JP2007310134A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To securely prevent excessive supply of toner without using a level sensor that detects quantity of toner in the main body of the developing device. <P>SOLUTION: The developing device 20 used for a printer 10 includes: a main body 30 of the developing device, which has a developing roller 34 for supplying toner to a photoreceptor drum 131 by rotating around its axis; a toner cartridge 40, which has a supply roller 43 for supplying toner to the main body 30 of the developing device by rotating around its axis; and a switching mechanism 50 for mechanically switching the supply roller 43 between stop and rotation according as whether or not the quantity of toner in the main body 30 of the developing device 30 has reached the upper limit level L set in advance. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  In the present invention, a developer image along the electrostatic latent image is formed on the image carrier by supplying a developer from the developing device to the image carrier on which the electrostatic latent image is formed. The present invention relates to a copying machine, a facsimile machine, and an image forming apparatus such as a printer configured to transfer to a transfer material.

  Usually, image forming apparatuses such as copying machines, facsimile machines, and printers supply developer from a developing device to, for example, a photosensitive drum as an image carrier on which an electrostatic latent image is formed based on predetermined image information. As a result, a developer image along the electrostatic latent image is formed on the image carrier, and the developer image is transferred to a sheet (transfer material). A developing device used in such an image forming apparatus is generally composed of a developing device main body and a detachable toner cartridge for supplying toner (developer) to the developing device main body.

  The toner cartridge and the developing device main body are respectively provided with a supply opening and a receiving opening for supplying toner in the toner cartridge into the developing device main body. Then, when the toner cartridge is mounted on the developing device main body, the lids that have closed these openings are opened, whereby the toner in the toner cartridge is replenished into the developing device main body through the openings. To get.

  The developing device main body includes a screw feeder as a pair of agitating and conveying members arranged in parallel to each other, and toner that is being circulated and conveyed in the developing device main body while being agitated by driving rotation around the axis of the pair of screw feeders. And a developing roller for supplying a part to the peripheral surface of the photosensitive drum.

  On the other hand, the toner cartridge includes a stirring member that stirs the toner inside, and a replenishing roller that feeds the toner being stirred toward the delivery opening. Accordingly, the toner cartridge is mounted on the developing device main body, and the agitating member and the replenishing roller of the toner cartridge are operated by driving a predetermined drive motor in a state where the lid is opened, so that the toner in the toner cartridge The developing device main body is supplied through the receiving opening.

  By the way, if the replenishing roller of the toner cartridge continues to be driven even though the inside of the developing device is full of toner, the toner is pushed from the toner cartridge into the developing device. There is a problem that the toner in the apparatus is excessively pressed and cannot be properly circulated and conveyed, or the toner aggregates and cannot be properly supplied to the photosensitive drum. In order to solve this inconvenience, a level sensor for detecting the toner level in the developing device main body is provided, and when the level sensor detects a predetermined level, control is performed to stop the driving of the stirring member and the replenishing roller of the toner cartridge. It is common.

  However, when such control is performed, it is necessary to provide a level sensor and a control means, which raises a problem that component costs and design costs increase.

  Therefore, for example, a developing device described in Patent Document 1 is known as a structure that appropriately circulates and moves toner in the developing device main body without providing a level sensor. The developing device described in Patent Document 1 is provided with a specific region in which the toner transport capability is locally reduced on the downstream side of the toner receiving region below the receiving opening in the developing device body. In this specific area, the conveying capacity is reduced by reducing the diameter of the conveying screw of the conveying means.

  By adopting such a configuration, regardless of the amount of toner in the developing device main body, the toner is always clogged in a specific area. Therefore, the clogged toner further causes the toner cartridge to enter the developing device main body. Excess toner is prevented from being supplied, and a level sensor need not be employed.

  However, if a specific area where the diameter of the conveying screw is smaller than the other is provided, the toner remains in a tunnel shape in the specific area, which may cause inconvenience that the toner cannot be used up to the end.

  In addition, when toner is supplied from the toner cartridge into the developing device main body at the initial stage where no toner is loaded, the supplied toner stays in a specific area and is circulated and conveyed through the developing device main body. Therefore, the developing device cannot be used for a long time until the circulation and conveyance is performed, and there is a disadvantage that it is not quick.

In order to solve such inconvenience, a developing device as described in Patent Document 2 has been proposed. In this developing device, the toner is applied to a specific area by appropriately setting the length dimension and conveying capacity of two conveying screws arranged in parallel in the developing device main body so as to satisfy predetermined conditions. The toner is circulated so that excessive toner supply from the toner cartridge to the developing device main body is suppressed, and the toner is properly circulated and conveyed in the developing device main body.
JP 2001-235933 A JP 2004-151340 A

  However, as described in Patent Document 2, the length dimension and the conveying capacity of two conveying screws arranged in parallel in the developing device main body are appropriately set so as to satisfy predetermined conditions. Thus, excessive toner supply to the developing device main body can be achieved even if the toner is properly circulated and conveyed in the developing device main body while suppressing excessive toner supply from the toner cartridge to the developing device main body. Since the supply is suppressed only by the toner staying in the specific area, the toner in the specific area is always pressed by the toner from the toner cartridge as long as the stirring member and the replenishing roller in the toner cartridge are driven. Therefore, for example, if the toner staying in a specific area is agglomerated and transported all at once, the toner is excessively supplied into the developing device main unit. There is a possibility of occurrence of inconvenience that is.

  The present invention has been made in view of such a conventional situation, and it is possible to reliably prevent excessive toner supply on the assumption that a level sensor for detecting the amount of toner in the developing device main body is not employed. An object of the present invention is to provide an image forming apparatus having the developing device.

  According to the first aspect of the present invention, a developer image along the electrostatic latent image is formed on the image carrier by supplying the developer from the developing device to the image carrier on which the electrostatic latent image is formed. In the image forming apparatus configured to transfer the developer image to the transfer material, the developing device includes a developing device main body including a developing roller that supplies the developer to the image carrier by rotation around an axis. The developer supply container having a supply roller for supplying developer to the developing device main body by rotation around the axis, and whether or not the developer amount in the developing device main body reaches a predetermined storage amount And a switching mechanism that mechanically switches the supply roller between stop and rotation.

