JPH09160459A - Toner cloud recovering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent soiling in image forming device while solving the problem on noise and power consumption by setting a toner cloud suction force stronger at a part corresponding to the outside of the passing area of a transfer medium having a standard size set previously than at other parts in the cloud recovering aperture of a cloud recovering housing. SOLUTION: The toner cloud T uniformly suspending all over in the width direction of a latent image carrier 1 is sucked from the cloud recovering aperture 4a by suction force generated from a suction force imparting means 5. At such a time, a specified suction force distribution is previously set along in the width direction of the carrier 1 by a suction force distribution setting means 6, so that the stronger suction force than the part corresponding to the passing area is imparted to the part corresponding to the outside of the passing area of the transfer medium 7 having a standard size. As a result, the toner cloud T suspending at the part corresponding to the outside of the area is sucked in the housing 4 in full and the soiling in image forming device is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner cloud which is attached to a developing device used in an image forming apparatus such as a copying machine or a printer using electrophotography and collects a toner cloud generated from the developing device during a developing operation. Regarding improvement of recovery device.

[0002]

2. Description of the Related Art Conventionally, a developing device used in an image forming apparatus such as a copying machine or a printer using electrophotography has an opening for development generally facing a latent image carrier such as a photosensitive drum. A developing housing is provided, a developing roll is arranged facing the developing opening, and the developer contained in the developing housing is carried on the developing roll to develop to a developing area facing the developing opening. The agent is conveyed to visualize the electrostatic latent image on the latent image carrier.

In such a developing device, during the developing operation, the floating toner (toner cloud) of the developer flows out from the gap between the developing opening of the developing housing and the developing roll, so that the inside of the image forming apparatus is exposed. The technical problem of soiling arises.

Therefore, as a means for solving such a problem, conventionally, for example, one in which a toner cloud collecting device is attached to the lower part of the developing housing has been proposed. This toner cloud collecting device is integrally provided in the lower part of the developing housing, and has a suction port corresponding to at least a portion along the width direction of the latent image carrier of the developing opening edge of the developing device. The duct has a duct, a blower device provided on the back side of the duct, and a toner removing filter provided inside the duct and on the front side of the blower device (see, for example, Japanese Patent Laid-Open No. 4-223484). .

And, in the vicinity of the suction port in the duct,
A proper number of vertical air amount adjusting plates are provided at equal intervals along the axial direction of the developing roller, and the air amount at the suction port is set to be substantially uniform over the entire length of the suction port. There is.

In such a toner cloud collecting device, when the toner cloud flows out from the developing opening in association with the developing operation of the developing device, the toner cloud is sucked by the air suction force of the toner cloud collecting device into the duct through the air. Is sucked with. In this way, the toner cloud sucked into the duct is captured by the filter.

[0007]

However, as the number of times of image formation increases, a very small amount of toner is sequentially deposited on the paper transport guide member of the paper path located below the developing device. There was a phenomenon of going down.

More specifically, of the toner cloud flowing out of the developing opening, a very small amount of the toner cloud cannot be completely sucked by the toner cloud collecting device and falls onto the paper transport guide member. In the portion of the paper conveyance guide member that corresponds to the passage area (hereinafter referred to as the paper passage portion) of the standard-sized paper that is frequently used, the dropped toner adheres to the passing paper and is conveyed together with the paper. On the other hand, the toner is sequentially deposited on the portion of the paper transport guide member corresponding to the outside of the passage area of the standard size sheet (hereinafter referred to as the non-sheet passing portion). For this reason, in the non-sheet passing portion, the amount of accumulated toner increases as the number of times of image formation is repeated, and not only toner stains appear on the edge portion of standard size paper or a part of front surface or back surface of large size paper. However, the toner re-suspends due to mechanical vibration and adheres to the optical components and the like, which also directly causes deterioration of image quality.

In order to solve such a technical problem, it is conceivable to greatly increase the capacity of the blower device to suck the minute amount of toner completely without leaking.
With this type, as the capacity of the blower device is increased, there are many harmful effects such as excessive noise due to motor drive and enormous power consumption, and it is difficult to employ it in practice.

