Image forming apparatus

Abstract

An image forming apparatus includes a paper feed station from which sheets can be fed from a plurality of roll sheets only by placing the roll sheets in the station, a recording station for recording desired images on the sheets, and a processing station for delivering the sheets on which the images are recorded. The recording station includes a platen roller and a driving pinch roller for pushing and conveying a fed sheet while the sheet is drawn by suction by a suction chamber, a carriage unit for recording an image on the sheet on the suction chamber while moving along the sheet, and a pair of paper delivery rollers for delivering the sheet on which the image is recorded. The processing station includes a table on which the delivered sheets can be sequentially stacked in a predetermined position, and a biasing spring for biasing the pivotal distal end portion of the table.

What is claimed is:  
     
       1. An image forming apparatus comprising first and second sheet roll holding units capable of simultaneously setting a plurality of sheet rolls formed by winding a plurality of sheets having different widths into rolls on an upper surface of said apparatus, 
       wherein said first sheet roll holding unit rotatably holds a widest sheet roll of the plurality of sheet rolls, and said second sheet roll holding unit rotatably holds all others of the plurality of sheet rolls substantially in series with each other such that the sheet rolls held by said second sheet roll holding unit are parallel to the widest sheet roll held by said first sheet roll holding unit and at least partially overlap with said widest sheet roll in a sheet widthwise direction.  
     
     
       2. An apparatus according to  claim 1 , wherein said first sheet roll holding unit is arranged closer to an operation side of said image forming apparatus than said second sheet roll holding unit. 
     
     
       3. An apparatus according to  claim 1 , wherein a joint portion where the sheets fed from said first and second sheet roll holding units join is formed between said first and second sheet roll holding units, and a conveyance path extends from said joint portion so as to guide the sheets fed to said joint portion to an image recording unit for performing image formation processing. 
     
     
       4. An image forming apparatus comprising: 
       flanges detachably attached to both ends of a sheet roll formed by winding a sheet into a roll; and  
       a roller on which said flanges can be placed so that the sheet roll is rotatably supported, wherein said roller controls rotation of the sheet roll so as to feed the sheet.  
     
     
       5. An apparatus according to  claim 4 , wherein said roller comprises a positioning portion which engages with  one of said flanges of the sheet roll and positions the sheet roll in a direction of a width of the sheet roll. 
     
     
       6. An apparatus according to  claim 4 , wherein said roller comprises a paper feed roller for feeding a sheet fed from the sheet roll, and flange receivers formed in two ends of said paper feed roller. 
     
     
       7. An image forming apparatus for forming an image on a sheet fed from a sheet roll formed by winding a sheet into a roll, comprising: 
       a pair of conveyor rollers for pinching and conveying the sheet fed from the sheet roll; and  
       a holding unit arranged in at least one of said conveyor rollers to position and hold the sheet roll.  
     
     
       8. An image forming apparatus for forming an image on a sheet having a downstream end portion by using a recording device, comprising: 
       a platen positioned opposite to said recording device, said platen having a Plurality  plurality of small holes, and said platen being arranged to draw by suction and hold the sheet through said plurality of small holes; and  
       a conveyor, arranged upstream of said small holes of said platen in a sheet conveyance direction, for pushing and conveying the sheet in the sheet conveyance direction, and  
       wherein said recording device starts recording of an image only when the downstream end portion of the sheet reaches the recording device.  
     
     
       9. An apparatus according to  claim 8 , wherein said conveyor conveys the sheet while contacting the sheet on substantially a  the same level as said platen through openings formed in said platen. 
     
     
       10. An image forming apparatus for forming an image on a sheet by using a recording device, comprising: 
       a platen positioned opposite to said recording device to draw by suction and hold the sheet through a plurality of small holes;  
       a conveyor, arranged upstream of said small holes of said platen in a sheet conveyance direction, for pushing and conveying the sheet in the sheet conveyance direction; and  
       a sheet roll positioned upstream of said conveyor in the sheet conveyance direction, said sheet roll being arranged to wind the sheet such that a recorded surface of the sheet faces outward.  
     
     
       11. An apparatus according to  claim 8 , further comprising a sheet guide path positioned upstream of said conveyor in the sheet conveyance direction, said sheet guide path being capable of holding the sheet with a recorded surface of the sheet facing outward in a non-recording mode. 
     
     
       12. An image forming apparatus comprising: 
       a stay fixed to a frame of a main body of said image forming apparatus;  
       a platen fixed to said stay;  
       a recording device for recording an image on a sheet conveyed on said platen; and  
       a guide fixed to said frame to hold said recording device.  
     
     
       13. An apparatus according to  claim 8 , wherein said platen has a sheet conveying surface having a low friction coefficient. 
     
