04/708002

01/05/1971

02/26/1968

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Nippon Enlarging Color Inc. (Tokyo, JA)

358/502

358/501

H04N1/034; H04N1/50; H04N1/032; H04N9/02

178/5.2

Murray, Richard

Leibowitz B.

I claim

1. A method of enlarged multicolor printing, comprising scanning a color original by a single camera means capable of performing color separation, converting color information thus scanned into printing signals corresponding to the separated colors, separately controlling a plurality of spaced-apart color-printing heads each for a different color by corresponding different signals of said color-printing signals, moving said printing heads and a medium to be printed relative to each other in synchronism with the original scanning and with said printing heads in substantial alignment along a single printing scan path, providing a time delay for the printing signals of each color after the signals for the first printing head, said time delays corresponding to the relative traveling time of the relevent spaced printing head for each color and correspondence therewith of a picture element on the medium to be printed after the first head thereat and continuously providing said printing signals to all printing heads for concurrently controlling printing by all heads, and applying color material from the spaced-printing heads to the medium to be printed according to said control by said printing signals so as to reproduce an enlarged color picture having substantially the density of each particular color at the corresponding picture element of the color original.

2. A method of enlarged multicolor printing as defined in claim 1 wherein the scanning by a camera of a color original is done with relative movements therebetween in two directions substantially at right angles, and said applying of color material from the printing heads to the medium to be printed is done with the relative movements therebetween in synchronism with said scanning movements and with a greater printing surface scan movement than the original scan surface movement with a correspondingly enlarged printed picture element area over the original scanned picture element area.

3. A device for enlarged multicolor printing, comprising a single camera means capable of scanning a color original and performing color separation into primary color light, means for converting primary color light beams from said camera means into electric signals, color-printing heads each for the application of a different one of the primary colors, driving means for driving both said printing heads and said medium to be printed relative to each other to provide a printing scanning of said medium by said heads in synchronism with the scanning of the original and with a greater printing surface scan movement than the original scan surface movement with a correspondingly enlarged printed picture element area over the corresponding original scanned picture element area, said printing heads being spaced from each other in substantial alignment along a single printing scan path and being constructed to print said enlarged printed picture element area, means providing for utilizing said converted primary color light beam electric signals for continuously controlling operation of said printing heads, time delay means for delaying respective electric signals by a period corresponding to the time for the respective color-printing heads and the medium to be printed to travel relative to each other through the scan interval defined by the spacing between the respective color-printing heads and the first of said printing heads relative to the medium to be printed while continuously controlling the operation of said heads whereby coloring material is applied from said spaced printing heads to the medium to be printed maintaining registration of each color and so as to reproduce the density of each color at the corresponding picture element of the original.

4. A device for multicolor printing as defined in claim 3 including a drive roll means for mounting the color original for scanning by said camera, said driving means for driving the medium to be printed including a roll for mounting the medium and having a relatively greater diameter than said color original mounting roll driven synchronously therewith whereby a correspondingly greater printing surface scan movement than the original scan surface movement is provided, and said printing heads are spaced in substantial lateral alignment substantially perpendicular to the axis of rotation of the medium to be printed mounting roll.

5. A device for multicolor printing as defined in claim 4 having a light quantity detecting means on said camera means for detecting the light quantity at and in the vicinity of each picture element scanned, and a light quantity controlling means for regulating the light quantity in the camera means in response to the output of said light quantity detecting means.

6. A device for multicolor printing as defined in claim 3 wherein said means for converting primary color light beams from said camera into electric signals comprises photoelectric means, and said device includes means for converting said electric signals for primary color into corresponding printing color signals and includes means for combining said primary color signals for providing a printing signal for the color black.

7. A device for enlarged multicolor printing as defined in claim 6 having a light quantity detecting means mounted on said camera means for detecting the light quantity at and in the vicinity of each picture element being scanned, and a light quantity controlling means for regulating the light quantity in the camera means in response to the output of said light quantity detecting means.

