JP2602988B2 - Toner collection device incorporated in electrostatic recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Overview] A toner collecting device incorporated in an electrostatic recording device such as an electrophotographic recording device, and a toner collecting device using an inside of a drum-shaped electrostatic latent image carrier as a toner collecting place. An electrostatic latent image carrier having the form of a drum is provided, which aims to provide a toner collecting device that can smoothly transport undeveloped toner into the electrostatic latent image carrier regardless of the diameter of the electrostatic latent image carrier. A first toner accommodating chamber provided in a part of the periphery of the electrostatic latent image carrier for accommodating undeveloped toner removed from the image carrier, and one end wall of the electrostatic latent image carrier A second toner accommodating chamber provided on the side of the image forming section and communicating with the inside of the electrostatic latent image carrier at a position of the rotation axis thereof and also communicating with the first toner accommodating chamber; Between the chamber and the second toner storage chamber A first toner conveying means for conveying the undeveloped toner in the first toner storage chamber to the second toner storage chamber via the first toner storage chamber, the second toner storage chamber and the inside of the electrostatic latent image carrier. And a second toner conveying means for conveying the undeveloped toner in the second toner accommodating chamber to the inside of the electrostatic latent image carrier through the communicating portion.

[Industrial applications]

The present invention relates to a toner collecting device incorporated in an electrostatic recording device such as an electrophotographic recording device.

In an electrostatic recording device, an electrostatic latent image is formed on the surface of an electrostatic latent image carrier, such as a photosensitive drum or a dielectric drum, and the electrostatic latent image is electrostatically developed with a charged developer, that is, a charged toner. Is done. Next, a recording medium such as recording paper is applied to the developed toner image, and a charge having a polarity opposite to that of the developed toner image is applied to the recording paper from the back surface, whereby the developed toner image is electrostatically transferred to the recording paper. The recording paper having the transferred toner image is separated from the electrostatic latent image carrier,
For example, the transferred toner image is sent to a heat fixing device or the like, where the transferred toner image is heat-fixed on recording paper.

In the transfer process of the developed toner image, the developed toner image is not completely transferred from an electrostatic latent image carrier such as a photosensitive drum or a dielectric drum to recording paper. Some of the toner particles forming the toner image remain as undeveloped toner without being transferred to the recording paper.
Needless to say, if the undeveloped toner is left attached to the electrostatic latent image carrier, the writing of the electrostatic latent image to that area will be hindered. It must be quickly removed from the body. Therefore, a developer collecting device for collecting undeveloped toner from the electrostatic latent image carrier is incorporated in the electrostatic recording device.

[Conventional technology]

Referring to FIG. 3, as an example of the electrostatic recording apparatus, a laser printer adopting an electrophotographic system is schematically shown, and this laser printer includes a photosensitive drum 10 as an electrostatic latent image carrier. During the recording operation of the laser printer, the photosensitive drum 10 is rotated in the direction of arrow A, and the photosensitive surface thereof is charged by a pre-charger 12 composed of, for example, a corona discharger, whereby an electrostatic latent image writing area, that is, The charged areas are sequentially formed on the photosensitive surface of the photosensitive drum 10. Although various types of photosensitive drums 10 are known, they are broadly classified into a type that forms a positively charged area and a type that forms a negatively charged area.

An electrostatic latent image is written on the charged area formed on the photosensitive surface of the photosensitive drum 10 by the laser beam scanning unit 14. The laser beam scanning unit 14 includes therein a laser beam generator, and an optical system that deflects the laser beam to scan the charged area of the photosensitive drum 10 along the generatrix with the laser beam from the laser beam generator. By flashing the scanning laser beam based on the video signal, a so-called dot image (binary image) is written to the charged area as an electrostatic latent image. In addition,
In FIG. 3, the scanning laser beam is indicated by the reference symbol LB.

The electrostatic latent image written by the laser beam scanning unit 14 is electrostatically developed by a developing device 16 with a developer, that is, a toner. The developing device 16 includes a container 16a that holds a developer, that is, a toner, and a developing roller 16b that is driven to rotate in the direction of arrow B in the container 16a. As shown in the drawing, a part of the developing roller 16b is exposed from the container 16a to face the photosensitive drum 10, and the developing roller 16b
b is rotated in the direction of arrow B. When a two-component developer is used as the developer, the developing roller 16b is configured as a roller with a built-in magnet. At this time, the magnetic carrier in the two-component developer forms a so-called magnetic brush on the peripheral surface of the roller with a built-in magnet. Then, the toner particles in the two-component developer are conveyed toward the photosensitive drum 10 by the magnetic brush. On the other hand, when a non-magnetic-component developer consisting only of toner particles is used, the developing roller 16b is formed as an elastic rubber roller, and the toner particles are conveyed to the photosensitive drum 10 by a frictional force by the rubber surface of the elastic rubber roller. Is done. In any case, when the toner particles transported by the developing roller 16b, that is, the colored resin fine particles reach the area where the developing roller 16b and the photosensitive drum 10 face each other, the toner particles electrostatically adhere to the electrostatic latent image, and Develops the electrostatic latent image to obtain a toner image.

