JP2014003396A - Image reading device and image formation device incorporating the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reading device which, while restraining increase in parts count and the worsening of assembly work, can restrain the wear of resin members and the vibration of a scanner unit.SOLUTION: An image reading device 6 comprises a hand placement document glass 25b, an automatic read glass 25a, a resin member 61, a scanner unit 62 including a CIS sensor 62a which reads images from the document, and an enclosure 64. At the top face 62b of the scanner unit 62, a slide member 67 is provided. When the scanner unit 62 reciprocates between beneath the hand placement document glass 25b and beneath the automatic read glass 25a, the slide member 67 slides along the sliding face of a bridge section 64e formed in the enclosure 64 as an integral body with it.

Description

  The present invention relates to an image reading apparatus and an image forming apparatus including the same, and in particular, two glass plates, and a scanner unit provided so as to be reciprocally movable below the two glass plates along the sub-scanning direction. And an image reading apparatus in which a scanner unit is urged toward a glass plate, and an image forming apparatus including the image reading apparatus.

  2. Description of the Related Art Conventionally, in an image reading apparatus mounted on a multifunction machine or the like using an electrophotographic process, a sheet-like document is sequentially fed to a document placing table (glass plate) and discharged from the document placing table after the reading is completed. Some of them are equipped with such an automatic document feeder. In such an image reading apparatus, a sheet-through method in which a document is automatically conveyed and read by a document conveying device while the document press is closed, and a document on the document placement table is opened by opening and closing the document press for each reading. Two types of reading methods are possible: a document fixing method in which a document is read by replacing the sheets one by one and moving the scanner unit. In the former sheet-through method, the scanner unit in the image reading apparatus scans and moves the document while being held at a predetermined image reading position, while in the latter document fixing method, A reading operation is performed while the scanner unit scans and moves.

  FIG. 13 is a cross-sectional view showing an example of a conventional image reading apparatus capable of two types of reading methods, a sheet through method and a document fixing method. As shown in FIG. 13, an example of a conventional image reading apparatus is a manually placed original glass (first glass plate) 101a on which an original is placed and an automatic reading glass (second glass) through which an automatically conveyed original passes. Plate) 101b made of contact glass 101, resin member 102 provided between two glass plates (manually placed original glass 101a and automatic reading glass 101b), and contact glass 101 are arranged below the original. A scanner unit 103 having a reading sensor 103a for reading the image of the image, and holding the scanner unit 103, and reciprocally moved below the two glass plates along the sub-scanning direction (arrows A and B directions). A carriage 104, a scanner unit 103, and a frame 105 for housing the carriage 104 are provided.

  The resin member 102 is provided with an upper protruding portion 102a that protrudes upward from the upper surface of the automatic reading glass 101b. The upper projecting portion 102a has an inclined surface for guiding the document that is automatically conveyed and passed up. The resin member 102 is provided with a lower protruding portion 102b that protrudes below the automatic reading glass 101b. The lower protrusion 102 b prevents paper dust and dust from dropping on the scanner unit 103 from the gap between the automatic reading glass 101 b and the resin member 102.

  By the way, as a scanner unit image reading method, a CCD sensor method using a charge coupled device (reading sensor) called a CCD (Charge Coupled Devices) sensor and a photoelectric conversion element (reading sensor) called a CMOS (Complementary MOS) sensor are used. There is a CIS sensor system used.

  The CCD sensor method is easy to focus even on a document with a large depth of field, so even a book or uneven document is not in close contact with the contact glass. ) Has the advantage of high speed. On the other hand, there is a demerit that the structure of the scanner unit on which the CCD sensor is mounted is complicated and large, and the cost is high.

  On the other hand, the CIS sensor method does not require a mirror required in the CCD sensor method, and thus has a merit that the scanner unit on which the CIS sensor is mounted can be made thin, and the structure is simple, so that the cost is low. On the other hand, since the CIS sensor has a very small depth of field and narrower than the CCD sensor, it has a demerit that it cannot read a book document or an uneven document uniformly. For this reason, in the CIS sensor system, it is necessary to maintain the distance from the document with high accuracy due to the narrow depth of field.

  Therefore, in the conventional image reading apparatus shown in FIG. 13, the CIS sensor type scanner unit 103 is brought into close contact with the lower surface of the contact glass 101. Specifically, a spring 106 that biases the scanner unit 103 upward is provided, and a sliding member 107 that slides in contact with the contact glass 101 is provided on the upper surface of the scanner unit 103. As a result, the distance between the scanner unit 103 and the document is kept constant.

