 are not limited to the ink viscosity detecting roller 16 shown by the solid line and the broken line in FIG. In a device in which ink is sufficiently secured in the ink layer on the ink application surface on the downstream side in the rotation direction of the ink roller 120 in the vicinity of the ink roller 120, for example, a virtual line shown in FIG. The ink viscosity detecting roller 16 </ b> X may be provided at a location as described above. The ink viscosity detecting roller 16 </ b> X with the reference numeral in parentheses is shorter and more compact than the ink viscosity detecting roller 16. The ink viscosity detecting roller 16 </ b> X is an ink roller 1 corresponding to a non-printing portion at the edge of the printing drum 101.
It is arranged so as to come into contact with the ink application surface on the downstream side in the rotation direction of the ink roller 120 in the vicinity of the doctor roller 121 via the ink layer. One end of the ink viscosity detecting roller 16X is connected to an end of an output shaft 17a of an ink viscosity detecting motor 17 via a shaft (not shown), and the output shaft 17a is mounted on the left side of the ink roller side plate by a bearing (not shown). ) Is rotatably supported.

Embodiments of the present invention are described in Embodiments 1 to 4 above.
And viscosity detecting means 21, 21A, 2 of Modifications 1, 2 etc.
1B, the following configuration may be used as long as the ink viscosity detecting roller is not installed at the site shown in FIGS. Good. That is, each of the viscosity detecting means 21, 21A, 21B according to the first to fourth embodiments and the first and second modifications.
In addition to removing the ink viscosity detecting rollers 16 and 16X from the configuration described above, the doctor roller 121 of the ink supply means 119 is provided with the function of the ink viscosity detecting roller 16, as shown in FIG. In this case, the doctor roller 121 of the ink supply means 119 may also serve as the ink viscosity detecting roller 16. As a result, the number of parts of the apparatus can be reduced, the apparatus can be simplified, and the cost can be reduced.

The viscosity detecting means of the present invention is different from the viscosity detecting means 2 in each of Embodiments 1 to 4 and each of the above modifications.
Ink viscosity detecting rollers 16 and 16 of 1, 21A and 21B
X or the doctor roller 121 is not limited to the one that also serves as the ink viscosity detecting roller 16. The current value to the ink pump driving motor that detects the load fluctuation of the ink pump or drives the ink pump. Or a change in voltage value may be detected.

An embodiment of the present invention is the same as that of the first embodiment.
The present invention is not limited to the pressing force varying means 20 of the first to fourth and modified examples 1 and 2, and the printing pressure may be controlled by the pressing force varying means 20A using an impression cylinder as shown in FIG. In the figure, reference numeral 125 denotes an impression cylinder as a pressing means. The impression cylinder 125 has a cutout recess 125a similar to that disclosed in, for example, Japanese Patent Application Laid-Open No. Hei 5-201115. In the present embodiment, the main difference is that the pressing force varying means 20A has an impression cylinder displacement means 22A for selectively bringing the impression cylinder 125 into and out of contact with the outer peripheral surface of the printing drum 101, instead of the press roller displacement means 22. .

The impression cylinder displacement means 22A includes an impression cylinder support shaft 126 for rotatably supporting the impression cylinder 125, and an impression cylinder support shaft 126.
And a pair of swingable left and right arms 127a, 127b, which are disposed between the fulcrum shaft 128 provided on the rear side of the impression cylinder 125 and extend forward in the sheet conveyance direction X; A pair of left and right cam followers 127c disposed on the left and right arms 127a and 127b between the free ends of the pair of left and right arms 127a and 127b to which one end of the spring 6 is locked and the impression cylinder support shaft 126; It mainly comprises a pair of left and right printing pressure cams 129 which are rotatably disposed near the pair of left and right cam followers 127c and which have contoured peripheral surfaces selectively engaged with the pair of left and right cam followers 127c.
The pair of left and right printing pressure cams 129 are provided by the press roller driving unit 1.
A known configuration is adopted in which the printing drum 101 is rotated in synchronization with the rotation of the printing drum 101 by means similar to 50.

It should be noted that the impression cylinder displacing means is
It is needless to say that the invention is not limited to A and may be one using an eccentric shaft as disclosed in the above-mentioned JP-A-5-201115.

