JP6635068B2 - Developing device and image forming apparatus provided with the same - Google Patents

Description

  The present invention relates to a developing device for supplying a developer to an image carrier and an electrophotographic image forming apparatus including the same.

  An electrophotographic image forming apparatus irradiates light based on image information read from a document image or image information transmitted from an external device such as a computer onto the peripheral surface of an image carrier (photosensitive drum). After forming an electrostatic latent image and supplying toner from the developing device to the electrostatic latent image to form a toner image, the toner image is transferred to paper. The sheet after the transfer process is discharged to the outside after the toner image is fixed.

  In recent years, in an image forming apparatus, the configuration of the apparatus has become complicated with the progress of color printing and high-speed processing, and a high-speed rotation of a toner stirring member in a developing apparatus has been inevitable in order to cope with high-speed processing. . In particular, in a developing method using a two-component developer containing a magnetic carrier and a toner, and using a magnetic roller (toner supply roller) carrying the developer and a developing roller carrying only the toner, the developing roller, the magnetic roller, In the opposing portion, only the toner is carried on the developing roller by the magnetic brush formed on the magnetic roller, and the toner not used for development is peeled off from the developing roller. As a result, toner is liable to be scattered in the vicinity of a portion where the developing roller and the magnetic roller are opposed to each other, and the toner floating in the developing device accumulates around the cutting blade (regulating blade), and the accumulated toner is aggregated. If the toner adheres to the developing roller, the toner may be dropped and an image defect may occur.

  Therefore, for example, Patent Documents 1 and 2 disclose a developing device using a two-component developer containing a magnetic carrier and a toner, and a developing device using a magnetic roller carrying the developer and a developing roller carrying only the toner. Alternatively, a toner receiving support member facing the magnetic roller, a toner receiving member arranged along the longitudinal direction of the toner receiving support member for receiving toner dropped from the developing roller, and vibration generating means for vibrating the toner receiving member are provided. A developing device is disclosed.

JP 2012-208469 A JP 2014-6411 A

  When a plate-shaped toner receiving member having both free ends is vibrated as in Patent Literatures 1 and 2, the mounting position of the vibration motor having a large inertial weight becomes a node of amplitude and does not vibrate. Further, the end of the toner receiving member vibrates largely as an antinode of the amplitude. In other words, the toner accumulated at the end is easily dropped by the vibration, but the toner accumulated at the center cannot be dropped.

  Further, a coil spring attached to make the vibration direction of the toner receiving member substantially vertical has an action of generally restricting the vibration motion, and reduces the amplitude. When the natural frequency of the coil spring is the same as the natural frequency of the toner receiving member, the amplitude increases because the coil spring and the toner receiving member resonate at the same frequency. However, the amplitude of the portion to which the coil spring is attached excessively increases, resulting in an uneven amplitude distribution in the longitudinal direction of the toner receiving member, which is not desirable.

  In view of the above problems, the present invention suppresses excessive vibration of a toner receiving member, thereby suppressing the scattering of toner accumulated on the toner receiving member and efficiently collecting the toner, and an image provided with the developing device. It is an object to provide a forming device.

  In order to achieve the above object, a first configuration of the present invention includes a developing roller, a toner supply roller, a regulating blade, a casing, a toner receiving support member, a toner receiving member, and a vibration generating device. Developing device. The developing roller is disposed to face the image carrier on which the electrostatic latent image is formed, and supplies the toner to the image carrier in a region facing the image carrier. The toner supply roller is arranged to face the developing roller, and supplies toner to the developing roller in a region facing the developing roller. The regulating blade is opposed to the toner supply roller at a predetermined interval. The casing contains a developing roller, a toner supply roller, and a regulating blade. The toner receiving and supporting member is disposed in the casing, and faces the developing roller or the toner supply roller between the regulating blade and the image carrier. The toner receiving member has a toner receiving surface that is disposed along the longitudinal direction of the toner receiving support member and that receives the toner dropped from the developing roller. The vibration generator vibrates the toner receiving member. Weights are provided on the back side of the toner receiving surface at one or more positions where the amplitude in the longitudinal direction becomes maximum when the toner receiving member is vibrated.

  According to the first configuration of the present invention, by attaching the weight to a position where the amplitude becomes maximum when the toner receiving member is vibrated, the amplitude at a portion where the amplitude is too large can be suppressed. As a result, it is possible to effectively suppress the toner scattering to the outside of the developing device due to the scattering of the toner accumulated in a portion where the amplitude is too large, and to efficiently collect the toner accumulated in the toner receiving member. it can.