  However, in the conventional image reading apparatus, when the scanner unit 103 reciprocates below the manual placement glass 101a and below the automatic reading glass 101b along the sub-scanning direction, the manual placement glass 101a and the resin Due to the step between the member 102 and the automatic reading glass 101b, the sliding member 107 and the resin member 102 may be worn, or the scanner unit 103 may vibrate and adversely affect the reading of the original image.

  Therefore, for example, in Patent Document 1, a guide member having a lower surface that is arranged from below the contact glass (glass for manual placement) to below the flow reading glass (automatic reading glass) and protrudes downward in a mountain shape. And an image reading apparatus in which a roller (rotating member) that rolls while contacting the lower surface of the guide member is provided in a contact image sensor (scanner unit).

  In this image reading apparatus, when the contact image sensor reciprocates below the two glass plates along the sub-scanning direction, the roller (rotating member) rolls while being in contact with the lower surface of the guide member. The mold image sensor moves away from the glass plate. As a result, the contact image sensor and the spacer (sliding member) provided on the contact image sensor and the stay (resin member) do not come into contact with each other. Can be prevented from being worn. Moreover, since the guide member is provided from the lower side of the contact glass to the lower side of the flow-reading glass, the inclination angle of the lower surface of the guide member can be made gentle. Thereby, it can suppress that a contact type image sensor vibrates when reciprocating below the two glass plates.

JP 2006-115031 A

  However, when a guide member and a roller (rotating member) are separately provided as in Patent Document 1, there are problems that the number of parts increases and the assembling workability of the apparatus deteriorates.

  In order to suppress an increase in the number of parts, it is conceivable to provide the guide member integrally with the stay (resin member). In this case, the stay sandwiches the contact glass (hand-placed original glass) from above and below. Therefore, there is a problem that the assembling workability of the apparatus is particularly deteriorated.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to prevent resin member wear and scanner unit vibration while suppressing increase in the number of parts and deterioration in assembly workability. And an image forming apparatus including the image reading apparatus.

  In order to achieve the above object, an image reading apparatus of the present invention includes a first glass plate on which a document is placed, a second glass plate through which an automatically conveyed document passes, a first glass plate, and a second glass. A scanner unit including a resin member disposed between the plates, a reciprocally movable lower side of the first glass plate and a lower side of the second glass plate along the sub-scanning direction, and having a reading sensor for reading an image of the document, and a scanner A carriage that holds the unit; a biasing member that is provided on the carriage and biases the scanner unit upward; and a frame that houses the scanner unit, the carriage, and the biasing member, and is in the sub-scanning direction on the upper surface of the scanner unit On both sides in the main scanning direction orthogonal to the bottom, there are provided sliding members that slide in contact with the lower surface of the first glass plate and the lower surface of the second glass plate. The frame is integrally formed with a bridging portion that is disposed from the lower side of the first glass plate to the lower side of the second glass plate and has a sliding surface that protrudes downward in a mountain shape. When reciprocating below the first glass plate and below the second glass plate, the sliding member slides while contacting the sliding surface of the bridging portion.

  In this image reading apparatus, as described above, the upper surface of the scanner unit is provided with the sliding members that slide in contact with the lower surface of the first glass plate and the lower surface of the second glass plate, A bridging portion having a sliding surface protruding downward in a mountain shape is formed, and when the scanner unit reciprocates below the first glass plate and below the second glass plate, the sliding member Slide while contacting the sliding surface of the bridge. Thereby, since the sliding member is separated from the first glass plate and the second glass plate by sliding while contacting the sliding surface of the bridging portion, each of the first glass plate, the resin member and the second glass plate It can suppress that a scanner unit and a sliding member contact the level | step difference between members. For this reason, damage to the scanner unit and wear of the resin member can be suppressed.

  Further, as described above, by providing the bridging portion from below the first glass plate to below the second glass plate, the inclination angle of the sliding surface of the bridging portion can be moderated. Thereby, it can suppress that a scanner unit vibrates when reciprocating below the two glass plates.

  Further, as described above, the bridge portion is integrally formed on the frame, and the sliding member slides while contacting the sliding surface of the bridge portion. Thereby, compared with the case where a bridge part and the member which passes the sliding surface of a bridge part are provided separately, while being able to reduce a number of parts, the assembly workability | operativity of an apparatus can be improved. That is, as compared with the case where a guide member and a roller (rotating member) are separately provided as in Patent Document 1, the number of parts can be reduced and the assembly workability of the apparatus can be improved.

  In the image reading apparatus, preferably, the resin member is provided with a protruding portion that protrudes downward from the lower surface of the second glass plate, and the sliding surface of the bridging portion protrudes when viewed from the main scanning direction. It is arranged at the same height as the lower surface of the part or below the lower surface of the protruding part. If comprised in this way, it can suppress easily that a scanner unit contacts the protrusion part of a resin member.

