JP4536608B2 - Document reader - Google Patents

Description

The present invention relates to a document reading apparatus having a document conveying equipment for conveying the original document.

  In recent years, document feeders (hereinafter also referred to as “ADFs”) that support a sheet-through method in which an image is read while a scanner portion is fixed and a document is conveyed at a predetermined speed have become widespread for reasons of productivity and space saving. ing. In a document reading apparatus equipped with this type of ADF, it is important to maintain a predetermined positional relationship with respect to an exposure unit in a portion facing the reading unit in order to maintain the image quality. It has been found that the variation in the positional accuracy of the direction has a great influence on the conveyance quality such as image density and jam.

  In order to ensure the positional accuracy in the height direction described above, for example, a height adjustment mechanism such as a spacer or a screw is added to the hinge for attaching the ADF to the scanner, or the support portion of the reading portion is directly adjusted. . These adjustment methods require the skills of skilled technicians (customer engineers in the market). Furthermore, it has been studied to automatically adjust the position accuracy in the height direction described above by the ADF mechanism.

  Here, FIG. 9 shows a configuration example for adjusting the positional accuracy in the height direction described above.

  In FIG. 9, the document reading apparatus has an ADF 200 ′ mounted on the contact glass 102 c of the main body 300. The ADF 200 ′ includes a transport frame 80 and a base (hereinafter referred to as “base”) 90 on which the transport frame 80 is mounted. The conveyance frame 80 includes a document table 81 on which the document bundle S (shown in FIG. 10) is placed, and various conveyance members and various guide members that convey the document taken out from the document table 81. These members form part or all of the transport path. The base 90 is connected to the main body 300 so as to be openable and closable by a connecting member (not shown) such as a hinge (for example, in the drawing, the back side is fixedly connected to the main body 300 and the front side is swingable. ).

  In addition, the bottom of the transport frame 80 has four protrusions 82a, 82b, 83a, and 83b that come into contact with the document scale 103c and the contact glass 102c of the main body 300. Further, the protrusions 82a and 82b are arranged opposite to both ends of the document scale 103c in the document width direction, and the protrusions 83a and 83b are downstream of the protrusions 82a and 82b in the document transport direction (hereinafter referred to as “transport direction”). The contact glass 102c is disposed opposite to both ends in the document width direction. In other words, the projections 82a, 82b, 83a, 83b are arranged so as to be substantially square when the contact points are connected.

  In this configuration, when the transport frame 80 is displaceable in the height direction, the balance of the center of gravity is based on the arrangement of the support portions (corresponding to the protrusions 82a, 82b, 83a, and 83b) of the transport frame 80 in the drawing. There is a case where it is biased to the right side (the center of gravity is indicated by arrow F in the figure). In this case, a clockwise moment (indicated by an arrow B) acts around the protrusions 83a and 83b, and tries to move the protrusions 82a and 82b upward (indicated by an arrow A). Further, as shown in FIG. 10, when a large number of documents (corresponding to the document bundle S) are placed on the document table 81 and the clockwise moment about the projections 83a and 83b is increased, the projections 82a and 82b are increased. One or both of them may be separated from the document scale 103c. In a configuration in which a so-called sheet-through type document reading is performed, the projections 82a and 82b are in the vicinity of the document reading position. Therefore, if the projections 82a and 82b are lifted from the document scale 103c as described above, the image density unevenness and speed are increased. Unevenness, such as slant feeding, will occur.

  On the other hand, a conventional document reading apparatus has a fixing member attached to a main body on an opening / closing mechanism (for example, a hinge) of a document pressing plate (corresponding to a conveyance frame) that presses the document, and the fixing member. A frame member that is pivotally supported at one end, a support member that is provided on the free end side of the frame member, and that supports the document crimping plate in a swingable manner, and a fixed end of the frame member that is supported by the support member Urging means (for example, an urging device 50 having a compression spring) that urges the document crimping plate in a direction opposite to the closing direction is provided on the side (for example, on the center of gravity line LG). When closing, the crimping portion on the fixed end side of the frame member is first brought into contact with the platen glass, and the self-weight rotation moment is applied so that the crimping portion on the free end side of the frame member is brought into contact with the platen glass by the biasing means. Are (for example, see Patent Document 1).