The thus-obtained developed toner image is
When the developing toner image reaches the transfer unit 18 by the rotation of, the developed toner image is transferred to the recording paper there. The transfer unit 18 is formed of, for example, a corona discharger, and the recording paper is sent between the photosensitive drum 10 and the transfer unit 18. When the recording paper passes between the photosensitive drum 10 and the transfer device 18, the recording paper is given a charge having a polarity opposite to that of the developed toner image by the transfer device 18, whereby the developed toner image is transferred from the photosensitive drum 10 side. It is electrostatically transferred to the recording paper side. The recording paper is held as a stacked body in the paper feed cassette 20, and is fed one by one from the feed roller 20a. The recording paper fed out in this manner is guided between the photosensitive drum 10 and the transfer device 18 by the guide roller 20b and the like. In FIG. 3, the moving path of the recording paper is shown by a dashed line.

The recording paper having the transferred toner image is sent to a heat fixing device 22, and the heat fixing device 22 includes a heat roller 22 a and a backup roller 2.
2b. When the recording paper passes between the heat roller 22a and the backup roller 22b, the toner particles forming the transfer toner image are thermally fused by the heat roller 22a, whereby the transfer toner image is thermally fixed on the recording paper. The recording paper with the fixed toner image is stored in the recording paper tray 24.
Is discharged on top.

When the developed toner image is transferred onto the recording paper by the transfer device 18, a part of the toner particles forming the developed toner image remains on the photosensitive drum 10 as undeveloped toner. Such undeveloped toner is removed from the photosensitive drum 10 by a toner scraping blade 26 formed of a suitable rubber material, for example, a urethane rubber material, and is temporarily stored in a toner storage chamber 28. In the example shown in FIG. 3, the toner accommodating chamber 28 includes a part of a casing 30 that covers approximately half of the photosensitive drum 10 for accommodating the pre-charger 12 and the transfer unit 18 together with a pair of casings 30 attached to the inner wall surface thereof. The toner scraping blade 26 is defined by the partition wall curved plates 30a and 30b.
Installed along the inside edge of a. It is also possible to remove the undeveloped toner using a fur brush or the like instead of the toner scraping blade 26.

The undeveloped toner temporarily stored in the toner storage chamber 28 must be quickly recovered. However, it is known that a toner recovery tank (not shown) is provided near the photosensitive drum 10 as a recovery place. Have been. In this case, the toner storage chamber 28 and the toner collection tank are connected by a toner discharge pipe, and a helical spring is stored in the toner discharge pipe as toner conveying means. The helical spring also extends into the toner storage chamber 28, and by rotating the helical spring, undeveloped toner is sequentially guided from the toner storage chamber 28 to the toner collection tank. As a problem of such a toner recovery device, it is necessary to additionally provide a toner recovery tank, which requires an installation space for the toner recovery tank, which hinders miniaturization of the electrostatic recording apparatus itself. (In recent years, electrostatic recording devices such as electrophotographic printers have tended to be miniaturized.) In addition, the cost of the electrostatic recording device has been reduced due to the use of an additional toner collection tank. There is an increasing point.

