JP2004151542A - Developing apparatus for image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent toner from staying and becoming solid with an easy and inexpensive constitution in order to solve failures such as irregularities in an image due to the shortage of toner caused by the following troubles; the toner stays in a toner inlet and in a gap between a stirring/carrying means and the inner wall of a developing apparatus and the toner becomes solid and the toner supply to the stirring/carrying means is interrupted. <P>SOLUTION: The developing apparatus is provided with a guiding member constituted so that it widens toward the stirring/carrying means side, and also, it is formed to a shape along the outer rotating edge of the stirring/carrying means and surrounding the toner inlet and it can guide the toner from the toner inlet to the stirring/carrying means and prevent the toner from staying in a gap between the stirring/carrying means and the developing apparatus inner wall. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a developing device in an image forming apparatus such as a copying machine, a printer, a facsimile, and a multifunction machine using the electrophotographic method, and in particular, conveys agitated developer to a developing roller for developing a latent image on a photoconductor. The present invention relates to a developing device in an image forming apparatus having a unit for performing toner mixing and a toner container such as a toner container for supplying toner to a conveying unit.
[0002]
[Prior art]
In an image forming apparatus using an electrophotographic method, a developing roller carrying toner is used to develop a latent image formed on a photoconductor, and a charged toner is supplied to the developing roller. There is a type that uses a stirring and conveying member for the agent. Further, since toner is consumed by developing the latent image on the photoconductor in this manner, for example, Patent Documents 1 and 2 which are inventions of a developing device in an image forming apparatus using a two-component developer are disclosed in There is disclosed an apparatus in which a sensor for detecting the toner concentration is provided in the developing device, and when the toner decreases and the toner concentration decreases, the toner is supplied from a detachable toner container to the developing device. Also, instead of supplying the toner only when the toner concentration is reduced, a mechanism for reciprocating the toner cartridge for supplying the toner is provided to move the toner to the vicinity of the discharge port provided at one end of the toner cartridge. Patent Documents 3 and 4 disclose devices in which the toner is allowed to freely fall into a developing device.
[0003]
However, the devices described in Patent Documents 1 and 2 require a toner density detection sensor and a device including a drive source and a control circuit for supplying toner when the toner density decreases, and are complicated. It has to be expensive. Further, the devices described in Patent Documents 3 and 4 do not require a sensor or a driving source for supplying toner, but require a mechanism for reciprocating the toner cartridge. Vibration is transmitted to the image forming apparatus itself by the movement mechanism, and may affect other mechanisms to cause image deterioration.
[0004]
For this reason, the applicant of the present application discloses in Patent Document 5 that a driving force of a toner conveying member in a toner container is obtained from a driving source for driving a developing roller or the like in a developing device, and the conveying member conveys the toner to one end of the developing device. A developing device has been proposed in which the toner can be replenished without using a special driving source, a control circuit, a reciprocating mechanism, etc., by agitating the toner from the toner receiving port provided in the printer and dropping the toner onto a conveying member. Further, in Patent Document 5, when the toner agitation on the developing device side and the amount of toner conveyed by the conveying member are uniform, even if the toner is supplied from the toner receiving port, the toner is conveyed immediately to make an empty space. Since toner is replenished and the supply becomes excessive, causing toner clogging, agitation on the downstream side of the position where the toner falls in the developing device, and the conveyance capability of the conveyance member are locally reduced to prevent toner clogging. He also suggested that
[0005]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2000-112220 [Patent Document 2]
Japanese Patent Application Laid-Open No. 2000-112221 [Patent Document 3]
Japanese Patent Application Laid-Open No. 2002-72645 [Patent Document 4]
JP 2002-99136 A [Patent Document 5]
JP 2001-235933 A
[Problems to be solved by the invention]
However, in the developing device proposed in Patent Document 5, for example, when the maximum size of the recording medium handled by the image forming apparatus is about A4, the distance between the outer edge of the stirring and conveying member and the inner wall of the developing apparatus is about 1 mm. Thus, toner can be supplied without causing toner clogging. However, in the case of an image forming apparatus that handles a large-sized recording medium such as A3, it is expected that the bending of the stirring / conveying member is increased. It is necessary to increase this interval to about 2 mm. However, if the distance between the outer edge of the agitating and conveying member and the inner wall of the developing device is increased, the toner supplied between the inner wall and the agitating and conveying member is clogged and hardened. As a result, the stirring and supply to the conveying member may be hindered, and the amount of toner may be insufficient, thereby causing problems such as image unevenness.
[0007]
In view of the above circumstances, an object of the present invention is to provide a developing device in an image forming apparatus that has a simple and inexpensive configuration and prevents toner clogging near a toner receiving port in the developing device.
