Patent Publication Number: US-6664999-B2

Title: Image-recording device and method

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an image-recording device which records an image on a printing plate and method. 
     2. Description of the Related Art 
     Devices which record (expose) an image on an image-forming layer (photosensitive layer), which is on a support of a sheet-form printing plate (for example, a “photopolymer plate”), with a direct light beam (a laser beam) have been developed as printing plate exposure devices (image-recording devices). 
     In a case in which the printing plate exposure device is, for example, a so-called CTP (computer-to-plate) printing plate exposure device, the light beam is irradiated at the printing plate from a collimator lens of a recording head (exposure head), through a condensing lens. In this case, if there is a variation of temperature at the recording head, a separation (distance) between the collimator lens and the condensing lens is changed due to thermal expansion of the recording head. Conventionally, in order to keep the magnification of a recorded image at a certain magnification, the light beam incident on the condensing lens from the collimator lens can be made to be parallel. With such a structure, even if the separation between the collimator lens and the condensing lens is altered, the magnification of the recorded image does not change undesirably. 
     However, in cases such as when an image resolution is switched in order to change image specification or the like, it is necessary to switch the magnification of the recorded image. To do this, it is necessary for the light beam incident on the condensing lens from the collimator lens to diverge. As a result, if the separation between the collimator lens and the condensing lens changes because of a change in temperature of the recording head, there is a problematic change in the magnification of the recorded image. 
     Moreover, when the temperature of the recording head changes, the recording head expands or contracts, and a separation between the recording head and the printing plate changes. Accordingly, a separation between the condensing lens and the printing plate changes. Consequently, there is a problem in that a shift of focus of the recorded image occurs. 
     In addition, when the temperature of the recording head changes, the collimator lens and the condensing lens expand or contract in accordance with changes of temperature of the collimator lens and the condensing lens. As a result, undesired alterations in an amount of divergence of the light beam by the collimator lens and a focusing distance of the light beam from the condensing lens are caused. Consequently, the problems of a change in the magnification and a shift of focus of the recorded image occur in combination. 
     SUMMARY OF THE INVENTION 
     In consideration of the circumstances described above, an object of the present invention is to provide an image-recording device and method which can prevent a shift in magnification of a recorded image regardless of temperature variations of a recording head, even when a light beam which is incident on a condensing lens is divergent, and an image-recording device and method which can prevent a shift of focus of a recorded image regardless of temperature variations of a recording head. 
     An image-recording device according to a first aspect of the present invention is an image-recording device that includes: a recording head which includes a transmission component which transmits a light beam, and a condensing lens at which the light beam transmitted from the transmission component is incident, the recording head recording an image at a printing plate by irradiating the light beam through the transmission component and the condensing lens to the printing plate; a measuring component which measures one of a temperature of the recording head or a temperature of a location which is presumed to be associated with the temperature of the recording head; and an adjustment component which adjusts a separation between the transmission component and the condensing lens on the basis of the temperature measured by the measuring component. 
     According to the image-recording device of the first aspect, an image is recorded on a printing plate by irradiating a light beam at the printing plate through the transmission component and the condensing lens of the recording head. 
     The measuring component measures the temperature of the recording head and/or the temperature of the location which is presumed to be associated with the temperature of the recording head. On the basis of the measured temperature, the adjustment component adjusts the separation between the transmission component and the condensing lens. As a result, the separation between the transmission component and the condensing lens can be kept constant by the adjustment component, regardless of contraction or expansion of the recording head due to temperature variations of the recording head. In addition, even if the temperature of the transmission component changes due to temperature variations of the recording head, such that the transmission component expands or contracts and thus an amount of divergence of the light beam from the transmission component is altered, the adjustment component can adjust the separation between the transmission component and the condensing lens, such that this alteration of the amount of divergence of the light beam incident on the condensing lens from the transmission component can be eliminated. 
     Accordingly, even when the light beam incident on the condensing lens from the transmission component is divergent, a shift in the magnification of the recorded image can be prevented regardless of temperature variations of the recording head (without controlling the temperature of the recording head (the transmission component)). 
     An image-recording device according to a second aspect of the present invention is an image-recording device that includes: a recording head which includes a condensing lens, the recording head recording an image at a printing plate by irradiating a light beam from the condensing lens to the printing plate; a measuring component which measures one of a temperature of the recording head or a temperature of a location which is presumed to be associated with the temperature of the recording head; and a focus adjustment component which adjusts a separation between the condensing lens and the printing plate on the basis of the temperature measured by the measuring component. 
