Image reading device and image forming device

Abstract

To suppress generation of a skew image while reducing damage of a document, which is placed while protruding in a location where a projected shape part and a recessed shape part are fitted to each other, caused by the projected shape part.SOLUTION: An image reading device 5 reads a document, which is fed by an automatic document feeder 20, by an image reading section in an image reading device main body 4 to which the automatic document feeder is attached so as to be opened / closed by a rotating operation. The image reading device comprises alignment means for aligning the automatic document feeder with the image reading device main body by fitting projected shape parts 42F and 42F, which are provided in one of the automatic document feeder and the image reading device main body, into recessed shape parts 43F and 43R, which are provided in the other when the automatic document feeder is closed. The alignment means includes at least two pairs of projected shape parts and recessed shape parts. The at least two pairs of projected shape parts include a movable projected shape part 42F which is held so as to freely move forward and backward and energized in the direction of protrusion and a stationary projected shape part 42R which cannot move forward and backward.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an image reading apparatus and an image forming apparatus.

Background Art

[0002] Conventionally, there is known an image reading apparatus that reads a document conveyed by an automatic document feeder by an image reading unit of an image reading apparatus main body that is attached to the automatic document feeder so as to be openable and closable by a rotation operation.

[0003] For example, Patent Document 1 discloses an image reading apparatus in which a document conveying apparatus (automatic document feeder) that conveys a document so as to pass through an image reading position of a contact glass of a scanner housing (image reading apparatus main body) is attached to the scanner housing so as to be openable and closable. In this image reading apparatus, positioning means is provided to suppress the generation of a skew image caused by a document passing through the image reading position on the scanner housing being conveyed while inclined with respect to a predetermined document conveying direction. This positioning means positions the document conveying apparatus with respect to the scanner housing in a closed state by engaging two engaging portions (convex-shaped portions) of the document conveying apparatus with two positioning engaging portions (concave-shaped portions) of the scanner housing, respectively.

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a conventional image reading apparatus, when reading a document placed on the contact glass of the image reading apparatus main body, the automatic document feeder is closed to hold the document. At this time, if the document protrudes and is placed at a location where the convex-shaped portion and the concave-shaped portion fit together, the convex-shaped portion may contact the document and damage the document.

Means for Solving the Problems

[0005] To solve the above-mentioned problems, the present invention provides an image reading device that reads a document transported by an automatic document feeder using an image reading section of an image reading device body to which the automatic document feeder is mounted so as to be openable and closable by a rotational movement, the image reading device having an alignment means for aligning the automatic document feeder and the image reading device body by having a convex shape provided on one of the automatic document feeder and the image reading device body fit into a concave shape provided on the other when the automatic document feeder is closed, the alignment means comprising at least two sets of the convex shape and the concave shape, the at least two sets of the convex shape include a movable convex shape that is held to move back and forth and biased in the protruding direction, and a fixed convex shape that cannot move back and forth. [Effects of the Invention]

[0006] According to the present invention, it is possible to reduce the damage caused by the convex portion contacting the original document that is placed over the area where the convex portion and the concave portion fit together, while also suppressing the generation of skew images. [Brief explanation of the drawing]

[0007] [Figure 1] A perspective view showing an image forming apparatus according to an embodiment. [Figure 2] An enlarged diagram showing the main components of the image reading device installed in the image reading device. [Figure 3] A perspective view showing the configuration of an alignment means for aligning the ADF and the scanner unit in the planar direction of the contact glass in an embodiment. [Figure 4] (a) is a perspective view when the movable convex part is in the extended position (protruding position). (b) is a cross-sectional view showing the retraction mechanism of the movable convex part when it is in the extended position (protruding position). [Figure 5] (a) is a perspective view when the movable convex part is in the retracted position (non-protruding position). (b) is a cross-sectional view showing the retraction mechanism of the movable convex part when it is in the retracted position (non-protruding position). [Figure 6] (a) is a perspective view showing the concave part into which the convex part fits. (b) is a cross-sectional view of the same concave part. [Figure 7] A cross-sectional view showing how the convex part fits into the concave part. [Figure 8] (a) is a perspective view showing an example in which a protruding part is provided around a recessed part into which a fixed convex part fits. (b) is a cross-sectional view of the same recessed part. [Figure 9] A cross-sectional view showing how the fixed convex part rides on the protruding parts surrounding the concave part. [Modes for carrying out the invention]

[0008] The following describes embodiments of the present invention applied to an image forming apparatus equipped with an image reading device. Figure 1 is a perspective view showing the image forming apparatus 1 of this embodiment. The image forming apparatus 1 shown in Figure 1 combines the functions of a copier, printer, facsimile machine, scanner, etc., and can record and output full-color or monochrome images on recording paper or output them in a predetermined data format based on input data such as scanned image data.

