JP7438725B2 - Sheet conveyance device, image reading device, and image forming device - Google Patents

Description

The present invention relates to a sheet conveying device that conveys a sheet, an image reading device that reads image information from the sheet, and an image forming device that forms an image on a recording material.

2. Description of the Related Art Some image reading devices that read image information from a document are equipped with an automatic document feeder (hereinafter referred to as ADF) that feeds the document one sheet at a time. The ADF includes an opening/closing cover that can be opened and closed with respect to the ADF main body in order to facilitate the removal of documents stuck in the internal conveyance path and maintenance. Patent Document 1 describes a locking claw that keeps a cover member that can be opened and closed with respect to the main body of an ADF in a closed state by locking it to a locking pin of the main body.

Japanese Patent Application Publication No. 2008-131073

In the case of a configuration in which the opening/closing cover is provided with one roller of a pair of rollers, when the opening/closing cover is closed, the roller presses against the other roller to form a nip portion. At this time, if the opening/closing cover undergoes creep deformation or other deformation due to the stress acting on the opening/closing cover due to the nip pressure between the rollers, members such as rollers and guides provided on the opening/closing cover may become misaligned, resulting in sheet jams or poor conveyance. There is a concern that this may occur.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a sheet conveying device, an image reading device, and an image forming device that can suppress deformation of an openable cover.

One aspect of the present invention is a sheet conveying device that includes a main body and an openable cover that can be opened and closed with respect to the main body, and that conveys a sheet with the openable cover closed. a first roller provided, a support member supported by the opening/closing cover, a first shaft member supported by the support member and extending in the width direction of the sheet, and rotatably supported by the first shaft member, a second roller that is in pressure contact with the first roller when the opening/closing cover is closed and conveys the sheet in the sheet conveying direction together with the first roller; and a second shaft provided on the opening/closing cover and extending in the width direction. a biasing member that biases the second roller toward the first roller when the opening/closing cover is closed; and a biasing member provided on the second shaft member and provided on the main body portion. an engaging portion that holds the opening/closing cover in a closed state by engaging with the mating portion; and an engaging portion provided on the second shaft member that is attached to the upper surface of the opening/closing cover when the opening/closing cover is closed. a handle portion arranged so as to be exposed, the handle portion being used to perform an operation for releasing the engagement between the engaging portion and the engaged portion, the second shaft member and the supporting portion; The positions of the members in the sheet conveyance direction overlap , and the support member has a first region that supports the first shaft member and a portion of the handle portion that is located in the first region when viewed in the width direction. A second region that is allowed to protrude further downward than the second region .

According to the present invention, deformation of the opening/closing cover can be suppressed.

1 is a schematic diagram of an image forming apparatus according to an embodiment. FIG. 1 is a schematic diagram of an image reading device according to an embodiment. FIG. 1 is a block diagram showing a control configuration of an image reading device according to an embodiment. FIG. 3 is a diagram illustrating a state in which the cover unit of the document conveying device according to the embodiment is opened. FIG. 3(a) is a view of the inside of the cover unit according to the embodiment seen from above, and FIG. 3(b) is a side view of the cover unit. FIGS. 3A and 3B are diagrams (a, b) for explaining the support structure of the drawing roller according to the embodiment. FIG. 7 is a side view of a cover unit according to a modification.

Hereinafter, exemplary embodiments for carrying out the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram of an image forming apparatus 300 according to this embodiment. The image forming apparatus 300 includes an image forming section 250, an image reading section 200 disposed above the image forming section 250, and an auto document feeder (hereinafter referred to as ADF) supported by the image reading section 200. 80. The image forming section 250 forms an image on a sheet P used as a recording medium based on image information input from an external PC and image information read from a document by the image reading section 200. Sheets used as recording media or manuscripts include paper such as paper and envelopes, plastic films for overhead projectors, and cloth.

The image forming section 250 is a printing device having an intermediate transfer type electrophotographic unit 251 including four image forming stations PY, PM, PC, and PK, an intermediate transfer belt 231, and a fixing device 240. Each of the image forming stations PY to PK forms a toner image on the surface of the photosensitive drum 211 by an electrophotographic process. That is, when the electrophotographic unit 251 is requested to perform an image forming operation, the photosensitive drum 211, which is a photosensitive member, is rotationally driven in each of the image forming stations PY to PK, and the charging device charges the surface of the photosensitive drum 211. Charge uniformly. The exposure device 213 irradiates the photosensitive drum 211 with laser light based on image information to expose the drum surface and write an electrostatic latent image on the photosensitive drum 211. The developing device 214 supplies charged toner particles to the photosensitive drum 211 to develop the electrostatic latent image as a toner image. The toner images of each color formed by the image forming stations PY to PK are primarily transferred from the photosensitive drum 211 to the intermediate transfer belt 231 by the primary transfer roller 217 . Adherents such as toner remaining on the photosensitive drum 211 are removed by a drum cleaner 215.

The intermediate transfer belt 231, which is an intermediate transfer body, is wound around a secondary transfer inner roller 234, a tension roller 238, and a tension roller 232, and is rotated counterclockwise in the figure. The toner image carried on the intermediate transfer belt 231 is transferred to the sheet P at the secondary transfer portion T2, which is a nip portion between the intermediate transfer belt 231 and the secondary transfer roller 235 facing the secondary transfer inner roller 234. transcribed. Adherents such as toner remaining on the intermediate transfer belt 231 are removed by a belt cleaner 236.

The sheet P onto which the toner image has been transferred is delivered to the fixing device 240. The fixing device 240 includes a fixing roller 240a and a pressure roller 240b that sandwich and convey the sheet P, and a heat source such as a halogen heater that heats the fixing roller 240a. The fixing device 240 melts the toner by applying heat and pressure to the toner image while conveying the sheet P, and then the image is fixed on the sheet P by fixing the toner.