     According to the image-recording device of the second aspect, an image is recorded on a printing plate by irradiating a light beam at the printing plate from the condensing lens of the recording head. 
     In this aspect, the measuring component measures the temperature of the recording head and/or the temperature of the location which is presumed to be associated with the temperature of the recording head. On the basis of the measured temperature, the focus adjustment component adjusts the separation between the condensing lens and the printing plate. As a result, even if, when the recording head expands or contracts due to temperature variations of the recording head, such that the separation between the recording head and the printing plate changes and hence the separation between the condensing lens and the printing plate changes, the separation between the condensing lens and the printing plate can be kept constant by the focus adjustment component. In addition, even if the temperature of the condensing lens changes due to temperature variations of the recording head, such that the condensing lens expands or contracts and thus a focusing distance of the light beam from the condensing lens is altered, the focus adjustment component can adjust the separation between the condensing lens and the printing plate, such that this alteration (shift) of the focusing distance of the light beam from the condensing lens can be eliminated. 
     Accordingly, even when the temperature of the recording head changes, a loss (shift) of focus of the recorded image can be prevented, without controlling the temperature of the recording head (the condensing lens). 
     A third aspect of the present invention is an image-recording method comprising the steps of: measuring one of a temperature of a recording head which includes a transmission component which transmits a light beam, and a condensing lens at which the light beam transmitted from the transmission component is incident, the recording head recording an image at a printing plate by irradiating the light beam through the transmission component and the condensing lens to the printing plate, or a temperature a location in the vicinity of the recording head; and adjusting at least one of a separation between the transmission component and the condensing lens and a separation between the condensing lens and the printing pate on the basis of the measured temperature. 
     A fourth aspect of the present invention is an image-recording device according to the first aspect further comprising: a storing section for storing data relating to relationship between the one of the temperature of the recording head or the temperature of the location which is presumed to be associated with the temperature of the recording head, and the separation between the transmission component and the condensing lens, wherein the adjustment component adjusts the separation between the transmission component and the condensing lens on the basis of the temperature measured by the measuring component and the stored data. 
     A fifth aspect of the present invention is an image-recording device according to the first aspect further comprising: a storing section for storing data relating to relationship among the one of the temperature of the recording head or the temperature of the location which is presumed to be associated with the temperature of the recording head, the separation between the transmission component and the condensing lens, and an amount of divergence of the light beam from the transmission component, wherein the adjustment component adjusts the separation between the transmission component and the condensing lens on the basis of the temperature measured by the measuring component and the stored data. 
     A sixth aspect of the present invention is an image-recording device according to the second aspect further comprising: a storing section for storing data relating to relationship between the one of the temperature of the recording head or the temperature of the location which is presumed to be associated with the temperature of the recording head, and the separation between the printing plate and the condensing lens, wherein the focus adjustment component adjusts the separation between the printing plate and the condensing lens on the basis of the temperature measured by the measuring component and the stored data. 
     A seventh aspect of the present invention is an image-recording device according to the second aspect further comprising: a storing section for storing data relating to relationship among the one of the temperature of the recording head or the temperature of the location which is presumed to be associated with the temperature of the recording head, the separation between the printing plate and the condensing lens, and a focus distance of the light beam from the condensing lens, wherein the focus adjustment component adjusts the separation between the printing plate and the condensing lens on the basis of the temperature measured by the measuring component and the stored data. 
     An eighth aspect of the present invention is an image-recording method according to the third aspect, further comprising the step of storing data relating to relationship between the one of the temperature of the recording head or the temperature of the location which is presumed to be associated with the temperature of the recording head, and the separation between the transmission component and the condensing lens, wherein the separation between the transmission component and the condensing lens is adjusted on the basis of the measured temperature and the stored data. 
     A ninth aspect of the present invention is an image-recording method according to the third aspect further comprising the step of storing data relating to relationship among the one of the temperature of the recording head or the temperature of the location which is presumed to be associated with the temperature of the recording head, the separation between the transmission component and the condensing lens, and an amount of divergence of the light beam from the transmission component, wherein the separation between the transmission component and the condensing lens is adjusted on the basis of the measured temperature and the stored data. 