[0009] The image forming apparatus 1 is equipped with an ADF 20, which is an automatic document feeder, above the paper feed unit, scanner unit 4, and image forming unit 15. The scanner unit 4 constitutes the main body of the image reading device and, together with the ADF 20, constitutes the image reading device 5.

[0010] The paper feeding section of the image forming unit 15 includes, for example, multiple paper feeding cassettes, each storing cut-shaped recording paper, and multiple sets of paper feeding rollers that pick up and feed recording paper from any of these paper feeding cassettes. The paper feeding section also has a paper feeding path that includes various rollers, etc., for transporting the recording paper fed from any of the paper feeding rollers to a predetermined image forming position in the image forming unit 15.

[0011] The image forming unit 15 includes, for example, an exposure unit, a plurality of photosensitive drums, a developing device that uses four toners: cyan (C), magenta (M), yellow (Y), and black (K), a transfer belt, a secondary transfer unit, and a fixing unit.

[0012] The image forming unit 15, based on the image read by the image reading device 5, for example, exposes each color photoreceptor drum using an exposure unit to form an electrostatic latent image on each photoreceptor drum, and then develops the image by supplying toner to the latent image on each photoreceptor drum using the developing unit for each color. The image forming unit 15 also performs primary transfer of the toner image on each color photoreceptor drum to a transfer belt, secondary transfer by overlaying it onto recording paper in a secondary transfer unit, and then heats and pressurizes the toner image on the recording paper in a fixing unit to fix it, thereby forming a color image. Furthermore, the image forming unit 15 can form external output images such as image files or data that can be output externally, based on the image read by the scanner unit 4 or the back-side image reading module 35 (second image reading unit) described later. Instead of the electrophotographic image forming unit 15 described above, an image forming unit employing another recording method such as an inkjet method may be used.

[0013] Next, the image reading device 5 will be described. Figure 2 is an enlarged diagram showing the main components of the image reading device 5. The image reading device 5 is configured to be switchable between flatbed scanner mode (placed document reading mode) and DF scanner mode (transported document reading mode).

[0014] The flatbed scanner mode is executed when a scanning start request operation, such as pressing the copy start button, is made with a document placed on the flatbed contact glass 13 at the top of the scanner unit 4. This mode reads the image of the placed document. In this mode, the image reading unit 16 is moved in the movable scanning area 11 directly below the flatbed contact glass 13, and light is shone onto the image surface of the document. The reflected light from the image surface of the document is then converted into an image signal to read the image of the document.

[0015] The DF scanner mode is an operation mode in which the image reading unit 16 is stopped in the stop reading area 12 directly below the DF contact glass 14 to read the image of the conveyed document. In the DF scanner mode, the ADF 20 separates the documents one by one from the stack of documents placed on the document loading tray 21 (document loading table) and conveys them into the document conveyance path 22, and conveys them along the document conveyance path 22. During this conveyance, the document is configured to face the upper surface of the DF contact glass 14 sequentially and partially from the upstream side portion in the conveyance direction.

[0016] The ADF 20 is rotatably attached to the rear portion of the upper surface of the scanner unit 4 (the device back side (rear side)) via a hinge 41 (see FIG. 3), which is an opening / closing mechanism. Thereby, the ADF 20 can take an open position in which it opens on the flatbed contact glass 13 with respect to the scanner unit 4, and a closed position in which it can press the document on the flatbed contact glass 13.

[0017] The image reading unit 16 may be capable of repeatedly line-scanning the image on the surface side of the document at a predetermined image reading position on the contact glasses 13 and 14, such as a CCD module or a CIS module. Further, a fixed image reading unit fixed to the stop reading area 12 and a moving image reading unit that moves along the flatbed contact glass 13 in the moving reading area 11 may be provided respectively.

[0018] A pair of side fences 23 that are movable in the width direction for positioning the document set on the ADF 20 in the document width direction orthogonal to the paper feed direction are attached to the document loading tray 21. These side fences 23 can approach and separate relatively so as to align the center in the document width direction between the document loading tray 21 and the document.

[0019] The ADF20 is covered by a cover 38A that can be opened and closed at least at its upper part. The main guide portion forming the document conveyance path 22 of the ADF20 is formed by ribs or the like formed on the cover 38A. On the other hand, the ADF20 includes a pickup roller 24 that calls the document set on the document placement tray 21 in the paper feeding direction, and a feed roller 25 and a separation pad 43 for sending the document called in the paper feeding direction by the pickup roller 24 toward the document conveyance path 22.

