JP5935496B2 - Sheet conveying apparatus, image reading apparatus, and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet conveying apparatus, an image reading apparatus, and an image forming apparatus.

  In Patent Document 1, in a configuration in which the pickup roller and the feed roller are one roller unit, the pickup roller is maintained in a state of being separated from the sheet by using one spring, and a solenoid is used for feeding the sheet. There is described a paper feeding device which is turned on, presses a pickup roller against a paper sheet by its own weight and an action of another spring, and feeds the paper sheet.

Japanese Patent Laid-Open No. 5-4733

  An object of the present invention is to reduce the force required to maintain a state in which the first roller for feeding a sheet is in contact with the sheet in the sheet conveying apparatus.

The sheet conveying apparatus according to claim 1, wherein the first roller that feeds the sheet by rotating, the second roller that conveys the sheet fed by the first roller by rotating, and the first roller. And a support member that can rotate about the rotation axis of the second roller, a first member having a protrusion provided on the support member, and the support member the provided in the housing for rotatably supporting, a retaining means and a second member having a groove portion in which the protrusion is caught, the support member in a state in which the first roller is separated from said sheet holding means for holding a rotating driving means for generating a driving force rotation to, and transmits the driving force generated by the drive means to the second roller the second roller The first transmission mechanism and the second transmission for transmitting the driving force transmitted to the second roller to the first roller and rotating the first roller in the same direction as the second roller. A mechanism and a control means for controlling the driving means, and when the sheet is conveyed, the driving means is rotated to convey the sheet by the first roller and the second roller. And rotating the support member held by the holding means around the rotation axis of the second roller to cause the first roller to move in a direction approaching the sheet. in a state not held by the holding means, and a control means for contacting said first roller to said sheet, said when the protrusion and the groove is caught, press and the said groove the protrusion A pressing means for holding, the contact surfaces of the groove and the protrusion are not perpendicular to the direction of the circular motion of the first roller, and the second member is against the first member The first roller is located on the rotation center side in the circular motion .

  A sheet conveying apparatus according to a second aspect of the present invention is the sheet conveying apparatus according to the first aspect, wherein when the control means does not convey the sheet, the driving means is opposite to the case where the sheet is conveyed. And the support member is rotated about the rotation axis of the second roller to circularly move the first roller away from the sheet, and the support member is held by the holding means. It is characterized by making it.

  The sheet conveying apparatus according to claim 3 is the sheet conveying apparatus according to claim 1 or 2, wherein the holding force when the holding unit holds the first roller in a state of being separated from the sheet is A state in which the support member is larger than the force acting in the vertical direction due to the weight of the first roller and the first roller, and the support member is not held from the state held by the holding unit when the driving unit rotates in the other direction. It is characterized by being smaller than the force when trying to move to.

The sheet conveying apparatus according to claim 4 is the sheet conveying apparatus according to any one of claims 1 to 3 , wherein the holding unit has a portion extending in a direction having a vertical component from the groove portion. It is characterized by that.

An image reading apparatus according to a fifth aspect includes the sheet conveying apparatus according to any one of the first to fourth aspects and an image reading unit that reads an image from a sheet conveyed by the sheet conveying apparatus. Features.

An image forming apparatus according to a sixth aspect includes the image reading apparatus according to the fifth aspect and an image forming unit that forms an image read by the image reading apparatus on a recording medium.

According to the first aspect of the present invention, the first roller that feeds out the sheet is resisted against the force for separating the first roller from the sheet as compared with the case where the first roller is kept in contact with the sheet. The force required to maintain the first roller in contact with the sheet can be reduced. According to the first aspect of the present invention, the first roller is held as compared to the case where the groove portion is located outside the center of rotation in the circular motion of the first roller with respect to the protrusion. It becomes possible to easily shift from a state to a state where the state is not held.
According to the second aspect of the present invention, the first roller can be held in a state separated from the sheet when the sheet is not conveyed.
According to the third aspect of the present invention, it is possible to prevent the first roller from coming into contact with the sheet by the action of gravity from the state separated from the sheet .
According to the invention of 請 Motomeko 4 wherein, as compared to the structure without the site where the holding means is extended in a direction having a vertical component from the groove, the state in which the first roller when not conveying the sheet is not held It becomes easy to move to the held state.
According to the fifth aspect of the present invention, in order to maintain the state in which the first roller is in contact with the sheet as compared with the case where the sheet conveying device according to any one of the first to fourth aspects is not provided. It is possible to reduce the force required for the operation.
According to the invention described in claim 6 , compared with the case where the image reading device described in claim 5 is not provided, the force required for maintaining the state where the first roller is in contact with the sheet is obtained. Can be small.

