Abstract:
The image coding apparatus includes conveying unit configured to convey a roll-shaped recording medium, a recording head adapted to record an image on the recording medium, a guide member configured for guiding the recording medium, and a cutting unit configured to cut the recording medium, wherein the guide member is provided with at least one friction member on a surface of the guide member, the at least one friction member configured to come into contact with the recording medium.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an image recording apparatus such as a printer, a copying apparatus or a facsimile, having a cutting unit for cutting a roll-shaped recording medium. 
   2. Description of the Related Art 
   There are already commercially available image recording apparatuses having a printer function for recording an image on a recording medium based on image information, composite apparatuses having a facsimile function, an original reading function, an image pickup function and the like in addition to the printer function, and systems constituted by connecting such image recording apparatuses to host equipment such as computers. 
   The image recording apparatus employed in such apparatuses sometimes performs image recording on a roll-shaped recording medium such as a recording paper or a recording film. In the present application, a “rolled sheet” may be defined as a roll-shaped recording medium, and further the material thereof is not limited to a paper or a plastic sheet. 
   An image recording apparatus for image recording on a roll-shaped recording medium may include a cutting unit (cutting mechanism) for cutting the recording medium. As for the cutting unit, there is already known an apparatus for cutting the recording medium by a pair of cutting blades. Such cutting unit is used, for example in an image recording apparatus for image recording on a roll-shaped recording medium conveyed in the apparatus, for cutting the recording medium after recording into a predetermined length at a discharge thereof. Such cutting units may include a type utilizing a knife-shaped blade, a type utilizing a pair of blades of which one is an elongated fixed blade and the other is a rotatable circular blade, and a type utilizing a pair of rotatable circular blades. 
   Such image recording apparatuses are constructed so as to store a roll-shaped recording medium, to record image data by a scanning (reciprocating) motion of a recording head, and to cut the recording medium after image data recording into each page. More specifically, the recording medium is supplied to a platen when image data are entered. Above the platen, there is provided a recording head for executing a recording by ink discharge under a reciprocating motion. An image of a line is recorded on the recording medium by a scanning motion of the recording head, and, after the recording medium is advanced by a predetermined distance by a conveying roller, an image of a line is recorded again by a scanning motion of the recording head. Thus an image is recorded on an entire page by repeating the recording of a line image and the conveying of the recording medium by a predetermined distance. Then a recorded portion of the recording medium is guided to a sheet discharge member provided outside the apparatus, and is cut into each page by the cutting unit. The recording medium cut into each page is stored on a stacking member provided below the sheet discharge member. 
   In the case of cutting the recording medium in the serial operations as described above, the cutting operation is executed from a lateral end of the recording medium to the other lateral end thereof, and, in case the recording medium has a large width, an already cut portion of the recording medium may be displaced downwards by the weight thereof in the course of the cutting operation. For this reason, the recording medium may not be cut linearly but may show a curved cut edge or may be torn off at an end portion of the cut edge. 
   In order to prevent such a situation, Japanese Patent Application Laid-Open No. H05-147385 discloses a structure for pressing, at the cutting of the recording medium, a position thereof at a sheet discharge side with respect to a cutting line by a lower end of a cover, thereby, preventing a displacement of the recording medium and enabling an exact cutting of the recording medium. 
   Also Japanese Patent Application Laid-Open No. H05-254194 discloses a structure of extending, at the cutting of the recording medium, a pressing belt for pressing the recording medium along with the movement of a cutter unit, thereby, preventing a displacement of the recording medium and enabling an exact cutting of the recording medium. 
   Moreover, Japanese Patent Application Laid-Open No. H11-78140 discloses a structure for pressing, at the cutting of the recording medium, a lateral edge at the cutting start side, thereby, preventing a displacement of the recording medium and enabling an exact cutting of the recording medium. 
   However the structure disclosed in Japanese Patent Application Laid-Open No. H05-147385 is associated with several technical drawbacks. For instance, the pressing member has to be separated from the recording medium at the conveying motion thereof and to be pressed thereon at the cutting operation. Moreover, the pressing member, formed by a cover, provides a bulky and complex apparatus with an elevated cost. Also, since the recorded surface (image bearing surface) of the recording medium has to be pressed, the recorded image may be damaged in case of recording a frameless image. 
   Also, the structure disclosed in Japanese Patent Application Laid-open No. H05-254194 is associated with a drawback. In particular, since the recorded surface has to be pressed with the pressing belt, the recorded image may be damaged in case of recording a frameless image. 
