JP4476823B2 - Image reading apparatus and image forming apparatus - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus and an image forming apparatus, for example, an image reading apparatus that reads a document placed on contact glass such as a copying machine, a facsimile machine, and a scanner apparatus using a moving optical system, and the image reading apparatus. The present invention relates to an image forming apparatus.

  As image reading devices such as copiers, facsimile machines, and scanner devices are downsized, the components of the image reading device are required to be small and highly accurate, making it difficult to place parts with wasted space and room. ing.

  As a conventional image reading apparatus of this type, for example, an apparatus shown in FIG. 7 is known. In FIG. 7, below the contact glass 1 on which the document is placed, a light source 2 for illuminating the document and a reflecting member 3 having a reflecting surface at a portion indicated by a broken line are provided. Part of the reflected light is reflected by the reflecting member 3 and irradiated on the document together with the light from the light source 2.

  The light irradiated on the document by these lights is folded back by the reflecting mirror 4 and a reflecting mirror (not shown) and guided to an optical lens (not shown). An image formed on the optical lens is a CCD (not shown) or the like. The photoelectric conversion is performed by the image sensor.

  The light source 2, the reflecting member 3, and the reflecting mirror 4 are mounted on a carriage 5 so as to move in the sub-scanning direction of the document. The carriage 5 extends from one end to the other end of the contact glass 1. It is supposed to move in.

  A document scale 6 for aligning the end face of the document is provided at one end of the contact glass 1, and the document scale 6 is fixed to a document scale fixing bracket 8 by a fixing screw 7.

  A white reference plate 9 is provided on one end side of the contact glass 1, and this white reference plate 9 is on the back surface of the document scale 6 and on the upper surface of the contact glass 1 (substantially the same surface as the document placement surface). It is installed and used when performing shading correction.

  Specifically, it has uniform reflection characteristics due to factors such as sensitivity unevenness for each pixel of the image sensor, variation in transmitted light amount in the optical lens, illumination unevenness in the illumination / optical system, light amount distribution and deterioration in the main scanning direction, etc. The output from the light receiving element for each pixel when the reference plate is read is not necessarily a constant and uniform value.

  For this reason, shading correction for correcting these is performed. In this shading correction, the white reference plate 9 arranged on one end side of the contact glass 1 is read prior to actual reading of the original, and white level reference data is obtained as white data for shading correction of each pixel. Then, shading correction data is generated based on the acquired white reference data, correction operation is performed on the original image data read by the correction data, and the read data is normalized (for example, patent document). 1).

  In general, the contact glass 1 is chamfered (chamfered) as shown in FIG. (Shown as part 1a).

JP-A-9-149251

  However, in such a conventional image reading apparatus, when the white reference plate 9 is read through the chamfered portion 1a of the contact glass 1 and when the white reference plate 9 is passed through the contact glass 1 except for the chamfered portion 1a. Since the change in the amount of light at the time of reading is large, there is room for improvement in order to read a document image satisfactorily.

  Specifically, the reflected light from the reflecting member 3 irradiates the white reference plate 9 in the situation as shown in FIGS. FIG. 8 shows a state in which the reflected light from the reflecting member 3 is irradiated to the white reference plate 9 through the chamfered portion 1a on one end side of the contact glass 1, and the two-dot chain line is one of the light states. Part. FIG. 9 shows a state in which the reflected light from the reflecting member 3 is irradiated on the white reference plate 9 without passing through the chamfered portion 1a, and a two-dot chain line represents a part of the light state. .

  FIG. 10 is a diagram showing the distribution of the amount of light applied to the white reference plate through the contact glass 1. The solid line a passes through the chamfered portion 1a as shown in FIG. 8, and the broken line b is shown in FIG. As shown, the light quantity distribution when not passing through the chamfered portion 1a is shown.

  Based on this situation, the output of the image sensor when reading the white reference plate 9 is shown in FIG. In FIG. 11, the output from the image sensor corresponding to the position of the white reference plate 9 is slightly higher in the portion (the portion indicated by A) on the right side from the end of the white reference plate 9 than the other portions. It has become. This portion is an output of the image sensor when the light from the reflecting member 3 passes through the chamfered portion 1a, and is due to a change in the amount of light by the chamfered portion 1a.

In the shading correction, the white reference plate in the entire effective range indicated by the two-dot chain line in FIG. 8 is read and averaged, so the reading value of the white reference plate 9 needs to be flat. If an output change is caused by this, accurate shading correction cannot be performed.
In such a case, the output image has problems such as density unevenness, color difference from the original, and density difference from the original.