1 is a schematic configuration diagram of an image forming apparatus provided with a sheet conveying device according to an embodiment of the present invention as seen from the front side. Block diagram showing the hardware configuration of the sheet conveying apparatus Magnified schematic diagram of the conveying part of the sheet conveying device when viewed from the front side The perspective view which looked at the upper conveyance guide and the lower conveyance guide from the front side Enlarged view of the transport section as seen from the front Perspective view of the drive mechanism from the front side Plan view of the feed roller and pickup roller as viewed in the vertical direction Side view showing lock member and hook-shaped member Sectional drawing showing the state in which the locking mechanism is locked Sectional drawing showing the state where the lock mechanism is released Schematic diagram for explaining the vertical movement of the pickup roller in the conventional example

<Embodiment>
<Configuration>
FIG. 1 is a schematic configuration diagram of an image forming apparatus 100 including a sheet conveying apparatus 10 according to an embodiment of the present invention as viewed from the front side. Here, the front side is a surface that is provided with operation means such as a touch panel and operation keys and faces when the user operates the image forming apparatus 100. On the other hand, the back side is a surface in the opposite direction to the front side. The image forming apparatus 100 is roughly divided into a sheet conveying device 10, a paper feeding unit 20, an image forming unit 30, and an image reading unit 40. The sheet conveying apparatus 10 is a sheet conveying apparatus that conveys a sheet to be read as a document to a reading position of the image reading unit 40 and discharges the sheet after the image reading. A sheet read as a document is an example of a sheet according to the present invention. The paper feeding unit 20 feeds the paper to the image forming position in the image forming unit 30. The image forming unit 30 forms an image on a sheet fed from the sheet feeding unit 20 through each process of electrophotography such as charging, exposure, development, transfer, and fixing. The image forming unit 30 is a unit that forms a color image in the present embodiment, but may be a unit that forms a monochrome image. The image reading unit 40 reads the image on the original that has been conveyed to the reading position in the sheet conveying apparatus 10 and supplies the read result to a control unit (not shown). The control unit supplies a reading result to the image forming unit 30 as necessary, and the image forming unit 30 forms an image corresponding to the supplied reading result on a sheet. The image reading unit 40 is an example of an image reading unit according to the present invention. An apparatus including at least the sheet conveying device 10 and the image reading unit 40 is an example of an image reading device according to the present invention.

  The sheet transport apparatus 10 includes a document stacking unit 11, a discharge paper stacking unit 12, and a transport unit 13. The document stacking unit 11 is a dish-like member on which a sheet to be read as a document is placed. The conveyance unit 13 is composed of a plurality of rollers, and conveys the document by rotation of these rollers. The sheet conveying apparatus 10 is attached to the image reading unit 40 through an opening / closing mechanism (not shown) such as a hinge so as to be freely opened and closed. The slit glass 14 is fitted into a part of the surface of the sheet conveying apparatus 10 that contacts the image reading unit 40. When the document is transported onto the slit glass 14 by the transport unit 13, the image reading unit 40 transmits the image on the document through the slit glass 14. The original on which the image has been read is discharged to the discharge paper stacking section 12 by the transport section 13.

  The paper supply unit 20 includes a paper storage unit 21 that stores paper, and a paper supply unit 22 that includes a plurality of rollers that convey the paper stored in the paper storage unit 21 to an image forming position in the image forming unit 30. Prepare.

  The image forming unit 30 forms an image using toner of four colors of yellow (Y), magenta (M), cyan (C), and black (K) by a so-called intermediate transfer method. The image forming unit 30 includes a photosensitive drum 31, a charger 32, an exposure device 33, a developing device 34, toner cartridges 35Y, 35M, 35C, and 35K, an intermediate transfer belt 36, and a fixing device 37. . In addition, among the components shown in FIG. 1, those with an alphabet (Y, M, C, or K) at the end of the reference sign indicate that the component corresponds to one of the above four colors. ing. Although these components are different in the color of the toner to be used, the main components and functions are common. Therefore, in the following description, when it is not necessary to distinguish each other in the description of these components, they will be collectively referred to as “toner cartridge 35” with the end of the reference numeral omitted.

  The photoconductive drum 31 is a cylindrical member that rotates around an axis with a photoconductive film laminated on the surface, and is an image holding body that holds an electrostatic latent image formed on the surface. The charger 32 charges the photosensitive drum 31 to a predetermined charging potential. The exposure device 33 exposes the photosensitive drum 31 to form an electrostatic latent image. The developing device 34 supplies toner to the electrostatic latent image, thereby developing the electrostatic latent image and forming an image on the surface of the photosensitive drum 31. The toner cartridge 35 stores toner of each color and supplies it to the developing device 34 as necessary. The intermediate transfer belt 36 is a unit that holds the toner image transferred from the photosensitive drum 31. The intermediate transfer belt 36 is supported by a plurality of support rolls, and its outer circumferential surface circulates in the direction indicated by the arrow A1 in the drawing. The fixing device 37 fixes the image on the paper by heating and pressurizing the paper on which the image is transferred from the intermediate transfer belt 36. The photosensitive drum 31, the charger 32, the exposure device 33, the developing device 34, the intermediate transfer belt 36, and the fixing device 37 are examples of the image forming unit according to the present invention. A portion of the image forming apparatus 100 excluding the sheet conveying apparatus 10 is referred to as a copying apparatus 50.

  FIG. 2 is a block diagram illustrating a hardware configuration of the sheet conveying apparatus 10 and the copying apparatus 50. The sheet conveying apparatus 10 includes a control unit 101, a storage unit 102, and a communication unit 103. Each part is electrically connected by a bus. The control unit 101 includes a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and a time measuring unit that measures time. The CPU controls each unit connected to the control unit 101 by executing a control program stored in the ROM or the storage unit 102. The control unit 101 is an example of a control unit according to the present invention. The storage unit 102 is a storage device such as a flash memory, and stores a control program, for example. The communication unit 103 communicates with the communication unit 183 of the main body of the image forming apparatus 100 under the control of the control unit 101.