Therefore, as shown in FIGS. 4 (a) and 4 (b), it has been proposed to use the inside of the photosensitive drum 10 as a place for collecting undeveloped toner. As shown in FIGS. 4A and 4B, the side wall 30c of the casing 30
A U-shaped curved tube 32 is attached to (the side wall 30c defines one side space of the toner storage chamber 28), and one end 32a thereof is communicated with the toner storage chamber 28 through the side wall 30c. , The other end 32b is connected to the side wall 30c and the photosensitive drum 10
And is extended into the photosensitive drum 10 through the center of the one end wall 10a. As shown in FIG. 4 (b), a bearing 34 is provided around the center through hole of the end wall portion 10a of the photosensitive drum 10, whereby the photosensitive drum
In 10, the other end 32 b of the U-shaped curved tube 32 is communicated with the toner storage chamber 28 through the side wall 30 c, and is rotatable around the other end 32 b. A spiral spring 36 is provided in the toner storage chamber 28.
, One end of which is fixed to the rotating disk element 38, and the other end of which extends through the U-shaped curved tube 32 into the photosensitive drum 10. The rotating shaft 38a of the rotating disk element 38 passes through a partition 30d that defines the other side space of the toner storage chamber 28, and a gear 38b is attached to an outer end thereof. The gear 24b is the other end wall 10b of the photosensitive drum 10.
This gear 1 is engaged with a gear 10c mounted on the side.
0c is also engaged with a drive gear (not shown) for driving the photosensitive drum 10 to rotate. When the photosensitive drum 10 is driven to rotate, the rotational movement is transmitted to the spiral spring 36 via the gear 24b and the rotating disk element 38, whereby the undeveloped toner in the toner accommodating chamber 28 is sequentially placed inside the photosensitive drum 10. Sent.

[Problems to be solved by the invention]

In the toner collecting device as shown in FIGS. 4A and 4B, since the inside of the electrostatic latent image carrier, that is, the photosensitive drum 10 is used as a toner collecting place, additional toner collecting is performed. The need for a tank can be eliminated, which can contribute to miniaturization of the electrostatic latent image device and can reduce the manufacturing cost. However, as the electrostatic latent image device becomes smaller and the photosensitive drum 10 has a smaller diameter,
The problem is that the curvature of the curved tube 32 becomes large, and the transportability of the undeveloped toner there is deteriorated. That is, when the diameter of the photosensitive drum 10 is large, the curvature of the U-shaped curved tube 32 can be reduced, so that the undeveloped toner can move relatively smoothly there, but the curvature of the U-shaped curved tube 32 increases. As a result, the transport resistance of the undeveloped toner there increases, and as a result, the undeveloped toner tends to be stuck and clogged in the U-shaped curved tube 32.

Accordingly, an object of the present invention is a toner recovery device that uses the inside of a drum-shaped electrostatic latent image carrier as a toner recovery location, regardless of the diameter of the electrostatic latent image carrier. An object of the present invention is to provide a toner collecting device configured to smoothly transport undeveloped toner therein.

[Means for solving the problem]

The toner collecting device according to the present invention includes a first toner collecting device provided adjacent to the periphery of the electrostatic latent image carrier for accommodating undeveloped toner removed from the drum-shaped electrostatic latent image carrier.
And the first toner storage chamber, which is provided on one end wall of the electrostatic latent image carrier and communicates with the interior of the electrostatic latent image carrier at the rotation axis thereof. The second toner storage chamber communicated with the first toner storage chamber and the undeveloped toner in the first toner storage chamber through the communication portion between the first toner storage chamber and the second toner storage chamber. The first toner conveying means for conveying the toner to the storage chamber, and the undeveloped toner in the second toner storage chamber through the communicating portion between the second toner storage chamber and the inside of the electrostatic latent image carrier. And a second toner conveying means including a tubular element and a screw element disposed in the tubular element for conveying the toner into the electrostatic latent image carrier, and extending into the second toner accommodating chamber. The end of the tubular element present is cut off at its upper side to form a gutter-like section, At one end of the screw element of the second conveying means impeller element rotating in the second toner housing chamber is provided by the impeller element, the second
The undeveloped toner in the toner storage chamber is guided to the trough-shaped portion.

[Action]

As is apparent from the above configuration, in the toner recovery device according to the present invention, the undeveloped toner removed from the electrostatic latent image carrier and stored in the first toner storage chamber is first discharged to the first toner storage chamber.
From the first toner storage chamber to the second
And then conveyed from the second toner chamber to the inside of the electrostatic latent image carrier by the second toner conveying means.

〔Example〕

Next, an embodiment of the toner collecting apparatus according to the present invention will be described with reference to FIGS. 1 (a), 1 (b) and 2 of the accompanying drawings.

FIGS. 1 (a) and 1 (b) correspond to FIGS. 4 (a) and 4 (b), respectively. A casing 42 for covering the portion is provided in substantially the same manner as the casing 30 shown in FIGS. 3, 4 (a) and 4 (b), in which a pre-charger and a transfer charger are provided. They are arranged as in the case of FIG. A first toner storage chamber 44 is formed in the casing 42 in substantially the same manner as the toner storage chamber 28 shown in FIG. 3, and a toner scraping blade or a fur brush is provided therein. The undeveloped toner is removed from the photosensitive drum 40 by the
Housed in 44.