  In addition, magnets and magnetic members are arranged opposite to each other at at least two locations on the opposite side of the open / close hinge side of the document crimping plate, and at least two locations on the corresponding platen glass side, respectively, and the document crimping plate is closed. Some hold the plate with a magnetic coupling force (see, for example, Patent Document 2).

The document reader further includes a first reading unit for reading the document surface on the main body side, a second reading unit for reading the document back side on the ADF side, and a thick document positioning member in the book mode. Some also serve as a second back plate facing the two reading means and a positioning member in the height direction with respect to the contact glass of the second reading means (for example, see Patent Document 3).
Japanese Patent Laid-Open No. 2001-242561 (page 3, FIG. 1, etc.) Japanese Utility Model Publication No. 63-115141 (first page, FIG. 2 etc.) Japanese Patent Laid-Open No. 11-32164 (page 3, FIG. 1, etc.)

  However, the conventional document reading apparatus according to Patent Document 1 requires a biasing means that biases the document crimping plate in a direction opposite to the closing direction of the document crimping plate. It was. Further, in the conventional document reading apparatus according to Patent Document 2, since the magnet and the magnetic member are arranged opposite to each other on the document pressure plate side and the platen glass side, there is a problem that the number of components increases and the cost increases. . Further, in the conventional document reading apparatus according to Patent Document 3, there is room for further improvement in that the position accuracy of the first reading unit with respect to the contact glass in the height direction is adjusted.

  The present invention has been made in order to solve the conventional problems, and can convey a document in which the positional relationship in the height direction between the reading conveyance unit (including the conveyance frame) and the contact glass can be stabilized with a simple configuration. An object is to provide an apparatus and a document reading apparatus.

Document reading apparatus of the present invention according to claim 1, a first structure having a center of gravity to one side of the document length direction with respect to the reading position and having a transfer means for transferring to the reading of the original position, and the a document feeder which is configured to include a second structure supporting equipped with a first structure, and having a reading position on the upper surface, reads the document conveyed to the reading position by the document feeder An original reading apparatus comprising: a main body having reading means ; and a connecting means for connecting the second structure to the upper surface of the main body so as to be openable and closable , the original width direction of the first structure The center of gravity of the first structure that is biased toward the other end side in the document width direction from the center in the document width direction on the one end side and the other end side in the document length direction from the reading position . a first protrusion formed on the bottom surface, the first In concrete body document width direction other end side of, and the center of gravity and the reading position to form a second protrusion that faces the first protrusion on the bottom of the document length direction of the other end, said first A third protrusion is formed on the other end side of the one structure in the document width direction and on the bottom surface on the one end side in the document length direction from the center of gravity , and the first protrusion to the third protrusion are In the closed state, the second structure passes through the second structure and comes into contact with the upper surface of the main body .

With this configuration, the first and second protrusions are arranged on the center of gravity of the first structure and the bottom surface on the other end side in the document length direction from the reading position , and the third protrusion is positioned on the center of gravity of the first structure. placed in a document length direction of the one end of the bottom surface than, since the third projection from the first and so through the second structure in contact with the upper surface of the body, which can be opened and closed (e.g., high The positional relationship in the height direction with respect to the main body of the first structure mounted on the second structure that can be displaced in the vertical direction can be stabilized. In other words, the first to third protrusions are distributed and arranged upstream and downstream of the center of gravity of the first structure, so that no complicated configuration is required and the center of gravity of the first structure is generated. It is possible to avoid the influence of the moment to be performed and to determine the positional relationship in the height direction with the contact glass at the reading position.