In parallel with such an image forming process, sheets P are fed one by one from the cassette 220. The sheet P sent out from the cassette 220 by the feeding roller 221, which is an example of a feeding member, is separated from other sheets by a separating member such as a separating roller or a separating pad, and is then fed through the drawing roller 224. transported. Thereafter, the pre-registration roller 222 abuts the leading edge of the sheet against the stopped registration roller 223, so that the skew of the sheet P is corrected. The registration roller 223 sends the sheet P to the secondary transfer section T2 at a timing that matches the progress of the image forming process by the electrophotographic unit 251. The sheet P on which the image has been formed by passing through the secondary transfer section T2 and the fixing device 240 is conveyed to the discharge roller 241 via conveyance rollers 242 and 243, and is transported to the discharge tray provided at the top of the image forming section 250. 249 is discharged.

In the above description, the electrophotographic unit 251 is an example of an image forming means, and may be an electrophotographic unit using a direct transfer method that directly transfers a toner image from a photoreceptor to the sheet P, or an image forming unit using an inkjet method or an offset printing method. A unit may also be used.

(Image reading device)
The ADF 80 and the image reading section 200 that constitute the image reading device of this embodiment will be explained using FIG. 2. The ADF 80 is a sheet conveyance device of this embodiment that conveys a sheet as a document.

The image reading section 200 includes a platen glass 18a, a document table glass 18b, and a reading unit 201. The reading unit 201 has a lamp 202 and a mirror 203, and is configured to be movable in the sub-scanning direction (horizontal direction in the figure) below the document platen glass 18b by being mounted on a carriage 204. The lamp 202 is a light source that irradiates the image surface of the document S with light. Reflected light from the original S is guided to an imaging lens 207 via mirrors 203, 205, and 206, and is imaged on a charge-coupled device 208 as an image sensor. The charge-coupled device 208 converts incident light into electronic image information by performing photoelectric conversion.

The reading unit 201 of the image reading section 200 can perform image reading operations in two modes: fixed reading and continuous reading. Fixed reading is an operation in which the reading unit 201 moves in the sub-scanning direction and reads image information from a stationary document placed on the document table glass 18b. Flow reading is an operation of reading image information from one sheet surface of a moving document transported by the ADF 80 with the reading unit 201 positioned below the platen glass 18a.

The ADF 80 includes a reading unit 24 , a document tray 11 , a feeding unit 143 , a pull-out roller 21 , transport rollers 22 , 23 , 25 , an ejection roller 16 , and an ejection tray 19 . The ADF 80 also includes a main body frame 144 that can be opened and closed with respect to the image reading section 200, and a cover unit 140 that can be opened and closed with respect to the main body frame 144. The detailed configuration of the cover unit 140 will be described later.

The reading unit 24 reads image information from the other sheet surface of the moving original transported by the ADF 80 via the platen glass 18c. That is, the reading unit 201 of the image reading section 200 and the reading unit 24 of the ADF 80 are both examples of reading means that read image information from a sheet. In this embodiment, a contact image sensor is used as the reading unit 24, and the reading unit 24 includes a lamp serving as a light source, a lens array forming an equal-magnification optical system, and an imaging device such as a CMOS.

A document S whose image is to be read is placed on the document tray 11, which is a sheet stacking section in this embodiment. The position of the document S placed on the document tray 11 in the width direction (main scanning direction) is regulated by a side regulating plate 10 that is movable in the width direction. Further, the lower surface of the document tray 11 is supported by a lift plate 145, which is an example of an elevating means. The lift plate 145 lifts up and lifts down the document tray 11 by being driven and rotated by a tray lift motor 181 (FIG. 3) that is a drive source.

The feeding unit 143 includes a feeding roller 1 , a conveyance roller 3 , and a separation roller 4 . The feeding roller 1 is supported by an arm 2 that is a holding member, and is arranged above the document tray 11. The arm 2 swings about the rotational axis of the transport roller 3, thereby allowing the feeding roller 1 to move up and down. The feeding roller 1 is a feeding member that feeds the originals S stacked on the original tray 11 to the left in the figure.

The ADF 80 includes a document set detection sensor 93 (FIG. 3) for detecting the presence or absence of a document S set on the document tray 11, and a feeding sensor 93 for detecting the top surface position of the document S loaded on the document tray 11. A position sensor 91 is provided. As the document set detection sensor 93, a photo interrupter that is shielded from light by a detection flag 100 (FIG. 2) that swings when the document S is set on the document tray 11 can be used. Further, as the feeding position sensor 91, a photointerrupter that is shielded from light by a flag section 90 provided on the arm 2 of the feeding unit 143 can be used.

The conveyance roller 3 is a conveyance member that receives the document S from the feed roller 1 and conveys it toward the pull-out roller 21 . The separation roller 4 is a roller connected to a fixed shaft via a torque limiter, and separates the document S by applying frictional force to the document S that has entered the separation nip between the transport roller 3 and the separation roller 4. do. When one document S enters the separation nip, the torque limiter slips and the separation roller 4 rotates as a result of the conveyance roller 3. On the other hand, when a plurality of documents enter the separation nip, the separation roller 4 does not rotate and stops the conveyance of sheets other than the uppermost sheet that is in contact with the conveyance roller 3.

The conveyance roller 3 and the separation roller 4 are separation and conveyance means of this embodiment that feeds the documents S stacked on the document tray 11 while separating them one by one. Note that the separation roller 4 is an example of a separation member, and a retard roller to which rotation in a direction opposite to sheet conveyance is input via a torque limiter or a pad-shaped friction member may also be used.

The pull-out roller 21 is arranged downstream of the separation nip in the conveyance direction of the document S. The pull-out roller 21 is a drive roller connected to a drive source, and conveys the document S by sandwiching it between the pull-out roller 304 that rotates with the pull-out roller 21 . A conveying roller 22 is arranged downstream of the pulling roller 21. The conveyance roller 22 is also a driving roller, and conveys the document S while sandwiching it between the conveyance roller 305 and the conveyance roller 305 that rotates with the conveyance roller 22 .

Conveyance rollers 23 and 25 and a discharge roller 16 are arranged downstream of the conveyance roller 22. The conveyance rollers 23 and 25 convey the original S through the scanning positions by the reading units 24 and 201. The discharge roller 16 is a discharge means for discharging the document S onto the discharge tray 19. Note that the ejection tray 19 is located below the document tray 11, and the direction in which the document is ejected by the ejection roller 16 (to the right in the figure) is different from the direction in which the document is fed by the feeding unit 143 (to the left in the figure). The directions are opposite with respect to the horizontal direction. Therefore, the document conveyance path inside the ADF 80 is curved in a U-shape when viewed from the front side of the image forming apparatus 300.

