WO2007032477A1

WO2007032477A1 - Stencil printing method

Info

Publication number: WO2007032477A1
Application number: PCT/JP2006/318369
Authority: WO
Inventors: Hajime Tsunoda; Yoshihiro Hayashi; Teruaki Hashizume
Original assignee: Riso Kagaku Corporation
Priority date: 2005-09-16
Filing date: 2006-09-15
Publication date: 2007-03-22
Also published as: JP2007083396A

Abstract

A stencil printing method which uses a stencil printing device comprising a drum that is free to rotate and mounted on the surface of the outer peripheral wall thereof with mimeograph paper, an ink supplying means having an ink supply unit positioned on the printing-upstream side of the maximum printing area of the drum's outer peripheral wall to supply ink onto the surface of the outer peripheral wall from this ink supply unit, and a press roll pressing a fed printing medium against the outer peripheral wall, and which transfers onto the printing medium ink that has passed through the perforated portions in plate-made mimeograph paper by pressing with the press roll while rotating the drum mounted with the plate-made mimeograph paper, wherein printing is carried out so that the relation between a pressing pressure (A:N) by the press roll, the peripheral speed (B:m/s) of the drum, ink viscosity (C:mPa·s) and the thickness (D:μm) of the mimeograph paper satisfies the following expression (1). (Expression 1) 130≤√(B/A)×(C+200)×√D≤400 (1)

Description

Specification

Stencil printing method

Technical field

[0001] The present invention relates to stencil printing using a stencil printing apparatus that transfers a printing medium while pressing the printing medium to a drum on which a stencil sheet (master) is mounted, and transfers ink oozing from the perforations of the stencil sheet to the printing medium. Regarding the method.

Background art

[0002] The stencil printing method does not require complicated operations such as washing after use, and does not require a specialized operator, compared to printing methods such as offset printing, gravure printing, and relief printing. It has good quality and simplicity. Since the use of thermal heads as a device for thermal heads V, since the stencil printing method, image processing has been digitized so that high-quality printed materials can be easily obtained in a short time. As a result, the convenience of information processing terminals is increasingly recognized.

[0003] As a printing method of the conventional stencil printing apparatus, there are an inner press method (Patent Document 1) and an after press method (Patent Document 2).

In a conventional inner press type and outer press type stencil printing machine, an ink supply mechanism is provided inside the drum so that ink is supplied to the drum outer wall, and the ink is stored in a so-called ink reservoir. Always in a state of accumulation. Therefore, if printing is not performed for a long time, the ink accumulated in the ink reservoir or the ink adhering to the drum will be left in contact with the atmosphere for a long time inside the printing machine. However, there are problems that the ink changes in quality, and the printed image after being left is dull and uneven in density. Furthermore, since various rolls for supplying ink must be arranged inside the drum, there is a problem that it is difficult to make the drum small and light.

Therefore, the present applicant has developed a printing apparatus based on a new printing system that can solve such problems (Patent Documents 3 and 4). In these devices, ink is supplied to the surface of the drum outer peripheral wall at the upstream side of the drum outer peripheral wall in the printing mode. Ink reservoir Etc., the ink is not left in a neglected state. In other words, the ink supplied to the drum is held in a substantially sealed space between the outer peripheral wall of the drum and the stencil paper, and contact with the atmosphere is minimized. Therefore, the quality change of the ink is suppressed, and various types of ink can be used. Furthermore, since there is no need to provide an ink supply mechanism inside the drum, the drum can be made smaller and lighter.

(Patent Document 1) Japanese Patent Laid-Open No. 7-132675

(Patent Document 2) Japanese Patent Application Laid-Open No. 2001-246828

(Patent Document 3) JP 2004-122712 A

(Patent Document 4) Japanese Unexamined Patent Publication No. 2005-53209

[0005] In this new type of printing apparatus, a printing medium (printing paper) is supplied between a plate cylinder of a drum on which a stencil stencil sheet that has been subjected to platemaking is mounted and a press roll, and the printing medium is supplied by this press roll. In addition to being pressed against the outer peripheral wall of the drum, the ink supplied by the upstream force in the printing direction is diffused downstream while being squeezed between the outer peripheral wall and the stencil paper. ing. In other words, in stencil printing devices such as conventional lithographs (manufactured by Riso Kagaku Co., Ltd.), the press roll only performs ink transfer, whereas in this new printing device, the press roll is ink transfer. It plays two roles: the action and the diffusion action that spreads ink over the entire outer peripheral wall of the drum.

However, in some cases, the ink is not diffused smoothly and uniformly. As a result, an image defect occurs in an image where the ink supply is insufficient, or the ink supply is sufficient. However, it has been found that there is a peculiar problem that conventional devices do not have, such as the perforation force of stencil paper that causes ink to partially float and cause spotted stains on printed matter.

[0006] Accordingly, the present invention provides a stencil printing method in which a uniform image can be obtained over the entire printing surface without image defects or dot-like stains in printing using the above-described new stencil printing apparatus. With the goal.

Disclosure of the invention

[0007] The present invention includes a drum that is rotatable and has a stencil sheet mounted on the surface of its outer peripheral wall, and an ink supply unit at a position upstream of printing from the maximum printing rear of the outer peripheral wall of the drum. I A stencil printing machine (hereinafter referred to as “RK machine”) comprising ink supply means for supplying ink from the ink supply unit to the surface of the outer peripheral wall, and a press roll for pressing the fed printing medium against the outer peripheral wall. Stencil, which is transferred to the printing medium by passing the ink from the perforated part of the stencil sheet that has been made by rotating the drum on which the stencil sheet that has been made by the plate is pressed with a press roll while rotating. Printing method,

The relationship between the pressing force by the press roll (A: N), the peripheral speed of the drum (B: m / s), the viscosity of the ink (C: mPa · s), and the thickness of the stencil sheet (D: m) is The present invention relates to a stencil printing method that performs printing so as to satisfy (1).

(Number 1)

130≤ ^ (B / A) X (C + 200) X ^ D≤400 (1)

Brief Description of Drawings

FIG. 1 shows a first embodiment of a preferred stencil printing apparatus and is a schematic configuration diagram thereof.

FIG. 2 is a perspective view of a drum showing a first embodiment of a preferred stencil printing apparatus.

FIG. 3 shows a first embodiment of a preferred stencil printing apparatus, and is a cross-sectional view taken along line A1-A1 in FIG.

FIG. 4 shows a first embodiment of a preferred stencil printing apparatus, and is a cross-sectional view taken along line B 1 -B 1 in FIG.

FIG. 5 is a plan view of a drum showing an ink supply unit according to a first embodiment of a preferred stencil printing apparatus.

FIG. 6 shows a first embodiment of a preferred stencil printing apparatus, and is a cross-sectional view taken along line C1-C1 in FIG.

FIG. 7 is a partial cross-sectional view illustrating a first embodiment of a preferred stencil printing apparatus and illustrating an ink diffusion mechanism.

FIG. 8 is a plan view of a part of the drum, showing a modification of the ink supply unit of the first embodiment of the preferred stencil printing apparatus.

FIG. 9 is a sectional view taken along line C 4 -C 4 in FIG. 8, showing a modification of the ink supply unit of the first embodiment of the preferred stencil printing apparatus.

FIG. 10 is a perspective view of a drum showing a second embodiment of a preferred stencil printing apparatus. FIG. 11 is a cross-sectional view taken along the line A 2 -A 2 in FIG. 10, showing a second embodiment of a preferred stencil printing apparatus.

12 is a cross-sectional view taken along the line B2-B2 in FIG. 10, showing a second embodiment of a preferred stencil printing apparatus.

FIG. 13 is a schematic view showing the outer peripheral wall of a drum, showing a second embodiment of a preferred stencil printing apparatus.

FIG. 14 is a perspective view of a drum showing a third embodiment of a preferred stencil printing apparatus.

FIG. 15 is a cross-sectional view taken along the line A 3 -A 3 in FIG. 14, showing a third embodiment of a preferred stencil printing apparatus.

FIG. 16 is a cross-sectional view taken along line B3-B3 in FIG. 14, showing a third embodiment of a preferred stencil printing apparatus.

[FIG. 17] FIG. 17 shows a modified example of the ink leakage prevention groove, (a) is a sectional view near the ink leakage prevention groove, (b) is a partial plan view near the ink leakage prevention groove, and (c). Fig. 4 is a sectional view for explaining the behavior of a stencil sheet.

FIG. 18 shows a fourth embodiment of a preferred stencil printing apparatus, and is a schematic view in which the outer peripheral wall of the drum is developed.

FIG. 19 is a sectional view of a drum, showing a fifth embodiment of a preferred stencil printing apparatus.

FIG. 20 shows a fifth embodiment of a preferred stencil printing apparatus, and is an explanatory view showing a state in which the maximum printing area is divided into six divided areas.

FIG. 21 is a control block diagram showing a fifth embodiment of a preferred stencil printing apparatus.

FIG. 22 is a control block diagram showing a modified example of the fifth embodiment of a preferred stencil printing apparatus.

FIG. 23 is a front view of a drum and a press roll, showing a seventh embodiment of a preferred stencil printing apparatus.

[FIG. 24] FIG. 24 is a schematic configuration diagram schematically showing an apparatus used for measuring the bobbin length.

BEST MODE FOR CARRYING OUT THE INVENTION

In order to improve the ink diffusion, the inventors We examined the arrangement method of the supply section and the adjustment of the ink supply amount. However, this alone has been enough to improve sufficiently. Therefore, a study was conducted in consideration of the pressing force (printing pressure) applied by the press roll during printing, the peripheral speed of the drum, the viscosity of the ink used, and the thickness of the stencil paper.

Lithographic the conventional stencil printing device, such as (Riso Kagaku Co., Ltd.) is generally pressing force 50～300N, the peripheral speed of the drum is 0. 5~1. 25mZs (print speed 60～150Min ^_1), Ink viscosity is 1 million mPa's or more (ink viscosity at lOPa when shearing stress is increased from 0 Pa at a speed of 0.1 PaZs at 23 ° C), and the stencil sheet thickness is about 20-50 m Is set. As a result of applying this same condition to the RK system, the problem of image loss still remained even though the spot-like stain could be improved.

