Document feeder and image forming apparatus

Abstract

To provide a document feeder that can prevent the occurrence of failure in ejection of a document even when the height of the document feeder is reduced and warpage occurs, and an image forming apparatus.SOLUTION: A document feeder comprises a conveyance guide that conveys a document, and a pair of ejection rollers that eject the conveyed document to a document loading tray, and include a driving roller and a driven roller. The conveyance guide includes a conveyance lower guide pivotally rotatably supported on a housing including the document loading tray. In a state where the conveyance lower guide is closed relative to the body of the document feeder, an engagement part provided on the conveyance lower guide engages with a part to be engaged provided on the housing. In a state where the conveyance lower guide is rotated from the state where the conveyance lower guide is closed to be opened relative to the body of the document feeder, the engagement of the engagement part with the part to be engaged is cancelled.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present disclosure relates to a document feeder and an image forming apparatus. [Background technology]

[0002] Conventionally, there has been known a document feeder that continuously conveys paper (documents) for purposes such as reading images of the documents. For example, Patent Document 1 describes a document feeder in which a guide unit that guides the documents is integrally provided on the frame of the document feeder. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-368953 Summary of the Invention [Problem to be solved by the invention]

[0004] In document feeders, if an attempt is made to design the height of the document feeder lower while maintaining the paper stacking height in the base tray, including the document stacking tray onto which the transported paper is discharged, the height of the ribs (walls) formed on the base tray onto which the transported paper is discharged must be lowered. In particular, the height of the ribs near the driven roller must be further lowered. However, lowering the height of the ribs weakens the strength of the base tray. As a result, the lack of strength can cause the base tray to warp or deform, resulting in problems with paper transport.

[0005] In particular, the lower transport guide that guides the document onto the base tray is rotatably supported on the base tray and also supports a driven roller for transporting the document, but due to the warping of the base tray, the pressure of the driven roller against the drive roller becomes weaker, which can sometimes prevent the document from being sandwiched between the drive roller and the driven roller for transport.

[0006] The present disclosure has been made in consideration of the above-mentioned problems, and an object of the present disclosure is to provide a document feeder and an image forming apparatus that can prevent document discharge failures even if the height of the document feeder is lowered and warping occurs. [Means for solving the problem]

[0007] A document feeder according to an embodiment of the present disclosure includes: a transport guide for transporting the document; a pair of discharge rollers including a drive roller and a driven roller for discharging the transported document onto a document stacking tray; A document feeder comprising: the transport guide includes a transport lower guide pivotally supported on a housing including the document stacking tray, When the lower transport guide is closed relative to the main body of the document feeder, an engaging portion provided on the lower transport guide engages with an engaged portion provided on the housing, When the lower transport guide is rotated from a closed state to an open state relative to the main body of the document feeder, the engaging portion is disengaged from the engaged portion.

[0008] An image forming apparatus according to an embodiment of the present disclosure includes the document feeder. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to provide a document feeder and an image forming apparatus that can prevent document discharge failure even if the height of the document feeder is lowered and warping occurs. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view illustrating an appearance of an image forming apparatus according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view of a part of the image forming apparatus of FIG. [Figure 3] FIG. 3 is an enlarged view of area A in FIG. 2. [Figure 4] FIG. 3 is an enlarged perspective view of an area A in FIG. 2. [Figure 5] FIG. 10 is a diagram showing a state in which the lower transport guide has rotated. [Figure 6] FIG. 2 is a perspective view showing the appearance of a base tray. [Figure 7] FIG. [Figure 8] 10 is a cross-sectional view showing an engagement state between the base tray and the lower transport guide. FIG. [Figure 9] 10 is a cross-sectional view showing a disengaged state between the base tray and the lower transport guide. FIG. [Figure 10] FIG. 10 is a perspective view showing an engagement state between the base tray and the lower transport guide. [Figure 11] FIG. 4 is a perspective view showing a part of the lower transport guide. [Figure 12] 10A and 10B are schematic diagrams illustrating a state in which a document transport failure occurs due to warping of the base tray. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, identical or equivalent components are denoted by the same reference numerals, and redundant descriptions of identical or equivalent components will be omitted as appropriate.

