JP2007306155A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a very simple structure while ensuring an easy closing operation of a lid member for an apparatus main body and a gradual closing operation of the lid member. <P>SOLUTION: A shock absorbing mechanism 40 provided between the apparatus main body 20 and an original reading device 30 has a sect gear 41 protruding from the original reading device 30, and entering into the apparatus main body 20; a damper device 43 provided on the apparatus main body 20, and provided with a relay gear 42 geared with the sect gear 41, and rotatable around a damper shaft 432; and a holding member 44 for holding the damper device 43. The holding member 44 is provided with an inclined surface 447 used for guiding the damper device 43 to an upper position L2 at which the engagement of the relay gear 42 with the sect gear 41 is released in response to a releasing operation of the original reading device 30, and for guiding the damper device 43 to a lower position L1 at which the relay gear 42 is geared with the sect gear 41 in response to a closing operation of the original reading device 30. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus having a lid member such as a document reading apparatus attached to an upper surface of an apparatus main body so as to be opened and closed.

  2. Description of the Related Art Conventionally, an image forming apparatus (an inkjet printer in Patent Document 1) provided with a stacker (corresponding to the lid member of the present invention) that receives discharge paper that can be opened and closed with respect to a main body as described in Patent Document 1 is known. It has been. Between the stacker and the main body, there are a gear which rotates forward and backward integrally around the gear shaft according to the opening / closing operation of the stacker, and a braking portion (corresponding to the damper device of the present invention) for braking the rotation of the gear shaft as a buffer mechanism. It is installed.

  The braking part is provided with a one-way clutch that relays the rotation of the gear shaft to the braking mechanism. The one-way clutch has a pair of clutch plates configured to be detachable from each other. When the stacker is closed, the clutch plate is connected so that the closing operation of the stacker includes the gear shaft and the one-way clutch. On the other hand, when the stacker is released, the clutch plate is separated so that the opening operation is not transmitted to the braking mechanism of the braking unit.

In the image forming apparatus having such a configuration, the braking unit functions when the stacker is closed and the stacking operation is gently performed. On the other hand, when the stacker is opened, the opening operation is cut off from the braking unit. Therefore, the stacker can be opened quickly.
JP 2005-154115 A

  Incidentally, in the image forming apparatus described in Patent Document 1, a one-way clutch is provided between the stacker and the braking mechanism of the braking unit as a buffer mechanism, and a control mechanism for operating the one-way clutch is provided. In addition, since the buffer mechanism has a complicated structure with a large number of parts, there is a problem that the parts cost and the assembling cost increase.

  The present invention has been made to solve the conventional problems, and it is easy to open the lid member with respect to the main body of the apparatus and to ensure that the lid member is gently closed. An object of the present invention is to provide an image forming apparatus capable of contributing to reduction of component cost and assembly cost by adopting an extremely simple structure.

  According to a first aspect of the present invention, there is provided an apparatus main body in which various members for image formation are installed, and an upper surface of the apparatus main body by rotating forward and backward around a horizontal axis provided at one edge of the upper portion of the apparatus main body. In contrast, in the image forming apparatus including a lid member that changes the posture between a closed posture and an open posture, a buffer mechanism that cushions an opening / closing operation of the lid member is interposed between the device main body and the lid member. The shock absorbing mechanism protrudes from the lid member and enters the apparatus main body, and has a sect gear whose center of curvature is the axis of the horizontal axis, and is provided in the apparatus main body, and the sect gear A damper device having a relay gear rotatable about a gear shaft, and a holding member for holding the damper device, wherein the holding member moves the damper device according to an opening operation of the lid member. The center of the relay gear A guide member that guides the damper device to a meshing position where the relay gear meshes with the sect gear according to a closing operation of the lid member while guiding to the retracted position where the meshing with the gear is eliminated. It is what.

  According to this configuration, when closing the lid member in the open state, the closing operation is performed on the damper device located at the meshing position via the sect gear provided on the lid member and the relay gear meshed with the sect gear. Since the transmission is transmitted and the closing operation of the lid member is buffered by the buffering action of the damper device, the lid member is gently closed.

  On the other hand, when the lid member in the closed state is opened, the position of the damper device is changed by the action of the guide member from the meshing position to the retracted position where the meshing of the relay gear with the sect gear is canceled by the opening operation. The opening operation of the lid member is cut off from the damper device, whereby the lid member is easily and quickly opened without receiving the buffering action of the damper device.

  In this way, the holding member that holds the damper device guides the damper device to the retreat position where the meshing of the relay gear with the sect gear is canceled according to the opening operation of the lid member, while the damper device is guided according to the closing operation of the lid member. By providing a guide member that guides the relay gear to the meshing position where it meshes with the sect gear, there is no need to provide an expensive one-way clutch with a complicated structure as in the prior art, and the number of parts and parts cost can be reduced accordingly. .

