JP2006235474A - Developing device, process cartridge, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To not only sufficiently mix a replenished toner with a developer in a developing case by agitation but also quickly uniformly distribute the replenished toner in the developer by properly charging the replenished toner, to prevent toner scattering, in a developing device using the two-component developer. <P>SOLUTION: In this developing device 12, a developing sleeve (developer carrier) 28, two carrying paths 30 and 31 provided in parallel with the developing sleeve, a partition 34 which isolates the carrying paths from each other with connection paths 32 and 33 left on the outside of both ends, and agitating and carrying screws (first agitating and carrying members) 35 and 36 stored in the carrying paths respectively are provided in a developing case 27, and the developer is agitated and carried in such way that the developer is delivered in the connection paths and is circulated between two carrying paths by rotating the screws. In this developing device, a paddle shape 44 is provided below the first agitating and carrying screw 35 closer to the developing sleeve correspondingly to the connection path 32, and a toner supply position 42 for the replenished toner from the outside is provided in a portion of this paddle shape. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, or a complex machine thereof. Among them, in particular, with the rotation of the image carrier, a latent image is formed on the image carrier, and the developing device attaches toner to visualize the latent image, and the visible toner image is directly or intermediately formed. The present invention relates to an image forming apparatus such as monochrome or color that transfers an image indirectly through a transfer body and records an image on a recording medium such as paper or an OHP film. The present invention also relates to a process cartridge in which at least an image carrier and a developing device are integrated in such an image forming apparatus, and can be detachably attached to the main body of the image forming apparatus. The present invention also relates to a developing device that uses a two-component developer including a toner and a carrier, attaches the toner to the image carrier, and visualizes the latent image on the image carrier.

  Conventionally, among image forming apparatuses such as copying machines and printers, an electrophotographic type includes a charging device, an exposure device, a developing device, a transfer device, a cleaning device, etc. around a drum-like or belt-like image carrier. Arranged. Then, with the rotation of the image carrier, an electrostatic latent image is formed on the surface of the image carrier by charging with a charging device and writing with an exposure device, and toner is attached to the electrostatic latent image with a developing device. The toner image formed by the visualization was transferred directly or indirectly via an intermediate transfer member, and the image was recorded on a recording medium such as paper or an OHP film.

  As developing devices, there are known a one-component developing type using a one-component developer consisting only of toner and a two-component developing type using a two-component developer consisting of toner and carrier. The two-component developing system has a configuration as shown in FIG. 8, for example.

  Reference numeral 1 in the figure denotes a developing case having an elongated opening 2. A developing sleeve 3 is rotatably provided in the developing case 1 with a part exposed from the opening 2. In the developing sleeve 3, a magnet roller 4 having NS magnetic poles alternately on its peripheral surface is fixed. Around the developing sleeve 3, a regulating member 5 is supported by the developing case 1 with the tip close to the peripheral surface.

  In the developing case 1, two agitating / conveying screws 6, 7 are rotatably arranged in parallel with the developing sleeve 3 as agitating / conveying members. In the developing case 1, a new supply toner supply port 8 is opened at an upstream position of the stirring and conveying screw 7 on the side far from the developing sleeve 3, and the toner is directed under the stirring and conveying screw 7 into the developing case 1. A density detection sensor 9 was attached.

  As a result, during development, the developing sleeve 3 and the two agitating and conveying screws 6 and 7 are both rotated counterclockwise in the drawing, and the two-component developer is agitated and conveyed by the two agitating and conveying screws 6 and 7. While being circulated, the developer sleeve 3 is fed to the developing sleeve 3 and the amount of the developer adhering to the developing sleeve 3 is regulated by the regulating member 5 to guide a predetermined amount of developer to the developing region. The toner is attached to an image carrier (not shown) provided to face 3 and the electrostatic latent image on the image carrier is visualized.

  When the toner density in the developing case 1 falls below a certain level as the toner is supplied to the image carrier and the developer is consumed, the toner density detection sensor 9 detects the reduction in the toner density and is not shown. A predetermined amount of toner is replenished by driving the toner conveying means of the toner replenishing device, conveying new toner from a toner container (not shown), and dropping onto the developer in the developing case 1 from the replenishing port 8 by its own weight. It was.

  The replenishing toner is mixed with the developer in the developing case 1 while being agitated and conveyed by the two agitating and conveying screws 6 and 7, and is uniformly dispersed and charged in the developer, and is attached to the developing sleeve 3. Then, by regulating the amount of the developer adhered by the regulating member 5, a predetermined amount of developer is guided to the development area, and toner is adhered to an image carrier (not shown) in the development area, so that the image on the image carrier. The electrostatic latent image was visualized.

