JP2008268783A - Developing device and image forming apparatus incorporating the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device capable of supplying a requested quantity of toner and a requested quantity of carrier with an arbitrary timing, capable of supplying developer to a developing container after preliminarily mixing and stirring the toner and carrier in order to stabilize charging characteristics, thereby carrying out high quality development of an electrostatic latent image. <P>SOLUTION: The developing device 50 includes: a toner supply container 62; a carrier supply container 63; an auxiliary stir container 64 separately receiving toner and carrier supplied from the toner supply container 62 and carrier supply container 63 respectively, and mixing and stirring them, thereby composing developer; and a developer container 51 receiving and storing the developer supplied from the auxiliary stirring container 64, and the supplying the developer to a photoreceptor drum 21 serving as an image carrier. This way makes it possible to arbitrarily set the quantities of toner and carrier conveyed to the developing container 51 and timing of conveying them. In addition, before the developer is supplied to the developing container 51, they can be mixed and stirred in the auxiliary stirring container 64 in advance. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a developing device applicable to an electrophotographic image forming apparatus typified by a copying machine or a printer, and more particularly to a developing device using a two-component developer. The present invention also relates to an image forming apparatus equipped with the developing device.

  In an electrophotographic image forming apparatus such as a copying machine or a printer, a photosensitive drum is widely used as an image carrier. A general image forming operation using the photosensitive drum is as follows. The surface of the photosensitive drum is uniformly charged with a predetermined potential by a charging device, and by irradiating the LED light or the like of the exposure device there, the potential is partially attenuated to form an electrostatic latent image of an original image. Is done. The electrostatic latent image is developed with a developing device to form a toner image. After the transfer of the toner image onto the paper, the remaining toner is cleaned on the surface of the photosensitive drum by the cleaning device, and the charge removal is performed by irradiating the neutralization light by the neutralization device in preparation for the next image forming operation. Is called.

  In the developing device that forms one of the cores of the image forming operation as described above, a predetermined amount of developer containing toner particles is always stored in the developing container, and is used for development. When it becomes less, it is replenished. At this time, generally, the developer is introduced into the developing container from the developer supply container disposed above the developing device by the action of gravity or a conveying member.

  Here, the development method includes a one-component method and a two-component method. The developer is composed only of toner particles in the one-component system, and is composed of toner particles and a carrier that is a carrier of the toner in the two-component system. In an image forming apparatus, a two-component development method is generally widely used.

  In the two-component development method, the amount of toner particles (hereinafter referred to as toner) in the developer is sequentially detected in the developing container, and new toner is replenished from the replenishing container in accordance with the consumption amount. However, since the carrier is used for a long period of time, there arises a problem that minute toner adheres to the surface and deteriorates. As a result, the development performance deteriorates, and there is a possibility that a high-quality image cannot be obtained.

  Therefore, in order to solve such a problem, a method of gradually replacing a deteriorated carrier with a new carrier has been proposed, and examples thereof can be seen in Patent Documents 1 and 2. The image forming apparatus described in Patent Document 1 includes a counting counter, and replenishes a carrier every time a predetermined number of sheets are printed. The image forming apparatus described in Patent Document 2 includes a toner consumption measuring unit, and replenishes a carrier according to the measurement result.

  However, the two-component developer has a further problem that the toner consumption speed and the progress of carrier deterioration are not constant. In addition, regarding the charging characteristics of the developer in the developer container, the newly replenished carrier has a large charge capacity with respect to the carrier existing in the developer container, so that it is easy to attract minute toner charged in the developer container, There is also a problem that deterioration tends to proceed.