  In the image reading apparatus, preferably, the resin member is provided with a protruding portion that protrudes downward from the lower surface of the second glass plate, and the sliding member is located on both outer sides in the main scanning direction with respect to the protruding portion. Is provided. If comprised in this way, while being able to prevent a sliding member contacting a protrusion part easily, a bridge | crosslinking part can be easily provided integrally with a flame | frame.

  In the image reading apparatus, preferably, the upper surface of the scanner unit is formed in a rectangular shape, and the sliding members are provided at at least four corner portions of the upper surface of the scanner unit. If comprised in this way, before a scanner unit contacts a bridge | crosslinking part, a sliding member can be made to contact a bridge | crosslinking part reliably. Further, the stability of the scanner unit when the sliding member is pressed against the glass plate can be improved as compared with the case where the sliding member is provided only at the center of, for example, two short sides on the upper surface of the scanner unit. Thereby, the vibration of the scanner unit can be further suppressed.

  In this case, preferably, the upper surface of the scanner unit includes two short sides extending in the sub-scanning direction and two long sides orthogonal to the short side, and the sliding member extends along the two short sides. Is formed. If comprised in this way, even if the protrusion height of a sliding member is made small, it can prevent reliably that the center part of the subscanning direction of the upper surface of a scanner unit contacts a bridge | crosslinking part and a resin member. As a result, the protruding height of the sliding member can be made smaller, and the distance between the scanner unit and the document can be made smaller.

  The image forming apparatus of the present invention includes the image reading apparatus having the above-described configuration. If comprised in this way, the image forming apparatus which can suppress the abrasion of a resin member and the vibration of a scanner unit can be obtained, suppressing the increase in a number of parts, and the deterioration of assembly workability | operativity.

  As described above, according to the present invention, an image reading apparatus capable of suppressing wear of a resin member and vibration of a scanner unit while suppressing an increase in the number of parts and a deterioration in assembling workability are provided. An image forming apparatus can be easily obtained.

1 is a cross-sectional view schematically showing a structure of an image forming apparatus including an image reading apparatus according to an embodiment of the present invention. 1 is a cross-sectional view illustrating a structure of a document conveying device of an image forming apparatus according to an embodiment of the present invention. 1 is a perspective view illustrating a structure of an image reading apparatus according to an embodiment of the present invention. 1 is a perspective view illustrating a structure in which an upper frame of an image reading apparatus according to an embodiment of the present invention is removed. It is sectional drawing which showed the structure around the scanner unit and resin member of one Embodiment of this invention. It is the perspective view which showed the structure of the periphery of the resin member and bridge | crosslinking part of one Embodiment of this invention from the downward direction. It is the top view which showed the structure of the scanner unit of one Embodiment of this invention. It is sectional drawing which showed the structure around the scanner unit and resin member of one Embodiment of this invention. It is sectional drawing which showed the structure around the scanner unit and resin member of one Embodiment of this invention. It is sectional drawing which showed the structure around the scanner unit and resin member of one Embodiment of this invention. It is a top view for demonstrating the structure of the sliding member of the modification of this invention. It is sectional drawing which showed the structure of the periphery of the scanner unit provided with the sliding member shown in FIG. 11, and the resin member. It is a sectional view showing an example of a conventional image reading apparatus capable of two types of reading methods, a sheet through method and a document fixing method.

  Embodiments of the present invention will be described below with reference to the drawings.

  A structure of an image forming apparatus 100 including an image reading device 6 according to an embodiment of the present invention will be described with reference to FIGS. In FIG. 1, in the image forming apparatus 100 (here, a digital multi-function peripheral is shown as an example), when performing a copying operation, image data of a document is read and converted into an image signal by an image reading apparatus 6 described later. On the other hand, in the image forming unit 3 in the MFP main body 2, the photosensitive drum 5 rotating in the clockwise direction in the drawing is uniformly charged by the charging unit 4, and is based on the original image data read by the image reading device 6. An electrostatic latent image is formed on the photosensitive drum 5 by a laser beam from an exposure unit (laser scanning unit or the like) 7, and a developer (hereinafter referred to as toner) is attached to the electrostatic latent image by the developing unit 8. An image is formed. The toner is supplied to the developing unit 8 from the toner container 9.

