Patent Publication Number: US-7722182-B2

Title: Inkjet recording device and driving unit provided therein

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application claims priorities from Japanese Patent Applications No. 2005-375952 filed on Dec. 27, 2005 and No. 2005-379602 filed on Dec. 28, 2005. The entire content of each of these priority applications is incorporated herein by reference. 
   TECHNICAL FIELD 
   The disclosure relates to an inkjet-recording device and components employed in this device, and particularly to the structure of a component functioning to drive a movable support piece provided on a platen. 
   BACKGROUND 
   An inkjet-recording device includes a recording head with a plurality of juxtaposed nozzles. A recording paper is conveyed below the recording head while the recording head forms an image on the paper. The recording head records an image on the recording paper by moving in a main scanning direction (orthogonal to the paper-conveying direction), while ejecting ink droplets from the nozzles at a prescribed timing. In recent years, inkjet-recording devices have been provided with a photo printing function. This type of image recording is called “borderless recording” because the image is recorded without leaving margins on the edges of the recording paper. 
   In borderless recording, the recording head is moved beyond the edges of the paper and ink is ejected to a point outside the region occupied by the recording paper. For example, in Japanese unexamined patent application publication No. 2000-118058, when borderless recording is performed on the leading and trailing edges of the recording paper, the recording paper is positioned relative to the recording head so that a portion of the nozzles in the recording head is positioned off the edge of the recording paper. Consequently, the recording head ejects ink droplets through these nozzles onto a platen provided below the recording paper. The platen is provided with a groove formed in the top portion thereof and extending in the main scanning direction, and an ink absorbing material disposed inside this groove for absorbing the ink droplets. This configuration makes it possible to record an image over the entire recording paper, without leaving a border along the edges of the recording paper, while preventing ink ejected onto the platen from staining the underside of the recording paper. 
   There has also been a demand in recent years for inkjet-recording devices capable of recording images at a faster rate. Conventional attempts to increase the image recording speed have involved increasing the size of the recording head in order to increase the number of nozzles arranged in the paper-conveying direction. However, in order to perform high-quality borderless recording, it has been necessary to increase the width (dimension in the paper-conveying direction) of the groove provided in the platen as the size of the recording head is increased. 
   However, since the recording paper is positioned above this groove when performing borderless recording, an increased groove width may cause the recording paper to deform, bending downward into the groove. Such bending of the recording paper changes the distances between nozzles in the recording head and the surface of the recording paper, potentially leading to recording problems. 
   To resolve this problem, Japanese unexamined patent application publications Nos. 2001-80145 and 2002-307769 proposed providing paper support members in the groove formed in the platen. These paper support members rotate along with the recording paper as the recording paper is conveyed. The paper support members support the recording paper advancing over the groove, while moving in the width direction of the groove. Hence, the paper support members can support the recording paper when the recording paper is conveyed over the groove formed in the platen. 
   SUMMARY 
   However, since the conventional paper support members rotate about a prescribed rotational shaft (see Japanese unexamined patent application publication No. 2001-80145), the distal edges of the paper support members (the portion contacting the recording paper) first approach and then separate from the recording head side. Therefore, the recording paper is not always supported parallel to the recording head. While this problem can be resolved by sufficiently increasing the rotational radius of the paper support members, doing so would also increase the size of the inkjet-recording device. Some devices have paper support members with surfaces for supporting the recording paper in the shape of an arc centered on the rotational shaft. However, this structure fixes the points at which the recording paper is supported so that the edges of the conveyed recording paper are not always supported. In other words, when the surfaces supporting the recording paper are formed in arc shapes, the recording paper is only supported at the support points and can bend in regions outside the support points (areas in front of or behind the support points), potentially leading to the same recording problems described above. 
   In view of the foregoing, it is an object of the invention to provide an inkjet-recording device capable of performing high-speed borderless recording while ensuring that the edges of the conveyed recording paper are always supported on the platen. 
   In order to attain the above and other objects, the invention provides an inkjet-recording device including a recording head, a platen, a conveying member, and a movable supporting member. The recording head ejects ink droplets onto a recording medium. The platen is disposed in confrontation with the recording head to support the recording medium while keeping a predetermined distance from the recording head. The conveying member conveys the recording medium in a conveying direction. The movable supporting member is linked to the conveying member to slide in the conveying direction while supporting the recording medium. 
   Another aspect of the invention provides a driving unit for sliding a movable supporting member from a first part to a second part in a conveying direction of a recording medium while supporting the recording medium on a platen. The movable supporting member has an engaging portion. The driving unit includes a rotating plate having a rotational shaft, rotatable about the rotational shaft, and formed with a guide groove engagable with the engaging portion to guide the engaging portion in the conveying direction as the rotating plate rotates. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects, features and advantages of the invention will become more apparent from reading the following description of the preferred embodiments taken in connection with the accompanying drawings in which: 
       FIG. 1  is an external perspective view of a multifunction device according to a first embodiment of the invention; 
       FIG. 2  is a vertical cross-sectional view of the multifunction device according to the first embodiment; 
       FIG. 3  is an enlarged cross-sectional view of the multifunction device according to the first embodiment; 
       FIG. 4  is a plan view of a printer section in the multifunction device of the first embodiment; 
       FIG. 5  is a perspective view of a printer section in the multifunction device of the first embodiment; 
       FIG. 6  is an enlarged bottom view of an inkjet recording head in the multifunction device of the first embodiment; 
       FIG. 7  is an enlarged cross-sectional view showing the internal structure of the inkjet recording head in the multifunction device of the first embodiment; 
       FIG. 8  is a block diagram showing the structure of a controller in the multifunction device of the first embodiment; 
       FIG. 9  is an enlarged perspective view of the printer section in  FIG. 5 ; 
       FIG. 10  is an enlarged perspective view of a movable support piece in the multifunction device of the first embodiment; 
       FIG. 11  is an enlarged perspective view of the movable support piece in the multifunction device of the first embodiment; 
       FIG. 12  is an enlarged perspective view of an interlock mechanism in the multifunction device of the first embodiment; 
       FIG. 13  is an enlarged perspective view of a rotating plate in the multifunction device of the first embodiment; 
       FIG. 14  is a bottom view of the rotating plate in the multifunction device of the first embodiment; 
       FIG. 15  is a timing chart showing the timing for conveying recording paper and sliding the movable support piece during borderless recording; 
       FIGS. 16A-16D  are explanatory diagrams showing the sequence of displacement in the movable support piece when conveying recording paper; 
       FIG. 17  is an enlarged perspective view of a multifunction device according to a variation of the first embodiment; 
       FIG. 18  is an enlarged perspective view of a platen in a multifunction device according to a second embodiment; 
       FIG. 19  is a front view of the platen in the multifunction device of the second embodiment; 
       FIG. 20  is a view of the platen indicated by an arrow XX in  FIG. 19 ; 
       FIG. 21  is a view of the platen indicated by an arrow XXI in  FIG. 19 ; 
       FIG. 22  is a bottom view of the platen in the multifunction device of the second embodiment; 
       FIG. 23  is a bottom view of the platen in the multifunction device of the second embodiment; 
       FIGS. 24A-C  is an explanatory diagram showing the relationship between the movable support piece and the recording paper according to the second embodiment; and 
       FIGS. 25A-C  is an explanatory diagram showing the relationship between the movable support piece and the recording paper according to the second embodiment. 
   

   DETAILED DESCRIPTION 
   Next, the invention will be described in detail based on preferred embodiments, while referring to the accompanying drawings. These embodiments are merely examples of the invention, and it should be apparent to those skilled in the art that many modifications and variations may be made therein without departing from the spirit of the invention. 
   First Embodiment 
     FIG. 1  is a perspective view showing an external appearance of a multifunction device  1  that incorporates a movable support piece drive member (rotating plate  125  described later) according to the first embodiment of the invention.  FIG. 2  is a vertical cross-sectional view showing the internal structure of the multifunction device  1 . 
   The multifunction device  1  possesses a printer function, scanner function, copier function, and facsimile function, specifically, is integrally provided with a printer section  2  in the lower section and configured of an inkjet-recording device; and a scanner section  3  in the upper section. Alternatively, it is possible to omit all functions from the multifunction device  1  except the printer function. For example, the multifunction device  1  may be configured as a stand-alone printer by omitting the scanner section  3 . The features of the preferred embodiment are as follows. As will be described later with reference to  FIG. 9 , the printer section  2  includes a platen  42  for supporting a recording paper, a movable support piece  88  provided on the platen  42 , and an interlock mechanism  105  for sliding the movable support piece  88  in response to conveyance of the recording paper. Specifically, the interlock mechanism  105  is provided with the rotating plate  125  (see  FIG. 12 ) for sliding the movable support piece  88  in synchronization with the conveyance of the recording paper. 
   The printer section  2  of the multifunction device  1  is primarily connected to a computer or other external information device for recording text and images on a recording paper based on print data including text or image data transmitted from the computer or the like. The multifunction device  1  may also be connected to a digital camera or the like and may record image data inputted from the digital camera on recording paper. Also, the multifunction device  1  may be loaded with a memory card or other storage medium and may be capable of recording image data and the like stored on the storage medium on recording paper. 
   As shown in  FIG. 1 , the multifunction device  1  is substantially shaped as a thin rectangular parallelepiped with greater width and depth dimensions than the height dimension. The printer section  2  provided in the lower section of the multifunction device  1  has an opening  2   a  formed in the front surface thereof. A feeding tray  20  and a discharge tray  21  are stacked vertically in two levels in the opening  2   a . The feeding tray  20  is capable of accommodating recording paper of various sizes as large as the A4 size and including the B5 size and postcard size. The feeding tray  20  includes a slidable tray  20   a  that can be pulled outward when needed, as shown in  FIG. 2 , to expand the surface area of the tray. With this construction, the feeding tray  20  can accommodate legal sized recording paper, for example. Recording paper accommodated in the feeding tray  20  is supplied into the printer section  2  to undergo a desired image recording process, and is subsequently discharged onto the discharge tray  21 . 
   The scanner section  3  disposed in the upper section of the multifunction device  1  is a flatbed scanner. As shown in  FIGS. 1 and 2 , the multifunction device  1  includes an original cover  30  on the top thereof that is capable of opening and closing, and a platen glass  31  disposed below the original cover  30  and an image sensor  32  disposed below the platen glass  31 . The platen glass  31  functions to support an original document when an image on the document is being scanned. The image sensor  32  is capable of reciprocating in the width direction of the multifunction device  1  (vertical direction in  FIG. 2 ), wherein the main scanning direction of the image sensor  32  is the depth direction of the multifunction device  1  (left-to-right direction in  FIG. 2 ). 
   A control panel  4  is provided on the top front surface of the multifunction device  1  for operating the printer section  2  and the scanner section  3 . The control panel  4  is configured of various operating buttons and a liquid crystal display. The multifunction device  1  operates based on operating instructions inputted through the control panel  4  and, when connected to an external computer, operates based on instructions that the computer transmits through a printer driver or a scanner driver. A slot section  5  in which various small memory cards or other storage media can be inserted is provided in the upper left section of the multifunction device  1  on the front surface thereof (see  FIG. 1 ). A user can input operating instructions via the control panel  4  to read image data stored on a memory card that is inserted into the slot section  5  and to display the image data on the liquid crystal display of the control panel  4 , and can further input instructions to record a desired image on recording paper using the printer section  2 . 
   Next, the internal structure of the multifunction device  1 , and particularly the structure of the printer section  2 , will be described. 
   As shown in  FIG. 2 , a sloped separating plate  22  is disposed near the rear side of the feeding tray  20  provided in the lower section of the multifunction device  1  for separating recording paper stacked in the feeding tray  20  and guiding the separated paper upward. A paper-conveying path  23  leads upward from the sloped separating plate  22 , curves toward the front of the multifunction device  1 , and extends in the rear-to-front direction therefrom. The paper-conveying path  23  passes an image-recording unit  24  and leads to the discharge tray  21 . Hence, the paper-conveying path  23  guides recording paper conveyed from the feeding tray  20  along U-shaped path that curves upward and back in the opposite direction to the image-recording unit  24 . After the image-recording unit  24  has recorded an image on the paper, the paper continues along the paper-conveying path  23  and is discharged onto the discharge tray  21 . 
     FIG. 3  is an enlarged cross-sectional view showing the principal structure of the printer section  2 . 
   As shown in  FIG. 3 , a feeding roller  25  is disposed above the feeding tray  20  for feeding recording paper stacked in the feeding tray  20  to the paper-conveying path  23 . The feeding roller  25  is supported on an end of a feeding arm  26 . A linefeed motor  71  (see  FIG. 5 ) drives the feeding roller  25  to rotate with a driving force transmitted to the feeding roller  25  via a drive transmitting mechanism  27 . The drive transmitting mechanism  27  includes a plurality of engaged gears. 
   The feeding arm  26  is rotatably supported on a base end  26   a . When the feeding arm  26  pivots about the base end  26   a , the feeding roller  25  moves vertically so as to contact and separate from the feeding tray  20 . The feeding arm  26  is urged to rotate downward into contact with the feeding tray  20  by its own weight, a spring, or the like, and retracts upward when the feeding tray  20  is inserted or removed. When the feeding arm  26  is pivoted downward, the feeding roller  25  supported on the end of the feeding arm  26  contacts the recording paper in the feeding tray  20  with pressure. As the feeding roller  25  rotates in this position, a frictional force generated between the surface of the feeding roller  25  and the recording paper conveys the topmost sheet of the recording paper toward the sloped separating plate  22 . The leading edge of this sheet of recording paper contacts the sloped separating plate  22  and is guided upward by the sloped separating plate  22  onto the paper-conveying path  23 . In some cases, when the feeding roller  25  is conveying the topmost sheet of recording paper, friction or static electricity between the topmost sheet and the underlying sheet causes the underlying sheet to be conveyed together with the topmost sheet. However, the underlying sheet is restrained when contacting the sloped separating plate  22 . 
   Excluding the section in which the image-recording unit  24  and the like are provided, the paper-conveying path  23  is configured of an outer guide surface and an inner guide surface that oppose each other with a prescribed gap formed therebetween. For example, a curved section  17  of the paper-conveying path  23  may be configured near the rear side of the multifunction device  1  by fixing an outer guide member  18  and an inner guide member  19  to a frame of the multifunction device  1 . Rollers  16  are provided along the paper-conveying path  23 , and particularly in the curved section of the paper-conveying path  23 . The rollers  16  are rotatably provided on axes extending in the width direction of the paper-conveying path  23  The surfaces of the rollers  16  are exposed from the outer guide surface. These rollers  16  facilitate the smooth conveyance of recording paper in the curved section of the paper-conveying path  23 . 