Therefore, in order to solve these problems, a method for replenishing the developer container after mixing and stirring the toner and carrier of the two-component developer has been proposed, and an example thereof can be seen in Patent Document 3.
Japanese Patent Laid-Open No. 4-66984 (page 4, FIG. 1-2) JP-A-9-204105 (page 4, FIG. 3) JP 2001-209244 A (page 7-8, FIG. 5-8)

  In the image forming apparatus described in Patent Document 3, the developing device includes a carrier storage unit (carrier supply container) upstream of the toner storage unit (toner supply container), so that the carrier is temporarily transferred from the carrier storage unit into the toner storage unit. After the toner is supplied, the carrier and the toner are mixed and stirred, and the developer housing (developing container) is replenished as a developer. However, in this configuration, although the toner of the two-component developer and the carrier can be mixed and stirred in advance and supplied to the developing container, the carrier diffuses in the toner supplying container, and a desired amount of carrier is developed. The container may not be refilled. Thus, in order to supply a desired amount of carrier to the developing container, it is necessary to supply more toner than necessary. In addition, since the carrier replenishment time depends on the toner replenishment time, there is a high possibility that a deviation occurs in the replenishment timing. Therefore, the carrier cannot be supplied in time, which may adversely affect development.

  The present invention has been made in view of the above points. In a developing device using a two-component developer composed of toner particles and a carrier, a desired amount of toner and carrier are replenished at an arbitrary timing. Development that can perform high-quality development of an electrostatic latent image, and can supply the developer to the developing container after preliminary mixing and stirring to stabilize the charging characteristics. An object is to provide an apparatus. It is another object of the present invention to provide a high-performance image forming apparatus equipped with such a developing device.

  In order to solve the above problems, the present invention provides a toner replenishing container that contains toner, a carrier replenishing container that contains a carrier, toner replenishment from the toner replenishing container, and carrier replenishment from the carrier replenishing container. The auxiliary stirring container for stirring and mixing the developer and the developing container for receiving and supplying the developer from the auxiliary stirring container and supplying the developer to the image carrier are provided.

  In the present invention, the developing device is mounted on the image forming apparatus.

  According to the configuration of the present invention, in the developing device, the toner supply container that stores the toner, the carrier supply container that stores the carrier, the toner supply from the toner supply container, and the carrier supply from the carrier supply container are individually performed. Since it is provided with an auxiliary stirring container that receives, mixes and stirs, and mixes the developer, and a developer container that receives and stores the developer from the auxiliary stirring container and supplies the developer to the image carrier. It is possible to arbitrarily set the amount and timing of feeding the toner and carrier into the developing container. The developer can be mixed and stirred in advance in the auxiliary stirring container before being supplied to the developing container. Therefore, it is possible to provide a developing device capable of feeding a developer having sufficiently stable charging characteristics into the stirring chamber and capable of performing high-quality development of the electrostatic latent image.

  In the present invention, since the developing device is mounted on the image forming apparatus, a desired amount of toner and carrier can be replenished at an arbitrary timing, and a preliminary operation is performed to stabilize the charging characteristics. After mixing and stirring, the two-component developer can be supplied to the developing container, and a high-performance image forming apparatus capable of performing high-quality development of the electrostatic latent image can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  First, an image output operation of an image forming apparatus equipped with a developing device according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a left side view of a schematic vertical section showing a schematic structure of a printer as an example of an image forming apparatus. In FIG. 1, the right side is the front side of the printer, and the left side is the back side.

  As shown in FIG. 1, a paper feed cassette 3 that is a paper storage unit is disposed below the inside of the main body 2 of the printer 1. The paper P is stacked and accommodated inside the paper feed cassette 3. A paper feeding device 4 is disposed above the downstream portion of the paper feeding cassette 3 in the paper conveyance direction. The sheet feeding device 4 feeds the sheet P toward the upper right of the sheet feeding cassette 3 in FIG.

  A paper transport path 5, a registration roller 6, an image forming unit 20, and a transfer unit 30 are disposed downstream of the paper feed cassette 3 in the paper transport direction. The paper P sent out from the paper feed cassette 3 reaches the registration roller 6 through the paper transport path 5. The registration roller 6 feeds the paper P to the transfer unit 30 by correcting the oblique feeding of the paper P and timings the toner image formed by the image forming unit 20.