  As described above, the two agitating and conveying screws 6 and 7 are provided in parallel with the developing sleeve 3, and the two agitating and conveying screws 6 and 7 are circulated by rotating them to agitate and convey the developer. The developing device as shown has the advantage of being space-saving and excellent in the agitation of the developer, and also excellent in transportability.

Japanese Patent Laid-Open No. 2002-066631 JP 2004-69789 A JP 2004-69940 A

However, in the conventional developing apparatus as described above,
(1) When a large amount of toner is consumed and a large amount of replenishment toner is used, such as when an image having a high image area ratio is continuously formed or when an image is recorded on a sheet of A2 or higher. (2) Low temperature When the charge amount of the toner in the developer in the developing case 1 is increased, such as in a low humidity environment, and the binding force with the carrier is increased, making it difficult for the replenishing toner to come into contact with the carrier. When the ability to charge the toner is reduced, such as when the carrier is deteriorated, the replenishment toner is not sufficiently mixed with the developer in the developing case 1 without being properly charged without stirring. There was a problem of being sent toward the developing sleeve 3.

  Sometimes the replenished toner moves to the developing sleeve 3 with little mixing and charging so as to slide on the developer surface in the developing case 1, and in such a case, toner scattering occurs, There has been a problem that the background quality is deteriorated to deteriorate the image quality, or the image forming apparatus is contaminated by scattering from the developing device. Further, the toner does not uniformly disperse in the developer and may move to the developing sleeve 3 in a state in which the toner density varies, resulting in a poor detection of the toner density in the developer, and the toner cannot be replenished accurately. There was a problem.

  In order to solve such a problem, it is conceivable to increase the stirring and conveying force of the developer in the developing case 1, but this causes a new problem that the deterioration of the developer is accelerated. Although it is conceivable to lengthen the stirring and conveying members such as the stirring and conveying screws 6 and 7 so that the replenishing toner is mixed with the developer in the developing case 1, there is a problem that the size of the developing device and the image forming apparatus is increased. was there.

  Furthermore, it is known that a paddle shape is provided between the stirring and conveying screw pitches, and the developer is stirred in the paddle shape. However, in this case, there is a problem in that the developer conveying performance by the agitating and conveying screw is deteriorated, and there is a problem such as insufficient supply of the developer to the developing sleeve.

  SUMMARY OF THE INVENTION Accordingly, a first object of the present invention is to solve the above-mentioned problems when toner is replenished in a two-component developing type developing device, to increase the developer agitating and conveying force, and to lengthen the agitating and conveying member. The toner to be supplied is sufficiently mixed with the developer in the developer case and properly charged by stirring without being deteriorated in developer transport performance, and quickly and uniformly dispersed in the developer. The object is to eliminate the possibility of toner scattering.

  A second object of the present invention is to provide a developing device of a two-component development system by accurately guiding the replenishment toner to a charging position with a member provided in itself, thereby increasing the stirring and conveying force of the developer or lengthening the stirring and conveying member. The toner to be supplied is sufficiently mixed with the developer in the developer case and properly charged by stirring to disperse quickly and uniformly in the developer. This eliminates the possibility of toner scattering.

  A third object of the present invention is to improve the stirring and conveying force of the developer by accurately guiding the replenishment toner to the charging position with an external member attached to the developing case in the two-component developing type developing device, The toner to be mixed is sufficiently mixed with the developer in the developer case and properly charged by stirring, without increasing the length of the toner or reducing the developer transport performance, and quickly and uniformly in the developer. The object is to eliminate the risk of toner scattering by dispersion.

  A fourth object of the present invention is to increase the agitating / conveying force of a developer or agitating / conveying member in a two-component developing type developing device while preventing uncharged toner from splashing outside through the opening of the developing case. The toner to be mixed is sufficiently mixed with the developer in the developer case and properly charged by stirring, without increasing the length of the toner or reducing the developer transport performance, and quickly and uniformly in the developer. The object is to eliminate the risk of toner scattering by dispersion.

  A fifth object of the present invention is to provide a process cartridge provided with a developing device having the above-mentioned object.

  A sixth object of the present invention is to provide an image forming apparatus provided with a developing device having the above-mentioned object.

