Patent Publication Number: US-9840089-B2

Title: Printer, printing system, and card manufacturing method

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority under 35 U.S.C. §119 from Japanese Patent Application No. 2015-136660, filed on Jul. 8, 2015, the entire contents of which are incorporated herein by reference. 
     BACKGROUND 
     The present disclosure relates to a printer and printing system which print a glossy color image on a print matter using metal ink, and a method of manufacturing a card including a glossy color image printed using metal ink. 
     As such a printer, a retransfer device is widely used which sublimates or fuses ink of an ink ribbon with a thermal head, and transfers the ink to form an image on a transfer body. The printer again transfers and prints the image transferred to the transfer body onto a recording medium such as a card. Japanese Patent No. 4337582 describes such a retransfer device. 
     In the retransfer device, the ink ribbon includes ink layers of four colors, including: yellow (Y), magenta (N), cyan (c), and black (B), for example. The ink of each ink layer is sequentially transferred and superimposed on the transfer body to form a non-glossy color image. The formed image is again transferred on another transfer body for printing, so that the non-glossy color image is formed on the transfer body. 
     The ink ribbon can be an ink ribbon including an ink layer of metal ink showing metallic gloss instead of the black ink layer, or in some cases as an ink layer of the fifth color. The metal ink is frequently referred to as silver ink. There is a used technique to form a glossy color image on the surface of the transfer body, such as a card, by performing similar transfer and retransfer printing using an ink ribbon having an ink layer of metal ink. 
     The technique to form a glossy color image is described in Japanese Patent No. 3373714. 
     Hereinafter, such non-glossy and glossy color images formed on a transfer body are referred to as formed images. The object on which an image is to be formed by transfer printing is referred to as a transfer body. 
     SUMMARY 
     Y, M, and C color inks (hereinafter referred to as color inks) of the ink ribbon are sublimation inks that transmits light. 
     The sublimation ink is suitable for forming a color image of high resolution. By using the sublimation ink, the lightness and darkness of an image are controlled without reducing the number of dots of the image, so that transfer of multiple shades of color can be implemented. 
     On the other hand, the metal ink is light-blocking fusion ink that contains metal flakes of aluminum or the like to provide a glossy appearance. 
     The lightness and darkness of metal ink cannot be controlled without reducing the number of dots of the image. Metal ink basically provides only two shades, whether the ink is transferred or not. 
     In order to form a natural image with gloss visually recognized according to the shades of color inks, the following method is examined: data of a raw image to be transferred is subjected to dithering into glossy image data, and metal ink of the ink ribbon is transferred to the transfer body according to the glossy image data. 
     The glossy appearance in the formed image is obtained by metal ink of the formed image that (approximately) specularly reflects light from a light source with a high directivity. 
     When the transfer body to which an image is to be retransferred transmits light, metal ink is placed closest to the transfer body, and each color ink is superimposed on the metal ink. 
     With the aforementioned configuration, light incident on the part on which the metal ink is transferred (the metal ink transferred part) is (approximately) regularly reflected on the metal ink which is placed at the deepest position. The reflected light exits through the color inks superimposed on the metal ink. When seen in the outgoing direction of the reflected light, the metal ink transferred part is seen in a glossy color corresponding to the color inks, through which the reflected light is transmitted. 
     The light incident on the part on which no metal ink is transferred (the metal ink non-transferred part) reaches the material surface of the transfer body, and is diffusely reflected. 
     Therefore, when the density of the formed image by color inks in the metal ink transferred part is the same as that in the metal ink non-transferred part, the brightness and darkness of the formed image looks different depending on the angle of sight, with respect to the transfer body. To be specific, at a certain angle of sight, light reflected on the metal ink is seen, and the metal ink transferred part looks brighter in the metal ink transferred part than in the metal ink non-transferred part. At another angle of sight, the light reflected on the metal ink is not seen, and the metal ink transferred part looks darker. 
     That is, the metal ink transferred part has a difference in gloss depending on the angle of sight when it looks brighter and when it looks darker than the metal ink non-transferred part. 
     The difference in gloss is as follows when dithering is performed for the raw image data, so that the density of an image formed with metal ink is proportional to that of an image formed by color ink, for example. 
     The difference in gloss in the metal ink transferred part can be recognized, but is comparatively less noticeable in a low lightness region (a high density region) of the formed image. 
     In a high lightness region (a low density region), the colors of color ink are than and bright, and the metal ink transferred part is scattered in the form of dots due to the dithering. 
     Accordingly, in the high lightness region of the formed image, scattered dark-looking dots of the metal ink transferred part are dominantly recognized in the bright region depending on the angle of sight, so that the formed image has poor quality. There is a demand for improving this problem. 
     A first aspect of the embodiments provides a printer including: an input unit configured to receive first image data corresponding to a first print image of a first ink; a density acquisition unit configured to acquire a density value of each pixel included in the first image data; a glossy image density decision unit configured to set a gloss density value which specifies the density of gloss to be added to the pixel to the minimum possible value of the gloss density value, when the density value of the pixel is less than a predetermined value, and sets the gloss density value to a value larger than the minimum possible value, when the density value of the pixel is equal to or greater than the predetermined value; a dithering processor configured to perform dithering based on the set gloss density value to create second image data corresponding to a second print image of a second glossy ink; and a printing unit configured to superimpose and print the first and second print images on a print body to form a glossy image on the print body. 
     A second aspect of the embodiments provides a printing system including: a printer; and a printer driver configured to send image data to the printer, wherein the printer driver includes: an input unit configured to receive first image data corresponding to a first print image of a first ink; a density acquisition unit configured to acquire a density value of each pixel included in the first image data; a glossy image density decision unit configured to set a gloss density value which specifies the density of gloss to be added to the pixel to the minimum possible value of the gloss density value, when the density value of the pixel is less than a predetermined value, and to set the gloss density value to a value larger than the minimum possible value, when the density value of the pixel is equal to or greater than the predetermined value; and a dithering processor configured to perform dithering based on the set gloss density value to create second image data corresponding to a second print image of a second glossy ink; and the printer includes a printing unit configured to superimpose and print the first and second print images on a print body to form a glossy image on the print body. 
     A third aspect of the embodiments provides a method of manufacturing a card, including: acquiring a density value of each pixel included in first image data corresponding to a first print image of a first ink; setting a gloss density value which specifies the density of gloss to be added to the pixel to the minimum possible value of the gloss density value, when the density value of the pixel is less than a predetermined value; setting the gloss density value to a value, larger than the minimum possible value, when the density value of the pixel is equal to or greater than the predetermined value; performing dithering based on the set gloss density value to create second image data corresponding to a second print image of a second glossy ink; and superimposing and printing the first and second print images on a card to manufacture a card with a glossy image printed thereon. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram illustrating a printer PR as Example 1 of a printer according to at least one embodiment. 
         FIG. 2  is a block diagram illustrating the configuration of the printer PR. 
         FIG. 3  is a plan view and a side view illustrating an ink ribbon  11  used in the printer PR. 
         FIG. 4  is a plan view and a side view illustrating an intermediate transfer film  21  used in the printer PR. 
         FIG. 5  is a view illustrating a pressure contact between the ink ribbon  11  and intermediate transfer film  21  by a thermal head  16  of the printer PR. 
         FIG. 6  is a diagram illustrating the thermal head  16 . 
         FIG. 7  is a diagram illustrating the data structure of each pixel in color image data SN 1 . 
         FIG. 8  is a diagram illustrating R, G, and B values of a pixel Qa. 
         FIG. 9  is a flowchart illustrating the operation procedure of a glossy image density decision unit CT 2   b.    
         FIG. 10  is a diagram illustrating R, G, and B values of a pixel Qb. 
         FIG. 11  is a diagram illustrating the data structure of each pixel in color image data SN 1  and glossy image data SN 2 . 
         FIG. 12  is a first diagram illustrating an operation to transfer and form an intermediate image P on the intermediate transfer film  21 . 
         FIG. 13  is a second diagram illustrating the operation to transfer and form the intermediate image P on the intermediate transfer film  21 . 
         FIG. 14  is a third diagram illustrating the operation to transfer and form the intermediate image P on the intermediate transfer film  21 . 
         FIG. 15  is a fourth diagram illustrating the operation to transfer and form the intermediate image P on the intermediate transfer film  21 . 
         FIG. 16  is a fifth diagram illustrating the operation to transfer and form the intermediate image P on the intermediate transfer film  21 . 
         FIG. 17  is a schematic cross-sectional view illustrating the intermediate image P formed on the intermediate transfer film  21 . 
         FIG. 18  is a plan view illustrating the intermediate transfer film  21  after the intermediate image P is retransferred. 
         FIG. 19  is a schematic cross-sectional view illustrating a card  31  on which an image Pc is formed by retransfer of the intermediate image P. 
         FIG. 20  is a schematic cross-sectional view illustrating light reflected on metal ink in the image Pc formed on the card  31 . 
         FIG. 21  is a diagram illustrating a glossy image Ps by the glossy image data SN 2 . 
         FIG. 22  is a block diagram illustrating the configuration of a printing system SY of Example 2. 
         FIG. 23  is a group of diagrams illustrating modifications of a method of creating the glossy image data SN 2 . 
     