[0012] Fig. 1 is a perspective view showing the appearance of an image forming apparatus 100 according to an embodiment of the present invention. In this embodiment, as shown in Fig. 1, the front side (front side or operation side) in the depth direction X of the image forming apparatus 100 is represented by the symbol X1, and the rear side (rear side or back side) is represented by the symbol X2. In the left-right direction Y, which is orthogonal to both the depth direction X and the up-down direction Z of the image forming apparatus 100, one side (the right side when viewed from the front side X1) is represented by the symbol Y1, and the other side (the left side when viewed from the front side X1) is represented by the symbol Y2. The upper side in the up-down direction Z is represented by the symbol Z1, and the lower side is represented by the symbol Z2.

[0013] Image forming apparatus 100 is a multifunction peripheral having multiple functions, such as a copy function, a scanner function, a facsimile function, and a printer function. For example, as shown in Fig. 1, image forming apparatus 100 includes a document feeder 200, an image forming apparatus main body 110, and a manual feed tray device 120. Image forming apparatus main body 110 includes an image reading device 111, a paper feeder 112, an image forming unit 113, and an ejection unit 114. Manual feed tray device 120 is provided on a side surface of image forming apparatus main body 110 (the side surface as viewed from front side X1) so as to be openable and closable.

[0014] The image reading device 111 reads an image of a document and has a document reading unit (scanner) not shown. The image reading device 111 reads an image of the document conveyed by the document reading unit while the document is conveyed by the document feeding device 200, or scans and reads a document placed on a document placing table of the document reading unit by the document reading unit.

[0015] The document feeder 200 is supported so as to be openable and closable relative to the image forming apparatus main body 110. Specifically, the document feeder 200 is configured so that the front side X1 of the document feeder 200 can be opened and closed around an axis extending in the left-right direction Y as a rotation axis at the rear side X2 of the upper side Z1 of the image forming apparatus main body 110. When the document feeder 200 of the image forming apparatus 100 is opened relative to the image forming apparatus main body 110, the document placing table is opened and a document can be placed thereon manually.

[0016] The paper feeder 112 stores sheets such as recording paper and supplies the stored sheets to the image forming unit 113. The paper feeder 112 supplies sheets of various sizes, with the center of the sheets in the width direction W perpendicular to the supply direction H as a reference (center reference). The image forming unit 113 forms (prints) an image on the sheets sent from the paper feeder 112. The image forming unit 113 forms an image based on image data of a document read by the image reading device 111, for example. The image forming unit 113 may have a known configuration and function. For example, the image forming unit 113 forms an image based on image data corresponding to a color image using each of the colors black (K), cyan (C), magenta (M), and yellow (Y), or a monochrome image using a single color (e.g., black). The image forming unit 113 is provided with four developing devices, photosensitive drums, drum cleaning devices, and chargers for forming four types of toner images, each corresponding to black, cyan, magenta, and yellow. These mechanisms enable the image forming unit 113 to form an image. The discharge unit 114 discharges the sheet on which the image has been formed by the image forming unit 113.

[0017] In this embodiment, the document feeder 200 includes a document placement tray 210 on which documents are placed, and a document size detection unit 220 disposed on the document placement tray 210 and detecting the size of the document placed on the document placement tray 210. The document feeder 200 supplies documents of each size with the center in a width direction W perpendicular to the supply direction H as a reference (center reference).

[0018] 2 is a cross-sectional view of the document feeder 200 when the image forming apparatus 100 in FIG. 1 is cut along the YZ plane. The document placing table is formed on the upper side Z1 of the image reading device 111. The document feeder 200 is disposed on the upper side Z1 of the document placing table.

[0019] The document feeder 200 includes a document supply unit 201 (for example, a pickup roller, not shown), a document transport unit 202, a document discharge unit 203 composed of a pair of discharge rollers including a drive roller 241a and a driven roller 241b, a transport guide 204, and a base tray 205 including a document stacking tray 300. The document supply unit 201 supplies documents placed on a document placement tray 210 to the document transport unit 202 one by one. The document transport unit 202 transports the documents supplied from the document supply unit 201 based on the center in the width direction W (see FIG. 1). The document discharge unit 203 discharges the documents transported by the document transport unit 202 onto the document stacking tray 300 of the base tray 205. The transport guide 204 transports the documents toward the base tray 205, which functions as a discharge tray. Specifically, the transport guide 204 forms a transport path for the documents, thereby guiding the documents discharged by the document discharge unit 203 onto the document stacking tray 300 of the base tray 205. In this embodiment, the transport guide 204 is composed of an upper transport guide 204a arranged on the upper side Z1 of the transport path and a lower transport guide 204b arranged on the lower side Z2 of the transport path. The base tray 205 is a housing that forms the base of the document feeder 200 and is arranged on the lower side Z2 of the document feeder 200.

