Patent Grant
8042463
1. Field of the Invention
The present invention relates to a coating device and a coating unit in a stencil printing apparatus, and more particularly, to a coating device in a stencil printing apparatus in which the surface of a sheet printed using a stencil printing apparatus is coated with a viscous coating liquid such as a UV-curable varnish or the like, and to a coating unit that is mounted on a printing apparatus main body in place of a detachable printing drum unit.
2. Description of the Related Art
Known simple printing apparatuses include, for instance, digital heat-sensitive stencil printers (hereinafter, simply “stencil printing apparatuses”) for digital heat-sensitive stencil printing. In such stencil printing apparatuses, a thermal head, having a plurality of small heat generators arranged in a main scanning direction, is brought into contact with a thermosensitive stencil master (hereinafter “master”), also called stencil paper, as the master is transported in a sub-scanning direction (master transport direction) that is perpendicular to the main scanning direction, while the heat generators are energized in pulses to thereby heat-melt punch the master in accordance with image information. The perforated master is wrapped around the outer peripheral face of a porous circular plate cylinder that is provided on the outer periphery of a printing drum, whereafter the outer peripheral face of the plate cylinder is pressed by a pressing means such as a press roller or the like, with printing paper (hereinafter also simply “paper”), as the medium to be printed, interposed therebetween. As a result, ink that is supplied to the inner peripheral face of the plate cylinder bleeds from the perforated portion of the plate cylinder and the perforated part of the master, whereupon the ink is transferred to the paper to yield a printed image. The printing drum is also referred to hereinafter as simply “drum”.
The above stencil printing apparatuses, having low running costs and being operable at high speed, are extensively used for printing circulars, forms and the like in, for instance, the education market, but also in public offices, associations, hospitals and so forth, and for printing large runs of newspaper inserts, real estate advertisements, internal memos in private businesses and the like. That is because such inexpensive apparatuses enable easy printing by anyone at any time.
The printing paper used herein is ordinary paper or recycled paper, thus relatively inexpensive, the surface of which exhibits high ink penetration. This makes the images on the surface of the printed product look dull and drab. Also, the print image ink may dry apparently by penetrating into the fibers of the paper. Ordinarily, special fixing devices do not achieve complete fixing, and hence the resulting printed product is inferior from the viewpoint of storability, since rubbing thereof with the fingers may give rise to smears, while the printed product itself may become weakened if wet with water.
Known methods for imparting a stylish feel, as well as storability and abrasion resistance, to such printed products, include, for instance, lamination methods in which a transparent film is affixed to the surface of the printed product. Lamination, however, is time-consuming, and hence a low-productivity method, and is also problematic in that it requires a special device, called laminator, for heat fusion, and in that films are expensive.
Meanwhile, varnish coating devices are also known for imparting a stylish feel, as well as storability and abrasion resistance, to printed products. Varnish coating devices are dedicated devices for applying a transparent varnish on the surface of the printed product while the latter is being transported. Such devices are relatively bulky and expensive, and hence varnish coating was not something that could be done by anyone, readily and inexpensively.
Conventional varnish coaters are full-fledge coaters in which varnish is often applied over the entire surface of the printed product. These coaters are thus large equipment items that are used in printing establishments. Given that such equipment is large, expensive and requires trained personnel for its operation, no equipment has been known thus far that allows the user him/herself to coat with varnish an ordinary printed product, easily and quickly. Moreover, after coating the entire surface of the printed product with varnish, the periphery of the printed product is cut off. This requires an expensive dedicated paper cutter, which only printing establishments can afford.
Specifically, Japanese Patent Application Laid-open No. 2007-111873 (Prior Art 1) and 2006-76080 (Prior Art 2) disclose water-based varnish coating devices in large offset printing apparatuses.
Also, Japanese Patent Application Laid-open No. 2006-35816 (Prior Art 3) discloses a relatively small-size independent dedicated varnish coating device.
Japanese Patent Application Laid-open No. 2004-313829 (Prior Art 4) discloses a varnish coating device and a printer, in which a UV-curable varnish is sprayed, by liquid spraying nozzles, onto a specific area of printing paper, followed by curing through UV irradiation.
Since the above-described digital stencil printing apparatuses enable easy printing by anyone, inexpensively and by way of a simple operation, they are also widely used by free operators for printing relatively small runs. Japanese Patent Application Laid-open No. 2006-281711 (Prior Art 5) describes such a stencil printing apparatus, having a plurality of printing drum units that can be detachably mounted on the main body of the stencil printing apparatus, wherein a UV-radiating unit can be mounted in the place of a printing drum unit holding ordinary ink, when a printing drum unit holding a UV-curable ink is mounted upstream of a paper transport direction.
The water-based varnish coating devices disclosed in Prior Art 1 and Prior Art 2, however, are bulky and expensive, and hence not suitable for ordinary users. The varnish coating device of Prior Art 3 is relatively small, but is likewise expensive and unsuitable for ordinary users. Similarly, the varnish coating device of Prior Art 4 is costly and inappropriate for ordinary users.