As will be described later, FIG. 1 is a schematic configuration diagram showing an embodiment of an RK apparatus, and FIG. 7 is a partial cross-sectional view illustrating an ink diffusion mechanism. As shown in FIG. 7, the ink 56 held between the outer peripheral wall 53 of the drum 26 and the stencil sheet 18 is diffused downstream in the printing direction while being squeezed by the pressing force of the press roll 35. The diffused ink 56 oozes out from the perforations of the stencil sheet 18 and is transferred to the printing paper 37 side. In this way, an image is printed on the printing paper 37 in the process of passing between the outer peripheral wall 53 of the drum 26 and the press roll 35. “Spot-like stains” means that after printing is finished (after passing through the press roll), the ink floats in the form of dots from the perforations of the stencil sheet 18, and this ink relief causes spot-like stains on the next printed image. It is a phenomenon that is formed.

[0011] As a cause of image chipping and spot-like smears, the present inventors have adhered to the stencil paper 18 after printing and the amount of ink impregnated and the ink remaining on the outer peripheral wall 53 of the drum 26. We determined that the amount was related, and considered controlling the total amount of this ink. Here, the total amount of ink impregnated on the stencil sheet after printing and the amount of ink remaining on the outer peripheral wall of the drum after printing is called “under-master ink amount”. . In the RK device, the power of the ink supply section The force that spreads the ink supplied under the stencil paper with a press roll and spreads over the entire printing surface. The amount of ink under the master is not uniform, and unevenness occurs in which the amount of ink under the master is partially increased or decreased. [0012] However, when the amount of ink under the master is small, there is a tendency for image defects to occur, and when there is a large amount, spot-like stains tend to occur. On the other hand, only by controlling the amount of ink under the master, It has also been found that the amount of ink under the master is one factor at a time, since image defects and spot-like stains cannot be resolved.

In other words, when we look at spot-like stains, (a) the amount of ink under the master is large (ii) the master tension is high (u) the flow resistance of the ink The lower the S, the more likely the spot-like stains occur. On the other hand, image loss tends to occur as (a) the amount of ink below the master is small.

[0013] Here, the master tension is caused by stress on the stencil sheet caused by the printing operation. When the tension is high, the internal pressure of the stencil sheet is relieved to try to relieve the ink from the perforated part. Becomes easier to stand out.

In addition, because the stencil sheet is in a state where a tension force S is applied, if the amount of ink under the master is too large, the ink tends to float from the perforated part in an attempt to relieve the internal pressure of the stencil sheet as described above. Become.

Furthermore, when the flow resistance of the ink is small, the ink tends to rise from the perforated part.

[0014] (a) The amount of ink under the master decreases as the pressing force (A) by the press roll increases, and the drum peripheral speed (B), ink viscosity (C), and stencil sheet thickness (D) The larger the is, the more it increases. (Ii) The master tension increases as the pressing force (A) by the press roll increases, and decreases as the drum peripheral speed (B) increases. The ink viscosity (C) and stencil sheet thickness (D) Is irrelevant. (U) The flow resistance of the ink is independent of the pressing force (A) by the press roll and the peripheral speed (B) of the drum, and increases as the ink viscosity (C) and the stencil sheet thickness (D) increase.

[0015] Based on the above considerations, the experiment was repeated mainly by obtaining conditions under which spot-like stains do not occur, and a relational expression that gives some correlation with the spot-like stains was studied. As a result, within the range where the following formula (1) is satisfied, (a) the amount of ink under the master, (ii) the master tension, and (u) the flow resistance of the ink are all adjusted appropriately, and the stencil It has been experimentally found that the ink under the base paper can be supplied and held in an appropriate amount and uniformly over the entire printing surface, and therefore can solve the problems of image defects and spot-like stains. (Equation 2)

130≤ ^ (B / A) X (C + 200) X ^ D≤400 (1)

In the above formulas, A is the pressing force (N) by the press roll, that is, the pressing force of the printing medium against the drum; B is the peripheral speed of the drum (mZs); C is the viscosity of the ink (mPa's); D Is the thickness m) of the stencil paper. The unit of the value (130, 400) of the formula is 10 ^_6 · π ^1/2 · kg ^1/2 's- ^{1 / 2} .

In printing using the RK machine, the pressing force by the press roll (A: N), the peripheral speed of the drum (B: m / s), the viscosity of the ink (C: mPa · s), and the thickness of the stencil paper (D : When m) satisfies the relationship of the formula (1), the ink can be uniformly distributed over the entire drum wall, and a uniform image can be obtained without image defects or spot-like stains.

[0016] In the above formula (1), even if the relationship between A, B, C, and D is below the lower limit of 130 or above 400, the occurrence of spot-like stains cannot be suppressed. Moreover, if this relational expression is satisfied, it is possible to suppress the occurrence of missing images at the same time.

Furthermore, in the formula (1), the relationship between A, B, C, and D: (BZA) ^1/2 X (C + 200) XD ^1/2 is more preferable than the power of 160 to 330! / ヽ.

[0017] The pressing force (A) by the press roll is preferably set to about 20 to 50N! /. When the pressing force is 20 N or more, it is preferable for the conveyance of the printing paper to be stable. On the other hand, if it exceeds 5 ON, noise and mechanical / electrical load increase, which is not preferable. On the other hand, if the pressing force is set too high, the stencil sheet tends to stretch, and as a result, the reproducibility of the printed material may be reduced.

[0018] The peripheral speed (B; mZs) of the drum corresponds to the printing speed. This peripheral speed (B) is 0.5 to 1.

It is preferably about 3 mZs. If the peripheral speed is higher than 1.3 mZs, noise and mechanical / electrical load increase, which is not preferable. Furthermore, if the peripheral speed is too high, the conveyance of the printing paper may not be stable when the printing paper is peeled off from the drum. On the other hand, if the peripheral speed is less than 0.5 mZs, the time efficiency of printing decreases, which is not preferable.

[0019] It is preferable that the viscosity (C: mPa's) of the ink is lower than that of the conventional ink. Specifically, the shear stress is measured from OPa at a speed of 0.1 PaZs at 23 ° C. The ink viscosity at lOPa when increasing the amount of calories is preferably 500 mPa · s or less, and 300 mPa · s or less. It is particularly preferable that it is less than or equal to lOOmPa's. On the other hand, the viscosity of the ink measured in the same manner is preferably 1.5 mPa's or more, more preferably 3. OmPa's or more, and even more preferably 5. OmPa's or more.

By setting the viscosity of the ink within the above range, it is possible to increase the ink penetration rate into the printing medium and easily improve the drying property of the printed matter.

The viscosity of conventional commercially available stencil printing emulsion inks is 1 million mPa's or more. In order to satisfy equation (1) using such a high viscosity ink, the pressing force (A) Needs to be in the tens of millions of N level, and it is not easy to add such a pressing force in reality.

[0020] The thickness (D) of the stencil sheet is preferably about 20 to 50 μm! /. If this thickness is less than 20 μm, the stiffness of the stencil sheet will be weak and the handling operability may be reduced. On the other hand, in view of the ink passage resistance from the perforated part of the stencil sheet and the image quality at the solid part, the thickness of the stencil sheet is preferably 50 μm or less.

Next, a stencil printing apparatus (RK apparatus) used in the present invention will be described with reference to the drawings.

1 to 7 show a first embodiment, FIG. 1 is a schematic configuration diagram of a stencil printing machine, FIG. 2 is a perspective view of a drum, FIG. 3 is a cross-sectional view taken along line A1-A1 in FIG. 2, and FIG. 2 is a cross-sectional view taken along line B1-B1 in FIG. 2, FIG. 5 is a plan view of the drum showing the ink supply unit, FIG. 6 is a cross-sectional view taken along line C1 C1 in FIG. 5, and FIG. FIG.

The stencil printing apparatus shown in this embodiment has an outer peripheral wall that is rotatable and formed of an ink impermeable member, and a drum on which a stencil sheet is mounted on the surface of the outer peripheral wall; There is an ink supply section upstream of the maximum printing area on the outer peripheral wall, and an ink supply means for supplying ink to the surface of the outer peripheral wall from the ink supply section, and a fed print medium to the outer peripheral wall. And a press roll for pressing.

As shown in FIG. 1, the stencil printing apparatus is mainly composed of a document reading unit 1, a plate making unit 2, a printing unit 3, a paper feeding unit 4, a paper discharging unit 5 and a plate discharging unit 6. It has been.

The original reading unit 1 includes an original setting table 10 on which an original to be printed is placed, a reflection type original sensor 11 and 12 that detects the presence of an original on the original setting table 10, and an original of the original setting table 10. Document transport rolls 13 and 14 for transporting the document, stepping motor 15 for rotating the document transport rolls 13 and 14, and image data of the documents transported by the document transport rolls 13 and 14 are optically read. A contact-type image sensor 16 that converts the signal into an electrical signal, and a document discharge tray 17 on which a document discharged from the document setting table 10 is placed. Then, the document placed on the document setting table 10 is transported by the document transport rollers 13 and 14, and the image sensor 16 reads the image data of the transported document.

The plate making unit 2 includes a base paper storage unit 19 that stores the rolled long stencil base paper 18, a thermal head 20 that is disposed downstream of the base paper storage unit 19, and the thermal head 20. A platen roll 21 arranged at a position, a pair of base paper feed rolls 22 and 22 arranged downstream of the transport of the platen roll 21 and the thermal head 20, and a light pulse motor that rotationally drives the platen roll 21 and the base paper feed roll 22 23 and a base paper cutter 24 disposed downstream of the pair of base paper feed rolls 22 and 22.

Then, the long stencil sheet 18 is conveyed by the rotation of the platen roll 21 and the base paper feed roll 22, and each point-like heating element of the thermal head 20 selectively generates heat based on the image data read by the image sensor 16. As a result, the stencil sheet 18 is thermally perforated to make a plate, and the stencil sheet 18 thus made is cut with a stencil sheet cutter 24 to produce a stencil sheet 18 having a predetermined length.

The printing unit 3 includes a drum 26 that rotates in the direction of arrow A in FIG. 1 by the driving force of the main motor 25, and a base paper clamp that is provided on the outer peripheral surface of the drum 26 and clamps the leading end of the stencil base paper 18. Part 27, a base paper check sensor 28 for detecting whether or not the stencil paper 18 is wound around the outer peripheral surface of the drum 26, a reference position detection sensor 30 for detecting the reference position of the drum 26, and a main motor 25 And a rotary encoder 31 for detecting the rotation of the motor. The rotation position of the drum 26 can be detected by detecting the output pulse of the rotary encoder 31 based on the detection output of the reference position detection sensor 30.

