JP4330827B2 - Document reader - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an original reading apparatus used for an electrophotographic copying machine, a facsimile, a printer, and the like.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, this type of document reading apparatus has a document conveying unit called an ADF (Automatic Document Feeder) that feeds documents one by one from a sheet feeding unit and automatically supplies them to a document reading position. A document reading unit that reads an image of the document with a scanner.
[0003]
The document reading unit is provided with scanning means for reading the documents sequentially conveyed from the document conveying unit. As this scanning means, for example, light is applied to a document passing over a platen, and the reflected light is collected by a condenser lens and detected by a CCD line sensor, or light is applied to a document passing over a platen. There are those that are irradiated and directly detected by a contact sensor without condensing the reflected light.
[0004]
By the way, when scanning a conveyed document by such a scanning unit, there is a problem that a read image is distorted when the document flutters at an actual reading position. For this reason, for example, as disclosed in Japanese Patent Application Laid-Open No. 10-139211, a technique for smoothly feeding a document into a gap (document reading position) between a platen and a document pressing member is known.
[0005]
That is, in this known technique, as shown in FIG. 5, a pair of upper and lower plate-like elastic pieces 62 and 63 are arranged in the conveyance path 61 on the upstream side of the platen 60, and the original 64 is made to be the plate-like elastic piece 62. , 63 so that the document 64 is fed onto the platen 60 in a fixed path without changing the posture.
[0006]
[Problems to be solved by the invention]
By the way, a general document reading apparatus is provided with a guide member for scooping up the front end of the read document and guiding it to the discharge tray side on the downstream side of the document reading position. The conveyance path is curved toward the paper discharge side.
[0007]
Therefore, in the above-described known technique, the document 64 can be fed onto the platen 60 so as to be sandwiched between the plate-like elastic pieces 62, 63, but the plate-like elastic pieces 62, 63 are located downstream of the document reading position. Therefore, there is no means for restricting the conveyance of the document 64 at the curved portion of the guide member 65, the leading end 64a of the document 64 that has passed the document reading position hits the curved portion of the guide member 65, or the document 64 is guided. There is a problem such as being transported toward the paper discharge side away from the curved portion of the member 65. In such a case, the reading speed of the original at the original reading position becomes unstable, and the read image is distorted. There was a risk.
[0008]
SUMMARY OF THE INVENTION An object of the present invention is to provide a document reading apparatus that can reliably prevent distortion of a read image by keeping a document reading speed at a document reading position constant.
[0009]
[Means for Solving the Problems]
In order to solve the above-described problem, a document reading apparatus according to a first aspect of the present invention includes a platen for reading a document, a first transport unit disposed on the upstream side of the platen, and a downstream side of the platen. In a document reading apparatus comprising: a second conveying unit disposed; and a guide member that scoops up a document from the platen and guides the document toward the second conveying unit, the document reading device is disposed downstream of the platen from the upper surface of the platen. And a flexible film member that presses the document over the guide surface of the guide member, and a restricting member that is disposed to face the guide surface across the film member, The film member has a positioning protrusion for abutting on the guide surface and maintaining a constant interval between the guide surface and the regulating member, and the film member within the constant interval held by the positioning protrusion. Characterized by regulating the vertical movement.
[0010]
The flexible film member is preferably made of a mylar film made of a polyester film having a thickness of about 0.1 mm, for example, and is preferably configured widely so as to press the entire document. The film member is long from the upstream side of the document reading position set on the platen to the guide surface of the guide member so that the document can be pressed from the upper surface of the platen to the guide surface of the guide member. The one end on the upstream side is fixed and the other end on the downstream side is free so that it can be extended and an appropriate pressing force can be applied.
[0011]
The above regulating member, that have a positioning protrusion for being positioned at a position at a predetermined distance from the guide surface of the upper surface or the guide member of the platen. By positioning the regulating member at a position spaced a predetermined distance from the upper surface of the platen or the guide surface of the guide member, the movement of the film member can be accurately regulated at an appropriate location. In order to accurately regulate the movement of the film member, the regulating member is a plate-like portion that covers the film member above the platen, and a regulating surface that extends in the document width direction formed on the end surface of the plate-like portion on the guide member side With. A positioning protrusion that abuts against the guide surface of the guide member or the upper surface of the platen protrudes from the restriction surface, and maintains the predetermined interval. Further, the restricting member includes an urging means for urging the restricting surface side of the plate-like portion toward the platen side in order to maintain a position at a predetermined interval.