Stencil printing apparatuses have involved heretofore mainly black printing on ordinary paper, plus occasional use for color printing in red or blue. The above-described drawbacks of inferior storability and poor aesthetics of the surface of printed products obtained in a stencil printing apparatus have become a stereotype, and hence the use of a stencil printing for varnish coating has been deemed unfeasible, or in other words, few considered the potential worth of using varnish coating.
In the light of the above, it is a main object of the present invention to realize and provide a coating device that uses an ordinary conventional digital stencil printing apparatus, such that the coating device allows anyone to easily apply a uniform film of a viscous coating onto a predetermined area of, for instance, covers and surfaces of printed products. In other words, an object of the present invention is to realize and provide a coating device and a coating unit that double as a stencil printing apparatus. In particular, it is an object of the present invention to provide a coating device and a coating unit having the function of applying a UV-curable varnish on the surface of a printed product.
In an aspect of the present invention, there is provided a coating device in a stencil printing apparatus in which printing drum unit whose outer peripheral face is wrapped with a prepared master can be detachably mounted on a printing apparatus main body. A coating unit that can be detachably mounted on the printing apparatus main body, in place of the printing drum unit, for forming a coating in a given thickness of a viscous coating liquid onto a predetermined area of a surface of a printed sheet that is fed.
In another aspect of the present invention, there is provided with a coating unit mounted on and detached from, in place of a printing drum unit whose outer peripheral face is wrapped with a prepared master, a printing apparatus main body of a stencil printing apparatus that can be detachably mounted on the printing apparatus main body. A coating is formed in a given thickness of a viscous coating liquid onto a predetermined area of a surface of a printed sheet. The coating unit comprises: a coating member for coating the surface of a printed sheet with a coating liquid; a supply device for forming a liquid pool, where the coating liquid accumulates temporarily, on the coating member, and for supplying the coating liquid to form a coating in a predetermined thickness to the surface of the coating member; a holding member for holding a coating liquid storage container that contains the coating liquid; and a pump device for feeding the coating liquid from the coating liquid storage container to the liquid pool.
The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description taken with the accompanying drawings in which:
An embodiment of the present invention is explained next with reference to accompanying drawings.
With reference to
In the overall apparatus illustrated in
The paper-feeding tray 1, the pickup roller 3, the separation roller 4, the separation pad 5, the upper resist roller 6, the lower resist roller 7 and so forth make up a paper feeding section device or a paper feeding device, as a sheet feeding device.
In the coating section, the printed paper 2, fed at a predetermined timing by the upper resist roller 6 and the lower resist roller 7, is coated with a transparent UV-curable varnish (referred to hereinafter also as “varnish” or “varnish liquid”), as a viscous coating supply, by way of a coating roller 8, as a feeding coating member, which applies the transparent UV-curable varnish, to a predetermined thickness, onto the surface of the paper 2. The printed paper 2 is pressed against the coating roller 8 by a press roller 9, as a pressing member, whereby the surface of the printed paper 2 becomes coated with the varnish liquid.
An UV-curable varnish comprising, for instance, a monomer not using an organic solvent or the like as a raw material, a reaction initiator, a body pigment or the like is preferably used as the UV-curable varnish, from the viewpoint of handleability and superior environmental compatibility.
The printed paper 2, having thus been coated with varnish, is released from the coating roller 8 by air pressure from blown air coming from an air discharge fan 11, as an air release means, and an air separation pawl 10, as an air release means. The paper is then transported leftward in the figure by a paper output transport device 12. The paper output transport device 12 comprises a front roller 13, a back roller 14 and a plurality of endless belts 15 spanning therebetween, the back roller 14 being rotated by a driving motor 16, as a result of which the endless belts 15 are rotationally driven. The paper output transport device 12 comprises also a duct 17 with a built-in air suction fan, for suctioning the reverse face of the printed paper 2 and bringing the latter into contact with the endless belts 15. A below-described driving mechanism or the like (not shown) limits and controls the pressure range of the press roller 9 against the coating roller 8, in such a manner that no direct pressure is exerted on portions where there is no paper.
As illustrated in
In
The stencil printing apparatus 50 in
From the above it follows that the varnish coating device 39 in the stencil printing apparatus 50 refers basically to a varnish coating device 39 using a conventional stencil printing apparatus 50 for digital master making, in other words, a varnish coating device 39 that doubles as the stencil printing apparatus 50.
In
The UV-radiating device 51 comprises a printed product transport device 52 for transporting the printed paper 2, which is the received printed product. The printed product transport device 52 comprises a front roller 53, a back roller 54 and a plurality of perforated endless belts 55 spanning therebetween, the back roller 54 being rotated by a driving motor 56, as a result of which the perforated endless belts 55 are rotationally driven. The printed product transport device 52 comprises also a duct 57 with a built-in air suction fan, for suctioning the reverse face of the printed paper 2 and bringing the latter into contact with the perforated endless belts 55.
