JP4834459B2 - Image reading apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to an image reading apparatus that reads an original while conveying it, and an image forming apparatus such as a copying machine, a facsimile apparatus, and a scanner apparatus to which the image reading apparatus is applied.

  As a prior art related to this type of image reading apparatus, it has a slit glass disposed in a document reading section and a reading guide member disposed at a position facing the slit glass. There is known one in which a positioning member for determining an interval is integrated with a slit glass (for example, see Patent Document 1).

According to the above prior art, since the slit glass and the positioning member are integrated, it is expected that the number of parts is reduced and the assembly cost is reduced accordingly. In the prior art, since the positioning member that has been in contact with the slit glass as a separate part is integrated with the slit glass, the positioning member does not collide with the slit glass when the document conveying unit is brought into contact with the reading unit. It has a structure. In addition, in the prior art, both ends of the reading guide member are pressed against the positioning member by a cushion member (spring). For this reason, in the prior art, since the impact when the reading guide member contacts the positioning member is reduced by the cushion member, it is expected that damage to the slit glass can be prevented.
JP-A-2005-75564 (page 2-4, FIG. 10)

  However, even if the distance between the slit glass and the reading guide member is adjusted by the positioning member as in the prior art, the structure in which both ends of the reading guide member are elastically supported by the cushion member, The reading guide member is pulled in the document transport direction by the frictional force, and its posture tends to become unstable. If the posture of the reading guide member fluctuates during the conveyance of the original, the original cannot be stably pressed against the slit glass, which causes a reading failure of the original. Possible reading defects in this case include those in which the read image becomes unclear or the image is distorted due to the document rising from the slit glass surface.

  Accordingly, an object of the present invention is to provide a technique capable of solving the problems in the prior art as described above and realizing stable document reading.

  The present invention provides an image reading unit having a reading surface for reading an original, and an original placed on the upper surface side of the image reading unit and sent to the lower surface, An image reading device that reads an image of a document by an image reading unit while transporting the document by the document transport mechanism.

  In particular, the present invention solves the above-described problem by ensuring a gap between the reading surface and the guide member by the gap securing member only on one end side of the reading surface. That is, the present invention provides a hinge mechanism that connects the document conveying mechanism to the image reading unit so that the document reading mechanism can be opened and closed up and down, and one end edge along the lower surface of the document conveying mechanism and the other end opposite thereto. A document conveying path is formed between the reading surface and the reading surface by being positioned facing the reading surface from above with the document conveying mechanism closed downward. A guide member that guides a document conveyed through the conveyance path in a state of facing the reading surface, and a reading surface at a portion corresponding to the other end edge portion of the image reading unit with the document conveying mechanism closed. A clearance securing member which is provided on the upper side and contacts the guide member from below when the document transport mechanism is closed, and secures a clearance serving as a transport path between the reading surface and the guide member in this contact state. (Claim 1).

  The gap securing member is disposed on the reading surface, and is interposed between the guide member and the reading surface in a state where the document conveying unit is closed. In this state, the gap securing member secures a gap serving as a document conveyance path between the reading surface and the guide member by supporting the guide member from below. At this time, the size of the gap is constant according to the thickness of the gap securing member, so that the document can be stably conveyed through the conveyance path formed in the gap.

  In the present invention, the document conveying mechanism is connected to the image reading unit so as to be able to open and close in the vertical direction (an operation that flips upward or conversely conversely). In this case, considering the convenience when the operator opens and closes the document conveying mechanism, the hinge mechanism for opening and closing is positioned on the rear side (the back side opposite to the near side) as viewed from the operator. If the position where the hinge mechanism is provided is one end edge of the document transport mechanism, the other end edge on the opposite side is the front side as viewed from the operator of the image reading apparatus (or image forming apparatus). Accordingly, the one end where the gap securing member is installed is the front end as viewed from the operator.

  According to the present invention, when the document transport mechanism is closed with respect to the image reading unit, one end of the guide member contacts the gap securing member and does not directly contact the reading surface. The glass material constituting the surface is not damaged.

Said guide member, when viewed in a state in which the document conveying mechanism is closed, the displacement in the vertical direction at the end corresponding to the other edge portion of the document transport mechanism that is constrained. For this reason, even if the guide member is pulled by a frictional force generated between the document and the guide member during conveyance of the document, the posture of the guide member is not likely to be unstable. Thereby, since the original can be conveyed while being reliably opposed to the reading surface, occurrence of a reading defect is reliably prevented.

The present invention is also provided at one edge of the document conveying mechanism to generate a pressing force that pushes the guide member toward the reading surface while the document conveying mechanism is closed, while the document passes through the conveying path. support mechanism that allows the guide member against the pressure to displace in a direction away from the reading surface when Ru further comprising a.

