Printing system and cassette printed by said system

Abstract: A printing method comprising forming a base layer by applying ink from a first ink jet type printing head vertically to the surface of a recording medium or a cassette accommodating the recording medium, forming a color print layer on the base layer by applying ink from a second ink jet type printing head, to which image information to be printed is supplied, in the vertical direction to the surface of the cassette, and forming a protective layer by applying ink from a third ink jet type printing head vertically to the print layer on the surface of the cassette.

Description: TECHNICAL FIELD This invention relates to a printing system for full-color printing on a printing object, such as paper, plastics or cassettes. The system may comprise a container vessel for containing printing objects. More particularly, it relates to a printing system for a printing object having irregularities on its outer surface. BACKGROUND ART In a cassette having housed therein an optical disc or a magneto-optical disc, or a tape cassette having housed therein a magnetic tape, printing is made of logo-marks asserting that the product is manufactured by a certain and certain company, or a variety of design patterns added for increasing the commercial value. For making a printing on these cassettes or the like, the following procedure is employed using offset printing or screen printing as the printing method. An original or manuscript on which a design to be printed on a cassette is drawn is color-separated by a color scanner. Each color positive film is prepared depending on the color separation and a master is prepared for each color. After calibration for each master, test printing is made on a cassette for adjusting the ink viscosity. Printing is then made after registration of the respective color masters. Meanwhile, the majority of the above-mentioned printing processes are carried out by a manual operation by experienced operators. Consequently, fluctuations tend to be produced in picture patten matching of white colors for solid printing, three prime colors, sepia or top coats, ink color modulation or ink viscosity adjustment. Besides, difficulties are presented in the master exchange or master registration operations for color matching, while plural printing objects cannot be printed collectively. Since the masters need to be produced to suit the respective colors, production costs are unavoidably raised. On the other hand, the cassettes are usually produced by injection molding of synthetic resin. Consequently, warps, bends or sinks are produced, although to a limited extent, due to contraction caused by cooling proper to the resin during injection molding, thereby worsening the planarity of the printing surface of the cassette. Above all, with the solid full surface printing of the planar portion of the cassette, slight warping, bending or irregularities produce contact shortage with a transfer roll resulting in color fluctuations, color dropout or color blurring, thereby lowering the printing quality. It may be contemplated to raise the printing transfer pressure for improving the contact of the transfer roll with the cassette. However, if the transfer pressure is raised, the rubber layer of the transfer rubber roll layer is distorted to cause distortion in the printed picture or letters. In addition, the negative or letter tends to be contaminated due to the elevated transfer pressure at the time of resetting of the deformed cassette, thereby markedly lowering the printing quality or causing cracks or printing interruptions depending on the type of the cassette material. Thus the printing may be made only on the planar portions of the cassette. Recently, a proposal has been made for employing an ink jet type printing head for printing on the cassette. With this proposal, a horizontal injection type ink jet printing head is used for injecting the ink in the horizontal direction because the casing for housing the printing object therein is contaminated by ink dripping with the commercial ink jet for sealing. With this printing head, a printing object 101 is transported in the vertical direction by a transport unit mainly consisting of an electric motor 103 and the ink is jetted forth onto the transported printing object in the horizontal direction as shown in Fig.1. The printing object 101 shown herein is tape-shaped. Meanwhile, the standard size cassette has a planar portion, a recessed area for labelling, a convexed area, chamfered curved or inclined portions or the like, with the warping during molding with synthetic resin or the molding tolerances being set to ±0.3 mm. Consequently, the difference between the recessed and convexed surfaces on the cassette surface is 3 mm, so that, when printing is made on the cassette surface, the optimum gap length, or a gap g between the cassette 101 and a printing head 102, is 2 to 4 mm. However, with the printing head 102 of the horizontal jetting type system, if the gap length g is set to 2 to 4 mm, the trajectory of the jetted ink particles describes a dropping curve so that the landing position is lower than a pre-set landing position. This produces distortions in the picture pattern to deteriorate the printing quality. Consequently, the gap length g from the printing object 101 at the time of single-color or multi-color printing on the printing object 101 has to be set so as to be less than 0.5 mm, because of the above-mentioned characteristics of the ink jet, so that printing may be made only on planar portions in case of printing of the cassette having surface irregularities, while printing cannot be made on the remaining areas, such as the recessed surfaces for labelling, convexed surfaces, R-surfaces or inclined surfaces. EP-A-0 036 296 discloses a system for applying two or more substances to a surface (e.g. of a container) wherein one of the substances is applied as a coating and another as a predetermined pattern by projecting droplets thereof onto the coating. JP-U-03 057 235 discloses a method of producing an ink jet printed panel (e.g. tiles of ceramics and cement, etc. and panels of glass, metal and wood, etc.) wherein an emulsion-type coating layer is coated on the panel; images or characters are ink jet printed on said layer followed by coating with a transparent cured plastic coating layer. It is therefore an object of the present invention to eliminate the above-mentioned technical difficulties and to provide a printing system whereby the mastering, ink color or ink viscosity adjustment is unnecessary and high quality printing may be made from the outset without the necessity of test printing. It is another object of the present invention to provide a printing system whereby the gap length between the printing object and the printing head may be selected to be broader to permit printing to be made on the surface of the printing object irrespective of whether or not the surface is planar. It is a further object of the present invention to provide a vessel