JP2000141595A - Printing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multicolor printing apparatus being easily operable and of low cost and having a small-sized and compact structure. SOLUTION: This printing apparatus is equipped with printing plate drums 1A holding and retaining plates, thermal water-repellent printing plates 1B held and retained by the plate drums 1A, writing devices 2 writing data to be printed on the plates, on the plate drums 1A, developers 3 supplying ink to the plates on the plate drums 1A, a transfer device 4 having a transfer body 4-1 which receives, through transfer, the ink supplied to the plates on the plate drums 1A, a transfer roller device 5 which transfers the ink transferred onto the transfer body 4-1 onto printing paper S, a printing paper supply device 7 which supplies the printing paper S to the transfer roller device 5, a cleaning device 6 which cleans the transfer body 4-1 after completion of printing, etc., as basic components. In this case, the transfer body 4-1 of the transfer device 4 is constituted of a transfer belt. In the transfer device 4, besides, the transfer belt receives the ink in a plurality of kinds to be used for printing from the plate drums and the ink in a plurality of kinds is transferred at once onto the printing paper S.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus generally used in the field of printing machines such as offset printing machines and stencil printing machines, and more particularly, to a commercial printing field represented by offset printing, DTP, and the like. The present invention relates to a printing apparatus applied in fields such as short-run printing and OA equipment printing, and more particularly to a printing apparatus that uses a heat-sensitive and water-repellent printing plate and performs multicolor printing using a transfer device.

[0002]

2. Description of the Related Art Offset printing machines and stencil printing machines are known as conventional printing apparatuses, and are widely used in the field of commercial printing and the like. 2. Description of the Related Art In a printing machine in a full-scale printing field represented by an offset printing machine, a printing operator generally requires a dedicated operator who is called a skilled craftsman.
This is because skill is required in setting the printing plate, preparing and supplying the printing ink, replenishing the printing paper, and preparing the color matching for multi-color printing, and cleaning the printing press after printing. This is because it takes time.

[0003] Furthermore, printing machines are very expensive, ranging from several millions to tens of millions of yen, and can only be purchased at printing shops and the like. Among the consumables, PS plates are the most popular and widely used printing plates, and the number of printings that can be performed is tens of thousands. If it is not a copy unit, the printing cost cannot be paid. Furthermore, multi-color offset printing presses generally require a very large and large installation space, and can only be installed in a large room such as a printing shop or in a factory. In addition, there are so-called odors such as smell of printing ink, odor of volatile solvent for handling and cleaning, and so on.
Work environment such as K (tight, dirty, smell, etc.) has been a problem for many years.

On the other hand, stencil printing machines can be printed by simple operations and are inexpensive (price of printing machines is millions, but stencils, which are consumables, are very low-priced). However, the stencil printing machine cannot perform full-color printing, and the printing quality of one-color single-color printing is lower than that of offset printing, and has not been able to meet the demands of a full-scale printing press.
At present, it is content for the A field (office machine field).

[0005] Further, a typical color printing machine using adhesive printing ink is provided with a plurality of printing units, and the printing units corresponding to each color ink individually form ink images of each color on a plate drum, In general, the ink from the drum is transferred to the body of an individual transfer blanket drum, and each color ink image on the transfer blanket drum is sequentially superimposed on a printing paper and transferred to print a color image. For this reason, a plurality of printing units having a plate drum and a transfer blanket drum are required (Y (yellow), M (magenta), C (cyan), B
(4 printing units are required for each color of k (black) ink), which causes an increase in the size and cost of the apparatus. Also, in the method of superimposing the ink images of the respective colors on the printing paper as described above, since the accuracy of the superposition of a plurality of colors depends on the conveyance accuracy of the printing paper and the expansion / contraction of the paper, the occurrence of color misregistration or the like may occur. Unstable to

[0006]

SUMMARY OF THE INVENTION The present invention relates to the performance of the offset printing press and the stencil printing press described above in the field of printing.
It aims to solve problems such as machine price and easy operability. More specifically, the present invention is provided to solve some of the problems that the conventional printing press described above has not been able to solve for many years, and utilizes a heat-sensitive water-repellent printing plate, It is intended to provide a printing apparatus which can exhibit the characteristics of the above to the maximum.