8. A device as defined in claim 3 wherein each printing head comprises a needle valve having a tube of rigid material, the tip end of the tube being made of resilient material, an opening in said valve for passage of color material, and means for introducing compressed air into the tube to swell and contract the tip end so as to effect control of the size of the opening by control of the compressed air pressure.

9. A device as defined in claim 3 wherein each color printing head comprises a color material nozzle having a needle valve provided with a pair of longitudinal grooves, and a solenoid arranged to rotate the needle valve to control the position of the grooves and regulate the discharge of the color material.

10. A device as defined in claim 3 wherein each printing head comprises a needle valve having a rigid tube with a tip end formed of resilient material, an opening in said valve for passage of color material therethrough, and means for introducing pressurized liquid into said resilient tip end for controlling the size thereof and thereby the size of said opening.

This invention relates to an improvement in a method for enlarged mutlicolor printing and a device therefor.

What is meant by the "device for enlarged multicolor printing" is such device which produces extremely enlarged multicolor printed copies (to be referred to as "prints," hereinafter) directly from a natural color original copy (to be referred to as "original," hereinafter) of small size, such as a color film or a color print.

The principle of the method according to the present invention is based on a novel technical idea, which is entirely different from that of known photography, chemical printing process, or electronic printing techniques. In the method of the invention, information concerning the original picture, as collected by scanning, is converted into electric signals representing physiological three primary colors, which are then amplified and evaluated for converting again into different electric signals representing four primary colors of printing. The electric signals thus prepared are transferred to printing heads to control the feeding of four primary color inks onto a medium to be printed, such as a white paper, so as to produce a desired enlarged multicolor print.

According to a salient feature of the present invention, the process of forming enlarged multicolor prints can be accomplished by a single scanning operation of the original

For a better understanding of the invention, reference is made to the accompanying drawings, in which:

FIG. 1 is a schematic perspective view, illustrating operative principles of a monochromatic enlarging device;

FIG. 2 is a diagrammatic illustration, showing schematically operative principles of a multicolor enlarging device;

FIG. 3 is a simplified perspective view of an embodiment of the device according to the present invention;

FIG. 4 is a block diagram, showing the setup of a device for enlarged multicolor printing, according to the present invention;

FIGS. 5a and 5b are schematic illustrations, respectively showing a color patch applied to an original and a monitor indicating the output of the corresponding to the color patch;

FIGS. 6 to 11 are diagrammatic illustrations, showing different optical systems usable in a scanner;

FIGS. 12 and 13 are schematic diagrams, illustrating two different spray gun systems associated with paper feeding systems, efficiently applicable in a device according to the present invention;

FIG. 14 is a diagrammatic illustration, showing another embodiment of the invention using a magnetic recording tape;

FIGS. 15 and 16 are schematic sectional views of solenoid valves usable in the device according to the present invention; and

FIGS. 17 to 23 are schematic diagrams, showing spray gun nozzles usable in the device according to the present invention.

Referring to FIG. 1, illustrating the operative principles of the device according to the present invention, the process of producing an enlarged print of a monochromatic original, will be described at first. The device comprises a small cylinder 1 and a large cylinder 2, which is similar in shape to the small cylinder 1. An original is mounted around the periphery of the small cylinder 1, while a white paper is mounted on the large cylinder 2. Rails 5 and 6 are disposed relatively parallel with the axes of the cylinders 1 and 2, respectively, while carriers 7 and 8 are slidably mounted on the rails 5 and 6. The carrier 8 is adapted to move in proportion to the movement of the other carrier 7.

The carrier 7 has a photoelectronic detecting means consisting of a light source 9, lens means 10, a filter 11, and a photocell 12, which detects the density of a specific color at a particular point of the original. The carrier 8 has a spray gun 13 disposed against the surface of the cylinder 2 with a distance of several centimeters. Compressed air is supplied to the spray gun through a solenoid valve 14, so as to spray the pigments in a pigment tank 13' onto a printing medium, a white paper 4. The solenoid valve should be capable of varying the degree of valve opening very frequently with ease.