[0020] The document supply unit 201 may have a known configuration. For example, the document supply unit 201 includes a pickup roller, a supply roller, a separation member (separation roller or separation pad), a supply drive transmission mechanism, and a support member. The pickup roller picks up the topmost document among the documents placed on the document placement tray 210. The supply roller and separation member separate and transport the documents picked up by the pickup roller one by one. The supply roller, together with the separation member, transports the documents picked up by the pickup roller one by one. The separation member is disposed opposite the supply roller. The separation member restricts the transport of the second and subsequent documents from the top among the documents placed on the document placement tray 210 in the transport direction H. The supply drive transmission mechanism is composed of a gear train or pulleys and a belt, and transmits the rotational drive force sent to the supply roller to the pickup roller. The pickup roller, supply roller, and separation member are located at the center in the width direction W. This allows the pick-up roller, supply roller, and separation member to pick up and supply the document based on the center reference in the width direction W. The pick-up roller and supply roller rotate under the control of a control unit (not shown). The document supply unit is a conventionally known unit, and other detailed configurations will not be described here.

[0021] The document transport unit 202 may have a known configuration. For example, the document transport unit 202 includes a transport guide, a transport roller pair, a registration roller pair, a pre-reading transport roller pair, a post-reading transport roller pair, and a pre-discharge transport roller pair, which form a document transport path. The transport roller pair, the registration roller pair, the pre-reading transport roller pair, the post-reading transport roller pair, and the pre-discharge transport roller pair are arranged in this order along the sheet transport path. The transport guide forms the document transport path between the document supply unit 201 and the document discharge unit 203. The transport path has a reading unit at the bottom that reads the image of the document. The transport roller pair, the registration roller pair, the pre-reading transport roller pair, the post-reading transport roller pair, and the pre-discharge transport roller pair are each composed of a drive roller and a driven roller. The drive roller rotates based on control by a control unit (not shown). The driven roller rotates in response to the rotation of the drive roller.

[0022] FIG. 3 is an enlarged view of region A in FIG. 2, and FIG. 4 is an enlarged perspective view of region A in FIG. 2. That is, FIG. 4 is a perspective view of the portion illustrated in FIG. 3. FIGS. 3 and 4 mainly illustrate the document discharge unit 203. The document discharge unit 203 includes a pair of discharge rollers 241. The pair of discharge rollers 241 is composed of a drive roller 241a and a driven roller 241b. The rotation shaft of the drive roller 241a is provided on the frame, not on the base tray 205. The rotation shaft of the driven roller 241b is provided on the lower transport guide 204b. The driven roller 241b is rotatably pressed against the drive roller by a biasing member (e.g., a spring) in the lower transport guide 204b. The drive roller 241a rotates by being driven by a drive means (e.g., a motor) under the control of a control unit (not shown). The driven roller 241b is rotated in response to the rotation of the drive roller 241a. The original document transported to the original discharge section 203 is transported along the transport path formed by the transport guide 204 toward the base tray 205 by the rotation of the drive roller 241a and the driven roller 241b, and is discharged onto the original stacking tray 300 of the base tray 205. The base tray 205 includes a wall section 206. Details of the wall section 206 will be described in detail later with reference to FIG. 6.

[0023] The upper transport guide 204a is fixed to the main body of the document feeder 200. The lower transport guide 204b is rotatably attached to the main body of the document feeder 200. In this embodiment, the lower transport guide 204b is rotatably supported on a side wall of the base tray 205 of the document feeder 200. Specifically, the left side Y2 of the lower transport guide 204b is attached so as to be rotatable in the downward direction Z2 direction, around an axis B that extends in the depth direction X on the right side Y1 of the lower transport guide 204b (see FIG. 5).

[0024] As described above, the document feeder 200 is supported so as to be openable and closable relative to the image forming apparatus main body 110. When the document feeder 200 is closed relative to the image forming apparatus main body 110 as shown in FIG. 1, the document tray of the image forming apparatus main body 110 is located below the document feeder 200 (Z2), and therefore the lower transport guide 204b cannot rotate relative to the main body of the document feeder 200. By opening the document feeder 200 relative to the image forming apparatus main body 110, the user can rotate the lower transport guide 204b, for example, if a document jams in the transport path. In other words, when the document feeder 200 is opened relative to the image forming apparatus main body 110, the lower transport guide 204b of the document feeder 200 is no longer in contact with the document tray, and a space is secured for the lower transport guide 204b to rotate. The lower transport guide 204b can rotate in the space thus formed.