for housing therein the printing object whereby printing may be made on a plurality of the printing objects simultaneously to improve the productivity significantly. It is yet another object of the present invention to provide a printing system whereby printing may be made irrespective of differences in the hardness of the cassette and continuous printing may be made from the planar area up to the recessed or convexed area, inclined area or curved area of the printing object. DISCLOSURE OF THE INVENTION The above-mentioned objects are obtained according to the invention by a printing system comprising: picture information outputting means for outputting the picture information for printing on a printing object, picture processing means for processing output signals of said picture information outputting means in a pre-set manner for printing, printing means having a non-contact printing head supplied with an output signal from said picture processing means, said printing means effecting printing on the printing object by said printing head, and transporting means for transporting the printing object, characterised in that said printing means comprises first printing means for forming an underlying layer on the printing object by printing, second printing means for effecting colour printing on said underlying layer formed by said first printing means on the printing object by said printing head supplied with an output signal from said picture processing means for forming a printed layer, and third printing means for forming a protective layer by printing on the printed layer formed by said second printing means. According to a particular aspect of the invention, said transporting means transports the printing objects by a container vessel adapted for holding a plurality of said printing objects in position therein. Said container vessel for a printing object comprises positioning means for being engaged with recesses of said printing object for positioning the printing object, said container vessel being adapted for transporting a plurality of the printing objects contained therein. According to a particular embodiment of the invention the printing system for printing on a recording medium or on a cassette having the recording medium housed therein is characterised in that it comprises: a first ink-jet printing head for ejecting the ink on the surface of the recording medium or of the cassette having the recording medium housed therein in a direction at right angles to said surface for forming an underlying layer, a second ink-jet printing head supplied with data based on the printing picture information on said surface for ejecting the ink in a direction at right angles to the surface for forming a colour printing layer on said underlying layer, and a third printing head for ejecting the ink on said printing layer in a direction at right angles to the surface for forming a protective layer. The invention further relates to a printing system for printing on a recording medium or a cassette, characterised in that it comprises: a first ink-jet printing head for ejecting the ink in a perpendicular direction on the surfaces of plural cassettes for forming an underlying layer, said cassettes being housed within a container vessel by being positioned by positioning means provided in said container vessel, said printing head being moved in the arraying direction of the cassettes housed within said container vessel, a second ink-jet printing head supplied with data based on the printing picture information for ejecting the ink in a perpendicular direction on the cassette surface for forming a colour printing layer on said underlying layer, said printing head being moved in the arraying direction of the cassettes in said container vessel, and a third ink-jet printing head moved in the arraying direction of the cassettes in said container vessel for ejecting the ink in a perpendicular direction on the cassette surface for forming a protective layer on said colour printed layer. According to another aspect of the invention a cassette to be used as a printing object in a printing system according to the invention is characterised in that said cassette comprises: a cassette main member having recessed and convexed areas on its surface and having a recording medium housed therein, an underlying layer formed continuously between the upstanding wall sections of the recessed and convexed areas of the cassette main member and the bottom surfaces of said recessed areas or the top surface of said convexed areas, a printed layer formed by colour printing based on the picture information to be recorded on said underlying layer, and a protective layer formed on said printed layer. With the printing system according to the present invention, the signals read by an image reader are transformed into a pre-set picture and the resulting information transformed into the picture is supplied to a non-contact type printing head. Alternatively, the replay signals reproduced from the recording medium on which the picture information has been recorded are processed for conversion into a pre-set picture, and the information thus converted into the picture is supplied to the contact-free printing head for printing on the printing object. Consequently, the respective color masters hitherto employed are transformed into picture outputs, as a result of which the laborious operation of mastering, registration of the respective color masters, ink color modulation or ink viscosity adjustment, may be eliminated to improve productivity and reduce the costs. On the other hand, since the output is the picture information, high-quality printing may be achieved from the outset without the necessity of test printing. Besides, since the printing head is not contacted with the printing object, high-quality printing may be achieved even if the printing object has defects such as warping, bending or irregularities. Consequently, color fluctuations, color extinction or blurred letter edges is not produced. In particular, since the perpendicular ejection type ink-jet printing head is employed as the non-contact printing head, the so-called drop curve is not delineated by the flight trajectory of the ink particles. Consequently, if the printing head 8 is fixed relative to the cassette 14, the image or picture such as picture patterns or letters may be printed satisfactorily on the printing surface of the cassette 14, inclusive of the planar surface, recessed surface for labels, convexed surface, R-surface or the inclined surface. On the other hand, with the printing device according to the present invention, since the non-contact printing head is adapted for controlling the height of the printing object based on the detection output of the detection unit for detecting surface irregularities of the printing object, printing may be made on the printing object maintained at the constant height despite warping, bending or irregularities on the surface of the printing object. Consequently, printing may be made continuously from