    
    
     DETAILED DESCRIPTION 
     First, a description is given of a printer PR as Example 1 of a printer of an embodiment according to the present invention with reference to  FIGS. 1 to 21 . 
     Example 1 
     The printer PR of Example 1 is a retransfer printer, a so-called card printer, for example. 
     As illustrated in  FIG. 1 , the printer PR includes a casing PRa, a transfer device  51 , and a retransfer device  52 . The transfer and retransfer devices  51  and  52  are accommodated in the casing PRa. The transfer and retransfer devices  51  and  52  constitute a printing unit. 
     The printer PR transfers ink of the ink ribbon  11  to an intermediate transfer film  21  as a transfer body (a printed matter) to form an image in the transfer device  51 . The printer PR further retransfers the image transferred and formed on the intermediate transfer film  21  to a card material  31   a  as another transfer body, thus producing a card  31  with the image printed thereon. 
     The transfer device  51  is provided with a supply reel  12  and a take-up reel  13  for the ink ribbon  11 , which are detachably attached to the transfer device  51 . 
     The attached supply and take-up reels  12  and  13  are driven and rotated by driving motors M 12  and M 13 , respectively. The rotation speeds and directions of the motors M 12  and M 13  are controlled by a controller CT, which is provided for the printer PR. 
     The ink ribbon  11  is guided by the plural guide shafts  14 , and is laid along a predetermined travel path between the supply and take-up reels  12  and  13 . 
     In the middle of the travel path of the ink ribbon  11 , an ink ribbon sensor  15  for cueing is provided. 
     The ink ribbon sensor  15  detects a cue mark  11   d  (refer to  FIG. 3 ) of the ink ribbon  11 , and sends ribbon mark detection information J 1  (refer to  FIG. 2 ) to the controller CT. 
     As illustrated in  FIG. 3 , the ink ribbon  11  includes a ribbon base  11   a , an ink layer  11 Y of yellow ink, an ink layer  11 M of magenta ink, an ink layer  11 C of cyan ink, and an ink layer  11 S metal ink providing metallic gloss. The ink layers  11 Y,  11 M,  11 C, and  11 S are formed on one surface of the ribbon base  11   a . The ink ribbon  11  is described in detail later. In the following description, each of the yellow, magenta, and cyan inks is referred to as a color ink. 
     In  FIG. 1 , between the ink ribbon sensor  15  and the take-up reel  13  on the travel path of the ink ribbon  11 , a thermal head  16  is provided. 
     The thermal head  16  contacts and separates from the surface (refer to  FIG. 3B ) of the laid ink ribbon  11  on the ribbon base  11   a  side (in the direction of arrow Da of  FIG. 5 ). 
     The contacting and separating operation of the thermal head  16  is executed by a head contact and separation driver D 16 , under control of the controller CT. 
     The transfer device  51  is provided with a supply reel  22  and a take-up reel  23  for the intermediate transfer film  21 , which are detachably attached to the left of the loaded ink ribbon  11  in  FIG. 1 . 
     The attached supply and take-up reels  22  and  23  are driven and rotated by the driving motors M 22  and M 23 , respectively. The rotation speeds and directions of the motors M 22  and M 23  are controlled by the controller CT. 
     The intermediate transfer film  21  is guided by the plural guide shafts  24 , and is laid along a predetermined travel path between the supply and take-up reels  22  and  23 . 
     In the middle of the travel path of the intermediate transfer film  21 , a frame mark sensor  25  for cueing is provided. The frame mark sensor  25  detects frame marks  21   d  (refer to  FIG. 4 ) of the intermediate transfer film  21 , and sends frame mark detection information J 2  (refer to  FIG. 2 ) to the controller CT. 
     The intermediate transfer film  21  transmits light. The frame mark sensor  25  is an optical sensor, for example. The frame marks  21   d  are formed so as to block light, and the frame mark sensor  25  detects the frame marks  21   d  based on the difference between light being transmitted and light being blocked. 
     Between the frame mark sensor  25  and supply reel  22  on the travel path of the intermediate transfer film  21 , a platen roller  26 , which is driven and rotated by a motor M 26 , is provided. The rotation speed and direction of the motor M 26  are controlled by the controller CT. 
     As illustrated in  FIG. 5 , the thermal head  16  contacts and separates from the ink ribbon  11  through the contacting and separating operation by the head contact and separation driver D 16 . The thermal head  16  and platen roller  26  need to relatively contact and separate from each other. The platen roller  26  may be configured to contact and separate from the ink ribbon  11 . 
     To be specific, the thermal head  16  moves between a pressure contact position (which is illustrated in  FIG. 5 ) and a separation position (which is illustrated in  FIG. 1 ). When being at the pressure contact position, the thermal head  16  presses the ink ribbon  11  against the platen roller  26 , to bring the intermediate transfer film  21  and ink ribbon  11  into a pressure contact between the thermal head  16  and platen roller  26 . When being at the separation position, the thermal head  16  is separated from the ink ribbon  11 . A later-described transfer is performed while the thermal head  16  is located at the pressure contact position. 
     The ink ribbon  11  and intermediate transfer film  21  are configured to be independently rewound by the take-up reels  13  and  23 , and rewound by supply reels  12  and  22  through operations of the motors M 12  and M 13 , and motors M 22  and M 23 , respectively, while the thermal head  16  is located at the separation position. 
     The ink ribbon  11  and the intermediate transfer film  21 , being in close contact with each other, move together toward the supply reels  13  and  23 , or the take-up reels  12  and  22 . The movement is executed by rotation of the supply reels  12  and  22 , the take-up reels  13  and  23 , and the platen roller  26  which are driven by the motors M 12 , M 13 , M 22 , M 23 , and M 26  under control of the controller CT. 
     As illustrated in  FIGS. 1 and 2 , the printer PR includes the controller CT, the storage unit MR, and the communication unit  37 . The communication unit  37  functions as an input unit, through which the printer PR received data transmitted externally and the like. The controller CT includes a central processing unit (CPU) CTa and an image data transmitter CTb. 
     As illustrated in  FIG. 2 , the image data transmitter CTb includes a color image data transmitter CT 1  and a glossy image data transmitter CT 2 . 
     The glossy image data transmitter CT 2  includes a color image density acquisition unit CT 2   a  (also referred to as a density acquisition unit CT 2   a ), a glossy image density decision unit CT 2   b , and a dithering processor CT 2   c.    
     The controller CT is supplied with transfer image information J 3  (refer to  FIG. 2 ) through the communication unit  37  from the external data device  38 . The transfer image information J 3  includes color image data SN 1  as image data of a non-glossy color image. The supplied color image data SN 1  is stored in the storage unit MR. 