  According to this configuration, in the image forming apparatus, the developer is supplied from the developing device to the image carrier on which the electrostatic latent image is formed by the rotation of the developing roller about the axis, thereby causing the electrostatic latent image on the image carrier. A developer image along is formed. The developer image formed on the image carrier is transferred to a transfer material, whereby a developer image is formed on the transfer material.

  The developing device includes a developing device main body having a developing roller, a developer replenishing container having a replenishing roller for replenishing the developer to the developing device main body, and a replenishing roller according to the amount of developer in the developing device main body. Since a switching mechanism that mechanically switches between rotation and stop is provided, by setting a developer amount (predetermined storage amount) in the developing device body in which the switching mechanism performs a switching operation in advance, The replenishing roller rotates until the inside of the developing device main body reaches a predetermined storage amount, whereby the developer in the developer replenishing container is supplied into the developing device main body.

  When the developer in the developing device main body reaches a predetermined storage amount, the switching mechanism mechanically operates to stop the replenishing roller, so that the developer replenishment from the developer replenishing container to the developing device main body is not performed. No longer done.

  In this way, by providing a switching mechanism that mechanically switches the supply roller of the developer supply container between stop and rotation depending on whether or not the developer amount in the developing device main body has reached a predetermined storage amount, There is no need to provide a level sensor for detecting the amount of developer stored in the developing device main body as in the prior art, and there is no need to perform electrical control, and a portion for retaining the developer is provided in the developing device main body. Compared to the case, the supply of the developer from the developer supply container to the developing device main body is reliably prevented in a state where the developer in the developing device main body reaches a predetermined storage amount.

  According to a second aspect of the present invention, in the first aspect of the invention, the switching mechanism rotates around the support shaft in a state where the developer amount in the developing device main body does not reach the predetermined storage amount. A rotation plate to be obtained, a switching lever for changing the posture between an allowable posture for allowing rotation of the replenishing roller by rotating integrally with the rotation plate and a regulating posture for restricting rotation of the replenishing roller, and the switching The replenishment of the driving force from the drive means is transmitted with the switching lever set to the restricting posture while the lever is transmitted to the replenishing roller while the lever is set to the allowable posture. And a clutch mechanism for interrupting transmission to the roller.

  According to such a configuration, in a state where the developer loaded in the developing device main body does not reach the predetermined storage amount, the switching lever is set to an allowable posture that allows the replenishment roller to rotate. The developer in the developer supply container is supplied into the developing device main body by driving rotation of the supply roller.

  As a result, the rotating plate is pushed by the developer as the amount of developer in the developing device increases and rotates around the support shaft, and the switching lever integrated with the rotating plate also rotates simultaneously. When the developer in the main body of the developing device reaches a predetermined storage amount, the switching lever is changed to a restricting posture, whereby the clutch mechanism blocks transmission of driving force from the driving means to the replenishing roller. The supply of the developer from the developer supply container into the developing device main body is interrupted. Accordingly, it is possible to prevent the developer from becoming excessive in the developing device main body.

  When the developer in the main body of the developing device is consumed and becomes less than the predetermined storage amount, the pressing force of the toner against the rotating plate is reduced, thereby supporting the switching lever integrated with the rotating plate. The posture is changed from the restricted posture to the allowable posture by rotating around the axis in the opposite direction. This causes the clutch mechanism to transmit the driving force from the driving means to the replenishing roller, so that the developer is supplied from the developer replenishing container to the developing device main body.

  As described above, the switching lever rotates forward and backward through the rotating plate according to the amount of the developer in the developing device main body, and thereby the clutch mechanism by the posture change between the allowable posture and the restricting posture of the switching lever. The replenishing roller is driven to rotate or stop by the action of the above, so that the level of the developer in the conventional developing device main body is detected by the level sensor, and based on this detection signal, The switching mechanism is simpler than the method of controlling the supply of developer.

  According to a third aspect of the present invention, in the second aspect of the present invention, the replenishing roller is provided with a roller side gear that is concentric with the replenishing roller and can rotate integrally therewith, while the developer replenishing container includes The first relay gear to which the driving force of the driving means is transmitted and the first relay gear are concentrically opposed to each other, are meshed with the roller side gear, and are rotated by a switching lever set in the restriction posture. A second relay gear to be blocked, and the clutch mechanism is interposed between the first and second relay gears, and the second relay gear drives the rotation of the first relay gear by a frictional force generated by an urging force. On the other hand, there is provided a spring clutch that prevents the rotation of the first relay gear from being transmitted to the second relay gear while the rotation of the second relay gear is blocked.

  According to such a configuration, when the developer in the developing device main body has not reached the predetermined storage amount, the switching lever is set to the allowable posture, so that the second relay gear is prevented from rotating by the switching lever. Therefore, the drive rotation of the first relay gear is transmitted to the roller side gear via the spring clutch and the second relay gear, and the developer in the developer supply container is developed by the rotation of the supply roller thereby. Supplied in the apparatus body.

  On the other hand, when the developer in the developing device main body reaches a predetermined storage amount, the switching lever is changed from the allowable posture to the restricting posture and the rotation of the second relay gear is prevented. Even if is driven to rotate, the spring clutch slips and the second relay gear does not rotate. Accordingly, the roller side gear meshing with the second relay gear does not rotate, and the developer in the developer supply container is not supplied into the developing device main body.

  In this way, the first relay gear to which the driving force of the driving means is transmitted, and the first relay gear are concentrically opposed to each other and rotated by the switching lever that meshes with the roller side gear and is set in the restriction posture. By interposing a spring clutch between the second relay gear and the second relay gear, the rotation of the roller side gear, that is, the replenishment roller is prevented in a state where the developer in the developing device main body reaches a predetermined storage amount. The structure becomes simple.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the developer is composed only of a toner that is a colorant.

  In general, there are two types of developers: a one-component system consisting only of toner as a colorant, and a two-component system consisting of a mixture of toner and a carrier for giving charge to the toner. In the case of a two-component developer, only toner is supplied from the developing device to the image carrier, and the carrier remains in the developing device main body. Therefore, even if the toner is consumed, the volume of the developer in the developing device main body is not reduced so much by the remaining carrier, so that it is difficult to secure a space in which the rotating plate can be rotated in the developing device main body. The plate cannot be rotated with good detection accuracy with good toner reduction.