[0025] 2 shows a state in which the lower transport guide 204b is closed relative to the main body of the document feeder 200. The closed state refers to a state in which the lower side Z2 of the document feeder 200 is covered by the lower transport guide 204b, and the inside of the document feeder 200 cannot be accessed from the outside. When the lower transport guide 204b is closed, the upper transport guide 204a and the lower transport guide 204b form a document transport path.

[0026] FIG. 5 is a diagram illustrating a state in which the lower transport guide 204b has rotated. FIG. 5 is a cross-sectional view of the document feeder 200 taken along the YZ plane, illustrating a state in which the lower transport guide 204b has rotated. The rotation axis B of the lower transport guide 204b when it rotates is different from the rotation axis of the driven roller 241b. In this embodiment, the rotation axis B is located to the right (Y1) of the rotation axis of the driven roller 241b. As shown in FIG. 5, when the lower transport guide 204b rotates from a closed state, the lower transport guide 204b is opened relative to the main body of the document feeder. The opened state refers to a state in which the rotation of the lower transport guide 204b allows access to the interior of the document feeder 200 from the outside. In other words, when the lower transport guide 204b is rotated as shown in FIG. 5, the user can access the interior of the document feeder 200. Therefore, for example, if a paper jam occurs inside the document feeder 200, the user can clear the paper jam by rotating the lower transport guide 204b and removing the paper inside the document feeder 200.

[0027] At least a portion of the base tray 205 functions as a discharge tray on which documents discharged by the document discharge unit 203 (i.e., documents whose images have been read) are stacked. FIG. 6 is a perspective view showing the exterior of the base tray 205. An opening 205a is formed in the base tray 205. As will be described in detail later, the base tray 205 engages with the lower transport guide 204b when the lower transport guide 204b is closed relative to the main body of the document feeder 200. The opening 205a is a space in which the lower transport guide 204b is disposed, and the lower transport guide 204b is configured to be rotatable downward Z2 in the opening 205a.

[0028] As shown in FIG. 6, the base tray 205 includes a wall portion 206 extending in the upward Z1 direction at the engagement point with the lower transport guide 204b. For example, the wall portion 206 is provided between the discharge roller and the document stacking tray in the document transport direction H. The wall portion 206 functions as a rib for improving strength. As shown in FIG. 6, the wall portion 206 is formed along the depth direction X. A notch portion 206a is formed by cutting out a portion of the wall portion 206. FIG. 6 is a partial enlarged view of the base tray 205, specifically, a view showing an enlarged view of the vicinity of the notch portion 206a. As shown in FIG. 7, the notch portion 206a does not include a member extending in the upward Z1 direction, or if there is a member, it is formed so that it is lower than the surrounding wall portion 206. The notch portion 206a is formed at the location where the driven roller 241b is located, as shown in FIG. 4, for example. That is, the notches 206a are formed to avoid interference with the driven rollers 241b. The notches 206a are formed in accordance with the number of driven rollers 241b. In this embodiment, two driven rollers 241b are arranged in the depth direction X, and therefore two notches 206a are formed in the wall portion 206 as shown in FIG. 6.

[0029] Next, the relationship between the base tray 205 and the lower transport guide 204b will be described. FIG. 8 is a cross-sectional view showing an engaged state between the base tray 205 and the lower transport guide 204b. The engaged state is a state in which the base tray 205 and the lower transport guide 204b are engaged, as shown in FIG. 2, for example. Therefore, in the engaged state, the lower transport guide 204b is closed relative to the main body of the document feeder 200. FIG. 9 is a cross-sectional view showing a disengaged state between the base tray 205 and the lower transport guide 204b. The disengaged state is a state in which the base tray 205 and the lower transport guide 204b are not engaged, as shown in FIG. 5, for example, i.e., a disengaged state. Therefore, in the disengaged state, the lower transport guide 204b is open relative to the main body of the document feeder 200. When the lower transport guide 204b is rotated, the base tray 205 and the lower transport guide 204b are disengaged. 8 and 9 are cross-sectional views of the document feeder 200 taken along the YZ plane, and are partially enlarged views showing only the engagement between the base tray 205 and the lower transport guide 204b. Fig. 10 is a perspective view showing the engagement between the base tray 205 and the lower transport guide 204b. Note that cross sections of some components are shown, and the cross sections are hatched.

