JP4777551B2 - Plate making apparatus and stencil printing apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plate making device and the stencil printing equipment.
[0002]
[Prior art]
Conventionally, digital thermal stencil printing is known as a simple printing method. This is based on the reading information of the original image, and a thermal head stencil master (hereinafter also simply referred to as “master”) as a printing plate is melted and perforated by a thermal head or the like, and the master made from the plate is printed in a porous cylindrical shape. Printing is performed by winding the drum on the outer peripheral surface.
Ink is supplied to the inner surface of the drum by the ink supply means provided inside the printing drum, and the printing paper is pressed against the printing drum by pressing means such as a press roller, so that the ink oozes out from the perforated portion of the master and printing paper. As a result, an ink image is formed on the printing paper.
[0003]
The master has a structure in which a porous fiber film as an ink-permeable support is bonded to a thermoplastic resin film (hereinafter also simply referred to as “film”) with an adhesive (hereinafter referred to as “ordinary master”). It has been known. As the porous fiber membrane, generally, hemp fiber or a mixture of hemp fiber and synthetic fiber and wood fiber is used.
However, in such a configuration, since there is a support made of fibers immediately above the film, a large amount of adhesive accumulates in the portion where the fibers overlap and the film are in contact with each other in the form of a web of water. There was a problem that printing was uneven due to difficulty in perforation by the thermal head.
[0004]
In order to cope with such a problem, Japanese Patent Application Laid-Open No. 10-236011 discloses that a porous resin film made of a resin is laminated on one surface of a thermoplastic resin film and bonded to each other on the porous resin film. There has been proposed a heat-sensitive stencil master in which a porous fiber film made of a fibrous material is laminated.
The porous resin film means a porous film formed by precipitation of a resin dissolved in a solvent and condensation. The porous resin film has a structure in which fine voids are complicatedly overlapped in the thickness direction.
Porous fiber membranes are made of thin paper made of fiber materials such as cotton, hemp and other plant fibers, polyester, polyvinyl alcohol and other synthetic materials. The fiber materials are bonded together and entangled or knitted. It means a membrane that is bonded.
According to the heat-sensitive stencil master having such a configuration, it is possible to solve the problems such as the printing unevenness and the like, to improve the stiffness and tensile strength of the master, and to improve the image quality.
[0005]
[Problems to be solved by the invention]
When using the above-mentioned master having a porous resin film as a printing plate, due to its unique structure, plate making conditions (such as perforation energy conditions) and printing conditions (differences in the ease of ink passage) are compared to using a normal master. The ink type, etc.) varies greatly.
For this reason, in a stencil printing apparatus in which conditions are set corresponding to a master having a porous resin film, if printing is performed by setting a master in which a porous fiber film is laminated on a film, printing failure occurs. Conversely, if printing is performed with a master having a porous resin film set in a stencil printing apparatus in which conditions are set corresponding to a normal master, printing failure occurs.
It is difficult for the operator to identify the master type visually. If there is a set mistake, the problem is known after printing at least the first page, and it is necessary to discard the master that has been made, replace the master, or reset the master. Wasteful consumption and large downtime.
[0006]
In addition, even a master having the same porous resin film has a problem in that the porosity varies depending on the production lot, and the ink passing property is different so that a stable print quality cannot be obtained.
[0007]
The present invention, plate-making can be obtained a stable print quality even if there are variations in the porosity of the multi-porous resin membrane device, to provide stencil printing equipment having a plate making apparatus, and an object .
[0008]
[Means for Solving the Problems]
In order to achieve the above object, in the invention described in claim 1, plate making means for perforating a master having a support on one surface of a thermoplastic resin film based on image information, and one surface side of the master and a light reflective sensing means provided on the low reflectance member provided opposite to the light reflective sensing means on the other surface side of the master, based on the detection information of the light reflective detector It has a control means for identifying the gap state of the master support, and the control means changes the plate making conditions based on the gap state identification.
