JP2006064740A - Development apparatus and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a development apparatus that attains in simple and inexpensive constitution in order to reconcile a smaller residual amount of toner by largely vibrating an elastic member and image void due to excessive feed in a full load condition in the constitution without using a toner residual amount detecting function, and to provide a process cartridge and an electrophotographic image forming apparatus. <P>SOLUTION: One thinnest elastic sheet of the most downstream side has length in which it enters the bottom of the development apparatus in a rotation tracking direction by using the two or more sheets having different free length in different thickness in an agitating member. In addition, concerning the sheets except therefor, an agitating diameter is small and does not enter the bottom of the development apparatus. Therefore, when the toner is at a full load initial stage, the thin part of the sheet hardly agitates the toner, the agitating diameter is small, and is agitating force of only a thick part. In addition, the elastic member (exciting Mylar) is provided on the inclined face of a toner storing part, a dowel is provided on the upper end, and the elastic member is arranged so as to be movable. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a developing device and an image forming apparatus that can be used in an electrophotographic image forming apparatus or the like.

  Here, the image forming apparatus forms an image on a recording medium using an electrophotographic image forming system. Examples of the electrophotographic image forming apparatus include an electrophotographic copying machine, an electrophotographic printer (for example, a laser beam printer, an LED printer, etc.), a facsimile machine, a word processor, and the like.

  The process cartridge described above is a cartridge in which a charging unit, a developing unit or a cleaning unit and an electrophotographic photosensitive member are integrally formed, and this cartridge can be attached to and detached from the image forming apparatus main body. At least one of a charging unit, a developing unit, and a cleaning unit and an electrophotographic photosensitive member are integrally formed into a cartridge so as to be detachable from the main body of the electrophotographic image forming apparatus. Further, it means that at least the developing means and the electrophotographic photosensitive member are integrated into a cartridge so that it can be attached to and detached from the main body of the electrophotographic image forming apparatus.

  When an image forming apparatus using electrophotography is used for a long time, it is necessary to replace the photosensitive drum, to supply and replace the developer, and to adjust, clean and replace the other (charger, cleaner container, etc.). However, such maintenance work is practically difficult except for a service person having specialized knowledge.

  Therefore, in the image forming apparatus using the electrophotographic image forming process, the electrophotographic photosensitive member and the process means acting on the electrophotographic photosensitive member are integrated into a cartridge, and the cartridge can be attached to and detached from the image forming apparatus main body. The process cartridge method is adopted. According to this process cartridge system, the maintenance of the apparatus can be performed by the user himself / herself without depending on the service person, so that the operability can be remarkably improved. Therefore, this process cartridge system is currently widely used in image forming apparatuses.

  The conventional technology will be described with reference to FIGS.

  11 shows a laser beam printer equipped with a process cartridge, FIG. 12 shows a process cartridge, and FIG. 13 shows a developing device.

  The configuration and operation of the laser printer are the same as those in the embodiment of the invention, and the description thereof is omitted here.

  The toner is supplied to the developing roller 41 as follows.

  In the toner chamber 45, a stirring member 80 is disposed near the toner supply opening 45a. The bottom surface of the toner chamber 45 forms an inclined surface 90 that is inclined downward toward the stirring member 80. The inclined surface 90 is set to 65 degrees or more, which is an angle (rest angle) at which the toner slides under its own weight when the process cartridge 2 is mounted on the apparatus main body 1. The toner on the inclined surface 90 slides down the inclined surface 90 by its own weight and is supplied to the stirring member 80. The toner in the vicinity of the stirring member 80 is sent toward the toner supply opening 45a as the stirring member 80 rotates.

  Here, in order to minimize the toner remaining in the toner chamber 45, the bottom surface of the toner chamber is a recess 91 in the vicinity of the stirring member 80, and the extended line of the inclined surface 90 is in contact with or intersects with the rotation region of the stirring member 80. The structure which did it is known (for example, refer patent document 1).

  However, when the inclined surface is 65 degrees or more, there is a problem that the capacity of the toner chamber decreases and the number of printable sheets decreases. Therefore, in order to keep the inclined surface at 65 degrees or more and increase the number of printed sheets, it is necessary to increase the outer shape of the toner chamber. Therefore, in order to improve the space efficiency in the image forming apparatus, it is desirable that the inclination angle of the inclined surface is small.

  However, when the inclination angle of the inclined surface is reduced, there arises a problem that the toner remains in the rear portion of the inclined surface where the stirring member does not reach and a predetermined number of printed sheets cannot be obtained.

  For this reason, even when the inclined surface is equal to or less than the angle of repose, a configuration is known in which an elastic member is disposed on the inclined surface, and the elastic member is vibrated by a stirring member to knock off toner on the inclined surface ( For example, see Patent Document 2).