     A tenth aspect of the present invention is an image-recording method according to the third aspect further comprising the step of storing data relating to relationship between the one of the temperature of the recording head or the temperature of the location which is presumed to be associated with the temperature of the recording head, and the separation between the printing plate and the condensing lens, wherein the separation between the printing plate and the condensing lens is adjusted on the basis of the temperature and the stored data. 
     An eleventh aspect of the present invention is an image-recording method according to the third aspect further comprising the step of storing data relating to relationship among the one of the temperature of the recording head or the temperature of the location which is presumed to be associated with the temperature of the recording head, the separation between the printing plate and the condensing lens, and a focus distance of the light beam from the condensing lens, wherein the separation between the printing plate and the condensing lens is adjusted on the basis of the temperature and the stored data. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic side view showing a printing plate automatic exposure device relating to an embodiment of the present invention. 
     FIG. 2 is a plan view showing a recording head relating to the embodiment of the present invention. 
     FIG. 3 is a side view showing a recording head relating to the embodiment of the present invention. 
     FIG. 4 is a side view showing principal elements of a variant example of the recording head relating to the embodiment of the present invention. 
     FIG. 5 is a side view showing a variant example of a location, at the recording head relating to the embodiment of the present invention, at which a temperature sensor is disposed. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows a side view of a printing plate automatic exposure device  10  relating to the present embodiment, which is structured with application of the image-recording device of the present invention. 
     The printing plate automatic exposure device  10  relating to the present embodiment is for so-called CTP (computer-to-plate) printing exposure device, and is a device which exposes (records) an image at an image-forming layer (a photosensitive layer/emulsion surface) on a support of a printing plate  12 , which is a photopolymer plate, a thermal plate or the like. The printing plate automatic exposure device  10  is divided into a conveyance guide unit  14 , a punching section  16  and an exposure section  18 . The punching section  16  and the exposure section  18  are disposed at a front side of the conveyance guide unit  14 , and the exposure section  18  is disposed at a lower side of the punching section  16 . 
     The conveyance guide unit  14  includes a feed guide  20  with a substantially square flat plate form and a discharge guide  22  with a substantially square flat plate form. A relative positional relationship between the feed guide  20  and the discharge guide  22  is set so as to form a laterally inclined V-shape. The conveyance guide unit  14  is structured to rotate by a predetermined angle around a central vicinity of FIG.  1 . The feed guide  20  and the discharge guide  22  can be selectively made to correspond to the punching section  16  or the exposure section  18  by this rotation. The printing plate  12  is fed to and loaded on the feed guide  20 . 
     The conveyance guide unit  14  is rotated and the feed guide  20  corresponds with (faces) the punching section  16 . Hence, a front end portion of the printing plate  12  on the feed guide  20  is conveyed into the punching section  16 , and a predetermined number of punch holes (not shown) such as, for example, a round hole and a long hole, are formed in the front end portion of the printing plate  12  by the punching section  16 . When processing at the punching section  16  has finished, the printing plate  12  is returned onto the feed guide  20 . 
     The exposure section  18  is equipped with a cylindrical rotary drum  24 . The rotary drum  24  is disposed to be parallel in a left-right direction, and rotatable in the directions of arrow A and arrow B shown in FIG.  1 . When the printing plate  12  has returned onto the feed guide  20  from the punching section  16  as described above, the conveyance guide unit  14  rotates and the feed guide  20  corresponds with the exposure section  18  (faces in a tangential direction of the rotary drum  24 ). Hence, the front end of the printing plate  12  is conveyed onto an outer periphery of the rotary drum  24 , and the printing plate  12  is positioned. 
     A plate-like front end chuck  26  is disposed at a position to which the front end of the printing plate  12  is conveyed on the outer periphery of the rotary drum  24 . A substantially central portion in a front-rear direction of the front end chuck  26  is supported such that the front end chuck  26  is freely rotatable at the rotary drum  24 , and is subjected to elastic force in a direction of separation of a front side of the front end chuck  26  from the outer periphery of the rotary drum  24 . 
