Patent Publication Number: US-6213020-B1

Title: Drawing apparatus and drawing method

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a drawing apparatus and a drawing method of drawing an image on a plate mounted on an outer peripheral surface of a drum. 
     2. Description of the Background Art 
     Drawing apparatuses for drawing an image upon irradiation of a plate used for printing with light have been used. In a drum-type drawing apparatus, a plate is mounted on a recording drum which is rotatable in a primary scanning direction, and a recording head comprising a laser diode and the like is moved in a secondary scanning direction parallel to a rotary shaft of the recording drum, to draw an image on the plate. 
     FIG. 9 is a schematic perspective view of a recording drum in a conventional drawing apparatus. A plate  160  made of aluminum serving as a recording material is mounted on a recording drum  150  shown in FIG. 9. A front end clamp  170  for fixing one end of the plate  160  and a rear end clamp  180  for fixing the other end of the plate  160  are mounted on an outer peripheral surface of the recording drum  150 . The rear end clamp  180  contains a magnet, and is fixed by a magnetic force to a position, on the outer peripheral surface of the recording drum  150 , corresponding to the size of the plate  160 . 
     The recording drum  150  having the plate  160  attached thereto is rotated at relatively low speed around a rotary shaft  190 , so that an image is drawn on the surface of the plate  160 . 
     In the conventional drawing apparatus, positioning pins (not shown) for positioning the plate  160  are provided on the outer peripheral surface of the recording drum  150 . Positioning holes for a recording drum (hereinafter referred to as recording drum positioning holes) to be respectively fitted on the positioning pins are formed at one end of the plate  160 . In mounting the plate  160  on the recording drum  150 , the recording drum positioning holes of the plate  160  are respectively fitted on the positioning pins of the recording drum  150 . Accordingly, it is possible to accurately position the plate  160  on the outer peripheral surface of the recording drum  150 . 
     On the other hand, positioning pins for positioning the plate  160  are also provided on the body of a printing machine. The positions of the positioning pins differ depending on the specification of the printing machine. Therefore, in the plate  160 , positioning holes for a printing machine (hereinafter referred to as printing machine positioning holes) must be respectively formed in positions corresponding to the specification of the printing machine. 
     Generally after the image is drawn on the plate  160  by the drawing apparatus, the printing machine positioning holes are respectively formed in predetermined positions of the plate  160  on the basis of an end surface of the plate  160  using a punching machine. The plate  160  can be positioned on the body of the printing machine by respectively fitting the printing machine positioning holes formed in the plate  160  on the positioning pins of the printing machine. 
     However, the size of the plate  160  varies. When the printing machine positioning holes are formed on the basis of the end surface of the plate  160  after the image is drawn by the drawing apparatus, the relationship between the image formed on the plate  160  and the printing machine positioning holes varies. In this case, the shift in the position for printing must be corrected by shifting the plate  160  mounted on the body of the printing machine while seeing the results of the printing obtained by the printing machine using the plate  160 . Therefore, printing work becomes complicated. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a drawing apparatus capable of accurately positioning a plate in a printing machine irrespective of the variation in the size of the plate. 
     Another object of the present invention is to provide a drawing method in which a plate can be accurately positioned in a printing machine irrespective of the variation in the size of the plate. 
     A drawing apparatus for drawing an image on a plate used for a printing machine having a positioning portion according to one aspect of the present invention comprises a cylindrical drum having a rotary shaft, an outer peripheral surface on which the plate is mounted and a positioning portion provided on the outer peripheral surface, a driving device for rotating the drum around the rotary shaft, a drawing unit for drawing an image on the plate mounted on the outer peripheral surface of the drum, and a fitting portion forming device for forming in the plate a first fitting portion to be fitted to the positioning portion of the drum and a second fitting portion to be fitted to the positioning portion of the printing machine before the plate is mounted on the drum. 