JP 05-035095 A Japanese Patent Laid-Open No. 14-258598

  Even when the inclination angle of the inclined surface is reduced, as described above, an attempt is made to solve the problem by knocking off the toner on the inclined surface by providing the elastic member on the inclined surface and applying vibration to the elastic member by the stirring member. However, as the number of printable sheets increases, the amount of toner in the process cartridge and the capacity of the toner chamber increase, so that the vibration of the elastic member is further increased to drop the toner on the inclined surface, particularly the toner on the inclined surface, and the toner supply opening It has become necessary to send in the direction. In particular, in an environment where the fluidity of the toner is low, such as a high temperature and high humidity environment, the residual toner tends to increase in the upper part of the inclined surface, and it is necessary to generate more vibration in the elastic member.

  In the past, when the residual toner is generated at the time when image fading has occurred due to insufficient toner supply, the user has solved the problem by taking out the process cartridge from the main body of the image forming apparatus and shaking it.

  However, if the amount of residual toner increases, the number of printable sheets increases from the time when the image fading occurs once the user shakes the process cartridge until the next image fading occurs. At this time, in a configuration in which the toner remaining amount detection function is not used, it is difficult for the user to determine when the toner in the process cartridge runs out. For this reason, in order to determine that the toner will run out once when the image fading has occurred, it is necessary to reduce as much as possible the remaining amount of toner at that point, particularly the amount of toner in the toner chamber not involved in development. . However, in order to reduce the remaining amount of toner, it is necessary to vibrate the elastic member greatly by strengthening the stirring member that vibrates the toner. At this time, if the agitating member is too strong, the conveying force for conveying the toner to the developer carrying member becomes strong when the toner is fully loaded in the initial stage of use, and image omission due to excessive toner filling occurs. There is a possibility. For this reason, it is necessary to make the elastic member vibrate greatly so as to reduce the remaining amount of toner and to eliminate the image missing due to excessive feeding when the toner is fully loaded.

  Accordingly, an object of the present invention is to provide a developing device and an image forming apparatus that can be achieved with a simple and inexpensive configuration in order to solve the above-described problems.

  To achieve the above object, the present invention provides a developer carrier for developing an electrostatic latent image formed on an image carrier, and developing the electrostatic latent image by the developer carrier. A developer accommodating portion for accommodating the developer to be used, an agitating member for agitating the developer accommodated in the developer accommodating portion by rotating, and a developing device mounted on the electrophotographic image forming apparatus main body An inclined surface that is inclined downward toward the developer carrier, and the inclined surface is provided along a rotation path of the agitating member on the downstream side in the inclination direction of the inclined surface. And a flexible elastic member attached to the inclined surface movably along the inclined direction of the inclined surface, wherein the elastic member is above the concave portion and the stirring member Protruding in the rotation area of And the stirring member is formed of a plurality of flexible members having different free lengths and different rotation trajectories, and only one rotation trajectory of the stirring members enters the recess. It is characterized by.

  According to another aspect of the present invention, there is provided an image forming apparatus including an image carrier that carries a latent image, the developing device that develops the latent image with a developer, and a transfer unit that transfers the developer to a recording medium. It is characterized by that.

  According to the present invention, the toner can be supplied to the developing member even when the inclination angle of the bottom surface of the toner chamber is equal to or less than the repose angle, and the amount of the remaining developer can be reduced as much as possible. Further, by setting the inclination angle of the bottom surface of the toner chamber to be equal to or less than the repose angle, the developer accommodating portion can be increased, and the toner accommodating amount can be increased. Furthermore, it is possible to suppress the occurrence of image omission due to excessive toner feeding even in the initial stage when the toner is fully loaded.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1>
The image forming apparatus according to the present invention will be described below with reference to FIGS.
(overall structure)
This image forming apparatus is a laser beam printer using an electrophotographic technique in which a process cartridge 2 is detachably attached to the apparatus main body 1. When the process cartridge 2 is mounted on the apparatus main body 1, an exposure device (laser scanner unit) 3 is disposed above the process cartridge 2, and a recording medium (sheet) that is an image forming target is disposed below the process cartridge 2. Material) A sheet tray 4 containing P is disposed. Further, the image forming apparatus main body 1 includes a pickup roller 5, a paper feed roller (not shown), a transfer roller (not shown), a transfer guide 6, a transfer charging roller 7, along the conveyance direction of the sheet material P. A conveyance guide 8, a fixing device 9, a pair of paper discharge rollers 10, a paper discharge tray 11, and the like are arranged.
(Process cartridge configuration)
The process cartridge 2 integrally accommodates four types of process devices including an image carrier (photosensitive drum) 20, a charging device 30, a developing device 40, and a cleaning device 50. The photosensitive drum 20 and the charging device 30 are attached to a frame 51 of the cleaning device 50. On the other hand, the developing device 40 has coupling arms 48 in the vicinity of both ends thereof.

