JP3702930B2 - Toner recovery device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a toner recovery device that recovers toner remaining on an image carrier such as a photosensitive drum or an intermediate transfer member in a surface image forming apparatus such as an electrophotographic copying machine or a laser printer.
[0002]
[Prior art]
2. Description of the Related Art A surface image forming apparatus such as an electrophotographic copying machine or a laser printer is provided with a toner collecting apparatus that collects residual toner attached on an image carrier such as a photosensitive drum or an intermediate transfer member. The conventional toner recovery device is configured such that toner scraped off from the surface of the image carrier by a cleaning blade or the like is sent into a recovery container by a feed roller or the like.
[0003]
Here, if the collection container continues to be used in a full state, the collected toner protrudes from the container and contaminates the inside of the apparatus and the recording paper. Therefore, for example, Japanese Utility Model Laid-Open No. 1-142970 proposes a toner recovery device including a sensor for detecting that the inside of the recovery container is filled with toner.
[0004]
Further, when the collected toner is not uniformly deposited in the collecting container and the position where the accumulation amount is high is the detection position by the sensor, full detection is performed even though there is a recovery capacity. On the contrary, if the position where the accumulation amount is high is other than the detection position, there may be a problem that the recovered toner overflows from the recovery container before fullness is detected.
[0005]
In order to solve such problems, for example, in Japanese Patent Publication No. 5-23437, as shown in FIG. 9, a spiral conveyance body 52 is provided in the collection container 50 and dropped from the toner collection port 54. A toner collecting device is disclosed in which the collected toner is uniformly deposited in a collecting container 50 by conveying the collected toner to the opposite side by a spiral conveying body 40.
[0006]
Further, as described above, when the spiral portion is provided in the entire spiral transport body, the toner transport force of the spiral transport body is increased, so that the toner density is increased on the opposite side of the collection container, and this is the spiral transport body. In some cases, the rotation of the spiral conveyance body is hindered by acting as a rotational load. Therefore, in the above-described prior art, as shown in FIG. 10, a toner recovery device provided with a spiral conveyance body 56 in which a spiral portion is partially thinned is proposed.
[0007]
[Problems to be solved by the invention]
The above-described prior art functions effectively when the amount of collected toner is relatively small. However, when the amount of collected toner further increases, as shown in FIG. 11, the spiral portion 58 is formed in a region where the toner density is high. Since the rotational load is increased due to being buried, there is a problem that the rotational driving unit of the spiral conveyance body needs to be enlarged or the strength of the spiral conveyance body itself must be increased.
[0008]
SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a toner recovery device in which the rotational load applied to the spiral conveyance body by the recovered toner is always maintained properly.
[0009]
[Means for Solving the Problems]
In order to achieve the above-described object, the present invention is used in an image forming apparatus, and in a toner collecting apparatus that collects toner removed from the surface of an image carrier of the image forming apparatus, a toner collecting unit that collects the collected toner. A spiral conveyance body provided rotatably with respect to the container and the toner collection container, wherein the spiral conveyance body does not have a spiral portion in a predetermined range from an end portion on the conveyance direction side of the helical conveyance body And a toner collection port opened on the spiral portion side of the spiral conveyance body of the toner collection container.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a configuration of a main part of a full-color printer provided with a toner recovery device to which the present invention is applied.
[0012]
A photosensitive drum 1 as an image carrier is provided with a charging roll 2 and a laser scanner (ROS) 3. The surface of the photosensitive drum 1 is uniformly charged by a charging roll 2 and is exposed by a laser scanner 3 driven in accordance with a video signal. The photosensitive drum 1 is rotated in the direction of arrow A by a driving means (not shown), and a known electrophotographic process proceeds.
[0013]
In the next stage of the laser scanner 3, a developing device 4 having developing devices 4a, 4b, 4c and 4d corresponding to the respective colors of black (K), yellow (Y), magenta (M) and cyan (C) is arranged. The electrostatic latent image formed on the photosensitive drum 1 is developed by any developing device to form a toner image. Therefore, for example, if the electrostatic latent image written on the photosensitive drum 1 corresponds to yellow image information, the electrostatic latent image is developed by the developing device 4a provided with yellow (Y) toner, A yellow toner image is formed on the photosensitive drum 1.