     A mounting cam  28  is provided at an upper side of the front end chuck  26 . The mounting cam  28  applies pressure to the front side of the front end chuck  26 , and thus a rear side of the front end chuck  26  is separated from the outer periphery of the rotary drum  24 . In accordance therewith, the printing plate  12  that has been conveyed onto the outer periphery of the rotary drum  24  from the feed guide  20 , as described above, is inserted between the rear side of the front end chuck  26  and the outer periphery of the rotary drum  24 . In this state, positioning of the printing plate  12  is carried out. After the positioning of the printing plate  12  has been completed, the mounting cam  28  rotates and releases the pressure on the front side of the front end chuck  26 . As a result, the rear side of the front end chuck  26  is pressed against the front end of the printing plate  12  by the elastic force. Thus, the front end of the printing plate  12  is held to the outer periphery of the rotary drum  24 . When the front end of the printing plate  12  is thus held at the outer periphery of the rotary drum  24 , the rotary drum  24  is rotated in the direction of arrow A in FIG. 1, and the printing plate  12  is wound onto the outer periphery of the rotary drum  24 . 
     A squeeze roller  30  is disposed in a vicinity of the outer periphery of the rotary drum  24 , at a side of the mounting cam  28  in the direction of arrow A in FIG.  1 . The squeeze roller  30  is moved to the rotary drum  24  side thereof, and presses the printing plate  12  that is being wound onto the rotary drum  24  toward the rotary drum  24 , while rotating therewith. Thus, the printing plate  12  is closely adhered to the outer periphery of the rotary drum  24 . 
     A rear end chuck attachment/detachment unit  32  is disposed at the vicinity of the outer periphery of the rotary drum  24 , between the mounting cam  28  and the squeeze roller  30 . The rear end chuck attachment/detachment unit  32  includes a shaft  34 . The shaft  34  is moveable toward the rotary drum  24 . A rear end chuck  36  is mounted at a distal end of the shaft  34 . When a rear end of the printing plate  12  that is being wound onto the rotary drum  24  opposes the rear end chuck attachment/detachment unit  32 , the shaft  34  moves the rear end chuck  36  to the rotary drum  24  side thereof, and attaches the rear end chuck  36  at a predetermined position of the rotary drum  24 . At this time, the rear end chuck  36  is separated from the shaft  34 . Consequently, the rear end chuck  36  presses against the rear end of the printing plate  12 , and the rear end of the printing plate  12  is held to the outer periphery of the rotary drum  24 . 
     Accordingly, when the front end and the rear end of the printing plate  12  have been held to the rotary drum  24  by the front end chuck  26  and the rear end chuck  36 , the squeeze roller  30  is separated from the rotary drum  24 , and the rotary drum  24  is rapidly rotated at a predetermined rotation speed thereafter. 
     A recording head (exposure head)  38  is disposed at a rear side vicinity of the outer periphery of the rotary drum  24 . The recording head  38  is moveable along an axial direction (the left-right direction) of the rotary drum  24 . As shown in FIGS. 2 and 3, the recording head  38  is provided with a support platform  80 . A predetermined number of support rails  82  are fixed on the support platform  80  along the front-rear direction. An equipment platform  40  is disposed above the predetermined number of support rails  82 . A predetermined number of support guides  84  are fixed at a lower face of the equipment platform  40 . The support guides  84  fit onto the respective support rails  82 , and the support guides  84  slide relative to the support rails  82 . Thus, the equipment platform  40  is slideable in the front-rear direction. 
     A female screw plate  86 , which structures a focus adjustment component, is fixed on the equipment platform  40  at a substantially central portion in the front-rear direction of the equipment platform  40 , at a position which is offset leftward from a collimator lens  58  and a condensing lens  60 . An internal female thread (not shown) is formed along the front-rear direction in the female screw plate  86 . A male screw  88 , which also structures the focus adjustment component, is screwed into this internal thread. The male screw  88  serves as a driveshaft of a pulse motor  64  (focus adjustment correction device), which also structures the focus adjustment component. The pulse motor  64  passes through a through-hole  90 , which is formed in a front side region of the equipment platform  40 , and is fixed on the support platform  80 . When the male screw  88  is driven by the pulse motor  64  and rotated, the female screw plate  86  moves in the front-rear direction, and the equipment platform  40  slides in the front-rear direction. The pulse motor  64  is connected to a control device (not shown). A round column-shaped rotation cylinder  92  is fixed to the male screw  88 . When the rotation cylinder  92  is rotated manually and thus the male screw  88  is rotated, the female screw plate  86  is moved in the front-rear direction, and the equipment platform  40  can be slid in the front-rear direction. 