  Image data signals such as characters, graphics, and patterns from an external computer (not shown) are transmitted to the printer 1, and a laser controlled by the optical unit 7 provided above the image forming unit 20 based on the image data. Light L (dashed line in the figure) is irradiated. As a result, the image forming unit 20 forms an electrostatic latent image of the original image on the photosensitive drum 21 that is an image carrier, and the toner image is developed from the electrostatic latent image. The toner image is transferred to the paper P sent in synchronization by the registration roller 6 at a transfer nip portion formed by press contact between the photosensitive drum 21 and the transfer roller 31 of the transfer portion 30.

  A fixing unit 8, a sheet conveyance path 9, and a sheet discharge unit 10 are disposed downstream of the image forming unit 20 and the transfer unit 30 in the sheet conveyance direction. The paper P carrying the unfixed toner image in the transfer unit 30 is sent to the fixing unit 8 and the toner image is fixed by the heat roller. The paper P discharged from the fixing unit 8 is sent upward through the paper conveyance path 9 and is discharged outside the apparatus at the paper discharge unit 10 provided on the upper surface of the main body 2.

  Next, a detailed configuration around the image forming unit 20 of the printer 1 will be described with reference to FIG. 2 in addition to FIG. FIG. 2 is an enlarged left side view of the vertical section showing the periphery of the image forming unit.

  As shown in FIGS. 1 and 2, the image forming unit 20 includes a photosensitive drum 21 as an image carrier at the center thereof. In the vicinity of the photosensitive drum 21, a charging device 40, a developing device 50, and a cleaning device 80 are sequentially arranged along the rotation direction. The transfer unit 30 is provided between the developing device 50 and the cleaning device 80 along the rotation direction of the photosensitive drum 21.

  The photosensitive drum 21 extends in the paper width direction perpendicular to the paper transport direction in the printer 1, that is, the depth direction of the paper surface of FIG. 2, and is arranged with its axis direction horizontal. The photosensitive drum 21 is an inorganic photosensitive drum in which an amorphous silicon photosensitive layer, which is an inorganic photoconductive material, is provided on the outer side of a conductive roller-shaped substrate made of aluminum or the like by vacuum deposition or the like. The photosensitive drum 21 is rotated by a driving device (not shown) so that the peripheral speed thereof is substantially the same as the paper conveyance speed.

  The charging device 40 is a scorotron charging device using a corona discharge charger. Similarly, a corotron charging device using a corona discharge charger or a contact charging device using a roller or a brush may be used. By this charging device 40, the surface of the photosensitive drum 21 is uniformly charged with a predetermined polarity and potential.

  The developing device 50 includes a developing roller 52 inside the developing container 51. The developing roller 52 is a magnetic jumping developing method, and is provided in the vicinity of the photosensitive drum 21 in parallel with the axis. A bias having the same polarity as the charging polarity of the photosensitive drum 21 is applied to the developing roller 52. The developing roller 52 charges the toner in the developer and moves it to the electrostatic latent image on the surface of the photosensitive drum 21 to develop the electrostatic latent image. The developer is a two-component developer composed of toner particles (toner) and a carrier that is a carrier of the toner particles. The detailed configuration of the developing device 50 will be described later.

  The transfer unit 30 is provided with a transfer roller 31 as a transfer member. The transfer roller 31 is in pressure contact with the photosensitive drum 21 to form a transfer nip portion through which the paper P is inserted. The transfer roller 31 is rotated by a driving device (not shown) so that the peripheral speed thereof is the same as the peripheral speed of the photosensitive drum 21. Further, a transfer bias having a polarity different from the charging polarity of the photosensitive drum 21 and the toner is applied to the transfer roller 31 as necessary. In FIG. 2, the conveyance path of the paper P is drawn with a two-dot chain line.

  As shown in FIG. 2, the cleaning device 80 is arranged further downstream of the transfer nip portion along the rotation direction of the photosensitive drum 21. The cleaning device 80 includes a cleaning roller 82 and a cleaning blade 83 in the housing 81.