  With such a support mechanism, even if the thickness of the document to be conveyed becomes extremely large, the support mechanism allows the guide member to be displaced, so the thickness of the document and the elasticity of the document (waist) The gap of the conveyance path can be increased according to the strength of the. As a result, it is possible to reliably read a document by stably transporting documents of various thicknesses and materials.

Incidentally guide member displacement by the support mechanism at the end corresponding to the end edge of the document transport mechanism only (rear side) that is allowed. That is, a gap (conveyance path) is secured by contact with the gap securing member at the end (front side) corresponding to the other end edge of the document feeding mechanism, and the gap is restricted by restraining the displacement there. There is an advantage that it can be kept constant. In contrast, if the displacement of the guide member is constrained at both ends, it becomes difficult to cope with changes in the thickness and elastic force of the document. Therefore, here, an end portion corresponding to one edge portion of the document transport mechanism (rear side) It is preferable that the displacement is allowed only by (). As a result, it is possible to deal with various types of originals having different thicknesses and materials while ensuring a stable gap.

More practically, the gap securing member that is disposed so as to cover the area outside the conveying path on the reading surface. Since the gap securing member is interposed between the reading surface and the guide member, the optimal arrangement of the gap securing member is positioned outside the document conveyance path. On the other hand, when the reading surface is formed of a plate-shaped glass material, the glass material tends to be easily damaged such as cracks and chips at the end portions thereof. For this reason, if it is an aspect which covers the area | region of a reading surface on the outer side rather than the conveyance path of a document with the member for clearance ensuring, the edge part area | region of a glass material will be protected and the damage will be prevented effectively.

Further, according to the present invention, a plate-like glass material that forms a reading surface is provided at a position outside the conveyance path, provided in a portion corresponding to the other end edge portion of the image reading unit in a state where the document conveyance mechanism is closed. It is preferable to provide a vibration isolating material that prevents the glass material from vibrating while being supported from below. In this case, the gap securing member, that are arranged spread in a range larger than the vibration-proof material at a position outside of the transport path on the reading surface.

The background of adopting the above configuration in the present invention is as follows.
The anti-vibration material plays a role of suppressing the vibration of the glass material during transportation of the image reading apparatus or the image forming apparatus equipped with the image reading apparatus and preventing the damage. Such an anti-vibration material is also usually located outside the document conveyance path. This is because when an image is read optically by the image reading unit, a shielding object cannot be disposed below the reading surface inside the conveyance path. On the other hand, the vibration isolator is a sufficient part if it can be used for the purpose of isolating the glass material during transportation of the image reading apparatus or the image forming apparatus equipped with the image reading apparatus. There is no merit in the top.

  For this reason, it is preferable that the vibration isolator is installed as a part having a necessary and sufficient minimum size, at a position outside the conveyance path, below the glass material. On the other hand, the total length of the glass material is sufficiently longer than the range of the conveyance path, and further extends beyond the vibration isolation material to the outside of the conveyance path. Close to the holding state). When a load due to the contact of the guide member acts on the end portion of the glass material, a bending moment is likely to be generated around the vibration isolating material at the end portion of the glass material. Further, when the contact between the reading surface and the guide member is concentrated on one place, the load acts on the glass material in a concentrated manner. In this case, if no allowance is provided, the glass material may be damaged while a repeated load is applied. Therefore, in the present invention, the gap securing member is arranged at a position outside the conveyance path on the reading surface so as to extend to a range larger than that of the vibration isolating material, thereby making surface contact with the guide member in a wide range and distributing the load. By doing so, the impact and bending moment generated in the glass material are alleviated and the damage is prevented.

Clearance securing member may include a mode that is stuck on the reading surface via a double-sided adhesive tape having a non nonwoven material to the substrate layer is not preferable. Examples of the non-woven fabric material include resin materials such as acrylic.

The background of adopting the above configuration in the present invention is as follows.
First, as long as the gap securing member is fixed with the double-sided adhesive tape, the gap securing member can be cleanly separated from the reading surface when recycling the image reading apparatus or the image forming apparatus equipped with the image reading apparatus. There is an advantage that it can be easily reused.

  However, when the opening / closing operation of the document conveying mechanism is repeated over a long period of time, a load is repeatedly applied to the gap securing member due to an impact when the document conveying mechanism is closed. The direction of this load is not always vertical but often involves a force component in the horizontal direction. This is based on the fact that the opening / closing operation of the document conveying mechanism is a manual operation, and that the hinge mechanism that supports the document conveying mechanism also has play, looseness, rattling, and the like on the mechanism. In this way, while a load including a force component in the horizontal direction repeatedly acts on the gap securing member, a shearing force acts on the base material layer of the double-sided pressure-sensitive adhesive tape that fixes it, and eventually the base material layer breaks. It is assumed that this will lead to When a nonwoven fabric material is used for the base material layer of the double-sided pressure-sensitive adhesive tape, the direction and position of the gap securing member gradually change from the beginning as the breakage progresses inside the base material layer while a repeated load is applied. I know it will shift. If the position of the gap securing member is shifted, there occurs a problem that the gap securing member enters the inside of the transport path to narrow the transport path or deteriorate the appearance.