A second toner storage chamber 46 is provided in a side wall 42a of the casing 42 (the side wall 42a defines one side space of the first toner storage chamber 44), and the second toner storage chamber 46 is provided.
Is formed by attaching a cover element 48 to the side wall 42a. That is, the cover element 48 includes a peripheral wall portion 48a having a substantially oval cross section, and a closing wall portion 48b closing one opening side of the peripheral wall portion 48a, and the other opening side of the peripheral wall portion 48a. Is applied to the side wall 42a of the casing 42 to obtain the second toner storage chamber 46. In FIGS. 1 (a) and 2, the cover element 48 is shown with the closing wall 48a removed therefrom. The first toner storage chamber 44 and the second toner storage chamber 46 are formed by a casing.
The communication holes 42b formed in the side wall portions 42a of the 42 communicate with each other.

Further, the second toner accommodating chamber 46 is communicated with the inside of the photosensitive drum 40 at the center of one end wall 40a of the photosensitive drum 40. Specifically, the side wall portion 42a of the casing 42
By forming through-holes coaxial with the rotation axis of the photosensitive drum 40 in the end face wall portion 40a of the photosensitive drum 40 and inserting the tubular element 50 into the through-holes, the photosensitive drum 40
And the second toner accommodating chamber 46 are in communication with each other. The tubular element 50 is provided with a flange 50a, by which the tubular element 50 is fixed to the side wall 42a of the casing 42, for example by welding. As can be seen from FIGS. 1 (a) and 2, one portion of the tubular element 50, namely the second
The upper half is cut off on the side protruding into the gutter-shaped part 50.
b. A bearing 52 is provided in a through hole formed in the end face wall 40a of the photosensitive drum 40 to insert the other part of the tubular element 50, whereby the end face wall 40a is rotatable about the tubular element 50. Supported.

In order to transport the undeveloped toner in the first toner storage chamber 44 to the second toner storage chamber 46, the first toner transport screw element 54 is connected to the first toner storage chamber 44 through the communication hole 42b. And the second toner storage chamber 46. One end of the first toner conveying screw element 54 is rotatably inserted into and supported by a partition 42c defining the other side space of the first toner accommodating chamber 42, and has a gear 56 at its outer end. Is attached. The gear 56 is the photosensitive drum 40
Is engaged with a gear 58 attached to the other end wall portion 40b side, and this gear 58 is also engaged with a drive gear (not shown) for driving the photosensitive drum 40 to rotate. When the photosensitive drum 10 is driven to rotate, its rotational movement is
Is transmitted to the first toner conveying screw 54 via
As a result, the undeveloped toner in the first toner storage chamber 28 is sequentially sent to the second toner storage chamber 46.

To transport undeveloped toner in the second toner storage chamber 46 therefrom to the interior of the photosensitive drum 40, a second toner transport screw element 60 is passed through the tubular element 50 and the second toner storage chamber 46 and The photosensitive drum 40 extends between itself and the inside. One end of the second toner conveying screw element 60 is supported in a cantilever manner at the center of rotation of the end face wall 40b of the photosensitive drum 40, whereby the second toner conveying screw element 60 is And the undeveloped toner in the second toner storage chamber 46 is conveyed into the photosensitive drum 40. An impeller element 62 is provided at the other end of the second toner conveying screw element 60. The impeller element 62 has a disk 62a fixed to the other end thereof, and a disk 62a attached to the disk 62a. A pair of diametrically mounted vanes 62b
Consists of When the impeller element 62 is rotated together with the second toner conveying screw element 60, the undeveloped toner in the second toner accommodating chamber 46 is pumped up by the impeller plate 62b of the impeller element 62 to form the tubular element 50. Of the gutter 50b.

In the above-described embodiment, the toner conveying screw elements 54 and 60 are used as toner conveying means. However, other types of toner conveying means, for example, a helical screw as shown in FIG. 4 (b) may be used. Needless to say.

In the above-described embodiment, the toner conveying screw elements 54 and 60 are supported in a cantilever manner, respectively.However, the toner conveying screw elements 54 and 60 are supported with respect to the closing wall 48b of the cover element 48. May be rotatably supported.

Further, in the above-described embodiment, the undeveloped toner in the second toner accommodating chamber 46 is pumped up by the impeller element 62 and guided into the gutter-like portion 50b of the tubular element 50. It is also possible to omit 62. In this case, the tubular element
The gutter 50b is omitted and the peripheral wall 48a of the cover element 48 is omitted.
Preferably, the lower portion (in FIG. 1 (a)) is brought closer to the opening side of the tubular element 50, so that undeveloped toner can be quickly introduced into the opening.