The embodiment of the present invention is not limited to the above-described pressing force varying means 20, 20A, but includes a printing pressure control motor 14, an encoder 12, and a pulse detection sensor 13 which constitute these pressing force varying means 20, 20A. Alternatively, by providing a stepping motor, it is of course possible to perform the same printing pressure control as described above by a well-known rotation amount control method using this stepping motor alone. Also,
The means for varying the printing pressure itself in the pressing force varying means 20 and 20A is not limited to the one described above, and may be, for example, a construction using an electric actuator or a solenoid as disclosed in JP-A-6-340162. Good.

The ink type detecting means includes, for example, dip switches 133 and 135 described in FIGS. 3 and 4 of JP-A-6-199028, a code reading detecting device such as a bar code, and a printing drum. A color detection sensor for directly detecting the color itself of the ink supplied to the printing drum, or the like, by identifying the color identification shape portion provided by the photoelectric sensor, or by providing a color detection sensor or the like to directly determine the type of ink in the printing drum to be used. What is detected may be used.

The ink supply means of the present invention is not limited to the ink supply means 119 described above.
It is needless to say that the present invention can also be applied to a printing apparatus configured to supply ink from the outside of a printing drum as disclosed in JP-A-17013 (Claims 1 to 6 for solving the problem). See the described invention).

The embodiments of the present invention are not limited to the above-described first to fourth embodiments and the first and second modifications, and if the accuracy of detecting the viscosity of the ink is not so required,
Instead of the ink viscosity detecting roller 16, an ink pool 122
May be a very small rotating roller immersed in the ink of the ink reservoir 122, or an ink viscosity detecting member composed of a very small screw immersed in the ink of the ink reservoir 122.

The embodiments of the present invention are not limited to the above-described first to fourth embodiments and the first and second modified examples. For example, when the present invention is not used in a low-temperature environment and image density unevenness does not occur. In the case where the rigidity in the axial direction of the print drum 101 is optimized and the image density unevenness does not occur even in a low-temperature environment, the pressing force varying means and the pressing force A configuration in which the variable pressure control means is omitted may be adopted.

Further, the embodiment of the present invention is not limited to the above-described first to fourth embodiments and the first and second modifications, but includes a combination of information parameters for performing energy adjustment for perforation, that is, ink viscosity. And a combination of parameters of the ink type and the printing speed detected by the ink type detecting means or set by the ink type setting means (claims 1 to 3 in the means for solving the problem). 6).

[0162]

As described above, according to the first aspect of the present invention, the viscosity itself which directly affects the printed image is detected and measured by the viscosity detecting means for detecting the viscosity of the ink. Since the energy adjusting means adjusts the energy for perforation according to the ink viscosity detected by the viscosity detecting means, it is possible to set an appropriate energy for perforation with respect to environmental fluctuations, and to always print with stable quality. Images can be obtained.

According to the second aspect of the present invention, the viscosity detecting means for detecting the viscosity of the ink detects and measures the viscosity of the ink which directly affects the printed image, and the energy adjusting means detects the viscosity of the ink. The perforation energy is adjusted according to the ink viscosity detected by the means and the ink type detected by the ink type detection means. Energy can be set, and a print image of stable quality can be always obtained.

According to the third aspect of the present invention, the viscosity detecting means for detecting the viscosity of the ink detects and measures the viscosity of the ink which directly affects the printed image, and the energy adjusting means detects the viscosity of the ink. The perforation energy is adjusted according to the ink viscosity detected by the means and the ink type set by the ink type setting means, so that proper perforation can be performed even when the viscosity of ink changes due to environmental fluctuations and ink type differences. Energy can be set, and a print image of stable quality can be always obtained.

According to the fourth aspect of the present invention, the viscosity detecting means for detecting the viscosity of the ink detects and measures the viscosity of the ink which directly affects the printed image, and the energy adjusting means detects the viscosity of the ink. The energy for perforation is adjusted according to the ink viscosity detected by the means and the printing speed set by the printing speed setting means, so that it is appropriate for changes in ink viscosity and changes in the set printing speed due to environmental fluctuations. The energy for perforation can be set, and a print image of stable quality can be always obtained.

