Image scanner with image scanning device positioning

An image scanner in which in scanning an image of a document placed on a scanner body, an image scanning device moves and scans the image of the document. In scanning an image of a document fed by a document feeder to the scanner body, the image scanning device moves to a predetermined scanning position and then scans the image of the document in the scanning position. When the image scanning device arrives at the scanning position, the image scanning device is pressed against a stopper that is positioned relative to the document feeder.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image scanner, and more specifically, it relates to a structure for properly positioning an image scanning device.

2. Description of the Related Art

Image scanners that have a scanner body and a document feeder for feeding documents to the scanner body are known. In some of them, the document feeder can open and close like a lid of the scanner body.

When an image of a document placed on a document bed glass is scanned, an image scanning device provided in the scanner body moves in the sub-scanning direction and scans the image of the document. To scan an image of a document placed on a document bed glass will hereinafter be referred to as “flatbed scanning.” When an image of a document being moved on the document bed glass by the document feeder is scanned, the image scanning device moves to a predetermined scanning position and then scans the image of the document in the scanning position. To scan an image of a document being moved on the document bed glass by the document feeder will hereinafter be referred to as “sheet-feed scanning.”

When the document feeder is attached to the scanner body, the position of the document feeder is adjusted in order to ensure a predetermined relation between the scanning position, the position of the document feeder, and the direction in which a document is moved.

Japanese Patent Laid-Open No. 10-224553 discusses an image scanner in which an image scanning device of a scanner body is pressed against a document-conveying roller of a document feeder in order to ensure the position of the image scanning device relative to a document.

Japanese Patent Laid-Open No. 10-142851 (corresponding to U.S. Pat. No. 6,027,109) discusses an image scanner including a document feeder that has a sheet feeding device, a sheet conveying device, and a sheet discharging device formed as a unit, the unit having a projection to be pressed against the upper surface of a platen glass of a scanner body. The unit is positioned relative to the scanner body in the vertical direction. Therefore, when the document feeder is attached to the scanner body, adjustment in the vertical direction is made easy.

However, in the image scanner of Japanese Patent Laid-Open No. 10-224553, when adjustment of the document feeder is performed, a document is actually moved by the document feeder and it is calculated from the scanned image how much adjustment is required. Therefore, the adjustment takes a lot of time. In addition, when a document is actually moved and scanned, the scanned image varies depending on the condition of the document and the condition of the conveyance, and therefore it is difficult to achieve accurate adjustment.

Moreover, it is difficult to accurately position the image scanning device relative to the document feeder even if the image scanning device is pressed against the document-conveying roller. Therefore, it is difficult to ensure the relation between the scanning position, the position of the document feeder, and the direction in which a document is moved.

In the image scanner of Japanese Patent Laid-Open No. 10-142851, when the document feeder is attached to the scanner body, adjustment in the vertical direction is not needed. However, a document moved by the document feeder can skew relative to the scanner body. Therefore, the document feeder needs to be adjusted relative to the scanner body so that the document does not skew.

SUMMARY OF THE INVENTION

The present invention is directed to an image scanner in which an image scanning device can be accurately positioned relative to a document feeder, and the document feeder can be easily attached to a scanner body.

In an aspect of the present invention, an image scanner includes a scanner body configured to scan an image of a document, the scanner body including an image scanning device; a document feeder configured to feed documents to the scanner body, the document feeder being attached to the scanner body in a manner such that the document feeder can open and close; and a stopper positionable relative to the document feeder so as to position the image scanning device. When an image of a document placed on the scanner body is scanned, the image scanning device moves and scans the image of the document. When an image of a document fed by the document feeder to the scanner body is scanned, the image scanning device moves to a predetermined scanning position and then scans the image of the document in the scanning position. When the image scanning device arrives at the scanning position, the image scanning device is pressed against the stopper. The stopper is positioned relative to the document feeder.

In another aspect of the present invention, an image scanner includes a scanner body configured to scan an image of a document, the scanner body including an image scanning device and a stopper, the stopper having a hole; and a document feeder configured to feed documents to the scanner body, the document feeder being attached to the scanner body in a manner such that the document feeder can open and close, the document feeder having a pin adapted to be fitted in the hole of the stopper. When an image of a document placed on the scanner body is scanned, the image scanning device moves and scans the image of the document. When an image of a document fed by the document feeder to the scanner body is scanned, the image scanning device moves to a predetermined scanning position and then scans the image of the document in the scanning position. When the image scanning device arrives at the scanning position, the image scanning device is pressed against the stopper.

DESCRIPTION OF THE EMBODIMENTS

FIG. 1shows the structure of an image scanner according to a first embodiment of the present invention.

InFIG. 1, reference numeral100denotes the image scanner. The image scanner100includes a scanner body101and a document feeder201feeding documents S to the scanner body101.