  The cleaning roller 82 and the cleaning blade 83 are urged by an elastic member such as a spring (not shown) and are pressed against the photosensitive drum 21. The cleaning roller 82 and the cleaning blade 83 extend in the axial direction of the photosensitive drum 21 and have substantially the same axial length as the photosensitive drum 21.

  In order to perform cleaning efficiently, the cleaning roller 82 is connected to the photosensitive drum 21 so that the peripheral speed of the cleaning roller 82 is about 15 to 20% faster than the peripheral speed of the photosensitive drum 21 by a driving device (not shown). The surface at the contact point is rotated in such a direction as to move in the same direction as the surface of the photosensitive drum 21. The cleaning device 80 removes deposits such as toner remaining on the surface of the photosensitive drum 21 after the toner image on the surface of the photosensitive drum 21 is transferred to the paper P by the cleaning roller 82 and the cleaning blade 83. To clean. The toner removed from the surface of the photosensitive drum 21 is once collected in the housing 81 and discharged to a waste toner collecting container (not shown).

  Next, the detailed configuration of the developing device 50 will be described with reference to FIG. 3 in addition to FIGS. 1 and 2. FIG. 3 is a horizontal cross-sectional top view of the developing device taken along line III-III in FIG. 2, in which four types of containers, a developing container, an auxiliary stirring container, a toner supply container, and a carrier supply container, are arranged in a horizontal direction. It is a thing.

  The developing device 50 includes a developing container 51 as shown in FIGS. 2 and 3. As described above, the developer container 51 contains a two-component developer composed of toner particles and a carrier as described above. The developing container 51 has an elongated shape in the axial direction of the photosensitive drum 21 and is disposed with its longitudinal direction horizontal. A main portion in the developing container 51 is provided with a stirring chamber 53 for transporting the developer while stirring. The inside of the stirring chamber 53 is partitioned into two left and right sections in FIG. 2 by a partition wall 54 extending in the longitudinal direction of the developing container 51. The right compartment is the first chamber 55, and the left compartment is the second chamber 56.

  The second chamber 56 includes an opening 57 at a location adjacent to the photosensitive drum 21. A developing roller 52 that is a developer carrier is disposed in the opening portion 57. One side of the developing roller 52 is located inside the second chamber 56, and the other side is exposed to the outside of the second chamber 56 and faces the photosensitive drum 21 that is an image carrier. The developing roller 52 is rotated counterclockwise in FIG. 2 by a driving means (not shown).

  A regulating plate 58 is provided on the downstream side in the rotational direction from the position inside the second chamber 56 of the developing roller 52, that is, above the developing roller 52 in FIG. 2. The regulating plate 58 is disposed with a gap having a predetermined width between its lower end and the surface of the developing roller 52.

  On the other hand, the first chamber 55 is provided with a toner sensor 59 as developer detection means on a side surface extending in the longitudinal direction. The toner sensor 59 can detect the amount of developer (toner) in the stirring chamber 53.

  Further, in the stirring chamber 53, the partition wall 54 is not provided over the entire region between both ends in the longitudinal direction, but the first chamber 55 and the first chamber 55 are separated by a clearance provided at both ends of the partition wall 54 and a clearance above the partition wall 54. The two chambers 56 communicate with each other. The first chamber 55 and the second chamber 56 are respectively provided with a first agitating / conveying member 60 and a second agitating / conveying member 61 for agitating and conveying the developer with their axes substantially horizontal. When these agitating and conveying members have a screw shape or a spiral shape and are rotated, the agitating and conveying members convey the developer in the agitating chamber 53 in a clockwise direction as viewed from above, as indicated by white arrows in FIG. Thus, the developer is conveyed and circulated in the stirring chamber 53 while being stirred between the first chamber 55 and the second chamber 56.

  As shown in FIG. 2, the developing device 50 includes a toner supply container 62, a carrier supply container 63, and an auxiliary stirring container 64 above the developing container 51. Each of these three types of containers has a shape that extends long in the paper width direction. An auxiliary stirring container 64 is disposed immediately above the developing container 51, and a toner replenishing container 62 and a carrier replenishing container 63 are arranged in the vertical direction above the auxiliary stirring container 64.