   Additionally, the structure disclosed in Japanese Patent Application Laid-open No. H11-78140 has some disadvantages. For instance, it requires a mechanism which separates a pressing member from the recording medium when it is conveyed and which presses the recording medium from above at the cutting operation of the recording medium. Such structure is associated with drawbacks of requiring a complex mechanism with an increased cost, and therefore, since the recorded surface has to be pressed, the recorded image may be damaged in case of recording a frameless image. 
   SUMMARY OF THE INVENTION 
   The present invention has been made in consideration of the technical situation explained in the foregoing. An aspect of the present invention is to provide an image recording apparatus capable of avoiding damage to the recording surface in case of recording a frameless image, without resulting in bulkiness or complication of the apparatus. Another aspect of the present invention is also to provide an image recording apparatus capable of exactly cutting a recording medium along a cut line and preventing a downward displacement of an already cut portion by the weight thereof in the course of a cutting operation. The present invention further provides an image recording apparatus capable of preventing the recording medium from being torn off near an end of the cutting operation. 
   The aforementioned aspects and features can be attained, according to the present invention, by an image recording apparatus including conveying unit configured to convey a roll-shaped recording medium, a recording head adapted to record an image on the recording medium, a guide member configured for guiding the recording medium, and a cutting unit configured to cut the recording medium, wherein the guide member is provided with at least one friction member configured to come into contact with the recording medium. 
   The present invention allows to provide an image recording apparatus capable, in cutting a roll-shaped recording medium conveyed by the conveying unit, of preventing a damage on a recording surface when recording a frameless image, while preventing the apparatus from becoming bulky or complicated. Also there is provided an image recording apparatus capable of exactly and easily cutting the recording medium along a cut line while preventing, in the course of a cutting operation, an already cut portion from being displaced downwards by a weight thereof and also preventing that the recording medium is torn off near an end of the cutting operation. Further features and advantages of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings). 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic perspective view of an exemplary embodiment of an image recording apparatus according to the present invention; 
       FIG. 2  is a schematic vertical cross-sectional view showing an exemplary configuration of cutting unit from  FIG. 1 ; 
       FIG. 3  is a schematic perspective view showing an exemplary sheet discharge member from  FIG. 1 , together with the cutting unit; 
       FIG. 4  is a schematic cross-sectional view showing a state where a recording medium is conveyed along a sheet discharge member and a leading end of the recording medium is positioned at a linear portion of the sheet discharge member, according to an aspect of the present invention; 
       FIG. 5  is a schematic cross-sectional view showing a state where a recording medium is conveyed along a sheet discharge member and a leading end of the recording medium is positioned at a curved portion of the sheet discharge member, according to an aspect of the present invention; and 
       FIG. 6  is a schematic cross-sectional view showing a state where a recording medium conveyed from a recording part is cut and discharged, according to an aspect of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   In the following, embodiments of the present invention will be explained with reference to the accompanying drawings, in which like reference characters designate the same or similar parts throughout the drawings. 
     FIG. 1  is a schematic perspective view of an exemplary embodiment of an image recording apparatus of the present invention. Referring to  FIG. 1 , a carriage  40  supporting a recording head  1  which functions as recording unit is supported as to be capable of a reciprocating motion along a rail  2  serving as a scanning guide, provided in a main body of the apparatus. A roll-shaped recording medium (rolled sheet)  101 , supplied in a recording part, is conveyed by a pair of conveying rollers  3  constituting a conveying unit. The rolled sheet  101  is a continuous recording medium constituted of a roll-shaped recording paper or plastic sheet, and is not limited to a paper. 
   In the recording part, a platen  4  is provided for guiding and supporting the recording medium  101  from a rear side. The platen  4  serves also as a chassis of the main body of the apparatus, and secures a gap between the recording head  1  and the recording medium  101 . When an image of a line is recorded in the recording part by a forward or reverse scanning motion of the recording head  1 , the recording medium  101  is advanced with the conveying rollers  3  in a direction A by a predetermined pitch, and the recording head  1  is moved again to execute an image recording of a next line. An image is thus recorded on an entire page by repeating these operations. A recorded portion  101   a  of the recording medium is conveyed to the exterior of the main body of the apparatus, by guiding with a sheet discharge member (guide member)  7 . In the present embodiment, upon completion of the image recording, the recording medium  101  is conveyed by the conveying rollers  3  to a cutting position at a downstream side of the platen  4  in the conveying direction. 
