Document reading device

A document reading device includes a movable member and a flexible document holder. The document holder is fixed at a first end to a free end of the movable member. The document holder is also fixed at a second end to the vicinity of a right-side end of a bottom surface of the document reading device. A portion of the document holder positioned immediately below a pivot axis of the movable member is not fixed to the bottom surface. When the movable member is pivoted to expose a portion of a document transport path, the document holder, except for the first and second ends as fixed to the bottom surface, hangs down without being folded.

CROSS REFERENCE

This Nonprovisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No. 2004-328039 filed in Japan on Nov. 11, 2004, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

The invention relates to document reading devices in which an original document stacked on a document tray is transported on a document transport path to an output tray through a document reading area.

Document reading devices commonly used in image forming apparatuses automatically feed a plurality of original document sheets whose images are to be read consecutively, from a document tray to a document reading area. In such document reading devices, an original document to be fed to the document reading area is transported on a document transport path that is formed so as to lead from the document tray to a document platen.

Some of such document reading devices are provided with a document transport path that has an approximately C-shaped curve. The curve allows an original document to be fed to the document platen in an approximately horizontal position. Also, the curve contributes to downsizing of a document transport device. In the case, the document transport path has an upper portion, a curved portion, and a lower portion. Thus, it is impossible to remove an original document jammed in the lower portion even when a top cover of the document transport device is opened.

To deal with the foregoing problem, JP H11-5659 A discloses that a document holder, which holds an original document placed on the document platen so that the document will not move, is pivoted around a pivot axis that is oriented parallel to a document transport direction, to expose a portion of a document transport path positioned immediately above the document holder.

However, the prior art document holder needs to be pivoted at a wide angle for proper removal of an original document jammed in the document transport path. A small pivot angle of the document holder makes it hard to reach an original document jammed at a rear side of the document reading device, thereby preventing proper removal of the jammed document.

In view of the foregoing problem, document reading devices have been proposed in which a portion of a bottom surface thereof positioned immediately below a lower portion of the document transport path serves as a movable member that is pivotable around a pivot axis oriented in a direction perpendicular to a document transport direction. The movable member is pivoted to expose the whole length, in the direction perpendicular to the document transport direction, of the lower portion of the document transport path.

On the bottom surface of the document reading device, however, a document holder for pressing an original document against the document platen is provided so as to extend over the whole length and breadth of the document platen. The document holder is a white, flexible sheet that is positioned outwardly with respect to the movable member.

If the document holder is entirely fixed to the bottom surface, a portion of the document holder positioned immediately below the pivot axis of the movable member is folded when the movable member is pivoted. Repeated pivot movements of the movable member cause the portion to have such a fold as to prevent the portion from pressing an original document flat against the document platen. Thus, there is a space left between the document holder and the document platen or between the holder and the original document. The space allows a leak of light irradiated on the document for scanning an image thereof. The leak results in undesirable image noise on image data read from the document. Also, a portion of the document is prevented from being pressed flat against the document platen. Accordingly, image data cannot be precisely read from the document.

A feature of the invention is to provide a document reading device capable of reading an image of an original document precisely. The document reading device has a movable member that is pivoted to expose a portion of a document transport path and a document holder that is positioned outwardly with respect to the movable member. The document holder is configured so as not to have a fold even after repeated pivot movements of the movable member. The configuration prevents undesirable image noise from appearing on image data read from an original document. Also, the configuration allows an original document to be pressed flat against the document platen.

SUMMARY OF THE INVENTION

A document reading device of the invention includes a movable member and a document holder. The movable member is supported pivotably around a pivot axis that is oriented perpendicular to a document transport direction on a document transport path. The movable member is pivotable from a position to cover a portion of the document transport path to a position to expose the portion toward a document platen. The document holder includes a flexible sheet and is positioned so as to extend over the whole length and breadth of the document platen. The document holder is fixed at portions other than a portion positioned immediately below the pivot axis, to a bottom surface of the document reading device.

DETAILED DESCRIPTION OF THE INVENTION

With reference to the accompanying drawings, the document reading device according to preferred embodiments of the invention will be described in detail below.

FIG. 1is a diagram illustrating a schematic configuration of an image forming apparatus100provided with a document reading device1according to a first embodiment of the invention. The image forming apparatus100includes an image reading section110, an image forming section210, and a sheet feeding section250. The image forming apparatus is also provided with a finishing device260and a multiple-tiered sheet feeding unit270.

