JP2009153086A - Image reading device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reading device that achieves an improved image reading quality by preventing leakage of light incident from the outside to an image reading portion or the light emitted from a light source thereof. <P>SOLUTION: In the image reading device 1 having the reading portion (50) on an upper surface of which sheets of platen glass (511) and (521) are disposed and a platen cover (53) for covering the sheets of the platen glass in a free opening/closing manner, a sheet member (58) for holding an original on the sheets of the platen glass is bonded to a lower side (531) of the platen cover. Further, a portion (587) which is not bonded to the lower side of the platen cover is included in an end portion of the sheet member, so that the portion not bonded thereto is hung down when opening and closing the platen cover. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is employed in a facsimile machine, a copying machine, or a multifunction machine in which these and a printer function are combined, and includes an image reading unit having a platen glass on an upper surface and a platen cover that covers the platen glass so as to be freely opened and closed. The present invention relates to an image reading apparatus.

In general, in the above-described image reading apparatus such as a facsimile machine, a copying machine, or a printer (including these multi-function machines), the original set on the original tray is separated one by one and continuously supplied to the reading unit, and the discharge tray And an automatic document feeder (ADF) for discharging. As a method for reading document image information, there is a method in which a reading unit is arranged in the middle of a document conveyance path of an automatic document feeder to read a document while conveying it. There is also a flatbed scanner (FBS) system in which a reading optical system composed of a light source, a mirror, a lens and the like scans while moving the lower surface of a document placed on a platen glass. Widely adopted.
A sheet member that holds down the original is provided on the lower surface side of the platen cover that covers the upper surface of the platen glass so that it can be opened and closed. The sheet member prevents reading of external light to the image reading unit, thereby reading image quality. We are trying to improve.

  In Patent Document 1 below, a document pressure plate (platen cover) is provided with a light-shielding member that is in close contact with the periphery of the contact glass (platen glass) in a state where the document is pressed by the document pressing plate. It is disclosed. As the light shielding member, a brush-like elastic body having a bristle length longer than the thickness of the document pressing plate is used. According to this, since the periphery of the contact glass on which the document is placed is covered with the light shielding member, light for irradiating the document from between the document pressing plate and the contact glass can be prevented from leaking to the outside. .

  Japanese Patent Application Laid-Open No. 2004-228620 discloses a document presser that uses a hard plastic board, which is flexible and has a document surface that is adhesive to the reading unit. According to this, since the original can be pressed uniformly, the adhesion of the original to the image reading unit is improved, and the effect of improving the reading accuracy or the deviation of the original reading position does not occur.

Japanese Patent Application Laid-Open No. H10-228688 discloses a document in which a placement surface facing member (platen cover), which is an upper lid of a document placement table, is provided with a light shielding wall that surrounds a part or the entire circumference of the placement surface. . According to this, it is supposed that light for irradiating the document can be prevented from leaking outside from a small space formed between the document placing table and the placing surface facing member.
Japanese Utility Model Publication No. 2-132235 Japanese Utility Model Publication No. 3-29937 JP 2006-186836 A

  Here, the image reading apparatus provided with the above-described automatic document feeder has the following problems. The platen cover is provided on the upper surface of the platen glass and is configured to be freely opened and closed by a pair of hinge portions with a built-in spring. The platen cover can be maintained in an open state at a predetermined angle by a mechanism of the hinge portions. It is like that. However, if an automatic document feeder is provided on one side of the upper surface of the platen cover, the balance of the platen cover is deteriorated due to the weight of the automatic document feeder main body, and the automatic document feeder is provided when the platen cover is closed. It was pointed out that the side that was not lifted. As described above, when one side of the platen cover is lifted and a gap is generated between the platen glass and the platen cover, external light may enter and black spots may be generated in the read document image information. In addition, the printed image may become dark. In particular, when the automatic document feeder is a device having a function of reading both sides of a document (RADF), since components for reading both sides are added, the weight becomes larger than the ADF for reading one side, and the platen The lift or inclination of one side of the cover becomes even more pronounced.

  Therefore, in order to deal with such problems, conventionally, the spring pressure of the hinge part configured on the side where the automatic document feeder is provided is set to be stronger than the spring pressure of the other hinge part, and one side part of the platen cover is set. The balance has been adjusted so that it will not lift up. However, when a pair of hinge portions having different spring pressures is configured, the difference in spring pressure is not apparent from the outside, and there is a risk of assembly errors of the hinge portions. In order to cope with this, it is possible to color-code the components of the hinge part or to distinguish the difference in spring pressure by making the springs built in the hinge part visible, but in this case the parts The problem is that the management becomes complicated and the cost is high.