In the device as illustrated in FIG. 1, the distance between the tip end of the spray gun and the surface of the cylinder 2 is settled in a considerably short distance, and hence, the pigment ejected from the spray gun is not scattered but acts to color the white paper in a spot of several millimeters in diameter. When the aforesaid detecting means senses the density of a particular color at a certain point on the original 3, information on the color density thus sensed is transferred to the solenoid valve 14 through an electric link a to modify the degree of valve opening accordingly, and hence, the flow rate of compressed air to the spray gun is regulated accordingly. Thus, the rate of pigment discharge out of the spray gun is modified and hence, a particular point on the white paper, which corresponds in position to the certain point on the original can be painted in the specific color, in the same density as that of the specific color at the certain point on the original Thus, as the large and small cylinders rotate in synchronism, the carriers move along each cylinder to scan every point on the surface of each cylinder by the spray gun and the detecting means, respectively. Thereby, an enlarged print of the original mounted on the small cylinder can be made on the white paper mounted on the large cylinder.

The inventor has noticed the fact that the diameter of a spot painted by a spray gun is in the order of several millimeters and succeeded in applying such fact to enlargement of an original. If the diameter of each minimum element constituting the original is one one-hundredths to one-tenth mm., then the rate of enlargement will be several ten or several hundred, because each such minimum element of the original is enlarged to a printed spot of several millimeters diameter.

FIG. 2 shows a device for producing an enlarged multicolor print by carrying out the aforesaid process in a plurality of primary colors. A plurality of suitably spaced detecting means 15, 16, 17, and 18, which are the same in number as the colors to be detected, are associated with a small cylinder 1 having an original mounted thereon. Each detecting means has a color filter 15', 16', 17', or 18', respectively, to detect only that color which is allocated to the specific detecting means. A plurality of spray guns 19, 20, 21, and 22 are associated with a large cylinder 2 having a white paper mounted thereon, in a similar manner to the aforesaid detecting means associated with the small cylinder, and each spray gun is provided with a solenoid valve 19', 20', 21', or 22', respectively. The detecting means 15 is electrically coupled to operate the solenoid valve 19' of the spray gun 19, so that the spray gun 19 can print the white paper in a particular color allocated thereto, in accordance with the density of the color in the original, as sensed by the detecting means 15. Similarly, the other spray gun 20 paints the white paper in another color allotted thereto, in accordance with the density of the color in the original, as sensed by the detecting means 16. The remaining spray guns paint the white paper in the similar manner, but in different colors allotted thereto, respectively. Thus, an enlarged multicolor print of an original can be produced by a single scanning operation of the entire original.

An object of the present invention is to improve such multicolor printing device by providing an easily operable and economically producible multicolor printing device.

With the preceding example of enlarged multicolor printing devices, as described in detail referring to FIGS. 1 and 2, it is necessary to use a pair of a photoelectronic detecting means to scan the original and a painting head to scan a white paper, associated to each other in 1 to 1 relation, for detecting and printing each color. If enlargement in four primary colors of printing is desired four sets of such detecting means are necessary. Accordingly, the prior device set forth as above for enlarged multicolor printing has the following difficulties; namely, that the device is complexed in construction and requires high accuracy, that the operation of the device is complicated, for instance, when a small cylinder for mounting an original is replaced with another small cylinder having a different diameter, the optical systems of photoelectronic detecting means must be refocussed; and that originals smaller than certain predetermined dimensions can hardly be enlarged or reproduced, because it is very difficult not only to mount a plurality of detecting means, e.g. four detectors, on the periphery of a small original, but also to pick up corresponding four points accurately both on the original and on he white paper by registering them vertically and horizontally.

In an improved device according to the present invention, only one optical system is used to pick up information on different colors in one step from a particular point of the original, which information is converted into signals representing primary colors, and each color signal thus prepared is delayed in order to match the relative position of printing heads and the white paper. Thereby, the same effect as that of the four optical systems mounted aside the small cylinder for originals, as shown in FIG. 2, can be achieved by using only one optical system.