  The copying apparatus 50 includes a control unit 181, a storage unit 182, a communication unit 183, a UI unit 184, and an image forming unit 30. Each part is connected by a bus. The control unit 181 includes a CPU, a ROM, and a RAM. The CPU controls each unit connected to the control unit 181 by executing a control program stored in the ROM or the storage unit 182. The storage unit 182 is a storage device such as a hard disk, and stores a control program and image data, for example. The communication unit 183 communicates with the communication unit 103 of the sheet conveying apparatus 10 and the communication terminal operated by the user under the control unit of the control unit 181. A UI (User Interface) unit 184 includes, for example, a touch panel and a plurality of keys, and notifies the control unit 181 of an instruction based on a user operation. The control unit 181 performs processing according to the instruction notified from the UI unit 184. As described above, the image forming unit 30 forms an image based on the image data on a sheet.

  FIG. 3 is an enlarged schematic diagram of the conveying unit 13 in the sheet conveying apparatus 10 as viewed from the front side. Hereinafter, only the main part according to the present embodiment will be described in FIG. 3, and the description of the other parts will be omitted. The conveyance unit 13 includes a pickup roller 111, a feed roller 112, a discharge roller 113, a driven roller 114, a normal conveyance path 130, a linked conveyance path 131, a reverse conveyance path 132, an upper conveyance guide 135, a lower conveyance guide A transport guide 136. Further, the transport unit 13 includes a plurality of rollers as shown in FIG. 3 and a drive mechanism (not shown in FIG. 3) for driving these rollers. The main part of the transport unit 13 and each roller will be described, and then the drive mechanism will be described.

  In the normal conveyance path 130, after the original is conveyed from the pickup roller 111 toward the feed roller 112, the original is conveyed to the position of the slit glass 14 by a plurality of rollers, and an image on the original is read at this position. This is a path when the sheet is conveyed to the position of the discharge roller 113. The position of the slit glass 14 is a reading position where an image on the document is read by the image reading unit 40. On the other hand, the linked conveyance path 131 connects a certain position (connection position L2) on the upstream side in the sheet conveyance direction with respect to the image reading position in the normal conveyance path 130 and a certain position (connection position L1) on the downstream side. It is a transport path. That is, in the normal conveyance path 130, the connection location L2 is located upstream of the connection location L1 in the paper conveyance direction. Hereinafter, the “paper transport direction” simply refers to the direction in which the document is transported toward the discharge roller 113 in the normal transport path 130. The reverse conveyance path 132 is a conveyance path positioned downstream of the connection location L1 in the paper conveyance direction, and the paper conveyance direction is reversed in the reverse conveyance path 132.

  The pickup roller 111 is located at the uppermost stream in the paper conveyance direction in the normal conveyance path 130, and the feed roller 112 is located downstream of the pickup roller 111 in the paper conveyance direction in the normal conveyance path 130, and a drive source is generated. It is rotated by the driven force. An endless belt is stretched between the pickup roller 111 and the feed roller 112, and the pickup roller 111 also rotates with the rotation of the feed roller 112, and the document placed on the document stacking unit 11 is placed inside the conveyance unit 13. Pull in. The feed roller 112 conveys the document drawn by the pickup roller 111. An electromagnetic clutch, which will be described later, is connected to the feed roller 112, and transmission of driving force from a driving source is controlled by this electromagnetic clutch. In the following, the state in which the driving side of the electromagnetic clutch is connected to the non-driving side by the on / off control of the electromagnet in the electromagnetic clutch is referred to as making the electromagnetic clutch connected, and the driving side of the electromagnetic clutch is not connected to the non-driving side Is called disengagement of the electromagnetic clutch. That is, when the electromagnetic clutch is in a disconnected state, the feed roller 112 does not rotate, and the pickup roller 111 does not rotate accordingly. The pickup roller 111 is an example of a first roller according to the present invention. The feed roller 112 is an example of a second roller according to the present invention.

  The discharge roller 113 is positioned on the reverse conveyance path 132 and is rotated by the driving force generated by the driving source to convey the document. The discharge roller 113 rotates in the forward rotation direction when discharging a document on which one-side reading or double-side reading of an image has been completed by the image reading unit 40 to the discharge sheet stacking unit 12. The discharge roller 113 rotates in the reverse direction to convey the original along the linkage conveyance path 131 when reversing the original on which the double-sided reading of the image is not completed. The rotation direction of the discharge roller 113 is switched by the control unit 101 controlling the rotation direction of the driving force. The driven roller 114 is provided at a position facing the discharge roller 113, and rotates following the rotation of the discharge roller 113.

  The upper conveyance guide 135 and the lower conveyance guide 136 are guide members that guide the document conveyance direction along the normal conveyance path 130. When the document is transported, its traveling direction is guided by the upper transport guide 135 and the lower transport guide 136. The upper transport guide 135 is located above the lower transport guide 136 in the vertical direction. The lower conveyance guide 136 guides conveyance of the document along the normal conveyance path 130 on the upstream side of the upper conveyance guide 135 in the sheet conveyance direction. The upper conveyance guide 135 and the lower conveyance guide 136 are coupled to each other by a coupling portion 137 at a position where the end portions far from the discharge roller 113 are in contact with each other.