the planar surface onto the recessed surface, convexed surface, inclined surface or curved surface without producing color fluctuations, color extinction or blurred letter edges. Besides, since detection means are provided in the non-contact printing head for detecting irregularities on the printing object, it is possible to control the height of the printing head relative to the printing object depending on the state of irregularities on the printing object. In addition, since a plurality of the printing objects may be held in position in the container vessel printing may be made on a plurality of the printing objects simultaneously. With the printing system according to the present invention, since the picture information is processed in a pre-set manner for conversion into pre-set pictures and printing is made on the cassette surface by the non-contact printing head based on the information thus converted into pictures, high-quality printing may be achieved even if the printing object has defects such as warping, bending or irregularities, while no external pressure is applied to the cassette. BRIEF DESCRIPTION OF THE DRAWINGS Fig.1 is a schematic perspective view showing an example of printing by a conventional ink-jet printing head of the horizontal jet type. Fig.2 is a schematic side view showing a drop-curve phenomenon of the trajectory of ink particles which represents an inconvenience in the conventional horizontal jet type ink-jet printing head. Fig.3 is a perspective view showing the printing system in its entirety. Fig.4 is an enlarged perspective view showing a full-color printing section. Fig.5 is a perspective view showing a printing head part of the full-color printing section. Fig.6 is a flow chart for illustrating the operation of the full-color printing section. Fig.7 is an enlarged partial perspective view showing a printing head provided with a profiling sensor. Fig.8 is an enlarged partial side view showing the state of printing by the printing head provided with the profiling sensor. Fig.9 is an enlarged partial perspective view showing a printing head provided with a laser displacement sensor. Fig.10 is an enlarged partial side view showing the state of printing by the printing head provided with the laser displacement sensor. Fig.11 is an enlarged partial side view showing the state of printing by the printing head provided with a plurality of laser displacement sensors. Fig.12 is a side view showing the state of printing on a video cassette by the printing head provided with the profiling sensor. Fig.13 is a side view showing the state of printing on a tape cassette by the printing head provided with the profiling sensor. Fig.14 is a side view showing the state of printing on a disc by the printing head provided with the laser displacement sensor. Fig.15 is a perspective view showing the state of printing on a profiled printing object by the printing head provided with the laser displacement sensor. Fig.16 is a cross-sectional view showing the state in which white solid printing and full-color printing are made on a profiled printing object. Fig.17 is a perspective view showing the state of printing on a gear by a printing head provided with the displacement sensor. Fig.18 is an exploded perspective view showing the constitution of a transport section. Fig.19 is a perspective view showing a handling section. Fig.20 is a perspective view showing a container vessel employed for clamping paper sheets. Fig.21 is a side view showing a container vessel employed for clamping paper sheets. Fig.22 is a perspective view showing a container vessel employed for clamping a cassette. Fig.23 is a side view showing a container vessel employed for clamping a cassette. Fig.24 is a perspective view showing an example of positively positioning a cassette in the container vessel by providing a positioning pin in a tray main member. Fig.25 is a perspective view showing a container vessel employed for clamping a sheet of plastics. Fig.26 is a perspective view showing a container vessel employed for clamping a disc. Fig.27 is a side view showing a container vessel employed for clamping a disc. Fig.28 is a perspective view showing an example of positively positioning a disc in the container vessel by providing a positioning pin in a tray main member. Fig.29 is a perspective view showing a container vessel in which a sheet of plastics is attracted under vacuum by a plurality of suction holes formed in the tray main member. Fig.30 is a cross-sectional view showing a container vessel in which a sheet of plastics is attracted under vacuum by a plurality of suction holes formed in the tray main member. Fig.31 is a perspective view showing a container vessel in which movable clamps are provided at diagonal portions of the tray main member. BEST MODE FOR CARRYING OUT THE INVENTION Referring to the drawings, preferred embodiments of the present invention will be explained in detail. In the present embodiment, the present invention is applied to a printing system in which full-color printing is made on a designated portion of a printing object. With the printing system of the present embodiment, so-called white solid coating is made on a plurality of cassettes by way of surface preparation, full-color printing is then made with three prime colors and ultimately a protective film is formed by way of top coating. The present printing system is made up of a supply section 1 for printing objects into which plural cassettes are charged, a solid printing section 2 in which white solid printing is made, a printing section 3 for full-color printing is made, and a printing section 4 in which top coating is made, as shown in Fig.3. With the present printing system, the printing section 2 for making white solid printing, the printing section 3 for full-color printing and the printing section 4 for top coating are essentially similar in constitution. Of these sections, the printing section 3 for full-color printing is crucial. Consequently, the following description is made of the printing section 3. The printing section 3 for full-color printing is made up of an image reader unit 6, an image processing unit 7, a printing head 8 and a transporting unit 10, as shown in Fig.4. The image reader 6 reads the picture information of a design manuscript 5. The image processing unit 7 transforms the signals as read by the image reader unit 6 into a pre-set picture. The printing head 8 is a non-contact printing head operated by the information transformed in a pre-set manner into pictures by the image processing unit 7. The transporting unit 10 transports a container vessel 9, having plural cassettes housed therein, in synchronism with the printing head 8, by an output signal from the image processing unit 7. The image reader unit 6 includes a scanner 11 having picture reading elements, such as color CCDs. By this scanner 11, the picture information of a design original or manuscript 5, on which pre-designed color patterns are drawn, is read, and color-separated from one pixel to another into R, G