  The toner supply container 62 and the carrier supply container 63 are arranged side by side in the front-rear direction as shown in FIG. The length of the toner supply container 62 and the carrier supply container 63 in the front-rear direction in which two types of supply containers are arranged, that is, the length in the paper width direction, is substantially the same as the length of the developing container 51 in the paper width direction. The toner supply container 62 has a substantially larger volume than the carrier supply container 63.

  The toner replenishing container 62 includes an agitating blade 65 and an agitating / conveying member 66 therein, and contains toner.

  The stirring blade 65 is provided with a substantially horizontal axis, and is formed in a sheet shape extending radially outward from the shaft portion. When the agitating blade 65 rotates about the axis, the agitating blade 65 contacts the inner wall of the lower portion of the toner supply container 62 and agitates the toner while rotating so as to rub. The stirring blade 65 rotates in the clockwise direction in FIG. 2, and a stirring and conveying member 66 is disposed at a lower portion on the downstream side in the rotation direction that is released from contact with the inner wall of the toner supply container 62. In FIG. 2, the stirring blade 65 and the stirring and conveying member 66 of the toner replenishing container 62 are not shown, but these are illustrated in FIG. It is arranged in the same manner as 69.

  The agitating / conveying member 66 has the same screw shape or spiral shape as the first agitating / conveying member 60 and the second agitating / conveying member 61 of the developing container 51, and is provided with the axis substantially horizontal. As shown in FIG. 3, a toner replenishing port 67 is provided at the frontmost bottom portion where the stirring and conveying member 66 is disposed. When the agitating and conveying member 66 is rotated, the toner is conveyed while being agitated toward the toner supply port 67, that is, from the rear to the front.

  The toner supply port 67 communicates with an auxiliary stirring container 64 disposed below the toner supply port 67. The toner is replenished by freely dropping into the auxiliary stirring container 64 from the position indicated by a two-dot chain line arrow extending from the toner replenishing port 67 shown in FIG.

  Similar to the toner supply container 62, the carrier supply container 63 includes a stirring blade 68 and a stirring / conveying member 69 and contains a carrier.

  The stirring blade 68 has a sheet shape extending outward in the radial direction, and the stirring and conveying member 69 has a screw shape or a spiral shape, both of which are provided with axes substantially parallel to each other. As shown in FIG. 3, a carrier replenishing port 70 is provided at the position of the rearmost bottom portion where the stirring and conveying member 69 is disposed. When the agitating and conveying member 69 is rotated, the carrier is conveyed while being agitated toward the carrier replenishment port 70, that is, from the front to the rear.

  The carrier replenishment port 70 communicates with an auxiliary stirring container 64 disposed below the carrier replenishment port 70. The carrier is replenished by freely dropping into the auxiliary stirring vessel 64 from the position indicated by the two-dot chain line arrow extending from the carrier replenishing port 70 shown in FIG.

  The auxiliary stirring vessel 64 includes only the stirring and conveying member 71 therein. The agitating / conveying member 71 has a screw shape or a spiral shape as in the above-described agitating / conveying member.

  The auxiliary stirring container 64 has an elongated shape in the paper width direction, the front end thereof is a location corresponding to the carrier supply port 70, and the rear end is located at the substantially central portion of the developing container 51 in the paper width direction. The auxiliary agitation container 64 individually receives and mixes toner supply from the toner supply port 67 of the toner supply container 62 disposed above, and carrier supply from the carrier supply port 70 of the carrier supply container 63. Stir to mix the developer.

  A developer replenishing port 72 is provided at the bottom end of the auxiliary stirring container 64. When the agitating and conveying member 71 is rotated, the developer is conveyed while being agitated toward the developer supply port 72, that is, from the front to the rear.

  The developer supply port 72 communicates with the developer container 51 disposed below the developer supply port 72. The developer is replenished from the location indicated by the two-dot chain line arrow extending from the developer replenishing port 72 shown in FIG. 3 into the first chamber 55 of the agitating chamber 53 of the developing container 51.