  FIG. 4 is a perspective view of the upper transport guide 135 and the lower transport guide 136 as seen from the front side. The upper conveyance guide 135 and the lower conveyance guide 136 have a comb-teeth shape at both ends near the connecting portion 137. The upper conveyance guide 135 and the lower conveyance guide 136 are coupled by a rotation shaft extending in the depth direction in a state where the comb teeth are engaged with each other at the coupling portion 137. As a result, the upper transport guide 135 can rotate in a direction away from the lower transport guide 136 around the rotation axis of the connecting portion 137. For example, when a paper jam occurs in the sheet conveying apparatus 10, the user rotates the upper conveying guide 135 in a direction away from the lower conveying guide 136 to open the upper conveying guide 135 and expose the normal conveying path 130 to the outside. And remove the jammed document. In a state where the sheet conveying apparatus 10 is opened, the control unit 101 stops supplying power to the motor 140 and the electromagnetic clutch 143, the electromagnet in the electromagnetic clutch 143 is controlled to be turned off, and the electromagnetic clutch 143 is in a disconnected state. It becomes. Next, the drive mechanism will be described.

  FIG. 5 is an enlarged view when the drive mechanism of the transport unit 13 is viewed from the front side. In this figure, each member such as a roll and a gear constituting the drive mechanism is transparently shown. Hereinafter, only the main part according to the present embodiment will be described in FIG. 5, and description of other parts will be omitted. In FIG. 5, in order to express the position of each member in the depth direction, a step is provided in the depth, and the members at the depth position of each step are represented by lines having different shapes. First, the member located in the back when the conveyance part 13 is seen from the front side is represented by a solid line. Moreover, the member located in the one-step front side from the member represented with the continuous line is represented with a broken line. Moreover, the member located in the one-step front side from the member represented with the broken line is represented with a dashed-dotted line. Moreover, the member located in the one-step front side from the member represented with the dashed-dotted line is represented with a dashed-two dotted line. The members of the drive mechanism represented by the lines of these respective shapes are located on the back side from the respective rollers. Each roller is represented by a solid line that is thicker than the members of the drive mechanism. Note that description of parts that have already been described with reference to FIG. 3 is omitted.

  The transport unit 13 includes a motor 140, a large diameter gear 141, a small diameter gear 142, an electromagnetic clutch 143, and gears 144, 145, and 146 as drive mechanisms. It should be noted that the motor 140 shown in the figure actually represents a gear directly connected to the drive shaft of the motor. The large-diameter gear 141 and the small-diameter gear 142 have the same rotation shaft, and are, for example, two-stage gears. Moreover, the electromagnetic clutch 143 and the gear 144 have the same rotating shaft, for example, are two-stage gears. The electromagnetic clutch 143 has a gear that contacts and separates from the drive side by the action of an electromagnet, and this gear meshes with each gear. The gear 146 is connected to the rotation shaft of the feed roller 112. The gear 146 transmits the driving force generated by the motor 140 to the connected feed roller 112.

  The motor 140 selectively rotates in the normal rotation direction and the reverse rotation direction opposite to the normal rotation direction to generate a driving force. The motor 140 is an example of a driving unit according to the present invention. Here, transmission of the driving force between each roller and the gear will be described by taking as an example a case where the motor 140 rotates in the forward rotation direction. When the motor 140 rotates in the forward rotation direction, the gear directly connected to the drive shaft of the motor 140 rotates in the direction of the arrow R1 illustrated. As a result, the large-diameter gear 141 that meshes with the gear of the motor 140 rotates in the direction of arrow R2, and accordingly, the small-diameter gear 142 also rotates in the same direction R3. The small diameter gear 142 meshes with the gear of the electromagnetic clutch 143. Thereby, the drive side gear of the electromagnetic clutch 143 rotates in the arrow R4 direction. The electromagnetic clutch 143 controls transmission of driving force to the gear 144. That is, when the driving side gear of the electromagnetic clutch 143 is in a state separated from the driven side (that is, in a disconnected state), the driving force is not transmitted to the gear 144. On the other hand, when the driving side gear of the electromagnetic clutch 143 is in a state of being connected to the driven side (that is, in a connected state), the driving force is transmitted to the gear 144, and the gear 144 rotates in the direction of the arrow R5. The gear 144 meshes with the gear 145, and the gear 145 meshes with the gear 146. Thereby, the gear 145 rotates in the direction of the arrow R6, and the gear 146 rotates in the direction of the arrow R7 illustrated. The gear 146 transmits a driving force to the feed roller 112, and the feed roller 112 rotates in the direction of arrow R8 and in the direction of conveying the document. The large diameter gear 141, the small diameter gear 142, the electromagnetic clutch 143, and the gears 144, 145, and 146 are examples of the first transmission mechanism according to the present invention.

  FIG. 6 is a perspective view of the drive mechanism as seen from the front side. On the other hand, FIG. 7 is a plan view of the feed roller 112 and the pickup roller 111 as viewed in the vertical direction. In FIG. 6, some gear teeth are omitted for easy viewing. The rotation shaft 151 a connected to the gear 146 and the rotation shaft 151 b connected to the feed roller 112 are coaxial with each other at the position of the torque limiter 152 provided between the gear 146 and the feed roller 112. 151 is connected. The torque limiter 152 is a device that restricts or cuts off the transmission of the torque to the rotating shaft 151b when the torque of the rotating shaft 151a exceeds a predetermined set value. Thereby, the driving force transmitted from the motor 140 to the feed roller 112 is controlled. In addition, a box-shaped hollow belt storage frame 154 is provided so as to cover the rotation shaft 151b of the feed roller 112 and the rotation shaft 153 of the pickup roller 111 at a position between the torque limiter 152 and the feed roller 112. ing. Inside the belt storage frame 154, a belt 155 is stretched between the rotation shaft 151 b of the feed roller 112 and the rotation shaft 153 of the pickup roller 111. As a result, the driving force accompanying the rotation of the rotating shaft 151b is transmitted to the rotating shaft 153 via the belt 155, and the pickup roller 111 rotates in the same direction as the feed roller 112. The belt 155 is an example of a second transmission mechanism according to the present invention.