This heat-sensitive water-repellent printing plate is made of a material having water repellency, and has the property that the water repellency when heated is lost from the material and the property is reversed to the water repellency, that is, the property becomes hydrophilic. Writing can be easily performed by a writing device such as a thermal head. Also, since the heat-sensitive water-repellent printing plate is very cheap and comparable to the stencil,
The printing cost is low, and printing is possible from a small number of copies.

Accordingly, the present invention utilizes a heat-sensitive and water-repellent printing plate having the above characteristics, and is a simple and operable, low-cost, small-sized, compact printing apparatus capable of multicolor printing. It is intended to provide. Further, in the present invention, a plurality of types of inks formed on the printing plate (for example, process inks of each color for full color: Y (yellow), M (magenta), C (cyan),
Bk (black)) having a transfer device on which a color image is formed on the transfer member and transferring the adhesive ink image formed on the transfer member to printing paper at a time. It is an object of the present invention to reduce the machine price of a printing apparatus that performs color printing, to make the machine compact, and to improve the image quality by improving the accuracy with respect to color misregistration of a color image.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a printing apparatus using a heat-sensitive water-repellent printing plate, and a printing plate drum for storing and holding the plate; A heat-sensitive and water-repellent printing plate stored and held, a writing device for writing data to be printed on the plate on the plate drum, a developing device for supplying printing ink to the plate on the plate drum, and the plate drum A transfer device having a transfer body that receives and transfers the ink supplied to the upper plate,
The basic configuration includes a transfer roller device for transferring the ink transferred to the transfer body to printing paper, a printing paper supply device for supplying printing paper to the transfer roller device, and a cleaning device for cleaning the transfer body after printing is completed. The transfer member of the transfer device is formed of a belt-shaped member (hereinafter, referred to as a transfer belt), and the transfer device receives a plurality of types of ink used for printing from the plate drum on the transfer belt, Is characterized in that a method of transferring a plurality of types of ink at a time is adopted (claim 1).

[0010] The present invention further provides the above printing apparatus,
When transferring ink from a plate drum to a transfer belt of a transfer device and receiving the ink, an ink transfer method is used in which a plurality of inks are transferred from a low-density ink and then sequentially transferred to a dark-density ink. (Claim 2).

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram of a printing apparatus showing an embodiment of the present invention, and shows an example of a full-color printing apparatus using a heat-sensitive and water-repellent printing plate. This printing apparatus includes a plurality of plate drum devices 1 each including a printing plate drum 1A for storing and holding a plate and a thermosensitive water-repellent printing plate 1B stored and held in the plate drum 1A.
A writing device 2 for writing data to be printed on a plate on each plate drum 1A, a developing device 3 for supplying printing ink to a plate 1B on each plate drum 1A, and a plate 1 on each plate drum 1A.
A transfer device (transfer belt device) 4 having a transfer belt 4-1 for transferring and temporarily receiving the ink printed on B;
A transfer roller device 5 having a transfer roller 5A for transferring the ink transferred to the transfer belt 4-1 onto the print paper S; a print paper supply device 7 for supplying the print paper S to the transfer roller device 5; A fixing device 9 for fixing the transferred printing ink, a paper discharging device 10 for discharging the fixed printing paper S, and a paper discharging receiving device 1 for receiving the discharged printing paper S.
1 and a cleaning device 6 for cleaning the transfer belt 4-1 after printing is completed. Further, in this configuration example, one transfer belt device 4 is disposed at the center of the printing apparatus main body, and a plurality of plate drum devices 1 are disposed corresponding to the transfer belts 4-1 of the transfer belt device 4, respectively.
A, the developing devices 3 are arranged respectively, and the writing device 2
Are arranged substantially near the upper part of each plate drum 1A, and form a transport route for the printing paper S at the lower part of the printing apparatus main body.
In the transport route, a printing paper supply device 7, a transfer roller device 5, a transport device 8, a fixing device 9, a paper discharge device 10, a paper discharge receiving device 11, and the like are sequentially arranged.