[0009]
In the invention according to claim 2, in the stencil printing apparatus for performing printing by making a master by a plate making apparatus based on image information and winding the master having been made on the outer peripheral surface of a printing drum, the plate making apparatus comprises: The configuration of claim 1 is adopted.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment of the present invention will be described as a reference example with reference to the drawings.
First, based on FIG. 1, the overall configuration of the stencil printing apparatus and the outline of the stencil printing process in this embodiment will be described.
An original reading unit 80 is provided at the upper part of the apparatus main body 50, and a printing drum unit 100 having a porous printing drum 101 is provided at a lower central part thereof. A plate making apparatus 90 is provided on the upper right side of the printing drum unit 100, and a plate discharging unit 70 is provided on the upper left side of the printing drum unit 100. Further, a sheet feeding unit 110 is provided below the plate making apparatus 90, a printing pressure unit 120 is provided below the printing drum unit 100, and a paper discharge unit 130 is provided below the plate discharging unit 70.
[0018]
Next, the printing operation of the stencil printing apparatus according to the above configuration will be described.
First, a document 60 having an image to be printed is placed on a document placing table (not shown) arranged at the top of the document reading unit 80, and a plate making start key on an operation panel (not shown) is pressed. Along with the pressing of the plate making start key, a plate removing process is first executed. That is, in this state, the used heat-sensitive stencil master 61b used in the previous printing remains attached to the outer peripheral surface of the printing drum 101 of the printing drum unit 100.
[0019]
When the printing drum 101 rotates counterclockwise and the rear end portion of the used heat-sensitive stencil master 61b on the outer peripheral surface of the printing drum 101 approaches the plate release roller pair 71a, 71b, the plate release roller pair 71a, 71b is While rotating, the rear end portion of the used heat-sensitive stencil master 61b is scooped up by the one pair of plate release roller 71a.
The used heat-sensitive stencil master 61b is composed of a discharge plate conveying belt pair 72a wound around a discharge plate roller pair 73a, 73b disposed on the left side of the discharge plate peeling roller pair 71a, 71b and the discharge plate peeling roller pair 71a, 71b. , 72b and discharged into the plate discharge box 74 while being conveyed in the direction of the arrow Y1, and is peeled off from the outer peripheral surface of the printing drum 101 to complete the plate discharge process. At this time, the printing drum 101 continues to rotate counterclockwise. The used heat-sensitive stencil master 61 b that has been peeled and discharged is then compressed inside the discharge box 74 by the compression plate 75.
[0020]
In parallel with the plate removal process, the document reading unit 80 reads the document. That is, the document 60 placed on a document placing table (not shown) is transported in the directions of the arrows Y2 to Y3 by the rotation of the separation roller 81, the pair of front document transport rollers 82a and 82b, and the pair of rear document transport rollers 83a and 83b. It is used for exposure reading. At this time, when there are a large number of originals 60, only the lowermost original is conveyed by the action of the separating blade 84. In reading the image of the document 60, the reflected light from the surface of the document 60 illuminated by the fluorescent lamp 86 while being conveyed on the contact glass is reflected by the mirror 87, and the image formed of a CCD (charge coupled device) through the lens 88. This is done by entering the sensor 89.
That is, the original 60 is read by a well-known reduction-type original reading method, and the original 60 from which the image has been read is discharged onto the original tray 80A. The electrical signal photoelectrically converted by the image sensor 89 is input to an analog / digital (A / D) conversion board (not shown) in the apparatus main body 50 and converted into a digital image signal.
[0021]
On the other hand, in parallel with this image reading operation, plate making and plate feeding processes are performed based on the digital signalized image information. That is, the roll-shaped heat-sensitive stencil master 61 set at a predetermined portion of the plate-making apparatus 90 is pulled out of the roll state and pressed against the thermal head 91 via the heat-sensitive stencil master 61, and the tension. The pair of rollers 93a and 93b are transported to the downstream side of the transport path.
For the heat-sensitive stencil master 61 transported in this way, a plurality of minute heat generating portions arranged in a line on the thermal head 91 correspond to a digital image signal sent from an A / D conversion board (not shown). The thermoplastic resin film (described later) of the heat-sensitive stencil master 61 that generates heat selectively and is in contact with the generated heat generating portion is melt-pierced. In this way, image information is written as a perforation pattern by position-selective melt perforation of the heat-sensitive stencil master 61 according to the image information.