and B. As the design manuscript 5, an 8-pattern picture design drawn on an A-4 format copy paper sheet is employed, if printing is made on a video cassette having a tape with a tape width of 8 mm housed therein. As the manuscript 5, a 16-pattern picture design drawn on an A-4 format copy paper sheet is employed, if printing is made on a small-sized magneto-optical disc having a diameter of 64 mm. The picture patterns are drawn on the design manuscript 5 in a number corresponding to the number of the cassettes printed simultaneously. The image reader unit 6 reads the picture information drawn on the manuscript 5 by moving the scanner 11 along the length of the design manuscript 5. Meanwhile, the design pattern may be directly drawn by graphic designing using a word processor or a computer 12. Alternatively, the pre-designed picture information or the picture information may be stored on a magnetic disk cartridge 13, such as a floppy disk. If the design pattern is drawn by graphic designing by the computer 12, the picture information is directly outputted on the image processing unit 7 from the computer 12. If, on the other hand, the picture information is stored on the magnetic disk cartridge 13, the magnetic disk cartridge 13 is introduced into the magnetic disk drive provided in the computer 12 for reading out the information stored in the magnetic disk cartridge 13. The information stored in the magnetic disk cartridge 13 is reproduced and outputted at the computer 12 and subsequently outputted at the image processing unit 7. This obviates the necessity of preparing the design manuscript 5 to reduce the reading time significantly. The R, G and B color manuscript digital signals, color-separated from pixel to pixel by the image reader unit 6, are color-separated by the image processing unit 7 for R, G and B, and the color-separated printing data is stored in the memory of the image processing unit 7. The image processing unit 7 reads the color-separated digital signals fro the memory, which are outputted to the printing head 8 as later explained. The image processing unit 7 outputs an operating signal to the transporting unit 10 in synchronism with the movement of the printing head 8. The printing head 8 is a so-called vertical jet type ink-jet printing head for printing a cassette 14 lying directly below the printing head 8 in a non-contact manner by jetting the ink downwards from the distal end of e.g. a fine nozzle. The printing head 8 performs full-color printing on designated portions of the cassette responsive to the color-separated digital signals outputted by the image processing unit 7. The printing head 8 is mounted on a head actuating unit 15 adapted for moving the printing head 8 in the vertical direction and in the left-and-right direction with respect to the plural cassettes 14 contained in the container vessel 9, as shown in Fig.5. As a result thereof, the ink is ejected from the distal end of the nozzle provided in a head unit 16 of the printing head 8 for performing full-color printing on the designated portions of the cassette 14. The distance between the nozzle surface of the printing head 8 and the label area of the cassette, which is the planar surface destined for printing, is selected to be approximately equal to 5 mm. To the printing head 8, there are connected ink pipes 18 drawn out of respective ink tanks 17 having the three prime color inks of cyan, magenta and yellow and sepia as black color. The ink pipes 18 drawn out of the respective ink tanks 17 are connected to nozzles provided in the head unit 16 of the printing head 8. The ink tanks 17 are connected to the image processing unit 7 and are driven in operation responsive to the color-separated digital signals or the printing data supplied from the memory of the image processing unit 7 for supplying the inks to the respective nozzles. Since the printing head 8 is of the vertical ink-jet type of ejecting the inks in the vertical direction, the trajectory of the ink particles does not describe a drop curve, so that, even if the printing head 8 is secured to the cassette 14, printing of pictures or letters on the surfaces of the cassettes 14, in other words, the planar cassette surface, recessed surface for labelling, convexed surface, R-surface or the inclined surface, may be achieved satisfactorily. In the present embodiment, a unit is provided for shifting the printing head 8 in the vertical direction along the surface of the cassette 14 for improving the printing quality of the picture printed on the cassette 14. This unit is made up of the printing head actuating unit 15 and a shape detection unit for detecting the recesses or crests on the cassette 14 as later explained. The shape detection unit is provided in the printing head 8 and, as shown for example in Figs.7 and 8, includes a pair of profiling sensors 21, 22 having contactors 19, 20, adapted for being contacted with the surface of the cassette 14, respectively. These profiling sensors 21, 22 are secured to the head unit 16 in a row with respect to the travelling direction of the cassette 14, with the distal ends of the contactors 19, 20 being projected from the ink jet surface of the head unit 16. The contactors 19, 20 are adapted for omnidirectional detection, for an angular extent of 360°, and are adapted for being contacted with the surface of the cassette 14 for transmitting analog detection signals conforming to the recesses and crests of the cassette surface to a system controller which will be explained subsequently. The printing head actuating unit 15 is actuated under instructions from the system controller on the basis of the detection signals from the contactors 19, 20 for controlling the position along the height of the printing head 8. In this manner, the distance of the printing head 8 from the cassette 14 may be maintained constant at all times irrespective of whether the surface is planar, recessed, convexed, inclined or curved. This enables continuous high-quality printing from the planar surface to the convexed or recessed surface, inclined surface or a curved surface in a manner free from color fluctuations, color extinction or blurred letter edges. Besides, since the printing head 8 is not contacted with the cassette 14, printing may be made in a finished state without the necessity of applying an external pressure to the cassette 14. As the shape detection device for detecting surface irregularities of the cassette 14, any of the laser displacement sensor, ultrasonic sensor or the photo-electric sensor, may be employed. Taking an example of the laser displacement sensor, four laser displacement sensors 23 to 26 are secured in a row along the travel direction of the cassette 14, as shown in Figs.9 and 10. By so doing, digital detection signals corresponding to the surface irregularities of the cassette 14 may be outputted from the laser displacement sensors 23 to 26. By outputting detection signals from the displacement sensors 23 to 26 to the system controller, the printing head actuating unit 15 is actuated