     In the drawing apparatus, the positioning portion is provided on the outer peripheral surface of the drum. Before the plate is mounted on the drum, the first fitting portion to be fitted to the positioning portion of the drum and the second fitting portion to be fitted to the positioning portion of the printing machine are simultaneously formed in the plate by the fitting portion forming device. 
     Thereafter, the plate is mounted on the outer peripheral surface of the drum in a state where the first fitting portion of the plate is fitted to the positioning portion on the outer peripheral surface of the drum. It is possible to draw an image on the plate on the outer peripheral surface of the drum by the drawing unit while rotating the drum having the plate mounted thereon around the rotary shaft by the driving device. At the time of printing, the second fitting portion of the plate is fitted to the positioning portion of the printing machine, so that the printing is done using the plate. 
     The first fitting portion and the second fitting portion are thus simultaneously formed in the plate. The image is drawn by the drawing unit in a state where the first fitting portion of the plate is fitted to the positioning portion of the drum. Therefore, the relationship between the image formed on the plate and the second fitting portion can be kept constant irrespective of the variation in the size of the plate. Consequently, it is possible to accurately position the plate in the printing machine in doing the printing by the printing machine using the plate, so that the position of printing is not shifted. As a result, no work for correcting the shift in the position of printing is required, thereby improving the efficiency of the printing work. 
     The positioning portion of the drum may be a positioning pin, the positioning portion of the printing machine may be a positioning pin, the first fitting portion may be a first positioning hole to be fitted on the positioning pin of the drum, and the second fitting portion may be a second positioning hole to be fitted on the positioning pin of the printing machine. 
     In this case, when the plate is mounted on the drum, the plate can be positioned on the outer peripheral surface of the drum by fitting the first positioning hole of the plate on the positioning pin of the drum. When the printing is done, the plate can be accurately positioned in the printing machine by fitting the second positioning hole of the plate on the positioning pin of the printing machine. 
     The fitting portion forming device may comprise a plurality of punching units for forming the first and second positioning holes in the plate. 
     In this case, the first and second positioning holes are simultaneously formed in the plate by the plurality of punting units. Consequently, the relationship between the first positioning hole and the second positioning hole is kept constant, so that the relationship between the image formed on the plate and the second positioning hole is kept constant. 
     The fitting portion forming device may further comprise a supporting member disposed in a predetermined position, and a mounting member provided in the supporting member so as to be attachable or detachable and having the plurality of punching units carried thereon. 
     In this case, the mounting member having the plurality of punching units carried thereon is provided so as to be attachable or detachable in the supporting member. By preparing a plurality of mounting members corresponding to a plurality of types of plates and a plurality of types of printing machines and replacing the mounting member in conformity with the size of the plate and the specification of the printing machine, therefore, it is possible to simultaneously form the first and second positioning holes in suitable positions corresponding to the various types of plates and printing machines. 
     The supporting member may have a reference surface, and mounting member may have one end surface which is abutted against the reference surface of the supporting member. 
     In this case, the one end surface of the mounting member is abutted against the reference surface of the supporting member, thereby making it possible to accurately and easily position the mounting member on the supporting member. 
     The fitting portion forming device may further comprise a positioning mechanism for positining the plate in a predetermined position of the supporting member. 
     In this case, the plate can be put in the predetermined position of the supporting member by the positioning mechanism. Consequently, it is possible to accurately form the first and second positioning holes in predetermined positions of the plate. 
     The positioning mechanism may comprise a pair of abutting members provided so as to be abuttable against both the side surfaces of the plate upon being moved from on the both sides of the plate toward the center thereof, and an abutting member driving device for moving the pair of abutting members from on the both sides of the plate toward the center thereof. 
     In this case, the pair of abutting members is abutted against both the side surfaces of the plate upon being moved from on the both sides of the plate toward the center thereof by the abutting member driving device. Accordingly, the plate is put in the predetermined position while being moved in the width direction. 
