Patent Publication Number: US-7896489-B2

Title: Image recording apparatus

Description:
The entire contents of literatures cited in this specification are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     The present invention belongs to the technical field of an image recording apparatus such as an ink jet printer. In particular, the present invention relates to an image recording apparatus capable of achieving high productivity by transporting recording media in parallel as needed and capable of easily performing switching between parallel transport and single-line transport. 
     As a method of achieving an enhancement in productivity in various types of image recording apparatus including an ink jet printer, there is known a method in which recording media are transported in a plurality of lines arranged in a direction (hereinafter referred to as the width direction) perpendicular to a recording medium transporting direction (hereinafter referred to as the parallel transport) and in which image recording (drawing) and a post-processing after image recording are performed in this parallel transport state. 
     It goes without saying that to output proper prints, the recording media must be positioned properly in the width direction at the time of image recording, etc. 
     For this purpose, there have been proposed various regulating guides for regulating positions of the recording media in the width direction in conformity with the image recording apparatus in which the image recording is to be performed through the parallel transport. 
     For example, JP 2003-260839 A (hereinafter referred to as Patent Document 1) discloses an image recording apparatus having a regulating guide composed of a fixed guide which has at either end in the width direction a groove for regulating a position of one end (i.e., end in the width direction) of a recording medium and which is fixed to a support plate so as to be situated at the center in the width direction, and two movable guides each of which has a groove for regulating a position of the other end of a recording medium on the inner side in the width direction and which are situated at both sides in the width direction of the fixed guide and movable in the width direction. The regulating guide has the pair of movable guides situated at both sides in the width direction of the fixed guide as two movable guides, and a plurality of mounting portions for mounting the movable guides are arranged side by side in the width direction on the support plate, so that the movable guides are detachable in the width direction. 
     With this regulating guide, the distance between the movable guides (their positions in the width direction) is adjusted, whereby it is possible to perform the parallel transport of recording media while properly regulating their positions in the width direction in conformity with recording media of various sizes (widths). However, in the image recording apparatus using this regulating guide, it is impossible to perform the image recording through the single-line transport in which the recording media are not arranged in a plurality of lines, so it is impossible to perform the image recording using a large recording medium whose size is in excess of the movable range of the movable guides. 
     In this connection, JP 2003-261249 A (hereinafter referred to as Patent Document 2) discloses an image recording apparatus having a regulating guide composed of a central guide situated at the center in the width direction and having at either end in the width direction a groove for regulating a position of one end of each recording medium, two movable guides which have on inner sides with respect to the width direction grooves for regulating positions of the other ends of the recording media and which are situated on both sides in the width direction of the central guide and movable in the width direction, and a retreat mechanism which moves the central guide in a direction (hereinafter referred to as the vertical direction) substantially perpendicular to a recording medium transport plane to thereby cause the central guide to retreat from the transport plane where transport is effected along the movable guides. 
     As in the case of Patent Document 1, with this regulating guide, it is possible to perform the parallel transport in conformity with recording media of various sizes by the central guide and the movable guides. Further, with this regulating guide, by vertically moving the central guide, it is also possible to perform the single-line transport using the movable guides alone. 
     SUMMARY OF THE INVENTION 
     However, the regulating guide disclosed in Patent Document 2 can only be applied to two types of transport, that is, the single-line transport and the parallel transport in a fixed number of lines, for example, two lines, resulting in a rather low degree of freedom. 
     Further, in the regulating guide disclosed in Patent Document 2, it is necessary to provide the retreat mechanism for causing the central guide to retreat completely from the transport plane for the single-line transport, with the result that the image forming apparatus is rather large and complicated. Further, due to its construction, in this regulating guide, the central guide which serves as the positional reference in the width direction for the recording media in the case of the parallel transport is moved in the vertical direction, so the positional accuracy for the central guide in the width direction is rather low due to an error, a margin inevitable in operation, etc. Therefore, there has been a problem in that the requisite positional accuracy for the recording media in the width direction is difficult to attain, which is likely to lead to an improper print output attributable to an error in image recording position, etc. 
     In addition, in the image recording apparatus as disclosed in Patent Document 1 and Patent Document 2, the central guide used in the parallel transport is fixed in the width direction, so in the case, for example, of the image recording by a so-called full width array (FWA) system in which the image recording is performed by using a line head having a nozzle line (i.e., line of nozzles ejecting ink droplets) longer than the maximum width of the recording medium to be used, unevenness in frequency of use is generated among the nozzles, and there is involved deterioration in the recording elements (i.e., nozzles) of high frequency of use, that is, deterioration in ejection performance due to local degradation of the recording elements, making it impossible to maintain a satisfactory ejection performance for the head as a whole. 
     Further, in the regulating guide as disclosed in Patent Document 1, it is possible for a user to arrange the movable guides at the positions on the support plate where the mounting portions are arranged through attachment/detachment of the movable guides. However, the movable guides cannot be arranged at other positions. Thus, the width of the transport path of the recording medium can only be set to a predetermined width, which means the degree of freedom in terms of print size is rather low. Further, when changing the width of the transport path, it is necessary for a user to manually move the movable guides, resulting in a rather poor operational efficiency. 
     Further, with the regulating guide disclosed in Patent Document 2, it is possible to perform the parallel transport in conformity with recording media of various sizes (widths) by the central guide and the pair of movable guides whose positions can be adjusted in the width direction. However, the positions of the movable guides of this regulating guide can only be adjusted symmetrically with respect to the central guide. That is, with this regulating guide, the parallel transport can only be performed on recording media of the same width, which means a rather low degree of freedom in terms of print size in the parallel transport. 
     It is a first object of the present invention to solve the above-mentioned problems in the conventional techniques and to provide an image recording apparatus which is small and of simple construction, which can be easily applied not only to the single-line transport but also to a plurality of kinds of parallel transport in two lines, three lines, etc., and which can ensure the requisite positional accuracy in the width direction for the recording media in the case of the parallel transport. 
     It is a second object of the present invention to provide an image forming apparatus which is small and of simple construction, which easily allows switching between the single-line transport and the parallel transport, and which can ensure the requisite positional accuracy in the width direction for the recording media in the case of the parallel transport. 
     Another object of the present invention is to provide an image recording apparatus in which, when using in particular a line head, the position in the width direction of the transport path for the parallel transport of the recording media (hereinafter referred to as the parallel path) is changed, whereby the frequency of use of each recording element of the head is leveled out, thereby making it possible to maintain a satisfactory image recording performance for the head as a whole. 
     It is a third object of the present invention to provide an image recording apparatus capable of easily performing the parallel transport on a plurality of recording media of different sizes (widths). 
     In order to achieve the above first object, a first aspect of the present invention is to provide an image recording apparatus, including: 
     an image recording section for recording an image on a recording medium; 
     a loading section for loading the recording medium; 
     feeding means for feeding the recording medium from the loading section to the image recording section; 
     a discharging section for discharging the recording medium on which the image has been recorded in the image recording section; 
     transport means for transporting the recording medium from the loading section to the discharging section; 
     a regulating guide which is arranged in a transport path for the recording medium transported by the transport means from the loading section to the discharging section and which regulates a position of the recording medium in a width direction perpendicular to a transport direction of the recording medium transported by the transport means, wherein the regulating guide has:
         a pair of outer guides arranged at outermost positions in the width direction and having in a direction perpendicular to a transport plane for the recording medium plural outer passage portions for regulating a position of one end portion of the recording medium in the width direction, and   at least one inner guide arranged between the pair of outer guides and having on both sides in the width direction inner passage portions for regulating a position of another end portion of the recording medium in the width direction at a position in the direction perpendicular to the transport plane for the recording medium corresponding to one outer passage portion of the pair of outer guides, and wherein the regulating guide forms plural passages in the direction perpendicular to the transport plane for the recording medium, the plural passages including:   a first passage formed by two corresponding outer passage portions of the pair of outer guides, and   at least one second passage formed by the other one outer passage portion of one of the pair of outer guides and one of the inner passage portions of the at least one inner guide corresponding to the other one outer passage portion; and       

     passage changing means for regulating the transport direction of the recording medium in the direction perpendicular to the transport plane for the recording medium and changing the first passage and one of the at least one second passage to guide the recording medium to a changed passage. 
     In accordance with the image recording apparatus of the first aspect of the present invention, preferably, the image recording apparatus further including: first movement means for moving the pair of outer guides in the width direction of the transport path for the recording medium, respectively, wherein the pair of outer guides are movable in the width direction. Further, preferably, the at least one inner guide is fixed in position. Further, preferably, each of the pair of outer guides has two outer passage portions, and the at least one inner guide is an inner guide having an inner passage portion corresponding to one of the two outer passage portions. 
     Further, preferably, the passage changing means includes: a roller pair arranged immediately upstream the regulating guide, for transporting the recording medium in a nipping state; a leading guide provided integrally with the roller pair, for regulating the recording medium to guide the recording medium into one of the plural passages for the recording medium in the direction perpendicular to the transport plane for the recording medium; and rocking means for rocking the roller pair and the leading guide. Alternately, preferably, the passage changing means includes: a leading guide which is provided on upstream end portions of the pair of outer guides and the at least one inner guide and which rocks the upstream end portions in the direction perpendicular to the transport plane for the recording medium using the pair of outer guides and/or the at least one inner guide as a fulcrum. 
     In order to achieve the above second object, a second aspect of the present invention is to provide an image recording apparatus, including: 
     an image recording section for recording an image on a recording medium; 
     a loading section for loading the recording medium; 
     feeding means for feeding the recording medium from the loading section to the image recording section; 
     a discharging section for discharging the recording medium on which the image has been recorded in the image recording section; 
     transport means for transporting the recording medium from the loading section to the discharging section; 
     a regulating guide which is arranged in a transport path for the recording medium transported by the transport means from the loading section to the discharging section and which regulates a position of the recording medium in a width direction perpendicular to a transport direction of the recording medium transported by the transport means, wherein the regulating guide has:
         a pair of outer guides arranged at outermost positions in the width direction and having in a direction perpendicular to a transport plane for the recording medium two outer passage portions for regulating a position of one end portion of the recording medium in the width direction, and   a pair of inner guides arranged between the pair of outer guides and having in the width direction an inner passage portion for regulating a position of another end portion of the recording medium in the width direction at a position in the direction perpendicular to the transport plane for the recording medium corresponding to one outer passage portion of the pair of outer guides, and wherein the regulating guide forms plural passages in the direction perpendicular to the transport plane for the recording medium, the plural passages including:   a first passage that is formed by two corresponding outer passage portions of the pair of outer guides, and   a second passage that is formed by the other one outer passage portion of one of the pair of outer guides and the inner passage portion of one of the pair of inner guides corresponding to the other one outer passage portion;       

     first movement means for moving the pair of outer guides to arrange the pair of outer guides at symmetrical positions with respect to a central position of the first passage for the recording medium in the width direction; 
     second movement means for moving the pair of inner guides to arrange the pair of inner guides at symmetrical positions with respect to the central position; and 
     passage changing means for regulating the transport direction of the recording medium in the direction perpendicular to the transport plane for the recording medium and changing the first passage and the second passage to guide the recording medium to a changed passage. 
     Here, preferably, the pair of inner guides have second inner passage portions on sides opposed to each other in the width direction. 
     Further, preferably, the recording section includes a line head with recording elements arranged over a length including a maximum recording width in the width direction and performs image recording on the recording medium by the line head, and the image recording apparatus further includes: storage means for storing a number of times that each recording element of the line head is driven; and control means for driving the first movement means and the second movement means according to the number of times of driving stored in the storage means to determine the position of the regulating member. 
     Further, in order to achieve the above third object, a third aspect of the present invention is to provide an image recording apparatus, including: 
     an image recording section for recording an image on a recording medium; 
     a loading section for loading the recording medium; 
     feeding means for feeding the recording medium from the loading section to the image recording section; 
     a discharging section for discharging the recording medium on which the image has been recorded in the image recording section; 
     transport means for transporting the recording medium from the loading section to the discharging section; 
     a regulating guide which is arranged in a transport path for the recording medium transported by the transport means from the loading section to the discharging section and which regulates a position of the recording medium in a width direction perpendicular to a transport direction of the recording medium transported by the transport means, wherein the regulating guide has:
         a pair of outer guides arranged at outermost positions in the width direction for regulating a position of one end portion of the recording medium in the width direction, and   at least one inner guide arranged between the pair of outer guides and having on both sides in the width direction guide portions for regulating a position of another end portion of the recording medium in the width direction; and       

     movement means for moving at least two of the pair of outer guides and the at least one inner guide continuously in the width direction independently of each other. 
     In accordance with the image recording apparatus of the third aspect of the present invention, preferably, the pair of outer guides have in the direction perpendicular to the transport plane for the recording medium plural outer passage portions for regulating the position of the one end portion of the recording medium in the width direction, and at least one inner guide has as the guide portions on both sides in the width direction inner passage portions for regulating the position of another end portion of the recording medium in the width direction at a position in the direction perpendicular to the transport plane for the recording medium corresponding to one outer passage portion of the pair of outer guides, wherein the regulating guide forms plural passages in the direction perpendicular to the transport plane for the recording medium, the plural passages including: a first passage formed by two corresponding outer passage portions of the pair of outer guides; and at least one second passage formed by the other one outer passage portion of one of the pair of outer guides and one of the inner passage portions of the at least one inner guide corresponding to the other one outer passage portion, and the image recording apparatus further includes: passage changing means for regulating the transport direction of the recording medium in the direction perpendicular to the transport plane for the recording medium and changing the first passage and one of the at least one second passage to guide the recording medium to a changed passage. 
     Here, preferably, the passage changing means includes: a roller pair arranged immediately upstream the regulating guide, for transporting the recording medium in a nipping state; a leading guide provided integrally with the roller pair, for regulating the recording medium to guide the recording medium into one of the plural passages for the recording medium in the direction perpendicular to the transport plane for the recording medium; and rocking means for rocking the roller pair and the leading guide. 
     Further, preferably, the passage changing means includes: a leading guide which is provided at upstream end portions of the pair of outer guides and the at least one inner guide and which is adapted to rock the upstream end portions in the direction perpendicular to the transport plane for the recording medium using the pair of outer guides and/or the at least one inner guide as a fulcrum. 
     Further, preferably, the movement means moves at least the pair of outer guides independently of each other and continuously in the width direction. 
     In each of the above aspects, preferably, the passage changing means regulates a leading end of the recording medium in the direction perpendicular to the transport plane for the recording medium and guides the leading end of the recording medium into the changed passage. 
     In the image recording apparatus of the first aspect of the present invention constructed as described above, the regulating guide for regulating the position of the recording medium includes a plurality of passages (hereinafter also referred to as transport path) in a direction perpendicular to the transport plane and changes the transport path of the recording medium according to the number of transport lines of recording media including that of the singe-line transport, so it is possible for the image recording apparatus to be applied, with a simple construction, not only to two modes of transport of the single-line transport and the parallel transport in two lines but also to various other modes of transport, such as the single-line transport, the parallel transport in two lines, and the parallel transport in three lines. 
     Further, there is no need for the guide member used at the time of the parallel transport to be moved in the direction perpendicular to the transport plane, so it is possible to achieve high positional accuracy for the guide member, that is, it is possible to ensure in a stable manner high positional accuracy in the width direction for the recording medium, making it possible to perform proper image recording. 
     In the image recording apparatus according to the second aspect of the present invention constructed as described above, the regulating guide for regulating the position in the width direction of the recording medium includes two passages (i.e., transport paths) in a direction perpendicular to the transport plane, and the transport path of the recording medium is changed according to the number of recording medium transport lines including that of the singe-line transport, so it is possible to realize, with a simple construction, the single-line transport and the parallel transport in two or three lines. 