[0020] Further, the ADF20 includes a conveyance unit 27 that conveys the document fed into the document conveyance path 22 by the feed roller 25 in a posture where the document can be image-read on the DF contact glass 14 and conveys the document after image reading to the discharge port 36.

[0021] This conveyance unit 27 reverses the document separated and carried in by the feed roller 25 or the like along the document conveyance path 22 and conveys the document so as to pass through a predetermined reading position on the upper surface of the DF contact glass 14. For such document conveyance, a first conveyance roller 28, a second conveyance roller 29, and a registration sensor 31 for detecting the leading end of the document in the conveyance direction are provided upstream of the DF contact glass 14 in the document conveyance path 22.

[0022] The document separated by the feed roller 25 or the like is conveyed by the first conveyance roller 28 and the second conveyance roller 29 so as to pass over the DF contact glass 14. Then, based on the timing of detecting the leading end of the document by the registration sensor 31, the document surface image is timely read by the image reading unit 16.

[0023] For example, when the leading end of the document is detected by the registration sensor 31, the timing at which the leading end position of the document detectable by the pulse count of the paper feeding motor as the drive source reaches the reading position on the DF contact glass 14 is specified. A gate signal indicating the effective image area in the sub-scanning direction of the surface of the document starts to be transmitted, and the gate signal continues to be transmitted until the trailing end position of the document passes through the reading position.

[0024] When reading the image on the back side of a document is required, the back side image is read by a back side image reading module 35 (second image reading unit) consisting of a contact-type image sensor for back side reading.

[0025] The back-side image reading module 35 includes a light source unit that illuminates the document based on a lighting signal from the control unit, a plurality of sensor chips that receive reflected light from the document, and a plurality of amplification units that amplify the signals output from each sensor chip. The back-side image reading module 35 also includes an A / D conversion unit that converts the signals amplified by the amplification units from analog signals to digital signals, and an image processing unit that performs image processing on the digitally converted signals. Furthermore, this back-side image reading module 35 has an output control circuit that controls the output of signals stored in the frame memory based on timing signals from the control unit, and an interface circuit that outputs signals from the output control circuit to the main unit of the device. The timing of back-side image reading by this back-side image reading module 35 is controlled in substantially the same way as the timing of front-side image reading, and the scanned document is ejected into the output tray 39.

[0026] Downstream of the DF contact glass 14 in the document transport path 22, there is a pair of transport rotating bodies, which are a reading exit roller pair 32, that transports the document with the scanned front side image to the back side image reading module 35. Downstream of the reading exit roller pair 32, there is a white guide member 33, which is a guide part that faces the back side image reading module 35. Furthermore, downstream of the back side image reading module 35 and the white guide member 33, there is a pair of transport rotating bodies, which are a paper discharge roller pair 37.

[0027] The number and location of these transport and paper ejection rollers can be arbitrarily set according to the path setting conditions of the document transport path 22, the length of the transport direction of the smallest size document, etc.

[0028] The back-side image reading module 35 uses a contact-type image sensor with a shallow depth of field, and transports the back side of the document while keeping it in contact with the glass surface of the back-side image reading module 35. As a result, paper dust and toner from the document adhere to the glass surface of the back-side image reading module 35, making the glass surface prone to contamination. Therefore, contamination of the glass surface may cause abnormalities such as black streaks in the image read by the back-side image reading module 35. Consequently, periodic cleaning of the glass surface is necessary.

[0029] Figure 3 is a perspective view showing the configuration of the alignment means for aligning the ADF 20 and the scanner unit 4 in the planar direction of the contact glasses 13 and 14 in this embodiment. In DF scanner mode (document transport mode), the positional accuracy between the ADF 20, which transports the document, and the scanner unit 4, which has an image reading unit 16, is important. If the document transported by the ADF 20 is transported at an angle from a predetermined transport direction (a direction perpendicular to the reading line L of the scanner unit 4), the document will be transported diagonally with respect to the reading line L of the scanner unit 4, and the scanned image will be tilted by that amount, i.e., a skewed image.

[0030] Generally, the hinge 41 for opening and closing the ADF 20 relative to the scanner unit 4 has some play, which can cause misalignment between the ADF 20 and the scanner unit 4 when the ADF 20 is closed (misalignment of the contact glasses 13 and 14 in the planar direction; the same applies hereinafter). Therefore, a means for aligning the ADF 20 and the scanner unit 4 is necessary.

