Patent Publication Number: US-2022214639-A1

Title: Foil transfer device

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a continuation of International Application No. PCT/JP2020/035207 filed on Sep. 17, 2020, which claims priority from Japanese Patent Application No. 2019-175554 filed on Sep. 26, 2019, and Japanese Patent Application No. 2020-012595 filed Jan. 29, 2020, the disclosures of all which are incorporated herein by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     This disclosure relates to a foil transfer device for transferring foil onto a sheet. 
     BACKGROUND ART 
     A foil transfer device in which a foil film containing foil is laid on and heated with a sheet having a toner image formed thereon to transfer the foil onto the toner image is known in the art. 
     SUMMARY 
     In this foil transfer device, when a sheet and a foil film laid thereon are heated to high temperatures, the easy-to-release property of the foil film being about to be separated from a sheet would disadvantageously become degraded, so that the foil cannot be transferred as desired. 
     It would be desirable to improve the easy-to-release property of the foil film to be separated from a sheet. 
     In one aspect, a foil transfer device for transferring a foil-containing transfer layer from a foil film having the transfer layer, onto a sheet laid on the foil film is disclosed. The foil transfer device comprises a supply reel on which a foil film is wound and which is configured to supply the foil film, a take-up reel on which to take up the foil film, a heating member configured to heat the foil film, a pressure member configured to press the foil film and the sheet between the pressure member and the heating member, a separator configured to change a direction of travel of the foil film having passed through between the heating member and the pressure member, into a direction different from a direction of conveyance of the sheet, to thereby separate the foil film from the sheet, and a first fan configured to blow air toward the foil film positioned between the heating member and the separator. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, their advantages and further features will become more apparent by describing in detail illustrative, non-limiting embodiments thereof with reference to the accompanying drawings, in which: 
         FIG. 1A  is a diagram showing a foil transfer device according to a first embodiment; 
         FIG. 1B  is a section view showing a structure of a foil film; 
         FIG. 2  is a diagram showing an open cover state of the foil transfer device; 
         FIG. 3  is an exploded perspective view of a film unit as disassembled into a holder and a film cartridge; 
         FIGS. 4A to 4C  are perspective views of three kinds of film cartridges with foil films having different widths and positions; 
         FIG. 5  is a diagram showing positions of the temperature detectors relative to the foil films; 
         FIG. 6  is a perspective view showing the foil transfer device; 
         FIG. 7  is a section view showing a first duct; 
         FIG. 8  is a diagram showing a foil transfer device according to a second embodiment; 
         FIG. 9  is a diagram showing an open cover state of the foil transfer device; 
         FIG. 10  is a partially enlarged view showing a heat roller and its vicinity in  FIG. 8 ; 
         FIG. 11  is a diagram for showing relative positions of a second guide shaft and a thermistor; 
         FIG. 12  is a flowchart showing a control process to be executed by a controller upon power-up in the second embodiment; 
         FIG. 13  is a flowchart showing a foil transfer control; 
         FIG. 14  is a flowchart showing a control process, including a cooldown process, to be executed by the controller in the second embodiment; 
         FIG. 15  is a flowchart showing the cooldown process; 
         FIG. 16  is a flowchart showing a control process to be executed by a controller upon power-up in a third embodiment; 
         FIG. 17  is a flowchart showing a control process, including a cooldown process, to be executed by the controller in the third embodiment; 
         FIG. 18  is a flowchart showing a control process, including a cooldown process, to be executed by the controller in a fourth embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     A description will be given of several embodiments of a foil transfer device with reference made to the drawings where appropriate. 
     In the following description, directions will be referred to as directions shown in  FIG. 1A . That is, the right-hand side of  FIG. 1A  is referred to as “front”, the left-hand side of  FIG. 1A  as “rear”, the front side of the drawing sheet of  FIG. 1A  as “left”, and the back side of the drawing sheet of  FIG. 1A  as “right”. Similarly, upward/downward directions (upper/lower sides) of  FIG. 1A  are referred to as “upward/downward (upper/lower)”. 
     First, a detailed description will be given of a first embodiment with reference made mainly to  FIGS. 1 to 7 . As shown in  FIG. 1A , a foil transfer device  1  is a device for transferring a foil-containing transfer layer (a layer containing foil, such as of aluminum) onto a toner image formed on a sheet S by an image forming apparatus such as a laser printer. The foil transfer device  1  includes a housing  2 , a sheet tray  3 , a sheet conveyor unit  10 , a film supply unit  30 , and a transfer unit  50 . 
     The housing  2  is made of plastic or the like, and includes a housing main body  21  and a cover  22 . The housing main body  21  has an opening  21 A at its upper side (see  FIG. 2 ). The opening  21 A is an opening through which to allow a film unit FU as will be described later to be installed into or removed from the housing main body  21 . The opening  21 A faces upward. The cover  22  is a member for opening and closing the opening  21 A. A rear end portion of the cover  22  is rotatably supported by the housing main body  21 . 
     The sheet tray  3  is a tray on which sheets S such as paper, OHP film, etc., are to be placed. The sheet tray  3  is provided at a rear portion of the housing  2 . The sheets S of which surfaces having toner images formed thereon face downward are placed on the sheet tray  3 . 
     The sheet conveyor unit  10  includes a sheet feed mechanism  11  and a sheet ejection mechanism  12 . The sheet feed mechanism  11  is a mechanism that conveys sheets S on the sheet tray  3  one by one toward the transfer unit  50 . The sheet feed mechanism  11  includes a pickup roller  11 A and a retard roller  11 B. The pickup roller  11 A feeds a sheet S on the sheet tray  3  toward the transfer unit  50 . The retard roller  11 B is opposed to the pickup roller  11 A. The retard roller  11 B rotates in a direction opposite to a direction of feed of the sheets S to separate one sheet S from others. 
     The sheet ejection mechanism  12  is a mechanism that ejects a sheet S which has passed through the transfer unit  50 , to the outside of the housing  2 . The sheet ejection mechanism  12  includes a plurality of rollers. 
     The film supply unit  30  is a unit that supplies and lays a foil film F onto an underside of a sheet S conveyed from the sheet feed mechanism  11 . The film supply unit  30  includes a film unit FU, and a motor  95 , as an example of a driving source. 
     The film unit FU is configured, as shown in  FIG. 2 , to be removably installable from above into the housing main body  21 . The film unit FU includes a supply reel  31 , a take-up reel  35 , a first guide shaft  41 , a second guide shaft  42  as a separator, and a third guide shaft  43 . A foil film F is wound on the supply reel  31  of the film unit FU. 
     As shown in  FIG. 1B , the foil film F is a multilayer film made up of a plurality of layers. To be more specific, the foil film F includes a supporting layer F 1  and a supported layer F 2 . The supporting layer F 1  is a transparent substrate in the form of a tape and made of polymeric material, and supports the supported layer F 2 . 
     The supported layer F 2  includes a release layer F 21 , a transfer layer F 22 , and an adhesive layer F 23 . The release layer F 21  is a layer for facilitating separation of the transfer layer F 22  from the supporting layer F 1 , and is interposed between the supporting layer F 1  and the transfer layer F 22 . The release layer F 21  contains a transparent material, such as a wax-type resin, easily releasable from the supporting layer F 1 . 
     The transfer layer F 22  is a layer to be transferred onto a toner image, and contains foil. Foil is a thin sheet of metal such as gold, silver, copper, aluminum, etc. The transfer layer F 22  contains a colorant of gold-colored, silver-colored, red-colored, or other colored material, and a thermoplastic resin. The transfer layer F 22  is interposed between the release layer F 21  and the adhesive layer F 23 . 
     The adhesive layer F 23  is a layer for facilitating adhesion of the transfer layer F 22  to a toner image. The adhesive layer F 23  contains a material, such as vinyl chloride resin, acrylic resin, etc., which tends to adhere to a toner image heated by the transfer unit  50  which will be described later. 
     The supply reel  31  is made of plastic or the like, and includes a supply shaft  31 A on which a foil film F is wound, as shown in  FIG. 1A . One end of the foil film F is fixed to the supply shaft  31 A. The foil film F is wound on the supply shaft  31 A in such a manner that the supported layer F 2  containing the transfer layer F 22  is in contact with the supply shaft  31 A. In other words, when the foil film F is wound on the supply shaft  31 A, the supporting layer F 1  faces outside and the supported layer F 2  (transfer layer F 22 ) faces inside. Accordingly, in an outermost portion of a roll of the foil film F wound on the supply shaft  31 A, the supporting layer F 1  is positioned outside of the supported layer F 2 . 
     The take-up reel  35  is made of plastic or the like, and includes a take-up shaft  35 A on which to take up the foil film F. The other end of the foil film F is fixed to the take-up shaft  35 A. The foil film F is to be wound on the take-up shaft  35 A in such a manner that the supported layer F 2  containing the transfer layer F 22  comes in contact with the take-up shaft  35 A. In other words, when the foil film F is wound on the take-up shaft  35 A, the supporting layer F 1  faces outside and the supported layer F 2  (transfer layer F 22 ) faces inside. Accordingly, in an outermost portion of a roll of the foil film F wound on the take-up shaft  35 A, the supporting layer F 1  is positioned outside of the supported layer F 2 . 
     It is to be understood that in  FIG. 1A  or other drawing figures, the supply reel  31  and the take-up reel  35  are illustrated for convenience&#39;s sake as if the both reels were wound up to the maximum. In actuality, the film unit FU in new condition has its foil film F wound on the supply reel  31  in a roll of a maximum diameter, while no foil film F is wound on the take-up reel  35 , or the foil film F is wound on the take-up reel  35  but in a roll of a minimum diameter. When the film unit FU is at the end of its life (i.e., the foil film F has been exhausted), the foil film F is wound on the take-up reel  35  in a roll of a maximum diameter, while no foil film F is wound on the supply reel  31 , or the foil film F is wound on the supply reel  31  but in a roll of a minimum diameter. 