     Further, there is no need to move the guide member used at the time of the parallel transport in the direction perpendicular to the transport plane, so the positional accuracy for the guide member is high, that is, it is possible to ensure in a stable manner high positional accuracy in the width direction for the recording medium, making it possible to perform proper image recording. 
     Further, the pair of outer guides arranged in the width direction of the transport plane and the pair of inner guides arranged between the pair of outer guides are movable symmetrically with respect to the central position in the width direction of the transport path and independently of each other, so it is possible to regulate the recording medium to the transport path in the width direction with high degree of freedom, making it possible to perform the image recording on recording media of various sizes (widths). 
     Further, as stated above, in the image recording apparatus of another embodiment according to the second aspect of the present invention, the pair of outer guides and the pair of inner guides are movable symmetrically with respect to the central position in the width direction of the transport path and independently of each other, so it is possible to set the transport position of the recording medium with high degree of freedom in the width direction, and even when the image recording is performed by using a line head, the frequency of use of each recording element is leveled out to prevent local deterioration of the recording elements, thereby making it possible to maintain a satisfactory recording performance for the head as a whole. 
     In the image recording apparatus according to the third aspect of the present invention constructed as described above, there is provided movement means which makes at least two of the pair of outer guides and at least one inner guide movable in the width direction independently of each other and continuously, whereby it is possible, at the time of the parallel transport, to set independently and arbitrarily the width of the passage (i.e., transport path) of the recording medium for the parallel transport in at least two lines. Further, there is no need for a user to manually change the width of the transport path, making it possible to easily change the width of the transport path. Thus, with the image recording apparatus of the present invention, it is possible to easily perform the parallel transport on recording sheets of various different widths. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the accompanying drawings: 
         FIG. 1  is a schematic conceptual drawing showing an embodiment of an ink jet printer using an image recording apparatus according to the present invention; 
         FIGS. 2A ,  2 B, and  2 C are respectively a schematic plan view, a schematic front view, and a schematic side view of one embodiment of a regulating guide unit according to the first aspect of the present invention used in the ink jet printer shown in  FIG. 1 ; 
         FIGS. 3A and 3B  are respectively a schematic front view and a schematic side view for illustrating the operation of the regulating guide unit shown in  FIGS. 2A through 2C ; 
         FIGS. 4A and 4B  are respectively a schematic front view and a schematic side view for illustrating the operation of the regulating guide unit shown in  FIGS. 2A through 2C ; 
         FIGS. 5A and 5B  are each a schematic view for illustrating the operation of the regulating guide unit shown in  FIGS. 2A through 2C ; 
         FIG. 6A  is a schematic plan view showing another embodiment of the regulating guide unit used in the image recording apparatus according to the first aspect of the present invention; 
         FIGS. 6B and 6C  are each a front view showing a different usage pattern of the regulating guide unit shown in  FIG. 6A ; 
         FIG. 7  is a schematic conceptual drawing showing still another embodiment of the regulating guide unit used in the image recording apparatus according to the first aspect of the present invention; 
         FIGS. 8A ,  8 B, and  8 C are respectively a schematic plan view, a schematic front view, and a schematic side view of still another embodiment of the regulating guide unit according to the second aspect of the present invention used in the ink jet printer shown in  FIG. 1 ; 
         FIGS. 9A and 9B  are respectively a schematic front view and a schematic side view for illustrating the operation of the regulating guide unit shown in  FIGS. 8A through 8C ; 
         FIGS. 10A and 10B  are respectively a schematic front view and a schematic side view for illustrating the operation of the regulating guide unit shown in  FIGS. 8A through 8C ; 
         FIGS. 11A and 11B  are each a schematic view for illustrating the operation of the regulating guide unit shown in  FIGS. 8A through 8C ; 
         FIG. 12A  is a schematic plan view showing still another embodiment of the regulating guide unit used in the image recording apparatus according to the second aspect of the present invention; 
         FIGS. 12B and 12C  are each a front view showing a different usage pattern of the regulating guide unit shown in  FIG. 12A ; 
         FIG. 13  is a schematic conceptual drawing showing still another embodiment of the regulating guide unit used in the image recording apparatus according to the second aspect of the present invention; 
         FIGS. 14A and 14B  are each a schematic conceptual drawing illustrating the operation of the image recording apparatus according to the second aspect of the present invention which comprises a line head as recording means; 
         FIGS. 15A ,  15 B, and  15 C are respectively a schematic plan view, a schematic front view, and a schematic side view of still another embodiment of the regulating guide unit according to the third aspect of the present invention used in the ink jet printer shown in  FIG. 1 ; 
         FIGS. 16A and 16B  are respectively a schematic front view and a schematic side view for illustrating the operation of the regulating guide unit shown in  FIGS. 15A through 15C ; 
         FIGS. 17A and 17B  are respectively a schematic front view and a schematic side view for illustrating the operation of the regulating guide unit shown in  FIGS. 15A through 15C ; 
         FIGS. 18A and 18B  are respectively a schematic front view and a schematic side view for illustrating the operation of the regulating guide unit shown in  FIGS. 15A through 15C ; 
         FIGS. 19A and 19B  are each a schematic view for illustrating the operation of the regulating guide unit shown in  FIGS. 15A through 15C ; 
         FIG. 20A  is a schematic plan view showing still another embodiment of the regulating guide unit used in the image recording apparatus according to the third aspect of the present invention; and 
         FIGS. 20B and 20C  are each a front view showing a different usage pattern of the regulating guide unit shown in  FIG. 20A . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the following, preferred embodiments of the image recording apparatus of the present invention will be described in detail with reference to the accompanying drawings. 
     The image recording apparatus of the first aspect of the present invention will be explained referring to  FIGS. 1 to 7 . First, an ink jet printer which applies the image recording apparatus of each of the first to third aspects of the present invention will be explained. 
       FIG. 1  is a conceptual drawing showing one embodiment of the ink jet printer using the image recording apparatus according to the present invention. 
     An ink jet printer shown in  FIG. 1  (hereinafter referred to as a printer)  10  performs, on a recording sheet S, not only image recording by ink jet but also, as needed, a surface treatment for realizing back printing and a quality equivalent to that of a photograph before outputting a print. The printer  10  basically comprises a recording sheet supplying section  12 , a back printer  14 , an image recording section  16 , a surface treatment section  18 , a cutting section  20 , and a discharging section  22 . Further, the printer  10  comprises a control section  24  for control and management of operation of the printer  10  as a whole, management of historical operational data, etc. 
     Apart from the components shown, as needed, the printer  10  may naturally include various components of a well-known printer, such as a transport roller pair, a guide roller, a guide member, and a sensor for detecting the recording sheet S or the like. 
     The recording sheet supplying section  12  is a section for supplying the recording sheet S, which serves as the recording medium, to the back printer  14 , and includes a first loading section  30 , a second loading section  32 , a recording sheet loading section  34 , guide rollers  36  and  38 , a guillotine cutter  40 , a sheet feeding roller  44 , and two transport roller pairs  50  ( 50   a  and  50   b ). 
     The first loading section  30  and the second loading section  32  are both loaded with a rolled recording sheet Sr formed by winding a long recording sheet S around a core, and feed the recording sheet to the back printer  14  (and downstream sections thereof) through the cutter  40  described below. When the recording sheet S has an ink receiving layer, the recording sheet S is wound with the ink receiving layer facing outwards. 
     The first loading section  30  and the second loading section  32  are of the same construction except that they differ in their positions in the printer  10 , so the same component will be indicated by the same reference numerals, and the following description will center on the first loading section  30 . 
     The first loading section  30  (or the second loading section  32 ) comprises two flange rotating rollers  46  and a feed roller pair  52  whose rotating direction is matched with the recording sheet feeding direction (i.e., their axes extend in a direction perpendicular to the paper surface of  FIG. 1 ). The flange rotating rollers  46  are arranged in the transport direction while being spaced apart from each other by a predetermined interval. 
     The feed roller pair  52  is a well-known transport roller pair. The flange rotating rollers  46  and the feed roller pair  52  are both engaged with a well-known rotation drive source (not shown) and are rotated in a normal direction (i.e., the sheet feeding direction) or in a reverse direction (i.e., the sheet rewinding direction). 
     In the printer  10  shown, the rolled recording sheet Sr is held between two disc-like flanges F (that is, held in the axial direction) having at the center a cylindrical portion Fc fitted onto a core, and, in this state, is placed on the two flange rotating rollers  46 , whereby it is loaded at a predetermined position in the printer  10  (i.e., in the first loading section  30  or the second loading section  32 ). The outer diameter of the flange F is larger than the maximum diameter of the applicable rolled recording sheet Sr. 
     When preparing prints through parallel transport in two lines described below, two rolled recording sheets Sr each held between the flanges F are placed on the flange rotating rollers  46  to be arranged side by side in the axial direction (i.e., in a direction perpendicular to the paper surface of  FIG. 1 ). 
     In the first loading section  30  (or the second loading section  32 ), the flanges F are rotated by the flange rotating rollers  46 , and the recording sheet S is transported by the feed roller pair  52  in synchronism therewith, whereby the rolled recording sheet Sr is fed as the recording sheet S. In this process, the flanges F also function as feeding guide members for the recording sheet S. 
     In the present invention, the method of loading the rolled recording sheet Sr is not restricted to the above-described one. It is possible to utilize all the roll sheet loading methods as adopted in various printers, such as the method using a magazine accommodating the rolled recording sheet Sr rotatably supported at the center, with the magazine being loaded at a predetermined loading position. 
     The rolled recording sheet Sr as the recording sheet S loaded in the first loading section  30  is guided by the guide roller  36 , and transported (i.e., sent out) to the back printer  14  and then to the recording section  16  through the cutter  40 . Similarly, the rolled recording sheet Sr as the recording sheet S loaded in the second loading section  32  is guided by the guide roller  38 , and transported (i.e., sent out) to the back printer  14  and then to the recording section  16  through the cutter  40 . 
     The cutter  40  is a well-known guillotine cutter. The cutter  40  does not cut the recording sheet S for each print. Instead, the cutter  40  cuts the recording sheet S with a preset (or preselected) predetermined timing, for example, for each document, or when print preparation is to be interrupted (or terminated), or when the operation of the printer  10  is to be stopped. 
     That is, in the printer  10  shown, when a print is to be prepared by using the rolled recording sheet Sr as the long recording sheet S, back printing by the back printer  14 , image recording by the image recording section  16 , and surface treatment by the surface treatment section  18  (as needed), are performed on the long recording sheet S, and then cutting is performed at the cutting section  20  to obtain separate prints P. 
     Thus, when preparing prints by using the rolled recording sheet Sr as the recording sheet S, as in the case of a well-known printer using a recording medium wound up into a roll (so-called roll sheet), the rolled recording sheet Sr is sent out from the first loading section  30  or the second loading section  32  to be used as the recording sheet S, and its leading end is brought to a predetermined position (e.g., the most upstream roller pair of the image recording section  16 ) by a predetermined route, i.e., through the guide roller  36  or  38 , the cutter  40 , etc. 
     After the recording sheet S is cut by the cutter  40 , when, in the print preparation, the recording sheet S cut is not to be used, the flange rotating rollers  46  and the feed roller pair  52  are caused to make reverse rotation to rewind the recording sheet S to a predetermined position. In this process, the flanges F also function as a guide for properly guiding the recording sheet S. 
     The recording sheet loading section  34  is a section for loading cut recording sheets S previously cut into sheets of a predetermined size. 
     The cut recording sheets S are accommodated in a well-known cassette  48  as used in various printers. When the cassette  48  is loaded at a predetermined position in the recording sheet loading section  34 , the cut recording sheets S are loaded at a predetermined position in the printer  10 . In the illustrated example, when each cut recording sheet S has an ink receiving layer, the cut recording sheets S are accommodated in the cassette  48  with the ink receiving layers facing downward. 
     The cut recording sheets S accommodated in the cassette  48  are extracted from the cassette  48  by the sheet feeding roller  44 , which is a semicircular roller (i.e., a D-shaped roller) whose side peripheral surface is cut into a flat surface, and are further transported by the transport roller pairs  50   a  and  50   b  before being supplied to the back printer  14  by a transport guide, etc. (not shown). 
     In the printer  10  in the illustrated example, there are no particular limitations regarding the recording sheet S. It is possible to use various types of well-known recording sheet S (image receiving paper (image receiving medium)), such as an ordinary paper (plain paper), and an ink jet recording paper for photographic quality printing, such as an ink jet recording paper having on a surface thereof a matte or glossy ink receiving layer, an ink jet recording paper having an ink receiving layer formed of thermoplastic resin particles and a pigment ink solvent adsorption layer under the ink receiving layer (see JP 2005-35050 A, etc.), and an ink jet recording paper having an ink receptive thermoplastic resin layer as the ink receiving layer. 
     Examples of the thermoplastic resin for use in the ink jet recording paper for photographic quality printing include polyacryl ester, polycarbonate, polyacrylonitrile, polystyrene, polybutadiene, poly(meth)acrylic acid, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyester, polyamide, polyether, and a copolymer of those substances. Above all, preferred examples of the copolymer include polyacrylic ester copolymer, styrene/acrylicester copolymer, vinylchloride/vinylacetate copolymer, vinylchloride/acrylicester copolymer, ethylene/vinylacetate copolymer, ethylene/acrylicester copolymer, and SBR latex. 
     As stated below, the image recording apparatus of the present invention is not restricted to an ink jet printer. According to the image recording method, it is possible to use various types of recording media, such as silver halide photography photosensitive material, thermal recording material, thermal heat development recording material, and an electrophotographic recording paper for photographic quality printing having a thermoplastic resin layer as an image receiving layer. 
     Further, the printer  10  (i.e., the image recording apparatus) of the present invention is not restricted to the combined use of a roll sheet and cut sheets. It is also possible for the printer to use a roll sheet alone or cut sheets alone. 
     When using a roll sheet, instead of cutting it into individual prints at the last stage, it is also possible to cut the recording sheet S immediately after drawing it out of the loading section and to perform back printing or image recording on the cut sheet thus obtained. 
     The back printer  14  performs back printing on the back surface of the recording sheet S (i.e., the non-image-recording surface (back surface of the ink receiving layer in the case of a recording sheet S having an ink receiving layer) by a dot impact printer or the like. Alternatively, it is possible to perform back printing by an ink jet printer or a thermal printer. 
     There are no particular limitations regarding the content to be printed through back printing. Examples to be printed through back printing include various information which is standardized in photographic printing. 
     The image recording section  16  is a section for recording an image by ink jet on the long recording sheet S or the cut recording sheet S. The image recording section  16  comprises, from the upstream side to the downstream side with respect to the transport direction of the recording sheet S, a regulating guide  54  ( 154 ,  254 ) constituting a regulating guide unit  55  ( 155 ,  255 ) which is the feature of the present invention, a recording unit  56  for recording an image on the recording sheet S, and drying means  58 . As described below, the regulating guide  154  and  254  of the regulating guide units  155  and  255  are respectively used in the second and the third aspect of the present invention instead of the regulating guide  54  of the regulating guide unit  55  used in the first aspect of the present invention, so the regulating guide  54  and the regulating guide unit  55  are explained as a typical example for the explanation of the whole configuration of the ink jet printer  10  shown in  FIG. 1 . 
     Further, a transport roller pair  50   c  is arranged on the upstream side of the regulating guide  54 , a transport roller pair  50   d  is arranged between the regulating guide  54  and the recording unit  56 , and a transport roller pair  50   e  is arranged between the recording unit  56  and the drying means  58 . 
