JPH0814735B2 - Toner suction device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a toner suction device, and in particular,
The present invention relates to a toner suction device which is arranged in the vicinity of a developing device that visualizes an electrostatic latent image formed on an image bearing member such as a photosensitive drum, and is suitable for sucking toner leaking from the developing device.

(Prior Art) As is well known, in an electrophotographic copying machine, a laser beam printer, etc., an electrostatic latent image formed on an image bearing member such as a photosensitive drum is visualized by a developing device.

A conventional developing device and a toner suction device for sucking toner leaking from the developing device will be briefly described below with reference to the drawings.

FIG. 10 is a side view of an example of the developing device and the toner suction device, and FIG. 11 is a bottom view of FIG. In FIG. 11, the image carrier 3 shown in FIG. 10 is omitted.

In each drawing, the housing of the developing device 4 is arranged adjacent to the image carrier 3. The housing has an opening on the surface facing the image carrier 3, and the developing roll (mag roll) 1 is exposed from the opening.

A magnet is arranged inside the developing roll 1, and the magnet holds the developer on the surface of the developing roll 1.

The surface of the developing roll 1 facing the image carrier 3 moves in the same direction as the surface of the image carrier 3, that is, the image carrier 3 rotates in the direction of arrow B. In this case, for example, it rotates in the direction of arrow A.

A toner suction device 5 is arranged on the lower surface of the developing device 4. The toner suction device 5 includes a duct 8 and a suction fan 7 connected to the duct 8. The duct 8 is arranged so that its suction port 6 faces an arbitrary bus line of the developing roll 1.

In the developing device 4 having the above-described configuration, as the developing roll 1 rotates, toner leaks from between the developing roll 1 and the housing of the developing device 4, or the developing roll 1 and the image bearing member 3 are separated during development. Although toner is scattered from between the two, since the toner is sucked into the duct 8 from the suction port 6 of the toner suction device 5, the electrophotographic copying machine,
The inside of the laser beam printer will not get dirty.

FIG. 12 is a side view of another example of the developing device and the toner suction device, and FIG. 13 is a bottom view of FIG. In FIGS. 12 and 13, the same reference numerals as those in FIGS. 10 and 11 represent the same or equivalent portions.

In FIGS. 12 and 13, a toner suction device 5A arranged on the lower surface of the developing device 4 includes three ducts 8A to 8C each having suction ports 6A to 6C, and a duct 8D for collecting the ducts 8A to 8C. , And a suction fan 7 connected to the duct 8D.

In this example, since the duct is divided into a plurality of parts, the toner suction device can be made smaller and lighter than the size of the developing roll 1.

Such a technique is disclosed in, for example, JP-A-59-182476.
No. 59-182477.

(Problems to be Solved by the Invention) The above-described conventional technique has the following problems.

As described above, as the developing roll 1 rotates, the toner leaks from between the developing roll 1 and the housing of the developing device 4, or the toner scatters from between the developing roll 1 and the image carrier 3 during development. However, the manner in which this toner dust (hereinafter referred to as a toner cloud) is generated differs between the both end sides of the developing roll 1 and the area inside thereof.

That is, due to the rotation of the developing roll 1 and the image carrier 3, an air flow is generated in the atmosphere around the developing roll 1. Is stronger.

Therefore, in the area on the central portion side of the developing roller 1, the amount of leaked toner is smaller than that on both end portions thereof, but the generated toner cloud flow is strong, so the toner cloud is sucked by the toner suction device. It is hard to be done.

When the suction force of the toner suction device is increased so that all of the toner cloud generated on the central portion side of the developing roll 1 can be sucked, the suction force is too strong at both ends of the developing roll 1, Not only the toner cloud generated at both ends of the developing roller 1 but also the toner inside the developing device may be forcibly sucked.

When the toner inside the developing unit is sucked to the outside of the developing unit, there is a possibility that the toner will adhere to the area of the image carrier 3 where the toner should not adhere.
There is a possibility that a white background portion on the recording paper may be stained and a so-called high background may occur.

 There is also a concern that the amount of toner consumed will increase.

Conversely, if the suction force of the toner suction device is lowered so that only the naturally occurring toner cloud is sucked at both ends of the developing roll 1 without forcibly sucking the toner from the inside of the developing device, It is not possible to suck all the toner cloud generated in the area on the central portion side of the roll 1, and the inside of the machine such as the electrophotographic copying machine and the laser beam printer may become dirty.

As described above, it is extremely difficult to set an appropriate suction force of the toner suction device, and it is not possible to reliably suck only the toner cloud over the entire axial direction of the developing roll 1.