The salient features of the device according to the present invention are as follows.

The device is simple in construction and can be made in compact form, because it has only one optical system.

Interchange among small cylinders of different diameters to hold originals can be achieved with ease, because only one adjustment of the focus is sufficient for each interchange.

Adjustment of printing heads on a white paper held by a large cylinder is simplified, by indexing them only in lateral direction of the paper.

Only a small number of photoelectronic transducer elements to be mounted in the optical system of the detecting means are sufficient.

A magnetic recording means is used in the device of the invention to provide proper time delays to electric signals representing different printing colors.

Now, referring to FIG. 3, illustrating an embodiment of the present invention, a small cylinder, or an original holding cylinder 1, rotates in synchronism with a magnetic drum 23 and a large drum 2 by a suitable means, such as by directly connecting the cylinder 1 to the drum 23 and the cylinder 2 as illustrated by chain line. Light beams from a light source penetrate through an original 3 and proceed into a photohead PH, so that the light beams are separated into physiological three primary colors by dichroic mirrors 24, 24' and then converted into electric current signals having different magnitude by photoelectric transducer elements 25, 26, and 27. The electric signals representing the physiological three primary colors are fed to a color modifying circuit 28 to be modified into four primary colors of printing.

Each electric signal representing the four primary colors of printing is related to a particular point of the original, and hence, it is necessary to delay each such signal by a period corresponding to the travelling time of the printing medium relative to the printing heads 36, 37, 38, or 39, each of which is spaced apart a distance d between the adjacent printing heads. To achieve such time delay, the magnetic drum 23 has a recording head 29, a magenta reproducing head 30, a cyanic reproducing head 31, a black reproducing head 32, and an erasing head 33, each mounted on the periphery thereof. The arrangement of the reproducing heads on the magnetic drum corresponds to that of the printing heads 37, 38, and 39 on the surface of the large drum 2, and for instance, a central angle θ on the axis of the magnetic drum between the reproducing heads 31 and 32 is the same as the central angle on the axis of the large cylinder 2 between the printing heads 38 and 39.

Let it be assumed that a particular point on the original has color components representing all four primaries of printing, then a yellow signal activates a yellow printing head 36 through an output circuit 35, while three signals representing magenta, cyanic and black colors are fed to the magnetic recording head 29 to be stored therein temporarily. When the spot of the white paper thus printed in yellow arrives to the area beneath the magenta printing head 37, responsive to the rotation of the large cylinder 2, the magenta signal magnetically stored in the magnetic drum is picked up from the magenta reproducing head 30 to actuate the magenta printing head 37 through a reproducing amplifier circuit 34 and the output circuit 35. Similarly, the cyanic and black signals are picked up in succession, to activate the corresponding printing heads. The erasing head 33 resets the magnetic drum 23 after the aforesaid reproduction of color signals in each rotation thereof, so as to prepare the magnetic drum ready for the next delaying operation. A monitor circuit 40 indicates the wave form of each color signal on a cathode ray tube, to facilitate visual supervision thereof.

FIG. 4 is a block diagram, showing an example of electric circuitry usable in the device according to the present invention. Referring to the FIG., light beams issuing from a light source 9 are chopped about 3,000 times a second by means of a chopped 41, and then reflected by a mirror 42 driven by a mirror driving mechanism 43, so as to illuminate an original film 3 through a slit 44. A lens 45 is provided to produce a real image of the original at a pin hole 46, so that only those light beams which have passed through a particular point on the original 3 are subjected to color separation into three primary colors, i.e., blue, green, and red, by means of dichroic mirrors 24 and 24'. The light beams thus separated are delivered to color separating photomultiplier tubes 25, 26, and 27, respectively. A half mirror 47 and another pin hole 48 are disposed just in front of the pin hole 46 to constitute a light quantity detecting portion, so that the light beams through the aforesaid particular picture element being scanned on the original and the proximity thereof can be delivered to a light quantity controlling photomultiplier tube 49.