  When the motor 140 rotates in the forward direction, the pickup roller 111 moves circularly in the direction of the arrow Rk about the rotation shaft 151b (described later) along with the rotation of the support frame 156 about the rotation shaft 151b of the feed roller 112. ) Is moved down to the position where it comes down in the vertical direction and comes into contact with the document. Furthermore, the pickup roller 111 conveys the document in contact with the pickup roller 111 by the rotation of the feed roller 112 being transmitted. Further, when the motor 140 rotates in the reverse rotation direction, the pickup roller 111 performs a circular motion in the arrow Rj direction around the rotation shaft 151b as the support frame 156 rotates around the rotation shaft 151b of the feed roller 112. By doing so, it moves up in the vertical direction and moves to a position where it does not come into contact with the document. Hereinafter, when the pickup roller 111 is in a position where it comes down in the vertical direction and comes into contact with the document as a result of circular movement about the rotation shaft 151b, the pickup roller 111 is in a lowered state. Further, hereinafter, the pickup roller 111 is in a position where the pickup roller 111 is in a position where it rises with respect to the vertical direction and does not come into contact with the document as a result of circular movement about the rotation shaft 151b. .

  At the end far from the gear 146, the rotation shaft 151 b of the feed roller 112 and the rotation shaft 153 of the pickup roller 111 rotatably support the pickup roller 111 and rotate around the rotation shaft of the feed roller 112. A possible support frame 156 is provided. The support frame 156 is an example of a support member according to the present invention. As the feed roller 112 rotates, the support frame 156 also rotates about the rotation shaft 151b of the feed roller 112, whereby a force that makes a circular motion about the rotation shaft 151b acts on the pickup roller 111. A stopper 157 for catching a gate lock member, which will be described later, is provided at the end of the support frame 156 on the side close to the rotation shaft 153. Further, a hook-shaped member 160 is provided at a position between the feed roller 112 and the pickup roller 111 in the support frame 156. The hook-shaped member 160 has a hook-shaped protrusion 161 at the tip that extends upward in the vertical direction. The hook-shaped member 160 maintains the state where the pickup roller 111 is lifted with respect to the vertical direction by engaging with the lock member 170 attached to the upper conveyance guide 135.

  FIG. 8 is a side view showing the lock member 170 and the hook-shaped member 160. The lock member 170 extends in the vertical direction from the end attached to the upper conveyance guide 135. Further, a portion that is bent toward the flange-shaped member 160 in a portion where the lock member 170 extends is referred to as a groove portion 176. The protrusion 161 of the hook-shaped member 160 is caught in the groove 176 in the lock member 170.

  If the pickup roller 111 is in a lowered state at the timing when the user sets the document on the document stacking unit 11 before the document conveyance is started, the leading edge of the document hits the pickup roller 111 and the document is placed at an appropriate position. I can't set it. Therefore, in the present embodiment, the pickup roller 111 is maintained in the raised state by the lock member 170 and the hook-shaped member 160 being caught while the document is not being conveyed. As a result, the user can easily set the document on the document stacking unit 11 so that the upper surface of the document is placed below the pickup roller 111.

  The lock member 170 has a rotation shaft 151 and a shaft 171 extending in the direction along the rotation shaft 153 at the end opposite to the side that engages with the hook-shaped member 160. Both ends of the shaft 171 are rotatably attached to bearings provided on the upper conveyance guide 135. A coil spring 172 is wound around the shaft 171. One end of the coil spring 172 extends in a direction perpendicular to the shaft 171, and the spring tip 173 is bent in a hook shape toward the upper conveyance guide 135 and is in contact with the upper conveyance guide 135. When a force in the direction of arrow Ra1 is applied to the lock member 170, the shaft 171 rotates, and accordingly, a force in the direction of arrow Ra1 also acts on the coil spring 172 wound around the shaft 171. Then, the spring tip 173 of the coil spring 172 is pressed against the upper transport guide 135 by the force in the direction of the arrow Ra1, so that the spring tip 173 receives a reaction force from the upper transport guide 135. As a result, a force in the direction of arrow Ra2 acts on the shaft 171 around which the coil spring 172 is wound and the lock member 170 connected to the shaft 171. That is, the coil spring 172 generates a force that resists the lock member 170 in the opposite direction to the force acting in the direction downstream of the transport direction and closer to the upper transport guide 135. In this way, when the hook-shaped member 160 and the lock member 170 are caught, a force acting in the direction of the arrow Ra2 acts on the lock member 170 in the direction of the arrow Ra1, so that the hook-shaped member 160 is actuated. And the lock member 170 press each other.