     The transport roller pair  50   c  comprises its inclination mechanism ( 81 : refer to  FIGS. 2A to 2C ) and constitutes the passage changing means of the present invention. The transport roller pair  50   c  comprising the inclination mechanism ( 81 ) that functions as the passage changing means, the regulating guide  54 , and the transport roller pair  50   d  constitute the regulating guide unit  55 . 
     In the example shown, the printer  10  is an apparatus capable of performing image recording (that is, print preparation) through the single line transport, in which only one recording sheet S is transported, and performing image recording through the parallel transport in two lines, in which two recording sheet S are transported while being arranged in a direction (hereinafter referred to as the width direction) perpendicular to the transport direction (i.e., the longitudinal direction in the case of the long recording sheet S). By making such the parallel transport possible, it is possible to enhance the productivity of the printer  10 . 
     The regulating guide  54  arranged on the upstream side of the recording unit  56  (i.e., between the transport roller pairs  50   c  and  50   d ) regulates the recording sheet S which is transported to the recording unit  56  for performing image recording by ink jet to a predetermined position in a direction (hereinafter referred to as a width direction) perpendicular to the transport direction of the recording sheet S. 
     The image recording apparatus according to the first aspect of the present invention will be explained in detail below by explaining various regulating guide units  55  and  55   a  shown in  FIGS. 2A to 7  that are applied to the ink jet printer  10  shown in  FIG. 1 . 
       FIGS. 2A through 2C  show schematic views of the regulating guide unit  55  comprising the transport roller pair  50   c  including the inclination mechanism  81  which functions as the passage changing means, the regulating guide  54 , and the transport roller pair  50   d  used in the ink jet printer  10  shown in  FIG. 1 , in which  FIG. 2A  is a plan view thereof (i.e., a top view of  FIG. 1 ),  FIG. 2B  is a front view (seen in the same direction as in  FIG. 1 ), and  FIG. 2C  is a side view (as seen from the upstream side with respect to the transport direction for the recording sheet S, and the right-hand side in the figure is the upper side) showing only the regulating guide. To clarify the construction, the transport roller pairs  50   c  and  50   d  are omitted in  FIG. 2C . Further, to clarify the construction, frames  64   a  and  64   b  described below are omitted in  FIG. 2B . 
     The transport roller pair  50   c  and the transport roller pair  50   d  are each a transport roller pair composed of a driving roller  60  (with the rotation drive source omitted) on the lower side and a driven roller  62  on the upper side. All the rollers are divided rollers (i.e., comb-teeth rollers) divided in the width direction. 
     The driving roller  60  of the transport roller pair  50   c , and the driving roller  60  and the driven roller  62  of the transport roller pair  50   d  are rotatably supported by the frames  64   a  and  64   b , and the driven roller  62  of the transport roller pair  50   c  is rotatably supported by brackets  82  of the inclination mechanism  81  described below. This feature will be described in detail below. 
     Basically, the regulating guide  54  comprises a central fixed guide  68  which is fixed in position at the center in the width direction, two variable-width guides  70  and  72  arranged on both sides in the width direction of the central fixed guide  68 , a screw shaft  74 , and a guide shaft  76 . In the example shown, the central fixed guide  68  corresponds to the inner guide, and the variable-width guides  70  and  72  correspond to the outer guides. 
     The screw shaft  74  extends in the width direction, is rotatably supported by the frames  64   a  and  64   b , and is turned by a rotation drive source (not shown). The screw shaft  74  is a so-called double-end screw shaft having a right-hand thread on one outer side of the center in the axial direction and a left-hand thread on the other outer side of the center in the axial direction. 
     On the other hand, the guide shaft  76  is a bar-like member extending in the width direction and fixed to the frames  64   a  and  64   b.    
     The central fixed guide  68  is a guide member which, when image recording is performed on the recording sheets S transported in parallel in two lines, regulates the position of the end on the central side of each recording sheet S with respect to the width direction (hereinafter, this side will be simply referred to as inner side, and the sides opposite thereto will be referred to as the outer sides). 
     In the example shown, the central fixed guide  68  exhibits a substantially H-shaped sectional configuration, and has slit-like passage portions (i.e., the inner passage portions)  68   a  and  68   b  through which the inner side end portions of two recording sheets S transported in parallel pass, with each of the inner passage portions being open at one end and closed at the other end. 
     The central fixed guide  68  is fixed at a predetermined position at the center in the width direction of a transport path for the recording sheet S, with the H-shaped section being visible in the transport direction and the open ends of the passage portions  68   a  and  68   b  being directed outwards. 
     On the other hand, both the variable-width guides  70  and  72  are guide members which, in the case of the single-line transport, regulate the positions of the end portions in the width direction of one recording sheet S, and which, in the case of the parallel transport, regulate the positions of the respective outer end portions of two recording sheet S. 
     The variable-width guide  70  comprises a guide portion  78  with a substantially E-shaped sectional configuration having slit-like passage portions (i.e., an outer passage portions)  70   a  and  70   c  through which the end portion of the recording sheet S (one end portion in the case of the single-line transport, and the outer end portions in the case of the parallel transport) passes and which are open at one end and closed at the other end, with a rib  70   r  being provided therebetween, and an engagement portion  80  provided on the guide portion  78  (on the E-shaped portion). The variable-width guide  72  has a construction similar to that of the variable-width guide  70 ; it has a guide portion  78  with a substantially E-shaped sectional configuration having passage portions  72   b  and  72   c  through which the end portion of the recording sheet S passes and the engagement portion  80  provided on the guide portion  78 . 
     The variable-width guides  70  and  72  are respectively arranged on either side in the width direction of the central fixed guide  68  (i.e., on the outer sides in the width direction of the central fixed guide  68 ), with the E-shaped portions being visible in the transport direction, the open ends of the passage portions being directed inwardly, and the two passage portions being stacked together in a direction (hereinafter referred to as a vertical direction) perpendicular to the transport plane for the recording sheet S. 
     As the preferred aspect, the central fixed guide  68  and the variable-width guides  70  and  72  shown in  FIG. 2B  are configured such that the upstream end portions of their passage portions expand gradually toward the upstream side, thereby enabling the recording sheet S to be inserted into the passage portions easily and reliably. 
     The engagement portion  80  of each of the variable-width guides  70  and  72  has a screw hole  80   a  into which the screw shaft  74  is screwed, and a guide hole  80   b  through which a part of the guide shaft  76  is passed while slightly in slide contact therewith. 
     One of the right-hand thread and the left-hand thread of the screw shaft  74  is screwed into the screw hole  80   a  of the variable-width guide  70 , and the other thread of the screw shaft  74  is screwed into the screw hole  80   a  of the variable-width guide  72 . 
     Further, the variable-width guides  70  and  72  are arranged so as to be outwardly spaced apart from the center in the width direction by the same distance, with the central fixed guide  68  being therebetween. 
     Thus, by turning the screw shaft  74 , the variable-width guides  70  and  72  move toward or away from each other symmetrically with respect to the center in the width direction (i.e., the central fixed guide  68 ) according to the turning direction, thus making it possible to adjust the distance therebetween and the distances between them and the central fixed guide  68 . 
     In the regulating guide  54  shown, the central fixed guide  68  and the variable-width guides  70  and  72  are arranged such that the passage portions  68   a  and  68   b  of the central fixed guide  68 , the passage portion  70   a  of the variable-width guide  70 , and the passage portion  72   b  of the variable-width guide  72  are at the same vertical position, 
     The central fixed guide  68  is fixed at a position lower than the plane connecting the passage portion  70   c  of the variable-width guide  70  and the passage portion  72   c  of the variable-width guide  72 . 
     That is, in the regulating guide  54 , two passages (hereinafter also referred to as transport paths) are formed in the vertical direction, and as shown in  FIGS. 3A and 3B , when performing the parallel transport in two lines, in the lower transport path where the central fixed guide  68  is arranged is used, one recording sheet S is regulated in its position in the width direction and undergoes positioning in the width direction by the passage portion  68   a  of the central fixed guide  68  and the passage portion  70   a  of the variable-width guide  70 , and the other recording sheet S is regulated in its position in the width direction and undergoes positioning in the width direction by the passage portion  68   b  of the central fixed guide  68  and the passage portion  72   b  of the variable-width guide  72  before being transported to the recording unit  56  on the downstream side. 
     As shown in  FIGS. 4A and 4B , when performing the single-line transport, the upper transport path with no central fixed guide  68  is used; a single recording sheet S is regulated in its position in the width direction and undergoes positioning in the width direction by the passage portion  70   c  of the variable-width guide  70  and the passage portion  72   c  of the variable-width guide  72  before being transported to the recording unit  56  on the downstream side. 
     By adjusting the distance between the variable-width guides  70  and  72 , it is possible to handle the recording sheets S of various sizes (i.e., widths) regardless of whether it is the single-line transport or the parallel transport that is to be performed. 
     In the printer  10  shown, the inclination mechanism  81  of the transport roller pair  50   c  arranged on the upstream side of the regulating guide  54  functions as passage changing means which regulates the vertically arranged transport paths (i.e., passages) for the recording sheet S, guiding two recording sheet S to the lower transport path for the parallel transport (hereinafter referred to as the parallel path for the sake of convenience), where the central fixed guide  68  is used and where the two recording sheets S are regulated in their positions in the width direction by the passage portion  68   a  of the central fixed guide  68  and the passage portion  70   a  of the variable-width guide  70  and by the passage portion  68   b  of the central fixed guide  68  and the passage portion  72   b  of the variable-width guide  72 , or guiding a single recording sheet S to the upper transport path for the single-line transport (hereinafter referred to as the single-line path for the sake of convenience), where the central fixed guide  68  is not used and where the single recording sheet S is regulated in its position in the width direction by the passage portion  70   c  of the variable-width guide  70  and the passage portion  72   c  of the variable-width guide  72 . 
     Hereinafter, the inclination mechanism  81  of the transport roller pair  50   c  which functions as the passage changing means will be explained. 
     As stated above, the lower driving roller  60  of the transport roller pair  50   c  is rotatably supported by the frames  64   a  and the  64   b.    
     On the other hand, the upper driven roller  62  of the transport roller pair  50   c  is rotatably supported by elongated holes  82   a  of the brackets  82  which are arranged on the inner side of the frames  64   a  and  64   b . The brackets  82  are rotatably supported by the driving roller  60  (i.e., the rotation shaft  60   a ) by virtue of holes  82   b.    
     A leading guide  83  is fixed to the brackets  82 . 
     The leading guide  83  comprises two rectangular guide plates having comb-teeth-like protrusions and recesses in their longer sides. The two guide plates forming the leading guide  83  are inserted into the roller dividing portions of the transport roller pair  50   c  with their longitudinal direction matched with the width direction and with its comb-teeth portions on the downstream side, and their end portions in the width direction are fixed between the brackets  82  so as to hold vertically, with some clearance provided, the transport paths for the recording sheet S transported by the transport roller pair  50   c . The two guide plates are fixed to the brackets  82  so that plate surfaces of those are in parallel with the transport plane of the recording sheet S transported by the transport roller pair  50   c.    
     A pin  82   c  is fixed to the upper portion of one of the brackets  82  so as to protrude inwardly. A lever  84  is engaged with the pin  82   c.    
     The lever  84  is a substantially rectangular plate member whose longitudinal direction is matched with the vertical direction, and is swingably supported at its center by a pin  84   c . The pin  84   c  is fixed, for example, to the frame  64   a . At the longitudinal ends of the lever  84 , there are formed elongated-hole-like notches  84   a  and  84   b . The pin  82   c  of the bracket  82  is inserted into and engaged with the lower notch  84   b.    
     A solenoid  86  is engaged with the upper notch  84   a  of the lever  84 . 
     The solenoid  86  is a well-known solenoid which extrudes a bar-like piston  86   a  from a predetermined position and accommodates the extruded piston in the predetermined position. The solenoid  86  is arranged so as to extrude the piston  86   a  downstream with respect to the direction in which the recording sheet S is transported. A pin  86   b  is fixed to a distal end of the piston  86   a . The pin  86   b  is inserted into and engaged with the upper notch  84   a  of the lever  84 . 
     As shown in  FIG. 2B  and  FIG. 5A , in the example shown, in the normal state (i.e., the state in which the solenoid  86  has not extruded the piston  86   a  yet), the central fixed guide  68  and the variable-width guides  70  and  72  are arranged such that the parallel path (i.e., the lower transport path where the central fixed guide  68  is used) constitutes the transport path where the recording sheet S is transported by the transport roller pairs  50   c  and  50   d.    
     Thus, as shown in  FIG. 5A , the leading guide  83  comprising the guide plates parallel to the transport path where transport is effected by the transport roller pair  50   c  is in the state in which the leading guide  83  guides the recording sheets S into the parallel path. The recording sheets S transported by the transport roller pair  50   c  are guided by the leading guide  83  and pass through the lower parallel path of the regulating guide  54  (formed by the central fixed guide  68  and the variable-width guides  70  and  72 ) to be regulated in their positions in the width direction, and are further supplied to the transport roller pair  50   d  before being transported to the recording unit  56  (i.e., a reference guide  102  thereof) on the downstream side. 
     As shown in  FIG. 5B , when, in this normal state, the solenoid  86  extrudes the piston  86   a , the piston  86   a  pushes the upper portion of the lever  84  toward the downstream side. As described above, the lever  84  is swingably supported at the center by the pin  84   c , so the lever  84  is inclined through this pushing by the piston  86   a , with its upper portion being on the downstream side and its lower portion on the upstream side. 
     Due to this inclination of the lever  84 , the pin  82   c  on the upper portion of the bracket  82  is pushed toward the downstream side. As stated above, the bracket  82  rotatably supports the driven roller  62 , and is rotatably supported by the driving roller  60  (i.e., the rotation shaft  60   a ), so the bracket  82  is inclined about the driving roller  60  through this pushing with its upper portion being directed to the upstream side. As shown in  FIG. 5B , as a result of this inclination of the bracket  82 , the driven roller  62  rotatably supported by the elongated holes  82   a  moves toward the upstream side along the driving roller  60 . Further, the leading guide  83  fixed to the bracket  82  is also inclined, and the transport path where transport is effected by the transport roller pair  50   c  and the leading guide  83  is shifted upwards to the upper transport path, i.e., the single-line path (that is, the single-line passage), where the central fixed guide  68  is not used. 
     Thus, as shown in  FIG. 5B , the recording sheet S transported from the transport roller pair  50   c  in this state is guided by the leading guide  83  and passes through the upper single-line path of the regulating guide  54  (formed by the variable-width guides  70  and  72 ) and is regulated in its position in the width direction. Further, the recording sheet S is fed and transported to the transport roller pair  50   d  before being transported to the recording unit  56  (i.e., the reference guide  102  thereof) on the downstream side. 
     In order that the recording sheet S may be reliably transported from the single-line path of the regulating guide  54  to the transport roller pair  50   d , it is possible to provide a guide member for guiding the recording sheet S from the single-line path to the transport roller pair  50   d.    
     In the present invention, the passage changing means for changing to the single-line path and the parallel path is not restricted to the above-described one. It is possible to use various types of other transport passage changing means. 
       FIGS. 6A through 6C  show one embodiment of the regulating guide unit  55   a  comprising another passage changing means, in which  FIG. 6A  is a plan view of the regulating guide unit  55   a , and  FIGS. 6B and 6C  are front views thereof. 
     The regulating guide unit  55   a  shown in  FIGS. 6A to 6C  has the same configuration as the regulating guide unit  55  shown in  FIGS. 2A to 2C  except that the regulating guide unit  55   a  comprises passage changing means  87  instead of the inclination mechanism (passage changing means)  81 . Thus, each component of the regulating guide unit  55   a  that is the same as that of the regulating guide unit  55  is given the same reference numeral, and a detailed explanation thereof is omitted. Therefore, different points will be mainly explained. 