     The first guide shaft  41 , second guide shaft  42  and third guide shaft  43  are shafts for changing traveling directions of the foil film F. The first guide shaft  41 , second guide shaft  42  and third guide shaft  43  are made of SUS (stainless steel) or the like. The first guide shaft  41 , second guide shaft  42  and third guide shaft  43  may be made of SUS shafts covered with plastic covers. 
     The first guide shaft  41  is located upstream of the transfer unit  50  in a direction of conveyance of a sheet S. The first guide shaft  41  changes a traveling direction of the foil film F drawn out from the supply reel  31  into a direction approximately parallel to the direction of conveyance of the sheet S. The first guide shaft  41  is in contact with the supporting layer F 1  of the foil film F. The first guide shaft  41  guides the foil film F drawn out from the supply reel  31  to cause the foil film F to be placed under a sheet S being conveyed with a toner image facing downward so that the sheet S is laid on the foil film F. 
     When the foil film F guided by this first guide shaft  41  is conveyed toward the transfer unit  50 , the supported layer F 2  thereof (see  FIG. 1B ) faces upward. When a sheet S is fed to the transfer unit  50 , the sheet S is laid on the foil film F with the supported layer F 2  facing upward, and the sheet S and the foil film F are conveyed toward the transfer unit  50 . 
     The second guide shaft  42  is located downstream of the transfer unit  50  in the direction of conveyance of the sheet S. The second guide shaft  42  changes a traveling direction of the foil film F having passed through the transfer unit  50  (i.e., through between a pressure roller  51  and a heating roller  61 , which will be described later in detail) into a direction different from the direction of conveyance of the sheet S to thereby separate the foil film F from the sheet S. The second guide shaft  42  is in contact with the supporting layer F 1  of the foil film F. 
     The third guide shaft  43  is located between the second guide shaft  42  and the take-up reel  35 . The third guide shaft  43  guides the foil film F separated from the sheet S, to the take-up reel  35 . The third guide shaft  43  defines an angle at which the foil film F is separated from the sheet S (hereinafter referred to as “peel angle”). Herein, the peel angle is an angle formed by a portion of the foil film F stretched between the second guide shaft  42  and the third guide shaft  43  with respect to a portion of the foil film F stretched between the first guide shaft  41  and the second guide shaft  42 . In other words, the peel angle is an angle formed by the traveling direction of the foil film F after separated from the sheet S with respect to the traveling direction of the foil film F passing through the transfer unit  50 . The third guide shaft  43  changes a traveling direction of the foil film F guided by the second guide shaft  42  and guides the foil film F to the take-up reel  35 . The third guide shaft  43  is in contact with the supported layer F 2  (adhesive layer F 23 ) of the foil film F. 
     In the film unit FU installed in the foil transfer device  1 , the take-up reel  35  is caused to rotate in a counterclockwise direction as in  FIG. 1  by the motor  95  provided in the housing  2 . When the take-up reel  35  rotates, the foil film F wound on the supply reel  31  is drawn out, guided by the guide shafts  41 ,  42  and  43 , and taken up on the take-up reel  35 . To be more specific, during the foil transfer process, the foil film F is forwarded by the pressure roller  51  and the heating roller  61 , which will be described later, whereby the foil film F is drawn out from the supply reel  31 . The foil film F thus forwarded through between the pressure roller  51  and the heating roller  61  are taken up on the take-up reel  35 . 
     The transfer unit  50  is a unit that heats and pressurizes the sheet S and the foil film F laid on each other, to transfer the transfer layer F 22  onto a toner image formed on a sheet S. The transfer unit  50  includes a pressure roller  51  as an example of a pressure member, and a heating roller  61  as an example of a heating member. The transfer unit  50  applies heat and pressure to portions of a sheet S and a foil film F laid on each other and nipped between the pressure roller  51  and the heating roller  61 . 
     The pressure roller  51  is a roller comprising a cylindrical metal core with its cylindrical surface coated with a rubber layer made of silicone rubber. The pressure roller  51  is located above the foil film F, and is contactable with a reverse side (opposite to a side on which a toner image is formed) of the sheet S. 
     The pressure roller  51  has two end portions supported rotatably by the cover  22 . The pressure roller  51 , which in combination with the heating roller  61 , nips the sheet S and the foil film F, is driven to rotate by the motor  95  and causes the heating roller  61  to rotate accordingly. 
     The heating roller  61  is a roller comprising a cylindrical metal tube with a heater  62  located inside, to heat the foil film F and the sheet S. The heating roller  61  is located under the foil film F, and is in contact with the foil film F. The heating roller  61  extends across the width of the foil film F, in a direction (across-the-width direction) perpendicular to the traveling direction of the foil film F. The heater  62  generates heat to heat the heating roller  61 . 
     The foil transfer device  1  includes a contact/separation mechanism  70  configured to cause either one or both of the heating roller  61  and the pressure roller  51  to move between a contact position in which the pressure roller  51  is pressed against the heating roller  61  and a separate position in which the heating roller  61  and the pressure roller  51  are located apart from each other. In the present embodiment, the contact/separation mechanism  70  is configured to cause the heating roller  61  to move between a contact position in which the heating roller  61  is in contact with the foil film F and a separate position in which the heating roller  61  is separate from the foil film F. The contact/separation mechanism  70  is located between the supply reel  31  and the take-up reel  35  along a path of conveyance of a sheet S. The contact/separation mechanism  70  is configured such that when the cover  22  is in a closed state, the heating roller  61  is moved to the contact position and brought into contact with the foil film F at each time when a sheet S is supplied to the transfer unit  50 . Furthermore, the contact/separation mechanism  70  is configured such that when the cover  22  is open or when the process of transferring foil onto a sheet S is not executed in the transfer unit  50 , the heating roller  61  is kept in the separate position separate from the foil film F. 
     In the foil transfer device  1  configured as described above, sheets S stacked on the sheet tray  3 , with their front surfaces facing downward, are conveyed one by one toward the transfer unit  50  by the sheet feed mechanism  11 . Each sheet S thus conveyed to a position upstream of the transfer unit  50  in a sheet conveyance direction is laid on the foil film F supplied from the supply reel  31 , and further conveyed to the transfer unit  50  with a toner image of the sheet S being kept in contact with the foil film F. 
     In the transfer unit  50 , the sheet S and the foil film F nipped and passing through between the pressure roller  51  and the heating roller  61  are heated and pressurized by the heating roller  61  and the pressure roller  51 , so that foil (supported layer F 2 ) is transferred onto the toner image. 
     After the foil has been transferred, the sheet S and the foil film F adhered to each other are conveyed to the second guide shaft  42 . When the sheet S and the foil film F travels past the second guide shaft  42 , the traveling direction of the foil film F is changed into a direction different from the direction of conveyance of the sheet S; thereby, the foil film F is peeled from the sheet S, that is, the supported layer F 2  adhered to the toner image is separated from the supporting layer F 1  of the foil film F. 
     The foil film F peeled from the sheet S and containing the supporting layer F 1  separated from the supported layer F 2  adhered to the toner image on the sheet S is taken up on the take-up reel  35 . On the other hand, the sheet S on which the transfer layer F 22  (foil) of the foil film F is transferred and which is separated from the supported layer F 2  has a foil transferred surface facing downward and is ejected by the sheet ejection mechanism  12  to the outside of the housing  2 . 
     As shown in  FIG. 3  and  FIG. 4 , the film unit FU includes a holder  100  made of plastic or the like, and a film cartridge FC installable in and removable from the holder  100 . The film cartridge FC includes a supply reel  31  and a take-up reel  35  as described above, and a supply case  32 . The film cartridge FC installed in the holder  100  can be installed into and removed from the housing main body  21  through the opening  21 A of the housing main body  21 . 
     The supply reel  31  (more specifically, the supply case  32 ) and the take-up reel  35  are installable into and removable from the holder  100  in directions perpendicular to the axial direction of the supply reel  31 . 
     The supply case  32  is a hollow case accommodating the supply reel  31 . The supply case  32  is made of plastic or the like, and includes an outer peripheral wall  32 A having an approximately cylindrical shape, and two side walls  32 B each having an approximately discoidal shape. The side walls  32 B are provided at both ends of the outer peripheral wall  32 A. The supply reel  31  is rotatably supported by the side walls  32 B of the supply case  32 . 
     The outer peripheral wall  32 A has formed therein three recesses  32 D arranged in the axial direction of the supply reel  31 ; engageable pieces P 1 , P 2  and P 3  as identifiers can be fixed in the recesses  32 D, respectively. 
     Each of the side walls  32 B includes an engageable portion  32 C having an elongate shape as viewed from outside in the axial direction of the supply reel  31 . Each engageable portion  32 C is a portion to be guided by installation/removal guides G of the holder  100 , which will be described below. The engageable portion  32 C has a rounded-corner rectangular shape (more precisely, an elongated shape having two straight parallel sides and two round ends) as viewed from outside in the axial direction of the supply reel  31 . 
     The holder  100  includes a base frame  110  and a restraining frame  120  rotatably (movably) supported by the base frame  110 . 
     The base frame  110  supports the first guide shaft  41  and the second guide shaft  42  in such a manner as to render the first guide shaft  41  and the second guide shaft  42  rotatable. The base frame  110  includes a first holding portion  111 , a second holding portion  112 , two connecting portions  113  and two handles  114 . 
     The restraining frame  120  supports the third guide shaft  43  in such a manner as to render the third guide shaft  43  rotatable. 
     The first holding portion  111  is a portion that holds the supply case  32 . The first holding portion  111  holds the supply reel  31  via the supply case  32 . 
     The first holding portion  111  includes two side walls  111 B. 
     Each of the side walls  111 B has an installation/removal guide G for guiding the supply case  32  in predetermined directions when the supply case  32  is installed and removed. 
