JP2010191050A - Developer collecting device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain a latent image ghost generated due to unevenness of a charging process. <P>SOLUTION: A predetermined plus voltage is applied to a transfer roller 36 from a bias power supply 40, so that wiring connected from the bias power supply 40 to the transfer roller 36 is caused to branch, thereby connecting the bias power supply 40 (a voltage applying means) to a rotating shaft 104A of a carrying member 104. After a toner image is transferred to recording paper P, plus voltage is applied to the carrying member 104. Thus, a blade 104B of the carrying member 104 is positively charged. Therefore, the surface of a photoreceptor drum 20 is positively charged so that the photoreceptor drum 20 is subjected to static elimination. Thus, charging unevenness of the photoreceptor drum 20 is restrained to prevent a latent image ghost. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a developer recovery apparatus and an image forming apparatus.

  As a method for preventing latent image ghosts caused by unevenness in the charging process, for example, as disclosed in Patent Document 1, a light source and a charging device are provided upstream from the charging process, and static elimination is performed before the charging process. A technique for making the charging potential uniform is known.

  In Patent Document 2, a preliminary charging device is provided on the downstream side of the developing device and on the upstream side of the charging device along the rotation direction of the photosensitive drum separately from the charging device for charging the photosensitive drum.

JP 10-1333026 A Japanese Patent Laid-Open No. 11-15238

  An object of the present invention is to provide a simple developer recovery device while suppressing a latent image ghost generated due to unevenness in a charging process.

  According to the first aspect of the present invention, in the developer recovery apparatus, a voltage can be applied, and the image recovery body is rotatably provided in contact with the surface of the image support along the rotation axis of the image support. A conveying member having a groove for conveying the residual developer removed and recovered from the surface of the image bearing member in a direction along the rotation axis of the image carrier.

  According to a second aspect of the present invention, in the image forming apparatus, a charging unit that charges the surface of the image carrier, a developing unit that develops an electrostatic latent image on the image carrier, and an image on the image carrier. Transfer means for transferring the toner to a transfer member, developer removing means for removing residual developer remaining on the surface of the image carrier, and transporting the residual developer removed and collected by the developer removing means. And a developer recovery device according to item 1.

  According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, the conveying member of the developer collecting device is rotatably provided, and the rotational force of the image carrier is transmitted.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the second or third aspect, the voltage applying unit of the transfer unit is branched and connected to the conveying member.

  According to a fifth aspect of the present invention, in the image forming apparatus according to the second or third aspect, the voltage applying unit of the developing unit is branched and connected to the conveying member.

  According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the second to fifth aspects, the transport member includes a rotation shaft, a spiral blade provided around the rotation shaft, It is comprised including.

  According to a seventh aspect of the present invention, in the image forming apparatus according to any one of the second to fifth aspects, the transport member is provided around a rotation shaft and the rotation shaft, and has conductivity. And a foamed rubber roll having a spiral groove formed on the surface.

  According to an eighth aspect of the present invention, in the image forming apparatus according to the seventh aspect, the foamed rubber roll is disposed so as to obtain a predetermined biting amount with respect to the image holding member, and the biting amount with respect to the image holding member. The relationship between A and the depth B of the spiral groove is A> B.

  According to the first aspect of the present invention, the residual developer can be conveyed using the surface of the image carrier while charging or discharging the surface of the image carrier.

  According to the second aspect of the present invention, the configuration in the image forming apparatus can be simplified as compared with the case where an auxiliary charger or a static eliminator is separately provided.

  According to the third aspect of the present invention, the unevenness in the circumferential direction of charge removal or auxiliary charging of the image carrier can be eliminated, and the effect of charge removal or auxiliary charging can be further improved.

  According to the fourth aspect of the present invention, the cost can be reduced as compared with the case where the positive voltage applying means dedicated to the conveying member is provided.

  According to the fifth aspect of the present invention, the cost can be reduced as compared with the case where a negative voltage application unit dedicated to the conveying member is provided.

  According to the sixth aspect of the present invention, it is possible to obtain a strength necessary for the conveyance resistance when the residual developer is conveyed.

  According to the seventh aspect of the present invention, physical damage such as scratches caused by the conveyance member coming into contact with the image carrier is suppressed.