In the configuration shown in FIG. 1, in order to solve some of the problems in the conventional printing press, each device unit is arranged most effectively or rationally. And
In order to reduce the size and size of the entire apparatus, the transfer belt apparatus 4 using the transfer belt 4-1 is configured to be vertically long, and the transfer belt apparatus 4 is disposed substantially at the center of the printing apparatus. By arranging the plate drum device 1 in correspondence with the transfer belt 4-1 of the transfer belt device 4, it is possible to achieve miniaturization, compactness, and space saving.

Further, in the configuration of FIG. 1, the printing plate 1B is housed in the plate drum 1A for miniaturization and cost reduction. For this reason, a printing device of a type that supplies a plate from the outside of a plate drum, such as a stencil printing press or a waterless sheet-fed printing press, does not require a plate storage space, a plate feeding device, a plate discharging device, and the like. This configuration is far more advantageous for miniaturization and cost reduction. Further, the plate drum device 1 provided with the plate 1B and the plate drum 1A is designed to further reduce the size and cost of the entire device including the transfer belt device 4, the plate 1B, and the plate drum 1A, and to be advantageous in performance. Transfer belt 4-
1 are arranged symmetrically on the left and right sides and have a common configuration on the left and right sides.

Further, in the configuration of FIG. 1, in order to smoothly transport the printing paper S, to reduce the jam of the printing paper as much as possible, and to effectively utilize the curvature separating performance as an effective performance means of the transfer belt. In order to eliminate a large-scale separation device and to make the transport path of the printing paper from the paper supply to the transfer, fixing, and discharging almost linear, the printing paper is provided at a lower portion of the printing apparatus main body. An S transport route is formed, and the printing paper supply device 7, the transfer roller device 5, the transport device 8, the fixing device 9, and the paper discharge device 1 are formed on the transport route.
0, a paper receiving device 11 and the like are sequentially arranged.

As described above, in the printing apparatus having the configuration shown in FIG. 1, the plate drum device 1, the writing device 2, and the developing device 3 are arranged symmetrically with respect to the transfer belt 4-1. Achieving commonality, downsizing and compacting of equipment,
In order to reduce the cost and transport the printing paper, a transport route for the printing paper S is formed at the lower part of the printing apparatus main body,
Since the process from paper supply to transfer, fixing, and paper discharge is configured almost linearly, stable performance can be ensured even for conveyance of print paper.

Next, the configuration of each section of the printing apparatus shown in FIG. 1 will be described. First, in the plate drum 1A of each plate drum device 1 corresponding to each color of full-color printing, a plate supply roll 1B-1 around which an unused heat-sensitive and water-repellent printing plate 1B is wound, and a used plate Take-up roll 1
The plate supply mechanism constituted by B-2 is stored, and the unused portion of the plate sent out from the plate supply roll 1B-1 exits from the slit-shaped opening of the plate drum 1A to the outside of the plate drum 1A. After being printed, the used portion of the plate is returned to the inside of the plate drum from the slit-shaped opening of the plate drum 1A, and is taken up by the take-up roll 1B-2. . Therefore, the plate supply is automatically supplied to the surface of the plate drum by the plate supply mechanism housed in the plate drum 1A, and after the printing is completed, the used portion of the plate is automatically wound into the plate drum, and the next new plate is supplied. Plate is supplied to the plate drum surface

As can be seen from FIG. 1, the plate 1B and the plate drum 1A correspond to the full color basic colors (process colors), for example, yellow (Y), magenta (M), and cyan (C) inks. There is another plate and plate drum for black (Bk) ink for characters and inking, etc., and a plate and plate drum of four colors in total, and It has a developing device.

The writing device 2 provided on each plate drum device 1 is a thermal head (thermal writing device) configured to be able to move up and down on the plate drum 1A, and the printing device wound around the plate drum 1A. When writing data for printing on the printing plate 1B, the device descends and contacts the plate drum to write data, and then rises and stands by. Here, the heat-sensitive water-repellent printing plate 1B is made of a material having water repellency, and has a property that the water repellency when heated is lost from the properties of the material, and is opposite to the water repellency, that is, the property is changed to hydrophilic. Thus, writing can be easily performed by the thermal writing device 2 including a thermal head.