In addition, the printing unit 3 includes a press roll 35 disposed at a position below the drum 26. The press roll 35 is pressed against the outer peripheral surface of the drum 26 by the driving force of the solenoid device 36. The outer peripheral surface force of the drum 26 can also be shifted between the separated standby positions. The press roll 35 is in the pressing position during the printing mode period (including trial printing). It is always located in the printer, and is placed in the standby position during periods other than the print mode.

Then, the front end of the stencil sheet 18 conveyed from the plate making unit 2 is clamped by the stencil sheet clamp unit 27, and in this clamped state, the drum 26 is rotated and the stencil sheet 18 is wound around the outer peripheral surface of the drum 26, and the drum 26 The printing paper (printing medium) 37 fed from the paper feeding unit 4 in synchronism with the rotation of the paper is pressed against the stencil paper 18 mounted on the drum 26 by the press roll 35 to thereby apply the stencil paper to the printing paper 37. Ink 56 is transferred from 18 perforations and the image is printed.

[0026] The paper supply unit 4 includes a paper supply base 38 on which the print paper 37 is stacked, primary paper supply rolls 39 and 40 that convey only the uppermost print paper 37 from the paper supply base 38, and these 1 A pair of secondary paper feed rolls 41, 41 that convey printing paper 37 conveyed by the secondary paper feed rolls 39, 40 between the drum 26 and the press roll 35 in synchronization with the rotation of the drum 26, and the pair of 2 A paper feed sensor 42 that detects whether or not the printing paper 37 is transported between the next paper feed rolls 41 and 41 is provided. The primary paper feed rolls 39 and 40 are configured so that the rotation of the main motor 25 is selectively transmitted via the paper feed clutch 43.

The paper discharge unit 5 includes a paper separation claw 44 that separates the printed printing paper 37 from the drum 26, a conveyance path 45 through which the printing paper 37 separated from the drum 26 by the paper separation claw 44 is conveyed, A paper discharge tray 46 on which the print paper 37 discharged from the transport path 45 is placed is provided.

The stencil discharge unit 6 guides the tip of the stencil sheet 18 unclamped from the outer peripheral surface of the drum 26 and transports the guided stencil sheet 18 while being peeled off from the drum 26. The stencil box 48 for storing the stencil sheet 18 conveyed by the stencil conveying means 47 and the stencil sheet 18 conveyed into the stencil box 48 by the stencil conveying means 47 are pushed into the inside of the stencil box 48. And a discharged plate compression member 49.

As shown in FIG. 2 to FIG. 4, the drum 26 has a spindle 50 fixed to the apparatus main body H (shown in FIG. 1), and can freely rotate on the spindle 50 via bearings 51. A pair of supported side disks 52, 52 and a cylindrical outer peripheral wall 53 fixed between the pair of side disks 52, 52 are provided. The outer peripheral wall 53 is integrated with the pair of side disks 52, 52 by the rotational force of the main motor 25. It is designed to be driven by rolling. Further, the outer peripheral wall 53 is made of a material having rigidity and not allowing ink 56 to pass through! Depending on the type of ink-impermeable member, fluororesin processing such as Teflon (registered trademark) processing, nickel plating, nickel chrome plating, etc., for the purpose of forming the outer peripheral surface of the outer peripheral wall 53 into a cylindrical surface without unevenness, etc. Various known surface treatments such as molten zinc plating and anodizing treatment may be applied to the outer peripheral wall 53.

The base paper clamp part 27 is provided by using a clamping recess 53 a formed along the axial direction of the support shaft 50 of the outer peripheral wall 53. One end of the base paper clamp part 27 is rotatably supported by the outer peripheral wall 53, and protrudes from the outer peripheral wall 53 in the clamp release state indicated by the phantom line in FIG. 4, but in the clamp state indicated by the solid line in FIG. It is provided so as not to protrude from the wall 53. Therefore, the stencil sheet portion 27 can clamp the stencil sheet 18 without protruding onto the outer peripheral wall 53.

The outer peripheral wall 53 is rotated in the direction of arrow A in FIGS. 2 and 4, and a position slightly rotated from the base paper clamp portion 27 is a printing start point. Therefore, the rotation direction A becomes the printing direction M, and the area below the printing start point is the printing area. In the first embodiment, the maximum printing area is set to an area capable of A3 size printing. An ink supply unit 55A of the ink supply means 54 is provided upstream of the maximum printing process rear of the outer peripheral wall 53 in the printing direction M.

[0031] As shown in FIGS. 2 to 6, the ink supply means 54 includes an ink container 57 in which ink 56 is stored, an ink pump 58 that sucks the ink 56 in the ink container 57, and the ink pump. The first pipe 59 for supplying the ink 56 sucked by 58 and the other end of the first pipe 59 are connected, an ink passage 60 is formed inside, and a hole 61 is formed at a position opposed to 180 degrees. The rotary shaft 63, a rotary joint 63 that is rotatably supported on the outer peripheral side of the spindle 50 and has a communication hole 62 that can communicate with the hole 61, and one end connected to the rotary joint 63 and the other end. The second pipe 64 is guided to the outer peripheral wall 53, and the ink supply part 55A is opened at the other end of the second pipe 64.

[0032] The ink supply section 55A is opened with an ink diffusion groove 65 for diffusing the ink 56 from the second pipe 64 in the printing orthogonal direction N and an interval in the printing orthogonal direction N of the ink diffusion groove 65. The plurality of communication holes 66 and an ink supply port 55a serving as an ink diffusion supply unit that communicates with the plurality of communication holes 66 and is opened on the surface of the outer peripheral wall 53.

As shown in FIGS. 5 and 6, the ink diffusion groove 65, the plurality of communication holes 66, and the ink supply port 55a are formed along the direction orthogonal to the printing direction M of the outer peripheral wall 53 (that is, the printing orthogonal direction N). The ink supply recess 67 is formed by an ink supply member 68 disposed therein. The ink supply ports 55a are formed along the printing orthogonal direction N, and supply the ink 56 almost uniformly in the printing orthogonal direction N of the outer peripheral wall 53.

Next, the operation of the stencil printing apparatus having the above configuration will be briefly described.

First, when the plate making mode is selected, the plate making unit 2 conveys the stencil sheet 18 by the rotation of the platen roll 21 and the base paper feed roll 22, and a number of thermal heads 20 are based on the image data read by the document reading unit 1. When the stencil sheet 18 is selectively heated, the stencil sheet 18 is thermally perforated to make a plate, and a predetermined portion of the stencil sheet 18 is cut with a stencil sheet cutter 24 to produce a stencil sheet 18 having a desired size.

[0034] In the printing unit 3, the tip of the stencil sheet 18 made by the plate making unit 2 is clamped by the stencil sheet clamping unit 27 of the drum 26, and in this clamped state, the drum 26 is rotated to remove the stencil sheet 18 from the drum 26. Wrap around the outer peripheral surface of the plate.

Next, when the printing mode is selected, the drum 26 is driven to rotate in the printing unit 3 and the driving of the ink supply means 54 is started. Then, the ink 56 is supplied to the outer peripheral wall 53 from the ink supply port 55a, and the supplied ink 56 is held between the outer peripheral wall 53 and the stencil sheet 18, and the press roll 35 is pressed to the pressing position. Is displaced.

In synchronization with the rotation of the drum 26, the paper feeding unit 4 feeds the printing paper 37 between the drum 26 and the press roll 35. The fed printing paper 37 is pressed against the outer peripheral wall 53 of the drum 26 by the press roll 35 and is conveyed by the rotation of the outer peripheral wall 53 of the drum 26. That is, the printing paper 37 is conveyed while being in close contact with the stencil paper 18.

In parallel with the conveyance of the printing paper 37, as shown in FIG. 7, the ink 56 held between the outer peripheral wall 53 of the drum 26 and the stencil paper 18 is caused by the pressing force of the press roll 35. While being squeezed, it is diffused downstream in the printing direction M, and the diffused ink 56 oozes out from the perforations of the stencil sheet 18 and is transferred to the printing sheet 37 side. With the above, printing paper 37 Ink images are printed in the process of passing between the outer peripheral wall 53 of the drum 26 and the press roll 35. The printing paper 37 that has passed between the outer peripheral wall 53 of the drum 26 and the press roll 35 is peeled off from the drum 26 by the paper separation claw 44, and the printing paper 37 separated from the drum 26 passes through the conveyance path 45. Then, the paper is discharged onto a paper discharge tray 46 and stacked there.

[0037] When printing of the set number of prints is completed, the rotation of the outer peripheral wall 53 of the drum 26 is stopped and the drive of the ink supply means 54 is stopped. As a result, the supply of the ink 56 to the outer peripheral wall 53 is stopped. Further, the press roll 35 is returned to the standby position after the pressing position, and the standby mode is entered.

When the evacuation mode is selected, for example, by starting a new plate-making process, the base paper clamp part 27 of the drum 26 is displaced to the clamp release position, and the tip side force of the stencil paper 18 that has been released from the clamp S As the drum 26 rotates Then, it is guided by the discharge plate conveying means 47 and stored in the discharge plate box 48.

As described above, in this stencil printing apparatus, the ink 56 is supplied to the outer peripheral wall 53 of the drum 26, and the ink 56 is diffused on the outer peripheral wall 53 by being squeezed by the pressing force of the press roll 35. The diffused ink 56 is transferred to the printing paper 37 from the perforation of the stencil sheet 18 by the pressing force of the press roll 35. Therefore, when the printing mode is completed, the ink 56 supplied to the drum 26 is held in a substantially sealed space between the outer peripheral wall 53 of the drum 26 and the stencil paper 18, and contact with the atmosphere is minimized. . As a result, it is possible to reliably prevent the deterioration of the ink 56 that does not cause the ink 56 to change even if printing is not performed for a long time. Also, it is not necessary to arrange various rolls for supplying ink inside the drum 26 as in the conventional example. Thereby, the drum 26 can be further reduced in size and weight.

[0039] Further, since the outer peripheral wall 53 of the drum 26 only needs to be formed of an ink impermeable member, the choice of materials can be expanded, and a simple structure can be used, so that it can be manufactured at low cost. Further, since the strength of the drum 26 can be easily increased, it is possible to prevent image unevenness due to fluctuations in printing pressure.

[0040] Furthermore, the ink 56 is basically subjected to printing in the best condition with almost no deterioration because contact with the atmosphere is minimized. In addition, since it is not necessary to manage the prevention of ink 56 deterioration, it is not necessary to prevent the ink 56 from dripping down. Can be spread.