  As countermeasures for this problem, there is a method in which the arrangement position of the white reference plate 9 is moved away from the chamfered portion 1a of the contact glass 1 until the influence of the chamfer is eliminated, or the light source 2 is turned on after the reflecting member 3 passes the chamfered portion 1a. However, in any case, the image forming apparatus becomes larger or heavier, and as a result, the manufacturing cost of the image forming apparatus increases.

  Further, if the chamfered portion 1a of the contact glass 1 is eliminated, the above-described problems are improved. However, in this case, the yield of non-defective products of the contact glass 1 is deteriorated, and the manufacturing cost of the image reading apparatus is reduced. It will increase.

  In particular, an image reading apparatus that can read an A3 size document requires a contact glass 1 having an A3 size or larger, and is therefore very expensive. Furthermore, when an object or the like comes into contact with the contact glass 1 for any reason in the manufacturing process of the image forming apparatus, glass chipping occurs, leading to an increase in manufacturing cost.

  The present invention has been made to solve such a problem, and can read a document satisfactorily while preventing an increase in size and manufacturing cost and performing an optimal shading correction. It is an object of the present invention to provide an image reading apparatus and an image forming apparatus capable of performing the above.

The image reading apparatus of the present invention holds a light source that exposes a document placed on the contact glass, and a reflection mirror that folds reflected light from the light source and the document and guides it to an optical lens. A holding unit that can move in a predetermined scanning direction, an imaging unit that photoelectrically converts an image formed by the optical lens and reads an image of the document, and provided on one end side of the contact glass surface that contacts the document is, in the image reading apparatus provided with a white reference plate for performing shading correction of the imaging means, a chamfered portion is provided in at least one ridge line direction of the contact glass forming the scanning direction perpendicular of the retaining means, the chamfered portion Is formed of a concave in a substantially arc shape toward the inside of the contact glass.

  With this configuration, it is possible to prevent the light passing through the chamfered portion from spreading radially and increase the amount of light when reading the end portion side of the white reference plate, and perform good shading correction. As a result, it is possible to read a document satisfactorily while preventing an increase in the size and manufacturing cost of the image reading apparatus.

An image forming apparatus according to the present invention includes the above-described image reading apparatus and an image forming unit that forms an image on a recording medium.
With this configuration, it is possible to perform optimal shading correction while preventing an increase in size and manufacturing cost, and it is possible to read a document well and form a good image.

  As described above, according to the present invention, an image reading apparatus and an image that can read a document satisfactorily while performing an optimal shading correction while preventing an increase in size and an increase in manufacturing cost. A forming apparatus can be provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 4 are diagrams showing a first embodiment of an image reading apparatus and an image forming apparatus according to the present invention. The present invention can be applied to a scanner device, a facsimile device, and the like as an image reading device, and can be applied to a copying machine, a laser printer, a multifunction printer, an ink jet printer, a printing machine, and the like as an image forming device. In the present embodiment, a copying machine will be described as an example of the image forming apparatus.

  First, the configuration will be described. In FIG. 1, a copying machine 10 as an image forming apparatus includes an image reading device 11, a printer unit 12 having a laser beam scanning device, and an automatic document feeder 13.

  Here, the automatic document feeder 13 conveys the set originals one by one, sets the originals on the contact glass 14, and discharges the originals on the contact glass 14 after the completion of copying.

  As shown in FIG. 2, the document reading device 11 also includes a first carriage 61 equipped with an illumination lamp 15, a light source composed of a reflecting mirror 16 and a first mirror 17, and a second mirror 18 and a third mirror 19. The second carriage 62 is provided. In the present embodiment, the first carriage 61 and the second carriage 62 constitute holding means.

  The document reading device 11 includes a color filter 20 that filters a reflected light image sent from the second carriage 62, an optical lens 21 that forms a reflected light image that has passed through the color filter 20, The CCD sensor (imaging means) 22 that converts the reflected light image formed by the optical lens 21 into an analog image signal, the analog / digital converter, and the digital image signal converted by the analog / digital converter are subjected to image processing. A circuit board 23 on which an image processing circuit is mounted and a cooling fan 24 for cooling the illumination lamp 15 are provided.