   At the cutting position, there is provided a cutting unit (cutting mechanism)  100  for cutting the recording medium  101  along a cut line  103 . When the image recording is completed, the recording medium  101  is conveyed by the conveying rollers  3  to a predetermined cutting position. Then, in response to a cutting operation signal, a motor  30  is activated, thereby, driving a circular blade unit  120 , capable of moving in a direction B along a fixed blade  6  of a fixed blade unit  110 , from a cutting start position at the left-hand side to a cutting end position  120   a  at the right-hand side. In this operation, the rolled sheet  101  is cut along the cut line  103 , thereby separating a recorded portion  101   a  at the downstream side in the conveying direction (indicated by an arrow A). The cut line  103  coincides with a blade edge of the fixed blade  6 . 
   At the downstream side of the cutting unit  100  in the conveying direction, there is not provided paired sheet discharge rollers for pinching the sheet (recording medium) nor any other pinching unit. Therefore, the recorded portion  101   a  cut into a sheet drops by the weight thereof onto a stacking member  8  provided below the sheet discharge member  7 , and is thus discharged. An upper surface of the fixed blade  6  is set at such a height somewhat lower than a sheet passing surface of the platen  4  (an upper surface in the illustrated example), and an upper surface of the sheet discharge member  7  is set at such a height somewhat lower than the upper surface of the fixed blade  6 . That is to say, these members are so set as to become lower in succession, in the conveying direction of the recording medium  101 . 
     FIG. 2  is a schematic vertical cross-sectional view showing an exemplary configuration of the cutting unit  100  in  FIG. 1 . Referring to  FIG. 2 , the fixed blade unit  110  is constructed by fixing a linear fixed blade  6  on a fixed frame  5  mounted on the platen  4 . The fixed blade  6  is fixed on an upper surface of the fixed frame  5  by a double-stick tape, an adhesive or a spot welding along a widthwise direction of the recording medium  101 . A circular blade unit  120  is mounted on a movable support member  50 , mounted movable along a guide portion of the fixed frame  5  and along the widthwise direction of the recording medium  101 , and a circular blade holder  20  is replaceably mounted on the circular blade unit  120 . 
   The circular blade holder  20  has a cylindrical shape (see also  FIG. 1 ), and accommodates therein a circular blade  24 , having a disk shape and provided with a blade along the periphery thereof, in rotatable manner. The circular blade holder  20  is provided, on a bottom face thereof, with an aperture for permitting the blade of the circular blade  24  to protrude. On a shaft member  29 , for supporting the circular blade  24 , a bearing  27  biased toward the right-hand side by a coil spring  28  is axially slidably fitted. On a cylindrical surface of the bearing  27 , the circular blade  24  is positioned and supported by a pinching member  26 . The circular blade  24  is positioned and supported as to assume an illustrated position with respect to the distal edge of the fixed blade  6 . More specifically, the distal edge of the fixed blade  6  is in contact with a proximity of an edge on a surface of the circular blade  24 . In the present embodiment, when the recording medium  101  is cut along the cut line  103 , the recording medium  101  is pressed onto the upper surface of the fixed blade  6  by an O-ring  25 . The O-ring  25  rolls on the recording medium  101  by a frictional force caused by such pressing, thereby rotating the circular blade  24 . 
     FIG. 3  is a schematic perspective view showing an exemplary sheet discharge member  7  from  FIG. 1 , together with the cutting unit  100 . Referring to  FIGS. 1 and 3 , the sheet discharge member  7  is provided at a downstream side of the cut line  103  on the recording medium  101 , in the conveying direction, and serves as a guide member in conveying the recording medium  101  from the recording part to the exterior of the main body of the apparatus. In the present embodiment, the sheet discharge member  7  also serves as a cover member for covering the recording medium stored as a wound roll. The sheet discharge member  7  is provided, on an upper surface thereof, with a linear portion  7   a  constituting a flat surface over a predetermined length in the conveying direction, and with a curved portion  7   b  curved downwards in a downstream portion in the conveying direction. The curved portion  7   b  is provided, along the widthwise direction of the recording medium  101 , with friction members  11  ( 11   a ,  11   b ,  11   c  and  11   d ). 