     The passage changing means  87  of the regulating guide unit  55   a  shown in  FIGS. 6A to 6C  will be explained below. In the passage changing means  87  of the illustrated example, three plate-like leading guides  88  (flappers) for regulating the transport direction of the recording sheet S in the vertical direction are provided at the respective upstream ends of the central fixed guide  68  and the variable-width guides  70  and  72  of the regulating guide  54 . In this example, the transport roller pairs  50   c  and  50   d  are all rotatably supported by the frames  64   a  and  64   b.    
     The leading guides  88  are of a wedge-like configuration whose thickness gradually decreases in one direction. Their proximal ends (the thicker ends) are fixed to the central fixed guide  68  and the variable-width guides  70  and  72  by such means as hinges, with their thinner ends (hereinafter referred to as distal ends) being on the upstream side. Thus, they can be rocked using their proximal ends as a fulcrum. 
     Three leading guides  88  are respectively fixed to the upper portions of the upstream end portion of the central fixed guide  68  and the upstream end portions of the ribs  70   r  and  72   r  of the variable-width guides  70  and  72 . That is, the leading guides  88  are fixed in position over the lower parallel path. 
     Plate-like arms  90  are fixed to the lower surfaces of the portions in the vicinity of the distal ends of the leading guides  88 . A pin  90   a  is fixed to the lower ends of the arms  90 . 
     As shown in  FIG. 6A , the pin  90   a  fixed to the arms  90  extends in the width direction. Specifically, the single pin  90   a  passes through and is engaged with all the arms  90 , that is, the arm  90  fixed to the leading guide  88  of the central fixed guide  68 , the arm  90  fixed to the leading guide  88  of the variable-width guide  70 , and the arm  90  fixed to the leading guide  88  of the variable-width guide  72 , thereby fixing all the arms  90 . 
     A lever  92  is a substantially rectangular plate member whose longitudinal direction is matched with the transport direction and which is swingably supported at the center by a pin  92   c . The lever  92  has at its longitudinal ends elongated-hole-like notches  92   a  and  92   b . The pin  90   a  fixing the arms  90  is passed through and engaged with the upstream notch  92   a . The pin  92   c  is fixed, for example, to the frame  64   a.    
     A solenoid  86  similar to the one described above is engaged with the downstream notch  92   b  of the lever  92 . More specifically, a pin  86   b  at the distal end of the piston  86   a  of the solenoid  86  is inserted into and engaged with the downstream notch  92   b  of the lever  92 . 
     Instead of being provided for each of the central fixed guide  68  and the variable-width guides  70  and  72 , the solenoid  86  and the lever  92  are only provided one each. 
     Also in the example shown in  FIGS. 6A through 6C , the central fixed guide  68  and the variable-width guides  70  and  72  are arranged such that the transport path in which the recording sheet S is transported by the transport roller pairs  50   c  and  50   d  is matched with the parallel path (i.e., the lower transport path where the central fixed guide  68  is used). 
     As shown in  FIG. 6B , in the normal state (i.e., the state in which the piston  86   a  is not extruded), the leading guides  88  fixed in position over the lower parallel path as described above are parallel to the transport path where transport is effected by the transport roller pairs  50   c  and  50   d . Thus, the recording sheets S transported from the transport roller pair  50   c  advance as they are to pass through the lower parallel path of the regulating guide  54  (formed by the central fixed guide  68  and the variable-width guides  70  and  72 ) to be regulated in their positions in the width direction, and are further fed to the transport roller pair  50   d  before being transported to the recording unit  56  on the downstream side. 
     As shown in  FIG. 6C , when, in this normal state, the solenoid  86  extrudes the piston  86   a , the piston  86   a  upwardly pushes the downstream side of the lever  92 . As stated above, the lever  92  is swingably supported at the center by the pin  92   c , so the lever  92  is inclined through the pushing by the piston  86   a , with the downstream side thereof being higher and the upstream side thereof lower. 
     As a result of this inclination of the lever  92 , the arms  90  engaged with the pin  90   a  which is engaged with the notch  92   a  formed at the upstream end of the lever  92  move downwards, and the leading guides  88 , with the arms  90  fixed to the lower surfaces of the portions near the distal ends thereof, are inclined with their distal ends lower, thus making the transport path shifted to the upper single-line path. 
     As stated above, the pin  90   a  fixing the arms  90  is engaged with all the arms  90  respectively fixed to the leading guides  88  of all of the central fixed guide  68  and the variable-width guides  70  and  72 . Thus, by driving the solenoid  86 , the leading guides  88  of all of the central fixed guide  68  and the variable-width guides  70  and  72  are inclined downwards. 
     Thus, as shown in  FIG. 6C , in this state, the recording sheet S transported from the transport roller pair  50   c  is guided by the leading guides  88  and passes through the upper single-line transport path of the regulating guide  54  (formed by the variable-width guides  70  and  72 ) to be regulated in its position in the width direction and is further fed and transported to the transport roller pair  50   d  before being transported to the recording unit  56  (i.e., the reference guide  102  thereof) on the downstream side. 
     In the example shown, the central fixed guide  68  and the variable-width guides  70  and  72  are arranged such that the transport path where transport is effected by the transport roller pairs  50   c  and  50   d  is matched with the parallel path corresponding to the parallel transport, however, this should not be construed restrictively. 
     Taking into account the burden on the recording sheet S, it is desirable for the transport path normally used in the regulating guide  54  to be matched with the transport path where transport is effected by the transport roller pairs  50   c  and  50   d.    
     Further, in the example shown, although two transport paths are arranged in the vertical direction, this should not be construed restrictively. 
     For example, it is also possible to adopt a construction as the regulating guide  54   a  shown in  FIG. 7 , in which three passage portions are vertically arranged in variable-width guides  94  (that is, outer guides) provided outwardly in the width direction and in which second variable-width guides  96  each having on both sides thereof passage portions for the recording sheet S are provided at positions which are between the central fixed guide  68  and the variable-width guides  94  in the width direction and which do not interfere with the transport plane where the central fixed guide  68  is used, whereby it is possible to perform three modes of transport. The three modes of transport include the single-line transport indicated by the dashed line, the parallel transport in two lines indicated by the alternate long and short dashed line, and the parallel transport in three lines indicated by the chain double-dashed line. The regulating guide  54   a  shown in  FIG. 7  may be used instead of the regulating guide  54  of the above described regulating guide unit  55  and  55   a.    
     As is apparent from the above description, according to the present invention, in a regulating guide for regulating the positions in the width direction of the recording sheet S, there are formed a plurality of transport paths in the vertical direction (i.e., the direction perpendicular to the transport plane for the recording sheet S), and the single-line transport, the multiple-line transport in two lines, etc. are performed by using these transport paths, so the regulating guide can be easily adapted to a variety of transport modes, thereby making it possible to achieve a substantial improvement in degree of freedom in terms of recording modes for an image recording apparatus utilizing the parallel transport. 
     Further, since the guide does not move vertically, it is possible to minimize an error in guide position attributable to such vertical movement, that is, it is possible to perform positioning on the recording sheet S with high accuracy and to effect proper image recording free from an error in recording position, etc. In particular, when, as in the case of the example shown, the single-line transport and the multiple-line transport in two lines are performed, it is possible for the inner fixed guide  68  serving as a positioning reference for the recording sheet S in image recording, etc. to be completely in a fixed state, so it is possible to effect positioning on the recording sheet S in the width direction with very high accuracy. 
     As described above, the recording unit  56  is arranged on the downstream side of the regulating guide  54  (or the transport roller pair  50   d ). On the downstream side of the recording unit  56 , there is arranged the transport roller pair  50   e.    
     The recording unit  56  comprises well-known ink jet recording means  100  using an ink jet recording head (hereinafter referred to as recording head) and the reference guide  102  for regulating the vertical position of the recording sheet S, and performs well-known full-color image recording by ink jet on the recording sheet S on which positioning in the width direction has been effected by the regulating guide  54 . 
     There are no particular limitations regarding the method of image recording (drawing) by the recording means  100 ; it may be a well-known method using an ink jet printer. 
     Thus, as the recording means  100 , it is possible to use a line head having a nozzle line (i.e., line of nozzles for ejecting ink droplets) longer than the maximum width of the recording sheet S, and to perform the image recording while continuously transporting the recording sheet S (i.e., transport for scanning), with the nozzle line of the line head being arranged/fixed so as to be matched with the width direction, thus performing image recording by a so-called full width array (FWA) system. Alternatively, it is possible for the recording means  100  to be a small recording head with a nozzle line mounted on a carriage (that is, scanning means) so as to be matched with the transport direction for the recording sheet S, and to perform the image recording through scanning by the recording head with the transport of the recording sheet S being suspended while intermittently transporting the recording sheet S, thus performing image recording by a so-called partial width array (PWA) system. 
     Thus, when the recording means  100  is one performing image recording by the FWA system, the transport of the recording sheet S by the transport roller pairs  50   c  through  50   e  (and transport roller pair  50   f  described below) is continuous, and when the recording means  100  is one performing image recording by the PWA system, the transport of the recording sheet S by the transport roller pairs  50   c  through  50   e  (and transport roller pair  50   f  described below) is intermittent. 
     The reference guide  102  may be one simply supporting the recording sheet S from below to regulate the vertical position of the recording sheet S to a predetermined position (where the recording head is at a predetermined distance from the recording sheet S). Alternatively, it is possible to provide a suction hole in the upper surface (i.e., the transport plane for the recording sheet S, that is, the positional reference surface) of the reference guide  102 , and to prevent floating, etc. of the recording sheet S by means such as suction from inside, thereby regulating the recording sheet S to a predetermined position more reliably and accurately. 
     The means for preventing floating of the recording sheet S in the reference guide  102  is not restricted to suction; it is also possible to use various well-known methods, such as a method using static electricity. Further, the reference guide  102  may be one which not only supports the recording sheet S at a predetermined position, but also transports the recording sheet S by using well-known transport means such as a belt conveyor. Further, to prevent contamination by ink when preparing a so-called borderless print with the image recorded up to the ends thereof, the reference guide  102  may have groove-like ink receivers formed in conformity with the width of the recording sheet S concerned. 
     The drying means  58  is arranged on the downstream side of the recording unit  56  (comprising the reference guide  102  and the recording means  100 ). Between the recording unit  56  and the drying means  58 , there is arranged the transport roller pair  50   e.    
     The drying means  58  serves to dry the ink on the recording sheet S that has undergone the image recording by ink jet. There are no particular limitations regarding the drying means  58 ; it is possible to adopt various well-known methods such as a method using a heater, a method using a fan for blowing air, and a method using both a heater and a fan. 
     The transport roller pair  50   e  arranged between the reference guide  102  and the drying means  58  is separable; the rollers are separated from each other as needed to thereby prevent adhesion of undried ink. 
     In the image recording apparatus of the present invention, the image recording method is not restricted to one using ink jet; it is possible to use various well-known image recording methods, such as an image recording method in which a silver halide photography photosensitive material is used as the recording sheet and in which the silver halide photography photosensitive material is imagewisely exposed by a recording light such as a light beam to record a latent image before performing a wet developing process, an image recording method using electrophotography, an image recording method using thermal recording, and an image recording method using a photosensitive thermal development recording material as the recording sheet and in which the photosensitive thermal development recording material is imagewisely exposed by a recording beam such as a light beam to record a latent image before performing thermal development. 
     After the ink is dried by the drying means  58 , the recording sheet S is transported to the surface treatment section  18  by transport roller pairs  50   f  and  50   g . The section between the transport roller pairs  50   f  and  50   g  constitutes a loop forming section for forming a loop of the recording sheet S. This will be described in detail below. 
     When an ink jet recording sheet for photographic quality printing having an ink receiving layer formed of thermoplastic resin particles as described above, an ink receiving layer formed of an ink receptive thermoplastic resin layer or the like is used as the recording sheet S, the surface treatment section  18  performs surface treatment on the ink receiving layer (thermoplastic resin). 
     When the recording sheet S used is other than the ones mentioned above, there is basically no need to perform surface treatment in the surface treatment section  18 , so, preferably, the recording sheet S is transported downstream without performing any treatment to the recording sheet S in the surface treatment section  18 , with a nip roller  120  described below being separated from a surface treatment belt  114 . 
     However, as needed, it is naturally also possible to perform a surface treatment as described below on the recording sheet S other than an ink jet recording sheet for photographic quality printing. 
     In the surface treatment section  18 , the surface (ink receiving layer) of the recording sheet S is held in contact with the surface of the surface treatment belt  114 , and pressurization and heating are performed thereon before cooling, thereby performing surface treatment on the recording sheet S. 
     In the example shown, in addition to the surface treatment belt  114 , the surface treatment section  18  comprises a heating roller  116 , a roller  118 , the nip roller  120 , and a cooling unit  122 . The surface treatment belt  114  is an endless belt which is stretched around the heating roller  116  and the roller  118 . 
     The surface treatment belt  114  is a belt with a very high surface (outer surface) smoothness. The heating roller  116  a well-known heating roller which generates heat at a temperature corresponding to the heat treatment for the recording sheet S. The cooling unit  122  is brought into contact with the surface treatment belt  114  from the inside to cool the recording sheet S transported on the surface treatment belt  114 . Further, the nip roller  120  is brought into contact with and pressed against the surface treatment belt  114  at a position corresponding to the heating roller  116 , whereby the recording sheet S is pressed against the surface treatment belt  114  and is held and transported together with the surface treatment belt  114 . 
     There are no particular limitations regarding the heating means in the heating roller  116  and the cooling means in the cooling unit  122 ; it is possible to use any well-known means. It is also possible for the nip roller  120  to include heating means. 
     As is apparent from  FIG. 1 , the recording sheet S that has undergone the image recording by ink jet is transported to the surface treatment section  18  with the image formation surface facing the surface treatment belt  114 . 
     In the surface treatment section  18 , the recording sheet S is first held between the surface treatment belt  114  (i.e., heating roller  116 ) and the nip roller  120  and transported, whereby the surface (i.e., the ink receiving layer) of the recording sheet S is brought into contact with and pressed against the surface of the surface treatment belt  114  and, at the same time, the recording sheet S is heated by the heating roller  116 . 
     By this heating/pressurization, the ink receiving layer of the recording sheet S formed of thermoplastic resin is melted, and the recording sheet S weakly sticks to the surface treatment belt  114  while it is transported by the surface treatment belt  114 . In the surface treatment section  18 , during this transport, the recording sheet S is cooled by the cooling unit  122 , whereby the melted ink receiving layer is solidified. 
     The cooled recording sheet S is separated from the surface treatment belt  114  at the turning section using the roller  118 , and is supplied to a transport roller pair  50   h  on the downstream side. 
     The ink receiving layer (thermoplastic resin) of the recording sheet S is brought into the sticking state by thus being pressed against the surface treatment belt  114  and heated/fused. After that, the surface feature of the surface treatment belt  114  is transferred through cooling/solidification. As stated above, the surface treatment belt  114  has very high surface smoothness. Thus, the recording sheet S to which the surface property of the surface treatment belt  114  has been transferred has high surface smoothness and satisfactory glossiness, thereby making it possible to obtain a print of a quality equivalent to that of a silver halide photography print. 
     Further, in this surface treatment of the recording sheet S, the surface property of the surface treatment belt  114  is selected, whereby it is possible to perform not only the treatment to impart such glossiness, but also various other treatments, such as matting (roughening) treatment. 
