Patent Publication Number: US-2005140999-A1

Title: Image recording system, image recorder and printing data processor

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to an image recording system forming a printed image on the basis of color separation data, and more particularly, it relates to an image recording system mainly forming a printed image for proofreading.  
      2. Description of the Background Art  
      In the field of printing, proofing is performed before printing through a printer for mass printing. In proofing, it is desired to output a printed image as close as possible to a finished image in regular press neither at a high cost nor over a long time.  
      In the field of commercial/industrial design, on the other hand, colors are important design elements for attaining discrimination from others and improving identifiability. Therefore, strict color specification is generally performed for designing the logotype of an enterprise name or a commercial product package or preparing a catalogue or an advertisement therefor. In order to express or reproduce specified colors when printing the logotype, the package, the catalogue or the advertisement, special color inks prepared in response to the specified colors are employed in preference to inks of four colors, i.e., cyan (C), magenta (M), yellow (Y) and black (K) referred to as process colors, for obtaining printed matter exhibiting superior color reproducibility.  
      In order to perform proofreading as to such printed matter, a mode of obtaining a proof image by expressing the special colors as such is desirable for approximating the finish to regular press. A proofing apparatus capable of expressing the special colors is already known (refer to Japanese Patent Application Laying-Open Gazettes Nos. 11-254773 (1999) and 11-70680 (1999), for example).  
      Japanese Patent Application Laying-Open Gazette No. 11-254773 discloses an image transferring recorder forming a desired image by transferring color inks from a transfer film (donor sheet) to a receiver sheet by laser exposure. This image transferring recorder is the so-called direct digital color proofer capable of reproducing a halftone image having resolution similar to that formed on actual printed matter every color with a donor sheet of a plurality of colors, more specifically up to six colors at the maximum, for obtaining a proof image finished approximately to regular press.  
      This image transferring recorder can express the halftone image as such not only with respect to the four process colors but also two additional special colors on the basis of color separation image data of the special colors employed in regular press, so far as a donor sheet capable of expressing the colors can be prepared. If color separation image data for regular press is the one color-separated into a number of colors larger than the upper number of colors (six colors in the above case) simultaneously processible in the image transferring recorder, however, the image transferring recorder cannot reproduce the same as such. In order to obtain a proof image in this case, the image transferring recorder must perform the so-called pseudocolorization of replacing color components of the number of colors exceeding the aforementioned upper limit with color components (those of six colors in the above case) employed in the image transferring recorder. In other words, pseudocolorization is processing of reseparating the color separation data of the color components exceeding the upper limit into color separation data of the color components employed in the image transferring recorder.  
      If the image transferring recorder performs this pseudocolorization, however, no halftone image of the color components subjected to pseudocolorization is formed but a halftone image of each color component forming the proof image disadvantageously differs from a halftone image originally implemented in regular press due to superposition of information of the color components subjected to pseudocolorization.  
      Japanese Patent Application Laying-Open Gazette No. 11-70680 discloses a sublimation-type thermal transfer printer capable of performing simulation printing according to color modes responsive to a product image, i.e., proofing. This thermal transfer printer can selectively execute a plurality of printing modes for printing with special colors when a special color printing mode is selected.  
      When selecting the special color printing mode, the thermal transfer printer first performs printing related to the four process colors, and thereafter performs printing with special colors. However, this thermal transfer printer is not constructed to previously carry ink cartridges of the special colors, and hence an operator must inevitably exchange ink cartridges in a stage of performing printing with the special colors upon completion of printing with the process colors for executing printing in the special color printing mode. In case of printing with a plurality of special colors, further, the operator must determine the special color to be printed and exchange the used ink cartridge every time the thermal transfer printer performs printing as to each special color. This exchange is complicated, and the operator may make a false determination.  
     SUMMARY OF THE INVENTION  
      The present invention relates to an image recording system forming a printed image on the basis of color separation data, i.e., an image recording system mainly forming a printed image for proofreading, and more particularly, it relates to execution of multicolor printing in an image recording system.  
      According to the present invention, the image recording system comprises a) a printing data processor comprising a-1) a color separation data generation element generating a plurality of color separation data by separating printing layout data into a plurality of color components, a-2) a screening element performing screening processing of generating a plurality of halftone image data outputtable in a prescribed output unit in correspondence to the plurality of color components on the basis of the plurality of color separation data, a-3) a first control element controlling operations of the printing data processor and a-4) a color component information generation element generating color component information indicating the color components on which the color separation data is generated; and b) an image recorder comprising b-1) a transfer film storage element storing a plurality of transfer films corresponding to the plurality of color components, b-2) an image recording element performing multicolor image recording processing of successively transferring inks from each of objective transfer films to a receiver sheet by applying an optical beam to superposed objective transfer film on the receiver sheet thereby superpositively visualizing the plurality of halftone image data on the receiver sheet with different color components, wherein the each of objective transfer films is corresponding to each of the plurality of halftone image data among the plurality of transfer films, b-3) a second control element controlling operations of the image recorder, b-4) a first reference information registration element registering first reference information indicating the types of transfer films usable in the image recorder and b-5) a second reference information registration element registering second reference information indicating the types of the plurality of transfer films stored in the transfer film storage element, while either the first control element or the second control element performs comparison processing of comparing description contents of the color component information with at least single registration contents of the first reference information and the second reference information for setting processing necessary for the multicolor image recording processing on the basis of a result of the comparison processing.  
      Thus, an operator may not grasp the contents of image recording performed in the image recorder in advance of the image recording also when he/she must perform operations varying with the contents of the printing layout data or the preparatory situation in the image recorder, whereby no skill is required for the operations.  
      Preferably, the image recorder of the inventive image recording system further comprises b-6) a display element making display for requesting a prescribed operation to an operator, while the image recorder is controlled to be capable of exchanging the transfer films stored in the transfer film storage element with other transfer films not stored in the transfer film storage element in an intermediate stage of the multicolor image recording processing, and the display element displays a prescribed exchange instruction if the plurality of transfer films in the transfer film storage element are inconsistent with a set of transfer films necessary for the multicolor image recording processing as a result of the comparison processing.  
      Thus, it is implemented that the image recorder performs image recording as to color components exceeding the number of the transfer films simultaneously storable in the transfer film storage element, whereby the number of color components for color separation is unlimited. Further, neither the size of the transfer film storage element nor the size of the overall image recorder is increased.  
      Alternatively, the printing data processor of the inventive image recording system preferably further comprises a-5) a pseudocolorization element performing pseudocolorization processing of replacing the color separation data as to an arbitrary color component included in the plurality of color separation data with color separation data as to another color component, wherein the another color component is at least one color component corresponding to any transfer film already registered in the first reference information among the plurality of transfer films, the pseudocolorization processing is performed on color separation data as to a color component determined as a transfer film of a type unregistered in the first reference information as the result of the comparison processing in the first control element, and the screening element performs the screening processing on color separation data present after the pseudocolorization.  
      Thus, the operator may not determine necessariness/unnecessariness of pseudocolorization, whereby he/she can perform the operations also when he/she has no knowledge as to color separation.  
      Accordingly, an object of the present invention is to provide an image recording system setting processing contents related to image recording processing on the basis of the types of color components employed for printing data.  