  For this reason, in the present invention, the gap securing member is fixed to the reading surface by a double-sided adhesive tape having a base layer made of a material (for example, acrylic resin) having higher shear durability due to repeated load than the nonwoven material. Accordingly, the position of the gap securing member can be stably held over a long period of time, and the document conveyance path can be held constant.

  Alternatively, if the gap securing member is attached using a double-sided adhesive tape, even if a glass plate is cracked or chipped due to an extremely excessive impact that is not assumed, It is possible to effectively prevent the fragments from scattering.

The present invention is based on the image read by using the image reading apparatus, also Ru is configured as an image forming apparatus for forming an image to be transferred to the printing paper. In this case, it is possible to read a document image stably and accurately, and use this to form an accurate image.

  According to the present invention, it is possible to provide an image reading apparatus that can accurately read an original while stably conveying the original through the conveyance path. Further, the impact at the time of opening and closing the document conveying mechanism can be mitigated and the glass material forming the reading surface can be reliably prevented from being damaged. In addition, the performance as the image reading apparatus can be secured or improved with a simple configuration at low cost.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The image reading apparatus of the present invention can be applied to an image forming apparatus such as a copying machine as an example. Hereinafter, an embodiment of an image forming apparatus to which an image reading apparatus according to the present invention is applied will be described.

  FIG. 1 is an explanatory diagram showing an outline of the image forming apparatus 10. FIG. 1 shows the front of the image forming apparatus 10, and the upper direction in the figure coincides with the upper direction of the image forming apparatus 10. A user who operates the image forming apparatus 10 is located on the front side of the image forming apparatus 10 as viewed in the figure. Accordingly, the right direction in the figure corresponds to the right direction as viewed from the user operating the image forming apparatus 10, and the left direction in the figure corresponds to the left direction as viewed from the user operating the image forming apparatus 10.

  As shown in FIG. 1, the image forming apparatus 10 is used as a copying machine. The image forming apparatus 10 includes a box-shaped apparatus main body 11 called an in-body discharge type. In addition, the image forming apparatus 10 includes an image reading unit 16 installed on the upper part of the apparatus main body 11. An optical system unit 20 for reading a document image is installed in the image reading unit 16.

  The apparatus main body 11 is equipped with an image forming unit 12 and a fixing unit 13. The image forming unit 12 has a function of forming an image based on image information of a document read by the optical system unit 20 of the image reading unit 16. The fixing unit 13 has a function of performing a fixing process on the image formed on the paper P after being formed by the image forming unit 12. In order to store the paper P, a paper storage unit 14 is installed in the lower part of the apparatus main body 11. On the other hand, a paper discharge unit 15 is installed at the top of the apparatus main body 11. The paper discharge unit 15 is formed with an in-body paper discharge tray 151 that receives the discharged paper P after the fixing process.

  The image reading unit 16 includes an exterior cover 160 that houses the optical system unit 20 including the document table glass 31 and the reading glass 32 at a position on the upper surface. Among these, the original platen glass 31 on the right side as viewed from the front of the image forming apparatus 10 (as viewed from the user who operates it) has a size on which the original P1 can be placed. The exterior cover 160 is provided with a document mat (document pressing member) 161 for pressing a document placed on the document table glass 31 so as to be freely opened and closed.

  As indicated by a two-dot chain line in FIG. 1, an automatic document feeder (auto document feeder) 200 is installed on the upper surface of the image reading unit 16, and the document feeder 200 is attached to the image reading unit 16. It is connected via a hinge mechanism (see FIGS. 3 and 4). The original mat 161 is opened and closed by the hinge mechanism together with the original conveying device 200. The other reading glass 32 is formed in a shape that is long and narrow in the front-rear direction, and is disposed adjacent to the left side of the original table glass 31. At this position, the reading glass 32 is used when reading (flow-reading) the original when the original is conveyed by the original conveying apparatus 200. The document feeder 200 will be further described later.

  The optical system unit 20 reads a document image from below through the document table glass 31 while the document placed on the document table glass 31 is pressed by the document mat 161. Alternatively, when the original is conveyed by the original conveying apparatus 200, the optical system unit 20 reads an original image that passes through the upper surface of the reading glass 32. The image information of the document read by the image reading unit 16 is output to the image forming unit 12 after being subjected to predetermined processing.