     In the printer  10 , it is possible to adjust the heating condition and/or the cooling condition for the surface treatment section  18 , whereby it is also possible to adjust the glossiness, etc. to be imparted to the surface of the recording sheet S (print). 
     Further, in the example shown, the recording sheet S is separated from the surface treatment belt  114  by utilizing the so-called stiffness of the recording sheet S. Thus, preferably, as shown in  FIG. 1 , the diameter of the roller  118  which is situated at the position where the recording sheet S is discharged from the surface treatment section  18  and around which the surface treatment belt  114  is stretched is made small, whereby it is possible to achieve an improvement in terms of the ease with which the recording sheet S is separated from the surface treatment belt  114 . 
     The recording sheet S which has undergone surface treatment in the surface treatment section  18  or which has passed through the surface treatment section  18  is then transported to the cutting section  20  by transport roller pairs  50   h  and  50   i . The section between the transport roller pairs  50   h  and  50   i  constitutes a loop forming section for the recording sheet S. This will be described in detail below. 
     The cutting section  20  uses a well-known guillotine cutter  130  to cut in the width direction the long recording sheet S which is supplied from the first loading section  30  and/or the second loading section  32 , having undergone the image recording by ink jet in the image recording section  16 , and has undergone surface treatment in the surface treatment section  18  as needed, thereby obtaining a single print (prints are cut off one by one). 
     In the printer  10 , the cutting section  20  is not restricted to the cutting of a long recording sheet S (i.e., a roll sheet). For example, the cutting section  20  may also be used to cut a cut recording sheet S supplied from the recording sheet loading section  34  for cutting the leading-end/trailing-end (with respect to the transport direction) of the recording sheet S according to the print size to be output. The cutting section  20  may also be used to cut the leading-end/trailing-end of a recording sheet for preparing a so-called borderless print with an image recorded up to the ends thereof. 
     In the printer  10  of the example shown, although the cutting section  20  comprises only the cutter  130  and cuts the recording sheet S only in the width direction, this should not be construed restrictively. 
     For example, in the recording unit  56 , when a so-called multi image allocation in which two or more images are recorded in the width direction is to be performed in the width direction, the cutting section  20  may comprise cutting means such as a slitter for cutting the recording sheet S in the transport direction. 
     As stated above, the sections between the transport roller pairs  50   f  and  50   g  for transporting the recording sheet S from the image recording section  16  to the surface treatment section  18  and the section between the transport roller pairs  50   h  and  50   i  for transporting the recording sheet S from the surface treatment section  18  to the cutting section  20  each constitutes a loop forming section for forming a loop of the recording sheet S (i.e., sag in the recording sheet S). 
     In the surface treatment section  18 , the recording sheet S weakly sticks to the surface treatment belt  114  by heating/fusing the ink receiving layer of the recording sheet S, and in this state, the recording sheet S is transported/cooled for surface treatment. 
     Thus, when the transport of the recording sheet S is stopped in the surface treatment section  18 , the recording sheet S is overheated or overcooled, with the result that unevenness in surface treatment is generated, which leads to unevenness in the glossiness of the print, etc. Thus, during the treatment in the surface treatment section  18 , the transport of the recording sheet S must not be stopped. 
     Further, during the treatment of the recording sheet S in the surface treatment section  18 , if there arises a fluctuation in load in the transport of the recording sheet S, such as forcing of the recording sheet S into the surface treatment section  18  or pulling the recording sheet S out of the surface treatment section  18 , the recording sheet S sticking to the surface treatment belt  114  is allowed to be deviated, resulting in unevenness in glossiness. 
     When, however, the recording means  100  performs the image recording by the PWA system, the transport of the recording sheet S is intermittent. Also, when the recording means  100  performs the image recording by the FWA system, the transport speed (scanning transport speed) of the recording means  100  for image recording and the transport speed of the surface treatment section  18  for surface treatment may differ from each other. 
     Since the cutting section  20  uses the guillotine cutter  130 , it is necessary to stop the transport of the recording sheet S at the time of cutting. 
     In this connection, in the printer  10 , when print preparation is performed by using a long recording sheet S (i.e., a roll sheet) supplied from the first loading section  30  and/or the second loading section  32 , there is no need to stop the leading end of the recording sheet S at the transport roller pair  50   g  to stop the transport of the recording sheet S in the surface treatment section  18 ; after forming a loop of the recording sheet S between the transport roller pairs  50   f  and  50   g  by a sufficient amount not imparting a load fluctuation to the transport of the recording sheet S in the surface treatment section  18 , the transport by the transport roller pair  50   g  is started, and the recording sheet S is transported to the surface treatment section  18 . 
     Similarly, when print preparation is performed by using a long recording sheet S, there is no need to stop the leading end of the recording sheet S at the transport roller pair  50   i  to stop the transport in the surface treatment section  18 ; after forming a loop of the recording sheet S between the transport roller pairs  50   i  and  50   h  by an amount not imparting a load fluctuation, the transport by the transport roller pair  50   i  is started, and the recording sheet S is transported to the cutting section  20  (that is, the guillotine cutter  130 ). 
     Further, in order not to impart any load fluctuation to the transport of the recording sheet S in the surface treatment section  18 , the transport speed of the transport roller pairs  50   g  and  50   h  is controlled so as to coincide with the transport speed of the recording sheet S in the surface treatment section  18 . 
     Further, the transport by the transport roller pairs  50   i  and  50   j  is an intermittent transport in conformity with the driving of the guillotine cutter  130 . 
     The portions of the recording sheet S cut off by the cutting section  20  (i.e., the guillotine cutter  130 ), that is, the prints, are discharged to the discharging section  22  by transport roller pairs  50   j  and  50   k.    
     In the discharge section  22 , the prints are sorted in units of orders by using an orthogonal transport belt (i.e., the belt conveyor)  132  for effecting transport in a direction perpendicular to the paper surface of  FIG. 1 . The prints are discharged onto the orthogonal transport belt  132  of the discharging section  22  by the transport roller pair  50   k  and are stacked thereon. In a case where prints corresponding to one order have been stacked, the orthogonal transport belt  132  transports the print stack in the depth direction by an amount corresponding to a single print (i.e., its size in the width direction), and the portion of the belt where no print has been stacked yet is used as the position where the prints from the transport roller pair  50   k  are to be discharged. By repeating the stacking/transport, the orthogonal transport belt  132  sorts the prints in units of orders. 
     In the printer  10  shown, although the regulating guide  54  is arranged between the transport roller pairs  50   c  and  50   d  immediately upstream the recording unit  56 , the first aspect of the present invention is not restricted to this construction. The regulating guide may be arranged at various positions in the transport path between the recording sheet supplying section and the print discharging section. 
     For example, the regulating guide  54  may be arranged immediately upstream the cutter  40  or the cutter  130  of the printer  10  to suppress bending due to cutting. Further, in the image recording apparatus of the present invention, the number of regulating guides is naturally not restricted to one. It is also possible to arrange a plurality of regulating guides in a single image recording apparatus. 
     Next, the image recording apparatus according to the second aspect of the present invention will be explained referring to  FIG. 1 , and  FIGS. 8A to 14 . 
     Similarly to the various regulating guide units  55  and  55   a  shown in  FIGS. 2A to 7 , the various regulating guide units  155  and  155   a  shown in  FIGS. 8A to 14  are used in the ink jet printer  10  shown in  FIG. 1  instead of the regulating guide units  55  and  55   a . Thus, the explanation of the ink jet printer  10  will be omitted below, and the image recording apparatus according to the second aspect of the present invention will be explained by describing the various regulating guide units  155  and  155   a  shown in  FIGS. 8A to 14  that are applied to the ink jet printer  10 . 
     First, the regulating guide unit  155  shown in  FIGS. 8A to 8C  will be explained. 
       FIGS. 8A through 8C  show schematic views of the regulating guide unit  155  which is used in the ink jet printer  10  shown in  FIG. 1  and comprises the transport roller pair  50   c  including the inclination mechanism  81  which functions as the passage changing means, the regulating guide  154 , and the transport roller pair  50   d , in which  FIG. 8A  is a plan view thereof (i.e., a top view of  FIG. 1 ),  FIG. 8B  is a front view (seen in the same direction as in  FIG. 1 ), and  FIG. 8C  is a side view (as seen from the upstream side with respect to the transport direction for the recording sheet S, and the right-hand side in the figure is the upper side) showing only the regulating guide. To clarify the construction, the transport roller pairs  50   c  and  50   d  are omitted in  FIG. 8C . Further, to clarify the construction, the frames  64   a  and  64   b  described below are omitted in  FIG. 8B . 
     The regulating guide unit  155  shown in  FIGS. 8A to 8C  has the same configuration as the regulating guide unit  55  shown in  FIGS. 2A and 2B  except that the regulating guide unit  155  comprises the regulating guide  154  instead of the regulating guide  54 . Thus, each component of the regulating guide unit  155  that is the same as that of the regulating guide unit  55  is given the same reference numeral, and a detailed explanation thereof is omitted. 
     Basically, the regulating guide  154  comprises two (a pair of) inner variable-width guides  166  and  168  movable in the width direction, two (a pair of) outer variable-width guides  170  and  172  arranged on both sides in the width direction of the inner variable-width guides  166  and  168 , screw shafts  174  and  175 , and guide shafts  176  and  177 . 
     The screw shaft  174  extends in the width direction above the transport plane and is rotatably supported by the frames  64   a  and  64   b . At one end, the screw shaft  174  is connected to a rotation power source (not shown), and is rotatable. The screw shaft  175  extends in the width direction at a position opposed to the screw shaft  174  with the transport plane therebetween and is rotatably supported by the frames  64   a  and  64   b . The screw shaft  175  is connected to a rotation power source (not shown) at one end and is rotatable. The screw shafts  174  and  175  are connected to different rotation power sources, and are independently rotatable. Each of the screw shafts  174  and  175  is a so-called double-end screw shaft having a right-hand thread on one outer side of the center in the axial direction and a left-hand thread on the other outer side of the center in the axial direction. 
     On the other hand, the guide shaft  176  is a bar-like member extending in the width direction above the transport plane and fixed to the frames  64   a  and  64   b . The guide shaft  177  is a bar-like member similar to the guide shaft  176 , and is arranged at a position opposed to the guide shaft  176  with the transport plane therebetween. 
     The inner variable-width guides  166  and  168  are guide members which, when the image recording is performed on the recording sheets S transported in parallel in two lines, regulate the end position of each recording sheet S on the center side in the width direction (hereinafter, this side will be simply referred to as inner side, and the sides opposite thereto will be referred to as outer sides). 
     The inner variable-width guide  166  comprises a guide portion  169  of a C-shaped sectional configuration having a slit-like passage portion (i.e., an inner passage portion)  166   a  through which an end portion of the recording sheet S which is transported in parallel passes and which is open at one end and closed at the other end, and an engagement portion  181  provided under the guide portion  169  (under C-shaped portion). On the other hand, the inner variable-width guide  168  has the same construction as the inner variable-width guide  166 . The inner variable-width guide  168  comprises the guide portion  169  of a C-shaped sectional configuration including a passage portion  168   a  through which an end portion of the recording sheet S passes, and an engagement portion  181  provided under the guide portion  169 . 
     Both the inner variable-width guides  166  and  168  are arranged side by side in the width direction of the transport path for the recording sheet S, with the C-shaped portions being visible in the transport direction and the open ends of the passage portions directed outwards. 
     Both the outer variable-width guides  170  and  172  are guide members which, in the case of the single-line transport, regulate the positions of the end portions in the width direction of a single recording sheet S, and which, in the case of the parallel transport, regulate the positions of the respective outer end portions of two recording sheets S. 
     The outer variable-width guide  170  comprises a guide portion  178  with a substantially E-shaped sectional configuration including slit-like passage portions (i.e., outer passage portions)  170   a  and  170   c  through which an end portion of the recording sheet S (one end portion in the case of the single-line transport, and the outer end portion in the case of the parallel transport) passes and which are open at one end and closed at the other end, with a rib  170   r  being provided therebetween, and an engagement portion  180  provided on the guide portion  178  (on E-shaped portion). On the other hand, the outer variable-width guide  172  has a construction similar to that of the outer variable-width guide  170 . The outer variable-width guide  172  comprises the guide portion  178  with a substantially E-shaped sectional configuration including passage portions  172   a  and  172   c  through which an end portion of the recording sheet S passes, with a rib  172   r  being provided therebetween, and an engagement portion  180  provided on the guide portion  178 . 
     The outer variable-width guides  170  and  172  are both arranged on the outer sides in the width direction of the transport path with the inner variable-width guides  166  and  168  therebetween, with the E-shaped portions being visible in the transport direction, the open ends of the passage portions being directed inwardly, and the two passage portions being stacked together in a direction (hereinafter referred to as a vertical direction) perpendicular to the transport plane for the recording sheet S. Further, the outer variable-width guide  170  is arranged at a position where it is opposed to the inner variable-width guide  166  and paired therewith, and the outer variable-width guide  172  is arranged at a position where it is opposed to the inner variable-width guide  168  and paired therewith. 
     As shown in  FIG. 8B , in the preferred example shown, the inner variable-width guides  166  and  168  and the outer variable-width guides  170  and  172  are configured such that the upstream end portions of their passage portions expand gradually toward the upstream side, thereby enabling the recording sheet S to be inserted into the passage portions easily and reliably. 
     The engagement portion  181  of each of the inner variable-width guides  166  and  168  has a screw hole  181   a  into which the screw shaft  175  is screwed, and a guide hole  181   b  through which a part of the guide shaft  177  is passed while slightly in slide contact therewith. 
     One of the right-hand thread and the left-hand thread of the screw shaft  175  is screwed into the screw hole  181   a  of the inner variable-width guide  166 , and the other thread of the screw shaft  175  is screwed into the screw hole  181   a  of the inner variable-width guide  168 . 
     Further, the inner variable-width guides  166  and  168  are arranged so as to be outwardly spaced apart from the center in the width direction by the same distance. 
     The engagement portion  180  of each of the outer variable-width guides  170  and  172  has a screw hole  180   a  into which the screw shaft  174  is screwed, and a guide hole  180   b  through which a part of the guide shaft  176  is passed while slightly in slide contact therewith. The right-hand thread or the left-hand thread of the screw shaft  174  is screwed into the screw hole  180   a  of the outer variable-width guide  170 , and the other thread of the screw shaft  174  is screwed into the screw hole  180   a  of the outer variable-width guide  172 . 
     Further, the outer variable-width guides  170  and  172  are arranged so as to be outwardly spaced apart from the center in the width direction by the same distance, with the inner variable-width guides  166  and  168  therebetween. 
     Thus, by turning the screw shaft  175 , the inner variable-width guides  166  and  168  move toward and away from each other symmetrically with respect to the center in the width direction according to the turning direction, thus making it possible to adjust the distance between them. Similarly, by turning the screw shaft  174 , the outer variable-width guides  170  and  172  move toward and away from each other symmetrically with respect to the center in the width direction according to the turning direction, thus making it possible to adjust the distance between them. 
     Due to this construction, the distance between the inner variable-width guide  166  and the outer variable-width guide  170  and the distance between the inner variable-width guide  168  and the outer variable-width guide  172  allow adjustment while maintaining the same distance therebetween. 
     In the regulating guide  154  shown, the inner variable-width guides  166  and  168  and the outer variable-width guides  170  and  172  are arranged such that the passage portions  166   a  of the inner variable-width guide  166 , the passage portion  168   a  of the inner variable-width guide  168 , the passage portion  170   a  of the outer variable-width guide  170 , and the passage portion  172   a  of the outer variable-width guide  172  are at the same vertical position. 