      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 block diagram schematically showing the structure of an image recording system according to each of first and second embodiments of the present invention;  
       FIG. 2  is a longitudinal sectional view schematically showing the mechanical structure of an image transferring recorder;  
       FIG. 3  illustrates an exposure condition set table;  
       FIGS. 4A  to  4 C illustrate a rotary rack management table;  
       FIG. 5  illustrates a color table;  
       FIG. 6  is a sectional view showing the details of a receiver sheet supply part and a donor sheet supply part;  
       FIG. 7  is a perspective view partially showing a donor sheet delivery mechanism;  
       FIG. 8  is a perspective view showing a drum;  
       FIG. 9  is an enlarged view showing a receiver sheet and a donor sheet wound on the drum;  
       FIG. 10  illustrates the forward ends of the receiver sheet and the donor sheet completely wound on the drum and a peeler moved down to a peeling position;  
       FIG. 11  illustrates the forward end of the donor sheet in a state being peeled;  
       FIG. 12  is a flow chart of image recording processing according to the first embodiment;  
       FIG. 13  illustrates a flow of data related to image recording;  
       FIG. 14  is a flow chart of processing in image transferring recording; and  
       FIG. 15  is a flow chart of image recording processing according to the second embodiment. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     First Embodiment  
      &lt;Image Recording System&gt; 
       FIG. 1  is a block diagram schematically showing the structure of an image recording system  1000  according to a first embodiment of the present invention. The image recording system  1000  mainly comprises an image transferring recorder  1 , a raster image processor  800  and a laminator  900 . Communication lines CL connect the image transferring recorder  1  with the raster image processor  800  and the laminator  900  respectively.  
      The raster image processor  800  reads layout data describing layout information on characters and images to be expressed in printed matter from a layout processor  1500  creating the layout data directly or temporarily through a recording medium. The layout data is preferably described in a prescribed page description language (PDL) such as PostScript (registered trademark by Adobe Systems). The raster image processor  800  is a printing data processor, which is color-separating the read layout data for creating raster data (color separation data) as to a plurality of color components and further performing screening processing (halftone image processing) on the raster data as to the respective color components for generating halftone image data as to the respective color components. The one generated halftone image data is for regular output, supplied to a prescribed output unit  2000  such as an image setter, a CTP or a digital printer for prepress processing or regular press (formation of final printed matter), and the other is for proofing using the image transferring recorder  1 .  
      The image transferring recorder  1  transfers color inks of color transfer films (donor sheets) to a receiver sheet by laser exposure thereby forming a desired image on the receiver sheet. This image transferring recorder  1  is the so-called direct digital color proofer capable of reproducing a halftone image having resolution similar to that formed on actual printed matter every color, with donor sheets of a plurality of colors corresponding to halftone image data output from the raster image processor  800 , thereby obtaining a proof image finished approximately to regular press.  
      The laminator  900  heats/pressurizes the receiver sheet to which the image is transferred in the image transferring recorder  1  and an arbitrary printing paper (regular paper) to be printed thereby transferring the image formed on the receiver sheet to the printing paper.  
      In other words, the image recording system  1000  according to the first embodiment is a system capable of obtaining a proof image finished equivalently to final printed matter in the image transferring recorder  1 .  
      &lt;Raster Image Processor&gt; 
      The raster image processor  800  is now described. The so-called general-purpose personal computer reads and runs a prescribed program for implementing the raster image processor  800  through the function of a CPU, a ROM or a RAM of the personal computer. The raster image processor  800  mainly comprises a control part CTL 1 , a data interpretation part  810 , a correction processing part  820 , a screening processing part  830  and a storage part  840 .  
      The control part CTL 1  controls operations of the respective parts of the raster image processor  800 , data transfer between the raster image processor  800  and external devices and the like. As described below, the control part CTL 1  also performs to determine whether or not the image transferring recorder  1  is capable of image recording as to color components obtained by color separation as well as to determine necessariness/unnecessariness of pseudocolorization as to a certain color component, by referring to the description of a color table TBL 3 .  
      The data interpretation part  810  interprets the description contents of the layout data described in a prescribed format, preferably in a prescribed PDL for generating raster data (color separation data) every color component employed in regular press while generating information (color component information) for specifying each color component. The color component information is referred at the time of deciding processing to be performed on the image transferring recorder  1 , as described later. More specifically, specific color codes are previously set for all color components employed in regular press, and the layout data has descriptions about color information with color codes for specifying the color of every object such as a character, a linework or an image in the layout data. The colors of the objects were assigned when the objects were laid out. The data interpretation part  810  generates the raster data (color separation data) by separating the layout data into a plurality of color components on the basis of the color information described in the layout data. At the same time, the data interpretation part  810  generates color component information specifying the color components subjected to generation of the color separation data. In other words, the color component information also indicates as to which color components color separation has been performed.  
      The correction processing part  820  performs correction such as the so-called color matching and other correction processing on the color separation data. The former is necessary for reproducing the colors expressed in the layout data with fidelity respectively at the regular output on the output unit  2000  and the formation of the proof image on the image transferring recorder  1 . In other words, the correction processing part  820  obtains color separation data for the respective apparatuses. As to the color separation data to be supplied to the image transferring recorder  1 , the correction processing part  820  also performs pseudocolorization processing for replacing some color components with other color components in advance of color matching, if necessary.  
      The screening processing part  830  performs screening processing (halftone image processing) generating halftone image data on the basis of properly corrected color separation data. In other words, screening processing is processing of generating halftone image data expressing binary images having high resolution of about 2400 dpi to 4000 dpi from color separation data having multilevel gradation. The screening processing part  830  individually performs this screening processing on the color separation data for the output unit  2000  and the color separation data for the image transferring recorder  1  respectively. The screening processing part  830  supplies halftone image data obtained from the former processing to the output unit  2000  for regular output. Further, the screening processing part  830  supplies halftone image data obtained from the latter processing to the image transferring recorder  1  for formation of the proof image.  
      The storage part  840  stores the read layout data, the generated color separation data, and halftone image data etc. as well as the color table TBL 3  describing information as to color components allowing image formation in the image transferring recorder  1 , more specifically, information as to color types of donor sheet rolls (described later) prepared for image recording in the image transferring recorder  1 . The color table TBL 3  is described later.  
      &lt;Overall Structure of Image Transferring Recorder&gt; 
      The image transferring recorder  1  is now described. As shown in  FIG. 1 , the image transferring recorder  1  mainly comprises a receiver sheet supply part  100 , a donor sheet supply part  200 , an image recording part  300 , a discharge part  400 , a storage part  500  and a display operation part  600 .  FIG. 2  is a longitudinal sectional view schematically showing the mechanical structure of the image transferring recorder  1 . A cover  10  covers the surface of the image transferring recorder  1 . Leg parts  20  support the image transferring recorder  1 .  
      The control part CTL 2  controls operations of the respective parts of the image transferring recorder  1 , data transfer between the image transferring recorder  1  and external devices etc. More specifically, the control part CTL 2  selects a donor sheet roll to be used, determines necessariness/unnecessariness of exchange of any donor sheet roll following this selection and controls the image transferring recorder  1  according to the contents of this determination.  
      The receiver sheet supply part  100  supplies a receiver sheet to the image recording part  300 . The donor sheet supply part  200 , capable of supplying a plurality of types of donor sheets, can selectively supply a donor sheet to the image recording part  300  from among the plurality of types of donor sheets. On the image recording part  300 , the receiver sheet is wound on a drum  310  and the donor sheet is further wound on it. A laser beam is emitted from a recording head  350  toward the donor sheet superposed on the receiver sheet on the basis of halftone image data received from the raster image processor  800 , thereby exposing the receiver sheet. Formation of an image on the receiver sheet is implemented by adhesion and transfer onto it of sublimated and/or melted donors from a portion of the donor sheet heated through the laser exposure. Formation of a multicolor image is implemented by adhering the donors of the donor sheet to the precisely same receiver sheet every color component on the basis of halftone image data as to a plurality of different colors (yellow, magenta, cyan and black, for example). This is attained by successively exchanging donor sheets of the respective colors and laser-exposing the same, while keeping the receiver sheet wound on the drum  310 .  
      The image-formed receiver sheet is discharged through the discharge part  400  and taken from the image transferring recorder  1 . The separately provided laminator  900  heats/pressurizes the receiver sheet on an arbitrary printing paper to be printed. Thus, the donors are transferred to the printing paper, thereby forming an image.  
      The storage part  500  stores the halftone image data received from the raster image processor  800  as well as an exposure condition setting table TBL 1  describing exposure conditions for donor sheet rolls (described later) for a plurality of color components prepared for image recording and a rotary rack management table TBL 2  indicating a storage situation of the donor sheet rolls in a rotary rack  210  (described later) storing the donor sheet rolls subjected to exposure.  