  The agitating blades and agitating / conveying members provided in the toner replenishing container 62, the carrier replenishing container 63, and the auxiliary agitating container 64 are each driven by an independent driving device (not shown).

  The developing device 50 configured as described above operates as follows.

  During normal printing, the drive unit corresponding to the toner replenishing container 62 and the auxiliary stirring container 64 operates in response to information from the toner sensor 59 of the developing container 51, and each stirring and conveying member rotates to return to the developing container 51. Toner is supplied. Thereafter, the driving device for the toner replenishing container 62 is stopped, and the driving device for the auxiliary stirring container 64 is stopped at the timing when all the toner in the auxiliary stirring container 64 is supplied to the developing container 51.

  The carrier supply container 63 is not driven until a predetermined time has elapsed after the driving of the developing device 50 is started. When the driving time of the developing device 50 has passed 5 hours, the carrier replenishing container 63 replenishes the carrier by about 1 g every 30 minutes. The replenishment of the carrier is performed when it is necessary to replenish the toner according to the information from the toner sensor 59 after the developing device 50 has been driven for 5 hours.

  In this case, first, all the driving devices of the toner replenishing container 62, the carrier replenishing container 63, and the auxiliary stirring container 64 are operated to replenish toner, carrier, and developer. Thereafter, when the carrier supply reaches a predetermined amount, the drive device for the carrier supply container 63 stops. Then, after the replenished carrier passes through the portion corresponding to the toner replenishing port 67 in the auxiliary stirring container 64, the driving device of the toner replenishing container 62 stops. Further, when the developer in the auxiliary stirring container 64 is completely replenished to the developing container 51, the driving device for the auxiliary stirring container 64 is stopped.

  Next, the effect of differences in toner and carrier replenishment methods when developing using the developing device 50 on changes in image density, fog, and spent rate will be described with reference to FIG. FIG. 4 is a table showing the effect of differences in toner and carrier replenishment methods on changes in image density, fog, and spent rate. As an evaluation method, after printing a predetermined number of sheets from 10,000 sheets to 80,000 sheets, the image density and fog density of the printed image and the spent ratio of the developer in the developing container 51 were measured.

  Here, the developer is composed of the following toner and carrier. As the toner, 92 parts of styrene acrylic resin, 5 parts of carbon black, and 3 parts of CCA were mixed and pulverized to an average particle size of 8 μm. On the other hand, the carrier is a ferrite carrier having an average particle size of 80 μm.

  For the image density, a reflection densitometer (TC-6D manufactured by Tokyo Denshoku Co., Ltd.) was used, and the density of the black solid portion of the printed image was measured.

  Further, “fogging” means a phenomenon in which the toner adheres to a non-image portion that originally becomes white due to a developing operation, and the density increases. The blackening density is called “fogging density”. For the fog density, the reflection densitometer TC-6D was used, and the density of the blank portion of the printed image was measured.

  “Spent” means a phenomenon in which toner particles adhere to the surface of carrier particles. The spent rate was measured as follows. First, after a predetermined number of prints having a toner occupation ratio of 4% on the paper surface were printed as shown in FIG. 4, the developer was passed through a 400-mesh sieve and sucked by a blower from below to separate the toner and the carrier. Then, 5 g of the carrier remaining on the sieve was transferred to a container, toluene was added, and the toner adhering to the surface of the carrier particles was dissolved by spent. Thereafter, toluene was discarded while attracting the carrier with a magnet from below the container. The dissolution of the toner on the surface of the carrier particles with toluene was repeated several times until the toluene became colorless, and then the toluene attached to the carrier was evaporated in an oven. The difference in weight between the carrier thus obtained and the carrier (5 g) initially placed in the container is the amount of toner adhering to the surface of the carrier particles due to spent. The “spent rate” shown in FIG. 4 represents the toner amount (mg) attached to 1 g of the carrier.

  In FIG. 4, in Example 1, about 1 g of the carrier is supplied together with the toner every 30 minutes after the driving time of the developing device 50 has passed 5 hours. According to this, even when printing 800,000 sheets, the image density was good and the spent rate was satisfactory.

