JP3849245B2 - Document feeder - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus that performs reading while conveying an original along a document conveying path curved in a U-shape, and more particularly, to an original conveying apparatus that performs reading while suppressing fluttering of the original in a reading unit.
[0002]
[Prior art]
An apparatus for reading an image of an original while conveying an original along a U-shaped curved original conveyance path is used for an image reading apparatus of a facsimile apparatus or an image forming apparatus. There is an advantage that it can be configured. In the image reading apparatus, the document tray and the discharge tray are arranged so as to overlap each other, and the document transport path connecting both trays is formed in a substantially U shape. A large-diameter conveying roller is disposed inside the turning portion of the document conveying path curved in the U-shape, and the reading unit is located at a position where the nip action by the roller is not performed in the downstream portion of the roller. Is provided. A white plate for shading is arranged in the reading unit so as to face the platen glass, and an optical system member for image reading is arranged on the back side of the platen glass so as to press the image surface of the document against the platen. The reading operation is performed while moving in the state.
[0003]
[Problem to be Solved by the Invention]
However, as described above, in an apparatus that performs reading while sliding the image surface of the document on the platen glass, when the document used for reading is written in pencil or when correction fluid is applied to the document surface, etc. The correction liquid may be transferred to the platen glass and soil the platen glass. In the apparatus in which the document conveying path is configured in a substantially U-shape, the document is conveyed while being forced to bend, so that foreign matters such as eraser dust and paper dust that adhere to the document are easily peeled off. There's a problem. In addition, when paper dust and other foreign matters released from the original document are collected in the upstream part of the reading unit, it may move to the platen glass following the movement of the original document and adhere to the reading unit. There is a problem that reading information of an image becomes unclear. Further, the image reading portion of the document is provided in a portion that is not regulated by the conveyance roller device, and thus the back end portion of the document may flutter at the moment when the document is out of the nip of the conveyance roller device. There is a problem that the quality of the read image is deteriorated.
[0004]
The present invention solves the problems of the conventional apparatus as described above, and provides an apparatus that guides an original so as not to slide on the platen glass and prevents the original from fluttering at the reading unit. The purpose is that.
[0005]
[Means for Solving the Problems]
The present invention relates to a document conveying apparatus configured to pass a document that is separated and fed from a document tray one by one through a reading unit via a U-turn unit.
A recess provided between the reading unit and the immediately preceding document transport roller and opening in the document transport surface, an inclined surface formed on a side wall on the downstream side in the document transport direction of the recess, and along the inclined surface An elastic film arranged as described above, and a white film for shading attached to the facing surface of the reading unit,
A base portion which is one end portion of the elastic film is fixed to the bottom surface of the recess, and the other end portion of the elastic film is attached so as to protrude toward an upstream end portion of the white film for shading. It is characterized by.
[0006]
By configuring as described above and pressing the original toward the surface facing the platen glass by the elastic film, it is possible to prevent the original from fluttering and to prevent the image reading quality from deteriorating. In addition, since the image surface of the document is guided without sliding on the platen glass, the platen glass is not contaminated, and foreign matter released from the document can be stored in a recess provided upstream of the reading unit. It is possible to prevent such foreign matters from moving to the platen glass. Furthermore, by attaching the base portion of the elastic film to the recess, the fixing action of the film can be performed satisfactorily, and the elasticity of the front end portion of the film can be effectively exhibited. Since the leading end portion of the elastic film protrudes to the portion immediately before the upstream end portion of the white film for shading, the leading end portion of the elastic film extends to the portion immediately before the position where the image of the original is read. Since the sheet is pressed against the opposite surface of the platen glass, the trailing edge of the document does not flutter.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The document conveying device of the present invention will be described according to the example shown in the drawings. FIG. 1 shows the configuration of a document transport unit 10 according to the present invention. A portion of a reading unit 20 that separates documents set on a document tray 7 one by one and arranges them corresponding to a platen glass 21 is shown. The image is read when the document passes. The document transport unit 10 is provided with a mechanism that presses a pickup roller 11 for taking out a document from the document tray 7 only when the document is fed, and a sheet separating device including a feed roller 12 and a retard roller 13 at a downstream portion thereof. Are arranged and conveyed in the document conveyance path 5. The document conveying path 5 is configured to be bent in a substantially U shape. A conveying roller 15 is disposed at a turning portion of the curved path, and pressure rollers 16 and 17 disposed with respect to the conveying roller 15 are used. The document P is conveyed while being pressed against the conveyance roller.