The image forming section210has a photoreceptor drum222, a charging device223, a laser writing unit227, a developing device224, a transferring device225, a separating device229, and a cleaning device226. The charging device223charges a circumferential surface of the photoreceptor drum222so that the circumferential surface has a predetermined electrical potential. The laser writing unit227irradiates the circumferential surface of the photoreceptor drum222with laser light modulated according to image data, thereby forming an electrostatic latent image on the circumferential surface. The developing device224develops the latent image into a toner image by applying toner to the electrostatic latent image. The transferring device225transfers the toner image formed on the circumferential surface of the photoreceptor drum222onto a sheet. The separating device229separates a sheet from the circumferential surface of the photoreceptor drum222. The cleaning device226removes and collects residual toner from the circumferential surface of the photoreceptor drum222.

The document reading device1is movably provided above the image reading section110. The document reading device1is moved to expose respective upper surfaces of a first document platen12and a second document platen16. The image reading section110reads image data from an original document and transmits the image data to the image forming section210. The image data undergoes a predetermined image processing in an image processing section provided in the image forming section210. Then, the image data is temporarily stored in a memory of the image forming section210. Upon receipt of an output command, the image data is read out from the memory and transferred to the laser writing unit227.

It is to be noted that an optical writing head unit using an array of light-emitting elements such as LED or EL is substitutable for the laser writing unit227.

The sheet feeding section250is located below the image forming section210. The sheet feeding section250includes a sheet feeding tray251, a manual sheet feeding tray254, a duplex-printing unit255, and the multiple-tiered sheet feeding unit270. The unit270has sheet feeding trays252and253. In the sheet feeding section250, a sheet transport path is provided for transporting a sheet stored in any of the trays251to254via between the photoreceptor drum222and the transferring device225.

The duplex-printing unit255is used for printing on both sides of a sheet. The duplex-printing unit255is connected to a switchback path221. The switchback path221is provided for reversing leading and trailing edges of a sheet. The duplex-printing unit255is interchangeable with a normal sheet feeding tray or a large-capacity sheet feeding unit capable of storing several thousand sheets.

Provided at an output side of the image forming section210are a fusing unit217, the switchback path221, a finishing device260, and sheet output rollers219. The fusing unit217heats and presses a sheet that bears a transferred toner image, so that the toner image is fixed to the sheet. The switchback path221reverses leading and trailing edges of a sheet so that an image is formed on a reverse side of the sheet. The finishing device260, which has an elevating tray261, performs a finishing process such as stapling, to a sheet with an image formed thereon. After a toner image is fixed thereto in the fusing unit217, a sheet is led to the switchback path221, as necessary. Then, the sheet is guided, by the sheet output rollers219, into the finishing device260where the sheet undergoes predetermined finishing processes. Finally, the sheet is output onto the elevating tray261.

The image reading section110has a charge coupled device (CCD) scanning unit11, a light source unit13, and a mirror unit14. The CCD scanning unit11is fixed at a predetermined position. An original document is placed and held flat on the first document platen12. The light source unit13and the mirror unit14are used to produce an image of the original document on the CCD scanning unit11. An image reading process is thus performed. The CCD scanning unit11has an imaging lens and a CCD image sensor.

The light source unit13has a light source, a reflector, a slit, and a mirror. The light source irradiates illuminating light. The reflector focuses the illuminating light on a predetermined image reading area on the first document platen12. The slit allows only reflected light from an original document to pass therethrough. The mirror deflects the reflected light that passes through the slit, at an angle of 90 degrees. The mirror unit14has a pair of mirrors for deflecting the reflected light at an angle of 180 degrees.

In stationary reading mode, the light source unit13and the mirror unit14are reciprocated under the first document platen12along a slow scanning direction at velocities V and V/2, respectively. Thus, reflection of light irradiated over the whole length and breadth of an image-bearing side of an original document is collected in the CCD scanning unit11, with light path length maintained constant.

The configuration of the image reading section110includes, but is not limited to, the foregoing one. In an alternative configuration, the image reading section110has, as a substitute for the CCD scanning unit11, an optical unit provided with a CCD image sensor, an imaging lens, and a light source. In the stationary reading mode, the optical unit is reciprocated under the first document platen12along the slow scanning direction at velocity V.