under commands from the system controller based on the detection output for controlling the printing head position along its height. It is also possible to provide the laser displacement sensors 23 to 26 for the printing heads 8a, 8b, 8c and 8d for the respective colors, respectively, and independently control the positions of the printing heads 8a to 8d along the height thereof relative to the cassette 14 based on the detection signals from the laser displacement sensors 23 to 26, as shown in Fig.11. By providing the shape detection device in the printing head 8 for detecting the surface irregularities of the printing object, high-quality printing may be made for any shape of the printing object and irrespective of whether the printing object is hard or soft. For example, if the printing object is a video tape-cassette 27 having an 8-mm tape housed therein, printing may be made continuously from a curved surface 28a of a lid 28 onto a recessed surface 27a and a planar surface 27b of the cassette main member, as the position of the printing head 8 along its height relative to the video tape cassette 27 is controlled by the profiling sensor 21, as shown in Fig.12. Similarly, if the printing object is an audio cassette 29, printing may be made continuously from a recessed surface 29a onto a planar surface 29b of the cassette main member, as the position of the printing head 8 along its height relative to the audio cassette 29 is controlled by the profiling sensors 21, 22, as shown in Fig.13. On the other hand, if the printing object is a disc-shaped object, such as an optical disc or a magneto-optical disc, printing may be made continuously from a planar recording surface 30a of a disc 30 onto a recessed and convexed surface 32a of a disc hub 32, as the position along the height of the printing head 8 relative to the disc 30 is controlled by a non-contact sensor 31, such as an ultrasonic sensor or a photoelectric sensor, as shown in Fig.14. If the printing object is a profiled sheet of plastics having a curved surface 33a, a recessed and convexed surface 33b and an inclined surface 33c mixed together, as shown in Figs.15 and 16, printing is made in the following manner. The position of the printing head 8 along its height relative to a plastic sheet 33 is controlled by a non-contact sensor 34 of the type employing an ultrasonic sensor or a photo-electric sensor, and printing is made continuously from the curved surface 33a onto the recessed and convexed surface 33b and the inclined surface 33c of the sheet 33 by the printing head 8. Meanwhile, a letter A is printed with the example shown in Figs.15 and 16. If the printing object is a gear 35 as shown in Fig.17, printing is made continuously on a carved surface 35a of each tooth of the gear 35 by the printing head 8 as the position of the printing head 8 along its height relative to the gear 35 is controlled by a non-contact sensor 36 of the type employing the ultrasonic sensor or the photoelectric sensor. On the other hand, the transporting unit 10 is responsive to an actuating output signal from the image processing unit 7 to transport the container vessel 9, having plural cassettes 14 housed therein, in synchronism with the scanning of the printing head 8. The purpose of synchronizing the transport of the container vessel 9 with the scanning of the printing head 8 is to enable high quality printing. The transport unit 10 includes feed sections 38, 39 for transporting the container vessels 9 along a pair of transport rails 36, 37 mounted parallel to and at a pre-set distance from each other as shown in Fig.18. The feed sections include a pair of feed rails 40, 41 mounted below and parallel to the transport rails 36, 37 and a pair of sliders 42, 43 slidably mounted on the feed rails 40, 41. The sliders 42, 43 are provided with tray feed hooks 46, 47, respectively, engaged in feed hook holes 44, 45 formed in the container vessels 9, respectively. These tray hooks are provided for performing a vertical reciprocating movement with respect to the sliders 42, 43, respectively. That is, the tray feed hooks 46, 47 are protruded from the sliders, 42, 43 for being engaged with the hook holes 44, 45 for feeding the container vessels 9 to the top coat printing section 4 of the next stop, respectively, while being receded from the sliders 42, 43 otherwise, respectively. The feed sections 38, 39, constituted as described above, are controlled by a sequencer 48 and a controller 49. When the container vessel 9, having housed therein the cassettes 14 from the preceding white solid printing process, is fed as far as the full-color printing section 3, the hook 46 of the slider 42 of the feed section 38 is protruded into engagement with the associated feed hook hole 44. The container vessel 9 is fed in synchronism with the scanning of the printing head 8. After the termination of the full-color printing, the container vessel 9 is fed to the top coat printing section 4 of the next step. During this time interval, the remaining feed section 39 is adapted for being returned from the position to which the feed section has fed the container vessel 9 as far as the printing section 4, at a speed higher than the feed speed during printing, to an initial position, in which the container vessel 9 is positioned in readiness for the next printing. During this movement, the tray feed hook 47 is receded from the associated slider 43. Consequently, by the alternate feed operations by the two feed sections 38, 39, the container vessels 9, having housed therein the cassettes 14, on which the solid white printing has been completed, may be continuously transported without interruptions as far as the top coating printing section 4 of the next step. The transport unit 10 is provided with stop devices 50, 51 for halting the container vessels 9 at a pre-set position. These stop devices 50, 51 include paired slide rails 52, 53; 54, 55 mounted on either sides of the transport rails 36, 37 at right angles to the transport rails 36, 37, and paired positioning members 56, 57; 58, 59 slid on these slide rails 52, 53; 54, 55 for positioning the container vessels 9, respectively. The positioning members 56, 57; 58, 59 are slid on the slide rails 52, 53; 54, 55, respectively, into abutment with the corners of the container vessels 9 for regulating the position of the container vessels 9. The stop devices 50, 51 include a portion of positioning the container vessels 9 transported from the white solid printing section 2 to the full-color printing section 3 at the full-color printing position and a top coat printing portion for top coat printing at the printing section 4 of the next step. The operation at the above-described full-color printing section 3 is performed in accordance with the flow chart shown in Fig.6. First, the design manuscript 5, on which a pre-designed color picture pattern is drawn, is read by the scanner 11, and the thus read picture information is color-separated on the pixel basis. Alternatively, the picture information as graphically designed