  In Example 2, after the driving time of the developing device 50 has passed 5 hours, about 1 g of the carrier is supplied together with the toner every 15 minutes. In this case, as in Example 1, even when printing 800,000 sheets, the image density was good and the spent rate was satisfactory.

  In Example 3, about 1 g of the carrier is supplied together with the toner every 30 minutes from the beginning of printing. In this case as well, as in Examples 1 and 2, even when 800,000,000 sheets were printed, the image density was good and the spent rate was satisfactory.

  In Comparative Example 1, no carrier was replenished. In this case, as the number of printed sheets increased, the spent rate increased significantly, fogging became noticeable when 60000 sheets were printed, and toner scattering occurred, so the development operation was stopped.

  In Comparative Example 2, only about 1 g of the carrier was replenished every 30 minutes after the conditions of Example 1, that is, the driving time of the developing device 50 passed 5 hours, and the toner was not replenished. In this case, although spent slowly, the fog density greatly increased after printing 80000 sheets.

  In this way, the developing device 50 includes a toner supply container 62 for storing toner, a carrier supply container 63 for storing carriers, toner supply from the toner supply container 62, and carrier supply from the carrier supply container 63. Auxiliary agitation container 64 for individually receiving, mixing and agitating, and mixing the developer, receiving and supplying the developer from the auxiliary agitation container 64, and supplying the developer to the photosensitive drum 21 as an image carrier. Since the developing container 51 is provided, it is possible to arbitrarily set the amount and timing of feeding the toner or carrier into the developing container 51. The developer can be mixed and stirred in advance in the auxiliary stirring container 64 before the developer container 51 is replenished. Accordingly, it is possible to provide a developing device 50 that can feed a developer having sufficiently stable charging characteristics into the stirring chamber 53 and can perform high-quality development of an electrostatic latent image.

  In the present invention, since the developing device 50 is mounted on the printer 1 as an image forming apparatus, a desired amount of toner and carrier can be replenished at an arbitrary timing, and a preliminary operation is performed to stabilize the charging characteristics. The two-component developer can be replenished to the developing container 51 after carrying out typical mixing and stirring, and a high-performance printer 1 capable of performing high-quality development of an electrostatic latent image can be obtained. .

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  For example, in the embodiment of the present invention, the printer 1 which is an image forming apparatus equipped with the developing device 50 has been described by taking a monochrome printing model as an example, but the type of the image forming apparatus is limited to this. Instead, a model for transferring a toner image to a sheet using an intermediate transfer member or a color printing model using a plurality of color toners may be used.

  The present invention can be used in all developing devices applicable to image forming apparatuses.

1 is a left side view of a schematic vertical section of a printer equipped with a developing device according to an embodiment of the present invention. FIG. 2 is an enlarged left side view of a vertical section showing the periphery of the image forming unit in FIG. 1. FIG. 3 is a horizontal sectional top view of the developing device taken along line III-III in FIG. 2, in which four types of containers are drawn side by side in the horizontal direction. 6 is a table showing the effect of differences in toner and carrier replenishment methods on changes in image density, fog, and spent rate.

Explanation of symbols

1 Printer (image forming device)
DESCRIPTION OF SYMBOLS 20 Image formation part 21 Photoconductor drum 50 Developing device 51 Developing container 52 Developing roller 53 Stirring chamber 54 Partition 55 First chamber 56 Second chamber 59 Toner sensor 62 Toner replenishing container 63 Carrier replenishing container 64 Auxiliary stirring container 67 Toner replenishing port 70 Carrier supply port 72 Developer supply port

Claims (2)

  Toner supply container for storing toner, carrier supply container for storing carrier, toner supply from toner supply container, and carrier supply from carrier supply container are individually received, mixed, stirred, and mixed with developer. A developing device comprising: an auxiliary stirring container; and a developing container that receives and stores developer from the auxiliary stirring container and supplies the developer to the image carrier.   An image forming apparatus comprising the developing device according to claim 1.

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