     The color image data transmitter CT 1  generates image data SN 1   y  of an image to be transferred with yellow ink in the ink layer  11 Y, image data SN 1   m  of an image to be transferred with magenta ink in the ink layer  11 M, and image data SN 1   c  of an image to be transferred with cyan ink of the ink layer  11 C. 
     The color image data transmitter CT 1  sends the image data SN 1   y , SN 1   m , and SN 1   c  as color image data SN 1 A to the thermal head  16 . 
     The sublimation of each color ink can be adjusted by the amount of heat given by the thermal head  16 . The lightness and darkness of the transferred image can be represented by density levels. 
     The glossy image data transmitter CT 2  creates glossy image data SN 2  to be transferred with metal ink based on the color image data SN 1 , and sends the same to the thermal head  16 . The method of creating the glossy image data SN 2  is described later. 
     The image data transmitter CTb supplies the color image data SN 1 A for color inks and the glossy image data SN 2  for metal ink to the thermal head  16  at the proper timing, which are to be transferred to the transfer frame F (refer to  FIG. 4 , described later in detail) of the intermediate transfer film  21 . 
     The timing at which the color image data SN 1 A and glossy image data SN 2  are supplied is determined by the whole controller CT, based on the frame mark detection information J 2  and the like. 
     As illustrated in (a) and (b) of  FIG. 3 , the ink ribbon  11  includes the belt-shaped ribbon base  11   a  and ink layers  11   b , which are applied and formed on the ribbon base  11   a . The ink ribbon  11  includes four types of ink layers as the ink layers  11   b . The four types of ink layers are arranged in a predetermined order to constitute each ink group  11   b   1 . The ink groups  11   b   1  are applied repeatedly in the longitudinal direction of the ink ribbon  11  (in the direction of arrow DRa). 
     To be specific, the ink group  11   b   1  includes the ink layer  11 Y of yellow ink, the ink layer  11 M of magenta ink, the ink layer  11 C of cyan ink, and ink layer  11 S of metal ink, which are applied in this order in the longitudinal direction. 
     The yellow ink, magenta ink, and cyan ink are sublimation ink and transmit light. The metal ink is gray fusion ink, for example. The metal ink contains metal particles, or flakes, and is light impermeable. The metal is aluminum or silver, for example. 
     The metal ink transferred part formed on the transfer body by transfer of the metal ink (approximately) specularly reflects the incident light with a high directivity. The metal ink transferred part is visually recognized as a metallic glossy silver color. 
     In each ink layer  11 Y, a cueing mark  11   d  is formed at an end of the boundary with the adjacent ink layer  11 S of the metal ink. 
     The ink layers  11 Y,  11 M,  11 C, and  11 S have the same length La in the longitudinal direction. Pitch Lap of a group of the ink layers  11   b  is four times the length La. 
     The ink ribbon sensor  15  is positioned so that when the ink ribbon sensor  15  detects one of the cueing marks  11   d , the pressure contact position of the thermal head  16  corresponds to the position of the leading edge of the ink layer  11 Y in the travel direction. That is, the travel path length from the pressure contact position to the position of detection by the ink ribbon sensor  15  is an integral multiple of the pitch Lap. 
     As illustrated in (a) and (b) of  FIG. 4 , the intermediate transfer film  21  includes a belt-shaped film base  21   a , a release layer  21   b , and a transfer image receiving layer  21   c . The release layer  21   b  and the transfer image receiving layer  21   c  are laid on the film base  21   a.    
     The film base  21   a  has the same width as the ribbon base  11   a  of the ink ribbon  11 . In the film base  21   a  or the transfer image receiving layer  21   c , the frame marks  21   d  are repeatedly formed with a predetermined pitch Lb in the longitudinal direction (in the direction of arrow DRb). Each frame mark  21   d  is formed across the entire width. The pitch Lb is equal to the length La in the ink ribbon  11  (Lb=La). 
     The transfer frames F are regions partitioned at regular intervals of the pitch Lb in the intermediate transfer film  21 . Hereinafter, the transfer frames F are referred to as the frames F. The frame marks  21   d  are provided at boundaries of the frames F to partition the frames F so that the plural frames F are arranged side by side in the longitudinal direction of the intermediate transfer film  21 . 
     The frame mark sensor  25  (refer to  FIG. 1 ) is positioned so that when the frame mark sensor  25  detects one of the frame marks  21   d , the pressure contact position of the thermal head  16  corresponds to the position of the leading edge of the frame mark  21   d  in the travel direction. That is, the travel path length from the pressure contact position to the position of detection by the frame mark sensor  25  is an integral multiple of the pitch Lb. The travel path length is four times the pitch Lb, for example. 
     In the transfer device  51 , the intermediate transfer film  21  and the ink ribbon  11  are laid so that the transfer image receiving layer  21   c  directly faces the ink layer  11   b , as illustrated in  FIG. 5 . 
     The transfer image receiving layer  21   c  receives and fixes the inks of the ink layers  11 Y,  11 W, and  11 C, which are heated and sublimated, and the metal ink of the ink layer  11 S, which is heated and fused. 
     When the thermal head  16  is in pressure contact with the ink ribbon  11  as illustrated in  FIG. 5 , the ink of the ink layer  11   b , which is pressed against the transfer image receiving layer  21   c , is transferred to form and print an image in the transfer image receiving layer  21 . 
     In the transfer process, the color inks of the ink layers  11 Y,  11 M, and  11 C are transferred according to a heating pattern corresponding to the color image data SN 1 A supplied to the thermal head  16 . The metal ink of the ink layer  11 S is transferred according to a heating pattern, corresponding to the glossy image data SN 2  supplied to the thermal head  16 . 
     The transfer device  51 , described above in detail, is configured so that the ink ribbon  11  and the intermediate transfer film  21  loaded by the user can move in the longitudinal direction, while being brought into contact with each other by the thermal head  16 . 
     As illustrated in  FIG. 6 , the thermal head  16  includes n (n is an integer equal to or greater than 2) heating resistors  16   a  (# 1  to #n) arrayed in the width direction of the ink ribbon  11 . The thermal head  16  includes a head driver  16   b , which energizes the plural heating resistors  16   a  independently in accordance with the color image data SN 1  and glossy image data SN 2 . The heating resistors  16   a  include  300  heating resistors arrayed side by side per 1 inch, for example. 
     The head driver  16   b  energizes each of the plural heating resistors  16   a , based on the color image data SN 1 A used for transfer of the color ink, and the glossy image data SN 2  used for transfer of the metal ink, which are transmitted from the image data transmitter CTb. 