  According to a second aspect of the present invention, in the first aspect of the present invention, the damper device includes a guided member guided by the guide member, and the holding member is provided on the tooth surface of the sect gear. A holding groove for holding the guided member in a state where the tooth surfaces are opposed to each other, and the guide member is opposed to the tooth surface of the sect gear in the holding groove and is separated by a groove wall that is separated from the sect gear. The groove wall is formed and is inclined upward from the groove bottom.

  According to such a configuration, when the lid member is closed, the guided member of the damper device is positioned at the groove bottom of the holding groove of the holding member, and the relay gear meshes with the sect gear. When the lid member is opened in this state, the sect gear rotates upward around the horizontal axis at the meshing position with the relay gear, so that the relay gear tries to rotate in the opposite direction to the sect gear. The groove wall as a guide member formed by the groove wall facing the tooth surface of the sect gear and spaced away from the sect gear is inclined upward from the groove bottom, so that it receives the transmission of force from the sect gear. The relay gear is moved obliquely with the inclined surface of the groove wall facing upward, whereby the meshing state with the sect gear is eliminated.

  When the tooth of the relay gear comes off from the tooth of the sect gear by this movement, the relay gear tries to descend due to its own weight, but the relay gear is pushed up again by the next tooth of the sect gear, so the relay gear is The teeth facing the sect gear are always pushed up as they collide with the teeth of the sect gear that rises sequentially according to the rotation of the sect gear about the horizontal axis, and eventually a damper having a relay gear and a guided member The device does not return to the bottom of the holding groove during the opening operation of the lid member, and the opening operation of the lid member is in a state of cutting off from the damper member.

  On the other hand, when closing the lid member once opened, the sect gear rotates around the horizontal axis in the direction opposite to that when opened and the teeth of the sect gear meshing with the relay gear are lowered. Therefore, not only the upward force does not act on the teeth of the relay gear meshing with the sect gear, but the downward force acts conversely, which causes the guided member to be inclined by its own weight and the weight of the damper device. It descends along the groove wall and reaches the groove bottom. When the guided member reaches the groove bottom of the holding groove, the meshing state of the relay gear and the sect gear is ensured. Thereafter, the rotation of the sect gear around the horizontal axis is transmitted to the damper device via the relay gear. Thus, the closing operation of the lid member becomes gentle.

  Thus, the damper device is provided with a guided member guided by the guide member, and the holding member is provided with a holding groove for holding the guided member in a state where the tooth surface of the relay gear faces the tooth surface of the sect gear. The guide member is formed by the groove wall facing the tooth surface of the sect gear in the holding groove and separated from the sect gear, so that the buffer acts only when the lid member is closed and does not act when the lid member is opened. The structure is extremely simple.

  According to a third aspect of the present invention, in the second aspect of the present invention, the holding groove is provided with a retaining piece for retaining the guided member.

  According to such a configuration, even if the guided member repeatedly moves up and down in the holding groove by the opening and closing operation of the lid member, the guided member is prevented from being detached from the holding groove by being blocked by the retaining piece provided in the holding groove. Such an inconvenience is reliably prevented.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the lid member is a document reading device that reads an image of a document and transmits it to an exposure device built in the apparatus main body. It is characterized by this.

  According to such a configuration, the document reading device as a lid member for closing the upper surface of the apparatus main body has the contact glass on which the document is placed at the top, and a mechanism for scanning the document image inside. An optical system, and further, a heavy object equipped with a CCD (charge coupled device) image sensor or the like, and the heavy object is applied as the lid member of claim 1 so that the image reading apparatus can be easily opened. At the same time, the closing is performed slowly, and the adverse effect on the internal structure due to the abrupt closing is avoided.

  According to the first aspect of the present invention, the holding member that holds the damper device guides the damper device to the retracted position where the meshing of the relay gear with the sect gear is released according to the opening operation of the lid member, while the lid member is closed. By providing a guide member that guides the damper device to the meshing position where the relay gear meshes with the sect gear according to the operation, this guide member has an extremely different structure compared to the one-way clutch having a complicated structure conventionally employed. Since it can be made simple, it is possible to achieve a reduction in the number of parts and the part cost, because it is not necessary to provide an expensive one-way clutch.

  According to the second aspect of the present invention, the guided member is guided by the guide member in the damper device, and the guided member is disposed in the state where the tooth surface of the relay gear is opposed to the tooth surface of the sect gear. A holding groove for holding is provided, and the guide member is formed by a groove wall facing the tooth surface of the sect gear in the holding groove and separated from the sect gear, so that it acts only when the lid member is closed. It is possible to make the buffer structure which does not work when the door is opened very simple.