In the first embodiment, since the base paper clamp part 27 does not protrude from the surface of the outer peripheral wall 53 of the drum 26, the press roll 35 can be driven easily. That is, it is not necessary to displace the press roll 35 between the pressing position and the standby position every time the drum 26 rotates in order to avoid the press roll 35 from colliding with the base paper clamp unit 27 in the printing mode. As a result, it is possible to eliminate problems such as noise caused by the press roll 35 and image quality degradation due to rebound.

8 and 9 show a modification of the ink supply unit, FIG. 8 is a plan view of a part of the drum showing the ink supply unit, and FIG. 9 is a cross-sectional view taken along line C4 C4 in FIG. .

As shown in FIGS. 8 and 9, the ink supply unit 55D of this modification includes an ink diffusion groove 65 that diffuses the ink from the second pipe 64 in the printing orthogonal direction N, and the printing orthogonality of the ink diffusion groove 65. And a plurality of ink supply ports 55d as ink diffusion supply portions having one end opened at equal intervals in the direction N and the other end opened on the surface side of the outer peripheral wall 53. The ink diffusion groove 65 and the ink supply port 55d are formed by an ink supply recess 67 formed along the printing orthogonal direction N of the outer peripheral wall 53, and an ink distribution member 68 disposed inside the ink supply recess.

[0043] In the ink supply section 55D of this modified example, the ink 56 is supplied onto the outer peripheral wall 53 in a state of being evenly distributed in the entire peripheral direction of each ink supply port 55d, and the direct printing of the outer peripheral wall 53 is performed. When the cross direction N is viewed as a total, the ink 56 is supplied almost uniformly in the printing orthogonal direction N.

In the ink supply unit 55D of this modification, the press roll 35 does not fall into the ink supply port 55d when passing over the ink supply port 55d. Accordingly, it is possible to prevent the press roll 35 from falling down and generating vibrations.

[0044] As a second embodiment, in this stencil printing apparatus, an ink leakage prevention groove is provided on the outer peripheral wall at a position outside the maximum printing process rear and covered with the stencil sheet. Is preferred. As a result, if ink between the outer peripheral wall and the stencil sheet leaks outside the maximum printing area, the leaked ink force enters the ink leakage prevention groove, ensuring that the ink leaks from the edge of the stencil sheet. Can be prevented. [0045] Further, the ink leakage prevention groove is provided at the left and right outer positions in the direction orthogonal to the printing from the maximum printing rear in order to surely prevent ink leakage due to the side force of the outer peripheral wall; In order to reliably prevent ink leakage from the end of the printer, it must be installed at a position downstream of the maximum printing process rear; to reliably prevent ink leakage from the top of the outer peripheral wall (so as to It is possible to prevent clamping failure, poor printing, stencil paper wrinkles, etc. due to ink smudged in the ink.), Provided upstream of the ink supply part upstream of the maximum printing area; In order to prevent ink leakage more reliably, and to make each ink leakage prevention groove narrow and prevent the stencil sheet from falling into the ink leakage prevention groove, a plurality of ink leakage prevention grooves should be provided. But it preferred, respectively,.

FIGS. 10 to 13 show the second embodiment, FIG. 10 is a perspective view of the drum, FIG. 11 is a cross-sectional view taken along line A2-A2 in FIG. 10, and FIG. 12 is B2-B2 in FIG. FIG. 13 is a schematic view of the outer peripheral wall of the drum developed along the line.

As shown in FIGS. 10 to 13, in this second embodiment, the ink leakage prevention groove 7 1 is positioned outside the maximum printing area S of the outer peripheral wall 53 of the drum 26 and covered with the stencil sheet 18. Is provided. Further, the ink leakage prevention groove 71 is provided at the left and right outer positions in the printing orthogonal direction N from the maximum printing process rear S. Further, the ink leakage prevention groove 71 is continuously formed along the printing direction M, and is formed over a wider range than the printing direction M of the maximum printing process rear S. In other words, if the ink 56 diffuses directly from the ink diffusion groove 65 or the ink supply port 55a, the tip of the ink leakage prevention groove 71 is placed at least at the same Cf as the ink supply position in the drum rotation direction so that it does not leak. It is desirable that power is installed. The ink leakage prevention groove 71 is disposed about 10 mm outside the width of the ink diffusion groove 65 and the ink supply port 55a of the ink supply part 55A. Since other configurations are the same as those of the first embodiment, the same components are denoted by the same reference numerals and detailed description thereof is omitted.

[0047] Even in the second embodiment, as in the first embodiment, the ink 56 does not deteriorate even if printing is not performed for a long time, and the drum 26 is small and light. Can do.

In the second embodiment, since the ink leakage prevention groove 71 is provided at the left and right outer positions in the printing orthogonal direction N from the maximum printing process rear S, the maximum printing process rear S of the outer peripheral wall 53 is provided. Since the ink 56 leaking in the printing orthogonal direction N enters the ink leakage prevention groove 71, ink leakage from the side of the outer peripheral wall 53 can be prevented more reliably.

[0048] As a third embodiment, it is preferable that the stencil printing apparatus has an ink collecting means for collecting ink that has flowed out of the outer peripheral wall from the maximum printing area. As a result, excess ink can be removed from the outer peripheral wall of the drum, and ink can be reused.

[0049] Further, the ink collecting means removes the ink that has flowed downstream from the outer peripheral wall of the drum by pressing the press roll, and reuses it by removing it from the maximum printing area of the outer peripheral wall. It is more preferable to have an ink collection groove at the position, and to collect the ink collected in the ink collection groove, and to arrange a drop-preventing member capable of distributing ink in the ink collection groove. This sag prevention member can prevent stencil paper strength S ink collection grooves that do not fall into the stencil paper strength S ink collection groove from lowering the recovery efficiency due to blocking the ink collection path of the stencil recovery grooves. In addition, ink flows smoothly into the ink collection groove by pressing the stencil paper ink at the location where it does not stick to the edge of the stencil printing ink collection groove and the ink is smoothly sealed. Does not occur. In addition, press roll force S does not fall into the ink collection groove when passing over the ink collection groove, so that it is possible to prevent the press roll from falling down and generating vibrations.

The sagging prevention member preferably forms the same peripheral surface as the outer peripheral wall of the drum. Thereby, since the press roll moves on substantially the same circumference, the falling sound and vibration of the press roll can be completely prevented. In addition, the ink collection means uses the ink leakage prevention groove as the ink collection groove to reliably remove the ink collected in the ink leakage prevention groove and reuse the ink, and the ink collected in the ink leakage prevention groove. It is preferable to recover.

14 to 16 show the third embodiment, FIG. 14 is a perspective view of the drum, FIG. 15 is a cross-sectional view taken along the line A3-A3 in FIG. 14, and FIG. 16 is a line B3-B3 in FIG. FIG.

As shown in FIGS. 14 to 16, in the third embodiment, compared with the first embodiment, an ink collecting means 73A for collecting the ink 56 leaked from the maximum printing rear S of the outer peripheral wall 53 is added. Has been. [0051] The ink collecting means 73A includes an ink leakage prevention groove 72 formed downstream of the largest printing process rear S of the outer peripheral wall 53, and a third noise that has one end of the ink leakage prevention groove 72 opened. 74 and a rotary joint 63 in which the other end of the third pipe 74 is connected and a communication hole 75 is formed, a hole 76a in which the rotary joint 63 is rotatably supported and the communication hole 75 can be connected, and an internal A support shaft 50 having an ink passage 76b formed therein, a fourth pipe 77 having one end connected to the support shaft 50, and a filter 80 interposed in the middle of the fourth pipe 77 to trap paper dust and the like. Ink pump (for example, trochoid pump) 78 that is interposed in the middle of the fourth pipe 77 and sucks the ink 56 in the fourth pipe 77, and a collection container 79 to which the other end of the fourth pipe 77 is connected It has been.

The arrangement position of the ink leakage prevention groove 72 is continuously formed along the printing orthogonal direction N at the printing downstream position from the maximum printing process rear S. However, since the one end of the third pipe 74 is connected, the ink leakage prevention groove 72 is formed by using the ink collection recess 81 and the pipe fixing member 82 disposed inside the ink recovery recess 81. The rotary joint 63 is also used as the ink supply means 54. Since the spindle 50 is also used in the ink passage of the ink supply means 54, it has a double pipe structure. Since other configurations are the same as those of the first embodiment, the same components are denoted by the same reference numerals and detailed description thereof is omitted.

[0053] Even in the third embodiment, as in the first embodiment, the ink 56 does not change in quality even if printing is not performed for a long time, and the drum 26 is small and lightweight. Can do.

In the third embodiment, since the ink collecting means 73A for collecting the ink 56 leaking outside the maximum printing area S of the outer peripheral wall 53 is provided, the excess ink 56 is removed from the outer peripheral wall 53 of the drum 26. In addition, the ink 56 can be reused.

In the third embodiment, since the ink container 57 for supplying ink and the recovery container 79 for collecting ink are respectively provided, the recovered ink can be prevented from being reused.

In the third embodiment, since the filter 80 is interposed in the middle of the fourth pipe 77 of the ink recovery means 73A, the ink 56 that is not mixed with paper dust or the like can be reliably returned to the recovery container 79. Therefore, it contributes to improving the quality of the recovered ink. However, the filter 80 may be an embodiment that is not indispensable for reusing ink and is not installed.

In the third embodiment, the ink supply means 54 and the ink recovery means 7 are used in the printing mode. If 3A is controlled so that it is always driven, ink is continuously supplied from the ink supply section 55A to the outer peripheral wall 53 in the printing mode, and the ink 56 that has entered the ink leakage prevention groove 72 from the outer peripheral wall 53 is supplied. Since it is always collected, it is possible to prevent the ink 56 from staying on the outer peripheral wall 53 as much as possible. In addition, an appropriate amount of ink 56 can be held on the outer peripheral wall 53 at all times. For this reason, a printed matter having a desired ink density can be obtained even during a large amount of continuous printing. The arrangement of the ink leakage prevention grooves 72 may be the arrangement as in the second embodiment.

FIGS. 17 (a) to 17 (c) show modified examples of the ink leakage prevention groove, FIG. 17 (a) is a sectional view of the vicinity of the ink leakage prevention groove, and FIG. 17 (b) is a view of the vicinity of the ink leakage prevention groove. A partial plan view, FIG. 17 (c) is a sectional view for explaining the behavior of the stencil sheet.