Picture elements on the original having different color densities are converted into 3 kc. electric signals and light quantity controlling signal by the aforesaid photomultiplier tubes, and the electric signals are fed to low frequency amplifiers 61, 62, 63, and 64 through band-pass filters 51, 52, 53, and 54, set at 1.5 to 4.5 kHz. respectively. Then, the signals are rectified by detector circuits 71, 72, 73, and 74, to produce DC signals. The signal for light quantity controlling is, thereafter, amplified by a DC amplifier 65 to energize the mirror driving means 43, so that the quantity of light passing through the slit 44 can be controlled by regulating the angular position of the mirror 42. Such light quantity controlling operation of the mirror 42 performs negative masking and unsharp masking effects. In other words, at the bright portion of the original, the light source is automatically darkened, while at the dark portion of the original, the light source is automatically brightened.

The DC signals thus produced for each primary color contain certain amount of unnecessary components for multicolor printing, and hence, suitable modification should be made on the signals to eliminate such unnecessary components. The DC signals for the three primary colors are then adjusted by masking circuits 81, 82, and 83 to produce modified signals for each color, and thus modified signals are added to the corresponding unmodified DC signals by adder circuits 84, 85, and 86, respectively, to produce printing three primary color signals, i.e. yellow, magenta, and cyanic signals. Since a fourth color, i.e. black, is necessary for printing, a black signal is synthesized from the three primary color signals by means of the black forming circuit 87.

Since the four color-printing signals thus synthesized tend to be compressed at the high density and low density portions thereof. Accordingly, highlight intensifying circuits 91, 92, 93, and 94 are provided to modify the four primary color signals. The printing primary color signals, except yellow signal, are subjected to waveform shaping at pulse duration modifying circuits 95, 96, and 97, to facilitate magnetic recording. The thus duration modified signals are then stored temporarily by recording heads 29, 29', and 29" until they are picked up by reproducing heads 30, 31, and 32 after a certain suitable delay time.

An erasing head 33 erases such recorded signals after the reproduction in each rotation of a magnetic drum to perform the delaying operation cyclically.

The pulse duration modified signals for magenta, cyanic, and black colors thus reproduced are converted into amplitude modified signals by transducers 102, 103, and 104. The DC signal for yellow is converted into a low frequency amplitude modified signal by another transducer 101. The amplitude modified signals thus prepared are then amplified by low frequency amplifiers 111, 112, 113, and 114, and then demodulated by detectors 121, 122, 123, and 124, respectively, to actuate printing heads 36, 37, 38, and 39, assigned to each printing primary colors.

It should be noted here that the four printing primary color signals include suitable time delays corresponding to the position of the respective printing heads, so that all the four primary color signals represent a common point of the original.

In order to supervise the gradation of the output color signals and other characteristics thereof, there is provided a monitoring circuit, which comprises a monitoring amplifier 131, a sweep oscillator 132, an output amplifier 133, and an afterglow type, or phosphorescent type, cathode-ray tube 134.

The function of the monitoring circuit is as follows. If a gray scale with a color path 135 is applied to the original 3 along an edge thereof, as shown in FIG. 5a, and if the output signals obtained by scanning the gray scale with the color patch 135 are applied to the vertical axis of the afterglow cathode-ray tube 134, while synchronizing the horizontal, or time, axis thereof with the rotation of the small cylinder 1, then an afterglow curve 136 representing the different shades of the gray scale and the degree of color separation can be produced on the cathode-ray tube 134.

In order to facilitate a still better understanding of the invention, construction of printing head, for printing and fixing the information carried by the output color signals in the form of pigment painted on the white paper in different color densities, will now be described referring to FIGS. 15 to 23. In the following description, such printing heads will be explained by referring to spray guns, which can be advantageously used in the enlarged multicolor printing device, according to the present invention.