According to the fifth aspect of the present invention, the viscosity detecting means for detecting the viscosity of the ink detects and measures the viscosity itself of the ink which directly affects the printed image, and the energy adjusting means detects the viscosity. The energy for perforation is adjusted according to the ink viscosity detected by the means, the ink type detected by the ink type detection means, and the printing speed set by the printing speed setting means. Therefore, it is possible to set an appropriate perforation energy with respect to a change in the viscosity detection and a change in the set printing speed, and it is possible to always obtain a stable quality print image.

According to the sixth aspect of the present invention, the viscosity itself which directly affects the printed image is detected and measured by the viscosity detecting means for detecting the viscosity of the ink. The perforation energy is adjusted according to the ink viscosity detected by the means, the ink type set by the ink type setting means, and the printing speed set by the printing speed setting means. Therefore, it is possible to set an appropriate perforation energy with respect to a change in the viscosity detection and a change in the set printing speed, and it is possible to always obtain a stable quality print image.

According to the seventh aspect of the present invention, in addition to the above-described components, the energy adjusting means adjusts the drilling energy in consideration of the thermal head temperature detected by the head temperature detecting means. Even when the head operates continuously for a long time and the temperature rises, it is possible to set appropriate energy for perforation, and it is possible to obtain a print image of more stable quality.

According to the eighth aspect of the present invention, in addition to each of the above-described structures, the pressing force variable control means controls the printing pressure control pattern table preset according to the ink viscosity detected by the viscosity detecting means. Since a predetermined pressing force is selected from among them, and the pressing force variable means is controlled so that the selected predetermined pressing force is applied to the printing drum, especially when the ink viscosity increases in a low temperature environment, the printing paper It is possible to prevent the occurrence of print density unevenness due to lower image density in the both end regions than in the central region. In addition, it is possible to set and control an appropriate printing pressure even with respect to a change in ink viscosity due to environmental fluctuations, and it is possible to always obtain a stable quality print image.

According to the ninth aspect of the present invention, in addition to the above-described components, ink supply means for supplying ink to the inner peripheral surface of the printing drum is provided, and the viscosity detecting means is provided with:
An ink viscosity detection roller that comes into contact with the ink application surface of the ink supply means via an ink layer; a roller driving means that rotates the ink viscosity detection roller at a constant rotation speed; and a power supply that supplies power to the roller driving means. A current value detecting means for detecting a current value supplied from the power supply to the roller driving means, and detecting a change in the current value to detect the viscosity of the ink. In addition, even when the ink viscosity in the printing drum is different from the ink viscosity in the ink container (it tends to occur after the apparatus is left for a long time), the ink viscosity can be detected more appropriately. In addition,
The viscosity of the ink can be easily detected and measured by detecting a change in the current value by the current value detecting means without directly measuring the viscosity.

According to the tenth aspect of the present invention, in addition to the above components, an ink supply means for supplying ink to the inner peripheral surface of the printing drum is provided, and the viscosity detecting means comprises an ink supply means. An ink viscosity detection roller that contacts the ink application surface of the means via an ink layer, and a roller driving unit that rotates the ink viscosity detection roller at a constant rotation speed;
A power supply for supplying power to the roller driving means; and a voltage value detecting means for detecting a voltage value applied to the roller driving means by the power supply, and detecting a change in the voltage value to detect a viscosity of the ink. Therefore, the viscosity of the ink immediately before printing can be detected, and even when the ink viscosity in the printing drum is different from the ink viscosity in the ink container or the like (which is likely to occur after the apparatus has been left for a long time), the ink Viscosity can be detected. In addition, the viscosity of the ink can be easily detected and measured by detecting a change in the voltage value by the voltage value detecting means without directly measuring the viscosity.

According to the eleventh aspect of the present invention, in addition to the above-described components, an ink supply unit for supplying the ink is provided on the inner peripheral surface of the printing drum. An ink viscosity detection roller that comes into contact with the ink application surface of the supply means via an ink layer, and a roller driving unit that rotates the ink viscosity detection roller with a constant torque;
A constant power supply for supplying a constant power for driving the roller driving means to rotate at a constant torque, and a roller speed detection means for detecting a rotation speed of the ink viscosity detection roller,
Since the ink viscosity is detected by detecting the change in the rotation speed of the ink viscosity detection roller, it is possible to detect the viscosity of the ink immediately before printing. (When it is likely to occur after the apparatus has been left for a long time), the viscosity of the ink can be detected more appropriately. In addition, since the ink viscosity is detected by detecting the change in the rotation speed of the ink viscosity detection roller without directly measuring the ink viscosity, finer changes in the ink viscosity can be detected. Even so, the detection can be performed with higher accuracy. Furthermore, the degree to which the detection accuracy of the ink viscosity is affected by the electrical noise can be reduced.