Schematic configuration diagram of a color printer 100 equipped with the developing devices 3a to 3d of the present invention Side sectional view of developing device 3a according to one embodiment of the present invention mounted on color printer 100 FIG. 4 is a perspective view of the toner receiving and supporting member 35 used in the developing device 3 a according to the present embodiment as viewed from the inside of the developing container 20. Exploded perspective view of a toner receiving and supporting member 35 used in the developing device 3a of the present embodiment. Exploded perspective view of the vibration generator 42 Front view of vibration motor 43 Side view of the vibration motor 43 viewed from the vibration weight 50 side FIG. 4 is a side cross-sectional view around the toner receiving support member 35 in the developing device 3 a of the present embodiment, showing a cross section near the vibration motor 43. FIG. 4 is a side cross-sectional view of the vicinity of a toner receiving support member 35 in the developing device 3a of the present embodiment, showing a cross section including a coil spring 40; 4 is a graph showing the distribution of the amplitude of the toner receiving member 37 when the vibration motor 43 is rotated at 80.9 Hz (4844 rpm). 4 is a graph showing the distribution of the amplitude of the toner receiving member 37 when the vibration motor 43 is rotated at 116.8 Hz (6944 rpm). 7 is a graph showing the distribution of the amplitude of the toner receiving member 37 when the vibration motor 43 is rotated at 135.2 Hz (8084 rpm). 7 is a graph showing the distribution of the amplitude of the toner receiving member 37 when the vibration motor 43 is rotated at 138.8 Hz (8311 rpm). 4 is a graph showing the distribution of the amplitude of the toner receiving member 37 when the vibration motor 43 is rotated at 195.1 Hz (11682 rpm). On the back side of the toner receiving surface 37b, a 1 g weight 60 is attached at a position of -150 mm and 150 mm from the center in the longitudinal direction, and the longitudinal direction of the toner receiving member 37 when the vibration motor 43 is rotated at 108 Hz (6480 rpm). Graph showing the distribution of amplitude in

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic sectional view of an image forming apparatus on which the developing devices 3a to 3d of the present invention are mounted. Here, a tandem type color printer is shown. In the main body of the color printer 100, four image forming units Pa, Pb, Pc and Pd are arranged in order from the upstream side in the transport direction (the right side in FIG. 1). These image forming portions Pa to Pd are provided corresponding to images of four different colors (cyan, magenta, yellow, and black), and are formed by charging, exposing, developing, and transferring, respectively, cyan, magenta, and yellow. And black images are sequentially formed.

  Photosensitive drums 1a, 1b, 1c and 1d each carrying a visible image (toner image) of each color are arranged in these image forming portions Pa to Pd, respectively, and further rotate clockwise in FIG. An intermediate transfer belt 8 is provided adjacent to each of the image forming units Pa to Pd.

  When image data is input from a host device such as a personal computer, first, the chargers 2a to 2d uniformly charge the surfaces of the photosensitive drums 1a to 1d. Next, the exposure device 5 irradiates light according to the image data to form an electrostatic latent image on each of the photosensitive drums 1a to 1d according to the image data. The developing devices 3a to 3d are filled with a predetermined amount of a two-component developer (hereinafter, also simply referred to as a developer) containing toners of cyan, magenta, yellow, and black by toner containers 4a to 4d. The toner in the developer is supplied onto the photosensitive drums 1a to 1d by 3a to 3d, and adheres electrostatically. As a result, a toner image corresponding to the electrostatic latent image formed by exposure from the exposure device 5 is formed.

  Then, an electric field is applied at a predetermined transfer voltage between the primary transfer rollers 6a to 6d and the photosensitive drums 1a to 1d by the primary transfer rollers 6a to 6d, and cyan, magenta, yellow and yellow on the photosensitive drums 1a to 1d are applied. The black toner image is primarily transferred onto the intermediate transfer belt 8. Toner and the like remaining on the surfaces of the photosensitive drums 1a to 1d after the primary transfer are removed by the cleaning devices 7a to 7d.

  The transfer paper P to which the toner image is transferred is accommodated in a paper cassette 16 arranged at a lower part in the image forming apparatus 100, and the transfer paper P is supplied to a predetermined position via a paper feed roller 12a and a pair of registration rollers 12b. At a timing, the sheet is conveyed to a nip (secondary transfer nip) between the secondary transfer roller 9 provided adjacent to the intermediate transfer belt 8 and the intermediate transfer belt 8. The transfer paper P on which the toner image has been secondarily transferred is conveyed to the fixing unit 13.

  The transfer paper P conveyed to the fixing unit 13 is heated and pressed by the fixing roller pair 13a, so that the toner image is fixed on the surface of the transfer paper P, and a predetermined full-color image is formed. The transfer paper P on which the full-color image is formed is discharged to the discharge tray 17 by the discharge roller pair 15 as it is (or after being distributed to the reversing conveyance path 18 by the branching section 14 and forming images on both sides).