     The fitting portion forming device may further comprise adsorbing and holding means for adsorbing and holding the plate on the supporting member. 
     In this case, the first and second positioning holes are formed in accurate positions of the plate by the plurality of punching units in a state where the plate is adsorbed and held on the supporting member by the adsorbing and holding means. 
     The drawing apparatus may further comprise selection means for selecting the plurality of punching units. 
     In this case, it is possible to provide the plurality of punching units corresponding to the plurality of types of plates and the plurality of types of printing machines, and to select the punching units conforming to the size of the plate and the specification of the printing machine by the selection means. Consequently, it is possible to simultaneously form the first and second positioning holes corresponding to the various types of plates and printing machines without replacing the punching units. 
     The drawing apparatus may further comprise a conveying unit for conveying the plate to the fitting portion forming device, and then conveying the plate to the drum. 
     In this case, the plate is conveyed to the fitting portion forming device by the conveying unit, and the plate having the first and second fitting portions formed therein is conveyed to the drum by the fitting portion forming device, so that the image is drawn by the drawing unit. 
     The conveying unit may further comprise a first conveying path for conveying the plate to the fitting portion forming device and the drum, and a swinging mechanism for swinging the first conveying path between the fitting portion forming device and the drum. 
     In this case, the first conveying path is swung toward the fitting portion forming device by the swinging mechanism, and the plate is conveyed to the fitting portion forming device through the first conveying path. After the first and second fitting portions are formed in the plate by the fitting portion forming device, the plate is then returned to the first conveying path. Thereafter, the first conveying path is swung toward the drum by the swinging mechanism, so that the plate is conveyed to the drum from the first conveying path. The plate is thus smoothly conveyed to the fitting portion forming device and the drum through the first conveying path. 
     The conveying unit may further comprise a second conveying path for conveying the plate removed from the drum. 
     In this case, the plate removed from the drum is conveyed through the second conveying path other than that in a case where the plate is conveyed to the fitting portion forming device and the drum. 
     A method of drawing an image on a plate which is used for a printing machine having a positioning portion and mounted on an outer peripheral surface of a cylindrical drum according to another aspect of the present invention, wherein the drum has a rotary shaft and a positioning portion provided on the outer peripheral surface, comprises the steps of forming in the plate a first fitting portion to be fitted to the positioning portion of the drum and a second fitting portion to be fitted to the positioning portion of the printing machine, mounting the plate having the first fitting portion and the second fitting portion formed therein on the outer peripheral surface of the drum, and drawing an image on the plate on the outer peripheral surface of the drum while rotating the drum around the rotary shaft. 
     The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic side view of a drawing apparatus in one embodiment of the present invention; 
     FIG. 2 is a schematic front view of the drawing apparatus shown in FIG. 1; 
     FIG. 3A is a plan view and 
     FIG. 3B is a front view of a punching device in the drawing apparatus shown in FIG. 1; 
     FIG. 4 is a plan view showing replacement of templates in the punching device shown in FIG. 3; 
     FIG. 5A is a plan view of a plate having recording drum positioning holes and printing machine positioning holes formed therein and 
     FIG. 5B is a plan view showing a state where the plate is positioned on an outer peripheral surface of a recording drum; 
     FIG. 6 is a side view showing the construction of a conveying unit in the drawing apparatus shown in FIG. 1; 
     FIG. 7 is a side view showing the operation of the conveying unit shown in FIG. 6; 
     FIG. 8 is a side view showing the operation of the conveying unit shown in FIG. 6; 
     FIG. 9 is a perspective view of a recording drum in a conventional drawing apparatus. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 is a schematic side view of a drawing apparatus in one embodiment of the present invention, and FIG. 2 is a schematic front view of the drawing apparatus shown in FIG.  1 . 