As shown in FIGS. 17 (a) and 17 (b), as a modification, it is preferable that a spiral ring member 92 as a sag preventing member 72 is fixed inside the ink leakage preventing groove 72. Specifically, the spiral ring member 92 is fixed by being press-fitted into the ink leakage prevention groove 72 using its panel property. The upper surface height of the spiral ring member 92 is set to be the same as or slightly lower than the surface of the outer peripheral wall 53. Since the other configurations are the same, the same reference numerals are given to the same components in the drawings, and detailed description will be omitted.

In this modified example, as shown in FIG. 17 (a), the stencil sheet 18 does not fall into the ink leakage preventing groove 72 due to the suction force of the ink collecting means. Accordingly, it is possible to prevent the recovery efficiency from being lowered due to the stencil sheet 18 blocking the ink recovery path of the ink leakage prevention groove 72. In addition, as shown in FIG. 17 (c), the stencil sheet 18 sticks to the edge of the ink leakage prevention groove 72, and the stencil sheet 18 does not seal the ink at that location. Flows smoothly into the ink leakage prevention groove 72, so ink leakage does not occur. Further, since the press roll 35 does not fall into the ink leakage prevention groove 72 when passing over the ink leakage prevention groove 72, the falling sound and vibration of the press roll 35 can be prevented.

FIG. 18 shows a fourth embodiment of the stencil printing apparatus, and is a schematic view in which the outer peripheral wall of the drum is developed. As shown in the figure, in this embodiment, the ink collecting means 73D has an ink collecting groove 94 at a printing downstream position from the maximum printing rear S of the outer peripheral wall 53 of the drum. The ink collected in the collecting groove 94 is collected. In other words, the ink leakage prevention groove 72 is not used to collect the ink that has flowed outside the maximum printing area S. The ink collection groove 94 is used to circulate the ink that has flowed downstream from the maximum printing area S. I have earned.

Thus, instead of the ink leakage prevention groove 72, the ink recovery groove 94 can be provided at the same position. The ink collecting grooves 94 are constituted by a large number of openings 94a formed in two rows in the printing direction M and at intervals in the printing orthogonal direction N.

In the fourth embodiment, the ink force S that has flowed out to the downstream side of the printing by pressing the press roll is removed from the outer peripheral wall 53 of the drum, and the ink can be reused. Further, the stencil sheet 18 does not fall into the ink collecting groove 94 due to the suction force of the ink collecting means 73D. Therefore, it is possible to prevent a reduction in recovery efficiency due to the stencil sheet 18 blocking the ink recovery path of the ink recovery groove 94. In addition, because the stencil paper 18 sticks to the edge of the ink collecting groove 94 and the stencil paper 18 does not seal the ink at that location, the ink smoothly flows into the ink collecting groove 94 by the ironing of the press roll. There is no leakage at the end. Further, since the press roll does not fall into the ink collection groove 94 when passing over the ink collection groove 94, the press roll 35 can be prevented from generating a drop sound and vibration.

[0059] As a fifth embodiment, this stencil printing apparatus has ink amount adjusting means for controlling the ink supply amount in the printing orthogonal direction from the ink supply unit, and this ink amount according to the perforation rate of the stencil sheet. It is preferable to control the adjusting means. As a result, the ink supply can be increased in the section with a high perforation rate, the ink supply can be reduced in the section with a low perforation rate, and the required amount of ink can be supplied to the required section. Ink supply can be prevented as much as possible. That is, efficient ink diffusion can be performed.

[0060] Furthermore, it is preferable to have an ink amount adjusting means for controlling the ink supply amount in the direction orthogonal to the printing of the ink supply force, and to control the ink amount adjusting means according to the size of the printing medium to be fed. As a result, ink can be supplied only to the necessary section, such that ink is supplied in the section where the print medium is present, and ink is not supplied in the section where the print medium is not present. Ink supply can be prevented as much as possible. In other words, good efficiency V, ink diffusion can be performed.

FIGS. 19 to 21 show the fifth embodiment, FIG. 19 is a sectional view of the drum, FIG. 20 is an explanatory view showing a state in which the maximum printing area is divided into six divided areas, and FIG. 21 is a control block. As shown in FIG. 19, in this fifth embodiment, the ink supply to the ink supply section 55A is performed through the ink supply passages 83a to 83f arranged at equal intervals in the printing orthogonal direction N, The ink supply passages 83a to 83f are provided with control valves 84a to 84f for controlling the ink flow rate. The six ink supply passages 83a to 83f and the control valves 84a to 84f are arranged at the upstream position when the maximum printing rear of the outer peripheral wall 53 is divided into six in the printing orthogonal direction N, and each divided area E1 to E6 ( It is almost in charge of the ink supply (shown in Fig. 20). That is, the six control valves 84a to 84f constitute an ink amount adjusting means for controlling the ink supply in the printing orthogonal direction N from the ink supply unit 55A. The opening / closing amounts of the control valves 84 a to 84 f are controlled by the valve controller 85.

On the other hand, as shown in FIG. 21, the fifth embodiment includes a punching rate analysis unit 86, and the punching rate analysis unit 86 is divided into divided areas E 1 to E 6 based on image data from the document reading unit 1. The degree of perforation rate is detected. The controller 87 outputs an open / close state command to the valve controller 85 in accordance with the degree of the perforation rate. Specifically, if the piercing rate is high, the valve opening amount is increased, and if the piercing rate is low, a command to reduce the valve opening amount is sent. Since other configurations are the same as those of the first embodiment, the same components are denoted by the same reference numerals and detailed description thereof is omitted.

[0063] Even in the fifth embodiment, as in the first embodiment, the ink 56 does not change in quality even if printing is not performed for a long time, and the drum 26 is small and lightweight. Can do. Further, in the fifth embodiment, there are a plurality of control valves 84a to 84f capable of controlling the ink supply amount in the printing orthogonal direction N from the ink supply unit 55A, and according to the hole area ratio of the stencil sheet 18. Since each control valve 84a to 84f is controlled, the ink supply amount is increased in the section where the perforation rate is high, and the ink supply amount is decreased in the section where the perforation ratio is low. Ink 56 can be supplied in the amount required for Key supply can be prevented as much as possible. In other words, efficient ink diffusion can be performed and the probability of ink leakage can be kept low.

FIG. 22 is a control block diagram showing a modification of the fifth embodiment.

In this modification, paper size detecting means 88 is provided, and this paper size detecting means 88 detects the paper size (paper width) of the printing paper set on the paper supply stand. The control unit 87 outputs an open / close command to the valve controller 85 in accordance with the detection result (paper size) from the paper size detection means 88. Specifically, a command is sent to set the control valve to the open position in the divided area where the printing paper exists, and to set the control valve to the closed position in the divided area when there is no printing paper. Since other configurations are the same as those of the fifth embodiment, detailed description thereof is omitted.

[0065] This modification has a plurality of control valves that can control the ink supply amount of the ink supply force in the printing orthogonal direction, and control each control valve according to the size of the printing paper to be fed. Therefore, ink 56 is supplied in the section where the printing paper is present, and ink 56 is not supplied in the section where the printing paper is not present. Ink supply can be prevented as much as possible. In other words, efficient ink diffusion can be performed and the probability of ink leakage can be kept low. Note that the control according to the punching rate of the fifth embodiment and the control according to the paper size of the modification of the fifth embodiment may be performed together.

[0066] As a sixth embodiment, in the stencil printing apparatus, it is preferable that the ink supply means and the ink recovery means are always driven in the printing mode. As a result, ink is continuously supplied from the ink supply unit to the outer peripheral wall during the printing mode, and the ink that has entered the ink leakage prevention groove from this outer peripheral wall is always collected, so that the ink stays on the outer peripheral wall. Can be prevented. In addition, since an appropriate amount of ink can always be held on the outer peripheral wall, a printed matter having a desired ink density can be obtained even during a large amount of continuous printing.

[0067] As a seventh embodiment, in the stencil printing apparatus, the width of the press roll is an ink leakage prevention groove provided at each of the left and right outer positions in the printing orthogonal direction, and both of these ink leakage prevention It is preferable that the width is set so as to press the inner side of each outer edge of the groove. Thereby, since the press roll force ink leakage prevention groove is not pressed in a sealed state, It is possible to prevent the ink in the ink leakage prevention groove from leaking to the outside of the ink leakage prevention groove due to the pressing of the press roll. Also, if the ink collecting means force S is configured to collect ink in the ink leakage prevention groove with suction force, press roll force S outside the ink leakage prevention groove, so that it does not press outside. The leaked ink is not pressed by the press roll, and the probability that the leaked ink is collected again in the ink leakage prevention groove by the suction of the ink collecting means is increased.

FIG. 23 shows the seventh embodiment, and is a front view of the drum and the press roll. As shown in FIG. 23, in this seventh embodiment, the width D of the press roll 35 is the ink leakage prevention grooves 71 and 71 provided at the left and right outer positions in the printing orthogonal direction N, respectively. It is set to press inside the outer edge 71 of each of the ink leakage prevention grooves 71, 71! That is, the width D of the press roll 35 is set to a dimension between the width of the maximum printing process rear S and the outer edge widths of the left and right ink leakage prevention grooves 71 and 17.

In the seventh embodiment, since the press roll 35 does not press the entire width of the ink leakage prevention grooves 71, 71, the ink in the ink leakage prevention grooves 71, 71 is not pressed by the press roll 35. It is possible to prevent a situation of leaking outside the leakage prevention grooves 71 and 71. Ink collection means force S Ink leakage prevention grooves 71 and 71 are configured to collect ink with suction force, so the press roll 35 does not press outside the ink leakage prevention grooves 71 and 71, preventing ink leakage. The ink leaking to the outside of the grooves 71, 71 is not pressed by the press roll 35, and the probability that the leaked ink is collected again in the ink leakage prevention grooves 71, 71 by the suction of the ink collecting means is increased.

[0070] As another stencil printing apparatus, for example, it has a peripheral wall on which a stencil sheet is mounted on its surface and does not pass through the peripheral wall force ink. Each of which has a porous sheet member disposed on the surface of the largest printing process rear, and a drum in which an ink passage is provided at least over the entire area of the largest printing processer between the porous member and the base wall. A stencil provided with an ink supply means for supplying ink to the ink passage, an ink collection means for collecting the ink in the ink passage, and a press roll for pressing the fed printing medium against the outer peripheral wall A printing device can also be used.

[0071] The stencil printing method according to the present invention is performed using the stencil printing apparatus described above, and has been made a plate. The drum loaded with the stencil sheet is pressed with a press roll while rotating, so that the ink passes through the perforated portion of the stencil sheet already made and is transferred to the printing medium. The details of each process are as described in the description of the stencil printing apparatus.