  On the other hand, when the developer is of a one-component type only with toner (claim 4), since the decrease in toner leads to the rotation of the rotating plate, high detection accuracy for the decrease in toner is obtained. It is done. Therefore, in the case where the developer is constituted only by the toner that is the colorant, when the developer in the developing device main body reaches a predetermined storage amount, the developer from the developer supply container to the developing device main body. It is suitable for preventing the supply of.

  According to the first aspect of the present invention, the switching for mechanically switching the supply roller of the developer supply container between the stop and the rotation depending on whether or not the amount of developer in the developing device main body has reached a predetermined storage amount. Since the mechanism is provided, there is no need to provide a level sensor for detecting the amount of developer stored in the developing device body as in the prior art, and there is no need for electrical control, as well as partial development in the developing device body. As compared with the case where a portion for retaining the developer is provided, the supply of the developer from the developer supply container to the developing device main body is reliably prevented in a state where the developer in the developing device main body reaches a predetermined storage amount. Can do. Therefore, the developer that has been excessively replenished in the main body of the developing device aggregates, whereby it becomes impossible to properly supply the developer to the image carrier, resulting in inconveniences such as image defects. It is cheap and can be reliably prevented.

  According to the second aspect of the present invention, the switching lever rotates forward and backward via the rotating plate according to the amount of the developer in the developing device main body, so that the switching lever can move between the allowable posture and the restricting posture. Since the replenishing roller is driven to rotate or stop by the action of the clutch mechanism by changing the posture of the developer, the level of the developer in the conventional developing device main body is detected by a level sensor and based on this detection signal The switching mechanism can be simplified as compared with the method of controlling the supply of the developer into the developing device main body.

  According to the third aspect of the present invention, the first relay gear to which the driving force of the driving means is transmitted is concentrically opposed to the first relay gear, meshed with the roller side gear, and set in a restricted posture. The roller side gear, that is, replenishment in a state where the developer in the main body of the developing device reaches a predetermined storage amount by interposing a spring clutch between the second relay gear whose rotation is prevented by the switching lever The structure for preventing the rotation of the roller can be simplified.

  According to the fourth aspect of the present invention, when the developer is of a one-component type only with toner, the reduction of the toner leads to securing the rotation space of the immediate rotation plate, and the high detection accuracy with respect to the reduction of the toner is achieved. Therefore, when the developer is composed only of the toner that is the colorant, the developer in the main body of the developing device has a predetermined amount as compared with the case where the developer is composed of the toner and the carrier. This is effective for preventing the supply of the developer from the developer supply container to the developing device main body when the storage amount is reached.

  FIG. 1 is a side sectional view showing an embodiment of a printer 10 according to the present invention. As shown in this figure, a printer (image forming apparatus) 10 is fed out from a sheet storage unit 12 that stores a sheet (transfer material) P to be subjected to printing processing, and a sheet bundle P1 stored in the sheet storage unit 12. The image forming unit 13 that performs an image forming process on each of the sheets P and a fixing unit 14 that performs a fixing process on the sheet P that has been transferred by the image forming unit 13 include an apparatus main body. 11, and a paper discharge unit 15 for discharging the paper P subjected to fixing processing by the fixing unit 14 is provided at the top of the apparatus main body 11.

  A predetermined number (one in this embodiment) of paper cassettes 121 is provided in the paper storage unit 12 so as to be detachable from the apparatus main body 11. A pickup roller 122 is provided at the upstream end (right side in FIG. 1) of the paper cassette 121 to feed out the paper P one by one from the paper bundle P1. The paper P fed out of the paper cassette 121 by driving the pickup roller 122 is supplied to the image forming unit 13 through the paper feed conveyance path 123 and the registration roller pair 124 provided at the downstream end of the paper feed conveyance path 123. It is supposed to be paper.

  The image forming unit 13 performs a transfer process on the paper P based on image information transmitted from a computer or the like, and is provided so as to be rotatable around a drum core extending in the front-rear direction (a direction perpendicular to the paper surface of FIG. 1). The charger 132, the exposure device 133, the developing device 20, the transfer roller 134, and the cleaning device are arranged in the clockwise direction from the position directly above the photosensitive drum 131 along the peripheral surface of the photosensitive drum (image carrier) 131. It is formed by disposing the device 135.

  The photosensitive drum 131 is for forming an electrostatic latent image on the peripheral surface and a toner image (developer image) along the electrostatic latent image. The photosensitive drum 131 is flat and strong on the peripheral surface. A silicon layer is laminated, which makes it suitable for forming these images.

  The charger 132 forms a uniform charge on the peripheral surface of the photosensitive drum 131 rotating in the clockwise direction around the drum core. In the example shown in FIG. A method of applying a charge to the peripheral surface is adopted. A charging roller that applies a charge while rotating the driven surface while contacting the peripheral surface of the photosensitive drum 131 is used instead of the charger 132 as a member that applies a charge to the peripheral surface of the photosensitive drum 131. Also good.

  The exposure device 133 irradiates the peripheral surface of the rotating photosensitive drum 131 with a laser beam to which intensity is applied based on image data transmitted from an external device such as a computer, and thereby the photosensitive drum 131 is irradiated with the laser beam. An electrostatic latent image is formed on the peripheral surface of the photosensitive drum 131 by erasing the charge on the peripheral surface irradiated with the laser beam.

  The developing device 20 supplies toner to the peripheral surface of the photosensitive drum 131 to attach the toner to a portion where the electrostatic latent image is formed on the peripheral surface. Is formed. The developing device 20 will be described in detail later with reference to FIGS.

  The transfer roller 134 transfers a positively charged toner image formed on the peripheral surface of the photosensitive drum 131 to the paper P with respect to the paper P sent to a position immediately below the photosensitive drum 131. A negative charge having a polarity opposite to that of the toner image is applied to the paper P.

  Accordingly, the paper P that has reached the position immediately below the photosensitive drum 131 is pressed and held between the transfer roller 134 and the photosensitive drum 131, and the toner image on the circumferential surface of the photosensitive drum 131 that is positively charged is negatively charged. The sheet P is peeled off toward the surface of P, whereby the transfer process is performed on the sheet P.