Further, in the above-described embodiment, both the toner conveying screw elements 54 and 60 are rotated by using the rotational movement of the photosensitive drum 40. However, if necessary, the toner conveying screw elements 54 and 60 are exposed to light. The drum 40 may be rotated independently of the rotational movement.

〔The invention's effect〕

As is apparent from the above description, in the toner recovery device according to the present invention, the second toner storage chamber is interposed between the first toner storage chamber and the electrostatic latent image carrier, so that The developed toner can be smoothly transported from the first toner storage chamber to the inside of the electrostatic latent image carrier without being stopped halfway. In particular, when the toner recovery device according to the present invention is applied to a miniaturized electrostatic recording device, the prompt recovery of the undeveloped toner can be reliably achieved.

Further, according to the present invention, a combination of an impeller and a gutter-shaped tubular element is used for transporting the toner from the second toner storage chamber to the inside of the electrostatic latent image carrier. Not only can the toner be transported smoothly, but also the toner collection efficiency can be extremely increased.

[Brief description of the drawings]

FIG. 1A is a side view of a recording unit of an electrophotographic printer in which a toner collecting device according to the present invention is implemented, and FIG.
FIG. 2 is a sectional view taken along the line Ib-Ib in FIG.
FIG. 3A is a perspective view of a recording unit of the electrophotographic printer shown in FIG. 1A and FIG. 1B, FIG. 3 is a schematic diagram of an electrophotographic laser printer having a conventional toner collecting device, and FIG. FIG. 4A is a side view of a recording unit of the electrophotographic laser printer shown in FIG. 3, and FIG. 4B is a sectional view taken along line IVb-IVb in FIG. 4A. 40 photosensitive drum, 40a end wall, 42 casing, 42a side wall, 42b communication hole, 42c partition wall, 4
4 First toner storage chamber, 46 Second toner storage chamber, 48 Cover element, 48, 48a Peripheral wall, 48a, 48
b: closed wall, 48b, 50: tubular element, 50a: flange, 50b: gutter, 52: bearing, 54: first
, A gear, 58, a gear, 60, a second screw element for toner conveyance, 62
Impeller element, 62a ... disk, 62a, 62b ... impeller.

Claims (4)

(57) [Claims] A first toner accommodating chamber provided adjacent to the periphery of the electrostatic latent image carrier for accommodating undeveloped toner removed from the drum-shaped electrostatic latent image carrier; ,
The electrostatic latent image carrier is provided on one end face wall side, and is communicated with the inside of the electrostatic latent image carrier at a position of its rotation axis and also with the first toner storage chamber. The first toner storage chamber and the first toner storage chamber through a communicating portion between the first toner storage chamber and the second toner storage chamber.
A first toner transport unit for transporting undeveloped toner in the toner storage chamber to the second toner storage chamber;
A tubular element for transporting undeveloped toner in the second toner storage chamber to the inside of the electrostatic latent image carrier through a communication portion between the toner storage chamber of the second embodiment and the inside of the electrostatic latent image carrier. And a screw element disposed within the tubular element.
And an upper end of the end of the tubular element extending into the second toner storage chamber is cut off to form a gutter-like portion. At one end, an impeller element that rotates in the second toner storage chamber is provided, and the impeller element guides undeveloped toner in the second toner storage chamber to the gutter-shaped portion. A toner collecting device characterized by the above-mentioned. 2. The toner recovery device according to claim 1, wherein said first toner conveying means extends between said first toner storage chamber and said second toner storage chamber through their communicating locations. And a tubular element of the second toner transporting means, wherein the tubular element of the second toner transporting means communicates between the first toner storage chamber and the inside of the electrostatic latent image carrier. A toner collection device provided coaxially with a rotation axis of the electrostatic latent image carrier. 3. The toner recovery device according to claim 2, wherein a rotational movement of said electrostatic latent image carrier is transmitted as a rotational driving force of said first toner conveying screw element to the first toner conveying screw element. A toner collecting device, wherein a gear mechanism is interposed. 4. The toner collection device according to claim 2, wherein one end of the second toner conveying screw element is rotated at a rotation center of the other end wall of the electrostatic latent image carrier to rotationally drive the second toner conveying screw element. Wherein the toner collecting device is supported in a cantilever manner.