  In addition, external light may enter between the platen glass and the platen cover, causing image defects. The platen cover is a molded product made of a synthetic resin material, and may be caused by warping of the platen cover itself. . That is, if the platen cover is warped, a gap is formed between the platen glass and external light enters from there, and light emitted from the light source of the image reading unit leaks to the outside.

In the above-described Patent Document 1 and Patent Document 3, since the light shielding member or the light shielding wall is configured with a certain constant thickness, it is possible to solve the above-described problem caused by the rising or warping of the platen cover. It was impossible.
Further, the one described in Patent Document 2 is not configured to have an automatic document feeder on its upper surface because a flexible material is used as the document presser. Therefore, this also cannot solve the problem caused by the above-described floating or warping of the platen cover.

  The present invention has been made in view of the above circumstances, and prevents an external light incident on the image reading unit or a light emitted from a light source of the image reading unit from leaking to the outside, thereby improving the read image quality. An object is to provide a reader.

An image reading apparatus according to the present invention includes an image reading unit having a platen glass on an upper surface and a platen cover that covers the platen glass so that the platen glass can be opened and closed. A sheet member that holds the document placed on the platen glass is affixed, and an end portion of the sheet member includes a portion that is not affixed to the lower surface side of the platen cover, and opens and closes the platen cover In some cases, the unattached portion hangs down.
In the present invention, an upper surface of the platen cover includes a document tray, an automatic document feeder connected to the document tray, and a discharge tray. The automatic document feeder includes a side portion of the platen cover. The end portion of the sheet member provided on the side and not provided with the automatic document feeder can be the unattached portion. Further, the platen cover can be opened and closed by a pair of hinge portions, and both the hinge portions can be made of members having a common specification.

In the image reading apparatus of the present invention, the end portion of the sheet member attached to the lower surface side of the platen cover includes a portion that is not attached to the lower surface side of the platen cover, and is attached when the platen cover is opened and closed. The part that does not hang down. As a result, even if a gap occurs between the platen glass and the platen cover due to the warping of the platen cover itself, the gap is blocked by the end of the sheet member that hangs down, and light from the outside is incident on the image reading unit. The incident can be prevented. Accordingly, it is possible to solve the problem that the read original image information includes black dots or the printed image becomes dark, and the read image quality can be improved.
Further, it is possible to prevent the light for irradiating the document from leaking outside in the image reading unit configured by the optical system. Therefore, since the light does not leak even when the luminance of the light for irradiating the document is high, the user does not feel dazzling light when reading the document and can be used comfortably.

  In the present invention, the automatic document feeder is provided on one side of the platen cover, and the end portion of the sheet member on the side not provided with the automatic document feeder can be a portion not attached. In this case, even if the other side of the platen cover is lifted by the weight of the automatic document feeder and tilted to the side equipped with the automatic document feeder, a gap is created between the platen glass and the platen cover. An unattached sheet member can hang down to close the gap. Since the gap can be closed with such a simple configuration, there is no concern about cost increase. In particular, even when the above-described RADF having a large weight is provided as an automatic document feeder, the gap can be closed by the sheet member hanging down, and the read image quality can be improved.

  Further, if the platen cover is configured to be freely opened and closed by a pair of hinge portions, and if both hinge portions are made of a member having a common specification, there is no need to use hinge portions having different spring pressures as in the prior art, and the hinge portion. There is no risk of incorrect assembly. In addition, since it is not necessary to take measures to prevent the assembly of the hinge portion, there is no concern about cost increase, and common members can be mass-produced, so that the cost can be reduced. Moreover, since a common member can be used as a hinge part, the management man-hour of components can also be reduced.

  The best mode for carrying out the present invention will be described below with reference to the drawings. 1 is a perspective view showing an example of an image forming apparatus employing the image reading apparatus of the present invention, FIG. 2 is a schematic enlarged cross-sectional view of the image forming apparatus, and FIG. 3 is a lower surface side of a platen cover of the image reading apparatus. FIG. 4 is a schematic view of the image reading apparatus showing the open / closed state of the platen cover. FIG. 5 is a plan view of a sheet member showing a modification of the sheet member attached to the lower surface side of the platen cover of the image reading apparatus.