Next, the ink used in the stencil printing method according to the present invention will be described.

The form of the ink is not particularly limited, but is preferably a water-based ink form. The water contained in the ink evaporates into the atmosphere immediately after printing, and further, the ink is pressed between the fibers of the printing paper and penetrates during printing, so that the ink and air are separated inside the printing paper. Since the interface spreads rapidly and water tends to evaporate, the dryness of the printed matter can be further improved.

In the case of water-based inks, it is preferable to include water, a colorant, and a spinnability imparting agent!

[0073] From the viewpoint of improving the drying property of the printed matter, water is preferably contained in an aqueous ink in an amount of 50% by weight or more, more preferably 65% by weight or more. On the other hand, the upper limit of the blending amount of water may be set as appropriate from the balance with other blending components that are not particularly limited, and is preferably about 80% by weight or less, for example.

In the stencil printing apparatus, the ink inside the printing press is hermetically sealed to prevent moisture from evaporating into the atmosphere, so that it is also suitable for use with high water content water-based inks.

[0074] As the colorant of the ink, a pigment or a dye can be used, and two or more kinds may be used in combination. Examples of pigments include organic pigments such as azo, phthalocyanine, dye, condensed polycyclic, nitrogen, nitroso, etc. , Phthalocyanine green, alkali blue, ash phosphorus black, etc.); metals such as cobalt, iron, chromium, copper, zinc, lead, titanium, vanadium, manganese, nickel, metal oxides and sulfur In addition, inorganic pigments such as clay, ocher, ultramarine, and bitumen, and carbon blacks such as furnace carbon black, lamp black, acetylene black, and channel black can be used. Examples of the dye include water-soluble dyes such as basic dyes, acid dyes, direct dyes, soluble vat dyes, acid mordant dyes, mordant dyes, reactive dyes, vat dyes, and sulfur dyes, and water-soluble by reduction. The water-soluble dye which became can be used. Either pigment or dye, or both, can be used as a colorant. It is preferable because it can be made into an ink with excellent weather resistance with little smearing.

[0075] The content of the colorant in the ink is usually 1 to 20% by weight, and preferably 3 to 15% by weight. In order to further increase the printing density of the printed matter, it is more preferable to contain 5% by weight or more.

[0076] As described above, the viscosity of the ink is preferably lower than that of the conventional ink. Specifically, the shear stress is increased from OPa at a rate of 0.1 PaZs at 23 ° C. It is preferable that the viscosity of the ink in lOPa is 500 mPa's or less, more preferably 300 mPa-s or less, and particularly preferably lOOmPa's or less. On the other hand, the ink viscosity measured in the same manner is preferably 1.5 mPa's or more. 3. More preferably, it is more than OmPa's. 5. More preferably, it is more than OmPa's. .

[0077] It is preferable that the ink is mixed with a water-soluble organic solvent from the viewpoint of preventing drying at the perforated portion of the stencil sheet during printing.

As the water-soluble organic solvent, an organic compound that is liquid at room temperature and is soluble in water is used. For example, lower alcohols such as methanol, ethanol, 1 propanol, isopropanol, 1 butanol, 2-butanol, isobutanol, 2-methyl-2-propanol; ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol , Propylene glycol, dipropylene glycol, tripropylene glycol and the like glycols; glycerin; acetins (monoacetin, diacetin, triacetin); Noremonopropinoreethenole, triethyleneglycolenobutinoreether, tetraethyleneglycololemonomethinore Derivatives of glycols such as tetraethyleneglycolenomonoethylenate ether, tetraethyleneglycolonemethyl ether, tetraethyleneglycol jetyl ether; triethanolamine, 1-methyl-2-pyrrolidone, j8-thiodiglycol Can use sulfolane. Average molecular weight 200, 300, 400, 600, etc. Average molecular weight force Polyethylene glycol in the range of 190-630, average molecular weight 400, etc., average molecular weight 20 A low molecular weight polyalkylene glycol such as a diol type polypropylene glycol in the range of 0 to 600, a triol type polypropylene glycol having an average molecular weight in the range of 250 to 800, such as an average molecular weight of 300 or 700, and the like can also be used. These water-soluble organic solvents can be used alone or in combination of two or more.

[0078] The content of the water-soluble organic solvent in the ink is preferably 5% by weight or more, more preferably 10% by weight or more as the total content when two or more kinds are used. I like it. The upper limit of the content is not particularly limited, but is preferably about 45% by weight or less and more preferably about 35% by weight or less in order to reduce the back-through of the image. By containing 5% by weight or more of a water-soluble organic solvent having a boiling point higher than that of water, more preferably a boiling point of 150 ° C. or higher, drying of the perforated portion of the stencil sheet during printing can be effectively prevented.

[0079] The ink preferably contains a spinnability imparting agent capable of imparting appropriate spinnability to the ink. Among these, since the spinnability of the ink can be appropriately controlled, the unsaturated carboxylic acid-based water-soluble polymer of the linear structure type, the polyalkylene oxide having a molecular weight of 50,000 or more, and the linear structure type One or more of (meth) acrylamide water-soluble polymers can be preferably used. Here, in this specification, acrylic acid or methacrylic acid is collectively referred to as “(meth) acrylic acid”, and (meth) acrylamide means acrylamide and methacrylamide.

Examples of the linear structure type unsaturated carboxylic acid-based water-soluble polymer include branched units containing a repeating unit represented by the following general formula (1), such as a linear structure type unsaturated carboxylic acid-based water. Soluble polymers are preferred.

[Chemical 1]

(Where R ¹ , R ² and IT are independently H, CH, (CH) nCOOH (n is an integer of 0 or 1).

3 2

Number). ) [0080] Here, when two or more carboxyl groups are contained, they may form an acid anhydride. In the case of a copolymer, the copolymerization mode may be a random, alternating, block type, etc.! /.

Examples of the unsaturated carboxylic acid-based water-soluble polymer include one or more unsaturated carboxylic acids selected from the group consisting of (meth) acrylic acid, maleic anhydride, maleic acid, fumaric acid, crotonic acid and itaconic acid. Examples thereof include water-soluble polymers containing an acid in the main chain, and salts thereof are also included. When this unsaturated carboxylic acid-based water-soluble polymer is dissolved in water, it becomes a super multivalent ionic polymer having a large number of negative charges, and this strong, ionic atmosphere and linear polymer provide a three-dimensional structure. It is thought that the effect of imparting the spinnability is caused by entanglement.

[0081] More specifically, poly (meth) acrylic acid, acrylic acid-methacrylic acid copolymer, (meth) acrylic acid maleic acid copolymer, (meth) acrylic acid-sulfonic acid monomer copolymer, (meta ) Acrylic acid-itaconic acid copolymer, (meth) acrylic acid ester-maleic acid copolymer, (meth) acrylic acid (meth) acrylamide copolymer, (meth) acrylic acid (meth) acrylic acid ester copolymer (Meth) acrylic acid vinylpyrrolidone copolymer, polymaleic acid, polyfumaric acid, polycrotonic acid, polyitaconic acid, maleic anhydride-alkyl butyl ether copolymer, and salts thereof.

The salt is preferably a monovalent metal salt or an ammine salt. For example, if it is poly (meth) acrylic acid, these salts include sodium poly (meth) acrylate, potassium poly (meth) acrylate, poly (meth) Ammonium acrylate, poly (meth) acrylic acid triethanolamine and the like can be mentioned. Other preferable examples include sodium polyitaconate, sodium polymaleate, sodium acrylic acid-methacrylic acid copolymer, sodium acrylic acid / maleic acid copolymer, sodium acrylic acid acrylamide copolymer, and the like.

[0082] When these unsaturated carboxylic acid-based water-soluble polymers are of an unneutralized type, usually, in the ink, together with these water-soluble polymers, sodium hydroxide, potassium hydroxide hydroxide, Alkaline neutralizing agents such as ammonia water, triethanolamine and diisopropanolamine are added. When neutralized salts of unsaturated carboxylic acid-based water-soluble polymers are used, it is not necessary to add these alkaline neutralizers!

[0083] If the unsaturated carboxylic acid-based water-soluble polymer is a linear structure type, the compound of the same molecular structure When compared among the products, the higher the weight average molecular weight, the longer the ink string length, and the lower the content in the ink, the lower the ink viscosity.

Among the above unsaturated carboxylic acid-based water-soluble polymers, unsaturated carboxylic acid monomers (acrylic acid, methacrylic acid, crotonic acid, etc.) can be increased without increasing the viscosity of the ink. , Itaconic acid, maleic acid, maleic anhydride, fumaric acid) polymers (homopolymers or copolymers) and salts of these polymers are preferably used, and polyacrylic acid and its A salt is particularly preferably used.

[0084] Unsaturated carboxylic acid-based water-soluble polymers including polyacrylic acid and salts thereof are preferably those having a weight average molecular weight of 10,000 or more, more preferably 100,000 or more, and more preferably 600,000 or more. Those having more than 1.2 million are particularly preferred. If the molecular weight is less than 10,000, it is necessary to contain a lot of unsaturated carboxylic acid-based water-soluble high molecules in order to increase the thread length of the ink, and as a result, it becomes difficult to make the ink low viscosity. . The molecular weight is preferably 10 million or less, more preferably 6 million or less. If the molecular weight exceeds 10 million, it is possible to increase the thread length of the ink with a small amount of content, but in order to obtain a thread length that is not too large, the content must be made very small. It becomes difficult to obtain stable ink properties.

[0085] As the alkylene group of the polyalkylene oxide, an ethylene group, a propylene group, a propylene group, or the like is preferably used. It may contain a single alkylene group or may contain multiple types of alkylene groups. Specifically, polyethylene oxide and ethylene oxide-propylene oxide copolymer can be preferably used, and polyethylene oxide is particularly preferably used. In the case of an ethylene oxide propylene oxide copolymer, the polymerization ratio (molar ratio) of ethylene oxide is 0.5 or more, preferably S, and more preferably 0.8 or more.

The molecular weight (weight average molecular weight) of the polyalkylene oxide is selected to be 50,000 or more in order to obtain the effect of controlling the transfer amount of the low viscosity ink, and preferably 300,000 or more. More preferably it is. On the other hand, the upper limit of the molecular weight is not particularly limited, but it is preferably 10 million or less. It is preferable to be about 8 million or less.