[0014]
A belt-like intermediate transfer member 5 is disposed in contact with the surface of the photosensitive drum 1. This intermediate transfer member 5 is stretched around a plurality of rolls 6, 7, 8, 9 and rotates in the direction of arrow B. The toner image formed on the photosensitive drum 1 is primarily transferred from the photosensitive drum 1 to the surface of the intermediate transfer member 5 at a primary transfer position where the photosensitive drum 1 and the intermediate transfer member 5 are in contact with each other. At the primary transfer position, a transfer roll 10 is disposed on the back side of the intermediate transfer member 5, and a voltage having a polarity opposite to the charging polarity of the toner on the photosensitive drum 1 is applied to the photosensitive drum 1. The toner image is electrostatically attracted to the intermediate transfer member 5. At this time, residual toner that is not transferred to the intermediate transfer member 5 and remains on the photosensitive drum 1 is cleaned by the first cleaning unit 11.
[0015]
In the case of forming a single color image, the unfixed toner image primarily transferred to the intermediate transfer member 5 is immediately secondary transferred to the paper P. However, when forming a color image in which a plurality of color toner images are superimposed. The toner image formation on the photosensitive drum 1 and the primary transfer of the toner image are repeated for the number of colors. For example, when a full color image is formed by superimposing four color toner images, black, yellow, magenta and cyan unfixed toner images are formed on the photosensitive drum 1 for each rotation, and these unfixed toners are formed. The image is sequentially primary transferred onto the intermediate transfer member 5.
[0016]
On the other hand, since the intermediate transfer member 5 rotates at the same cycle as the photosensitive drum 1 while holding the black unfixed toner image that has been primarily transferred first, the intermediate transfer member 5 is rotated on the intermediate transfer member 5 every rotation. The yellow, magenta and cyan unfixed toner images are transferred onto the black unfixed toner image.
[0017]
The unfixed toner image primarily transferred to the intermediate transfer body 5 in this way is conveyed to a secondary transfer position facing the conveyance path of the paper P as the intermediate transfer body 2 rotates. A transfer roll 12 is disposed at the secondary transfer position, and the transfer roll 12 contacts the intermediate transfer body 5 when an unfixed toner image is transferred to a sheet. A sheet P conveyed by a sheet conveying unit (not shown) is sandwiched between the transfer roll 12 and the intermediate transfer member 5. Further, at the secondary transfer position, a backup roll 8 that constitutes a counter electrode of the transfer roll 12 is disposed on the back side of the intermediate transfer body 5. When a voltage is applied between the transfer roll 12 and the backup roll 8, the intermediate transfer is performed. The unfixed toner image carried on the body 5 is electrostatically transferred onto the paper P at the secondary transfer position.
[0018]
At this time, residual toner that is not transferred onto the paper P and remains on the intermediate transfer member 5 is cleaned by the second cleaning unit 13. The sheet P that has passed through the secondary transfer position is fixed by a fixing device (not shown), and the transferred image is discharged from the apparatus main body.
[0019]
Next, a collection device for the toner collected in the first and second cleaning units 11 and 13 will be described. The toner scraped off from the photosensitive drum 1 by the first cleaning unit 11 is discharged from the cleaning unit 11 by the first transport unit 14. The toner discharged from the first cleaning unit 11 is pushed out to the connecting unit 15, and the conveyance direction is reversed by the second conveyance unit 16 and collected in the toner collection box 17. The first transport unit 14 includes a screw or coil-shaped auger, that is, a spiral rotating body, and the rotating body is exposed in the cleaning unit 11 to receive toner falling from above.
[0020]
On the other hand, the toner scraped off by the second cleaning unit 13 is discharged from the cleaning unit 13 by the third transport unit 21, transported by the fourth transport unit 22, and collected in the toner recovery box 17. Is done. The third transport unit 21 has the same structure as the first transport unit 14. The third transport unit 21 is coupled to the fourth transport unit 22 via a connecting portion (pipe) 23 that hangs down from one end thereof. The fourth transport unit 22 is a pipe containing a coiled auger, and the upper end of the pipe is inserted into the toner recovery port 25 of the toner recovery box 17. A gear 24 is coupled to the end of the auger included in the fourth transport unit 22, and a drive source (not shown) is coupled to the gear 24.
[0021]
Next, the configuration of the toner collection box 17 will be specifically described. FIG. 2 is a cross-sectional view showing the configuration of the toner collection box 17 according to an embodiment of the present invention, and the same reference numerals as those described above represent the same or equivalent parts.
[0022]
The toner collection box 17 of the present invention is arranged along the longitudinal direction in a rectangular parallelepiped toner collection container 171 and the toner collection container 171, and both ends thereof are rotatably supported by the opposing surfaces of the toner collection container 171. A spiral conveyance body 172, a fullness detection device 30 attached to the upper portion of the toner recovery container 171 and detecting whether or not the recovery toner has accumulated to the full position in its own projection area, and one end side of the toner recovery container 171 And a shielding plate 174 erected downward from the upper portion of the toner collection container 171 between the full detection device 30 and the toner collection port 25. One end of the fourth transport unit 22 is inserted into the toner recovery port 25 from the outside of the container.