   As shown in  FIG. 3 , the image-recording unit  24  is disposed on the paper-conveying path  23 . The image-recording unit  24  includes a carriage  38  that reciprocates in the main scanning direction, and an inkjet recording head  39  mounted in the carriage  38 . Ink cartridges disposed in the multifunction device  1  independently of the inkjet recording head  39  supply ink in the colors cyan (C), magenta (M), yellow (Y), and black (Bk) to the inkjet recording head  39  via ink tubes  41  (see  FIG. 4 ) While the carriage  38  reciprocates, microdroplets of ink in these colors are selectively ejected from the inkjet recording head  39  onto the recording paper conveyed over the platen  42  to record an image on the paper. Note that the ink cartridge is not shown in  FIGS. 3 and 4 . 
     FIG. 4  is a plan view showing the principal structure of the printer section  2 , and primarily the structure from approximately the center of the printer section  2  to the rear surface side thereof.  FIG. 4  is a perspective view showing the structure of the image-recording unit  24  in the printer section  2 . 
   As shown in  FIGS. 4 and 5 , a pair of guide rails  43  and  44  is disposed above the paper-conveying path  23 . The guide rails  43  and  44  are disposed at a prescribed distance from each other in the paper-conveying direction (from top to bottom in  FIG. 4 ) and extend in a direction orthogonal to the paper-conveying direction (left-to-right direction in  FIG. 4 ) The guide rails  43  and  44  are disposed inside the casing of the printer section  2  and constitute part of the frame supporting components of the printer section  2 . The carriage  38  is disposed across both the guide rails  43  and  44  so as to be capable of sliding in a direction orthogonal to the paper-conveying direction. Accordingly, the guide rails  43  and  44  are disposed so as to be substantially horizontal and are juxtaposed in the paper-conveying direction, thereby decreasing the height of the printer section  2  and achieving a thinner device. 
   The guide rail  43  disposed on the upstream side of the guide rail  44  in the paper-conveying direction is plate-shaped with a dimension in the width direction of the paper-conveying path  23  (left-to-right direction in  FIG. 4 ) greater than the reciprocating range of the carriage  38 . The guide rail  44  disposed on the downstream side is also plate-shaped with a dimension in the width direction of the paper-conveying path  23  substantially the same as that of the guide rail  43 . The carriage  38  is capable of sliding in the longitudinal direction of the guide rails  43  and  44  with an upstream end of the carriage  38  supported on the guide rail  43  and a downstream end supported on the guide rail  44 . 
   The guide rail  44  has an edge part  45  bent upward at substantially a right angle from the upstream side of the guide rail  44 . The carriage  38  supported on the guide rails  43  and  44  has a pair of rollers or other gripping members for slidably gripping the edge part  45 . Hence, the carriage  38  can slide in a direction orthogonal to the paper-conveying direction, while being positioned relative to the paper-conveying direction. In other words, the carriage  38  is slidably supported on the guide rails  43  and  44  and is capable of reciprocating in a direction orthogonal to the paper-conveying direction with the edge part  45  of the guide rail  44  serving as a positional reference. Although not shown in the drawings, a lubricating agent such as grease is applied to the edge part  45  to facilitate sliding of the carriage  38 . 
   A belt drive mechanism  46  is provided on the top surface of the guide rail  44 . The belt drive mechanism  46  is configured of a drive pulley  47  and a follow pulley  48  disposed near widthwise ends of the paper-conveying path  23 , and an endless timing belt  49  stretched around the drive pulley  47  and follow pulley  48  and having teeth on the inside surface thereof. A carriage motor  73  (see  FIG. 5 ) generates a driving force that is transmitted to the shaft of the drive pulley  47  for rotating the drive pulley  47 . The rotation of the drive pulley  47  causes the timing belt  49  to move circuitously. Although the timing belt  49  is an endless belt in the preferred embodiment, a belt having ends may also be used by fixing both ends to the carriage  38 . 
   The bottom surface of the carriage  38  is fixed to the timing belt  49  so that the circuitous movement of the timing belt  49  causes the carriage  38  to reciprocate over the guide rails  43  and  44  while the edge part  45  maintains the position of the carriage  38  relative to the paper-conveying direction. The inkjet recording head  39  is mounted in the carriage  38  having this construction so that the inkjet recording head  39  also reciprocates in the width direction of the paper-conveying path  23 . Here, the width direction of the paper-conveying path  23  is the main scanning direction. 
   As shown in  FIG. 4 , an encoder strip  50  for a linear encoder  77  (see  FIG. 8 ) is provided along the guide rail  44 . The encoder strip  50  is a strip-like member formed of a transparent resin. A pair of support parts  33  and  34  is formed on the top surface of the guide rail  44 , with one disposed on each widthwise end of the guide rail  44  (each end in the reciprocating direction of the carriage  38 ). The encoder strip  50  extends over the edge part  45  with the ends of the encoder strip  50  engaged in the support parts  33  and  34 . While not shown in the drawings, one of the support parts  33  and  34  has a leaf spring for engaging the end of the encoder strip  50 . The leaf spring prevents slack in the encoder strip  50  by applying tension to the encoder strip  50  in the longitudinal direction, while being elastically deformable so that the encoder strip  50  can bend when an external force is applied thereto. 
   Light-transmitting parts allowing the passage of light and light-blocking parts preventing the passage of light are alternately disposed along the length of the encoder strip  50  at a prescribed pitch. An optical sensor  35  configured of a transmission sensor is disposed on the top surface of the carriage  38  at a position opposing the encoder strip  50 . The optical sensor  35  reciprocates together with the carriage  38  along the length of the encoder strip  50  and detects the pattern formed on the encoder strip  50 . A head controlling circuit board is provided in the inkjet recording head  39  for controlling ink ejection. The head controlling circuit board outputs a pulse signal based on detection signals from the optical sensor  35 . By determining the position of the carriage  38  based on this pulse signal, it is possible to control the reciprocating motion of the carriage  38 . The head controlling circuit board is covered by a head cover of the carriage  38  and is therefore not visible in  FIGS. 4 and 5 . 
   As shown in  FIGS. 3 and 4 , the platen  42  is disposed on the bottom of the paper-conveying path  23  opposing the inkjet recording head  39 . The platen  42  spans a central portion within the reciprocating range of the carriage  38  through which the recording paper passes. The width of the platen  42  is sufficiently larger than the maximum width of recording paper that can be conveyed in the multifunction device  1  so that both widthwise edges of the recording paper pass over the platen  42 . The platen  42  is provided with a movable support piece  88  (see  FIG. 5 ) described in detail later. The movable support piece  88  follows the movement of the recording paper in the paper-conveying direction as the recording paper is conveyed over the platen  42 , thereby maintaining support of the edges of the recording paper at all times. 
   As shown in  FIG. 4 , a maintenance unit including a purge mechanism  51  and a waste ink tray  84  is provided in a region through which the recording paper does not pass, that is, in a region outside the image-recording range of the inkjet recording head  39 . The purge mechanism  51  functions to draw out air bubbles and foreign matter from nozzles  53  (see  FIG. 6 ) in the inkjet recording head  39 . The purge mechanism  51  includes a cap  52  for covering the nozzles  53 , a pump mechanism (not shown) connected to the inkjet recording head  39  via the cap  52 , and a moving mechanism (not shown) for moving the cap  52  to contact or separate from the nozzles  53  of the inkjet recording head  39 . In  FIG. 4 , the pump mechanism and the moving mechanism are positioned beneath the guide rail  44  and are therefore not visible. 
   When an operation is performed to remove air bubbles and the like from the inkjet recording head  39 , the carriage  38  is moved so that the inkjet recording head  39  is positioned above the cap  52 . Subsequently, the moving mechanism moves the cap  52  upward against the inkjet recording head  39  so as to form a seal over the nozzles  53  formed in the bottom surface of the inkjet recording head  39 . The pump mechanism then generates negative pressure in the cap  52  to draw out ink and air bubbles and foreign matter included in the ink from the nozzles  53 . 
   The waste ink tray  84  is disposed on the top surface of the platen  42  outside of the image-recording range, but within the reciprocating range of the carriage  38  for receiving ink that has been flushed out of the inkjet recording head  39 . The inside of the waste ink tray  84  is lined with felt for absorbing and holding the flushed ink. The maintenance unit having this construction can perform such maintenance as removing air bubbles and mixed ink of different colors from the inkjet recording head  39 , and preventing the inkjet recording head  39  from drying out. 
   As shown in  FIG. 1 , a door  7  is provided on the front surface of the printer section  2  casing and is capable of opening and closing over the same. Opening the door  7  exposes a cartridge mounting section on the front side of the printer section  2 , enabling the user to mount ink cartridges in or remove ink cartridges from the cartridge mounting section. While not shown in the drawings, the cartridge mounting section is partitioned into four accommodating chambers for individually accommodating ink cartridges filled with ink of the colors cyan, magenta, yellow, and black. Four ink tubes  41  corresponding to the four ink colors lead from the cartridge accommodating section to the carriage  38  As described above, ink is supplied from the ink cartridges mounted in the cartridge accommodating section to the inkjet recording head  39  mounted on the carriage  38  via the ink tubes  41 . 
   The ink tubes  41  are tubes formed of synthetic resin and are flexible so as to be able to bend when the carriage  38  reciprocates. As shown in  FIG. 4 , the ink tubes  41  extend from the cartridge accommodating section along the width direction of the device to a position near the center thereof, at which position the ink tubes  41  are fixed to a fixing clip  36  on the body of the device. A section of the ink tubes  41  from the fixing clip  36  to the carriage  38  forms a U-shaped curved that is not fixed to the device body or the like. This U-shaped section changes in shape as the carriage  38  reciprocates. The section of the ink tubes  41  extending from the fixing clip  36  to the cartridge mounting section is not shown in  FIG. 4 . 
   Specifically, the section of the ink tubes  41  between the fixing clip  36  and carriage  38  leads in one direction along the reciprocating path of the carriage  38  and subsequently reverses directions, forming a curved section. In other words, this section of the ink tubes  41  is substantially U-shaped in a plan view. At the carriage  38 , the four ink tubes  41  are horizontally juxtaposed along the paper-conveying direction and extend in the reciprocating direction of the carriage  38 . However, the four ink tubes  41  are arranged vertically at the fixing clip  36  to facilitate fixation. The fixing clip  36  has a U-shaped cross-section open on the top. The vertically stacked ink tubes  41  are inserted through this opening and are integrally held by the fixing clip  36 . In this way, the four ink tubes  41  curve along a U-shaped path from the carriage  38  to the fixing clip  36  while twisting from a horizontally juxtaposed relationship to a vertically juxtaposed relationship. 
   The four ink tubes  41  have substantially the same length from the carriage  38  to the fixing clip  36 . The ink tube  41  positioned farthest upstream in the paper-conveying direction at the carriage  38  is positioned on the top at the fixing clip  36 . The ink tube  41  disposed next in order from the upstream side at the carriage  38  is disposed next in order vertically at the fixing clip  36 . This process is repeated so that the ink tubes  41  arranged from the upstream side to the downstream side in the paper-conveying direction at the carriage  38  are arranged in order from top to bottom at the fixing clip  36 . Being substantially equivalent in length, the ink tubes  41  curve so that the center of the curved section of each ink tube  41  is offset in the paper-conveying direction according to the order in which the ink tubes  41  are juxtaposed in the paper-conveying direction. As a result, the four ink tubes  41  have a vertically sloped arrangement in the curved section, thereby minimizing interference among the ink tubes  41  as the ink tubes  41  change shape to follow the reciprocating motion of the carriage  38 . In the preferred embodiment, four of the ink tubes  41  are provided. However, even if the number of the ink tubes  41  is increased, the ink tubes  41  can be arranged in the same juxtaposed relationship, with the ink tube  41  disposed farthest upstream in the paper-conveying direction at the carriage  38  positioned on top at the fixing clip  36 . 
   A flat cable  85  transfers recording signals and the like from a main circuit board constituting a controller  64  (see  FIG. 8 ) to a head control circuit board in the inkjet recording head  39 . While not shown in  FIG. 4 , the main circuit board is disposed near the front of the printer section  2  (the near side in  FIG. 4 ). The flat cable  85  is an insulated ribbon cable configured of conductors for transmitting electric signals, the conductors being coated in a synthetic resin film such as a polyester film or the like. The flat cable  85  electrically connects the main circuit board to the head control circuit board. 
   The flat cable  85  is flexible and bends in response to the reciprocation of the carriage  38 . As shown in  FIG. 4 , the flat cable  85  extends from the carriage  38  in one direction along the reciprocating path of the carriage  38 , and subsequently reverses directions and extends to a fixing clip  86 , thereby forming a curved section. In other words, the flat cable  85  follows a path that is substantially U-shaped in a plan view with the top and bottom surfaces of the ribbon shape oriented vertically. In other words, the top and bottom surfaces of the flat cable  85  fall in vertical planes, while a normal to these surfaces is oriented horizontally. Further, the direction in which the flat cable  85  extends from the carriage  38  and the extending direction of the ink tubes  41  are identical to the reciprocating direction of the carriage  38  The end of the flat cable  85  fixed to the carriage  38  is electrically connected to the head control circuit board mounted in the carriage  38 . The other end of the flat cable  85  fixed to the fixing clip  86  extends to and is electrically connected to the main circuit board. The section of the flat cable  85  curved in a U shape is not fixed to any member, but changes in shape as the carriage  38  reciprocates, similar to the ink tubes  41 . A rotating support member  90  is provided for supporting the ink tubes  41  and flat cable  85  as these components change in shape when the carriage  38  reciprocates. The rotating support member  90  is rotatably supported on a shaft-receiving part  91  at one end thereof. Hence, the rotating support member  90  is capable of pivoting about the shaft-receiving part  91 . 
   A restricting wall  37  is provided on the front surface of the printer section  2  extending in the width direction (left-to-right direction in  FIG. 4 ) The restricting wall  37  has a vertical surface that is contacted by the ink tubes  41  and extends along a straight line following the reciprocating direction of the carriage  38 . The restricting wall  37  is disposed in the area that the ink tubes  41  extend from the fixing clip  36  and is set to a height sufficient for all four ink tubes  41  juxtaposed vertically to contact. The ink tubes  41  extend from the fixing clip  36  along the restricting wall  37 . By contacting the inside surface of the restricting wall  37 , the ink tubes  41  are restricted from expanding in a direction toward the front surface of the printer section  2 , that is, away from the carriage  38 . 
