JP6245855B2 - Image reading apparatus and image forming apparatus having the same - Google Patents

Description

  The present invention relates to an image reading apparatus, and is suitable for a digital copying machine, an image scanner, and the like.

  2. Description of the Related Art Conventionally, light emitting diodes (hereinafter referred to as “LEDs”) that are excellent in durability and light utilization efficiency have been used in illumination units included in image reading apparatuses. In Patent Document 1, by using an illumination unit having a configuration in which LED light sources are provided at both ends in the longitudinal direction of the light guide (hereinafter referred to as a both-end type), illuminance can be increased and illuminance unevenness can be reduced. An image reading apparatus is disclosed.

JP 2012-160940 A

  However, the double-sided illumination unit described in Patent Document 1 requires a space for providing a light source at both ends of the light guide, and thus the image reading apparatus is increased in size. In addition, when reading a thick document, the user operates the image reading apparatus with the document plate open, so that the illumination light from the illumination unit is incident on the user's eyes and the user is dazzled. (Discomfort) may be given.

  Therefore, an object of the present invention is to provide an image reading apparatus that is compact and can suppress illumination light from an illumination unit from entering the eyes of a user.

In order to achieve the above object, an image reading apparatus according to an aspect of the present invention includes a document table on which a document is placed, an illumination unit that illuminates the document, and a first light that receives light from the document. and long linear sensor in the direction, and the document pressing plate for pressing the original document on the document table, and a hinge portion for opening and closing the document pressing plate, the illumination unit, the first direction to a long light guide When provided with a light source disposed only on the side of the hand in the first direction of the light guide member, only light incident from the side of the first said hand which definitive in the direction of the light guide body The document is illuminated, and the hinge portion is disposed on the side opposite to the light source in the first direction.

  Further objects and other features of the present invention will become apparent from the preferred embodiments described below with reference to the accompanying drawings.

  According to the present invention, it is possible to provide an image reading apparatus that is compact and capable of suppressing the illumination light from the illumination unit from entering the eyes of the user.

1 is a schematic diagram of a main part of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a cross-sectional view of a main part of the carriage according to the embodiment of the invention. 1 is a cross-sectional view of a main part of an image reading apparatus according to Embodiment 1 of the present invention. The figure which shows the illumination intensity distribution in Example 1 of this invention. FIG. 6 is a cross-sectional view of a main part of an image reading apparatus according to a comparative example. The figure which shows the illumination intensity distribution in a comparative example. FIG. 6 is a cross-sectional view of a main part of an image reading apparatus according to a second embodiment of the present invention. The figure which shows the illumination intensity distribution in Example 2 of this invention.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In addition, in each figure, the same reference number is attached | subjected about the same member and the overlapping description is abbreviate | omitted.

  FIG. 1 is a main part schematic diagram of an image forming apparatus 1000 including an image reading apparatus 100 and an image forming unit 200 according to the present embodiment. The user can give an operation instruction to the image forming apparatus 1000 through the operation unit 102 while confirming the display on the display unit 101. The image reading apparatus 100 according to the present embodiment can read an A3 document, and the size of the reading range (illumination range) is about 300 mm × 420 mm.

  The image reading apparatus 100 includes a document table 104 for placing the document 103, a document pressure plate 105 for pressing the document 103 against the document table 104, a holding unit 108 that holds the document table 104, and a lower part of the document table 104. The carriage 300 is disposed at the same position. In the present embodiment, the document table 104 is made of glass, the document pressure plate 105 is provided on the holding unit 108 via the hinge unit 106, and the carriage 300 moves in the X direction (sub-scanning direction) to move the document. 103 can be scanned.

  FIG. 2 is a ZX sectional view of the carriage 300. The carriage 300 includes a housing 301, an illumination unit 310 that illuminates the original 103, a linear sensor 304 that receives light from the original 103, and an optical unit 303 that guides light from the original 103 to the linear sensor 304. Further, a plurality of mirrors 302 that reflect the reflected light from the original 103 are arranged on the optical path between the original 103 and the optical unit 303. In the present embodiment, the optical unit 303 is a reduced imaging system, and the linear sensor 304 is a line sensor extending in the Y direction (perpendicular to the paper surface) (pixels are one-dimensionally arranged in the Y direction).