Above the printed product transport device 52 there is provided a UV-radiating unit 58 for irradiating UV rays onto the print image surface of the printed paper 2. The UV-radiating unit 58 comprises a plurality of UV-ray lamps 59, such as high-pressure mercury lamps, metal halide lamps or amalgam lamps, a reflective plate 60 formed by, for instance, an aluminum plate, and a cover casing 61 provided outward of the reflective plate 60.
The printed paper 2 transported by the printed product transport device 52 is irradiated with direct UV rays from the UV-ray lamps 59 and with UV rays reflected by the reflective plate 60. The surface varnish coated onto the printed paper 2 becomes cured and fixed thereby, after which the paper is stacked on a paper output tray 62, as a paper output tray.
In
The constituent elements of the varnish coating unit 20 are explained next with reference to
The varnish coating unit 20 is built to be detachably mountable on the above-described mounting section of the printing apparatus main body 100 illustrated in
As partially explained above, the varnish coating unit 20 comprises, for instance, the coating roller 8, as a feeding coating member, which applies a transparent varnish liquid to the surface of the printed paper 2; a supply device for forming a liquid pool 22, where the varnish liquid accumulates temporarily, on the coating roller 8, and for supplying varnish liquid, to a predetermined thickness, over a predetermined area of the surface of the coating roller 8; a cradle 24A, as a holding member, for detachably holding a varnish container 24 as a coating liquid storing container for storing the varnish liquid; a pump device 26 for feeding varnish liquid from the varnish container 24 to the liquid pool 22; and a liquid supply pipe 23, connected to the pump device 26, for feeding varnish liquid to the liquid pool 22.
The coating roller 8 is rotatably pivoted and held by a rear unit chassis 30 and a front unit chassis 31, as stationary members comprised in the varnish coating unit 20. The coating roller 8 is rotationally driven in the direction of the arrow in the figure (clockwise direction) by a driving mechanism comprising a driving means, not shown. In terms of standardizing the main body constitution on the side of the stencil printing apparatus 50, such a driving mechanism comprises preferably couplings or the like, as driving force connection means, and driving force transmission means such as gears, belts or the like, not shown, for connecting and transmitting, for instance, the rotation driving force from a main motor, as a drum driving means, for rotationally driving the printing drum 70 illustrated in
A doctor roller 21 is disposed in the vicinity of the coating roller 8, parallel thereto and with a predetermined gap between the doctor roller 21 and the coating roller 8. The liquid pool 22 forms on top of the coating roller 8 and the doctor roller 21. The doctor roller 21 pivots rotatably on the rear unit chassis 30 and the front unit chassis 31, in such a manner so as to be capable of rotating in the opposite direction of that of the coating roller 8. The varnish container 24, which stores a predetermined amount of varnish liquid and which can be detachably mounted on the cradle 24A of the varnish coating unit 20, is mounted/set on the cradle 24A provided in the varnish coating unit 20. The cradle 24A forms substantially a chassis shape with openings on the upper and lower portions thereof.
The supply device for forming a liquid pool 22, where the varnish liquid accumulates temporarily, on the coating roller 8, and for supplying varnish liquid, to a predetermined thickness, over a predetermined area of the surface of the coating roller 8, comprises mainly the doctor roller 21, as a coating liquid measuring member for supplying varnish liquid while measuring the varnish liquid in such a manner that the surface of the coating roller 8 carries a film of varnish liquid of a predetermined thickness, and the supply range varying means illustrated in
The mechanism of the varnish feeding pump 26 may comprise a simple gear pump or a tube pump. The varnish feeding pump 26 may also be a reciprocating pump or the like. The varnish feeding pump 26 is driven by a pump motor 26A. Driven thus by the pump motor 26A, the varnish feeding pump 26 suctions varnish liquid through a cap 25 of the varnish liquid container 24, and transports the varnish liquid, via the liquid supply pipe 23, to supply the liquid pool 22.
Preferably, the coating roller 8 is shaped as a gravure roller having multiple small recesses on its surface. In that case, virtually no gap need be provided between the doctor roller 21 and the coating roller 8.
A liquid amount detecting sensor 27, comprising a liquid detection needle 27a, is disposed/set at the liquid pool 22. The liquid amount detection sensor 27 detects the size of the liquid pool 22, i.e. the amount of varnish liquid, on the basis of the same principle as an ink amount detection sensor 48 comprising an ink detection needle 48a illustrated in
The air separation pawl 10 separates and releases the printed paper 2 from the coating roller 8 by jetting downwards compressed air that is fed by a driving device not shown. The above various components, which are all comprised in the varnish coating unit 20, can be detachably mounted on the mounting section of the printing apparatus main body 100 together with the varnish coating unit 20.