     At outer sides of the side walls  111 B, bosses  111 C are provided. Each boss  111 C is a portion to be guided by a first guide GD 1  formed in the housing main body  21  (see  FIG. 2 ), when the film unit FU is installed into and removed from the housing main body  21 . 
     The second holding portion  112  is a portion that holds the take-up reel  35 . To be more specific, the second holding portion  112  is combined with the restraining frame  120  to make up a hollow case, and the take-up reel  35  is accommodated in the hollow case. The take-up shaft  35 A of the take-up reel  35  protrudes outward in the axial direction of the take-up reel  35  from the second holding portion  112  and the restraining frame  120 ; protruded portions of take-up shaft  35 A each serve as a portion to be guided by a second guide GD 2  formed in the housing main body  21  (see  FIG. 2 ), when the film unit FU is installed into and removed from the housing main body  21 . 
     The two connecting portions  113  are portions that connect the first holding portion  111  and the second holding portion  112 . The connecting portions  113  are arranged apart from each other in the axial direction of the supply reel  31 . 
     With the connecting portions  113  being formed in this way, the holder  100  is provided with a through hole  100 A extending in a perpendicular direction perpendicular to the axial direction of the supply reel  31 . With this configuration, the heating roller  61  caused to move by the contact/separation mechanism  70  described above is allowed to pass through the through hole  100 A, so that the heating roller  61  can be brought into contact with, and separated from, the foil film F. 
     The handle  114  is provided on each of the connecting portions  113 . The handles  114  are located at opposite ends of the holder  100  corresponding to the ends of the take-up reel  35  apart from each other in the axial direction of the take-up reel  35 . 
     Different kinds of film cartridges FC with foil films having different widths and positions can selectively be installed in the holder  100  for use in the foil transfer device  1 . For example, a first film cartridge FC 1 , a second film cartridge FC 2 , or a third film cartridge FC 3  as shown in  FIGS. 4A, 4B and 4C  can be installed in the holder  100 . 
     A film unit FU in which the first film cartridge FC 1  with a first foil film F 10  having a width H 1  and located in a position shifted to one side in an across-the-width direction of the first foil film F 10  as shown in  FIG. 4A  is installed is herein referred to as a first film unit FU 1 . The first film unit FU 1  holds the first foil film F 10  in such a manner that when the first film unit FU 1  is installed in the foil transfer device  1 , the first foil film F 10  is located in a position shifted from the center of the heating roller  61  to a position closer to one end than to the other end of the heating roller  61 . The width H 1  is a width smaller than a width of a sheet S having a maximum width, of sheets S usable in the foil transfer device  1 , for example, 110 mm (half a width H 3  which will be described below). 
     In the first film unit FU 1 , the engageable pieces P 1 , P 2  are fixed in two of the three recesses  32 D formed in the outer peripheral wall  32 A, i.e., the center recess  32 D and either one of the left or right recess  32 D, while no engageable piece is fixed in the other of the left or right recess  32 D. 
     A film unit FU in which the second film cartridge FC 2  with a second foil film F 20  having a width H 2  and located in a position shifted to the center in the across-the-width direction of the second foil film F 20  as shown in  FIG. 4B  is installed is herein referred to as a second film unit FU 2 . The second film unit FU 2  holds the second foil film F 20  in such a manner that when the second film unit FU 2  is installed in the foil transfer device  1 , the second foil film F 20  is located in a central position in an axial direction of the heating roller  61 . The width H 2  is a width smaller than the width of a sheet S having the maximum width, of sheets S usable in the foil transfer device  1 , for example, 110 mm (half the width H 3  which will be described below). 
     In the second film unit FU 2 , the engageable pieces P 1 , P 3  are fixed in two of the three recesses  32 D formed in the outer peripheral wall  32 A, i.e., the left and right recesses  32 D, while no engageable piece is fixed in the center recess  32 D. 
     A film unit FU in which the third film cartridge FC 3  with a third foil film F 30  having a width H 3  as shown in  FIG. 4C  is installed is herein referred to as a third film unit FU 3 . The third film unit FU 3  holds the third foil film F 30  in such a manner that when the third film unit FU 3  is installed in the foil transfer device  1 , the third foil film F 20  is so located as to cover the heating roller  61  from one end to the other of the heating roller  61 . The width H 3  is a width greater than the width of a sheet S having the maximum width, of sheets S usable in the foil transfer device  1 , for example, 220 mm. 
     In the third film unit FU 3 , the engageable pieces P 1 , P 2  and P 3  are fixed in all the three recesses  32 D formed in the outer peripheral wall  32 A. 
     The housing main body  21  is configured to allow each of the film units FU 1 , FU 2  and FU 3  to be selectively installed therein. The foil transfer device  1  includes three sensors corresponding to the engageable pieces P 1 , P 2  and P 3  so that the kind of the film unit FU installed can be identified by a combination of signals outputted from the three sensors. 
     As shown in  FIG. 1A  and  FIG. 5 , the foil transfer device  1  includes a first temperature detector SE 1  and a second temperature detector SE 2  both of which are capable of detecting temperatures of the heating roller  61 . 
     The first temperature detector SE 1  is a thermostat configured to stop the supply of electricity to the heating roller  61  if the temperature of the heating roller  61  reaches or exceeds a predetermined value. The first temperature detector SE 1  is located downstream of the heating roller  61  and the pressure roller  51  in the direction of conveyance of a sheet S. The first temperature detector SE 1  is located in a position behind the foil film F such that the foil film F overlaps the first temperature detector SE 1  when an upper side of the foil film F positioned between the heating roller  61  and the second guide shaft  42  on which a sheet S is to be laid is viewed straight on in a direction perpendicular thereto (see  FIG. 1A ). 
     In other words, the first temperature detector SE 1  is located in a position under part of the foil film F positioned between the heating roller  61  and the second guide shaft  42  such that a projection of the first temperature detector SE 1  in a normal direction (i.e., a direction pointed, perpendicular to a surface of that part of the foil film F, toward that part of the foil film F) falls within that part of the foil film F. 
     The position of the first foil film F 10  of the first film cartridge FC 1  installed in the housing main body  21  in an across-the-width direction of the first foil film F 10  is different from the position of the second foil film F 20  of the second film cartridge FC 2  installed in the housing main body  21  in an across-the-width direction of the second foil film F 20 . To be more specific, the first foil film F 10  consists of a first half F 11  and a second half F 12 . The first half F 11  is a portion located on one side in the across-the-width direction of the first foil film F 10  with respect to a center CL (predetermined position) in the across-the-width direction of the first foil film F 10 . The second half F 12  is a portion located on the other side in the across-the-width direction of the first foil film F 10 . The first half F 11  of the first foil film F 10  is a portion located outside a region (indicated in chain double-dashed lines in  FIG. 5 ) to be occupied by the second foil film F 20  when the second film cartridge FC 2  is installed in the housing main body  21 , in the across-the-width direction. The second half F 12  of the first foil film F 10  is a portion (indicated by hatch lines in  FIG. 5 ) located within the region to be occupied by the second foil film F 20  when the second film cartridge FC 2  is installed in the housing main body  21 , in the across-the-width direction. 
     The first temperature detector SE 1  is located in such a position that the second half F 12  of the first foil film F 10  overlaps the first temperature detector SE 1  when the first film cartridge FC 1  is installed in the housing main body  21  and an upper side of the first foil film F 10  positioned between the heating roller  61  and the second guide shaft  42  is viewed straight on in the normal direction (i.e., a direction perpendicular to the upper surface). Accordingly, the position in which the first temperature detector SE 1  is located is such that the first foil film F 10  overlaps the first temperature detector SE 1  when the first film cartridge FC 1  is installed in the housing main body  21  and the upper side of the first foil film F 10  positioned between the heating roller  61  and the second guide shaft  42  is viewed straight on in the direction perpendicular thereto, and that the second foil film F 20  overlaps the first temperature detector SE 1  when the second film cartridge FC 2  is installed in the housing main body  21  and an upper side of the second foil film F 20  positioned between the heating roller  61  and the second guide shaft  42  is viewed straight on in a direction perpendicular thereto. It is to be understood, although not illustrated in the drawings, that the above-described position in which the first temperature detector SE 1  is located is further characterized in that the third foil film F 30  overlaps the first temperature detector SE 1  when the third film cartridge FC 3  is installed in the housing main body  21  and an upper side of the third foil film F 30  positioned between the heating roller  61  and the second guide shaft  42  is viewed straight on in a direction perpendicular thereto. 
     The second temperature detector SE 2  includes a first thermistor SE 21 , a second thermistor SE 22 , and a third thermistor SE 23 , which are capable of detecting a temperature for use in regulating an electric current to be passed through the heating roller  61 . The first thermistor SE 21 , the second thermistor SE 22 , and the third thermistor SE 23  are located upstream of the heating roller  61  and the pressure roller  51  in the direction of conveyance of a sheet S. 
     The first thermistor SE 21  is located in a first position in the across-the-width direction of the foil film F. The second thermistor SE 22  is located in a second position in the across-the-width direction of the foil film F. The second position is different from the first position in the across-the-width direction of the foil film F. The third thermistor SE 23  is located in a third position in the across-the-width direction of the foil film F. The third position is different from the first position and from the second position in the across-the-width direction of the foil film F. 
     To be more specific, the first thermistor SE 21  is located on a first side (that is one side with respect to a center of the heating roller  61  in the axial direction, i.e., at a position closer to one end than to the other end of the heating roller  61  in the axial direction) of the heating roller  61 . The second thermistor SE 22  is located at a position corresponding to the center of the heating roller  61  in the axial direction. The third thermistor SE 23  is located on a second side (that is the other side with respect to the center of the heating roller  61  in the axial direction, i.e., at a position closer to the other end than to the one end of the heating roller  61  in the axial direction). 