     An image to be formed does not use every n of the heating resistors  16   a , and typically uses m of the heating resistors  16   a  (m is an integer equal to or greater than 1, and m&lt;n). The m heating resistors  16   a  are adjacent to each other, and margins must be left at both ends in the direction that the resistors  16   a  are arranged. 
     That is, (n−m) of the plural heating resistors  16   a  arranged side by side are left as the margins and are not used in image formation. The m of the heating resistors  16   a  are selected from the n heating resistors  16   a  so as to be successive other than at least the heating resistor  16   a  located at an end. 
     An image is formed with m×LNa (width×length) dots on the intermediate transfer film  21  as an image formed body. Herein, LNa indicates the number of lines of the image to be transferred in the longitudinal direction. The number LNa corresponds to the number of lines that can be energized independently. 
     When the printer PR forms an image of 300 dpi on a card with the external dimensions of 86 mm×54 mm as a transfer body for retransfer, m is about 1000, and LNa is about 600. 
     The transfer device  51  moves the ink ribbon  11  and the intermediate transfer film  21 , which are in close contact with each other while properly energizing each heating resistor  16   a  of the thermal head  16 , based on the color image data SN 1 A at transfer of the color inks, and based on the glossy image data SN 2  at transfer of the metal ink. The transfer device  51  thus transfers and superimposes the inks of the ink layers  11   b  of the ink ribbon  11  in the same frame F of the transfer image receiving layer  21   c  of the intermediate transfer film  21 . 
     Accordingly, a desired glossy color image is transferred to a frame F of the transfer image receiving layer  21   c . The details of this image-forming operation are described later. 
     Returning to  FIG. 1 , the printer PR includes the retransfer device  52 . The retransfer device  52  retransfers a part of the image formed in the transfer image receiving layer  21  of the intermediate transfer film  21  as the transfer body in the transfer device  51  to one of the card materials  31   a  as another transfer body to produce each card  31 . In  FIG. 1 , the card materials  31   a  and card  31 , which are being conveyed, are illustrated by thick lines. 
     The retransfer device  52  shares the controller CT with the transfer device  51 . The retransfer device  52  includes a retransfer unit ST 1 , a supply unit ST 2 , and a delivery unit ST 3 . The retransfer unit ST 1  is provided between the platen roller  26  and the take-up reel  23  on the travel path of the intermediate transfer film  21 . The supply unit ST 2  supplies the card materials  31   a  to the retransfer unit ST 1 . The delivery unit ST 3  delivers the cards  31  having passed through the retransfer unit ST 1 . 
     The retransfer unit ST 1  includes a heat roller  41  rotated by the motor M 41 , an opposite roller  42  provided opposite to the heat roller  41 , and a heat roller driver D 41 . The heat roller driver D 41  brings the heat roller  41  close to or away from the opposite roller  42 . 
     The supply unit ST 2  includes a reorientation unit ST 2   a , which sandwiches each card material  31   a  and rotates by 90 degrees so that the card material  31   a  is reoriented from the vertical position to the horizontal position. 
     The supply unit ST 2  includes a pick-up roller  33 . The pick-up roller  33  rotates so as to raise the rightmost ( FIG. 1 ) of the plural card materials  31   a , which are standing vertically in the stacker  32 . 
     The supply unit ST 2  includes a pair of feeding rollers  34 , and plural pairs of conveyance rollers  35 . The feeding rollers  34  sandwich and feed each card material  31   a , raised by the pick-up roller  33  to the reorientation unit ST 2   a , provided above the supply unit ST 2 . The conveyance rollers  35  feed the cards  31 , reoriented to the horizontal position by the reorientation unit ST 2   a  to the retransfer unit ST 1  in the left side. 
     The operation of the motor M 41  is controlled by the controller CT. The pick-up roller  33 , the feeding rollers  34 , and the conveyance rollers  35 , are driven and rotated by the unillustrated motors under control of the controller CT. 
     The retransfer device  52  reorients each card material  31   a , which is standing vertically, and is picked up from the stacker  32  in the supply unit ST 2  to the horizontal position in the reorientation unit ST 2   a . The retransfer device  52  then conveys and supplies the reoriented, card material  31   a  to the retransfer unit ST 1 . 
     In the retransfer unit ST 1 , the card material  31   a  is pressed and sandwiched between the heated heat roller  41  and opposite roller  42 , together with the intermediate transfer film  21 , by the operation of the heat roller driver D 41  while being driven to move toward the conveyance unit ST 3  by the motor M 41 . The card material  31   a  is brought into pressure contact with the transfer image receiving layer  21   c  of the intermediate transfer film  21 . 
     Through the aforementioned movement of the card material  31   a  in pressure contact, a partial range of the intermediate image P, formed in the transfer image receiving layer  21   c  by the transfer device  51 , is transferred onto the card material  31   a  to form an image Pc. That is, the image Pc is formed by retransfer on the surface of the card material  31   a  as a formed image, thus producing the card  31 . The card  31  with the image PC retransferred and formed thereon is conveyed to the conveyance unit ST 3 , and is stacked and accommodated in an external stocker  36 , for example. 
     The timing at which retransfer is executed is not limited. Retransfer may be executed after the intermediate image P is formed in one of the frames F, before the intermediate image P is formed in the next frame F. Alternatively, retransfer may be executed after the intermediate image P is formed in plural frames F. 
     The storage unit MR previously stores an operation program for executing the entire operation of the printer PR including the transfer device  51 , the transfer image information J 3 , which is information of an image to be transferred, and the like. The contents stored in the storage unit MR are referred to by the controller CT when needed. The transfer image information J 3  is supplied to the controller CT through the communication unit  37  as the input unit from the external data device  38  (refer to  FIG. 2 ), and is stored in the storage unit MR. 
     Next, a description is given of the method of creating the glossy image data SN 2  by the glossy image data transmitter CT 2 . 
     In the color image data SN 1  externally supplied, the data structure of each pixel constituting an image is composed of 8 bits (256 gradations) for each color of red, green, and blue, as illustrated in  FIG. 7 . 
     The color image density acquisition unit CT 2   a  acquires the density of each pixel included in the color image data SN 1  as a density value N through calculation, for example. To be specific, the color image density acquisition unit CT 2   a  calculates the density value as the complement number of the luminance value. 
     To be more specific, the color image density acquisition unit CT 2   a  calculates a luminance value Lu by Equation (1). Herein, maxRGB and minRGB are maximum and minimum values among the R, G, and B values of each pixel, respectively.
 