  In the document reading apparatus 11, when reading a document, the first carriage 61 moves forward in the sub-scanning direction (predetermined direction) at a constant speed, and the second carriage 62 moves to the first carriage 61. The document on the contact glass 14 is optically scanned by following the first carriage 61 at a speed of 1/2 and moving in the sub-scanning direction, and the document on the contact glass 14 is illuminated with the illumination lamp 15 and the reflecting mirror. The reflected light image is imaged on the CCD sensor 22 by the lens 21 via the first mirror 17, the second mirror 18, the third mirror 19, and the color filter 20.

  The CCD sensor 22 photoelectrically converts the reflected light image of the imaged document to output an analog image signal, and the circuit board 23 converts the image into a digital image signal for image processing. .

Further, after the end of image reading, the first carriage 61 and the second carriage 62 are moved back to the home position HP position. As the CCD sensor 22, a color original can be read by using a three-line CCD provided with red (R), green (G), and blue (B) filters.
The printer unit 12 also includes a photosensitive drum 25 on which an electrostatic image is formed, a charging device 26 that uniformly charges the photosensitive drum 25, and laser beam scanning that forms an electrostatic image on the photosensitive drum 25. A device 27, a developing device 28 for developing an electrostatic image formed on the photosensitive drum 25, and a transfer device for transferring a visible image formed on the photosensitive drum 25 to a transfer paper (recording medium) (not shown). 30, a separation device 31 for separating the transfer paper from the photosensitive drum 25, a cleaning device 32 for wiping off the developer remaining on the photosensitive drum 25, paper feeding devices 33 to 35, a registration roller 36, a transfer roller A transporting device 37 that transports the paper, a fixing device 38 that fixes the visible image transferred onto the transfer paper, and a tray 39 on which a copy is placed are provided.

  In the present embodiment, the photosensitive drum 25, the charging device 26, the laser beam scanning device 27, the developing device 28, the transfer device 30 and the fixing device 38 constitute an image forming unit.

  The laser beam scanning device 27 includes a semiconductor laser unit (not shown) fixed to the side surface of the casing of the copying machine 10, a cylindrical lens (not shown) provided at a predetermined position on the output side of the semiconductor laser unit, A polygon mirror 42 provided at the center on one end side, a polygon motor 43 for rotating the polygon mirror 42, an fθ lens 44 provided slightly on the polygon mirror 42 side from the substantially central position of the case, and the other end of the case It is composed of a reflecting mirror 45 provided on the side, a dustproof glass 46 provided on the lower part of the reflecting mirror 45 of the casing, and the like.

  Further, a document scale 51 for aligning one end of the document on the contact glass 14 is provided on one end side of the contact glass 14. A part of the back surface of the document scale 51 has illuminance on the surface of the CCD sensor 22 and CCD. A white reference plate 52 that corrects output variations of each pixel of the sensor 22 (shading correction) is provided (see FIG. 3), and the white reference plate 52 is an upper surface on one end side of the contact glass 14 (substantially the same surface as the document surface). The position 54 is provided. When reading is started, the first carriage 61 and the second carriage 62 are stopped at the above-described HP position.

  Then, prior to reading the document placed on the contact glass 14, it is determined that a predetermined distance has passed from the HP, and the constant width of the white reference plate 52 is read by the CCD sensor 22.

  The analog image signal obtained by reading with the CCD sensor 22 in this way is applied to the image processing circuit on the circuit board 23 to perform shading correction. In this shading correction, the entire effective range (several tens to several hundred lines) of the white reference plate 52 is read, and the data is averaged to obtain correction data.

  As shown in FIG. 3A, the contact glass 14 has an area large enough to read A3 size, and the sub-scanning direction of the first carriage 61 and the second carriage 62 is an arrow. B direction.

  FIG. 3B shows a cross section of the contact glass 14 in a direction perpendicular to the sub-scanning direction of the first carriage 61 and the second carriage 62, and is a cross-sectional view taken along line AA in FIG. is there. However, the document scale 51 is omitted in FIG.

In this embodiment, as shown in FIGS. 3 and 4, the chamfered portion 14 a and the chamfered portion are located on one ridge line of the contact glass 14 in the direction perpendicular to the sub-scanning direction of the first carriage 61 and the second carriage 62. A black mylar (light-shielding means) 71 is attached to a side surface portion 14b that is continuous to 14a and is perpendicular to the sub-scanning direction of the first carriage 61 and the second carriage 62.
The black mylar 71 is made of a member having a transmittance of about 15%, which has been subjected to a matte treatment on the surface, and is bent at substantially the same angle as the chamfering angle of the contact glass 14.