       FIG. 3  illustrates the exposure condition setting the table TBL 1 . The exposure condition setting table TBL 1  shown in  FIG. 3  associates flags C 11  showing identification numbers for identifying the color components, color codes C 12  indicating the respective color components, roll names C 13  of the donor sheet rolls corresponding to the respective color components, light quantities C 14  of the laser beam emitted from the recording head  350  for performing exposure with the donor sheet rolls and rotational frequencies C 15  of the drum  310  for registering exposure conditions for the respective color components in the image transferring recorder  1 . Those identical to the colors specified in the layout data are employed for the color codes C 12 . In the exposure condition setting table TBL 1  shown in  FIG. 3 , the process colors are registered among 1 to 4 of flags C 11  and the special colors among 5 to 20, respectively. In this case, it follows that the image transferring recorder  1  according to the first embodiment is capable of image recording as to 20 color components at the maximum. The number of the color components is not restricted to this. In case donor sheet rolls for a larger number of special colors are prepared, the image transferring recorder  1  can use a larger number of color components for image recording as long as the color components are registered in the exposure condition setting table TBL  1 .  
       FIGS. 4A  to  4 C illustrate the rotary rack management table TBL 2  (TBL 2   a  to TBL 2   c ). The rotary rack management table TBL 2  shown in  FIGS. 4A  to  4 C associates section numbers C 21  showing identification numbers for identifying the storage positions of the donor sheet rolls in the rotary rack  210  with color codes C 22  showing the color components of the donor sheet rolls stored in the storage positions respectively.  
      According to the first embodiment, the storage part  840  of the raster image processor  800  stores contents identical to parts of the contents of the exposure condition setting table TBL 1  as the color table TBL 3 .  FIG. 5  illustrates the color table TBL 3 . The color table TBL 3  shown in  FIG. 5  describes the flags C 11 , the color codes C 12  and the roll names C 13  among the description contents of the exposure condition setting table TBL 1 .  
      As to data entry in the color table TBL 3 , an operator may input the same contents as those described in the exposure condition setting table TBL 1  punctatim, or the control part CTL 1  of the raster image processor  800  may extract the contents of the exposure condition setting table TBL 1 .  
      Preferably, it is assumed in the first embodiment that donor sheet rolls of color types larger in number than the donor sheet rolls simultaneously storable in the rotary rack  210  and the exposure condition setting table TBL 1  registers this information. According to the first embodiment, as described later, a proof image finished approximately to a regularly output image from a regular printing press can be obtained by properly exchanging the stored donor sheet rolls even if color components larger in number than those simultaneously storable in the rotary rack  210  are employed.  
      The display operation part  600  is the so-called touch panel displaying the operating situation of the image transferring recorder  1  and enabling the operator to perform a prescribed input operation. The display operation part  600 , not shown in  FIG. 2 , is preferably arranged on the upper or front surface of the body of the image transferring recorder  1 . Alternatively, the display operation part  600  may be properly supported by support bodies to be provided on a side portion of the body of the image transferring recorder  1 , for example, independently of the body of the image transferring recorder  1 . Further alternatively, the display operation part  600  may be replaced with a separately provided personal computer enabling the operator to grasp the operating situation or perform the input operation.  
      The mechanical components of the image transferring recorder  1  and operations thereof are now successively described.  
      &lt;Receiver Sheet Supply Part&gt; 
       FIG. 6  is a sectional view showing the details of the receiver sheet supply part  100  and the donor sheet supply part  200 .  FIG. 7  is a perspective view partially showing a donor sheet delivery mechanism  250 . The receiver sheet supply part  100  is now described.  
      The receiver sheet supply part  100  has a receiver sheet roll  130 . A receiver sheet  140  is wound on a core  132  of the receiver sheet roll  130 . The receiver sheet  140  has a support layer  142  and a receiver layer  144  stacked on the support layer  142  (see  FIG. 9 ). In the receiver sheet roll  130 , the receiver layer  144  is wound on the outer side of the support layer  142  (this receiver sheet roll  130  is hereinafter also referred to as “revolute receiver sheet roll  130 ”). The receiver sheet roll  130  is set to be rotatable about the central axis of the core  132 .  
      The receiver sheet supply part  100  further has transport rollers  154  and  155 , a support guide  156 , a receive sheet cutting part  160  and a detection sensor  170  detecting an end point of the receiver sheet  140 .  
      The transport roller  154  has a pair of rollers  154   a  and  154   b , while the transport roller  155  also has a pair of rollers  155   a  and  155   b . Driving means (not shown) drive the rollers  154   a  and  155   a . The rollers  154   b  and  155   b  can hold the receiver sheet  140  between the same and the rollers  154   a  and  155   a  with prescribed pressure respectively.  
      The rollers  154   b  and  155   b  transport the receiver sheet  140  by rotating oppositely to the rollers  154   a  and  155   b  in a follower manner. This driving mechanism can deliver or return the receiver sheet  140  toward or from the image recording part  300 .  
      The receiver sheet supply part  100  having the aforementioned structure supplies the receiver sheet  140  to the image recording part  300 .  
      First, the transport roller  154  holds the forward end of the receiver sheet roll  130  so that the aforementioned driving mechanism including a motor (not shown) draws out the receiver sheet  140  along arrow AR 11 . Thus, the receiver sheet roll  130  rotates along arrow AR 11  to deliver the receiver sheet  140 . The transport rollers  155  hold the receiver sheet  140  so that the support guide  156  guides and transports the same.  
      The receiver sheet cutting part  160  cuts the receiver sheet  140  transported in the aforementioned manner into a prescribed length. The detection sensor  170  is employed for the measurement of the length of the donor sheet  240 . The measurement of the length is implemented by detecting the forward end of the receiver sheet  140  with the detection sensor  170  and considering the rotational frequency of the motor or the like. The receiver sheet cutting part  160  cuts the receiver sheet  140  into the prescribed length on the basis of the result of this measurement and supplies the same to the image recording part  300 .  
      &lt;Donor Sheet Supply Part&gt; 
      Referring again to  FIG. 6 , the donor sheet supply part  200  is described. The donor sheet supply part  200  has the rotary rack  210 . Driving means (not shown) rotates/drives the rotary rack  210  along arrow AR 1  about a rotation axis  213 . The rotary rack  210  stores a plurality of donor sheet rolls  230 , which are “radially” arranged about the rotation axis  213 . In other words, the rotary rack  210  functions as donor sheet storage means according to the present invention. A base  201  supporting the rotary rack  210  and the driving means therefor is present under the rotary rack  210  (see  FIG. 2 ).  
      Each donor sheet roll  230  has a hollow core  232 , a donor sheet  240  wound thereon and flanges  234  inserted into both sides of the core  232 . As shown in  FIG. 7 , three bars  258  provided on the rotary rack  210  hold these flanges  234  thereby rotatably holding the donor sheet roll  230 . A part of each bar  258  is provided with a sticking out stopper  259  for regulating axial movement of the donor sheet roll  230 .  
      Each donor sheet  240  has a support layer  242  and a color ink layer  244  (see  FIG. 9 ), which are stacked with each other. In the donor sheet roll  230 , the color ink layer  244  is wound on the outer side of the support layer  242  (this donor sheet roll  230  is hereinafter also referred to as “revolute donor sheet roll  230 ”). As described later, the color ink layer  244  has donor inks, which are transferred to the receiver sheet  140  by laser exposure.  
      Referring to  FIG. 6 , six donor sheet rolls  230  each having the aforementioned structure are stored one by one in six sections formed in the rotary rack  210 . The selection from the six types of donor sheets  240  is performed on the basis of the contents of printing data to be processed, as described later. For example, the rotary rack  210  may store donor sheets  240  of the four process colors of cyan (C), magenta (M), yellow (Y) and black (K) and donor sheets  240  of two special colors such as gold and silver, or may store donor sheets  240  of further specific colors selected in place of the aforementioned donor sheets  240  of the process colors.  