In a solenoid valve, as depicted in FIG. 15, a pneumatic valve 154 integral with a moving coil 152 is mechanically connected to a diaphragm 153, which is in turn secured to a permanent magnet 151 and an upper shell 155. An inlet opening 156 receive compressed air to deliver it selectively to a spray gun through a valve port 157. By varying the magnitude of the signal current through the moving coil 152, the pneumatic valve 154 is reciprocated vertically, and accordingly, the flow rate of compressed air to the spray gun is changed so as to control the discharge rate of ink therefrom. The particular solenoid valve, as shown in FIG. 15, can operate as fast as 5,000 times a second.

FIG. 16 shows another solenoid valve usable in the device according to the present invention, which includes a bellows 163 integrally connected to a pneumatic valve 162 made of light metal at the lower end thereof and airtightly secured to the lower end of a valve body 164 at the upper end thereof. The valve body has an inlet opening 165 to receive compressed air and a valve port 166 to deliver the compressed air selectively to a spray gun. The lower end of the pneumatic valve 162 is connected to a spring 161 and a moving iron 160 associated with an exciting solenoid 159 mounted on a permanent magnet 158. The moving iron 160 shifts itself responsive to the variation of signal current through the exciting solenoid 159, and accordingly the pneumatic valve 162 reciprocates vertically. This valve can operate 1,000 times a second.

FIG. 17 shows a spray gun having a needle valve 167 enclosed by outer shell structures 168, 169. Compressed air is forced through an inlet opening 170 to spray ink out of a nozzle 173 through passages 171 and 172. The needle valve 167 is made of soft iron and placed in an electromagnet, consisting of iron core 174 and a solenoid 175. A coiled spring 176 is inserted between the iron core 174 and the needle valve 167. The needle valve 167 reciprocates longitudinally, responsive to variation of a current through the solenoid 175, to control the degree of opening of the nozzle 173, so as to regulate the discharge rate of ink therethrough. 16

In another spray gun, as shown in FIG. 18, a needle valve having a permanent magnet integrally mounted thereon is pivotally supported by a bearing 179. As shown in FIG. 19, the permanent magnet 178 faces an iron core 180 to be magnetized by a solenoid 181 in such a manner that upon energization of the solenoid 181, the needle valve 177 rotates against the elastic force of springs 182. The angular displacement of the needle valve 177 is determined by the balance between magnetic force acting thereon and the elastic force of the springs 182. Referring to FIGS. 20, 21a, and 21b, illustrating details of an ink nozzle 183, the needle valve 177 has a pair of longitudinal grooves 185, 185 bored at diagonally opposite portions of the tip end thereof, while a pair of corresponding grooves 185', 185' are bored on the diametrically opposite portions of the inner surface of outer shell structure 184. The relation among the permanent magnet 178, the springs 182, and the electromagnet consisting of the iron core 180 and the solenoid 181 is such that when a maximum current flows through the solenoid 181, the grooves 185, 185 of the needle valve fully face the corresponding grooves 185', 185' of the outer shell structure, as shown in FIG. 21a, to provide the maximum degree of nozzle opening. On the other hand, FIG. 21b illustrates the ink nozzle 183 in the state as fully closed. By regulating the degree of opening of the ink nozzle 183, responsive to the magnitude of the current through the solenoid 181, the ink discharge rate can be controlled in proportion to the magnitude of the current.

FIG. 22 shows another spray gun usable in the device according to the present invention, which comprises a needle valve having a metallic tube 186 and a tip end 187 made of resilient material, such as rubber. Compressed air is fed through a port 188, while ink is fed through another port 189. Pressurized oil or compressed air is fed through an opening 190, whose pressure varies in accordance with the magnitude of output signals from the aforesaid output circuit 35, to swell or contract the tip end 187. Accordingly, an ink nozzle 191 varies the degree of opening thereof. FIG. 23 shows a part view of the ink nozzle 191, in the state as open with the tip end 187 of the needle valve contracted.