     As shown in  FIG. 1A , the foil transfer device  1  further includes a first fan  91 , a first duct D 1 , a power supply board EB, a second fan  92 , and a second duct D 2 . To be more specific, the cover  22  includes the first fan  91  and the first duct D 1 . The housing main body  21  includes the power supply board EB, the second fan  92 , and the second duct D 2 . 
     The first fan  91  is a sirocco fan. The first fan  91  is a fan configured to blow air toward the foil film F positioned between the heating roller  61  and the second guide shaft  42 . The first fan  91  is located upstream of the heating roller  61  in the direction of conveyance of a sheet S. 
     The first fan  91  is located above the foil film F. The first fan  91  is located within the first duct D 1 . 
     The first duct D 1  is located above the foil film F. The first duct D 1  is a duct through which to guide air forced out from the first fan  91 , toward a surface (a surface facing upward; an upper side on which a sheet S is to be laid) of the foil film F positioned between the heating roller  61  and the second guide shaft  42 . Accordingly, the first fan  91  is configured to be capable of blowing air toward a surface of the foil film F for a sheet S to be laid thereon. The first duct D 1  extends from the first fan  91  downstream in the direction of conveyance of a sheet S. The first duct D 1  is located above the pressure roller  51 . 
     The first duct D 1  has an air outlet D 11  at a downstream end portion thereof located downstream in the direction of conveyance of a sheet S. The air outlet D 11  is located in such a position, on an upper side of the path of conveyance of a sheet S, as to correspond to a position between the heating roller  61  and the second guide shaft  42  arranged along the path (on an underside of the path) of conveyance of a sheet S. The air outlet D 11  faces the upper side of the foil film F positioned between the heating roller  61  and the second guide shaft  42 . 
     As shown in  FIG. 6 , the cover  22  has an air intake  22 B at a side surface  22 A thereof. The air intake  22 B is made up of a plurality of slits, for example. The first fan  91  forces air taken in through the air intake  22 B, to flow through the first duct D 1  (see  FIG. 1A ) and blow from the cover  22  to the housing main body  21 . 
     As shown in  FIG. 7 , the first duct D 1  has an air intake D 12  that opens on the air intake  22 B of the cover  22 . The air intake D 12  is located between the side surface  22 A of the cover  22  and the first fan  91 . The aforementioned air outlet D 11  formed in the first duct D 1  extends across the width of the foil film F, specifically, across the width of the third foil film F 30  (i.e., from one side to the other throughout its width). In other words, the air outlet D 11  is formed from one side to the other across the width of the widest foil film F (third foil film F 30 ) of the group consisting of foil films F usable in the foil transfer device  1 . Cross-sectional area of the duct D 1  increases gradually with distance from the air intake D 12  toward the air outlet D 11 . 
     The power supply board EB is a substrate on which electronic components for supplying electric power to a heater  62  in the heating roller  61 , the motor  95 , etc. are mounted. As shown in  FIG. 1A , the power supply board EB is located in a lower and rearward position relative to the supply reel  31 . 
     The second fan  92  is an axial fan. The second fan  92  is a fan configured to force out air around the foil film F positioned between the heating roller  61  and the second guide shaft  42 . In other words, the second fan  92  is configured to force out air that has been caused to blow by the first fan  91  toward the foil film F positioned between the heating roller  61  and the second guide shaft  42 . 
     The second fan  92  is located below the supply reel  31  and the contact/separation mechanism  70 . The second fan  92  is located in such a position, on the underside of the path of conveyance of a sheet S (farther than the contact/separation mechanism  70  from the path of conveyance of a sheet S), as to correspond to a position between the supply shaft  31 A of the supply reel  31  and the take-up shaft  35 A of the take-up reel  35  arranged along the path (on the same underside of the path) of conveyance of a sheet S. 
     The second fan  92  as the axial fan has an axis  92 A of rotation, along which the direction of air flow is confined. The axis  92 A of the second fan  92  is directed toward a position between the supply reel  31  and the take-up reel  35 . The second fan  92  is located within the second duct D 2 . It is to be understood that the axis  92 A may preferably be directed toward a position between the heating roller  61  and the second guide shaft  42 . 
     The second duct D 2  is a duct through which to guide air around the power supply board EB to the second fan  92 . The second duct D 2  includes a first air intake hole D 21 , a plurality of second air intake holes D 22 , and a plurality of air outlet holes D 23 . 
     The first air intake hole D 21  is located between the power supply board EB and the second fan  92 . The first air intake hole D 21  opens toward the power supply board EB. 
     Each of the second air intake holes D 22  is located between the contact/separation mechanism  70  and the second fan  92  along the axial direction of the second fan  92 . Each of the second air intake holes D 22  opens on a region between the supply reel  31  and the take-up reel  35 . 
     Each of the third air outlet holes D 23  is located between the second fan  92  and an undersurface (bottom wall) of the housing main body  21  Each of the third air outlet holes D 23  opens on the bottom wall of the housing main body  21 . The undersurface of the housing main body  21  has a plurality of holes or openings. Accordingly, air forced out through the third air outlet holes D 23  is discharged below to the outside of the housing main body  21 . 
     As illustrated in  FIG. 1A , when the foil transfer device  1  is operated to execute a foil transfer process, the first fan  91  and the second fan  92  are activated. The first fan  91  causes air outside the housing  2  to be taken through the air intake  22 B of the cover  22  into the first duct D 1 , and to blow through the air outlet D 11  of the first duct D 1  toward the foil film F positioned between the heating roller  61  and the second guide shaft  42 . 
     Accordingly, when the foil film F is separated from a sheet S at the second guide shaft  42 , the foil film F and the sheet S (with the transfer layer F 22  transferred on the sheet S) are cooled with air taken in from outside, whereby the easy-to-release property can be improved. An air current that has been blown on the foil film F and the sheet S from above passes through clearances at the side edges of the foil film F and the sheet S, and flows further downward. 
     In this way, the air current produced by the first fan  91  flows downward through clearances at the sides of the first temperature detector SE 1  located under the foil film F positioned between the heating roller  61  and the second guide shaft  42 . Therefore, the first temperature detector SE 1  can detect the temperature of the heating roller  61  precisely without being adversely affected by the air current. 
     It is to be understood that the air current blowing against the sheet S or the foil film F positioned between the heating roller  61  and the second guide shaft  42  would possibly tend to move toward the second temperature detector SE 2 , but should get blocked by the heating roller  61  and the pressure roller  51 . Therefore, the second temperature detector SE 2  can be prevented from suffering from the effects of the air current. 
     The air (current) which has cooled the foil film F and the sheet S is caused to pass through clearances between the supply reel  31  and the take-up reel  35  (to be more specific, the clearance between the contact/separation mechanism  70  and the take-up reel  35 , and/or the clearance between the contact/separation mechanism  70  and the housing main body  21 , and the like), and drawn into the second duct D 2 , by the suction of the second fan  92 . On the other hand, air around the power supply board EB is also drawn into the second duct D 2 . Air drawn into the second duct D 2  is let out through the air outlet holes D 23  of the second duct D 2 , the holes in the undersurface of the housing main body  21 , and the like, to the outside of the housing  2 . 
     In the embodiment as described above, the following advantageous effects can be achieved. Since the foil film F and the sheet S positioned between the heating roller  61  and the second guide shaft  42  are cooled by air produced by the first fan  91 , the easy-to-release property of the foil film F from the sheet S can be improved. 
     Since the first fan  91  blows air toward a surface (upper side) of the foil film F for a sheet S to be laid thereon, the need for making a space for the first fan  91  or a duct to implement the air-blowing function, between the supply reel  31  and the take-up reel  35  can be obviated. Accordingly, space between the supply reel  31  and the take-up reel  35  can be minimized to the extent necessary and practical, with the result that upsizing of the film unit FU can be restrained. 
     Since the opening  21 A of the housing main body  21  faces upward, the film unit FU can be installed from above into the housing main body  21  and removed upward from the housing main body  21 . It is to be understood that, for example, in an alternative configuration which requires a film unit to be installed in and removed from the housing main body in horizontal directions, a user should withstand the pull of gravity to keep the film unit in horizontal position when handling the film unit for installation or removal. In contrast, the above-described configuration which allows the film unit FU to be installed from above into the housing main body  21  and removed upward from the housing main body  21  does not require a user to withstand the pull of gravity to keep the film unit FU in horizontal position; therefore, the installation and removal can be done without difficulty. Furthermore, in the configuration which requires a film unit to be installed in and removed from the housing main body in horizontal directions, the film unit when installed or removed tends to sway from a specified (desired) position to an inclined position by the pull of gravity; therefore, the film unit is likely to interfere with members in the housing main body. In contrast, the above-described configuration which allows the film unit FU to be installed from above into the housing main body  21  and removed upward from the housing main body  21  makes the film unit FU unlikely to sway from a specified position to an inclined position, and thus can restrain the film unit FU from interfering from the members in the housing main body  21 . 
     Since the cover  22  includes the first fan  91 , the housing main body  21  can be downsized in comparison, for example, with an alternative configuration in which the housing main body includes a first fan. 
     Since the air intake  22 B is provided in the side surface  22 A of the cover  22 , any liquid which would adhere to the upper surface of the cover  22  can be restrained form flowing into the housing main body  21 , in comparison, for example, with an alternative configuration in which the air intake is provided in the upper surface of the cover. 
     Since the first fan  91  is located upstream of the heating roller  61  in the direction of conveyance of a sheet S, the first fan  91  is located at the back of the housing  2  of the typical foil transfer device  1  (of which the ejection port for a sheet S faces toward the front, i.e., user&#39;s side), and is thus remote from the user; therefore, the source of noise can be located away from the user whose discomfort from the noise can thus be alleviated. 