  The developing device 40 is rotatably attached to the frame 51 by means (not shown) at the tip end region of the coupling arm 48. Further, an urging means 60 that is a coil spring is disposed between the developing device 40 and the frame 51, and the developing device 40 is urged clockwise in the drawing.

Here, an interval holding member (not shown) is attached to both ends of the developing roller 41, and the developing roller 41 is held at a predetermined interval from the photosensitive drum 20.
(Description of image forming process)
Next, an outline of image formation will be described.

  Based on the print start signal, the photosensitive drum 20 is rotationally driven at a predetermined peripheral speed (process speed) in the arrow R1 direction. A charging device 30 to which a bias voltage is applied is in contact with the outer peripheral surface of the photosensitive drum 20, and the outer peripheral surface of the photosensitive drum 20 is uniformly and uniformly charged by the charging device 30.

  The laser scanner unit 3 outputs laser light L modulated in accordance with the time-series electric digital pixel signal of the target image information, and enters the process cartridge 2 from the exposure window 53 on the upper surface of the process cartridge 2. Then, the outer peripheral surface of the photosensitive drum 20 is scanned and exposed. As a result, an electrostatic latent image corresponding to the target image information is formed on the outer peripheral surface of the photosensitive drum 20. This electrostatic latent image is produced by the developer (toner) T on the developer carrying member (developing roller) 41 that has been subjected to tribo application and layer thickness regulation by the developer regulating member (developing blade) 42 of the developing device 40. Developed as an image.

  On the other hand, the sheet material P is fed from the sheet tray 4 by the pickup roller 5, the paper feed roller (not shown), and the conveying roller pair (not shown) in synchronization with the output timing of the laser beam L, and the transfer guide 6 is moved. Then, timing is supplied to the transfer position between the photosensitive drum 20 and the transfer charging roller 7. At this transfer position, the toner image is sequentially transferred from the photosensitive drum 20 to the sheet material P.

  The sheet material P to which the toner image has been transferred is separated from the photosensitive drum 20 and conveyed along the conveyance guide 8 to the fixing device 9, and at the nip portion between the fixing roller 9 a and the pressure roller 9 b constituting the fixing device 9. The toner image is fixed to the sheet material P by pressure and heat fixing processing. The sheet material P that has undergone the toner image fixing process is conveyed to the paper discharge roller pair 10 and discharged onto the paper discharge tray 11.

On the other hand, after the transfer, the remaining toner on the outer peripheral surface of the photosensitive drum 20 is removed by the cleaning blade 52 of the cleaning device 50, and the photosensitive drum 20 is again subjected to image formation starting from charging.
(Configuration of developing device)
The toner T in the toner chamber 45 is conveyed to the developer supply chamber 44 through the toner supply opening 45a by a toner feeding mechanism described later. The toner T conveyed to the developer supply chamber 44 is attracted to the developing roller 41 by the magnet 41a included in the developing roller 41, and conveyed toward the developing blade 42 as the developing roller 41 rotates in the R2 direction. The developing blade 42 is fed in the direction of the photosensitive drum 20 by applying tribo and layer thickness regulation.

  Here, a predetermined developing bias in which an AC voltage is superimposed on a DC voltage is applied to the developing roller 41, and the photosensitive drum 20 is grounded. Since an electric field is generated in a region where the photosensitive drum 20 and the developing roller 41 face each other, the latent image on the surface of the photosensitive drum 20 is developed by the charged toner T described above.

  The present invention provides a developer in which an electrostatic latent image formed on an outer peripheral surface of a photoreceptor in accordance with target image information is subjected to tribo application and layer thickness regulation by a developer regulating member (developing blade) of a developing device. The present invention relates to toner conveyance until a toner is sent from a toner storage portion onto a developing roller in a series of image forming processes until a toner image is developed with a developer (toner) on a carrier (developing roller).

Subsequently, the toner conveying means according to the present invention will be described in detail.
(Description of toner conveying means)
The stirring member 43 is disposed in the vicinity of the toner supply opening 45a of the toner chamber 45, and is rotationally driven in the direction of arrow R3 by a driving unit (not shown). The stirrer 43 has a rigid rod 43b attached to a mounting shaft 43a rotatably supported by a frame constituting the toner chamber 45, and a stirrer sheet 43c made of polyethylene terephthalate having a thickness of 188 μm, further downstream in the rotational direction. On the side, a stirring sheet 43d made of polyphenyl sulfide and having a thickness of 50 μm is provided. In addition, the length 53a of the stirring sheet 43c is arranged to protrude from the rigid rod by 3.0 mm, and the length 53b of the stirring sheet 43d is 6.0 mm. The bottom surface of the toner chamber in the immediate vicinity of the stirring member 43 forms a recess 45e along the rotation radius of the stirring member 43.