  A seventh object of the present invention is to stir and convey a developer in an image forming apparatus while preventing an excessive increase in pressure of a toner replenishment path forming member that replenishes toner to the developing apparatus and preventing toner scattering of uncharged toner. The replenishment toner is sufficiently mixed with the developer in the developing case and properly charged by stirring without increasing the force, lengthening the stirring and conveying member, or reducing the developer conveying performance. The object is to eliminate the possibility of toner scattering by rapidly and uniformly dispersing in the developer.

  An eighth object of the present invention is to increase the agitating and conveying force of the developer in the image forming apparatus while facilitating maintenance and preventing the toner replenishment path forming member from excessively increasing the pressure and preventing the toner of the uncharged toner from scattering. Without stirring, lengthening the agitating / conveying member, or degrading the developer conveying performance, the replenished toner is sufficiently mixed with the developer in the developing case and properly charged by stirring. In other words, it is possible to quickly and uniformly disperse the toner and to prevent toner scattering.

  According to the first aspect of the present invention, there is provided a developer carrier such as a developing sleeve that attaches toner to a drum-like or belt-like image carrier and visualizes a latent image on the image carrier, A first conveyance path on the side close to the developer carrier and a second conveyance path on the side far from the developer carrier, and the space between the first conveyance path and the second conveyance path, which are provided in parallel with the developer carrier, are connected to both ends. A partition wall for partitioning leaving a passage, a first agitating and conveying member such as a first agitating and conveying screw stored in the first conveying path, and a second agitating and conveying screw or the like accommodated in the second conveying path. A developing and conveying member is provided in the developing case, and the first agitating and conveying member and the second agitating and conveying member are rotated to pass through the communication path and circulate between the first conveying path and the second conveying path. A developing device that stirs and conveys the developer. In such a developing device, in order to achieve the first object described above, a paddle shape is provided at a downstream position of the first stirring and conveying member corresponding to the communication path, and the paddle-shaped portion is externally provided. A supply toner supply position such as new toner to be supplied or recycled toner is provided. Here, the paddle shape is provided with a plurality of blades whose blade surfaces are parallel to the axis in a radial pattern around the shaft, and passes the developer through the communication path between the first stirring and conveying member. It is.

  Then, the replenishing toner is put into the paddle-shaped portion at the downstream position of the first stirring and conveying member, and immediately stirred in the paddle shape and mixed with the developer in the developing case.

  According to a second aspect of the present invention, in order to achieve the second object described above, in the developing device according to the first aspect, a toner replenishing port for replenishing replenished toner to the developing case, and a toner replenishing port A guide member for guiding the replenished replenished toner to the charging position is provided. The guide member is provided integrally with the developing case, or is formed separately and attached to the developing case.

  Then, the toner is supplied from the toner supply port of the developing case, and the supplied toner is guided to the charging position by the guide member.

  According to a third aspect of the present invention, in order to achieve the third object described above, in the developing device according to the first aspect, an outlet of a toner replenishment path forming member that is attached to the developing case and replenishes replenishment toner is provided in the developing device. It is provided at the loading position. Here, the toner replenishment path forming member forms a toner replenishment path, and replenishes the developing device with toner through the toner replenishment path by being attached to the developing case.

  Then, a toner replenishment path forming member is attached to the developing case, and toner is introduced into the developing device from the outlet of the toner replenishment path forming member.

  According to a fourth aspect of the present invention, in order to achieve the fourth object described above, in the developing device according to any one of the first to third aspects, the developer carrying member is exposed by being provided in the developing case. The paddle shape is provided on the downstream side of the first agitation transport member from a position corresponding to the opening.

  Then, the supply position of the replenishment toner provided in the paddle-shaped portion is moved away from the opening of the developing case.

  According to a fifth aspect of the present invention, there is provided a process cartridge comprising the developing device according to any one of the first to fourth aspects, in order to achieve the fifth object described above. The process cartridge is constituted by integrating at least the image carrier and the developing device, and is detachable in a lump with respect to the image forming apparatus main body.

  According to a sixth aspect of the present invention, there is provided a copying machine, a printer, a facsimile, or the like, comprising the developing device according to any one of the first to fourth aspects to achieve the sixth object. This is a monochrome or color image forming apparatus such as a multifunction peripheral.

  According to a seventh aspect of the invention, in order to achieve the seventh object described above, in the image forming apparatus according to the sixth aspect, air is passed through a toner replenishment path forming member that replenishes the developing device with replenishment toner. Is provided with a filter that does not allow toner to pass therethrough.

  A filter that allows air but not toner is used to prevent a rise in air pressure above a certain level in the toner supply path and the developing case.

  According to an eighth aspect of the present invention, in order to achieve the eighth object described above, in the image forming apparatus according to the seventh aspect, the toner replenishment path forming member is detachable from the developing device. is there.