     Since the air outlet D 11  formed in the first duct D 1  extends across the width of the foil film F (from one end to the other throughout its width), air can be caused to blow on the overall widths of the foil film F and the sheet S; therefore, the foil film F and the sheet S can be cooled efficiently. 
     Since the second fan  92  configured to force out air around the foil film F positioned between the heating roller  61  and the second guide shaft  42  is provided, the foil film F and the sheet S positioned between the heating roller  61  and the second guide shaft  42  can be cooled efficiently. 
     Since the first fan  91  is a sirocco fan, air sucked in from a side thereof facing in the axial direction can be forced out in a radial direction; therefore, air taken into the first duct D 1  through the air intake  22 B formed in the side surface  22 A of the cover  22  can be effectively forced out in the downstream direction of conveyance of a sheet S. 
     Since the second fan  92  is an axial fan, the quantity of air can be made greater, in comparison, for example, with an alternative configuration in which the second fan is a sirocco fan; therefore, the foil film F and a sheet S can be cooled more efficiently. 
     Since the second duct D 2  through which to guide air around the power supply board EB to the second fan  92  is provided, the power supply board EB can be cooled down. 
     Since the first temperature detector SE 1  is located in a position behind the foil film F such that the foil film F overlaps the first temperature detector SE 1  when the upper side of the foil film F positioned between the heating roller  61  and the second guide shaft  42  on which the sheet S is to be laid is viewed straight on in a direction perpendicular thereto, the adverse effect of air from the first fan  91  on the first temperature detector SE 1  can be reduced. 
     It is understood that space between the heating roller  61  and the second guide shaft  42  is subjected to the influence of heat derived from the foil F and the sheet S heated by the heating roller  61 , and is thus likely to become hotter than the space upstream of the heating roller  61 . Since the thermostat (first temperature detector SE 1 ) is provided in such a location of which the temperature is likely to go up, the thermostat can be activated quickly without delay. 
     Since the foil film F of the film cartridge FC of any kind installed in the housing main body  21  overlaps the first temperature detector SE 1  when an upper side of the foil film F positioned between the heating roller  61  and the second guide shaft  42  is viewed straight on in a direction perpendicular thereto, the adverse effect of air from the first fan  91  on the first temperature detector SE 1  can be reduced irrespective of the kind of the film cartridge FC. 
     Since each of the thermistors SE 21 , SE 22 , SE 23  is located upstream of the heating roller  61  and the pressure roller  51 , the air current blowing against the sheet S or the foil film F positioned between the heating roller  61  and the second guide shaft  42 , which would otherwise tend to move toward the thermistors SE 21 , SE 22 , SE 23 , should get blocked by the heating roller  61  and the pressure roller  51 ; therefore, the thermistors SE 21 , SE 22 , SE 23  can be prevented from suffering from the adverse effects of the air current. 
     Since the thermistors SE 21 , SE 22 , SE 23  are located in positions different from each other in the across-the-width direction, different portions of the heating roller  61  arranged in the across-the-width direction can be detected by the thermistors SE 21 , SE 22 , SE 23 . 
     It is to be understood that the present embodiment can be modified into various other forms as described below, for practical application. 
     In the above-described embodiment, the first fan  91  is configured to blow air toward the surface of the foil film F for a sheet S to be laid thereon; however, the first fan  91  may alternatively be configured to blow air toward the surface of the foil film F on the reverse side of the surface for a sheet S to be laid thereon, or in a direction across the width of the foil film. 
     In the above-described embodiment, the first fan  91  is provided in the cover  22 , and the second fan  92  is provided in the housing main body  21 ; however, the first fan and the second fan may be located in any positions within the housing. 
     In the above-described embodiment, the first fan  91  is a sirocco fan, and the second fan  92  is an axial fan; however, the first fan and the second fan may be any type of fan. 
     In the above-described embodiment, the first duct D 1  and the second duct D 2  are provided; however, the duct(s) may not necessarily be provided. 
     In the above-described embodiment, the first temperature detector SE 1  is a thermostat, and the second temperature detector SE 2  is a thermistor; however, for example, the first temperature detector may be a thermistor, and/or the second temperature detector may be a thermostat. 
     A detailed description will be given of a second embodiment with reference made mainly to  FIGS. 8 to 15 . In the following description, elements having substantially the same configurations are designated by the same reference characters, and a duplicate description thereof will be omitted. 
     As shown in  FIG. 8 , a foil transfer device  1  according to the second embodiment is capable of executing a foil transfer process in which a sheet S having a toner image formed thereon is laid on a foil film F and conveyed to cause a transfer layer to be transferred onto the toner image formed on the sheet S. The foil transfer device  1  includes a housing  2 , a sheet tray  3 , a sheet conveyor unit  10 , a film supply unit  30 , a transfer unit  50 , a controller  80 , a fan  90 , and a motor  95 . 
     The housing  2  is made of plastic or the like, and includes a housing main body  21  and a cover  22 . The housing main body  21  has an opening  21 A at its upper side (see  FIG. 9 ). The opening  21 A has a size large enough to allow a film unit FU to pass therethrough. The housing main body  21  further includes a first guide GD 1  and a second guide GD 2 , which hold the film unit FU in a manner that permits the film unit FU to be installed into and removed from the housing main body  21 . The cover  22  is a member for opening and closing the opening  21 A. A rear end portion of the cover  22  is rotatably supported by the housing main body  21 . The cover  22  is configured to be swingable between a closed position in which the opening  21 A is closed (position shown in  FIG. 8 ) and an open position in which the opening  21 A is open (position shown in  FIG. 9 ). 
     The sheet tray  3  is provided with a sheet sensor  3 A. The seat sensor  3 A is swingable to a non-detection position indicated by a solid line and to a detection position indicated by a chain line, and capable of detecting whether or not a sheet S is placed on the sheet tray  3 . 
     The sheet conveyor unit  10  includes a sheet feed mechanism  11  and a sheet ejection mechanism  12 . The sheet feed mechanism  11  includes a pickup roller  11 A and a retard roller  11 B. The sheet ejection mechanism  12  includes a plurality of conveyor rollers and a sheet sensor  12 A. The sheet sensor  12 A is swingable to a non-detection position indicated by a solid line and to a detection position indicated by a chain line, and capable of detecting whether or not a sheet S has been ejected completely. 
     The film supply unit  30  includes a film unit FU and a motor  95 . The film unit FU includes a supply reel  31 , a take-up reel  35 , a first guide shaft  41 , a second guide shaft  42  as an example of a separator, and a third guide shaft  43 . A foil film F is wound on the supply reel  31  of the film unit FU. As shown in  FIG. 9 , the film unit FU is configured to be installable into and removable from the housing main body  21  through the opening  21 A in a direction perpendicular to an axial direction of the supply reel  31 . 
     As shown in  FIG. 10  and  FIG. 11 , in the present embodiment, the second guide shaft  42  includes a shaft  42 A made of stainless steel, and a cover  42 B made of plastic. The shaft  42  is covered with the covered  42 B. A third temperature detector  81  is provided at the second guide shaft  42 . The third temperature detector  81  is capable of detecting a temperature of the second guide shaft  42 . 
     The third temperature detector  81  is a thermistor in contact with the second guide shaft  42 . In the present embodiment, the third temperature detector  81  is in contact with the cover  42 B. The third temperature detector  81  is located in a position within a region H 4  coextensive, in an axial direction of the second guide shaft  42 , with a path of a foil transferable minimum-sized sheet S allowed to be conveyed in the foil transfer device  1 . 
     Turning back to  FIG. 8 , the transfer unit  50  includes a pressure roller  51  and a heating member  60 . The heating member  60  includes a heating roller  51  and a heater  62 . 
     In the vicinity of the heating roller  61 , a second temperature detector  82  capable of detecting a temperature of the heating roller  61  is provided (see  FIG. 10 ). In the present embodiment, the second temperature detector  82  is a noncontact thermistor that is kept out of contact with the heating roller  61 . It is to be understood that the second temperature detector  82  may be of a contact type. 
     The foil transfer device  1  includes a contact/separation mechanism  70  configured to cause the heating roller  61  to move between a contact position in which the heating roller  61  is in contact with the foil film F and a separate position in which the heating roller  61  is separate from the foil film F. The contact/separation mechanism  70  is configured such that when the cover  22  is in a closed state and the controller  80  executes a foil transfer control process, the heating roller  61  is moved to the contact position and brought into contact with the foil film F. Furthermore, the contact/separation mechanism  70  is configured such that when the cover  22  is open or when the process of transferring foil onto a sheet S is not executed in the transfer unit  50 , the heating roller  61  is kept in the separate position separate from the foil film F. 
     The controller  80  includes a central processing unit (CPU), a read-only memory (ROM), a random-access memory (RAM), a non-volatile memory, etc., and is configured to execute a variety of control processes based on computer programs prepared in advance. Data necessary for the foil transfer control, such as control tables suitable for respective foil films F of the film cartridges F installable in the housing main body  21  are stored in the ROM, the non-volatile memory, etc. When the process of transferring foil onto a sheet S is performed, a user may, for example, operate a control panel  85  provided on the cover  22  of the housing  2 , to configure and run a desired foil transfer job. The controller  80  receives a signal from the control panel  85 , and executes a foil transfer control process corresponding to the job configured by the user. 
     The fan  90  is an air blower capable of producing a current of air within the housing main body  21  (i.e., forcing air within the housing main body  21  to flow). In the present embodiment, the fan  90  is provided within the housing main body  21 . 
     Next, the outline of a control process executed by the controller  80  after the power to the foil transfer device  1  is turned on is explained. 
     When the power to the foil transfer device  1  is turned on, the controller  80  turns the heater  62  on, with the target temperature for the heating roller  61  being set at a ready temperature TR. The ready temperature TR may be set as desired. In the present embodiment, the ready temperature TR is equal to 100 degrees centigrade (TR=100° C.). Once the temperature detected by the second temperature detector  82  exceeds 100° C., the controller  80  performs a feedback control over the heater  62  to keep the detected temperature at 100° C. 