The present invention has been made to solve the above technical problems, and eliminates the toner accumulated on the paper path while solving the problems of noise and power consumption, and an image forming apparatus using the accumulated toner. An object of the present invention is to provide a toner cloud collecting device that effectively prevents dirt inside and deterioration of image quality.

[0011]

That is, as shown in FIG. 1, a toner cloud collecting apparatus according to the present invention is provided in a developing housing 2 having a developing opening 2a facing a latent image carrier 1. In a toner cloud collecting device which is arranged near the developing device 3 containing a developer containing at least toner and collects the toner cloud T flowing out from the developing opening 2a, at least the edge of the developing opening 2a. A cloud collection housing 4 having a cloud collection opening 4a corresponding to a portion along the width direction of the latent image carrier 1, and the toner cloud T from the cloud collection opening 4a toward the inside of the cloud collection housing 4. Of the transfer medium 7 having a preset reference size in the cloud collecting opening 4a It is characterized in that the suction force to the toner cloud T sites corresponding to the outside over the region has a suction force distribution setting means 6 is set larger than the other sites.

In such a technical means, as the developing device 3, the developing opening 2 facing the latent image carrier 1 is formed.
The latent image carrier 1 has a developing housing 2 in which a is opened.
Anything can be used as long as the above electrostatic latent image can be visualized, and any of developing by bringing a developer into contact with the surface of the electrostatic latent image and developing by non-contact can be used. The developer used in 3 may be a one-component developer, a two-component developer, a toner color, or the like.

The cloud collecting housing 4 may be any one that can effectively collect the toner cloud generated from the developing opening 2a, and at least along the width direction of the latent image carrier 1 at the edge of the developing opening 2a. If the cloud collecting opening 4a is opened corresponding to the above-mentioned portion, the cloud collecting opening 4a may be provided at a portion located downstream of the developing opening 2a in the rotational direction of the latent image carrier 1 or the developing opening 2a may be provided. It may be appropriately selected such that it is arranged in the upper and lower portions or it is arranged so as to cover the entire periphery of the developing opening 2a. The cloud collection housing 4 may have a duct shape or a simple box shape depending on the configuration of the suction force applying means 5.

Further, the suction force applying means 5 may be any means that can apply a suction force to the toner cloud T from the cloud recovery opening 4a toward the inside of the cloud recovery housing 4, for example, the cloud recovery housing 4 In a duct-like structure, a blower means is provided in this duct or in a communicating portion of the duct, and the air suction force by the blower means is used, or in the type in which the developer is a magnetic one-component toner, Alternatively, magnetic force generating means may be arranged in the cloud recovery housing 4 and the magnetic force generated by the magnetic force generating means may be used for the proper selection. In addition, the suction toner removal method may be appropriately selected. For example, in the air suction method, a filter may be interposed, or a blower unit may be provided with a toner recovery unit. Good. on the other hand,
In the magnetic force suction method, from the viewpoint of always maintaining the function of the magnetic force generating means in good condition, it is preferable to design so as to periodically remove the toner attached to the magnetic force generating means.

Further, as the suction force distribution setting means 6, the portion (corresponding to the passage of the reference size transfer medium 7) corresponding to the outside of the passage area of the preset reference size transfer medium 7 in the cloud collection opening 4a. (One or both sides of the area)
If the suction force with respect to the toner cloud T is set to be larger than that of other portions, it may be appropriately selected. For example, the suction force applying means 5 may be provided in the duct as the cloud collection housing 4 or in the communicating portion of the duct. In the type in which the blower means is provided as the above, the cloud collecting opening 4 of the duct as the cloud collecting housing 4 is provided.
An air flow rate adjusting member may be provided in the vicinity of a. Further, in the type using the magnetic force generating means as the suction force applying means 5, a predetermined magnetic force distribution may be applied to the magnetic force generating means. Good. The reference size of the transfer medium 7 may be arbitrarily set by the user, but it is preferable to select a standard size that is frequently used (for example, JIS standard A4 version) as the reference size.