  The cleaning device 135 is for removing the toner remaining on the peripheral surface of the photosensitive drum 131 after the transfer process and cleaning it. The peripheral surface of the photosensitive drum 131 cleaned by the cleaning device 135 goes to the charger 132 again for the next image forming process.

  The fixing unit 14 performs a fixing process by heating the toner image of the paper P subjected to the transfer process by the image forming unit 13. The fixing roller 141 applies heat to the paper P, and a lower part of the fixing roller 141. And a pressure roller 142 arranged opposite to each other. Then, the sheet P after the transfer process is fed toward the nip portion N formed between the fixing roller 141 and the pressure roller 142 and passes through the nip portion N, so that the heat from the fixing roller 141 is transferred. And the fixing process is performed. The paper P subjected to the fixing process is discharged to the paper discharge unit 15 through the paper discharge conveyance path 143.

  The paper discharge unit 15 is formed by recessing the top of the apparatus main body 11, and a paper discharge tray 151 for receiving the discharged paper P is formed at the bottom of the concave portion.

  2 and 3 are partially cutaway perspective views showing an embodiment of the developing device 20, FIG. 2 is a state in which the switching mechanism 50 is disassembled, and FIG. 3 is a state in which the switching mechanism 50 is assembled. Respectively. 4 is a cross-sectional view taken along the line I-I of FIG. 3 (however, the drive motor 21, drive gear 22, second relay gear 52, latch gear 53, switching lever 553, and torsion spring 554 are left side views). FIG. 4A shows a state in which the switching lever 553 is set to the allowable posture S1, and FIG. 4B shows a state in which the switching lever 553 is set to the restricting posture S2. 2 to 4, 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 leftward, the + X direction is rightward, the -Y direction is frontward, and the + Y direction is rearward. That's it.

  As shown in these drawings, the developing device 20 includes a developing device main body 30 that is provided immediately adjacent to the photosensitive drum 131 and a developing device main body 30 that is detachably mounted on the developing device main body 30. A toner cartridge (developer supply container) 40 for supplying a developer (toner in this embodiment) to 30 and a developing device main body 30 and the toner cartridge 40 are interposed between the developing device main body 30 and the toner cartridge 40 and the toner in the toner cartridge 40 is removed from the developing device. It has a basic configuration including a switching mechanism 50 that mechanically switches between a state in which the main body 30 can be supplied and a state in which the supply is stopped.

Incidentally, the developer includes a so-called one-component system composed only of toner and a so-called two-component system composed of toner and carrier. The toner is a fine powder having a particle diameter of 6 to 12 μm in which additives such as a colorant, a charge control agent and wax are dispersed in a binder resin. On the other hand, the carrier is magnetic particles having a particle size of 60 to 200 μm such as magnetite (Fe ₃ O ₄ ), and is used for charging the toner. The toner is a consumable that is appropriately replenished from the toner cartridge 40 to the developing device 20, whereas a predetermined amount of the carrier is loaded in the developing device 20 in advance and is circulated and used without being consumed. It is common. In this embodiment, a one-component developer composed only of toner is used as the developer.

  In the developing device main body 30, a first screw feeder 32, a second screw feeder 33, and a developing roller 34 that extend in the left-right direction are arranged in parallel in a box-shaped main body side casing 31 from the rear to the front. Is made up of.

  A receiving opening 311 (FIG. 4) for receiving the toner in the toner cartridge 40 into the main body side casing 31 is provided immediately above the first screw feeder 32 on the top plate of the main body side casing 31. A toner supply opening 312 (FIG. 4) for supplying toner, which is opened over substantially the entire length in the left-right direction of the main body side casing 31, to the photosensitive drum 131 is opened on the front surface of the side casing 31.

  Then, the toner introduced from the toner cartridge 40 through the receiving opening 311 circulates in the main body side casing 31 while being stirred by the driving rotation of the first and second screw feeders 32 and 33, and a part of the toner is driven. The toner is supplied to the peripheral surface of the photosensitive drum 131 through the peripheral surface of the developing roller 34 that is rotating.

  As shown in FIG. 4, a layer thickness regulating blade 35 having a lower end edge facing the peripheral surface of the developing roller 34 is provided at the upper portion of the toner supply opening 312, and is anticlockwise around the axis of the developing roller 34. The toner supplied toward the photosensitive drum 131 by the peripheral surface of the developing roller 34 by turning toward the photosensitive drum 131 passes through a gap between the layer thickness regulating blade 35 and the peripheral surface of the developing roller 34 to have a predetermined layer pressure. It is made to become.

  The first and second screw feeders 32 and 33 and the developing roller 34 all transmit the driving force of a driving motor (not shown) through a gear mechanism (not shown) provided on the right side surface of the main body side casing 31. As a result, synchronous rotation is performed.

  The toner cartridge 40 is for replenishing toner into the developing device main body 30 according to the amount of toner inside, and is detachably mounted on the developing device main body 30. The toner cartridge 40 includes a screw feeder 42 extending in the left-right direction in a box-shaped cartridge-side casing 41 having a funnel-shaped lower portion in side view, and a replenishing roller extending in the left-right direction, which is substantially the same length as the screw feeder 42. 43.

  The screw feeder 42 is provided between the funnel-shaped portions of the left and right side walls 411 in the cartridge-side casing 41, and is laid on a portion slightly rearward from the central portion in the front-rear direction. The screw feeder 42 includes a screw shaft 421 and spiral fins 422 formed concentrically on the circumferential surface of the screw shaft 421 and continuously formed at the same pitch.

  In such a screw feeder 42, the driving force of a driving motor (driving means) 21 provided at an appropriate position in the apparatus main body 11 of the printer 10 is determined by the predetermined gear mechanism 211 and the cartridge side casing 41 in the apparatus main body 11. Is transmitted via a drive gear 22 provided at the lower left rear position of the first surface and a first relay gear 51 which will be described later, so that it can be driven and rotated about the screw shaft 421.

  The replenishing roller 43 is a lower portion between the funnel-shaped portions of the left and right side walls 411 in the cartridge side casing 41, and is installed in the center in the front-rear direction, thereby being juxtaposed at the front position of the screw feeder 42. It is in a state.

  The replenishing roller 43 includes a roller shaft 431 penetrating between a pair of side walls 411 of the cartridge side casing 41 and a replenishing roller body 432 that is concentrically and externally fitted to the roller shaft 431 so as to be integrally rotatable. .