     In FIGS. 1 and 2, the drawing apparatus comprises a cylindrical recording drum  1 . The recording drum  1  is rotated in a direction indicted by an arrow A (a primary scanning direction) around a rotary shaft  1   a  by a rotation driving device  4 . A plate  100  made of aluminum is mounted as a recording material on an outer peripheral surface of the recording drum  1 . One end of the plate  100  is fixed to the outer peripheral surface of the recording drum  1  by a plurality of front end clamps  2 , and the other end of the plate  100  is fixed to the outer peripheral surface of the recording drum  1  by a plurality of rear end clamps  3 . 
     As shown in FIG. 2, a recording head  8  comprising a plurality of laser diodes  81  is disposed ahead of the recording drum  1 . The recording head  8  is attached to a guide  82  so as to be movable, and is moved in a direction indicated by an arrow B (a secondary scanning direction) in synchronization with the rotation of the recording drum  1 . 
     The plurality of laser diodes  81  in the recording head  8  are driven by a laser diode driving circuit portion  110 . The laser diode driving circuit portion  110  comprises a plurality of laser diode driving circuits  111  corresponding to the plurality of laser diodes  81  in the recording head  8 . 
     An image signal generator circuit  130  generates a serial image signal. A serial/parallel converter  120  converts the serial image signal generated by the image signal generator circuit  130  into parallel image signals, and respectively feeds the parallel image signals to the plurality of laser diode driving circuits  111  in the laser diode driving circuit portion  110 . Consequently, each of the laser diodes  81  in the recording head  8  is driven by the corresponding laser diode driving circuit  111 , to irradiate the plate  100  with laser light. 
     As shown in FIG. 1, a clamp driving device  5  is provided behind the recording drum  1 . The clamp driving device  5  is used for attaching the rear end clamps  3  to the recording drum  1 , detaching the rear end clamps  3  from the recording drum  1 , and releasing the front end clamps  2  on the recording drum  1 . 
     The clamp driving device  5  comprises a pair of clamp arms  6  which is swingable in a direction indicated by an arrow C. A driving bar  60  is mounted between the pair of clamp arms  6 , and a plurality of first driving devices  7  are attached to the driving bar  60 . As shown in FIG. 2, each first driving device  7  is provided with a driving pin  75  for fixing and releasing the rear end clamp  3 , two holding pins  76  for holding the rear end clamp  3 , and a release pin  78  for releasing the front end clamps  2  at the time of attaching the plate  100 . The clamp driving device  5  comprises second driving devices (not shown) for releasing the front end clamps  2  at the time of detaching the plate  100 . 
     As shown in FIG. 1, a conveying unit  9  is disposed so as to be swingable in a direction indicated by an arrow R above the recording drum  1 . The conveying unit  9  has a first plate carry-in conveying path  91  and a second plate carry-out conveying path  92 . When the plate  100  is carried into the recording drum  1 , the plate  100  is supplied onto the recording drum  1  through the first conveying path  91  in the conveying unit  9 . When the plate  100  is carried out of the recording drum  1 , the plate  100  which has been detached from the recording drum  1  is carried outward through the second conveying path  92  in the conveying unit  9 . 
     A punching device  10  for forming recording drum positioning holes and printing machine positioning holes in the plate  100  is disposed on the side of a front end of the conveying unit  9 . The plate  100  is supplied to the punching device  10  through the first conveying path  91  in the conveying unit  9  before being supplied onto the recording drum  1 . Accordingly, the recording drum positioning holes and the printing machine positioning holes are formed at a front end of the plate  100 . The recording drum positioning holes of the plate  100  are respectively engaged with positioning pins  15  provided on the outer peripheral surface of the recording drum  1 . 
     A controller  600  shown in FIG. 1 comprises a CPU (Central Processing Unit), an input-output interface, and so forth, and controls the respective units of the drawing apparatus. An operation panel  700  for a worker entering various types of information such as the size of the plate  100  and various types of instructions is connected to the controller  600 . 