  According to the third aspect of the invention, since the retaining groove is provided with the retaining piece for retaining the guided member, even if the guided member repeatedly moves up and down in the retaining groove by the opening / closing operation of the lid member. Thus, it is possible to reliably prevent the occurrence of inconvenience that the guided member comes off the holding groove.

  According to the second aspect of the present invention, by applying the heavy-weight image reading device as the lid member of the first aspect, the opening operation is facilitated, the closing is performed slowly, and the internal due to the sudden closing is performed. Adverse effects on the structure can be avoided.

  FIG. 1 is a diagram showing an embodiment of an image forming apparatus 10 according to the present invention. FIG. 1 (A) is a perspective view of an appearance, and FIGS. 1 (B) and 1 (C) are side sectional views. FIG. 1B is a diagram illustrating a state in which the document reading device 30 is set to the closing posture S1, and FIG. 1C is a state in which the document reading device 30 is set to the opening posture S2. Each is shown. In FIG. 1, the XX direction is referred to as the left-right direction, and the YY direction is referred to as the front-rear direction. In particular, the -X direction is referred to as the left, the + X direction is referred to as the right, the -Y direction is referred to as the front, and the + Y direction is referred to as the rear.

  First, as shown in FIG. 1A, the image forming apparatus 10 according to the present embodiment is a so-called in-body discharge type, and various image forming members are mounted therein. The apparatus main body 20 and a document reading device (lid member) 30 provided on the upper portion of the device main body 20 via the connecting portion 11 are basically configured, and between the device main body 20 and the document reading device 30, the apparatus main body. A paper discharge tray 12 for discharging the fixed paper P is formed on the top of the paper 20. The connecting portion 11 is erected on the rear portion of the apparatus main body 20.

  As shown in FIGS. 1 (A) and 1 (B), the apparatus main body 20 includes a photosensitive drum 22, a charging device 23, an exposure device 24, and a developing unit in a box-shaped lower exterior cover body 21. A device 25, a cleaning device 26, a fixing device 27, and the like are mounted. A removable paper cassette 28 is attached to the bottom of the lower exterior cover body 21. In the image forming process, sheets P are fed one by one from the sheet cassette 28 to the photosensitive drum 22, and an image based on image information read by the document reading device 30 is transferred to the sheet P. ing.

  The photosensitive drum 22 is provided so as to be rotatable about an axis, and an electrostatic latent image and a toner image are formed on the peripheral surface thereof while rotating. The toner image on the peripheral surface is transferred to the paper P. Thus, a transfer process is performed on the paper P.

  The charging device 23 applies a uniform charge to the peripheral surface of the photosensitive drum 22 rotating around the axis, and the exposure device 24 is a photosensitive member on which the uniform charge is formed. An electrostatic latent image is formed by irradiating the circumferential surface of the drum 22 with a light beam based on image information of the document image read by the document reading device 30. The toner is supplied to the electrostatic latent image formed on the toner to form a toner image, and the cleaning device 26 remains on the circumferential surface of the photosensitive drum 22 after the toner image is transferred to the paper P. Residual toner is removed for cleaning.

  The fixing device 27 performs a fixing process on the toner image of the paper P transferred from the peripheral surface of the photosensitive drum 22, and includes a fixing roller 271 having a heating element therein and a peripheral surface thereof. The sheet P after the transfer process is made up of heat from the fixing roller 271 while passing between the fixing roller 271 and the pressure roller 272. And the fixing process is performed.

  Then, the sheet P after the fixing process is raised through the inside of the connecting portion 11 and is discharged toward a paper discharge tray 12 provided at a front position of the connecting portion 11.

  The document reading device 30 includes various members for reading a document image in the upper exterior cover body 31 having a flat rectangular parallelepiped shape, such as a light source lamp, a reflecting mirror, a moving mechanism for moving the light source lamp and the reflecting mirror, and A CCD (charge coupled device) image sensor or the like that receives the reflected light of the document surface through a reflecting mirror is built in, and a document pressing cover 32 that can be opened and closed is provided on the upper surface.

  A contact glass 33 (FIG. 1B) for placing a document is fitted into the upper surface opening of the upper exterior cover body 31. The document pressing cover 32 can be opened and closed by rotating forward and backward with a predetermined portion of the rear edge as a fulcrum, and can close the document placed on the contact glass 33 by being closed. ing.

  An operation console 311 is provided at the front of the upper exterior cover body 31 so as to project outward, and predetermined push button operations are performed on various operation keys provided on the operation console 311. By doing so, an image forming process according to the set condition is executed.