  According to the eighth aspect of the present invention, it is possible to eliminate the unevenness in the circumferential direction of the image carrier due to the spiral shape and to improve the effect of the charge removal or the auxiliary charge.

FIG. 2 is a schematic configuration diagram schematically illustrating a main part of an image forming apparatus including a waste toner conveying device according to an embodiment. FIG. 3 is a perspective view illustrating a waste toner conveyance device according to the embodiment. It is a perspective view showing a drive mechanism of the waste toner conveying device of the present embodiment. 2A is a plan view and FIG. 2B is a side view showing the inside of the waste toner conveying device of the present embodiment. It is a schematic diagram showing a drive mechanism of the waste toner conveying device of the present embodiment. FIG. 5 is a wiring diagram illustrating a method for applying a positive voltage to a conveyance member of the waste toner conveyance device according to the embodiment. FIG. 6 is a wiring diagram illustrating a method for applying a negative voltage to a conveyance member of the waste toner conveyance device according to the embodiment. FIG. 10 is a cross-sectional view illustrating a modified example of the conveyance member of the waste toner conveyance device according to the embodiment.

  An image forming apparatus 10 such as a copying machine or a printer using an electrophotographic system using a developer recovery apparatus according to an embodiment of the present invention will be described.

For the components arranged for each color of yellow (Y), magenta (M), cyan (C), and black (K), “Y”, “M”, “C”, “ The letter “K” is attached. However, when it is not necessary to distinguish between Y, M, C, and K, Y, M, C, and K may be omitted.
<Outline of image forming apparatus>
First, an outline of the image forming apparatus 10 will be described.

  FIG. 1 is a schematic configuration diagram illustrating a main part of the image forming apparatus 10. The image forming apparatus 10 includes photosensitive drums 20Y to 20K as image carriers. The photoconductor drums 20Y to 20K are arranged side by side in the vertical direction, and are rotated by a drive mechanism (not shown) with the rotation shafts 21Y to 21K as axes.

  The surfaces of the photosensitive drums 20Y to 20K are charged by charging rollers (charging means) 22Y to 22K. After charging, electrostatic latent images are formed on the surfaces of the photosensitive drums 20Y to 20K by laser beams LY, LM, LC, and LK emitted from an optical scanning device (not shown). The electrostatic latent images are developed by developing rolls 25Y to 25K provided in developing devices (developing units) 24Y to 24K, and toner images of respective colors are formed on the surfaces of the photosensitive drums 20Y to 20K.

  On the other hand, the conveyor belt 34 is stretched between the driving roller 31 and the driven roller 32, and the inner surface of the conveyor belt 34 is placed at a predetermined position between the driving roller 31 and the driven roller 32 in each color. Correspondingly, four transfer rollers (transfer means) 36Y to 36K are arranged. The transfer rollers 36Y to 36K are opposed to the photoconductive drums 20Y to 20Y with the conveying belt 34 interposed therebetween, and form a transfer electric field between the photoconductive drums 20Y to 20K.

  Then, the respective color toner images on the photosensitive drums 20Y to 20K of the respective colors are sequentially transferred and superimposed on the recording paper P that is sucked and conveyed by the conveying belt 34 and is superposed on the recording paper P. Toner image) is formed. The recording paper P onto which the full color toner image has been transferred is conveyed to a fixing device (not shown), and is discharged after the full color toner image has been fixed on the recording paper P.

  After the toner image is transferred to the recording paper P, the waste toner remaining on the photosensitive drums 20Y to 20K is removed by cleaning blades (developer removing means) 26Y to 26K. The cleaning blades 26Y to 26K have a plate shape whose longitudinal direction is the axial direction of the rotation shafts 21Y to 21K of the photosensitive drums 20Y to 20K, and are arranged on blade holders 28Y to 28K made of sheet metal having an L-shaped cross section. Is retained.

The waste toner removed by the cleaning blades 26Y to 26K is transported by waste toner transport devices 100Y to 100K as developer collecting devices, and stored in a separately provided replaceable waste toner storage container 38 (see FIG. 2). Is done.
<Waste toner transport device>
Here, the waste toner conveying devices (developer collecting devices) 100Y to 100K will be described. The waste toner conveying devices 100Y to 100K have the same configuration for each color, and therefore will be described without distinguishing Y, M, C, and K.