  The document image formed on the linear sensor 304 is transmitted to the controller 305 as one-dimensional image information. The controller 305 receives the one-dimensional image information every time the carriage 300 reads the document 103, and acquires the two-dimensional image information from the obtained plurality of information. Further, the controller 305 corrects information such as the color and contrast of the image, converts the information into a signal, and transmits the signal to the image forming unit 200. The image forming unit 200 forms an image on a recording medium such as paper in accordance with a signal received from the controller 305 based on an electrophotographic method, an inkjet method, or the like.

Here, the illumination unit 310 according to the present embodiment has only a light guide extending in the longitudinal direction (first direction) of the linear sensor 304 and one end in the longitudinal direction (first direction) of the light guide. An arranged light source. Thereby, compared with a both-end type, the image reading apparatus 100 can be reduced in size and an installation area can be made small. Furthermore, the image reading apparatus 100 according to the present embodiment employs a configuration in which a hinge portion 106 for opening and closing the document pressure plate 105 is disposed on the side opposite to the light source in the longitudinal direction of the light guide. According to this structure, it can suppress that the illumination light from the illumination part 310 injects into a user's eyes (details are mentioned later).

  Next, the image reading apparatus 100 according to the present embodiment will be described in detail in each example.

[Example 1]
The image reading apparatus according to the first embodiment of the present invention will be described in detail below. FIG. 3 is a schematic diagram (YZ sectional view) of a main part of the image reading apparatus 100 according to the present embodiment. The illumination unit 310 according to the present embodiment includes a light source (LED) 312 mounted on a substrate 313 and a light guide 311 having an incident surface on the light source 312 side. A heat sink 314 for exhausting heat generated by the light source 312 is provided on the back surface of the substrate 313 (the surface opposite to the surface on which the light source 312 is provided). The light guide 311 is disposed such that its longitudinal direction coincides with the Y direction (main scanning direction).

  As shown in FIG. 3, the illumination unit 310 has a configuration (hereinafter referred to as a one-end type) including a light source 312 only at one end in the longitudinal direction of the light guide 311 (end on the −Y side). . In the one-end type, since the light source 311 does not include a light source, a substrate, or a heat sink at the other end in the longitudinal direction (the end on the + Y side), the width of the holding unit 108 in the Y direction is shorter than that of the both-end type. The image reading apparatus 100 can be downsized.

  The light guide 311 includes an optical surface (secondary light source surface) 315 including a plurality of fine prisms (secondary light source group) arranged in the Y direction at the bottom. The optical surface 315 behaves as if it is a light source that emits light itself. This action is due to total reflection, and as a result, the light emitted from the optical surface 315 has a characteristic that it travels with an angular distribution biased away from the light source 312 (hereinafter referred to as a declination characteristic). doing. Here, in this embodiment, the light reflected by the optical surface 315 has a declination characteristic that proceeds only in the + Y direction. The inventor paid attention to the declination characteristic in this one-end type, and found that the effect of providing a fine prism is small in the vicinity of the + Y side end of the light guide 311.

  Therefore, the light guide 311 according to the present embodiment employs a configuration having a region where the fine prism is not provided on the bottom surface of the end portion on the side opposite to the light source 312 (+ Y side). Further, in the longitudinal direction (Y direction) of the light guide 311, the distance between the central axis 321 of the optical surface 315 and the light source 312 is shorter than the distance between the optical axis 306 and the light source 312 defined by the optical unit 303. ing. That is, the central axis 321 of the optical surface 315 is intentionally shifted toward the light source 312 with respect to the optical axis 306 of the optical unit 303. With this configuration, the light guide 311 can be reduced in size. Furthermore, when the light guide 311 including the fine prism is molded by resin, the processing area in the mold can be reduced, so that wear of the cutting tool can be suppressed, and high accuracy and low cost can be realized.

  Note that, as in the image reading apparatus 100 according to the present embodiment, the reduced image forming method using the reduced image forming system is compared with the contact reading method using the same-magnification optical system (Contact Image Sensor method). The depth of field is deep. Therefore, according to the reduced image formation method, even if the document is lifted from the document table, sufficient contrast performance can be obtained if the lift is about several tens of millimeters. Further, a general image reading apparatus is required to maintain high illuminance and uniformity even when a document is large (several tens of millimeters or more).