     The inner variable-width guides  166  and  168  are fixed at positions lower than the plane connecting the passage portion  170   c  of the outer variable-width guide  170  and the passage portion  172   c  of the outer variable-width guide  172 . 
     That is, in the regulating guide  154 , two passages (i.e., transport paths) are formed in the vertical direction. As shown in  FIGS. 9A and 9B , when performing the parallel transport in two lines, the lower transport path where the inner variable-width guides  166  and  168  are arranged is used, one recording sheet S is regulated in its position in the width direction and undergoes positioning in the width direction by the passage portion  166   a  of the inner variable-width guide  166  and the passage portion  170   a  of the outer variable-width guide  170 , and the other recording sheet S is regulated in its position in the width direction and undergoes positioning in the width direction by the passage portion  168   a  of the inner variable-width guide  168  and the passage portion  172   a  of the outer variable-width guide  172  before being transported to the recording unit  56  on the downstream side. 
     As stated above, the two transport paths for the parallel transport (hereinafter referred to as the parallel paths for the sake of convenience) respectively regulated by the inner variable-width guide  166  and the outer variable-width guide  170  and by the inner variable-width guide  168  and the outer variable-width guide  172  allow width adjustment while maintaining the same width. Thus, at the time of the parallel transport, the regulating guide  154  can simultaneously transport two recording sheet S of the same width. 
     Further, the inner variable-width guides  166  and  168  and the outer variable-width guides  170  and  172  move independently of each other, whereby the width of the parallel paths can be adjusted with a high degree of freedom. Thus, the regulating guide  154  can perform the parallel transport in conformity with the recording sheets S of various sizes (widths). 
     On the other hand, as shown in  FIGS. 10A and 10B , when performing the single-line transport, the upper transport path with no inner variable-width guides  166  and  168  is used; a single recording sheet S is regulated in its position in the width direction and undergoes positioning in the width direction by the passage portion  170   c  of the outer variable-width guide  170  and the passage portion  172   c  of the outer variable-width guide  172  before being transported to the recording unit  56  on the downstream side. 
     By adjusting the distance between the outer variable-width guides  170  and  172 , it is possible to adjust the width of the transport path for the single-line transport (hereinafter referred to as the single-line path for the sake of convenience). As a result, the regulating guide  154  can be adapted to the recording sheets S of various sizes (widths) even in the case of the single-line transport. 
     In the printer  10  shown, the inclination mechanism  81  of the transport roller pair  50   c  arranged on the upstream side of the regulating guide  154  functions as the passage changing means which regulates the vertically arranged transport paths for the recording sheet S, guiding the recording sheet S to the lower transport path for the parallel transport (i.e., the parallel path) where the inner variable-width guides  166  and  168  are used and where the recording sheets S are regulated in their positions in the width direction by the passage portion  166   a  of the inner variable-width guide  166  and the passage portion  170   a  of the outer variable-width guide  170  and by the passage portion  168   a  of the inner variable-width guide  168  and the passage portion  172   a  of the outer variable-width guide  172 , or guiding a single recording sheet S to the upper transport path for the single-line transport (i.e., the single-line path) where the inner variable-width guides  166  and  168  are not used and where the recording sheet S is regulated in its position in the width direction by the passage portion  170   c  of the outer variable-width guide  170  and the passage portion  172   c  of the outer variable-width guide  172 . 
     The inclination mechanism  81  shown in  FIGS. 8A and 8B  has the same configuration as the inclination mechanism  81  shown in  FIGS. 2A and 2B , so the explanation thereof is omitted. Hereinafter, the function of the inclination mechanism  81  of the transport roller pair  50   c  of the regulating guide unit  155  shown in  FIGS. 8A and 8B  as the passage changing means will be explained. 
     As shown in  FIG. 8B  and  FIG. 11A , in the example shown, in the normal state (that is, the state in which the piston  86   a  is not extruded), the inner variable-width guides  166  and  168  and the outer variable-width guides  170  and  172  are arranged such that the parallel path (i.e., the lower transport path where the inner variable-width guides  166  and  168  are used) constitutes the transport path where the recording sheets S are transported by the transport roller pairs  50   c  and  50   d.    
     Thus, as shown in  FIG. 11A , the leading guide  83  which is formed of guide plates parallel to the transport paths where transport is effected by the transport roller pair  50   c  is in the state in which the leading guide  83  guides the recording sheet S into the parallel path; the recording sheets S transported from the transport roller pair  50   c  are guided by the leading guide  83  and pass through the lower parallel path of the regulating guide  154  (formed by the inner variable-width guides  166  and  168  and the outer variable-width guides  170  and  172 ) to be regulated in their positions in the width direction, and are further fed and transported to the transport roller pair  50   d  before being transported to the recording unit  56  (the reference guide  102  thereof) on the downstream side. 
     As shown in  FIG. 11B , when, in this normal state, the solenoid  86  extrudes the piston  86   a , the piston  86   a  pushes the upper portion of the lever  84  toward the downstream side. As described above, the lever  84  is swingably supported at the center by the pin  84   c , so it is inclined through this pushing by the piston  86   a , with its upper portion being on the downstream side and its lower portion on the upstream side. 
     Due to this inclination of the lever  84 , the pin  82   c  on the upper portion of the bracket  82  is pushed toward the downstream side. As stated above, the bracket  82  rotatably supports the driven roller  62 , and is rotatably supported by the driving roller  60  (i.e., the rotation shaft  60   a ), so it is inclined about the driving roller  60  through this pushing with its upper portion being on the upstream side. As shown in  FIG. 11B , as a result of this inclination of the bracket  82 , the driven roller  62  rotatably supported by the elongated holes  82   a  moves toward the upstream side along the driving roller  60 . Further, the leading guide  83  fixed to the bracket  82  is also inclined, and the transport path where transport is effected by the transport roller pair  50   c  and the leading guide  83  is shifted upwards to the upper transport path, i.e., the single-line path where the inner variable-width guides  166  and  168  are not used. 
     Thus, as shown in  FIG. 11B , the recording sheet S transported from the transport roller pair  50   c  in this state is guided by the leading guide  83  and passes through the upper single-line path of the regulating guide  154  (formed by the outer variable-width guides  170  and  172 ) and is regulated in its position in the width direction. Further, the recording sheet S is fed and transported to the transport roller pair  50   d  before being transported to the recording unit  56  (i.e., the reference guide  102  thereof) on the downstream side. 
     In order that the recording sheet S may be reliably transported from the single-line path of the regulating guide  154  to the transport roller pair  50   d , it is possible to provide a guide member for guiding the recording sheet S from the single-line path to the transport roller pair  50   d.    
     In this aspect, the passage changing means for changing to the single-line path and the parallel path is not restricted to the above-described one. It is possible to use various types of other transport passage changing means. 
       FIGS. 12A through 12C  show one embodiment of the regulating guide unit  155   a  comprising another passage changing means, in which  FIG. 12A  is a plan view of the regulating guide unit  155   a , and  FIGS. 12B and 12C  are front views thereof. 
     The regulating guide unit  155   a  shown in  FIGS. 12A to 12C  has the same configuration as the regulating guide unit  155  shown in  FIGS. 8A to 8C  except that the regulating guide unit  155   a  comprises the passage changing means  87  of the regulating guide unit  55   a  shown in  FIGS. 6A to 6C  instead of the inclination mechanism (passage changing means)  81  of the regulating guide unit  155 . Thus, each component of the regulating guide unit  155   a  that is the same as that of the regulating guide unit  155  is given the same reference numeral, and detailed descriptions thereof are omitted. Therefore, different points will be mainly explained. 
     In the passage changing means  87  shown in  FIGS. 12A through 12C , four plate-like leading guides  88  (flappers) for regulating the transport direction of the recording sheet S in the vertical direction are provided at the respective upstream ends of the inner variable-width guides  166  and  168  and the outer variable-width guides  170  and  172 . In this example, the transport roller pairs  50   c  and  50   d  are all rotatably supported by the frames  64   a  and  64   b.    
     The leading guides  88  are of a wedge-like configuration whose thickness gradually decreases in one direction. Proximal ends (the thicker ends) of the leading guides  88  are fixed to the inner variable-width guides  166  and  168  and the outer variable-width guides  170  and  172  by such means as hinges, with their thinner ends (hereinafter referred to as distal ends) being on the upstream side. Thus, the leading guides  88  can be rocked using their proximal ends as a fulcrum. 
     The four leading guides  88  are respectively fixed to the upper portions of the upstream end portions of the inner variable-width guides  166  and  168  and to the upstream end portions of the ribs  170   r  and  172   r  of the outer variable-width guides  170  and  172 . That is, the leading guides  88  are fixed in position over the lower parallel path. 
     The plate-like arms  90  are fixed to the lower surfaces of the portions in the vicinity of the distal ends of the leading guides  88 . The pin  90   a  is fixed to the lower ends of the arms  90 . 
     As shown in  FIG. 12A , the pin  90   a  fixed to the arms  90  extends in the width direction. Specifically, the single pin  90   a  passes through and is engaged with all the arms  90 , that is, the arms  90  fixed to the leading guides  88  of the inner variable-width guides  166  and  168 , the arm  90  fixed to the leading guide  88  of the outer variable-width guide  170 , and the arm  90  fixed to leading guide  88  of the outer variable-width guide  172 , thereby fixing all the arms  90 . 
     The lever  92  is a substantially rectangular plate member whose longitudinal direction is matched with the transport direction and which is swingably supported at the center by the pin  92   c . The lever  92  has at its longitudinal ends the elongated-hole-like notches  92   a  and  92   b . The pin  90   a  fixing the arms  90  is passed through and engaged with the upstream notch  92   a . The pin  92   c  is fixed, for example, to the frame  64   a.    
     The solenoid  86  similar to the one described above is engaged with the downstream side notch  92   b  of the lever  92 . More specifically, the pin  86   b  at the distal end of the piston  86   a  of the solenoid  86  is inserted into and engaged with the downstream notch  92   b  of the lever  92 . 
     Instead of being provided for each of the inner variable-width guides  166  and  168  and the outer variable-width guides  170  and  172 , the solenoid  86  and the lever  92  are only provided one each. 
     Also in the example shown in  FIGS. 12A through 12C , the inner variable-width guides  166  and  168  and the outer variable-width guides  170  and  172  are arranged such that the transport path in which the recording sheet S is transported by the transport roller pairs  50   c  and  50   d  is matched with the parallel path (i.e., the lower transport path where the inner variable-width guides  166  and  168  are used). 
     As shown in  FIG. 12B , in the normal state (that is, the state in which the piston  86   a  is not extruded), the leading guides  88  fixed in position over the lower parallel path as described above are parallel to the transport paths where transport is effected by the transport roller pairs  50   c  and  50   d . Thus, the recording sheets S transported from the transport roller pair  50   c  advance as they are to pass through the lower parallel path of the regulating guide  154  (formed by the inner variable-width guides  166  and  168  and the outer variable-width guides  170  and  172 ) to be regulated in their positions in the width direction, and are further fed and transported to the transport roller pair  50   d  before being transported to the recording unit  56  on the downstream side. 
     As shown in  FIG. 12C , when, in this normal state, the solenoid  86  extrudes the piston  86   a , the piston  86   a  upwardly pushes the downstream side of the lever  92 . As stated above, the lever  92  is swingably supported at the center by the pin  92   c , so the lever  92  is inclined through the pushing by the piston  86   a , with the downstream side thereof being higher and the upstream side thereof lower. 
     As a result of this inclination of the lever  92 , the arms  90  engaged with the pin  90   a  which is engaged with the notch  92   a  formed at the upstream end of the lever  92  move downwards, and the leading guides  88 , with the arms  90  fixed to the lower surfaces of the portions near the distal ends thereof, are inclined with their distal ends lower, thus making the transport path shifted to the upper single-line path. 
     As stated above, the pin  90   a  fixing the arms  90  is engaged with all the arms  90  that are respectively fixed to the leading guides  88  of all of the inner variable-width guides  166  and  168  and the outer variable-width guides  170  and  172 . Thus, by driving the solenoid  86 , the leading guides  88  of all of the inner variable-width guides  166  and  168  and the outer variable-width guides  170  and  172  are inclined downwards. 
     Thus, as shown in  FIG. 12C , in this state, the recording sheet S transported from the transport roller pair  50   c  is guided by the leading guides  88  and passes through the upper single-line transport path of the regulating guide  154  (formed by the outer variable-width guides  170  and  172 ) to be regulated in its position in the width direction and is further fed and transported to the transport roller pair  50   d  before being transported to the recording unit  56  (i.e., the reference guide  102  thereof) on the downstream side. 
     In the example shown, the inner variable-width guides  166  and  168  and the outer variable-width guides  170  and  172  are arranged such that the transport path where transport is effected by the transport roller pairs  50   c  and  50   d  is matched with the parallel path corresponding to the parallel transport, however, this should not be construed restrictively. 
     Taking into account the burden on the recording sheet S, it is desirable for the transport path normally used in the regulating guide  154  to be matched with the transport path where the transport is effected by the transport roller pairs  50   c  and  50   d.    
     Further, in the example shown, although the regulating guide  154  comprises the inner variable-width guides  166  and  168  of a substantially C-shaped sectional configuration to perform the parallel transport in two lines, this should not be construed restrictively. 
     For example, it is also possible to adopt a construction as the regulating guide unit  154   a  shown in  FIG. 13 , in which there are provided an inner variable-width guide  196  of a substantially H-shaped sectional configuration comprising passage portions  196   a  and  196   b  through which the end portions of recording sheets S to be transported in parallel pass, and an inner variable-width guide  198  of a substantially H-shaped sectional configuration having similar passage portions  198   a  and  198   b.    
     In this case, it is possible to perform the parallel transport by using three parallel paths: a parallel path α where the recording sheet passes through the passage portion  170   a  of the outer variable-width guide  170  and the passage portion  196   a  of the inner variable-width guide  196 ; a parallel path β where the recording sheet passes through the passage portion  196   b  of the inner variable-width guide  196  and the passage portion  198   a  of the inner variable-width guide  198 ; and a parallel path γ where the recording sheet passes through the passage portion  198   b  of the inner variable-width guide  198  and the passage portion  172   a  of the outer variable-width guide  172 . 
     As stated above, the inner variable-width guides  196  and  198  and the outer variable-width guides  170  and  172  are capable of moving toward and away from each other symmetrically in the width direction, and the distance between the inner variable-width guide  196  and the outer variable-width guide  170  is the same as the distance between the inner variable-width guide  198  and the outer variable-width guide  172 , so the parallel paths α and γ are parallel paths of the same width, and the parallel path β can be a parallel path whose width is different from that of the parallel paths α and γ. 
     In the example shown, the parallel transport in three lines is possible through the three parallel paths α, β and γ. In this case, the parallel transport in tree lines of the same width is possible. Further, it is also possible to perform the parallel transport in three lines by the parallel paths α and γ of the same width, and the parallel path β of a different width. 
     The mode of the parallel transport is not restricted to the parallel transport in three lines; it is also naturally possible to perform the parallel transport in two lines through two parallel paths selected from the parallel paths α, β and γ. In the case in which the parallel paths α and β or the parallel paths β and γ are selected, it is also possible to perform the parallel transport in two lines on the recording sheets S of different widths. 
     As is apparent from the above description, according to the second aspect of the present invention, in the regulating guide for regulating the position in the width direction of the recording sheet S, there are formed two transport paths in the vertical direction (i.e., the direction perpendicular to the transport plane for the recording sheet S), and the single-line transport, the parallel transport in two lines, three lines, etc. are performed by using these transport paths, so the regulating guide can be easily adapted to a variety of transport modes. 