[0008]
A reading unit 20 is provided downstream of the conveying roller 15, and a platen glass 21 and a shading white film (hereinafter referred to as a white film) 22 are opposed to each other so as to sandwich the passage of the original P, and a predetermined interval is provided. The image P is read by a reading device disposed under the platen glass 21, and the document P that has passed through the reading unit is discharged via the discharge roller device 18. A recess 23 is provided in the upstream portion of the reading unit 20 so that when the document is bent by the conveyance roller 15, paper dust and other foreign matters separated from the paper can be accommodated in the recess 23. Although configured, the width, depth, etc. of the recess can be arbitrarily set as long as the action can be satisfactorily performed. The base of the elastic film 25 is fixed to the bottom of the recess 23 using a set screw 27 and a double-sided tape 26, and the end 25 a of the elastic film 25 is attached to the tip of the white film 22. An extension is provided up to a close position to guide the document.
[0009]
The elastic film 25 can be any plastic film. For example, when a PET (polyethylene terephthalate) film having a thickness of about 0.1 to 0.2 mm is used, the original is turned into a white film. The operation of guiding toward the user can be performed satisfactorily. In addition, a film member or sheet-like material made of any material may be used as long as it performs the same function, but the material has a property of being strongly charged by friction with paper. Is not appropriate. In addition to the force that the elastic film 25 presses against the guide member on the document transport path, the paper used for general copying, as well as the tracing paper, is relatively thin and has a low waist. Even when weak paper is used, it is necessary to set it so that it can easily pass through the reading unit. However, when the PET film having a thickness of 0.1 to 0.2 mm is used, it is sufficient. It is possible to satisfy that requirement. Then, by disposing the leading end of the elastic film having the above-described properties so as to reach the upstream end of the white film 22, the trailing end of the document is separated from the nip portion of the roller. Until the end of the elastic film is passed, the back end of the document can be held so that it does not flutter.
[0010]
The recess 23 and the elastic film 25 arranged at the lower part of the turning portion of the document conveying path are configured as described in detail in FIG. Since a force in the pulling direction is applied by moving, it is required to ensure that the base can be fixed. Therefore, in this embodiment, the base portion of the elastic film 25 can be satisfactorily fixed and held by using the double-sided tape 26 and the set screw 27, but any other fixing means is used. be able to. In this embodiment, as will be described later, since the image surface of the document does not slide on the platen glass 21, the focus of image reading of the reading device is set at a position close to the surface of the white film 22. .
[0011]
In the document guide unit, when the leading end of the document is separated from the nip portion of the transport roller 15 and the pressure roller 17, the document guide unit comes into contact with the inclined surface of the elastic film 25 and is guided to the reading position along the elastic film. The white film 22 is slid and guided by the leading end portion 25a, and the reading operation is performed by the reading device at the portion of the platen glass 21. The elastic film 25 presses the original toward the white film until the leading end of the original is nipped by the discharge roller device and tension is applied to the original at the upstream and downstream portions of the reading unit. Then, the image reading is continued in a state where a certain tension is applied by the roller device in the upstream / downstream section. Even when the rear end portion of the document is separated from the nip portion by the conveying roller, the end portion of the elastic film 25 presses the document toward the white film, so that the back end portion of the document There is no sticking, and the document is prevented from vibrating in the reading unit, so that the image reading operation can be performed in a stable state.
[0012]
The document conveying apparatus configured as described above can be provided in an image reading apparatus as shown in FIG. The document conveying device 1 shown in FIG. 3 can be configured by being incorporated in a facsimile machine or a copying machine. In the reading device 30 arranged corresponding to the document conveying device 1, the document moving to the upper surface of the frame 31 is used. A platen glass 21 for reading the image and a platen glass 32 for fixing and setting the document are arranged. Inside the frame, there is provided a full rate carriage 33 for holding the lamp 34 and the mirror m1, and a half rate carriage 35 having two mirrors m2 and m3. The two carriages are connected to a drive pulley 36, It is driven by 36a. The drive pulley 36a is configured to have a half diameter with respect to the drive pulley 36, and an image of a document is displayed via two carriages 33 and 35 driven via wires or timing belts 37 and 37a. The read light information is imaged on a photoelectric conversion element 39 such as a CCD via a lens 38 and output from the CCD 39 as an electrical signal.