  Further, the stirring sheet 43d of the stirring member was disposed in the recess 45e at the bottom of the developer storage portion with an intrusion amount of 2.0 mm. Here, the amount of the stir sheet entering the recess 45e needs to take into account that the stirrer 43 reliably vibrates the elastic member 47, and considers torque and noise during toner agitation. It is desirable to set to about 0 mm, preferably about 2.0 to 3.0 mm. Further, an edge 45f is formed between the inclined surface 45b descending toward the recess 45e and the recess 45e.

  The stirring member 43 is made of a polyethylene terephthalate material and an elastic member 47 having a thickness of 70 μm on an inclined surface 45b inclined downward in the direction toward the developing roller 41 and the agitating member 43 on the bottom surface of the toner chamber 45. Projecting so as to have a projecting amount of 4.0 mm. Here, the protruding amount is a distance 47b from the tip of the elastic member 47 to the edge 45f.

  The elastic member 47 has an elongated fitting hole 47a corresponding to the dowel 45c located on the inclined upstream side of the inclined surface 45b as shown in FIG. 4, and the hole 47a is fitted in the dowel 45c. The dowel 45c is fixed on the inclined surface 45b, and the tip of the dowel 45c is expanded and fixed by heat welding or the like. Note that the backlash along the inclination direction of the fitting hole 47a and the dowel 45c is set to 2 mm in this embodiment. Here, the distance from the tip side neck under the dowel 45c melted by heat welding or the like to the root of the dowel 45c is equal to or greater than the thickness of the elastic member 47, and in this embodiment, it is set to have a backlash of 2 mm. .

  Further, the fitting hole 47a is set to have a backlash with respect to the dowel 45c in the width direction so that the elastic member 47 can be displaced in all directions, in this embodiment, a backlash of 1 mm. The dowels 45c may be provided at one place when the elastic member 47 is provided over the entire length of the toner chamber 45 in the longitudinal direction, and usually provided at two or more places. There are three dowels 45c in this example.

  The elastic member 47 is disposed over substantially the entire area in the direction of inclination of the inclined surface 45b and in the direction intersecting the inclination direction, and the movable part on the opposite side of the fixed part fixed by the above-described thermal welding or the like. The tip is disposed as indicated by reference numeral 47b in FIG. 3 so as to protrude above a recess 45e provided along the rotation path of the stirring member 43 located on the downstream side of the inclined surface 45b in the inclination direction. Here, the downstream side in the inclination direction is related to the moving direction of the toner, and is the lower side of the inclined surface 45b.

  Here, it is necessary to consider that the protruding amount of the protruding portion 47b surely vibrates when the elastic member 47 comes into contact with the stirring member 43 and that the vibration does not affect the image and noise. About 0.0 mm, preferably about 2.0 mm to 5.0 mm is desirable.

  The length (length from the center of the dowel 45c to the tip of the elastic member on the downstream side of the inclined surface) 54 along the inclined surface direction of the elastic member was set to 60 mm.

  As described above, the elastic member 47 has the movable portion tip positioned above the concave portion 45e provided along the rotation path of the stirring member 43 located on the downstream side in the tilt direction of the inclined surface 45b and the rotation region of the stirring member 43. Therefore, when the stirring member 43 is rotated in the R3 direction, it bends toward the concave portion when contacting the stirring member, and returns by elastic force when spaced apart. To vibrate the toner T. This operation of applying vibration continues while the process cartridge 2 operates and the stirring member 43 rotates.

  Further, since the elastic member 47 is fixed with a certain amount of looseness by fitting the elongated hole 47a to the dowel 45c as described above, the elastic member 47 intersects the inclination direction and the inclination direction of the elastic member 47. It vibrates over almost the whole area in both directions. Then, the toner T to which vibration is applied falls on the upper surface of the elastic member 47 disposed on the inclined surface 45b over substantially the entire area, and the dropped toner T is positioned downstream of the inclined surface 45b in the inclination direction. It reaches the recess 45e and the stirring member 43 provided along the rotation path of the stirring member 43, and the toner is sent to the toner supply opening 45a as the stirring member 43 rotates.

  As described above, even when the inclination angle of the inclined surface of the toner chamber is equal to or less than the angle of repose (20 degrees to less than 65 degrees), the elastic member is fixed to a certain degree of backlash by heat welding or the like on the inclined surface. In addition, by providing a protrusion in the rotation region of the stirring member 43, stable toner dropping and toner supply can be achieved with vibrations over substantially the entire area of the elastic member 47 caused by the rotation of the stirring member 43. It becomes possible.