     A rail  42  along the front-rear direction is fixed on the equipment platform  40  at a rear end position of the equipment platform  40 . A moving stage  44  is disposed above the rail  42 . A predetermined number (two in the present embodiment) of sliding guides  46  are fixed at a lower face of the moving stage  44 . The respective sliding guides  46  fit onto the rail  42 , and the respective sliding guides  46  slide relative to the rail  42 . Thus, the moving stage  44  is slideable in the front-rear direction. 
     A female screw plate  48 , which structures an adjustment component, is fixed to a left side wall of the moving stage  44 . An internal thread (not shown) is formed along the front-rear direction in the female screw plate  48 . A male screw  50 , which also structures the adjustment component, is screwed into this internal thread. The male screw  50  serves as a driveshaft of a pulse motor  52 , which also structures the adjustment component. The pulse motor  52  is fixed on the equipment platform  40 . When the male screw  50  is driven by the pulse motor  52  and rotated, the female screw plate  48  moves in the front-rear direction, and the moving stage  44  slides in the front-rear direction. The pulse motor  52  is connected to the aforementioned control device. A round column-shaped rotation cylinder  54  is fixed to the male screw  50 . When the rotation cylinder  54  is rotated manually and thus the male screw  50  is rotated, the female screw plate  48  is moved in the front-rear direction, and the moving stage  44  can be slid in the front-rear direction. 
     A fiber array light source  56  is fixed on the moving stage  44  at a rear side region thereof. The fiber array light source  56  transmits a light beam, which is modulated on the basis of image data that has been read in, forward. The collimator lens  58 , which serves as a transmission component, is disposed on the moving stage  44  at a front side region thereof. The collimator lens  58  transmits the incident light beam from the fiber array light source  56  forward as predetermined parallel light or divergent light. 
     The condensing lens  60  is fixed on the equipment platform  40  at a front end portion thereof. The condensing lens  60  is disposed frontward of the collimator lens  58 . When the light beam transmitted from the collimator lens  58  is incident at the condensing lens  60 , the condensing lens  60  focuses the light beam and transmits the light beam forward. Thus, a high-power light beam (laser beam) is irradiated from the condensing lens  60  of the recording head  38  toward the rotary drum  24 , which is rotating at high-speed as mentioned above, contemporaneously with the rotation of the rotary drum  24 . Thus, the printing plate  12  is exposed on the basis of the image data (i.e., an image is recorded (drawn) on the printing plate  12 ). This exposure processing, of rotating the rotary drum  24  at high speed (mainscanning) while moving the recording head  38  in the axial direction of the rotary drum  24  (sub-scanning) is known as “scanning exposure”. 
     A temperature sensor  62 , which serves as a measuring component, is disposed on the equipment platform  40 , between the condensing lens  60  and the moving stage  44  (the collimator lens  58 ). The temperature sensor  62  measures, for example, the temperature of the equipment platform  40  between the condensing lens  60  and the collimator lens  58  (i.e., the recording head  38 ) before exposure processing of the printing plate  12 . The temperature sensor  62  is connected to the aforementioned control device. When the temperature sensor  62  measures the temperature of the equipment platform  40 , a required sliding amount (including a sliding direction) of the moving stage  44  is obtained from data which has been preparatorily stored as a table at the control device (this data concerns a relationship between temperature of the location at which the temperature sensor  62  is disposed and a separation between the condensing lens  60  and the collimator lens  58 ). The pulse motor  52  is driven on the basis of this sliding amount and direction, and slides the moving stage  44 . Thus, with this structure, the separation between the condensing lens  60  and the collimator lens  58  is always kept constant. 
     Further, when the temperature sensor  62  measures the temperature of the equipment platform  40 , a required sliding amount (including a sliding direction) of the moving stage  44  is obtained from data which has been preparatorily stored as a table at the control device (this data concerns a relationship between temperature of the location at which the temperature sensor  62  is disposed and an amount of divergence of the light beam from the collimator lens  58 ). The pulse motor  52  is driven on the basis of this sliding amount and direction, and slides the moving stage  44 . Thus, with this structure, the separation between the condensing lens  60  and the collimator lens  58  is adjusted, and undesired variation of the amount of divergence of the light beam that is incident on the condensing lens  60  from the collimator lens  58  is eliminated. 