[0031] One possible alignment method is to employ a configuration in which, when the ADF 20 is closed, the convex portions 42F and 42R provided on the ADF 20 fit into the concave portions 43F and 43R provided on the scanner portion 4, thereby aligning the ADF 20 and the scanner portion 4. In this alignment method, when the ADF 20 is closed, the convex portions 42F and 42R fit into the concave portions 43F and 43R, thus aligning the ADF 20 and the scanner portion 4. This suppresses the generation of skewed images in DF scanner mode.

[0032] However, in flatbed scanner mode (placed document scanning mode) where a document is placed on the flatbed contact glass 13 of the scanner unit 4, if the document is placed so that it extends beyond the area where the convex parts 42F, 42R and concave parts 43F, 43R fit together, the convex parts 42F, 42R will come into contact with the document when the ADF 20 is closed. This causes the convex parts 42F, 42R to push the document into the concave parts 43F, 43R, potentially damaging the document.

[0033] In particular, if the hinge 41 has a general free-stop function, the free-stop function is configured to operate when the opening angle of the ADF 20 is approximately 10° to 20° or more. However, when the opening angle is less than that, the moment due to the weight of the ADF 20 is set to be greater than the torque of the hinge 41 in order to hold down the document on the flatbed contact glass 13 with the ADF 20. Moreover, when the image reading unit 16 employs a contact image sensor (CIS) with a 1:1 optical system, if the force with which the ADF 20 holds down the document is weak, the document is likely to lift, and the in-plane uniformity of image density and resolution are likely to deteriorate due to the effects of illumination depth and depth of focus. Therefore, it is necessary to hold down the document with a relatively large force using the ADF 20. Consequently, if the document is placed overhanging the flatbed contact glass 13, the weight of the ADF 20 may cause the convex parts 42F and 42R to push the document into the concave parts 43F and 43R, potentially causing significant damage to the document.

[0034] One way to solve this problem is to use movable convex parts 42F and 42R that are held to move back and forth and biased in the direction of protrusion. With this method, even if the document is placed overhanging the flatbed contact glass 13, the movable convex part that is in contact with the document is pushed back by the document, preventing the document from being pushed into the concave parts 43F and 43R, and reducing the damage that may be inflicted on the document.

[0035] However, if a movable convex shape is used, in DF scanner mode, the ADF20 will remain closed even if the movable convex shape is not fitted into the concave shapes 43F and 43R when the ADF20 is closed. Therefore, if a document is transported by the ADF20 in this state, the scanned image will be skewed.

[0036] Therefore, in this embodiment, the set of convex and concave portions is divided into two sets: a set of convex portion 42F and concave portion 43F arranged on the front side of the device, and a set of convex portion 42R and concave portion 43R arranged on the rear side of the device. The convex portion 42F on the front side is a movable convex portion, while the convex portion 42R on the rear side is a fixed convex portion that cannot move forward or backward.

[0037] Figure 4(a) is a perspective view when the movable convex portion 42F is in the extended position (protruding position), and Figure 4(b) is a cross-sectional view showing the retraction mechanism of the movable convex portion 42F when it is in the extended position (protruding position). Figure 5(a) is a perspective view of the movable convex portion 42F when it is in the retracted position (non-protruding position), and Figure 5(b) is a cross-sectional view showing the retraction mechanism of the movable convex portion 42F when it is in the retracted position (non-protruding position).

[0038] The movable convex portion 42F is made of a separate component from the frame 38B of the ADF 20. The movable convex portion 42F consists of a stepped pin 44a, a compression spring 44b, a guide member 44c, and an E-type retaining ring 44d, which are arranged to protrude from the frame 38B.

[0039] The tip of the stepped pin 44a has an R-shaped or C-shaped surface formed on it, making it easier to fit into the recessed portion 43F of the scanner unit 4 even if the tip of the stepped pin 44a is slightly misaligned (see Figure 7). The compression spring 44b is attached to the stepped portion of the stepped pin 44a (the constricted portion with a smaller diameter than the tip of the stepped pin 44a) and is interposed between the frame 38B of the ADF 20 and the tip of the stepped pin 44a. As a result, the stepped pin 44a is biased in the advancing direction (protruding direction) by the biasing force of the compression spring 44b.

[0040] Furthermore, the guide member 44c slidably supports the rear end portion of the stepped pin 44a in order to maintain the posture of the stepped pin 44a. The guide member 44c may be integrated with the frame 38B or it may be a separate component. In the case of a separate component, it is preferable to fix it to the frame 38B using screws or the like. The E-shaped retaining ring 44d is a stopper member attached to the rear end portion of the stepped pin 44a and is configured to catch on the guide member 44c to prevent the stepped pin 44a from coming off in the protruding direction.