  As described above, the hook-shaped member 160 is caught by the lock member 170, so that the support frame 156 is held in a state where the pickup roller 111 is separated from the document. The hook-shaped member 160, the protrusion 161, the lock member 170, the shaft 171, the coil spring 172, the spring tip 173, and the groove 176 are examples of the holding unit according to the present invention. The upper transport guide 135 is an example of a housing according to the present invention. The hook-shaped member 160 is an example of a first member according to the present invention, and the lock member 170 is an example of a second member according to the present invention. Further, the protrusion 161, the shaft 171, the coil spring 172, the spring tip 173, and the groove 176 are examples of pressing means according to the present invention. Hereinafter, both the hook-shaped member 160 and the lock member 170 are referred to as a lock mechanism. Hereinafter, the state where the hook-shaped member 160 and the lock member 170 are caught is referred to as a state where the lock mechanism is locked. Hereinafter, the state where the hook-shaped member 160 and the lock member 170 are not caught is referred to as a state where the lock mechanism is released.

  FIG. 9 is a cross-sectional view illustrating a state in which the lock mechanism is locked. The control unit 101 sets the rotation direction of the motor 140 in the reverse direction so that the pickup roller 111 is raised as an initial operation or an operation toward the next document transport after the document transport is finished. change. Here, the initial operation is, for example, an operation performed immediately after the power of the image forming apparatus 100 is turned on or immediately after an error such as a paper jam is resolved. When the rotation direction of the motor 140 is changed to the reverse rotation direction, the feed roller 112 rotates in the direction of the arrow Rb1, and accordingly, the support frame 156 rotates in the direction of the arrow Rb1, thereby the pickup supported by the support frame 156. The roller 111 performs a circular motion in the direction of the arrow Rc1. As a result, the hook-shaped member 160 moves in the direction of the arrow Rc1, and the protrusion 161 of the hook-shaped member 160 is caught by the groove 176 provided on the surface of the lock member 170 facing the hook-shaped member 160. The locking mechanism is locked. The dihedral angle formed by one slope and the other slope forming the groove 176 is designed to be larger than a right angle. The protrusion 161 has a triangular shape when viewed from the front side, and the lower surface 162 of the protrusion 161 is caught by the groove 176. As described above, the contact surface of the groove 176 and the protrusion 161 at the moment when the lock mechanism is locked or unlocked is not perpendicular to the direction of the circular motion of the pickup roller 111. When hooked in the groove 176, the resistance is small and easy to catch, and when the protrusion 161 is detached from the groove 176, the resistance is small and easy to come off.

  Further, the lock member 170 has a side surface portion 177 that is a portion extending from the groove portion 176 in a direction having a vertical component. The length of the side surface portion 177 is such a length that the lower surface 162 of the projection portion 161 comes into contact with the side surface portion 177 and slides and moves toward the groove portion 176 so that the projection portion 161 is easily caught by the groove portion 176. It is decided to. In addition, the lock member 170 which is a locked side is positioned on the rotation center side in the circular motion of the pickup roller 111 with respect to the hook-shaped member 160 which is a lock side in the lock mechanism. Thereby, when the lock mechanism is released, that is, when the pickup roller 111 moves circularly in the direction of the arrow Rc2, the direction of the force applied from the hook-shaped member 160 to the lock member 170 follows the rotation direction. Resistance to this force does not occur, and the lock is released smoothly.

  Further, in the lower conveyance guide 136, the document is positioned upstream of the feed roller 112 in the sheet conveyance direction and downstream of the pickup roller 111 in the sheet conveyance direction so that the document can be set at an appropriate position on the document stacking unit 11. A gate member 200 is provided as a reference for the set position of the tip. The gate member 200 has a spring (not shown), and when it receives a force in the paper transport direction, the gate member 200 falls in the paper transport direction and opens the paper transport path. Further, when the gate member 200 does not receive a force in the paper conveyance direction, the gate member 200 rises in the horizontal direction under the force of the spring. In this standing state, the gate member 200 is engaged with a gate lock member 190 (to be described later), so that the gate member 200 does not fall down even if a force applied when setting a document is applied.

  The gate member front end 201 of the gate member 200 is bent in a bowl shape toward the paper transport direction. The gate lock member 190 is a bar-like member, and has a first flange 191 at one end near the feed roller 112 and a second flange 192 at the other end far from the feed roller 112. The gate lock member 190 has a rotation shaft 151 and a shaft 193 extending in the direction along the rotation shaft 153 in the middle of the longitudinal direction thereof. The shaft 193 is fitted to a bearing 139 provided on the upper conveyance guide 135, and the gate lock member 190 is rotatable with respect to the upper conveyance guide 135.

  The holding force when holding the state where the protrusion 161 of the hook-shaped member 160 and the groove 176 of the lock member 170 are hooked is such that the pickup roller 111 and the like are pulled in the vertical direction by its own weight. The force is greater than the force for separating the protrusion 161 and the groove 176 of the lock member 170. On the other hand, this holding force is locked with the protrusion 161 of the bowl-shaped member 160 by the motor 140 rotating in the forward rotation direction (the direction of the arrow Rb2 shown in the figure) and the pickup roller 111 performing a circular motion in the direction of the arrow Rc2. The force is smaller than the force for separating the groove portion 176 of the member 170. In other words, this holding force is smaller than the force when the support frame 156 tries to move from the state held by the holding means to the state where it is not held. Therefore, for example, when the motor 140 rotates in the reverse direction during the initial operation or the like, the pickup roller 111 is in a raised state, and the pickup roller is locked when the lock mechanism by the hook-shaped member 160 and the lock member 170 is locked. The lock is not released due to its own weight. On the other hand, when the document is transported, the motor 140 rotates in the forward rotation direction, whereby the lock mechanism is unlocked by the torque applied to the rotating shaft 151b, and the pickup roller 111 is lowered.