  A sheet is conveyed from the sheet feeding mechanism 10 to the image forming unit 3 via the sheet conveying path 11 and the registration roller pair 12 toward the photosensitive drum 5 on which the toner image is formed as described above. 3, the toner image on the surface of the photosensitive drum 5 is transferred onto the sheet by the transfer roller 13 (image transfer unit). The sheet onto which the toner image has been transferred is separated from the photosensitive drum 5 and conveyed to a fixing unit 14 having a fixing roller pair 14a to fix the toner image. The paper that has passed through the fixing unit 14 is sent to a paper conveyance path 15 that branches in a plurality of directions, and is fed by a path switching mechanism 21, 22 having a plurality of path switching guides provided at branch points of the paper conveyance path 15. The conveyance direction is sorted, and the first discharge tray 17a and the second discharge tray 17b are formed via the discharge roller pair 20a or the discharge roller pair 20b as it is (or after being sent to the paper conveyance path 16 and copied on both sides). It is discharged to the paper discharge unit.

  Although not shown, a static elimination device that removes residual charges on the surface of the photosensitive drum 5 is provided on the downstream side of the cleaning device 18. Further, the paper feed mechanism 10 is detachably attached to the multifunction machine main body 2 and includes a plurality of paper feed cassettes 10a and 10b for storing paper, and a stack bypass (manual feed tray) 10c provided above the paper feed cassettes 10a and 10b. These are connected to the image forming unit 3 including the photosensitive drum 5 and the developing unit 8 by the paper transport path 11.

  An image reading device 6 is disposed on the upper part of the multifunction device main body 2. A document placed on the contact glass 25 (see FIG. 3) of the image reading device 6 is pressed onto the upper surface of the multifunction device main body 2. A holding platen (document pressing) 24 is provided so as to be openable and closable, and a document conveying device 27 for automatically conveying the document to the image reading device 6 is attached on the platen 24.

  Specifically, the sheet conveyance path 15 is first branched into left and right forks on the downstream side of the fixing roller pair 14a, and one path (the path branched in the right direction in FIG. 1) communicates with the first discharge tray 17a. It is configured as follows. The other path (the path that branches in the left direction in FIG. 1) branches into two branches via the conveying roller pair 19, and the other path (the path that branches in the left direction in FIG. 1) is the second discharge tray 17b. It is comprised so that it may communicate with. On the other hand, the other path (the path that branches downward in FIG. 1) is configured to communicate with the sheet conveyance path 16.

  As shown in FIG. 2, a document transport path d from the document feed tray 29 to the document discharge tray 32 is formed in the cover member 31 of the document transport device 27, and a pickup roller is provided along the document transport path d. 33, a document conveying member including a sheet feeding belt 34 and a separation roller 35, a registration roller pair 36, a conveyance roller pair 37, 38, 39, and 40, a CIS roller 41, a reverse roller pair 42, a discharge roller pair 43, and the like is provided. ing.

  The sheet feeding belt 34 is wound around a driving roller 44a and a driven roller 44b, and a separation roller 35 is in contact with the roller at a predetermined pressure from below. The separation roller 35 has a built-in torque limiter, which rotates in the opposite direction to the paper feeding belt 34 only when the rotational load is lower than a predetermined torque, and is driven to rotate with the paper feeding belt 34 when the rotational load exceeds a predetermined torque. It is supposed to be. Above the pickup roller 33, an upper surface detection sensor 50 for detecting the upper surface position of the document is disposed.

  The contact glass 25 includes an automatic reading glass (second glass plate) 25a and a manually placed original glass (first glass plate) 25b, and is arranged to face the automatic reading glass 25a and is used as a white reference for shading correction. There are provided a plate and a document pressing portion (none of which is shown) on the white reference plate for pressing the white reference plate against the automatic reading glass 25a. The document conveyance path d is curved so as to be reversed between the registration roller pair 36 and the automatic reading glass 25a. In addition, a plurality of paper detection sensors including a paper feed sensor S1 and a discharge sensor S2 for detecting whether or not a document is present is provided in a proper position on the document conveyance path d.

  Next, a sheet-through type document conveying operation using the document conveying device 27 will be described. In the sheet-through method, after a plurality of documents are set on the document feed tray 29 with the image surface facing upward, when the copy start button on the operation panel 55 (see FIG. 1) of the image forming apparatus 100 is turned on, A lift plate 45 lifted by an elevating mechanism (not shown) pushes up the pickup roller 33 through the document, and the weight of a frame (not shown) including the pickup roller 33 is added to the lift plate 45, thereby The upper surface is pressed against the pickup roller 33 with a predetermined pressure (paper feeding pressure).

  Here, the pickup roller 33, the driving roller 44a, the driven roller 44b, and the paper feed belt 34 are arranged in a frame body (not shown). The pickup roller 33 is connected to a driving roller 44a by a gear (not shown). When the driving roller 44a is rotated by a roller driving motor (not shown), the pickup roller 33 is stretched by the driving roller 44a and the driven roller 44b. The paper belt 34 is driven to rotate, and the pickup roller 33 is also driven to rotate.