  In the present embodiment, the developing device 25 loaded with toner is detachably attached to the apparatus main body 20. When the toner is consumed, the developing device 25 is updated with a new one (FIG. 1C).

  In order to replace the developing device 25 with a new one, the front side of the paper discharge tray 12 rotates counterclockwise around a predetermined horizontal axis as shown in FIG. The front upper part of can be opened. When the paper discharge tray 12 is opened, the paper discharge tray 12 interferes with the upper document reading device 30. Therefore, when the paper discharge tray 12 is opened, the closing posture S1 (FIG. 1B) is preceded. ) Is changed to the open posture S2 (FIG. 1C).

  The document reading device 30 is pivotally supported around a support shaft (horizontal shaft) 34 provided in the left and right direction at the rear end thereof provided on the upper portion of the connecting portion 11, and is in a closed posture shown in FIG. By turning clockwise around the support shaft 34 with the posture set to S1, the posture is changed to the open posture S2 as shown in FIG. 1 (C) and FIG. Yes. Accordingly, when replacing the developing device 25 with a new one, as shown in FIG. 1C, first, the paper discharge tray 12 is opened with the document reading device 30 opened and set in the open posture S2. .

  A projecting arm 29 that is pivotally supported around an unillustrated shaft is provided at a position in front of the upper surface of the apparatus main body 20, and the projecting arm 29 is in a state where the document reading device 30 is opened. By supporting the document reading device 30, the open posture S2 of the document reading device 30 is maintained.

  In the image forming apparatus 10 configured as described above, a buffer mechanism 40 that buffers the opening / closing operation of the document reading device 30 is interposed between the apparatus main body 20 and the document reading device 30. Hereinafter, the buffer mechanism 40 will be described with reference to FIGS. FIG. 2 is a partial perspective view of the image forming apparatus 10 for explaining the buffer mechanism 40. 3 is a perspective view showing an embodiment of the buffer mechanism 40. FIG. 3A is a state in which the damper device 43 is removed from the holding member 44, and FIG. Are respectively shown in a state of being mounted on the holding member 44. FIG. 4 is an enlarged perspective view showing an embodiment of the holding member 44, and also shows the positional relationship between the holding member 44 and the damper device 43. 2 to 4 are the same as those in FIG. 1 (X is the left-right direction (-X: leftward, + X: rightward), Y is the front-rear direction (-Y: forward, + Y: backward)).

  First, as shown in FIG. 2, the buffer mechanism 40 protrudes downward from the document reading device 30 and enters the apparatus main body 20. The buffer mechanism 40 is provided on the apparatus main body 20 side to the sect gear 41. A meshing relay gear 42, a damper device 43 concentrically connected to the relay gear 42, and a holding member 44 that holds the damper device 43 are configured.

  The sect gear 41 has an arcuate circumferential surface set so that the center of curvature is the axis of the support shaft 34. The upper end of the sect gear 41 is fixed to the right corner of the front end of the upper exterior cover body 31 of the document reading device 30 and hangs downward.

  On the other hand, the damper device 43 and the holding member 44 are mounted on a rectangular horizontal upper edge frame plate 201 in plan view provided on the upper right edge of the device body 20 so as to correspond to the sect gear 41. .

  As shown in FIG. 2, the upper edge frame plate 201 protrudes forward from the right front edge of the support frame 209 that supports the document reading device 30 provided on the rear upper surface of the apparatus main body 20. . As shown in FIG. 3A, the upper edge frame plate 201 is provided with a bowl-shaped edge weir 202 having an L-shape in plan view for mounting the support base 433 at the rear left corner. It has been.

  Further, on the upper edge frame plate 201 and the portion extending in the left-right direction of the bowl-shaped edge weir 202, the positioning protrusions 203 facing each other before and after positioning the support base 433 mounted on the upper edge frame plate 201 are provided. Are projected.

  A holding member mounting recess 204 for mounting the holding member 44 extending in the front-rear direction is provided in the right position of the pair of positioning projections 203 on the upper edge frame plate 201. Is fitted in the holding member mounting recess 204 in a positioned state.

  As shown in FIG. 3A, the damper device 43 includes a short cylindrical casing (guided member) 431 that extends in the left-right direction, and a damper shaft that extends in the left-right direction concentrically with the casing 431. (Gear shaft) 432, a plurality of baffle plates (not shown) projecting radially from the peripheral surface of the damper shaft 432, and a support base 433 that is rectangular in plan view for integrally supporting the casing 431. And.

  The damper shaft 432 is concentric with the casing 431 and protrudes from the casing 431 toward the right. The relay gear 42 is concentrically fitted on the right end portion of the damper shaft 432 protruding rightward from the casing 431 so as to be integrally rotatable.