  FIG. 10 is a side view showing a state in which the lock mechanism is released. For example, when the user presses a copy start or scan start button to start transporting a document, as described above, the motor 140 rotates in the forward rotation direction, whereby the torque applied to the rotation shaft 151b. As a result, the lock mechanism is unlocked and the pickup roller 111 is lowered. At this time, with the circular motion of the pickup roller 111, the stopper 157 of the support frame 156 is hooked on the second flange 192 of the gate lock member 190 and pushes it down, so that the gate lock member 190 is centered on the shaft 193. And rotate in the direction of arrow Rd1. As a result, the first flange portion 191 of the gate lock member 190 is detached from the gate member tip 201 of the gate member 200. In this state, when the gate member 200 receives a force in the conveyance direction from the document to be conveyed, since the catch between the first flange portion 191 and the gate member tip 201 is eliminated, the gate member 200 moves in the sheet conveyance direction. It will not fall over and prevent the document from being transported.

  Here, the effects of the present embodiment will be described in comparison with the conventional configuration for the present embodiment. FIGS. 11A and 11B are schematic diagrams for explaining the vertical movement of the pickup roller 111a in the conventional example. FIG. 11A shows a state where the pickup roller 111a is raised, and FIG. 11B shows a state where the pickup roller 111a is lowered. In the conventional example, in order to lift the pickup roller 111a, a support frame 156a provided so as to rotatably support the feed roller 112a and the pickup roller 111a from the surface of the upper conveyance guide 135a facing the sheet conveyance path. A spring 301 is attached toward the middle in the longitudinal direction. One end of the spring 301 is attached to the upper conveyance guide 135, and the other end of the spring 301 is attached to the support frame 156a. Due to the contraction force of the spring 301, the pickup roller 111a is pulled to the upper conveyance guide 135 side and lifted.

  In the conventional example, when the document is transported in such a configuration, the support frame 156a is rotated by the feed roller 112a as the feed roller 112a rotates in the Re1 direction as the motor 140 rotates in the forward rotation direction. , The pickup roller 111a performs a circular motion in the direction of the arrow Rf1 about the rotation shaft 151d. Thereby, the pickup roller 111a moves to a position where it is lowered in the vertical direction. At this time, the torque applied to the rotating shaft 151d is a state in which the feed roller 112a is rotated and the pickup roller 111a is moved in a circular motion and the paper 301 is pulled in the opposite direction against the contracting force of the spring 301 and is in contact with the paper. This is combined with the torque required to maintain the torque. That is, when the pickup roller 111a is lifted by using the contraction force of the spring 301 in this way, the torque necessary to bring the pickup roller 111a down is not only the rotation of the feed roller 112a but also the pickup. Not only the torque for causing the roller 111a to perform the circular motion, but also the torque for continuing to resist the contracting force of the spring 301 is required. That is, in such a case, the torque applied to the rotating shaft 151b also increases accordingly, and therefore a large torque limiter provided on the rotating shaft of the feed roller 112a is required. As a result, the cost is increased and the space is saved. But it becomes a problem. Further, in such a case, the motor 140 is also increased in size in proportion to the required torque, so that this is also costly and causes a problem in terms of space saving.

  On the other hand, in this embodiment, by providing the lock mechanism, once the pickup roller 111 is lifted to lock the lock mechanism, an additional torque is then applied to maintain the pickup roller 111 in the raised state. do not need. That is, in this embodiment, it is not necessary to continue pulling the pickup roller 111 by the spring 301 as in the above-described conventional example. For this reason, in the present embodiment, the torque required for setting the pickup roller 111 in the lowered state is sufficient only for rotating the feed roller 112 and causing the pickup roller 111 to perform a circular motion. As a result, the torque applied to the rotating shaft 151b does not include the torque that continues to resist the spring 301 as in the above-described conventional example, and the torque required by the motor 140 when the pickup roller 111 is raised to that extent. It will be small. In accordance with this, the torque limiter 152 and the motor 140 provided on the rotating shaft 151 can be reduced in size.

  In this embodiment, the torque generated by driving the motor 140 is not divided into the torque for resisting the spring 301 as in the conventional example, and the feed roller 112 is rotated and the pickup roller 111 is moved circularly. Can only be used. As a result, the force generated by the torque is sufficiently transmitted when the pickup roller 111 comes into contact with the sheet, and the document is conveyed in a state where the contact pressure applied to the document is increased.