According to the twelfth aspect of the present invention, in addition to the above configuration, the roller speed detecting means cooperates with the encoder disposed on the ink viscosity detecting roller and the encoder disposed close to the encoder. And a pulse generator that generates a pulse. The ink viscosity is detected based on a change in the pulse generated from the pulse generator. It is no longer affected by noise.

According to the thirteenth aspect of the present invention, in addition to the above-mentioned components, the ink supply means includes an ink roller for supplying ink to the inner peripheral surface of the printing drum, and a doctor disposed in close proximity to the ink roller. Roller, and the ink viscosity detecting roller is disposed so as to come into contact with the ink application surface of the ink roller via the ink layer. Since the detection can be performed, in addition to the above-described respective effects, it is possible to set more appropriate drilling energy with respect to environmental fluctuations, and it is possible to always obtain a stable quality print image.

According to the fourteenth aspect of the present invention, in addition to the above constitutions, an ink viscosity detecting roller is provided on the ink application surface on the downstream side in the rotation direction of the ink roller in the vicinity of the ink roller and the doctor roller. In addition to the above effects, the doctor roller can detect and measure the viscosity of the ink in the ink layer having a constant film thickness, so that the detection accuracy is higher and the ink roller is provided. And the doctor roller do not affect the supply of ink measured and applied to the ink roller.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of a stencil printing machine according to a first embodiment of the present invention.

FIG. 2 is a perspective view around a press roller driving unit in the first embodiment.

FIG. 3 is a plan view of an operation panel according to the first embodiment.

FIG. 4 is a schematic sectional view of a drum unit detection sensor according to the first embodiment.

FIG. 5 is a block diagram illustrating a part of a viscosity detecting unit according to the first embodiment.

FIG. 6 is a block diagram illustrating constant rotation speed control of an ink viscosity detection motor according to the first embodiment.

FIG. 7 is a block diagram illustrating a control configuration of each embodiment.

FIG. 8 is a flowchart for explaining a schematic operation of the first embodiment.

FIG. 9 is a flowchart of a part following FIG. 8;

FIG. 10 is a flowchart for explaining the printing pressure setting in FIG. 8;

FIG. 11 is a graph showing a correlation between ink viscosity and an output voltage of an ink viscosity detection motor in the first embodiment.

FIG. 12 is a graph showing a drilling energy adjustment pattern table according to the first embodiment.

FIG. 13 is a graph showing a printing pressure control pattern table for setting printing pressure in the first embodiment.

FIG. 14 is a partial cross-sectional view illustrating a printing state of a printing pressure unit according to the first embodiment.

FIG. 15 is an enlarged perspective view showing a part of a viscosity detecting unit according to Embodiment 2 of the present invention.

FIG. 16 is a schematic front view showing another example of the pressing means.

FIG. 17 is a block diagram illustrating a part of a viscosity detecting unit according to a first modification of the first embodiment.

FIG. 18 is a block diagram illustrating constant rotation speed control of an ink viscosity detection motor according to a first modification of the first embodiment.

FIG. 19 is a configuration diagram illustrating an overall configuration of a stencil printing apparatus to which the present invention is applied.

FIG. 20 is a graph showing a correlation between an ink viscosity and an output pulse value of an ink viscosity detection motor according to the second embodiment.

FIG. 21 is a graph showing a drilling energy adjustment pattern table according to the second embodiment.

FIG. 22 is a graph showing a printing pressure control pattern table for setting printing pressure in the second embodiment.

FIG. 23 is a diagram for explaining an operation around a heating element of the thermal head according to the present invention.

FIG. 24 is a flowchart illustrating a schematic operation according to the fourth embodiment.

FIG. 25 is a flowchart of the part following FIG. 24;

FIG. 26 is a graph showing a drilling energy adjustment pattern table according to the fourth embodiment.