     Further again, when the temperature sensor  62  measures the temperature of the equipment platform  40 , a required sliding amount (including a sliding direction) of the equipment platform  40  is obtained from data which has been preparatorily stored as a table at the control device (this data concerns a relationship between temperature of the location at which the temperature sensor  62  is disposed and a separation between the printing plate  12  that is wound onto the rotary drum  24  and the condensing lens  60 ). The pulse motor  64  is driven on the basis of this sliding amount and direction, and slides the equipment platform  40 . Thus, with this structure, the separation between the printing plate  12  wound onto the rotary drum  24  and the condensing lens  60  is always kept constant. 
     Yet further, when the temperature sensor  62  measures the temperature of the equipment platform  40 , a required sliding amount (including a sliding direction) of the equipment platform  40  is obtained from data which has been preparatorily stored as a table at the control device (this data concerns a relationship between temperature of the location at which the temperature sensor  62  is disposed and a focusing distance of the light beam from the condensing lens  60 ). The pulse motor  64  is driven on the basis of this sliding amount and direction, and slides the equipment platform  40 . Thus, with this structure, the separation between the printing plate  12  wound onto the rotary drum  24  and the condensing lens  60  is adjusted, and undesired variation of the focusing distance of the light beam from the condensing lens  60  is eliminated. 
     When the scanning exposure onto the printing plate  12  has been completed, the rotary drum  24  is temporarily halted at a position such that the rear end chuck  36  opposes the shaft  34 . The rear end chuck  36  is taken off from the rotary drum  24  by the shaft  34  (i.e., the rear end chuck  36  is mounted to the shaft  34 ), and pressure by the rear end chuck  36  on the rear end of the printing plate  12  is released. In addition, the conveyance guide unit  14  rotates and the discharge guide  22  corresponds with the exposure section  18  (faces in a tangential direction of the rotary drum  24 ). Then, the rotary drum  24  is rotated in the direction of arrow B in FIG. 1, and thus the printing plate  12  is conveyed rearward, from the rear end side thereof, and discharged to the discharge guide  22 . In accordance therewith, the mounting cam  28  is rotated, and applies pressure to the front end of the front end chuck  26 . Consequently, the pressure on the front end of the printing plate  12  from the rear end of the front end chuck  26  is released. Further, when the printing plate  12  has been transferred to the discharge guide  22 , the conveyance guide unit  14  rotates, and the printing plate  12  is ejected from the discharge guide  22 . 
     Next, operation of the present embodiment will be described. 
     In the printing plate automatic exposure device  10  having the structure described above, when the printing plate  12  is loaded at the feed guide  20 , firstly, the conveyance guide unit  14  is rotated and the feed guide  20  is corresponded with the punching section  16 . Hence, the front end portion of the printing plate  12  is conveyed into the punching section  16 . The predetermined number of punch holes are formed in the front end portion of the printing plate  12  that has been conveyed into the punching section  16 , and then the printing plate  12  is returned to the feed guide  20 . 
     Then, the conveyance guide unit  14  is rotated and the feed guide  20  is corresponded with the exposure section  18 . Hence, the printing plate  12  is conveyed to the exposure section  18  and positioned. The front end and rear end of the printing plate  12  that has been positioned are held to the outer periphery of the rotary drum  24  by the front end chuck  26  and the rear end chuck  36 , respectively. The printing plate  12  is closely adhered to the outer periphery of the rotary drum  24  by the squeeze roller  30  while the printing plate  12  is being wound onto the outer periphery of the rotary drum  24 . When the printing plate  12  has been wound onto the outer periphery of the rotary drum  24 , the rotary drum  24  is rotated at high speed, and in this state the recording head  38  irradiates a light beam from the fiber array light source  56 , through the collimator lens  58  and the condensing lens  60 . Thus, exposure processing is carried out. 
     When the exposure processing has been completed, the conveyance guide unit  14  is rotated and the discharge guide  22  is corresponded with the rotary drum  24 . Holding of the printing plate  12  to the outer periphery of the rotary drum  24  by the front end chuck  26  and the rear end chuck  36  is released, and the printing plate  12  is discharged from the rotary drum  24  to the discharge guide  22 . Thereafter, the conveyance guide unit  14  is rotated and the printing plate  12  is ejected from the discharge guide  22 . 