[0012]
According to the present invention configured as described above, the flexible film member presses the document from the upper surface of the platen to the guide surface of the guide member, so that the document that has passed through the document reading position is scooped up by the guide member. Even if the film is conveyed so as to be bent, the film member appropriately presses the document, so that the document is smoothly conveyed along the guide surface of the guide member. Further, even if a stiff original such as a thick paper original tries to push up the film member at the curved portion of the guide member, the restricting member restricts the upward movement of the film member at a predetermined position. The cardboard document is conveyed while being pressed. Therefore, the reading speed of the original at the original reading position is always constant in both the thin paper original and the thick paper original, and the distortion of the read image is surely prevented. As described above, original documents can be read as designed even for thick paper originals without increasing the pressing force of the film member , and an original reading apparatus applicable to both thin paper originals and thick paper originals can be obtained.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a document reading apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is an internal configuration diagram of an embodiment of a document conveying device mounted on a document reading device, and FIG. 2 is an enlarged view of the vicinity of a document reading position in the document reading device. FIG. 3 is a partial perspective view showing an embodiment of the restricting means, and FIG. 4 is an explanatory view when the document is conveyed near the document reading position.
[0014]
As shown in FIG. 1, the document conveying device 1 according to this embodiment includes a sheet feeding unit that separates and feeds documents stacked on a sheet feeding tray 2 one by one, and a fed document as a platen 4. A document feeding section for feeding the scanned document to the document reading position 5 and feeding the scanned document from the document reading position 5, and a paper discharge section for discharging the document after reading the document.
[0015]
The paper feed unit includes a paper feed tray 2 for stacking documents, a pickup roller 6 that presses against the upper surface of the documents stacked on the paper feed tray 2 and feeds the uppermost document, and feeds by the pickup roller 6 A paper feed roller 7 and a separation roller 8 for separating and feeding the originals one by one are provided. The pickup roller 6 is swingably connected to the paper feed roller 7 by a connecting arm 9, and both can be rotated forward and backward via a one-way clutch (not shown) that can rotate only in one direction. . The separation roller 8 is elastically brought into contact with the paper feed roller 7 by a spring member 10 pushed up from below and can be driven by the paper feed roller 7.
[0016]
The paper feed tray 2 is provided in a state inclined downward toward the paper feed side, and a guide plate 11 that slides in the document width direction is disposed. The guide plate 11 defines the width-direction dimension of the document, and side guides 12 for restricting both sides of the document are provided upright on both sides. In this embodiment, the side guide 12 extends forward along both side end portions of the guide plate 11, and the tip reaches the vicinity of the paper feed port 13 on the downstream side of the pickup roller 6. Further, an upper surface regulation guide 14 for regulating the upper surface of the document is provided at the upper end of the side guide 12. The upper surface regulating guide 14 is formed so as to protrude in the horizontal direction from the upper end of the side guide 12, and continuously extends from a substantially central position of the side guide 12 to the vicinity of the document feeding position by the pickup roller 6. Yes.
[0017]
In the conveying section, a document fed on the downstream side of the paper feeding roller 7 is fed by a document reading position 5 (specifically, a document reading unit disposed below the platen) provided on the platen 4 of the document reading device. A conveyance path is provided for conveying the document to a position where the document is read when the document passes over the platen. The conveyance path includes a first conveyance path 20 that reverses the original while bending and conveys the original to the original reading position 5, and a second conveyance path 21 that conveys the original that has passed through the original reading position 5. The first conveying path 20 is formed in a substantially U shape by an outer guide plate 22 and an inner guide plate 23 having a bent shape, and conveys a document into the conveying path in the vicinity of the upstream side of the platen 4. A pair of conveying rollers 24 and 25 are provided. Further, on the upstream side of the conveying rollers 24 and 25, a first idler roller 26 is disposed immediately downstream of the paper feed roller 7, and a second idler roller 27 is disposed at an intermediate bent portion. Since these first and second rollers 26 and 27 have a large degree of bending of the first conveyance path 20, contact friction between the original and the bent portion of the inner guide plate 23 generated when the original is conveyed by the conveyance rollers 24 and 25. These are all arranged so as to slightly protrude from the inner guide plate 23 side into the first conveyance path 20 at the bent portion. Further, a guide piece 28 for guiding the document onto the platen 4 is disposed in the first transport path 20 immediately downstream of the transport rollers 24 and 25.
[0018]
On the other hand, as shown in FIGS. 1 and 2, the second transport path 21 is formed in a substantially linear shape by an upper guide plate 40 and a lower guide plate 41 that are inclined obliquely upward from the downstream end of the platen 4. At the downstream end thereof, a pair of paper discharge rollers 43 and 44 for conveying the document that has passed the document reading position 5 to the paper discharge tray 42 are disposed. Further, a scooping guide member 45 for scooping up the document read at the document reading position 5 of the platen 4 so as to be bent and guiding it to the second transport path 21 is disposed immediately downstream of the platen 4. The scooping guide member 45 is formed with a guide surface 46 that is inclined from the downstream end of the platen 4 toward the lower guide plate 41, and the document is guided along the guide surface 46.