   The fixing clip  36  is disposed near the widthwise center of the printer section  2 . The fixing clip  36  fixes the ink tubes  41  so that the ink tubes  41  extend toward the restricting wall  37 . More specifically, the vertical surface of the restricting wall  37  and the direction in which the ink tubes  41  extend from the fixing clip  36  forms an obtuse angle less than 180 degrees in a plan view. The ink tubes  41  are flexible, but have a degree of stiffness (flexural rigidity). Hence, the ink tubes  41  press against the surface of the restricting wall  37  when extending at an angle from the fixing clip  36  to the restricting wall  37 . Consequently, the range in which the ink tubes  41  follow the restricting wall  37  expands within the reciprocating range of the carriage  38 , thereby reducing the area in the section from the curved section of the ink tubes  41  to the carriage  38  that expands toward the carriage  38 . 
   The fixing clip  86  is disposed near the widthwise center of the printer section  2  further inside than the fixing clip  36 . The fixing clip  86  fixes the flat cable  85  so that the flat cable  85  expands toward the restricting wall  37 . Hence, the vertical surface of the restricting wall  37  and the direction in which the flat cable  85  extends from the fixing clip  86  forms an obtuse angle smaller than 180 degrees in a plan view. The flat cable  85  is flexible, but has a degree of stiffness (flexural rigidity). Hence, the flat cable  85  presses against the surface of the restricting wall  37  when extending at an angle from the fixing clip  86  to the restricting wall  37 . Consequently, the range in which the flat cable  85  follows the restricting wall  37  expands within the reciprocating range of the carriage  38 , thereby reducing the area in the section from the curved section of the flat cable  85  to the carriage  38  that expands toward the carriage  38 . 
     FIG. 6  is a bottom view of the inkjet recording head  39  showing the nozzle surface. 
   As shown in  FIG. 6 , the nozzles  53  are formed in the bottom surface of the inkjet recording head  39  in rows extending in the paper-conveying direction for each of the ink colors cyan, magenta, yellow, and black. The paper-conveying direction is vertically upward in  FIG. 6 , while the main scanning direction of the carriage  38  is left-to-right. A row of nozzles  53  is formed for each of the ink colors in the paper-conveying direction, and the rows are juxtaposed in the main scanning direction of the carriage  38 . The pitch and number of the nozzles  53  arranged in the paper-conveying direction for each color are set appropriately with consideration for the resolution of the images to be recorded and the like. It is also possible to increase or decrease the number of rows of the nozzles  53  to correspond to the number of ink colors. 
     FIG. 7  is an enlarged cross-sectional view showing part of the internal structure of the inkjet recording head  39 , 
   As shown in  FIG. 7 , a cavity  55  is formed in the inkjet recording head  39  upstream of the nozzle  53  for each nozzle  53  formed in the bottom surface of the inkjet recording head  39 . Each cavity  55  is provided with a piezoelectric element  54  that deforms to shrink the capacity of the cavity  55  when a prescribed voltage is applied thereto. Changes in the volume of the cavity  55  cause ink accommodated in the cavity  55  to eject from the nozzle  53  as an ink droplet. 
   While the cavity  55  is provided for each nozzle  53 , a single manifold  56  is formed along the plurality of cavities  55 . The manifold  56  is provided for each of the colors cyan, magenta, yellow, and black. A buffer tank  57  is provided upstream of the cavity  55 . One buffer tank  57  is provided for each color cyan, magenta, yellow, and black. An ink supply opening  58  is formed in a side wall of the buffer tank  57  for supplying ink from the ink tubes  41  into the buffer tank  57 . By temporarily storing ink in the buffer tank  57 , air bubbles generated in the ink in the ink tubes  41  are captured and prevented from entering the cavity  55  and manifold  56 . The pump mechanism removes air bubbles captured in the buffer tank  57  by suction via an air bubble outlet  59 . Ink supplied from the buffer tank  57  to the manifold  56  is distributed by the manifold  56  to each of the cavities  55 . 
   This construction forms an ink channel by which ink of the respective color supplied from the respective ink cartridge via the ink tube  41  flows to the cavity  55  via the buffer tank  57  and manifold  56 . In this way, ink of each color cyan, magenta, yellow, and black supplied via these ink channels is subsequently ejected from the nozzle  53  onto recording paper as ink droplets when the piezoelectric element  54  deforms. 
   As shown in  FIG. 3 , a conveying roller  60  and a pinch roller are disposed on the upstream side of the image-recording unit  24  while hidden from view by other components in  FIG. 3 , the pinch roller contacts the bottom side of the conveying roller  60  with pressure. The conveying roller  60  and the pinch roller receive and pinch a sheet of recording paper conveyed along the paper-conveying path  23  and convey the recording paper over the platen  42 . Pairs of discharge rollers  62  and spur rollers  63  are disposed on the downstream side of the image-recording unit  24  for pinching and conveying the recording paper to the discharge tray  21  after an image has been recorded on the recording paper. A driving force transmitted from the linefeed motor  71  drives the conveying roller  60  and discharge rollers  62  intermittently at prescribed linefeed amounts. Rotation of the conveying roller  60  and discharge rollers  62  is synchronized. Further, a rotary encoder  76  (see  FIG. 8 ) is provided on the conveying roller  60 , and has an optical sensor  82  (see  FIG. 5 ) for detecting a pattern on an encoder disk  61  rotating together with the conveying roller  60 . The rotation of the conveying roller  60  and discharge rollers  62  is controlled based on detection signals from the rotary encoder  76 . 
   Since the spur rollers  63  press against paper that has been printed, the roller surface of the spur rollers  63  is shaped like a spur with alternating protruding and depressed parts so as to not degrade the image recorded on the paper. The spur rollers  63  are capable of sliding in a direction for contacting or separating from the discharge rollers  62 . A coil spring urges the spur rollers  63  to press against the discharge rollers  62 . When recording paper becomes interposed between the discharge rollers  62  and spur rollers  63 , the spur rollers  63  recede against the urging force of the coil spring by a distance equivalent to the thickness of the recording paper, while pressing the recording paper against the discharge rollers  62 . In this way, the rotational force of the discharge rollers  62  is reliably transmitted to the recording paper. The pinch roller is similarly provided against the conveying roller  60 , pressing the recording paper against the conveying roller  60  so that the rotational force of the conveying roller  60  is reliably transmitted to the recording paper. 
   A registration sensor  95  is disposed on the paper-conveying path  23  upstream of the conveying roller  60 . The registration sensor  95  includes a probe shown in  FIG. 3 , and an optical sensor (not shown). The probe is capable of protruding into and retracting from the paper-conveying path  23  and is elastically urged to protrude into the paper-conveying path  23  at all times. When a sheet of recording paper conveyed along the paper-conveying path  23  contacts the probe, the probe rotates out of the paper-conveying path  23 . The protruding and retracting motion of the probe switches the optical sensor on and off. Therefore, the position of the leading or trailing edge of the recording paper in the paper-conveying path  23  is detected based on the protruding and retracting of the probe. 
   In addition to feeding recording paper from the feeding tray  20 , the linefeed motor  71  in the multifunction device  1  of the preferred embodiment functions to convey recording paper to a position over the platen  42  and to discharge recording paper onto the discharge tray  21  after recording has completed. In other words, the linefeed motor  71  drives the conveying roller  60  (see  FIG. 5 ), drives the feeding roller  25  via the drive transmitting mechanism  27  as described above (see  FIG. 3 ), and drives a discharge roller shaft on which the discharge rollers  62  are mounted via a drive transmitting mechanism  83  (see  FIG. 5 ) The drive transmitting mechanism  83  may be configured of a gear train, for example, or a timing belt suitable for the mounting space available. 
     FIG. 8  is a block diagram showing the structure of the controller  64  for the multifunction device  1 . 
   The controller  64  controls the overall operations of the multifunction device  1 , including not only the scanner section  3 , but also the printer section  2 . The controller  64  is configured of a main circuit board connected to the flat cable  85 . Since the structure of the scanner section  3  is not important in the present invention, a detailed description of this structure has been omitted. 
   As shown in  FIG. 8 , the controller  64  is configured of a microcomputer primarily including a CPU (central processing unit)  65 , a ROM (read only memory)  66 , a RAM (random access memory)  67 , and a EEPROM (electrically erasable and programmable ROM)  68 . These components are connected to an ASIC (application specific integrated circuit)  70  via a bus  69 . 
   The ROM  66  stores programs and the like for controlling various operations of the multifunction device  1 . The RAM  67  functions as a storage area or a work area for temporarily saving various data used by the CPU  65  in executing the programs. The EEPROM  68  stores settings, flags, and the like that must be preserved when the power is turned off. 
   On a command from the CPU  65 , the ASIC  70  generates a phase excitation signal and the like for conducting electricity to the linefeed motor  71 . The signal is applied to a drive circuit  72  of the linefeed motor  71 . By supplying a drive signal to the linefeed motor  71  via the drive circuit  72 , the ASIC  70  can control the rotation of the linefeed motor  71 . 
   The drive circuit  72  drives the linefeed motor  71 , which is connected to the feeding roller  25 , conveying roller  60 , discharge rollers  62 , and purge mechanism  51 . Upon receiving an output signal from the ASIC  70 , the drive circuit  72  generates an electric signal for rotating the linefeed motor  71 . When the linefeed motor  71  rotates, the rotational force of the linefeed motor  71  is transferred to the feeding roller  25 , conveying roller  60 , discharge rollers  62 , and purge mechanism  51  via a drive mechanism well known in the art that includes gears, drive shafts, and the like. In other words, in addition to feeding recording paper from the feeding tray  20 , the linefeed motor  71  in the multifunction device  1  of the preferred embodiment functions to convey recording paper to a position over the platen  42  and to discharge recording paper onto the discharge tray  21  after recording is completed. 
   Similarly, upon receiving a command from the CPU  65 , the ASIC  70  generates a phase excitation signal and the like for supplying electricity to the carriage motor  73  and applies this signal to a drive circuit  74  of the carriage motor  73 . By supplying a drive signal to the carriage motor  73  via the drive circuit  74 , the ASIC  70  can control the rotation of the carriage motor  73 . 
   The drive circuit  74  functions to drive the carriage motor  73 . Upon receiving an output signal from the ASIC  70 , the drive circuit  74  generates an electric signal for rotating the carriage motor  73 . When the carriage motor  73  rotates, the rotational force of the carriage motor  73  is transferred to the carriage  38  via the belt drive mechanism  46 , thereby scanning the carriage  38  in a reciprocating motion. In this way, the controller  64  can control the reciprocation of the carriage  38 . 
   A drive circuit  75  is provided for driving the inkjet recording head  39  at a prescribed timing. The ASIC  70  generates and outputs a signal to the drive circuit  75  based on a drive control procedure received from the CPU  65 . The drive circuit  75  drives the inkjet recording head  39  based on the output signal received from the ASIC  70 . The drive circuit  75  is mounted in the head control circuit board. When an output signal is transferred from the main circuit board constituting the controller  64  to the head control circuit board via the flat cable  85 , the drive circuit  75  drives the inkjet recording head  39  to selectively eject ink of each color onto the recording paper at a prescribed timing. 
   The ASIC  70  is also connected to the rotary encoder  76  for detecting the rotated amount of the conveying roller  60 , the linear encoder  77  for detecting the position of the carriage  38 , and the registration sensor  95  for detecting the leading and trailing edges of the recording paper. When the power of the multifunction device  1  is turned on, the carriage  38  is moved to one end of the guide rails  43  and  44  and the detection position of the linear encoder  77  is initialized. When the carriage  38  moves from this initial position over the guide rails  43  and  44 , the optical sensor  35  provided on the carriage  38  detects the pattern on the encoder strip  50  and outputs a pulse signal based on these detections The controller  64  determines the distance that the carriage  38  has moved based on the number of pulse signals. According to this detected movement, the controller  64  controls the rotation of the carriage motor  73  in order to control the reciprocating motion of the carriage  38 . The controller  64  also determines the leading and trailing edge positions of recording paper based on a signal outputted from the registration sensor  95  and an encoder amount detected by the rotary encoder  76 . When the leading edge of a sheet of recording paper arrives at a prescribed position on the platen  42 , the controller  64  begins controlling the rotation of the linefeed motor  71  for conveying the recording paper intermittently at prescribed linefeed widths. The linefeed width is set based on a resolution and the like inputted as recording conditions. 
   The ASIC  70  is also connected to the scanner section  3 ; the control panel  4  for specifying operations of the multifunction device  1 ; the slot section  5  in which various small memory cards can be inserted; a parallel interface  78 , a USB interface  79 , and the like for exchanging data with a personal computer or other external device via a parallel cable or USB cable; and a NCU (network control unit)  80  and a modem  81  for implementing a facsimile function. 
     FIG. 9  is an enlarged perspective view of the platen  42 . 
   As described above, the platen  42  is disposed in opposition to the inkjet recording head  39  (below the inkjet recording head  39  in  FIG. 3 ) for supporting recording paper during an image recording operation. As shown in  FIG. 9 , the platen  42  has an overall long, slender rectangular shape and a thin construction. The platen  42  is positioned with the longitudinal dimension along the main scanning direction, indicated by the arrow  87 . The arrow  89  in the same drawing indicates the paper-conveying direction. 
   The platen  42  includes a frame  100 ; first fixed ribs  102  and second fixed ribs  103  disposed on the frame  100 ; the movable support piece  88  slidably provided on the frame  100 ; and the interlock mechanism  105  described later for sliding the movable support piece  88 . 
   The frame  100  is formed of a synthetic resin or steel plate and constitutes the frame of the platen  42 . The cross-section of the frame  100  is shaped similar to the letter C. Brackets  106  and  107  are disposed one on either end of the frame  100  in the main scanning direction. The brackets  106  and  107  are integrally formed with the frame  100 . The frame  100  is fixed to the multifunction device  1  via the brackets  106  and  107 . 
   A drive mechanism mounting section  108  is disposed on one end of the frame  100  (the near side in  FIG. 9 ). The drive mechanism mounting section  108  is integrally formed with the frame  100  and includes a top plate  110  formed continuously with a top surface  109  of the frame  100 . The top plate  110  is rectangular shaped and functions to support the interlock mechanism  105  described later. 