     In this operation, the temperature sensor  62  disposed at the recording head  38  measures the temperature of the recording head  38  (i.e., the temperature of the equipment platform  40  between the condensing lens  60  and the moving stage  44 ). The pulse motor  52  is driven on the basis of the measured temperature of the recording head  38 , and thus the separation between the collimator lens  58  and the condensing lens  60  is adjusted. As a result, the separation between the collimator lens  58  and the condensing lens  60  can be kept constant, regardless of contraction or expansion of the recording head  38  due to temperature variations of the recording head  38 . In addition, even if the temperature of the collimator lens  58  changes due to a change in temperature of the recording head  38 , such that the collimator lens  58  expands or contracts and thus the amount of divergence of the light beam from the collimator lens  58  is altered, the pulse motor  52  can adjust the separation between the collimator lens  58  and the condensing lens  60 , and this alteration of the amount of divergence of the light beam incident on the condensing lens  60  from the collimator lens  58  can be eliminated. 
     Accordingly, even when the light beam incident on the condensing lens  60  from the collimator lens  58  is divergent, shifts in the magnification of the image to be recorded can be prevented regardless of temperature variations of the recording head  38  (without controlling the temperature of the recording head  38  (the collimator lens  58 )). 
     Moreover, when the temperature sensor  62  measures the temperature of the recording head  38 , the pulse motor  64  is driven on the basis of the measured temperature of the recording head  38 , and thus the separation between the condensing lens  60  and the printing plate  12  wound onto the rotary drum  24  is adjusted. As a result, even if, when the recording head  38  expands or contracts due to temperature variations of the recording head  38 , such that the separation between the recording head  38  and the printing plate  12  changes and hence the separation between the condensing lens  60  and the printing plate  12  changes, the separation between the condensing lens  60  and the printing plate  12  can be kept constant by driving the pulse motor  64 . In addition, even if the temperature of the condensing lens  60  changes due to a change in temperature of the recording head  38 , such that the condensing lens  60  expands or contracts and thus the focusing distance of the light beam from the condensing lens  60  is altered, the separation between the condensing lens  60  and the printing plate  12  is adjusted by driving the pulse motor  64 , and this alteration of the focusing distance of the light beam from the condensing lens  60  can be eliminated. 
     Accordingly, even when the temperature of the recording head  38  changes, a shift of focus (zoom) of the image to be recorded can be prevented without controlling the temperature of the recording head  38  (the condensing lens  60 ). 
     Furthermore, (a portion of) the equipment platform  40  between the condensing lens  60  and the moving stage  44  is a location that highly effects the separation between the condensing lens  60  and the collimator lens  58 , the separation between the condensing lens  60  and the printing plate  12  wound onto the rotary drum  24 , and the temperatures of the collimator lens  58  and the condensing lens  60  when temperature thereof changing. Accordingly, because the temperature sensor  62  measures the temperature of the equipment platform  40  between the condensing lens  60  and the moving stage  44 , variations (change) in the separation between the collimator lens  58  and the condensing lens  60 , variations in the separation between the condensing lens  60  and the printing plate  12 , and variations in the temperatures of the collimator lens  58  and the condensing lens  60  can be favorably detected. Therefore, the separation between the collimator lens  58  and the condensing lens  60  and the separation between the condensing lens  60  and the printing plate  12  wound onto the rotary drum  24  can be favorably adjusted. 
     Because the separation between the collimator lens  58  and the condensing lens  60  can be adjusted by the pulse motor  52 , a requirement for consideration of accuracy of the separation between the collimator lens  58  and the condensing lens  60  in the front-rear direction (the direction of irradiation of the beam) when the collimator lens  58  (the moving stage  44 ) and the condensing lens  60  are assembled can be relaxed. 
     Further, because the separation between the condensing lens  60  and the rotary drum  24  can be adjusted by the pulse motor  64 , a requirement for consideration of accuracy of the separation between the condensing lens  60  and the rotary drum  24  in the front-rear direction (the direction of irradiation of the beam) when the condensing lens  60  and the rotary drum  24  are assembled can be relaxed. 
     In the structure of the present embodiment, the moving stage  44  is slid by driving of the pulse motor  52 , and thus the separation between the collimator lens  58  and the condensing lens  60  is adjusted. The structure shown in FIG. 4 is also acceptable. Specifically, in the structure shown in FIG. 4, a pair of leaf springs  70 , which are resilient, are standingly provided. The pair of leaf springs  70  face one another in the front-rear direction. The moving stage  44  bridges across between upper portions of the pair of leaf springs  70 . Thus, the moving stage  44  can be moved in the front-rear direction by resilient deformation of the pair of leaf springs  70 . A cam  72 , which is an eccentric cam or the like structuring the adjustment component, is provided rearward of the pair of leaf springs  70 . The cam  72  is connected to a driving motor (not shown), which also structures the adjustment component, and the cam  72  is driven to rotate by the driving motor. This driving motor is connected to the aforementioned control device. 