[0041] Figure 6(a) is a perspective view showing the concave portions 43F and 43R into which the convex portions 42F and 42R fit, and Figure 6(b) is a cross-sectional view of the concave portions 43F and 43R. The recessed portions 43F and 43R are slightly larger in dimension than the tip of the stepped pin 44a. In this embodiment, since the tip of the stepped pin 44a is substantially cylindrical, it is preferable to make the recessed portion a round hole, or an elongated hole that is elongated in the front-to-back direction of the device. Furthermore, chamfers are provided on the opening edges of the recessed portions 43F and 43R, making it easier for the tip of the stepped pin 44a to fit into the recessed portion 43F of the scanner unit 4 even if it is slightly misaligned (see Figure 7).

[0042] Furthermore, as shown in Figures 8(a) and (b), a configuration in which a projection-shaped portion 45 is provided around the recessed portion 43R into which the fixed convex portion 42R fits may be provided. In this case, it is preferable to provide a chamfered surface on the projection-shaped portion 45. This ensures that even if the fixed convex portion 42R is slightly misaligned from the position of the recessed portion 43R, it is guided by the chamfered surface of the projection-shaped portion 45 and fits into the recessed portion 43R, resulting in proper alignment.

[0043] On the other hand, if the fixed convex portion 42R is displaced from the position of the concave portion 43R and cannot enter the concave portion 43R, as shown in Figure 9, the fixed convex portion 42R will abut against and ride up onto the protruding portion 45. As a result, when the fixed convex portion 42R does not fit into the concave portion 43R even when the ADF 20 is closed, that is, when the alignment between the ADF 20 and the scanner unit 4 is not performed correctly even when the ADF 20 is closed, the opening angle of the ADF 20 at this time will be larger compared to a configuration without the protruding portion 45. This makes it easier for the user to recognize that the ADF 20 is not completely closed, which encourages the user to perform the ADF 20 closing operation again to achieve proper alignment, and thus suppresses the occurrence of skewed images.

[0044] According to the configuration of this embodiment, when the ADF 20 is closed, the fixed convex portion 42R fits into the concave portion 43R, thereby performing a preliminary alignment between the ADF 20 and the scanner unit 4. This preliminary alignment allows the movable convex portion 42F to move toward the concave portion 43F without deviating from its position. Then, as the movable convex portion 42F fits into the concave portion 43F, the convex portions 42F and 42R fit into the concave portions 43F and 43R respectively, completing the final positioning at these two points. This final positioning enables high-precision alignment between the ADF 20 and the scanner unit 4, suppressing the generation of skewed images in DF scanner mode.

[0045] Furthermore, in this embodiment, since one of the two convex shapes is a movable convex shape 42F, even if the document protrudes into the area where the movable convex shape 42F and the concave shape 43F fit together, the damage that may be inflicted on the document is reduced.

[0046] In particular, in this embodiment, the movable convex portion is not the rear convex portion 42R located on the pivot axis side, i.e., the rear side of the device, when the ADF 20 opens and closes, but rather the front convex portion 42F located on the outer circumference side of the rotational movement when the ADF 20 opens and closes, i.e., the front side of the device. Since the document is more likely to protrude from the front convex portion 42F than from the rear convex portion 42R, the damage that may be inflicted on the document can be reduced more effectively.

[0047] Furthermore, in this embodiment, the front-side convex portion 42F, located near the end of the ADF 20 opposite to the pivot axis, is a movable convex portion. Because the front-side convex portion 42F is positioned in this way, it is easily touched by the user's hand, and when the ADF 20 is closed, the convex portion 42F may come into contact with the user's hand, causing discomfort. In this regard, by making the front-side convex portion 42F a movable convex portion as in this embodiment, even if the convex portion 42F comes into contact with the user's hand when the ADF 20 is closed, the impact of the contact is mitigated by the action of the compression spring 44b, thereby reducing the discomfort caused to the user.

[0048] Furthermore, in this embodiment, the rear convex portion 42R, which is located closer to the pivot axis of the ADF 20 than the movable convex portion 42F, is designated as a fixed convex portion. As a result, when closing the ADF 20, the fixed convex portion 42R can reach and fit into the concave portion 43R before the movable convex portion 42F reaches the concave portion 43F. Therefore, when the movable convex portion 42F fits into the concave portion 43F, the temporary positioning by the fixed convex portion 42R and the concave portion 43R is completed, thus preventing the situation in which the movable convex portion 42F comes off the concave portion 43F and is unable to fit, thus preventing the completion of final positioning.