   The first fixed ribs  102  and second fixed ribs  103  are provided on the top surface  109  of the frame  100 . More specifically, the first fixed ribs  102  are provided on an upstream end of the top surface  109  in the paper-conveying direction and protrude upward toward the inkjet recording head  39  The second fixed ribs  103  are provided on the downstream side of the top surface  109  in the paper-conveying direction and protrude upward. As shown in  FIG. 9 , the first fixed ribs  102  and second fixed ribs  103  in the preferred embodiment are divided into two parts in the paper-conveying direction, but obviously these components may be formed integrally rather than divided. 
   In the preferred embodiment, the first fixed ribs  102  are provided on the multifunction device  109  and juxtaposed in the main scanning direction. Similarly, the second fixed ribs  103  are provided on the top surface  109  and juxtaposed in the main scanning direction. With this construction, a groove  116  is formed between the first fixed ribs  102  and second fixed ribs  103 . As shown in  FIG. 9 , the groove  116  extends in the main scanning direction and expands in the paper-conveying direction. The groove  116  has a width dimension  117  that corresponds to the size of the inkjet recording head  39 . Specifically, the multifunction device  117  of the multifunction device  116  is set wider than an ink ejection range  118  (see  FIG. 6 ) of the inkjet recording head  39 . 
   In the preferred embodiment, the first fixed ribs  102  and second fixed ribs  103  oppose each other in the paper-conveying direction (the direction of the arrow  89 ) with the groove  116  interposed therebetween, as shown in  FIG. 9 . The corners of the first fixed ribs  102  are beveled to form a pair of sloped surfaces. In the preferred embodiment, sloped surfaces are formed in both corners of the first fixed ribs  102  with respect to the paper-conveying direction. However, it is also possible to form a sloped surface in only the upstream corner of the first fixed ribs  102  in the paper-conveying direction. Similarly, the corners of the second fixed ribs  103  are beveled to form a pair of sloped surfaces. While sloped surfaces are formed in both corners of the second fixed ribs  103  with respect to the paper-conveying direction, it is also possible to form a sloped surface in only the upstream corner of the second fixed ribs  103  in the paper-conveying direction. 
   A plurality of slits  119  are formed in the top surface  109  of the frame  100 . The slits  119  extend from the upstream end to the downstream end of the top surface  109  in the paper-conveying direction and are juxtaposed in the main scanning direction. Each slit  119  extends from the region between neighboring first fixed ribs  102  to the region between neighboring second fixed ribs  103 . The movable support piece  88  is fitted into the slits  119  and protrudes upward therefrom. 
     FIG. 10  is an enlarged perspective view of the movable support piece  88 .  FIG. 11  is an enlarged perspective view of the movable support piece  88  viewed from the bottom of the platen  42 .  FIG. 12  is an enlarged perspective view of the interlock mechanism  105 . 
   As shown in  FIGS. 10 and 11 , the movable support piece  88  has a base  120  formed in a box shape, and ribs  121  provided on the base  120 . The ribs  121  are formed in a thin plate shape and protrude from the platen  42  (see  FIG. 9 ) The movable support piece  88  is configured of a synthetic resin or metal. The base  120  has an overall thin plate shape, but is substantially shaped as the letter C in cross section. As shown in  FIG. 9 , the base  120  is fitted inside the frame  100  from the bottom thereof. As shown in  FIG. 10 , a slide roller  93  is rotatably provided on each end of the base  120  in the main scanning direction. The slide roller  93  rotates smoothly relative to the frame  100 . Hence, the base  120  can slide smoothly inside the frame  100  in the paper-conveying direction (the direction indicated by the arrow  89  in  FIGS. 9 and 10 ). 
   The ribs  121  are provided on the top surface of the base  120  and are formed integrally with the base  120  Each of the ribs  121  is formed in a triangular shape. In the preferred embodiment, the ribs  121  are erected on the top surface of the base  120  and are juxtaposed at prescribed intervals in the main scanning direction (the direction indicated by the arrow  87  in  FIG. 10 ). The prescribed intervals correspond to the pitch of the slits  119  (see  FIG. 9 ). Hence, the ribs  121  are inserted through the multifunction device  119  provided in the frame  100  and protrude upward from the top surface  109  of the frame  100 . 
   The ribs  121  constituting the movable support piece  88  are formed in a triangular shape, as described above. More specifically, a beveling process similar to that performed on the first fixed ribs  102  and second fixed ribs  103  is performed on corners  122  and  123  of the ribs  121 , configuring sloped surfaces that slope relative to the paper-conveying direction. In the preferred embodiment, the sloped surfaces are formed on both of the corners  122  and  123  of the ribs  121  in the paper-conveying direction. However, it is possible to form the sloped surface on only the upstream corner  122 . 
   As described above, the interlock mechanism  105  slides the movable support piece  88  in the paper-conveying direction. The interlock mechanism  105  is interposed between a discharge roller shaft  92  and the movable support piece  88  for interlocking the movable support piece  88  with the discharge roller shaft  92 . The movable support piece  88  moves along with the movement of the recording paper as the recording paper is conveyed over the platen  42  so as to support the edges of the recording paper at all times. Specifically, when the recording paper has been conveyed to an upstream edge  94  of the frame  100  in the paper-conveying direction (see  FIG. 9 ), the ribs  121  are moved to meet the recording paper and subsequently slide downstream in the paper-conveying direction as the recording paper is conveyed while supporting the edge of the recording paper. 
   As shown in  FIG. 12 , the interlock mechanism  105  includes the rotating plate  125  driven to rotate by a drive force transmitted from the discharge roller shaft  92  via a drive transmitting mechanism  124 ; and a lever member  126  disposed between the rotating plate  125  and the movable support piece  88  for converting the rotational movement of the rotating plate  125  to translational movement of the movable support piece  88 . 
     FIG. 13  is an enlarged perspective view of the rotating plate  125 .  FIG. 14  is a bottom view of the rotating plate  125 . 
   As shown in FIGS.  12  and  1 . 3 , the rotating plate  125  is disc-shaped and formed of synthetic resin or metal. The rotating plate  125  includes a circular rotating plate part  141 , and a cylindrical shaft  127  erected from a center region in the top surface of the rotating plate part  141 . The cylindrical shaft  127  is rotatably supported on the frame  100  of the platen  42 . As one example, a center rotational shaft (not shown) may be erected in the frame  100 . In this case, the center rotational shaft extends in a direction orthogonal to both the main scanning direction and the paper-conveying direction. The cylindrical shaft  127  is then fitted into the center rotational shaft so as to be capable of rotating freely. Alternatively, the center rotational shaft of the rotating plate  125  may be configured by fitting the cylindrical shaft  127  into the frame  100  directly. In addition, ribs  128  and  129  are erected from the top surface of the rotating plate  125 . The rib  129  is formed with a rectangular cross-section and has an overall circular shape centered on the cylindrical shaft  127 . The rib  128  also has a rectangular cross-section and an overall circular shape centered on the cylindrical shaft  127  and surrounding the rib  129 . 
   The rotating plate  125  is driven in a forward rotation or a reverse rotation through the drive transmitting mechanism  124  described later, where the forward rotation is the direction indicated by the arrow  130 . As shown in  FIG. 13 , a V groove  131  is provided in the rib  128 . The V groove  131  forms two wall surfaces. One of the wall surfaces is a forward restricting surface  132  extending in the axial direction of the cylindrical shaft  127 , that is, a direction orthogonal to the rotating direction of the rotating plate  125 . The other wall surface is a reverse allowing surface  133  extending from the lower edge of the forward restricting surface  132  to the forward rotating side of the rib  128  in the peripheral direction and linking with a top surface  137  of the rib  128 . In addition, a V groove  134  is formed in the rib  129 , producing two wall surfaces therein. One of the wall surfaces is a reverse restricting surface  135  extending in the axial direction of the cylindrical shaft  127 , that is, in a direction orthogonal to the rotating direction of the rotating plate  125 . The other wall surface is a forward allowing surface  136  extending from the lower edge of the reverse restricting surface  135  to the reverse rotating side of the rib  129  in the peripheral direction thereof and linking to a top surface  138  of the rib  129 . As will be described in greater detail below, a locking member  139  and a locking member  140  engage in the V groove  131  and V groove  134 , respectively, for restricting or allowing the forward rotation and reverse rotation of the rotating plate  125 . 
   As shown in  FIGS. 11 and 14 , a guide groove  143  is provided in a back surface  142  of the rotating plate  125 . The guide groove  143  describes a prescribed curved path. More specifically, if a polar coordinate system is set in  FIG. 4  with the center of the cylindrical shaft  127  set as the point of origin and a hypothetical axis  144  extending horizontally along the back surface  142 , then the guide groove  143  follows a curved path that satisfies R=kθ (where k is a constant). In this case, an angle of θ=0 indicates an angle from the point of origin along the left side of the hypothetical axis  144 , and a positive θ indicates an angle in the clockwise direction. More specifically, the curved path depicts an Archimedean spiral, where the distance R from the point of origin to the center of the guide groove  143  has a linear relationship with the angle  0  However, in the preferred embodiment, the curved path conforming to R=kθ falls within the range 0°&lt;=θ&lt;=180°. The curved path formed within this range is symmetrical left-to-right (top-to-bottom in the drawing) about the hypothetical axis  144 . Hence, the guide groove  143  is formed along the Archimedean spiral, which is vertically symmetrical about the hypothetical axis  144 . 
   As shown in  FIG. 11 , the lever member  126  has a slender rod shape and is mounted on the base  120  of the movable support piece  88 . Hence, in the preferred embodiment, the lever member  126  functions as a component of the interlock mechanism  105  and an engaging part for engaging the movable support piece  88  to the rotating plate  125 . More specifically, a distal end  145  of the lever member  126  engages with the bottom surface of the base  120 , while a base end  146  of the lever member  126  engages with the guide groove  143  in the rotating plate  125 . The lever member  126  has a center part  147  supported on the frame  100  of the platen  42 .  FIG. 11  does not show the support structures for the lever member  126  and the frame  100  of the platen  42 . However, this structure may include a support shaft (not shown) provided on the frame  100  in which the center part  147  is rotatably fitted. 
   By fitting the base end  146  of the lever member  126  into the guide groove  143  of the rotating plate  125 , the base end  146  can only be displaced in the paper-conveying direction. However, the distal end  145  of the lever member  126  is fitted into the base  120  and can therefore only be displaced in the paper-conveying direction. Hence, by rotating the rotating plate  125 , the base end  146  of the lever member  126  is guided along the guide groove  143 , while the lever member  126  pivots about the center part  147 . As a result, the distal end  145  of the lever member  126  pivots about the center part  147 . Since the distal end  145  can be displaced in the paper-conveying direction, the base  120  slides in the paper-conveying direction as the distal end  145  pivots. 
   Here, the displacement of the distal end  145  is a prescribed multiple of the displacement in the base end  146 . This multiple more specifically corresponds to the ratio of the distance from the center part  147  to the distal end  145  and the distance from the center part  147  to the base end  146 . Therefore, the displacement of the distal end  145  amplifies the displacement in the base end  146  by the prescribed multiple. In other words, the lever member  126  converts the rotation of the rotating plate  125  to displacement of the base  120  in the paper-conveying direction according to the prescribed ratio. 
   As shown in  FIG. 12 , the drive transmitting mechanism  124  includes a torque limiter  148  provided on the discharge roller shaft  92 , and gears  149 - 151 . The torque limiter  148  includes a flange  153  provided on the discharge roller shaft  92 , a pressure plate  154  contacting the flange  153  via a friction plate  152  such as non-woven fabric, and a coil spring  155  that elastically urges the pressure plate  154  along with the friction plate  152  toward the flange  153 . When the coil spring  155  presses the pressure plate  154  into the flange  153 , a prescribed frictional force is generated therebetween for transmitting a drive force. More specifically, the torque transmitted between the pressure plate  154  and flange  153  is limited. This limited torque can be increased by increasing the elastic force of the coil spring  155 . 
   While not illustrated in  FIG. 12 , teeth are formed around the outer peripheral surface of the pressure plate  154  for engaging with the gear  149 . Hence, the gear  149  rotates together with the rotating pressure plate  154 . The gear  150  is engaged with the gear  149 , and the gear  151  is engaged with the gear  150 . However, the gear  150  and gear  151  are configured of bevel gears with orthogonal axes oriented orthogonal to each other. As shown in  FIG. 11 , the outer peripheral surface of the gear  151  contacts the outer peripheral surface of the rotating plate  125 . In the preferred embodiment, a frictional force is generated through contact between the gear  151  and rotating plate  125  for transmitting torque therebetween. However, it should be apparent that both the gear  151  and rotating plate  125  may be provided with teeth and interlocked to form a gear train. 
   In the preferred embodiment, a rotation restricting device  156  is provided for restricting rotation of the rotating plate  125 . As shown in  FIG. 12 , the rotation restricting device  156  includes the locking member  139  and locking member  140 , a coil spring  157  for elastically urging the locking member  139  to engage with the rotating plate  125 , and a contact member  158  for changing the orientation of the locking member  140 , as will be described later, when contacted by the inkjet recording head  39  sliding in the main scanning direction. 
   The locking member  139  is formed in the shape of a crankshaft. A base end of the locking member  139  is rotatably supported on a support shaft  159 . Accordingly, the locking member  139  can rotate about the support shaft  159  in an elevating direction indicated by the arrow  160 . An engaging pawl  161  is provided on the distal end of the locking member  139 . The engaging pawl  161  is formed in a wedge shape for fitting into the V groove  131  of the rotating plate  125 . 
   Since the locking member  139  can pivot about the support shaft  159 , the orientation of the locking member  139  can be changed between a rotation restricting orientation laying down on the rotating plate  125  side with the engaging pawl  161  fitted into the V groove  131 , and a rotation allowing orientation angled upward above the rotating plate  125  with the engaging pawl  161  removed from the V groove  131 . However, the coil spring  157  is provided for constantly urging the locking member  139  into the rotation restricting orientation. 
   Therefore, when the engaging pawl  161  is fitted into the V groove  131 , the forward restricting surface  132  (see  FIG. 13 ) contacts the engaging pawl  161  when the rotating plate  125  rotates in the forward direction. Therefore the rotating plate  125  is restricted from rotating forward at this time. However, if the rotating plate  125  rotates in reverse while the engaging pawl  161  is fitted into the V groove  131 , the engaging pawl  161  can slide over the reverse allowing surface  133  (see  FIG. 13 ). When the engaging pawl  161  slides over the reverse allowing surface  133 , the locking member  139  shifts into the rotation allowing orientation against the urging force of the coil spring  155 . At this time, the engaging pawl  161  reaches the top surface  137  of the rib  128  and slides over the top surface  137  as the rotating plate  125  rotates. 