In here, the center of gravity line means a straight line extending in the document width direction through the center of gravity of the first structure. The document width direction refers to a direction perpendicular to the document transport direction (document length direction) .
According to a second aspect of the present invention, there is provided the original reading apparatus according to the first aspect, wherein the first structure is disposed on one end side in the original width direction of the first structure and on the bottom surface on one end side in the original length direction with respect to the center of gravity. A fourth protrusion is formed, and the fourth protrusion is in contact with the upper surface of the second structure.
With this configuration, the front side is prevented from floating due to the elasticity of the first structure itself due to the urging force of the connecting means by the load of the fourth protrusion, so the first structure due to the elasticity of the first structure itself. The influence of the bending of the body is eliminated or reduced, and the position of the first structure in the height direction with respect to the main body can be reliably determined.

According to a third aspect of the present invention, there is provided the document reading apparatus according to the second aspect, wherein the second structure has a structure in which the length in the document length direction is longer than the length in the document length direction of the first structure. The first structure is mounted on the other end side in the document length direction among one end side and the other end side in the document length direction, and one end in the document width direction of the second structure body A fifth protrusion is formed on a bottom surface of the end portion of the second structure body that is separated from the mounting position of the first structure body on one end side in the document length direction of the second structure body; projection has a configuration in which the second structure was made to contact with the upper surface of the main body in the closed state.
With this configuration, the fifth protrusion is formed on the bottom surface of the end portion separated from the mounting position of the first structure on the one end side in the document length direction of the second structure. This can cope with the case where the structure does not have sufficient rigidity, and can reduce the influence of the change in the center of gravity of the displaceable first structure due to document stacking. Therefore, it is possible to stably regulate the position of the first structure with respect to the main body in the height direction.

According to a fourth aspect of the present invention, there is provided an image forming apparatus for forming an image of a document read by the document reading device according to any one of the first to third aspects and a document read by the document reading device on a recording medium. And means.

The present invention can provide an image scanning apparatus has an effect that it is possible to stabilize the positional relationship in the height direction of the transport unit and the contact glass read by easy easy Do construction.

  Hereinafter, a document conveying device and a document reading device according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows a document reading apparatus according to a first embodiment of the present invention.

  In FIG. 1, a document reading apparatus 100 transports a document (not shown) placed on a document table 2 in a predetermined transport direction (indicated by an arrow in the figure) to a reading position (indicated by a Δ in the figure). In addition, the apparatus further includes a document conveying apparatus (hereinafter also referred to as “ADF”) 200 that aligns and discharges the read document on the discharge tray 14 and a main body 300 on which the ADF 200 is mounted. The ADF 200 is fixedly connected to the main body 300 on the back side (right side in FIG. 3) by connecting members such as hinges 25a and 25b (shown in FIG. 2), and the front side (left side in FIG. 3) can be freely opened and closed. It is configured. The hinges 25a and 25b have a built-in coil spring, for example, have an upward moment, and are configured to urge the base 40 upward. This configuration is for facilitating the user's opening operation. Here, when the ADF 200 is in the middle of opening, the ADF 200 is held at an arbitrary opening position due to the balance between the upward moment and the weight of the ADF 200. The bottom surface of the ADF 200 functions as a pressure plate that presses the document placed on the contact glass 102b when the ADF 200 is closed.

  The main body 300 includes a reading unit 101 that reads a document conveyed to a reading position on the contact glasses 102a and 102b, a driving unit that moves (moves in the horizontal direction in the drawing) and drives the reading unit 101, and a reading unit. And a main body control unit (not shown) for controlling the reading operation 101. Here, the reading unit 101 includes a reading element including, for example, an exposure lamp (not shown), a first mirror, a lens, and a CCD.

  Further, the main body 300 stops the exposure lamp and the first mirror below the contact glass 102a, and reads the document placed on the document table 2 while transporting the document to the reading position (so-called sheet-through reading method). And a pressure plate mode for reading a document placed on the contact glass 102b by moving the exposure lamp and the first mirror below the contact glass 102b in the horizontal direction in the figure. The operation display unit (not shown) is provided.

  This operation display section has various button keys such as a start button and a numeric keypad, and an LCD display. Setting display of each operation mode (including ADF reading mode and fixed reading mode) and instructions to start and stop the operation Is configured to be possible by user operation. The contents input and set from the operation display unit are stored in the RAM of the main body control unit, and the stored contents are updated every time the setting contents are changed.