Polyalkylene oxide is a polymer with a linear structure. When dissolved in water, polyalkylene oxide has a high degree of freedom in the intramolecular bond angle provided by the molecular structure, and a three-dimensional structure provided by the structure of a linear polymer. It exhibits unique behavior in water because of its entanglement and affinity for water molecules brought about by the polarity of oxygen atoms.

[0086] "Linear structure type" of (meth) acrylamide water-soluble polymer means no branched chain (branched), cross-linked structure or cyclic structure! / 構造, single chain That it is a shape structure!

This includes (meth) acrylamide homopolymers as well as copolymers containing (meth) acrylamide in the main chain. Comonomers in this case include unsaturated acids such as acrylic acid or methacrylic acid (hereinafter collectively referred to as “(meth) acrylic acid”), maleic anhydride, maleic acid, fumaric acid, crotonic acid, itaconic acid, etc. Derivatives such as carboxylic acids and their salts; unsaturated sulfonic acids such as (meth) acrylamidoalkyl sulfonic acids and their salts; and the like. As the salt, monovalent metal salts such as lithium, sodium and potassium; ammonia salts; amine salts such as monoethanolamine, dipropanolamine and triethanolamine are preferable. In the case of a copolymer, the polymerization ratio (molar ratio) of (meth) acrylamide is preferably 0.5 or more, more preferably 0.8 or more.

[0087] The molecular weight (weight average molecular weight) of the linear structure type (meth) acrylamide water-soluble polymer is preferably 50,000 or more in order to obtain the effect of controlling the transfer amount of the low viscosity ink. It is more preferable that it is 10,000 or more. It is still more preferable that it is 1,000,000 or more. On the other hand, the upper limit of the molecular weight is not particularly limited, but is preferably about 15 million or less from the viewpoint of adjusting the blending amount which is preferably 30 million or less.

The linear structure type (meth) acrylamide water-soluble polymer is a polymer having a linear structure, and when dissolved in water, its molecular structural strength S leads to a high degree of freedom in the intramolecular bond angle. It shows unique behavior in water, such as high-molecular and three-dimensional entanglement caused by the structure.

[0088] The content of the spinnability-imparting agent as described above is preferably 0.01 to 5% by weight, and preferably 0.03 to 2% by weight, with respect to the total amount of force ink depending on the type. More preferred is 0.03 to 0.5% by weight, and even more preferred is 0.05 to 0.2% by weight. If the blending amount of the spinnability imparting agent is too large, the viscosity of the ink may increase and the dryness of the printed matter may deteriorate soon.

Since the ink thread length may increase or decrease under the influence of other ink components, it is preferable to adjust the type and content of the spinnability imparting agent as appropriate in consideration of the effects of other ink components. That's right.

[0089] It is preferable that the ink has spinnability. Specifically, the ink string length is 30 mm when a 15 mm diameter chrome steel ball is pulled up by 150 mmZs from ink at 23 ° C. More preferably, it is 40 mm or more, more preferably 50 mm or more. With such an ink having a long thread length, the amount of transfer to the printing paper is suppressed regardless of the viscosity of the ink, that is, even with a low viscosity ink as described above. As a result, the dryness of the printed matter is good, and a sharp and high-quality image can be obtained without blurring of fine characters and fine lines.

[0090] Specifically, the measurement of the kite length can be performed using a measuring instrument as shown in FIG. This measuring instrument includes a container 201 containing ink, a chromium steel ball 202 having a diameter of 15 mm, a stepping motor 203, and a benolet 204. The chrome maoka ball 202 is fixed to a belt 204 that is rotated by a stepping motor 203, and moves up and down at a constant speed. The measurement environment was 23 ° C, and the entire chromium steel ball 202 was immersed in the ink in the container 201 so that the top of the sphere coincided with the line of the ink level, and was pulled up at a speed of 150 mm per second. Take a picture of the situation with a camera (not shown) installed in front of the measuring instrument and record it, and the ink just before the ink thread formed between the ink level and the steel ball is torn off. The maximum length of the kite string (distance between the ink level and the steel ball bottom) should be read from the recorded image.

[0091] The upper limit of the yarn length is not particularly limited, but is preferably 500 mm or less, more preferably 250 mm or less, and even more preferably 200 mm or less. If the thread length exceeds 500 mm, the amount of ink transfer will be suppressed too much, and fine characters and fine lines may be partially lost.If the length exceeds 250 mm, the solid portion will be uneven if there is a solid portion. May occur. The reason for this is not clear, but when the stencil sheet and the printing paper are peeled off, the punching force of the stencil sheet is also transferred to the ink transferred to the printing paper. If the ink is attracted to each other, it is thought that unevenness occurs in the formed image.

[0092] An arbitrary thickener can be added to the ink as a viscosity modifier. For example, one or more of a water-soluble polymer thickener and a clay mineral thickener can be used. it can. As water-soluble polymer thickeners, natural polymers, semi-synthetic polymers, and synthetic polymers can be used.

Natural polymers include, for example, plant-based natural polymers such as gum arabic, carrageenan, guagam, locust bean gum, pectin, tragacanth gum, corn starch, konjac mannan, agar, etc .; An animal natural polymer such as gelatin, casein, or glue can be used.

Examples of the semi-synthetic polymer include cellulose semi-synthetic polymers such as ethyl cellulose, carboxymethyl cellulose, hydroxyethinoresenorerose, hydroxypropenoresenorelose, methinoresenorelose, and hydroxypropylmethylcellulose; Starch semi-synthetic polymers such as tert, sodium carboxymethyl starch and cyclodextrin; Alginate semi-synthetic polymers such as sodium alginate and propylene glycol alginate; sodium hyaluronate can be used.

[0093] Synthetic polymers include, for example, polyacrylic acid, polymethacrylic acid, polycrotonic acid, polyitaconic acid, polymaleic acid, polyfumaric acid, acrylic acid-methacrylic acid copolymer, acrylic acid-itaconic acid copolymer, acrylic Acid Maleic acid copolymer, Acrylic acid Acrylic amide copolymer, Acrylic acid Acrylic acid ester copolymer, Acrylic acid-methacrylic acid ester copolymer, Acrylic acid-sulfonic acid monomer copolymer, Acrylic acid-birylpyrrolidone Unsaturated carboxylic acid-based synthetic polymers such as copolymers, maleic anhydride alkyl butyl ether copolymers, etc .; such as polybulur pyrrolidone, polybutyl alcohol, polybutyl methyl ether, poly N-bulucaceamide, polyacrylamide, etc. Bull synthetic polymer: Polyethylene oxide Polyethylene I Min, can be used a polyurethane

[0094] Among these thickeners, unsaturated carboxylic acid-based water-soluble polymer thickeners, which are electrolyte-type thickeners having a large number of dissociating groups in the side chain, have a desired thickening effect even in a small amount. Is obtained It is preferably used. Here, as the unsaturated carboxylic acid-based synthetic polymer, as illustrated above, for example, acrylic acid, methacrylic acid, maleic anhydride, maleic acid, fumaric acid, crotonic acid, and itaconic acid group power are selected 1 Examples thereof include water-soluble polymers containing at least one kind of unsaturated carboxylic acid in the main chain, and these neutralized salts are included in the category only of the above-mentioned unneutralized type. Examples of the neutralized salt include alkali metal salts such as sodium and potassium, ammonium salts and alkanolamine salts such as triethanolamine, and specific examples include sodium polyacrylate and polyacrylic acid. Potassium, ammonium polyacrylate, triethanolamine polyacrylate, sodium polymethacrylate, polymethacrylate, sodium polyitaconate, sodium polymaleate, sodium acrylate-methacrylic acid copolymer, acrylic acid Maleic acid copolymer sodium and the like can be preferably used.

[0095] As the clay mineral-based thickener, for example, smectite-based clay minerals such as montmorillonite, hectorite, and savonite can be used.

In addition to the ink thickener, the water-soluble polymer exemplified as the thickener can be used as a colorant fixing agent for printing paper, depending on the type and amount thereof. Further, when a pigment is used as the colorant, it can also be used as a pigment dispersant.

[0096] In addition to the above components, the ink may optionally contain a pigment dispersant, a fixing agent, an antifoaming agent, a surface tension reducing agent, a pH adjuster, an antioxidant, an antiseptic, and the like. .

The ink can contain an alkali-soluble resin and can be used as a fixing agent for a colorant on a printing material such as printing paper. When a pigment is used as the colorant, alkali-soluble resin can also be used as a pigment dispersant. Alkali-soluble rosin means a polymer that is insoluble in water but becomes water-soluble in the presence of alkali. Therefore, even if the compound name is the same, for example, acrylic acid-acrylic acid ester copolymer, in the present invention, it is classified into a water-soluble polymer or an alkali-soluble resin depending on its solubility.

Examples of the alkali-soluble resin include styrene- (meth) acrylic acid copolymer, styrene α-methylstyrene (meth) acrylic acid copolymer, and styrene (meth) acrylic acid. Steru (meth) acrylic acid copolymer, styrene maleic anhydride copolymer, vinyl naphthalene (meth) acrylic acid copolymer, vinyl naphthalene maleic acid copolymer, isobutylene maleic anhydride copolymer, (meth) acrylic Acid ester (meth) acrylic acid copolymer, acrylic acid ester-methacrylic acid ester (meth) acrylic acid copolymer can be used. These can be used alone or in combination of two or more. These alkali-soluble resins are neutralized with any alkali such as alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkanolamines such as aqueous ammonia and triethanolamine, and water. It can be used after being soluble.

If a large amount of alkali-soluble resin is contained, the printing performance after the printer is not used may be hindered. Therefore, it is preferable to contain the alkali-soluble resin in the ink in a range of 5% by weight or less in terms of solid content. More preferably, it is 3% by weight or less.

[0098] An oil-in-water (OZW) type rosin emulsion can be included in the ink and used as a fixing agent for a colorant on a printing medium such as printing paper. In the case where a pigment is used as the colorant, this rosin emulsion can also be used as a pigment dispersant.

Examples of oil-in-water (OZW) rosin emulsions include poly (vinyl acetate), ethylene / vinyl acetate copolymer, vinyl acetate / acrylic acid ester copolymer, polyacrylic acid ester, polymethacrylic acid ester, polystyrene, styrene acrylic acid. Emulsions such as ester copolymers, styrene butadiene copolymers, salt vinylidene acrylate copolymers, polychlorinated bulls, salt bully acetate bur copolymers, polyurethanes, etc. can be used. . You can use two or more of these together!