The developing device 3 provided in each plate drum device 1 prints each color (yellow, magenta, cyan, black) on the plate 1B on which the print data is written by the writing device 2 on the plate drum 1A. It is a device that supplies ink. The developing device 3 includes a developing roller 3a, an ink magazine 3e for replenishing ink, and an ink magazine 3e.
Reservoir 3d for storing the ink supplied from the developing roller 3a between the developing roller 3a, a developing blade 3c for regulating the ink in the ink reservoir 3d to an appropriate thickness and supplying the ink to the developing roller 3a, Smoothing roller 3 that rotates and oscillates to make the ink layer after passing through the developing blade more uniform
b. When an appropriate amount of ink is supplied to the developing roller 3a, the developing roller 3a of the developing device 3 is pressed against the plate drum 1A, and the ink is transferred to the portion of the plate 1B where the above-described print data is written. . As described above, the transfer of the ink from the developing device 3 to the portion corresponding to the print data of the plate 1B forms an image of the print ink on the plate drum 1A.

The transfer belt device 4, which is one of the features of the present invention, is a rubber transfer belt 4 for temporarily transferring and receiving the developed ink on the plate 1B on each plate drum 1A as described above. The transfer belt 4-1 is stretched around a plurality of rollers such as a driving roller and a driven roller. Here, FIG. 2 is a schematic configuration diagram showing the configuration of the transfer belt device.

The rubber constituting the transfer belt 4-1 is generally made of a material such as nitrile rubber or urethane rubber. The surface is given a surface roughness in consideration of the transfer of the ink from the plate drum 1A and the transfer of the ink to the printing paper. Further, inside the transfer belt 4-1 of the transfer device 4, the transfer belt 4-1 is pressed against the plate drum 1A at the time of printing at a position corresponding to each plate drum 1A, and the transfer belt 4-1 is pressed at the end of printing. A platen roller 4-2 for disengaging from the drum 1A is provided.
After an ink image is formed on the plate drum 1A, the transfer belt 4-
1, a platen roller 4-2 corresponding to the plate drum 1A on which the image is formed is transferred to the plate drum 1A by the transfer belt 4A.
-1, so that the ink image on the plate drum 1A is transferred to the transfer belt 4-1.

Each platen roller portion of the transfer belt device 4 has a platen roller 4-2 and its platen roller 4
-2 is selectively pressed to the plate drum 1A, and the pressing mechanism is swingably supported by a shaft 4-3 fixed to a side plate or the like of the transfer belt device. A lever 4-4 that pivotally supports the platen roller 4-2 at one end, and a cam follower 4-5 that is pivotally supported at the other end of the lever 4-4 and abuts the cam when selectively pressed. The platen roller 4 contacts the cam follower 4-5 via a lever 4-4.
-2 for selectively pressing the plate drum 1A against the plate drum 1A
-6 (the motor for rotating the cam and the like are not shown). The platen roller 4-2 and the pressure mechanism are provided at positions corresponding to the respective plate drums 1A. The example shown in FIGS. 1 and 2 has a total of four platen rollers 4-2 and the pressure mechanism. Is a transfer belt device 4 provided with:

When an image is formed by ink on the plate drum 1A, the transfer belt 4-1 is pressed against the plate on which the ink is placed by the action of the platen roller 4-2 and its pressing mechanism as described above. The ink is transferred to the transfer belt 4-1. In this way, the formation and transfer of the required color ink image is performed at each plate drum. In the printing apparatus of FIG. 1, yellow, magenta, cyan, and black inks necessary for color printing and the like are prepared for the four plate drums 1 </ b> A. After forming the black color ink image,
If the transfer belt 4-1 is superposed and transferred to the same position, full-color printing can be performed.

In the present invention, since a plurality of printing inks are successively received on the transfer belt 4-1 and a color image is formed on the belt, only one transfer device may be used, and a transfer device such as a conventional offset printing machine may be used. In addition, a transfer device is not required for each ink. The printing device is therefore very compact and compact. Also,
Therefore, the machine can be manufactured very cheaply. Furthermore, in the conventional multicolor printing apparatus, since ink is sequentially superimposed on printing paper, it is greatly affected by the accuracy of paper conveyance. In addition, this method is a color overlay method that depends on printing paper that is extremely unstable due to the influence of expansion and contraction of paper. On the other hand, in the printing apparatus of the present invention, since a color image is formed by sequentially overlapping ink on the transfer belt 4-1 and the color image is collectively transferred to the printing paper, measures against color misregistration and the like are very difficult. Accurate and stable color printing is possible.