[0019]
As described above, a curved conveyance path is formed between the conveyance rollers 24 and 25 and the discharge rollers 43 and 44 via the platen 4, and the curve defined by the platen 4 and the scooping guide member 45 described above. In the portion, a film member that presses the conveyed document toward the upper surface of the platen 4 and the scooping guide member 45 is disposed.
[0020]
As shown in FIGS. 1 to 3, this film member extends from the upstream side of the document reading position 5 of the platen 4 to the middle of the second transport path 21 along the guide surface 46 of the scooping guide member 45. A sheet 51 is used. The mylar sheet 51 is made of a polyester film having a thickness of about 0.1 mm, one end on the upstream side is fixed to a frame portion 53 of a regulating member 52 described later, and the other end on the downstream side is in a free state. The scooping guide member 45 extends to a part of the second transport path 21 along the inclined surface 46 and contacts the lower guide plate 41. The Mylar sheet 51 may be configured to press a part of the conveyed document in the width direction, but as shown in FIG. 3, it is desirable to configure the document so as to press the entire document. . That is, it is preferable that the width of the maximum document processed by the document conveying device is larger. As described above, the Mylar sheet 51 is disposed so as to moderately press the document over the guide surface 46 of the scooping guide member 45 and a part of the second transport path 21 from the upper surface of the platen 4. Of course, at the reading position 5, the document is also scooped along the guide surface 46 at the curved portion that moves from the platen 4 to the scooping guide member 45 in order to press the document appropriately at the downstream side of the document reading position 5. 2 is smoothly guided to the transport path 21. As a result, the leading edge of the document does not hit the guide surface 46 of the scooping guide member 45 or the document is not conveyed away from the guide surface 46 of the scooping guide member 45.
[0021]
On the other hand, the upward movement of the Mylar sheet 51 is restricted by a restriction member 52 as shown in FIGS. The restricting member 52 is formed on a substantially rectangular plate-like portion 54 that covers the mylar sheet 51 from above, a frame portion 53 that adheres and fixes the mylar sheet 51, and an end surface opposite to the frame portion 53. A regulation surface 58 extending in the document width direction, and positioning protrusions 55 projecting from both ends of the regulation surface 58 to the side of the guide member 45, and vertical wall pieces 56 rising from both the left and right sides of the plate-like portion 54 are document conveying devices. It is pivotally supported by the main body so that it can swing. Further, the regulating member 52 is spring-biased on the regulating surface 58 side to the platen 4 side by a spring member 57 arranged between the document conveying device. Further, since the spring bias as described above acts on the restricting member 52, the positioning protrusion 55 abuts a part of the guide surface 46 of the scooping guide member 45, and the restricting surface 58 is moved from the guide surface 46 to a predetermined amount. It can be positioned at a position separated by the interval S, and the Mylar sheet 51 is inserted into the interval S. Therefore, when the original is scooped up from the downstream side of the platen 4 to the curved portion of the scooping guide member 45, or while the original is being transported through the second transport path 21, a force that pushes up the mylar sheet 51 from the original is applied. Even so, since the restriction surface 58 prevents the mylar sheet 51 from being pushed up, the mylar sheet 51 does not rise. Then, since the original is conveyed while being pushed back by the Mylar sheet 51, the original can be conveyed along the guide surface 46 of the scooping guide member 45, and is smoothly guided to the second conveyance path 21.
[0022]
Next, the operation of the document reading apparatus 1 having the above configuration will be described. As shown in FIG. 1, an original is placed on the paper feed tray 2, the guide plate 11 is slid left and right, and both side portions of the original are regulated by the side guide 12. When the original on the paper feed tray 2 is detected by the empty sensor, the drive motor is driven to rotate forward, and the pickup roller 6 feeds the uppermost original while strongly pressing the upper surface of the original. The fed document is fed to the paper feed roller 7 through the paper feed port 13, but both sides may float when the central portion of the document is pressed by the pickup roller 6. However, since the upper surface regulation guide 14 that regulates the upper surface of the document extends to the document feeding position, the document is prevented from being lifted and does not come off the side guide 12. Therefore, the document is fed to the sheet feed port 13 with both side portions regulated, and is nipped by the sheet feed roller 7 and the separation roller 8. A single sheet is reliably separated by a paper feed roller 7 that rotates in the same direction as the pickup roller 6 and a separation roller 8 that elastically presses from below, and the separation roller 8 is driven to rotate to follow the first conveyance path 20. To be sent to.