  The ADF 200 includes a document table 2, various rollers 5, 6, 7, 7a, 8, 8a, 10, 10a, 11, 11a, various sensors (for example, optical reflective sensors) 21, 22, 23, and a discharge unit. A paper tray 14 and the like are provided. These are arranged on the conveyance path.

  Here, the document table 2 constitutes a document setting unit for setting a document bundle. A sheet feeding member 5 (for example, a sheet feeding roller) and a separation member 6 (for example, a separation roller) separate and feed the documents one by one from the document bundle (or document) placed on the document table 2. A separation sheet feeding unit is configured.

  The abutting sensor 21, the abutting roller pair (the abutting driving roller 7 and the abutting driven roller 7a), and the registration sensor 22 are aligned by first abutting the original fed from the separation sheet feeding unit. A registration unit that pulls out and conveys the original. An entrance roller pair (entrance drive roller 8 and entrance follower roller 8a) and an exit roller pair (exit drive roller 10 and exit follower roller 10a) invert the document conveyed by the resist unit, and the document surface of the contact glass 102a is reversed. A reversing conveyance unit is configured to be read from below.

  In the vicinity of the reading position of the reverse conveying unit, the conveying gap is made as narrow as possible so as to suppress the degree of freedom of the document as much as possible. For example, a flexible guide member (not shown) is projected from the vicinity toward the white background plate 104 facing the contact glass 102a so as to fill the transport gap. The white background plate 104 is held on the contact glass 102a with a gap of about 0.5 mm ± 0.2 mm so as to suppress an error in the reading direction.

  The paper discharge sensor 23 and a pair of paper discharge rollers (a paper discharge drive roller 11 and a paper discharge driven roller 11a) constitute a paper discharge unit that conveys the read original to the paper discharge tray 14. The paper discharge tray 14 constitutes a stack unit for stacking and holding originals after reading.

  Furthermore, the ADF 200 includes a drive unit (for example, various motors and various solenoids (not shown)) that transports the above-described units, and an ADF control unit (not illustrated) that controls a series of transport operations. The ADF control unit transmits detection information (signals) from the various sensors described above to the main body control unit, and controls the driving unit based on a control signal transmitted from the main body control unit.

  As shown in FIG. 2, the ADF 200 includes a document frame, a separation feeding unit, a registration unit, a conveyance frame 30 including the reverse conveyance unit, and a base 40 including the stack unit. It is. Since the carrier frame 30 is mounted on the base 40, it can move in the vertical direction (corresponding to the height direction) in accordance with the opening and closing operation of the base 40. Moreover, the conveyance frame 30 includes all or part of the reading part (part facing the reading position) and the conveying path on which each part is arranged.

3 and 4 show a plan view and a cross section of the main part of the document reading apparatus according to the first embodiment of the present invention.
In the present embodiment and second and third embodiments described later, the downstream in the transport direction means one end side in the document length direction in the document reading apparatus according to the present invention, and the upstream in the transport direction means The other end side in the document length direction in the document reading apparatus according to the present invention is meant.

  3 and 4, three protrusions 41, 42, and 43 are formed on the bottom surface of the conveyance frame 30, and all of the protrusions 41, 42, and 43 are in contact with the main body 300 through the base 40. The protrusions 41, 42, and 43 define the positional relationship between the reading position of the main body 300 and the height direction of the transport frame 30. Here, the protrusions 41 and 42 are in contact with the document scale 103a upstream of the reading position in the transport direction, and the contact positions 41 'and 42' are opposed in the document width direction. The protrusion 43 is disposed along the same bottom side of the transport frame 30 together with the protrusion 42 and is in the vicinity of the hinge 25a. Further, the protrusion 43 contacts the back scale (not shown) downstream in the transport direction from the reading position, and the contact position 43 ′ is downstream in the transport direction from the contact position 42 ′ and the center of gravity G of the transport frame 30. And in the vicinity of the center of gravity line LG (including the center of gravity G) of the transport frame 30. The back scale is formed perpendicular to the document scales 103a and 103b, and extends downstream in the transport direction of the document scale 103b near the hinges 25a and 25b on the back side (right side in FIG. 3). Here, since the protrusions 42 and the protrusions 43 are arranged with the center of gravity line LG in between, the posture of the transport frame 30 becomes more stable as the distance between both increases. In the present embodiment, since the drive system of the transport frame 30 is disposed on the back side (right side in FIG. 3) and the mass ratio on the back side is high, the center of gravity G is also biased to the back side.