  For example, when the toner bottle is replaced, the toner supply path forming member is removed from the developing device, and the filter provided in the toner supply path forming member is replaced.

  According to the first aspect of the present invention, in the two-component developing type developing device, the replenishing toner is put into the paddle-shaped portion at the downstream position of the first agitating and conveying member, and immediately stirred with the paddle, Since it is mixed with the developer, replenishment toner such as new toner and recycled toner is mixed well with the developer in the development case and charged appropriately so that the replenishment toner slides on the developer surface in the development case It is possible to reliably prevent toner scattering by eliminating the phenomenon of movement. Further, the toner can be uniformly dispersed quickly after being replenished in the developer to eliminate unevenness of the toner concentration, and the toner can be accurately replenished without the detection failure of the toner concentration in the developer. In addition, the developer agitating and conveying force in the developing case is increased to accelerate the deterioration of the developer, or the agitating and conveying member is lengthened so that the replenishment toner is mixed with the developer in the developing case, and the developing device, The conventional problems associated with toner replenishment can be solved without increasing the size of the image forming apparatus or reducing the developer transport performance by providing a stirring member in the middle of transport.

  According to the second aspect of the present invention, in the two-component developing type developing device, the toner is replenished from the toner replenishing port of the developing case, and the replenished toner is guided to the charging position by the guide member. The replenishing toner can be accurately guided to the charging position by a member provided in itself, and the replenishing toner can be sufficiently mixed with the developer in the developing case and appropriately charged to reliably prevent toner scattering. Further, the toner can be uniformly dispersed quickly after being replenished in the developer to eliminate unevenness of the toner concentration, and the toner can be accurately replenished without the detection failure of the toner concentration in the developer. Furthermore, in the case of replenishing toner without accelerating the deterioration of the developer, lengthening the agitating / conveying member, increasing the size of the developing device, and consequently the image forming apparatus, or reducing the developer conveying performance. Conventional problems can be solved.

  According to the third aspect of the present invention, in the two-component developing type developing device, the toner replenishment path forming member is attached to the developing case, and the toner is charged into the developing device from the outlet of the toner replenishment path forming member. The external member attached to the case can accurately guide the replenishment toner to the input position, and the replenishment toner can be sufficiently mixed with the developer in the developing case and appropriately charged to reliably prevent toner scattering. Further, the toner can be uniformly dispersed quickly after being replenished in the developer to eliminate uneven toner concentration, and the toner can be accurately replenished without the detection failure of the toner concentration in the developer. Furthermore, in the case where toner is replenished without accelerating the deterioration of the developer, lengthening the agitating / conveying member, increasing the size of the developing device, and hence the image forming apparatus, or reducing the developer conveying performance. Conventional problems can be solved.

  According to the fourth aspect of the present invention, in the two-component developing type developing device, the supply position of the replenishing toner provided in the paddle-shaped portion is moved away from the opening of the developing case, so that the first agitating / conveying member whose pressure is likely to rise In the downstream position, uncharged floating toner is prevented from splashing out of the developing case from the opening, and the replenishing toner is sufficiently mixed with the developer in the developing case and appropriately charged to reliably prevent toner scattering. be able to. Further, the toner can be uniformly dispersed quickly after being replenished in the developer to eliminate uneven toner concentration, and the toner can be accurately replenished without the detection failure of the toner concentration in the developer. Furthermore, in the case of replenishing toner without accelerating the deterioration of the developer, lengthening the agitating / conveying member, increasing the size of the developing device, and consequently the image forming apparatus, or reducing the developer conveying performance. Conventional problems can be solved.

  According to the invention described in claim 5, since the developing device according to any one of claims 1 to 4 is provided in the process cartridge, it is possible to provide a process cartridge provided with the developing device having the above-described effect. it can.

  According to the sixth aspect of the present invention, since the image forming apparatus includes the developing device according to any one of the first to fourth aspects, an image forming apparatus including the developing device having the above-described effect is provided. be able to.

  According to a seventh aspect of the present invention, in the image forming apparatus according to the sixth aspect, a filter that allows air to pass but does not allow toner to pass therethrough prevents an increase in air pressure above a certain level in the toner supply path and the developing case. Therefore, in addition to the effect of the invention of claim 6, the toner replenishment path forming member is prevented from excessively increasing the pressure to prevent the air pressure in the developing device from increasing, and the toner is not charged at a position where toner scattering is likely to occur. The effect of toner scattering prevention can be improved.