On the upstream side of the thermal head 91 in the conveying direction of the heat-sensitive stencil master 61, a light-transmitting detection means 20 for detecting the light transmittance (for example, light transmission amount) of the heat-sensitive stencil master 61 is provided.
[0022]
As shown in FIG. 1, the front end of the prepressed heat-sensitive stencil master 61a on which image information is written is sent out toward the outer peripheral side of the printing drum 101 by a pair of plate-feeding rollers 94a and 94b, and is guided by a guide member (not shown). The advancing direction is changed downward, and hangs down toward the master clamper 102 (indicated by the phantom line) in which the printing drum 101 in the illustrated plate feeding position state is expanded. At this time, the used heat-sensitive stencil master 61b has already been removed from the printing drum 101 by the plate discharging process.
[0023]
Then, when the leading end of the plate-making heat-sensitive stencil master 61a is clamped by the master clamper 102 at a fixed timing, the printing drum 101 rotates on the outer peripheral surface while rotating in the direction A (clockwise direction) in the figure. The stencil master 61a is gradually wound. The rear end portion of the prepressed heat-sensitive stencil master 61a is cut into a fixed length by a cutter 95.
[0024]
When one plate-made heat-sensitive stencil master 61a is wound around the outer peripheral surface of the printing drum 101, the plate-making and plate-feeding steps are finished, and the printing step is started. First, the uppermost one of the printing papers 62 stacked on the paper feed tray 51 is sent in the direction of arrow Y4 toward the feed roller pair 113a, 113b by the paper feed roller 111 and the separation roller pair 112a, 112b. Further, the feed roller pair 113a, 113b is sent to the printing pressure unit 120 at a predetermined timing synchronized with the rotation of the drum unit 100. When the fed printing paper 62 comes between the printing drum 101 and the press roller 103, the press roller 103 that has been separated below the outer peripheral surface of the printing drum 101 is moved upward, whereby the printing drum 101. It is pressed by the pre-pressed heat-sensitive stencil master 61a wound around the outer peripheral surface. In this way, ink oozes out from the perforated portion of the printing drum 101 and the perforated pattern portion (not shown) of the pre-printed heat-sensitive stencil master 61a, and the oozed ink is transferred to the surface of the printing paper 62 to produce a printed image. Is formed.
[0025]
At this time, on the inner peripheral side of the printing drum 101, ink is supplied from the ink supply pipe 104 to the ink reservoir 107 formed between the ink roller 105 and the doctor roller 106, and is in the same direction as the rotation direction of the printing drum 101. Ink is supplied to the inner peripheral side of the printing drum 101 by the ink roller 105 that is in contact with the inner peripheral surface while rotating in synchronization with the rotation speed of the printing drum 101.
[0026]
The printing paper 62 on which the printing image is formed in the printing pressure unit 120 is peeled off from the printing drum 101 by the paper discharge peeling claw 114 and is sucked by the suction fan 118, while the suction paper discharge inlet roller 115 and the suction paper discharge outlet roller. By the rotation of the conveyor belt 117 stretched around 116 in the counterclockwise direction, the conveyor belt 117 is conveyed toward the sheet discharge unit 130 as indicated by an arrow Y5 and sequentially discharged and stacked on the sheet discharge table 52. In this way, so-called trial printing is completed.
[0027]
Next, when the number of prints is set with a numeric keypad (not shown) and a print start key (not shown) is pressed, the steps of paper feeding, printing and paper discharge are repeated for the set number of prints in the same process as the trial printing. All the processes of stencil printing are completed.
[0028]
As shown in FIG. 2, the light transmission detecting means 20 includes a transmission type photosensor 20a as a light receiving means and a light emitting means 20b such as an LED, which are opposed to each other with a heat sensitive stencil master 61 interposed therebetween. It is provided as follows.
