Abstract:
An image forming device provided with: a recording head that renders an image by ejecting liquid droplets onto a recording medium; an attraction image rendering section having a liquid droplet reception flat portion disposed facing the recording head, the attraction image rendering section attracting the recording medium onto the flat portion and maintaining the flatness of the recording medium; an upstream side conveying section that feeds the recording medium out toward the attraction image rendering section; and a reverse-feed-prevented conveying roller disposed at the downstream side of the attraction image rendering section, the reverse-feed-prevented conveying roller being capable of friction-pushed rotation toward the conveying direction downstream side, nipping the recording medium and feeding the recording medium toward the conveying direction downstream side, and prevented from rotation toward the conveying direction upstream side.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority under 35 USC 119 from Japanese Patent Application No. 2009-069986 filed on Mar. 23, 2009, the disclosure of which is incorporated by reference herein. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Technical Field 
         [0003]    The present invention relates to an image forming device, and in particular to an image forming device that forms an image on a recording medium by ejecting a liquid onto the recording medium. 
         [0004]    2. Related Art 
         [0005]    Image forming devices that form images on recording media by ejection of a liquid, such as ink, are widely known. In such image forming devices, the recording medium is conveyed to directly below a recording head, and an image is rendered. 
         [0006]    In such image forming devices, since any non-uniformity in the separation distance between the recording head and the recording medium has an effect on image rendering, correction to maintain the recording medium in a flat shape is already sometimes performed. 
         [0007]    For example, in Japanese Utility Model Application Laid-Open No. 01-44149, the feeding speed of recording medium further to the downstream side of a recording section is made faster than to the upstream side thereof, and by slippage of the drive shaft at the downstream side using a torque limiter, a back tension is applied to the recording medium in the recording section, ensuring the flatness of the recording medium. However, there are problems with such a method in that generation of longitudinal creases sometimes occurs due to tensioning the recording medium, and slippage of the drive shaft sometimes occurs due to influence from the conveying direction downstream side. 
         [0008]    Also, in Japanese Patent Application Laid-Open (JP-A) No. 2006-56655, flatness in a recording section is ensured by employing suction generation means, and by provision of a loop shaped section between the recording section and a cutter section, influence from the loop shaped section is suppressed, thereby suppressing flapping of the recording medium at the upstream side of the plural roller loop shaped section. However, in the technology of Japanese Patent Application Laid-Open (JP-A) No. 2006-56655, since there is a strong gripping force employed at the downstream side of the recording section, slackness of the recording medium in the recording section readily develops when the feed speed at the upstream side is fast. In addition, when the speed at the downstream side is fast, slippage is sometimes generated relative to the image face of the recording medium, this being a cause of image quality deterioration. Also, since plural rollers are also required, this increases the number of components. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention is made in consideration of the above circumstances, and addresses the issue of provision of an image forming device capable of ensuring a high precision of flatness of a recording medium in a recording section. 
         [0010]    An image forming device of a first aspect includes: a recording head that renders an image by ejecting liquid droplets onto a recording medium; an attraction image rendering section having a liquid droplet reception flat portion disposed facing the recording head, the attraction image rendering section attracting the recording medium onto the flat portion and maintaining the flatness of the recording medium; an upstream side conveying section that feeds the recording medium out toward the attraction image rendering section; and a reverse-feed-prevented conveying roller disposed at the downstream side of the attraction image rendering section, the reverse-feed-prevented conveying roller being capable of friction-pushed rotation toward the conveying direction downstream side, nipping the recording medium and feeding the recording medium toward the conveying direction downstream side, and prevented from rotation toward the conveying direction upstream side. 
         [0011]    In the image forming device configured as described above, image rendering (recording) is performed to the recording medium on the flat portion of the attraction image rendering section. The flatness of the recording medium on the flat portion is maintained by attracting the recording medium onto the flat portion. The reverse-feed-prevented conveying roller that is disposed at the downstream side of the attraction image rendering section, nips the recording medium and is capable of pushed rotation toward the conveying direction downstream side due to friction against the recording medium (friction-pushed rotation). Consequently, the recording medium can be conveyed between the upstream side conveying section and the reverse-feed-prevented conveying roller at the feed speed of the upstream side conveying section. In addition, the reverse-feed-prevented conveying roller is prevented from rotation toward the conveying direction upstream side, therefore influence to the upstream side, due to slackness in the recording medium at the downstream side of the reverse-feed-prevented conveying roller or the like, can be suppressed. 