[0023]
The document fed to the first conveyance path 20 is conveyed by the conveyance rollers 24 and 25 after the leading end is nipped by the conveyance rollers 24 and 25. Although the first conveyance path 20 is largely bent, since the first idler roller 26 is disposed in the bent portion immediately downstream of the separation roller 8, the friction resistance at the bent portion is reduced. It is transported smoothly. Further, since the second idler roller 27 is also disposed at another bent portion, the frictional resistance with the inner guide plate 23 at the bent portion is reduced, and the document is smoothly conveyed by the conveying rollers 24 and 25. Is called.
[0024]
The document moving on the first conveyance path 20 by the conveyance rollers 24 and 25 is guided to the document reading position 5 on the platen 4 by being guided by the guide piece 28 and the mylar sheet 51 located immediately downstream of the conveyance rollers 24 and 25. It is sent. The document subjected to the reading process is scooped up while being pressed against the guide surface 46 of the scooping guide member 45 by the pressing force of the mylar sheet 51, and is guided into the second transport path 21 as it is. 44 is conveyed onto the paper discharge tray 42.
[0025]
As a result, the original fed to the document reading position 5 and then transported to the scooping guide member 45 through the document reading position 5 is subjected to a mylar sheet during a series of transport operations passing through the document reading position 5. 51 is pressed by the elastic force on the free side 51, so that it does not flutter in the vertical direction on the platen 4, and the scooping operation by the scooping guide member 45 is performed smoothly. It becomes constant and no distortion occurs in the read image. In particular, at the curved portion from the downstream end of the platen 4 to the scooping guide member 45, the document 3 is conveyed while closely contacting along the guide surface 46 of the scooping guide member 45 as shown in FIG. 4.
[0026]
Further, in this embodiment, the upward movement of the mylar sheet 51 is restricted by the restriction member 52 positioned on the scooping guide member 45, and therefore, the downstream side of the platen 4 by a strong original such as a thick paper original. Even if a pushing force is applied from the document 3 to the mylar sheet 51 at the curved portion extending from the scooping guide member 45 to the scooping guide member 45, the restricting surface 58 of the restricting member 52 prevents the mylar sheet 51 from being lifted up and bent, and the document 3 In the state of being pressed by the sheet 51, the sheet is guided into the second conveyance path 21 along the scooping guide member 45. As a result, stable conveyance of the document 3 is ensured by the upper surface of the platen 4 and the curved portion of the scooping guide member 45. Accordingly, stable document reading of a thick paper document is executed without using a mylar sheet having a strong pressing force, and a moderate pressing force is sufficient for the mylar sheet, so that the document reading of a thin paper document is also stable. Note that the free end of the mylar sheet 51 has long entered the second transport path 21, so that the free end of the mylar member 51 does not jump out when the document transport device is opened or closed.
[Brief description of the drawings]
FIG. 1 is an internal configuration diagram of a document conveying device showing an embodiment of a document reading device according to the present invention.
FIG. 2 is an enlarged view of the vicinity of a document reading position of the document reading apparatus according to the present invention.
FIG. 3 is a partial perspective view showing an embodiment of a regulating member.
FIG. 4 is an explanatory diagram illustrating document conveyance in the vicinity of a document reading position.
FIG. 5 is a configuration diagram illustrating an example of a conventional document reading apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Document conveying apparatus 4 Platen 5 Document reading apparatus 20 1st conveyance path 21 2nd conveyance path 24 and 25 Conveyance rollers 43 and 44 Paper discharge roller 45 Scooping guide member 46 Guide surface 51 Mylar sheet 52 Restriction member 54 Plate-shaped part 55 Positioning Projection piece 57 Spring member 58 Restriction surface

Claims (4)

A platen for reading a document, a first transport unit disposed on the upstream side of the platen, a second transport unit disposed on the downstream side of the platen, and the second transport unit scooping up the document from the platen In a document reading apparatus provided with a guide member that guides toward
A flexible film member that presses the document over the guide surface of the guide member disposed on the downstream side of the platen from the upper surface of the platen;
A regulating member disposed opposite to the guide surface across the film member,
The restricting member has a positioning protrusion for abutting on the guide surface and maintaining a constant interval between the guide surface and the restricting member, and within the constant interval held by the positioning protrusion. An original reading apparatus characterized by restricting the vertical movement of the film member . 2. The document reading apparatus according to claim 1, wherein the regulating member has a regulating surface orthogonal to a document conveying direction at a tip portion held at a predetermined interval from the guide surface by the positioning protrusion.   The film member extends long from the upstream side of the document reading position set on the platen to the guide surface of the guide member, and one end portion on the upstream side is fixed, while the other end on the downstream side is free. The document reading device according to claim 1. The document reading apparatus according to claim 1, wherein the restriction member includes an urging unit for bringing the positioning protrusion into contact with the guide surface.

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