[0030] As shown in FIGS. 8 to 10, the base tray 205 has a base tray engaging portion 207 (engaged portion) provided on the wall portion 206. In this embodiment, the base tray engaging portion 207 is formed from the upper side Z1 of the wall portion 206. Specifically, in this embodiment, the base tray engaging portion 207 includes a first flat portion 207a, a second flat portion 207b, and an inclined portion 207c. The first flat portion 207a is a flat surface formed at an end of the upper side Z1 of the wall portion 206. The second flat portion 207b is a flat surface formed at an end of the lower side Z2 of the first flat portion 207a on the side of the wall portion 206 where the lower conveying guide 204b is located (i.e., the left side Y2). The second flat portion 207b is located on the lower side Z2 of the first flat portion 207a. The inclined portion 207c is a member that connects the first flat portion 207a and the second flat portion 207b. The inclined portion 207c is formed between the first flat portion 207a and the second flat portion 207b.

[0031] As shown in FIGS. 8 to 10 , the transport lower guide 204b has a transport lower guide engaging portion 208 (engaging portion). In this embodiment, the transport lower guide engaging portion 208 is formed at a position where it can engage with the base tray engaging portion 207 in the engaged state, and is formed, for example, at the end of the right side Y1 of the transport lower guide 204b. Specifically, in this embodiment, the transport lower guide engaging portion 208 includes an upper engaging portion 208a and a lower engaging portion 208b. The upper engaging portion 208a engages with the first flat portion 207a in the engaged state. The lower engaging portion 208b engages with the second flat portion 207b in the engaged state. That is, the transport lower guide engaging portion 208 (engaging portion) engages with the base tray engaging portion 207 (engaged portion) from the upper and lower sides of the document feeding device 200. The upper engaging portion 208a and the lower engaging portion 208b may be configured in a shape that allows them to engage with the first flat portion 207a and the second flat portion 207b, respectively, in the engaged state.

[0032] FIG. 11 is a perspective view showing a portion of the lower transport guide 204b, specifically, a perspective view showing the lower transport guide engagement portion 208. In this embodiment, as shown in FIG. 11, the upper engagement portion 208a includes a protrusion 209 for engaging with the first flat portion 207a in the engaged state. The protrusion 209 can come into contact with the first flat portion 207a in the engaged state. In this embodiment, the lower engagement portion 208b has an L-shape in side view (YZ plane view) as shown in FIGS. 8 to 11. The bent tip portion 208b of the L-shaped lower transport guide engagement portion 208 extends along the left-right direction Y. The upper side Z1 surface (top surface) of the tip portion can come into contact with the second flat portion 207b in the engaged state. That is, in the engaged state, the upper engaging portion 208a and the lower engaging portion 208b of the lower transport guide 204b engage (grasp or sandwich) the base tray engaging portion 207 from above and below, thereby fixing the engaged state between the base tray 205 and the lower transport guide 204b. In this way, the lower transport guide engaging portion 208 (engaging portion) engages with the base tray engaging portion 207 (engaged portion) when the lower transport guide 204b is closed relative to the main body of the document feeder 200 (engaged state).

[0033] The height (length in the vertical direction Z) between the first flat portion 207a and the second flat portion 207b of the base tray engagement portion 207 and the distance (length) from the protrusion 209 of the lower conveying guide engagement portion 208 to the upper surface of the tip thereof are set to appropriate lengths that allow the lower conveying guide engagement portion 208 and the base tray engagement portion 207 to engage with each other. The difference between the height (length in the vertical direction Z) between the first flat portion 207a and the second flat portion 207b of the base tray engagement portion 207 and the distance (length) from the protrusion 209 of the lower conveying guide engagement portion 208 to the upper surface of the tip thereof is preferably small, and is preferably within 0.1 mm, for example. Thus, the smaller the clearance, the stronger the fixation state of the lower conveying guide 204b to the base tray 205 in the engaged state.