         [0012]    In an image forming device of a second aspect, the reverse-feed-prevented conveying roller is capable of being rotationally driven toward the conveying direction downstream side at a conveyance speed that is the same as, or less than, a conveyance speed of the upstream side conveying section. 
         [0013]    The reverse-feed-prevented conveying roller conveys the recording medium by friction-pushed rotation with the feed speed of the upstream side conveying section, however on occasions such as when the downstream side edge of the recording medium has passed through the upstream side conveying section or the like, driving force for conveying the recording medium is required. In order to address this, by the reverse-feed-prevented conveying roller being capable of being rotationally driven in this manner toward the conveying direction downstream side at a conveyance speed that is the same as, or less than, a conveyance speed of the upstream side conveying section, the recording medium can be conveyed while ensuring the flatness thereof. 
         [0014]    In an image forming device of a third aspect, the reverse-feed-prevented conveying roller nips the recording medium against the top face of the flat portion. 
         [0015]    According to the above configuration, buckling of the recording medium can be suppressed, since there is no separation between the flat portion and the reverse-feed-prevented conveying roller. 
         [0016]    In an image forming device of a fourth aspect, the relationship S&lt;2π(E×I/F) 1/2  is satisfied, wherein: S is a separation distance between the downstream end of the flat portion and a nip portion of the recording medium at the reverse-feed-prevented conveying roller; F is the friction-pushed load on the reverse-feed-prevented conveying roller; E is the Young&#39;s modulus of the recording medium; and I is the area moment of inertia of the recording medium. 
         [0017]    By setting in this manner, buckling of the recording medium between the flat portion and the reverse-feed-prevented conveying roller can be suppressed. 
         [0018]    In an image forming device of a fifth aspect, the recording medium is fed out from a wound state of a roll shape toward the flat portion with an unwind direction having the convex face of the recording medium facing toward the recording head in the attraction image rendering section. 
         [0019]    By setting any curl due to winding in the recording medium in the direction described above, the flatness can be more effectively ensured by attraction toward the flat portion in the attraction image rendering section, in comparison to cases disposed in the opposite direction. 
         [0020]    An image forming device of a sixth aspect, further includes: second conveying rollers that are provided at the conveying direction downstream side of the reverse-feed-prevented conveying roller, and that nip the recording medium and convey the recording medium toward the downstream side; a cutter section that cuts the recording medium to a specific size; and a curved conveying section that is provided between the reverse-feed-prevented conveying roller and the second conveying rollers and that bends the recording medium and accommodates any difference in conveying amounts between the reverse-feed-prevented conveying roller and the second conveying rollers due to conveyance being stopped in the cutter section when the recording medium is being cut. 
         [0021]    When a curved conveying section is provided in this manner so as to accommodate any difference in conveying amount of the recording medium when conveying is stopped during cutting by a cutter section disposed at the downstream side of the attraction image rendering section, the reverse-feed-prevented conveying roller is preferably employed since external force readily acts on the recording medium on the attraction image rendering section due to influence from the curved conveying section. 
         [0022]    In an image forming device of a seventh aspect, the direction of curvature of the recording medium in the curved conveying section is the same direction as the winding direction of the recording medium. 
         [0023]    By setting the direction of curvature of the recording medium in this manner, the reaction force of the recording medium in the curved conveying section is smaller than would be the case were the opposite direction to be adopted, and influence on the reverse-feed-prevented conveying roller can be decreased. 
         [0024]    In an image forming device of an eighth aspect the direction of curvature of the recording medium in the entire region between the reverse-feed-prevented conveying roller and the second conveying rollers is the same as the winding direction of the recording medium. 
         [0025]    By setting the direction of curvature of the recording medium as above, the reaction force of the recording medium between the reverse-feed-prevented conveying roller and the second conveying rollers can be made even smaller, and influence on the reverse-feed-prevented conveying roller can be decreased. 