 LU =[(maxRGB)+(minRGB)]/2  (1)
 
     Next, based on the calculated luminance LU, the density value N is calculated by Equation (2).
 
 N= 255 −LU   (2)
 
     The color image density acquisition unit CT 2   a  calculates the density value N of each pixel and stores in the storage unit MR the calculated density values of all the pixels in the predetermined region as density value information. The predetermined region is properly set in a color image represented by the color image data SN 1 . The predetermined region may be the entire region of the color image or may be any partial region thereof. 
     Based on the density value N of each pixel obtained by the color image density acquisition unit CT 2   a , the glossy image density decision unit CT 2   b  sets the density value of gloss obtained by transfer of the metal ink of the corresponding pixel as a gloss density value NM. 
     In the decision process, the gloss density value NM of a pixel, the density value N of which is less than a previously-configured particular density value Na, is a value smaller than the density value N. The gloss density value NM is set to the minimum possible value of the gloss density value NM, for example. This criterion on for the decision is referred to as a first decision criterion. Herein, the gloss density value NM is set to 0 according to the first decision criterion. 
     On the other hand, for a pixel, the density value N of which is equal to or greater than the particular density value Na, a second decision criterion is applied to calculate the gloss density value NM based on Equation (3).
 
 NM =( N−Na )×[255/(255 −Na )]  (3)
 
     According to the second decision criterion, the gloss density value NM is set larger than the minimum possible value of the gloss density value NM, according to the first decision criterion, for example. 
     The gloss density value NM, obtained by Equation (3), is a number with a decimal point, the gloss density value NM is rounded to a whole number. The gloss density value NM is a value in a range from 0 to 255 by Equation (3), and is represented as 8 bit data. The minimum possible value of the gloss density value NM is therefore 0. 
     The particular density value Na is configured so that when the transferred metal inks are scattered in a dot manner in a high-lightness region with a density value which is close to but less than the particular density value Na, the dots are recognized prominently, and the formed image is determined to have poor quality. The particular density value Na is previously set to a proper value by experiments or the like, and is stored in the storage unit MR, for example. 
     The glossy image density decision unit CT 2   b  calculates the gloss density value NM of each pixel in a predetermined region, and stores the gloss density values of all the pixels in the predetermined region as gloss density value information in the storage unit MR. To be specific, for pixels which are intended to be given gloss, the glossy image density decision unit CT 2   b  associates each of the pixels with the gloss density value NM, which specifies the density of the gloss. 
     Based on the gloss density value NM of each pixel decided by the glossy image density decision unit CT 2   b , the dithering processor CT 2   c  performs pseudo gradation processing by a dither method (dithering), for example, to create the glossy image data SN 2 . Using dithering, a desired gloss density can be represented by increasing or decreasing the number of pixels printed with the metal ink per area. 
     The dithering processor CT 2   c  performs pseudo gradation processing for the 8-bit gloss density value of each pixel into 1-bit data to create the glossy image data SN 2 . The dithering processor CT 2   c  stores the glossy image data SN 2  in the storage unit MR. 
     By the aforementioned method, the glossy image data SN 2  is created. 
     Next, a description is given of a specific operation example of the color image data transmitter CT 1 , and the glossy image data transmitter CT 2 . 
     It is assumed, for example, that the R, G, and B values of a certain pixel Qa in the color image data SN 1  are 48, 72, and 96, respectively (refer to  FIG. 8 ). 
     In this case, the color image data transmitter CT 1  creates the image data SN 1   y , SN 1   m , and SN 1   c  of the respective color inks so that the R, G, and B values for a transferred pixel which is transferred and superimposed on the intermediate transfer film  21  as a pixel corresponding to the pixel Qa, are 48, 72, and 96, respectively. The color image data transmitter CT 1  then transmits the created image data to the thermal head  16 . 
     The color image density acquisition unit CT 2   a  calculates the density value N of the pixel Qa through Equations (1) and (2) by using the R, G, and B values of the pixel Qa as shown in Equations (4) and (5).
 
 LU =(96+48)/2=72  (4)
 
 N= 255−72=183  (5)
 
     The glossy image density decision unit CT 2   b  determines whether the obtained density value N is less than the particular density value Na (Step  1  in  FIG. 9 ). Herein, the particular density value Na is set to 25 in advance. In this case, as N=183, the density value N is determined to be equal to or greater than the particular density value Na (No in Step  1 ). 
     The glossy image density decision unit CT 2   b  decides the gloss density value NM, which specifies the gloss given in association with the pixel Qa, based on Equations (3) as shown in Equation (6) (Step  2  in  FIG. 9 ).
 
 NM =(183−25)×[255/(255−25)]≈175  (6)
 
     As illustrated in  FIG. 10 , it is assumed that the R, G, and B values of a pixel Qb, which is different from the pixel Qa, are 250, 230, and 240, respectively. 
     In this case, each color ink is transferred and superimposed in accordance with the image data SN 1   y , SN 1   m , and SN 1   c , so that the R, G, and B values of a transferred pixel which is transferred and superimposed on the intermediate transfer film  21  as a pixel corresponding to the pixel Qb, are 250, 230, and 240, respectively. 
     The color image density acquisition unit CT 2   a  calculates the density value N of the pixel Qb through Equations (1) and (2) by using the R, G, and B values of the pixel Qb, as shown in Equations (7) and (8).
 