The present invention has been made to solve the above problems.

(Means and Action for Solving Problems) In order to solve the above problems, the present invention provides a distance between the suction port of the duct of the toner suction device and at least one of the image carrier and the developing roll. Is set so that at least one end side of the developing roll is set to be larger than the center side of the developing roll, whereby suction of the toner cloud on at least one end side of the developing roll is performed. It is characterized in that the force can be set to be smaller than the suction force on the central portion side, and only the naturally occurring toner cloud can be reliably sucked.

(Example) Below, this invention is demonstrated in detail with reference to drawings.

FIG. 2 is a side view of the first embodiment of the present invention, and FIG. 1 is a bottom view of FIG. In FIG. 1, the image carrier 3 shown in FIG. 2 is omitted.

In FIGS. 1 and 2, an opening is formed on the surface of the developing device 4 facing the image carrier 3, and the developing roll 1 is exposed from the opening.

A toner suction device 15 is arranged on the lower surface of the developing device 4. The toner suction device 15 has suction ports 16A to 1A, respectively.
Three ducts 18A-18C with 6C, and the duct 18A
To 18C into one duct 18D, and the duct 18D
It consists of a suction fan 7 connected to D.

The ducts 18A to 18C are arranged so that the suction ports 16A to 16C thereof face an arbitrary bus line of the developing roll 1, respectively, but the suction ports 16A to 16C and the developing roll 1 and / or the image carrier are carried. The distance between the body 3 and the developing roll 1
Is set to be large on both end sides.
That is, in this embodiment, suction ports 16A and 16C
The distance between the developing roll 1 and / or the image carrier 3 is greater than the distance between the suction port 16B disposed between the suction ports 16A and 16C and the developing roll 1 and / or the image carrier 3. Is also set large.

With such a structure, assuming that the suction forces at the suction ports 16A to 16C are the same, the toner cloud generated from the gap between the developing roll 1 and the casing of the developing device 4 or the developing roll 1 The attracting force of the toner cloud generated between the developing roller 1 and the image carrier 3 on both end sides is smaller than the attracting force on the central portion of the developing roller 1. As a result, only the naturally occurring toner cloud can be surely sucked in all the regions of the developing roller 1 in the rotation axis direction, that is, both the central portion and both end portions thereof.

FIG. 3 is a schematic view of the second embodiment of the present invention,
It is a figure similar to a figure. In FIG. 3, the same symbols as those in FIG. 1 represent the same or equivalent portions.

In FIG. 3, the toner suction device 25 has suction ports 26A to 26A similar to the toner suction device 15 shown in FIG.
3 ducts 28A-28C with 6C and ducts 28A-2
It is composed of a duct 28D that combines the 8Cs into one, and a suction fan 7 connected to the duct 28D.

In this embodiment, the suction ports 26A and 26C of the ducts 28A and 28C arranged near both ends of the developing roll 1 are used.
Is formed such that the distance from the developing roll 1 and / or the image carrier 3 gradually increases toward both ends of the developing roll 1.

With this configuration, the suction force of the toner cloud gradually weakens toward both ends of the developing roll 1, so that only naturally occurring toner clouds are more reliably compared to the first embodiment. Can be aspirated.

FIG. 4 is a schematic view of a third embodiment of the present invention,
It is a figure similar to a figure. 4, the same reference numerals as those in FIG. 1 represent the same or equivalent parts.

In the first and second embodiments, the suction port of the toner suction device is formed such that the distance from the developing roll 1 and / or the image carrier 3 increases as it goes to both ends of the developing roll 1. Has been done. However, in the third embodiment, the suction port of the toner suction device 35 is
The developing roll 1 is formed so that the distance to the developing roll 1 and / or the image bearing member 3 becomes larger toward one end of the developing roll 1. That is, also in this embodiment, the toner suction device 35 includes three ducts 38A to 38C each having suction ports 36A to 36C, and the ducts 38A to 38C.
Each of the ducts is composed of a duct 38D that collects the
The suction ports 36A to 36C of 38A to 38C are formed so as to have the same distance to the developing roll 1 and / or the image bearing member 3, and are connected to the suction ports only on one end side of the developing roll 1. A notch indicated by reference numeral 36E is formed only in the suction port 36A of the duct 38A so that the distance between the developing roll 1 and / or the image carrier 3 becomes large.

The suction force of the toner suction device depends on the shape of the duct, the attachment position of the suction fan 7, or when there are a plurality of ducts as shown in FIGS. It is often affected by the distance between and, etc., and is not constant at each suction port.