  Although omitted in FIG. 1, the exterior cover 160 is provided with an operation panel, a liquid crystal display (LCD), and the like on the front surface thereof. Of these, the operation panel is used by the user to input processing conditions relating to document reading, copying, and the like. Further, the LCD has a function of a touch panel for inputting a user's operation through a screen in addition to a function of displaying information on operations and information such as items.

  The image forming unit 12 forms a toner image on the paper supplied from the paper storage unit 14. In this embodiment, the image forming unit 12 is sequentially arranged from the upstream side (right side in FIG. 1) to the downstream side. A magenta unit 12M, a cyan unit 12C, a yellow unit 12Y, and a black unit 12K are provided. These four units 12M, 12C, 12Y, and 12K are arranged in the apparatus main body 11 at intervals in the width direction.

  Each unit 12M, 12C, 12Y, and 12K is provided with a photosensitive drum 121 and a developing device 122, respectively. Each photoconductor drum 121 receives toner supplied from the corresponding developing device 122 while rotating counterclockwise in FIG. Each developing device 122 is replenished with toner from a toner cartridge (not shown) disposed on the front side of the apparatus main body 11.

  A charger 123 is provided immediately below each photoconductor drum 121, and an exposure device 124 is provided further below each charger 123. Each photosensitive drum 121 is charged uniformly by the charger 123, and laser light corresponding to each color based on the image data read by the image reading unit 16 is charged from each exposure device 124 after being charged. By irradiating the peripheral surface of the photosensitive drum 121, an electrostatic latent image is formed on the peripheral surface of each photosensitive drum 121. A toner image is formed on the peripheral surface of each photosensitive drum 121 by supplying toner from the developing device 122 to these electrostatic latent images.

  An endless transfer belt 125 is arranged above the four photosensitive drums 121 arranged in contact with the photosensitive drums 121 from above. On both sides of the arrangement of the photoconductive drums 121, a pair of driving rollers 125a and driven rollers 125b are disposed at the upper position on the left and right sides. The transfer belt 125 extends in the arrangement direction of the photosensitive drums 121 while being wound between the driving roller 125a and the driven roller 125b.

  The transfer belt 125 is pressed against the peripheral surface of the photosensitive drum 121 by a transfer roller 125 c provided corresponding to each photosensitive drum 121. In this state, the transfer belt 125 circulates between the driving roller and the driven roller in synchronization with each photosensitive drum 121.

  Therefore, when the transfer belt 125 goes around, first, a magenta toner image is transferred from the photosensitive drum 121 of the magenta unit 12M to the surface thereof. Next, a cyan toner image is transferred in an overcoated state from the photosensitive drum 121 of the cyan unit 12C to the same position where the transfer is performed. In the same manner, a yellow toner image and finally a black toner image are transferred to the same position on the surface of the transfer belt 125 in an overcoated state. As a result, a color toner image is formed on the surface of the transfer belt 125. This color toner image is transferred onto the paper P conveyed from the paper storage unit 14.

  As shown in FIG. 1, a cleaning device 126 that removes and cleans residual toner on the peripheral surface of each photoconductive drum 121 is provided at the left position of each photoconductive drum 121. The peripheral surface of the photosensitive drum 121 cleaned by the cleaning device 126 goes to the charger 123 for a new charging process.

  Waste toner removed from the peripheral surface of the photosensitive drum 121 by the cleaning device 126 is collected in a toner collection bottle (not shown) through a predetermined path and stored there.

  In addition, a sheet conveyance path 111 extending in the vertical direction is formed at the left position of the image forming unit 12 as viewed in FIG. The paper transport path 111 is provided with a transport roller pair 112 at an appropriate position, and the paper fed from the paper storage unit 14 is transported toward the transfer belt 125 by driving the transport roller pair 112. A second transfer roller 113 is provided in the sheet conveyance path 111 in a state of being in contact with the surface of the transfer belt 125 at a position facing the driving roller 125a. When the paper P transported through the paper transport path 111 passes through a nip formed between the transfer belt 125 and the second transfer roller 113, the toner image on the transfer belt 125 is transferred.

  A cleaning device (not shown) for removing toner remaining on the surface of the transfer belt 125 is provided at the right end portion of the transfer belt 125. The transfer belt 125 that has completed the transfer process to the paper P is circulated toward the next transfer process in a state in which the residual toner on the surface thereof is removed by a cleaning device (not shown).

  The fixing unit 13 performs a fixing process on the toner image on the paper transferred by the image forming unit 12. The fixing unit 13 includes a fixing roller 131 provided with an energization heating element serving as a heating source therein, and a pressure roller 132 disposed so as to face the fixing roller 131. Then, the transfer-processed sheet P derived from the image forming unit 12 via the charger 123 passes through a nip formed between the fixing roller 131 and the pressure roller 132. At this time, the toner image is fixed on the paper P by the heat treatment heated by the fixing roller 131, and a stable color image is formed on the printing surface. The color-printed paper P is discharged from the fixing unit 13 to the in-body paper discharge tray 151 through the paper discharge conveyance path 114 extending upward.