  FIG. 2 is a side sectional view of the developing device 3a according to the embodiment of the present invention, which is mounted on the color printer 100. Note that FIG. 2 shows a state viewed from the back side of FIG. 1, and the arrangement of each member in the developing device 3a is reversed left and right from FIG. In the following description, the developing device 3a arranged in the image forming unit Pa in FIG. 1 is exemplified, but the configuration of the developing devices 3b to 3d arranged in the image forming units Pb to Pd is basically the same. Therefore, the description is omitted.

  As shown in FIG. 2, the developing device 3a includes a developing container (casing) 20 that stores a two-component developer (hereinafter, simply referred to as a developer) including a toner and a magnetic carrier. The agitation transfer chamber 21 and the supply transfer chamber 22 are partitioned by the partition wall 20a. The stirring and transporting chamber 21 and the supply and transporting chamber 22 are provided with a stirring and transporting screw 25a for mixing toner (positively charged toner) supplied from the toner container 4a (see FIG. 1) with a carrier, stirring and charging the toner, and a supply and transporting screw. Screws 25b are provided rotatably.

  The developer is conveyed in the axial direction (a direction perpendicular to the paper surface of FIG. 2) while being stirred by the stirring and conveying screw 25a and the supply and conveying screw 25b, and passes through a developer (not shown) formed at both ends of the partition wall 20a. It circulates between the agitation transfer chamber 21 and the supply transfer chamber 22 via a path. That is, a developer circulation path is formed in the developing container 20 by the agitation transfer chamber 21, the supply transfer chamber 22, and the developer passage.

  The developing container 20 extends obliquely upward to the right in FIG. 2, and a toner supply roller 30 (developer carrier) is disposed above the supply / conveyance screw 25 b in the developing container 20. The developing roller 31 is disposed to face diagonally above. The developing roller 31 is opposed to the photosensitive drum 1a (see FIG. 1) on the opening side (the right side in FIG. 2) of the developing container 20, and the toner supply roller 30 and the developing roller 31 are around the respective rotation axes. At 2, it rotates counterclockwise.

  In the stirring and transporting chamber 21, a toner density sensor 28 is disposed so as to face the stirring and transporting screw 25a. The toner density sensor 28 detects the ratio (T / C) of the toner to the carrier in the developer. For example, a magnetic permeability sensor that detects the magnetic permeability of the developer in the developing container 20 is used. In this embodiment, the toner density sensor 28 detects the magnetic permeability of the developer, and outputs a voltage value corresponding to the detection result to a control unit (not shown) described later. The toner density is determined from the output value of the toner density sensor 28. The control unit transmits a control signal to a toner supply motor (not shown) in accordance with the determined toner concentration, and transfers a predetermined amount of toner from the toner container 4a to the stirring and transporting chamber 21 via the toner supply port (not shown). The toner is supplied.

  The toner supply roller 30 includes a nonmagnetic rotating sleeve that rotates counterclockwise in FIG. 2 and a fixed magnet body having a plurality of magnetic poles included in the rotating sleeve.

  The developing roller 31 includes a cylindrical developing sleeve that rotates in a counterclockwise direction in FIG. 2 and a developing roller-side magnetic pole fixed in the developing sleeve. The toner supply roller 30 and the developing roller 31 They face each other with a predetermined gap at the facing position (facing position). The developing roller-side magnetic pole has a polarity different from that of the magnetic pole (main pole) of the fixed magnet body facing the magnetic pole.

  In addition, the cutting blade 33 is attached to the developing container 20 along the longitudinal direction of the toner supply roller 30 (the direction perpendicular to the paper surface of FIG. 2). 2 (counterclockwise direction in FIG. 2), it is positioned upstream of the position where the developing roller 31 and the toner supply roller 30 face each other. A slight gap (gap) is formed between the tip of the ear cutting blade 33 and the surface of the toner supply roller 30.

  A DC voltage (hereinafter, referred to as Vslv (DC)) and an AC voltage (hereinafter, referred to as Vslv (AC)) are applied to the developing roller 31, and a DC voltage (hereinafter, referred to as Vmag (DC)) is applied to the toner supply roller 30. ) And an AC voltage (hereinafter, referred to as Vmag (AC)). These DC voltage and AC voltage are applied to the developing roller 31 and the toner supply roller 30 from a developing bias power supply via a bias control circuit (both not shown).