  The document set on the document feed tray 29 is usually fed by the pickup roller 33 to the nip portion between the feed belt 34 and the separation roller 35 as a plurality of upper sheets. Then, only the uppermost one of the plurality of documents is separated by the separation roller 35 and conveyed toward the registration roller pair 36. At that time, after the leading edge of the document is detected by the sheet feeding sensor S1, the document is conveyed by a predetermined distance, and then the rotation of the pickup roller 33 and the sheet feeding belt 34 is stopped by stopping the operation of the roller driving motor. Paper feeding ends. The document that has been primarily fed is stopped in a state where the leading end of the document is bent at the nip portion of the registration roller pair 36.

  Secondary feeding is started after a predetermined time has elapsed since the completion of primary feeding. That is, the registration roller pair 36 is rotationally driven by the operation of a secondary paper feed drive motor (not shown). The document is conveyed by the registration roller pair 36, the conveyance roller pairs 37 to 39, and the CIS roller 41 through the automatic reading glass 25a toward the discharge roller pair 43, and finally is discharged by the discharge roller pair 43. It is discharged onto the tray 32. At that time, the completion of image reading of one document is detected by detecting the passage of the trailing edge of the document by the discharge sensor S2.

  Here, the discharge sensor S2 has a count function for counting the number of documents every time the document conveyance is completed. If the paper feed sensor S1 detects a subsequent document, the second and subsequent document conveyance is performed as described above. Will continue as well. When the original passes through the automatic reading glass 25a, the image of the original is read by the image reading device 6 (see FIG. 1) through the automatic reading glass 25a from above by contacting the conveyance guide 53. It has become.

  When reading a double-sided original, a one-step reading method in which an image on the back side of the original is read by a contact image sensor 51 provided facing the CIS roller 41, and an image on the front side of the original is read by an automatic reading glass 25a. After the image on the surface of the document is read by the reading glass 25a, the document is distributed to the reversing tray 30 by the branching claws 47a, 47b, and 47c, the reversing roller pair 42 is reversed, and the back surface of the document is turned up again. There is a two-stage reading method in which the image is conveyed to the upstream side of the registration roller pair 36 and the image on the back side of the document is read by the automatic reading glass 25a.

  Reading by the contact image sensor 51 can shorten the reading time, but is inferior in image quality as compared with reading by the automatic reading glass 25a. For this reason, a one-step reading method using the contact image sensor 51 is used for text originals, and a two-step reading method using the reverse tray 30 is used when high-quality and high-definition reading is required for photo originals. It is preferable.

  When the two-stage reading method is used, when the original after reading is sequentially discharged to the original discharge tray 32 as it is, the discharged original is stacked with the reverse side of the state set on the original feed tray 29. It will be. Therefore, after the image on the back side of the document is read by the automatic reading glass 25a, the branching claws 47a to 47c are swung to introduce the document again onto the reversing tray 30, and through the conveying roller pair 40 and the discharge roller pair 43. The document is discharged to the document discharge tray 32. As a result, the front and back of each document are reversed again before being discharged, so that they can be stacked on the document discharge tray 32 while maintaining the state of being set on the document feed tray 29.

  Next, the configuration of the image reading device 6 for reading an image of a document as an electric signal will be described.

  As shown in FIGS. 3 to 5, the image reading device 6 includes a contact glass 25 including a manually placed original glass 25 b on which an original is placed and an automatic reading glass 25 a through which the automatically conveyed original passes over the upper surface. , A resin member 61 disposed between the manually placed original glass 25b and the automatic reading glass 25a, a scanner unit 62 for reading an image of the original, and holding the scanner unit 62, and in the sub-scanning direction (arrow A and B directions). ), And a resin housing (frame) 64 including a lower frame 64a and an upper frame 64b for housing the scanner unit 62, the carriage 63, and the like.

  As shown in FIG. 4, a guide shaft 65 that regulates the position of the carriage 63 in the main scanning direction (arrow C direction) is provided at a substantially central portion of the lower frame 64 a with respect to the main scanning direction (arrow C direction) of the scanner unit 62. The endless driving belt 66 to which the carriage 63 is fixed is disposed along the sub-scanning direction (arrow A and B directions) of the scanner unit 62. Further, rail portions 64c for slidably supporting the carriage 63 are formed at both ends in the main scanning direction of the lower frame 64a with the guide shaft 65 as the center. When driving force from a motor (not shown) such as a pulse motor is transmitted to the driving belt 66, the driving belt 66 rotates, and the scanner unit 62 together with the carriage 63 moves along the guide shaft 65 and the rail portion 64c. Reciprocate in the A and B directions.