An overview of the operation of the ADF 11 will be explained. When the original S is inserted into the original tray 11, the detection flag 100 swings and blocks the optical axis of the original set detection sensor 93. Then, the control unit 50 (FIG. 3), which will be described later, determines that the original S has been set on the original tray 11.

When the user instructs the start of a reading operation via the operation unit of the image forming apparatus 300 with the original S set on the original tray 11, the control unit 50 starts the reading job in the flow reading mode. First, the lift plate 145 is driven to raise the document tray 11. Then, the upper surface of the originals S stacked on the original tray 11 comes into contact with the feeding roller 1, and the feeding roller 1 starts to rise. When the flag section 90 provided on the arm 2 of the feeding unit 143 blocks the optical axis of the feeding position sensor 91, the control section 50 further raises the document tray 11 by a predetermined distance using the lift plate 145, and then lifts the document tray 11 by a predetermined distance. Stop driving. As a result, the document S is raised to a height at which it can be fed by the feeding roller 1.

Next, by driving the feeding unit 143, the document S is sent out from the document tray 11 by the feeding roller 1, and is conveyed toward the pulling roller 21 by the conveying roller 3. At this time, the originals S are separated by the separation roller 4 so that the transport roller 3 transports the originals S one by one. Each time one document S reaches the nip between the pull-out roller 21 and the pull-out roller 304 (hereinafter referred to as the pull-out nip), the arm 2 rises and the feeding roller 1 separates from the upper surface of the document S.

The pulling roller 21 further transports the document S received from the transport roller 3. Here, the conveyance speed (peripheral speed) of the pull-out roller 21 is set to a larger value than the conveyance speed (circumferential speed) of the conveyance roller 3, and the pull-out roller 21 accelerates the document S to remove the document S from the separation nip. Transport it by pulling it out. Then, the document S is conveyed by conveyance rollers 22, 23, and 25 along a conveyance path curved in a U-shape. In the process, image information of the document S is read by one or both of the reading unit 24 and the reading unit 201 while passing between the platen glasses 18a and 18c. Thereafter, the document S is discharged onto the discharge tray 19 by the discharge roller 16.

Note that the reason why the conveyance speed of the pull-out roller 21 is set higher than the conveyance speed of the conveyance roller 3 is to improve the throughput of the ADF 80 while preventing double feeding of the documents S. That is, the conveyance speed of the conveyance roller 3 is set to be low enough to sufficiently separate the document S by the frictional force that the separation roller 4 applies to the document S. On the other hand, by setting the conveyance speed of the pull-out roller 21 (and the downstream conveyance roller 22, etc.) high, the number of documents that pass through the scanning positions of the reading units 24 and 201 per unit time is increased, and the throughput of the ADF 80 is increased. It can be improved.

(control system)
A configuration for controlling the ADF 80 will be described using FIG. 3. The control means for controlling the ADF 80 consists of a control circuit having at least one processor. The control unit 50, which is a control means of this embodiment, includes a central processing unit (CPU) 51, a read-only memory (ROM) 52, which is an example of a nonvolatile storage medium, and a random access memory (ROM), which is an example of a volatile storage medium. access memory (RAM) 53. The CPU 51 reads and executes a program stored in the ROM 52 or the like, and controls the operations of the ADF 80 and the image reading section 200. The RAM 53 serves as a work space when the CPU 51 executes a program. Note that each function of the control unit 50 described below may be implemented as independent hardware such as an ASIC on the circuit of the control unit, or may be implemented in software as a functional unit of a program executed by the CPU 51 or other processing device. It may be implemented in Further, the control unit 50 may be mounted outside the housing of the ADF 80 (for example, in the image reading unit 200).

The ADF 80 is provided with the above-described feeding position sensor 91, document set detection sensor 93, and double feed detection sensor 92 as various sensors for detecting the state of the apparatus. A double feed detection sensor 92 detects a double feed state in which a plurality of documents enter the separation nip. Specifically, the double feed detection sensor 92 includes a transmitter 92a that emits light that crosses the document transport path between the separation nip and the pull-out nip on the document transport path, and a receiver 92b that detects the light emitted by the transmitter 92a. and has. The control unit 50 determines that double feeding of originals has occurred when the receiving unit 92b continues not to detect light even after a predetermined timing after the current feeding of the original S is started. The predetermined timing represents the estimated time when the trailing edge of the current document S passes the optical axis position of the double feed detection sensor 92, and the predetermined timing represents the estimated time when the trailing edge of the current document S passes the optical axis position of the double feed detection sensor 92, and the time when the feeding start time of the current document S and the timing of the transport roller 3 and the pull-out roller 21. It can be determined based on the conveyance speed.

The CPU 51 controls the operation of each of the motors 181 to 183, which are the drive sources of the ADF 80, by sending a drive command to the driver 54. The tray lifting motor 181 drives the above-mentioned lift plate 145. The feeding motor 182 drives the feeding roller 1 and the conveyance roller 3 of the feeding unit 143. Note that the feed motor 182 may also be configured to drive the extraction roller 21 and the conveyance roller 22, or another motor that drives the extraction roller 21 and the conveyance roller 22 may be arranged.

The feed roller lift motor 183 can move the feed roller 1 between a position where it can come into contact with the originals stacked on the original tray 11 and a retracted position where it does not come into contact with the originals. The feeding roller lifting motor 183 is configured to drive, for example, a cam mechanism that swings the arm 2 of the feeding unit 143. In this embodiment, these motors 181 to 183 are stepping motors. The CPU 51 can control the rotation amount and rotation speed of the motors by specifying the number and frequency of excitation pulses that the driver 54 sends to each of the motors 181 to 183. Further, the driver 54 can also rotate each motor 181 to 183 in the opposite direction.

The control section 50 is connected to a main body control section 350 mounted on the image forming section 250 via a communication IC 59. The main body control section 350 includes a control circuit having at least one processor, and controls the image forming operation by the electrophotographic unit 251 and the conveying operation of the sheet P, which is a recording material. The main body control unit 350 receives image information read by the image reading device, and executes a job to form a copy image on the sheet P based on the image information. The main body control unit 350 also serves as a control unit that centrally controls the image forming apparatus 300, and for example, sends commands to the control unit 50 based on instructions given by the user via the operation unit to operate the image reading apparatus. control.