Therefore, for example, when the suction force of the duct (duct 38A) facing one end of the developing roll 1 is greater than the suction force of the duct (duct 38C) facing the other end of the developing roll 1. As shown by reference numeral 36E in FIG. 4, a notch is provided in the suction port of the duct having a larger suction force, and only at one end of the developing roll 1,
The distance between the suction port and the developing roll 1 and / or the image carrier may be increased.

 FIG. 5 is a schematic view of the fourth embodiment of the present invention.

In the fourth embodiment, the toner suction device 45 is
It is composed of a duct 48 and a suction fan 7 connected to the duct 48.

Notches 46E and 46F are formed at both ends of the suction port 46A of the duct 48.

When the image carrier and the developing roll arranged facing the image carrier are short, the structure of the toner suction device can be simplified by configuring the toner suction device with one duct and the suction fan 7 as described above. And can be manufactured at low cost.

 FIG. 6 is a schematic view of the fifth embodiment of the present invention.

The fifth embodiment is a modification of the fourth embodiment.

The suction port 56 of the duct 58 of the toner suction device 55 is formed in a curved shape so that the distance to the developing roll 1 and / or the image carrier becomes larger toward the both ends.

Also in this example, the toner suction device shown in FIG.
Similar to 25, the suction force of the toner cloud is
Since the toner cloud becomes gradually weaker toward both end portions of the toner, only naturally occurring toner cloud can be reliably sucked.

Figures 7, 8 and 9 are schematic views of the sixth, seventh and eighth embodiments of the present invention. 7, 8, 9 that are the same as those in FIGS. 1, 3, 5 indicate the same or equivalent parts.

The toner suction devices 65, 75, and 85 in the sixth, seventh, and eighth embodiments of the present invention are provided with the guide vanes 9 in the ducts in the first, second, and fourth embodiments. Is the same as

In this way, by providing the guide vanes 9 in each duct, it is possible to make the flow rate of the suction air in each part of the duct suction port uniform.

Further, by providing the guide blades 9, it is possible to further weaken the suction force of the toner cloud toward both ends of the developing roll 1. That is, by arranging the guide vanes 9 so as to increase the loss (resistance) inside the duct toward the both ends of the developing roll 1, the suction force of the toner cloud on the both end sides of the developing roll 1 or the image carrier. Can be further reduced.

In the sixth, seventh and eighth embodiments of the present invention, the distance between the suction port of the duct and the developing roll 1 and / or the image carrier increases as the distance to both ends of the developing roll 1 increases. As described above, the shape of the suction port is set and the guide vanes 9 as described above are arranged in each duct. However, the present invention is not limited to this, and the suction port and The attraction force of the toner cloud on both end sides of the developing roll 1 may be reduced only by the guide blades 9 while keeping the distance between the developing roll 1 and / or the image carrier constant.

(Effects of the Invention) As is clear from the above description, according to the present invention, the following effects are achieved.

That is, since the suction force of the toner cloud in at least one end side region of the developing roll 1 is set to be smaller than the suction force in the central region of the developing roll 1, only the naturally occurring toner cloud is surely sucked. can do. As a result, the inside of the electrophotographic copying machine, the laser beam printer, or the like in which the developing device is arranged is contaminated with toner, or the toner is on the surface of the image carrier,
There is no risk that the toner adheres to the area that should not adhere and the white background on the recording paper becomes dirty.

[Brief description of drawings]

1 is a bottom view of FIG. 2, FIG. 2 is a side view of the first embodiment of the present invention, and FIGS. 3 to 9 are bottom views of the second to eighth embodiments of the present invention. FIG. 10 is a side view of an example of a conventional developing device and toner suction device, FIG. 11 is a bottom view of FIG. 10, and FIG. 12 is a side view of another example of a conventional developing device and toner suction device. FIG. 13 is a bottom view of FIG. 1 ... Developing roll, 3 ... Image carrier, 4 ... Developing device, 7
…… Suction fan, 9 …… Guide blade, 15,25,35,45,55,65,
75,85 …… Toner suction device, 16A-16C, 26A-26C, 36A-36
C, 46A, 56 ... Suction port, 18A-18D, 28A-28D, 38A-38D, 48,
58 …… Duct

Claims (2)

[Claims] 1. A duct having a suction port arranged so as to face one generatrix of a developing roll for visualizing an electrostatic latent image formed on an image carrier, and a suction means connected to the duct. In the toner suction device, the distance between the suction port of the duct and at least one of the image carrier and the developing roll is closer to at least one end side than the central side of the developing roll. Is set to be large, a toner suction device. 2. The toner suction device according to claim 1, wherein guide vanes are arranged in the duct.