As shown in FIG. 3, the detection signal from the transmissive photosensor 20 a is input to the control means (main controller of the stencil printing apparatus) 200. The control means 200 controls the driving of the thermal head 91 based on the detection signal from the transmissive photosensor 20a. The control means 200 is a microcomputer including a CPU, ROM, RAM, I / O interface and the like.
[0029]
As shown in FIG. 4, the heat-sensitive stencil master 61 has a porous resin film 206 made of a thermoplastic resin on a thermoplastic resin film 204 (one surface side) and a porous material made of a fibrous material bonded to each other. A porous fiber membrane 208 as a membrane is laminated.
The porous resin film 206 includes a resin film component 206a and a gap 206b.
The porous resin film 206 is formed by precipitating and condensing a resin dissolved in a solvent, and has a structure having a large number of voids 206b inside and on the surface of the film.
From the viewpoint of ink permeability, it is desirable that the gap 206b is continuous in the thickness direction in the film, and the gap 206b penetrates in the ceiling direction when the thermoplastic resin film 204 is a floor.
[0030]
As the resin as the main component of the porous resin film 206, polyethylene, polypropylene, polybutene, styrene resin, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, vinyl chloride- Vinyl-based resins such as vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, styrene-acrylonitrile copolymer, polyacrylonitrile, polyacrylic plastic, diene plastic, polybutylene, polyamide such as nylon, polyester , Polyphenylene oxide, (meth) acrylic acid ester, polycarbonate, polyacetal, fluorine resin, polyurethane plastic, various natural plastics Stick, natural rubber-based plastic, various thermoplastic elastomers, acetyl cellulose, acetyl butyl cellulose, cellulose derivatives such as acetyl cellulose, etc. and microorganisms plastics, such as copolymers containing these polymers. In addition, various carbohydrates such as various fatty acids and waxes, and various proteins can also be used.
[0031]
A filler may be added to the resin solution in the manufacturing process of the porous resin film 206 as necessary. This addition affects the shape, strength, and pore size of the porous resin film produced during the drying process. Specific examples include inorganic compounds such as zinc oxide, titanium dioxide, calcium carbide, and silica, and organic polymer particles such as polyvinyl acetate, polyvinyl chloride, and polymethyl acrylate. Microcapsules and Matsumoto Microfire (Matsumoto Yushi Seiyaku Co., Ltd.) can also be used effectively.
Furthermore, an antistatic agent, an anti-stick agent, a surfactant, an antiseptic, an antifoaming agent, and the like can be used in combination with the porous resin film 206 as long as perforation is not inhibited.
[0032]
As the thermoplastic resin film 204, those conventionally used for heat-sensitive stencil masters such as vinyl chloride-vinylidene chloride copolymer film, polypropylene film, and polyester film can be used.
A stick prevention layer for preventing sticking with the thermal head 91 can be provided on the surface of the film. In this case, as the anti-stick agent used, those generally used in conventional heat-sensitive stencil masters for heat-sensitive stencil printing can be used. For example, silicone release agents, fluorine release agents, phosphate ester surfactants, and the like can be used.
[0033]
The porous fiber membrane 208 is manufactured by a known method. Examples of the porous fiber membrane 208 include mineral fibers such as glass, sepiolite and various metals, animal fibers such as wool and silk, plant fibers such as cotton and hemp, regenerated fibers such as sufu and rayon, polyester, polyvinyl alcohol, and acrylic. And synthetic paper, semi-synthetic fiber such as carbon fiber, and thin paper such as inorganic fiber having a whisker structure.
The porous membrane is meant to include fibers such as Japanese paper, porous sheets, mesh sheets and the like.
[0034]
The porous resin film 206 has a structure in which minute voids are complicatedly overlapped in the thickness direction, and the light transmission property is poor. For this reason, even if the porous fiber film 208 is observed from the porous resin film 206 side, the porous fiber film 208 is hardly visible. In the master having the porous resin film 206, the amount of transmitted light detected by the transmissive photosensor 20a is reduced.