[0013]
When an original is set on the platen glass 32 in the reading device 30, the two carriages 33 and 35 perform an image reading operation while being moved by a distance corresponding to the length of the original. When the original is read using the function of the original conveying device 1, the two carriages are fixed at the positions drawn by the phantom lines on the left side of the figure, and the image is read by the platen 21. Make an action. The two reading methods can be arbitrarily selected. For example, a reading device can be selected by inputting using a button on the control panel of the device. It is also possible to automatically select the operation of the reading device by setting the document on the document tray of the document conveying device, setting the document on the platen 32, or the like.
[0014]
In the example shown in FIG. 3, the document conveying unit 10 of the document conveying device 1 is disposed on one side of the frame, and the discharge tray 8 is integrally provided on the cover 6 corresponding to the platen glass 32. . Further, a document tray 7 is disposed above the discharge tray 8, and the document is transported along a U-shaped document transport path provided in the document transport section, and an image is read during document transport. In addition, the two trays are arranged vertically so that the area occupied by the apparatus does not increase. Further, in the document conveying device, the roller members disposed in the document conveying unit 10 are respectively incorporated in the upper frame 2 and the intermediate frame 3, and the two frames are swung through the fulcrum 4, thereby It deals with opening the conveyance path and checking the equipment.
[0015]
【The invention's effect】
The apparatus of the present invention is configured as described above, and an elastic film for pressing the document against the opposite surface of the reading unit is disposed immediately before the image reading unit of the document, and the document is placed on the platen glass. By pressing toward the opposite surface, it is possible to prevent the document from fluttering and to prevent the image reading quality from deteriorating. Since the image surface of the document is guided without sliding on the platen glass, the platen glass is not soiled. In addition to the above configuration, the reading unit is provided with a recess opened on the document conveying surface between the reading unit and the document conveying roller immediately before the reading unit, and the base of the elastic film is fixed through the recess. The foreign matter released from the original can be stored in the recess provided upstream, and the foreign matter can be prevented from moving to the platen glass. In addition, by attaching the base of the elastic film to the recess, the film can be fixed well, and the elasticity of the tip of the film can be effectively exhibited. Further, since the leading end of the elastic film is provided so as to protrude just to the upstream end of the white plate for shading provided on the opposed surface of the reading unit, the leading end of the elastic film is capable of By pressing the platen glass against the surface immediately before the reading position, the trailing edge of the document does not flutter, and the image quality of the read image is not disturbed.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a configuration of an apparatus according to the present invention.
FIG. 2 is an explanatory diagram of an arrangement state of an elastic film.
FIG. 3 is an explanatory diagram showing a configuration of an automatic document feeder to which the document feeder of the present invention can be applied.
[Explanation of symbols]
1 Document feeder, 2 Upper frame, 3 Intermediate frame,
5 Document transport path, 7 Document tray, 8 Eject tray,
10 Document transport section, 11 Pickup roller,
12 feed rollers, 15 transport rollers,
18 discharge roller device, 20 reading section, 21 platen glass,
22 white film, 23 recesses, 25 elastic film,
26 double-sided tape, 27 set screw, 30 reader,
32 platen glass, 33/35 carriage,
38 lenses, 39 CCD.

Claims (1)

In a document conveying device configured to pass a document that is separated and fed from a document tray one by one through a reading unit via a U-turn unit,
A recess provided between the reading unit and the document conveying roller immediately before the reading unit, and opening in the document conveying surface;
An inclined surface formed on the side wall on the downstream side in the document conveying direction of the recess;
An elastic film disposed along the inclined surface;
A white film for shading attached to the opposite surface of the reading unit,
A base portion which is one end portion of the elastic film is fixed to the bottom surface of the recess, and the other end portion of the elastic film is attached so as to protrude toward an upstream end portion of the shading white film. An original conveying apparatus characterized by comprising:

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