  Here, on the document table 104 (irradiation height is 0 mm), illumination is performed over the entire range from the end on the light source 312 side (−Y side) to the end on the side opposite to the light source 312 (+ Y side). Illuminated substantially uniformly by the portion 310. However, as described above, since the light reflected by the optical surface 315 has a declination characteristic directed only in the + Y direction, the light amount distribution of the illumination light is opposite to the light source 312 (+ Y as the irradiation height increases). Side). In other words, due to the above-described declination characteristic, the amount of illumination light greatly decreases as the irradiated height increases on the light source 312 side in the Y direction.

  Therefore, in this embodiment, the abutting portion 307 that determines the position of the document in the Y direction is provided at the end of the light guide 311 opposite to the light source 312 in the Y direction (+ Y side). ing. With this configuration, the document can be placed away from the light source 312 side in the Y direction of the document table 104. Therefore, coupled with the above-described declination characteristic of the one-end type, a substantially constant light amount can be obtained even if the irradiated height changes. Can be maintained. Therefore, even when the document is lifted from the document table 104, the uniformity of the illuminance of the light that illuminates the document can be maintained.

  FIG. 4 is a diagram illustrating an illuminance distribution when the light source 312 provided at one end of the light guide 311 is caused to emit light in the image reading apparatus 100 according to the present embodiment. In FIG. 4, the horizontal axis indicates the reading position (main scanning reading position) in the Y direction, and the vertical axis indicates the illuminance ratio of light received by the linear sensor 304 (relative value of illuminance when the peak value is 100%). Show. Also, each curve represents the amount of lifting (illuminated height) of the original surface (irradiated surface) of the original 103 placed in the reading range (illuminated range by the illumination unit 310) on the original table 104 from the original table 104. ).

  In the reduced imaging method, the received light amount at the end of the linear sensor 304 is reduced by the angle-of-view characteristic (COS fourth law) of the optical unit 303 even when the document 103 is not lifted. There are challenges. In order to deal with this problem, in this embodiment, by appropriately arranging the fine prisms in the light guide 311, as shown in FIG. 4, the illuminance ratio when the irradiated height is 0 mm is spread over the entire reading range. It is almost uniform across.

  However, as shown in FIG. 4, as the irradiation height increases, the illuminance ratio at one end of the reading range (the end on the −Y side) decreases, and when the irradiation height reaches 40 mm, It can be seen that the illuminance ratio at the end on the -Y side is about 20%. However, in general, it is particularly easy for the floating to occur in a binding portion in a thick document such as a dictionary, and the width of these documents in the Y direction is often around 260 mm.

  Therefore, when the above-described document is abutted against the abutting portion 307 according to the present embodiment and placed on the document table 104, the main document range shown in FIG. 4 is read. At this time, it can be seen from FIG. 4 that the illuminance ratio is substantially uniform over the entire area of the main document at any irradiation height. As described above, in this embodiment, the abutting portion 307 is provided on the other end (+ Y side end) of the reading range, that is, on the side opposite to the light source 312, so that the illuminance at the −Y side end described above. It is possible to avoid the influence due to the decrease in the ratio.

  In the present embodiment, the abutting portion 307 is disposed on the holding portion 108. However, if the location can position the document in the Y direction, such as on the document table 104, the abutting portion. 307 may be arranged anywhere. Further, the abutting portion 307 according to the present embodiment is arranged so that the surface (abutting surface) that contacts the document is along the direction (X direction) perpendicular to the longitudinal direction (Y direction) of the light guide 311. ing. In other words, the abutting portion 307 has a continuous abutting surface whose longitudinal direction is along the X direction. However, the term “perpendicular” here includes “substantially vertical”, and the abutting surface may not be arranged strictly along the X direction as long as the original can be positioned in the Y direction. , It does not have to be a continuous surface.

  Further, in the image reading apparatus 100 according to the present embodiment, as shown in FIG. 3, a hinge portion 106 for opening and closing the document pressure plate 105 is provided on the side opposite to the light source 312 (+ Y side) in the Y direction. ing. With this configuration, the user inevitably stands on the light source 312 side and opens and closes the document pressure plate 105. At this time, the illumination light reflected by the optical surface 315 is directed only in the + Y direction in combination with the above-described declination characteristic in the one-end type, so that the illumination light is prevented from entering the user's eyes. it can. When reading a document such as the above-described dictionary, since all the documents are smaller than the A3 width, the amount of illumination light leaking from the reading range is increased, so that a greater effect can be obtained.