     Upon receipt of a foil transfer instruction, the controller  80  executes a foil transfer control process. 
     For the foil transfer control process, the controller  80  sets the target temperature for the heating roller  61  at a first target temperature TH that is higher than the ready temperature TR. The first target temperature TH is a temperature fit for precise transfer of the transfer layer of the foil film F onto a toner image formed on a sheet S. The first target temperature TH may be set as desired according to the kinds of the transfer layers, or the like. In the present embodiment, the first target temperature TH is equal to 150 degrees centigrade (TH=150° C.). Once the temperature detected by the second temperature detector  82  exceeds 150° C., the controller  80  performs a feedback control over the heater  62  to keep the detected temperature at 150° C. 
     If the controller  80  finds that a temperature acquired from the second temperature detector  82  has reached the first target temperature TH, the controller  80  activates the motor  95  and causes the heating roller  61  to move to the contact position. Consequently, a sheet S on the foil film F is conveyed (i.e., the sheet S and the foil film F passes through between the heating roller  61  and the pressure roller  51 ) so that the foil transfer process is executed. If the controller  80  finds that the sheet S has been ejected completely and no subsequent sheet S remains on the sheet tray  3 , the controller  80  causes the heating roller  61  to move to the separate position and stops the motor  95 , thereby bringing the foil transfer process to an end. 
     If a temperature acquired from the third temperature detector  81  is equal to or higher than a first temperature T 1 , the controller  80  executes a first cooldown process to cool the second guide shaft  42 . In the present embodiment, the first temperature T 1  is equal to 70 degrees centigrade (T 1 =70° C.). 
     After starting the first cooldown process, the controller  80  monitors the temperature acquired from the third temperature detector  81 , and brings the first cooldown process to an end on condition that the temperature acquired from the third temperature detector  81  has become lower than a second temperature T 2  that is lower than the first temperature T 1 . In the present embodiment, the second temperature T 2  is equal to 60 degrees centigrade (T 2 =60° C.). 
     The controller  80  may be configured to suspend a foil transfer control process for the first cooldown process. If the foil transfer control process has been suspended before commencement of the first cooldown process, the controller  80  restarts the suspended foil transfer control process after the end of the first cooldown process. 
     The controller  80  is configured to cause the fan  90  to revolve at a second speed V 2  slower than a first speed V 1  (the speed at which the fan  90  is caused to revolve during the first cooldown process) before the temperature acquired from the third temperature detector  81  has become equal to or higher than the first temperature T 1 . To be more specific, the controller  80  is configured to cause the fan  90  to revolve at the second speed V 2  if the temperature acquired from the third temperature detector  81  is equal to or higher than a third temperature T 3  lower than the first temperature T 1 . 
     The controller  80  is configured to stop the fan  90  if the temperature acquired from the third temperature detector  81  has become lower than a temperature that is lower than the second temperature T 2  and lower than the third temperature T 3 . 
     The third temperature T 3  may be either a temperature not lower than the second temperature T 2  or a temperature lower than the second temperature T 2 . In the present embodiment, the third temperature T 3  is 65° C., that is, lower than the first temperature T 1  and higher than the second temperature T 2 . In the present embodiment, the first speed V 1  is a full speed that is the fastest possible speed of the fan  90 , while the second speed V 2  is a half speed that is half the full speed of the fan  90 . 
     The first cooldown process is a process which may include a process of reducing an amount of conveyance of sheets S per unit time and/or a process of causing the fan  90  to revolve at the first speed V 1 . 
     The process of reducing an amount of conveyance of sheets per unit time is a process by which the foil transfer duty is lowered. To be more specific, as the process of reducing the amount of conveyance of sheets S per unit time, the controller  80  executes either one or both of the following two processes: a process of lengthening an interval between times at which sheets S are to be conveyed; and a process of slowing the speed of conveyance of the sheets S. The process of lengthening a interval between times at which sheets S are to be conveyed may include suspending the conveyance of sheets S. When the conveyance of sheets S is to be suspended, the controller  80  may continue the foil transfer process in the interim for the sheets S remaining in the housing main body  21  and already being subjected to the foil transfer process, until these sheets S are ejected to the outside of the housing main body  21 . 
     In the present embodiment, the controller  80  is configured to cause the fan  90  to revolve at the first speed V 1  and suspend the supply/conveyance of sheets S, for the first cooldown process. After causing sheets S, if any, remaining in the housing main body  21 , to be ejected to the last, the controller  80  causes the heating roller  61  to move to the separate position, and turns off the motor  95 . In other words, the controller  80  is configured to execute the first cooldown process in a state where the heating roller  61  is separate from the foil film F. 
     The controller  80  is further configured to execute a second cooldown process to cool the heating roller  61  down if the temperature acquired from the second temperature detector  82  is equal to or higher than a fourth temperature T 4  that is higher than the first temperature T 1 . In the present embodiment, the fourth temperature T 4  is equal to 195 degrees centigrade (T 4 =195° C.). 
     After starting the second cooldown process, the controller  80  monitors the temperature acquired from the second temperature detector  82 , and brings the second cooldown process to an end on condition that the temperature acquired from the second temperature detector  82  has become lower than a fifth temperature T 5  that is lower than the fourth temperature T 4 . In the present embodiment, the fifth temperature T 5  is equal to 160 degrees centigrade (T 5 =160° C.). 
     In the present embodiment, the second cooldown process is substantially the same process as the first cooldown process, and a duplicate description thereof will be omitted. 
     Next, referring to flowcharts shown in  FIGS. 12 to 15 , a description will be given of one example of the process of the controller  80  according to the present embodiment The flowcharts of  FIG. 12  and  FIG. 13  show the process steps of a foil transfer control process to be executed upon power-up. 
     As shown in  FIG. 12 , upon power-up of the foil transfer device  1 , the controller  80  turns on the heater  62  with the target temperature for the heating roller  61  being set at the ready temperature TR (S 3 ). The controller  80  makes a determination as to whether a foil transfer instruction is received (S 4 ). 
     If it is determined in step S 4  that no foil transfer instruction is received (No in step S 4 ), then the controller  80  brings the process to an end. 
     If it is determined in step S 4  that a foil transfer instruction has been received (Yes in step S 4 ), then the controller  80  executes the foil transfer control process (S 5 ), and eventually brings the process to an end. 
     Next, the foil transfer control process is discussed in detail. 
     As shown in  FIG. 13 , at the start of the foil transfer control, the controller  80  sets the target temperature for the heating roller  61  at a first target temperature TH (S 11 ). 
     After step S 11 , the controller  80  makes a determination as to whether or not the temperature of the heating roller  61  is equal to or higher than the first target temperature TH, i.e., the temperature detected by means of the second temperature detector  82  is equal to or higher than the first target temperature TH (S 12 ). 
     If it is determined in step S 12  that the temperature of the heating roller  61  is not equal to or higher than the first target temperature TH (No, in step S 12 ), then the controller  80  waits until the temperature of the heating roller  61  becomes equal to or higher than the first target temperature TH. 
     On the other hand, if it is determined in step S 12  that the temperature of the heating roller  61  is equal to or higher than the first target temperature TH (Yes in step S 12 ), then the controller  80  activates the motor  95 , and causes the heating roller  61  which is connected to the motor  95  via a gear train (not shown) to rotate (S 13 ). The controller  80  further causes a mechanical force produced by the motor  95  to be transmitted to the contact/separation mechanism  70  which in turn causes the heating roller  61  to move to the contact position (S 14 ). 
     In sync with the process in step S 14 , the controller  80  causes a sheet S to be fed onto and conveyed with the foil film F (S 15 ) to perform a foil transfer. 
     After step S 15 , the controller  80  makes a determination as to whether or not the sheet S has been ejected completely (S 16 ), and if it is determined in step S 16  that the sheet S has not yet been ejected completely (No in step S 16 ), then the controller  80  waits until the sheet S has been ejected completely, while if it is determined in step S 16  that the sheet S has been ejected completely (Yes in step S 16 ), then the controller  80  makes a determination as to whether or not sheet(s) S still remains on the sheet tray  3  (S 17 ). 
     If it is determined in step S 17  that one or more sheets S still remain on the sheet tray  3  (Yes in step S 17 ), then the controller  80  repeats the process steps starting from step S 15  to continue to execute the foil transfer process. 
     If it is determined in step S 17  that no sheet S remains on the sheet tray  3  (No in step S 17 ), then the controller  80  causes the heating roller  61  to move to the separate position (S 18 ), turns off the motor  95  (S 19 ), and brings the foil transfer control process to an end. 
     Referring now to the flowcharts of  FIG. 14  and  FIG. 15 , a description will be given of a process, executed after the power-up, for the cooldown process. When the foil transfer device  1  is being powered, the controller  80  repeatedly executes the process steps S 21  to S 32 . 
     As shown in  FIG. 14 , the controller  80  makes a determination as to whether or not the temperature of the heating roller  61  is equal to or higher than the fourth temperature T 4  (S 21 ). If it is determined in step S 21  that the temperature of the heating roller  61  is equal to or higher than the fourth temperature T 4  (Yes in step S 21 ), then the controller  80  proceeds to execute the cooldown process (S 30 ). 
     On the other hand, if it is determined in step S 21  that the temperature of the heating roller  61  is not equal to or higher than the fourth temperature T 4  (No in step S 21 ), then the controller  80  makes a determination as to whether or not the temperature of the second guide shaft  42  (separator) is equal to or higher than the first temperature T 1 , i.e., the temperature detected by means of the second temperature detector  82  is equal to or greater than the first target temperature TH (S 22 ). 