(Support structure of cover unit)
Next, the support structure of the cover unit 140, which is the opening/closing cover of this embodiment, will be explained in detail. FIG. 4 is a schematic diagram of the ADF 80 showing the cover unit 140 in an open state. Hereinafter, the term "original conveyance direction" refers to the direction in which the document is conveyed by the pull-out rollers 21 and the pull-out rollers 304, unless otherwise specified. The document conveyance direction is the sheet conveyance direction in this embodiment. The "main scanning direction" refers to the direction in which the reading units 24, 201 scan the original (direction perpendicular to the original transport direction). The main scanning direction is the width direction of the sheet conveyed by the ADF 80. Moreover, the "vertical direction" refers to the vertical direction in the state of FIG. 1 in which the image forming apparatus 300 is installed on a horizontal surface.

As shown in FIGS. 4 and 5(a), the cover unit 140 includes an exterior cover 307, an opening/closing guide 6, a pull-out support plate 306, and a conveyance support plate 308. Further, the above-mentioned feeding unit 143, extraction roller 304, conveyance roller 305, detection flag 100 of the document set detection sensor 93, and feeding position sensor 91 are provided in the cover unit 140.

The cover unit 140 is supported rotatably about a rotation center 146 with respect to a main body frame 144 that constitutes the main body of the ADF 80 . The cover unit 140 can be opened and closed between a closed state (closed position) as shown in FIG. 2 and an open state (open position) as shown in FIG.

The exterior cover 307 and the opening/closing guide 6 are fastened together with screws, and constitute a casing of the cover unit 140. The exterior cover 307 is a member that constitutes the upper exterior surface of the ADF 80. The opening/closing guide 6 is a guide member that faces the main body guide 36 supported by the main body frame 144, and forms a document transport path between the opening and closing guide 6 and the main body guide 36 when the cover unit 140 is closed. When the main body guide 36 is the first guide part of this embodiment, the opening/closing guide 6 is the second guide part of this embodiment.

The pull-out support plate 306 is supported by the casing of the cover unit 140 and supports the pull-out roller 304 via the pull-out roller shaft 309. Similarly, the conveyance support plate 308 is supported by the housing of the cover unit 140 and supports the conveyance rollers 305 via the conveyance roller shafts 310. Furthermore, there is a contact pressure (nip pressure) between the roller pair between the pull-out support plate 306 and the pull-out roller shaft 309 and between the conveyance support plate 308 and the conveyance roller shaft 310 when the cover unit 140 is closed. A pull-out spring 311 and a conveyance spring 312 are arranged, respectively, to generate the movement. The support structure of the drawing roller 304 will be explained in detail later.

When the pull-out roller 21 supported by the main body frame 144 is the first roller of this embodiment, the pull-out roller 304 is the second roller of this embodiment. Moreover, when the conveyance roller 22 supported by the main body frame 144 is the third roller of this embodiment, the conveyance roller 305 is the fourth roller of this embodiment. The pull-out support plate 306 is a support member of this embodiment, and the pull-out roller shaft 309 is a first shaft member of this embodiment.

Further, the cover unit 140 is provided with a handle 314 for opening and closing operations (see FIG. 5(b)), a handle shaft 301, and hooks 302, 302. The handle 314 is the handle portion of this embodiment, and the handle shaft 301 is the second shaft member of this embodiment. The handle 314 is integrally molded with the handle shaft 301 and is disposed in an opening provided in the exterior cover 307 when viewed from above. The handle 314 is exposed on the top surface of the cover unit 140, and as shown in FIG. 5(b), it is arranged so as to be substantially flush with the exterior cover 307 when it is not operated.

The handle shaft 301 extends along the main scanning direction (that is, in the width direction) to both outsides of the passage range through which the document passes in the main scanning direction. In particular, the handle shaft 301 of this embodiment penetrates outside the side wall portions on both sides of the cover unit 140 in the main scanning direction. Hooks 302, 302 are attached to both ends of the handle shaft 301 in the main scanning direction by, for example, a light press-fitting method. The handle shaft 301 is fitted into a hole provided in the casing of the cover unit 140 and rotates together with the handle 314 and the hooks 302, 302.

By rotating around the handle shaft 301, the hooks 302, 302 engage with and disengage from a latch shaft 303, which is an engaged portion provided on the main body frame 144. The hooks 302, 302 are both examples of engaging parts, and when one hook 302 is the first engaging member of this embodiment, the other hook 302 is the second engaging member of this embodiment. .

When opening the cover unit 140 in the closed state as shown in FIG. 2, the user operates the handle 314 from the state shown in FIG. 5(b) to pull it counterclockwise in the figure. Then, the handle shaft 301 and the hooks 302, 302 rotate in the same direction, and the hooks 302, 302 separate from the latch shafts 303, 303. As a result, the engagement between the cover unit 140 and the main body frame 144 via the hooks 302, 302 is released.

In this state, when the user further presses the handle 314 upward, the cover unit 140 rotates in the opening direction (counterclockwise in FIG. 2) about the rotation center 146 as a fulcrum. Thereby, the cover unit 140 is in an open state with respect to the main body frame 144, as shown in FIG.

When closing the open cover unit 140, the user operates the handle 314 or the exterior cover 307 to move the cover unit 140 in the closing direction (clockwise in FIG. 4) about the rotation center 146. Rotate. Then, the conveyance roller 3, the pull-out roller 304, and the conveyance roller 305 begin to come into pressure contact with the separation roller 4, the pull-out roller 21, and the conveyance roller 22, respectively (see FIG. 2). At this time, in the cover unit 140, the conveyance roller 3, the pull-out roller 304, and the conveyance roller 305 begin to receive an upward reaction force from the separation roller 4, the pull-out roller 21, and the conveyance roller 22.

When the cover unit 140 is further rotated, the hook 302 is caught on the latch shaft 303, thereby locking the cover unit 140 in the closed state. At this time, the cover unit 140 continues to receive the above-mentioned upward reaction force, but since the hook 302 is engaged with the latch shaft 303, rotation of the cover unit 140 in the opening direction is restricted.