When containing a large amount of rosin emulsion, there is a risk of affecting the printing performance of the printing press after it is not used, so it is preferable to add it in the ink in a range of 5% by weight or less in terms of solid content. Preferably it is 2 weight% or less.

[0099] In order to improve the image quality of printed matter, extender pigments can be included in the ink.

Examples of extender pigments that can be used include clay, talc, clay, diatomaceous earth, calcium carbonate, potassium carbonate, barium sulfate, alumina white, silica, kaolin, my strength, and aluminum hydroxide. You can use more than one species together.

If the extender pigment is contained in a large amount, it may hinder the fixing of the colorant to the print medium, Since the printing performance after the printer is not used may be hindered, the content is preferably 5% by weight or less, more preferably 2% by weight or less.

[0100] Further, as a pigment dispersant, an antifoaming agent, a surface tension reducing agent, etc., an anionic surfactant, a force thione surfactant, an amphoteric surfactant, a nonionic surfactant, or a polymer system, a silicone system A fluorine-based surfactant can be contained in the ink.

In order to adjust the viscosity and pH of the ink, an electrolyte can be added to the ink. Examples of the electrolyte include sodium sulfate, potassium hydrogen phosphate, sodium citrate, potassium tartrate, and sodium borate. Two or more kinds may be used in combination. Sulfuric acid, nitric acid, acetic acid, sodium hydroxide, potassium Mizusani匕, Mizusani匕ammonium - © beam, also triethanolamine, can be used as NebaSuke agent or _P H modifiers increase of the ink.

[0101] By blending an antioxidant, it is possible to prevent oxidation of the ink components and improve the storage stability of the ink. Examples of the anti-oxidation agent that can be used include L-ascorbic acid, L-sodium ascorbate, sodium isoscorbate, potassium sulfite, sodium sulfite, sodium thiosulfate, sodium nithionite, and sodium pyrosulfite.

By adding preservatives, it is possible to prevent ink decay and improve storage stability. Examples of preservatives include isothiazolones such as 5 chloro-2-methyl-4 isothiazoline-3-one, 2-methyl-4 isothiazoline-3 on, 2-n-octyl-4 isothiazoline 3 on, 1,2 benzoisothiazoline 3 on. Hexahydro 1, 3, 5 Tris (2 hydroxyethyl) s Triazine preservatives such as triazine; 2 Pyridine quinoline preservatives such as sodium pyridinethiol 1-oxide and 8-oxyquinoline; Dimethyldi Dithiocarbamate preservatives such as sodium thiocarbamate; 2, 2 dibromo-3 -tri-propionamide, 2 bromo 2-toro 1, 3 propanediol, 2, 2 dibu-moe 2 ditroethanol , 2 Jib mouth mo 2 Organic bromine preservatives such as 2, 4-disianobutane; methyl p-hydroxybenzoate, p-hydroxy Echiru benzoate, potassium sorbate, sodium dehydroacetate, that are use salicylic acid leaves in.

[0102] The ink is prepared by mixing water, a colorant, and the above-mentioned components appropriately blended as necessary. The details thereof are not particularly limited. For example, a part of water, a pigment, and a pigment dispersant are mixed, and the pigment is dispersed using a dispersing means such as a ball mill or a bead mill, while the remaining water, a spinnability imparting agent, and a water-soluble organic substance are dispersed. Mix the solvent and mix them together.

[0103] The stencil sheet used in the present invention can be produced by a conventionally known method. Specifically, a method of laminating a porous support and a thermoplastic resin film with an adhesive as disclosed in JP-A-11-309954; disclosed in JP-A-2001-10247, etc. A method of thermally bonding a porous support and a thermoplastic resin film without using an adhesive; disclosed in JP-A-10-147075, etc., on one surface of a thermoplastic resin film A method for forming a porous resin film and further laminating a porous fiber film on the surface thereof; a method for forming a porous resin film on a porous support disclosed in JP-A-2003-165282 And the like.

Example

[0104] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. Hereinafter, “% by weight” is simply referred to as “%”.

(Examples 1 to 11, Comparative Examples 1 to 6)

Inks A to D were prepared as follows according to the formulation shown in Table 1.

(Ink A)

While slowly stirring distilled water 29.97%, this is a linear structure type sodium polyacrylate (Nippon Pure Chemicals Co., Ltd. “Alonbis S”, molecular weight 4 million to 5 million). 03% was slowly added to dissolve. The resulting linear-structure-type sodium polyacrylate aqueous solution 30.0% was used as a colorant, and self-dispersing carbon black dispersion “Bonjet Black CW-1” (pigment content 20%) manufactured by Orient Chemical Industry Co., Ltd. Ink A was obtained by mixing 50.0% and 20.0% polyethylene glycol (“polyethylene glycol 20 0” manufactured by Wako Pure Chemical Industries, Ltd.) as a water-soluble organic solvent.

[0105] (Ink B)

While slowly stirring distilled water 29.42%, the same linear structure type sodium polyacrylate as in ink A 0.03%, and carboxymethylcellulose sodium as a thickener (55% by Kanto Chemical Co., Ltd.) was slowly added and dissolved. Ink B was obtained by mixing 30.0% of the obtained linear structure type sodium polyacrylate aqueous solution with a colorant and a water-soluble organic solvent in the same manner as ink A.

(Ink C, D)

Inks C and D were obtained in the same manner as ink B except that the formulation shown in Table 1 was used.

[0106] The viscosity of each ink obtained (ink viscosity at lOPa when the shear stress was increased from OPa at a rate of 0.1 lPaZs at 23 ° C) was determined by the Haake stress controlled rheometer R S75 (cone angle). 1 °, diameter 60 mm).

[0107] The string length of each ink obtained was measured using a measuring instrument as schematically shown in FIG. That is, under an ambient temperature of 23 ° C, the container 201 is filled with ink, and the entire chrome steel ball 202 (diameter 15 mm) is filled in the container 201 so that the upper part of the sphere coincides with the ink level line. Then, when the chrome steel ball was pulled up vertically at a speed of 150 mm per second, it was viewed in front using a camera (3CCD color video camera module XC-003 manufactured by Sony Corporation) (not shown). Take a photo and read from the recorded image the maximum length of the ink fountain just before the ink fountain formed between the ink surface and the steel ball is broken (distance between the ink surface and the bottom of the steel ball). I got it.

[0108] [Table 1]

Using the above ink, the stencil printing machine shown in Fig. 17 (prototype manufactured by Riso Kagaku Co., Ltd.), as shown in Table 2 and Table 3, the pressing force (A) by the press roll and the peripheral speed of the drum ( B), ink viscosity (C), and stencil sheet thickness (D) were changed, and printing was carried out on printing paper (“Ideal Paper Thin Edge” manufactured by Riso Kagaku Kogyo Co., Ltd.).

The stencil paper was made by bonding a thermoplastic resin film and a porous support with an adhesive. The biaxially stretched polyester film with a thickness of 2 m is used for the thermoplastic resin film, and the thin paper mixed with 30% natural fiber and 70% synthetic fiber is used for the porous support. did. The thickness of the stencil paper was adjusted by changing the basis weight of the thin paper.

[0110] The pressing force (A) by the press roll was measured by measuring the force applied to the drum by the press roll, and the unit was N. Specifically, while the press roll was being pressed by the drive unit, the total load that the entire press roll pressed against the drum was measured with a load cell to determine the pressing force.

[0111] As for the peripheral speed (B) of the drum, the rotational speed of the drum and the peripheral force of the drum were also obtained. The rotation speed of the drum was measured with a rotary encoder, and the rotation Zmin was used as a unit. When the drum circumference is 0.5 m and the rotation speed is 60 rotations Zmin, the peripheral speed is 0.5 (m) X 60 (rotation Zmin in) / 60 (s / min) = 0.5 (mZs) It becomes. Similarly, when the rotation speed is 100 rotations Zmin and 150 rotations Zmin, the peripheral speeds are 0.83 (m / s) and 1.25 (mZs), respectively.

[0112] Thickness of stencil sheet (D) is the thickness of 10 sheets of stencil sheet, using a straight tooth thickness micrometer 369-511PDM-25DM (14.3 mm in diameter) manufactured by Mitutoyo Corporation. The thickness per sheet was measured and calculated. The measurement place was changed five times, and the average value of the five times was taken as the thickness of the stencil paper.

[0113] In each of the examples and comparative examples, the image quality (image defects, point-like stains) of the printed matter obtained was visually evaluated. The missing images were designated as A when the images were printed without missing images, and D when the images were missing. For the spot-like stains, A was given when there was no stain, B was given when there was a little stain, and D was given when the stain was severe.

The obtained results are also shown in Table 2 and Table 3.

[0114] [Table 2]

Table 2

Table 3

As shown in the above table, in the printing of Examples satisfying the formula (1), it was possible to obtain a good printed matter in which no image chipping or dot-like stains occurred.

Claims

Claims [1] A drum on which the stencil paper is mounted on the surface of its outer peripheral wall and is rotatable, and has an ink supply section at a position upstream of printing from the maximum printing area of the outer peripheral wall of the drum. Using a stencil printing machine equipped with an ink supply means for supplying ink to the surface of the outer peripheral wall from the section and a press roll for pressing the fed printing medium against the outer peripheral wall, a pre-made stencil sheet is mounted A stencil printing method in which ink is passed from a perforated portion of a stencil sheet that has been pre-made to transfer it to a printing medium by pressing the drum that has been rotated with a press roll, the pressing force of the press roll (A: N) , Printing so that the relationship between the peripheral speed of the drum (B: m / s), the viscosity of the ink (C: mPa · s), and the thickness of the stencil sheet (D: m) satisfies the following formula (1): Stencil printing method to be performed.

(Number 1)

130≤ ^ (B / A) X (C + 200) X ^ D≤400 (1)

[2] The stencil printing method according to claim 1, wherein the range of the formula (1) is 160≤ ^ (BZA) X (C + 200) 0≤330.

3. The stencil printing method according to claim 1 or 2, wherein a water-based ink is used as the ink.

4. The stencil printing method according to claim 3, wherein the water-based ink has an ink viscosity at lOPa of not more than 500 mPa's when the shear stress is increased from OPa at a speed of 0.1 PaZs at 23 ° C. .

5. The stencil printing method according to claim 3, wherein the water-based ink has an ink thread length of 30 mm or more when a chromium steel ball having a diameter of 15 mm is pulled up from the ink at 23 ° C. at 150 mm / s. .