  Further, a double-sided tape 72 is attached to the back surface of the black mylar 71 as indicated by a one-dot chain line, and the black mylar 71 is attached to the chamfered portion 14 a of the contact glass 14 by the double-sided tape 72, so that contact glass is obtained. One end of 14 is shielded from light. FIG. 3 shows a state immediately before the black mylar 71 is attached to the chamfered portion 14 a of the contact glass 14.

Next, the overall operation of the copying machine 10 will be described.
When reading a document, first, a set document is extracted and conveyed by the automatic document feeder 13 and placed on the contact glass 14. Thereafter, the first carriage 61 moves forward at a constant speed, and the second carriage 62 moves forward following the first carriage 61 at half the speed of the first carriage 61. For this reason, the document on the contact glass 14 is optically scanned.

  Next, the original on the contact glass 14 is illuminated by a light source or the like, and the reflected light image is guided to the optical lens 21 through the first mirror 17, the second mirror 18, and the third mirror 19. An image is formed on the CCD sensor 22. The CCD sensor 22 photoelectrically converts the reflected light image of the imaged document to obtain an analog image signal, and the document is read.

  Then, after the reading of the document is completed, the first carriage 61 and the second carriage 62 are moved back to the home position HP position. After the copying is finished, the original on the contact glass 14 is discharged by the automatic document feeder 13 and the next set original is extracted and conveyed by the automatic document feeder 13 to be contact glass 14. Placed on top. In this way, the original is read one after another.

  The analog image signal output from the CCD sensor 22 is converted into a digital image signal by an analog / digital converter mounted on the circuit board 23, and various image processing is performed by the image processing circuit mounted on the circuit board 23. (Binarization, multi-value processing, gradation processing, scaling processing, editing processing, etc.) are performed.

  Next, the document copying operation of the copying machine 10 will be described. During the copying operation, in the printer unit 12 of the digital copying machine, the photosensitive drum 25 is rotationally driven by the driving unit, so that it is uniformly charged by the charging device 26.

  Further, the digital image signal subjected to the image processing by the image processing circuit mounted on the circuit board 23 is converted into an electrostatic image on the photosensitive drum 25 by the laser beam scanning device 27. The operation of the laser beam scanning device 27 will be described. The laser beam emitted from the semiconductor laser in the semiconductor laser unit 40 is converted into a parallel light beam by the collimating lens in the semiconductor laser unit 40 and is provided in the semiconductor laser unit 40. By passing through the aperture, the light beam is shaped into a fixed shape.

  This light beam is compressed in the sub-scanning direction by a cylindrical lens and is incident on the polygon mirror 42. The polygon mirror 42 has an accurate polygon shape, and is driven to rotate at a constant speed by a polygon motor 43 in a constant direction. The rotation speed of the polygon mirror 42 is determined by the rotation speed of the photosensitive drum 25, the writing density of the laser beam scanning device 27, and the number of surfaces of the polygon mirror 42. The laser beam incident on the polygon mirror 42 from the cylindrical lens is deflected by the reflection surface of the polygon mirror and enters the fθ lens 44. The fθ lens 44 converts the scanning light having a constant angular velocity from the polygon mirror 42 so as to be scanned at a constant velocity by the photosensitive drum 25, and the laser beam from the fθ lens 44 passes through the reflecting mirror 45 and the dustproof glass 46. An image is formed on the photosensitive drum 25. The fθ lens 44 also has a surface tilt correction function.

  Further, the laser beam that has passed through the fθ lens 44 is reflected by the synchronization detection mirror outside the image area and guided to the synchronization detection sensor. A synchronization signal serving as a reference for cueing in the main scanning direction is obtained from the detection output of the synchronization detection sensor. In this way, an electrostatic image is formed on the photosensitive drum 25 by the laser beam scanning device 27.

  Then, the electrostatic image on the photosensitive drum 25 is transferred onto a transfer sheet by the transfer device 30. Thereafter, the transfer paper is separated from the photosensitive drum 25 by the separation device 31 and then conveyed to the developing device 38 by the conveyance device 37. This transfer paper is developed by the developing device 38 and discharged as a copy onto the tray 39. Further, the photosensitive drum 25 is cleaned by the cleaning device 32 after separating the transfer paper, and the residual toner is removed. The copying machine 10 creates a copy through such work.

  On the other hand, each time a document is conveyed one by one by the automatic document feeder 13, the CCD sensor 22 moves within the effective range of the white reference plate 52 by moving the first carriage 61 from the HP position in the sub-scanning direction. Read and perform shading correction.