     Further, since each variable-width guide does not move vertically, it is possible to minimize an error in variable-width guide position attributable to such vertical movement. That is, it is possible to perform positioning on the recording sheet S with high accuracy and to effect proper image recording free from an error in recording position, etc. 
     Further, the inner variable-width guides and the outer variable-width guides are movable independently in the width direction and symmetrically with respect to the central position in the width direction of the transport path, thus making it possible to regulate the transport path with a high degree of freedom in the width direction, whereby it is possible to perform the image recording in conformity with recording media of various sizes (widths). 
     In particular, in the case of the parallel transport, it is possible to set the positions in the width direction of the two parallel paths formed by the inner variable-width guides and the outer variable-width guides paired with each other, symmetrically with respect to the center of the transport path but with a high degree of freedom in the width direction. 
     As described above, the recording unit  56  is arranged on the downstream side of the regulating guide  154  (i.e., the transport roller pair  50   d ). 
     The recording unit  56  comprises the well-known ink jet recording means  100  using an ink jet recording head (hereinafter referred to as a recording head) and the reference guide  102  for regulating the vertical position of the recording sheet S, and performs well-known full-color image recording by ink jet. 
     In the image recording apparatus disclosed in Patent Document 1 and Patent Document 2, the inner guide used for the parallel transport is fixed. Thus, when these image recording apparatus use a line head for the image recording section, the nozzles (that is, the recording elements) situated near the center of the line head are used in a concentrated manner, with the result that as compared with the other nozzles, the deterioration of the nozzles in this region is allowed to progress. 
     In contrast, as described above, in the image recording apparatus of the second aspect of the present invention, the inner guides for effecting positioning on the inner sides of the recording sheet S during the parallel transport are movable in the width direction, with the result that it is possible to set the transport path in the width direction for the recording sheet S in the case of the parallel transport with a high degree of freedom, although the inner sides are moved symmetrically with respect to the center in the width direction. 
     Thus, when the second aspect of the present invention is applied to a line head as the recording unit of the image recording section, the transport path for the recording sheet S at the time of the parallel transport can be changed in the width direction in accordance with the number of times that each nozzle is driven (i.e., the number of times that ink is ejected), the number of prints transported in parallel, the number of prints of each size, etc., thereby leveling out the number of times that each nozzle of the line head is driven. As a result, it is possible to prevent deterioration in image quality due to deterioration in a part of the nozzles, and to achieve improvement in terms of the durability of the line head, thereby elongating the service life of the line head. 
     In the following, an example of such application of the second aspect of the present invention will be described with reference to  FIGS. 14A and 14B . 
       FIGS. 14A and 14B  are explanation views of the operation of the image recording apparatus comprising a line head as the recording unit. Specifically,  FIGS. 14A and 14B  are schematic top views of the recording unit and the regulating guide unit for illustrating the positional relationship between the line head and the transport path for the parallel transport (i.e., the parallel path).  FIG. 14A  shows the regulating guide  154  when the parallel path is set inwardly in the width direction of the transport path in the case of using a line head  150  as the recording unit  56  and the regulating guide unit  155  shown in  FIGS. 8A to 8C  as the regulating guide unit in the ink jet printer  10  shown in  FIG. 1 .  FIG. 14B  shows the regulating guide  154  when the parallel path is set relatively outwardly in the width direction of the transport path in the case of using the line head  150  and the regulating guide unit  155 . The components (members) that are the same as those of the above ink jet printer  10  shown in  FIG. 1  and the regulating guide unit  155  shown in  FIGS. 8A to 8C  are indicated by the same reference numerals, and a detailed explanation thereof will be omitted. 
     In  FIGS. 14A and 14B , a motor  194  is a rotation power source for a screw shaft  174  connected to one end of the screw shaft  174 . Similarly, a motor  195  is a rotation power source for a screw shaft  175  connected to one end of the screw shaft  175 . The motors  194  and  195  are connected to a drive control section  153 . 
     The drive control section  153  controls the operation of the motors  194  and  195  in response to a control signal from the control section  24 , a recording control section  152  described in detail below, etc., and turns the screw shafts  174  and  175 , thereby adjusting the positions of the variable-width guides (i.e., the inner variable-width guides  166  and  168  and the outer variable-width guides  170  and  172 ). 
     A line head  150  performs the image recording by the FWA system described above, and comprises a nozzle line having a maximum recording width in the width direction. The line head  150  is arranged/fixed with the nozzle line being matched with the width direction. 
     The recording control section  152  is connected to the line head  150 , and transmits a drive signal to each recording element of the line head based on the image data to be recorded to control the operation of the line head  150 . Further, the recording control section  152  is capable of storing the number of times that the nozzles of the line head  150  eject ink (hereinafter simply referred to as number of times of ejection). The recording control section  152  determines the positions of the variable-width guides according to the number of times of ejection of the nozzles as stored, and transmits a signal to the drive control section  153  to move the variable-width guides. 
     As stated above, when performing the parallel transport in two lines, the regulating guide  154  is capable of setting the two parallel paths to predetermined positions within the movable range for the variable-width guides, although they are symmetrical with respect to the center in the width direction. 
     An example of the method of setting the parallel paths will be described. At the time of the image recording, the recording control section  152  stores the number of times of ejection of each nozzle of the line head  150 . Then, at the time of next image recording by the parallel transport, the recording control section  152  reads the number of times of ejection of each nozzle as stored. If there are any nozzles or regions involving a large number of times of ejection, the recording control section  152  decides on transport paths where those nozzles or regions are not used. For example, when, in the case of the transport paths for the recording sheet S shown in  FIG. 14A , the number of times of ejection of the nozzles in the region near the center of the line head is larger than the number of times of ejection in the other regions, the recording control section  152  decides on regions other than those shown in  FIG. 14A  for the transport paths for the parallel transport of the recording sheets S, for example, regions corresponding to the outer portions of the line head as shown in  FIG. 14B . The drive control section  153  sets the parallel paths by moving the guides according to positional information on the parallel paths decided upon, that is, the positional information on the guides. 
     As described above, according to the second aspect of the present invention, the positions in the width direction of the parallel paths are set according to the frequency of use of the nozzles of the line head, whereby the frequency of use of each nozzle of the line head is leveled out, and local deterioration of the recording elements is prevented to thereby improve the durability of the line head, with the result that it is possible to maintain a satisfactory ejection performance for the line head as a whole, thereby making it possible to elongate the service life of the line head. 
     The above-described parallel path setting method is only given by way of example, and this embodiment is not restricted to this method. 
     Here, when the image recording is to be performed by the PWA system, that is, when the image recording is to be performed by performing scanning in the width direction with a small recording head (shuttle head) mounted on the carriage (i.e., scanning means), with the transport of the recording sheet S being suspended, it is possible to provide a flashing (that is, blank printing) region between the inner variable-width guides  166  and  168 . 
     In this aspect, similarly to the above described first aspect, it goes without saying that the arrangement positions of the regulating guides and the number of the arranged regulating guides are not limited to the above described example. 
     Next, an image recording apparatus of the third aspect of the present invention will be explained referring to  FIG. 1  and  FIGS. 15A to 20C . 
     Similarly to the various regulating guide units  55  and  55   a  shown in  FIGS. 2A to 7 , the various regulating guide units  255  and  255   a  shown in  FIGS. 15A to 20C  are used in the ink jet printer  10  shown in  FIG. 1  instead of the regulating guide units  55  and  55   a . Thus, the explanation of the ink jet printer  10  will be omitted below, and the image recording apparatus according to the third aspect of the present invention will be explained by describing the various regulating guide units  255  and  255   a  shown in  FIGS. 15A to 20C  that are applied to the ink jet printer  10 . 
     First, the regulating guide unit  255  shown in  FIGS. 15A to 15C  will be explained. 
       FIGS. 15A through 15C  show schematic views of the regulating guide unit  255  which is used in the ink jet printer  10  shown in  FIG. 1  and comprises the transport roller pair  50   c  including the inclination mechanism  81  which functions as the passage changing means, the regulating guide  254 , and the transport roller pair  50   d , in which  FIG. 15A  is a plan view thereof (i.e., a top view of  FIG. 1 ),  FIG. 15B  is a front view (seen in the same direction as in  FIG. 1 ), and  FIG. 15C  is a side view (as seen from the upstream side with respect to the transport direction for the recording sheet S, and the right-hand side in the figure is the upper side) showing only the regulating guide. To clarify the construction, the transport roller pairs  50   c  and  50   d  are omitted in  FIG. 15C . Further, to clarify the construction, the frames  64   a  and  64   b  described below are omitted in  FIG. 15B . 
     The regulating guide unit  255  shown in  FIGS. 15A to 15C  has the same configuration as the regulating guide unit  55  shown in  FIGS. 2A and 2B  except that the regulating guide unit  255  comprises the regulating guide  254  instead of the regulating guide  54  of the regulating ink guide  54 . Thus, each component of the regulating guide unit  255  that is the same as that of the regulating guide unit  55  is given the same reference numeral, and a detailed description explanation thereof is omitted. 
     Basically, the regulating guide  254  comprises a fixed guide  268  fixed at a predetermined position in the width direction, two variable-width guides  270  and  272  arranged on both sides in the width direction of the fixed guide  268 , screw shafts  274  and  275 , and a guide shaft  276 . In the example shown, the fixed guide  268  corresponds to the inner guide, and the variable-width guides  270  and  272  correspond to the outer guides. 
     The screw shafts  274  and  275  extend in the width direction, and are rotatably supported by the frames  64   a  and  64   b . The screw shafts  274  and  275  are respectively turned by separate rotation drive sources (not shown). 
     The screw shaft  274  is a screw shaft having a thread extending from the position of the fixed guide  268  to the position of one frame  64   a . The screw shaft  275  is a screw shaft having a thread extending from the position of the fixed guide  268  to the position of the other frame  64   b . As described below, the screw shafts  274  and  275  are screwed into the variable-width guides  270  and  272 , respectively. 
     The guide shaft  276  is a bar-like member extending in the width direction and fixed to the frames  64   a  and  64   b.    
     The fixed guide  268  is a guide member which, when image recording is performed on the recording sheets S transported in parallel in two lines, regulates the position of the end on the central side with respect to the width direction (hereinafter, this side will be simply referred to as inner side, and the sides opposite thereto will be referred to as outer sides) of each recording sheet S. 
     In the example shown, the fixed guide  268  exhibits a substantially H-shaped sectional configuration, and comprises slit-like passage portions (i.e., inner passage portions)  268   a  and  268   b  through which the inner side end portions of the two recording sheet S transported in parallel pass, with each of the inner passage portions being open at one end and closed at the other end. 
     The fixed guide  268  is fixed at a predetermined position in the width direction of the transport path for the recording sheet S, with the H-shaped section being visible in the transport direction and the open ends of the passage portions  268   a  and  268   b  being directed outwards. 
     The position of the fixed guide  268  is not restricted to the position shown in the drawing. It is possible to adopt a position selected from various positions, such as the center in the width direction, as long as it is between the variable-width guides  270  and  272 . 
     On the other hand, both the variable-width guides  270  and  272  are guide members which, in the case of the single-line transport, regulate the positions of the end portions in the width direction of one recording sheet S, and which, in the case of the parallel transport, regulate the positions of the respective outer end portions of two recording sheets S. 
     The variable-width guide  270  comprises a guide portion  278  of a substantially E-shaped sectional configuration including slit-like passage portions (i.e., outer passage portions)  270   a  and  270   c  through which end portions of the recording sheets S (one end portion in the case of the single-line transport, and the outer end portions in the case of the parallel transport) pass and which are open at one end and closed at the other end, with a rib  270   r  being provided therebetween, and an engagement portion  280  provided on the guide portion  278  (on E-shaped portion). It is arranged on the passage portion  268   a  side of the fixed guide  268 . 
     The other variable-width guide  272  has a construction similar to that of the variable-width guide  270 . The variable-width guide  272  comprises a guide portion  279  of a substantially E-shaped sectional configuration including passage portions  272   a  and  272   c  through which end portions of the recording sheets S pass, with a rib  272   r  being provided therebetween, and an engagement portion  281  provided on the guide portion  279 . The variable-width guide  272  is arranged on the passage portion  268   b  side of the fixed guide  268 . 
     The variable-width guides  270  and  272  are both arranged on either side in the width direction of the fixed guide  268  (i.e., on the outer sides in the width direction of the fixed guide  268 ), with the E-shaped portions being visible in the transport direction, the open ends of the passage portions being directed inwardly, and the two passage portions being stacked together in a direction (hereinafter referred to as the vertical direction) perpendicular to the transport plane for the recording sheet S. 
     In the illustrated example, as a preferable aspect, the central fixed guide  268  and the variable-width guides  270  and  272  are configured such that the upstream end portions of their passage portions expand gradually toward the upstream side such as the variable-width guide  270  shown in  FIG. 15B , thereby enabling the recording sheet S to be inserted into the passage portions easily and reliably. 
     The engagement portion  280  of the variable-width guide  270  has a screw hole  280   a  into which the screw shaft  274  is screwed, a guide hole  280   b  through which one end portion of the guide shaft  275  with no thread is passed while slightly in slide contact therewith, and a guide hole  280   c  through which a part of the guide shaft  276  is passed while slightly in slide contact therewith. 
     On the other hand, the engagement portion  281  of the variable-width guide  272  has a screw hole  281   a  into which the screw shaft  275  is screwed, a guide hole  281   b  through which one end portion of the guide shaft  274  with no thread is passed while slightly in slide contact therewith, and a guide hole  281   c  through which a part of the guide shaft  276  is passed while slightly in slide contact therewith. 
     Thus, by turning the screw shafts  274  and  275 , the variable-width guides  270  and  272  move continuously, respectively, according to the turning direction, toward and away from the fixed guide  268  independently of each other, thus making it possible to continuously adjust the distance between the variable-width guides  270  and  272 , the distance between the variable-width guide  270  and the fixed guide  268 , and the distance between the variable-width guide  272  and the fixed guide  268 . 
     As described below, in the example shown, it is possible, due to the above-described construction, to transport the recording sheets S of various widths by both the single-line transport and the parallel transport, and in the case of the parallel transport, to transport two kinds of recording sheets S of different widths. 
     The regulating guide  254  may be formed without providing the guide shaft  276  by using the portion of the screw shaft  275  having no thread as the guide shaft of the variable-width guide  270  and the portion of the screw shaft  274  having no thread as the guide shaft of the variable-width guide  272 . In this case, it is possible to further simplify the construction of the regulating guide  254 . 
     In the regulating guide  254  shown, the fixed guide  268  and the variable-width guides  270  and  272  are arranged such that the passage portions  268   a  and  268   b  of the fixed guide  268 , the passage portion  270   a  of the variable-width guide  270 , and the passage portion  272   a  of the variable-width guide  272 , are at the same vertical position. 
     The fixed guide  268  is fixed at a position lower than the plane connecting the passage portion  270   c  of the variable-width guide  270  and the passage portion  272   c  of the variable-width guide  272 . 
     That is, in the regulating guide  254 , two passages (i.e., transport paths) are formed in the vertical direction. As shown in  FIGS. 16A and 16B , when performing the parallel transport in two lines, the lower transport path where the fixed guide  268  is arranged is used, one recording sheet S is regulated in its position in the width direction and undergoes positioning in the width direction by the passage portion  268   a  of the fixed guide  268  and the passage portion  270   a  of the variable-width guide  270 , and the other recording sheet S is regulated in its position in the width direction and undergoes positioning in the width direction by the passage portion  268   b  of the fixed guide  268  and the passage portion  272   a  of the variable-width guide  272  before being transported to the recording unit  56  on the downstream side. Each of the passage portions  268   a  and  268   b  of the fixed guide  268  serves as a reference position for the positioning of the recording sheet S in the parallel transport. 