     If it is determined in step S 22  that the temperature of the second guide shaft  42  is equal to or higher than the first temperature T 1  (Yes in step S 22 ), then the controller  80  proceeds to execute the cooldown process (S 30 ), and if it is determined in step S 22  that the temperature of the second guide shaft  42  is not equal to or higher than the first temperature T 1  (No in step S 22 ), then the controller  80  makes a determination as to whether or not the temperature of the second guide shaft  42  is equal to or higher than the third temperature T 3  (S 23 ). 
     If it is determined in step S 23  that the temperature of the second guide shaft  42  is equal to or higher than the third temperature T 3  (Yes in step S 23 ), then the controller  80  causes the fan  90  to revolve at the second speed V 2  (S 24 ), and brings the process to an end. 
     On the other hand, if it is determined in step S 23  that the temperature of the second guide shaft  42  is not equal to or higher than the third temperature T 3  (No in step S 23 ), then the controller  80  makes a determination as to whether or not the fan  90  is revolving (S 25 ). If it is determined in step S 25  that the fan  90  is revolving (Yes in step S 25 ), then the controller  80  stops the fan  90  (S 26 ), while if it is determined in step S 25  that the fan  90  is not revolving (No in step S 25 ), then the controller  80  brings the process to an end. 
     After step S 30 , the controller  80  makes a determination as to whether or not the foil transfer control was in process before commencement of the first cooldown process (S 31 ). 
     If it is determined in step S 31  that the foil transfer control was not in process before commencement of the first cooldown process (No in step S 31 ), then the controller  80  brings the process to an end. 
     If it is determined in step S 31  that the foil transfer control was in process before commencement of the first cooldown process (Yes in step S 31 ), then the controller  80  restarts the suspended process, that is, the foil transfer control (S 32 ), and brings this process to an end. 
     Next, the cooldown process will be described. 
     As shown in  FIG. 15 , to execute the cooldown process, the controller  80  causes the fan  90  to revolve at a first speed V 1  (S 41 ), and makes a determination as to whether the foil transfer control is in process (S 42 ). 
     If it is determined in step S 42  that the foil transfer control is not in process (No in step S 42 ), then the controller  80  proceeds to execute the process in step S 46 , while if it is determined in step S 42  that the foil transfer control is in process (Yes in step S 42 ), then the controller  80  makes a determination as to whether or not there is any sheet(s) S remaining on the sheet tray  3  (S 43 ). 
     If it is determined in step S 43  that there is one or more sheets S on the sheet tray  3  (Yes in step S 43 ), then the controller  80  suspends the sheet feed operation (S 44 ), and proceeds to step S 45 . 
     If it is determined in step S 43  that there is no sheet S on the sheet tray  3  (No in step S 43 ), or after completion of the process in step S 44  (if determination in step S 43  turns out to be Yes), the controller  80  makes a determination as to whether or not the sheet eject operation has been completed, i.e., whether or not there is any sheet(s) S already fed but not yet ejected completely (S 45 ). 
     If it is determined in step S 45  that the sheet eject operation has not been completed (No in step S 45 ), then the controller  80  waits until the sheet eject operation is complete, while if it is determined in step S 45  that the sheet eject operation has been completed (Yes in step S 45 ), then the controller  80  proceeds to execute the process in step S 46 . 
     The controller  80 , in step S 46 , exercises control over the contact/separation mechanism  70  to cause the heating roller  61  to move to the separate position (S 46 ). The controller  80  then turns off the motor  95  to stop rotation of the heating roller  61  (S 47 ), and makes a determination as to whether or not the temperature of the heating roller  61  is lower than the fifth temperature T 5  (S 48 ). 
     If it is determined in step S 48  that the temperature of the heating roller  61  is not lower than the fifth temperature T 5  (No in step S 48 ), then the controller  80  waits until the temperature of the heating roller  61  becomes lower than the fifth temperature T 5 . On the other hand, if it is determined in step S 48  that the temperature of the heating roller  61  is lower than the fifth temperature T 5  (Yes in step S 48 ), then the controller  80  makes a determination as to whether or not the temperature of the second guide shaft  42  (separator) is lower than the second temperature T 2  (S 49 ). 
     If it is determined in step S 49  that the temperature of the second guide shaft  42  is not lower than the second temperature T 2  (No in step S 49 ), then the controller  80  waits until the temperature of the second guide shaft  42  becomes lower than the second temperature T 2 . On the other hand, if it is determined in step S 49  that the temperature of the second guide shaft  42  is lower than the second temperature T 2  (Yes in step S 49 ), then the controller  80  brings the cooldown process to an end. 
     With the foil transfer device  1  as described above, the following advantageous effects can be achieved. 
     The foil transfer device  1  includes the second guide shaft  42  as a separator configured to separate the foil film F from the sheet S. If the second guide shaft  42  becomes hot (i.e., the temperature of the second guide shaft  42  becomes high), the transfer layer would soften up and lose crispness, and cause degradation in the quality of an image of the transferred foil. 
     With this in view, the foil transfer device  1  includes the third temperature detector  81  capable of detecting the temperature of the second guide shaft  42 , and the controller  80  executes the first cooldown process in which if the temperature acquired from the third temperature member  81  is equal to or higher than the first temperature T 1 , the second guide shaft  42  is cooled down. Therefore, the second guide shaft  42  is restrained from becoming too hot, and the degradation in the quality of an image formed with the transferred foil can be restricted. 
     Since the controller  80  starting the first cooldown process delays the end of the first cooldown process until the temperature acquired from the third temperature detector  81  becomes lower than the second temperature T 2  that is lower than the first temperature T 1 , an undesirable rise in the temperature of the second guide shaft  42  back to the first temperature T 1  or even higher shortly after the end of the first cooldown process can be made unlikely to take place. 
     Since the controller  80  executing the first cooldown process causes the heating roller  61  to be separated from the foil film F, the execution time of the first cooldown process can be shortened. 
     Further, the controller  80  executes the second cooldown process in which if the temperature acquired from the second temperature detector  82  is equal to or higher than the fourth temperature T 4  that is higher than the first temperature T 1 , the heating roller  61  is cooled down. Accordingly, the heating roller  61  is restrained from becoming too hot, and the degradation in the quality of an image formed with the transferred foil can be restricted. 
     Since the second guide shaft  41  has the plastic cover with which the metal shaft is covered, inadvertent contact of a user with the second guide shaft  41  would not make the user hurt so seriously by heat. 
     The third temperature detector  42  is located in a position within a region H 4  coextensive, in an axial direction of the second guide shaft  42 , with a path of a foil transferable minimum-sized sheet allowed to be conveyed in the foil transfer device  1 . Accordingly, the third temperature detector  81  can acquire the temperature of a portion at which the foil is transferred, with the result that the temperature can be controlled adequately. 
     Next, a third embodiment will be described below. 
     The second embodiment described above includes the controller  80  which causes the fan  90  to revolve at the second speed V 2  that is slower than the first speed V 1 , if the temperature acquired from the third temperature detector  81  is equal to or higher than the third temperature T 3  that is lower than the first temperature T 1 . In contrast, the third embodiment is different from the second embodiment in that the fan  90  is caused to revolve at the second speed V 2  on condition that the power has been turned on. 
     Further, in the third embodiment, even if the temperature of the second guide shaft  42  becomes lower than the third temperature T 3 , the fan  90  is not stopped and caused to revolve at the second speed V 2 . Similarly, even after the end of the first cooldown process or the second cooldown process, the fan  90  is not stopped and caused to revolve at the second speed V 2 . 
     Referring now to the flowcharts shown in  FIG. 16  and  FIG. 17 , one example of the process of the controller  80  according to the third embodiment will be described below. In describing the flowchart of  FIG. 16 , only the steps different from those of the process shown in  FIG. 12  are brought into focus; in describing the flowchart of  FIG. 17 , only the steps different from those of the process shown in  FIG. 14  are brought into focus. 
     As shown in  FIG. 16 , in the third embodiment, when the power to the foil transfer device  1  is turned on, the controller  80  causes the fan  90  to revolve at the second speed V 2  (S 2 ). Following the step S 2 , the controller  80  executes the same process steps as in the second embodiment. 
     As shown in  FIG. 17 , in the third embodiment, if it is determined in step S 22  that the temperature of the second guide shaft  24  is not equal to or higher than the first temperature T 1  (No in step S 22 ), then the controller  80  brings the process to an end. 
     Further, in the third embodiment, if it is determined in step S 31  that the foil transfer control was not in process before commencement of the first cooldown process or the second cooldown process (No in step S 31 ), or (if the foil transfer control was in process which has temporarily been suspended) after restarting the suspended foil transfer control process in step S 32 , the controller  80  causes the fan  90  to revolve at the second speed V 2  (S 35 ), and brings the process to an end. 
     In this third embodiment, like the second embodiment, the second guide shaft  42  can be restrained from becoming too hot, i.e., equal to or higher than the first temperature T 1 , and thus the degradation in the quality of an image formed with the transferred foil can be restricted. 
     The second embodiment and the third embodiment as described above may be modified where appropriate in specific configurations. 
     For example, although the second embodiment and the third embodiment are configured to have the second guide shaft  42  as an example of the separator made up of the shaft  42 A of stainless steel and the cover  42 B of plastic, and the shaft  42 A is covered with the cover  42 B, the shaft may not necessarily be made of stainless steel, but may be of other kind of metal, or even of a material other than metal. Furthermore, the cover with which the shaft is covered may not be provided. In this alternative configuration, the third temperature detector may be in contact with the shaft which may be made of stainless steel or other material. 
     Although the second embodiment and the third embodiment are each configured to have a thermistor as the third temperature detector or the second temperature detector, each of the third temperature detecting sensor and the second temperature sensor may be an infrared sensor or a thermocouple. 
     In the above described embodiments, the sheet sensor  3 A provided at the sheet tray  3  and the sheet sensor  12 A provided at the sheet ejection mechanism  12  are each illustrated as a contact-type sensor contactable with a sheet S, but the sheet sensor  3 A and the sheet sensor  12 A may be of a noncontact type. 