[0049] Furthermore, since the rear convex portion 42R is usually not touched by the user's hands, even if this rear convex portion 42R is a fixed convex portion, there will be no problem of causing discomfort to the user. The fixed convex portion 42R may be integrated with the frame 38B of the ADF20, for example, or it may be a separate component attached to the frame 38B.

[0050] In this embodiment, the convex portions 42F and 42R are provided on the ADF 20 side and the concave portions 43F and 43R are provided on the scanner unit 4 side, but it is also possible for the convex portions 42F and 42R to be provided on the scanner unit 4 side and the concave portions 43F and 43R to be provided on the ADF 20 side. However, if the convex portions 42F and 42R are provided on the scanner unit 4 side, the presence of protruding portions due to the convex portions 42F and 42R on the upper surface of the scanner unit 4 impairs the flatness of the upper surface of the scanner unit 4, so the configuration of this embodiment is preferable.

[0051] Furthermore, in this embodiment, the locations where the movable convex portion 42F and the fixed convex portion 42R fit into the concave portions 43F and 43R are located on both outer sides in the document width direction of the image reading unit 16 (on both outer sides in the document width direction of the DF contact glass 14) when in DF scanner mode (document transport reading mode). By positioning the image reading unit 16 close to the reading position in this way, the accuracy of alignment is improved so that the document transport direction by the ADF 20 does not become oblique to the reading line L of the image reading unit 16. Therefore, the generation of skewed images can be suppressed with greater accuracy.

[0052] Furthermore, in this embodiment, when closing the ADF 20, the movable convex portion 42F and the fixed convex portion 42R may not fit into the concave portions 43F and 43R, and the alignment between the ADF 20 and the scanner portion 4 may not be performed correctly. For this reason, a detection means may be provided to detect whether this alignment is performed correctly.

[0053] By providing such detection means, if alignment is not performed correctly, the system can control whether to allow the execution of DF scanner mode (transport document reading mode) or send a message to the user prompting them to perform alignment. Such corrective actions prevent situations where skewed images occur due to image reading in DF scanner mode without proper alignment.

[0054] As the detection means, for example, a means for detecting the forward and backward movement of the stepped pin 44a of the movable convex-shaped portion 42F may be used. In this case, it can be determined that alignment is not performed correctly when the stepped pin 44a is in the retracted position.

[0055] Furthermore, as the detection means, for example, an open / close sensor of the ADF 20 may be used. In this case, it can be determined that alignment is not performed correctly when the ADF 20 is not closed. In particular, when using the open / close sensor of the ADF 20 as the detection means, it is preferable to adopt the configuration illustrated in Figures 8(a) and (b) and Figure 9, that is, a configuration in which a protruding portion 45 is provided around the recessed portion 43R into which the fixed convex portion 42R fits. In this case, even if the ADF 20 is closed, the opening angle of the ADF 20 becomes larger when the fixed convex portion 42R does not fit into the recessed portion 43R and normal alignment is not performed, so the open / close sensor of the ADF 20 can detect with greater accuracy that the ADF 20 is not closed.

[0056] In this embodiment, an image reading device of the so-called one-pass double-sided simultaneous reading type (where the front side of the document is read by the image reading unit 16 of the scanner unit 4, and the back side of the document is read by the back side image reading module 35 (second image reading unit) of the ADF 20) has been described, but the device is not limited to this. For example, it may be a single-sided reading type image reading device in which only one side of the document is read by the image reading unit 16 of the scanner unit 4. It may also be a double-sided reading type image reading device in which the ADF 20 does not have an image reading unit (where the front side of the document is read by the image reading unit 16 of the scanner unit 4, and then the document is inverted and transported and read again by the image reading unit 16).