  Edges of the lower surface of the manually placed original glass 25b, the automatic reading glass 25a, and the resin member 61 are placed on the wall 64d of the lower frame 64a. The wall portions 64d are integrally formed on both sides of the lower frame 64a in the main scanning direction. Further, the edges of the upper surfaces of the manually placed original glass 25b, the automatic reading glass 25a, and the resin member 61 are bonded to the upper frame 64b by an adhesive layer (not shown).

  The automatic reading glass 25a and the resin member 61 are formed in an elongated shape extending in the main scanning direction. As shown in FIGS. 5 and 6, the resin member 61 is provided with an upper protruding portion 61a that protrudes upward from the upper surface of the automatic reading glass 25a. The upper projecting portion 61a has an inclined surface for guiding the document that is automatically conveyed and passed up. The portion of the resin member 61 on the manually placed document glass 25b functions as an abutting reference surface of the document when placing the document by hand, and displays the document position and size.

  Further, the resin member 61 is provided with a lower protruding portion (protruding portion) 61b protruding below the automatic reading glass 25a. The lower protruding portion (protruding portion) 61 b prevents paper dust and dust from dropping on the scanner unit 62 from the gap between the automatic reading glass 25 a and the resin member 61. The lower protrusion 61b is disposed at a predetermined distance from the wall 64d and is formed to extend in the main scanning direction.

  As shown in FIG. 5, the scanner unit 62 includes a light source (not shown) and a CIS sensor (reading sensor) 62a. The light emitted from the light source is reflected by the document and received by the CIS sensor 62a. The scanner unit 62 has a home position directly below a white reference plate (not shown). The CIS sensor type scanner unit 62 is not provided with a mirror, unlike the CCD sensor type scanner unit.

  As shown in FIG. 7, the upper surface 62b of the scanner unit 62 is formed in a rectangular shape, and includes two short sides 62c extending in the sub-scanning direction and two long sides 62d orthogonal to the short side 62c. . On both sides of the upper surface 62b of the scanner unit 62 in the main scanning direction, sliding members 67 that slide in contact with the lower surface of the contact glass 25 are provided.

  In the present embodiment, the sliding member 67 is provided only at the four corners of the upper surface 62 b of the scanner unit 62. In addition, as shown in FIG. 5, the sliding member 67 has a protruding height that is slightly larger than the thickness of the lower protruding portion 61b (the amount of protrusion downward from the lower surface of the contact glass 25) and the thickness of the bridging portion 64e described later. It may be formed so as to have (a protruding amount upward from the upper surface 62b of the scanner unit 62).

  The carriage 63 is formed with a recess 63a in which the scanner unit 62 is disposed. A compression coil spring is provided between the bottom surface of the recess 63a and the lower surface of the scanner unit 62 in the vicinity of both ends in the main scanning direction of the scanner unit 62. (Biasing member) 68 is provided. The scanner unit 62 is biased upward by a compression coil spring 68, and the sliding member 67 is pressed against the lower surface of the contact glass 25. As a result, the distance between the CIS sensor type scanner unit 62 having a small depth of field and the original image surface is kept constant, so that the original image can be read uniformly.

  As shown in FIGS. 5 and 6, a bridging portion 64e having a sliding surface (lower surface) protruding downward in a mountain shape is integrally formed on the wall portion 64d of the lower frame 64a. The bridging portion 64e is formed from the lower side of the manually placed glass 25b to the lower side of the automatic reading glass 25a. Further, the bridging portion 64e and the sliding member 67 are provided on both outer sides in the arrow C direction (main scanning direction) with respect to the lower protruding portion 61b.

  As shown in FIG. 5, the sliding surface of the bridging portion 64 e is arranged at a height position substantially the same as the lower surface of the lower protruding portion 61 b or below the lower surface of the lower protruding portion 61 b when viewed from the main scanning direction. Yes. That is, when viewed from the main scanning direction, the lower protrusion 61b is accommodated in the bridging portion 64e. Further, the lowermost surface of the bridging portion 64e is disposed at substantially the same height as the lowermost surface of the lower protruding portion 61b. Note that the lowermost surface of the bridging portion 64e may be disposed above the lowermost surface of the lower protruding portion 61b as long as the upper surface 62b of the scanner unit 62 is within a range that does not contact the bridging portion 64e and the resin member 61. Good.