Therefore, if the level of light transmission is detected and compared, the master having the porous resin film 206 can be clearly distinguished from the normal master that is not.
[0035]
The ROM of the control means 200 stores a detection level (a predetermined range including a detection error) of the transmitted light amount in the thickness direction of the heat-sensitive stencil master 61 obtained in advance by experiments or the like. Based on the detection level, the type of the master is identified based on the detection signal of the transmissive photosensor 20a.
When the amount of transmitted light detected by the transmissive photosensor 20a is small and within the detection level range, the control means 200 determines that the regular heat-sensitive stencil master 61 to be used is set. And the start of plate making is allowed.
[0036]
When the amount of transmitted light detected by the transmissive photosensor 20a is large and out of the above detection level range, the control means 200 determines that the master is a different type of master, and a platen roller drive motor (not shown) The driving of the thermal head 91 is stopped (stop of plate making) and a warning is given.
This warning is given, for example, by displaying a message “Master type is not appropriate” on the liquid crystal display unit of the operation panel 202. In response to this message, the operator replaces the master (master having the porous resin film 206) corresponding to the setting conditions of the stencil printing apparatus.
In the present embodiment, the control for stopping the plate making and the warning is performed at the same time. However, the plate making may be stopped only without stopping the warning. In the present embodiment, when another type of master is set, the plate making stop and warning are performed. However, plate making may be performed by changing the plate making energy condition.
[0037]
Next, a second embodiment will be described based on FIG. The same parts as those of the above-described embodiment are denoted by the same reference numerals, and the description on the configuration and the function already described is omitted unless particularly necessary. Only the main part will be described (the same applies to other embodiments below).
As described above, even a master having the same porous resin film may have a variation in porosity depending on the production lot, and may not have a stable print quality due to different ink permeability.
Since void formation occurs randomly in the manufacturing process, the void ratios are not all the same microscopically, but there are cases where variations in the void ratio to the extent that ink permeability is affected occur between production lots.
An object of the present embodiment is to make it possible to obtain stable print quality even when such a variation in porosity occurs.
[0038]
The ROM of the control means 200A in the present embodiment stores a relational data table between the detection level of the transmitted light amount in the thickness direction of the heat-sensitive stencil master 61 and the optimum plate-making energy (drilling energy) obtained in advance by experiments or the like. ing. The control means 200A selects the plate making energy corresponding to the amount of transmitted light detected by the transmissive photosensor 20a from the relation data table, and applies the plate making energy to the thermal head 91.
That is, when the gap is dense and the amount of transmitted light is small, the ink permeability is poor. Therefore, the plate making energy is increased to increase the film perforation diameter, and the amount of ink transferred from the master to the paper is increased. Conversely, when the gap is rough and the amount of transmitted light is large, ink permeability is good, so the plate making energy is reduced to reduce the film perforation diameter, and the amount of ink transferred from the master to the paper is reduced. In the relational data table, the range of the amount of transmitted light is divided into multiple stages, and the ink transfer amount can be finely adjusted.
[0039]
Next, a third embodiment will be described based on FIGS. 6 and 7.
As described above, the master having a porous support made of a porous resin film has a structure in which fine voids are complicatedly overlapped in the thickness direction, and has a poor light transmission property. It is difficult to see what is on the other side. In this embodiment, it is intended to identify the void state by utilizing such structural characteristics.
As shown in FIG. 6, a reflective photosensor 30 as a light reflectivity detecting means is provided on one surface side of the heat-sensitive stencil master 61, and a low reflectance is provided on the other surface side in an opposing position. A black plate 31 is provided as a member (a member having poor reflectance).
[0040]
When the porous resin film is provided and the voids are dense, the light passing through the reflective photosensor 30 is poorly transmitted and the proportion absorbed by the black plate 31 is small, so that the amount of reflected light increases. On the other hand, when the gap is rough, the light emitted from the reflective photosensor 30 is easily transmitted, and the ratio of light absorbed by the black plate 31 is large.