The vibration motion of the elastic member in the present embodiment will be described in detail in chronological order using (1) to (6) of FIG.
(1) First, the stirring member 43 starts to rotate in the direction of R3.
(2) When the stirring member 43 rotates and comes into contact with the elastic member 47, the tip of the stirring member comes into contact with the inclined surface above the edge 45f because the tip has entered the recess 45e. A frictional force is generated by the contact between the stirring sheet portion of the stirring member 43 and the elastic member 47, and the elastic member 43 is forced toward the lower portion of the inclined surface so as to follow the stirring member 47 (F1).
) Is added. At this time, since the dowels 45c are arranged on the upper part of the elastic member so as to be loose in the direction of the inclined surface, the elastic member moves so as to be pulled by the stirring member 43 below the inclined surface. Therefore, the toner pile loaded on the upper part of the elastic member moves in the direction of the lower part of the inclined surface so as to collapse due to the movement of the elastic member toward the lower part of the inclined surface.
(3) When the tip of the stirring member 43 passes through the edge 45f and enters the recess 45e, the stirring member 45 tends to rotate along the recess, so that the elastic member 47 is bent downward along the recess. A force (F ₂ ) is applied to the elastic member. The downward force at this time is broken down into components in the direction of the inclined surface and the direction perpendicular to the inclined surface (3), and arrows (F _2a , F _2b ) in the figure. The elastic member is further pulled toward the lower portion of the inclined surface by the force F _{2a of the} component along the inclined surface of the downward force. Further, the elastic member 47 bends along the concave portion with the edge 45f as a fulcrum by the force F _2b of the component perpendicular to the inclined surface.
(4) When the stirring member 43 further rotates and the tip enters the recess 45e, the elastic member 47 protrudes with respect to the recess. Therefore, the elastic member 47 is elastically deformed with the edge 45f as a fulcrum, and from the inclined surface. Bends like floating. At this time, naturally, since the stirring member 43 is made of a flexible material, it bends at the same time. When the stirring member bends, the amount of time the elastic member bends can be increased by extending the time for the elastic member and the stirring member to contact each other. Further because it has a sheet length penetrated into the concave portion of the agitating member, thereby applying a force (F ₃₎ in the direction perpendicular to the recess. At this time, the force of the component along the direction of the inclined surface and the force of the direction component perpendicular to the inclined surface are indicated by arrows in (4) (F _3a , F _3b ).
(5) The elastic member 47 is elastically deformed by the force (F ₂ , F ₃ ) generated when both the stirring member 43 and the elastic member 47 are bent, and a relaxation action is exerted when the elastic energy is held. Therefore, the elastic member 47 tries to return from the deformed state. At this time, since the dowel 45c is provided at the upper portion of the elastic member 47 in the inclined surface direction, the elastic member 47 moved below the inclined surface moves along the inclined surface direction of the elastic energy. It moves to the upper part of the inclined surface by the force (F ₄ ) of the component. Furthermore, since the dowels 45c are arranged so as to generate backlash in a direction perpendicular to the inclined surface, the upward vibration is simultaneously generated in the dowels 45c by the force (F ₅ ) of the component perpendicular to the inclined surface of the elastic energy. Arise. That is, the movement in the upper direction of the inclined surface in the vicinity of the dowel 45c and the direction perpendicular to the inclined surface through the retention of elastic energy by the deformation of the elastic member by the force generated by the contact and bending of both the stirring member and the elastic member The movement will occur. Therefore, the toner can be vibrated at the upper portion of the inclined surface by vibration in the inclined surface direction and vibration in a direction perpendicular to the inclined surface.
(6) At the moment when the stirring member leaves the elastic member 47 in the recess 45e, the elastic member 47 begins to oscillate perpendicular to the inclined surface because the material bent by the edge 45f tries to return to the original state ((5) In the drawing, the toner a deposited on the elastic member is blown off, and the dropped toner reaches the recess 45e and the stirring member 43, and the toner is sent toward the toner supply opening 45a as the stirring member 43 rotates.
(7) The series of vibration motions (1) to (6) is repeated while the stirring member 43 continues to rotate.

  As described above, it is possible to reduce the residual toner on the elastic member 47, in particular, on the inclined surface of the elastic member, by a series of vibration movements of the elastic member.

  Although the explanation regarding the above motion can be achieved only when the stirring member is an elastic sheet, according to the configuration of the present invention, it is possible to further reduce the residual toner. The superiority in the present invention will be described below.

According to this embodiment, two flexible elastic sheets are stacked on the stirring member, and the thickness of the stirring sheet disposed on the most downstream side and the stirring sheet disposed on the upstream side thereof are different. That is, the strength against elastic deformation differs between the two stirring sheets. Therefore, as shown in FIG. 7A, when the most downstream stirring sheet comes into contact with the elastic member and vibrates the elastic member, and at the same time pulls the inclined surface downstream, the free end of the upstream stirring sheet It becomes possible to apply a strong vertical force (F ₂ ) with (a) as a fulcrum. Here, in order to increase the force (F ₂ ) in the vertical direction, for example, a method of increasing the thickness of one stirring sheet is conceivable. However, since the thick stirring sheet penetrates into the concave portion at the bottom of the developing device, development is performed. The rubbing noise with the bottom of the vessel will increase.