  According to the eighth aspect of the present invention, in the image forming apparatus according to the seventh aspect, the filter provided in the toner replenishment path forming member can be replaced by removing the toner replenishment path forming member from the developing device. In addition to the effects of the invention described in item 7, for example, when the filter is replaced in accordance with the replacement of the toner bottle, the toner supply path forming member is removed from the developing device, so that the filter can be easily replaced and the toner supply can be performed. An excessive increase in pressure of the path forming member can be prevented, and the toner scattering prevention effect of the uncharged toner can be improved.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 shows a schematic configuration of an internal mechanism of a main part in a monochrome electrophotographic image forming apparatus using a two-component developer.

  Reference numeral 10 in the figure may be a belt shape, but in the illustrated example, it is a drum-shaped photoconductor. Around the photosensitive member 10 shown as an example of the image carrier, a contact-type charging roller may be disposed above, but in this example, a non-contact charger-type charging device 11 is provided. In the rotation direction of the photoconductor 10 indicated by an arrow from the charging device 11, a developing device 12 is provided on the right side, a transfer conveyance device 13 is provided on the lower side, and a cleaning device 14 is provided on the left side. A neutralization device 15 is disposed between the cleaning device 14 and the charging device 11.

  The transfer / conveying device 13 includes two rollers 16 provided at intervals, and a conveying belt 17 wound around the rollers 16. A transfer position is provided between the photoconductor 10 and the conveyance belt 17, and a pair of guide plates 18 are provided toward the transfer position. A recording medium 20 such as paper or an OHP film is passed from the right through the lower side of the photoconductor 10. A transport path for transporting to the left is formed. Although not shown, a fixing device is installed downstream of the conveyance path. Reference numeral 21 denotes an exposure device that irradiates the photosensitive member 10 with the writing light L using a laser light source or the like between the charging device 11 and the developing device 12.

  Then, along with the clockwise rotation of the photosensitive member 10, the surface thereof is uniformly charged by the charging device 11, writing is performed by irradiating the writing light L by the exposure device 21 based on the image signal, and the surface of the photosensitive member 10 is written. An electrostatic latent image is formed. Then, the developing device 12 attaches toner to the surface of the photoconductor 10 to visualize the electrostatic latent image, and forms a toner image on the photoconductor 10.

  On the other hand, at an appropriate timing, the recording medium 20 is fed out one by one and put into the conveyance path, guided by the pair of guide plates 18 and sent to the transfer position. The toner image formed on the photoconductor 10 as described above is transferred to the recording medium 20 by the transfer / conveyance device 13 while being conveyed by the photoconductor 10 and the transfer / conveyance device 13. The recording medium 20 after the image transfer is conveyed leftward in the drawing by the transfer conveyance device 13 and guided to a fixing device (not shown). After fixing the transferred image, the recording medium 20 is discharged out of the main body of the image forming apparatus, for example. Stack on the paper output tray.

  On the other hand, the surface of the photoconductor 10 after the image transfer is initialized by removing the residual toner by scraping it off with a cleaning blade 22 which is a cleaning member of the cleaning device 14 and removing electricity with a static eliminating device 15. In preparation for the second image formation starting from the charging device 11 again. The residual toner removed by the cleaning device 14 is recovered by the recovery screw 23 and conveyed to a waste toner tank. Alternatively, the toner may be returned to the developing device 12 and reused as recycled toner.

  By the way, in the image forming apparatus as shown in the figure, if at least the image carrier and the developing device are integrated to form a process cartridge and can be detachably attached to the image forming apparatus main body at the time of life, failure or repair Maintenance at the time of jamming, jamming, cleaning, etc. can be facilitated, and the whole can be made small and downsized. Also in this example, the photosensitive member 10, the charging device 11, the developing device 12, the cleaning device 14, the static eliminating device 15 and the like are integrated to constitute the process cartridge 24.

  Now, the developing device 12 rotates a cylindrical developing sleeve 28 that is a developer carrying member, with a part exposed from the opening 26 in a developing case 27 having an elongated opening 26 facing the photoreceptor 10. Prepare freely. In the developing sleeve 28, although not shown, a magnet roller having NS magnetic poles alternately on the peripheral surface is fixed. Although not shown in the drawings, a regulating member is supported around the developing sleeve 28 by a developing case 27 with its tip close to the peripheral surface.