The image reading section110has the second document platen16positioned at a predetermined distance in the slow scanning direction from the first document platen12. In transport reading mode in which the document reading device1is used, the light source unit13is held still so as to face a first image reading area P1across the second document platen16.

FIG. 2is a cross-sectional view illustrating a configuration of the document reading device1. The document reading device1has a document tray2and a document output tray3. An original document is stacked on the document tray2. After an image thereof is read, an original document is output onto the document output tray3. A document transport path H1is formed approximately in the shape of the letter C, so as to lead from the document tray2, through the first image reading area P1and a second image reading area P2, to the document output tray3. Arranged along the document transport path H1are a pick-up roller4, a feeding roller5A, a separating roller5B, and rollers R1to R6.

The rollers R1, R2, R4, and R5are transport rollers for transporting an original document on the document transport path H1at a predetermined speed. The rollers R3are registration rollers that are driven in synchronization with an image reading process performed in either of the image reading areas P1and P2. An original document fed from the document tray2is held, for skew correction, by the leading end thereof by the registration rollers R3that are in undriven state. Then, the registration rollers3are driven to transport the document to the image reading areas P1and P2at a predetermined timing. The roller R6is an output roller for outputting an original document whose image is read, to the document output tray3.

On the document transport path H1, a platen10is provided in the first image reading area P1with a predetermined distance from the second document platen16. The CCD scanning unit11reads an image of a first side of an original document while the document is being transported through the first image reading area P1that is located between the second document platen16and the platen10.

A glass platen21is provided at an upper side of the second image reading area P2. The second image reading area P2corresponds to the image reading area of the invention. The area P2is located downstream of the first image reading area P1in a document transport direction. Inside the document reading device1, a CCD8, mirrors22to25, and a lens26are arranged in a space surrounded by the document transport path H1. Light reflected from the second image reading area P2is brought to the CCD8through the glass platen21, the lens26, and the mirrors22to25. The CCD8reads an image of a second side of an original document while the document is being transported through the second image reading area P2.

Described below is an image reading process performed in simplex image reading mode in which an image of a single side of an original document is read. The pick-up roller4is rotated to pick up a top sheet of an original document stacked on the document tray2. The feeding roller5A is rotated to feed the sheet into the document transport path H1. The separating roller5B is rotated in the same direction as a direction in which the feeding roller5A is rotated. If the top sheet is picked up together with lower sheets, the lower sheets are separated from the top sheet and returned to the document tray2by the separating roller5B. Thus, only the top sheet is fed into the document transport path H1.

The sheet is transported on the path H1by the transport rollers R1and R2being rotated. The sheet is transported to the first image reading area P1at a predetermined timing by the registration rollers R3being rotated. While passing through the area P1, an image of a first side of the sheet is read by the CCD scanning unit11. After the image is read, the sheet is output to the document output tray3by the transport rollers R4and R5and the output roller R6being respectively rotated.

Next described below is an image reading process performed in duplex image reading mode in which images of both sides of an original document is read. After an image of a first side thereof is read in the first image reading area P1, an original document sheet is transported to the second image reading area2by the transport rollers R4and R5. While the sheet is being transported through the second image reading area P2, the CCD8reads an image of a second side of the sheet. Then, the sheet is output onto the document output tray3by the output roller R6being rotated.

A face panel20is provided so as to cover the outside of the document transport path H1. The face panel20includes a cover9that covers upper and left-side portions of the document transport path H1. The cover9is hinged at a lower left-side end. The cover9is integrated with a transport guide31. The transport guide31, which is approximately L-shaped, is located along outer sides of the upper and left-side portions of the document transport path H1.

The face panel20has a portion that serves as a bottom surface of the document reading device1, which is hereinafter referred to merely as the bottom surface. A first movable member6serves as a portion of the bottom surface that faces a lower portion of the document transport path H1. The first movable member6is supported pivotably around a pivot axis6A, so as to open downwards, i.e., toward the first document platen12. The pivot axis6A is oriented perpendicular to the document transport direction. Inside the document reading device1, a second movable member7is located inwardly with respect to the first movable member6. The second movable member7is supported pivotably around a pivot axis7A, so as to open downwards. The pivot axis7A is oriented perpendicular to the document transport direction.

Provided on the bottom surface is a document holder15that extends at least over the whole length and breadth of the first document platen12. The document holder15is a flexible sheet so elastic as to be easily deformed by an external force. The document holder15includes a white sheet and a cushioned mat. The white sheet comes in contact with an original document to be placed on the first original platen12. The cushioned mat includes a foam material such as urethane foam. The document holder15presses the original document as placed, flat against the first original platen12from above.