  As described above, while the developer is stirred by the stirring and conveying screw 25a and the supply and conveying screw 25b, the developer is circulated through the stirring and conveying chamber 21 and the supply and conveying chamber 22 in the developing container 20, and the toner is charged. The developer is transported to the toner supply roller 30. Then, a magnetic brush (not shown) is formed on the toner supply roller 30, and the magnetic brush on the toner supply roller 30 is regulated in layer thickness by the cutting blade 33. The thin toner layer is formed on the developing roller 31 by a potential difference ΔV between Vmag (DC) applied to the toner supply roller 30 and Vslv (DC) applied to the developing roller 31 and a magnetic field.

  The thin toner layer formed on the developing roller 31 by the contact with the magnetic brush on the toner supply roller 30 is conveyed to the opposing portion (opposed area) between the photosensitive drum 1a and the developing roller 31 by the rotation of the developing roller 31. You. Since Vslv (DC) and Vslv (AC) are applied to the developing roller 31, the toner flies due to a potential difference between the developing roller 31 and the photosensitive drum 1a, and the electrostatic latent image on the photosensitive drum 1a is developed. .

  The toner remaining without being used for the development is transported again to a portion where the developing roller 31 and the toner supply roller 30 are opposed to each other, and is collected by a magnetic brush on the toner supply roller 30. Then, the magnetic brush is peeled off from the toner supply roller 30 at the same polar portion of the fixed magnet body, and then falls into the supply / transport chamber 22.

  Thereafter, a predetermined amount of toner is replenished from a toner replenishing port (not shown) based on the detection result of the toner density sensor 28, and is again uniformly circulated at an appropriate toner density while circulating through the supply conveyance chamber 22 and the stirring conveyance chamber 21. It becomes a charged two-component developer. The developer is again supplied onto the toner supply roller 30 by the supply / conveyance screw 25b to form a magnetic brush, and is conveyed to the ear cutting blade 33.

  In the vicinity of the developing roller 31 on the right side wall of the developing container 20 in FIG. 2, a toner receiving support member 35 having a triangular cross section protruding inside the developing container 20 is provided. As shown in FIG. 2, the toner receiving and supporting member 35 is disposed along the longitudinal direction of the developing container 20 (a direction perpendicular to the paper surface of FIG. 2). A wall is formed to face the developing roller 31 and to be inclined downward from the developing roller 31 toward the toner supply roller 30. On the upper surface of the toner receiving support member 35, a toner receiving member 37 that receives toner that is peeled off from the developing roller 31 and falls is attached along the longitudinal direction.

  FIG. 3 is a perspective view of the toner receiving and supporting member 35 used in the developing devices 3a to 3d of the present embodiment as viewed from the inside of the developing container 20 (left side in FIG. 2), and FIG. It is a perspective view.

  The toner receiving member 37 is made of sheet metal, has a bent shape with a bent portion 37a formed along the longitudinal direction, and has a toner receiving surface 37b opposed to the developing roller 31 (see FIG. 2) with the bent portion 37a interposed therebetween. , And a substantially vertical toner falling surface 37 c facing the toner supply roller 30. The toner receiving member 37 is supported by a resin supporting member main body 36 via two coil springs 40. Specifically, an engagement portion 37d in which one end of the coil spring 40 engages is formed by bending at two places at both ends of the toner receiving member 37, and a spring pedestal 39 is provided at the other end of the coil spring 40 (see FIG. 9). Is installed. The spring pedestal 39 is held by a spring pedestal holding portion 36 a of the support member main body 36. Further, a holder holding portion 37e for supporting the vibration generator 42 is formed at a substantially central portion of the toner receiving member 37 by bending.

  A vibration motor 43 (see FIG. 5), a circuit for controlling the driving of the vibration motor 43, and electronic components (not shown) are mounted in the vibration generator 42, and supplies power to the vibration motor 43. Lead wire 45 is connected.

  Sheet members 41a and 41b (see FIG. 8) are attached to the surface of the toner receiving member 37. The sheet members 41 a and 41 b are formed of a material to which toner is less likely to adhere than the toner receiving member 37 in order to suppress toner adhesion to the toner receiving member 37. Examples of the material of the sheet members 41a and 41b include a fluororesin sheet.

  The sheet member 41 a is attached so as to cover the surface of the toner receiving member 37 (toner falling surface 37 c) including the boundary between the support member main body 36 on the side of the cutting blade 33 and the toner receiving member 37. The sheet member 41b is attached so as to cover the entire area of the toner receiving surface 37b including the boundary between the support member main body 36 on the seal member 44 side and the toner receiving member 37, the engaging portion 37d, and the holder holding portion 37e. I have. The sheet members 41a and 41b suppress the toner from adhering to the toner receiving surface 37b and the toner falling surface 37c, and transfer the toner from the boundary between the support member main body 36 and the toner receiving member 37 into the toner receiving and supporting member 35. This prevents the vibration motor 43 from malfunctioning due to the entry or the toner entry.