[0008]
[Means for Solving the Problems]
Therefore, in the present invention, as described in claim 1,
Stirring and conveying means for supplying the developer to the developing roller for developing the latent image formed on the photoreceptor while stirring, and detachable toner provided above the stirring and conveying means for supplying toner to the developing device A developing device in the image forming apparatus having a toner receiving port for receiving toner from the storage means;
A guide member is provided to surround the toner receiving port, guide the toner from the toner receiving port to the stirring and conveying means, and prevent the toner from staying between the stirring and conveying means and the inner wall of the developing device. I do.
[0009]
In this way, by providing a simple and inexpensive member, such as a guide member that surrounds the toner receiving port of the developing device and guides the toner to the agitating and conveying unit, the outer edge of the agitating and conveying unit and the inner wall of the developing device are connected. This prevents or reduces the phenomenon that the toner does not enter into the gap, and thus the replenished toner stagnates or clogs and does not fall off in the portion, so that problems such as image unevenness due to agitation and obstruction of toner supply to the conveyance unit can be prevented. .
[0010]
And the invention described in claim 2 is:
The stirring and conveying means corresponding to the guide member installation site is provided with a scraper for scraping the toner accumulated in the guide member.
[0011]
In this way, by providing the scraper in the stirring and conveying means, even if the toner accumulates in the guide member, it becomes possible to scrape out the toner, and the toner flows between the outer edge of the stirring and conveying means and the inner wall of the developing device. In combination with the ability to prevent stagnation, it is possible to prevent problems such as image unevenness caused by impeding toner supply to the stirring and conveying means.
[0012]
The invention described in claim 3 is:
The guide member is formed so as to diverge toward the stirring and conveying means.
[0013]
By configuring the guide member in this manner, even if the toner is clogged in the vicinity of the toner receiving port, the stirring of the guide member and the conveying means side are widened, so that the weight of the toner or the pressure at which the toner is discharged from the toner container is changed. This clogging is broken, and problems such as image unevenness due to agitation and inhibition of toner supply to the conveying means can be prevented.
[0014]
And the invention described in claim 4 is:
The stirring / transporting means side of the guide member is formed along a rotating outer edge of the stirring / transporting means.
[0015]
By configuring the guide member in this manner, the gap between the guide member and the outer edge of the stirring and conveying means is substantially uniform, and the supplied toner is separated from the gap between the guide member and the stirring and conveying means by the inner wall of the developing device. To prevent the toner from stagnating or clogging between the outer edge of the conveying means and the inner wall of the developing device. Can be prevented.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be illustratively described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention to them unless otherwise specified, and are merely mere descriptions. This is just an example.
[0017]
FIG. 1 is a schematic sectional view showing an embodiment of a developing device in the image forming apparatus of the present invention, and FIG. 2 is an embodiment of a toner guide member provided in a toner receiving port of the developing device in the image forming apparatus according to the present invention. FIG. 3 is a perspective view, FIG. 3 is a plan view of one embodiment of a developing device main body in the image forming apparatus according to the present invention, and FIG. 4 is one embodiment of a stirring and conveying means constituting the developing device in the image forming apparatus according to the present invention. It is a perspective view.
[0018]
In the figure, reference numeral 1 denotes a developing device, 2 denotes a developing device main body according to the present invention, 3 denotes a toner container serving as a toner storing means which stores toner and is detachably attached to the developing device main body 2, and 4 denotes a developing device main body. A guide member that surrounds the toner receiving port 5 and guides the toner supplied from the toner container 3 to the agitating and transporting unit 6, a stirring unit 7 on the developing roller 8 side, and a transporting unit 8. , A developing roller for carrying a toner layer on the surface by a conventionally known method to develop a latent image formed on the surface of the photoreceptor, 9 is a housing of a toner container, and 10 is a toner roller accommodated in the toner container 3. The transport means 10 and 11 are provided to the developing device main body 2 when the toner container 3 is mounted on the developing device main body 2. Coupled with a driving source and a gear for driving a la 8 are driven.
[0019]
Reference numeral 30 denotes a developing chamber of the developing device main body 2, and 31 denotes an upright wall which separates a toner path in the developing chamber 2 and a conveying path of the conveying means 6, 7. Then, the toner sent by the stirring and conveying means 6 and 7 circulates through the gaps provided at both ends of the upright wall 31. Reference numeral 32 denotes a driving source for driving the developing roller 8 and stirring and conveying means 6, 7; 33, a gear for stirring the driving force from the driving source 32 to the conveying means 6, 7; 34, a stirring and conveying means 6; , 7 indicate the rotation direction, 35 and 36 indicate a spiral blade member of the stirring and conveying means, 37 indicates an arrow indicating the conveying direction of the toner, 38 indicates a scraper, 39 and 40 indicate the stirring, and the toner receiving in the conveying means 6 In the portion where the transfer capability of the blade member is reduced on the downstream side of the port 5, the reduction in the transfer capability is achieved by reducing the pitch and the outer diameter of the spiral blade member 36, setting only the pitch, or setting only the outer diameter smaller. This is performed by forming a notch in the spiral blade member 36 or omitting the spiral blade.