         [0026]    According to the present invention a high precision of flatness of a recording medium in a recording section can be ensured. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]    Exemplary embodiments of the present invention will be described in detail based on the following figures, wherein: 
           [0028]      FIG. 1  is a schematic configuration diagram showing an image forming device according to a first exemplary embodiment; 
           [0029]      FIG. 2  is a perspective view showing a configuration of an image forming device according to the first exemplary embodiment in the vicinity of an attraction image rendering section; 
           [0030]      FIG. 3  is a schematic configuration diagram of an image forming device according to an exemplary modification of the first exemplary embodiment; 
           [0031]      FIG. 4  is a schematic configuration diagram of an image forming device according to another exemplary modification of the first exemplary embodiment; 
           [0032]      FIG. 5  is a schematic configuration diagram of an image forming device according to another exemplary modification of the first exemplary embodiment; 
           [0033]      FIG. 6  is a schematic configuration diagram of an image forming device according to another exemplary modification of the first exemplary embodiment; 
           [0034]      FIG. 7  is a side view of a schematic configuration diagram of an image forming device according to a second exemplary embodiment; 
           [0035]      FIG. 8  is a perspective view showing a conveyor belt of an image forming device according to the second exemplary embodiment; and 
           [0036]      FIG. 9  is a side view of a schematic configuration diagram of an image forming device according to an exemplary modification of the second exemplary embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     First Exemplary Embodiment 
       [0037]    Explanation will now be given of an exemplary embodiment of the present invention, with reference to the drawings. 
         [0038]    As shown in  FIG. 1 , an image forming device  10  according to the present exemplary embodiment is equipped with: a roll-paper feed section  12 ; a slow-scan roller  14 ; a recording head  16 ; an attraction image rendering section  18 ; first conveying rollers  20 ; second conveying roller  34 ; a cutter  36 ; a curved conveying section  30 ; discharge rollers  38 ; and a paper discharge tray  39 . 
         [0039]    The roll-paper feed section  12  is stocked, as a recording medium, with elongated recording paper SH wound into a roll shape to form a roll recording paper (continuous paper) SR. Examples of the recording paper SH include ordinary paper, inkjet recording paper that has an ink absorbing layer on both faces thereof, and the like. The roll recording paper SR is unwound toward the conveying direction downstream side, by a conveying roller  13  or the like, and is conveyed out as a web (in an uncut elongated shape). It should be noted that while in the present exemplary embodiment explanation is given of image rendering on roll recording paper, an image forming device additionally provided with a cassette stacked with cut sheets of paper and capable of also rendering images on cut sheets may also be used. 
         [0040]    The recording head  16 , as shown in  FIG. 2 , is mounted to guide shafts  11 , and is capable of moving along the guide shafts  11  in the width direction of the recording paper SH (this direction is referred to below as “fast-scanning direction X”). Nozzles (not shown in the figures) that eject ink are configured on the bottom face of the recording head  16 , and an image is formed on the recording paper SH by ink being ejected from the nozzles in accordance with image data. 
         [0041]    As shown in  FIG. 1 , the attraction image rendering section  18  is disposed below the bottom face of the recording head  16  and facing the recording head  16 . The attraction image rendering section  18  includes a flat portion  17  formed at the top face thereof, and suction fans  19  housed therein. 
         [0042]    The top face of the flat portion  17  is formed in a flat shape that is disposed so as to face the recording head  16  and be parallel thereto. The flat portion  17  is configured with plural small holes  17 A passing through to the inside of the attraction image rendering section  18 . The suction fans  19  draw in air so as to form a negative pressure within the attraction image rendering section  18 . The recording paper SH on the attraction image rendering section  18  is thereby attracted onto the flat portion  17  by air being drawn in through the small holes  17 A, and flatness is maintained. Ink is ejected toward the recording paper SH on the flat portion  17  and an image is formed. 
         [0043]    The slow-scan roller  14  is disposed at the conveying direction upstream side of the attraction image rendering section  18 . A pulley  44  is attached at one end of a rotation shaft  14 A of the slow-scan roller  14 . The pulley  44  is connected to a motor shaft  46 A of a motor  46  via a belt  45 , transmitting driving force of the motor  46  to the slow-scan roller  14 . 
         [0044]    Presser rollers  40  are disposed at the outer peripheral face of the slow-scan roller  14 . The recording paper SH is nipped by the slow-scan roller  14  against the presser rollers  40  and fed toward the attraction image rendering section  18 . The recording paper SH is fed out to the conveying direction downstream side such that the outside face of the recording paper SH, when wound in a roll shape, faces toward the recording head  16 . The feeding out direction will be referred to below as “slow-scan direction Y”. Rendering of images onto the recording paper SH is performed, based on image data, by scanning the recording head  16  in the fast-scanning direction X, and by repeatedly feeding out the recording paper SH in the slow-scan direction Y. The conveyance speed of the recording paper SH at the slow-scan roller  14  is referred to as V 0 . 