  As shown in FIGS. 3, 4 </ b> A, and 4 </ b> B, the waste toner conveyance device 100 includes a first conveyance path 102 and a second conveyance path 202. The first transport path 102 is disposed horizontally and is formed with the axial direction of the rotating shaft 21 of the photosensitive drum 20 as the longitudinal direction. A blade holder 28 (see FIG. 1) holding the cleaning blade 26 is fixed to the first conveyance path 102, and waste toner removed by the cleaning blade 26 is accommodated in the first conveyance path 102. .

  Inside the first conveyance path 102, a conveyance member 104 is disposed with the axial direction of the rotation shaft 21 of the photosensitive drum 20 as the longitudinal direction. The conveying member 104 includes a rotation shaft 104A, and spiral blades (grooves) 104B are formed around the rotation shaft 104A.

  As shown in FIG. 3, a spur gear 110 is provided at one end of the rotating shaft 104 </ b> A of the conveying member 104 (upstream side in the waste toner conveying direction (arrow K <b> 1) described later). The spur gear 110 meshes with a spur gear 112 provided at one end of the photosensitive drum 20. For this reason, the conveyance member 104 rotates when the photosensitive drum 20 rotates.

  As shown in FIG. 3 and FIG. 4A and the like, the waste toner removed by the cleaning blade 26 as the conveying member 104 rotates about the rotation shaft 104A becomes one side as indicated by an arrow K1. From the end side (upstream side) to the other end side (downstream side).

  The second transport path 202 is horizontally disposed and has a cylindrical shape whose longitudinal direction is a direction orthogonal to the axial direction of the rotation shaft 21 of the photosensitive drum 20. The second conveying path 202 is orthogonal to the longitudinal direction.

  Here, the second transport path 202 is arranged horizontally, but the second transport path 202 may be inclined with the upstream side of the second transport path 202 facing up and the downstream side facing down. Further, the longitudinal direction of the first transport path 102 and the longitudinal direction of the second transport path 202 only need to intersect each other, and are not necessarily orthogonal to each other.

  Inside the second conveyance path 202, a conveyance member 204 having a longitudinal direction in a direction orthogonal to the direction of the rotation shaft 21 of the photosensitive drum 20 is disposed (the conveyance member 104 and the conveyance member 204 are also orthogonal to each other). ) The conveying member 204 includes a rotation shaft 204A, and a spiral blade 204B is formed around the rotation shaft 204A.

  As shown in FIG. 3, a screw gear 210 is provided at one end of the rotating shaft 204A (on the upstream side in the waste toner conveyance direction (arrow K2) described later). The screw gear 210 meshes with an intermediate screw gear 214 that meshes with a screw gear 212 provided at the other end of the photosensitive drum 20. For this reason, the conveyance member 204 rotates as the photosensitive drum 20 rotates.

  Then, as the conveying member 204 rotates about the rotation shaft 204A, the waste toner is conveyed from one end side to the other end side as indicated by the arrow K2 (arrow K1 and arrow K2). Are orthogonal to each other).

  As shown in FIGS. 4A and 4B, an end portion on one side of the second transport path 202 is disposed below an end portion on the other side (downstream side) of the first transport path 102. The other end (downstream side) of the first transport path 102 and one end (upstream side) of the second transport path 202 are connected. That is, an end portion on one side (upstream side) of the second transport path 202 is disposed and connected below an end portion on the other side (downstream side) of the first transport path 102 (with the first transport path 102). It crosses three-dimensionally with the second conveyance path 202).

  An opening 152 that connects the first conveyance path 102 and the second conveyance path 204 is provided in the connection portion 150 between the first conveyance path 102 and the second conveyance path 202.

  Therefore, the waste toner that has been transported by the transport member 104 inside the first transport path 102 falls from the opening 152 and is sent to the second transport path 202 as indicated by an arrow K3 in FIG.

  As described above, the waste toner sent (dropped) to the second conveyance path 202 is rotated by the conveyance member 204 of the second conveyance path 202, so that one end side (as indicated by an arrow K2) ( It is conveyed from the upstream side to the other end side (downstream side).