   The locking member  140  is formed in the shape of a quadratic prism. While not shown in  FIG. 12 , an engaging pawl is formed on the lower end of the locking member  140 . This pawl is wedge-shaped similar to the engaging pawl  161  of the locking member  139  so as to fit into the V groove  134  provided in the rib  129 . The locking member  140  is also capable of sliding up and down in  FIG. 2 , but a coil spring  162  constantly urges the locking member  140  downward. The engaging pawl provided on the locking member  140  constantly engages with the rotating plate  125  to restrict reverse rotation of the same, but allows forward rotation of the rotating plate  125 . 
   The contact member  158  is coupled to the base end of the locking member  139 . Accordingly, the contact member  158  can rotate about the support shaft  159  together with the locking member  139 . A distal end  164  of the contact member  158  extends upward so that the carriage  38  supporting the inkjet recording head  39  (see  FIG. 5 ) comes into contact with the distal end  164  when sliding in the main scanning direction. Further, the coil spring  157  is coupled to the contact member  158  for elastically urging the contact member  158  together with the locking member  139 , as described above. 
   Next, an overview of the image-recording operation performed with the multifunction device  1  according to the preferred embodiment will be described. 
   In the multifunction device  1  according to the preferred embodiment, the user operates the control panel  4  (see  FIG. 1 ) to select an image-recording format. More specifically, by operating the control panel  4 , the user can select border recording or borderless recording. After the user sets the format through the control panel  4 , the ASIC  70  (see  FIG. 8 ) transmits a signal to the CPU  65  specifying a recording format. Upon receiving this signal, the CPU  65  issues a command to the drive circuit  74  and drive circuit  75  for driving the carriage motor  73  and inkjet recording head  39 . Specifically, when the format is set to borderless recording, the carriage motor  73  is driven so that the carriage  38  (see  FIG. 5 ) is pressed against the contact member  158 . 
     FIG. 15  is a timing chart showing a timing for conveying recording paper and sliding the movable support piece  88  when performing borderless recording. The horizontal axis in  FIG. 15  represents the passage of time. Lines  167  and  173  in  FIG. 15  indicate the positions of the leading edge and trailing edge, respectively, of the conveyed recording paper, while a line  170  indicates displacement of the movable support piece  88 . Lines  169  and  168  indicate displacement of the contact member  158  and the drive timing of the linefeed motor  71 , respectively.  FIGS. 16A-16D  show the sequential displacement of the movable support piece  88  when the recording paper is conveyed. An arrow  166  in  FIG. 16  indicates the paper-conveying direction. Operations shown in  FIG. 16  occur from the moment that the recording paper has been registered by the conveying roller  60  until the recording operation is completed. The operations for conveying the recording paper from the feeding tray  20  to the conveying roller  60  have been omitted. 
   In order to feed recording paper accommodated in the feeding tray  20  to the paper-conveying path  23  for image recording, the controller  64  drives the linefeed motor  71  to rotate the feeding roller  25 . During this feeding operation, the linefeed motor  71  is driven in a reverse rotation. The transmitted drive force from the linefeed motor  71  rotates the feeding roller  25  in a direction for feeding the recording paper, while rotating the conveying roller  60  and discharge rollers  62  in a direction opposite the paper-conveying direction. As the recording paper fed from the feeding tray  20  is conveyed along the paper-conveying path  23 , the recording paper is inverted vertically by the U-shaped paper-conveying path  23 . The leading edge of the recording paper contacts the registration sensor  95  and subsequently contacts the conveying roller  60  and pinch roller. Since the conveying roller  60  is rotating in a direction opposite the paper-conveying direction, the recording paper is registered while the leading edge is in contact with the conveying roller  60  and the pinch roller A point  174  in  FIG. 15  indicates the registration position of the recording paper. After the registration process is completed, the controller  64  drives the linefeed motor  71  to move in a forward rotation. Consequently, the conveying roller  60  and the pinch roller pinch the registered recording paper and convey the paper over the platen  42  as indicated by the line  167 . 
   As the discharge rollers  62  are driven to rotate in the direction opposite the paper-conveying direction by the reverse rotation of the linefeed motor  71 , this rotation is transmitted to the rotating plate  125  via the drive transmitting mechanism  124 . However, rotation of the rotating plate  125  is restricted when the rotating plate  125  is in the initial position, that is, when the locking member  140  is engaged in the V groove  134 . Hence, only the rotating support member  90  is allowed to rotate in reverse by the torque limiter  148  as the reverse rotation of the rotating plate  125  is halted. However, if the rotating plate  125  is not in the initial position and, hence, the locking member  140  is not engaged with the V groove  134 , then the rotation of the discharge rollers  62  is transmitted to the rotating plate  125  via the drive transmitting mechanism  124 , causing the rotating plate  125  to rotate in reverse. Subsequently, the rotating plate  125  rotates in reverse until reaching the initial position, at which time the locking member  140  engages with the V groove  134  and restricts further rotation of the rotating plate  125  in reverse so that only the discharge roller shaft  92  is rotating in reverse. This operation for driving the linefeed motor  71  in reverse is performed to move the rotating plate  125  to the initial position and may be performed when the power to the multifunction device  1  is turned on or after an error is resolved. Further, by moving the rotating plate  125  to the initial position, the locking member  139  engages with the V groove  131  to restrict forward rotation of the rotating plate  125 . 
   During borderless recording, the movable support piece  88  slides along with the conveyance of the recording paper. More specifically, when the recording paper is set in the initial position  174  (see  FIG. 15 ), the movable support piece  88  is positioned in the center of the platen  42 , as shown in  FIG. 16A  At this time, the base end  146  of the lever member  126  is at a prescribed position in the guide groove  143  of the rotating plate  125 , indicated by reference numeral  165  in  FIG. 14 . Reference numeral  165  indicates a position in which a hypothetical axis  172  passing through the center of the cylindrical shaft  127  orthogonal to the hypothetical axis  144  intersects the guide groove  143 . The movable support piece  88 , rotating plate  125 , and lever member  126  are at initial positions relative to each other in  FIG. 16A . 
   After the leading edge of the recording paper is registered by the conveying roller  60 , as described above, the linefeed motor  71  is driven intermittently in a forward rotation for conveying the recording paper to recording positions over the platen  42 , as indicated by the line  168  in  FIG. 15 . Subsequently, the carriage motor  73  is driven at a prescribed timing indicated by the line  169 . The driven carriage motor  73  slides the carriage  38  in the main scanning direction until the carriage  38  contacts the contact member  158  of the rotation restricting device  156 . At this time, the controller  64  regulates the sliding amount of the carriage  38  by controlling the driving of the carriage motor  73 . 
   As shown in  FIG. 12 , when the carriage  38  presses against the contact member  158  in the main scanning direction (ON in  FIG. 15 ), the locking member  139  rotates about the support shaft  159  to the rotation allowing orientation. Therefore, the engaging pawl  161  is disengaged from the rotating plate  125 , enabling the rotating plate  125  to rotate forward (clockwise about the cylindrical shaft  127 ). As described above, when the linefeed motor  71  rotates the discharge roller shaft  92  in the paper-conveying direction, this rotation is transmitted to the rotating plate  125  via the drive transmitting mechanism  124 , driving the rotating plate  125  in a forward rotation. As a result, the movable support piece  88  is displaced, as indicated by the line  170  in  FIG. 15 , and the relative positions of the movable support piece  88 , rotating plate  125 , and lever member  126  change in the sequence shown in  FIG. 16B-16D . Next, the movement of the movable support piece  88  will be described in greater detail. 
   Initially, the movable support piece  88  is positioned at an intermediate between the first fixed ribs  102  and the second fixed ribs  103  (see  FIG. 9 ). However, when the leading edge of the recording paper is conveyed to the upstream end of the frame  100 , the movable support piece  88  moves to the upstream side in the paper-conveying direction to meet the recording paper, as indicated by the line  170  in  FIG. 15 . Specifically, the linefeed motor  71  rotates forward, causing the conveying roller  60  to rotate in the conveying direction and convey the recording paper to the platen  42 . At the same time, the forward rotation of the linefeed motor  71  is transferred to the rotating plate  125 , driving the rotating plate  125  to rotate forward. At this time, the rotating plate  125  rotates in the clockwise direction of  FIGS. 14 and 16 . When the rotating plate  125  rotates forward, the position  165  of the base end  146  of the lever member  126  moves relative to the rotating plate  125  in the direction indicated by the arrow  171  in  FIG. 14 . Hence, the distance between the position  165  of the base end  146  and the cylindrical shaft  127  gradually grows smaller as the rotating plate  125  rotates. Consequently, the lever member  126  pivots about the center part  147 , moving the movable support piece  88  upstream in the conveying direction, as shown in  FIG. 16B . When the rotated angle of the rotating plate  125  reaches 90°, the movable support piece  88  is in a first position between neighboring first fixed ribs  102  for meeting the recording paper. In the preferred embodiment, the movable support piece  88  moves to the first position corresponding to the upstream end in the paper-conveying direction before the leading edge of the recording paper arrives at the upstream end of the platen  42 , as shown in  FIG. 15 . Accordingly, the recording paper covers the top of the ribs  121  on the movable support piece  88 . 
   Subsequently, image recording is performed on the recording paper by repeatedly and alternately ejecting ink droplets from the inkjet recording head  39  while the carriage  38  reciprocates, and conveying the recording paper a prescribed linefeed corresponding to the set resolution. Specifically, the linefeed motor  71  is driven intermittently in a forward rotation, as indicated by the line  168  in  FIG. 15 , thereby intermittently conveying the recording paper by the prescribed linefeed widths. Since the rotating plate  125  rotates in association with the driving of the linefeed motor  71 , the rotating plate  125  rotates intermittently by prescribed angles of rotation in synchronization with the intermittent conveying of the recording paper. The position  165  for the base end  146  of the lever member  126  shifts farther in the direction of the arrow  171  in  FIG. 14  and returns to the initial position when the rotating plate  125  reaches a rotational angle of 360°. Hence, when the rotating plate  125  is at a rotational angle exceeding 90° and no greater than 270°, the distance between the position  165  of the base end  146  and the cylindrical shaft  127  gradually increases as the rotating plate  125  rotates. Hence, as shown in  FIG. 16B-16D , the lever member  126  pivots about the center part  147 , moving the movable support piece  88  downstream in the paper-conveying direction. When the rotational angle of the rotating plate  125  reaches 270°, the movable support piece  88  is in the second position between neighboring second fixed ribs  103 . Hereafter, the distance between the position  165  of the base end  146  and the cylindrical shaft  127  gradually decreases as the rotating plate  125  rotates further. Accordingly, the lever member  126  pivots about the center part  147 , moving the movable support piece  88  toward the upstream side in the paper-conveying direction. When the rotational angle of the rotating plate  125  reaches 360°, the movable support piece  88  has returned to the initial position. 
   When the rotating plate  125  rotates as described above, the engaging pawl  161  slides over the top surface  137  of the rib  128 , as shown in  FIG. 12 . Therefore, when the rotational angle of the rotating plate  125  reaches 360°, the engaging pawl  161  is again fitted into the V groove  131  of the rotating plate  125  (see  FIG. 13 ) due to the urging force of the coil spring  157 , thereby restricting forward rotation of the rotating plate  125 . While the drive transmitting mechanism  124  is halted when forward rotation of the rotating plate  125  is restricted, the torque limiter  148  allows the driving force from the linefeed motor  71  to be transmitted to the conveying roller  60  and the discharge roller shaft  92  so that smooth conveyance of the recording paper is maintained. 
   In this state, the recording paper is conveyed intermittently as prescribed linefeed widths, while recording continues, as shown in  FIG. 15 . Specifically, initially, the movable support piece  88  is halted in the initial position, as indicated by the line  170  in  FIG. 15 , while the trailing edge of the recording paper approaches the upstream end of the platen  42 , as indicated by the line  173 . When the registration sensor  95  detects the trailing edge of the recording paper, the controller  64  controls the driving of the carriage motor  73  based on detection signals from the registration sensor  95  in order that the carriage  38  slides in the main scanning direction and contacts the contact member  158  (ON in  FIG. 15 ), as indicated by the line  169  in  FIG. 15 . 
   When the carriage  38  presses against the contact member  158  in the main scanning direction, the locking member  139  rotates about the support shaft  159  and disengages the engaging pawl  161  from the rotating plate  125 , as described above. Therefore, the rotating plate  125  can move in a forward rotation (clockwise about the cylindrical shaft  127 ). As a result, the movable support piece  88  is displaced as indicated by the line  170  in  FIG. 15 , changing the relative positions of the movable support piece  88 , rotating plate  125 , and lever member  126  in the sequence shown in  FIGS. 16B-16D . In other words, the movable support piece  88  moves intermittently to the first position corresponding to the upstream end in the paper-conveying direction by the intermittent driving of the linefeed motor  71  before the trailing edge of the recording paper arrives at the upstream end of the platen  42 . Here, the ribs  121  of the movable support piece  88  are still covered by the recording paper. Subsequently, the image-recording operation is continued by repeatedly and alternately ejecting ink droplets from the inkjet recording head  39  as the carriage  38  reciprocates, and conveying the recording paper by prescribed linefeed widths corresponding to the set resolution. Since the rotating plate  125  rotates in association with the driving of the linefeed motor  71 , the intermittent driving of the linefeed motor  71  described above causes the rotating plate  125  to rotate intermittently at prescribed angles of rotation in synchronization with the linefeed motor  71 . Accordingly, the rib  121  slides downstream in the paper-conveying direction while supporting the recording paper. 
   After the rotating plate  125  completes one rotation, the engaging pawl  161  is again fitted into the V groove  131  of the rotating plate  125  by the urging force of the coil spring  157 , thereby restricting forward rotation of the rotating plate  125  and returning the movable support piece  88 , rotating plate  125 , and lever member  126  to their initial positions. Once the image-recording operation is completed, the linefeed motor  71  is driven continuously in the forward rotation for discharging the recording paper onto the discharge tray  21 . While the rotation of the rotating plate  125  is restricted at this time, the torque limiter  148  allows the discharge rollers  62  to rotate smoothly. 
   However, if the user sets the image-forming format to border recording by operating the control panel  4 , the carriage  38  is not moved into contact with the contact member  158  Therefore, the movable support piece  88  does not slide as described above, but remains halted in the initial position. When performing border recording, it is still preferable to rotate the linefeed motor  71  in reverse prior to feeding the recording paper In this case, even if the locking member  140  is not engaged with the rotating plate  125 , the rotating plate  125  rotates in reverse as described above until the locking member  140  is fitted into the V groove  134  of the rotating plate  125 , thereby reliably initializing the locking member  140  of the rotating plate  125 . 