     
       14. An apparatus according to  claim 12 , wherein said platen has a sheet conveying surface having a low friction coefficient. 
     
     
       15. An apparatus according to  claim 8 , wherein said platen comprises a plurality of platens continuously arranged along a sheet widthwise direction. 
     
     
       16. An apparatus according to  claim 12 , wherein said platen comprises a plurality of platens continuously arranged along a sheet widthwise direction. 
     
     
       17. An apparatus according to  claim 12 , wherein said platen comprises a material having substantially a  the same thermal expansion coefficient as said stay. 
     
     
       18. An image forming apparatus comprising: 
       a plurality of sheet roll holding units capable of holding a plurality of sheet rolls formed by winding a plurality of sheets into rolls;  
       guide paths extending from said sheet roll holding units and having a joint portion at which sheets fed from said sheet rolls  the guide paths join;  
       a sheet conveyor, provided downstream of said joint portion of said guide paths, for pinching and conveying sheets passing through said joint portion by making an urging member act on said sheets; and  
       a holding member for holding said urging member so that said urging member is brought into contact with and  or separated from said sheet conveyor, said holding member having a guide surface which guides said sheets fed from said sheet rolls to said joint portion in a direction of said sheet conveyor.  
     
     
       19. An apparatus according to  claim 18 , wherein said holding member comprises a plurality of holders rockingly held by a bar-like support member, and wherein sleeves rotatably fitted on said support member are arranged between said holders. 
     
     
       20. An apparatus according to  claim 18 , wherein at least one of said guide paths extending from said sheet roll holding units includes an elastic member arranged in opposition to said guide surface of said holding member so as to urge said sheets passing through said joint portion. 
     
     
       21. An image forming apparatus for forming an image on a sheet conveyed along a sheet conveyance path, comprising: 
       a carriage for holding a recording device for recording an image on the sheet, said carriage moving said recording device in a direction crossing said sheet conveyance path when performing image recording and retracting said recording device from said sheet conveyance path when in a stand by mode;  
       a sheet sensor arranged on said carriage to detect information relating to the sheet prior to image recording; and  
       a control device for controlling conveyance of the sheet and movement of said carriage, and  
       wherein said sheet sensor is arranged upstream of said recording device in a sheet conveyance direction and closer to said sheet conveyance path than a retracting position of said recording device, so as to oppose the sheet.  
     
     
       22. An apparatus according to  claim 21 , wherein said control device controls conveyance of the sheet based on an output from said sheet sensor. 
     
     
       23. An image forming apparatus comprising: 
       a feeding device for simultaneously feeding a plurality of sheets arranged at predetermined intervals in a sheet widthwise direction;  
       a recording device for forming images on the sheets; and  
       a carriage for reciprocatingly moving said recording device in a direction crossing a sheet conveyance direction,  
       wherein image formation is simultaneously performed by said recording device on all of the plurality of sheets during one recording movement of said carriage based on file information of images to be formed on the sheets.  
     
     
       24. An image forming apparatus comprising: 
       a feeding device for feeding a sheet to a recording unit;  
       a recording device for performing a recording operation to record an image on the sheet in said recording unit;  
       a carriage for reciprocating said recording device a distance not less than a width of the sheet in a direction perpendicular to a sheet conveyance direction;  
       a control device for controlling recording of the image onto the sheet by moving said carriage based on file information containing image recording information and cut position information and in synchronism with conveyance of the sheet; and  
       a sheet cutting device for cutting the sheet on which the image is recorded,  
       wherein when the sheet is not to be cut, the sheet is conveyed a length L (L>0) based on the image recording information and in synchronism with reciprocation of said carriage, and when the sheet is to be cut, the sheet is conveyed a length α (0<α,<L) based on the cut position information, while the recording operation is temporarily stopped, so that a cut position of the sheet opposes said sheet cutting device, the sheet is cut and conveyed a length L−α, and the recording operation is restarted.  
     
     
       25. An image forming apparatus comprising: 
       a feeding device for feeding a plurality of sheets to a recording unit;  
       a recording device for performing a recording operation to record images on the sheets in said recording unit;  
       a carriage for reciprocating said recording device a distance not less than a width of the sheets in a direction perpendicular to a sheet conveyance direction;  
       a control device for controlling recording of images onto the sheets by moving said carriage based on file information containing image recording information and cut position information and in synchronism with conveyance of the sheets; and  
       a sheet cutting device for cutting the sheets on which the images are recorded,  
       wherein when the sheets are not to be cut, the sheets are intermittently conveyed based on the image recording information and in synchronism with reciprocation of said carriage, and when a selected one of the sheets is to be cut, only the selected sheet is conveyed a predetermined length based on the cut position information, while the recording operation is temporarily stopped, so that only a cut position of the selected sheet opposes said sheet cutting means  device, the selected sheet is cut, the sheets are conveyed a predetermined length, and the recording operation is restarted.  
     