FIG. 1 shows an image forming apparatus 1 employing an image reading apparatus 5 of the present invention, which is a so-called multi-function machine having a facsimile function, a copying function, and a printer function. The image reading apparatus 5 of the present invention is also applied to a dedicated machine such as a copying machine, a scanner, or a facsimile machine.
In the figure, an apparatus main body 10 of an image forming apparatus 1 includes a paper supply unit 2 for recording paper (paper), an electrophotographic image recording unit 3, a discharge unit 4 for recording paper after image recording, and the present invention. The image reading device 5 is configured to be stacked in the height direction in this order. An operation unit 7 is configured on the upper part of the apparatus main body 10, and the operation unit 7 includes operation buttons, a liquid crystal display screen, and the like. Used to change or confirm

The recording paper supply unit 2 includes a recording paper (paper) supply cassette 21 that can be inserted into and removed from the apparatus main body 10. As shown in FIG. 2, the recording paper supply cassette 21 includes a main body case 20 that accommodates a large number of recording papers 6 in a stacked state. A separation roller (supply roller) 22 is provided at the front end of the main body case 20. A separation pad 23 that elastically contacts the peripheral surface of the separate roller 22 is provided. Further, a recording paper (paper) push-up plate 24 that pushes up the accumulated recording paper 6 and a compression coil spring 25 that applies upward elasticity to the push-up plate 24 are installed in the main body case 20. Since the recording paper push-up plate 24 is always given upward elasticity by the compression coil spring 25, the front end portion of the recording paper 6 deposited on the push-up plate 24 is pressed against the peripheral surface of the separation roller 22. It is done. Therefore, when the separation roller 22 rotates, the stacked recording paper 6 is separated one by one from the uppermost layer portion by the cooperative action of the separation roller 22 and the separation pad 23, and enters the recording paper conveyance path 9 described later. Is paid out.
A front panel 201 having a handle portion 202 is attached to the front side of the main body case 20, and the recording paper supply cassette 21 can be inserted and removed from the front side of the image reading apparatus 1 by operating the handle portion 202.

  The image recording unit 3 includes a process unit in which a plus (or minus) charger 31, an exposure unit 32, a developing device 33, a transfer roller 34, and a cleaning device 35 are arranged in this order around the photosensitive drum 30. And a fixing device 36 on the downstream side. The photosensitive drum 30, the charger 31 and the cleaning device 35 are unitized as a drum unit, and the developing device 33 is unitized as a developing device unit. Both units are individually or coupled to the apparatus main body 10. Removably mounted. Since these units are consumables, they can be inserted into and removed from the apparatus main body 10. As a mode that can be inserted / removed, in addition to the case where it can be inserted / removed in the direction perpendicular to the paper surface in FIG. 2, it can be taken out above the apparatus body 10, or can be inserted / removed from the other side of the apparatus body 10. Sometimes it is said. The recording paper supply cassette 21 can be inserted and removed in the direction perpendicular to the paper surface in FIG.

  A registration roller pair 8 is installed in the vicinity of the upstream side of the process unit, and the recording paper 6 separated and fed out from the recording paper supply cassette 21 one by one by the action of the separation roller 22 and the separation pad 23 is It is registered by the registration roller pair 8 and introduced into the nip portion between the photosensitive drum 30 and the transfer roller 34. The surface of the photosensitive drum 30 is uniformly positively charged (or negatively charged) by the charger 31 while rotating in the direction of the arrow in FIG. 2, and an optical image based on the image information is generated by the exposure unit 32 by the photosensitive drum 30. The electrostatic latent image is formed on the surface of the photosensitive drum 30. This electrostatic latent image is formed by the difference in potential generated between the light irradiated portion and the non-irradiated portion based on the characteristics of the photoconductor on the surface of the photosensitive drum 30.