  However, in the present embodiment, the thick stirring sheet does not enter the recess at the bottom of the developing device, and the rubbing noise can be reduced. After that, as shown in FIG. 7B, when the stirring member rotates and a force for pulling the elastic member to the downstream side of the inclined surface is generated, this time, the most downstream stirring sheet attached to the stirring member. Force enters in the upstream direction of the rotation trajectory. Therefore, since the upstream stirring sheet is a flexible elastic sheet, it is elastically deformed with the end portion (b) of the rigid body as a fulcrum. At this time, since the upstream agitating sheet undergoes elastic deformation, the time for which the agitating sheet and the elastic member are in contact with each other becomes longer, so that the elastic motion in the direction of the inclined surface of the elastic member is increased. By using this configuration, the vibration motion perpendicular to the inclined surface of the elastic member and the elastic motion parallel to the inclined surface can be increased, and the residual toner on the upper portion of the inclined surface can be further dropped.

  Next, the movement of the stirring member and the movement of the elastic member when the toner amount is actually full will be described. When the toner amount is full, the stirring sheet 43d of the stirring member is greatly bent due to the weight of the toner, and the ability to stir and transport the toner is hardly obtained (FIG. 8A). The agitating sheet 43c and the rigid rod 43a disposed on the upstream side in the rotation direction are responsible for the action of actually agitating and conveying the toner. In addition, since 43c is made of a flexible material, the agitation / conveyance capacity is reduced by bending to some extent with the rigid rod 43a as a fulcrum. Deflection of 43c to some extent can suppress image omission due to excessive toner feeding in the initial stage when toner is fully loaded. In addition, since the force that vibrates the elastic member is naturally reduced, the toner at the upper portion of the inclined surface is not sent in the direction of the developer carrying member, and the toner is not fed more than necessary. For this reason, if the stirring member is made a rigid body and the elastic member is vibrated by the rigid body, naturally the feeding of the toner becomes stronger, which may cause the above problem.

  On the contrary, when the toner is consumed to some extent and the remaining amount of toner is reduced, the toner remains on the inclined surface. As shown in FIG. 8B, the portion where the vibration in the direction perpendicular to the inclined surface with the largest vibration starts the toner dropping first, and when the toner further decreases, the portion shown in FIG. Thus, residual toner is generated on the upper part of the inclined surface of the elastic member 47. By reducing the amount of toner, the vibration motion of the elastic member can be increased. At this time, the toner remaining on the inclined surface of the elastic member 47 by the vibration motion perpendicular to the inclined surface along the inclined surface direction. Thus, the toner can be dropped from the elastic member 47. Further, the stirring sheet 43b does not bend greatly because the weight of the toner is small, and the elastic member can be vibrated efficiently and the toner can be conveyed in the direction of the developer carrying member.

  For the above reasons, the present invention using an elastic sheet having different thicknesses with different thicknesses for the stirring member is superior to using only one elastic sheet or a stirring member made of only one rigid body. It can be said. Therefore, next, it will be examined how the remaining amount of toner can be reduced most if the relationship between the free lengths of the two elastic sheets in the configuration described in this embodiment.

  Therefore, it is verified whether or not image omission due to excessive toner feeding in the initial stage when the toner is fully loaded, and on the elastic member 47 at the time when image fading occurs due to insufficient toner supply when the remaining amount of toner decreases. Table 1 shows the results of the remaining amount of toner and the relative evaluation of noise such as rubbing noise when there is no toner. The conditions were a high temperature and high humidity environment with a temperature of 32.5 ° C and a humidity of 80%.

  As a configuration in the present embodiment, the thickness of the stirring member 43c is 50 μm, the amount of penetration into the recess is 2.0 mm, the stirring sheet length is 6.0 mm, the amount of sheet protrusion of the stirring member 43b is 3.0 mm, the sheet thickness is 188 μm, and elasticity The sheet thickness of the member was 70 μm, the protrusion amount was 4.0 mm, the elastic member length was 60 mm, and the angle formed with the bottom when the inclined surface was put in the image forming apparatus main body was 40 °.

  As a comparison object, the length of the stirring sheet 43b attached upstream with respect to the rotation direction is changed. (A) Free length 53b = 9.0 mm (the same length as the stirring sheet 43c), (b) A comparative study was conducted with a free length 53b = 5 mm (2.0 mm of the elastic member entered the rotation locus) and (c) free length = 0 mm (only one 50 μm stirring sheet).

  Regarding the initial image omission, 30 halftones are continuously passed in each configuration, and a relative evaluation is made as to how much image omission has occurred on the image. At this time, the case where no image omission occurred was evaluated as ◯, the case where image omission occurred slightly was evaluated as Δ, and the case where many image omissions occurred was evaluated as x. Also, when the image is blurred due to insufficient toner supply due to low toner remaining, ○ when there is almost no toner remaining on the elastic member, △ when some toner remains, and when a large amount of toner remains X was evaluated by relative comparison.