   In the multifunction device  1  according to the preferred embodiment, the platen  42  supports the recording paper as the recording paper is conveyed over the platen  42 , and the inkjet recording head  39  records an image on the recording paper by ejecting ink droplets as the carriage  38  slides in the main scanning direction. The recording paper is conveyed in the paper-conveying direction during the image-recording operation, while the movable support piece  88  slides in the paper-conveying direction while supporting the recording paper, as shown in  FIGS. 9 and 15 . 
   As shown in  FIG. 12 , the movable support piece  88  is driven by the rotation of the rotating plate  125 . However, the rotating plate  125  rotates about the cylindrical shaft  127 , and the cylindrical shaft  127  is orthogonal to the top surface  109  of the platen  42 . In other words, the rotating plate  125  rotates in a position parallel to the top surface  109  of the platen  42 . Therefore, the rotating plate  125  is disposed efficiently and compactly near the platen  42 , achieving a compact image-recording unit  24  and facilitating a compact design for the multifunction device  1 . 
   Since the lever member  126  is engaged in the guide groove  143  of the rotating plate  125 , as shown in  FIG. 16 , rotation of the rotating plate  125  moves the distal end  145  of the lever member  126  in the paper-conveying direction between the upstream end and the downstream end of the platen  42 . Hence, the movable support piece  88  slides smoothly together with the recording paper as the recording paper is conveyed so as to constantly support the edge of the recording paper and to prevent the recording paper from bending in the paper-conveying direction. This construction prevents the recording paper from dropping into the groove  116  formed between the first fixed ribs  102  and second fixed ribs  103  in the preferred embodiment. Accordingly, a fixed distance is maintained between the recording paper and the inkjet recording head  39  so that high quality images can be recorded on the paper. 
   Moreover, since the movable support piece  88  is driven by the linefeed motor  71 , the movable support piece  88  can slide more smoothly. Accordingly, images of higher quality can be recorded on the paper. 
   In the preferred embodiment, the movable support piece  88  moves in association with the discharge roller shaft  92 , which is driven by the linefeed motor  71 . In most inkjet recording devices, the conveying roller  60  is disposed near the inkjet recording head  39 , and the drive transmitting mechanism  83  for transmitting a driving force from the conveying roller  60  to the discharge rollers  62 , the purge mechanism  51 , and the like must maintain a prescribed geometrical relationship with the conveying roller  60  and inkjet recording head  39 . Hence, if the movable support piece  88  were to receive a driving force from the conveying roller  60  disposed near the inkjet recording head  39 , the image-recording unit  24  would require a complex structure that would be difficult to design due to the geometrical relationship. However, in the multifunction device  1  according to the preferred embodiment, the movable support piece  88  obtains a drive force from the discharge rollers  62  disposed in a region of the multifunction device  1  having more available space, thereby simplifying the structure of the image-recording unit  24  and enabling a more compact design for the multifunction device  1 . 
   By employing a disc-shaped rotating plate  125  as the means for driving the movable support piece  88  in the preferred embodiment, the structure for driving the movable support piece  88  is extremely simple, and the structure for rotating the rotating plate  125  can be achieved with a compact design. Accordingly, the image-recording unit  24  can be made even more compact. 
   Further, by forming the guide groove  143  in the rotating plate  125  in the shape described above, the movable support piece  88  initially slides upstream in the paper-conveying direction to meet the recording paper and subsequently slides downstream as the recording paper is conveyed, as shown in  FIG. 16 . In this way, the movable support piece  88  constantly supports the edge of the recording paper thereby reliably maintaining a fixed distance between the recording paper and the inkjet recording head  39 . Accordingly, higher quality images can be recorded on the recording paper. 
   Particularly, since the guide groove  143  is shaped like an Archimedean spiral in the preferred embodiment, the distal end  145  of the lever member  126  moves radially from the center of the rotating plate  125  as the rotating plate  125  rotates (see  FIG. 16 ). Specifically, the rotating angle of the rotating plate  125  has a linear relationship with the movement of the distal end  145 , as described above. Therefore, the movable support piece  88  smoothly follows the conveyance of the recording paper at a constant speed in response to the rotating plate  125  rotating at a constant speed, that is, in synchronization with the recording paper that is conveyed intermittently at prescribed linefeed widths. Therefore, the conveying length (linefeed width) of the recording paper is set smaller when recording at a high resolution, for example. In response, the rotating plate  125  rotates intermittently at smaller angles of rotation. The linefeed width of the recording paper is set larger when recording at a low resolution. In response, the rotational angle of the rotating plate  125  is increased greatly to increase the movement of the movable support piece  88  so that the movable support piece  88  more reliably supports the recording paper and more reliably maintains the distance between the recording paper and the inkjet recording head  39 . 
   If the guide groove  143  were not formed in an Archimedean spiral, the rotating plate  125  may rotate at a constant speed unrelated from the linefeed widths of the recording paper. While this configuration does not produce any complications immediately, the constant speed of the rotating plate  125  may cause the movable support piece  88  to pass the conveyed recording paper. If there is a danger of this happening, it is possible to halt the movable support piece  88  at a ratio of once for each prescribed number of linefeeds. 
   As shown in  FIGS. 14 and 16 , the guide groove  143  in the preferred embodiment is formed to follow an Archimedean spiral that is symmetrical about the hypothetical axis  144 . Therefore, the movable support piece  88  can move in one continuous motion, first to slide from the initial position shown in  FIG. 16A  upstream to meet the recording paper, subsequently to slide downstream along with the conveyance of the recording paper while supporting the edge of the recording paper, and finally sliding upstream again to return to the initial position. Therefore, the movable support piece  88  is always reliably disposed in the initial position. In other words, it is not necessary to initialize the movable support piece  88  for each of recording paper when recording on a plurality of sheets continuously, thereby increasing the speed of continuous recording Accordingly, the movable support piece  88  can reliably support the edge of the recording paper and can reliably prevent the recording paper from entering the groove  116 . 
   The multifunction device  1  according to the preferred embodiment also has the following operations and effects. 
   The edge of the recording paper conveyed over the first fixed rib  102  passes above the groove  116 . At this time, the movable support piece  88  slides together with the recording paper as the recording paper is conveyed so as to support the edge of the recording paper at all times and prevent the edge from entering the groove  116 . Accordingly, the movable support piece  88  can maintain a fixed distance between the recording paper and the inkjet recording head  39 . 
   In the preferred embodiment, the recording paper conveyed over the platen  42  is first supported on the first fixed ribs  102 , and subsequently supported on the second fixed ribs  103  after passing over the groove  116 . When performing borderless recording in particular, the groove  116  can receive ink droplets ejected from the inkjet recording head  39  beyond the edge of the recording paper. The bottom of the groove  116  may be lined with an ink absorbing material such as a sheet-like sponge material capable of reliably absorbing ink droplets that reach the groove  116 . 
   As described above, since the recording paper covers the movable support piece  88  when the movable support piece  88  is supporting the edge of the paper, ink droplets ejected onto the recording paper do not become deposited on the movable support piece  88 . Hence, when recording on a plurality of sheets continuously, the bottom surface of subsequent sheets of recording paper do not become stained with ink deposited when recording on the preceding sheets. 
   Further, since the movable support piece  88  supports the recording paper, the groove  116  can be formed with a large width dimension  117 , making it possible to increase the size of the inkjet recording head  39  because the groove  116  can cover the entire ink ejection range  118  of a large inkjet recording head  39 . This construction makes it possible to perform borderless recording at a high speed. 
   The first fixed ribs  102 , second fixed ribs  103 , and ribs  121  functioning to support the recording paper are particularly advantageous because they provide an extremely simple structure for supporting the recording paper and they reduce the area of contact between the support members and the recording paper. Consequently, this construction reduces resistance to the recording paper, enabling the recording paper to be conveyed more smoothly. 
   In the preferred embodiment, the width dimension  117  of the groove  116  (see  FIG. 9 ) is set wider than the ink ejection range  118  of the inkjet recording head  39  (see  FIG. 6 ). With this construction, the groove  116  will receive all ink droplets ejected from the nozzles  53  of the inkjet recording head  39 , even when recording paper is not present on the platen  42 . Hence, when performing borderless recording, the inkjet recording head  39  can eject ink droplets from all nozzles  53  when recording on the edges of the recording paper. Hence, it is not necessary to perform a complex control process for ejecting ink droplets from the nozzles  53  when performing borderless recording, thereby increasing the speed of the recording operation. 
   Put another way, if the width dimension  117  of the groove  116  were narrower than the ink ejection range  118  of the inkjet recording head  39 , then it would be necessary to eject ink droplets only from nozzles  53  on the upstream side of the inkjet recording head  39  when performing borderless recording on the leading edge portion of the recording paper, and subsequently to eject ink droplets from sequential rows of nozzles  53  on the downstream side as the recording paper is conveyed, thereby requiring a complex process for controlling the inkjet recording head  39 . In contrast, the multifunction device  1  of the preferred embodiment can eliminate this complex control process. As described above, the multifunction device  1  can perform borderless recording on the edge of the recording paper by ejecting ink droplets from all nozzles  53 . Hence, borderless recording can be performed at a high speed, without implementing a complex control process for ejecting ink droplets from the nozzles  53 . 
   Further, the cross-sectional shape of the nozzles  53  is not always perfectly round and occasionally fine particles of foreign matter become deposited inside the nozzles  53 . These factors sometimes contribute to an ink droplet trajectory that is less than straight from the nozzles  53 . However, since the width dimension  117  of the groove  116  is set wider than the ink ejection range  118  of the inkjet recording head  39  in the preferred embodiment, the ink droplets do not land outside of the groove  116  even in this case. Hence, this construction reliably prevents ink from staining the underside of recording paper. 
   By using the first fixed ribs  102 , second fixed ribs  103 , and ribs  121  for supporting the recording paper, the structure of the components used to support the recording paper is very simple, and the surface area of contact between the ribs and the recording paper is small. Reducing the surface area of contact with the recording paper reduces the resistance to the recording paper, enabling the recording paper to be conveyed more smoothly. Further, sloped surfaces are formed on the corner  122  and corner  123  of the ribs  121  through a process of beveling the corner  122  and corner  123 . Hence, when the edge of the recording paper passing over the first fixed ribs  102  contacts the corners  122  of the ribs  121 , the edge of the recording paper is guided smoothly onto the movable support piece  88 . Hence, the movable support piece  88  does not interfere with the smooth conveyance of the recording paper. As described above, the bevel process is also performed on the corners of the first fixed ribs  102  and second fixed ribs  103 , forming sloped surfaces in these areas. Hence, when the edge of a sheet of recording paper contacts the corners of the first fixed ribs  102  and second fixed ribs  103 , the sloped surfaces facilitate the smooth conveyance of the recording paper. 
   As shown in  FIG. 16 , the lever member  126  engaged with the rotating plate  125  converts the rotation of the rotating plate  125  into displacement of the movable support piece  88  in the conveying direction by a prescribed ratio. Accordingly, the movable support piece  88  can slide in synchronization with the conveyance of the recording paper. At the same time, the rotational amount of the rotating plate  125  is amplified as displacement in the conveying direction, making it possible to reduce the size of the rotating plate  125  and design a more compact multifunction device  1 . 
   In the preferred embodiment, the locking member  139  is normally engaged with the rotating plate  125 , as shown in  FIG. 12 . Therefore, unless borderless recording is performed, the movable support piece  88  does not slide along with the recording paper. At this time, the movable support piece  88  is disposed between the first fixed ribs  102  and second fixed ribs  103  and helps prevent the recording paper conveyed over the platen  42  from entering the groove  116 . The locking member  139  may also be separated from the rotating plate  125  when performing borderless recording. Hence, the setting for borderless recording or border recording may be freely modified by moving the locking member  139 . 
   Next, a variation of the preferred embodiment will be described. 
     FIG. 17  is an enlarged perspective view of the platen  42  and movable support piece  176  in the multifunction device  1  according to a variation of the preferred embodiment. 
   In the preferred embodiment described above, the movable support piece  88  is provided with the lever member  126 , as shown in  FIG. 11 , for coupling the movable support piece  88  to the rotating plate  125 . However, the movable support piece  176  of the variation is provided with an engaging pin  175  that is fitted into the guide groove  143  of the rotating plate  125 . For this reason, the cylindrical shaft  127  of the rotating plate  125  extends along the main scanning direction, indicated by the arrow  87 , requiring a modification in the geometry of the drive transmitting mechanism  124  that includes the gear  151  for driving the rotating plate  125 . The remaining structure of the movable support piece  176  is identical to the movable support piece  88  in the preferred embodiment. 
   More specifically, an engaging surface  142  (“back surface” in the preferred embodiment) of the rotating plate  125  is substantially orthogonal to the top surface  109  of the platen  42 . The engaging pin  175  protrudes from an end surface of the movable support piece  176  and fits into the guide groove  143  formed in the engaging surface  142  of the rotating plate  125 . The engaging pin  175  is capable of sliding within the guide groove  143 . Hence, rotation of the rotating plate  125  slides the movable support piece  176  via the engaging pin  175  in the variation of the embodiment so that the ribs  121  can reliably support recording paper conveyed over the platen  42 . Moreover, since the movable support piece  176  is slid via the engaging pin  175 , the interlock mechanism  105  functioning to drive the movable support piece  176  can be achieved with a simple structure. 
   Second Embodiment 
   Next, a second embodiment of the present invention will be described. 
     FIG. 18  is an enlarged perspective view of the platen  42  in the multifunction device  1  according to a second embodiment of the present invention.  FIG. 19  is a front view of the platen  42 .  FIGS. 20 and 21  are views of the platen  42  indicated by the arrows XX and XXI, respectively, in  FIG. 19 .  FIG. 22  is a perspective view from the bottom surface of the platen  42 .  FIG. 23  is a bottom view of the platen  42 . Next, the structures of the platen  42 , movable support piece  88 , and interlock mechanism  105  according to the second embodiment will be described in detail. Except for these components, the structure of the multifunction device  1  in the following description is identical to that in the first embodiment. 
   As in the first embodiment described above, the platen  42  in the second embodiment is disposed opposite the inkjet recording head  39  (below the inkjet recording head  39  in  FIG. 3 ) for supporting recording paper during a recording operation (see  FIGS. 3 and 5 ). As shown in  FIG. 18 , the platen  42  has an overall rectangular plate shape that is thin and narrow, with the longitudinal dimension of the platen  42  extending in the main scanning direction. The arrow  101  in  FIG. 18  indicates the paper-conveying direction. 