In this embodiment, the sub-scanning direction is one ridge line direction of the contact glass 14 forming the vertical chamfer 14 a Contact and the side surface portion 14b transmittance of 15% of the first carriage 61 and second carriage 62 Since the black mylar 71 is attached, the amount of light from the reflecting mirror 16 passing through the chamfered portion 14 is reduced by about 85 %, and the end side of the white reference plate 52 (range B in FIG. 4) is brightened. Therefore, it is possible to perform good shading correction, and it is possible to read a document satisfactorily while preventing an increase in size and manufacturing cost of the image reading device 11. As a result, it is possible to form a good image on the transfer paper while preventing an increase in the size and manufacturing cost of the copying machine 10.

  In this embodiment, the transmittance of the black mylar 71 is set to 15%. However, in this case, the chamfered portion 14a has a variation in size, the black mylar 71 has a size, and variations in pasting. As a result, the required light is blocked too much, and as shown by the broken line in FIG. 4, the output distribution becomes dark when the end side (range B in FIG. 4) of the white reference plate 52 is read through the chamfered portion 14a. May occur.

  For this reason, the problem that the reading range B of the white reference plate 52 becomes brighter or darker is solved by setting the light shielding amount of the black mylar 71 to a transmittance of 30% to 70% in consideration of the above-described variation. May be.

  Further, when the black mylar 71 is pasted, the parts cost and the pasting cost of the black mylar 71 are incurred, so instead of the black mylar 71, for example, something like black oily magic is applied to the chamfered portion 14a. May be. In this way, the manufacturing cost of the copying machine 10 can be reduced by the amount that the black mylar 71 is unnecessary.

  Further, in the manufacturing process of the contact glass 14, the chamfered portion 14a may be ground glass by masking, sandblasting or the like. In this way, it is possible to suppress work variations such as dirt and uneven coating that occur during the magic coating process.

However, in the case of frosted glass processing, the process of performing the processing becomes complicated (masking, sandblasting, etc.), leading to an increase in cost. To eliminate this, abrasive grains for glass grinding performed when chamfering the contact glass 14 are performed. For example, the surface of the chamfered portion 14a may be roughened by roughening the surface.
In the present embodiment, the first carriage 61 and the second carriage 62 are continuous with the chamfered portion 14a and the chamfered portion 14a on the one ridge line of the contact glass 14 in the direction perpendicular to the sub-scanning direction, and the first carriage 61 The black mylar (light shielding means) 71 is attached to the side surface portion 14 b perpendicular to the sub-scanning direction of the carriage 61 and the second carriage 62. The black mylar 71 is the same as that of the first carriage 61 and the second carriage 62. You may provide only in the chamfer 14a in the one ridgeline of the contact glass 14 of the direction perpendicular | vertical to a subscanning direction.

FIG. 5 is a diagram showing a second embodiment of the image reading apparatus and the image forming apparatus according to the present invention. The same reference numerals are given to the same components as those in the first embodiment, and the description will be omitted. In this embodiment, the shape of the chamfered portion of the contact glass is different from that of the first embodiment, and the other configurations are the same.
In FIG. 5, a chamfered portion 14 c is formed on one end side of the contact glass 14, and the chamfered portion 14 c is recessed in a substantially arc shape toward the inside of the contact glass 14.

  In the present embodiment, since the chamfered portion 14c that is recessed in a substantially arc shape toward the inside of the contact glass 14 is formed on one end side of the contact glass 14, the light that has passed through the chamfered portion 14c is radiated as indicated by arrows. Spreading and preventing an increase in the amount of light when reading the end portion side (range B in FIG. 4) of the white reference plate 52 can be performed, and good shading correction can be performed. Documents can be read satisfactorily while preventing increase in manufacturing cost and manufacturing cost.

  In this embodiment, since a shielding means such as black mylar is not required, the number of parts can be reduced and the manufacturing cost of the copying machine 10 can be reduced, and the amount of light on the end side of the white reference plate 52 can be reduced. Can be prevented from decreasing.

FIG. 6 is a diagram showing a third embodiment of the image reading apparatus and the image forming apparatus according to the present invention. The same reference numerals are given to the same components as those in the first embodiment, and the description will be omitted. In this embodiment, the shape of the chamfered portion of the contact glass is different from that of the first embodiment, and the other configurations are the same.
In FIG. 6, a chamfered portion 14 d is formed at the end of the contact glass 14, and the chamfered portion 14 d protrudes in a substantially arc shape toward the outside of the contact glass 14.