表１に示した結果に関して詳細に説明する。

The results shown in Table 1 will be described in detail.

  First, in (a), the 188 μm stirrer sheet is the same length as the 50 μm stirrer sheet, and the toner is strongly fed in the initial stage when the toner is fully loaded. Further, regarding the remaining amount of toner, the force in the direction perpendicular to the inclined surface is strong, but the elastic member does not move so that the elastic member returns to the upper portion of the inclined surface, and the toner remains on the upper portion of the inclined surface. Further, since the stirring sheet penetrates into the recess at the bottom of the developing device, the rubbing noise was very loud when there was no toner. Next, regarding (b), the initial image omission was good.

  However, the remaining amount of toner was almost the same as (a). This is because the tip of the elastic member has entered the rotation trajectory of the stirring sheet of 188 μm, so that the stirring sheet of 188 μm before the 50 μm stirring sheet passes through the edge 45f and enters the recess to bend the elastic member. However, there was a phenomenon that the elastic member was bent first. Therefore, it is considered that the vibration motion of the elastic member by the stirring sheet, particularly the vibration motion along the inclined surface has been reduced. As for noise, the sound when the 188 μm stirring sheet was in contact with the elastic member was loud, and the noise level was good compared to (a). Regarding (c), the initial image omission was good. However, with respect to the remaining amount of toner, the vibration in the direction perpendicular to the inclined surface of the elastic member is small and the toner remains on the upper portion of the inclined surface.

  From the above results, it is desirable that the stirrer sheet attached to the upstream side with respect to the rotation direction attached to the stirrer member in this embodiment is about 1 to 3 mm, and the elastic member does not enter the rotation trajectory. .

  In this embodiment, the material of the elastic member is polyethylene terephthalate, and the stirring sheet member of the stirring member is polyphenylene sulfide and polyethylene terephthalate. However, any of polyacetal, polyphenylene sulfide, and polyethylene terephthalate may be used.

  In this embodiment, an elastic member having a thickness of 70 μm is used. However, from the viewpoint of vibration noise and rubbing noise between the stirring member, the elastic member may be set to about 50 μm to 200 μm, preferably about 50 μm to 100 μm. desirable.

  Regarding the thickness of the stirring member, a 50 μm stirring sheet was used on the most downstream side in the present embodiment, but about 20 μm to 150 μm, preferably from the viewpoint of imparting vibration to the elastic member and noise that rubs against the torque during stirring. Is preferably set to about 20 μm to 100 μm. Further, although 188 μm is used for the upstream agitating sheet, it is desirably 150 μm to 300 μm, preferably 150 to 250 μm from the viewpoint of imparting vibration and stirring power of the toner.

  As described above, according to the embodiment of the present invention, the flexible stirring member is inserted into the concave portion provided along the rotation locus of the stirring member, and the elastic member is placed on the inclined surface of the toner chamber. Protruding into the rotation area and disposed above the recess, the inclination of the elastic member is generated in conjunction with the rotation of the stirring member even if the inclination angle of the inclined surface is less than the repose angle (20 degrees to less than 65 degrees). In addition to vibration in a direction perpendicular to the surface, both the stirring member and the elastic member bend to cause movement of the elastic member in the direction along the inclined surface, so that toner can be more stably dropped and supplied. The amount of toner remaining in the room can be reduced to a small amount, and image omission due to excessive toner feeding can be suppressed even in the initial stage when the toner is fully loaded.

  In addition, it is possible to improve the space efficiency in the image forming apparatus with a simple and inexpensive configuration.

<Embodiment 2>
In the second embodiment, in addition to the configuration of the first embodiment, the angle at which the stirring sheet portion of the stirring member bends is regulated. Hereinafter, the configuration of the present embodiment will be described with reference to FIG. At this time, in order to prevent the back-up portion from being bent by the force applied to the stirring sheet, several ribs 62 are provided in the longitudinal direction of the stirring rod so that the back-up portion is not bent beyond a certain limit. In the present embodiment, three ribs are arranged at equal intervals in the longitudinal direction. For this reason, when the stirring sheet comes into contact with the elastic member and a force is applied in the direction opposite to the rotation direction, the stirring sheet is elastically deformed in order from the downstream stirring sheet with respect to the thin rotation direction, and the stirring sheet is bent. become. The angle at which the backup is bent at this time is preferably about 5 to 20 ° with respect to the stirring radial direction from the force that gives vibration to the elastic member, the sound during stirring, and the like.

  In this embodiment, 10 ° is used. For this reason, the stirring sheet attached to the downstream side with respect to the rotation direction of the stirring member can be made somewhat thin, and image omission due to excessive feeding when the toner is fully loaded can be further suppressed. Further, when the stirring sheet comes into contact with the elastic member by thinning the stirring sheet on the downstream side and facilitating the bending of the stirring sheet, in Embodiment 1, the stirring sheet is elastically deformed in order from the stirring sheet on the most downstream side. The tip contacts the elastic member (FIG. 10A).