The scanner body101has a contact image sensor (hereinafter referred to as CIS)110, which corresponds to an image scanning device. The CIS110includes a gradient-index lens111as an imaging device, xenon lamps112as illuminating devices, and an image sensor board113as a sensor unit. The gradient-index lens111, the xenon lamps112, and the image sensor board113are contained in a case115. The image sensor board113has a plurality of photoelectric elements, which are arrayed in the direction perpendicular to the plane of the paper inFIG. 1(in the main scanning direction). The image data from the photoelectric elements are transmitted in the order in which they are arrayed.

The CIS110is contained in a box-shaped carriage116and can move vertically therein. The CIS110is pressed upward by a spring117. In flatbed scanning, the CIS110with a slider114thereon is located under a document bed glass103on which a document S is placed. In sheet-feed scanning, the CIS110with the slider114thereon is located under another document bed glass (a sheet-feed scanning glass)104over which a document S passes. The slider114is a known slider, for example, a slider having rollers.

As shown inFIG. 2, guided by a guide shaft102and driven by a timing belt108that is driven by a motor105, the CIS110can move in the direction perpendicular to the main scanning direction (the sub-scanning direction). In flatbed scanning, the CIS110moves in the sub-scanning direction and scans the image of the document.

InFIG. 2, reference numeral110adenotes holes formed at both ends of the CIS110in the main scanning direction. Reference numeral119denotes pins projecting from the box-shaped carriage116. Reference numeral118denotes springs disposed between the carriage116and the CIS110. The pins119of the carriage116are loosely fitted in the holes110aof the CIS110. The CIS110is pressed leftward inFIG. 2by the springs118. At a starting position shown by reference character A where the flatbed scanning is started, the springs118press the CIS110so that the inner walls of the holes110aof the CIS110come into contact with the pins119. The contact between the pins119and the inner walls of the holes110apositions the CIS110at the starting position.

The document feeder201will be described with reference toFIG. 1. The document feeder201has a paper tray203on which documents S are placed. The document feeder201has a feeding unit208, a register roller209, an upstream scanning roller210, and a downstream scanning roller211. The feeding unit208feeds the documents S placed on the paper tray203one at a time. The register roller209corrects any skew of the documents S. The upstream scanning roller210and the downstream scanning roller211make the documents S pass over the sheet-feed scanning glass104. The document feeder201has a paper discharging roller212, which discharges the scanned documents S onto a discharged-paper tray204.

Reference numeral107denotes a scanner frame. The guide shaft102, the document bed glass103, the sheet-feed scanning glass104, and a jump platform105are fixed to the scanner frame107.

Next, concerning the image scanner100configured as above, how it scans an image of a document will be described.

First, the flatbed scanning (in which an image of a document S placed on the document bed glass103is scanned) will be described. After a document S is placed on the document bed glass103, the CIS110is moved in the sub-scanning direction together with the carriage116along the guide shaft102by the motor105via the timing belt108. While the CIS110is moved, the xenon lamps112illuminate the document on the document bed glass103, and light reflected by the document passes through the gradient-index lens111to form an image with 1× magnification on the image sensor board113. In this way, the image data of the document is scanned.

Next, the sheet-feed scanning (in which an image of a document S moved by the document feeder201is scanned) will be described. The scanner body101moves the CIS110to a predetermined scanning position, i.e., a sheet-feed scanning position B under the sheet-feed scanning glass104. Next, the feeding unit208of the document feeder201feeds the documents S placed on the paper tray203one at a time. Any skew of the document S fed by the feeding unit208is corrected by the register roller209. Next, the document S is passed over the sheet-feed scanning glass104by the upstream scanning roller210.

At this time, the CIS110is located under the sheet-feed scanning glass104. While the document S is passed over the sheet-feed scanning glass104, the xenon lamps112of the CIS110illuminate the document S. Light reflected by the document passes through the gradient-index lens111to form an image on the image sensor board113. In this way, the image data of the document is scanned.

The scanned document S is guided by the jump platform105back to the document feeder201and is discharged by the downstream scanning roller211and the paper discharging roller212onto the discharged-paper tray204.

As shown inFIG. 3, the document feeder201is attached to the scanner body101with hinges202so that it can open and close (contact and separate from the scanner body101). In the flatbed scanning, after a document S is placed on the document bed glass103, the document feeder201is closed to press the document S against the document bed glass103.

InFIGS. 1 and 2, reference numeral106denotes a stopper. When the CIS110arrives at the sheet-feed scanning position shown by reference character B inFIG. 2in order to perform the sheet-feed scanning, projections115aof the case115of the CIS110are pressed against the stopper106. Pressing the CIS110against the stopper106properly positions the CIS110. That is to say, the CIS110is positioned so that the direction in which photoelectric elements (not shown) are arrayed is perpendicular to the direction in which documents are moved by the rollers210and211of the document feeder201. Therefore, the image can be scanned accurately.