In the printing apparatus of the present invention, the transfer belt 4-1 to which the ink from each plate drum has been transferred is conveyed to the lowermost end of the transfer belt device 4, and is transferred to the printing paper S by the transfer roller device 5. The ink is finally transferred onto the printing paper S. As described above, in the transfer belt device 4 according to the present invention, a plurality of types of ink images are superimposed and transferred on the transfer belt 4-1 to form a color image, which is collectively transferred to the printing paper S. On the printing paper S, the transfer order is reverse to the transfer order of the ink on the transfer belt, and that is the final image.

In general, when performing color printing, it is possible to obtain a printed image with a clear color image and excellent brightness by overlaying a dark ink on a paper and a thin ink on the paper. Therefore, the order of transferring a plurality of types of inks to the transfer belt 4-1 must be reversed from the usual thin ink, and the dark ink must be transferred later. As a specific example, if ink is superimposed and transferred onto the transfer belt 4-1 in the order of yellow (Y), cyan (C), magenta (M), and black (Bk), and this is collectively transferred to the printing paper S. On the paper, the transfer is performed in the order of Bk, M, C, and Y, so that the light color Y is at the top on the paper, and a clear and bright color print image is obtained.

The other important components of the transfer belt device 4 are a belt driving roller 4-7 for driving the transfer belt 4-1 and a tail roller 4-8 for applying tension to the transfer belt 4-1. 1 and immediately below the belt driving roller 4-7 located at the lowermost end of the transfer belt device 4.
As shown in (1), a transfer roller 5A of a transfer roller device 5 for pressing and transporting the printing paper S together with the transfer belt 4-1 is provided.

Another important configuration is a configuration for separating the printing paper from the transfer belt 4-1 in order to prevent the printing paper S after the ink transfer from being wound around the transfer belt 4-1. is necessary. Conventional printing presses employ a device that mechanically grips the paper before transfer on a transfer drum or the like to transport the paper and separate it after transfer, or a separation drum with a separation claw or the like. However, all of them are expensive and complicated in configuration, are unstable and cause paper jam.

One of the features of the transfer belt device 4 of the present invention is that a curvature separating portion utilizing the characteristics of the belt is provided in a part of the transfer belt as a means for solving such a problem. That is, as shown in FIG. 2, the transfer belt device 4 of the present invention is provided with a separation roller 4-9 having a diameter as small as possible at a position where the printing paper after transfer is separated. The curvature of the belt portion hung on the belt is made very small. For this reason, the printing paper S has a portion where the stiffness of the paper itself and the curvature of the transfer belt 4-1 are small (the portion applied to the separation roller 4-9:
By the action of the separation unit, the printing paper is conveyed so as to be naturally peeled without being wound around the belt, and the printing paper is automatically separated from the transfer belt 4-1 and sent to the conveyance device 8 side.

When the transfer belt 4-1 is driven by the drive roller 4-7 as shown in FIGS. 1 and 2, the transfer belt 4-1 meanders, and the transfer belt 4-1 moves between the transfer belt and the belt drive roller. The problem of slippage due to slippage is inevitable. In addition, since the transfer belt according to the present invention has a function as an intermediate transfer member for an ink image, the accuracy of the pixel size (about 50 μm), which is the minimum unit of the image, can be adjusted in the belt running direction and the lateral direction (belt (In the width direction), the required accuracy is obtained at the time of driving.

Therefore, the transfer belt device 4 of the present invention is configured so that drive control can be performed in both the running direction and the lateral direction of the belt. For example, for meandering control in the belt lateral direction,
Control is performed such that the axis of the tail roller 4-8 is inclined by a motor or the like (not shown) in a direction to suppress the meandering of the belt. In the running direction of the belt, the belt driving roller 4
The traveling speed is controlled by a separate motor (not shown) directly connected to -7. For these controls, it is necessary to electrically detect the position in the running direction and the lateral direction of the belt.