  The casing 431 is filled with buffer oil, and the damper device 43 exhibits a buffer action due to the resistance of the buffer oil when the internally installed baffle plate rotates integrally around the damper shaft 432.

  Therefore, when the sect gear 41 is rotated forward and backward around the support shaft 34 by opening and closing the document reading device 30, the rotation of the sect gear 41 is obstructed in the damper device 43 via the relay gear 42 and the damper shaft 432. When the baffle plate is transmitted to the plate and rotates around the damper shaft 432 to stir the buffer oil, the closing operation of the document reading device 30 is gently performed by the resistance at this time.

  The left edge of the support base 433 is fixed to the lower part of the left side of the casing 431, so that the casing 431 protrudes rightward from the support base 433 as a guided member according to the present invention. In the support base 433, positioning grooves 434 corresponding to the pair of positioning protrusions 203 are respectively provided in the front and rear edges, and the pair of positioning grooves 434 are fitted into the corresponding positioning protrusions 203, respectively. The device 43 is allowed to move in the vertical direction while being guided by the positioning protrusion 203 in a state in which the movement in the front-rear and left-right directions is restricted.

  Each positioning projection 203 is set in a state where the damper device 43 is set at a lower position (meshing position) L1 (see FIG. 5A) described later, and each corresponding positioning groove 434 is provided in each positioning projection 203. On the other hand, the upper and lower dimensions are set so that the positioning groove 434 is disengaged from the positioning projection 203 in a state where the damper device 43 is set at an upper position (retracted position) L2 (see FIG. 5B) described later. Yes.

  When the damper device 43 supported by the holding member 44 is set to the upper position L2, the positioning groove 434 is disengaged from the positioning projection 203, thereby preventing the damper device 43 from moving forward and backward from the holding member 44. Accordingly, a left screen projection 205 is provided at the left side of the holding member 44 on the upper edge frame plate 201 so as to project upward, and a right screen projection is provided at a portion extending in the front-rear direction of the bowl-shaped edge weir 202. 206 protrudes upward.

  As shown in FIG. 4, the holding member 44 supports a damper base 43, which is long in the front-rear direction and protrudes upward from a substantially central portion of the base square 441. A bifurcated member 422 for guiding the level change of the damper device 43 between the position L1 and the upper position L2 is provided.

  The base square member 441 is dimensioned so that it can be fitted in the holding member mounting recess 204 (FIG. 3) of the upper edge frame plate 201 in a positioned state. Therefore, once the basic square member 441 is mounted once fitted into the holding member mounting recess 204, the mounted state becomes extremely stable.

  The bifurcated member 422 includes a front support column 443 projecting slightly upward from the front position from the center portion in the front-rear direction, and a rear support column 444 projecting upward from the same rear position. . A holding groove 445 for holding the casing 431 of the damper device 43 is formed between the front and rear support columns 443 and 444. The groove bottom of the holding groove 445 is an arc groove 446 formed in an arc shape whose radius of curvature is slightly larger than the radius of the outer periphery of the casing 431, so that the damper device 43 is positioned at the lower position L 1. The circumferential surface of the casing 431 is in close contact with the arc surface of the arc groove 446.

  The front edge surface of the rear column 444 is formed perpendicular to the direction in which the base square member 441 extends, while the rear edge surface of the front column 443 is inclined forwardly from the arc groove 446 toward the front. An inclined surface (groove wall) 447 is provided. The inclined surface 447 is set to have an inclination angle of about 60 ° with respect to the extending direction of the base square member 441, whereby the casing 431 is raised along the inclined surface 447 to a slightly lower level from the upper limit position. The meshing with the sect gear 41 is eliminated.

  Further, retaining pieces 448 projecting in the facing direction are provided on the facing surfaces of the upper ends of the front and rear columns 443 and 444, respectively. The distance between the pair of retaining pieces 448 is slightly shorter than the outer diameter dimension of the casing 431, whereby the casing 431 is prevented from being pulled upward from the inside of the holding groove 445.

  Hereinafter, the operation of the buffer mechanism 40 thus configured will be described with reference to FIG. FIG. 5 is a side sectional view for explaining the operation of the buffer mechanism 40. FIG. 5A shows a state in which the damper device 43 is set at the lower position L1, and FIG. The state where the damper device 43 is set to the upper position L2 is shown. In addition, the direction display by the arrow in FIG. 5 is the same as in the case of FIG. 1 (−Y: forward, + Y: backward).