FIG. 3is a cross-sectional view illustrating respective open states of the first movable member6and the second movable member7provided in the document reading device1according to the first embodiment of the invention. A free end6B is moved toward the first document platen12(not shown), so that the first movable member6is pivoted around the pivot axis6A that is provided at a pivotal end6C. Simultaneously, a free end7B is moved toward the first document platen12, so that the second movable member7is pivoted around the pivot axis7A that is provided at a pivotal end7C. Thus, a portion of the document transport path H1leading from the image reading area P1through the image reading position P2to the vicinity of the output roller R6, which is hereinafter referred to merely as the portion, is exposed to the outside at the bottom of the document reading device1. The exposure facilitates removal of a jammed original document from the document transport path H1.

In the first embodiment, the document holder15is fixed at a first end15A to a free end6B of the first movable member6. The document holder15is also fixed at a second end15B to the vicinity of a right-side end of the bottom surface. A portion of the document holder15positioned immediately below the pivot axis6A is not fixed to the bottom surface.

When the first movable member6is pivoted to expose the portion of the document transport path H1, the document holder15hangs down, except for the ends15A and15B as fixed to the bottom surface. Thus, the document holder15is not caused to have a fold at a portion thereof, particularly at the portion immediately below the pivot axis6A, even after repeated pivot movements of the first movable member6.

The foregoing configuration prevents a space allowing a leak of light irradiated on an original document placed on the first original platen12from being left between the document holder15and the platen12or between the holder15and the original document. Thus, the configuration prevents generation of image noise on image data. The foregoing configuration also allows an original document to be pressed flat against the platen12, thereby allowing precise reading of image data.

FIG. 4is a cross-sectional view illustrating respective open states of the first movable member6and the second movable member7provided in the document reading device1according to a second embodiment of the invention. In the second embodiment, the document holder15is fixed at the first end15A to the free end6B. The document holder15is also fixed at an intermediate portion15C to a portion of the bottom surface other than the free end6B and the pivotal end6C. The document holder15is further fixed at the second end15B to the vicinity of the right-side end of the bottom surface. A portion of the document holder15positioned immediately below the pivot axis6A is not fixed to the bottom surface.

When the first movable member6is pivoted to expose the portion of the document transport path H1, a comparatively small portion of the document holder15from the intermediate portion15C to the second end15B hangs down. Thus, the document holder15is not caused to have a fold at a portion thereof, particularly at the portion immediately below the pivot axis6A, even after repeated pivot movements of the first movable member6. Further, the foregoing configuration allows a comparatively small space to be formed between the bottom surface and the document holder15when the movable members6and7are pivoted. The space is sufficiently small to prevent foreign objects from getting thereinto.

FIG. 5is a cross-sectional view illustrating respective open states of the first movable member6and the second movable member7provided in the document reading device1according to a third embodiment of the invention. In the third embodiment, the document holder15is fixed at the first end15A to the free end6B. The document holder15is also fixed at the intermediate portion15C to a portion of the bottom surface other than the free end6B and the pivotal end6C. The second end15B is attached to the vicinity of the right-side end of the bottom surface, so as to be movable along a direction parallel to the bottom surface. A portion of the document holder15positioned immediately below the pivot axis6A is not fixed to the bottom surface.

The second end15B is attached to the vicinity of the right-side end of the bottom surface in a manner as described below, for example. A pin with a flange attached to a lower edge is projected downward from the bottom surface. A lengthwise slit is formed in an upper surface of the document holder15at the second end15B. The flange is fitted into the slit.

When the first movable member6is pivoted to expose the portion of the document transport path H1, a portion of the document holder15from the intermediate portion15C to the second end15B is moved in the direction parallel to the bottom surface without hanging down. Thus, the document holder15is not caused to have a fold at a portion thereof, particularly at the portion immediately below the pivot axis6A, even after repeated pivot movements of the first movable member6. Further, the foregoing configuration allows little space to be formed between the bottom surface and the document holder15when the movable members6and7are pivoted. Accordingly, foreign objects are prevented from getting between the bottom surface and the document holder15.

It is to be noted that the above-described configurations are illustrative examples. There are other possible configurations to meet the condition that at least a portion of the document holder15immediately below the pivot axis6A is not fixed to the bottom surface.