[Explanation of symbols]

16, 16X Ink viscosity detecting roller constituting the viscosity detecting means 17 Ink viscosity detecting motor as the roller driving means constituting the viscosity detecting means 19 Drive power supply as the power supply constituting the viscosity detecting means 19A Constant power constituting the viscosity detecting means Constant current drive power supply as power supply 20, 20A Pressing force variable means 21, 21, A, 21B Viscosity detection means 25 Current value detection means 27A Voltage value detection means 35 Drum unit detection sensor as ink type detection means 41 Ink as ink type setting means Type setting key 47 Printing speed setting key 61c as printing speed setting means 61c Pre-printed master as prepressed master 62 Printing paper 91D Thermistor as head temperature detecting means 101 Printing drum 103 Press roller as pressing means 119 Ink supply means 120 Ink roller 121 which constitutes ink supply means 121 Doctor roller which constitutes ink supply means 125 Impression cylinder as pressing means 130 Energy adjustment means 130A Variable pressing force control means 131 CPU which constitutes energy adjustment means 132 ROM which constitutes energy adjustment means 133 RAM constituting energy adjustment means 170 Encoder constituting roller speed detection means 171 Pulse detection sensor as pulse generator constituting roller speed detection means

Claims (14)

[Claims] 1. A master making a master by causing a heating element of a thermal head to generate heat, winding the master made on the outer peripheral surface of a printing drum, supplying ink to the master on the printing drum, and pressing means. A printing apparatus that presses a printing paper against the printing drum to form a print image on the printing paper, wherein a viscosity detection unit that detects the viscosity of the ink, and a viscosity detection unit that responds to the ink viscosity detected by the viscosity detection unit And a energy adjusting means for adjusting perforation energy supplied to the heating element of the thermal head to a predetermined energy. 2. A master making a master by causing a heat generating element of a thermal head to generate heat, winding the master made on the outer peripheral surface of a printing drum, supplying ink to the master on the printing drum, and pressing means. In a printing apparatus for forming a print image on the printing paper by pressing a printing paper against the printing drum, a viscosity detecting means for detecting the viscosity of the ink, and an ink type detecting means for detecting the type of the ink Energy adjusting means for adjusting perforation energy supplied to the heating element of the thermal head to a predetermined energy according to the ink viscosity detected by the viscosity detecting means and the ink type detected by the ink type detecting means; A printing device comprising: 3. A master is made by making a heating element of a thermal head generate heat, and the master made is wound around an outer peripheral surface of a printing drum, ink is supplied to the master on the printing drum, and pressing means is provided. In a printing apparatus for forming a print image on the printing paper by pressing a printing paper against the printing drum, a viscosity detecting means for detecting the viscosity of the ink, and an ink type setting means for setting the type of the ink Energy adjusting means for adjusting perforation energy supplied to the heating element of the thermal head to a predetermined energy according to the ink viscosity detected by the viscosity detecting means and the ink type set by the ink type setting means. A printing device comprising: 4. A master making a master by causing a heating element of a thermal head to generate heat, winding the master made on the outer peripheral surface of a printing drum, supplying ink to the master on the printing drum, and pressing means. A printing device that presses printing paper against the printing drum to form a print image on the printing paper, comprising a viscosity detecting unit that detects the viscosity of the ink, and a printing speed of the printing device is variable. A printing speed setting means for selectively setting the printing speed, and according to the ink viscosity detected by the viscosity detecting means and the printing speed set by the printing speed setting means,
A printing apparatus, comprising: an energy adjusting unit that adjusts perforation energy supplied to the heating element of the thermal head to a predetermined energy. 5. A master making a master by causing a heating element of a thermal head to generate heat, winding the master made on the outer peripheral surface of a printing drum, supplying ink to the master on the printing drum, and pressing means. In a printing apparatus for forming a print image on the printing paper by pressing a printing paper against the printing drum, a viscosity detecting means for detecting the viscosity of the ink, and an ink type detecting means for detecting the type of the ink A printing speed of the printing apparatus is variable, a printing speed setting means for selectively setting the printing speed, an ink viscosity detected by the viscosity detecting means and an ink viscosity detected by the ink type detecting means. According to the ink type and the printing speed set by the printing speed setting means,