  According to the ADF 200 according to the first embodiment of the present invention, the transport frame 30 (the first frame) having the various rollers that transport the document to the reading position, the various sensors, and the like (corresponding to a transport unit). And a base 40 (corresponding to a second structure) on which the conveyance frame 30 is mounted and supported, and the upper surface of the main body 300 of the document reading apparatus 100 and the base 40 are hinges 25a, 25b, the document frame 30 has both ends open in the document width direction (left end side and right end side in FIG. 3) and in the vicinity of the reading position and the reading position upstream of the center of gravity G. Are formed on one end side in the document width direction on the bottom surface of the transport frame 30 (on the right end side in FIG. 3) and from the center of gravity G. Transport method A protrusion 43 (corresponding to a third protrusion) is formed in the vicinity of the downstream center line of gravity LG, and the protrusions 41, 42, 43 pass through the base 40 and abut the upper surface of the main body 300 when the ADF 200 is closed. I am doing so. This configuration corresponds to an embodiment of the present invention according to claim 1.

  Here, since the protrusions 41 and 42 are disposed in the vicinity of the reading position and the protrusion 43 is disposed downstream of the center of gravity G of the transport frame 30 in the transport direction, the influence of the moment generated by the center of gravity position of the transport frame 30 is avoided. The base 40 that can be displaced in the height direction by the opening / closing operation and the positioning of the conveyance frame 30 in the height direction with respect to the main body 300 (including the contact glass 102a) can be performed. That is, only the three protrusions 41, 42, and 43 are formed on the bottom surface of the conveyance frame 30, and the height positional relationship between the upper surface of the main body 300 and the ADF 200 at the reading position is stabilized without requiring new parts. Can do. Further, since the three protrusions 41, 42, 43 on the bottom surface of the transport frame 30 abut on the main body 300, it is easier for any one of the protrusions to be separated from the main body 300 compared to the case where four or more similar protrusions are provided. Can be prevented.

Further, according to the present embodiment, the center of gravity G of the transport frame 30 is biased toward the protrusion 43 side from the center in the document width direction. This is because the mass ratio is increased on the back side due to the arrangement of the drive system of the transport frame 30 . This Kodewa, depending on the deviation of the center of gravity G, by arranging the projections 43 in the vicinity of the center of gravity line LG, (in FIG. 3, right) rear side of the conveyor frame 30 when the load is applied to the load balance in the document width direction Can take. Therefore, regardless of the deviation of the center of gravity G, the displacement of the conveyance frame 30 in the height direction with respect to the main body 300 (including the contact glass 102a) can be suppressed, and the protrusion 41 side can be prevented from being separated from the main body 300.

  In the above-described embodiment, the case where the document scale 103a is used as the portion of the main body 300 that contacts the protrusions 41 and 42 has been described. However, the present invention is not limited to the frame portion or the contact glass outside the document scale 103a. Even if 102a or the like is used, the same effect can be obtained.

  In the above-described embodiment, the case where the back scale is used as the portion of the main body 300 that comes into contact with the protrusion 43 has been described. However, the present invention also includes a frame portion outside the back scale, or a contact glass 102b. Even if it is used, the same effect can be obtained.

  In the above-described embodiment, the case where the protrusion 43 is arranged in the vicinity of the center of gravity line LG and in the vicinity of the hinge 25a has been described. However, in the present invention, the protrusion 43 is arranged in the vicinity of the center of gravity G on the center of gravity line LG. The same effect can be obtained.

  Next, a document reading apparatus according to the second embodiment of the present invention will be described. This is different from the first embodiment in that a protrusion 44 is provided on the bottom surface of the transport frame 30. In addition, the same code | symbol is provided to the same structure as 1st Embodiment, and description is partially abbreviate | omitted.