 LU =(250+230)/2=240  (7)
 
 N= 255−240=15  (8)
 
     The glossy image density decision unit CT 2   b  determines if the obtained density value N is less than the particular density value Na (Step  1  in  FIG. 9 ). In this case as N=15, the density value N is determined to be less than the particular density value Na (Yes in Step  1 ). 
     The glossy image density decision unit CT 2   b  sets the gloss density value NM, which specifies the gloss given in association with the pixel Qb less than the density value N (less than 15). In this example, the gloss density value NM is set to 0 (Step  3  in  FIG. 9 ). 
     The metal ink is transferred in the binary manner previously described. The gloss density value NM of each pixel is therefore subjected to pseudo gradation processing by the dithering processor CT 2   c  into 1-bit data, and is then outputted as the glossy image data SN 2 . 
     As for the data structure of each pixel in the color image data SN 1 A and glossy image data SN 2  outputted from the color and glossy image data transmitters CT 1  and CT 2 , the R, G, and B values are each composed of 8 bits, and the gloss density value NM (a S value in  FIG. 11 ) is composed of one bit. 
     The metal ink is transferred to the intermediate transfer film  21  in accordance with the glossy image data SN 2 , described in detail above. In this transfer process for the pixel Qa, the metal ink is transferred in a binary manner by the pseudo gradation processing such as dithering, so that the gloss density corresponding to the gloss density value NM=175 can be obtained. For the pixel Qa, the metal ink is not transferred, since the gloss density value NM is set to 0. 
     Next, with reference to  FIGS. 12 to 19 , a description is given of the specific operation and method to form an image on the intermediate transfer film  21  with the transfer device  51 , using the color image data SN 1 A and glossy image data SN 2 . 
     The transfer device  51  performs a rewinding operation and a cueing operation in the operation to transfer the color inks of three colors and the metal ink. 
     The operation procedure described below is a procedure to transfer the intermediate image P to a frame F 1  of the intermediate transfer film  21 . 
       FIGS. 12 and 13  illustrate the thermal head  16 , which is not movable in the conveyance direction (the longitudinal direction) of the ink ribbon  11 , the positions of the ink ribbon  11  and intermediate transfer film  21  relative to the position of the thermal head  16 , and the transferred contents. 
     In  FIGS. 12 and 13 , the surface of the ink layer  11   b  of the ink ribbon  11  and the surface of the transfer image receiving layer  21   c  of the intermediate transfer film  21 , which face each other and are in close contact during the transfer operation, are illustrated side by side. 
     In  FIGS. 12 and 13 , the ink layers  11   b  of the ink group  11   b   1  involved in transfer are given serial numbers starting with 1. For example, ink layers  11 Y 1  to  11 S 1  indicate ink layers  11 Y to  11 S of a first ink group  11   b   1 . 
     The frames F are given serial numbers starting with 1 in the order of frames, in which the intermediate image P is transferred and formed. For example, F 1  indicates a frame in which the intermediate image P is transferred and formed at first. Images of each ink to be transferred are indicated by serial numbers in brackets. For example, image M( 1 ) refers to the first transfer image transferred with magenta ink (an image of magenta to be formed in the frame F 1 ). Similarly, image C( 1 ) refers to the first transfer image transferred with cyan ink (an image of cyan to be formed in the frame F 1 ). 
     As illustrated in  FIG. 12 , the yellow ink layer  11 Y 1  is aligned with the frame E 1  by the cueing operation. 
     Next, the thermal head  16  is moved to the pressure contact position, and the ink ribbon  11  and intermediate transfer film  21  are brought into contact with each other and are moved downward together in  FIG. 12 . The ink of the yellow ink layer  11 Y 1  is therefore transferred to the frame F 1 , according to the image data SN 1   y  to form an image Y( 1 ). 
     The aforementioned close contact movement is performed by one frame. The feeding direction of the ink, ribbon  11  is the winding direction (the forward direction), and the feeding direction of the intermediate transfer film  21  is the rewinding direction (the backward direction). 
       FIG. 13  illustrates the state where the image Y( 1 ) is completely transferred to the intermediate transfer film  21 . In the frame F 1  of the intermediate transfer film  21 , the image Y( 1 ) of the yellow ink is transferred and formed. In the ink layer  11 Y 1  of the ink ribbon  11 , the ink in the range (indicated by hatched lines) corresponding to the image Y( 1 ) is thinner than the other range, or is removed completely. 
     Next, in the frame F 1 , the image Y( 1 ) is transferred with the ink of the yellow ink layer  11 Y 1 . As illustrated in  FIG. 13 , ink of the magenta ink layer  11 M 1  is to be transferred and superimposed, according to the image data SN 1   m  as an image M( 1 ). 
     Next, as illustrated in  FIG. 14 , the magenta ink layer  11 M 1  is aligned with the frame F 1  by the cueing operation. 
     In this cueing operation, the thermal head  16  is separated from the ink ribbon  11  at the separation position. The ink ribbon  11  is fed downward from the state of  FIG. 13  (forward feeding), while the intermediate transfer film  21  is rewound upward from the state of  FIG. 13  (forward feeding). 
     Next, the thermal head  16  is moved to the pressure contact position. The ink ribbon  11  and intermediate transfer film  21 , in close contact with each other, are move downward in  FIG. 14 . The ink of the magenta ink layer  11 M 1  is transferred to the frame F 1 , according to the image data SN 1   m  to form the image M( 1 ). 
     In the frame F 1 , an image composed of the image Y( 1 ) and image M( 1 ) superimposed on each other is formed as illustrated in  FIG. 15 . 
     In a similar manner, the ink of the cyan ink layer  11 C 1  is transferred and superimposed in the frame F 1 , according to the image data SN 1   c  as an image C( 1 ). In the frame F 1 , an image composed of the images Y( 1 ), M( 1 ), and C( 1 ) superimposed on each other is thereby formed. 
     In a similar manner, furthermore, the metal ink of the ink layer  11 S 1  is transferred and superimposed in the frame F 1 , to form an image S( 1 ) of the glossy image Ps (refer to  FIG. 21B ) according to the glossy image data SN 2  created by the glossy image data transmitter CT 2 . 
       FIG. 16  illustrates the state where the image S( 1 ) of the metal ink as the fourth color is completely transferred. In the frame F 1 , the images Y( 1 ), M( 1 ), C( 1 ), and S( 1 ) are transferred and superimposed, to form an image P( 1 ) as the intermediate image P. The schematic cross-sectional view of the intermediate transfer film  21  in this state is illustrated in  FIG. 17 . 
     The transfer image receiving layer  21   c  includes dye Y 1  (indicated by white ellipses) of the yellow ink sublimated and transferred, dye MI (indicated by hatched ellipses) of the magenta ink, dye CI (indicated by cross-hatched ellipses) of the cyan ink, and pigment SI of the metal ink (indicated by rectangles). 
     The pigment SI of the metal ink is transferred at the end, and is therefore received in the far side from the film base  21   a  in the transfer image receiving layer  21   c.    
     The image P( 1 ) is composed of the metal ink transferred based on the glossy image data SN 2 . As described above, in the region with the density less than the previously set particular density value Na, the metal ink is not transferred. In the region with the density equal to or greater than the particular density value Na, the metal ink is transferred so that the shades of gloss can be visually recognized by area modulation of the pseudo gradation processing. 
     In the frames subsequent to the frame F 1 , an image P( 2 ) and subsequent images can be formed in the same way as the image P( 1 ) is formed in the frame F 1 . A part of the intermediate image P formed in each frame F is retransferred to the corresponding one of the card materials  31   a  as the image Pc by the retransfer device  52 . 