  The electrostatic latent image is successively developed by the developing device 33 to become a toner image. This toner image reaches the nip portion with the transfer roller 34 as the photosensitive drum 30 rotates. The registration roller pair 8 is rotationally driven under registration control so that the recording paper 6 is introduced into the nip portion in synchronization with the movement of the toner image on the surface of the photosensitive drum 30. The transfer roller 34 nips and conveys the recording paper 6 while being in contact with the photoconductive drum 30 and being rotationally driven in the direction of the arrow (with the photoconductive drum 30). During this time, the toner image on the surface of the photoconductive drum 30 is recorded. It is transferred to paper. The recording paper 6 onto which the toner image has been transferred is introduced into the fixing device 36 and fixed as a permanent image, and is then discharged onto the discharge tray 42 by drawing the main conveyance pass line 61 by the discharge roller pair 41. This series of conveyance of the recording paper 6 rises in a substantially vertical (vertical) state immediately after feeding out from the recording paper supply cassette 21, and in the discharge unit 4, the feeding direction from the recording paper supply cassette 21 is about 180 degrees. It is made along a recording paper conveyance path (hereinafter referred to as a main conveyance path) 9 that turns, and with such a layout configuration, the entire apparatus can be made compact.

The developing device 33 is a developing device using a two-component developer, and includes a developer storage chamber for storing a developer composed of toner and a carrier inside a resin-molded casing. In the storage chamber, two agitating and conveying screws 331, a supply roller 332, and a developing roller 333 to which a bias is applied are provided. These mechanism portions 331, 332, and 333 in the storage chamber are connected to a drive transmission mechanism (not shown) in the apparatus main body 10 when the developing device 33 is attached to a predetermined part in the apparatus main body 10, and can be rotated. State. The developing roller 333 is electrically connected to a bias application power source (not shown). A toner tank 334 and a toner hopper 335 are installed at positions separated from the developer storage chamber. When the toner concentration in the developer storage chamber decreases, the toner is developed from the toner hopper 335 via a screw conveyor (pipe screw) 336. It is replenished in the medicine reservoir. The toner tank 334 is integrated with the waste toner tank 337 and is configured as a toner cartridge 330 that is detachably attached to the apparatus main body 10. The transfer residual toner removed from the surface of the photosensitive drum 30 by the cleaning device 35 is collected in a waste toner tank 337 via a screw 338.
The developing device 33 is not limited to a system using a two-component developer, but a one-component system or other systems can also be used.

  A first switching gate 11 is installed in the main conveyance path 9 on the downstream side of the fixing device 36, and switching between the recording paper discharge side and the switchback side for double-sided recording is possible. In the drawing, a solid line switching gate 11 is set on the switchback portion side, and a two-dot chain line switching gate 11 is set on the discharge side so that the recording paper 6 can be guided. The switchback-side main transport path 9 for duplex recording joins a reverse paper transport path (hereinafter referred to as a reverse transport path) 12 via a second switching gate 121. The recording paper 6 guided to the switchback portion side by the first switching gate 11 pushes up the second switching gate 121 and is conveyed by the switchback roller pair 122. When the rear end of the recording paper 6 reaches the switchback roller pair 122, the switchback roller pair 122 temporarily stops with the rear end of the recording paper 6 being nipped. At this time, the front side of the recording paper 6 is held on the temporary tray 123. Thereafter, the switchback roller pair 122 is reversed, and the recording paper 6 is supplied to the reverse conveyance path 12. The reverse conveyance path 12 is configured to circulate to the main conveyance path 9 on the upstream side of the registration roller pair 8 from the attachment position of the second switching gate 121 of the main conveyance path 9. Two pairs of conveying rollers 124 and 125 are provided along the same. The recording paper 6 that has been recorded on one side and is conveyed along the main conveyance path 9 is introduced into the switchback unit, and then supplied to the reverse conveyance path 12 by the reverse rotation of the switchback roller pair 122. The recording paper 6 supplied to the reverse conveyance path 12 is continuously conveyed along the reverse conveyance path 12 by the conveyance roller pairs 124 and 125, joins the main conveyance path 9 along the reverse conveyance path line 62, and registration rollers It reaches pair 8. Thereafter, the toner is introduced again into the nip portion between the photosensitive drum 30 and the transfer roller 34, and recording on the back surface is performed. The recording paper 6 recorded on both sides is discharged to the discharge section 4 along the main transport path 9 as described above.

  A manual feed tray 130 is provided on the side surface of the apparatus body 10 so as to be freely opened and closed. The recording paper 6 set on the manual feed tray 130 is separated one by one by the action of the separation roller 131 and the separation pad 132 and is supplied into the apparatus main body 10. These constitute the manual paper supply unit 13. The separated and supplied recording paper 6 passes through the manual paper conveyance path 14, draws a manual conveyance path line 63 and joins the main conveyance path 9, and the nip between the photosensitive drum 30 and the transfer roller 34 by the registration roller pair 8. Introduced into the department. Accordingly, recording based on the image information is performed on the manual sheet 6 in the same manner as described above. In the image reading apparatus 1 shown in the figure, an option cassette (not shown) as a multi-stage cassette system can be installed under the recording paper supply cassette 21, and recording from the lower option cassette is performed in the apparatus main body 10. A paper conveyance path 9 'is formed. This conveyance path 9 'constitutes a part of the main conveyance path 9 when the multistage cassette system is adopted.