      The rotary rack  210  further has a plurality of donor sheet delivery mechanisms  250 . The donor sheet delivery mechanisms  250  are provided in correspondence to the plurality of donor sheet rolls  230  respectively. Referring to  FIG. 6 , the rotary rack  210  is provided with six donor sheet delivery mechanisms  250 . Each donor sheet delivery mechanism  250  is now described with reference to  FIGS. 6 and 7 .  
      Each donor sheet delivery mechanism  250  has a feed roller  254 , a support guide  256  and the three bars  258 . As hereinabove described, the three bars  258  come into contact with the outer peripheries of the flanges  234  for holding the donor sheet roll  230 .  
      The feed roller  254  has rollers  254   a  and  254   b . The roller  254   a , driven by driving means (not shown), can hold the donor sheet  240  between the same and the roller  254   b  with prescribed pressure. The roller  254   b  rotates oppositely to the roller  254   a , thereby transferring the donor sheet  240 . The donor sheet  240  held by the rollers  254   a  and  254   b  can be delivered or returned. The donor sheet roll  230  rotates following transfer of the donor sheet  240 . The three bars  258  hold the donor sheet roll  230  while relatively rotating with respect to the flanges  234 .  
      The donor sheet delivery mechanism  250  having the aforementioned structure supplies each donor sheet  240  to the image recording part  300 . The driving means (not shown) drives the feed roller  254  holding the forward end of the donor sheet roll  230 . Thus, the donor sheet roll  230  rotating along arrow AR 21  delivers the donor sheet  240  along arrow AR 2 . A donor sheet transport part  270  cuts the donor sheet  240  into a prescribed length and supplies the same to the image recording part  300 .  
      Each feed roller  254  provided in the rotary rack  210  has a function of temporarily curling the part of the donor sheet  240  just delivered from the donor sheet roll  230  oppositely to a curling direction in the wound state and feeding the same afterward. The feed roller  254  feeds the donor sheet  240  to the donor sheet transport part  270 , with its delivered part from the donor sheet roll  230  temporarily oppositely curled in advance. Accordingly, the donor sheet  240  to be fed is remedied a tendency to curl derived from a wound state on the donor sheet roll  230  to some extent, and is never supplied to the donor sheet transport part  270  or the drum  310  in an excessively curled state.  
      Referring again to  FIG. 6 , the donor sheet supply part  200  further has the donor sheet transport part  270 . The donor sheet transport part  270  has transport rollers  274  and  275 , a guide  276 , a donor sheet cutting part  280  and a detection sensor  290  detecting an end of each donor sheet  240 .  
      The transport roller  274  has a pair of rollers  274   a  and  274   b , while the transport roller  275  also has a pair of rollers  275   a  and  275   b . Driving means (not shown) drives the rollers  274   a  and  275   a . The rollers  274   b  and  275   b  can hold the donor sheet  240  between the same and the rollers  274   a  and  275   a  with prescribed pressure respectively.  
      The rollers  274   b  and  275   b  transport the donor sheet  240  by rotating oppositely to the rollers  274   a  and  275   a . This driving mechanism can deliver or return the donor sheet  240  toward or from the image recording part  300 .  
      The donor sheet cutting part  280  cuts the donor sheet  240  transported in the aforementioned manner into a prescribed length. The detection sensor  290  is employed for the measurement of the length of the donor sheet  240 . The measurement of the length is implemented by detecting the end of the donor sheet  240  with the detection sensor  290  and considering the rotational frequency of a motor constituting the driving mechanism or the like. The donor sheet cutting part  280  cuts the donor sheet  240  into the prescribed length on the basis of the result of this measurement and supplies the same to the image recording part  300 .  
      &lt;Exchange of Receiver Sheet Roll and Donor Sheet Roll&gt; 
      The image transferring recorder  1  according to the first embodiment is constituted to allow to detach any donor sheet roll  230  and replace the same with a new donor sheet roll  230  at the time of performing image recording processing or terminating processing as to one color component, in case that printing data subjected to image recording has a large number of color components. When the receiver sheet  140  and the donor sheet  240  are consumed, the used receiver sheet roll  130  and the used donor sheet roll  230  must be detached and be replaced to another receiver sheet roll  130  and another donor sheet roll  230  on which a new receiver sheet  140  and a new donor sheet  240  are wound respectively. This is now described with reference to  FIG. 2  again.  
      First, the exchange of the donor sheet roll  230  comes to be enabled by opening a lid  12  on the image transferring recorder  1  (see  FIG. 2 ). At this time, the image transferring recorder  1  rotates the rotary rack  210  by a prescribed operation thereby moving the donor sheet roll  230  to be exchanged to a prescribed exchange position P 12  corresponding to the lid  12 .  
      The image transferring recorder  1  may have to exchange a plurality of donor sheet rolls  230  depending on the number of color components employed for image recording. In this case, it is also allowed to continuously exchange the plurality of donor sheet rolls  230  by rotating the rotary rack  210  and successively moving the donor sheet rolls  230  to the prescribed exchange position P 12 . When the plurality of donor sheet rolls  230  are exchanged, therefore, the successive exchange of the plurality of donor sheet rolls  230  is enabled on the precisely same exchange position P 12  after opening the lid  12 .  
      On the other hand, the exchange of the receiver sheet roll  130  is enabled by opening another lid  11  on the image transferring recorder  1 . As the exchange of the receiver sheet roll  130  is performed with excellent workability by ensuring a relatively large space in the vicinity of an opening of the lid  11  and without rotating the rotary rack  210 , the receiver sheet roll  130  is exchanged more easily than the donor sheet roll  230 . Generally, the exchange of the receiver sheet rolls  130  is performed at timing different from that for exchanging the donor sheet rolls  230 . Therefore, the labor remains unchanged despite the lid  11  provided on a position different from that of the lid  12 .  
      &lt;Image Recording Part&gt; 
      The image recording part  300  has the drum  310  (see  FIG. 2 ).  FIG. 8  is a perspective view showing the drum  310 . The drum  310 , having a hollow cylindrical shape, is rotatably held on a frame (not shown). A driving mechanism (not shown) rotates/drives the drum  310  about an axis  312 .  
      A plurality of holes  314  are formed on the surface of the drum  310 . The holes  314  are connected to a blower (not shown) through the hollow portion of the drum  310  etc. When the receiver sheet  140  and the donor sheet  240  are placed on the drum  310  and the blower is operated, the drum  310  absorbs the sheets  140  and  240 .  
      The drum  310  also has a plurality of grooves  322  linearly provided in parallel with the rotation axis of the drum  310 . The drum  310  further has another plurality of grooves  324  linearly provided in parallel with the rotation axis of the drum  310 , similarly to the plurality of grooves  322 . The grooves  324  are located on positions corresponding to those of the grooves  322  respectively in the direction parallel to the rotation axis of the drum  310 . Thus, the drum  310  has two lines of grooves  322  and  324 , which are employed for peeling the donor sheet  240  and the receiver sheet  140  respectively.  
      The receiver sheet  140  supplied by the receiver sheet supply part  100  is first wound on the drum  310 . The receiver sheet  140  is absorbed by and wound on the drum  310  with the rotation of the drum  310 .  
      Then, a donor sheet  240  supplied from the donor sheet supply part  200  is wound on the receiver sheet  140 . The receiver sheet  140  and the donor sheet  240  are different in size from each other. More specifically, the donor sheet  240  is larger than the receiver sheet  140  in both of the vertical and transverse directions. Therefore, the donor sheet  240  is adsorbed by the drum  310  through a part larger than the receiver sheet  140 . The donor sheet  240  is adsorbed by and wound on the drum  310  rotating in the same direction as that for fixing the receiver sheet  140 .  