In the technical means as described above, FIG.
The operation of the device invention will be described. When the developing device 3 executes a series of developing operations, the toner cloud collecting device starts a suction collecting operation to collect the toner cloud T generated from the developing opening 2a.

That is, a toner cloud is generated from the gap between the developing opening 2a of the developing housing 2 and the latent image carrier 1 along with the developing operation, and these toner clouds are spread over the entire width of the latent image carrier 1. Float uniformly over.

In this way, the floating toner cloud T is sucked from the cloud collecting opening 4a by the suction force of the suction force applying means 5. At this time, since the predetermined suction power distribution is set in advance along the width direction of the latent image carrier 1 by the suction force distribution setting means 6, compared with the portion corresponding to the passage area of the transfer medium 7 of the reference size. Thus, a larger suction force is applied to the portion corresponding to the outside of the region.

As a result, the toner cloud T floating in the area corresponding to the outside of the area is completely sucked into the cloud collecting housing 4 without leaking a very small amount, while the toner cloud T floats in the area corresponding to the area. Almost all of the toner cloud T to be sucked is sucked from the cloud collection opening 4a, but a very small amount of toner that is not recognized by the naked eye is not sucked, and a transfer medium conveyance guide member (not shown) to the paper path side. Fall upwards.

At this time, the toner does not drop at all in the portion corresponding to the outside of the passage area of the transfer medium 7 of the reference size in the transfer medium conveying guide member on the paper path side, while the transfer medium of the reference size is used. Although a very small amount of toner drops to the portion corresponding to the passage area of 7, the toner is conveyed together with the passing transfer medium 7. Therefore, the accumulation of the falling toner on the transfer medium transport guide member is effectively avoided.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a toner cloud collecting apparatus according to the present invention will be described in detail based on an embodiment shown in the accompanying drawings. First Embodiment FIG. 2 shows a first embodiment of a developing device to which the present invention is applied and a toner cloud collecting device attached thereto. In the drawing, the developing device has a developing housing 22 which is provided with a developing opening 22a facing the photosensitive drum 21 side and accommodates, for example, a two-component developer therein. Is a developing roll 23 which is arranged facing the developing opening 22a and conveys the developer in the direction of the arrow in the figure, a trimmer plate 24 which regulates the amount of the developer conveyed on the developing roll 23, and A pair of developer agitating and conveying augers, that is, a first auger 25 and a second auger 26, for conveying the stored developer in the developing roll 23 direction along the axial direction of the developing roll 23, And a paddle wheel 27 that supplies the developer, which is agitated and conveyed, to the developing roller 23. In this embodiment, the developing roll 23 includes a magnet roll 23a in which a plurality of magnetic poles are arranged along the peripheral surface and fixedly installed, and a non-rotatably arranged outside the magnet roll 23a. It is composed of a magnetic cylindrical developing sleeve 23b.

Next, a toner cloud collecting device arranged adjacent to such a developing device will be described. This toner cloud collecting device is provided with a developing housing 2
2 has a duct 31 provided along the outside of the lower wall portion. The duct 31 has a cover-shaped duct member attached to the outside of the lower wall of the developing housing 22, and has an opening area substantially corresponding to the axial (width direction) dimension of the photosensitive drum 21 at a portion facing the photosensitive drum 21. It has a suction port 32 and a discharge port 33 on the back side. A bellows-like pipe 34 is connected to the discharge port 33 portion of the duct 31, and a filter portion 35 accommodating a toner capturing filter 35a is replaceably housed in the bellows-like pipe 34.
Further, a blower device 37 for sucking air is communicatively connected to the filter portion 35 via a connecting pipe 36.