  As shown in FIG. 1, the controller 305 provided in the image forming apparatus 1000 is disposed on the hinge portion 106 side (+ Y side), that is, on the opposite side to the user side (−Y side). This is because the display unit 101 and the operation unit 102 exist on the user side, and a space for replenishing toner, ink, paper, and the like in the image forming unit 200 is necessary, and the controller 305 can be disposed. This is because it is difficult.

  Therefore, in general, in order to shorten the connection distance between the electrical components such as the light source 312 provided in the illumination unit 310 and the controller 305, it is preferable in terms of design to arrange the electrical components on the + Y side similarly to the controller 305. . However, in the image forming apparatus 1000 including the image reading apparatus 100 according to the present embodiment, the electric component such as the light source 312 is intentionally disposed on the user side (−Y side) opposite to the controller 305, thereby the above-described. Has achieved the effect.

  In addition, as shown in FIG. 3, the user can easily recognize the position of the abutting portion 307 visually by coloring the abutting portion 307 with a color different from that of the adjacent member such as the holding portion 108. Thus, accurate positioning of the document can be promoted. The abutting portion 307 may be colored as a whole or partially (as a pattern or a character).

  Further, when the length of the illumination range (reading range) of the illumination unit 310 in the longitudinal direction (Y direction) of the light guide 311 is 250 mm or more, the above-described problems (illuminance unevenness and illumination light leakage) are particularly large. Thus, a greater effect of the present invention can be obtained. In this embodiment, since the size of the illumination range is about 300 mm × 420 mm so that the A3 original can be read, the effect of the present invention can be sufficiently obtained.

  As described above, according to the image reading apparatus according to the present embodiment, the installation area can be reduced by downsizing the apparatus, and the illumination light from the illumination unit can be prevented from entering the eyes of the user. it can.

[Comparative example]
Here, the comparative example with respect to Example 1 of this invention is demonstrated. FIG. 5 is a schematic view (YZ cross-sectional view) of a main part of an image reading apparatus 400 according to this comparative example. This comparative example is different from the first embodiment in that the image reading apparatus 400 includes a double-sided illumination unit 410 and a fine prism is provided over the entire bottom surface of the light guide 411. It is that. That is, the illumination unit 410 includes the light source 412, the substrate 413, and the heat sink 414 at both ends in the longitudinal direction (Y direction) of the light guide 411, and the central axis of the optical surface 415 is optical. The configuration coincides with the optical axis 306 of the unit 303.

  First, FIG. 6A shows the illuminance distribution when only the light source 412 provided at the + Y side end of the light guide 411 is caused to emit light in the image reading apparatus 400 according to this comparative example. The same is shown. Note that the illuminance distribution when only the light source 412 at the end portion on the -Y side emits light coincides with the illuminance distribution of FIG. In the illuminance distribution shown in FIG. 6A, the center of gravity moves away from the + Y side end as the irradiated height increases due to the declination characteristic caused by emitting only the light source 412 on the + Y side. . In particular, the illuminance ratio rapidly decreases in the vicinity of the light source 412, and when the irradiated height is 40 mm, the illuminance ratio at the end of the reading range is about 25%.

  Therefore, in the present comparative example, the light source 412 provided at both ends of the light guide 411 is caused to emit light at the same time, so that the illuminance distribution shown in FIG. The illuminance distribution as shown in FIG. As can be seen from FIG. 6B, when the irradiated height is 0 mm, the illuminance ratio is substantially uniform over the entire main reading range as in the first embodiment. In addition, compared with the illuminance distribution shown in FIG. 6A, the illuminance distribution shown in FIG. 6B improves the illuminance ratio at both ends of the reading range when the document is lifted. Yes.