  An exhaust heat duct 37 of the fixing device 36 is provided below the exhaust tray 42, and an exhaust fan 38 is installed at an exhaust port of the exhaust heat duct 37. Is the discharge tray 42. The image reading device 5 is installed above the exhaust heat duct 37.

The image reading device 5 is used for copying a document image or transmitting a facsimile. The image reading device 5 includes an image reading scanning unit 50 (image reading unit) including an ADF (automatic document feeder) reading unit 51 and an FBS unit (flat bed scanner unit) 52, and is opened and closed on the image reading scanning unit 50. The platen cover 53 that is freely installed and serves as a document pressing plate is provided. The image reading / scanning unit 50 is configured by a casing, and the operation unit 7 is formed on one side (front side) of the casing of the image reading / scanning unit 50.
In the image reading / scanning unit 50, a scanning carriage 54 on which a light source 541, a plurality of mirrors 542,..., A condenser lens 543 and a CCD 544 are mounted is installed, and the scanning carriage 54 can be reciprocated by the FBS unit 52. The ADF reading unit 51 performs movement control so as to be in a fixed state. On the upper surface of the platen cover 53, an ADF original document tray 55, an ADF 56, and an ADF original discharge tray 57 are provided.

The ADF 56 is configured as a document feeder for reading a single-sided image and outputting it as a digital signal while conveying a sheet of document 59 one by one. A document tray 55 is detachably attached to the document supply port 551 of the ADF 56 so that the document tray 55 is inclined downward toward the document supply port 551. A pickup roller 561 is provided on the document supply port 551 to feed out the document deposited on the document tray 55 from the upper layer portion. Subsequent to the pickup roller 561, a separating unit including a separation roller 562 and a separation pad 563 for separating and transporting the fed originals one by one is provided. The separation pad 563 is provided with a compression spring 564 in order to be in elastic contact with the periphery of the separation roller 562.
The document 59 fed out by the pickup roller 561 is conveyed between the separation roller 562 and the separation pad 563, and is separated one by one due to the difference in the coefficient of friction with respect to the two papers as the separation roller 562 rotates, to the downstream side. It is conveyed. The documents 59 separated one by one by the separating means are transported by transport rollers sequentially provided along a document transport path 591 formed in a U-turn shape, and discharged to a discharge tray 57 (see FIG. 2).

The upper surface of the image reading scanning unit 50 is made of platen glass, and platen glasses 511 and 521 are provided in the ADF reading unit 51 and the FBS unit 52, respectively.
In the image reading / scanning section 50, the light source 541, the plurality of mirrors 542,..., The condenser lens 543, and the CCD 544 are mounted as described above, and the unitized scanning carriage 54 is installed. Irradiation light emitted from the light source 541 is reflected by being reflected by the originals on the platen glasses 511 and 521, and then repeatedly reflected by a plurality of mirrors 542, condensed by a condensing lens 543, and incident on the CCD 544 (FIG. 2, one-dot chain line) See the light path). In the CCD 544, image information drawn on the surface of the document is converted into an electrical signal and output as a digital signal.
The example shown in the figure shows an example of two mirrors 542, but the present invention is not limited to this.

The scanning carriage 54 moves immediately below the platen glass 511 in order to read the document passing over the platen glass 511 when reading the ADF document. Then, when the document 59 passes over the platen glass 511, the image information on the surface of the document is read by the scanning carriage 54 waiting under the platen glass 511.
The scanning carriage 54 moves in the FBS unit 52 in order to read the document 59 placed on the platen glass 521 when reading the FBS document. Then, it reciprocates along the lower surface of the platen glass 521, and image information on the surface of the document 59 is read by the scanning carriage 54 during this reciprocation.