   The friction members  11  are constituted of plural friction members  11   a ,  11   b ,  11   c  and  11   d , which are fixed with predetermined gaps along the widthwise direction of the recording medium  101 . That is to say, the friction members  11  are provided partially on the curved portion  7   b , along the widthwise direction of the recording medium. These friction members  11  ( 11   a ,  11   b ,  11   c ,  11   d ) are provided for causing a frictional force on the recording medium  101  in a cutting operation thereof, and are formed by a material of a higher frictional coefficient than in the sheet discharge member  7 . 
   The sheet discharge member  7  can be formed, for example, of a stainless steel plate, a steel plate or a hard plastic material. On the other hand, the friction members  11  can be formed, for example, of a plate-shaped or sheet-shaped material of a relatively high frictional coefficient, such as a rubber-like elastomer, a plastic material, a leather, a synthetic leather or a cloth. Also for increasing the frictional coefficient, there may be employed a surface treatment (painting or plating) or a irregularity formation (such as knurling or napping). 
     FIGS. 4 and 5  are schematic vertical cross-sectional views showing states where the recording medium  101  is conveyed along the sheet discharge member  7 , wherein  FIG. 4  shows a state where a leading end of the recording medium is positioned on the linear portion  7   a  of the sheet discharge member, and while  FIG. 5  shows a state where a leading end of the recording medium is positioned on the curved portion  7   b  of the sheet discharge member. Referring to  FIGS. 1 to 5 , the recording medium  101  is conveyed, at an image recording, by the conveying rollers  3  intermittently with a predetermined pitch, along the conveying direction. As the recording medium  101  is rolled prior to the recording, the leading end thereof is conveyed in a curled state on the sheet discharge member  7 . 
   In the present embodiment, when the leading end of the recording medium is positioned on the linear portion  7   a  of the sheet discharge member  7 , only little frictional force is generated between the leading end of the recording medium  101  and the sheet discharge member  7 , whereby the recording medium  101  is not trapped at the leading end thereof by the sheet discharge member  7  nor is lifted from the platen  4 . On the other hand, when the leading end of the recording medium  101  is positioned on the curved portion  7   b  in the downstream portion of the sheet discharge member  7  as shown in  FIG. 5 , the leading end of the recording medium  101  comes into contact with the friction members  11  ( 11   a ,  11   b ,  11   c ,  11   d ) provided at predetermined spacing along the widthwise direction. 
   These friction members  11 , being positioned on the curved portion  7   b , have a surface inclined by an angle α from the conveying direction (indicated by an arrow A) of the recording medium  101 . Consequently, the frictional force acting between the leading end of the recording medium  101  and the friction members  11  is significantly reduced, whereby the recording medium  101  is not trapped at the leading end thereof by the friction members  11  ( 11   a ,  11   b ,  11   c ,  11   d ) nor is lifted from the platen  4 . 
     FIG. 6  is a schematic vertical cross-sectional view showing a state where the recording medium, conveyed from the recording part, is cut and discharged. Referring to  FIGS. 1 to 6 , after an image recording on an entire page, the recording medium  101  is conveyed by the conveying rollers  3  to a predetermined cutting position. In the cutting position, the circular blade unit  120  is driven with respect to the fixed blade unit  110 , from left to right along an arrow B, whereby the recording medium  101  is cut along the cut line  103  by the fixed blade  6  and the circular blade  24 . In a prior image recording apparatus, in case the recording medium  101  has a large size such as 1.0 m 2  (A0 size) or 1.5 m 2  (B0 size) or larger, an already cut portion of the recording medium  101  is displaced downwards by a weight thereof, even in the course of a cutting operation. 
   In the present embodiment, however, the friction members  11  ( 11   a ,  11   b ,  11   c  and  11   d ) come into contact with the recording medium  101  in the cutting operation thereof, thereby generating a frictional force between the recording medium  101  and the friction members  11 . The frictional force functions so as to prevent the already cut portion of the recording medium  101  from displacing downwards by the weight thereof, in the course of the cutting operation. Therefore, the recording medium  101  does not show a downward displacement of the already cut portion in the course of the cutting operation, and can therefore be easily and linearly cut. 