  Such a replenishment roller 43 has a driving force of the drive motor 21 such that the gear mechanism 211, the drive gear 22, the first relay gear 51, a spring clutch (clutch mechanism) 54 described later, and a second clutch described later. It is transmitted via a replenishing roller side gear (roller side gear) 44 that meshes with the relay gear 52 and the second relay gear 52 and is externally fitted to the roller shaft 431 so as to be integrally rotatable. The roller shaft 431 can be driven to rotate.

  Therefore, when the drive motor 21 is driven, this driving force is transmitted to the screw feeder 42 via the gear mechanism 211, the drive gear 22 and the first relay gear 51, and the rotation of the first relay gear 51 is This is transmitted to the supply roller 43 via the spring clutch 54, the second relay gear 52, and the supply roller side gear 44, whereby the screw feeder 42 and the supply roller 43 rotate synchronously at the same time.

  At the bottom of the cartridge-side casing 41, a lead-out opening 433 (see FIG. 4) for leading the toner in the cartridge-side casing 41 into the main body-side casing 31 on the left side of the position facing the supply roller 43. The toner being conveyed while being agitated in the toner cartridge 40 by simultaneous driving of the screw feeder 42 and the replenishing roller 43 passes through the outlet opening 433 and the receiving opening 311 of the developing device main body 30 on the main body side. The casing 31 is replenished.

  The switching mechanism 50 is in a state in which the toner stored in the main body side casing 31 of the developing device main body 30 has not reached a preset upper limit level (predetermined storage amount) L (FIG. 4B). The operation of the replenishing roller 43 is switched so that the driving of the replenishing roller 43 is stopped when the toner reaches the upper limit level L.

  The switching mechanism 50 includes a first relay gear 51 that is concentrically and externally fitted to the screw shaft 421 of the screw feeder 42 and has a diameter dimension set so as to mesh with the drive gear 22. A second relay gear 52 that is concentrically fitted to the screw shaft 421 on the left side of the first relay gear 51 so as to be relatively rotatable, and a latch that is concentrically fixed to the left surface of the second relay gear 52 so as to be integrally rotatable. A spring clutch 54 interposed between the gear 53, the second relay gear 52, and the first relay gear 51 and concentrically mounted on the roller shaft 431 so as to be relatively rotatable; And a rotation adjusting member 55 for allowing or stopping rotation of the latch gear 53 by rotating forward and backward around a support shaft 551 described later according to the amount of toner.

  In the present embodiment, the first relay gear 51 and the second relay gear 52 are set to have the same diameter, whereas the latch gear 53 is set to be slightly smaller in diameter than the second relay gear 52. . A plurality of latches 531 are projected from the peripheral surface of the latch gear 53 at an equal pitch in the circumferential direction.

  The spring clutch 54 is formed of a spring plate, and has a spring disc 541 having a smaller diameter than the first relay gear 51 having a center hole fitted around the screw shaft 421, and a periphery from the periphery of the spring disc 541. And a plurality of clutch pieces 542 projecting outward at equal pitches in the direction. Each clutch piece 542 is set to have the same protruding amount from the spring disk 541 and has a predetermined angle toward the first relay gear 51 (approximately 30 ° with respect to the spring disk 541 in the present embodiment). It is bent.

  The spring clutch 54 is fitted on the screw shaft 421 after the first relay gear 51 is fitted to the back of the screw shaft 421. Subsequently, the second relay gear 52 and the latch gear 53 are externally fitted to the screw shaft 421, and the spring clutch 54 is pressed and clamped between the first and second relay gears 51, 52, and then the externally connected from the latch gear 53 of the screw shaft 421. A retaining member such as a cap nut 45 (FIG. 3) is attached to the protruding portion, and thereby the urging force of the spring clutch 54 is secured.

  In a state where the spring clutch 54 is mounted on the screw shaft 421, the clutch pieces 542 are pressed and clamped by the first and second relay gears 51 and 52 so that the amount of protrusion toward the right is reduced. The front end portion of each clutch piece 542 presses and abuts on the left surface of the first relay gear 51 with the urging force thereby, and the left surface of the spring disc 541 presses and abuts on the right surface of the second relay gear 52. Usually, the second relay gear 52 rotates integrally with the first relay gear 51 around the screw shaft 421 by the frictional force generated by this pressing contact.

  Due to this integral rotation, the replenishing roller side gear 44 meshing with the second relay gear 52 rotates around the roller shaft 431, whereby the replenishing roller 43 rotates. The toner is introduced into the main body side casing 31 through the lead-out opening 433 (FIG. 4) and the receiving opening 311.

  When the rotation of the latch gear 53 is blocked by the predetermined operation of the rotation adjusting member 55, the rotational force of the first relay gear 51 is greater than the frictional force of the spring clutch 54. Since the rotation is in sliding contact with the spring clutch 54, this rotation is not transmitted to the second relay gear 52.

  The rotation adjusting member 55 includes a support shaft 551 installed between the pair of side plates 313 along the rear plate 314 at a substantially central portion in the vertical direction of the main body side casing 31, and this support in the main body side casing 31. A rotating plate 552 that protrudes downward in the radial direction from the shaft 551, and a portion that protrudes outward from the left side plate 313 in the support shaft 551 so as to go in the opposite direction to the rotating plate 552. The switching lever 553 includes a torsion spring 554 that urges the rotating plate 552 and the switching lever 553 around the support shaft 551 in the clockwise direction.

  The rear plate 314 is provided with a bulging portion 315 extending outward in the left-right direction and bulging outward, and the support shaft 551 has the bulging portion 315 as shown in FIG. It is fitted in a sliding contact state in a long concave portion provided in the back side. By doing so, the toner is prevented from entering the space (rotating plate movable space V) between the rotating plate 552 and the rear plate 314 from the upper part of the support shaft 551.

  Further, the bottom plate 316 of the main body side casing 31 has an arcuate surface 316a with which the top edge of the rotating plate 552 is slidably contacted with the upper surface of the rear portion thereof centered on the axis of the support shaft 551. Further, a protruding edge portion 552a is provided at the lower end edge of the rotating plate 552 so as to protrude rearward from the arcuate surface 316a by a slight amount and extend over the entire length in the left-right direction. It has been. As a result, it is possible to effectively prevent the toner from entering the rotary plate movable space V from between the front end edge of the rotary plate 552 and the circular arc surface 316a.