As shown in FIG. 1, the platen cover 53 is provided so as to freely open and close the platen glasses 511 and 521, and is configured to open and close with a handle portion 532. The platen cover 53 and the apparatus main body 10 (the housing of the image reading scanning unit 50) are connected by a pair of hinge units 60.
The pair of hinge portions 60 are composed of members having a common specification, and are inserted into a mounting hole 500 formed on the housing of the image reading scanning portion 50 so as to be movable up and down and supported, and a platen cover 53. And a swing member 602 fixed to the side by screws. The hinge portion 60 is swingably supported by a swing shaft 601 so that the platen cover 53 can be opened and closed. A spring (not shown) is built in the support member 603, and a combination of the elasticity of the spring provided on the support member 603 and the cam mechanism provided on the swing member 602 acts, thereby causing a platen cover. 53 can be lifted up or kept open at a predetermined angle.

  The pair of hinge portions 60 used here are not limited to those made of members having common specifications as described above, and those made of different members or those having different spring pressures can be used. However, even if the platen cover 53 is warped or lifted when the platen cover 53 is closed due to the weight of the ADF 56, the platen glass is caused by a portion (non-margin area 587) where the sheet member 58 is not attached as will be described later. A gap 589 (see FIG. 4) with respect to 521 can be closed. Therefore, the hinge member 60 which consists of a common member as mentioned above can be used, and according to this, it becomes unnecessary to use the hinge part from which spring pressure differs like the past, and there exists a possibility that the assembly | attachment mistake of a hinge part may arise. Disappears. In addition, since it is not necessary to take measures to prevent the assembly of the hinge part, there is no concern about cost increase, and common members can be mass-produced, so that the cost can be reduced. Furthermore, since a common member can be used as the hinge part 60, the man-hours for managing parts can be reduced.

Next, the sheet member 58 attached to the lower surface 531 side of the platen cover 53 will be described in detail.
A sheet member 58 is attached to the lower surface 531 side of the platen cover 53 to hold the document placed on the platen glass 521 when the FBS unit 52 reads. In FIG. 1, the cross-hatched portion shown in the sheet member 58 shows marginal regions 581 and 582 attached to the lower surface 531 side of the platen cover 53, and in this example, the side of the side provided with the ADF 56. Two locations on the side that is not provided with the end portion are marginal regions.
FIG. 3 shows a cross-sectional view of the sheet member 58.
The sheet member 58 has a two-layer structure of a thin sheet layer 583 made of a resin material such as polypropylene (PP) and a sponge layer 584 made of a soft foamed resin material such as urethane foam. The surface of the sheet layer 583 is white, and the thickness thereof is 0.5 mm to 1.0 mm, and the thickness of the sponge layer 584 is 3.0 mm to 4.0 mm.

The marginal region 581 at the end of the sheet member 58 on the ADF 56 side does not constitute the sponge layer 584, and a magic tape (registered trademark) 585 is pasted on the sheet layer 583 via a double-sided tape (not shown). . The end portion of the sheet member 58 on the side not provided with the ADF 56 is not a margin region, and a margin region 582 is formed with a predetermined width (for example, 60 mm to 80 mm). That is, the end portion of the sheet member 58 on the side not provided with the ADF 56 includes the above-described non-margin area 587 having a predetermined width.
Reference numeral 586 denotes a double-sided tape. One side of a double-sided tape 586 having a width of about 50 mm is attached to the surface of the sponge layer 584, and the opposite side is attached to the lower surface 531 side of the platen cover 53. An adhesive surface (not shown) corresponding to Velcro (registered trademark) 585 is formed at a predetermined position on the lower surface 531 side of the platen cover 53, and the end of the sheet member 58 on the ADF 56 side can be attached and detached. ing. Therefore, the one side end portion of the sheet member 58 is peeled off to allow maintenance of the parts formed on the lower surface of the platen cover 53.
On the other hand, the end of the sheet member 58 on the side not provided with the ADF 56 has a non-margin area 587, and therefore, when the platen cover 53 is opened and closed, the non-margin area 587 (attached to the lower surface 531 side of the platen cover 53). The part that is not) hangs down.

FIG. 4 is a diagram schematically showing the image reading device 5, and shows an open / closed state of the platen cover 53. 4 shows the case where the platen cover 53 is open, and the image reading device 5 shown below in the direction of the arrow in FIG. 4 shows the case where the platen cover 53 is closed. ing. In the drawing, the configuration of the hinge portion 60 and the like are omitted for explanation.
As shown in the drawing, when the platen cover 53 is changed from the open state to the closed state, the sheet member 58 in the non-margin area 587 is not attached to the lower surface 531 side of the platen cover 53, so Become. Therefore, when the platen cover 53 is completely closed, even if one side of the platen cover 53 (the side not provided with the ADF 56) is lifted by the weight of the ADF 56, the sheet member 58 in the non-margin area 587 hangs down. A gap 589 between the platen glass 521 and the platen cover 53 can be closed.