       FIG. 18  illustrates the state of the intermediate transfer film  21  after the image P( 1 ) formed in the frame F 1  (illustrated in  FIG. 16 ) is retransferred to the card material  31   a . To be specific, a part of the image P( 1 ) is transferred to the card material  31   a  to form a retransfer range P( 1 ) c  (dotted part). 
       FIG. 19  is a partial cross-sectional view of the card  31  with the image retransferred thereon. The transfer image receiving layer  21   c  is transferred to the entire surface of the card material  31   a , which is the card  31  with no image transferred thereon. The surface of the transfer image receiving layer  21   c , opposite to the ribbon base  11   a , is located on the card material  31   a  side after the transfer process. The metal ink is therefore located on the card material  31   a  side. 
     When part of the intermediate transfer film  21  is transferred to the card material  31   a , where the metal ink is transferred and superimposed on the color ink transferred part, the color inks are laid on the metal ink on the card material  31   a.    
       FIG. 20  is a schematic view illustrating the card  31  (the cross sectional view thereof is illustrated in  FIG. 19 ) irradiated with light LG. 
     In  FIG. 20 , metal ink transferred sections Ac with the metal ink transferred thereto (approximately) regularly reflects the light LG with a high directivity, and outputs the same as reflection light LGa. Since the color inks transmit light, the reflected light LGa is recognized as glossy color reflecting the colors of the color inks laid on the metal ink. 
     When the light LG is incident on the surface of the card material  31   a , metal ink non-transferred sections Ad with no metal ink transferred thereon diffusely reflects, as indicated by diffuse reflection light LGb for the surface of the card material  31   a  that has a surface roughness typical as a resin plate. 
     When an observer&#39;s eye E is located in the outgoing direction of the reflected light LGa, the metal ink transferred sections Ac are visually recognized as metal glossy color regions, remarkably brighter than the metal ink non-transferred sections Ad. 
     On the other hand, the observer&#39;s eye E is not located in the outgoing direction of the reflected light LGa, and the eye E receives the diffusely reflected light LGb from the metal ink non-transferred sections Ad much more than the reflected light LGa from the metal ink transferred sections Ac. The metal ink transferred sections Ac are visually recognized as a dark region. 
     Next, a description is given of a case where the transfer image information J 3 , including the color image data SN 1  of a color image Pd with a density as illustrated in (a) of  FIG. 21 , is supplied to the controller CT. 
     As illustrated in (a) of  FIG. 21 , the color image Pd is a horizontally-long rectangle. The density value N of pixels located at the left end of the color image Pd is 0 as the minimum density, and the density value N of pixels located at the right end is 255 as the maximum density. In the color image Pd, the density value N of the pixels increase linearly, from the left end to the right end. 
     Dashed line Lh, illustrated in (a) of  FIG. 21 , indicates the positions of pixels the density value N of which is 25. The value of 25 of the density value N is stored as the particular density value Na in the storage unit MR. 
     If the transfer printing with the metal ink is performed through pseudo gradation processing so that the density value N in the area Aa on the left side of the dashed line Lh is the same as the density value N of the color image Pd, the transferred metal ink is scattered in the form of dots, and the formed image has poor quality. 
     In the printer PR, the color image data SN 1  of the color image Pd is processed based on Equations (1) to (3), described above by the color image density acquisition unit CT 2   a  and glossy image density decision unit CT 2   b . In other words, the gloss density value NM is decided based on the first and second decision criteria. 
     The color image data SN 1  of the color image Pd is further subjected to dithering by the dithering processor CT 2   c  into the glossy image data SN 2  of the glossy image Ps, having the shades of gloss as illustrated in (b) of  FIG. 21 . 
     In (b) of  FIG. 21 , the gloss density values NM are 0 in the region ASa on the left side of the dashed line Lh. In the region ASb on the right side of the dashed line Lh, the gloss density value NM of the pixels located at the left end is the lowest density of 0, and the gloss density value NM of the pixels located at the right end is the highest density of 255. In the region ASb, the gloss density value NM increases linearly from the left end to the right end. 
     As apparent from (a) and (b) of  FIG. 21 , transfer printing with the metal ink is not performed in the region ASa of the glossy image Ps, which corresponds to the region Aa of the color image Pd. In the region ASb of the glossy image Ps, which corresponds to the region Ab of the color image Pd, the metal ink is transferred and printed so that the gloss density value NM increases as the density value N of the color image Pd increases from the left end to the right end. 
     The printer PR forms a glossy color image so that the transferred metal ink is not dispersedly recognized in a low-density region. The formed glossy color image has high quality. 
     As described in detail according to the printer PR of Example 1, the metal ink transferred region is controlled so that little or no metal ink transferred part is produced in a high-lightness region in the formed image. 
     For example, the particular density value Na is configured based on a transfer image of color ink. The area of the image in which the density value is less than the particular density value Na is determined to be a high-lightness region. In the high lightness region, the metal ink is transferred so that the density characteristics of the metal are suppressed more than the density characteristics of the color inks. 
     It is therefore possible to transfer and form a glossy color image on the transfer body, such as a card with high quality. Moreover, it is possible to manufacture a card with a high-quality glossy color image formed on the surface thereof. 
     Example 2 
     In the printer PR as Example 1, the image data transmitter CTb is provided for the controller CT. However, the printer is not limited to the configuration of Example 1. The image data transmitter CTb may be included in an external computer  61 , which constitutes a printing system together with the printer. As Example 2, a printing system SY as an example of the printing system is described.  FIG. 22  illustrates a schematic configuration of the printing system SY. 
     The printing system SY includes a printer PRA and the computer  61 . The printer PRA differs from the printer PR of Example 1 in including a controller CIA not including the image data transmitter CTb instead of the controller CT. 
     The printer PRA includes the controller CTA, including a central processing unit CTa, the storage unit MR, the transfer device  51 , and the retransfer device  52 . 
     On the other hand, the computer  61  includes a central processing unit  63 , a storage unit  64 , and a printer driver  62  for driving the printer PRA. 
     The printer driver  62  includes a block corresponding to the image data transmitter CTb in the printer PR. The printer driver  62  includes the color image data transmitter CT 1 , and the glossy image data transmitter CT 2 . 
     The glossy image data transmitter CT 2  includes the color image density acquisition unit CT 2   a , glossy image density decision unit CT 2   b , and dithering processor CT 2   c . The glossy image data SN 2  is created by the glossy image data transmitter CT 2  of the printer driver  62 . 
     The color image data SN 1 A and glossy image data SN 2  are created by the color image data transmitter CT 1  and glossy image data transmitter CT 2 , respectively, and are sent to the printer PRA by wire or wirelessly. The printer PRA and computer  61  are connected via the Internet, for example. 
     The creation of the glossy image data SN 2  in the computer  61 , and the transfer operation and retransfer operation in the printer PRA do not need to be executed successively. 