Note that the opening and closing operations of the cover unit 140 are performed during maintenance or when a document jam occurs. In this case, when the user opens the cover unit 140, the posture of the cover unit 140 is maintained at a predetermined angle by a stopper (not shown), and the user can remove his/her hand from the cover unit 140 and perform the necessary work. It can be carried out. Further, the feeding unit 143 having the feeding roller 1 and the conveying roller 3 is configured to be detachable from the cover unit 140, so that necessary operations can be performed. For example, the feeding roller 1 or the conveying roller 3 can be replaced with the feeding unit 143 removed from the cover unit 140. Further, by removing the screws that fasten the opening/closing guide 6 to the exterior cover 307 serving as an exterior surface and removing the exterior cover 307, it is possible to access the components inside the opening/closing guide 6.

(Internal configuration of cover unit)
The detailed configuration of the cover unit 140 will be explained. FIG. 5(a) is a diagram of the inside of the cover unit 140 viewed from above. FIG. 5(b) is a cross-sectional view of the cover unit 140 viewed from the front side of the image forming apparatus 300 at the cross-sectional position indicated by line AA in FIG. 5(a). Note that FIG. 5A shows the cover unit 140 with the exterior cover 307 removed.

As shown in FIG. 5A, the opening/closing guide 6 of this embodiment supports four rotating bodies (rollers): a feeding roller 1, a conveying roller 3, a pulling roller 304, and a conveying roller 305. The four rotating bodies are arranged symmetrically with respect to the conveyance center C0 (the center position in the main scanning direction D2 of the document position determined by the side regulating plate 10 of the document tray 11) when the ADF 80 conveys the document. This symmetrical arrangement of the rotating bodies that apply conveying force to the document suppresses the rotation of the document during conveyance and prevents the document from being skewed, which in turn improves the stability of the conveyance operation and improves the accuracy of image information reading. It is possible to improve the In the illustrated example, one feeding roller 1, one conveying roller 3, and one pulling roller 304 are arranged on the conveying center C0, and a plurality of conveying rollers 305 are arranged symmetrically with respect to the conveying center C0. The number and arrangement of rotating bodies can be changed as appropriate.

First, the configuration regarding the feeding roller 1 and the conveying roller 3 that constitute the feeding unit 143 will be explained. The feeding roller 1 and the conveying roller 3 are rotatably held by the arm 2 via shafts 13 and 5, respectively. The arm 2 swings about the shaft 13 of the conveyance roller 3 as a fulcrum. The feeding roller 1 and the conveying roller 3 are connected via a timing belt 7 and rotate integrally.

The shaft 5 of the conveyance roller 3 is connected to a drive input shaft 150 via a drive coupling 151. The feeding unit 143 is held by the opening/closing guide 6 by a drive coupling 151 and a holder (not shown). A drive input gear 149 is attached to the drive input shaft 150. The drive input gear 149 is arranged to mesh with a drive output gear supported by the main body frame 144 and connected to the feed motor 182 (FIG. 3) when the cover unit 140 is closed. Therefore, when the feed motor 182 rotates with the cover unit 140 closed, the driving force is transmitted to the feed unit 143 via the drive input gear 149 and the drive coupling 151, and the drive force is transmitted to the feed roller 1 and the conveyance roller 3. rotates.

The arm 2 of the feeding unit 143 is provided with the flag portion 90 described above. Further, the opening/closing guide 6 is provided with the above-mentioned feeding position sensor 91 which is a photo interrupter. When the document tray 11 is lifted up at the start of continuous reading, the flag section 90 is raised by being pressed by the upper surface of the documents stacked on the document tray 11 and the feeding roller 1 is raised. Then, the control unit 50 can detect the heights of the document and the feeding roller 1 based on the flag unit 90 switching the detection state of the feeding position sensor 91 from, for example, a non-light-blocking state to a light-blocking state.

Next, the configuration regarding the drawing rollers 304 and the conveying rollers 305 will be explained. As shown in FIG. 5A, the pull-out roller 304 is arranged downstream of the conveyance roller 3 in the document conveyance direction D1, and the conveyance roller 305 is further arranged downstream of the pull-out roller 304. The extraction rollers 304 are rotatably attached to the extraction roller shaft 309, and the conveying rollers 305 are rotatably attached to the conveying roller shaft 310.

The extraction roller shaft 309 extends below the extraction support plate 306 in the main scanning direction D2. The drawing roller shaft 309 is supported by a drawing support plate 306 so as to be movable within a predetermined range in the direction of approaching and separating from the drawing roller 21 (vertical direction in FIG. 5(b)). The pull-out support plate 306 is a plate-shaped member that extends in the document conveyance direction D1 and the main scanning direction D2, and has a length that includes the passage range of the document in the main scanning direction D2. A pull-out spring 311, which is an elastic body of this embodiment, is arranged between the pull-out roller shaft 309 and the pull-out support plate 306. As the extraction spring 311, for example, a compression coil spring arranged such that the vertical direction is the direction of expansion and contraction can be used.

The pull-out spring 311 is arranged to be deformed by a predetermined amount of deformation from its natural length when the pull-out roller 304 comes into pressure contact with the pull-out roller 21 when the cover unit 140 is closed. Therefore, the contact pressure (nip pressure) generated between the pull-out roller 304 and the pull-out roller 21 is defined by the spring constant of the pull-out spring 311 and the amount of deformation of the pull-out spring 311 when the cover unit 140 is closed. .

Here, when the cover unit 140 is closed, the magnitude of the force with which the pull-out roller 304 and the pull-out roller 21 press against each other in the pull-out nip is the force with which the conveyance roller 3 and the separation roller 4 press against each other in the separation nip. is set larger than the size of . However, the magnitude of the force with which the rollers press against each other in the nip portion refers to the value obtained by integrating the contact pressure over the entire contact area between the rollers. This is so that the pulling roller 21 and the pulling roller 304 accelerate the document received from the conveying roller 3 and convey it by pulling it out from the separation nip.