A printing apparatus, comprising: an energy adjusting unit that adjusts perforation energy supplied to the heating element of the thermal head to a predetermined energy. 6. A master is made by making a heat generating element of a thermal head generate heat, the master made is wound around an outer peripheral surface of a printing drum, ink is supplied to the master on the printing drum, and pressing means is provided. In a printing apparatus for forming a print image on the printing paper by pressing a printing paper against the printing drum, a viscosity detecting means for detecting the viscosity of the ink, and an ink type setting means for setting the type of the ink A printing speed of the printing apparatus is variable, a printing speed setting means for selectively setting the printing speed, and an ink viscosity detected by the viscosity detecting means and an ink type setting means set by the ink type setting means. According to the ink type and the printing speed set by the printing speed setting means,
A printing apparatus, comprising: an energy adjusting unit that adjusts perforation energy supplied to the heating element of the thermal head to a predetermined energy. 7. The printing apparatus according to claim 1, further comprising head temperature detecting means for detecting a temperature of the thermal head, wherein said energy adjusting means detects the temperature by said head temperature detecting means. A printing apparatus wherein the energy for perforation is adjusted in consideration of the temperature of the thermal head. 8. The printing apparatus according to claim 1, wherein the pressing force is changed by a pressing force varying means for changing a pressing force of the pressing means against the printing drum, and the viscosity is detected by the viscosity detecting means. The predetermined pressing force is selected from a preset printing pressure control pattern table in accordance with the ink viscosity, and the pressing force varying means is applied so that the selected predetermined pressing force is applied to the printing drum. And a pressing force variable control means for controlling the pressure. 9. The printing apparatus according to claim 1, wherein an ink supply means for supplying the ink to an inner peripheral surface of the printing drum is provided in the printing drum. Wherein the viscosity detecting means is an ink viscosity detecting roller that comes into contact with the ink application surface of the ink supply means via an ink layer, and a roller driving means that rotates the ink viscosity detecting roller at a constant rotation speed. A power supply for supplying power to the roller driving means; and a current value detecting means for detecting a current value supplied from the power supply to the roller driving means. By detecting a change in the current value, A printing device for detecting viscosity. 10. The printing apparatus according to claim 1, wherein an ink supply means for supplying the ink to an inner peripheral surface of the printing drum is provided in the printing drum. Wherein the viscosity detecting means is an ink viscosity detecting roller that comes into contact with the ink application surface of the ink supply means via an ink layer, and a roller driving means that rotates the ink viscosity detecting roller at a constant rotation speed. A power supply for supplying electric power to the roller driving means; and a voltage value detecting means for detecting a voltage value applied to the roller driving means by the power supply. By detecting a change in the voltage value, the viscosity of the ink is determined. A printing apparatus for detecting a printing condition. 11. The printing apparatus according to claim 1, wherein an ink supply means for supplying the ink to an inner peripheral surface of the printing drum is provided in the printing drum. The viscosity detecting means includes: an ink viscosity detecting roller that contacts an ink application surface of the ink supply means via an ink layer; a roller driving means that rotates the ink viscosity detecting roller at a constant torque; A constant power supply for supplying a constant power for driving the roller to rotate at a constant torque by the roller driving unit; and a roller speed detecting unit for detecting a rotation speed of the ink viscosity detecting roller. A printing apparatus, wherein the viscosity of the ink is detected by detecting a change in rotation speed. 12. A printing apparatus according to claim 11, wherein said roller speed detecting means includes an encoder disposed on said ink viscosity detecting roller, and a pulse disposed in close proximity to said encoder and cooperating with said encoder. And a pulse generator that generates the pressure, and detects the viscosity of the ink based on a change in the pulse generated from the pulse generator. 13. A printing apparatus according to claim 9, wherein said ink supply means includes an ink roller for supplying said ink to an inner peripheral surface of said printing drum, and an ink roller provided adjacent to said ink roller. A printing apparatus, comprising: a doctor roller disposed so as to be in contact with the ink roller, wherein the ink viscosity detecting roller is disposed so as to contact the ink application surface of the ink roller via the ink layer. 14. A printing apparatus according to claim 13, wherein said ink viscosity detecting roller is provided on said ink coating surface on a downstream side in a rotation direction of said ink roller in a portion close to said ink roller and said doctor roller. A printing device, which is arranged to contact through a printer.