[0057] The above is just one example; each of the following embodiments produces its own unique effects. [First aspect] The first embodiment is an image reading device 5 that reads a document transported by an automatic document feeder (e.g., ADF 20) using an image reading unit 16 of an image reading device body (e.g., scanner unit 4) to which the automatic document feeder is mounted so as to be openable and closable by a rotational movement, and has alignment means for aligning the automatic document feeder and the image reading device body by having convex-shaped parts 42F, 42R provided on one of the automatic document feeder and the image reading device body fit into concave-shaped parts 43F, 43R provided on the other when the automatic document feeder is closed, wherein the alignment means comprises at least two sets of the convex-shaped parts and the concave-shaped parts, and the at least two sets of convex-shaped parts include a movable convex-shaped part 42F that is held to move back and forth and biased in the protruding direction, and a fixed convex-shaped part 42R that cannot move back and forth. In configurations where the automatic document feeder is attached to the image reader body in a way that allows it to open and close via a rotational movement, there is generally a certain amount of play, which can cause misalignment between the automatic document feeder and the image reader body when the automatic document feeder is closed. When this misalignment occurs, the direction in which the document is transported by the automatic document feeder deviates from the predetermined transport direction on the image reader body, and the document is transported at an angle to the image reading section of the image reader body. This results in a skewed image, where the scanned image is tilted. To suppress the occurrence of skew images, some conventional image readers employ an alignment mechanism in which, when the automatic document feeder is closed, two convex parts on one of the automatic document feeder and the image reader body fit into two concave parts on the other, thereby aligning the automatic document feeder and the image reader body. While this type of image reader can suppress the occurrence of skew images, there is a problem in that when scanning a document placed on the image reader body, if the document protrudes beyond the area where the convex and concave parts fit together, the convex parts will come into contact with the document and damage it. One way to solve this problem is to use a movable convex portion as the convex portion, which is held to move back and forth and biased in the direction of protrusion. With this method, even if the document is placed over the area where the movable convex portion and the concave portion fit together, the movable convex portion that comes into contact with the document will be pushed back by the document, thereby reducing the damage that may be inflicted on the document. However, if all convex parts are movable, the automatic document feeder will remain closed even if the movable convex part is not engaged with the concave part. As a result, the document may be transported and scanned by the automatic document feeder in this state, potentially causing skewed images. Therefore, in this embodiment, in at least two sets of convex and concave shapes, some sets of convex shapes employ movable convex shapes that are held to move back and forth and biased in the protruding direction, while the other sets of convex shapes employ fixed convex shapes that cannot move back and forth. As a result, when the automatic document feeder is closed, the fixed convex shape fits into the concave shape, performing a preliminary alignment between the automatic document feeder and the image reading device body, and preventing the movable convex shape from coming out of the concave shape. Furthermore, the movable convex shape also fits into the concave shape, so that at least two convex shapes fit into the concave shapes, and the final positioning is achieved. Moreover, since some of the convex shapes in the at least two sets employ movable convex shapes, compared to a configuration where the convex shape in that set is also a fixed convex shape, the damage to the document that extends beyond the area of ​​the convex shape can be reduced. Therefore, according to this embodiment, the movable convex shape can reduce the damage that may be inflicted on the original document, and the automatic document feeder can be prevented from closing when the movable convex shape is not fitted into the concave shape, thereby suppressing the occurrence of skewed images.

[0058] [Second aspect] The second embodiment is characterized in that, in the first embodiment, the fixed convex portion is positioned closer to the pivot axis of the automatic document feeder than the movable convex portion. According to this, when closing the automatic document feeder, the fixed convex part can reach and fit into the concave part before the movable convex part reaches it. Therefore, when the movable convex part fits into the concave part, the temporary positioning by the fixed convex part and the concave part is completed, thus preventing the situation in which the movable convex part comes out of the concave part and is unable to fit, thus preventing the completion of final positioning.

[0059] [Third aspect] The third embodiment is characterized in that, in the first or second embodiment, the movable convex portion is located near the end opposite to the pivot axis of the automatic document feeder. The convex portion located near the end opposite the pivot axis of the automatic document feeder is easily touched by the user's hand, and therefore can cause discomfort when the automatic document feeder is closed. In this embodiment, since this convex portion is composed of a movable convex portion, even if the movable convex portion comes into contact with the user's hand when the automatic document feeder is closed, the movable convex portion retracts, mitigating the impact of the contact and reducing the discomfort caused to the user.

[0060] [Fourth aspect] The fourth embodiment is characterized in that, in any of the first to third embodiments, the movable convex portion and the fixed convex portion are provided on the automatic document feeder side. According to this, it is not necessary to provide a protruding part on the image reading device body, thus preserving the flatness of the image reading device body.

[0061] [Fifth aspect] The fifth embodiment is characterized in that, in any of the first to fourth embodiments, the locations where the movable convex portion and the fixed convex portion fit into the concave portion are located on both outer sides in the document width direction of the image reading portion. According to this, the automatic document feeder and the main body of the image reader can be aligned near the reading position of the image reader, thus improving the accuracy of alignment to prevent the document transport direction by the automatic document feeder from being oblique to the image reader. Therefore, the generation of skewed images can be suppressed with greater precision.