The conveyance roller shaft 310 extends below the conveyance support plate 308 in the main scanning direction D2. The conveyance roller shaft 310 is supported by a conveyance support plate 308 so as to be movable within a predetermined range in directions toward and away from the conveyance roller 22 . The conveyance support plate 308 is a plate-shaped member that extends in the direction in which the document is conveyed by the conveyance roller 22 and in the main scanning direction D2, and has a length that includes the passage range of the document in the main scanning direction D2. A conveyance spring 312, which is another elastic body, is arranged between the conveyance roller shaft 310 and the conveyance support plate 308. Therefore, the contact pressure generated between the conveyance roller 305 and the conveyance roller 22 is defined by the spring constant of the conveyance spring 312 and the amount of deformation of the conveyance spring 312 when the cover unit 140 is closed.

FIGS. 6A and 6B show a structure in which the pull-out support plate 306 is supported by the opening/closing guide 6. FIG. 6A is a perspective view of how one end of the pull-out support plate 306 in the main scanning direction is supported by the opening/closing guide 6 when viewed from the front side of the image forming apparatus 300. FIG. 6B is a perspective view of how the other end of the pull-out support plate 306 in the main scanning direction is supported by the opening/closing guide 6 when viewed from the rear side of the image forming apparatus 300.

A front insertion portion 315 (FIG. 6(a)) is provided at one end of the pull-out support plate 306, and a back insertion portion 317 (FIG. 6(b)) is provided at the other end of the pull-out support plate 306. ) is provided. The front insertion portion 315 is constituted by a first protrusion 315a and a second protrusion 315b that respectively protrude toward one side in the main scanning direction D2. Similarly, the back side insertion part 317 is constituted by a first protrusion 317a and a second protrusion 317b that respectively protrude toward the other side in the main scanning direction D2.

The opening/closing guide 6 constituting the housing of the cover unit 140 is provided with a front opening 316 (FIG. 6(a)) into which the front insertion part 315 is inserted, and a back opening 318 into which the back insertion part 317 is inserted. It is being The front opening 316 and the back opening 318 are formed in the front wall 6f and the rear wall 6r of the opening/closing guide 6, which are bent from the guide surface forming the document conveyance path and extend substantially perpendicularly to the main scanning direction D2. It's a hole. Each of the front opening 316 and the back opening 318 includes first openings 316a, 318a into which the first projections 315a, 317a are inserted, and second openings 316b, 318b into which the second projections 315b, 317b are inserted. include.

As described above, since the pull-out spring 311 is disposed between the pull-out support plate 306 and the pull-out roller shaft 309 below the pull-out support plate 306, the pull-out support plate 306 receives an upward biasing force from the pull-out spring 311. When the cover unit 140 is closed, the pull-out spring 311 is compressed compared to when it is open, so the pull-out support plate 306 is urged upward in the figure with a stronger force. Therefore, the upper wall surfaces 316c, 316d, 318c, and 318d of the front opening 316 and the back opening 318 act as contact surfaces for receiving the pull-out support plate 306 by coming into contact with the front insertion portion 315 and the back insertion portion 317. Function. The pull-out support plate 306 is fixed to the opening/closing guide 6 with screws 319 in a state where the front insertion part 315 and the rear insertion part 317 are positioned so as to abut against the wall surfaces 316c, 316d, 318c, and 318d.

Here, the handle shaft 301 provided with the above-mentioned hook 302 is inserted into grooves 6g, 6g which are openings provided in the front wall 6f and rear wall 6r of the opening/closing guide 6. The position of the handle shaft 301 in the document transport direction D1 overlaps the position of the pull-out support plate 306 in the document transport direction D1. Further, the engagement position of the hook 302 and the latch shaft 303 in the document conveyance direction D1 also overlaps with the position of the pull-out support plate 306 in the document conveyance direction D1. However, when the positions of two members in a certain direction overlap, when the two members are projected onto a coordinate axis extending in that direction, at least part of the projected range (occupied range in that direction) of one member is the same as that of the other member. This refers to overlapping with the projection range of the member.

In this way, by overlapping the position of the handle shaft 301 provided with the hook 302 in the document conveyance direction D1 and the position of the pull-out support plate 306 in the document conveyance direction D1, the cover unit 140 can be suppressed from deformation. That is, the position of the pull-out support plate 306, which is urged upward by the urging force of the pull-out spring 311 that generates nip pressure, and the position of the handle shaft 301, which is locked to the main body frame 144 via the hook 302, overlap. are doing. In other words, when the cover unit 140 is closed, the position of the pull-out support plate 306, which is the acting part of the force acting upward on the cover unit 140, and the effect of the force acting downward on the cover unit 140. The position of the handle shaft 301, which is the part, overlaps with that of the handle shaft 301.

Therefore, deflection of the cover unit 140 in the document transport direction D1 (deformation in which a portion of the cover unit 140 rotates about the latch shaft 303 when viewed from the main scanning direction) can be suppressed. For example, since the bending of the opening/closing guide 6 is suppressed, the deviation in the distance between the opening/closing guide 6 and the main body guide 36 (FIG. 4) is reduced, contributing to improving the stability of document conveyance. Further, reducing the positional deviation of other rotating bodies (for example, the conveyance roller 3 and the conveyance roller 305) provided in the cover unit 140 also contributes to improving the stability of document conveyance. Furthermore, the positional deviation of the sensor (for example, the feeding position sensor 91) provided in the cover unit 140 is also reduced, which contributes to improving the detection accuracy of the top surface position of the document.

To explain in more detail, the first protrusions 315a and 317a of the front insertion part 315 and the rear insertion part 317 shown in FIGS. 6A and 6B are located upstream of the latch shaft 303 (FIG. 4) in the document conveyance direction D1. . Further, the second protrusions 315b and 317b are located downstream of the latch shaft 303 in the document conveyance direction D1.

In other words, the pull-out support plate 306 abuts against the opening/closing guide 6 at at least two locations in the document conveyance direction D1, and these abutting areas have a positional relationship in which the handle shaft 301 and the latch shaft 30 are sandwiched in the document conveyance direction D1. It has become. In other words, the opening/closing guide 6 is urged upward by the wall surfaces 316c and 318c as the first contact portions and the wall surfaces 316d and 318d as the second contact portions when the cover unit 140 is closed. It is configured to receive the pull-out support plate 306.