by a word processor or the computer 12 is directly outputted at the image processing unit 7. Still alternatively, the image information or the picture information stored in the magnetic disk cartridge 13 is directly outputted at the image processing unit 7. The color manuscript digital signals, color-separated on the pixel basis, are color-separated for R, G and B by the image processing unit 7 and stored in a memory within the image processing unit 7. The color-separated digital signals, as printing data, are read from the memory and outputted to the printing head 8, at the same time as an actuating signal is issued for actuating the transporting unit 10 for transporting the container vessels 9 having the cassettes 14 housed therein. At this time, the printing head 8, head actuating unit 15 and the transport unit 10 are controlled by a system controller 62 made up of a pair of control boxes 60, 61 connected to the image processing unit 7 as shown in Fig.5 so that the container vessels 9 are fed in synchronism with the movement of the printing head 8. A detection output is also issued at this time from the profiling sensors 21, 22 provided in the printing head 8 to the system controller 62. With the output signal of the system controller 62, the head actuating unit 15 is controlled so that the distance of the printing head 8 relative to the cassette 14 is maintained at a constant value. Then, under the controlled state, the each color ink is selected and ejected from the distal end of the nozzle provided in the printing head 8 for performing full-color printing on the cassette 14, based on the image information from the scanner 11. Ultimately the printed surface is finished by the pressure roll 63 to complete the printing. The solid printing section 2 for solid white printing is constituted similarly to the printing section 3. That is, the image or picture information stored in the magnetic disk cartridge 13 is directly outputted to the computer 12, the information from which is outputted to the memory of the image processing unit 7. White solid printing is made by the printing head 8 on the cassettes 14, based on the output signals read from the memory of the image processing unit 7, as the non-contact printing head 8 and the container vessels 9 are operated in synchronism with each other under control by the system controller 62. The white solid printing is performed by way of surface preparation for full-color printing of the next step. For the whiter solid printing, the ink composed of the white-colored pigment containing high-density anchoring agents, for example, is applied on the cassette 14 as the printing object, by way of printing. Since the cassette 14 itself is of the grayish to black color, it is necessary to perform white solid printing about four times in consideration of light emitting performance for color printing. The picture information includes a shell window producing patterns if the printing object is the cassette 14. The white solid printing section 2 includes, above all, a handling unit 64 for transporting the container vessels 9, having housed therein the cassettes 14 to be supplied to the supply section 1, as far as the printing section 2. The handling unit 64 includes a handling portion 65 for sucking the container vessel 9 under vacuum, as shown in Fig.19. The handling portion 65 is adapted to be moved along a first rail 66 in a direction shown by an arrow X in Fig.19 and along a second rail 67 at right angles to the first rail 66 in a direction shown by an arrow Z in Fig.19. The handling portion 65 is adapted for performing a three-dimensional movement in the directions shown by arrows X, Y and Z in Fig.17 under control by a controlling section made up of a sequencer 69 and a controller 70. Thus the container vessels 9, supplied to the supply section 1, are handled and transported to the printing section 2 by the moving operation by the handling portion 65. Meanwhile, the operation by the handling portion 65 is performed by a remote control unit 71 connected to the controller 70. The top coat printing section 4 is constituted similarly to the printing section 3. That is, the image or picture information stored in the magnetic disk cartridge 13 is directly outputted to the computer 12, the information of which is outputted to the memory of the image processing unit 7. The non-contact printing head 8 and the container vessels 9 are operated in synchronism with each other, based on the output signals as read from the memory of the image processing unit 7, under control by the system controller 62, for applying top coat printing on the cassettes 14. The top coat printing is an processing operation of forming a transparent protective film for improving characteristics of the full-color printed picture design, such as resistance to alcohol or scratch proofness. The supply section 1 for printing objects is adapted for laying in stock a large number of the dedicated container vessels 9 having arrayed therein a plurality of cassettes 14 from the molding process. Each container vessel 9 is designed for holding a plurality of, herein 12 cassettes 14, such as video cassettes, therein. Each of the cassettes includes a tray main member 72 of a A-4 format copy sheet size, having housed therein a tape having a tape width of 8 mm, with the cassettes 14 being clamped together by a pair of clamps 73, 74, as shown in Figs.22 and 23. These clamps 73, 74 are rotatably mounted along both lateral edges of the tray member 72 and include key-shaped end retainers 75, 76 for retaining the printing surfaces of the cassettes 14. The clamps 73, 74 are perpetually biased by torsion springs, not shown, in a direction of retaining the cassettes 14. The tray main member 72 is provided with a transport engaging section 77 comprised of feed hook through-holes 44, 45 engaged by the tray feed hooks 46, 47 of the transport unit 10. For assuring reliable loading of the cassettes 14 on the container vessels 9, positioning pins 80, 81 engaged in through-holes 78, 79 for reel hubs may be set on the tray main member 72 in register with the through-holes 78, 79 for the reel hubs, formed in the cassette 14, as shown for example in Fig.24. Meanwhile, when full-color printing a paper sheet 83, such as a thin paper sheet or a carton board, the container vessel 9 as shown in Figs. 20 and 21 is employed. With such container vessel 9, the clamps 73, 74 movable by a torsion spring are provided on both lateral edges of the tray main member 72, and a fixed clamp 82 included a plate spring is provided at a mid part of the tray main member 72. These clamps 73, 74 and the fixed clamp 82 are provided with retainers 84, 85 and 86 for clamping the paper sheets 83, respectively. It is possible with the container vessel 9 to retain the paper sheet having the size or thickness outside of the standard values. For full-color printing a plastic sheet 87, the container vessel 9 for containing the cassettes 14 is used in combination with the plastic sheets 87, as shown in Fig.25. For assuring reliable