[0023]
The fullness detection device 30 includes a transparent or translucent housing 301 provided so as to protrude upward through an opening provided in an upper portion of the toner recovery container 171, and the front side and the back side of the drawing with the housing 301 interposed therebetween. A pair of transmissive optical sensors (not shown), a float portion 304 that is floatably disposed in the toner collection container 171, and a stand on the float portion 304 corresponding to the housing portion 301. And a light shielding protrusion 305 provided. The float unit 304 is suspended from the upper part of the toner collection container 171 via flexible sheets 302 (302a, 302b) fixed to both ends thereof.
[0024]
FIG. 3 is a perspective view for explaining a method of suspending the float unit 304. The flexible sheet 302 has bent portions 310 and 311 at its upper and lower ends, respectively, and one bent portion 310 is fixed to the upper inner wall of the toner collection container 171 with a double-sided tape or the like, and the length of the float portion 304 is long. The other bent portion 311 is fixed to both ends in the direction with a double-sided tape or the like. Such a full detection device is described in detail in Japanese Patent Application Laid-Open No. 62-94883 by the present applicant.
[0025]
The spiral conveyance body 172 is rotationally driven so that the collected toner is conveyed through the container 171 from the toner collection port 25 side to the opposite side by the rotational movement. Here, in the spiral conveyance body 172 of this embodiment, no spiral portion is formed in the range of the distance d from the end portion in the conveyance direction opposite to the toner collection port 25 side. More specifically, the spiral conveyance body 172 does not have a spiral portion in the range from the end portion in the conveyance direction to the vicinity of the projection region of the fullness detection device 30.
[0026]
In other words, in this embodiment, the spiral portion of the spiral conveyance body 172 is formed only on the toner collection port 25 side from the projection area including the projection area of the fullness detection device 30. In the spiral portion, it is desirable that the pitch P is longer than 1.2 times the outer diameter R.
[0027]
Next, with reference to FIGS. 4 to 8, how the toner is collected in the toner collection box 17 having the above-described configuration will be described with time. When the toner starts to be collected, the collected toner 100 starts to be deposited in the lower part of the opening end of the fourth conveying unit 22 in the toner collecting container 171 as shown in FIG. Thereafter, as illustrated in FIG. 5, when the collection toner collects and the height reaches the position of the spiral conveyance body 172, the collection toner starts to be conveyed by the spiral conveyance body 172.
[0028]
As the toner collection progresses, the collected toner starts to be deposited on the conveyance direction side end in the container as shown in FIG. When the toner collection further proceeds, as shown in FIG. 7, the toner density increases at the end portion in the transport direction in the container. In this embodiment, a spiral portion is formed at the end portion in the transport direction. Therefore, a large rotational load is not applied to the spiral conveyance body 172, and it can continue to rotate with a small driving force. When the toner collection further progresses and the toner density around the spiral portion increases, as shown in FIG. 8, in the full detection device 30, the float portion 304 is floated by the collected toner 100, and the optical sensor (not shown) Is detected to be full.
[0029]
As described above, in this embodiment, the spiral portion of the spiral transport body 172 is formed on the toner collection port 25 side and not on the transport direction side. Therefore, even if the toner density on the transport direction side is increased, the spiral transport is performed. A large rotational load is not applied to the body 172.
[0030]
In this embodiment, since the spiral portion of the spiral conveyance body 172 is formed closer to the toner collection port than the projection region including the projection region of the fullness detection device 30, the toner density around the spiral portion increases. When the collected toner is deposited to such an extent that the toner is full, fullness is immediately detected by the fullness detection device 30. Therefore, the toner fullness can be detected before a large rotational load is applied to the spiral conveyance body 172.
[0031]
Furthermore, in the present embodiment, since the shielding plate 174 is provided between the full detection device 30 and the toner recovery port 25, the following effects can be obtained.
[0032]
That is, when the operator takes out the toner collection box 17 outside the apparatus and holds it in the vertical position as shown in FIG. 12 to bias the collected toner 100 toward the toner collection port 25, the shielding plate 174 is provided. Otherwise, unlike the state shown in FIG. 12, the toner collection port 25 side in the toner collection container 171 is all filled with the collected toner 100. Therefore, when the toner collection box 17 is remounted in the apparatus from this state, as shown in FIG. 13, the toner density around the spiral portion of the spiral transport body 172 increases, and a large rotational load is applied to the spiral transport body 172. I will join.