  In the above configuration, when an original image is read by the original fixing method, first, an original (not shown) is placed on the manually placed original glass 25b with the image surface facing downward. The scanner unit 62 is moved in the direction of arrow A at a predetermined speed from the scanner home side (left side in FIG. 5) to the scanner return side (right side in FIG. 5) while irradiating the image surface of the document with light from the light source. Let As a result, the light reflected on the image plane is imaged and imaged on the CIS sensor 62a. The imaged image light is subjected to pixel decomposition in the CIS sensor 62a, converted into an electrical signal corresponding to the density of each pixel, and an image is read.

  On the other hand, when reading a document image by the sheet-through method, the scanner unit 62 is moved to a position immediately below the image reading area (image reading position) of the automatic reading glass 25a (position in FIG. 5). Then, the image light reflected by the image surface is irradiated on the CIS sensor 62a while irradiating the image surface of the document sequentially conveyed while being lightly pressed toward the automatic reading glass 25a by the document conveying device 27. The image is read on the image.

  As described above, when the scanner unit 62 reciprocates below the automatic reading glass 25a and below the manual document glass 25b along the sub-scanning direction, the sliding member 67 slides on the sliding surface of the bridging portion 64e. Slide while touching. Specifically, when the scanner unit 62 moves in the direction of arrow B from the position below the hand-positioned original glass 25b (position in FIG. 8), the sliding member 67 on the arrow B direction side bridges as shown in FIG. It rides on the sliding surface of the part 64e, and the part on the arrow B direction side of the scanner unit 62 moves away from the contact glass 25. When the scanner unit 62 further moves in the arrow B direction, the sliding member 67 on the arrow B direction side contacts the lower surface of the contact glass 25 as shown in FIG. Then, the sliding member 67 on the arrow A direction side rides on the sliding surface of the bridging portion 64 e, and the portion on the arrow A direction side of the scanner unit 62 moves away from the contact glass 25. For this reason, the scanner unit 62 and the sliding member 67 do not contact the lower protruding portion 61 b of the resin member 61.

  In the present embodiment, as described above, the upper surface 62b of the scanner unit 62 is provided with the sliding member 67 that slides in contact with the lower surface of the manually placed glass 25b and the lower surface of the automatic reading glass 25a. The wall portion 64d of the housing 64 is formed with a bridging portion 64e having a sliding surface (lower surface) projecting downward in a mountain shape, and the scanner unit 62 is located below the hand-placed original glass 25b. When reciprocating below the automatic reading glass 25a, the sliding member 67 slides while contacting the sliding surface of the bridging portion 64e. Thus, the sliding member 67 is separated from the contact glass 25 by sliding while contacting the sliding surface of the bridging portion 64e. Therefore, each of the manually placed original glass 25b, the resin member 61, and the automatic reading glass 25a is separated. It is possible to suppress the scanner unit 62 and the sliding member 67 from coming into contact with the steps between the members. For this reason, it is possible to suppress the scanner unit 62 from being damaged and the resin member 61 from being worn.

  Further, as described above, the bridging portion 64e is provided from the lower side of the manually placed original glass 25b to the lower side of the automatic reading glass 25a, whereby the inclination angle of the sliding surface of the bridging portion 64e can be moderated. . Thereby, it is possible to prevent the scanner unit 62 from vibrating when it reciprocates below the hand-placed original glass 25b and below the automatic reading glass 25a.

  As described above, the bridge portion 64e is integrally formed with the wall portion 64d of the housing 64, and the sliding member 67 slides while contacting the sliding surface of the bridge portion 64e. Thereby, compared with the case where the bridge | bridging part 64e and the member which passes the sliding surface of the bridge | bridging part 64e are provided separately, while being able to reduce a number of parts, the assembly workability | operativity of an apparatus can be improved. That is, as compared with the case where a guide member and a roller (rotating member) are separately provided as in Patent Document 1, the number of parts can be reduced and the assembly workability of the apparatus can be improved.

  As described above, the sliding surface of the bridging portion 64e is disposed at the same height as the lower surface of the lower protruding portion 61b or below the lower surface of the lower protruding portion 61b when viewed from the main scanning direction. Yes. Thereby, it is possible to easily suppress the scanner unit 62 from coming into contact with the lower protruding portion 61 b of the resin member 61. If the lowermost surface of the bridging portion 64e is disposed more than necessary below the lowermost surface of the lower protruding portion 61b, the amount of movement of the scanner unit 62 in the vertical direction increases. In this case, the scanner unit 62 is likely to vibrate, and the characteristics of the CIS sensor 62a may be deteriorated due to an increase in the biasing force applied to the scanner unit 62. Therefore, the lowermost surface of the bridging portion 64e is a lower protruding portion. It is preferable that the height is substantially the same as the lowermost surface of 61b.