  First, when the document reading device 30 is rotated in the counterclockwise direction around the support shaft 34 (FIG. 2) to operate the document reading device 30 in the closing direction, the sect gear 41 is moved to the position shown in FIG. As shown by the arrows in FIG. 6, the teeth of the sect gear 41 move downward and press the teeth of the relay gear 42 downward, so that the relay gear 42 is moved around the damper shaft 432. A force for rotating the damper device 43 in the lower position L1 via the relay gear 42 is applied to the damper device 43 in a downward direction.

  However, since the casing 431 is fitted in the arc groove 446 at the bottom of the holding groove 445, the damper device 43 does not move downward due to being blocked by the arc groove 446. Therefore, the relay gear 42 does not move to the damper shaft. The document reading device 30 is rotated around 432 in the clockwise direction, and the operation of the damper device 43 causes the closing operation to be buffered via the sect gear 41 and is gradually closed.

  On the other hand, as shown in FIG. 5A, when the document reading device 30 is opened while the damper device 43 is set at the lower position L1, the sect gear 41 rises and the teeth of the relay gear 42 are moved. Since the teeth of the sect gear 41 meshing with the teeth press the teeth of the relay gear 42 upward, a force that causes the relay gear 42 to rotate the relay gear 42 around the damper shaft 432 counterclockwise. Is applied to the damper device 43 via the relay gear 42, and a force for directing the damper device 43 upward is applied to the damper device 43.

  By the way, since the damper device 43 is set so that its weight is smaller (lighter) than the buffering force of the damper device 43, the relay gear 42 meshing with the sect gear 41 does not rotate even when the sect gear 41 is raised. The damper device 43 is lifted while the casing 431 is raised along the inclined surface 447 of the holding groove 445.

  When the damper device 43 is lifted, the teeth of the relay gear 42 that have been engaged with the teeth of the sect gear 41 until now are disengaged from the teeth of the sect gear 41 as shown in FIG. The operation is not transmitted to the buffering operation of the damper device 43 via the relay gear 42. Therefore, when opening the document reading device 30, the opening operation of the document reading device 30 is cut off from the buffering action of the damper device 43, so that the document reading device 30 is quickly opened.

  When closing the document reading device 30 once opened, the damper device 43 is lowered to the lower position L1 due to its own weight. Therefore, as described above, the document reading device 30 is closed. It is buffered by the damper device 43 and is closed gently.

  As described above in detail, the image forming apparatus 10 according to the present invention includes the apparatus main body 20 in which various members for image formation are installed, and the horizontal axis 34 provided at one edge of the upper portion of the apparatus main body 20. The apparatus main body 20 and the original document are provided with a document reading device 30 that changes the posture between the closed posture S1 and the open posture S2 with respect to the upper surface of the device main body 20 as a lid member by rotating forward and backward. A buffer mechanism 40 for buffering the opening / closing operation of the document reader 30 is interposed between the reader 30 and the reader 30.

  The buffer mechanism 40 protrudes from the document reading device 30 and enters the apparatus main body 20, and is provided in the sect gear 41 centering on the axis of the support shaft 34 and the apparatus main body 20, and Since the damper device 43 includes a relay gear 42 that meshes with the sect gear 41 and is rotatable around the damper shaft 432, and the holding member 44 that holds the damper device 43, the opened document reading device 30 is provided. When closing, this closing operation is performed by the damper gear 43 held by the holding member 44 positioned at the lower position L1 where the relay gear 42 meshes with the sect gear 41, and the relay gear meshed with the sect gear 41. Since the closing operation of the document reading device 30 is buffered by the buffering action of the damper device 43, the document reading device 30 is loosened. It is closed.

  On the other hand, when opening the document reading device 30 in the closed state, the damper device 43 located at the lower position L1 where the relay gear 42 meshes with the sect gear 41 causes the relay gear 42 to the sect gear 41 by this opening operation. Since the position is changed to the upper position L <b> 2 where the meshing is eliminated, the opening operation of the document reading device 30 is cut off from the damper device 43, whereby the document reading device 30 receives the buffering action of the damper device 43. Open easily and quickly.

  Then, the damper device 43 is guided to the holding member 44 that holds the damper device 43 to an upper position L2 where the engagement of the relay gear 42 with the sect gear 41 is released according to the opening operation of the document reading device 30, while the document reading device 30. By providing an inclined surface 447 that guides the damper device 43 to a lower position L1 where the relay gear 42 meshes with the sect gear 41 in accordance with the closing operation of this, the inclined surface 447 is a one-way clutch having a complicated structure conventionally employed. Since the structure can be made extremely simple in comparison, it is possible to achieve a reduction in the number of parts and the cost of parts as much as it is not necessary to provide an expensive one-way clutch.