     FIG. 3A is a plan view of the punching device  10 , and FIG. 3B is a front view of the punching device  10 . FIG. 4 is a plan view showing replacement of templates in the punching device  10 . 
     As shown in FIGS. 3A and 3B, the punching device  10  comprises a punching base  200 . Motors for moving the plate  100  in the width direction (hereinafter referred to as moving motors)  201  are respectively attached to both ends of a front surface of the punching base  200 . A pair of ball threads  204  extending in the horizontal direction along the front surface of the punching base  200  is provided so as to be rotatable. Each of the ball threads  204  is rotated by the moving motor  201 . 
     A bearing for moving the plate  100  in the width direction (hereinafter referred to as a moving bearing)  202  is meshed with each of the ball threads  204 . A cylindrical holder  203  is provided so as to be rotatable on the upper surface of each moving bearing  202 . The moving bearings  202  are moved in a direction indicated by an arrow X by the rotation of the moving motors  201 . The plate  100  is disposed between the pair of moving bearings  202 . 
     Vacuum adsorption grooves  205  are formed on the side of the front surface at the center of the upper surface of the punching base  200 . The vacuum adsorption grooves  205  are connected to a suction source  210  shown in FIG. 1 such as a vacuum pump or an aspirator through piping. The reverse surface of the plate  100  on the vacuum adsorption grooves  205  is drawn by operating the suction source  210 , so that the plate  100  is adsorbed and held in the upper surface of the punching base  200 . 
     A pair of rectangular recesses  206  is provided on the side of the rear surface on the upper surface of the punching base  200  (see FIG.  4 ). Templates  300  are respectively mounted on the recesses  206 . One or a plurality of punching blocks for a recording drum (hereinafter referred to as recording drum punching blocks)  301  for forming in the plate  100  the recording drum positioning holes to be respectively fitted on the positioning pins  15  of the recording drum  1  are attached to the template  300 . Further, one or a plurality of punching blocks for a printing machine (hereinafter referred to as printing machine punching blocks)  302  for forming in the plate  100  the printing machine positioning holes to be respectively fitted on the printing machine positioning pins are attached to the template  300 . 
     One end surface of the template  300  is abutted against one side surface to be a reference surface  206   a  of the recess  206 , and the other end surface thereof is urged toward the reference surface  206 a by urging means such as a spring, so that the template  300  is positioned in the recess  206 . 
     A plurality of types of templates  300  are prepared in conformity with the size of the plate  100  and the specification of the printing machine. Each template  300  shown in FIG. 3 has one recording drum punching block  301  and one printing machine punching block  302  carried thereon. The templates  300  shown in FIG. 3 can be also detached and replaced with templates  300  shown in FIG.  4 . Each template  300  shown in FIG. 4 has one recording drum punching block  301  and two printing machine punching blocks  302  carried thereon. 
     Each of the templates  300  can be also provided with a plurality of punching blocks  301  corresponding to a plurality of types of plates  100 , to select the punching block  301  to be used for forming the recording drum positioning holes by entry from the operation panel  700  shown in FIG. 1 in conformity with the size of the plate  100  to be used. Alternatively, it can be also provided with a plurality of punching blocks  302  corresponding to a plurality of types of printing machines, to select the punching block  302  to be used for forming the printing machine positioning holes by entry from the operation panel  700  shown in FIG. 1 in conformity with the specification of the printing machine to be used for printing. 
     A plate front end detecting sensor  207  for detecting the front end of the plate  100  is provided at the center of the upper surface of the punching base  200 . When the plate  100  is arranged between the moving bearings  202 , and the front end of the plate  100  is inserted into the punching blocks  301  and  302  which are attached to the templates  300 , the plate front end detecting sensor  207  is turned on. 