     
       26. An apparatus according to  claim 24 , further comprising: 
       a movement control device for retracting said carriage to a standby position when a sheet is to be cut; and  
       a protecting unit for covering said recording device in the standby position.  
     
     
       27. An apparatus according to  claim 25 , further comprising: 
       a movement control device for retracting said carriage to a standby position when a sheet is to be cut; and  
       a protecting unit for covering said recording device in the standby position.  
     
     
       28. An image forming apparatus comprising: 
       a conveyor for conveying, in forward and backward directions, a sheet fed from a roll sheet formed by winding the sheet into a roll;  
       a recording device for recording an image on the sheet while said conveyor conveys the sheet in the forward and backward directions;  
       a sheet cutter for performing a cut operation to cut the sheet on which the image is recorded; and  
       a suction device arranged to suck the sheet toward a platen located to face the recording device by applying a negative pressure to the sheet, and to remove dust produced in said apparatus during and after the cut operation.  
     
     
       29. An image forming apparatus having an upper surface, the image forming apparatus comprising: 
       a roll support mechanism for setting a plurality of sheet rolls formed by winding sheets into rolls on said upper surface of said apparatus, wherein  
       said roll support mechanism comprises a plurality of roll support portions arranged substantially linearly in a direction of a width of the sheet, and  
       said sheet roll is placed across arbitrary ones of said plurality of roll support portions to allow a sheet roll having an arbitrary width to be set to an arbitrary position on an array line of said roll support portions.  
     
     
       30. An apparatus according to  claim 29 , wherein each of said roll support portions comprises a paper feed roller for rotating the sheet roll, and a support roller device for rotatably supporting the sheet roll. 
     
     
       31. An apparatus according to  claim 30 , wherein said support roller device comprises a support roller mechanism capable of rotatably supporting a first end of the sheet roll and controlling rotation of the sheet roll, and a support roller for rotatably supporting a second end of the sheet roll. 
     
     
       32. An apparatus according to  claim 31 , wherein said support roller mechanism comprises a support roller for rotatably supporting one end of the sheet roll to control a rewind of the sheet roll, a reverse motor for controlling rotation of said support roller, and a clutch capable of transmitting a driving force of said reverse motor to said support roller. 
     
     
       33. An apparatus according to  claim 30 , further comprising a coupling mechanism for one of  simultaneously and selectively rotating said paper feed rollers of said plurality of roll support portions independently of each other. 
     
     
       34. An apparatus according to  claim 30 , wherein said coupling mechanism comprises a detecting circuit capable of detecting set positions and set conditions of the sheet rolls, and said image forming apparatus further comprises a display for displaying the set positions and the set conditions of the sheet rolls based on an output detection signal from said detection circuit. 
     
     
       35. An apparatus according to  claim 29 , further comprising a conveyance guide for guiding the sheet in a predetermined direction when the sheet roll supported by said roll support mechanism is at least one of  fed and rewound, said conveyance guide being arranged in a position outside a conveyance path of the sheet. 
     
     
       36. An image forming apparatus comprising first and second sheet roll holding units setting a first sheet roll and at least one second sheet roll formed by winding a plurality of sheets on an upper side of said apparatus, 
       
         said first sheet roll holding unit rotatably holding the first sheet roll, and said second sheet roll holding unit rotatably holding the second sheet roll such that the second sheet roll held by said second sheet roll holding unit is parallel to the first sheet roll held by said first sheet roll holding unit and at least partially overlap with said first sheet roll in a sheet widthwise direction. 
       
     
     
       37. An apparatus according to  claim 36  wherein said first sheet roll and second sheet roll have different widths, respectively. 
     
     
       38. An image forming apparatus comprising: 
       
         a recording device for recording an image on a sheet having a downstream end portion;  
       
       
         a platen having a plurality of holes through which the sheet is drawn and held by suction of the sheet on the platen when the image is recorded on the sheet by the recording device; and  
       
       
         a conveyor arranged upstream of the holes of said platen in a sheet conveyance direction, for pushing and conveying the sheet in the sheet conveyance direction,  
       
       
         wherein said recording device starts recording of the image when the downstream end portion of the sheet reaches the recording device. 
       