  5 and 6 show a plan view and a cross section of the main part of an original reading apparatus according to the second embodiment of the present invention.

  5 and 6, the above-described three protrusions 41, 42, and 43 are formed on the bottom surface of the conveyance frame 30, and all of the protrusions 41, 42, and 43 pass through the base 40 and contact the main body 300. Further, in this embodiment, a protrusion 44 is formed on the bottom surface of the transport frame 30. The protrusion 44 is disposed along the same bottom side of the conveyance frame 30 together with the protrusion 41, and is on the near side (left side in FIG. 5) of the document reading apparatus 100. Further, the protrusion 44 contacts the base 40 downstream in the transport direction from the reading position, and the contact position 44 ′ is downstream in the transport direction from the contact position 41 ′, and the barycentric line LG ( Near the center of gravity G).

  Here, the upward moment by the hinges 25a and 25b acts on the base 40 as described above. Due to this action, the transport frame 30 may be bent by the elasticity of the frame itself. In this case, in the configuration of the first embodiment, since no protrusion is formed on the right front side (left side in FIG. 5) of the transport frame 30, the right front side is lowered by the weight of the transport frame 30, and the transport frame 30 It is assumed that the distance in the height direction of the main body 300 changes. However, when a protrusion 83a is formed as shown in FIG. 10 and this protrusion 83a contacts the main body 300, the protrusions 82a and 82b near the reading position are separated from the main body 300 by the moment indicated by the arrow B.

  On the other hand, in this embodiment, since the protrusion 44 is in contact with the base 40 in the vicinity of the center of gravity line LG, the pressure (load) applied to the base 40 of the transport frame 30 acts downward at the contact position 44 ′. The applied pressure and the upward moment are substantially canceled out. Accordingly, it is possible to prevent the protrusions 41 and 42 near the reading position from being separated from the main body 300 due to the upward moment.

According to the document reading apparatus 100 according to the second embodiment of the present invention, the base 40 (on the center of gravity line LG of the transport frame 30 (corresponding to the first structure) and in the vicinity of the protrusion 43 is provided. A hinge 25a (corresponding to the connecting means) for connecting the second structure and a reading unit 101 (corresponding to the reading means) for reading the document conveyed to the reading position. In the configuration in which the base 40 is urged upward, the projection 44 on the front side of the bottom surface of the transport frame 30 (on the left side in FIG. 5 (corresponding to one end in the document width direction)) and in the vicinity of the center of gravity line LG. (Corresponding to the fourth protrusion) is formed, and the protrusion 44 is in contact with the upper surface of the base 40 .

  With this configuration, the front side is prevented from floating due to the elasticity of the transport frame 30 due to the urging by the hinge 25a by the load due to the protrusion 44, so the influence of the deflection of the transport frame 30 due to the elasticity of the transport frame 30 itself is eliminated. In other words, the position of the conveyance frame 30 with respect to the main body 300 (including the contact glass 102a) can be determined with certainty.

  In the above-described embodiment, the base 40 is pushed from above by the leg-shaped protrusions 44 formed on the bottom surface of the transport frame 30, but is limited to the formation of leg-shaped protrusions on the transport frame 30 side. It is not something. In addition to this, for example, a similar effect can be obtained by forming a columnar portion (corresponding to a protrusion) on the upper surface of the base 40 so that the columnar portion contacts the bottom surface of the transport frame 30. . That is, it is only necessary that the load on the transport frame 30 is applied to the base 40 from the vicinity of the center of gravity line LG.

  Further, in the above-described embodiment, the case where the protrusion 44 is arranged in the vicinity of the center of gravity line LG and on the end in the document width direction (left end in FIG. 5) has been described. The same effect can be obtained even if it is arranged on the upper side and on the near side (left side in FIG. 5) or on the downstream side in the transport direction and on the near side (for example, a position facing the protrusion 43).

  Next, a document reading apparatus according to the third embodiment of the present invention will be described. This is different from the second embodiment in that a protrusion 45 is provided on the bottom surface of the base 40. In addition, the same code | symbol is provided to the same structure as 2nd Embodiment, and description is partially abbreviate | omitted.