  The paper storage unit 14 has a paper tray 141 that is detachably mounted at a position below the exposure device 124 in the apparatus main body 11. The paper tray 141 stores paper in a stacked state. Then, the paper P is fed out from the paper layer stored in the paper tray 141 one by one by the drive of the pickup roller 142, and is introduced into the image forming unit 12 through the paper conveyance path 111.

  2 and 3 are perspective views showing the upper part of the image forming apparatus 10 as viewed from the upper left front. Note that the front direction in FIG. 1 (the direction facing the operating user) coincides with the direction of the one-dot chain line (IV-IV line) in FIG. 2 or the direction of the one-dot chain line (V-V line) in FIG. . In FIG. 2, the document conveying device 200 is shown in a closed state, and in FIG. 3, the document conveying device 200 is shown in an opened state.

  As partially shown in FIG. 3, the document conveying device 200 is supported by the image reading unit 16 through hinge mechanisms 204 at two positions at the rear end. When an image forming process is actually performed by the image forming apparatus 10, the user operates various buttons, keys, and switches on the operation panel 17 with the document conveying apparatus 200 closed as shown in FIG. Is done. When the user places a document on the document table, the document conveying device 200 is opened upward as shown in FIG. In this state, the user can place the document face down on the upper surface of the larger platen glass 31. When the document is set, the document feeder 200 is closed again by the user.

  The operation panel 17 is provided with a start button for starting a document reading operation and a numeric keypad (no reference sign) for inputting the number of transferred sheets. The LCD 18 displays various comments and messages related to the image forming process.

  The document feeder 200 is provided with a document tray 202 on which a plurality of documents can be set in a stacked manner. When the user sets a document on the document tray 202 and presses the start button on the operation panel 17, the document is transported one by one by the document transport device 200 and discharged to the back side of the document tray 202. The document to be conveyed passes through the reading glass 32 in the middle thereof, and the document image is read by the image reading unit 16 (so-called flow reading).

  4 and 5 show longitudinal sections of the document conveying device 200 and the image reading unit 16. 4 and 5 are positioned in a vertical plane including a center line (IV-IV line in FIG. 2 and VV line in FIG. 3) along the longitudinal direction of the reading glass 32. Yes. The right direction in FIGS. 4 and 5 corresponds to the front direction facing the user who operates the image forming apparatus 10. As shown in FIGS. 4 and 5, the document feeder 200 is equipped with mechanism parts, driving parts, and the like for automatically feeding a document set on the document tray 202. In addition, since these components can apply a well-known thing, the description is abbreviate | omitted here.

  As shown in FIGS. 4 and 5, the document conveying device 200 is provided with a guide member 206 at a lower position thereof. When the document conveying device 200 is closed, the guide member 206 is located just above the reading glass 32. In this state, the guide member 206 is elongated along the longitudinal direction (front-rear direction) of the reading glass 32. Yes.

  FIG. 6 is a simplified vertical cross section of the document conveying device 200, the two document table glasses 31, and the reading glass 32 when the image forming apparatus 10 is viewed from the front. The cross section shown in FIG. 6 is located in the vertical plane including the center line (VI-VI line in FIG. 4) along the short side direction of the reading glass 32. When viewed in the cross-section of FIG. 6, the guide member 206 has a cross-sectional shape that is convex downward. The reason why the guide member 206 has such a cross-sectional shape is to guide the document on the lower surface thereof when the document transport apparatus 200 transports the document. That is, as indicated by the arrows in FIG. 6, when the original is conveyed by the original conveying apparatus 200, the uppermost original is sent out from the upper original tray 202 by the pickup roller 208. Subsequently, the original is conveyed by the carry-in roller 210 at the downstream position, and further conveyed between the lower surface of the guide member 206 and the upper surface of the reading glass 32 while being reversed by the large-diameter conveyance roller 212. At this time, the image surface of the original is read by the image reading unit 16. A scooping guide 213 is installed between the reading glass 32 and the document table glass 31. The document that has passed over the reading glass 32 is guided by the scooping guide 213, sent into the document transport device 200, and discharged to the document discharge unit 214 below the document tray 202.

  The guide member 206 also serves to press the document along the upper surface of the reading glass 32 when the document is transported, thereby reliably reading the document by the image reading unit 16. Since the document is conveyed between the lower surface of the guide member 206 and the upper surface of the reading glass 32, a gap for allowing the document to pass through is usually secured here. In the present embodiment, a necessary gap is secured between the lower surface of the guide member 206 and the upper surface of the reading glass 32 with the following configuration.