     
     
       39. An image forming apparatus comprising: 
       
         a recording device for recording an image on a sheet;  
       
       
         a platen having a holding part and a plurality of holes through which the sheet is drawn and held by suction of the sheet on the platen when the image is recorded on a part of the sheet between the holding part and the recording device, by the recording device;  
       
       
         a first conveyor arranged upstream of the holding part of said platen in a sheet conveyance direction, for pushing and conveying the sheet in the sheet conveyance direction; and  
       
       
         a second conveyor arranged downstream of the holding part of said platen in a sheet conveyance direction for conveying the sheet in the sheet conveyance direction,  
       
       
         wherein said recording device starts recording of the image on the part of the sheet between the holding part and the recording device, before the sheet conveyed by the first conveyor in the sheet conveying direction reaches the second conveyor. 
       
     
     
       40. An image forming apparatus comprising: 
       
         a recording device for recording an image on a sheet;  
       
       
         a platen having a plurality of holes through which the sheet is drawn and held by suction of the sheet on the platen when the image is recorded on the sheet by the recording device;  
       
       
         a conveyor arranged upstream of the holes of said platen in a sheet conveyance direction, for conveying the sheet in the sheet conveyance direction; and  
       
       
         a sheet roll positioned upstream of said conveyor in the sheet conveyance direction, said sheet roll being arranged to wind the sheet such that a recording side of the sheet faces outward in a roll state. 
       
     
     
       41. An apparatus according to  claim 40  wherein said conveyor includes a pinch roller and a platen roller for pinching the sheet therebetween and conveying the sheet to the recording device; and 
       
         a swingable pinch holder for rotatably supporting the pinch roller, the pinch holder having an arcuated surface on which the sheet is slid and along which the sheet is guided so that the sheet is bent in an opposite direction from a rolled direction of the sheet roll. 
       
     
     
       42. An apparatus according to  claim 41  wherein said pinch holder is selectively swung to allow the pinch roller to be in contact with the sheet or to be apart from the sheet. 
     
     
       43. An apparatus according to  claim 41  wherein the arcuated surface of said pinch holder is positioned upstream of the pinch roller in the sheet conveyance direction. 
     
     
       44. An image forming apparatus comprising: 
       
         a recording device for recording an image on a sheet;  
       
       
         a conveyor for conveying, in forward and backward directions, the sheet fed from a roll sheet formed by winding the sheet into a roll;  
       
       
         a sheet cutter for performing a cut operation to cut the sheet on which the image is recorded; and  
       
       
         a platen including a suction chamber having a platen board, and a suction device for creating a negative pressure in the suction chamber to suck the sheet toward the platen board by applying a negative pressure to the sheet through the platen board, and to suck dust produced in the image forming apparatus into the suction chamber during and after the cut operation. 
       
     
     
       45. An apparatus according to  claim 44  wherein said sheet cutter includes a fixed blade extending in a sheet widthwise direction and a movable blade which is moved along the fixed blade to cut the sheet between the fixed and movable blades. 
     
     
       46. An apparatus according to  claim 44  wherein said suction chamber includes a stay on which said sheet cutter is attached. 
     
     
       47. An apparatus according to  claim 44  which comprises a pair of paper delivery rollers arranged downstream of the sheet cutter and conveying the sheet with the sheet pinched between the delivery rollers, wherein when the sheet is cut by the sheet cutter, a portion of the sheet upstream of a cut portion is drawn by the suction device and held to the platen board by the suction force, and a downstream portion of the sheet is pinched between the delivery rollers. 
     
     
       48. An apparatus according to  claim 44  which comprises a carriage which is moved in a sheet widthwise direction for reciprocating the recording device a distance not less than a width of the sheet in the sheet widthwise direction; and 
       
         a control device for controlling recording of the image onto the sheet by moving said carriage based on file information containing image recording information and cut position information and in synchronism with conveyance of the sheet,  
       
       
         wherein while the recording operation is temporarily stopped, the sheet is conveyed a predetermined length based on the cut position information so that only a cut position of the sheet opposes said sheet cutter, the sheet is cut at the cut position, the sheet is conveyed a predetermined length, and then the recording operation is restarted. 
       
     
     
       49. An image forming apparatus comprising: 
       
         a recording device having a recording area in which an image is recorded on a sheet fed from a sheet roll formed by winding the sheet;  
       
       
         a sheet cutter for performing a cutting operation of the sheet on which the image has be recorded; and  
       
       
         a platen including a suction device for sucking the sheet toward the platen by a suction force and for sucking to remove dust generated in the image forming apparatus by the cutting operation. 
       
     
     
       50. An apparatus according to  claim 49  wherein said sheet cutter is disposed downstream of the recording area of the recording device in a sheet conveyance direction. 
     
     
       51. An apparatus according to  claim 49  which comprises a conveyor for conveying the sheet in a direction opposite to the sheet conveyance direction, and wherein said suction device is operative for sucking the sheet toward the platen while the sheet is conveyed in the direction opposite to the sheet conveyance direction by the conveyor.