[0062] [Sixth aspect] The sixth aspect is characterized in that, in any of the first to fifth aspects, the alignment means comprises only two sets of the convex-shaped portion and the concave-shaped portion. According to this, while ensuring alignment accuracy, it is less likely that the convex part will not fit into the concave part, resulting in a situation where proper alignment is not achieved.

[0063] [Seventh aspect] The seventh embodiment is characterized in that, in any of the first to sixth embodiments, it has a detection means for detecting whether the alignment by the alignment means is performed correctly. According to this, even if the alignment between the automatic document feeder and the image reading device is not performed correctly, it becomes possible to execute corrective processing to address the situation. Therefore, even if the alignment between the automatic document feeder and the image reading device is not performed correctly, the situation in which image reading is performed without proper alignment and skewed images are produced is suppressed.

[0064] [8th aspect] The eighth aspect is characterized in that, in any of the first to seventh aspects, a projection-shaped portion is provided around the recessed portion into which the fixed convex-shaped portion is fitted. According to this, even when the automatic document feeder is closed, if the fixed convex part is unable to move out of the position of the concave part and enter the concave part, that is, if the alignment between the automatic document feeder and the image reader body is not performed correctly, the fixed convex part will abut against the protruding part and ride up. As a result, the opening angle when the automatic document feeder is closed becomes larger compared to a configuration without a protruding part, making it easier for the user to recognize that the automatic document feeder is not completely closed. Consequently, the user is prompted to perform the operation of closing the automatic document feeder again to ensure proper alignment, and the occurrence of skewed images is suppressed.

[0065] [Ninth aspect] The ninth aspect is an image forming apparatus 1 equipped with an image reading device 5, characterized in that the image reading device is one of the image reading devices of the first to eighth aspects. According to this, it is possible to provide an image forming apparatus that can reduce damage to the original document by employing a movable convex shape, and can also suppress the occurrence of skewed images by preventing the automatic document feeder from closing when the movable convex shape is not fitted into the concave shape. [Explanation of Symbols]

[0066] 1: Image forming apparatus 4: Scanner section 5: Image reading device 13: Flatbed Contact Glasses 14: DF Contact Glass 15: Image forming unit 16: Image reading unit 20: ADF 38B: Frame 41: Hinge 42F: Front-side convex shape (movable convex shape) 42R: Rear convex shape (fixed convex shape) 43F: Recessed section on the front side 43R: Recessed section on the rear side 44a: Stepped pin 44b: Compression spring 44c: Guide member 44d: E-type retaining ring 45:Protrusion shape part L: Reading line [Prior art documents] [Patent Documents]

[0067] [Patent Document 1] Japanese Patent Publication No. 2022-68985

Claims

1. An image reading device that reads a document transported by an automatic document feeder using an image reading section of an image reading device body to which the automatic document feeder is mounted so as to be openable and closable by a rotational movement, The automatic document feeder has alignment means that, when the automatic document feeder is closed, a convex portion provided on one of the automatic document feeder and the image reading device body fits into a concave portion provided on the other, thereby aligning the automatic document feeder and the image reading device body. The alignment means comprises at least two sets of the convex portion and the concave portion, The image reading device is characterized in that the at least two sets of convex portions include a movable convex portion that is held to move back and forth and biased in the protruding direction, and a fixed convex portion that cannot move back and forth.

2. In the image reading device according to claim 1, The image reading device is characterized in that the fixed convex portion is positioned closer to the rotation axis of the automatic document feeder than the movable convex portion.

3. In the image reading device according to claim 1 or 2, The image reading device is characterized in that the movable convex portion is located near the end opposite to the pivot axis of the automatic document feeder.

4. In the image reading device according to claim 1 or 2, The image reading device is characterized in that the movable convex portion and the fixed convex portion are provided on the automatic document feeder side.

5. In the image reading device according to claim 1 or 2, The image reading device is characterized in that the locations where the movable convex portion and the fixed convex portion fit into the concave portion are located on both outer sides in the document width direction of the image reading portion.

6. In the image reading device according to claim 1 or 2, The image reading device is characterized in that the alignment means comprises only two sets of the convex-shaped portion and the concave-shaped portion.

7. In the image reading device according to claim 1 or 2, An image reading device characterized by having a detection means for detecting whether the alignment by the alignment means is performed correctly.

8. In the image reading device according to claim 1 or 2, An image reading device characterized by having a protruding portion around a recessed portion into which the fixed convex portion is fitted.

9. An image forming apparatus equipped with an image reading device, An image forming apparatus characterized in that the image reading device described in claim 1 or 2 is used as the image reading device.

Images