  At the upper end of the support member main body 36, a film-shaped seal member 44 is provided. The seal member 44 extends in the longitudinal direction of the support member main body 36 (the left-right direction in FIG. 3) so that the front end portion contacts the surface of the photosensitive drum 1a, and is inside the developing container 20 (see FIG. 2). It has a function of shielding toner from leaking to the outside.

  Further, a weight 60 is attached to the toner receiving member 37 on the back surface side of the toner receiving surface 37b. The weight 60 equalizes the amplitude distribution when the toner receiving member 37 is vibrated in the longitudinal direction. The material of the weight 60 is not particularly limited. Here, a material obtained by dropping an adhesive and solidifying the adhesive is used. The detailed configuration of the weight 60 will be described later.

  FIG. 5 is an exploded perspective view of the vibration generator 42 in FIG. The vibration generator 42 includes a vibration motor 43, a motor mounting plate 42a to which the vibration motor 43 is fixed, and a cover member 42b, and a vibration weight 50 is fixed to an output shaft 43a of the vibration motor 43. . Further, the vibration motor 43 is fixed so that the output shaft 43 a extends along the longitudinal direction of the toner receiving member 37.

  FIG. 6 is a front view of the vibration motor 43, and FIG. 7 is a side view of the vibration motor 43 as viewed from the vibrating weight 50 side. When viewed from the direction of the output shaft 43a of the vibration motor 43 (rightward in FIG. 6), the vibrating weight 50 has a cam shape in which a notch 50a is formed in a part of a disk as shown in FIG. And has an asymmetric shape with respect to the output shaft 43a. When the output shaft 43a rotates at a speed higher than a predetermined speed, a non-uniform centrifugal force is applied to the vibrating weight 50 because the centrifugal force acting on the cutout portion 50a is smaller than that of other portions. By transmitting the centrifugal force to the output shaft 43a, the vibration motor 43 vibrates. The shape of the vibrating weight 50 is not limited to the cam shape, but may be any shape that shifts the center of gravity with respect to the output shaft 43a.

  FIGS. 8 and 9 are side sectional views showing the internal configuration of the toner receiving and supporting member 35 used in the developing device 3a of the present embodiment. 8 shows a cross section of the toner receiving and supporting member 35 in the vicinity of the vibration motor 43 (a cross section taken along line XX 'in FIG. 4), and FIG. 9 shows a cross section of the toner receiving and supporting member 35 including the coil spring 40 (YY' in FIG. 4). (Section in the direction of the arrow).

  The toner receiving member 37 is inclined such that the toner receiving surface 37b facing the developing roller 31 is inclined upward from the toner supply roller 30 toward the photosensitive drum 1a, and the toner drop surface 37c facing the toner supply roller 30 is provided. Are arranged substantially vertically. Further, the angle and the surface roughness (coefficient of friction) of the toner receiving surface 37b are adjusted so that the toner accumulated on the toner receiving surface 37b does not drop naturally due to gravity, vibration caused by driving of the developing device 3a, or the like.

  As shown in FIGS. 8 and 9, only the edge 37 f of the toner receiving member 37 on the toner supply roller 30 side is in contact with the support member main body 36, and the edge 37 g on the opposite side (the photosensitive drum 1 a side) is It is a free end. A substantially central portion of the toner receiving surface 37b in the width direction (the left-right direction in FIG. 8) is supported by the support member main body 36 via the vibration generator 42. Thus, the toner receiving member 37 is configured to be swingable about the edge 37f. Further, the vibration motor 43 is arranged such that the output shaft 43 a is substantially parallel to the longitudinal direction of the toner receiving member 37.

  By rotating the output shaft 43a of the vibration motor 43 at high speed (for example, about 10,000 rpm) during non-image formation, the vibration weight 50 also rotates at high speed together with the output shaft 43a. At this time, since an uneven centrifugal force is applied to the excitation weight 50, the vibration generator 42 including the vibration motor 43 and the motor mounting holder 42 vibrates via the output shaft 43a. Then, the toner receiving member 37 to which the vibration generator 42 is attached also vibrates. Specifically, the toner receiving surface 37b of the toner receiving member 37 vibrates so that the amplitude increases toward the edge 37g with the edge 37f as a fulcrum. Due to the vibration of the toner receiving member 37, the toner deposited on the side of the edge 37g of the toner receiving surface 37b jumps up to the side of the edge 37f (in the direction of the white arrow), and moves little by little to the side of the edge 37f.

  Due to the vibration of the toner receiving surface 37b, as shown in FIG. 9, the toner T deposited on the toner receiving surface 37b slides down (in the direction of the white arrow in FIG. 9) along the inclination of the toner receiving surface 37b, and becomes substantially vertical. The toner freely falls into a region R sandwiched between the toner falling surface 37c and the toner supply roller 30. Part of the toner that has fallen into the region R passes through the gap between the ear cutting blade 33 and the toner supply roller 30 and falls into the supply / transport chamber 22.