Furthermore, as shown in FIG. 3, in this embodiment, five air-conditioning plates 40 (specifically 40a to 40a) are provided in the air flow passage near the suction port 32 of the duct 31. 40 e) are arranged along the axial direction of the photosensitive drum 21. In the same figure, both side walls 31a, 31b in the width direction of the duct 31 and the air amount adjusting plate 40 (40a, 40)
Predetermined gaps are provided between the e) and the air amount adjusting plates 40 adjacent to each other. Among these gaps, in particular, the gap 41 between the one side wall 31a of the duct 31 and the air amount adjusting plate 40a is set larger than the other gaps 42.

Here, the air amount adjusting plate 40 is set in the above-described manner, as shown in FIG. 4, as the paper of a preset reference size (in the present embodiment, for example, the JIS standard is used). This is because in consideration of the passage locus on the paper path of A4 size), the air suction amount of the suction port 32 portion corresponding to the region where the reference size sheet does not pass is secured more than other portions.

More specifically, in the present embodiment, the paper 50 passing through the paper path is conveyed while positioning one widthwise side edge thereof on a predetermined positioning line 51, as shown in FIG. The positioning line 51 is set on the front side (Front side) of the operator of the image forming apparatus main body. Therefore, in the paper path, a region (non-sheet passing portion) 52 where the standard size sheet 50 does not pass is generated on the back side (Rear side) of the image forming apparatus main body, and the suction port 32 corresponding to the non-sheet passing portion 52. It is designed to increase the amount of air sucked in. In FIG. 4, reference numeral 54 is a chute (paper transport guide member) disposed below the developing device for guiding and transporting the paper 50, and 55 is a transfer charger for transferring the toner image on the photosensitive drum 21 to the paper 50. Reference numerals 56 and 56 denote peeling chargers that peel off the sheet 50 attached to the photosensitive drum 21.

Next, the operation of the toner cloud collecting apparatus according to this embodiment will be described. When the developing device performs a normal developing operation, the toner cloud flows out from the gap formed between the developing opening 22a of the developing housing 22 and the developing roll 23 and floats around. Due to the air suction force from the blower device 37, the floating toner flows from the suction port 32 of the duct 31 to the duct 31 together with the air.
It is sucked into.

At this time, the air amount by the air amount adjusting plate 40 is set to be larger in the gap 41 portion than in the other gap portions 42, so that the non-sheet passing portion 52 in the entire area of the suction port 32 is in the non-sheet passing portion 52. The corresponding portion will be given a larger suction force than the other portions.

As a result, the toner cloud floating in the portion corresponding to the non-sheet passing portion 52 is completely sucked into the duct 31 without leaking even a very small amount, while the passage area of the reference size sheet 50 is passed. Almost all of the toner cloud floating in the portion corresponding to the (paper passing portion) 53 is sucked into the duct 31 through the suction port 32 of the duct 31, but a small amount of toner that is not recognized by the naked eye is sucked. Instead, it falls toward the chute 54 or the like located below the developing device.

Therefore, the non-sheet passing portion 5 such as the chute 54 or the like.
The situation in which the toner falls onto the sheet 2 is completely avoided. On the other hand, although a very small amount of toner falls onto the sheet passing portion 53 as in the conventional case, it adheres to the sheet and is conveyed together with the sheet. Therefore,
Toner is not deposited on the chute 54 and the like, and a large-sized sheet is prevented from being contaminated during transportation, and the deposited toner is prevented from re-floating and adhering to optical components due to mechanical vibration or the like.

Next, the performance of the toner cloud collecting apparatus according to the first embodiment will be evaluated. FIG. 5 shows the first embodiment.
5A and 5B are views of the toner cloud collecting device of the comparative form seen from below. As a comparative form, as shown in FIG. 5A, the air suction amount is substantially uniform in the longitudinal direction of the suction port 32. In this embodiment, five air amount adjusting plates 40 ′ are evenly arranged as shown in FIG.
As shown in (b), the gap 41 between the one side wall 31a of the duct 31 and the air amount adjusting plate 40a is set to be 20 mm larger than that of the comparative example, and the other gaps 42 are compared with those of the comparative example. Then, the size is set to be larger by 5 mm.