  Finally, the waste toner is conveyed and stored in a waste toner storage container 38 (see FIG. 2).

  By the way, in this embodiment, the conveying member 104 is formed of a conductive member. In this case, the rotation shaft 104A and the blade 104B of the transport member 104 may be formed of the same member, or may be formed of separate members having conductivity by two-color molding or the like.

  Further, as shown in FIG. 5, since the blades 104B are in contact with the surface of the photosensitive drum 20, the hardness is made lower than that of the surface of the photosensitive drum 20, and physical damage such as scratches is caused on the surface of the photosensitive drum 20. It is necessary not to give. For this reason, it is desirable that at least the blade 104B is a conductive rubber member.

  For example, as a conductive member, a rubber material used as a base material includes general rubbers such as nitrile butadiene rubber (NBR), ethylene propylene rubber (EPM, EPDM), epichlorohydrin rubber (CO, ECO), and foams thereof. As the conductive material, a material containing carbon or an ionic conductive material is used. In addition, although the electrically conductive material mix | blended with these base materials is not specifically limited, Quaternary ammonium perchlorate etc. are generally known.

  A voltage can be applied to the conveying member 104. Specifically, as shown in FIG. 6, since a predetermined positive voltage is applied from the bias power supply 40 to the transfer roller 36, wiring connected from the bias power supply 40 to the transfer roller 36 is used. And a bias power source 40 (voltage applying means) is connected to the rotating shaft 104A of the conveying member 104.

  Then, after the toner image is transferred to the recording paper P, a plus voltage is applied to the conveying member 104. As a result, the blade 104B of the conveying member 104 is positively charged. For this reason, the surface of the photosensitive drum 20 is positively charged, and the photosensitive drum 20 is discharged. Thereby, uneven charging of the photosensitive drum 20 is suppressed and latent image ghost is suppressed.

  Here, the conveying member 104 not only conveys and collects the waste toner removed by the cleaning blade 26, but also serves as a static eliminator for the photosensitive drum 20, and therefore, compared with a case where a static eliminator is separately provided. Thus, the configuration inside the image forming apparatus 10 is simplified. In addition, the cost of the image forming apparatus 10 is reduced as compared with a case where a static eliminator is separately provided, and the image forming apparatus 10 is not required to secure a space for the static eliminator arranged around the photosensitive drum 20. Miniaturized.

  Further, as shown in FIG. 3, the spur gear 110 provided at one end of the rotation shaft 104 </ b> A of the conveying member 104 is engaged with the spur gear 112 provided at one end of the photosensitive drum 20. Yes. Thereby, the conveyance member 104 also rotates as the photosensitive drum 20 rotates. That is, a driving device for rotating the conveying member 104 is unnecessary, and the cost can be reduced accordingly.

  Here, since the conveyance member 104 conveys waste toner, it receives conveyance resistance. Therefore, a spur gear 110 that meshes with the spur gear 112 of the photosensitive drum 20 is provided on the rotation shaft 104A of the conveying member 104 so that the rotational force is transmitted from the photosensitive drum 20 via the spur gear 110. By doing so, the photosensitive drum 20 and the conveying member 104 are synchronized, and slippage is suppressed.

  In addition, the rotational force of the photosensitive drum 20 is transmitted to the conveying member 104 by the engagement of the spur gear 112 provided on the photosensitive drum 20 and the spur gear 110 provided on the conveying member 104, so The conveying member 104 rotates in the reverse direction with respect to the body drum 20. Further, by causing the blades 104B of the conveying member 104 to contact the entire surface of the photosensitive drum 20, unevenness in the circumferential direction of the static eliminating drum 20 due to the spiral shape of the blades 104B of the conveying member 104 is suppressed. Is done.

Here, the wiring from the bias power supply 40 for the transfer roller 36 is branched and connected to the rotating shaft 104A of the conveying member 104 so that the conveying member 104 is positively charged.
Since it is sufficient that a potential difference can be provided between the blade 104B of the transport member 104 and the photosensitive drum 20, the transport member 104 may be negatively charged.

  Here, as shown in FIG. 7, a predetermined negative voltage is applied to the developing roll 25 from a bias power source 42 (voltage applying means). For this reason, the wiring connected from the bias power source 42 to the developing roll 25 is branched, and the bias power source 42 is connected to the rotating shaft 104 </ b> A of the conveying member 104.