For this reason, in the transfer belt device of the present invention, FIG.
As shown in FIG. 5, the transfer belt 4 includes an electric sensor 4-13 for detecting the presence or absence of the transfer belt 4-1 and for electrically detecting and controlling the transfer speed and the transfer amount of the transfer belt 4-1. -1 is provided at the end portion with any detection unit required for detection by the electric sensor 4-13, for example, a small hole 4-1.
0, or any one of a reflective material, a marker 4-11, and a notch 4-12. When the transfer belt 4-1 is driven, these detection units are detected by the electric sensor 4-13, and meandering control in the lateral direction of the belt and speed control in the belt traveling direction are performed. No good transfer image can be obtained. In addition, as the electric sensor 4-13, a transmission type or a reflection type configuration including a light emitting element and a light receiving element, and the detection unit detects light using light and converts it into an electric signal by photoelectric conversion, Various types can be used, such as a type that detects passage of the detection unit as a change in capacitance, or a type that uses a magnetic substance as a marker of the detection unit and magnetically detects and converts it into an electric signal.

As another example of the transfer of the transfer belt,
Using a transfer belt with a toothed guide on the back of the belt, the transfer device may be configured to have a drive mechanism that drives the belt by engaging with the toothed guide of the transfer belt, and may be configured to prevent slippage in the running direction of the belt. The belt can be precisely conveyed.

In the printing apparatus shown in FIG. 1, the transfer roller device 5 installed opposite to the lower portion of the transfer belt device 4 applies the printing ink on the transfer belt 4-1 to the printing paper S.
Roller 5A for transferring pressure to the transfer roller 5A, and the transfer roller 5A
Mechanism 5B (consisting of a transfer roller support arm, a cam, a spring, etc.
A mechanism that swings the arm with a cam to move the roller into and out of contact. Then, when the printing ink on the transfer belt 4-1 comes just below, the printing paper supply device 7
And the printing paper S is supplied by the registration rollers 7A,
At this time, the transfer roller 5A is brought into contact with the transfer belt 4-1 to transfer the printing paper to the transfer belt 4-1.
And the paper is conveyed to transfer the printing ink on the transfer belt 4-1 to the printing paper.

The cleaning device 6 includes a transfer belt 4-1.
This is a function of cleaning the transfer belt 4-1 when the printing ink is transferred to the printing paper S and the printing is completed. In preparation for the next printing, the transfer belt 4 is cleaned by a cleaning roller (or a cleaning brush) or a cleaning blade. −
1. Remove residual ink from the previous print from above and clean.

The printing paper supply device 7 includes a storage section for the printing paper S, a paper feeding roller, and the like, and feeds the printing paper S one by one toward the transfer section at a timing of printing.

In the example shown in FIG. 1, the transport device 8 comprises a transport belt, and transports the printing paper S to which the printing ink has been transferred and separated from the transfer belt 4-1 to the fixing device 9 in the next step.

The fixing device 9 is a device for firmly fixing the ink in a dry state on the printing paper S to the paper.
A, and a pressure roller 9B that presses against the fixing roller 9A. In the fixing of the printing ink, the fixing roller 9A is made of an oil-resistant rubber (for example, a silicone rubber, a fluorine rubber, or the like) that absorbs the solvent of the printing ink. It is a configured roller. Further, if a heat source (electric heater, halogen lamp, or the like) for promoting fixing is provided inside the fixing roller, better fixing can be achieved.

The printing paper S after fixing is discharged out of the apparatus by a paper discharging device 10 composed of a pair of rollers and the like, and the discharged printing paper S is discharged to a paper discharging receiving device installed on the side of the printing apparatus main body. The paper is discharged onto a tray 11.

[0040]

As described above, in the printing apparatus according to the first aspect, the printing plate drum for storing and holding the plate, and the heat-sensitive water-repellent printing plate stored and held on the plate drum are provided. A writing device for writing data to be printed on the plate on the plate drum, a developing device for supplying printing ink to the plate on the plate drum, and transferring and receiving the ink supplied to the plate on the plate drum A transfer device having a transfer member, a transfer roller device for transferring the ink transferred to the transfer member to printing paper, a printing paper supply device for supplying printing paper to the transfer roller device, and the transfer member after printing is completed. Since it has a cleaning device for cleaning as a basic configuration, it uses a heat-sensitive water-repellent printing plate,
It is possible to provide a printing apparatus having a novel configuration that has never been provided, and to provide a small, compact, and low-priced printing apparatus as compared with conventional offset printing presses and stencil printing presses.