In order to evaluate the performance of the toner cloud collecting apparatus of both types as described above, the wind speed measuring points (1) to (5) shown in FIG. When the wind velocity distribution over the longitudinal direction was examined, the results shown in Table 1 below were obtained. In addition, in order to objectively clarify the distribution result of the wind speed obtained in Table 1, it is shown in the graph of FIG.

[0032]

[Table 1]

As a result, in the present embodiment, the wind velocity, which is substantially uniform over the entire length of the suction port 32 in the comparative form, is dramatically measured at the measurement point corresponding to the non-sheet passing portion. It was confirmed to increase. This indicates that the air volume of the portion corresponding to the non-sheet passing portion is larger than that of the other portions. Further, in both modes, when the accumulation state of the toner on the chute 54 is examined after repeating the image forming times a predetermined number of times, in the comparison mode, the toner is accumulated on the non-sheet passing portion 52. However, in the present embodiment, the presence of toner on the chute 54 could not be visually confirmed. It should be noted that although a slight decrease in wind speed is seen from the vicinity of the center of the suction port 32 to the front side, it is considered that there is no particular problem because it is a portion corresponding to the sheet passing portion.

Second Embodiment FIG. 7 shows a developing device provided with a second embodiment of the toner cloud collecting device to which the present invention is applied. Note that components similar to those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and detailed description thereof is omitted here. The basic configuration of the developing device according to the second embodiment is substantially the same as that of the first embodiment, but unlike the first embodiment, in particular, a magnetic one-component toner is used as the developer and the developing roll 23 is accommodated. A box-shaped cloud collecting housing 61 bulging downward is formed on the lower side of the space, and an opening area substantially corresponding to the widthwise dimension of the photosensitive drum 21 is formed in a portion of the cloud collecting housing 61 facing the photosensitive drum 21. The cloud collecting opening 62 is opened, and the cloud collecting roll 63 is disposed in the cloud collecting housing 61.

In the present embodiment, the cloud recovery roll 63 has a magnet roll 63a in which a plurality of magnetic poles are arranged along the peripheral surface and fixedly installed, and the magnet roll 63.
It is composed of a conveying sleeve 63b which is rotatably arranged outside a. Furthermore, cloud collection housing 61
A scraper 64 that elastically contacts the surface of the cloud recovery roll 63 is disposed on the back side of the.

Further, as shown in FIG. 8, in the second embodiment, the magnetic force of the magnet roll 63a has a non-uniform magnetic force distribution along the axial direction of the magnet roll 63a. Specifically, of the magnetic forces over the entire area of the magnet roll 63a in the axial direction, the magnetic force of the portion corresponding to the non-sheet passing portion 52 described in the first embodiment is set to be larger than the other portions.

Next, the operation of the toner cloud collecting apparatus according to the embodiment will be described. Now, if the toner cloud flows out from the developing opening 22a when the developing device executes the developing operation, the toner cloud that has flowed out reaches the cloud collecting opening 62 while floating and reaches the magnetic force of the cloud collecting roll 63. Fall into the range of influence. Then, the magnetic force of the cloud collecting roll 63 acts on the toner particles, and the toner cloud is sucked and adsorbed on the surface of the cloud collecting roll 63.

At this time, since the magnetic force of the portion corresponding to the non-sheet passing portion 52 is set to be larger than that of the other portions, the toner cloud floating and dropping in the portion corresponding to the non-sheet passing portion is extremely small. The amount of toner is completely sucked and sucked from the cloud collection opening 62 to the cloud collection roll 63, while the toner cloud floating and falling at the portion corresponding to the paper passing portion 53 (see FIG. 4) is almost completely collected. Is sucked and absorbed by. Then, the toner adsorbed on the cloud collection roll 63 is scraped off by the scraper 64 and collected in the cloud collection housing 61.

It should be noted that a very small amount of toner that is not recognized by the naked eye of a very small part of the toner cloud that floats and falls in the area corresponding to the paper passing portion 53 is not sucked from the cloud recovery opening 62 and the chute 54, etc. However, in the same manner as in the first embodiment, there is no particular problem because it adheres to a sheet of paper that passes by each image formation and is removed each time.