In this configuration, the upward biasing force by the pull-out spring 311 is transmitted to the opening/closing guide 6 via the first protrusions 315a, 317a and the second protrusions 315b, 317b of the front insertion part 315 and the rear insertion part 317. At this time, an upward force is applied symmetrically to the latch shaft 303, which is the fulcrum that supports the opening/closing guide 6, so the rotational moments relative to the latch shaft 303 cancel each other out, and the cover unit 140 uses the latch shaft 303 as the fulcrum. Deformation such as rotation can be more effectively suppressed.

Further, in this embodiment, the abutting positions of the front insertion portion 315 and the front opening 316 and the front hook 302 (FIG. 6(a)) are close to each other in the main scanning direction D2. Similarly, the abutment positions of the back side insertion portion 317 and the back side opening 318 and the front hook 302 (FIG. 6(b)) are close to each other in the main scanning direction D2. The front opening 316 and the back opening 318 are formed on the front wall 6f and the rear wall 6r of the opening/closing guide 6, and the hooks 302, 302 are formed on the outside of the front wall 6f and the rear wall 6r in the main scanning direction D2. It is located at a position facing the front side wall 6f and the rear side wall 6r in the main scanning direction D2.

As described above, since the engagement position of the hook 302 and the latch shaft 303 and the abutment position of the pull-out support plate 306 against the opening/closing guide 6 are close to each other in the main scanning direction D2, the cover unit 140 is moved in the main scanning direction D2. Deflection is also suppressed. That is, if the position where the pull-out support plate 306 abuts against the opening/closing guide 6 is provided only at the center in the main scanning direction D2, the opening/closing guide 6 would be stuck at both ends in the main scanning direction D2 where the opening/closing guide 6 is latched to the latch shaft 303. The central part is more likely to deform so that it protrudes upward than the other parts. On the other hand, by adopting the arrangement of this embodiment, deformation of the opening/closing guide 6 can be further reduced.

(Positional relationship between handle shaft and pull-out support plate)
Here, when the engagement position of the cover unit 140 with respect to the main body frame 144 and the pull-out support plate 306 that receives the biasing force of the pull-out spring 311 are arranged so that their positions in the document conveyance direction D1 overlap as described above, the grip shaft The arrangement of the handle 301 and the handle 314 may be an issue.

Therefore, in this embodiment, the handle shaft 301 is arranged above the pull-out support plate 306 as shown in FIGS. There is. The recessed portion 313 is provided at a position that does not overlap the drawing roller 304 in the main scanning direction D2 (outside the position of the drawing roller 304 in the main scanning direction D2).

The positional relationship between the recess 313 of the pull-out support plate 306 and the handle 314 will be described in detail. As shown in FIGS. 5(a, b), the recess 313 has a concave shape that is recessed downward compared to a portion 306a (first region) where the pull-out support plate 306 overlaps the pull-out spring 311 when viewed from above. The lower part of 314 is accommodated in the recess 313 . In other words, the pull-out support plate 306 is provided with a recess 313 as a second area that is recessed downward compared to the first area that supports the pull-out roller shaft 309, and a portion of the handle 314 is lower than the first area. It is configured to allow it to protrude downward.

Since the drawing support plate 306 of this embodiment is a steel plate, the recess 313 is formed by drawing. Although drawing is used in this embodiment to maintain strength, a notch or a through hole may be formed in the drawing support plate 306 as the second region.

As shown in FIG. 5B, the position of the recess 313 in the vertical direction overlaps with the upper part of the extraction roller 304, but since the recess 313 is separated from the extraction roller 304 in the main scanning direction D2, the recess 313 does not interfere with the drawing rollers 304. For the same reason, the recess 313 does not interfere with the extraction spring 311 or the extraction roller shaft 309. By arranging it in this way, as shown as a modification example in FIG. The cover unit 140 can be made thinner.

Furthermore, in this embodiment, the drawing support plate 306 and the handle 314 are configured so that their positions in the document transport direction D1 overlap, so that the drawing roller 21 and the drawing roller 304 can be brought close to the transport roller 3 and the separating roller 4. became possible. That is, considering a configuration in which the pull-out support plate 306 is moved downstream of the handle 314 in the document conveyance direction D1 in order to avoid interference between the handle 314 and the pull-out support plate 306, the pull-out roller 304 becomes smaller than in this embodiment. The document is moved downstream in the document transport direction D1. Here, since the conveyance speed of the extraction roller 21 is set higher than the conveyance speed of the conveyance roller 3, the longer the distance from the conveyance roller 3 to the extraction roller 21 becomes, the more disadvantageous it becomes in terms of the throughput of the ADF 80. In this embodiment, the throughput of the ADF 80 is improved by arranging the pull-out roller 21 and the pull-out roller 304 close to the conveyance roller 3 and separation roller 4 as shown in FIG. 5(a).

Note that, as shown in FIG. 7, as long as the positions of the pull-out support plate 306 and the handle 314 in the document transport direction D1 overlap, the handle 314 may be arranged to protrude above the exterior cover 307. . Although this modification has a larger thickness in the vertical direction than the above embodiment, it is possible to achieve a throughput equivalent to that of the embodiment.

(Modified example)
In this embodiment, the handle 314, the hook 302, and the handle shaft 301 are integrated. The latch shaft 303 may be detached from the latch shaft 303 when the latch shaft 303 is moved. Further, the hook-shaped hook 302 and the shaft-shaped latch shaft 303 are examples of an engaging part and an engaged part, and close the cover unit 140 against the contact pressure between rollers in a drawing nip or the like. Other configurations may be adopted for the engaging portion and the engaged portion as long as the configuration can be locked in the state. For example, a magnet may be used as the engaging portion and an iron plate may be used as the engaged portion.

Further, in this embodiment, a configuration is illustrated in which the pull-out spring 311 as an elastic body is provided on the cover unit 140 side, but a configuration in which the pull-out spring 311 biases the pull-out roller 21 upward on the main body side may also be used. good. Alternatively, the drawing spring 311 may be omitted, and the nip pressure may be generated by the elasticity of the rubber layer forming the outer peripheral portion of the drawing roller 21 and/or the drawing roller 304. In any of these cases, deformation of the cover unit 140 can be suppressed by employing the above-described arrangement of the pull-out support plate 306, the handle shaft 301, the handle 314, and the like.