  In the present embodiment, the developing roller 31 and the toner supply roller 30 are rotated in the opposite direction (clockwise direction in FIG. 8) during non-image formation in order to return the toner dropped in the region R to the supply conveyance chamber 22 during non-image formation. Rotate (reverse rotation). By rotating the toner supply roller 30 in the reverse direction, the toner that has fallen into the region R and accumulated on the tip of the ear-cutting blade 33 is scraped off by the magnetic brush of the toner supply roller 30 and rotates along with the surface of the toner supply roller 30. Then, after passing through the gap between the toner supply roller 30 and the ear-cutting blade 33 and being peeled off from the toner supply roller 30 at the same pole portion of the fixed magnet body, it is forcibly returned to the supply / transport chamber 22.

  When the developing roller 31 and the toner supply roller 30 are rotated in the reverse direction, the magnetic force of the magnetic pole (regulation pole) of the fixed magnet body facing the ear cutting blade 33 so that the magnetic brush formed on the toner supply roller 30 becomes longer. By adjusting the arrangement, the effect of scraping off the toner accumulated on the tip of the ear cutting blade 33 is enhanced. When the developing roller 31 and the toner supply roller 30 are rotated in the reverse direction, the stirring and conveying screw 25a and the supply and conveying screw 25b also rotate in the reverse direction, so that the developer in the developing container 20 overflows from the toner supply port, or the developing container 20 There is a possibility that the bias of the developer occurs in the inside and noise of the toner density sensor 28 occurs. Therefore, after the developing roller 31 and the toner supply roller 30 are reversely rotated, it is preferable that the developing roller 31 and the toner supply roller 30 are sequentially rotated for a predetermined time.

  When the toner receiving member 37 is vibrated, the toner supply roller 30 and the developing roller 31 can be rotated in the forward direction. By rotating the toner supply roller 30 in a forward direction, a part of the toner that has fallen from the toner receiving surface 37b to the region R adheres to the magnetic brush on the toner supply roller 30. The remaining toner that has not adhered to the magnetic brush on the toner supply roller 30 passes through the gap between the toner supply roller 30 and the cutting blade 33 and falls into the supply / transport chamber 22.

  In the present embodiment, the outer peripheral surface of the output shaft 43a of the vibration motor 43 on the side facing the toner receiving member 37 of the output shaft 43a is supported from the free end (the edge 37e) of the toner receiving member 37 by the fulcrum (the edge 37d). (In the counterclockwise direction in FIG. 8). By rotating the output shaft 43a in this direction, the toner receiving member 37 vibrates so as to move the toner accumulated on the toner receiving surface 37b from the edge 37g to the edge 37f.

  On the other hand, when the output shaft 43a is rotated in the reverse direction (clockwise direction in FIG. 8), the toner is moved so as to rise from the edge 37f to the edge 37g by the vibration of the toner receiving member 37. Therefore, the toner accumulated on the toner receiving surface 37b does not slip down. Therefore, by rotating the output shaft 43a of the vibration motor 43 as in the present embodiment, the toner accumulated on the toner receiving surface 37b can be effectively dropped into the region R along a downward gradient.

  Further, since the sheet members 41a and 41b are attached to the surface of the toner receiving member 37, it is possible to suppress the toner from adhering to the toner receiving member 37. Further, since the sheet members 41a and 41b are attached so as to cover the boundary between the support member main body 36 and the toner receiving member 37, and the engaging portion 37d and the holder holding portion 37e, the support member main body 36 and the toner receiving member 37 are attached. It is also possible to prevent toner from entering the inside of the toner receiving and supporting member 35 from the boundary with 37, and prevent the vibration motor 43 from malfunctioning due to the toner entry.

  The timing for oscillating the toner receiving member 37 may be performed every time the printing operation is completed, or may be performed at a predetermined time, such as when the number of prints reaches a predetermined number or when the temperature in the developing device 3a becomes equal to or higher than a predetermined value. It may be performed at timing. Further, the timing at which the toner receiving member 37 is vibrated and the timing at which the developing roller 31 and the toner supply roller 30 are rotated backward (or forward) may be the same or different. Further, by vibrating the toner receiving member 37 each time the predetermined number of printed sheets is reached, the vibration of the toner receiving member 37 is automatically executed according to the number of printed sheets. Therefore, it is not necessary for the user to manually set the vibration of the toner receiving member 37, and it is possible to avoid setting errors, forgetting to set, or performing unnecessary vibration.