[0034] When the user opens the lower transport guide 204b relative to the main body of the document feeder 200, for example to clear a paper jam, the user rotates the left side Y2 of the lower transport guide 204b. At this time, the lower transport guide engagement portion 208 (engagement portion) is opened by rotating the lower transport guide 204b from a closed state relative to the main body of the document feeder 200, and the engagement with the base tray engagement portion 207 (engaged portion) is released. In other words, the lower transport guide engagement portion 208 and the base tray engagement portion 207 are in a disengaged state. Note that in the open state, even if the lower transport guide engagement portion 208 and the base tray engagement portion 207 are in a disengaged state, the document feeder 200 is stopped and does not transport documents, so there is no problem with the functionality of the device.

[0035] For example, after clearing a paper jam, the user rotates the left side Y2 of the transport lower guide 204b to close the transport lower guide 204b relative to the main body of the document feeder 200. At this time, the lower engagement portion 208b rotates from the lower side Z2 of the second flat portion 207b of the base tray engagement portion 207 (engaged portion) toward the second flat portion 207b. By engaging the transport lower guide engagement portion 208 (engaging portion) with the base tray engagement portion 207 (engaged portion), the transport lower guide 204b is closed.

[0036] Fig. 12 is a schematic diagram showing document transport failure due to warping of the base tray. Specifically, Fig. 12 is a simplified cross-sectional view of document feeder 200 cut along an XZ plane perpendicular to the left-right direction Y. In Fig. 12, the same components as those in the above embodiment are denoted by the same reference numerals. However, since Fig. 12 is a diagram for explaining the above embodiment and a comparative example in comparison, the components shown in Fig. 12 may not be completely identical to those in the above embodiment.

[0037] In the document feeder 200 according to the comparative example, for example, the height of the wall portion provided on the base tray 205 is lower than in the above embodiment, and therefore the strength of the base tray 205 is low, and therefore the document feeder 200 is prone to warping. The lower transport guide 204b is axially supported on the base tray 205 and is rotatably attached. In addition, the lower transport guide 204b is attached with a driven roller 241b that presses against the drive roller 241a. The driven roller 241b is in contact with the drive roller 241a with a predetermined pressure by a biasing member (for example, a spring).

[0038] For example, as shown by the dashed line in Figure 12, when the base tray 305 is bent downward, the side wall 305a of the base tray 305 falls inward (toward the center in the depth direction Z). As a result, the position of the hole 305b, which is provided in the side wall 305a of the base tray 305 and to which the lower transport guide 204b is attached, is lowered to the lower side Z2 than the position of the hole in an unwarped base tray 205. When the position of the hole 305b is lowered, the lower transport guide 204b moves away from the drive roller 241a, and the driven roller 241b attached to the lower transport guide 204b also moves away from the drive roller 241a. As a result, the pressure applied by the driven roller 241b against the drive roller 241a decreases, resulting in poor transport of the document. Furthermore, if the axial warpage of the base tray 305 differs, the pressure applied to the drive roller 241a by the driven roller 241b on the front side X1 differs from that of the driven roller 241b on the rear side X2, which can cause the document to skew.

[0039] In contrast, when the base tray 205 is lifted upward Z1 (i.e., when the warping of the base tray 205 is reduced to maintain the shape of the base tray 205), the side walls of the base tray 205 tilt from the inside (toward the center in the depth direction Z) to the outside (opposite the center in the depth direction Z), and the position of the hole for attaching the lower transport guide 204b of the base tray 205 rises. When the position of the hole rises, the lower transport guide 204b approaches the drive roller 241a, and the driven roller 241b attached to the lower transport guide 204b also approaches the drive roller 241a. As a result, the pressure of the driven roller 241b on the drive roller 241a approaches the design value, making it less likely that a document transport failure will occur.

[0040] 12, when the base tray 305 warps downward (arrow C), the side wall 305a tilts inward, and the position of the rotation axis of the lower transport guide 204b drops, so that the lower transport guide 204b drops relative to the drive roller 241a (arrow C). As a result, the position of the driven roller 241b attached to the lower transport guide 204b also drops relative to the drive roller 241a (arrow C). This reduces the pressure of the driven roller 241b against the drive roller 241a, which can cause document transport problems. On the other hand, when the base tray 205 is raised to reduce the warping of the base tray 205 (arrow D), the side wall tilts outward, and the position of the rotation axis of the lower transport guide 204b rises, so that the position of the lower transport guide 204b rises toward the drive roller 241a (arrow D). As a result, the position of the driven roller 241b attached to the lower transport guide 204b also rises toward the drive roller 241a (arrow D). As a result, the pressure of the driven roller 241b against the driving roller 241a approaches the design value, and the document transport failure is less likely to occur.