[Configuration of the front part]
FIG. 7 partially shows the upper surface of the image reading unit 16 as viewed from directly above. The lower part in FIG. 7 corresponds to the front direction facing the user who operates the image forming apparatus 10. In the present embodiment, the clearance securing member 220 is provided on the upper surface only at the front end of the reading glass 32. Such a clearance securing member is not provided at the rear end of the reading glass 32. The gap securing member 220 is formed by forming a resin sheet material such as polycarbonate (PC) into a square shape, and is attached to the upper surface of the reading glass 32 using a double-sided adhesive tape. Moreover, in this embodiment, the acrylic resin material is used for the base material layer of a double-sided adhesive tape.

  FIG. 8 is a detailed cross-sectional view of a portion (reference numeral VIII) surrounded by an alternate long and short dash line in FIG. Here, the front part of the guide member 206 and the reading glass 32 and the configuration around it are shown in cross section. The guide member 206 is formed by bending, for example, a metal plate-like material. As shown in FIG. 8, the front end of the guide member 206 is bent upward, and this portion serves as a mounting flange 206a. An attachment portion 200a is formed inside the document conveying device 200, and a front portion of the guide member 206 is attached to the attachment portion 200a by an attachment flange 206a. In this state, the displacement of the front portion of the guide member 206 with respect to the document conveying device 200 is restricted.

  A vibration isolator 222 is installed in the image reading unit 16 below the reading glass 32. When viewed in the front-rear direction of the reading glass 32, the vibration isolator 222 is located rearward (leftward in FIG. 8) from the front end of the reading glass 32, and extends in the width direction of the reading glass 32 at this position. The vibration isolator 222 supports the front end portion of the reading glass 32 from below and prevents vibration of the reading glass 32 during transportation of the image forming apparatus 10. As the vibration isolator 222, an anti-vibration rubber (for example, natural rubber, styrene rubber, chloroprene rubber, butyl rubber, ethylene-propylene rubber, etc.) effective for reducing vibration is used.

  As shown in FIG. 8, when the document conveying device 200 is closed, the front end portion of the guide member 206 is in contact with the upper surface of the gap securing member 220. In this state, a gap H (original conveyance path) for allowing the original to pass is secured between the lower surface of the guide member 206 and the upper surface of the reading glass 32. Within this gap H, it is possible to transport the document within the range up to the rear end of the clearance securing member 220 (the transport range in the figure). As long as the gap H can be secured stably, the gap securing member 220 may be an elastic body such as hard rubber.

[Configuration of rear part]
Next, FIG. 9 is a detailed cross-sectional view of a portion (symbol IX) surrounded by an alternate long and short dash line in FIG. Here, the rear portion of the guide member 206 and the reading glass 32 and the configuration of the periphery thereof are partially shown in cross section. On the rear side portion of the guide member 206, a protruding portion 206c slightly protruding from the lower surface is formed. The rear portion of the guide member 206 is in contact with the upper surface of the reading glass 32 at the protruding portion 206c. As a result, it is possible to convey the document within the range (conveyance range in the drawing) up to the protruding portion 206c in the gap H at the rear portion of the guide member 206.

  A rear portion of the guide member 206 is supported by the document feeder 200 via a coil spring 224. A receiving portion 206 b for fixing the coil spring 224 in the document feeder 200 is formed on the rear side portion of the guide member 206. The receiving portion 206b extends horizontally at a position slightly above the protruding portion 206c, and its upper surface is formed as a mounting surface for the coil spring 224. The coil spring 224 is compressed between the receiving portion 206 b and the main body of the document feeder 200. In this state, the rear portion of the guide member 206 receives the repulsive force of the coil spring 224 and is pressed against the upper surface of the reading glass 32, so that the protruding portion 206 c normally does not float from the upper surface of the reading glass 32. However, the rear portion of the guide member 206 is not restrained from being displaced in the vertical direction with respect to the document feeder 200 unlike the front portion thereof. Accordingly, the rear portion (projecting portion 206c) of the guide member 206 can slightly float from the upper surface of the reading glass 32 against the repulsive force of the coil spring 224 from the state shown in FIG. Due to the vertical displacement of the guide member 206, the gap H is appropriately expanded when the original is conveyed. Therefore, smooth conveyance of the original is maintained while preventing the original from being caught in the gap H. It becomes possible.

[When opening and closing the document feeder]
Next, an operation when the document feeder 200 is opened and closed will be described.
FIG. 10 shows a state in which the document feeder 200 is opened (bounced up). The right direction in FIG. 10 corresponds to the front direction facing the user who operates the image forming apparatus 10, and the upward direction corresponds to the upward direction of the image forming apparatus 10. In this state, since the rear portion of the guide member 206 is greatly separated from the upper surface of the reading glass 32, the rear portion of the guide member 206 is pushed down by the repulsive force of the coil spring 224. In this state, the guide member 206 is in contact with a stopper (not shown).