       FIG. 9  is an enlarged view showing the receiver sheet  140  and the donor sheet  240  wound on the drum  310 . The receiver sheet  140  has the support layer  142  and the receiver layer  144 , while the donor sheet  240  has the support layer  242  and the color ink layer  244 . The receiver sheet  140  is supplied from the revolute receiver sheet roll  130  and is wound on the drum  310 , with the receiver layer  144  located just on the support layer  142 . The donor sheet  240  is supplied from the revolute donor sheet roll  230  and is wound on the receiver sheet  140  and the drum  310 , with the color ink layer  244  located just under the support layer  242 . Thus, the receiver sheet  140  and the donor sheet  240  are so wound on the drum  310  that the color ink layer  244  of the donor sheet  240  is in contact with the receiver layer  144  of the receiver sheet  140 , as shown in  FIG. 9 . Donor inks of the color ink layer  244  having such positional relation are transferred to the receiver sheet  140  through laser exposure with the recording head  350 , as described below.  
      The image recording part  300  further has the recording head  350  (see  FIG. 2 ). The recording head  350  can emit beam-shaped laser light. Donor inks located on positions of the donor sheet  240  irradiated with the laser beam are transferred to the surface of the receiver sheet  140 . The recording head  350  can linearly move in the direction parallel to the rotation axis of the drum  310  through a driving mechanism (not shown). Therefore, combination with rotation of the drum  310  and linear movement of the recording head  350  makes it possible to laser-expose desired positions of the donor sheet  240  covering the receiver sheet  140 . In laser exposure, the drum  310  preferably rotates oppositely to the direction for winding the receiver sheet  140  and the donor sheet  240  thereon.  
      On the image transferring recorder  1 , transfer of a desired image to the receiver sheet  140  is implemented by scanning the donor sheet  240  with the laser beam, i.e., an optical beam for drawing, and laser-exposing only corresponding positions on the basis of image information.  
      &lt;Peeling and Discharge of Sheets&gt; 
      When completing a transfer operation from each donor sheet  240 , the image transferring recorder  1  peels the donor sheet  240 .  FIG. 10  illustrates the forward ends of the receiver sheet  140  and the donor sheet  240  completely wound on the drum  310 , and a peeler  332  moved down to a peeling position P 34 .  FIG. 11  shows the forward end of the donor sheet  240  in a state being peeled. A plurality of peelers  332  are linearly provided above the drum  310  in parallel with the rotation axis of the drum  310 . The peelers  332  are provided in the same number as the plurality of grooves  322  on positions corresponding to the grooves  322  respectively in the direction parallel to the rotation axis of the drum  310 .  
      In order to peel the donor sheet  240 , the drum  310  is rotated at a prescribed peeling speed along arrow AR 31 . Then, the forward end of each peeler  332  is moved from a prescribed standby position not in contact with the drum  310  to the position P 34  coming into contact with the drum  310 , while not coming into contact with the donor sheet  240 . Following rotation of the drum  310  along arrow AR 31 , each peeler  332  peripherally relatively moves on the drum  310  along the surface thereof. The forward end of each peeler  332  relatively moves on the surface of the drum  310  following the shape of the corresponding groove  322 , then it slides into under side of the donor sheet  240 . The donor sheet  240  moves along the upper surface of the peeler  332 . Force exceeding the suction force of the blower acts on the donor sheet  240  thereby peeling the donor sheet  240  from the drum  310 . The peeler  332  rises in a direction further separating from the drum  310  before coming into contact with the receiver sheet  140  and moves to the standby position. With the drum  310  continuously rotating after the forward end of the donor sheet  240  is peeled, the donor sheet  240  is further peeled from the drum  310  and the receiver sheet  140 . At this time, the drum  310  remains adsorbing the receiver sheet  140  due to the suction force of the blower, so that only the donor sheet  240  can be peeled.  
      The donor sheet  240  peeled through the aforementioned operation is discharged into a donor sheet recovery box  40  comprised outside the image transferring recorder  1  further through the discharge part  400 .  
      In order to continuously perform image recording as to another color component, another donor sheet  240  of another color is wound on the receiver sheet  140  still wound on the drum  310 . Similarly to the aforementioned case, donor inks from the donor sheet  240  is transferred to the receiver sheet  140  and thereafter the donor sheet  240  is peeled and discharged.  
      Image recording and subsequent peeling is similarly repeated until image recording as to all color components is terminated. In case of recording an image as to the four color components of cyan (C), magenta (M), yellow (Y) and black (K), for example, the repetition of the aforementioned operations on the donor sheets  240  of these four types causes transfer of a color halftone image of the process colors to the receiver sheet  140 .  
      When image recording as to all color components is terminated, the receiver sheet  140  to which a plurality of types of donor inks have been transferred is peeled. Similarly to the case of peeling the donor sheet  240 , peeling of the receiver sheet  140  is implemented by sliding the peelers  332  into the grooves  324  while rotating the drum  310 . The receiver sheet  140  peeled in the aforementioned manner is discharged to a tray  50  provided thereon through the discharge part  400 .  
      The operator carries the receiver sheet  140  discharged on the tray  50  to the aforementioned separately provided laminator  900 , which in turn transfers the image of the plurality of colors of donor inks formed on the receiver sheet  140  to a regular paper. Thus, a proof image is transferred to the regular paper.  
      &lt;Image Recording Processing&gt; 
      The aforementioned image recording system  1000  can form a desired color image on the receiver sheet  140 .  FIG. 12  is a flow chart of image recording processing in the image recording system  1000 .  FIG. 13  illustrates a flow of data related to image recording.  
      First, it is previously performed to register prescribed contents in each of the tables TBL 1  to TBL 3  (step S 1 ). The exposure condition setting table TBL 1  is intended to register information as to all donor sheet rolls  230  prepared to be used in the image transferring recorder  1 . In case of the exposure condition setting table TBL 1  shown in  FIG. 3 , the flags C 11 , the color codes C 12 , the roll names C 13 , the light quantities C 14  of the laser beam in exposure and the rotational frequencies C 15  of the drum  310  are registered. The rotary rack management table TBL 2  is intended to register respective storage positions of the rotary rack  210  and the stored donor sheet rolls  230  in association with each other. Referring to  FIGS. 4A  to  4 C, the section numbers C 21  for identifying the storage positions of the donor sheet rolls  230  is associated with the color codes C 22 . The color table TBL 3  is intended to register the flags C 11 , the color codes C 12  and the roll names C 13  of the same contents as those described in the exposure condition setting table TBL 1 .  
      The data stored in the exposure condition setting table TBL 1  are prepared for every donor sheet  240  usable on the image transferring recorder  1 . The types of the usable donor sheets  240  not frequently updated, it is not needed to update the registration contents of the exposure condition setting table TBL 1  every image recording.  
      When the tables TBL 1  to TBL 3  are prepared, the raster image processor  800  reads layout data DL for printing from the layout processor  1500  (step S 2 ). Alternatively, the raster image processor  800  may read layout data DL already stored in the storage part  840 . The read layout data DL is inputted in the data interpretation part  810 . The data interpretation part  810  interprets the description contents of the layout data DL, and generates first color separation data DCS 1  which expresses an image obtained by color-separating a printed image expressed by the layout data DL every ink color used in regular press, on the basis of the described color information. When performing color separation for printing the printed image expressed by the layout data DL with inks of seven colors of cyan (C), magenta (M), yellow (Y), black (K), green (G), white (W) and violet (V), for example, the data interpretation part  810  generates seven first color separation data DCS 1  corresponding to the colors respectively.  
      Along with this generation of the first color separation data DCS 1 , the data interpretation part  810  generates color component information CI indicating as to what color components the first color separation data DCS 1  have been generated (step S 4 ). The color component information CI corresponds to information indicating in what order with which color components images should be formed on the image transferring recorder  1 . Information specifying the types of the color components (seven colors in the aforementioned case) and the order for image formation is described as the color component information CI according to a prescribed format with color codes. In this embodiment, it is assumed that the color component information CI is described on the assumption that image-recording of respective color components of color codes (c, m, y, k, s 2 , s 11  and s 16 ) corresponding to the aforementioned seven colors is successively executed from the head-coded color component.  