[0041] In the document feeder 200 described in the above embodiment, the lower transport guide 204b is provided with ribs for transporting the document, and the lower transport guide 204b is formed in a U-shape in cross section, so that the lower transport guide 204b is stronger than the base tray 205. The lower transport guide engaging portion 208 of the stronger lower transport guide 204b lifts up and engages with (grabs) the engaged portion (base tray engaging portion 207) provided on the wall portion 206 of the base tray 205, which has less strength, thereby reducing warping of the base tray 205. When the warping of the base tray 205 is reduced, the driven roller 241b approaches the drive roller 241a, so the pressure of the driven roller 241b against the drive roller 241a approaches the design value, making document transport problems less likely to occur. Furthermore, in the above embodiment, in the depth direction X, the lower transport guide engagement portion 208 grips the base tray engagement portion 207 at the center of two locations on the front side X1 and the rear side X2, so the difference in pressure on the drive roller 241a between the driven roller 241b on the front side X1 and the driven roller 241b on the rear side X2 becomes smaller between the front side X1 and the rear side X2, thereby making it less likely for the document to skew.

[0042] While the case where the base tray 205 is warped downward has been described above, the same applies to the case where the base tray 205 is warped upward. That is, when the center of the base tray 205 is aligned with the upper side, the side walls of the base tray 205 fall outward, causing the lower transport guide 204b and the driven roller 241b to move away from the drive roller 241a. This reduces the pressure exerted by the driven roller 241b against the drive roller 241a, resulting in poor document transport. Furthermore, when the center of the base tray 205 is warped upward, the non-engagement portion (base tray engagement portion 207) rises upward. In contrast, when the engagement portion is engaged with the engaged portion, the upper engagement portion 208a of the base guide 205 engages with the engaged portion along the inclined portion 207c of the engaged portion. During the engagement process, the engagement portion presses down the engaged portion, thereby pressing down the base tray 205.

[0043] In the document feeder 200 of the image forming apparatus 100 according to this embodiment, the lower transport guide engagement portion 208 engages with the base tray engagement portion 207 when the lower transport guide 204b is closed relative to the main body of the document feeder 200, and when the lower transport guide 204b rotates from the closed state to an open state relative to the main body of the document feeder 200, the engagement with the base tray engagement portion 207 is released.

[0044] The document feeder 200 of this embodiment has a simple structure in which, when the lower transport guide 204b is closed, the upper and lower transport guide engagement portions 208 of the lower transport guide 204b grip the engaged portion of the base tray 205 (base tray engagement portion 207).This allows the stronger lower transport guide 204b to lift the base tray 205 in a direction that reduces the warping of the base tray 205, thereby reducing the warping of the base tray 205 and bringing the pressure of the driven roller 241b on the drive roller 241a closer to the design value, making it less likely for document discharge problems to occur even if the unit height is low.

[0045] Furthermore, in the engaged state, the lower transport guide engagement portion 208 and the base tray engagement portion 207 are engaged with each other, thereby integrating the lower transport guide engagement portion 208 and the base tray engagement portion 207 at the engagement location. In other words, the two components can be integrated. This allows the base tray engagement portion 207 of the base tray 205 to be reinforced by the lower transport guide 204b by engaging with the stronger lower transport guide engagement portion 208, thereby improving the strength of the base tray 205, which is the paper ejection portion. Therefore, even if the height of the wall portion 206 functioning as a rib is lowered, the strength of the base tray 205 is not likely to decrease. Therefore, by lowering the height of the rib, the height of the entire document feeder can be lowered. In other words, the height of the document feeder 200 can be lowered while ensuring the paper stacking height in the base tray 205.

[0046] The base tray engaging portion 207 has an engaged portion (base tray engaging portion 207) provided on a wall portion adjacent to the discharge rollers that are subjected to a load when discharging a document. In this embodiment, the discharge rollers are provided at two locations in the depth direction X, and therefore the base tray engaging portions 207 are provided at two locations.

[0047] Furthermore, the base tray engaging portion 207 can be provided at an appropriate position on the wall portion 206. For example, the base tray engaging portion 207 can be provided across the center portion of the wall portion 206 (the center portion in the depth direction X in FIG. 6) excluding the cutout portion 206a. This makes it possible to easily lift up or press down areas with large warpage.