  When the document conveying apparatus 200 is closed from the state of FIG. 10, the protruding portion 206 c of the guide member 206 first comes into contact with the upper surface of the reading glass 32. When the document conveying device 200 is closed to the end after the protruding portion 206c contacts the reading glass 32, the coil spring 224 is compressed so that the rear portion of the guide member 206 is brought into the document conveying device 200. The guide member 206 finally settles in the position shown in FIG. During this time, the load when the protruding portion 206c comes into contact with the upper surface of the reading glass 32 is absorbed and relaxed by the elasticity of the coil spring 224. Therefore, an excessive point load does not particularly act on the reading glass 32.

  FIG. 11 shows a state in which a load is applied to the front side portion of the reading glass 32 when the document conveying device 200 is closed from the state of FIG. 10 in comparison with the present embodiment and the comparative example. The right direction in FIG. 11 matches the front direction facing the user who operates the image forming apparatus 10, and the upward direction matches the upward direction of the image forming apparatus 10. FIG. 11A shows a state in which a load is applied when the gap securing member 220 of the present embodiment is used. On the other hand, FIG. 11B shows a state in which a load is applied when a comparative example (conventional example) compared with the present embodiment is used.

  When the gap securing member 220 of this embodiment is used, the front portion of the guide member 206 is in contact with the gap securing member 220 on the surface. Therefore, the load applied to the reading glass 32 when the document feeder 200 is closed is a load distributed on the contact surface between the guide member 206 and the gap securing member 220.

  On the other hand, the gap securing member is not used in the comparative example, and the guide member 206 is in direct contact with the reading glass 32. A protrusion 226 a is formed on the front side portion of the guide member 206 of the comparative example in order to ensure a gap through which the document passes between the lower surface and the upper surface of the reading glass 32. In this case, the load applied to the reading glass 32 when the document conveying device 200 is closed is a load concentrated on the point where the protruding portion 226a of the guide member 206 contacts.

From the comparison between the present embodiment and the comparative example described above, the following points become clear.
(1) In the comparative example, since the load applied to the reading glass 32 is concentrated in a narrow range (contact point with the protruding portion 206c), the reading glass 32 is likely to be damaged such as cracks and chips. On the other hand, in the present embodiment, since the load applied to the reading glass 32 is distributed over a wide range, damage such as cracking or chipping of the reading glass 32 is less likely to occur than in the comparative example.

(2) In both the present embodiment and the comparative example, a vibration isolating material 222 is installed at a position below the reading glass 32, and the vibration isolating material 222 serves as a fulcrum of the reading glass 32. In a mode in which the protruding portion 226a of the guide member 206 contacts the front side of the vibration isolator 222 as in the comparative example, a large bending moment is generated around the vibration isolator 222 as a fulcrum due to the concentrated load. Are prone to cracking. On the other hand, in this embodiment, since the load is distributed at a position closer to the front than the antivibration material 222, an excessive bending moment that causes damage to the reading glass 32 does not occur.

  The inventor of the present invention has verified both the present embodiment and the comparative example, and has obtained the following results. That is, as a result of a test in which the opening / closing operation of the document conveying device 200 was repeated up to about 100,000 times, the reading glass 32 was eventually damaged because the load was concentrated repeatedly at one place in the comparative example. On the other hand, since the load is dispersed in this embodiment, the reading glass 32 is not damaged even if the opening / closing operation is repeated about 100,000 times.

  Furthermore, in said verification, the inventor has obtained the following knowledge regarding the double-sided pressure-sensitive adhesive tape used for attaching the gap securing member 220 of the present embodiment. That is, as a double-sided pressure-sensitive adhesive tape for general industrial use, a nonwoven fabric material is used for the base material layer, but in this embodiment, a non-non-woven fabric material such as acrylic resin is used for the base material layer of the double-sided pressure-sensitive adhesive tape. According to the verification performed by the inventor, when the gap securing member 220 is attached with a double-sided pressure-sensitive adhesive tape using a nonwoven fabric material for the base material layer, the gap securing member 220 is not changed while the opening / closing operation of the document feeder 200 is repeated. It was confirmed that misalignment occurred. This is considered to be because a load was repeatedly applied to the gap securing member 220 and a sheared portion in the horizontal direction was generated inside the base material layer (nonwoven fabric).

  On the other hand, when the gap securing member 220 is attached to the base material layer with a double-sided adhesive tape using a non-nonwoven fabric acrylic resin as in this embodiment, the opening and closing operation of the document feeder 200 is repeated under the same conditions. However, the gap securing member 220 was not misaligned. From the above verification, it is possible to continue fixing the gap securing member 220 for a long period of time by attaching the gap securing member 220 with a double-sided adhesive tape using an acrylic resin of a non-woven fabric material for the base material layer. It can be said.