     When the pair of moving bearings  202  is moved toward the center of the punching base  200  by rotating the moving motors  201  from a predetermined position of an origin, outer peripheral surfaces of the holders  203  in the moving bearings  202  are respectively abutted against both the side surfaces of the plate  100 . Accordingly, the plate  100  is positioned at the center of the punching base  200 . Thereafter, the reverse surface of the plate  100  is drawn through the vacuum adsorption grooves  205  by the suction source  210 . Consequently, the plate  100  is fixed to a predetermined position of the punching base  200 . 
     In this state, the recording drum positioning holes are formed at the front end of the plate  100  by the recording drum punching blocks  301  and at the same time, the printing machine positioning holes are respectively formed in predetermined positions of the plate  100  by the printing machine punching blocks  302 . 
     The templates  300  conforming to the size of the plate  100  and the specification of the printing machine may be mounted on the recess  206  of the punching base  200 . Alternatively, the templates  300  having the plurality of punching blocks  301  and  302  corresponding to the plurality of types of plates  100  and the plurality of types of printing machines carried thereon may be mounted, to select the punching blocks  301  and  302  to be used on the basis of the information entered from the operation panel  700 . 
     FIG. 5A is a plan view of the plate  100  having recording drum positioning holes and printing machine positioning holes formed therein, and FIG. 5B is a plan view showing a state where the plate  100  is positioned on the outer peripheral surface of the recording drum  1 . 
     In FIG. 5A, two recording drum positioning holes  101  in a U shape are formed at the front end of the plate  100 , and two printing machine positioning holes  102  are formed in the vicinity of the front end of the plate  100 . 
     In FIG. 5B, the recording drum positioning holes at the front end of the plate  100  are respectively positioned on the positioning pins  15  on the outer peripheral surface of the recording drum  1 , and the front end of the plate  100  is fixed to the outer peripheral surface of the recording drum  1  by the front end clamps  2 . 
     FIG. 6 is a side view showing the construction of the conveying unit  9 . 
     The conveying unit  9  has the first plate carry-in conveying path  91 , the second plate carry-out conveying path  92 , a conveying path switching mechanism  93 , a first conveying mechanism  94 , and a second conveying mechanism  95  provided in a unit main body  900 . 
     The conveying path switching mechanism  93  is constituted by a conveying path switching motor  930 , a gear  931 , a cam gear  932 , a cam follower  933 , and a cam follower guide  934 . The gear  931  is attached to the conveying path switching motor  930 , the cam gear  932  is meshed with the gear  931 , and the cam follower  933  is fixed to the cam gear  932 . The cam follower  933  is engaged with the cam follower guide  934 . The cam follower guide  934  is fixed to the unit main body  900 . The unit main body  900  is supported so as to be swingable by a predetermined supporting member (not shown), centered around its rear part. 
     When the conveying path switching motor  930  is rotated, the cam gear  932  is rotated through the gear  931 , and the cam follower guide  934  is moved up and down by the cam follower  933  fixed to the cam gear  932 . Consequently, the conveying unit  9  swings in a direction indicated by an arrow R. 
     The first conveying mechanism  94  is constituted by a conveying roller driving motor  940 , pulleys  941   a ,  941   b ,  941   c , and  941   d , a belt  942 , and three conveying rollers  943 ,  944 , and  945 . The pulley  941   a  is attached to the conveying roller driving motor  940 , and the pulleys  941   b ,  941   c , and  941   d  are respectively attached to the conveying rollers  943 ,  944 , and  945 . Torque developed by the conveying roller driving motor  940  is transmitted to the pulleys  941   b ,  941   c , and  941   d  through the belt  942  from the pulley  941   a . Consequently, the conveying rollers  943 ,  944 , and  945  are rotated. 
     The second conveying mechanism  95  is constituted by a conveying roller driving motor  950  and conveying rollers  951  and  952 . The conveying rollers  951  and  952  are rotated by the conveying roller driving motor  950 . 