      The roll names corresponding to the color codes s 2 , s 11  and s 16  are green, white and violet respectively (see  FIG. 5 ). Preferably, the order for image formation with the plurality of color components is decided to be inverse to that for overprinting with inks in regular press. This is because, if the image on the receiver sheet  140  is transferred to the regular paper on the laminator  900  in this case, the proof image is formed on the regular paper, with its ink layers stacked in inverse order to the ink transfer order on the image transferring recorder  1 . Thus, the order of forming the ink layers in the proof image is identical to the order of forming ink layers to be implemented in regular press, whereby identifiability of the proof image with respect to an image to be obtained by regular press can be improved.  
      For example, process color inks are generally superposed on special color inks in regular press. Accordingly, image-recording with the process colors is generally executed in advance of that with the special colors on the image transferring recorder  1 . Among the process colors, black is often subjected to print in first in regular press. Therefore, recording in black on the image transferring recorder  1  is performed at the end. Among special colors, on the other hand, white is subjected to print relatively later in regular press. Therefore, recording in white on the image transferring recorder  1  is performed in a relatively early stage.  
      When the interpretation part  810  generates the color component information CI, the control part CTL 1  compares/collates the color component information CI with the color table TBL 3 . Thus, the control part CTL 1  determines whether or not the color components described in the color component information CI are those registered in the color table TBL 3  (step S 5 ). Now, all of the aforementioned seven color codes (c, m, y, k, s 2 , s 11  and s 16 ) are registered in the color table TBL 3 . This means that the exposure condition setting table TBL 1  includes registrations of these color codes (c, m, y, k, s 2 , s 11  and s 16 ), whereby it follows that it is determined at the step S 5  whether or not the proof image can be formed with such donor sheet  240  as expressing the color components of the inks employed in regular press.  
      For the present, a case where it is determined that all of the color components described in the color component information CI are registered in the color table TBL 3  (YES at the step S 5 ) as a result of comparison/collation is described. In this case, prescribed correction processing is performed (step S 7 ) on the first color separation data DCS 1  of the respective color components through the function of the correction processing part  820  and it causes generation of second color separation data DCS 2  for the respective color components. In the aforementioned case, for example, the second color separation data DCS 2  are obtained as such as to all color components since all of the color components of the seven colors employed in regular press are previously registered on the color table TBL 3 .  
      When the second color separation data DCS 2  is obtained, halftone image data DS, actually employed for transferring the image in the image transferring recorder  1 , is generated through the function of the screening processing part  830  (step S 8 ).  
      Then, the color component information CI is transferred to the image transferring recorder  1  (step S 9 ). The control part CTL 2  of the image transferring recorder  1  compares/collates the received color component information CI with the rotary rack management table TBL 2  and determines whether or not the donor sheet roll  230  must be exchanged (step S 10 ). According to the first embodiment, the control part CTL 1  of the raster image processor  800  generates the information as to the types of the donor sheets  240  to be employed in the image transferring recorder  1  and after that, supplies the same to the image transferring recorder  1 , whereby the operator may neither determine which donor sheet rolls  230  are necessary nor manually input the information as to the employed donor sheets  240  in the image transferring recorder  1 . Thus, the operator requires no deep knowledge as to recording of the proof image but automation of operations is prompted.  
      The rotary rack  210  can store six donor sheet rolls  230  at the maximum, and hence any of the stored donor sheet rolls  230  must be exchanged at least once in order to record the image as to the seven color components indicated in the aforementioned color codes. The image transferring recorder  1  according to the first embodiment is controlled to be capable of exchanging the donor sheet roll  230  in an intermediate stage of image recording processing, when necessary. The procedure of the exchange can be variously set according to the types of the donor sheet rolls  230  stored in the rotary rack  210  or the types of the donor sheet rolls  230  to be employed. In the first embodiment, it is assumed that the control part CTL 2  so controls as to preferentially exchange donor sheet rolls  230  not to be used for image recording but stored in the rotary rack  210  for donor sheet rolls  230  not stored in the rotary rack  210  but to be used for image recording. Some representative cases are now described. If the image recording is executable with only the donor sheet rolls  230  stored in the rotary rack  210 , no exchange operation takes place but the image recording is executed along the order described in the color component information CI, as a matter of course.  
      (Case 1) Consider a case, represented in a rotary rack management table TBL 2   a  shown in  FIG. 4A , that donor sheet rolls  230  of the process colors are stored in sections  1  to  4  of the rotary rack  210 , while donor sheet rolls  230  of green and white are stored in the sections  5  and  6  respectively.  
      In this case, the color codes indicating all donor sheet rolls  230  stored in the rotary rack  210  match with the color codes described in the color component information CI. In other words, all donor sheet rolls  230  are employed for image formation, whereby the image transfer as to the first color component, i.e., cyan in this case, is performed without exchanging the donor sheet rolls  230  (NO at the step S 10 ). The control part CTL 2  reads out the exposure condition, for cyan registering the flag C 11  as “1”, associated with the color code c for cyan from the exposure condition setting table TBL 1  (step S 15 ), and executes image recording according to this exposure condition (step S 16 ). Thus, the control part CTL 2  reads the exposure condition as to the color component to be recorded on the basis of the color code C 12  so that the image recording under the optimum condition becomes executable without setting the exposure condition punctatim by the operator according to the color component. The image transferring recorder  1  transfers/records the image as shown in  FIG. 14  with reference to cyan.  
      First, the receiver sheet  140  is provided by delivering and cutting of a part of the revolute receiver sheet roll  130  through the function of the receiver sheet supply part  100 , and is wound on the drum  310  (step S 161 ). Then, rotation of the rotary rack  210  through the function of the donor sheet supply part  200  causes the donor sheet roll  230  of cyan to move to a position opposite to the donor sheet transport part  270 . The donor sheet  240  is provided by partially delivering and cutting of the revolute donor sheet roll  230 , and is wound on the drum  310  (step S 162 ).  
      After these preparations are completed, the control part CTL 2  transmits a preparation complete signal to the control part CTL 1  (step S 163 ). In response to this, the control part CTL 1  transfers the halftone image data DS as to cyan from the raster image processor  800  to the image transferring recorder  1  (step S 164 ). Keeping on rotating the drum  310 , the control part CTL 2  makes the recording head  350  emit the laser beam according to setting of the exposure condition for cyan as read out. The control part CTL 2  controls emitting on/off of the laser beam according to the received halftone image data DS thereby the image transferred/recorded from the sheet  240  for cyan to/on the receiver sheet  140  (step S 165 ). When the image recording of cyan is completed, the donor sheet  140  of cyan is peeled from the drum  310  and discharged to the donor sheet recovery box  40  through the discharge part  400  (step S 166 ).  
      When image recording as to the color component of cyan is completed, the control part CTL 1  determines whether or not there are data for other color components to be recorded (step S 17 ). In case of the aforementioned example, transfer/recording about the six remaining color components must be executed so image recording is not terminated (NO at the step S 17 ) but shifts to transfer recording of the subsequent color component (magenta). Thus, returning to the step S 10 , the control part CTL 2  determines necessariness/unnecessariness of exchange of the donor sheet roll  230  again.  
      At this point of time, the donor sheet roll  230  of cyan has been spent while the donor sheet roll  230  of violet to be finally employed for transfer is not yet stored. Therefore, it follows that the control part CTL 2  rotates the rotary rack  210  for locating the donor sheet roll  230  of cyan on the exchange position P 12  (step S 11 ). In association with this, the control part CTL 2  makes the display operation part  600  display a message for requesting the operator to exchange the donor sheet roll  230  of cyan with the donor sheet roll  230  of violet (step S 12 ). When the display operation part  600  displays this message, the operator opens the lid  12  for exchanging the donor sheet roll  230  of cyan located on the exchange position P 12  with the donor sheet roll  230  of violet (step S 13 ). After exchanging the donor sheet roll  230 , the operator operates the display operation part  600  for updating the description contents of the rotary rack management table TBL 2 . In other words, the operator writes in the rotary rack management table TBL 2  that the section  1  of the rotary rack  210  stores violet (step S 14 ). Thus, the color components of the donor sheet rolls  230  stored in the rotary rack  210  are correctly grasped subsequently, by referring to the rotary rack management table TBL 2 .  