  By the way, the amplitude of the toner receiving member 37 is determined by the relationship between the resonance frequency of the toner receiving member 37 and the rotation speed (rotation frequency) of the vibration motor 43. FIGS. 10 to 14 show the distribution of the amplitude in the longitudinal direction of the toner receiving member 37 at the resonance frequency of the toner receiving member 37 that appears when the rotation speed of the vibration motor 43 is changed. The toner receiving member 37 is formed by bending a stainless steel plate having a thickness of 0.2 mm, and has a length of 303 mm, a width of the toner receiving surface 37 b of 7.4 mm, a width of the toner falling surface 37 c of 2.5 mm, and a toner falling surface. The angle of the toner receiving surface 37b with respect to 37c is 120 °. Further, the vibration generator 42 is mounted slightly near the rear end from the center in the longitudinal direction of the toner receiving member 37.

  FIG. 10 is a graph showing the distribution of the amplitude of the toner receiving member 37 when the vibration motor 43 is rotated at 80.9 Hz (4844 rpm). As shown in FIG. 10, at the first resonance frequency of 80.9 Hz, the toner receiving member 37 extends over the entire length of the toner receiving member 37 in the longitudinal direction even though both ends in the longitudinal direction are free ends. The amplitude is small.

  FIG. 11 is a graph showing the distribution of the amplitude of the toner receiving member 37 when the vibration motor 43 is rotated at 116.8 Hz (6944 rpm). As shown in FIG. 11, at 116.8 Hz, the central portion in the longitudinal direction of the toner receiving member is an antinode of amplitude, and both ends are nodes of amplitude, but the amplitude in the central portion in the longitudinal direction is not large.

  FIG. 12 is a graph showing an amplitude distribution of the toner receiving member 37 when the vibration motor 43 is rotated at 135.2 Hz (8084 rpm). As shown in FIG. 12, at 135.2 Hz, both ends and the center of the toner receiving member in the longitudinal direction become amplitude nodes, and the amplitude increases at the middle between the both ends and the center. The amplitude is increased up to 40 μm in the middle portion up to the portion (the end farther from the vibration generator 42).

  FIG. 13 is a graph showing an amplitude distribution of the toner receiving member 37 when the vibration motor 43 is rotated at 138.8 Hz (8311 rpm). As shown in FIG. 13, at 138.8 Hz, both ends and the center in the longitudinal direction of the toner receiving member become nodes of the amplitude as in FIG. 11, but contrary to FIG. The amplitude is large in the middle portion up to the end near the device 42).

  FIG. 14 is a graph showing the amplitude distribution of the toner receiving member 37 when the vibration motor 43 is rotated at 195.1 Hz (11682 rpm). As shown in FIG. 14, at 195.1 Hz, the amplitude increases over the entire length of the toner receiving member, but the amplitude distribution is non-uniform and asymmetric in the longitudinal direction.

  It is sufficient that the amplitude of the toner receiving member 37 required to shake off the toner accumulated on the toner receiving surface 37b is about half (2 to 3 μm) of the particle diameter of the toner. On the other hand, if the amplitude of the toner receiving member 37 is too large, the toner accumulated on the toner receiving surface 37b will be scattered, and the toner will be scattered from the opening of the developing container 20 to the outside.

  Therefore, in the present embodiment, the weight 60 is attached to a position (the antinode of the amplitude) where the amplitude becomes maximum when the toner receiving member 37 is vibrated. By attaching the weight 60, the resonance frequency at which the amplitude of the toner receiving member 37 becomes maximum also changes. Therefore, by adjusting the number of rotations (rotation frequency) of the vibration motor 43 to the resonance frequency, the longitudinal direction of the toner receiving member 37 can be adjusted. Can be made substantially uniform. Thereby, the toner accumulated on the toner receiving surface 37b can be efficiently shaken down over the entire area in the longitudinal direction, and the scattering of the toner can be suppressed. Further, since the weight 60 is provided on the back surface side of the toner receiving surface 37b, there is no possibility that the toner accumulated on the toner receiving surface 37b is hard to slide down by the weight 60.

  Specifically, 1 g of an adhesive was dropped and solidified on the back surface side of the toner receiving surface 37b at positions of -100 mm (100 mm on the front side) and 100 mm (100 mm on the rear side) from the center in the longitudinal direction. A weight 60 was provided. As a result, the resonance frequency at which the amplitude of the toner receiving member 37 became maximum was slightly lowered from 135.2 Hz to 108 Hz. FIG. 15 shows the amplitude distribution in the longitudinal direction of the toner receiving member 37 when the vibration motor 43 is rotated at 108 Hz (6480 rpm).

  As shown in FIG. 15, it is confirmed that the amplitude of the toner receiving member 37 becomes 15 μm at the maximum by providing the weight 60, and the vibration in the middle portion where the amplitude is too large is suppressed, and the amplitude distribution is uniform. Was done.