  Further, the damper device 43 is provided with a casing 431 as a guided member guided by the inclined surface 447, while the holding member 44 is a casing in which the tooth surface of the relay gear 42 faces the tooth surface of the sect gear 41. Since the holding groove 445 for holding 431 is provided, the casing 431 of the damper device 43 is positioned at the groove bottom of the holding groove 445 of the holding member 44 when the document reading device 30 is closed, and the relay gear 42 is It meshes with the sect gear 41. When the document reading device 30 is opened in this state, the sect gear 41 rotates upward around the support shaft 34 at the lower position L1 with respect to the relay gear 42, whereby the relay gear 42 rotates in the opposite direction to the sect gear 41. However, the inclined surface 447 which is the groove wall facing the tooth surface of the sect gear 41 in the holding groove 445 and separated from the sect gear 41 is inclined upward from the arc groove 446 at the groove bottom. Therefore, the relay gear 42 that has received the transmission of the force from the sect gear 41 moves obliquely with the inclined surface 447 upward, and the meshing state with the sect gear 41 is thereby eliminated.

  When the tooth of the relay gear 42 is disengaged from the tooth of the sect gear by this movement, the relay gear 42 tries to descend by its own weight, but the tooth of the relay gear 42 is pushed up again by the next tooth of the sect gear 41. The relay gear 42 is always pushed up when the teeth facing the sect gear 41 collide with the teeth of the sect gear 41 and the teeth of the sect gear 41 that rises sequentially according to the rotation of the sect gear 41 around the support shaft 34. The damper device 43 including the gear 42 and the casing 431 does not return to the groove bottom of the holding groove 445 while the document reading device 30 is performing the opening operation, and the opening operation of the document reading device 30 is performed with the damper member. Will be cut off.

  On the other hand, when closing the document reading device 30 once opened, the sect gear 41 rotates around the support shaft 34 in the direction opposite to that when the document reading device 30 is opened and meshes with the relay gear 42. Since the teeth of the sect gear 41 are lowered, not only the upward force acts on the teeth of the relay gear 42 meshed with the sect gear 41, but the downward force acts on the casing 431. Due to its own weight and the weight of the damper device 43, it descends along the inclined surface 447 and reaches the arc groove 446. When the casing 431 reaches the groove bottom of the holding groove 445, the meshing state of the relay gear 42 and the sect gear 41 is ensured, and thereafter the rotation of the sect gear 41 around the support shaft 34 is performed via the relay gear 42 in the damper device. 43, whereby the closing operation of the document reading device 30 becomes gentle.

  In this way, the damper device 43 is provided with the casing 431 guided by the inclined surface 447, and the holding member 44 holds the casing 431 with the tooth surface of the relay gear 42 facing the tooth surface of the sect gear 41. By providing the groove 445 and forming the inclined surface 447 by the groove wall (that is, the inclined surface 447) facing the tooth surface of the sect gear 41 in the holding groove 445 and spaced from the sect gear 41, the document reading device 30. The buffer structure that works only when the document reader 30 is closed and does not act when the document reader 30 is opened can be made very simple.

  In addition, since the retaining groove 445 is provided with a retaining piece 448 for retaining the casing 431, even if the casing 431 repeatedly moves up and down in the retaining groove 445 due to the opening / closing operation of the document reading device 30, the casing 431 does not move. By being blocked by the retaining piece 448 provided in the holding groove 445, it is possible to reliably prevent the occurrence of inconveniences such as coming off the holding groove 445.

  The present invention is not limited to the above embodiment, and includes the following contents.

  (1) In the above embodiment, the document reading device 30 is employed as the lid member according to the present invention, but the present invention is not limited to the document reading device 30 being a lid member. The present invention can be applied to a paper discharge tray 12 provided in the apparatus body 20 so as to open and close by rotating forward and backward in the vertical direction around the axis, and various opening / closing lids provided in various places (not shown). it can.

  (2) In the above embodiment, the guide member according to the present invention is formed by the inclined surface 447 as the groove wall according to the present invention formed on the front support column 443 of the holding member 44. The guide member is not limited to the inclined surface 447. For example, the guide member is pivotally supported about a predetermined base end shaft and the tip end side is pivotally supported by the damper shaft 432. A moving arm may be provided, and the installation position may be set so that the swing arm is tilted in the direction of the tooth surface of the sect gear 41, and the relay gear 42 is engaged with the sect gear 41 in a state where the swing arm is tilted. . Even when such a swing arm is employed as a guide member, the sect gear 41 is in a state of cutting off the damper device 43 when the document reading device 30 is opened, while the document reading device 30 is closed when the document reading device 30 is closed. The closing operation of the device 30 is transmitted to the damper device 43 via the sect gear 41.