The broken-line circle in
The guide rails 18a, 18b and the unit rails 28a, 28b constitute the mounting/detachment means or insertion/detachment means that allow the varnish coating unit 20 to be detachably mounted on, or inserted into, the mounting section of the printing apparatus main body 100. The mounting section of the printing apparatus main body 100 refers to the site at which the varnish coating unit 20 is slidably set, along the guide rails 18a, 18b, extending from the front of the paper towards the back thereof, in
The supply range varying means for modifying the varnish liquid supply length, as a coating liquid supply length in the paper width direction (sheet width direction) Y of the liquid pool 22 is explained next with reference to
The spacing between the respective ends of the partition plates 32a, 32b can be modified, through the rotation of the lead screw 33, in a direction along which the partition plates 32a, 32b are brought closer to or separated from each other by an equal amount. The lower end faces of the partition plates 32a, 32b are formed to a shape that allows the partition plates 32a, 32b to slide while in contact with the outer peripheral face of the upper half portions of the coating roller 8 and the doctor roller 21. The top faces of the partition plates 32a, 32b are guided by rail-shaped guiding members, not shown, fixed to the rear unit chassis 30 and the front unit chassis 31, as a result of which the partition plates 32a, 32b are supported so as to be movable only in the paper width direction, without change of the attitude of
Although omitted in
On a rear side plate 19 on the side of the printing apparatus main body 100 there is arranged the unit discrimination sensor 37 as a unit type detection means for detecting whether either the varnish coating unit 20 or the drum unit 40 illustrated in
An operation panel 90 shared by the stencil printing apparatus 50 and the varnish coating unit 20 is explained next with reference to
The mode selection key 91a functions as a mode selecting and setting means for selecting and setting a stencil printing mode, in which printing is carried out by mounting the drum unit 40 illustrated in
The platemaking start key 92 functions as a start setting means for initiating a series of operations beginning with a platemaking operation, the print start key 94 functions as a printing start means for initiating a regular printing operation of a set number of printing sheets, and the numerical keyboard 93 functions as a register setting means for registering, for instance, the number of print sheets. The liquid crystal display 95, like for instance the liquid crystal (64) illustrated in FIG. 2 of Japanese Patent Application Laid-open No. 2006-281658, displays various settings and/or detection status, as needed, on the basis of a hierarchic display structure.
The configuration of a main control system of the varnish coating device 39 and the stencil printing apparatus 50 is succinctly explained next with reference to
In the figure, the controller 68 comprises a microcomputer in which, for instance, a CPU (central processing unit), an I/O (input/output) port, a ROM (reading only memory), a RAM (random access memory), a timer and so forth, none of which are shown, are connected by way of a signal bus, not shown. The controller 68 is provided at a control board arrangement section in the printing apparatus main body 100.
The CPU of the controller 68 (hereinafter referred to simply as the “controller 68”, for the sake of simplicity) has the function of controlling the various motors and so forth, as well as controlling the driving means of a platemaking and plate feeding driving circuit 67, such as the platemaking device 65. The CPU of the controller 68 has also the function of controlling a document reading operation, the plate discharge operation, the paper feeding operation, as well as of controlling the liquid crystal display 95 of the operation panel 90, on the basis of, for instance, various signals from the control panel 90, detection signals from the various above-described and below-described sensors provided in the varnish coating device 39 and the stencil printing apparatus 50, and on the basis of operation programs, relational data and the like, called from the ROM. In the present embodiment, moreover, the CPU of the controller 68 functions as a control means for carrying out the below-described distinctive control.
The operation programs, necessary relational data and the like for the entire stencil printing apparatus 50 and varnish coating device 39 are stored beforehand in the ROM. The operation programs can be arbitrarily called by the CPU. The RAM has, for instance, the function of temporarily storing computation results of the CPU, and of storing, on demand, on/off signals and data signals that are set and inputted by the various sensors and the various keys on the operation panel 90.
The controller 68 functions as a first through eighth control means that perform the below-described controls while referring to operation programs and so forth called from the ROM.
A supplementary explanation follows next, with reference to
As specific examples of the sheet width size detection means and sheet transport direction size means there can be used, for instance, means similar to the paper size detection sensors (117) of the paper size detection means (109) (horizontal size detection sensors (118a, 118b) and vertical size detection sensors (119a, 119b, 119c)) described in paragraphs [0122] to [0125] and illustrated in FIG. 11 of Japanese Patent Application Laid-open No. 2003-312914. That is, the paper width detection sensors 118a, 118b in
With reference to
The drum unit 40 comprises mainly an ink roller 41, as an ink supply member, for supplying ink to the inner peripheral face of the plate cylinder 70a; a doctor roller 42 disposed parallelly to the ink roller 41, with a predetermined gap therebetween, for forming an ink pool 43 between the ink roller 41 and the doctor roller 42; a cradle (not shown) into which there is detachably mounted an ink container 45, as an ink storage container for storing a predetermined amount of ink; an ink feeding pump 47 for feeding ink from the ink container 45 to the ink pool 43; and an ink supply pipe 44 connected to the ink feeding pump 47, for supplying ink to the ink pool 43.
The ink roller 41 is rotatably pivoted and held by a unit side plate (not shown), which is a stationary member comprised in the drum unit 40, and is rotationally driven in the arrow direction of the figure (clockwise direction). Such a driving mechanism comprises preferably couplings or the like, as driving force connection means and driving force transmission means such as gears, belts or the like, not shown, for connecting and transmitting, for instance, the rotation driving force from a main motor as a drum driving means for rotationally driving the printing drum 70. The doctor roller 42 is supported on the ink side plate in such a way so as to be rotatable in a direction opposite to that of the ink roller 41. The doctor roller 42 functions as an ink measuring member for supplying ink by measuring a predetermined thickness of film-like ink carried on the surface of the ink roller 41.