  In addition, the present invention is not limited to the above embodiment, and various changes can be made without departing from the spirit of the present invention. For example, the shapes and configurations of the toner receiving support member 35 and the toner receiving member 37 described in the above-described embodiment are merely examples, and are not particularly limited to the above-described embodiment. be able to.

  For example, in the above-described embodiment, the weight 60 is formed by dropping an adhesive on the back side of the toner receiving surface 37b and curing the same. However, a metal piece or a resin piece is attached to the back side of the toner receiving surface 37b and the weight 60 is formed. It may be. In the above-described embodiment, the weights 60 are formed at both ends in the longitudinal direction of the toner receiving surface 37b. However, the position, the number, and the weight of the weights 60 are not limited thereto. Depending on the mounting position, the natural frequency of the toner receiving and supporting member 35, the number of positions where the amplitude is maximal (the antinode of the amplitude), etc., one or more positions where the amplitude distribution can be adjusted substantially uniformly can be adjusted. The weight 60 can be formed.

  INDUSTRIAL APPLICABILITY The present invention is applicable to an image forming apparatus including a developing device having a toner receiving member that faces a developing roller between a region where an image carrier and a developing roller oppose each other and a regulating blade. By utilizing the present invention, it is possible to provide a developing device capable of efficiently collecting the deteriorated toner accumulated on the toner receiving member while suppressing toner scattering to the outside of the developing device.

Pa to Pd Image forming unit 1a to 1d Photoconductor drum (image carrier)
3a to 3d Developing device 4a to 4d Toner container 20 Developing container (casing)
Reference Signs List 30 Toner supply roller 31 Developing roller 33 Ear cutting blade (regulating blade)
35 Toner receiving support member 35a Tip end 36 Support member main body 37 Toner receiving member 37a Bent portion 37b Toner receiving surface 37c Toner falling surface 40 Vibration generator 41a, 41b Sheet member 60 Weight 100 Color printer (image forming apparatus)

Claims (9)

A developing roller that is arranged to face the image carrier on which an electrostatic latent image is formed, and supplies toner to the image carrier in a region facing the image carrier;
A toner supply roller disposed to face the developing roller and supplying toner to the developing roller in a region facing the developing roller;
A regulating blade that is disposed to face the toner supply roller at a predetermined interval,
A casing accommodating the developing roller, the toner supply roller, and the regulating blade,
A toner receiving support member disposed in the casing and opposed to the developing roller or the toner supply roller between the regulating blade and the image carrier,
A toner receiving member that is disposed so as to be inclined downward from the image bearing member side toward the toner supply roller side along the longitudinal direction of the toner receiving support member and has a toner receiving surface that receives toner dropped from the developing roller; When,
A vibration generator for vibrating the toner receiving member,
In a developing device provided with
A developing device is characterized in that a weight is provided at one or more positions where the amplitude in the longitudinal direction becomes maximum when the toner receiving member is vibrated when the toner receiving member is vibrated.   2. The developing device according to claim 1, wherein an attachment location and a weight of the weight are determined such that an amplitude of the toner receiving member is substantially uniform in a longitudinal direction. 3.   3. The developing device according to claim 1, wherein the weight is formed by curing a liquid adhesive attached to a back surface of the toner receiving surface. 4. The vibration generator has a vibration motor fixed to the back surface of the toner receiving member, and a vibration weight fixed so that the center of gravity is shifted with respect to an output shaft of the vibration motor,
4. The developing device according to claim 1, wherein a rotation frequency of the vibration motor is adjusted so that an amplitude of the toner receiving member is substantially uniform in a longitudinal direction. The vibration motor is fixed to a back surface of the toner receiving member so that an output shaft is substantially parallel to a longitudinal direction of the toner receiving member,
The toner receiving member is swingably supported with an edge on the toner supply roller side as a fulcrum and an edge on the image carrier side as a free end,
An outer peripheral surface of an output shaft of the vibration motor on a side facing the toner receiving member rotates the output shaft in a direction moving from a free end side of the toner receiving member toward a fulcrum. Item 5. The developing device according to Item 4.   The developing device according to claim 1, wherein the developing roller and the toner supply roller are rotated in a direction opposite to a direction during image formation during driving of the vibration generating device.   7. The developing device according to claim 6, wherein after the driving of the vibration generating device is completed, the developing roller and the toner supply roller are continuously rotated for a predetermined time in the same direction as that during image formation.   The developing device according to claim 1, wherein the developing roller and the toner supply roller are rotated in the same direction as that during image formation while the vibration generating device is being driven.   An image forming apparatus comprising the developing device according to claim 1.