FIG. 2 shows an internal plan configuration of the developing device 12.
As can be seen from FIG. 2, in the developing case 27, a first conveying path 30 is provided on the bottom of the developing case 27 in parallel with the developing sleeve 28, on the side close to the developing sleeve 28, and on the far side. . Then, the first conveyance path 30 and the second conveyance path 31 are partitioned by a partition wall 34 leaving the communication paths 32 and 33 outside both ends, and the first conveyance path 30 is a first stirring and conveying member. The agitating and conveying screw 35 is accommodated in the second conveying path 31 with a second agitating and conveying screw 36 as a second agitating and conveying member, and the first agitating and conveying screw 35 and the second agitating and conveying screw 36 are rotatably arranged in parallel. To do. Two-component developer composed of toner and carrier is accommodated in the conveyance paths 30 and 31 for accommodating the agitating and conveying screws 35 and 36.

FIG. 3 shows a drive system of the developing device 12.
Reference numeral 37 in the figure denotes a drive motor provided in the image forming apparatus main body, and its rotation is transmitted to the developing sleeve 28, the first stirring / conveying screw 35, and the second stirring / conveying screw 36 of the developing device 12 through a gear train 38. Then, they are each rotated in the direction indicated by the arrow in the drawing, and are transmitted to other parts than the developing device 12 via the drive transmission belt 39.

  That is, at the time of development, the rotation of the drive motor 37 is transmitted via the gear train 38 to rotate the developing sleeve 28, the first stirring / conveying screw 35, and the second stirring / conveying screw 36. While the two-component developer is agitated and conveyed by the second agitating and conveying screw 36, it is passed through the communication paths 32 and 33 and circulated between the first conveying path 30 and the second conveying path 31, and part of the circulated developer. Is attached to the developing sleeve 28, the amount of the developer adhering to the developing sleeve 28 is regulated by a regulating member (not shown), and a predetermined amount of developer is guided to the developing area. In the developing area, the developing sleeve is passed through the opening 26. The toner is attached to the photoconductor 10 provided opposite to the photoconductor 28 to visualize the electrostatic latent image on the photoconductor 10.

  Incidentally, as shown in FIG. 1, a toner replenishing port 40 for replenishing replenished toner is opened in the developing case 27 on the upstream end portion of the second agitating and conveying screw 36. A guide member 43 that guides the replenished toner replenished from the toner replenishing port 40 to the input position 42 is provided. The guide member 43 is formed integrally with the developing case 27. Alternatively, it may be formed separately from the developing case 27 and supported by the developing case 27. In addition, a toner concentration detection sensor 44 that detects the toner concentration toward the first conveyance path 30 is attached to the developing case 27 below the first agitation conveyance screw 35.

  On the other hand, as shown in FIG. 2, paddle shapes 44 and 45 corresponding to the communication paths 32 and 33 are formed at the downstream end positions of the first stirring and conveying screw 35 and the second stirring and conveying screw 36, respectively. . In the paddle shapes 44 and 45, a plurality of blades whose blade surfaces are parallel to the screw axis are provided radially around the screw shaft, and the developer is sent through the communication paths 32 and 33 in a direction perpendicular to the screw shaft. The developer is transferred between the agitating / conveying screw 35 and the second agitating / conveying screw 36. That is, the developer is scraped off at one paddle shape 44 portion, and the developer is transferred from the first conveyance path 30 to the second conveyance path 31 through the communication path 32. Further, the developer is scraped by the other paddle-shaped 45 portion, and the developer is transferred from the second conveyance path 31 to the first conveyance path 30 through the communication path 33.

The replenishment toner charging position 42 described above is provided on the paddle-shaped portion 44 provided at the downstream end position of the first stirring and conveying screw 35 corresponding to the communication path 32.
FIG. 4 is an enlarged view around the downstream end portion of the first stirring and conveying screw 35.

FIG. 5 shows a toner replenishing device 50 for replenishing toner to the developing device 12 described above, as viewed obliquely from above.
In the toner replenishing device 50 shown in FIGS. 1 and 5, a bottle-like toner container 52 for storing new toner is mounted on a support 51 in a replaceable manner.

  The support 51 is provided with a toner conveying means 54 for sending new toner discharged from the toner container 52 toward the toner supply path 53. The toner conveying means 54 includes a plurality of toner conveying members 56 that rotate to discharge the toner from the discharge port 55 to the toner supply path 53. The toner supply path 53 is formed in the toner supply path forming member 57 and guides the toner discharged from the toner conveying means 54 to the toner supply port 40 of the developing device 12. The toner replenishment path forming member 57 is detachably attached to the developing device 12, and a filter 58 that allows air to pass but does not allow toner to pass is attached to the top.