  Then, after the toner image is transferred to the recording paper P, a negative voltage is applied to the conveying member 104, whereby the surface of the photosensitive drum 20 is negatively charged. That is, in this case, the conveying member 104 also serves as an auxiliary charger for the photosensitive drum 20.

  In this embodiment, the conveying member 104 is configured by the rotating shaft 104A and the spiral blade 104B. However, it is not limited to this shape because it is sufficient that the waste toner can be conveyed. For example, as shown in FIG. 8, a conveying member 306 is used in which a spiral groove 300 is formed on the surface of a flexible foamed rubber roll 302 and the rubber roll 302 is externally fitted to a rotating shaft 304. Also good.

  Here, the rubber roll 302 is brought into pressure contact with the surface of the photoconductive drum 20 so as to obtain a predetermined biting amount A with respect to the photoconductive drum 20. Assuming that the depth of the spiral groove 300 of the rubber roll 302 is B, the relationship between the biting amount A with respect to the photosensitive drum 20 and the depth B of the spiral groove 300 is A> B (this relationship is obtained). Therefore, the rubber roll 302 is not necessarily foamed).

  Thereby, the biting part of the rubber roll 302 becomes a continuous straight line. For this reason, the biting portion between the photosensitive drum 20 and the rubber roll 302 becomes uniform, and unevenness in the circumferential direction of the static elimination or auxiliary charging photosensitive drum 20 due to the spiral shape of the conveying member 306 is eliminated, and the effect of static elimination or auxiliary charging is obtained. improves. In addition, since the spiral groove 300 is exposed except for the biting portion, a reduction in waste toner conveyance force is suppressed.

  In the above embodiment, the toner image is directly transferred from the photosensitive drum 20 to the recording paper P. However, the present invention is not limited to this. An image forming apparatus configured to transfer a toner image from a photosensitive drum to an intermediate transfer member and transfer the toner image from the intermediate transfer member to a recording sheet may be used.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 20 Photosensitive drum (image holding body)
25 Developing roll (developing means)
26 Cleaning blade (developer removal means)
36 Transfer roller (transfer means)
40 Bias power supply (voltage application means)
42 Bias power supply (voltage application means)
100 Waste toner transport device (developer recovery device)
104 Conveying member 104A Rotating shaft (Conveying member)
104B blade (conveying member)
300 Spiral groove 302 Rubber roll (foamed rubber roll, conveying member)
304 Rotating shaft (conveying member)
306 Conveying member A Amount of biting B Depth

Claims (8)

  A residual developer that can be applied with a voltage, is rotatably provided in contact with the surface of the image carrier along the rotation axis of the image carrier, and is removed from the surface of the image carrier and collected. A developer recovery apparatus having a conveying member provided with a groove portion that conveys in a direction along a rotation axis of a holder. Charging means for charging the surface of the image carrier;
Developing means for developing an electrostatic latent image on the image carrier;
Transfer means for transferring an image on the image carrier to a transfer member;
Developer removing means for removing residual developer remaining on the surface of the image carrier;
The developer recovery apparatus according to claim 1, which transports the residual developer removed and recovered by the developer removing means,
An image forming apparatus.   The image forming apparatus according to claim 2, wherein a conveying member of the developer recovery device is rotatably provided and a rotational force of the image holding member is transmitted.   The image forming apparatus according to claim 2, wherein a voltage applying unit of the transfer unit is branched and connected to the conveying member.   The image forming apparatus according to claim 2, wherein a voltage applying unit of the developing unit is branched and connected to the conveying member.   The image forming apparatus according to claim 2, wherein the conveyance member includes a rotation shaft and a spiral blade provided around the rotation shaft.   The said conveyance member is provided around the said rotating shaft, and has the electroconductivity, The foamed rubber roll by which the helical groove | channel was formed in the surface was comprised, The structure of Claims 2-5 The image forming apparatus according to claim 1.   The foam rubber roll is disposed so as to obtain a predetermined biting amount with respect to the image carrier, and a relationship between the biting amount A with respect to the image carrier and the depth B of the spiral groove is A> B. 8. The image forming apparatus according to 7.