   The recorded portion  101   a  cut into a sheet is discharged onto the stacking member  8  provided below the sheet discharge member  7 . In this operation, the recorded portion  101   a  cut into a sheet is discharged by the weight thereof and a pushing force of the recording medium  101  remaining in the main body of the apparatus. In the present embodiment, since the friction members  11   a ,  11   b ,  11   c  and  11   d  are provided in predetermined partial areas on the sheet discharge member  7 , the frictional force between the recorded and cut portion  101   a  and the friction members  11   a ,  11   b ,  11   c  and  11   d  may be so selected as to be smaller than a sum of the weight of the recorded and cut portion  101   a  and the pushing force of the recording medium  101 . By selecting the frictional force in this manner, the recorded and cut portion  101   a  can be securely discharged without remaining on the sheet discharge member  7 . 
   In the embodiment explained in the foregoing, since the friction members  11   a ,  11   b ,  11   c  and  11   d  are provided within a predetermined widthwise range on a surface of the sheet discharge member  7  on which the recording medium  101  passes, the frictional force generated between the recording medium  101  and the friction members allows to prevent a displacement of the recording medium  101  by the weight thereof (downward displacement) in the course of a cutting operation. It is thus rendered possible to avoid situations where the cut edge is curved and deviated from the cut line  103  or the recording medium is torn off in an end portion of the cut edge, thereby enabling to cut the recording medium  101  easily and linearly. 
   Also since the friction members  11   a ,  11   b ,  11   c  and  11   d  are provided within a predetermined widthwise range of the sheet discharge member  7 , the frictional force generated between the recorded and cut portion  101   a  and the friction members  11  does not become excessively large and the recorded and cut portion  101   a  can be securely discharged without remaining on the sheet discharge member  7 . Also since the utilized frictional force is generated between the rear surface of the recording medium  101  and the friction members  11 , the recording medium  101  can be securely cut without damaging the recorded image even in case of recording a frameless image. Also as the friction members  11  are positioned in the curved portion  7   b  of the sheet discharge member  7 , the leading end of the recording medium is not trapped by the friction members  11  at the image recording on the recording medium  101 , which can be exactly conveyed in a stable state. 
   The above-described embodiment provides an image recording apparatus including conveying unit  3  for conveying a roll-shaped recording medium, a recording head  1  for recording an image on the recording medium conveyed by the conveying unit, a sheet discharge member  7  for guiding the recording medium, after the image recording, to the exterior, and cutting unit  100  for cutting the recording medium conveyed by the conveying unit, wherein friction members  11   a ,  11   b ,  11   c ,  11   d  positioned along a widthwise direction are provided on a surface, for conveying the recording medium  101 , of the sheet discharge member  7 , whereby a frictional force is generated between the friction members  11  and the recording medium  101  to prevent a damage on a recording surface in case of recording a frameless image without resulting in bulkiness or complication of the apparatus, and also to prevent a downward displacement of an already cut portion of the recording medium by the weight thereof in the course of a cutting operation thereby enabling easy and exact cutting along the cut line, and further to prevent that the recording medium is torn off in the end portion of the cutting operation. 
   Also as the friction members  11  are provided in the curved portion  7   b  curved downward from the conveying direction on the sheet discharge member, the leading end of the recording medium  101  is not trapped in the conveying operation thereof by the friction members  11 , whereby the recording medium can be exactly conveyed in a more stable state. Also as the friction members  11  are partially provided in the widthwise direction of the sheet discharge member  7 , the cut recording medium can be securely discharged without remaining on the sheet discharge member  7 . 
   The foregoing embodiment has been explained by an image recording apparatus of serial type in which an image is recorded under a displacement of the recording head  1  along the recording medium  101 , but the present invention is applicable also to and effective likewise in an image recording apparatus of line type in which an image is recorded only by a sub scanning operation of advancing the recording medium in the conveying direction. Also the present invention is applicable to and effective in not only an ink jet image recording apparatus in which an image is formed by discharging ink from a recording head, but also image recording apparatuses of other types such as thermal transfer type, thermal type, laser beam irradiation type or a wire dot type. Furthermore, the present invention is applicable regardless of a number or a type of the recording head, such as a case of utilizing only one recording head and a case of utilizing plural recording heads different in color or density. 
   Furthermore, the present invention is applicable not only to a single image recording apparatus, but also is widely applicable to and similarly effective in an apparatus executing an image recording based on image information for example an image recording apparatus in a composite equipment such as a copying apparatus, a facsimile apparatus or a pickup image recording apparatus, or an image recording apparatus as an output equipment of a composite system such as a computer system. 
   This application claims the benefit of Japanese Patent Application No. 2005-024827, filed Feb. 1, 2005, which is hereby incorporated by reference herein.