      While successively recorded images of magenta, yellow, . . . similarly to the above, all donor sheet rolls  230  employed for image recording are already stored and hence successive image recording as to the respective color components is performed without exchange processing. At this time, the exposure conditions as to the respective color components previously registered in the exposure condition setting table TBL 1  is referable, whereby the operator may not set the exposure conditions every image recording as to a new color component.  
      (Case 2) Consider a case, represented in a rotary rack management table TBL 2   b  shown in  FIG. 4B , that the donor sheet rolls  230  of the process colors are stored in the section  1  to  4  of the rotary rack  210  and donor sheet rolls  230  of orange and white are stored in the sections  5  and  6  respectively. In this case, the color code s 1  does not match with the color codes described in the color component information CI among the color codes of the donor sheet rolls  230  stored in the rotary rack  210 . In other words, the donor sheet roll  230  of orange is unnecessary for image recording to be performed. Therefore, this donor sheet roll  230  is subjected to exchange at first (YES at the step S 10 ). The control part CTL 2  determines to first exchange the donor sheet roll  230  of green corresponding to the color code s 2 , for that color code to be firstly subjected to image recording in the color codes s 2  and s 16  which are both described in the color component information CI but undescribed in the rotary rack management table TBL 2 . Consequently, the control part CTL 2  rotates the rotary rack  210  for locating the donor sheet roll  230  of orange on the exchange position P 12  (step S 11 ) and requests the display operation part  600  to display that the operator must exchange the donor sheet roll  230  located on the exchange position with the donor sheet roll  230  of green (step S 12 ). When the operator terminates this exchange operation and an update operation for the rotary rack management table TBL 2  (steps S 13  and S 14 ), image recording about the first color component, i.e., cyan is performed similarly to the case 1 (steps S 15  and S 16 ).  
      After completion of image recording of cyan, the donor sheet roll  230  of cyan is exchanged with the donor sheet roll  230  of violet and subsequent image recording is continued.  
      (Case 3) Consider a case, represented in a rotary rack management table TBL 2   c  shown in  FIG. 4C , that the donor sheet rolls  230  of the process colors are stored in the sections  1  to  4  of the rotary rack  210  and donor sheet rolls  230  of orange and silver are stored in the sections  5  and  6  respectively. In this case, the color codes s 1  and s 7  do not match with the color codes described in the color component information CI among the color codes of the donor sheet rolls  230  stored in the rotary rack  210 . In other words, the donor sheet rolls  230  of orange and silver are unnecessary for image recording to be performed. Therefore, these donor sheet rolls  230  must be exchanged (YES at the step S 10 ).  
      In this case, the control part CTL 2  determines to first exchange the donor sheet roll  230  of green corresponding to the color code s 2  with the donor sheet roll  230  of orange or silver, for that color code to be firstly subjected to image recording among the color codes s 2 , s 11  and s 16  which are all described in the color component information CI but undescribed in the rotary rack management table TBL 2 , similarly to the case 2. When there are a plurality of donor sheet rolls  230  to be exchanged, for example, it is assumed that the control part CTL 2  makes control to preferentially exchange the donor sheet rolls  230  stored in the section having the minor section number. In this case, the donor sheet  230  of orange (stored in the section No. 5) is given preference over that of silver (stored in the section No. 6). Therefore, the control part CTL 2  determines to exchange the donor sheet roll  230  of orange with the donor sheet roll  230  of green. When the operator completes to exchange the donor sheet roll  230  of orange arranged on the exchange position P 12 , the control part CTL 2  rotates the rotary rack  210  thereby moving the donor sheet roll  230  of silver to the exchange position P 12 . Then, the control part CTL 2  makes the display operation part  600  display a message for requesting the operator to exchange the donor sheet roll  230  located on the exchange position P 12  with the donor sheet roll  230  of white, thereby prompting the operator to exchange the donor sheet roll  230 . When the donor sheet roll  230  of white is stored in the rotary rack  210 , image recording about cyan, storing the donor sheet roll  230  of violet, and image recording about magenta are successively performed thereafter and the remaining colors similarly to the case 1.  
      In each of the cases 1 to 3, image recording process terminates when completing image recording as to violet (YES at the step S 17 ). The receiver sheet  140  is peeled from the drum  310  and discharged to the tray  50  through the discharge part  400  (step S 18 ). The obtained receiver sheet  140  is supplied to the laminator  900 , which in turn transfers the recorded image to a printing paper.  
      According to the first embodiment, it is the control part CTL 2  in each of the aforementioned cases 1 to 3 that determines which ones of the donor sheet rolls  230  stored in the rotary rack  210  are to be exchanged, whereby the operator may not make this determination but may simply exchange the donor sheet roll  230  located on the exchange position P 12  with the donor sheet roll  230  displayed on the display operation part  600  and input information indicating which donor sheet roll  230  has been stored. Further, the operator may not set the exposure condition in image recording as to each color component either. Therefore, the operator can perform operations without special knowledge about color separation and image recording.  
      While the control part CTL 2  of the image transferring recorder  1  decides the donor sheet roll  230  to be detached from the rotary rack  210  for exchange in the above description, the operator may alternatively decide this donor sheet roll  230 . In this case, the operator can decide the donor sheet roll  230  to be detached from the rotary rack  210  through his/her manual operation in consideration of the workflow.  
      Case of Performing Pseudocolorization  
      In case that inks employed for regular press are specific ones or no donor sheet rolls  230  capable of reproducing colors expressed by these inks are prepared, the color table TBL 3  as well as the exposure condition setting table TBL 1  have no registration about the color components corresponding to the color codes described in the color component information CI at the step S 5  (NO at the step S 5 ). In this case, it is impossible to perform image recording as to the unregistered color components though color separation is executed in the data interpretation part  810 , so it is required to perform pseudocolorization processing of reproducing the unregistered color components substitutionally with registered color components (step S 6 ).  
      For example, consider the case that color separation for regular press is set up for printing with inks of seven colors of cyan (C), magenta (M), yellow (Y), black (K), red (R), white (W) and violet (V) but no donor sheet roll  230  of red is prepared and no registration about it exists in the exposure condition setting table TBL 1  and the color table TBL 3 . In this case, the data interpretation part  810  creates first color separation data DCS 1  expressing respective color component images of cyan (C), magenta (M), yellow (Y), black (K), red (R), white (W) and violet (V) from the layout data DL (step S 3 ) and creates color component information CI indicating that these color components are included (step S 4 ). The control part CTL 1  compares this color component information CI with the storage contents of the color table TBL 3 . Since the exposure condition setting table TBL 1  and the color table TBL 3  have no registration about the donor sheet roll  230  of red, the control part CTL 1  determines that pseudocolorization must be performed as to red and requests the correction processing part  820  to perform pseudocolorization as to the color component of red in advance of correction processing such as color matching of the first color separation data DCS 1 . The correction processing part  820  makes color separation of the first color separation data DCS 1  as to the red component into color separation data of the remaining six color components employed for printing. The correction processing part  820  further superposes six color component image data obtained by this color separation on the remaining six first color separation data DCS 1  for generating pseudocolorized first color separation data DCS 1 . Then, the correction processing part  820  performs correction processing such as color matching on the six pseudocolorized first color separation data DCS 1 . The six pseudocolorized first color separation data DCS 1  subjected to correction processing such as color matching are outputted to the screening processing part  830  as second color separation data DCS 2 .  
      The color component information CI to be transferred to the image transferring recorder  1  is corrected from information indicating color components of seven colors to information indicating respective color components of the six colors (C, M, Y, K, W and V) other than red (R) in response to the results of the aforementioned pseudocolorization processing. Subsequent processing is performed similarly to the above.  