  However, in this comparative example, the decrease in the illuminance ratio at both ends of the reading range due to the increase in the irradiation height cannot be completely suppressed. For example, when the irradiation height is 40 mm, both ends of the reading range are detected. The illuminance ratio at the part is about 50%. Therefore, in the image reading apparatus 400 according to this comparative example, even if the abutting portion 407 is provided on the opposite side (+ Y side) to the light source 412 at the −Y side end in the Y direction, as in the first embodiment. The illuminance distribution in the main document range becomes non-uniform. Although it is possible to reduce the influence of a decrease in the illuminance ratio by disposing the document away from the abutting unit 407, it is not practical because the document cannot be positioned by the abutting unit 407.

  When a document is read using the double-sided illumination unit 410 as in this comparative example, various effects are exerted on the read image due to the uneven illuminance described above. For example, when a manuscript such as a dictionary with a white paper color is read as a color image or gray scale image having gradation, the read image near the edge of the binding portion has unevenness that changes from white to gray. It will occur. In addition, when read as a black and white binary image without gradation, the background (unprinted portion) near the edge of the binding portion is read as black, and characters written in the same portion are buried. There is a possibility.

  As shown in FIG. 5, in the illumination unit 410 according to this comparative example, each of the light emitted from the −Y side end and the + Y side end and reflected by the optical surface 415 is −Y And a declination characteristic toward each of the + Y direction. Therefore, in the image reading apparatus 400 according to this comparative example, even if the hinge portion 106 is provided on the opposite side (+ Y side) to the light source 412 at the end portion on the −Y side in the Y direction as in the first embodiment, It cannot suppress that the light which goes to -Y direction injects into a user's eyes.

  As described above, since the illumination unit 410 according to this comparative example is a double-ended type, as in the first embodiment, the area of the optical surface 415 is reduced, or the central axis in the Y direction of the optical surface 415 is set to the optical unit 303. It cannot be shifted with respect to the optical axis 306. Therefore, in this comparative example, the light guide body 411 cannot be reduced in size, and high precision and low cost in the die processing cannot be realized.

[Example 2]
Hereinafter, an image reading apparatus according to the second embodiment of the present invention will be described in detail. FIG. 7 is a schematic view (YZ cross-sectional view) of a main part of the image reading apparatus 500 according to the present embodiment. The difference between the present embodiment and the first embodiment is that the abutting portion 507 provided in the image reading apparatus 500 is disposed on the side opposite to the abutting portion 307 provided in the image reading apparatus 100. That is, in the image reading apparatus 500, the illumination unit 510 includes the light source 512 only at one end in the longitudinal direction of the light guide 511 (end on the −Y side), and the abutting unit 507 is connected to the light source 512 in the Y direction. It is provided on the same side (−Y side).

  As shown in FIG. 7, the illumination unit 510 does not include a light source, a substrate, or a heat sink at the other end in the longitudinal direction of the light guide 511 (the end on the + Y side). Therefore, the width of the holding unit 108 in the Y direction can be shortened compared to the both-end type, and the image reading apparatus 500 can be downsized.

  In this embodiment, the light emitted from the light source 512 and reflected by the optical surface 515 of the light guide 511 has a declination characteristic that proceeds only in the + Y direction as in the first embodiment. Therefore, the light guide 511 according to the present embodiment has a region where no fine prism is provided on the bottom surface of the + Y side end. Further, the central axis 521 in the Y direction of the optical surface 515 is intentionally shifted to the light source 512 side (−Y side) with respect to the optical axis 306 defined by the optical unit 303. With this configuration, similarly to the first embodiment, the light guide 511 can be reduced in size, and the precision and cost reduction in mold processing can be realized.

  Also in this embodiment, similarly to the first embodiment, since the hinge portion 106 is provided on the opposite side (+ Y side) to the light source 512 in the Y direction, the illumination light is combined with the above-described declination characteristics. Can be prevented from entering the eyes. Also in the image forming apparatus 1000 including the image reading apparatus 500 according to the present embodiment, the electric components such as the light source 512 are intentionally arranged on the user side (−Y side) opposite to the controller 305, so that The effect which was done can be acquired.

  FIG. 8 is a diagram showing the illuminance distribution when the light source 512 provided at one end of the illumination unit 510 emits light in the image reading apparatus 500 according to the present embodiment, as in FIG. 4. As shown in FIG. 8, the illuminance ratio when the irradiated height is 0 mm is substantially uniform over the entire reading range, but as the irradiated height increases, one end of the reading range (−Y side) The illuminance ratio at the end of

  In this embodiment, since the abutting portion 507 is provided on the −Y side end of the reading range, that is, on the same side as the light source 512, when the document is lifted, the −Y side end in the main document range. The illuminance ratio at will decrease. However, since the abutting portion 507 is on the user side (−Y side), compared to the first embodiment, the load when the user places the document is reduced, and it is easy to use even for a user with a particularly short height. The effect is obtained.