[0020]
As is clear from FIGS. 1 and 2, the guide member 4 has a shape in which the bottom 20 of the guide member 4 is agitated and spaced along the outer edge of the conveying means 6 by, for example, about 1 to 2 mm. The side of the agitating / transporting means 6 is divergently formed, for example, with a taper of 50 to 70 degrees, preferably about 60 degrees. Further, as shown in FIG. 3 in which the structure above the agitating / transporting means 6 and 7 in the developing device main body 2 is removed, an upright wall 31 is provided in the developing chamber 30, and on both sides of the upright wall 31. Further, stirring and transporting means 6 and 7 having spiral blade members 35 and 36 whose spiral directions are opposite to each other are provided. The stirring and conveying means 6 and 7 are driven in the same rotational direction indicated by an arrow 34 by a gear 33 transmitting a driving force from a driving source 32 of the developing roll 8 and the like. The toner supplied from the toner receiving port shown by the arrow is conveyed in the direction of arrow 37 on both sides of the upright wall 31 while being stirred by the blade members 35 and 36. As shown in FIG. 4, the agitating and conveying means 6 having the spiral blade member 36 is a portion corresponding to the toner receiving port 5 in the developing device main body 2, more specifically, a toner receiving port in FIG. A scraper 38 is attached to a blade member of the stirring / transporting means 6 corresponding to about 1/4 from the upstream side of the toner supply 5 and a part of the toner receiving port 5 downstream from the downstream in the toner transport direction in the toner transporting direction. The shape of the blade members 39, 40 of the means is different from that of the other parts so as to locally reduce the toner conveying capacity. Note that the toner receiving port 5 is provided above the position of one third from the end of the stirring / transporting means 6 and has a length of about １ ／ of the entire length of the stirring / transporting means 6. Since the toner is hardly affected by the bending of the stirring / conveying member 6, there is an effect that the toner does not leak between the toner and the inner wall of the developing device.
[0021]
When the toner container 3 is mounted on the developing device main body 2 in the developing device 1 according to the present invention configured as described above, the conveying units 10 and 11 are driven by gears or the like (not shown), and the toner in the toner container is It is sent to the conveying means 11 side. On the other hand, on the side of the developing device main body 2, the driving force from the driving source 32 is transmitted to the conveying means 6, 7 by the gear 33 or the like, and the developer is conveyed while being stirred in the developing chamber 30 to the developing roller 8. Sent. Then, the toner is carried by the developing roller 8, and the latent image on the photoconductor (not shown) is developed. When the toner is developed in the developing chamber 30 and the toner in the developing chamber 30 is reduced and the toner is vacated between the agitating / transporting unit 6 and the supply port of the toner container 3, the conveying unit is moved inside the toner container 3. The toner sent to the side 11 is dropped from the toner receiving port 5 of the developing device main body 2 via the guide member 4 onto the stirring / transporting means 6.
[0022]
The toner is conveyed in the direction of the arrow 37 while being agitated by the agitating and conveying means 6, and some of the blade members 39 and 40 downstream of the toner receiving port 5 of the agitating and conveying means 6 are Since the toner carrying capacity is reduced compared to the other blade members, the supplied toner stays at the blade members 39 and 40 and all the supplied toner is uniformly sent to the downstream side. There is no. Therefore, since there is no space between the agitating / transporting means 6 and the toner receiving port 5, the dropping of the toner from the toner container 3 is stopped, and the toner is not excessively supplied to the developing chamber 31 side. Further, the toner supplied from the toner container 3 is guided from the toner receiving port 5 of the developing device main body 2 to the stirring and conveying means 6 by the guide member 4, and the stirring of the guide member 4 and the conveying means 6 side diverge. Therefore, even if the toner is hardened near the toner receiving port 5 due to the own weight of the toner itself and the pressure for sending out the toner from the toner container, even if the toner is hardened in the vicinity of the toner receiving opening 5, This mass is broken. Further, even if the solidification is not broken by the weight of the toner itself and the pressure of sending out the toner from the toner container, a scraper 38 is provided in the vicinity of the toner receiving port 5 of the stirring and conveying means 6. As a result, the lump of toner can be reliably broken.