The CIS110pressed against the stopper106moves relative to the carriage116in the opposite direction to the motion of the carriage116, against the springs118. Therefore, the pins119come out of contact with the inner walls of the holes110a. That is to say, when the CIS110is pressed against the stopper106, the carriage116is not involved in the positioning of the CIS110.

The stopper106has holes106ain the top at both ends in the main canning direction (seeFIG. 2). As shown inFIGS. 4A and 4B, the document feeder201has positioning pins205to be fitted into the holes106a.

How to attach the document feeder201and the stopper106to (the scanner frame107of) the scanner body101will now be described.

First, the stopper106is loosely attached to the scanner body101. Next, the document feeder201is attached to the scanner body101with hinges202in a manner such that it can be opened and closed.

Next, the document feeder201is rotated downward to be closed. As shown inFIG. 4A, closing the document feeder201fits the positioning pins205of the document feeder201into the holes106aof the stopper106. The stopper106is properly positioned by the document feeder201, that is to say, by fitting the positioning pins205into the holes106a.

Next, with the positioning pins205fitted in the holes106aof the stopper106, the stopper106is fixed to the scanner frame107with screws120(seeFIG. 2).

As described above, the document feeder201properly positions the stopper106, and the stopper106properly positions the CIS110. Therefore, the CIS110can be properly positioned through the intermediation of the stopper106, and the CIS110is accurately positioned relative to the document feeder201.

In the present embodiment, first, the document feeder201is attached to the scanner body101, and then, the stopper106is properly positioned using the document feeder201. Therefore, the document feeder201need not be adjusted relative to the scanner body101. Incidentally, if the stopper106is displaced due to deformation with age, the position of the stopper106can be easily corrected in the above-described manner. Since the document feeder201need not be adjusted relative to the scanner body101, less man-hours are required during manufacture.

The operation after the stopper106is fixed with the screws120will be described. The positioning pins205are held by stays206. The stays206are moved upward and then fixed so that the positioning pins205are separated from the scanner body101when the document feeder201is closed (seeFIG. 4B). That is to say, after the stopper106is fixed with the screws120, the positioning pins205are fixed in positions where the pins do not project from the document feeder201toward the scanner body101. Therefore, in normal operation, the document S is prevented from being caught between the positioning pins205and the scanner body101and damaged.

Alternatively, the positioning pins205may be detachable from the document feeder201. In this case, after the fixation of the stopper106is completed, the positioning pins205are detached from the document feeder201.

The positioning pins205of the document feeder201and the holes106aof the stopper106constitute a positioning device for properly positioning the CIS110. This positioning device properly positions the CIS110relative to the document feeder201in the direction in which the document is moved. Therefore, the document feeder201need not be adjusted relative to the scanner body101. In addition, highly accurate positioning can be achieved. Therefore, the difference in position and angle between a document S and a scanned image can be minimized at low cost and with high reliability.

In the above embodiment, the stopper106is properly positioned using the positioning pins205. Alternatively, as in the modification shown inFIG. 8, the document feeder201may have a stopper against which the case115of the CIS110is pressed. InFIG. 8, the projections115aof the case115of the CIS110are pressed against a stopper106′. Pressing the CIS110against the stopper106′ properly positions the CIS110. The stopper106′ is integral with the frame F of the document feeder201. The stopper106′ is a rib projecting from the document feeder201toward the scanner body101. It goes without saying that the stopper106′ is perpendicular to the direction in which a document is moved by the conveyance system (including the rollers210and211) of the document feeder201.

FIG. 5shows the structure of an image scanner according to the present embodiment. Incidentally, inFIG. 5, the same reference numerals will be used to designate the same or corresponding components as those inFIG. 1.

InFIG. 5, reference numeral151denotes xenon lamps as illuminating devices. Reference numerals152to156denote reflecting mirrors. Reference numeral157denotes an imaging lens as an imaging device. Reference numeral158denotes a CCD (charge coupled device) receiving the light reflected by the document S. The present embodiment has a so-called “one-box-type” image scanning device in which the xenon lamps151, the reflecting mirrors152to156, the imaging lens157, and the CCD158are contained in a case150.

The one-box-type image scanning device106is positioned relative to the document bed glass103, the sheet-feed scanning glass104, and the stopper106in the same manner as in the first embodiment. The stopper106is also fixed in the same manner as in the first embodiment. The one-box-type image scanning device is properly positioned by being pressed against the stopper106. The one-box-type image scanning device106scans a document placed on the document bed glass103and a document being moved on the sheet-feed scanning glass104by the document feeder201.