         [0045]    An encoder  42  is attached to the other end of the rotation shaft  14 A of the slow-scan roller  14 . The encoder  42  feeds back to the motor  46  the amount by which the recording paper SH has been fed by the slow-scan roller  14 . Driving of the motor  46  is controlled based on the feed amount data from the encoder  42 , and the recording paper SH is intermittently fed in the slow-scan direction Y. 
         [0046]    Note that, as a method for raising the precision of feeding the recording paper SH, a high resolution encoder may be employed as the encoder, and, by identifying outer diameters and deflection data for the slow-scan roller  14  in advance, the feed amount due to the rotation angle of the slow-scan roller  14  may be corrected. 
         [0047]    The first conveying rollers  20  are disposed at the downstream side of the attraction image rendering section  18 . The first conveying rollers  20  are configured from a pair of first rollers  20 A,  20 B. A gear  22  is attached to one end of a rotation shaft  20 S of the first roller  20 A, and driving force of a motor  26  is transmitted to the first roller  20 A through gears  22 ,  24 . The gear  22  is attached to the rotation shaft  20 S through a one-way clutch  21 . Due to the one-way clutch  21 , the rotation shaft  20 S performs slipping rotation with respect to the gear  22  when a specific rotation load toward the conveying direction downstream side is applied. Consequently, the first conveying rollers  20  are capable of friction-pushed rotation in the conveying direction downstream side when a specific friction-pushed load is applied. Rotation of the rotation shaft  20 S toward the conveying direction upstream side is prevented by the one-way clutch  21 . 
         [0048]    The relationship of Equation 1 below is satisfied, wherein: S is the separation distance between the downstream end of the flat portion  17  of the attraction image rendering section  18  and the nip portion of the recording paper SH in the first conveying rollers  20 ; E is the Young&#39;s modulus of the recording paper SH; I is the area moment of inertia of the recording paper SH; and F is the friction-pushed rotational load on the first conveying rollers  20  toward the conveying direction downstream side. 
         [0000]        S&lt; 2π( E×I/F ) 1/2   (Equation 1)
 
         [0049]    By satisfying Equation 1 above, bucking of the recording paper SH between the downstream end of the flat portion  17  of the attraction image rendering section  18  and the first conveying rollers  20  can be prevented. 
         [0050]    The recording paper SH is nipped between the first roller  20 A and the first roller  20 B and fed toward the conveying direction downstream side. The conveyance speed due to driving the first conveying rollers  20  by the motor  26  is designated V 1 . Conveyance speed V 1  is the same as, or less than, the conveyance speed V 0  at the slow-scan roller  14  (V 1 ≦V 0 ). 
         [0051]    The curved conveying section  30  is provided at the downstream side of the first conveying rollers  20 . A moveable guide  32  is provided in the curved conveying section  30 . The moveable guide  32  is curved in a U-shape from the first conveying rollers  20  to second conveying rollers  34 , described below. The moveable guide  32  is capable of swinging, about an end shaft  32 A on the first conveying rollers  20  side of the moveable guide  32 , between a guide position P 1  and an open position P 2 . In the curved conveying section  30 , the recording paper SH is conveyed in a U-shape in order to absorb any difference in conveying amount at the first conveying rollers  20  and the conveying amount at the second conveying rollers  34 . The direction of curve of the bottom of the U-shape is the opposite direction to the wind direction of the roll recording paper SR (the opposite direction to any curl that has been formed in the recording paper SH). 
         [0052]    The second conveying rollers  34  are disposed at the downstream side end of the curved conveying section  30 , nipping the recording paper SH between a pair of second rollers  34 A,  34 B. The second conveying rollers  34  are connected to a non-illustrated motor and the recording paper SH is conveyed by rotation toward the downstream side. 
         [0053]    The cutter  36  is provided at the downstream side of the second conveying rollers  34 . The recording paper SH is cut into a specific size by the cutter  36 . 
         [0054]    The discharge rollers  38  are disposed at the downstream side of the cutter  36 , and the paper discharge tray  39  is disposed at the downstream side of the discharge rollers  38 . The recording paper SH is discharged into the paper discharge tray  39  by the discharge rollers  38 . 