loading of the plastic sheets 87 on the container vessel 9, plural vacuum suction holes 91 may be formed in the tray main member 72 and the inside of the tray main member is evacuated via these vacuum holes 91 for holding the cassettes 14 by the tray main member 72 under vacuum, as shown in Figs.29 and 30. A vacuum hose 92 may be led out of one lateral surface of the tray main member 72. For securing the plastic sheets 87 to the container vessel 9, the diagonal portions of the container vessel 9 may be provided with L-shaped movable clamps 93, 94 which may be moved by springs, as shown in Fig.31, and by means of which the plastic sheets may be fixed in position. For full-color printing on a disc-shaped printing object 88, such as the optical object or the magneto-optical disc, the container vessel 9 for housing the cassettes 14 therein as described above may be employed, and the disc 88 may be arrayed as shown in Figs.25 and 26. For positively loading the disc 88 in the container vessel 9, a positioning pin 90 may be set at a point on the tray main member 72 in register with a center opening 89 formed in the disc 88, as shown for example in Fig.28. With the above-described printing system, the white solid printing, full-color printing and top coat printing are performed consecutively in the following manner. First, plural cassettes 14 from the molding process are arrayed on the container vessel 9 and clamped. A large number of container vessels 9 in stock are handled from the supply section 1 and transported to the printing section 2 for white solid printing. In the printing section 2, white solid printing is performed in a contact-free manner at the designated areas of the cassettes 14 on the basis of the image information or the picture information from the magnetic disk cartridge 13, outputted from the computer 12, so that the scanning of the printing head 8 is synchronized with the feed movement of the container vessels 9. After the end of the white solid printing, the container vessels 9 are fed by the transport unit 10 to the printing section 3 of the next step. In the printing section 3, full-color printing is performed in a contact-free manner on designated portions of the cassettes 14, on the basis of the picture information read by the scanner 11, so that the scanning of the printing head 8 is synchronized with the feed movement of the container vessels 9. After the end of the white solid printing, the container vessels 9 are transported by the transporting unit 10 to the printing section 4 of the ultimate step. In the printing section 4, a top coat layer is formed in the full-color printed areas of the cassettes, on the basis of the image or picture information from the magnetic disk cartridge 13, outputted from the computer 12, in a contact-free manner, so that the scanning of the printing head 8 is synchronized with the fed movement of the container vessel 9. Ultimately, the printed surface is finished by the pressure roll 63 to complete the printing. If the profiled plastic sheet 33 is taken as an example of the printed object, a white solid layer 95 is formed on the curved surface 33a, recessed and convexed surface 33b and the inclined surface 33c, a full-color printed letter 96 or the like is formed on the solid layer and a top coat layer, not shown, is formed on the letter 96 and the white solid layer 95, as shown in Fig.16. The same may be said of the cassette 14, herein not shown, in which case full-color printed letters 96 are formed on the solid layer 95 and a top coat layer is formed on the letter 96 and the solid layer 95. INDUSTRIAL APPLICABILITY It is seen from above that, with the printing system according to the present invention, signals read from the image reader are transformed into a pre-set picture and the information transformed into the picture is supplied to a non-contact printing head, or alternatively, the replay signals reproduced from a recording medium on which the picture information is recorded are transformed into picture signals which are supplied to the non-contact printing head to effect printing on the printing object. Consequently, printing may be made directly on the printing object with the printing head on the basis of the output picture information. Consequently, the laborious operation of mastering, master exchange, color master registration, ink color or ink viscosity adjustment, which has so far been necessary, may be eliminated to improve productivity and production yield significantly. Besides, since the printing head is not contacted with the printing object, printing may be made on both the hard printing object and on the soft printing object without applying an external pressure on the printing object. Besides, since the picture is outputted, color balance may be automatically achieved by digital duplication, while the numeric processing is enabled to simplify the printing significantly. On the other hand, since the perpendicular ejection type ink-jet printing head is employed as the non-contact printing head, a so-called drop curve is not delineated by the trajectory of ink particles, so that, even if the printing head is secured to the printing object, printing of picture patterns or letters may be made satisfactorily on the surface of the printing object, such as the planar surface, recessed surface for labelling, convexed surface, R-surface or the inclined surface. On the other hand, with the printing device according to the present invention, since the non-contact printing head has its height relative to the printing object controlled on the basis of a detection output from the detection means detecting the recesses or troughs of the printing object, printing may be made at all times with the correct distance between the printing head and the printing object, such that printing may be made continuously from the planar area onto the recessed surface, convexed surface, inclined surface, curved surface, elliptical area or the polygonal area, without producing color fluctuations, color extinction or blurred letter edges, despite the presence of warping, bends or irregularities on the printed object. Besides, since detection means is provided in the non-contact printing head for detecting irregularities of the printing object, the printing head height may be perpetually maintained constant relative to the printing object depending on the detected irregularities. Consequently, the ink film thickness may be transformed into numerical values to assure high quality printing. In addition, a plurality of printing objects may be held in position by the container vessel so that printing may be made on a number of printing objects simultaneously. Different color picture patterns delineated on the design manuscript 5 may be read by the color CCD scanner and printed by a non-contact printing head using such container vessel to allow different picture patterns to be printed on plural printing objects so that small quantity multiple variety printing or simultaneous printing of different designs may be performed efficiently.