The ink container 45, which stores a predetermined amount of ink, is detachably mounted/set on the above-described cradle of the drum unit 40. The mechanism of the ink feeding pump 47 may comprise a simple gear pump. The feeding pump 47 may also be a reciprocating pump or the like. The ink feeding pump 47 is driven by an ink pump motor 47A. Driven thus by the ink pump motor 47A, the ink feeding pump 47 suctions ink through a cap 46 of the ink container 45, and transports the ink, via the ink supply pipe 44, to supply the ink pool 43.
An ink amount detecting sensor 48, comprising an ink detection needle 48a, is disposed/set at the ink pool 43. The ink amount detection sensor 48 comprising the ink detection needle 48a, is a well-known sensor that detects the size of the ink pool 43, namely the quantity of ink, for instance on the basis of capacitance. When the ink amount detection sensor 48 detects that the amount of ink has diminished, the controller 68 illustrated in
The above various components, which are all comprised in the drum unit 40, can be detachably mounted on the mounting section of the printing apparatus main body 100 together with the drum unit 40.
In
The guide rails 18a, 18b and the unit rails 49a, 49b make up a mounting/detachment means or an insertion/detachment means that allows the varnish drum unit 40 to be detachably mounted on, or inserted into, the mounting section of the printing apparatus main body 100. The mounting section of the printing apparatus main body 100 refers to the site at which the drum unit 40 is slidably set, along the guide rails 18a, 18b, extending from the front of the paper towards the back thereof, in
A prepared master 71 is wrapped around the outer periphery of the cylindrical plate cylinder 70a. A master damper 72 for holding a leading end of the prepared master 71 is openably and closably mounted on one generatrix of the outer periphery of the plate cylinder 70a. When the printing drum 70 occupies a plate feeding position, for temporarily clamping the prepared master 71 fed by the platemaking device 65 illustrated in
A pressing force varying means 96 and a pressure range varying means, which constitute the pressure mechanism of the press roller 9, are explained next with reference to
As shown in
In
The pressing force varying means 96 is a mechanism for changing the pressing force with which the press roller 9 presses the printed paper 2 against the plate cylinder 70a or the coating roller 8. The pressing force varying means 96 comprises mainly the above tension spring 83; a pressing force varying motor 84 fixed to the printing apparatus main body 100; a gearwheel 85 swingably supported on the printing apparatus main body 100, and having a female thread in the center, for screwing onto the lead screw 86; and the lead screw 86, onto which the female thread of the gearwheel 85 is screwed, and capable of moving only in the paper transport direction X.
The pressing force with which the press roller 9 presses the printed paper 2 against the plate cylinder 70a or the coating roller 8 is modified through the displacement of the lead screw 86, in the arrow direction in the figure, on account of the rotation of the gearwheel 85 driven by the pressing force varying motor 84.
When the drum unit 40 is mounted, pressure is turned on, within a pre-defined range, by the pressure relief cam 82. The pressing force required herein is substantial, of 147 to 196 N (15 to 20 kgf), for which reason such a cam mechanism is used.
When the varnish coating unit 20 is mounted, on the other hand, the varnish liquid can be applied with a smaller pressing force than in stencil printing. Specifically, a pressing force of about 49 to 98 N (5 to 10 kgf) is sufficient for varnish liquid application. Therefore, the pressing force varying motor 84 is driven to shorten the length of the tension spring 83 vis-à-vis the length during stencil printing. The pressure force is changed thereby to a lower value, and use of the pressure relief mechanism by the pressure relief cam 82 is avoided. That can be achieved by turning off the rotation of the pressure relief cam 82 by way of, for instance, an electromagnetic clutch mechanism. To that effect there can be used known methods such as those described above, and hence a detailed explanation thereof is omitted.
Instead of using a pressure relief mechanism, pressure is relieved in
This method allows turning the pressure on and off within an arbitrary range. As a result, the press roller 9 can be pressed against the coating roller 8 within an optimal pressure range in accordance with the paper size (paper length) in the paper transport direction, detected by the paper length detection sensors 119a through 119c. Control may be carried out herein in such a manner that the pressure is turned on within the range corresponding to the varnish coating area L illustrated in
An explanation follows next on the operation control flow of the varnish coating device 39 in the stencil printing apparatus 50 of the present embodiment, on the basis of the flowchart of
In step S1, there is firstly checked whether the mode is a stencil printing mode. Specifically, when the user presses the mode selection key 91a in
When the LED (light-emitting diode) for stencil printing mode setting is lit up, indicating that the stencil printing mode is set, it is checked whether the platemaking start key 92 is pressed or not. If the platemaking start key 92 is pressed, it is checked whether or not the drum unit 40 is mounted on the mounting section of the printing apparatus main body 100, when the series of stencil printing operations reach the start setting state,(step S2, step S3).