The ROM of the control means 200B shown in FIG. 7 stores the detection level (predetermined range including detection error) of the reflected light amount in the thickness direction of the heat-sensitive stencil master 61 obtained in advance by experiments or the like. 200B identifies the type of master based on the detection signal of the reflective photosensor 30 with the detection level as a reference.
When the amount of reflected light detected by the reflective photosensor 30 is large and within the range of the detection level, the control means 200B determines that the regular heat-sensitive stencil master 61 to be used is set. And the start of plate making is allowed.
[0041]
When the amount of reflected light detected by the reflective photosensor 30 is small and outside the detection level range, the control unit 200B determines that the master is a different type of master, and a platen roller drive motor (not shown) The driving of the thermal head 91 is stopped (stop of plate making) and a warning is given.
This warning is given, for example, by displaying a message “Master type is not appropriate” on the liquid crystal display unit of the operation panel 202. In response to this message, the operator replaces the master (master having the porous resin film 206) corresponding to the setting conditions of the stencil printing apparatus.
In the present embodiment, the control for stopping the plate making and the warning is performed at the same time. However, the plate making may be stopped only without stopping the warning. In the present embodiment, when another type of master is set, the plate making stop and warning are performed. However, plate making may be performed by changing the plate making energy condition.
[0042]
Next, a fourth embodiment will be described based on FIG.
An object of the present embodiment is to make it possible to obtain stable printing quality even if the porosity varies between the same heat-sensitive stencil masters 61.
As shown in FIG. 8, the ROM of the control means 200C stores a relational data table between the detection level of the reflected light amount in the thickness direction of the heat-sensitive stencil master 61 and the optimum plate-making energy obtained in advance by experiments or the like. Yes. The control means 200 </ b> C selects plate making energy corresponding to the amount of reflected light detected by the reflective photosensor 30 from the relation data table, and applies the plate making energy to the thermal head 91.
That is, when the gaps are dense and the amount of reflected light is large, the ink permeability is poor. Therefore, the plate making energy is increased to increase the film perforation diameter, and the amount of ink transferred from the master to the paper is increased. On the contrary, when the gap is rough and the amount of reflected light is small, ink permeability is good. Therefore, the plate making energy is reduced to reduce the film perforation diameter, and the amount of ink transferred from the master to the paper is reduced. In the relational data table, the range of the amount of reflected light is divided into multiple stages so that the ink transfer amount can be finely adjusted.
[0043]
【The invention's effect】
According to the present invention, even if there is variation in the porosity between manufacturing lots can be obtained a stable print quality (image quality).
[Brief description of the drawings]
FIG. 1 is a schematic front view of a stencil printing apparatus according to an embodiment of the present invention.
FIG. 2 is an enlarged view of a main part of the plate making apparatus.
FIG. 3 is a control block diagram.
FIG. 4 is a schematic cross-sectional view showing the relationship between the heat-sensitive stencil master and the light transmission detecting means.
FIG. 5 is a control block diagram in the second embodiment.
FIG. 6 is an enlarged view of a main part of a plate making apparatus according to a third embodiment.
FIG. 7 is a control block diagram according to a third embodiment.
FIG. 8 is a control block diagram according to a fourth embodiment.
[Explanation of symbols]
20a Transmission type photo sensor 30 as light transmission detection means 30 Reflection type photo sensor 31 as light reflection detection means Black plate 90 as low reflectance member Plate making apparatus 200, 200A, 200B, 200C Control means 204 Thermoplastic resin film 206 Porous resin membrane

Claims (2)

Plate making means for perforating a master having a support on one side of the thermoplastic resin film based on image information, light reflectivity detecting means provided on one side of the master , and the other of the master A low-reflectivity member provided on the surface side facing the light-reflectivity detecting means , and a control means for identifying the gap state of the support of the master based on the detection information of the light-reflectivity detecting means. The control means changes the plate making conditions based on the identification of the gap state. In a stencil printing apparatus that performs printing by making a master by a plate making apparatus based on image information, and winding the pre-made master around the outer peripheral surface of a printing drum,
2. The stencil printing apparatus according to claim 1 , wherein the stencil printing apparatus is the one described in claim 1 .

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