  7 and 8 show a plan view and a cross section of the main part of an original reading apparatus according to the third embodiment of the present invention.

7 and 8, the above-described three protrusions 41, 42, and 43 are formed on the bottom surface of the conveyance frame 30, and all of the protrusions 41, 42, and 43 pass through the base 40 and contact the main body 300. On the bottom surface of the conveyance frame 30, a protrusion 44 is disposed along the same bottom side of the conveyance frame 30 together with the protrusion 41, and is on the near side (left side in FIG. 7) of the document reading apparatus 100. Further, the protrusion 44 is in contact with the base 40 in the vicinity of the center of gravity line LG downstream of the reading position in the transport direction. Further, in the present embodiment, a protrusion 45 is formed on the bottom surface of the base 40. The protrusion 45 is on the right front side of the base 40 (lower left side in FIG. 7). Further, the protrusion 45 contacts the main body 300 downstream of the center of gravity line LG in the transport direction, and the contact position 45 ′ is downstream of the contact position 44 ′ in the transport direction and downstream of the base 40 in the transport direction. It is on the front side of the end (the end separated from one end in the document length direction) .

  Here, for example, when the base 40 is made of a mold, it is assumed that the base 40 itself is bent when a load is applied to the base 40 by the protrusion 44 on the bottom surface of the transport frame 30. Further, it is assumed that the balance is lost due to a difference in torque between the left and right hinges 25a and 25b, a backlash of the document feeder 100, and the like. Therefore, in the present embodiment, the protrusion 45 is formed on the right front side of the base 40. This is because the protrusion 45 is separated from the reading position as much as possible, and is arranged on the right side of the base 40 or in the vicinity thereof, so that the protrusions 41 and 42 are lifted from the main body 300 (A shown in FIGS. 9 and 10). This is to prevent the action of (see). When the protrusion 45 is close to the center of gravity G of the transport frame 30, a moment around the protrusion 45 is generated, and the protrusions 41 and 42 near the reading position may be separated from the main body 300.

According to the document reading apparatus 100 according to the third embodiment of the present invention, the downstream side in the transport direction (corresponding to one end side in the transport direction) of the bottom surface of the base 40 (corresponding to the second structure). And a protrusion 45 (corresponding to a fifth protrusion) on the front side (lower left side in FIG. 7) downstream of the reading position and the center of gravity G of the transport frame 30 (corresponding to the first structure). , And the protrusion 45 is in contact with the upper surface of the main body 300 .

  With this configuration, since the protrusion 45 is separated from the center of gravity G of the transport frame 30 toward one end side (the lower end side in FIG. 7) of the main body 300 in the transport direction, it corresponds to the case where the base 40 does not have sufficient rigidity. In addition, it is possible to reduce the influence of the change in the center of gravity of the displaceable transport frame 40 due to document stacking. Therefore, it is possible to stably regulate the position of the conveyance frame 30 in the height direction with respect to the main body 300 (including the contact glass 102a).

  Furthermore, in this embodiment, as shown in FIGS. 1 and 2, since the document table 2 is directly attached to the conveyance frame 30, the relative positional relationship of the conveyance parts does not change, and there is an advantage in conveyance. On the other hand, the position of the center of gravity of the transport frame 30 on which the document is loaded changes depending on the mass of the document loaded on the document table 2. On the other hand, by arranging the protrusion 45 on the right side of the base 40 or in the vicinity thereof as described above, it is possible to improve the robustness with respect to the number of stacked originals.

  In the first to third embodiments described above, the document reading apparatus 100 including the ADF 200 has been described. However, the present invention is applied to an image forming apparatus including the document reading apparatus 100 described above. The same effect can be obtained. In addition to the document reading apparatus 100, the image forming apparatus includes an image forming unit (such as an image forming unit (not shown)) for transferring an image of a document read by the reading unit 101 onto a transfer sheet.