[0023]
Further, since the stirring / transporting means 6 side 20 of the guide member 4 is formed along the rotating outer edge of the stirring / transporting means 6, the inner wall of the developing device main body 2 is formed between the guide member 4 and the stirring / transporting means 6. It is possible to minimize the leakage of the toner into the gap, and to prevent the toner from staying or clogging in that portion. Therefore, the toner supplied between the inner wall of the developing device main body 2 and the agitating / transporting means 6 hardens as in the conventional apparatus, and does not fall down, and the agitation and supply to the transporting means 6 are hindered. It is possible to prevent a shortage and a problem such as image unevenness.
[0024]
[Example]
In an image forming apparatus having an OPC photosensitive member having a diameter of 30 mm and performing magnetic jumping development, the linear speed ratio between the photosensitive member and the developing roller is 1.4, and the linear speed ratio between the developing roller and the agitating / conveying means 7 is 0. .48, the linear velocity ratio of the stirring and conveying means 6 and 7 was 1.0, the guide member 4 was 9 × 43 mm in inner size, the divergent taper angle was 60 °, the distance between the guide member 4 and the stirring and conveying means 6 Is set to 1 mm, toner clogging occurs, but the toner is very thin, and collapses due to the weight of the toner itself and the pressure of toner from the toner container 3, and the clogged toner is destroyed by the scraper 38, thereby hindering toner supply. There was no.
[0025]
【The invention's effect】
According to the first aspect of the present invention, as described above, a simple and inexpensive member such as a guide member that surrounds the toner receiving port of the developing device and guides the toner to the conveying means is provided. Therefore, it is possible to prevent or reduce the phenomenon that the toner does not enter between the outer edge portion of the conveying means and the inner wall of the developing device, and thus the replenished toner stays or is clogged and does not drop in that portion. This prevents problems such as image unevenness due to toner supply obstruction.
[0026]
According to the second aspect of the present invention, by providing a scraper for the stirring and conveying means, even if toner is accumulated in the guide member, it is possible to scrape the toner, and the outer edge of the stirring and conveying means and the developing device In addition to preventing the toner from staying with the inner wall of the image forming apparatus, problems such as image unevenness due to agitation and obstruction of toner supply to the conveying means can be prevented.
[0027]
According to the third aspect of the present invention, since the member for guiding the toner is formed to be divergent on the side of the stirring and conveying means, even if the toner is clogged in the vicinity of the toner receiving port, the stirring and conveying of the guide member is performed. Since the device side is widened, the clogging is broken by the weight of the toner or the pressure of the toner fed from the toner container, and problems such as image irregularity due to agitation and obstruction of the toner supply to the conveying device can be prevented.
[0028]
According to the fourth aspect of the present invention, the agitating and conveying means side of the member for guiding the toner is formed along the rotation outer edge of the agitating and conveying means. Between the guide member and the agitating / transporting means, it is possible to minimize leakage of the supplied toner to the inner wall of the developing device. The toner can be prevented from staying or clogging between the outer edge of the means and the inner wall of the developing device, and problems such as image unevenness due to obstruction of toner supply can be prevented.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view showing an embodiment of a developing device in an image forming apparatus of the present invention.
FIG. 2 is a perspective view of one embodiment of a toner guide member provided in a toner receiving port of a developing device in the image forming apparatus according to the present invention.
FIG. 3 is a plan view of one embodiment of a developing device main body in the image forming apparatus according to the present invention.
FIG. 4 is a perspective view of one embodiment of a stirring and conveying unit that forms a developing device in the image forming apparatus according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Developing device 2 Developing device main body 3 Toner container 4 Guide member 5 Toner receiving port 6, 7 Stirring and conveying means 8 Developing roller 9 Housing 10, 11 Conveying means

Claims (4)

A stirring and conveying means for supplying a developer to a developing roller for developing a latent image formed on the photoreceptor while stirring, and a detachable toner provided above the stirring and conveying means for supplying toner to a developing device A developing device in the image forming apparatus having a toner receiving port for receiving toner from the storage means;
A guide member is provided to surround the toner receiving port, guide the toner from the toner receiving port to the stirring and conveying means, and prevent toner from staying between the stirring and conveying means and the inner wall of the developing device. Developing device in an image forming apparatus. 2. The developing device in the image forming apparatus according to claim 1, wherein a scraper for scraping off the toner accumulated in the guide member is provided in the stirring and conveying means corresponding to the guide member installation site. The developing device according to claim 1, wherein the guide member is formed to diverge toward the agitating and conveying unit. 2. The developing device in the image forming apparatus according to claim 1, wherein the agitating / transporting unit side of the guide member has a shape along a rotating outer edge of the agitating / transporting unit.

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