  Further, the rotation plate 552 is set so that the length dimension in the left-right direction can come into sliding contact with the opposing surfaces of the pair of side plates 313, whereby the toner in the main body side casing 31 is transferred to the side edge of the rotation plate 552. It is possible to effectively prevent the rotation plate movable space V from entering between the surface and the inner surface of the side plate 313.

  The switching lever 553 is in a state in which the protruding edge portion 552a of the rotating plate 552 is positioned at the foremost position on the arc surface 316a in the rotating plate movable space V (allowable posture in which the switching lever 553 allows the replenishing roller 43 to rotate). A state in which the posture is set to S1 (FIG. 4A) and a state in which the toner is replenished counterclockwise by a predetermined amount (specifically, the toner is replenished into the main body side casing 31 so that the upper surface of the toner When the upper limit level L is reached and the rotation plate 552 is pushed by such toner and rotates by a predetermined amount, the switching lever 553 is set in the restriction posture S2 for restricting the rotation of the replenishing roller 43 (see FIG. 4 (B))), the length and the installation phase with respect to the rotary plate 552 are set so that the upper end of the switching lever 553 comes into contact with the lower surface of the latch 531 which is inclined obliquely backward with the leading end of the latch gear 53. It has been set.

  The switching lever 553 is provided with a stopper (not shown) at an appropriate position on the main body side casing 31 so that the switching lever 553 can be rotated around the support shaft 551 only between the allowable posture S1 and the regulating posture S2. Further, as the torsion spring 554, one having an elastic force smaller than the pressing force of the toner against the rotating plate 552 in a state where the upper surface of the toner reaches the upper limit level L is employed.

  According to the switching mechanism 50 configured as described above, the toner pressure is applied to the rotating plate 552 as shown in FIG. 4A when the toner is not stored in the main body side casing 31. Therefore, the projecting edge portion 552a of the rotating plate 552 is positioned at the forefront position of the arc surface 316a in the rotating plate movable space V by the biasing force of the torsion spring 554, whereby the switching lever 553 is moved to the allowable posture S1. The posture is set.

  When the switching lever 553 is set to the allowable posture S1, the upper end portion of the switching lever 553 is disengaged from the latch 531 of the latch gear 53, so that the latch gear 53 can rotate around the screw shaft 421. It has become. Therefore, when the drive motor 21 is driven in this state, this driving force is transmitted through the gear mechanism 211, the drive gear 22, the first relay gear 51, the spring clutch 54, the second relay gear 52, and the replenishing roller side gear 44. The toner in the cartridge side casing 41 is replenished into the main body side casing 31 via the lead-out opening 433 and the receiving opening 311 by the integral rotation of the replenishing roller main body 432 around the roller shaft 431. .

  When the toner level in the main body side casing 31 is increased by the replenishment of the toner, the rotating plate 552 is pressed by the pressure of the toner, and thereby the support shaft 551 resists the biasing force of the torsion spring 554. It starts to turn counterclockwise around.

  Then, when the toner level in the main body side casing 31 reaches the upper limit level L, the rotating plate 552 receives the pressing force of the upper limit level L toner and rotates the support plate 551 around the support shaft 551 in the counterclockwise direction a maximum amount. As a result, the switching lever 553, which has been in the allowable posture S1, is changed to the restricted posture S2, as shown in FIG. 4B. Since the upper end of the switching lever 553 is engaged with the latch 531 of the latch gear 53 by this posture change, the rotation of the latch gear 53 is restricted.

  Therefore, the rotation of the first relay gear 51 by the drive motor 21 is not transmitted to the second relay gear 52 because the spring clutch 54 slides on the left surface of the first relay gear 51 and the right surface of the second relay gear 52. Therefore, the replenishing roller 43 does not rotate, so that the toner in the cartridge side casing 41 is not supplied into the main body side casing 31.

  In this state, when the toner in the main body side casing 31 is consumed and decreased, the toner is moved to the regulation posture S2 by the clockwise rotation around the support shaft 551 of the rotation plate 552 due to the decrease in the pressing force of the toner. Since the switching lever 553 whose posture has been set returns to the allowable posture S1 and the upper end of the switching lever 553 is disengaged from the latch 531 of the latch gear 53, the second relay gear 52 resumes rotation, whereby the replenishment roller 43 rotates. Thus, the toner in the cartridge side casing 41 is replenished into the main body side casing 31.

  As described above, when the switching lever 553 changes the posture between the regulation posture S2 and the allowable posture S1 in accordance with the increase or decrease of the toner amount in the main body side casing 31, the toner amount in the main body side casing 31 is in an appropriate range. Therefore, the toner is pushed from the cartridge side casing 41 into the main body side casing 31 by the driving of the replenishing roller 43 even though the main body side casing 31 is full of toner. The toner in the side casing 31 is agglomerated, so that it is not possible to properly supply the toner to the photosensitive drum 131, and it is possible to effectively prevent the occurrence of inconveniences such as image defects.

  As described above in detail, the printer 10 according to the present invention supplies toner from the developing device 20 to the photosensitive drum 131 on which the electrostatic latent image is formed, so that the photosensitive drum 131 is aligned with the electrostatic latent image. Since the toner image is formed and this toner image is transferred to the paper P, the developing device 20 rotates to the photosensitive drum 131 on which the electrostatic latent image is formed by the rotation of the developing roller 34 around the axis. By supplying the toner, a toner image along the electrostatic latent image is formed on the photosensitive drum 131. The toner image formed on the photosensitive drum 131 is transferred to the paper P, so that the toner image is transferred to the paper P.

  The developing device 20 applied to the printer 10 includes a developing device main body 30 including a developing roller 34 that supplies toner to the photosensitive drum 131 by rotation around an axis, and the developing device main body 30 supplies toner around the axis. The toner cartridge 40 having the replenishing roller 43 to be replenished by rotation and whether the toner amount in the developing device main body 30 has reached the preset upper limit level L or not are stopped and rotated. Since the switching mechanism 50 is provided with the switching mechanism 50 in advance, the toner amount (upper limit level L) in the developing device main body 30 to which the switching mechanism 50 performs the switching operation is set in advance, whereby the developing device main body 30 has the upper limit. The supply roller 43 rotates until the level L is reached, whereby the toner in the toner cartridge 40 is supplied into the developing device main body 30.