  In this configuration, the reading unit 101 has an optical system such as an exposure lamp (not shown), a first mirror, and a lens as described above, and the exposure lamp and the first mirror are stopped below the reading position to perform exposure. After irradiating light onto the image surface by the lamp, the reflected light is imaged on an image sensor composed of a CCD via a first mirror and an optical system, and the optical signal is converted into an electrical signal (corresponding to image data) by this image sensor. ). The image data is output to the main body control unit, and the input image data is written on a photosensitive drum constituting the image forming unit by a writing optical system to form an electrostatic latent image. A visible toner image is formed on the photosensitive drum by the charging unit, the exposing unit, and the developing unit. On the other hand, under the control of the main body control unit, transfer paper fed from a transfer paper feeding system (not shown) is conveyed to the image forming unit in accordance with the image forming operation, and is transferred by the transfer unit constituting the image forming unit, The toner (toner image) is transferred to the first surface of the transfer paper, and further, the toner is fixed by a fixing system (not shown), and then conveyed to a transfer paper discharge unit (not shown).

1 is a cross-sectional view of a document reading apparatus according to a first embodiment of the present invention. 1 is an exploded view of a document conveying device according to a first embodiment of the present invention. 1 is a plan view of a document conveying device according to a first embodiment of the present invention. 1 is a cross-sectional view of a main part of a document reading apparatus according to a first embodiment of the present invention. FIG. 6 is a plan view of a document conveying device according to a second embodiment of the present invention. It is principal part sectional drawing of the original document reading apparatus which concerns on the 2nd Embodiment of this invention. FIG. 6 is a plan view of a document conveying device according to a third embodiment of the present invention. It is principal part sectional drawing of the original document reading apparatus which concerns on the 3rd Embodiment of this invention. FIG. 10 is a cross-sectional view of a main part of a conventional document reading apparatus. FIG. 10 is a cross-sectional view of a main part of a conventional document reading apparatus (when a document is placed).

Explanation of symbols

2 Document table 14 Paper discharge tray 30 Transport frame 40 Base 41, 42, 43, 44, 45 Projection 100 Document reading device 101 Reading unit 102 a, 102 b Contact glass 103 a, 103 b Document scale
200 Document feeder (ADF)
300 body

Claims (4)

A first structure having transport means for transporting the document to the reading position and having a center of gravity on one end side in the document length direction with respect to the reading position, and a second structure on which the first structure is mounted and supported. A document conveying device configured to include the structure of
And has a reading position on the upper surface, a body having a reading means for reading the conveyed document to the reading position by the document feeder,
A document reading device comprising: a connecting unit that connects the second structure to the upper surface of the main body so as to be openable and closable;
From the center of gravity of the first structure and the reading position that are biased to one end side in the document width direction of the first structure and from the center in the document width direction of the first structure toward the other end side in the document width direction. Forming a first protrusion on the bottom surface on the other end side in the document length direction ,
Forming a second protrusion that faces the first protrusion on the bottom of the document length direction of the other end side of the document width direction end side and the center of gravity and the reading position of the first structure And
Forming a third protrusion on the other end side in the document width direction of the first structure and on the bottom surface on one end side in the document length direction from the center of gravity;
The original reading, wherein the first protrusion to the third protrusion pass through the second structure and contact the upper surface of the main body when the second structure is in a closed state. apparatus. Forming a fourth protrusion on one end side in the document width direction of the first structure and on the bottom surface on one end side in the document length direction from the center of gravity;
The document reading apparatus according to claim 1, wherein the fourth protrusion is in contact with an upper surface of the second structure . The second structure has a structure in which the length in the document length direction is longer than the length in the document length direction of the first structure, and is one of the one end side and the other end side in the document length direction. The first structure is mounted on the other end side in the document length direction,
The second structure body is positioned on one end side in the document width direction and on the bottom surface of the end portion separated from the first structure body mounting position on one end side in the document length direction of the second structure body. 5 protrusions are formed,
The document reading apparatus according to claim 2, wherein the fifth protrusion is configured to contact an upper surface of the main body when the second structure is in a closed state . 4. An image forming apparatus comprising: the document reading device according to claim 1; and image forming means for forming an image of the document read by the document reading device on a recording medium. apparatus.

Images