On the other hand, when the LED (light-emitting diode) for varnish coating mode setting is lit up, indicating that the varnish coating mode is set, it is checked whether or not the varnish coating unit 20 is mounted on the mounting section of the printing apparatus main body 100 (step S12, step S13).
In step S3 and step S13, the controller 68 functions as a seventh control means. Specifically, the controller 68 performs control so as to permit the inputs and operations for executing the stencil printing mode when the stencil printing mode is selected and set, through pressing of the mode selection key 91a, and the unit discrimination sensor 37 detects that the drum unit 40 is mounted, and so as to permit the inputs and operations for executing the varnish coating mode when the varnish coating mode is selected and set, through pressing of the mode selection key 91b, and the unit discrimination sensor 37 detects that the varnish coating unit 20 is mounted.
When in step S3 the unit discrimination sensor 37 does not detect that the drum unit 40 is mounted, the liquid crystal display 95 of the control panel 90 of
On the other hand, when in step S13 the unit discrimination sensor 37 does not detect that varnish coating unit 20 is mounted, the liquid crystal display 95 of the control panel 90 displays a varnish coating unit mounting warning to the effect of “please mount varnish coating unit” (step S23). The warnings in step S12 and step S23 may also be carried out concomitantly with blinking of the LEDs or the like accompanied with the sound of a buzzer or the like, not shown.
In step S2 through step S5, and step S13 through step S22, the controller 68 functions as an eighth control means. Specifically, when the unit discrimination sensor 37 detects that the drum unit 40 is mounted, and start is set by way of the platemaking start key 92 (start setting means), the controller 68 permits the plate feeding driving circuit 67 to execute a plate perforation step in step S4 and a plate feeding and wrapping step in step S5 (platemaking operation and plate feeding operation). When the unit discrimination sensor 37 detects that the varnish coating unit 20 is mounted, the controller 68 prohibits the plate feeding driving circuit 67 from executing a plate perforation step in step S4 and a plate feeding and wrapping step in step S5 (platemaking operation and plate feeding operation, even when start is accidentally set by way of the start key 92 (start setting means).
The below well-known series of stencil printing operations are executed thus when the stencil printing mode is selected and set, namely when the platemaking start key 92 is pressed and the unit discrimination sensor 37 detects that the drum unit 40 is mounted.
Specifically, an original is set on an original reading device, not shown, and paper 2 is appropriately replenished in the paper-feeding tray 1, as preparations for the stencil printing operation. Then, upon pressing the platemaking start key 92, a plate discharge step (plate discharge operation) is carried out first. That is, a used master wrapped around the plate cylinder 70a in
Next, the master clamper 72 is closed by an opening and closing device not shown, when the controller 68 judges that the leading end of the prepared master 71 has reached the master clamper 72 of
A plate printing step is carried out next in which the above-described paper feeding device transports one sheet of paper 2, and in which ink seeping through the inner peripheral face of the plate cylinder 70a is supplied to the prepared master 71 on the outer peripheral face of the plate cylinder 70a, whereupon the ink becomes closely adhered, on account of the inventions adherence, to the outer peripheral face of the plate cylinder 70a (step S6).
Once the plate printing step is over, the user checks the printed image position and the image quality of the plate-fixing printed product. Based on the check results, appropriate test runs are printed, after which the user inputs, via the numerical keypad 93, the number of required normal printed sheets, and presses the print start key 94, whereupon the printing drum 70 is rotationally driven. The pickup roller 3 and the reverse roller 4 of the sheet-supply device are also rotationally driven, thereby initiating the transport of the paper 2, followed by the above-described stencil printing step and paper output step. All the steps of the stencil printing operation are over once the set number of sheets of paper 2 is printed (step S7 to step S11).
Next, when the varnish coating mode is selected, in step S13, and the unit discrimination sensor 37 detects, in step S14, that the varnish coating unit 20 is mounted, the below-described particular control operation of the present embodiment is executed.
Firstly, in step S15, the paper width detection sensors 118a, 118b and the paper length detection sensors 119a through 119c in
Herein, the controller 68 functions as second control means for controlling the stepping motor 34 of the supply range varying means illustrated in
Specifically, once the width dimension M of the paper 2 is detected, the controller 68 computes and determines a varnish coating area length H in accordance with the width dimension M of the paper 2, leaving a predetermined margin h1 from both left and right ends of the paper 2, as in
The varnish coating area length H may also be set on the basis of an instruction/setting from the operation panel 90 illustrated in
The controller 68 drives the stepping motor 34 to rotate the lead screw 33 and adjust thereby the spacing of the partition plates 32a, 32b so as to obtain the numerical width dimensions inputted via the numerical keypad 93.
As illustrated in
Upon detection that the varnish coating unit 20 is mounted, the controller 68 functions as a fifth control means for controlling the solenoid 88, as a pressure range varying means, in such a manner so as to change the range of pressure exerted by the press roller 9 onto the printed paper 2 in accordance with the paper transport direction size detected by the paper length detection sensors 119a through 119c (sheet transport direction size detection means) (step S17).