Claims: A printing system comprising: picture information outputting means (6; 12) for outputting the picture information for printing on a printing object (14, 27; 29; 32; 33; 35; 87; 88), picture processing means (7) for processing output signals of said picture information outputting means (6) in a pre-set manner for printing, printing means having a non-contact printing head (8) supplied with an output signal from said picture processing means (7), said printing means effecting printing on the printing object by said printing head (8), and transporting means (10) for transporting the printing object, wherein said printing means comprises first printing means (2) for forming an underlying layer on the printing object by printing, second printing means (3) for effecting colour printing on said underlying layer formed by said first printing means (2) on the printing object by said printing head (8) supplied with an output signal from said picture processing means (7) for forming a printed layer, and third printing means (4) for forming a protective layer by printing on the printed layer formed by said second printing means (3). The printing system as claimed in claim 1, characterised in that said picture information outputting means (6; 12) is an image reader (6) for reading the picture information recorded on a manuscript (5). The printing system as claimed in claim 1, characterised in that said picture information outputting means is a reproducing device (12) having reproducing means for reproducing a recording medium (13) on which the picture information is recorded. The printing system as claimed in claim 1, characterised in that said printing means further comprises scanning means for scanning the printing head (8) and wherein the printing system further comprises control means for effecting synchronised driving control of said scanning means and said transporting means (10). The printing system as claimed in claim 1, characterised in that said printing means further comprises detection means for detecting irregularities of the printing object. The printing system as claimed in claim 5, further comprising control means for controlling the position of the printing head on the printing object based on the results of detection from said detection means. The printing system as claimed in claim 1, characterised in that said transporting means (10) transports the printing objects by a container vessel (9) adapted for holding a plurality of said printing objects in position therein. The printing system as claimed in claim 5, characterised in that said detection means comprises a contactor (19, 20) contacting with the surface of the printing object. The printing system as claimed in claim 5, characterised in that said detection means comprises a plurality of laser displacement sensors (23-26). A printing system according to claim 7, characterised in that said container vessel (9) for a printing object comprises positioning means (80, 81; 90) for being engaged with recesses (78, 79; 89) of said printing object (14; 88) for positioning the printing object, said container vessel (9) being adapted for transporting a plurality of the printing objects contained therein. A printing system according to claim 1, for printing on a recording medium or on a cassette having the recording medium housed therein, characterised in that it comprises: a first ink-jet printing head for ejecting the ink on the surface of the recording medium or of the cassette having the recording medium housed therein in a direction at right angles to said surface for forming an underlying layer, a second ink-jet printing head supplied with data based on the printing picture information on said surface for ejecting the ink in a direction at right angles to the surface for forming a colour printing layer on said underlying layer, and a third printing head for ejecting the ink on said printing layer in a direction at right angles to the surface for forming a protective layer. A cassette having layers printed by a printing system according to claim 1, characterised in that said cassette comprises: a cassette main member having recessed and convexed areas on its surface and having a recording medium housed therein, an underlying layer formed continuously between the upstanding wall sections of the recessed and convexed areas of the cassette main member and the bottom surfaces of said recessed areas or the top surface of said convexed areas, a printed layer formed by colour printing based on the picture information to be recorded on said underlying layer, and a protective layer formed on said printed layer. A printing system according to claim 1 for printing on a recording medium or a cassette, characterised in that it comprises: a first ink-jet printing head for ejecting the ink in a perpendicular direction on the surfaces of plural cassettes for forming an underlying layer, said cassettes being housed within a container vessel (9) by being positioned by positioning means provided in said container vessel, said printing head being moved in the arraying direction of the cassettes housed within said container vessel, a second ink-jet printing head supplied with data based on the printing picture information for ejecting the ink in a perpendicular direction on the cassette surface for forming a colour printing layer on said underlying layer, said printing head being moved in the arraying direction of the cassettes in said container vessel, and a third ink-jet printing head moved in the arraying direction of the cassettes in said container vessel for ejecting the ink in a perpendicular direction on the cassette surface for forming a protective layer on said colour printed layer.

Inventors: KANO KENICHI, KANO, KENICHI, KANO, KENICHI, C/O SONY CORPORATION
Applicants: SONY CORP, SONY CORPORATION
Application year: 1993
Main classification: B41J2
IPC codes: G11B23, B41J2, B41J3, B41J5, B41J29, H04N1, B41J11