   The platen  42  includes the frame  100 ; the first fixed ribs  102  and second fixed ribs  103  disposed on the frame  100 ; the movable support piece  88  slidably provided on the frame  100 ; and the interlock mechanism  105  for sliding the movable support piece  88 . 
   The frame  100  is formed of a synthetic resin or steel plate, for example, and constitutes the frame of the platen  42 . The cross-section of the frame  100  is shaped similar to the letter C. The bracket  106  and bracket  107  are disposed one on the base end and distal end of the frame  100 . The bracket  106  and bracket  107  are integrally formed with the frame  100 . The frame  100  is fixed to the multifunction device  1  via the bracket  106  and bracket  107 . 
   The drive mechanism mounting section  108  is disposed on the base end of the frame  100 . As shown in  FIGS. 18 and 22 , the drive mechanism mounting section  108  includes an upper plate  177  extending from the top surface  109  side of the frame  100 , and a lower plate  178  provided on the lower surface side of the frame  100 . The upper plate  177  and lower plate  178  are both rectangular in shape and are formed integrally with the frame  100 . The lower plate  178  supports the interlock mechanism  105  described later in greater detail. 
   The first fixed ribs  102  and second fixed ribs  103  are provided on the top surface  109  of the frame  100 . More specifically, the first fixed ribs  102  are provided on an upstream end of the top surface  109  in the paper-conveying direction and protrude upward toward the inkjet recording head  39 . Similarly, the second fixed ribs  103  are provided on the downstream side of the top surface  109  and protrude upward. As shown in  FIG. 18 , the first fixed ribs  102  and second fixed ribs  103  in the preferred embodiment are thin, rectangular plate-shaped members erected from the top surface  109 . 
   In the preferred embodiment, the first fixed ribs  102  are provided on the top surface  109  and juxtaposed in the main scanning direction. Similarly, the second fixed ribs  103  are provided on the top surface  109  and juxtaposed in the main scanning direction. With this construction, the groove  116  is formed between the first fixed ribs  102  and second fixed ribs  103 . As shown in  FIGS. 18 and 19 , the groove  116  extends in the main scanning direction and expands in the paper-conveying direction. The groove  116  has a width dimension  117  that corresponds to the size of the inkjet recording head  39 . Specifically, the width dimension  117  of the groove  116  is set wider than the ink ejection range  118  (see  FIG. 6 ) of the inkjet recording head  39 . 
   As shown in  FIG. 19 , each of the first fixed ribs  102  opposes one of the second fixed ribs  103  across the groove  116  in the paper-conveying direction indicated by the arrow  101 . As shown in  FIG. 18 , corners  112  and  113  of the first fixed rib  102  are beveled to form a pair of sloped surfaces. In the preferred embodiment, sloped surfaces are formed on both the  112  and  113  of the first fixed rib  102  in the paper-conveying direction. However, it is also possible to form a sloped surface in only the corner  112 . Similarly, corners  114  and  115  of the second fixed ribs  103  are beveled to form a pair of sloped surfaces. In the preferred embodiment, sloped surfaces are formed on both the corners  114  and  115  of the second fixed rib  103  in the paper-conveying direction. However, it is also possible to form a sloped surface in only the corner  114  on the upstream side. 
   A plurality of slits  119  is formed on the top surface  109  of the frame  100 . As shown in  FIG. 18 , the slits  119  extend from the upstream end to the downstream end of the top surface  109  in the paper-conveying direction. Each slit  119  extends from the region between neighboring first fixed ribs  102  to the region between neighboring second fixed ribs  103 . The movable support piece  88  is fitted into the slit  119  from below and protrudes upward from the slits  119 . 
   As shown in  FIG. 22 , the movable support piece  88  includes the base  120  formed in a box shape, and the ribs  121  configured of thin, rectangular plate-shaped members. The movable support piece  88  is configured of a synthetic resin or metal. The base  120  is configured of a member having a C-shaped cross-section that fits inside the frame  100 . While not shown in  FIG. 22 , both ends of the base  120  in the main scanning direction are slidably supported by the frame  100 . Hence, the base  120  can slide smoothly inside the frame  100  in the paper-conveying direction indicated by the arrow  101  in  FIG. 23 . 
   The ribs  121  are provided on the top surface of the base  120  and are formed integrally with the same. Each of the ribs  121  is formed in a rectangular shape and protrudes upward from the top surface  109  of the frame  100  through the slits  119 , as shown in  FIG. 18 . A plurality of the ribs  121  are provided on the top surface of the base  120 . As shown in  FIG. 22 , the ribs  121  are juxtaposed at prescribed intervals in the main scanning direction. The prescribed intervals correspond to the pitch of the slits  119 . Hence, the ribs  121  pass through and protrude upward from the slits  119 . 
   A beveling process similar to that performed on the first fixed ribs  102  and second fixed ribs  103  is performed on the corners  122  and  123  of the ribs  121 , forming a pair of sloped surfaces on each rib  121 . In the preferred embodiment, the sloped surfaces are formed on both of the corner  122  and corner  123  of each rib  121 . However, it is possible to form the sloped surface on only the upstream corner  122 . 
   As described above, the interlock mechanism  105  slides the movable support piece  88  in the paper-conveying direction. As shown in  FIG. 22 , the interlock mechanism  105  includes an input member  224 , a rotating plate  225 , and a pivoting member  226 . In the preferred embodiment, the interlock mechanism  105  also includes a rotation-restricting member  227  for restricting rotation of the rotating plate  225 , as will be described later, and a spring member (not shown). The spring member is configured of a spiral spring, for example, and is disposed between the upper plate  177  and lower plate  178 . The spring member is fixed to either the upper plate  177  or the lower plate  178  and the rotating plate  225  and changes shape as the rotating plate  225  rotates. Hence, when the rotating plate  225  rotates as will be described later, the spring member stores strain energy corresponding to the rotational angle of the rotating plate  225 . When this strain energy is released from the cylindrical shaft  127 , the rotating plate  225  is rotated in the reverse direction. 
   The input member  224  is substantially L-shaped, as shown in  FIG. 22 , and includes a first arm  229  and a second arm  230 . The input member  224  is disposed outside the printing region in the main scanning direction and is retained in this position by a holding part  228  disposed on the bottom surface of the lower plate  178 . The holding part  228  is cylindrical with a rectangular cross-section. The first arm  229  of the input member  224  is slidably inserted into the holding part  228 . As shown in  FIGS. 22 and 23 , an engaging pawl  231  is formed on an end of the first arm  229 , while a restriction release arm  232  is formed on the base end side (the second arm  230  side) of the engaging pawl  231 . The restriction release arm  232  releases the rotational restriction on the rotating plate  225 , as will be described later. The second arm  230  is formed continuously from the base end of the first arm  229  and extends orthogonal to the first arm  229 . In other words, as shown in  FIG. 22 , the second arm  230  extends a prescribed distance above the upper plate  177  of the drive mechanism mounting section  108 . Hence, the carriage  38  supporting the inkjet recording head  39  presses against the second arm  230  when sliding in the direction of the arrow  233  (main scanning direction). Although not shown in  FIG. 22 , a spring is disposed inside the holding part  228  for elastically urging the input member  224  in the direction opposite the arrow  233 . Therefore, if the carriage  38  separates from the input member  224  after pressing against the input member  224  in the direction of the arrow  233 , the spring urges the input member  224  to slide in the direction opposite the arrow  233 . 
   The rotating plate  225  is disc-shaped and capable of rotating on a rotational shaft  234 . The rotational shaft  234  is fixed to the frame  100  (more specifically, the lower plate  178 ) and inserted through the center of the rotating plate  225 . A plurality of teeth  235  is formed continuously around the periphery of the rotating plate  225 . The teeth  235  engage with the engaging pawl  231  of the input member  224 . Hence, when the input member  224  is slid in the direction of the arrow  233 , as described above, the rotating plate  225  rotates clockwise in  FIG. 23  about the rotational shaft  234 . Further, since the input member  224  is elastically urged in a direction opposite the arrow  233 , as described above, the input member  224  slides in the direction opposite the arrow  233  after the carriage  38  presses the input member  224  in the direction of the arrow  233  and subsequently separates therefrom. Hence, the engaging pawl  231  once again engages with the teeth  235 . Further, as shown in  FIGS. 22 and 23 , the guide groove  143  is formed in the rotating plate  225 . The guide groove  143  describes an Archimedean spiral, identical to the shape of the guide groove  143  formed in the rotating plate  125  of the first embodiment. A base end of the pivoting member  226  is engaged in the guide groove  143 . 
   The pivoting member  226  includes a main body  237  configured of a long slender plate, an engaging pin  238  disposed on the base end  146  of the main body  237 , and an engaging rod  239  disposed on the distal end  145  of the main body  237 . The pivoting member  226  is configured of a synthetic resin or metal. The main body  237  is rotatably supported on a pivot shaft  240 . The pivot shaft  240  is fixed to the lower plate  178  of the drive mechanism mounting section  108  and inserted through a center portion of the main body  237 . The engaging pin  238  protrudes upward from the main body  237  (see  FIG. 22 ) and fits into the guide groove  143  of the rotating plate  225 . The outer diameter of the engaging pin  238  corresponds to the width of the guide groove  143  so that the engaging pin  238  can slide relative to the rotating plate  225  along the guide groove  143  without play. When the engaging pin  238  moves relative to the rotating plate  225  along the guide groove  143 , the main body  237  rotates about the pivot shaft  240 . Hence, the pivoting member  226  pivots around the pivot shaft  240  so that the engaging rod  239  disposed on the distal end  145  of the main body  237  slides in an arc about the pivot shaft  240  The engaging rod  239  is coupled to the base  120  of the movable support piece  88 . An elongated hole  241  extending in the longitudinal direction (main scanning direction) is formed in the base  120 . The engaging rod  239  is fitted into the elongated hole  241 . The outer diameter of the engaging rod  239  corresponds to the inner diameter of the elongated hole  241  so there is no play between the base  120  and elongated hole  241  other than in the main scanning direction. 
   Therefore, when the main body  237  pivots as described above so that the engaging rod  239  moves in an arc about the pivot shaft  240 , the base  120  slides in the conveying direction as the engaging rod  239  slides along the elongated hole  241  in the main scanning direction. As described above, both ends of the base  120  in the main scanning direction are slidably supported on the frame  100 . Accordingly, the base  120  slides smoothly in the paper-conveying direction (indicated the arrow  101  in  FIG. 23 ) along a plane in the frame  100  parallel to the top surface  109 . Hence, the pivoting member  226  slides the movable support piece  88  in the paper-conveying direction. 
   The rotation-restricting member  227  employs an engaging rod for engaging with the rotating plate  225 . As shown in  FIG. 23 , the rotation-restricting member  227  is rotatably supported by a support pin  242 . The support pin  242  is erected from the lower plate  178  of the drive mechanism mounting section  108  and inserted into the base end of the rotation-restricting member  227 . An engaging pawl  243  is formed on the distal end of the rotation-restricting member  227  and engages with the teeth  235  on the rotating plate  225 . Consequently, the rotating plate  225  is allowed to rotate clockwise in  FIG. 23 , but restricted from rotating counterclockwise. A spring  244  elastically urges the rotation-restricting member  227  toward the rotating plate  225 . Therefore, the rotation-restricting member  227  is engaged with the rotating plate  225  at all times for restricting rotation of the same. 
   The rotation-restricting member  227  is also provided with a contact pin  245 . The contact pin  245  protrudes downward from the rotation-restricting member  227  (see  FIG. 22 ). As described above, the input member  224  is slid in the direction of the arrow  233 . However, when the input member  224  is slid to a prescribed restriction release position, the restriction release arm  232  contacts the contact pin  245  and presses the  245  in the direction of the arrow  233 . The pressure on the contact pin  245  rotates the rotation-restricting member  227  against the elastic force of the spring  244 , disengaging the engaging pawl  243  from the rotating plate  225  and releasing the rotational restriction on the rotating plate  225 . 
   In the preferred embodiment, the engaging pin  238  is engaged with the guide groove  143  at a prescribed position in  FIG. 23  (initial position). At this time, the movable support piece  88  is positioned in the center of the frame  100  between the first fixed ribs  102  and second fixed ribs  103 , as shown in  FIG. 18 . As described in the first embodiment, the movable support piece  88  is normally disposed in this position. 
   When the inkjet recording head  39  reciprocates in the main scanning direction, the carriage  38  intermittently presses against the input member  224 , causing the rotating plate  125  to rotate clockwise in  FIG. 23  intermittently at prescribed angles of rotation (corresponding to the rotational feed amount of the teeth  235 ). When the rotating plate  225  rotates in this way, the guide groove  143  pivots about the rotational shaft  234  and, hence, the engaging pin  238  engaged in the guide groove  143  moves toward the left along with the rotation of the rotating plate  225 . When the rotational angle of the rotating plate  225  reaches 90°, the engaging pin  238  begins to move toward the right along with the rotation of the rotating plate  225  and continues moving right until the rotational angle of the rotating plate  225  reaches 270°. 
     FIGS. 24 and 25  are explanatory diagrams showing the relationship between the conveyance of the recording paper and the movement of the movable support piece  88 . 
   The movable support piece  88  is initially positioned between the first fixed ribs  102  and second fixed ribs  103 . However, when a sheet of recording paper  246  is conveyed to the upstream edge  94  of the frame  100 , as shown in  FIG. 24A , the movable support piece  88  moves upstream in the paper-conveying direction to meet the recording paper  246 . Specifically, when a sheet of the recording paper  246  fed along the paper-conveying path  23  (see  FIG. 3 ) reaches the conveying roller  60 , the conveying roller  60  conveys the sheet over the platen  42 . 
   As described in the first embodiment, to perform an image-recording operation the controller  64  drives the linefeed motor  71  in order to rotate the feeding roller  25 . The feeding roller  25  feeds a sheet of recording paper stacked in the feeding tray  20  onto the paper-conveying path  23 . When feeding a sheet of recording paper, the linefeed motor  71  is driven in a reverse rotation. The drive force of the linefeed motor  71  is transferred to the feeding roller  25  and rotates the feeding roller  25  in a direction for feeding the recording paper. The driving force is also transferred to the conveying roller  60  and discharge rollers  62  for rotating the conveying roller  60  and discharge rollers  62  in the direction opposite the paper-conveying direction. Recording paper conveyed from the feeding tray  20  along the paper-conveying path  23  is guided by the paper-conveying path  23  along a U-shaped path that curves upward and back in the opposite direction. As the recording paper is conveyed farther, the leading edge of the paper first contacts the registration sensor  95  and subsequently contacts the conveying roller  60  and the pinch roller. Since the conveying roller  60  is rotating in a direction opposite the paper-conveying direction, the recording paper is registered by contacting the conveying roller  60  and the pinch roller. The registration position is indicated by the reference numeral  174  in  FIG. 15 . After recording paper has been registered, the controller  64  begins driving the linefeed motor  71  to rotate forward. Consequently, the registered recording paper is pinched between the conveying roller  60  and the pinch roller and conveyed over the platen  42  as indicated by the line  167  in  FIG. 15 . 