The one-box-type image scanning device can be used in the modification shown inFIG. 8.

In the above-described image scanners, the position of the image scanning device in flatbed scanning is different from that in sheet-feed scanning. However, the present invention is not limited to this and can also be applied to an image scanner in which both a stationary document and a moving document are scanned through a common document bed glass131. Such an image scanner will be described as a third embodiment of the present invention.

FIG. 6shows the structure of an image scanner according to the present embodiment. Incidentally, inFIG. 6, the same reference numerals will be used to designate the same or corresponding components as those inFIG. 1.

InFIG. 6, reference numeral132denotes a stopper. Reference numeral221denotes a conveyer belt moving a document. When a document being moved by the conveyer belt221is scanned, the CIS110is pressed against the stopper132, thereby being positioned in a sheet-feed scanning position at an end of the document bed glass131.

In the flatbed scanning, that is to say, when an image of a document S placed on the document bed glass131is scanned, the CIS110moves together with the carriage116from the position shown inFIG. 6(starting position) in the sub-scanning direction.

In either case of a stationary document or a document being moved by the conveyer belt221, the present embodiment can scan the image through the document bed glass131.

In the flatbed scanning, if the stopper132is in the position shown inFIG. 6, the CIS110returning to the starting position may collide with the stopper132due to inertia and be damaged.

Therefore, the present embodiment has a retracting device. The retracting device retracts the stopper132so that the CIS110returning to the starting position does not collide with the stopper132.

The CIS110is fixed to a holder911with screws910. The holder911is supported by a slider901in a manner such that it can move vertically. In the flatbed scanning, the holder911moves downward. Together with the holder911, the stopper132also moves downward and is located in the position shown by a dotted line inFIG. 6. When the stopper132is located in this position, the projections115aof the CIS110do not come into contact with the stopper132.

The stopper132and the holder911are moved vertically by an eccentric cam903and a spring902. The holder911is in contact with the eccentric cam903. The spring902urges the stopper132downward. That is to say, the spring902urges the holder911against the eccentric cam903. The stopper132moves upward and downward in accordance with the rotation of the eccentric cam903.

As described above, in the present embodiment, the eccentric cam903and the spring902constitute the retracting device. Alternatively, the retracting device may be a solenoid.

In the present embodiment, the stopper132can be retracted from the position where the stopper132is located to properly position the image scanning device. Therefore, both a stationary document and a document being moved can be scanned through the same document bed glass.

Not only in the first and second embodiments but also in the present embodiment, after the stopper is fixed with the screws, the positioning pins of the document feeder201are fixed in positions where the pins do not project from the document feeder210toward the scanner body101.

It goes without saying that the above-described image scanners can be used not only by themselves but also incorporated in an image forming apparatus.

FIG. 7is a sectional view of an image forming apparatus that incorporates an image scanner according to any one of the first to third embodiments.

An image forming apparatus body2has sheet containers53and54, which contain different size sheets S (S1and S2). The image forming apparatus body2has sheet feeders56aand56bfor feeding sheets S2and S1contained in the sheet containers54and53, respectively.

A sheet fed by the sheet feeder56aor56bfrom the sheet container54or53is moved through a sheet feeding path57and a sheet conveying path60to a photoreceptor62. A register-roller pair60ais disposed in front of the photoreceptor62. The leading edge of the sheet is pressed against the register-roller pair60ain order to correct any skew of the sheet, and the sheet is stopped on the sheet conveying path60. When the image formation starts in the photoreceptor62, the sheet is fed to the photoreceptor62by the register roller pair60a.

According to the image data received from an image scanner100, a laser scanner61scans the photoreceptor62with laser light in the main scanning direction so as to form an electrostatic latent image on the surface of the photoreceptor62. Next, the electrostatic latent image becomes a toner image, that is to say, it is made visible using toner supplied from a developer D. The toner image is transferred by a transferor T to the sheet fed from one of the sheet containers53and54. The sheet with the toner image transferred thereto is sent to a fixer64with a conveyer belt63. The fixer64heats and presses the toner image on the sheet to fix the toner image to the sheet. The sheet with the toner image fixed thereto goes through a sorting flap66and a discharging roller pair65and is then discharged onto a discharged-sheet tray67.

In any one of the above-described embodiments, an image scanner has a positioning device for properly positioning an image scanning device, and the image scanning device is properly positioned using the positioning device relative to a document feeder in the direction in which a document is moved. Therefore, the document feeder need not be adjusted relative to a scanner body. In addition, highly accurate positioning of the image scanning device relative to the document feeder can be achieved.

This application claims the benefit of Japanese Application No. 2004-256058 filed Sep. 2, 2004, which is hereby incorporated by reference herein in its entirety.