  The chamfered portion 14d has a center of curvature (contact glass 14) when the distance between one end of the contact glass 14 and the end of the white reference plate 52 on the contact glass 14 side is S, and the thickness of the contact glass 14 is t. The distance x from the edge of the contact glass 14 and the distance y from the lower surface of the contact glass 14 are in a relationship of (x, y) <(S / 2, t / 2).

  In the present embodiment, the light from the reflecting mirror 16 that passes through the chamfered portion 14d is collected at the center of curvature (x, y) as indicated by the arrow, and then goes in the diffusion direction. Since the center of curvature (x, y) of the chamfered portion 14c is in the relationship of (x, y) <(S / 2, t / 2), as shown in FIG. The light can be diffused without condensing, and the amount of light can be prevented from increasing when the end side (range B in FIG. 4) of the white reference plate 52 is read, and good shading correction is performed. Thus, it is possible to read a document satisfactorily while preventing an increase in the size and manufacturing cost of the image reading apparatus 11.

  In this embodiment, since a shielding means such as black mylar is not required, the number of parts can be reduced and the manufacturing cost of the copying machine 10 can be reduced, and the amount of light on the end side of the white reference plate 52 can be reduced. Can be prevented from decreasing.

  As described above, the image reading apparatus and the image forming apparatus according to the present invention can read an original satisfactorily while performing an optimal shading correction while preventing an increase in size and manufacturing cost. As an image reading apparatus that reads a document placed on contact glass such as a copying machine, a facsimile machine, or a scanner apparatus using a moving optical system, and an image forming apparatus equipped with the image reading apparatus Useful.

1 is a diagram illustrating a first embodiment of an image reading apparatus and an image forming apparatus according to the present invention, and is a schematic configuration diagram of a copier as an image forming apparatus. 1 is a schematic configuration diagram of an image reading apparatus according to a first embodiment. (A) is a perspective view of the contact glass of 1st Embodiment, (b) is the arrow AA cross section figure of the same figure (a). It is a figure which shows the output distribution of the CCD sensor on the white reference board of 1st Embodiment. It is a figure which shows 2nd Embodiment of the image reading apparatus and image forming apparatus which concern on this invention, and is a figure which shows contact glass and a white reference board. It is a figure which shows 3rd Embodiment of the image reading apparatus and image forming apparatus which concern on this invention, and is a figure which shows a contact glass and a white reference board. It is a schematic block diagram of the principal part of the conventional image reading apparatus. It is a figure which shows the state which irradiates light to a white reference board through the chamfer part of contact glass. It is a figure which shows the state which irradiates light to a white reference board through parts other than the chamfering part of contact glass. It is a figure which shows distribution of the light quantity irradiated to a white reference board in the case where light is irradiated to a white reference board through the chamfer part of contact glass, and the case where light is irradiated to a white reference board through parts other than a chamfer part. It is a figure which shows the output distribution of the CCD sensor on the conventional white reference board.

Explanation of symbols

10 Copying machine (image forming device)
DESCRIPTION OF SYMBOLS 11 Image reader 14 Contact glass 14a, 14c, 14d Chamfer part 15 Illumination lamp (light source)
16 Reflector (light source)
22 CCD sensor (imaging means)
25 Photosensitive drum (image forming means)
26 Charging device (image forming means)
27 Laser beam scanning device (image forming means)
28 Developing device (image forming means)
30 Transfer device (image forming means)
38 Fixing device (image forming means)
52 White reference plate 61 First carriage (holding means)
62 Second carriage (holding means)
71 Black Mylar (shielding means)

Claims (2)

A light source for exposing a document placed on the contact glass;
Holding means that folds the reflected light from the light source and the document and guides it to an optical lens, and holding means movable in a predetermined scanning direction with respect to the contact glass;
Imaging means for photoelectrically converting an image formed by the optical lens to read an image of a document;
In an image reading apparatus provided with a white reference plate that is provided on one end side of a contact glass surface that comes into contact with the original and performs shading correction of the imaging unit,
A chamfered portion is provided on at least one ridge line of the contact glass in a direction perpendicular to the scanning direction of the holding means,
The image reading apparatus , wherein the chamfered portion is recessed in a substantially arc shape toward the inside of the contact glass . With mounting the image reading apparatus according to claim 1, an image forming equipment, characterized by comprising an image forming means for forming an image on a recording medium.

Images