         [0055]    In the image forming device  10  configured as above, conveying of the recording paper SH and image rendering on the recording paper SH are performed as described below. 
         [0056]    The recording paper SH is unwound and fed from the roll-paper feed section  12  toward the conveying direction downstream side by the conveying roller  13  or the like, and fed toward the slow-scan roller  14 . The recording paper SH is fed out toward the attraction image rendering section  18 , while being pressed to the outer periphery of the slow-scan roller  14  by the presser rollers  40 . In the attraction image rendering section  18  the recording paper SH is conveyed out in the slow-scan direction Y, while the recording paper SH is attracted onto the top face of the flat portion  17  by the negative pressure due to the suction fans  19 . 
         [0057]    In the attraction image rendering section  18 , image rendering on the recording paper SH is performed, based on image data, by repeatedly scanning the recording head  16  in the fast-scanning direction X and feeding the recording paper SH out in the slow-scan direction Y, using the slow-scan roller  14 . 
         [0058]    The recording paper SH is nipped in the first conveying rollers  20  at the downstream side of the attraction image rendering section  18 . When this occurs, since the conveyance speed V 1  of the first conveying rollers  20  is the same as, or less than, the conveyance speed V 0  of the slow-scan roller  14 , the first conveying rollers  20  are usually friction-pushed rotated toward the conveying direction downstream side, rotated friction-pushed load from the recording paper SH toward the downstream side, and the recording paper SH is fed out at a conveyance speed V 0 . Due to the recording paper SH being conveyed in this manner by the friction-pushed rotation of the first conveying rollers  20 , generation of longitudinal creases, due to pulling recording paper toward the conveying direction downstream side, can be suppressed. Note that after the trailing edge of the recording paper SH has passed the slow-scan roller  14  the recording paper SH is conveyed by driving the first conveying rollers  20 . 
         [0059]    After passing the first conveying rollers  20 , the recording paper SH is conveyed along a U-shaped conveying path and nipped in the second conveying rollers  34 . Up until the leading edge of the recording paper SH is nipped by the second conveying rollers  34 , the moveable guide  32  is positioned in the guide position P 1 , guiding the leading edge of the recording paper SH into the second conveying rollers  34 . After the leading edge of the recording paper SH has been nipped by the second conveying rollers  34 , the moveable guide  32  is moved to the open position P 2 , and a degree of freedom is added to the conveying amount of the recording paper SH. 
         [0060]    The recording paper SH is fed out toward the cutter  36  by the second conveying rollers  34 . The second conveying rollers  34  stop conveying the recording paper SH when the recording paper SH is being cut in the cutter  36 , and the second conveying rollers  34  convey the recording paper SH when not cutting. When the second conveying rollers  34  are stopped, the length of the recording paper SH in the curved conveying section  30  gets longer, since the conveying amount at the first conveying rollers  20  is greater than the conveying amount at the second conveying rollers  34 . This extra length of the recording paper SH is accommodated in the curved conveying section  30 . 
         [0061]    When this occurs, the recording paper SH curved in the curved conveying section  30  acts to apply external force to the first conveying rollers  20  in the opposite direction to the conveying direction, however the first conveying rollers  20  are prevented from rotating in the opposite direction to the conveying direction by the one-way clutch  21 . Consequently, the recording paper SH is not reverse-conveyed toward the attraction image rendering section  18  side, external force from the curved conveying section  30  is blocked, and good image rendering can be performed in the attraction image rendering section  18 . 
         [0062]    The recording paper SH that has been cut in the cutter  36  is discharged into the paper discharge tray  39  by the discharge rollers  38 . 
         [0063]    As explained above, according to the present exemplary embodiment, since the first conveying rollers  20  feed out the recording paper SH by friction-pushed rotation due to load from the recording paper SH fed out from the slow-scan roller  14 , generation of longitudinal creases, due to action of tension on the recording paper SH toward the conveying direction downstream side, can be suppressed. Since the first conveying rollers  20  are prevented from rotating in the opposite direction to the conveying direction, there is no influence of external force from the curved conveying section  30  to the attraction image rendering section  18 , and good image rendering can be performed on the recording paper SH. 
         [0064]    It should be noted that while in the present exemplary embodiment the direction of curvature of the recording paper SH in the U-shaped bottom portion of the curved conveying section  30  is the opposite direction to the winding direction of the roll recording paper SR, the direction of curvature may be the same direction as the winding direction of the roll recording paper SR, as shown in  FIG. 3 . By making the direction of curvature the same as the winding direction of the roll recording paper SR in this manner, external force on the first conveying rollers  20  due to curvature can be suppressed. 