  Further, the spring 301 is not used as in the above-described conventional example, but in the case of a configuration that does not have a locking mechanism as in the present embodiment, the following is obtained. That is, in such a case, when the document is not transported, the motor 140 rotates in the reverse direction, and the pickup roller 111 performs a circular motion in a direction approaching the upper transport guide 135 around the rotation shaft 151. At this time, there is no mechanism for maintaining the lifted state. Therefore, when the upper conveying guide 135 is rotated with respect to the lower conveying guide 136 and the sheet conveying apparatus 10 is opened, the electromagnetic clutch 143 is disconnected and the pickup roller 111 moves in a circular motion. When the force to be interrupted is interrupted, the pickup roller 111 is lowered in the vertical direction by its own weight. As a result, the control unit 101 needs to rotate the motor 140 in the reverse direction to bring the pickup roller 111 up again in preparation for the start of document conveyance. In contrast, in the present embodiment, even when the upper conveyance guide 135 is rotated with respect to the lower conveyance guide 136 and the sheet conveyance apparatus 10 is opened, the pickup roller 111 is lowered due to its own weight. Therefore, it is not necessary for the control unit 101 to rotate the motor 140 in the reverse direction in order to keep the pickup roller 111 in the raised state. As a result, compared to the case where the lock mechanism is not provided, in this embodiment, a time loss when starting the conveyance of the document is prevented.

  Thus, according to the present embodiment, in the sheet conveying apparatus 10, it is possible to reduce the torque required by the motor 140 when the pickup roller 111 located at the most upstream in the conveying direction is lifted in the vertical direction.

(Modification)
The second transmission mechanism in the present invention is not limited to a belt but may be a gear. However, in this case, it is necessary that the rotation is transmitted to the pickup roller 111 when the feed roller 112 is rotated, and the pickup roller 111 moves circularly when the support frame 156 rotates.

DESCRIPTION OF SYMBOLS 10 ... Sheet conveying apparatus, 11 ... Document stacking part, 12 ... Discharged paper stacking part, 13 ... Conveying part, 14 ... Slit glass, 20 ... Paper feeding part, 21 ... Paper storage part, 22 ... Paper feeding means, 30 ... Image Forming unit 31 ... photosensitive drum, 32 ... charger, 33 ... exposure device, 34 ... developing device, 35 ... toner cartridge, 36 ... intermediate transfer belt, 37 ... fixing device, 40 ... image reading unit, 101 ... control unit DESCRIPTION OF SYMBOLS 102 ... Memory | storage part 103 ... Communication part 111 ... Pick-up roller 112 ... Feed roller 113 ... Discharge roller 114 ... Follower roller 130 ... Normal conveyance path 131 ... Link conveyance path 132 ... Reverse conveyance path 135 ... Upper conveyance guide, 136 ... Lower conveyance guide, 137 ... Connection part, 139 ... Bearing, 140 ... Motor, 141 ... Large diameter gear, 142 ... Small diameter gear, 143 ... Electromagnetic clutch, 44, 145, 146 ... gears, 151, 151a, 151b, 153 ... rotating shaft, 152 ... torque limiter, 154 ... belt storage frame, 155 ... belt, 156 ... support frame, 157 ... stopper, 160 ... hook-like member, 161 ... Projection part 162 ... Lower surface 170 ... Lock member 171,193 ... Shaft 172 ... Coil spring 173 ... Tip 176 ... Groove part 177 ... Side face 181 ... Control part 182 ... Storage part 183 ... Communication part 184 ... UI part, 190 ... Gate lock member, 191 ... Second collar part, 192 ... Third collar part, 200 ... Gate member, 201 ... Gate member tip

Claims (6)

A first roller that feeds the sheet by rotating;
A second roller that conveys the sheet fed by the first roller by rotating;
A support member rotatably supporting the first roller and rotatable about a rotation axis of the second roller;
A holding member having a first member having a protrusion provided on the support member and a second member having a groove part on which the protrusion is caught provided on a housing that rotatably supports the support member. and means, holding means for holding the support member in a state in which the first roller is separated from the sheet,
A driving means for rotating to generate a driving force;
A first transmission mechanism for transmitting the driving force generated by the driving means to the second roller to rotate the second roller;
A second transmission mechanism that transmits the driving force transmitted to the second roller to the first roller and rotates the first roller in the same direction as the second roller;
Control means for controlling the driving means. When the sheet is conveyed, the driving means is rotated to rotate the first roller and the second roller in the direction of conveying the sheet. And rotating the support member held by the holding means about the rotation axis of the second roller to cause the first roller to move circularly in a direction approaching the sheet. Control means for bringing the first roller into contact with the sheet ,
A pressing means that presses the projection and the groove when the projection and the groove are hooked;
The contact surfaces of the groove and the protrusion are not perpendicular to the direction of the circular movement of the first roller, and the second member is the circle of the first roller with respect to the first member. Located on the center of rotation in motion
Sheet conveying apparatus characterized by and this. When the sheet is not conveyed, the control unit rotates the driving unit in a direction opposite to that when the sheet is conveyed, so that the support member is centered on the rotation axis of the second roller. The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus rotates the first roller to move in a direction away from the sheet and holds the supporting member by the holding unit. The holding force when the holding means holds the first roller away from the sheet is larger than the force acting in the vertical direction by the weight of the support member and the first roller, and the driving means 3. The force according to claim 1, wherein the force is smaller than a force when the support member tries to move from a state held by the holding means to a state where it is not held when the support member rotates in the other direction. Sheet conveying device. Before SL retaining means, the sheet conveying device according to any one of claims 1 to 3, characterized in that it has a portion extending in a direction having a vertical component from the groove. A sheet conveying device according to any one of 請 Motomeko 1-4,
An image reading device comprising: an image reading unit that reads an image from a sheet conveyed by the sheet conveying device. An image reading apparatus according to 請 Motomeko 5,
An image forming apparatus comprising: an image forming unit that forms an image read by the image reading apparatus on a recording medium.

Images