The varnish coating area L may also be set on the basis of an instruction/setting from the operation panel 90 illustrated in
A supplementary explanation follows herein, with reference to
Next, the process moves onto step S18. When a required number of varnish coat sheets is registered/inputted via the numerical keypad 93, and the print start key 94 is pressed, similarly as explained with reference to
When the unit discrimination sensor 37 detects that the varnish coating unit 20 is mounted, the controller 68 functions as third control means for controlling a power supply that supplies power to the heating coil heater 29 of the air blowing fan 11 in such a manner that the air blown between the coating roller 8 and the printed paper 2 that is fed after varnish coating is turned into hot blown air by turning the heating coil heater 29 on.
By blowing thus hot air onto the varnish on the surface of the printed paper 2 (printed product), the viscosity of the varnish is lowered, and the surface thereof is leveled by air pressure. The varnish surface can become smooth and sufficiently glossy as a result.
When the unit discrimination sensor 37 detects that the varnish coating unit 20 is mounted, the controller 68 functions, in addition to the above control, as a fourth control means for controlling the solenoid 88 of the pressing force varying means in such a manner that the pressing force exerted by the press roller 9 is comparatively smaller than when the drum unit 40 is mounted. This is done in the same way as explained with reference to
The varnish coating step is explained next with reference to
Within the coating area 103, a predetermined thickness of varnish is printed/coated onto a print image, which imparts the print image with glossiness, while enhancing the durability, wetting resistance and scratch resistance (abrasion resistance) of the print image. The visual quality or the printed product improves thereby, which adds value to the product.
Next, the varnish-coated printed paper 2 (printed product), which is released from the coating roller 8 by the air separation pawl 10 and the air blowing fan 11, is transported to the UV-radiating device 51 by the paper output transport device 12, and is further transported by the printed product transport device 52. The varnish-coated printed paper 2 is irradiated with direct UV rays from the UV-ray lamps 59 and with UV rays reflected by the reflective plate 60. The varnish on the varnish-coated surface of the printed product becomes cured and fixed thereby, after which the paper is stacked, neatly aligned, on the paper output tray 62. All the operation steps by the varnish coating device 39 terminate once the set number of sheets of the printed paper 2 (printed product) are coated with varnish (step S20 to step S22). From the above it follows that the constitution, action, operation and so forth of the present embodiment afford the effects set forth in the section on the effect of the invention.
As described above, the present invention allows realizing and providing a coating device and a coating unit in a novel stencil printing apparatus that solves the above-described problems of conventional art. The effects afforded by the present invention are enumerated below.
(1) A coating unit, for coating a predetermined area of the surface of a fed printed sheet (hereinafter referred to also as sheet-like “printed product” in the present section) with a given thickness of a viscous coating liquid, is configured to be detachably mounted on a printing apparatus main body in place of a printing drum unit. As a result, the printed product can be imparted a stylish feel, as well as storability and abrasion resistance, by coating a predetermined range (predetermined area) of the printed product with a uniform thickness of a viscous coating liquid (for instance, a UV-curable varnish liquid), in an inexpensive, simple and convenient way, employing an ordinarily used stencil printing apparatus that anyone can operate.
(2) The coating unit comprises a coating member for coating the surface of a printed sheet with a coating liquid; a supply device for forming a liquid pool, where the coating liquid accumulates temporarily, on the coating member, and for supplying a predetermined thickness of the coating liquid to the surface of the coating member; a holding member for holding a coating liquid storage container that contains the coating liquid; and a pump device for feeding the coating liquid from the coating liquid storage container to the liquid pool. Accordingly, the technology of the printing portion of a stencil printing apparatus can be effectively appropriated, using a simple structure and relying on a compact and inexpensive configuration. The amount of coating liquid, moreover, is maintained automatically, which results in an easier operation.
(3) In the above configuration, a first control means controls a supply range varying means in such a way so as to achieve a coating liquid supply length set by a setting means. As a result, the coating liquid (for instance, a UV-curable varnish liquid) can be reliably applied within only an appropriate range, while problems caused by overflow of excessive coating liquid can be prevented, thereby allowing the coating liquid to be applied in a required amount over a required area.
(4) In the above configuration, a second control means controls the supply range varying means in such a way so as to change the coating liquid supply length in accordance with the sheet width direction size of a printed sheet as detected by a sheet width size detection means. As a result, coating liquid can be appropriately applied automatically over a predetermined area in accordance with the sheet width direction size, and coating liquid overflow can be prevented by way of a simple operation, without the need for an operator or user (hereinafter “user”) to instruct/set the coating area of the coating liquid (for instance, a UV-curable varnish liquid) every time.
(5) In the above configuration, a third control means controls an air-blast release means in such a way so as to turn, into hot blown air, air that is blown between the coating member and the fed printed sheet after coating, when a unit discrimination means detects that the coating unit is mounted. As a result, the viscosity of the coated coating liquid (for instance, a UV-curable varnish liquid) decreases on account of the higher temperature. This affords a surface leveling effect that increases surface smoothness and allows imparting a glossy finish to the printed product.