The invention has been described by referring to an embodiment using a pair of cylinders to hold an original and a white paper, respectively, for simplicity. However, the invention is not restricted to the use of such cylinders, and a number of modifications of details of parts and arrangement thereof are possible without departing from the scope of the invention. For instance, the original 3 can be moved in two coordinate directions, while holding an optical system PH stationary together with a scanning camera associated therewith, as shown in FIG. 6. The scanning can be done by various methods: for example, by turning a small mirror M, which reflects illuminating light beams towards an original 3, as shown in FIG. 7; by sweeping an illuminated original 3 by turning a small mirror M, which reflects light beams from the original towards a scanning camera PH, as shown in FIG. 8; by moving a glass fiber tube GL at the back of an original 3, which tube leads light beams to the original, as shown in FIG. 9; by using a flying spot-type cathode-ray tube CT, whose luster is projected onto an original 3 through a suitable lens means LS, as shown in FIG. 10; or by using a point light source PL, instead of the last-mentioned flying spot-type cathode-ray tube, which light source is reciprocated by a belt or chain, while projecting light beams from the light source onto an original 3 through a suitable lens means LS, as shown in FIG. 11.

In the preceding description, a white paper is taken as a medium on which enlarged multicolor printing is made. However, various other media, such as a cloth, photosensitized paper, and the like, can also be used for enlarged multicolor printing, according to the present invention. Instead of mounting such medium on a cylinder for printing, various other printing methods can be used. For example, one or more printing heads 201 can be moved by rails 202 and guide rails 203 in coordinate directions above a flatly spread medium 204 to be printed, as shown in FIG. 12. A printing head 205 provided the nozzle 206 can be mounted on a revolving disc to print a medium 204 to be printed along arcuate loci, which medium is gradually drawn from a storage roller 207 and wound on a takeup roller 208 after the printing, as shown in FIG. 13. With such scanning system, it becomes unnecessary to wind an original on a cylinder, and hence, enlargement of a picture drawn on hard board, such as a metal plate or a wooden board, can readily be accomplished.

Furthermore, entire multicolor information of an original 3 can be stored in a suitable memory means 210, such as a magnetic tape, so that printing heads 211 can be actuated by reproducing the thus-stored information at any desired time, by using a suitable recording and reproducing system 212, for instance a system as shown in FIG. 14. With such recording and reproducing system, the process of scanning an original and storing the scanned information can be done in a very short period, and furthermore, the process of handling of the original and the process of enlarged multicolor printing can be performed separately. Hence, the overall efficiency of the process of producing enlarged multicolor prints from an original can be materially improved, by using such recording and reproducing system.

As described in the foregoing, according to the present invention, multicolor enlargement of an original copy can be accomplished with only one scanning stroke. The optical system to be used in the method of the invention can be very simple, because each color original, such as a color film, is scanned by using only one light source spot to produce corresponding electric signals. Accordingly, the adjustment of different color printings can be made very accurately.

By applying simple modification, the scanning and/or printing can be carried out with the original and/or the medium to be printed held in the state as flatly spread.

Salient features of the present invention can be summarized as follows.

Multicolor enlarged prints of considerably large size can be produced at a low cost.

Prints prepared by the method of the present invention are light fast, because pigments having excellent lightproofness can be used.

No special photosensitive paper is necessary, and the multicolor enlarged printing can be made on any ordinary paper or cloth.

Dark room is unnecessary for printing.

As compared with conventional enlarging method, the volume of printing shop can be reduced drastically, because the need of projecting an original is completely eliminated.

Various techniques for making printing plates, such as emphasis of color tone, emphasis of detailed contrast, neglect of letters, and the like, can be used on a medium to be printed.

Therefore, the method of multicolor printing according to the present invention has an extensive applicable fields, some of which are as follows.

Large color prints for outdoor advertisement.

Large color prints for display in business shows and various fairs.

Background pictures for setting color television scene.

Background pictures on stages of various plays, shows, musicals, etc.

Color prints for news or notice boards in schools and public places.

Decorative pictures to be placed on indoor and outdoor walls of buildings.

Etched enlarged relief on a metallic plate, prepared by using corrosive agents instead of pigments.

Zinc plate for offset printings, prepared by using suitable chemicals instead of pigments.

Enlarged multicolor printing of an original on various cloths.