     A nip roller  963  is disposed in close proximity to the conveying roller  943  in the first conveying path  91 . The nip roller  963  is supported so as to be swingable by a swinging member  962 . A gear  961   a  is attached to a nip roller driving motor  960 . The gear  961   a  is meshed with a gear  961   b  attached to the swinging member  962 . When the nip roller driving motor  960  is rotated, the swinging member  962  swings through the gears  961   a  and  961   b , and the nip roller  963  is brought into contact with the conveying roller  943 . Consequently, the plate  100  is held by the conveying roller  943  and the nip roller  963 . 
     A plate front end detecting sensor  970  for detecting the front end of the plate  100  is disposed at a front end of the first conveying path  91 , and a plate rear end detecting sensor  971  for detecting a rear end of the plate  100  is disposed at the center of the first conveying path  91 . 
     The operations of the conveying unit  9  and the punching device  10  will be described while referring to FIGS. 6 to  8 . 
     As shown in FIG. 6, the conveying unit  9  is first moved toward an upper position by the conveying path switching motor  930 . The plate  100  is set on the first conveying path  91  in the conveying unit  9 , and the plate information such as the size of the plate  100  is entered from the operation panel  700  shown in FIG. 1, to issue a work instruction. 
     When the template  300  shown in FIG. 3 has the plurality of punching blocks  301  and  302  carried thereon, information relating to the recording drum positioning holes and the printing machine positioning holes can be also entered as the plate information from the operation panel  700 . 
     The conveying roller driving motor  940  in the first conveying mechanism  94  is rotated, to convey the plate  100  to the punching device  10  as well as to move the moving bearings  202  to the vicinities of both ends of the punching base  200  by the moving motors  201  shown in FIG. 3 on the basis of the information relating to the size of the plate  100 . When the plate front end detecting sensor  207  in the punching device  10  is turned on, the moving bearings  202  are moved toward the center of the punching base  200  by the moving motors  201  depending on the size of the plate  100  with the conveying roller driving motor  940  remaining rotated. Consequently, the plate  100  is positioned at the center of the punching base  200 . 
     The reverse surface of the plate  100  is adsorbed under vacuum through the vacuum adsorption grooves  205 , to fix the plate  100  to the punching base  200 . Thereafter, the conveying roller driving motor  940  and the moving motors  201  are stopped. 
     In this case, the recording drum positioning holes  101  are formed at the front end of the plate  100  by the recording drum punching blocks  301  in the punching device  10  and at the same time, the printing machine positioning holes  102  are respectively formed in predetermined positions of the plate  100  by the printing machine punching blocks  302 . 
     When the templates  300  have the plurality of punching blocks  301  and  302  carried thereon, the plate  100  is simultaneously punched using the punching blocks  301  and  302  selected from the plurality of punching blocks  301  and  302  on the basis of the plate information. 
     The nip roller  963  is then lowered by the nip roller driving motor  960  and is brought into contact with the conveying roller  943 , to hold the plate  100 . The adsorption under vacuum by the vacuum adsorption grooves  205  in the punching base  200  is released. The conveying roller driving motor  940  is then rotated in the reverse direction, to return the plate  100  to the first conveying path  91  in the conveying unit  9  until the plate front end detecting sensor  970  is turned off. 
     As shown in FIG. 7, the conveying unit  9  is swung toward a lower position by the conveying path switching motor  930 . The nip roller  963  is spaced apart from the conveying roller  943  by the nip roller driving motor  960 . 
     The clamp arms  6  are swung, to bring the first driving devices  7  near the outer peripheral surface of the recording drum  1 . The release pin  78  in each of the first driving devices  7  presses a rear end of the front end clamp  2 . Consequently, a clearance is formed between front ends of the front end clamps  2  and the outer peripheral surface of the recording drum  1 . 
     In this state, the conveying roller driving motor  940  is rotated, to convey the plate  100  toward the recording drum  1 , the front end of the plate  100  is inserted into the clearance between the front end of the front end clamps  2  and the outer peripheral surface of the recording drum  1 , and the recording drum positioning holes  101  of the plate  100  are respectively fitted on the positioning pins  15  on the recording drum  1 . 