         [0065]    In addition, as shown in  FIG. 4 , the conveying path may be configured such that the direction of curvature of the recording paper SH is the same direction to the winding direction of the roll recording paper SR for the whole region, namely the whole of the conveying path in the section from the nip portion of the recording paper SH in the first conveying rollers  20  to the nip portion of the recording paper SH in the second conveying rollers  34 , not just the direction of curvature of the U-shaped bottom portion of the recording paper SH. In this manner, due to there being no portions in which the direction of curvature of the recording paper SH is the opposite direction to the winding direction of the roll recording paper SR, the application of external force to the first conveying rollers  20  due to winding curl can be effectively suppressed. 
         [0066]    Also, while in the present exemplary embodiment the first conveying rollers  20  are disposed further to the downstream side than the attraction image rendering section  18 , the first roller  20 A alone may be disposed above the flat portion  17  at the attraction image rendering section  18  side, as shown in  FIG. 5 . In such cases, the recording paper SH is nipped between the first roller  20 A and the flat portion  17 . 
         [0067]    Furthermore, while explanation has been given in the present exemplary embodiment of an example where suctioning in the attraction image rendering section  18  is performed by suction fans  19 , a suction pump  19 P may be employed for suctioning, as shown in  FIG. 6 . In such cases, the suction pump  19 P is connected to the attraction image rendering section  18 , and the recording paper SH is attracted onto the flat portion  17  by negative pressure within the attraction image rendering section  18  due to the suction pump  19 P, and the flatness of the recording paper SH in the attraction image rendering section  18  can be secured. 
       Second Exemplary Embodiment 
       [0068]    Explanation will now be given of a second exemplary embodiment of the present invention. The present exemplary embodiment is provided with an attraction image rendering section  50  in place of the attraction image rendering section  18  of the first exemplary embodiment. Since other parts of the configuration are similar to that of the first exemplary embodiment, the same reference numerals will be allocated thereto, and detailed explanation thereof omitted. 
         [0069]    As shown in  FIG. 7 , the attraction image rendering section  50  of the present exemplary embodiment is equipped with a conveyer belt  52  and suction fans  19 . The conveyer belt  52  is of an endless shape and is configured over the entire surface thereof with plural suction holes  52 A for suctioning, as shown in  FIG. 8 . The conveyer belt  52  is entrained around belt rollers  54 ,  56 . The belt roller  56  is disposed at the conveying direction downstream side and is rotationally driven by a non-illustrated motor so as to convey the recording paper SH toward the conveying direction downstream side. The belt roller  54  is capable of friction-pushed rotation. The conveyance speed V 2  due to the belt roller  56  is the same as, or greater than, the conveyance speed V 0  due to the slow-scan roller  14  (V 2 ≧V 0 ≧V 1 ). 
         [0070]    The suction fans  19  are disposed between the two sides of the conveyer belt  52 . The suction fans  19  suction air such that there is a negative pressure at the top side portion of the attraction image rendering section  50 . The recording paper SH on the attraction image rendering section  50  is thereby attracted onto the conveyer belt  52  from suctioning of the suction holes  52 A and the flatness of the recording paper SH is maintained. 
         [0071]    According to the present exemplary embodiment, in a similar manner to that in the first exemplary embodiment, generation of longitudinal creases, due to action of tensional force on the recording paper SH toward the downstream side, can be suppressed. In addition, since the first conveying rollers  20  are prevented from rotating in the opposite direction to the conveying direction, there is no influence of external force from the curved conveying section  30  acting on the attraction image rendering section  50 , and good image rendering can be performed on the recording paper SH. 
         [0072]    Note that while the present exemplary embodiment employs the conveyer belt  52  configured with the suction holes  52 A and the suction fans  19 , when the thickness of the recording paper SH is comparatively thin, then in place of these components an electrically charged belt  62  without suction holes and a charging roller  64  may be employed, as shown in  FIG. 9 , and the recording paper SH attracted by electrostatic attraction. 
         [0073]    While the present invention has been explained by way of the exemplary embodiments described above, these are only exemplary embodiments, and various variations and modifications may be made within a scope not departing from the spirit of the present invention. The scope of the present invention is not limited by these exemplary embodiments.