  As described above, according to the image reading apparatus according to the present embodiment, the installation area can be reduced by downsizing the apparatus, and the illumination light from the illumination unit can be prevented from entering the eyes of the user. it can.

[Modification]
As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

  For example, in the above-described embodiment, the LED is used as the light source. However, the present invention is not limited to this, and an EL light source (such as OLED) or a light bulb may be used as the light source. In the above-described embodiment, a line sensor in which pixels are one-dimensionally arranged is used as the linear sensor, but a plurality of line sensors arranged in the short direction may be used as the linear sensor.

  The material for the document table is not limited to glass, and resin or the like may be used, and the material for the light guide is not limited to resin but may be glass or the like. In addition, the shape of the plurality of fine prisms provided in the light guide may be mountain-shaped or trapezoidal, and the optical surfaces constituting them may be curved surfaces as well as flat surfaces. Furthermore, you may comprise a light guide as plate-shaped members, such as a reflecting plate.

  In each of the above-described embodiments, it is assumed that a thick original (having a binding portion) such as a dictionary or a railway timetable is read. However, the present invention is not limited thereto, and an original or a three-dimensional object with a wavy surface is used. Even when reading, the effect of the present invention can be obtained.

DESCRIPTION OF SYMBOLS 100 Image reading apparatus 104 Document stand 105 Original pressure plate 106 Hinge 303 Optical part 304 Linear sensor 310 Illumination part 311 Light guide 312 Light source

Claims (9)

A document table on which the document is placed;
An illumination unit for illuminating the document;
A linear sensor that is long in a first direction for receiving light from the document;
A document pressure plate that presses the document against the document table;
A hinge portion for opening and closing the document pressure plate;
An image reading apparatus comprising:
The illumination unit is configured with a long light guide in a first direction, and a light source disposed only on the side of the hand in the first direction of the light guide body, definitive in the first direction the and illuminates the document only light incident on the light guide from the hand side,
The image reading apparatus according to claim 1, wherein the hinge portion is disposed on a side opposite to the light source in the first direction.   The image reading apparatus according to claim 1, wherein the light guide has an optical surface including a plurality of prisms arranged in the first direction.   The image reading apparatus according to claim 1, wherein the light guide has an optical surface that is long in the first direction for reflecting light from the light source.   An optical unit that guides light from the document to the linear sensor, and in the first direction, a distance between a central axis of the optical surface and the light source is an optical axis defined by the optical unit and the light source; The image reading apparatus according to claim 2, wherein the image reading apparatus is shorter than the distance between the image reading apparatus and the image reading apparatus.   The image reading apparatus according to claim 4, wherein the optical unit is a reduced imaging system.   6. The image reading apparatus according to claim 1, wherein a length of the illumination range of the illumination unit in the first direction is 250 mm or more. A document table on which the document is placed;
An illumination unit for illuminating the document;
A linear sensor that is long in a first direction for receiving light from the document;
An optical unit for guiding light from the document to the linear sensor;
A document pressure plate that presses the document against the document table;
A hinge portion for opening and closing the document pressure plate;
An image reading apparatus comprising:
The illumination unit includes a light guide that is long in the first direction, and a light source that is disposed only at one end of the light guide in the first direction,
The light guide has a long optical surface in the first direction that reflects light from the light source;
In the first direction, the distance between the central axis of the optical surface and the light source is shorter than the distance between the optical axis defined by the optical unit and the light source,
The image reading apparatus according to claim 1, wherein the hinge portion is disposed on a side opposite to the light source in the first direction.   An image comprising: the image reading apparatus according to claim 1; and an image forming unit that forms an image of the document read by the image reading apparatus on a recording medium. Forming equipment.   A controller that converts information acquired by the image reading device into a signal and transmits the signal to the image forming unit is provided, and the controller is disposed on the side opposite to the light source in the first direction. The image forming apparatus according to claim 8.

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