[0048] The base tray engagement portion 207 is preferably provided at least in a location that is weaker than other locations. For example, the notch portion 206a is weaker than other locations because the wall portion 206 is cut out. Therefore, the base tray engagement portion 207 is preferably provided near the notch portion 206a. The vicinity of the notch portion 206a refers to a predetermined range adjacent to the notch portion 206a in the wall portion 206. The extent of the predetermined range can be determined appropriately depending on, for example, the height of the wall portion 206 and the size of the notch portion 206a. The transport lower guide engagement portion 208 is provided at a position corresponding to the base tray engagement portion 207. That is, the transport lower guide engagement portion 208 is provided at a position in the depth direction X where the base tray engagement portion 207 is formed.

[0049] In the above embodiment, if the center of the base tray 205 warps downward, the engaged portion (base tray engaging portion 207) provided on the wall portion 206 will also warp downward from the position shown in Fig. 9. However, by setting the rotation center of the lower conveying guide 204b at the position shown in Figs. 9 and 5, the lower engaging portion 208b will grip (engage) the inclined portion 207c from below, so that the base tray 205 can be lifted. On the other hand, if the center of the base tray 205 is aligned with the upper side, the engaged portion (base tray engaging portion 207) provided on the wall portion 206 will also warp upward from the position shown in Fig. 9, but the upper engaging portion 208a will grip (engage) the inclined portion 207c from below, so that the base tray 205 can be pushed down.

[0050] Although the present disclosure has been described based on the drawings and embodiments, it should be noted that those skilled in the art can easily make various modifications and alterations based on the present disclosure. Therefore, it should be noted that these modifications and alterations are included in the scope of the present disclosure. For example, each feature can be rearranged so as not to be logically inconsistent, and multiple features can be combined or divided into one. [Explanation of symbols]

[0051] 100 Image forming device 110 Image forming device main body 111 Image reading device 112 Paper feeder 113 Image forming unit 114 Discharge section 120 Manual feed tray device 200 Document feeder 201 Manuscript Supply Department 202 Document transport unit 203 Original output section 204 Transport guide 204a Upper transport guide 204b Lower transport guide 205,305 Base tray 205a aperture 206 Wall section 206a Notch 207 Base tray engagement part 207a 1st plane part 207b 2nd plane part 207c slope section 208 Lower conveying guide engagement part 208a Upper engaging part 208b Lower engaging part 209 Protrusion 210 Document tray 220 Document size detection unit 241 Discharge roller pair 241a Drive roller 241b driven roller 300 Document tray 305a side wall

Claims

1. a transport guide for transporting the document; a pair of discharge rollers including a drive roller and a driven roller for discharging the transported document onto a document stacking tray; A document feeder comprising: the transport guide includes a transport lower guide pivotally supported on a housing including the document stacking tray, When the lower transport guide is closed relative to the main body of the document feeder, an engaging portion provided on the lower transport guide engages with an engaged portion provided on the housing, When the lower transport guide is rotated from a closed state to an open state relative to the main body of the document feeder, the engaging portion is disengaged from the engaged portion. Document feeder.

2. The document feeding device according to claim 1 , wherein the engaging portion engages with the engaged portion from above and below the document feeding device.

3. 2. The document feeder according to claim 1, wherein the driven roller is rotatably brought into pressure contact with the drive roller by a biasing member in the lower transport guide.

4. the engaged portion includes a first flat portion formed at an upper end portion, a second flat portion formed at an end portion below the first flat portion, and an inclined portion formed between the first flat portion and the second flat portion, the engaging portion includes an upper engaging portion that engages with the first flat surface portion and a lower engaging portion that engages with the second flat surface portion when the lower transport guide is closed relative to the main body of the document feeder. The document feeder according to claim 1 .

5. 5. The document feeding device according to claim 4, wherein when the lower transport guide is closed relative to the body of the document feeding device, the lower engaging portion rotates from below the second flat surface of the engaged portion toward the second flat surface.

6. a wall portion is provided in the housing between the discharge roller and the document stacking tray in a transport direction in which the document is transported; 2. The document feeder according to claim 1, wherein the wall portion has a notch formed at a location where the driven roller for discharging the document onto the document stacking tray is located.

7. The document feeder according to claim 6, wherein the engaged portion is provided at a location on the wall adjacent to the notch.

8. An image forming apparatus comprising the document feeder according to claim 1 .

Images