  When the toner concentration in the developing case 27 decreases below a certain level as the toner is supplied to the photoreceptor 10 and the developer is consumed, the toner concentration detection sensor 44 detects the decrease in the toner concentration. The toner container 52 of the replenishing device 50 is rotated and the toner conveying means 54 is driven. As a result, new toner is sent from the toner container 52 to the toner conveying means 54, and the new toner is discharged from the discharge port 55 by the rotation of the toner conveying member 56. The discharged toner is dropped by its own weight to form a toner supply path. The toner 57 is put into the developing case 12 through the toner replenishing path 53 of the member 57, and a predetermined amount of toner is replenished in the developing case 27.

  The toner put in the developing case 12 is guided by the guide member 43 and falls onto the developer in the paddle-shaped portion 44 of the first agitating / conveying screw 35 at the loading position 42, thereby downstream of the first agitating / conveying screw 35. It is put into the paddle shape 44 portion at the position, and immediately stirred with the paddle shape 44 and mixed with the developer in the developing case 27. The developer is then conveyed to the upstream position of the second agitating and conveying screw 36 while being stirred so as to sink into the developer in the developing case 27, and the developer is agitated and conveyed by the first agitating and conveying screw 35 and the second agitating and conveying screw 36. However, it passes through the communication paths 32 and 33 and circulates between the first transport path 30 and the second transport path 31.

  A part of the circulating developer adheres to the developing sleeve 28. Similarly, the amount of the developer adhering to the developing sleeve 28 is regulated by a regulating member, and a predetermined amount of developer is led to the developing area, and the developing area Thus, the toner adheres to the photosensitive member 10 provided to face the developing sleeve 27 through the opening 26, and the electrostatic latent image on the photosensitive member 10 is visualized.

  Accordingly, in the illustrated example, the replenishment toner is sufficiently mixed with the developer in the developing case 27 and appropriately charged, and the phenomenon that the replenishing toner moves so as to slide on the developer surface in the developing case 27 is eliminated. Toner scattering can be reliably prevented. Further, the toner can be uniformly dispersed quickly after being replenished in the developer to eliminate uneven toner concentration, and the toner can be accurately replenished without the detection failure of the toner concentration in the developer. Further, the developing device 27 has an agitating and conveying force that is increased in the developing case 27 to accelerate the deterioration of the developer, or the stirring and conveying member is lengthened so that the replenished toner is mixed with the developer in the developing case 27. 12. As a result, the image forming apparatus can be enlarged, or a stirring member can be provided in the middle of conveyance to reduce the developer conveyance performance, so that the conventional problems in the case of replenishing toner can be solved.

  By the way, in the illustrated image forming apparatus, the internal pressure of the developing case 27 rises at the downstream position of the first agitating and conveying screw 35 due to the rotation of the photoconductor 10 and the rotation of the first agitating and conveying screw 35. This position is in the vicinity of the new toner input position 42, and there is a lot of floating toner. For this reason, there is a concern that the toner scatters from the opening 26 particularly when a large amount of new toner is introduced.

  Therefore, in the illustrated example, the toner supply path forming member 57 that supplies the supply toner to the developing device 12 is provided with a filter 58 that allows air to pass but not toner. As a result, the pressure in the developing case 27 is released from the toner replenishing path 53 to the outside through the filter 58, and the air pressure in the toner replenishing path 53 and the developing case 27 is prevented from rising above a certain level, thereby preventing toner scattering. The filter 58 may be bundled with a replacement toner container 52, and the filter 58 may be replaced at the same time when the toner container 52 is replaced. If it does in this way, exchange of filter 58 can be performed frequently and the pressure relief effect can be improved.

  If the toner replenishment path forming member 57 is detachable from the developing device 12 at this time, the filter 58 can be replaced by removing the toner replenishment path forming member 57 from the developing device 12 when the filter 58 is replaced. As an ease, it is possible to prevent an excessive increase in the pressure of the toner replenishment path forming member 57 and improve the toner scattering prevention effect of the uncharged toner.

  In the example described above, the developing case 27 is provided with the toner replenishing port 40 for replenishing the replenished toner and the guide member 43 for guiding the replenished toner replenished from the toner replenishing port 40 to the input position 42. The replenished toner replenished from the toner replenishing port 40 is guided to the input position 42 by a member provided in itself. However, for example, as shown in FIG. 6, a toner replenishment path forming member 57 for replenishing replenished toner is attached to the developing case 27, and its outlet 60 is placed in the developing case 27 and provided directly at the input position 42 of the developing device 12. You may do it. In this way, the configuration of the developing device 12 can be simplified.