     On the other hand, as shown in  FIGS. 17A and 17B , when performing the single-line transport, in the upper transport path with no fixed guide  268  is used, a single recording sheet S is regulated in its position in the width direction and undergoes positioning in the width direction by the passage portion  270   c  of the variable-width guide  270  and the passage portion  272   c  of the variable-width guide  272  before being transported to the recording unit  56  on the downstream side. 
     As stated above, the variable-width guides  270  and  272  are continuously movable in the width direction independently of each other, so by adjusting the positions of the variable-width guides  270  and  272  to arbitrary positions within their movable ranges, it is possible to handle the recording sheets S of various widths (sizes) regardless of whether it is the single-line transport or the parallel transport that is to be performed. 
     Further, the variable-width guides  270  and  272  are continuously movable in the width direction independently of each other. Thus, if, for example, the recording media to be transported by the parallel transport are the recording sheets S of different widths as shown in  FIGS. 16A and 16B , or the recording sheets S of the same width as shown in  FIGS. 18A and 18B , it is possible to perform the parallel transport simultaneously by respectively adjusting the positions in the width direction of the variable-width guides according to the width of the recording media. 
     In the printer  10  shown, the inclination mechanism  81  of the transport roller pair  50   c  arranged on the upstream side of the regulating guide  254  functions as the passage changing means which regulates the vertically arranged transport paths for the recording sheet S, guiding the recording sheets S to the lower transport path for the parallel transport (hereinafter referred to as parallel path for the sake of convenience), where the fixed guide  268  is used and where the recording sheets S are regulated in their positions in the width direction by the passage portions  268   a  and  268   b  of the fixed guide  268 , the passage portion  270   a  of the variable-width guide  270 , and the passage portion  272   b  of the variable-width guide  272 , or guiding a single recording sheet S to the upper transport path for the single-line transport (hereinafter referred to as single-line path), where the fixed guide  268  is not used and where the single recording sheet S is regulated in its position in the width direction by the passage portion  270   c  of the variable-width guide  270  and the passage portion  272   c  of the variable-width guide  272 . 
     The inclination mechanism  81  shown in  FIGS. 15A and 15B  has the same configuration as the inclination mechanism  81  shown in  FIGS. 2A and 2B , so the explanation thereof is omitted. Hereinafter, the function of the inclination mechanism  81  of the transport roller pair  50   c  of the regulating guide unit  255  shown in  FIGS. 15A and 15B  as the passage changing means will be explained. 
     As shown in  FIG. 15B  and  FIG. 19A , in the example shown, in the normal state (i.e., the state in which the piston  86   a  has not been extruded yet), the fixed guide  268  and the variable-width guides  270  and  272  are arranged such that the parallel path (i.e., the lower transport path where the fixed guide  268  is used) constitutes the transport path where the recording sheets S are transported by the roller transport pairs  50   c  and  50   d.    
     Thus, as shown in  FIG. 19A , the leading guide  83  which is formed of guide plates parallel to the transport paths where transport is effected by the transport roller pair  50   c  is in the state in which the leading guide  83  guides the recording sheets S into the parallel path. The recording sheets S transported from the transport roller pair  50   c  are guided by the leading guide  83  and pass through the lower parallel path of the regulating guide  254  (formed by fixed guide  268  and variable-width guides  270  and  272 ) to be regulated in their positions in the width direction, and are further fed to the transport roller pair  50   d  before being transported to the recording unit  56  (i.e., the reference guide  102  thereof) on the downstream side. 
     As shown in  FIG. 19B , when, in this normal state, the solenoid  86  extrudes the piston  86   a , the piston  86   a  pushes the upper portion of the lever  84  toward the downstream side. As described above, the lever  84  is swingably supported at the center by the pin  84   c , so the lever  84  is inclined through this pushing by the piston  86   a , with its upper portion being on the downstream side and its lower portion on the upstream side. 
     Due to this inclination of the lever  84 , the pin  82   c  on the upper portion of the bracket  82  is pushed toward the upstream side. As stated above, the bracket  82  rotatably supports the driven roller  62 , and is rotatably supported by the driving roller  60  (i.e., the rotation shaft  60   a ), so the bracket  82  is inclined about the driving roller  60  through this pushing with its upper portion being directed to the upstream side. As shown in  FIG. 19B , as a result of this inclination of the bracket  82 , the driven roller  62  rotatably supported by the elongated holes  82   a  moves toward the upstream side along the driving roller  60 . Further, the leading guide  83  fixed to the bracket  82  is also inclined, and the transport path where transport is effected by the transport roller pair  50   c  and the leading guide  83  is shifted upwards to the upper transport path, i.e., the single-line path where the fixed guide  268  is not used. 
     Thus, as shown in  FIG. 19B , the recording sheet S transported from the transport roller pair  50   c  in this state is guided by the leading guide  83  and passes through the upper single-line path of the regulating guide  254  (formed by the variable-width guides  270  and  272 ) and is regulated in its position in the width direction. Further, the recording sheet S is fed and transported to the transport roller pair  50   d  before being transported to the recording unit  56  (i.e., the reference guide  102  thereof) on the downstream side. 
     In order that the recording sheet S may be reliably transported from the single-line path of the regulating guide  254  to the transport roller pair  50   d , it is possible to provide a guide member for guiding the recording sheet S from the single-line path to the transport roller pair  50   d.    
     In the third aspect of the present invention also, the passage changing means for changing from the single-line path to the parallel path is not restricted to the one described above. It is also possible to use various types of other passage changing means. 
       FIGS. 20A through 20C  show one embodiment of the regulating guide unit  255   a  comprising another passage changing means, in which  FIG. 20A  is a plan view of the regulating guide unit  255   a , and  FIGS. 20B and 20C  are front views thereof. 
     The regulating guide unit  255   a  shown in  FIGS. 20A to 20C  has the same configuration as the regulating guide unit  255  shown in  FIGS. 15A to 15C  except that the regulating guide unit  255   a  comprises the passage changing means  87  of the regulating guide unit  55   a  shown in  FIGS. 6A to 6C  instead of the inclination mechanism (passage changing means)  81  of the regulating guide unit  255 . Thus, each component of the regulating guide unit  255   a  that is the same as that of the regulating guide unit  255  is given the same reference numeral, and the detailed explanation thereof is omitted. Therefore, different points will be mainly explained. 
     In the passage changing means  87  shown in  FIGS. 20A through 20C , the plate-like leading guides  88  (flappers) for regulating the transport direction of the recording sheet S in the vertical direction are provided at the respective upstream ends of the fixed guide  268  and the variable-width guides  270  and  272 . In this example, the transport roller pairs  50   c  and  50   d  are all rotatably supported by the frames  64   a  and  64   b.    
     The leading guides  88  are of a wedge-like configuration whose thickness gradually decreases in one direction. The proximal ends (thicker ends) of the leading guides  88  are fixed to the fixed guide  268  and the variable-width guides  270  and  272  by such means as hinges, with their thinner ends (hereinafter referred to as distal ends) being on the upstream side. Thus, the leading guides can be rocked using their proximal ends as a fulcrum. 
     The leading guides  88  are respectively fixed to the upper portion of the upstream end portion of the fixed guide  268  and to the upstream end portions of the ribs  270   r  and  272   r  of the variable-width guides  270  and  272 . That is, the leading guides  88  are fixed in position over the lower parallel path. 
     The plate-like arms  90  are fixed to the lower surfaces of the portions in the vicinity of the distal ends of the leading guides  88 . The pin  90   a  is fixed to the lower ends of the arms  90 . 
     As shown in  FIG. 20A , the pin  90   a  fixed to the arms  90  extends in the width direction. Specifically, the single pin  90   a  passes through and is engaged with all the arms  90 , that is, the arm  90  fixed to the leading guide  88  of the fixed guide  268 , the arm  90  fixed to the leading guide  88  of the variable-width guide  270 , and the arm  90  fixed to leading guide  88  of the variable-width guide  272 , thereby fixing all the arms  90 . 
     The solenoid  86  similar to the one described above is engaged with the downstream notch  92   b  of the lever  92 . More specifically, the pin  86   b  at the distal end of the piston  86   a  of the solenoid  86  is inserted into and engaged with the downstream notch  92   b  of the lever  92 . 
     Instead of being provided for each of the central fixed guide  268  and the variable-width guides  270  and  272 , the solenoid  86  and the lever  92  are only provided one each. 
     Also in the example shown in  FIGS. 20A through 20C , the fixed guide  268  and the variable-width guides  270  and  272  are arranged such that the transport path in which the recording sheet S are transported by the transport roller pairs  50   c  and  50   d  is matched with the parallel path (i.e., the lower transport path where the fixed guide  268  is used). 
     As shown in  FIG. 20B , in the normal state (i.e., the state in which the piston  86   a  is not extruded), the leading guides  88  fixed in position over the lower parallel path as described above are parallel to the transport path where transport is effected by the transport roller pairs  50   c  and  50   d . Thus, the recording sheets S transported from the transport roller pair  50   c  advance as they are to pass through the lower parallel path of the regulating guide  254  (formed by the fixed guide  268  and the variable-width guides  270  and  272 ) to be regulated in their positions in the width direction, and are further fed to the transport roller pair  50   d  before being transported to the recording unit  56  on the downstream side. 
     As shown in  FIG. 20C , when, in this normal state, the solenoid  86  extrudes the piston  86   a , the piston  86   a  upwardly pushes the downstream side of the lever  92 . As stated above, the lever  92  is swingably supported at the center by the pin  92   c , so the lever  92  is inclined through the pushing by the piston  86   a , with the downstream side thereof being higher and the upstream side thereof lower. 
     As a result of this inclination of the lever  92 , the arms  90  engaged with the pin  90   a  which is engaged with the notch  92   a  formed at the upstream end of the lever  92  move downwards, and the leading guides  88 , with the arms  90  fixed to the lower surfaces of the portions near the distal ends thereof, are inclined with their distal ends lower, thus making the transport path shifted to the upper single-line path. 
     As stated above, the pin  90   a  fixing the arms  90  is engaged with all the arms  90  that are respectively fixed to the leading guides  88  of all of the fixed guide  268  and the variable-width guides  270  and  272 . Thus, by driving the solenoid  86 , the leading guides  88  of all of the fixed guide  268  and the variable-width guides  270  and  272  are inclined downwards. 
     Thus, as shown in  FIG. 20C , in this state, the recording sheet S transported from the transport roller pair  50   c  is guided by the leading guides  88  and passes through the upper single-line transport path of the regulating guide  254  (formed by the variable-width guides  270  and  272 ) to be regulated in its position in the width direction and is further fed and transported to the transport roller pair  50   d  before being transported to the recording unit  56  (i.e., the reference guide  102  thereof) on the downstream side. 
     In the example shown, although the fixed guide  268  and the variable-width guides  270  and  272  are arranged such that the transport path where transport is effected by the transport roller pairs  50   c  and  50   d  is matched with the parallel path for the parallel transport, this should not be construed restrictively. 
     Taking into account the burden on the recording sheet S, it is desirable for the transport path normally used in the regulating guide  254  to be matched with the transport path where transport is effected by the transport roller pairs  50   c  and  50   d.    
     Further, in the example shown, while the variable-width guides  270  and  272  (outer guides) which are provided outwardly in the width direction are provided with two passage portions arranged in the vertical direction, and two transport paths are provided in the vertical direction, this should not be construed restrictively. For example, it is also possible to provide three transport paths in the vertical direction. 
     For example, it is also possible to adopt a construction in which three passage portions are vertically arranged in each of the variable-width guides  270  and  272  and in which two second inner guides having on both sides in the width direction thereof passage portions for the recording sheet S are provided at positions which are between the fixed guide  268  (inner guide) and the variable-width guides in the width direction and which do not interfere with the transport plane of the fixed guide  268 , whereby it is possible to perform the parallel transport in three lines. Due to this construction, it is possible to perform three modes of transport. The three modes of transport include the single-line transport using solely the variable-width guides  270  and  272 , the parallel transport in two lines using the fixed guide  268 , and the parallel transport in three lines using the two second inner guides. 
     It is also possible for at least one of the above two second inner guides to be movable in the width direction. 
     As is apparent from the above description, according to the third aspect of the present invention, in the regulating guide for regulating the positions in the width direction of the recording sheet S, the pair of outer guides are continuously movable in the width direction independently of each other in the width direction with respect to the inner guide fixed at a predetermined position therebetween, so the width of the parallel path and that of the single-line path can be set arbitrarily. Thus, it is possible to handle the recording sheets S of various widths (sizes) in both the single-line transport and the parallel transport. In the case of the parallel transport, it is possible to simultaneously transport the recording sheets S of different widths in parallel. Further, by providing movement means for moving the pair of outer guides, there is no need for a user to manually move the guides, thus making it possible to easily handle the recording sheets S of various widths (sizes). 
     As a preferred aspect, in the regulating guide for regulating the positions in the width direction of the recording sheet S in the illustrated example, there are formed a plurality of transport paths in the vertical direction (i.e., the direction perpendicular to the transport plane for the recording sheet S), and the single-line transport and the parallel transport are performed by using these transport paths, so the regulating guide can be easily adapted to a variety of transport modes, thereby making it possible to achieve substantial improvement in degree of freedom in terms of recording modes for an image recording apparatus utilizing the parallel transport. 
     Similarly, in the example shown, the guide serving as a positional reference (the fixed guide  268  in the example shown) is fixed in position and does not move, so it is possible to eliminate the influence of an error in guide position attributable to such movement, that is, it is possible to perform positioning on the recording sheet S with high accuracy and to effect proper image recording free from an error in recording position, etc. 
     As described above, the recording unit  56  is arranged on the downstream side of the regulating guide  254  (i.e., the transport roller pair  50   d ). 
     The recording unit  56  comprises the well-known ink jet recording means  100  using an ink jet recording head (hereinafter referred to as recording head) and the reference guide  102  for regulating the vertical position of the recording sheet S, and performs well-known full-color image recording by ink jet. 
     In the regulating guide  254  of the printer  10  shown, the inner guide (the fixed guide  268  in the example shown) is fixed at a predetermined position in the width direction, and the pair of outer guides (the variable-width guides  270  and  272  in the example shown) are continuously movable in the width direction independently of each other, however, this should not be construed restrictively. For example, it is also possible to adopt a construction in which the inner guide and one outer guide are continuously movable in the width direction independently of each other and in which the other outer guide is fixed, or a construction in which all the three guide members are continuously movable in the width direction independently of each other. In brief, it is only necessary for at least two of the inner guide and the pair of outer guides to be continuously movable in the width direction independently of each other. This makes it possible to arbitrarily set the width of the transport path, so even in the case of the recording sheets S of different widths, it is possible to transport them in parallel simultaneously. Further, it is possible to handle the recording sheets S of various widths easily. 
     Further, while in the above example, the regulating guide  254  comprises a plurality of transport paths in the vertical direction (i.e., the direction perpendicular to the recording paper transport plane), with switching being possible between the single-line transport and the parallel transport in two or three lines or more, this should not be construed restrictively. It is also possible to adopt a construction in which only one transport path is provided in the vertical direction. In this case, it is possible for the regulating guide to be adapted solely to the parallel transport as in Patent Document 1 or to be adapted to both the parallel transport and the single-line transport, with the inner guide being vertically movable as in Patent Document 2. 
     Although the image recording apparatus of the present invention has been explained in detail above, the present invention is not limited to the above embodiments, and various modifications and improvements are of course possible without departing from the gist of the present invention.