Therefore, according to the second embodiment, as in the first embodiment, even if the number of times of image formation is large, the situation that the toner is accumulated on the chute 54 or the like can be surely avoided.

[0041]

As described above, according to the present invention,
Of the cloud collection openings in the cloud collection housing,
Since the suction force of the toner cloud of the portion corresponding to the area outside the preset reference size transfer medium is set to be larger than that of the other portion, the toner floating corresponding to the portion outside the area of the reference size transfer medium passage is set. It is possible to completely suck and collect the cloud without leakage, and as a result, it is possible to eliminate the toner stain inside the device corresponding to the outside of the passage area of the transfer medium of the reference size below the developing device.

Therefore, even if a large-sized transfer medium exceeding the reference size passes, it is possible not only to effectively avoid the situation where the transfer medium is contaminated with toner, but also the toner accumulated inside the apparatus is re-generated due to mechanical vibration or the like. Problems such as floating and adhering to optical components and the like, which directly deteriorate image quality, are also solved. Further, according to the present invention, it is not necessary to unnecessarily increase the capacity of the blower device in order to improve the collection state of the toner cloud, so that problems such as noise and power consumption due to motor driving do not particularly occur.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a schematic configuration of a toner cloud collecting device according to the present invention.

FIG. 2 is an explanatory diagram showing a toner cloud collecting device according to the first embodiment.

FIG. 3 is an explanatory diagram showing the inside of the duct of the toner cloud collecting apparatus according to the first embodiment as viewed from below.

FIG. 4 is an explanatory diagram showing a paper path portion inside the apparatus below the developing apparatus in the first embodiment.

FIG. 5 is an explanatory view showing the inside of the duct of the toner cloud collecting apparatus according to the first embodiment and the comparative embodiment as seen from below.

FIG. 6 is a graph showing measurement results of air flow rates at measurement points of the toner cloud collecting apparatus according to the first embodiment and the comparative embodiment.

FIG. 7 is an explanatory diagram showing a toner cloud collecting device according to a second embodiment.

FIG. 8 is an explanatory diagram showing a magnetic force distribution of the cloud recovery roll according to the second embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Latent image carrier, 2 ... Developing housing, 2a ... Developing opening, 3 ... Developing device, 4 ... Cloud collection housing, 4a
... Cloud collection opening, 5 ... Suction force applying means, 6 ... Suction force distribution setting means, 7 ... Transfer medium, T ... Toner cloud

Claims (3)

[Claims] 1. A developing device (3) in which a developer containing at least toner is contained in a developing housing (2) having a developing opening (2a) facing the latent image carrier (1). A toner cloud collecting device for collecting a toner cloud (T) flowing out from the developing opening (2a), the width of at least the latent image carrier (1) at the edge of the developing opening (2a). A cloud collection housing (4) having a cloud collection opening (4a) corresponding to a portion along the direction, and the toner cloud from the cloud collection opening (4a) into the cloud collection housing (4). The suction force applying means (5) that applies a suction force to (T) and the cloud recovery opening (4a) correspond to the area outside the passage area of the transfer medium (7) having a preset reference size. And a suction force distribution setting means (6) for setting the suction force of the other portion to the toner cloud (T) to be larger than that of the other portion. 2. The device according to claim 1, wherein the cloud collecting housing (4) is formed in a duct shape, and suction force applying means is provided in the duct as the cloud collecting housing (4) or in a communicating portion of the duct. While the blower means as 5) is arranged, an air volume adjusting member as suction force distribution setting means (6) is provided in the vicinity of the cloud collecting opening (4a) of the duct as the cloud collecting housing (4). Toner cloud collection device characterized by. 3. The cloud collecting opening (4a) of the cloud collecting housing (4) according to claim 1, wherein a magnetic one-component toner is used as a developer.
The toner cloud characterized in that the magnetic force generating means as the attracting force applying means (5) is provided facing the magnetic force generating means, and the magnetic force distribution is set as the attracting force distribution setting means (6) for the magnetic force generating means. Recovery device.