FIG. 6 shows a schematic configuration of an internal mechanism of a main part in another monochrome electrophotographic image forming apparatus using a two-component developer. The reference numerals used for the corresponding parts in FIG. 1 are used as they are.
FIG. 7 is an enlarged view of the vicinity of the downstream end portion of the first stirring and conveying screw provided in another developing device.

  As described above, the downstream position of the first agitating and conveying screw 35 tends to increase the internal pressure, and since it is the new toner charging position 42, there is a lot of floating toner, especially when a large amount of new toner is charged. There is a risk of toner scattering from the opening 26. Therefore, as shown in the drawing, the first agitating and conveying screw 35 is extended downstream from the developing device 12 shown in FIG. Of course, the second agitating and conveying screw 36 is also extended to the upstream side accordingly, the communication path 32 is also moved, and the developing case 27 is lengthened. Thus, the paddle shape 44 is provided on the downstream side of the first agitating and conveying screw 35 from a position corresponding to the opening 26 provided in the developing case 27 and exposing the developing sleeve 28.

  In this way, the replenishment toner charging position 42 provided in the paddle-shaped portion 44 is moved away from the opening 26 of the developing case 27, so that the developing device 12 is enlarged, but the pressure of the first agitating and conveying screw 35 that tends to increase in pressure is increased. It is possible to prevent uncharged floating toner from scattering from the opening 26 to the outside of the developing case 27 at the downstream position.

FIG. 2 is a schematic configuration diagram of an internal mechanism of a main part in a monochrome electrophotographic image forming apparatus using a two-component developer. 2 is an internal plan view of a developing device provided in the image forming apparatus. FIG. It is a perspective view which shows the structure of the drive system of the developing device. FIG. 6 is an enlarged plan configuration diagram around a downstream end portion of a first stirring and conveying screw included in the developing device. FIG. 2 is a perspective view of a toner replenishing device provided in the image forming apparatus of FIG. 1. FIG. 6 is a schematic configuration diagram of an internal mechanism of a main part in another monochrome electrophotographic image forming apparatus using a two-component developer. FIG. 6 is an enlarged plan configuration diagram around a downstream end portion of a first agitation transport screw provided in another developing device. It is an internal schematic block diagram of the developing device of the conventional two-component developing system.

Explanation of symbols

10 Photoconductor (image carrier)
DESCRIPTION OF SYMBOLS 12 Developing device 24 Process cartridge 26 Opening of developing case 27 Developing case 28 Developing sleeve (developer carrier)
30 1st conveyance path 31 2nd conveyance path 32, 33 Communication path 34 Partition wall 35 1st stirring conveyance screw (1st stirring conveyance member)
36 2nd stirring conveyance screw (2nd stirring conveyance member)
40 Toner supply port 42 Supply toner supply position 43 Guide member 44 Paddle shape 57 Toner supply path forming member 58 Filter 60 Exit of toner supply path forming member

Claims (8)

A developer carrier that attaches toner to the image carrier and visualizes the latent image on the image carrier, and a first on the side close to the developer carrier that is provided in parallel with the developer carrier. A first conveying path and a second conveying path on the far side, a partition wall that partitions between the first conveying path and the second conveying path leaving a communication path outside both ends, and a first agitation stored in the first conveying path A developing member includes a conveying member and a second agitating / conveying member housed in the second conveying path, and the first agitating / conveying member and the second agitating / conveying member are rotated to deliver the first agitating and conveying member through the communication path. In a developing device that circulates between one transport path and the second transport path to stir and transport the developer,
A developing device, wherein a paddle shape is provided at a downstream position corresponding to the communication path of the first agitation transport member, and a replenishment toner charging position is provided at the paddle shape portion.   The developing device according to claim 1, wherein the developing case is provided with a toner replenishing port for replenishing replenished toner and a guide member for guiding the replenished toner replenished from the toner replenishing port to the loading position. .   The developing device according to claim 1, wherein an outlet of a toner supply path forming member that is attached to the developing case and supplies supply toner is provided at the input position.   The paddle shape is provided on the downstream side of the first agitating and conveying member from a position corresponding to an opening provided in the developing case and exposing the developer carrying member. 3. The developing device according to any one of 3 above.   A process cartridge comprising the developing device according to claim 1.   An image forming apparatus comprising the developing device according to claim 1.   The image forming apparatus according to claim 6, wherein a toner replenishment path forming member that replenishes replenishment toner to the developing device includes a filter that allows air to pass but does not allow toner to pass.   The image forming apparatus according to claim 7, wherein the toner supply path forming member is detachable from the developing device.

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