     The methods of creating the color image data SN 1 A and glossy image data SN 2  are the same as those of Example 1. The transfer and retransfer operations in the printer PRA are the same as those of the printer PR of Example 1, and provide the same effects as those of Example 1. 
     The present invention is not limited to the configurations and procedures of Examples 1 and 2, and can be changed without departing from the scope of the present invention. 
     The way to decide the gloss density value NM in the glossy image density decision unit CT 2   b  is not limited to the way based on Equations (3) described above and the like. This is described with reference to  FIG. 23 . 
     (a) of  FIG. 23  is a graph representing the contents of decision by Equations (3) described above. The horizontal axis of (a) of  FIG. 23  represents the density value N of a color image. The density value N is 0 at the left end, and is 255 at the right end. The vertical axis represents the gloss density value NM decided by the glossy image density decision unit CT 2   b.    
     The thick line G 2  illustrates the relationship between the density value N and gloss density value NM. A dashed dotted line G 1  illustrates the case where the density value N increases linearly. 
     In (a) of  FIG. 23 , as illustrated by the thick line G 2 , the gloss density value NM is 0 when the density value N is from 0 to the particular density value Na. The gloss density value NM increases linearly with the density value N when the density value N is equal to or greater than the particular density value Na. 
     (b) to (e) of  FIG. 23  are modifications of (a) of  FIG. 23 . The thick lines G 3  to G 6  illustrate modifications of the relationship between the density value N and gloss density value NM. 
     In (b) of  FIG. 23  as illustrated by the thick line G 3 , the gloss density value NM increases linearly at a rate smaller than that of the dotted dashed line G 1  with the density value N when the density value N is from 0 to the particular density value Na. The gloss density value NM increases linearly at a rate larger than that of the dotted dashed line G 1  with the density value N when the density value N is equal to or greater than the particular density value Na. 
     In (c) of  FIG. 23 , as illustrated by the thick line G 4 , the gloss density value NM is 0 when the density value N is from 0 to the particular density value Na and increases in a curved manner with the density value N when the density value N is equal to or greater than the particular density value Na. 
     In (d) of  FIG. 23 , as illustrated by the thick line G 5 , the gloss density value NM is smaller than the dotted dashed line G 1 , and increases in a curved manner with the density value N when the density value N is from 0 to the particular density value Na. The gloss density value NM is partially equal to or greater than the dashed dotted line G 1 , and increases in a curved manner with the density value N when the density value N is equal to or greater than the particular density value Na. 
     In (e) of  FIG. 23  as illustrated by the thick line G 6 , the gloss density value NM is smaller than the dotted dashed line G 1 , and increases in a curved manner with the density value N when the density value N is from 0 to the particular density value Na. The gloss density value NM increases linearly in the same manner as the dotted dashed line G 1  with the density value N when the density value N is equal to or greater than the particular density value Na. 
     As described above, the way to decide the gloss density value NM in the glossy image density decision unit CT 2   b  is not limited to the way illustrated in (a) of  FIG. 23  and may be configured as illustrated in (b) to (e) of  FIG. 23 . 
     In the example illustrated in (a) of  FIG. 23  described in Example 1, and modifications described with reference to (b) to (e) of  FIG. 23 , the gloss density value NM, decided according to the second decision criterion, is larger than the minimum possible value of the gloss density value NM, according to the first decision criterion. To be more specific, the gloss density value NM, decided according to the second decision criterion, is set to a value larger than the maximum possible value of the gloss density value NM, according to the first decision criterion. 
     By setting the gloss density value NM decided according to the second decision criterion larger than the maximum possible value of the gloss density value NM according to the first decision criterion, the gloss density value NM decided according to the second decision criterion when the density value N of a pixel is equal to or greater than the particular density value Na is always larger than the gloss density NM decided according to the first decision criterion when the density value N is less than the particular density value Na. Accordingly, the gradation of gloss in the glossy image Ps is recognized more naturally. 
     In the above description, the ink ribbon includes the ink layers of four colors in total: three color (yellow, magenta, and cyan) inks, and metal ink. However, the ink ribbon may include ink layers of five colors in total: four color (yellow, magenta, cyan, and black) inks, and metal ink. The operation in the case of using the ink ribbon including the five color ink layers can be executed in the same manner as in the case of using the ink ribbon  11  of four colors, except for the execution of an additional operation of transferring and superimposing black ink. 
     The region (referred to as a gloss target region), for which the glossy image data SN 2  is created by the glossy image data transmitter CT 2 , needs to be at least a part of the image region corresponding to the color image data SN 1 . 
     The gloss target region may include plural regions in one color image. When there are plural gloss target regions, the particular density value Na used for each region may be different from each other. 
     The information that specifies the gloss target region and the particular density value and density change characteristics used when creating the glossy image data SN 2  corresponding to each gloss target region, can be previously configured by a user for each set of color image data SN 1 , and included in the transfer image information J 3 . 
     The printers PR and PRA are retransfer printers, but may be transfer devices which manufacture a product such as a card, including an image formed by transfer from the ink ribbon  11  without using the retransfer unit ST 1 . 
     To be specific, for example, the printer of the present invention may be a transfer device which cuts out the frames F of the intermediate transfer film  21  with an image transferred thereon into a predetermined shape such as film cards. The printer may be a transfer device which directly transfers an image to the transfer body such as a card instead of the intermediate transfer film  21 . 
     In such a transfer device that produces a product without performing retransfer, metal ink is transferred after the color inks are transferred in the same manner as the transfer operation in the printers PR and PRA when the transfer body transmits light to which each ink from the ink ribbon  11  is transferred and superimposed. 
     This allows a glossy image to be visually recognized when the transfer body is seen from the opposite side to the surface, on which the images are transferred. 
     When the transfer body does not transmit light to which each ink from the ink ribbon  11  is transferred and superimposed, the metal ink for a glossy image is transferred first, and the color ink of each color image is then transferred. 
     The formed image therefore has a structure in which the metal ink is laid on the side closest to the transfer body, and color inks are laid on the metal ink. This allows a glossy image to be visually recognized when the transfer body is seen from the side to which the images are transferred. 
     The particular density value Na is not limited to a value previously configured and stored in the storage unit MR. The particular density value Na may be configured corresponding to each of color images as raw images and may be included in the transfer image information J 3 . The particular density value Na can be configured arbitrarily, and is not limited to 25 described above.