     After the conveying roller driving motor  940  is stopped, the clamp arm  6  is returned in the reverse direction, to space the release pin  78  in each of the first driving devices  7  apart from the front end clamp  2 . Consequently, the front end of the plate  100  is fixed to the outer peripheral surface of the recording drum  1  by the front end clamps  2 . 
     Thereafter, the conveying roller driving motor  940  is rotated, and the recording drum  1  is rotated, to wind the plate  100  around the outer peripheral surface of the recording drum  1 , and the rear end of the plate  100  is then fixed to the outer peripheral surface of the recording drum  1  by the rear end clamps  3 , as shown in FIG.  3 . 
     The plate  100  is thus fixed to the outer peripheral surface of the recording drum  1 , so that an image is drawn on the plate  100  by the recording head  8  shown in FIG.  1 . 
     When the drawing of the image on the plate  100  by the recording head  8  is terminated, the rear end clamps  3  are released by the first driving devices  7  in the clamp driving device  5 , and the recording drum  1  is then rotated in the reverse direction. 
     As shown in FIG. 8, the front end of the plate  100  is inserted between the conveying rollers  951  and  952  in the second conveying mechanism  95  in the conveying unit  9 , and the conveying rollers  951  and  952  are rotated by the conveying roller driving motor  950 , to pull the plate  100  into the second conveying path  92  in the conveying unit  9 . Thereafter, the front end clamps  2  on the recording drum  1  are released by a second driving device  62  in the clamp driving device  5 , to carry the plate  100  outward through the second conveying path  92  in the conveying unit  9 . 
     In the drawing apparatus according to the present embodiment, the recording drum positioning holes  101  and the printing machine positioning holes  102  are simultaneously formed in the plate  100  by the punching device  10  before the image is drawn by the recording head  8 . Accordingly, the image is drawn by the recording head  8  in a state where the recording drum positioning holes  101  are respectively positioned on the positioning pins  15  of the recording drum  1 . Consequently, the relationship between the image formed on the plate  100  and the printing machine positioning holes  102  can be kept constant irrespective of the variation in the size of the plate  100 . In doing the printing by the printing machine using the plate  100 , the position of printing is not shifted. As a result, no work for correcting the shift in the position of printing is required, thereby improving the efficiency of the printing work. 
     The templates  300  mounted on the punching base  200  in the punching device  10  are replaced, thereby making it possible to respectively form the recording drum positioning holes  101  and the printing machine positioning holes  102  in suitable positions of the plate  100  in conformity with the size of the plate  100  and the specification of the printing machine. 
     Alternatively, the templates  300  having the plurality of punching blocks  301  and  302  corresponding to the plurality of types of plates  100  or the plurality of types of printing machines carried thereon are used, to select the punching blocks  301  and  302  depending on the type of plate  100  and the type of printing machine. Accordingly, it is possible to respectively form the recording drum positioning holes  101  and the printing machine positioning holes  102  in suitable positions of the plate  100  in conformity with the size of the plate  100  and the specification of the printing machine. 
     Consequently, work costs in fabricating the plates  100  corresponding to various types of printing machines are reduced. 
     When the positioning pins  15  are respectively provided in positions, corresponding to the positioning pins of the printing machine, in the recording drum  1 , the recording drum positioning holes  101  and the printing machine positioning holes  102  can be made common. In this case, the templates  300  having the printing machine punching blocks  302  carried thereon are mounted on the punching base  200  in the punching device  10 . 
     Although in the above-mentioned embodiment, the recording drum positioning hole  101  is formed in a U shape, the shape of the recording drum positioning hole  101  is not limited to the U shape. For example, the recording drum positioning hole  101  may have another shape, provided that it is fitted on the positioning pin  15  of the recording drum  1 . 
     Although the present invention has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the present invention being limited only by the terms of the appended claims.