  Further, as described above, the sliding member 67 is provided on both outer sides in the main scanning direction with respect to the lower protruding portion 61b. Accordingly, the sliding member 67 can be easily prevented from coming into contact with the lower protruding portion 61b, and the bridging portion 64e can be easily provided integrally with the wall portion 64d of the lower frame 64a.

  Further, as described above, the upper surface 62 b of the scanner unit 62 is formed in a rectangular shape, and the sliding members 67 are provided at the four corners of the upper surface 62 b of the scanner unit 62. Thereby, before the scanner unit 62 contacts the bridge | crosslinking part 64e, the sliding member 67 can be made to contact the bridge | crosslinking part 64e reliably. Further, the stability of the scanner unit 62 when the sliding member 67 is pressed against the contact glass 25 as compared with the case where the sliding member 67 is provided only at the center of, for example, the two short sides 62c of the upper surface 62b of the scanner unit 62. Can be improved. Thereby, the vibration of the scanner unit 62 can be further suppressed.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the above-described embodiment, the image reading apparatus mounted on the image forming apparatus has been described as an example of the image reading apparatus of the present invention. However, the present invention can also be applied to an image scanner used separately from the image forming apparatus. It is.

  In the above embodiment, an example in which the sliding member is provided only at the four corners on the upper surface of the scanner unit has been described, but the present invention is not limited thereto. For example, as in the modification of the present invention shown in FIG. 11, the sliding member 67 may be formed so as to extend along the two short sides 62 c of the upper surface 62 b of the scanner unit 62. In this case, as shown in FIG. 12, even if the protruding height of the sliding member 67 is reduced, the center portion of the upper surface 62b of the scanner unit 62 in the sub-scanning direction contacts the bridging portion 64e and the lower protruding portion 61b. Can be surely prevented. Thereby, the protruding height of the sliding member 67 can be made smaller, and the distance between the scanner unit 62 and the document can be made smaller.

  Moreover, in the said embodiment, although shown about the example by which the lower side protrusion part which protrudes below rather than the lower surface of the glass for automatic reading was provided in the resin member, this invention is not limited to this, A lower side is provided in a resin member. The protrusion may not be provided. Also in this case, it is effective to apply the present invention because a small step is generated between each member of the manually placed glass, the resin member, and the automatic reading glass.

6 Image reader 25a Automatic reading glass (second glass plate)
25b Glass for manual placement (first glass plate)
61 Resin member 61b Lower protrusion (protrusion)
62 Scanner unit 62a CIS sensor (reading sensor)
62b Upper surface 62c Short side 62d Long side 63 Carriage 64 Housing (frame)
64e Cross-linking part 67 Sliding member 68 Compression coil spring (biasing member)
100 Image forming apparatus

Claims (6)

A first glass plate on which an original is placed;
A second glass plate through which the automatically conveyed document passes;
A resin member disposed between the first glass plate and the second glass plate;
A scanner unit that is provided so as to be capable of reciprocating below the first glass plate and below the second glass plate along a sub-scanning direction, and having a reading sensor that reads an image of the document;
A carriage for holding the scanner unit;
A biasing member provided on the carriage and biasing the scanner unit upward;
A frame that houses the scanner unit, the carriage, and the biasing member;
With
Sliding members that slide in contact with the lower surface of the first glass plate and the lower surface of the second glass plate are provided on both sides of the upper surface of the scanner unit in the main scanning direction orthogonal to the sub-scanning direction. And
The frame is integrally formed with a bridging portion having a sliding surface that is disposed from the lower side of the first glass plate to the lower side of the second glass plate and protrudes downward in a mountain shape,
When the scanner unit reciprocates below the first glass plate and below the second glass plate, the sliding member slides while contacting the sliding surface of the bridging portion. Image reading device. The resin member is provided with a protruding portion that protrudes downward from the lower surface of the second glass plate,
The sliding surface of the bridging portion is disposed at the same height as the lower surface of the projecting portion or below the lower surface of the projecting portion when viewed from the main scanning direction. The image reading apparatus described. The resin member is provided with a protruding portion that protrudes downward from the lower surface of the second glass plate,
The image reading apparatus according to claim 1, wherein the sliding member is provided on both outer sides in the main scanning direction with respect to the protruding portion. The upper surface of the scanner unit is formed in a rectangular shape,
The image reading apparatus according to claim 1, wherein the sliding member is provided at at least four corners on the upper surface of the scanner unit. The upper surface of the scanner unit includes two short sides extending in the sub-scanning direction, and two long sides orthogonal to the short side,
The image reading apparatus according to claim 4, wherein the sliding member is formed to extend along the two short sides.   An image forming apparatus comprising the image reading apparatus according to claim 1.

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