     In the above described embodiment, the second cooldown process is described as substantially the same process as the first cooldown process, but the second cooldown process may be different from the first cooldown process. 
     Although the second embodiment and the third embodiment are each configured to have the fan  90  provided within the housing main body, the fan may be provided at any position within the housing, for example, within the cover, outside of the housing main body or outside of the cover, as long as the fan can produce a current of air (to force air to flow) within the housing. To force air to flow within the housing, a single fan may suffice, but more than one fan may be provided where appropriate. 
     For example, in a specific configuration illustrated as the first embodiment with the first fan  91  configured to blow air toward the foil film F positioned between the heating member (heating roller  61 ) and the separator (second guide shaft  42 ), as well, the third temperature detector  81  capable of detecting the temperature of the separator and the controller configured to execute the cooldown process based on the temperature acquired from the third temperature detector may be provided. 
     Further, the control exercised by the controller to execute the cooldown process may be implemented in a configuration having no third temperature detector  81  capable of detecting the temperature of the separator. The following description of a fourth embodiment, made with reference to  FIG. 18 , is directed to one example of a control process in an exemplary configuration having the first fan  91  and the second fan  92  as described in the first embodiment but not having the third temperature detector capable of detecting the temperature of the separator. 
     In this embodiment shown in  FIG. 18 , the controller  80  utilizes a heating roller temperature THe (the temperature of the heating roller  61  as acquired from the second temperature detector  82 ), a set conveyance speed VSt, a foil transfer sheet number NSt (the number of sheets as counted based on a signal generated by the sheet sensor  12 A detecting a sheet S being ejected), and a foil transfer job interval Fi (the idle time between foil transfer jobs), to estimate a temperature of the separator. Herein, the foil transfer sheet number NSt is the number of sheets subjected to the foil transfer process executed continuously without suspension as effected by the cooldown process. The foil transfer job refers to a unit foil transfer process executed continuously on a batch of sheets (sheets of which the number is set by a user or all the sheets placed on the sheet tray  3 ) until all the sheets in the batch are conveyed and processed for foil transfer. 
     In this embodiment, the timing of activation of the first fan  91  and the second fan  92  under the foil transfer control is determined based on the estimated separator temperature obtained by Eq. 1: 
       Estimated separator temperature= A×THe+B×NSt×VSt+C×Fi    Eq. 1
 
     where A is a coefficient determined by a contribution rate of the heating roller temperature THe to the separator temperature (temperature rise factor); B is a coefficient determined by a contribution rate of sheets going past the separator at the conveyance speed VSt to the separator temperature per the foil transfer number NSt (temperature rise factor); C is a coefficient determined by a contribution rate of the foil transfer job interval Fi to the separator temperature (heat dissipation factor). The coefficients A and B are positive constants, and the coefficient C is a negative constant. The coefficients A, B and C are predetermined based on simulation or the like and stored in advance. The variables THe, NSt, VSt, and Fi for estimation of the separator temperature are stored in advance and updated on as-needed basis. 
     In the foil transfer device  1  according to the present embodiment, the controller  80  uses an interval flag FFi to make a determination at the start of a foil transfer job as to whether it is the first job to be executed for the first time after the power-up of the foil transfer device  1  or there has been a preceding job executed previously. The controller  80  has a region for the interval flag FFi in its nonvolatile memory, and is configured to set “0” upon powering off, and to set “1” at the time of execution of the foil transfer job. In addition, the controller  80  stores a predetermined value as a foil transfer job interval Fi upon power-up i.e., an initial value to be set when the power is turned on. 
     At the start of the foil transfer control process, in order to determine a value of the foil transfer job interval Fi, the controller  80  first confirms whether or not the interval flag FFi is set at “1” (S 51 ). If it is confirmed No in step S 51  i.e., FFi is not “1” (No, in step S 51 ), then the controller  80  sets the foil transfer job interval Fi at the initial value and sets the interval flag FFi at “1” (S 52 ). On the other hand, if FFi=1 in step S 51  (Yes in step S 51 ), then the controller  80  loads the counted (measured) foil transfer job interval Fi into its RAM (S 53 ). 
     The controller  80  counts up (increments) the foil transfer sheet number NSt each time when a sheet S has been ejected, based on a signal generated by the sheet sensor  12 A detecting the sheet S (S 54 ), and estimates the separator temperature (S 55 ). Here, the controller  80  uses the foil transfer job interval Fi determined as described above and the foil transfer sheet number NSt counted as described above, as well as the values of the heating roller temperature THe and the conveyance speed VSt, to estimate the separator temperature, based on Eq. 1. 
     Subsequently, the controller  80  makes a determination as to whether or not the estimated separator temperature is lower than a first temperature T 1  (S 56 ). If the separator temperature turns out to be not lower than the first temperature T 1  (No in step S 56 ), then the controller  80  suspends the foil transfer control process (S 57 ), and executes the cooldown process to cause the fans  91 ,  92  to revolve at full speeds (S 58 ), and then brings the process back to step S 56 . 
     On the other hand, if the separator temperature turns out to be lower than the first temperature T 1  (Yes in step S 56 ), then the controller  80  makes a determination as to whether or not the fans  91 ,  92  are revolving (S 61 ). If it turns out that the fans  91 ,  92  are not revolving (No in step S 61 ), then the process goes to S 65 ; if it turns out that the fans  91 ,  92  are revolving (Yes in step S 61 ), then the controller stops the fans  91 ,  92  (S 62 ), resets the foil transfer sheet number count to “0” (S 63 ), restarts the suspended foil transfer process (S 64 ), and then proceeds to step S 65 . The operations restarted in step S 64  include the restart of heating by the motor  95  causing the heating roller  61  to rotate and the contact/separation mechanism  70  to move the heating roller  61  to the contact position in which the heating roller  61  is in contact with the foil film F, the restart of supplying the foil film F by the film supply unit  30 , and the restart of conveying a sheet S by the sheet conveyor unit  10 . 
     In step S 65 , the controller  80  makes a determination as to whether or not the foil transfer job has been completed, and if it turns out that the foil transfer job has not been completed (No in step S 65 ), then goes back to step S 54 , executing the foil transfer process for the subsequent sheet S, and estimates the separator temperature (S 54 ), to make a determination as to whether a cooldown process is necessary. 
     If it is determined in step S 65  that the foil transfer job has been completed (Yes in S 65 ), then the controller  80  resets the counts of the foil transfer job interval Fi and the foil transfer sheet number NSt to “0” (S 66 ) and starts the count of the foil transfer job interval Fi (S 67 ), and brings the foil transfer control process for this foil transfer job to an end. 
     If the power to the foil transfer device  1  is not turned off, and a foil transfer control process for the subsequent foil transfer job is started, the interval flag FFi is set at “1” (Yes in step S 51 ); thus, the counted foil transfer job interval Fi is utilized (S 53 ). 
     In the fourth embodiment, the estimation made of the temperature of the second guide shaft  42  as the separator enables the cooldown process to be executed effectively for the second guide shaft  42 . In this way, the second guide shaft  42  can be restrained from becoming too hot, so that the degradation in the quality of an image formed with the transferred foil can be restricted. 
     It is to be understood that in a specific configuration with the first fan  91  and the second fan  92  as in the first embodiment, if it further includes the third detector capable of detecting the temperature of the separator, the control process can be executed without the steps S 55 , S 51  to S 54 , S 61 , and S 66  to S 67  in the flowchart of  FIG. 18 , for the separator temperature estimation and associated foil transfer job interval setting and counting and count-resetting of the foil transfer sheet number. 
     The above-described embodiments are configured as including the heating roller  61  for an element of the heating member, but the heating member may not include a heating roller but may include a film or a belt, instead. The heater  62  provided for an element of the heating member may not only be located inside the roller (or film or belt) but also be located outside the roller (or film or belt). 
     The process speed for fixing the transfer layer transferred on a sheet is not mentioned above and described on the premise that the process speed is not changed; however, the process speed may be changed depending on the kind of transfer layer (foil). Alternatively or additionally, the process speed may be changed depending on the material and/or thickness of the transfer layer. 
     For example, the controller  80  may be configured to make a determination as to whether or not the transfer layer includes a metal foil, and if it is determined that the transfer layer includes the metal foil, then sets the process speed at P 1 , and if it is determined that the transfer layer includes no metal foil, then sets the process speed at P 2  that is slower than P 1 . 
     In the above-described embodiments, the second guide shaft as the separator is provided in the film unit, but the second guide shaft may be provided in the housing main body. 
     In the above-described embodiments, the foil transfer device  1  is configured to have its heating member movable by means of the contact/separation mechanism, but alternatively, the pressure member may be configured to be movable, or both of the heating member and the pressure member may be configured to be movable, with a modified contact/separation mechanism. 
     In the above-described embodiments, the foil transfer device is configured to transfer a transfer layer onto a toner image formed on a sheet, but the foil transfer device may be configured otherwise as long as the foil transfer device transfers a transfer layer onto a sheet. For example, the foil transfer device may be configured to include a thermal head as a heating member. 
     In the above-described embodiments, the film cartridge FC is configured to be installable into and removable from the holder  100 , and the film cartridge FC installed in the holder  100  can be removably installable into the housing main body; however, the film cartridge may be configured to be removably installable directly in the housing main body. 
     In the above-described embodiments, a shaft-shaped member (second guide shaft  42 ) is illustrated as an example of the separator; however, the separator may be of a blade in the shape of a plate. 
     In the above-described embodiments, the pressure roller  51  is illustrated as an example of the pressure member; however, the pressure member may be a member including a belt and a pad. 
     In the above-described embodiments, the foil film F is configured to have four layers. However, the foil film may consist of any number of layers including a transfer layer and a supporting layer. 
     The elements described in the above embodiments and modified examples may be implemented selectively and in combination.