     In this structure, the driving motor is driven on the basis of the temperature of the recording head  38  measured by the temperature sensor  62 . Thus, the cam  72  is rotated and the pair of leaf springs  70  is resiliently deformed. Consequently, the moving stage  44  is moved in the front-rear direction, and the separation between the collimator lens  58  and the condensing lens  60  is adjusted. 
     Furthermore, in the structure of the present embodiment, the equipment platform  40  is slid by driving of the pulse motor  64 , and thus the separation between the condensing lens  60  and the rotary drum  24  (the printing plate  12 ) is adjusted. However, the structure shown in FIG. 4 is also acceptable. Specifically, the equipment platform  40  bridges across between a pair of resilient leaf springs which are standingly provided on the support platform  80 . A cam, which is an eccentric cam or the like structuring the focus adjustment component, is rotated on the basis of the temperature of the recording head  38 , as measured by the temperature sensor  62 , and resiliently deforms the pair of leaf springs. Thus, the equipment platform  40  is moved in the front-rear direction, and the separation between the condensing lens  60  and the rotary drum  24  is adjusted. 
     Further again, in the structure of the present embodiment, the temperature sensor  62  is disposed at the recording head  38 , and measures the temperature of the recording head  38  (the temperature of the equipment platform  40  between the condensing lens  60  and the moving stage  44 ). However, a temperature sensor (measuring component) may be disposed at a location which is presumed to be associated with the temperature of the recording head, so as to measure the temperature of that location. (Temperature of that location corresponds to temperature of the recording head such that the temperature of the recording head can be estimated on the basis of the temperature of that location.) For example, as shown in FIG. 5, a structure in which the temperature sensor  62  is disposed in a vicinity above the equipment platform  40  between the condensing lens  60  and the moving stage  44 , and the temperature sensor  62  measures the temperature of that position (the temperature of the atmosphere in the vicinity of the recording head  38 ) is also acceptable. 
     Further, the present invention is not limited to the same. It is also preferable that a plurality of temperature sensors are disposed at respective predetermined positions, and data concerns a relationship between temperatures of the respective positions and the separation between the condensing lens  60  and the collimator lens  58 , the amount of divergence of the light beam from the collimator lens  58 , the separation between the printing plate  12  that is wound onto the rotary drum  24  and the condensing lens  60 , and the focusing distance of the light beam from the condensing lens  60 , is preparatorily stored as a table at the control device. Then, the above described adjustment (control) is carried out on the basis of this data and the measured temperatures. 
     The present embodiment is structured for application of the present invention to CTP printing, but the present invention may be applied to other image-recording devices provided with zoom mechanisms. 
     In an image-recording device according to one aspect of the present invention, a measuring component measures the temperature of a recording head and/or the temperature of a location which is presumed to be associated with the temperature of the recording head. On the basis of the measured temperature, an adjustment component adjusts a separation between a transmission component and a focusing lens. As a result, the separation between the transmission component and the focusing lens can be kept constant by the adjustment component. In addition, the adjustment component can adjust the separation between the transmission component and the focusing lens so as to eliminate an error in an amount of divergence of a light beam that is incident on the focusing lens from the transmission component. Accordingly, even when the light beam incident on the focusing lens from the transmission component is divergent, an error in magnification of an image that is recorded can be prevented, regardless of temperature variations of the recording head. 
     In an image-recording device according to another aspect of the present invention, a measuring component measures the temperature of a recording head and/or the temperature of a location which is presumed to be associated with the temperature of the recording head. On the basis of the measured temperature, a focus adjustment component adjusts a separation between a focusing lens and a printing plate. As a result, the separation between the focusing lens and the printing plate can be kept constant by the focus adjustment component. In addition, the focus adjustment component can adjust the separation between the focusing lens and the printing plate so as to eliminate an error in a focusing distance of a light beam from the focusing lens. Accordingly, an error in focusing of an image that is recorded can be prevented, regardless of temperature variations of the recording head.