  When the toner in the developing device main body 30 reaches the upper limit level L, the switching mechanism 50 operates and the replenishing roller 43 stops, so that the toner supply from the toner cartridge 40 to the developing device main body 30 is not performed. .

  As described above, the switching mechanism 50 is provided for switching the supply roller 43 of the toner cartridge 40 between stop and rotation depending on whether or not the toner amount in the developing device main body 30 has reached the preset upper limit level L. Therefore, it is not necessary to provide a level sensor for detecting the amount of toner stored in the developing device main body 30 as in the prior art, and compared to the case where a portion for retaining the toner in the developing device main body 30 is provided. Thus, supply of toner from the toner cartridge 40 to the developing device main body 30 can be reliably prevented in a state where the toner in the developing device main body 30 reaches the upper limit level L.

  The switching mechanism 50 includes a rotating plate 552 that can rotate around the support shaft 551 in a state where the toner amount in the developing device main body 30 has not reached the upper limit level L, and an integral rotation with the rotating plate 552. Then, the switching lever 553 for changing the posture between the allowable posture S1 for allowing the rotation of the replenishing roller 43 and the regulating posture S2 for restricting the rotation of the replenishing roller 43, and the switching lever 553 are set to the allowable posture S1. In this state, the driving force from the driving motor 21 is transmitted to the replenishing roller 43, while the switching lever 553 is set in the restricting posture S2 to interrupt transmission of the driving force from the driving motor 21 to the replenishing roller 43. Since the clutch 54 is provided, when the toner loaded in the developing device main body 30 has not reached the upper limit level L, the switching lever 553 rotates the replenishing roller 43. Because it is the attitude set the allowable position S1 for permitting toner in the toner cartridge 40 is supplied to the developing device main body 30 by the driving rotation of the supply roller 43.

  As a result, the rotation plate 552 is rotated around the support shaft 551 as the toner amount in the developing device 20 increases, and the switching lever 553 integrated with the rotation plate 552 is rotated at the same time. When the toner in the developing device main body 30 reaches the upper limit level L, the switching lever 553 is changed to the restriction posture S2, whereby the spring clutch 54 transmits the driving force from the driving motor 21 to the supply roller 43. In order to shut off, the toner supply from the toner cartridge 40 into the developing device main body 30 is interrupted. Accordingly, it is possible to prevent the toner from becoming excessive in the developing device main body 30.

  When the toner in the developing device main body 30 is consumed in this state and becomes lower than the upper limit level L, the pressing force of the toner against the rotating plate 552 decreases. When the pressing force is smaller than the biasing force of the torsion spring 554, the switching lever 553 integrated with the rotating plate 552 rotates in the reverse direction around the support shaft 551 and changes the posture from the restricted posture S2 to the allowable posture S1. As a result, the spring clutch 54 transmits the driving force from the driving motor 21 to the replenishing roller 43, so that the toner is supplied from the toner cartridge 40 to the developing device main body 30.

  In this way, the switching lever 553 rotates forward and backward through the rotating plate 552 according to the amount of toner in the developing device main body 30, and the switching lever 553 is thereby moved between the allowable posture S1 and the regulating posture S2. Since the supply roller 43 is driven to rotate or stop by the action of the spring clutch 54 due to the posture change, the level of toner in the conventional developing device main body 30 is detected by a level sensor, and this detection signal is generated. Based on this, the switching mechanism 50 can be simplified as compared with the method of controlling the supply of toner into the developing device main body 30.

  The replenishing roller 43 is provided with a replenishing roller side gear 44 that is concentric with the replenishing roller 43 and can rotate integrally therewith, while the toner cartridge 40 is supplied with the first relay to which the driving force of the driving motor 21 is transmitted. A gear 51 and a second relay gear 52 that are concentrically opposed to the first relay gear 51 and mesh with the replenishing roller side gear 44 and are prevented from rotating by the switching lever 553 that is set in the restriction posture S2. Is provided.

  The spring clutch 54 is interposed between the first and second relay gears 52 and transmits the driving rotation of the first relay gear 51 to the second relay gear 52 by the frictional force generated by the urging force. Since the driving rotation of the first relay gear 51 is not transmitted to the second relay gear 52 in a state where the rotation of the 52 is blocked, the toner in the developing device main body 30 has reached the upper limit level L. In the absence state, since the switching lever 553 is set to the allowable posture S1, the rotation of the second relay gear 52 is not blocked by the switching lever 553, and therefore, the driving rotation of the first relay gear 51 is spring-loaded. The toner is transmitted to the replenishing roller side gear 44 via the clutch and the second relay gear 52, and the toner in the toner cartridge 40 is supplied into the developing device main body 30 by the rotation of the replenishing roller 43 caused thereby. It is.

  On the other hand, when the toner in the developing device main body 30 reaches the upper limit level L, the switching lever 553 changes its posture from the allowable posture S1 to the restricting posture S2, and the rotation of the second relay gear 52 is prevented. Even if the first relay gear 51 is driven to rotate, the spring clutch slips and the second relay gear 52 does not rotate. Accordingly, the replenishment roller side gear 44 meshed with the second relay gear 52 does not rotate, and the toner in the toner cartridge 40 is not supplied into the developing device main body 30.

  As described above, the first relay gear 51 to which the driving force of the drive motor 21 is transmitted is concentrically opposed to the first relay gear 51 and meshes with the supply roller side gear 44 and is set to the restriction posture S2. The replenishing roller side gear 44 in a state in which the toner in the developing device main body 30 has reached the upper limit level L by interposing a spring clutch between the second relay gear 52 whose rotation is prevented by the switching lever 553 that has been made. That is, the structure for preventing the rotation of the replenishing roller 43 can be simplified.

  In this embodiment, since only a one-component toner is used as the developer, the decrease in the toner due to the absence of the carrier leads to the rotation operation of the immediate rotation plate 552, which is high with respect to the toner decrease. Detection accuracy can be obtained.