   When performing borderless recording, the movable support piece  88  is slid along with the conveyance of the recording paper. More specifically, when the recording paper is at the registration position  174 , the movable support piece  88  is positioned in the center of the platen  42 , as described above. At this time, the base end  146  of the pivoting member  226  is disposed in a prescribed position of the guide groove  143  (an initial position similar to the position indicated by the reference numeral  165  in  FIG. 14 ), as shown in  FIG. 23 . 
   After the leading edge of the recording paper  246  has been registered on the conveying roller  60 , the linefeed motor  71  is driven intermittently, as indicated by the line  168  in  FIG. 15 , conveying the recording paper  246  to a recording position on the platen  42 . Subsequently, the carriage motor  73  is driven at a prescribed timing indicated by the line  169  in  FIG. 15  for slidingly moving the carriage  38  in the main scanning direction until the carriage  38  contacts the input member  224 . Here, the controller  64  controls the amount that the carriage  38  is slid by driving the carriage motor  73 . 
   When the carriage  38  slides against the input member  224 , the rotating plate  225  rotates clockwise in  FIG. 23 , moving the movable support piece  88  upstream in the paper-conveying direction, as shown in  FIG. 24A . When the rotational angle of the rotating plate  225  reaches 90°, the movable support piece  88  has arrived at the first position for meeting the recording paper  246 . 
   Thereafter, each time the carriage  38  slides into the input member  224  during the image-recording operation, the rotating plate  225  is rotated clockwise in  FIG. 23 . As the rotating plate  225  rotates progressively clockwise, the movable support piece  88  moves downstream in the paper-conveying direction along with the recording paper  246 , while supporting the leading edge of the recording paper  246 , as shown in  FIG. 24B . When the rotational angle of the rotating plate  125  reaches 180°, the  121  have moved from the first position to the initial position (center of the groove  116 ), as shown in  FIG. 24C . 
   After the rotational angle of the rotating plate  125  has reached 180° and the movable support piece  88  has moved between the first fixed ribs  102  and second fixed ribs  103 , the movable support piece  88  is maintained in this position while the recording paper  246  continues to be conveyed in the paper-conveying direction and the image-recording operation continues to be performed, as shown in  FIG. 25A . In this way, the sliding distance of the inkjet recording head should be controlled so that the carriage  38  does not contact the input member  224  as a means for maintaining the movable support piece  88  while the recording paper  246  is conveyed. 
   When the recording paper  246  has been conveyed far enough for the trailing edge to reach the movable support piece  88 , as shown in  FIG. 25B , the movable support piece  88  is again slid in the paper-conveying direction so as to move downstream along with the recording paper  246  while supporting the trailing edge of the recording paper  246 , as shown in  FIG. 25C . More specifically, the carriage  38  is again slid against the input member  224 , causing the rotating plate  225  to rotate clockwise in  FIG. 23  and, hence, moving the movable support piece  88  further downstream in the paper-conveying direction. When the rotational angle of the rotating plate  225  reaches 270°, the movable support piece  88  has arrived at the second position. Subsequently, the sliding distance of the inkjet recording head  39  should be controlled so that the carriage  38  again contacts the input member  224  as a means for resuming movement of the movable support piece  88  halted between the first fixed ribs  102  and second fixed ribs  103  (initial position). 
   When the recording paper  246  is discharged, the carriage  38  slides the input member  224  to a prescribed restriction release position. Here, the carriage motor is driven to slide the carriage  38  to a prescribed position for moving the input member  224  to the restriction release position. More specifically, the input member  224  is slid in the direction of the arrow  233  shown in  FIG. 23  until the restriction release arm  232  presses against the support pin  242  This pressure causes the rotation-restricting member  227  to rotate counterclockwise against the elastic force of the spring  244 , releasing the rotational restriction on the rotating plate  225 . Since strain energy is stored in the spring member when the rotating plate  225  rotates, this strain energy is released when the rotational restriction on the rotating plate  225  is released, causing the rotating plate  225  to rotate in reverse (counterclockwise in  FIG. 23 ). When all of the strain energy is released, the rotating plate  225  rotates counterclockwise 270°, thereby returning the movable support piece  88  to the initial position. 
   In the multifunction device  1  of the preferred embodiment, the platen  42  supports the recording paper  246  as the recording paper  246  is conveyed over the top thereof, and an image is recorded on the recording paper  246  supported on the platen  42  with ink droplets ejected from the inkjet recording head  39  as the inkjet recording head  39  reciprocates. As the recording paper  246  is conveyed in the paper-conveying direction during the image-recording operation, the movable support piece  88  slides together with the recording paper  246  in the same direction while supporting the recording paper  246 , as shown in  FIGS. 24 and 25 . Therefore, the movable support piece  88  constantly supports the edge of the recording paper  246  during the image-recording operation, preventing the edge from bending in the paper-conveying direction. Accordingly, the recording paper  246  does not droop down into the groove  116  formed between the first fixed ribs  102  and second fixed ribs  103  in the preferred embodiment (see  FIGS. 18 and 19 ), and a fixed distance is maintained between the recording paper  246  and the inkjet recording head  39 . As a result, the multifunction device  1  can perform high-quality printing, as in the first embodiment. 
   More specifically, the recording paper  246  is conveyed over the platen  42  while first supported by the first fixed ribs  102  and subsequently supported by the second fixed ribs  103  after passing over the groove  116 . During borderless recording, the groove  116  can receive ink droplets ejected from the inkjet recording head  39  beyond the edges of the recording paper  246 , thereby preventing such ink droplets from becoming deposited on the underside of subsequent sheets of the recording paper  246 . As the recording paper  246  is conveyed over the groove  116 , the movable support piece  88  slides in the paper-conveying direction along with the conveyance of the recording paper  246 . In other words, the movable support piece  88  supports the recording paper  246  while sliding from the first position to the second position. Hence, the movable support piece  88  reliably supports the edges of the recording paper  246  at all times, preventing the recording paper  246  from entering the groove  116 . As a result, the movable support piece  88  maintains a fixed distance between the recording paper  246  and the inkjet recording head  39 , as described above, thereby achieving high-quality printing. 
   As shown in  FIG. 22 , the movable support piece  88  is driven by the rotation of the rotating plate  225  while the rotating plate  225  rotates about the rotational shaft  234 . Hence, the rotating plate  225  in the preferred embodiment rotates within a plane parallel to the top surface  109  of the platen  42 . Hence, the rotating plate  225  is disposed efficiently and compactly near the platen  42 , making it possible to reduce the size of the image-recording unit  24  and design a more compact multifunction device  1 . 
   In the preferred embodiment, the rotation-restricting member  227  functions to restrict rotation of the rotating plate  225 . As shown in  FIGS. 22 and 23 , the input member  224  and rotation-restricting member  227  configure a ratchet structure that allows only clockwise rotation of the rotating plate  225  in  FIG. 23 . Accordingly, the rotating plate  225  rotates clockwise each time the inkjet recording head  39  reciprocates, enabling the movable support piece  88  to slide reliably in the paper-conveying direction for supporting the recording paper  246 . Here, the controller  64  may control movement of the inkjet recording head  39  so that the carriage  38  presses against the input member  224  each time the inkjet recording head  39  reciprocates, or may adjust the rotation of the rotating plate  225  by having the carriage  38  press against the input member  224  every prescribed number of times the inkjet recording head  39  reciprocates. Controlling movement of the inkjet recording head  39  in this way, the controller  64  can synchronize the distance that the movable support piece  88  slides with the linefeed width of the recording paper  246 . 
   By forming the guide groove  143  having the shape described above in the rotating plate  225  and rotating the rotating plate  225 , the movable support piece  88  initially slides in the paper-conveying direction to meet the recording paper  246  and subsequently slides downstream together with the recording paper  246 , as illustrated in  FIGS. 24 and 25 . With this method, the movable support piece constantly supports the edge of the recording paper  246 , thereby reliably maintaining a fixed distance between the recording paper  246  and the inkjet recording head  39 . Hence, images of a higher quality can be recorded on the recording paper  246 . 
   By forming the guide groove  143  in the shape of an Archimedean spiral in the preferred embodiment, the movable support piece  88  smoothly follows the conveyed recording paper  246  at a fixed speed as the rotating plate  225  rotates at a fixed speed. If the intermittent rotation of the rotating plate  225  corresponds to the linefeed width of the recording paper  246 , the movable support piece  88  slides in synchronization with the conveyance of the recording paper  246 , providing more reliable support for the recording paper  246 . Accordingly, the movable support piece  88  can more accurately maintain a fixed distance between the inkjet recording head  39  and the recording paper  246 . 
   In the preferred embodiment, a spring member is disposed between the upper plate  177  and lower plate  178 . The spring member deforms as the rotating plate  225  rotates and stores a strain energy corresponding to the rotational angle of the rotating plate  225 . After the recording paper  246  is discharged, the controller  64  controls the sliding movement of the inkjet recording head  39  so that the carriage  38  presses the input member  224  into the restriction release position, releasing the rotational restriction on the rotating plate  225 . Consequently, the strain energy stored in the spring member is released, causing the rotating plate  225  to rotate counterclockwise until the movable support piece  88  returns to the initial position shown in  FIG. 18 . Therefore, the movable support piece  88  returns to the initial position after the recording paper  246  is discharged, eliminating the need to initialize the movable support piece  88  for each sheet of recording paper  246 . Accordingly, the multifunction device  1  of the preferred embodiment can perform continuous recording on a plurality of sheets of recording paper  246  at a high speed. 
   As shown in  FIGS. 22 and 23 , since the guide groove  143  formed like an Archimedean spiral is also circular in shape in the preferred embodiment, the movable support piece  88  slides in one continuous motion, initially sliding from the initial position upstream in the paper-conveying direction to meet the recording paper  246 , then continuing downstream as the recording paper  246  is conveyed while supporting an edge of the recording paper  246 , and finally continuing back upstream to the initial position. Therefore, even if the spring member were omitted, the movable support piece  88  would always reliably be returned to the initial position, eliminating the need to initialize the movable support piece  88  for each sheet of the recording paper  246 . Accordingly, the multifunction device  1  of the preferred embodiment can perform continuous recording on a plurality of sheets of the recording paper  246  at a high speed. 
   By supporting the recording paper  246  with the movable support piece  88  in the preferred embodiment, the groove  116  may be formed with a large width dimension  117 . Therefore, even if the size of the inkjet recording head  39  were increased, the groove  116  can cover the entire ink ejection range  118  of the inkjet recording head  39 . As a result, borderless recording can be executed at a higher speed. It is particularly advantageous to configure the parts supporting the recording paper  246  with ribs since the structure is extremely simple. Further, the area of contact between the recording paper  246  and the first fixed ribs  102 , second fixed ribs  103 , and movable support piece  88  (ribs  121 ) is reduced, facilitating the smooth conveyance of the recording paper  246 . 
   As in the first embodiment, the groove  116  according to the second embodiment has a wider width dimension  117  than the ink ejection range  118  of the inkjet recording head  39 . Hence, even if ink droplets were ejected from all nozzles  53  in the inkjet recording head  39  when the recording paper  246  is not present over the platen  42 , the groove  116  can receive all of the ink droplets. Therefore, when performing borderless recording, ink droplets can be ejected from all the nozzles  53  in the inkjet recording head  39  when recording on the edges of the recording paper  246 . Hence, borderless recording can be performed at a high speed, since there is no need to perform a complex control process to control ink droplet ejection. Further, the cross-sectional shape of the nozzles  53  is not always perfectly round and occasionally fine foreign matter may become deposited inside the nozzles  53 , causing the ink droplets to be ejected along a slightly slanted trajectory from the nozzles  53 . However, the ink droplets do not impact the platen  42  outside the groove  116  since the width dimension  117  of the groove  116  is wider than the ink ejection range  118  of the inkjet recording head  39 , thereby reliably preventing ink from staining the underside surface of the recording paper  246 . 
   Further, sloped surfaces are formed on the ribs  121  by beveling the corners  122  and  123  thereof (see  FIG. 18 ). Consequently, the leading edge of the recording paper  246  is smoothly guided onto the top surface of the movable support piece  88  when contacting the corner  122  of the movable support piece  88 . Hence, the movable support piece  88  can be provided without interfering with the smooth conveyance of the recording paper  246 . Similarly, sloped surfaces are formed on the first and second fixed ribs  102  and  103  by beveling the corners  112 - 115  thereof. Accordingly, the fixed ribs  102  and  103  do not interfere with the smooth conveyance of the recording paper  246  when the recording paper  246  contacts the corners  112 - 115 . 
   In particular, the carriage motor  73  drives the carriage  38  to slide in a reciprocating motion so as to contact and slide the input member  224  (see  FIGS. 22 and 23 ). The rotating plate  225  rotates each time the input member  224  slides, while the pivoting member  226  converts the rotation of the rotating plate  225  into sliding displacement of the movable support piece  88 . Therefore, the interlock mechanism  105  does not interfere with the operation for reliably conveying the recording paper  246 , since the linefeed motor  71  is not directly the drive source of the movable support piece  88 . While the carriage motor  73  functions as the drive source of the movable support piece  88  in the preferred embodiment, the carriage motor  73  controls the carriage  38  to press against the input member  224  in a region outside the scanning range of the carriage  38  (that is, an area outside the image-recording range), thereby ensuring that the recording paper  246  is conveyed accurately within the image-recording range. 
   The movement of the movable support piece  88  described above is particularly necessary when performing borderless recording on the recording paper  246  and is not necessary when performing border recording. Since the movable support piece  88  is normally idle in the position shown in  FIG. 18 , it is possible to fix the movable support piece  88  in the position shown in  FIG. 18  and to not drive the movable support piece  88  when performing border recording. In this case, the controller  64  may adjust the distance that the inkjet recording head  39  moves as a means for fixing the movable support piece  88 . In other words, the controller  64  may drive the carriage motor  73  so that the carriage  38  does not contact the input member  224 .