(Other embodiments)
In the above embodiment, the configuration of the ADF 80 as an image reading device installed on the upper part of the image forming apparatus and a sheet conveying device forming a part of the image reading device has been described. However, the present technology is also applicable to other image reading devices or sheet conveying devices. An example is a sheet conveying device that conveys a sheet used as a recording material in an image forming apparatus. Further, the present technology may be applied not only to the field of image forming apparatuses but also to sheet conveyance devices for conveying flyers and mail, for example.

3...Conveyance roller/4...Separation member (separation roller)/6...Second guide section (opening/closing guide)/11...Sheet stacking section (document tray)/21...First roller (pulling roller)/22...Third roller (Conveyance roller)/24, 201...Reading means (reading unit)/36...First guide section (main body guide)/80...Sheet conveyance device (ADF)/90...Flag section/91...Sensor (feeding position sensor) /140...opening/closing cover (cover unit)/251...image forming means (electrophotographic unit)/300...image forming apparatus/301...second shaft member (handle shaft)/302...engaging portion (hook)/303...cover Engagement part (latch shaft) / 304... Second roller (pulling roller) / 305... Fourth roller (conveying roller) / 306... Support member (pulling support plate) / 306a... First region / 309... First shaft member (Pull-out roller shaft) /311...Elastic body (pull-out spring)/313...Second region (recess)/314...Handle part (handle)/316c, 318c...First contact part (wall surface)/316d, 318d...No. 2 Contact part (wall surface)

Claims (17)

A sheet conveying device comprising a main body and an open/close cover that can be opened and closed with respect to the main body, and conveys a sheet with the open/close cover closed,
a first roller provided in the main body;
a support member supported by the opening/closing cover;
a first shaft member supported by the support member and extending in the width direction of the seat;
a second roller that is rotatably supported by the first shaft member, presses against the first roller when the opening/closing cover is closed, and conveys the sheet in the sheet conveying direction together with the first roller;
a second shaft member provided on the opening/closing cover and extending in the width direction;
a biasing member that biases the second roller toward the first roller when the opening/closing cover is closed;
an engaging part provided on the second shaft member and holding the opening/closing cover in a closed state by engaging with an engaged part provided on the main body part;
a handle provided on the second shaft member and arranged so as to be exposed on the upper surface of the opening/closing cover when the opening/closing cover is closed; a handle for performing an operation to release the
The positions of the second shaft member and the support member in the sheet conveyance direction overlap ,
The support member includes a first region that supports the first shaft member, and a second region that allows a portion of the handle portion to protrude below the first region when viewed in the width direction. and has
A sheet conveying device characterized by: a sheet stacking section on which sheets are stacked;
a conveyance roller that conveys the sheet fed from the sheet stacking section toward the first roller and the second roller;
further comprising a separating member that comes into contact with the conveyance roller and separates the sheets conveyed by the conveyance roller one by one,
The conveyance speed of the first roller and the second roller is set higher than the conveyance speed of the conveyance roller.
The sheet conveying device according to claim 1, characterized in that: When the opening/closing cover is closed, the force with which the first roller and the second roller press against each other is greater than the force with which the conveyance roller and the separation member press against each other.
The sheet conveying device according to claim 2, characterized in that: a flag part that moves according to the position of the top surface of the sheets stacked on the sheet stacking part;
a sensor provided on the opening/closing cover and detecting the flag portion;
The sheet conveying device according to claim 2 or 3, characterized in that: the biasing member is disposed between the support member and the first shaft member;
The sheet conveying device according to any one of claims 1 to 4, characterized in that: The opening/closing cover has a first contact portion that contacts the support member upstream of the second shaft member in the sheet transport direction, and a first contact portion that contacts the support member downstream of the second shaft member in the sheet transport direction. a second abutting part, the support member being urged by the urging member when the opening/closing cover is closed is received by the first abutting part and the second abutting part;
The sheet conveying device according to claim 5, characterized in that: the position of the biasing member in the sheet conveyance direction and the engagement position of the engaging portion and the engaged portion in the sheet conveyance direction overlap;
The sheet conveying device according to claim 5 or 6, characterized in that: The position of the first shaft member in the sheet transport direction overlaps the position of the second shaft member in the sheet transport direction,
The first shaft member is arranged below the support member, and the second shaft member is arranged above the support member.
The sheet conveying device according to any one of claims 1 to 7. The handle portion is disposed outside the second roller in the width direction .
The sheet conveying device according to any one of claims 1 to 8 . The second region has a concave shape in which a part of the support member is recessed downward compared to the first region.
The sheet conveying device according to any one of claims 1 to 9 . The second region has an opening shape provided in the support member,
The sheet conveying device according to any one of claims 1 to 9 . The support member is a plate-shaped member extending in the sheet conveyance direction and the width direction, and has at least one end in the width direction fixed to the opening/closing cover.
The sheet conveying device according to any one of claims 1 to 11 . a first guide part provided in the main body part;
a second guide part provided on the opening/closing cover, facing the first guide part when the opening/closing cover is closed, and forming a sheet conveyance path between the second guide part and the first guide part;
The sheet conveying device according to any one of claims 1 to 12 . The opening/closing cover has an exterior cover that constitutes an exterior surface of the sheet conveying device,
The second guide part and the exterior cover are fixed to each other and form a housing of the opening/closing cover,
the support member is attached to the casing;
The sheet conveying device according to claim 13 , characterized in that: a third roller provided in the main body portion and located downstream of the first roller with respect to the sheet conveyance direction;
a fourth roller that is provided on the opening/closing cover, contacts the third roller when the opening/closing cover is closed, and pinches and conveys the sheet together with the third roller;
The sheet conveying device according to any one of claims 1 to 14 . The sheet conveying device according to any one of claims 1 to 15 ,
reading means for reading image information from the sheet conveyed by the sheet conveyance device;
An image reading device characterized by: An image reading device according to claim 16 ;
an image forming unit that forms an image on a recording material based on image information read by the image reading device;
An image forming apparatus characterized by:

Images