      According to the first embodiment, the control part CTL 1  determines necessariness/unnecessariness of pseudocolorization. If the control part CTL 1  determines that pseudocolorization must be performed, the correction processing part  820  subsequently performs it in effect and hence the operator may neither determine necessariness/unnecessariness of pseudocolorization nor specify the color for pseudocolorization. Thus, he/she can perform operations without detailed knowledge about color separation and image recording.  
      In the case of the first embodiment, however, the donor sheet rolls  230  can be exchanged at need as hereinabove described, and hence it is interpretable that the potentiality of requiring pseudocolorization itself is reduced as compared with prior art so far as the donor sheet rolls  230  are previously sufficiently prepared and the exposure conditions therefor etc. are registered.  
      In the image recording system  100  according to the first embodiment, as hereinabove described, the donor sheet rolls  230  stored in the rotary rack  210  can be exchanged at need, whereby the upper limit of the number of color components formable on a single receiver sheet  140  is not limited to the number of the donor sheet rolls  230  simultaneously storable in the rotary rack  210 . Therefore, a proof image finished in fidelity to image recording in regular press can be obtained so far as donor sheet rolls  230  corresponding to inks employed in regular press are prepared. Further, image recording as to a large number of color components is enabled without increasing the number of the donor sheet rolls  230  storable in the rotary rack  210 , whereby transfer processing is allowed as to a larger number of color components without increasing the size of the image transferring recorder  1 .  
      In addition, it is automatically determined which donor sheet rolls  230  are to be exchanged in such exchange, whereby the operator may not previously grasp which donor sheet rolls  230  must be exchanged among the donor sheet rolls  230  stored in the rotary rack  210 . The operator can perform operations without advanced knowledge or skill since he/she may simply exchange the donor sheet roll  230  assumed to be the object of exchange with a specified donor sheet roll  230 . Further, the exposure condition setting table TBL 1  previously has registration about the exposure conditions as to the respective donor sheet rolls  230 , whereby the operator may not set the exposure conditions punctatim following exchange.  
      Further, necessariness/unnecessariness of pseudocolorization and specification of the objective color component on it are automatically determined, whereby the operator may be required neither determination nor deep knowledge and skill as to this processing either.  
     Second Embodiment  
      In the aforementioned first embodiment, the control part CTL 1  of the raster image processor  800  transfers the color component information CI to the control part CTL 2  of the image transferring recorder  1  thereby simultaneously supplying information as to all color components to the control part CTL 2 . Alternatively, the control part CTL 1  may supply color component information to the control part CTL 2  punctatim in the order that images are to be recorded in the image transferring recorder  1 .  FIG. 15  illustrates a procedure of this case in a second embodiment of the present invention. Referring to  FIG. 15 , processing in steps S 31  to S 38  is identical to that in the steps S 1  to S 8  shown in  FIG. 12 , and hence redundant description is omitted.  
      Following a step S 39 , processing is sequentially performed as to an i-thly image-recorded color component. In a case of recording images as to seven colors of cyan (C), magenta (M), yellow (Y), black (K), green (G), white (W) and violet (V) in this order, for example, a color code (c) for a color component of i=1, i.e., cyan, is transferred to an image transferring recorder  1  as color component information (steps S 40  and S 41 ). On the image transferring recorder  1 , it is determined whether a rotary rack management table TBL 2  has a registration of the color code (c) as to the transferred color component or not, i.e., whether a rotary rack  210  stores a donor sheet roll  230  of cyan at this point of time or not (step S 41 ). Since no roll exchange is necessary if the rotary rack  210  stores the donor sheet roll  230  of cyan (NO at the step S 41 ), image recording is performed (steps S 46  and S 47 ). The processing for image recording at the steps S 46  and S 47  is identical to that in the first embodiment, and hence redundant description is omitted. If the rotary rack  210  stores no donor sheet roll  230  of cyan (YES at the step S 41 ), on the other hand, any donor sheet roll  23  already stored in the rotary rack  210  is moved to an exchange position P 12  and an instruction for exchanging the same to the donor sheet roll  230  of cyan is displayed on a display operation part  600  (steps S 42  and S 43 ). At this time, the donor sheet roll  230  to be exchanged is arbitrarily set, a mode of preferentially setting not a frequently used donor sheet roll  230  of a process color but a donor sheet roll  230  of a special color as the object of exchange or the like is considerable. When such exchange is completed, image recording is performed similarly to the above (steps S 46  and S 47 ).  
      When the image recording as to the certain i-th color component is completed, a signal of this purport is supplied to the control part CTL 1 , which in turn determines whether or not recording as to another color component must be performed (step S 49 ). For example, image recording as to magenta must be performed after terminating image recording as to cyan in the above case, whereby, returning to the step S 40 , color component information as to magenta is transferred as that of the second color component. Thereafter processing as to all color components is similarly repeated, whereby it follows that a proof image is formed on a receiver sheet  140 . When all recording is terminated (YES at a step S 48 ), the receiver sheet  140  is discharged to a tray  50  (step S 50 ).  
      Also in the second embodiment, any donor sheet roll  230  stored in the rotary rack  210  is enabled to exchange at need, whereby the upper limit of the number of color components formable on a single receiver sheet  140  is not limited to the number of the donor sheet rolls  230  simultaneously storable in the rotary rack  210 . Therefore, a proof image finished in fidelity to image recording in regular press can be obtained so far as donor sheet rolls  230  corresponding to inks employed in regular press are prepared. Further, image recording as to a large number of color components is enabled without increasing the number of the donor sheet rolls  230  storable in the rotary rack  210 , whereby transfer processing is allowed as to a larger number of color components without increasing the size of the image transferring recorder  1 .  
      In addition, necessariness/unnecessariness for exchange of each donor sheet roll  230  is automatically determined in such exchange, whereby the operator may not previously grasp which donor sheet roll  230  is to be exchanged from among the donor sheet rolls  230  stored in the rotary rack  210 . Thus, the operator can perform operations without advanced knowledge or skill since he/she may simply exchange the donor sheet roll  230  assumed to be the object of exchange with a specified donor sheet roll  230 . Further, the exposure condition setting table TBL 1  previously has registration about the exposure conditions as to the respective donor sheet rolls  230 , whereby the operator may not set the exposure conditions punctatim following exchange. Alternatively, the operator him/herself may specify the donor sheet roll  230  to be exchanged.  
      &lt;Modifications&gt; 
      While the raster image processor  800  holds the color table TBL 3  so that the control part CTL 1  refers to the same in the aforementioned embodiment, the control part CTL 1  may alternatively directly refer to the exposure condition setting table TBL 1 . In this case, the raster image processor  800  may not hold the color table TBL 3 .  
      While a donor sheet roll  230  stored in the rotary rack  210  unnecessary for image recording is preferably exchanged in the first embodiment, it may be alternatively exchanged after performing image recording performable with already stored donor sheet rolls  230  for performing subsequent image recording.  
      While the control part CTL 2  of the image transferring recorder  1  obtains the color component information CI from the raster image processor  800  for performing image recording as to each color component, with necessariness/unnecessariness of roll exchange determined in the first embodiment, the control part CTL 1  of the raster image processor  800  may alternatively receive the description contents of the rotary rack management table TBL 2  from the image transferring recorder  1  for comparing/collating the color component information CI with the description contents and supplying information as to necessariness/unnecessariness of roll exchange to the image transferring recorder  1  on the basis the results of this comparison/collation.  
      While pseudocolorization is implemented by performing color separation with the remaining color components employed for regular press in the aforementioned embodiments, pseudocolorization may alternatively be performed with a color component not used in regular press but registered in the exposure condition setting table TBL 1 , i.e., with remaining color components for which a donor sheet roll  230  are prepared. In this case, reproducibility for a halftone shape in a proof image as to the color component employed in regular press is more improved than the case of performing pseudocolorization in the aforementioned embodiment by not employing the color component employed for regular press for pseudocolorization.  
      While the invention has been shown and described in detail, the foregoing description is in all aspects illustrative and not restrictive. It is therefore understood that numerous modifications and variations can be devised without departing from the scope of the invention.