In the printing apparatus according to the present invention, the transfer body of the transfer apparatus is formed of a transfer belt, and the transfer apparatus receives a plurality of types of ink used for printing from the plate drum on the transfer belt, and prints the printing paper. Since it is characterized by taking a method of transferring multiple types of ink at once, only one transfer device is required, and like a conventional color offset printing machine,
The machine cost can be very low compared to one having a separate transfer blanket drum for each color. In addition, since a color image is formed by superimposing a plurality of inks on one transfer belt, and the color image is collectively transferred to transfer paper, the superposition of each ink can be performed with high accuracy, so-called color misregistration. Color printing can be easily performed without any problems.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, when transferring and receiving the ink from the plate drum to the transfer belt of the transfer device, the ink having a low density among the plurality of inks is used. It is characterized by an ink transfer method that transfers from the transfer belt to the transfer of the ink with the darker density sequentially, so that the images that are collectively transferred from the transfer belt onto the printing paper are lower for darker ink and higher for lighter ink. As a result, it is possible to obtain a clear color print image having excellent brightness and the like.

More specifically, in the case of color printing, in general, the printing ink is printed such that the darker the ink is, the lower the ink is on the paper, and the thinner the ink is, the more the color image is superimposed on the dark ink. Printing is performed. In order to do so, the ink is usually printed on paper in order from dark ink. However, the printing apparatus of the present invention employs a method in which a plurality of types of inks are once superimposed and transferred onto a transfer belt and then collectively transferred onto transfer paper. Transfer by overlapping. In such a case, the transfer order of the image transferred from the transfer belt to the printing paper is reversed, with the darker ink being lower and the lighter ink being higher. in this way,
In the printing apparatus of the present invention, the transfer order of the ink images of each color on the transfer belt is the reverse of the printing method in which the inks of the respective colors are superimposed on the conventional printing paper. Since the light-colored ink is arranged above the dark-colored ink, it is possible to obtain a clear color print image with excellent brightness and the like.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a printing apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a transfer device provided in the printing apparatus shown in FIG.

FIG. 3 is a perspective view illustrating an outline of a transfer belt, an electric sensor, and a detection unit of the transfer device illustrated in FIG. 2;

[Explanation of symbols]

 1: Plate drum device 1A: Plate drum 1B: Heat-sensitive water-repellent printing plate 1B-1: Plate supply roll 1B-2: Take-up roll 2: Writing device 3: Developing device 4: Transfer belt device (transfer device) 4 -1: Transfer belt (transfer) 4-2: Platen roller 4-3: Shaft 4-4: Lever 4-5: Cam follower 4-6: Cam 4-7: Belt drive roller 4-8: Tail roller 4 -9: Separation roller 4-10: Small hole 4-11: Reflector or marker 4-12: Notch 4-13: Electric sensor 5: Transfer roller device 5A: Transfer roller 6: Transfer belt cleaning device 7: Printing paper supply device 8: Conveying device 9: Fixing device 10: Discharge device 11: Discharge receiving device

Claims (2)

[Claims] A printing apparatus using a heat-sensitive water-repellent printing plate, comprising: a printing plate drum for storing and holding the plate; a heat-sensitive water-repellent printing plate stored and held on the plate drum; A writing device that writes data to be printed on a plate on the plate drum, a developing device that supplies printing ink to the plate on the plate drum, and a transfer body that transfers and receives the ink supplied to the plate on the plate drum , A transfer roller device for transferring the ink transferred to the transfer body to printing paper, a printing paper supply device for supplying printing paper to the transfer roller device, and cleaning the transfer body after printing is completed The transfer device of the transfer device includes a belt-like member (hereinafter, referred to as a transfer belt), and the transfer device includes a plurality of types of ink used for printing. Receiving a click on the transfer belt from the plate drum, the printing apparatus characterized by taking a method for transferring a plurality of kinds of ink at a time to the printing paper. 2. The printing apparatus according to claim 1, wherein when transferring the ink from the plate drum to the transfer belt of the transfer device and receiving the ink, the ink is transferred from the ink having the lower density to the ink having the higher density sequentially from the plurality of inks. A printing apparatus, which employs an ink transfer method that shifts to a transfer of the ink.