(6) In the above configuration, a fourth control means controls a pressing force varying means in such a manner that, when the unit discrimination means detects that the coating unit is mounted, a pressing force is smaller than when the printing drum unit is mounted. As a result, the pressing force exerted is the minimum required for coating the coating liquid (for instance, a UV-curable varnish liquid). In addition to reducing noise, this allows preventing the problem that arises when the printed product wraps onto the coating member on account of excessive pressing force, and the problem of coating liquid overflow at both sides of the printed product on account of excessive pressing force.
(7) A fifth control means changes the pressure range of a pressing member in the sheet transport direction in accordance with a sheet transport direction size of the printed sheet as detected by a sheet transport direction size detection means, when the unit discrimination means detects that the coating unit is mounted. As a result, coating liquid can be appropriately applied automatically onto a predetermined area in accordance with the sheet transport direction size of the printed sheet, without the need for the user to instruct/set the coating area of the coating liquid (for instance, a UV-curable varnish liquid) every time, while preventing the problem of contamination of the pressing member caused by supply of coating liquid to portions other than the sheet transport direction size of the printed sheet. Also, coating liquid overflow can be prevented by way of a simple operation.
(8) A sixth control means changes the pressure range of the pressing member in the sheet transport direction in accordance with the sheet transport direction size of the printed sheet as set by a sheet transport direction size setting means, when the unit discrimination sensor detects that the coating unit is mounted. As a result, coating liquid can be appropriately applied automatically onto a predetermined area in accordance with the coating area of the coating liquid (for instance, UV-curable varnish liquid) instructed/set by the user, while preventing the problem of contamination of the pressing member caused by supply of coating liquid to portions other than the sheet transport direction size of the printed sheet. Also, coating liquid overflow can be prevented by way of a simple operation.
(9) A seventh control means performs control in such a way so as to permit inputs and operations when a stencil printing mode is selected and set by a mode selecting and setting means and the unit type detection means detects that the printing drum unit is mounted, and so as to permit inputs and operations when a coating liquid coating mode is selected and set by the mode selecting and setting means and the unit type detection means detects that the coating unit is mounted. As a result, this allows proactively preventing problems derived from a mismatch between the mounted unit and the instructed and selected/set mode, and allows issuing a warning to the user when the wrong unit is mounted.
(10) An eighth control means permits execution of a platemaking operation and a plate feeding operation when the unit type detection means detects that the printing drum unit is mounted, and start is set by a start setting means, and disables (prohibits) execution of a platemaking operation and a plate feeding operation when the unit type detection means detects that the coating unit is mounted, even when start is set by the start setting means. This allows preventing problems from occurring in a platemaking section, and/or wasting of a master in a platemaking operation, as a result of accidental pressing of the start setting means, even with the coating unit being mounted at that time.
(11) The above configuration allows curing and fixing instantly, through irradiation of UV rays, the UV-curable varnish liquid applied onto the surface of the printed product, so that the printed product, imparted thereby with a stylish feel, can be immediately manipulated, without further modification, in a subsequent process.
(12) In the above configuration, the coating unit that is mounted in place of the printing drum unit applies a given thickness of viscous coating liquid over a predetermined area of the surface of the printed sheet. A coating unit can be realized and provided as a result wherein the printed product can be imparted a stylish feel, as well as storability and abrasion resistance, by coating a predetermined range (predetermined area) of the printed product with a uniform thickness of a viscous coating liquid (for instance, a UV-curable varnish liquid), in an inexpensive, simple and convenient way, employing an ordinarily used stencil printing apparatus that anyone can operate.
(13) A coating unit can be realized and provided wherein the coating unit comprises a coating member for coating the surface of a printed sheet with a coating liquid; a supply device for forming a liquid pool, where the coating liquid accumulates temporarily, on the coating member, and for supplying a predetermined thickness of the coating liquid to the surface of the coating member; a holding member for holding a coating liquid storage container that contains the coating liquid; and a pump device for feeding the coating liquid from the coating liquid storage container to the liquid pool. Accordingly, the technology of the printing portion of a stencil printing apparatus can be effectively appropriated, using a simple structure and relying on a compact and inexpensive configuration. The amount of coating liquid, moreover, is maintained automatically, which results in an easier operation.
Various modifications will become possible for those skilled in the art after receiving the teachings of the present disclosure without departing from the scope thereof.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2007-193641 | Jul 2007 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4050409 | Duchenaud et al. | Sep 1977 | A |
| 6382093 | Hara | May 2002 | B1 |
| 7207269 | Yoshida | Apr 2007 | B2 |
| 20070089623 | Hamamoto et al. | Apr 2007 | A1 |
| Number | Date | Country |
|---|---|---|
| 2003-266909 | Sep 2003 | JP |
| 2003-312914 | Nov 2003 | JP |
| 2004-313829 | Nov 2004 | JP |
| 2006-35816 | Feb 2006 | JP |
| 2006-76080 | Mar 2006 | JP |
| 2006-281711 | Oct 2006 | JP |
| 2007-111873 | May 2007 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20090025580 A1 | Jan 2009 | US |