  (3) In the above embodiment, the left edge projection 205 and the right partition projection 206 are provided on the upper edge frame plate 201, and the relay gear 42 and the damper device 43 are pulled out left and right by the left and right partition projections 205, 206. However, instead of doing this, a pair of positioning projections 203 provided on the upper edge frame plate 201 side into which a positioning groove 434 recessed in the support base 433 of the damper device 43 is fitted. The height of the may be increased. By doing so, it is possible to prevent the damper device 43 from coming out of the holding groove 445 to the left and right without bothering the right and left screen protrusions 205 and 206.

  (4) In the above embodiment, the inclination angle of the inclined surface 447 is set to approximately 60 °, but the present invention is not limited to the inclined surface 447 being approximately 60 °. The angle may be less than 60 ° or may exceed 60 °.

  (5) In the above embodiment, the casing 431 of the damper device 43 is employed as the guided member according to the present invention. However, the present invention is a casing 431 in which the buffer member is loaded inside the guided member. It is not limited to a certain thing, You may employ | adopt the guide member for exclusive use as a separate body.

1A and 1B are diagrams illustrating an embodiment of an image forming apparatus according to the present invention, in which FIG. 1A is a perspective view of an appearance, and FIG. Shows a state in which the document reading device is set to the closed posture, and (C) shows a state in which the document reading device is set to the open posture. It is a fragmentary perspective view of the image forming apparatus for demonstrating a buffer mechanism. It is a perspective view which shows one Embodiment of a buffer mechanism, (A) has shown the state from which the damper apparatus was removed from the holding member, (B) has each shown the state with which the damper apparatus was mounted | worn to the holding member. It is an expansion perspective view which shows one Embodiment of a holding member. It is explanatory drawing of the side sectional view for demonstrating the effect | action of a buffer mechanism, (A) is the state in which the damper apparatus was set to the lower position, (B) was the damper apparatus being set to the upper position. Each state is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 11 Connection part 12 Paper discharge tray 20 Apparatus main body 201 Upper edge part frame board 202 Bowl-shaped edge dam 203 Positioning protrusion 204 Holding member mounting recessed part 205 Left screen protrusion 206 Right screen protrusion 209 Support frame 21 Lower exterior cover body 22 Photosensitive drum 23 Charging device 24 Exposure device 25 Developing device 26 Cleaning device 27 Fixing device 271 Fixing roller 272 Pressing roller 28 Paper cassette 29 Projection arm 30 Document reading device (lid member)
31 Upper exterior cover body 311 Operation table 32 Cover 33 Contact glass 34 Support shaft (horizontal shaft) 40 Buffer mechanism 41 Sect gear 42 Relay gear 422 Fork member 43 Damper device 431 Casing (guided member)
432 Damper shaft (gear shaft)
433 Support base 434 Positioning groove 44 Holding member 441 Base square 443 Front strut 444 Back strut 445 Holding groove 446 Arc groove 447 Inclined surface (groove wall) 448 Retaining stopper L1 Lower position (meshing position) L2 Upper position (retracted position)
P Paper S1 Closed posture S2 Opened posture

Claims (4)

An apparatus main body in which various members for image formation are installed, and a closed posture and an open posture with respect to the upper surface of the apparatus main body by rotating forward and backward around a horizontal axis provided at one edge of the upper portion of the apparatus main body. An image forming apparatus comprising a lid member whose posture is changed between
A buffer mechanism for buffering the opening and closing operation of the lid member is interposed between the apparatus main body and the lid member,
The buffer mechanism protrudes from the lid member and enters the apparatus main body, and a sect gear whose center of curvature is the axis of the support shaft;
A damper device provided in the device body and provided with a relay gear that meshes with the sect gear and is rotatable around a gear shaft;
A holding member for holding the damper device;
The holding member guides the damper device to a retracted position where the engagement of the relay gear with the sect gear is canceled according to the opening operation of the lid member, while the relay device is relayed to the relay device according to the closing operation of the lid member. An image forming apparatus comprising a guide member for guiding a gear to a meshing position where the gear meshes with the sect gear. The damper device has a guided member guided by the guide member,
The holding member has a holding groove for holding the guided member in a state where the tooth surface of the relay gear is opposed to the tooth surface of the sect gear,
The guide member is formed by a groove wall facing the tooth surface of the sect gear in the holding groove and spaced from the sect gear,
The image forming apparatus according to claim 1, wherein the groove wall is inclined upward from the groove bottom.   The image forming apparatus according to claim 2, wherein the holding groove is provided with a retaining piece for retaining the guided member.   4. The image forming apparatus according to claim 1, wherein the lid member is an original reading apparatus that reads an image of an original and transmits the read image to an exposure apparatus built in the apparatus main body. 5.

Images