[0033]
On the other hand, since the shielding plate 174 is provided in the present embodiment, even if the toner collection box 17 is taken out of the apparatus and held in the vertical position, as shown in FIG. A space 180 is secured on the toner collection port 25 side. Therefore, even if the toner collection box 17 is remounted in this state, if the collected toner amount is relatively small, the toner density is reduced by the space 180 as shown in FIG. The rotational load applied to the carrier 172 can be reduced. If the amount of collected toner is relatively large, fullness is immediately detected by the fullness detection device 30 as shown in FIG. 15, and in any case, the rotational load applied to the spiral conveyance body 172 can be reduced. it can.
[0034]
As described above, in this embodiment, the case where the toner remaining on the intermediate transfer member and the photosensitive drum is removed has been described. However, the present invention is not limited to such an application, and the toner image is directly applied from the photosensitive drum to the recording medium. The apparatus for transferring the toner can also be applied to the recovery of the toner remaining on the photosensitive drum and the transfer roll or the transfer belt disposed opposite to the photosensitive drum.
[0035]
As is apparent from the above description, according to the present invention, it is possible to provide a toner recovery device in which the rotational load applied to the spiral conveyance body by the recovered toner is always maintained appropriately.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of a main part of an image forming apparatus including a toner recovery device to which the present invention is applied.
FIG. 2 is a cross-sectional view illustrating a main configuration of a toner recovery apparatus according to an embodiment of the present invention.
FIG. 3 is a perspective view of a float unit constituting the fullness detection device.
FIG. 4 is a first cross-sectional view illustrating a state in which toner is collected in a toner collection box.
FIG. 5 is a cross-sectional view (part 2) illustrating a state in which toner is collected in a toner collection box.
FIG. 6 is a cross-sectional view (part 3) illustrating how toner is collected in a toner collection box;
FIG. 7 is a cross-sectional view (part 4) illustrating how toner is collected in a toner collection box;
FIG. 8 is a sectional view (No. 5) showing a state in which toner is collected in a toner collection box;
FIG. 9 is a cross-sectional view showing a configuration of a conventional technique.
FIG. 10 is a cross-sectional view showing a configuration of a conventional technique.
FIG. 11 is a cross-sectional view for explaining a problem of the prior art.
FIG. 12 is a cross-sectional view for explaining the function and effect of the shielding plate.
FIG. 13 is a cross-sectional view for explaining the effect of the shielding plate.
FIG. 14 is a cross-sectional view for explaining the effect of the shielding plate.
FIG. 15 is a cross-sectional view for explaining the effect of the shielding plate.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Photosensitive drum, 4 ... Developing apparatus, 5 ... Intermediate transfer body, 10, 12 ... Transfer roll, 11 ... 1st cleaning part, 13 ... 2nd cleaning part, 14 ... 1st conveyance part, 16 ... Second transport unit, 17 ... Toner collection box, 20 ... Motor, 21 ... Third transport means, 22 ... Fourth transport means

Claims (7)

In a toner recovery apparatus for recovering toner used in an image forming apparatus and removed from the surface of an image carrier of the image forming apparatus,
A toner collection container for containing the collected toner and detachable from the image forming apparatus provided with the image carrier;
Both ends of the toner collection container are rotatably supported, and a spiral conveyance body having no spiral portion in a predetermined range from the conveyance direction side end; and
A toner recovery port that is opened only on the spiral portion side of the spiral conveyance body of the toner recovery container;
A toner recovery device comprising:   2. The toner recovery unit according to claim 1, wherein a fullness detection unit that detects whether or not the recovery toner is accumulated up to a predetermined height in its projection area is attached to an upper portion of the toner recovery container. apparatus. The full detection means is
A float part supported in a floatable state by the collected collected toner;
The toner collecting apparatus according to claim 2, further comprising a sensor unit that detects that the float unit has floated to a full position.   4. The toner recovery apparatus according to claim 2, wherein a shielding member is provided between the full detection unit and the toner recovery port.   The spiral part is not formed in the range from the conveyance direction side edge part to the projection area vicinity of the said full detection means in the said helical conveyance body, The Claim 2 thru | or 4 characterized by the above-mentioned. Toner recovery device.   6. The spiral conveyance body according to claim 2, wherein a spiral portion is formed from the projection area to the toner collection port side including the projection area of the fullness detecting means. Toner recovery device. 7. The toner collecting apparatus according to claim 1, wherein the spiral portion of the spiral conveyance body satisfies the following expression in relation to an outer diameter and a pitch.
Outer diameter x 1.2 ≤ Pitch

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