As described above, even if the gap 589 is formed between the platen glass 521 and the platen cover 53, the gap 589 is closed by the end of the sheet member 58 that hangs down, and light from the outside enters the image reading scanning unit 50. Can be prevented. Therefore, it is possible to solve the problem that the read original image information includes black dots or the printed image becomes dark, and the read image quality can be improved.
Further, since the gap 589 can be closed by the hanging of the non-margin area 587 of the sheet member 58 in this way, it is possible to prevent light from the light source 541 for irradiating the document from leaking to the outside. Therefore, since light does not leak even when the luminance of the light source 541 is high, the user does not feel dazzling light when reading a document and can be used comfortably. Further, the sheet member 58 that has been conventionally used can be used as the sheet member 58. Until now, the both end portions of the sheet member 58 have been used as the marginal area, but it is only necessary to provide the non-margin area 587 as described above. So there is no concern about cost increase.

FIG. 5 is a view showing a modified example of the marginal region of the sheet member 58 attached to the lower surface 531 side of the platen cover 53. A two-dot chain line indicates the platen cover 53, and reference numeral 533 in the drawing indicates an opening through which the document 59 read by the ADF reading unit 51 passes.
This modification differs in that the non-margin area is provided not only on the side not provided with the ADF 56 but also on the side not provided with the hinge part 60. Others are the same as in the above example, and the description is omitted.
As shown in the drawing, if the side not provided with the hinge portion 60 is defined as a non-margin area 588, when the platen cover 53 is closed, a hanging portion of the sheet member 58 is formed on the operation portion 7 side.
According to this, regardless of the weight of the ADF 56, even if the platen cover 53 itself is warped, the gap 589 between the platen glass 521 and the platen glass 521 can be closed by the hung sheet member 58. Accordingly, it is possible to prevent external light from entering the image reading / scanning unit 50 or light emitted from the light source 541 of the image reading / scanning unit 50 from leaking to the outside, thereby further improving the read image quality.

The configuration of the sheet member 58, the layer structure, the widths of the marginal areas 581 and 582, the width of the non-marginal area 587, and the like are not limited to the above examples. For example, the sheet layer 583 and the sponge layer 584 may have the same size, and the end portion on the ADF 56 side may be attached to the lower surface 531 side of the platen cover 53 with a double-sided tape.
Further, the opening / closing mechanism of the platen cover 53 or the mechanism of the hinge portion 60 is not limited to the illustrated example. For example, the present invention can be applied to a structure in which the hinge portion 60 is configured at the end portion on the ADF 56 side so that the platen cover 53 can be opened and closed in the lateral direction.

1 is a perspective view illustrating an example of an image forming apparatus in which an image reading apparatus of the present invention is employed. 2 is a schematic enlarged cross-sectional view of the image forming apparatus. FIG. It is sectional drawing of the sheet | seat member affixed on the lower surface side of the platen cover of the image reading apparatus. FIG. 2 is a schematic diagram of the image reading apparatus, showing an open / close state of a platen cover. It is a top view of the sheet member which shows the modification of the sheet member affixed on the lower surface side of the platen cover of the image reading apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 5 Image reading apparatus 50 Image reading scanning part 53 Platen cover 55 Document tray 56 ADF (automatic document feeder)
57 Discharge tray 60 Hinge

Claims (3)

An image reading apparatus including an image reading unit including a platen glass on an upper surface, and a platen cover that covers the platen glass so as to be freely opened and closed.
A sheet member that holds the document placed on the platen glass is attached to the lower surface side of the platen cover,
An end portion of the sheet member includes a portion that is not attached to the lower surface side of the platen cover, and the portion that is not attached hangs down when the platen cover is opened and closed. . The image reading apparatus according to claim 1,
On the upper surface of the platen cover, a document tray, an automatic document feeder connected to the document tray, and a discharge tray are provided, and the automatic document feeder is provided on one side of the platen cover,
An image reading apparatus characterized in that an end portion of a sheet member on a side not provided with the automatic document feeder is an unattached portion. The image reading apparatus according to claim 1 or 2,
The platen cover is configured to be openable and closable by a pair of hinge portions, and both hinge portions are made of members having a common specification.

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