  However, in the second embodiment, when the stirring sheet comes into contact with the elastic member, the entire stirring sheet undergoes elastic deformation and the contact area becomes larger (FIG. 10B). Therefore, it takes a long time for the elastic member attached to the inclined surface and the stirring sheet to come into contact with each other, and the elastic member is vibrated accordingly, and the remaining toner on the upper portion of the inclined surface can be removed. The movement of the elastic member at this time is equivalent to that described in the first embodiment.

  As described above, by using the configuration of the present embodiment, it is possible to give more vibration to the elastic member.

It is a longitudinal cross-sectional view of a developing device. 1 is a longitudinal sectional view of an image forming apparatus. It is a longitudinal cross-sectional view of a process cartridge. It is a fragmentary sectional view of a developing device. It is the schematic regarding the length of a stirring member and an elastic member. It is a schematic diagram of the vibration motion of an elastic member. It is the schematic of the elastic deformation of a stirring member. FIG. 3 is a schematic diagram of a toner remaining state. It is the schematic of the stirring member which concerns on Embodiment 2 of this invention. It is the schematic at the time of the contact of the stirring member and elastic member which concern on Embodiment 2 of this invention. It is a longitudinal cross-sectional view of a conventional image forming apparatus. It is a longitudinal cross-sectional view of the conventional process cartridge. It is a longitudinal cross-sectional view of a conventional developing device.

Explanation of symbols

1. Image forming device body (device body)
2 Process cartridge 3 Exposure device (laser scanner unit)
4 Sheet tray 5a Pickup roller 5b Feed roller 5c Conveying roller pair 6 Transfer guide 7 Transfer charging roller 8 Conveying guide 9 Fixing device 10 Paper discharge roller 11 Paper output tray 20 Photosensitive drum 30 Charging device 40 Developing device 41 Developer carrier (Development roller)
42 Developer regulating member (developing blade)
43 stirring member 43a mounting shaft 43b stirring sheet 44 developer supply chamber 45 toner chamber 45a toner supply opening 45b inclined surface 45c dowel 45e concave portion 47 elastic member 47a hole 47b rigid body 47c elastic sheet 1
47d Elastic sheet 2
48 coupling arm 50 cleaning device 51 frame 52 cleaning blade 53 stirring sheet length 54 elastic member length 60 coil spring 61 rib L laser light P recording medium (sheet material)
T Developer (toner)

Claims (9)

A developer carrier for developing the electrostatic latent image formed on the image carrier, and a developer for storing the developer used for developing the electrostatic latent image by the developer carrier An agitating member that agitates the developer accommodated in the developer accommodating portion by rotating; and the developer that becomes a bottom surface when the developing device is attached to the electrophotographic image forming apparatus main body. An inclined surface inclined downward toward the carrier, and on the downstream side of the inclined direction of the inclined surface, the inclined surface is a recess provided along a rotation path of the stirring member, and an inclined direction of the inclined surface And a flexible elastic member attached to the inclined surface movably along the developing device,
The elastic member is provided above the recess and protruding in the rotation region of the stirring member, and the stirring member is formed of a plurality of flexible members having different free lengths and different rotation trajectories, The developing device according to claim 1, wherein only one rotation locus of the agitating member enters the recess.   The stirring member has a rigid body integral with a rotating shaft, a base end portion is fixed to the rigid body, and a distal end portion is an elastic sheet having a free end, and the elastic sheet includes two or more sheet materials. The sheet material on the upstream side in the rotation direction of the stirring member is shorter in the radial direction than the sheet material on the downstream side, and the elastic sheet on the most upstream side penetrates into the recess. The developing device according to claim 1, wherein:   The elastic member has an elongated hole along the inclined direction of the inclined surface, and the inclined surface is provided with a dowel, and the elastic member is formed by fitting the hole into the dowel. The developing device according to claim 1, wherein the elastic member is attached to the inclined surface so as to be movable along an inclination direction of the inclined surface.   The developing device according to claim 1, wherein an amount of the developer stirring member entering the concave portion is 1.0 mm or greater and 4.0 mm or less.   5. The developing device according to claim 1, wherein a thickness of the most downstream sheet in the rotation direction of the developer agitating member is 20 μm or more and 100 μm or less.   The developing device according to claim 1, wherein an amount of protrusion of the elastic member into the concave portion is 1.0 mm or greater and 6.0 mm or less.   The developing device according to claim 1, wherein the elastic member is made of a flexible resin and has a thickness of 50 μm to 200 μm.   8. The developing device according to claim 1, wherein the developing device is a process cartridge that can be attached to and detached from the electrophotographic image forming apparatus main body.   An image carrier that carries a latent image, a developing device according to claim 1 that develops the latent image with a developer, and a transfer unit that transfers the developer to a recording medium. An image forming apparatus.

Images