  In this embodiment, the gap securing member 220 is provided in the front portion of the reading glass 32 where a load is easily applied when the document conveying device 200 is opened and closed. Do not touch directly. For this reason, since the gap securing member 220 itself protects the reading glass 32, the reading glass 32 can be further prevented from being damaged.

  As described above, in this embodiment, the reading glass 32 is reliably prevented from being damaged. However, even if an extremely excessive impact is applied and the front portion of the reading glass 32 is damaged, the gap securing member 220 can prevent the reading glass 32 from being damaged. Scattering of glass fragments is effectively prevented.

The present invention is not limited to the above embodiments, and can be implemented with various modifications and element replacements.
In one embodiment, the guide member 206 is formed of a metal plate, but a glass fiber-containing resin material may be used instead.

  In the above embodiment, a copying machine has been described as an example of the image forming apparatus 10 to which the image reading apparatus is applied. However, the present invention describes a facsimile apparatus that transmits the read image information to a remote place, or image information. The present invention can also be applied to a scanner device that reads and inputs to a computer.

1 is a front view schematically showing an overall configuration of an image forming apparatus to which an image reading apparatus of an embodiment is applied. FIG. 3 is a perspective view showing an upper part of the image forming apparatus as viewed from the upper left front. FIG. 3 is a perspective view showing an upper portion of the image forming apparatus as viewed from the upper left front side with the document conveying device opened. FIG. 4 is a longitudinal sectional view in a vertical plane along line IV-IV in FIG. 2. It is a longitudinal cross-sectional view in the vertical plane which follows the VV line in FIG. FIG. 5 is a simplified view of a longitudinal section of the document conveying device taken along line VI-VI in FIG. 4. It is the top view which showed the left part of the image reading part. FIG. 5 is a detailed cross-sectional view of a portion (reference numeral VIII) surrounded by a one-dot chain line in FIG. 4. FIG. 5 is a detailed cross-sectional view of a portion (symbol IX) surrounded by a one-dot chain line in FIG. FIG. 6 is a partial cross-sectional view illustrating a state when the document conveying device is opened. FIG. 6 is a diagram illustrating a state in which a load is applied to a front portion of a reading glass when a document conveying device is closed, in comparison with the present embodiment and a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 16 Image reading part 31 Original plate glass 32 Reading glass 200 Original conveying apparatus 204 Hinge mechanism 206 Guide member 220 Clearance securing member 224 Coil spring

Claims (3)

An image reading unit having a reading surface for reading an original, and an original placed on the upper surface side of the image reading unit and sent to the lower surface side, and the image surface of the original is the reading surface An image reading apparatus that reads an image of a document by the image reading unit while conveying the document by the document conveying mechanism.
A hinge mechanism that connects the document conveying mechanism so that the image reading unit can be opened and closed up and down at one end edge thereof;
Of the image reading unit, the sheet-like glass material that forms the reading surface is provided at a portion corresponding to the other end edge facing the one end edge in a state where the document conveying mechanism is closed. A vibration isolator that prevents vibration of the glass material in a state of being supported from below at a position outside the road;
Wherein it is installed between the end edges along the lower surface of the document conveying mechanism and the other edge portion, located in the direction alignment from above with respect to the reading surface in a state in which the document conveying mechanism is closed downward Thus, a document conveyance path is formed between the reading surface and the document conveyed through the conveyance path is guided while facing the reading surface, and corresponds to the other edge portion. While the end portion restrains the displacement in the vertical direction with respect to the document conveying mechanism, the end portion corresponding to the one end portion is formed with a protruding portion that contacts the reading surface and secures a gap serving as the conveying path. A guided member;
Of the image reading unit, the document conveying mechanism is closed and the region corresponding to the other end edge portion covers the region outside the conveying path on the reading surface than the anti-vibration material. are arranged spread to large range, the surface contact with a range greater than the vibration-proof material from below with respect to the guide member when the document conveying mechanism is closed, the guide member and the reading surface in the surface contact state the gap securing member for securing the gap serving as the conveyance path between,
A pressure is provided at the one end edge of the document conveying mechanism to press the guide member toward the reading surface in a state where the document conveying mechanism is closed. A support mechanism that allows the guide member to be displaced in a direction away from the reading surface against the pressing force only at an end corresponding to the one end edge of the document conveying mechanism when passing. An image reading apparatus comprising: The image reading apparatus according to claim 1,
The image reading apparatus, wherein the gap securing member is stuck on the reading surface via a double-sided adhesive tape having a non-woven fabric material in a base material layer . An image forming apparatus for forming an image to be transferred to a printing paper based on an image read using the image reading apparatus according to claim 1.

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