Sheet feeding or delivering – Feeding – Separator and conveyor
Reexamination Certificate
2001-02-23
2003-04-22
Skaggs, H. Grant (Department: 3651)
Sheet feeding or delivering
Feeding
Separator and conveyor
C271S109000, C271S121000, C271S124000, C271S127000
Reexamination Certificate
active
06550759
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a paper feeding method using a feed roller for winding and feeding a recording material at the top from a storage section in which a plurality of recording materials are stacked on each other, a paper feeder used with the paper feeding method, and a recording apparatus comprising the paper feeder. The invention also relates to an auxiliary roller placed in the paper feeder.
Some recording apparatuses, for example, some printers comprise a detachable paper feed tray (paper tray). The paper feed tray is removed from the printer and a plurality of print sheets (cut sheets) stacked on each other are stored in the paper feed tray, then the paper feed tray is placed again in the printer. To place the paper feed tray in the printer, for example, the paper feed tray is inserted into the printer horizontally from the front of the printer to the depth thereof.
A feed roller is placed at a distance from the front end top print sheet on the attached paper feed tray. When print sheet is fed, it is displaced to the feed roller side by a hopper and is brought into contact with and pressed against the feed roller. Then, as the feed roller is rotated, the top print sheet is wound around the feed roller and is transported.
If a predetermined number or less of print sheets are place in the paper feed tray, the feed roller is placed at a position where it does not come in contact with the print sheet placed in the paper feed tray when the paper feed tray is placed in the printer. However, a larger number of print sheets than the predetermined number of sheets may be placed in the paper feed tray. If the paper feed tray is placed in the printer in this state, some print sheets may come in contact with the feed roller. Since the feed roller is joined to a drive motor, it is configured so as not easily to rotate freely. Therefore, if the paper feed tray is inserted into the printer and placed therein with a print sheet in contact with the feed roller, the sheet of the print sheet in contact with the feed roller may be blocked by the feed roller which does not rotate, and may be bent, wrinkled, or broken in some cases.
On the other hand, a separation pad is placed in the proximity of the downstream side in the paper transport direction of the paper feed tray. The separation pad is configured so that it can be advanced to or retreated from the feed roller.
When paper is fed (namely, when the top print sheet is taken out from the paper feed tray, is wound around the feed roller, and is fed into a transport roller downstream from the feed roller), the separation pad is pressed against the feed roller for clamping the fed print sheet with the feed roller, and if print sheets below the top sheet are about to be transported together with the top sheet, the separation pad separates the top print sheet from the print sheets therebelow. The print sheets below the top sheet separated stop on the separation pad (for example, in the vicinity of the contact center point between the separation pad and the feed roller; i.e., a nip point).
In contrast, at the print (record) time (namely, when printing is executed on transported a print sheet in a print (record) section), the separation pad is placed at a distance from the feed roller for lightening transport resistance (back tension) imposed on the transport roller placed downstream from the feed roller and improving the transport accuracy and the record quality.
However, the rear end part of the top print sheet is still wound around the feed roller during the printing, thus if the top print sheet is transported with the separation pad at a distance from the feed roller, the print sheets below the top sheet on the separation pad may be dragged with the top sheet and be transported to the print section overlapping the top sheet.
Particularly, in a printer having a feeding path shaped roughly like U on side view, which will be hereinafter referred to simply as U-shaped feeding path, where fed print sheet makes almost half a round of the feed roller and is sent in an opposite direction to the direction in which the print sheet is taken out from the paper feed tray, the U-shaped feeding path essentially has a large back tension and to lighten the back tension as much as possible, the feed roller is also rotated together with the transport roller at the print time. Thus, if printing on the top print sheet proceeds and the rear end part of the top sheet is released from being wound around the feed roller, the print sheets below the top sheet on the separation pad may come in contact with the rotating feed roller and be fed.
To prevent such overlap sheet feeding, an auxiliary roller (idle roller) coming in contact with the separation pad at a distance from the feed roller can be placed, thereby sandwiching the top print sheet and the print sheets below the top sheet on the separation pad between the auxiliary roller and the separation pad.
However, if the top print sheet is sandwiched between the auxiliary roller and the separation pad there is a problem of an increase in back tension because of the resistance. Particularly, the U-shaped feeding path described above essentially h as a large back tension and thus it is not preferred that the back tension produced by the auxiliary roller is added.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to prevent overlap sheet feeding of print sheets without increasing back tension.
In order to achieve the above object, according to the present invention, there is provided a method of feeding a recording material, comprising the steps of:
providing a feeder, which includes:
a storage section, in which a plurality of recording materials are stacked;
a feed roller, for feeding a top one of the recording materials in the storage section by rotating forwardly;
a transport roller, for transporting the fed recording material by rotating forwardly, the transport roller being rotatable reversely;
an abutment driver, for moving the storage section between an abutment position and a separated position, the abutment position at which the recording materials are abutted onto the feed roller, the separated position being separated from the feed roller; and
a separator, provided with an abutment part, the separator being movable between an abutment position and a separated position, the abutment position at which the abutment part is abutted onto the feed roller to separate the top one of the recording material from a subsequent recording material, the separated position at which the abutment part is separated from the feed roller;
moving the abutment driver and the separator to the respective abutment position;
rotating the feed roller and the transport roller forwardly until a leading end of the fed recording material fitted on the transport roller is transported therefrom by a first predetermined length which is not less than a feeding path length between a leading end of the recording material stacked in the storage section and an abutment center point of the separator and the feed roller;
stopping the rotations of the feed roller and the transport roller;
moving the abutment driver and the separator to the respective separated positions; and
rotating the transport roller reversely by a predetermined rotation amount which corresponds to a second predetermined length which is not less than the first predetermined length.
In this configuration, the rotations of the feed roller and the transport roller are stopped, the separator is at the abutment position and thus the top recording material is fed and on the other hand, the subsequent recording materials stop in the vicinity of the abutment center point of the separator and the feed roller.
Subsequently, as the transport roller is reversely rotated, the top recording material is returned through the feed roller to the storage section. The subsequent recording materials in the vicinity of the abutment center point of the separator and the feed roller are returned together with the top recording material by the intimate co
Kawakami Kazuhisa
Komuro Kiyoto
Kotaka Toshikazu
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