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

  (1) In the above embodiment, the printer 10 has been described as an example of the image forming apparatus. However, the present invention is not limited to the printer 10 as an image forming apparatus. It may be a device.

  (2) In the above embodiment, the toner cartridge 40 is detachable from the developing device main body 30. However, in the present invention, the toner cartridge 40 is detachable from the developing device main body 30. The developing device main body 30 and the toner cartridge 40 may be integrated into a so-called developing unit.

  (3) Although the screw feeder 42 is provided in the toner cartridge 40 in the above-described embodiment, the present invention is not limited to the provision of the screw feeder 42 in the toner cartridge 40, and in particular, the screw feeder 42. May not be provided.

  (4) In the above embodiment, the first and second relay gears 51 and 52 and the spring clutch 54 are mounted on the roller shaft 431 of the replenishing roller 43. However, in the present invention, the first and second relay gears are provided. 51 and 52 and the spring clutch 54 are not limited to being mounted on the roller shaft 431 of the replenishing roller 43, but a separate dedicated shaft is provided, and the second relay gear 521 and the spring clutch 54 are mounted on this shaft. It may be.

  (5) In the above embodiment, the spring clutch 54 including the spring disc 541 and the plurality of clutch pieces 542 protruding from the peripheral edge of the spring disc 541 is employed as the clutch mechanism. The invention is not limited to the clutch mechanism being such a spring clutch 54, and a normal coil spring may be adopted as the clutch mechanism. That is, by interposing the coil spring between the second relay gear 52 and the latch gear 53 in a compressed state, the same action as that of the spring clutch 54 of the present embodiment can be obtained.

  (6) In the above-described embodiment, the screw feeder 42 provided with the spiral fins 422 is provided in the cartridge side casing 41. However, instead of the screw feeder 42, the tip edge portion is the inside of the cartridge side casing 41. You may provide the scraping member provided with the scraping blade | wing which rotates around an axis | shaft, slidingly contacting a wall surface.

It is explanatory drawing of the side surface sectional view which shows one Embodiment of the printer 10 which concerns on this invention. FIG. 5 is a partially cutaway perspective view showing an embodiment of the developing device, showing a state where the switching mechanism is disassembled. FIG. 3 is an assembled perspective view of the developing device shown in FIG. 2. FIGS. 4A and 4B are cross-sectional views taken along the line II of FIG. 3, in which FIG. 3A illustrates a state where the switching lever is set to an allowable posture, and FIG. 3B illustrates a state where the switching lever is set to a restricted posture. .

Explanation of symbols

10 Printer (image forming device)
DESCRIPTION OF SYMBOLS 11 Apparatus main body 12 Paper storage part 121 Paper cassette 122 Pickup roller 123 Paper feed conveyance path 124 Registration roller pair 13 Image formation part 131 Photosensitive drum (image carrier)
132 Charger 133 Exposure Device 134 Transfer Roller 135 Cleaning Device 14 Fixing Unit 141 Fixing Roller 142 Pressing Roller 143 Paper Discharge Transport Path 15 Paper Discharge Unit 151 Paper Discharge Tray 20 Developing Device 21 Drive Motor (Drive Unit)
211 gear mechanism 22 driving gear 30 developing device main body 31 main body side casing 311 receiving opening 312 toner supply opening 313 side plate 314 rear plate 315 expanding portion 316 bottom plate 316a arc surface 32 first screw feeder 33 second screw feeder 34 developing roller 35 layer Thickness regulating blade 40 Toner cartridge (developer supply container)
41 Cartridge Side Casing 411 Side Wall 42 Screw Feeder 421 Screw Shaft 422 Spiral Fin 43 Supply Roller 431 Roller Shaft 432 Supply Roller Body 433 Leading Opening 44 Supply Roller Side Gear (Roller Side Gear)
45 Cap nut 50 Switching mechanism 51 First relay gear 52 Second relay gear 521 Relay gear 53 Latch gear 531 Latch 54 Spring clutch (clutch mechanism)
541 Spring disc 542 Clutch piece 55 Rotation adjustment member 551 Support shaft 552 Rotation plate 552a Projection edge 553 Switching lever 554 Torsion spring L Upper limit level (predetermined storage amount)
N Nip portion P Paper P1 Paper bundle S1 Permissible posture S2 Restricted posture V Rotating plate movable space

Claims (4)

By supplying a developer from the developing device to the image carrier on which the electrostatic latent image is formed, a developer image along the electrostatic latent image is formed on the image carrier, and the developer image is formed on the transfer material. In the image forming apparatus configured to transfer,
The developing device includes a developing device main body including a developing roller that supplies a developer to the image carrier by rotation around an axis.
A developer replenishing container having a replenishing roller for replenishing the developer to the developing device main body by rotation around an axis;
An image forming system comprising: a switching mechanism that mechanically switches the replenishing roller between stop and rotation depending on whether or not the developer amount in the developing device main body reaches a predetermined storage amount. apparatus. The switching mechanism includes a rotating plate capable of rotating around a support shaft in a state where the developer amount in the developing device main body does not reach the predetermined storage amount;
A switching lever that changes its position between an allowable posture that rotates integrally with the rotating plate and allows rotation of the replenishing roller, and a regulating posture that restricts rotation of the replenishing roller;
While the switching lever is set in an allowable posture, the driving force from a predetermined driving means is transmitted to the replenishing roller, while in the state where the switching lever is set in a regulating posture, the driving force from the driving means is transmitted. The image forming apparatus according to claim 1, further comprising a clutch mechanism that blocks transmission to the supply roller. The replenishing roller is provided with a roller-side gear that is concentrically and integrally rotatable with the replenishing roller, while the developer replenishing container has a first relay gear to which the driving force of the driving means is transmitted, A second relay gear that is concentrically opposed to the first relay gear and meshes with the roller side gear and is prevented from rotating by a switching lever set in the restricting posture;
The clutch mechanism is interposed between the first and second relay gears, and transmits the driving rotation of the first relay gear to the second relay gear by the frictional force generated by the biasing force, while preventing the rotation of the second relay gear. The image forming apparatus according to claim 2, further comprising a spring clutch that prevents the drive rotation of the first relay gear from being transmitted to the second relay gear in the engaged state.   The image forming apparatus according to claim 1, wherein the developer is composed only of a toner that is a colorant.

Images