JP2007279264A - Cleaning device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner removing device capable of effectively removing even high-aggregated toner, which is not transferred but left, thereby preventing occurrence of image defects, and to provide an image forming apparatus with the toner removing device. <P>SOLUTION: Toner left on an image carrier such as a photoreceptor drum is removed by a drum cleaner, discharged to a duct 6 for discharge by a first toner extrusion screw 14, and sent in a downslope oblique pipe part 30 of a conveyance pipe from the duct 6 to be carried to a toner collection box. A second toner extrusion screw (toner conveyance member) 35 provided to the oblique pipe part 30 pushes and sends the residual toner freely falling from the duct 6. The residual toner discharged to the duct 6 is electrostatically charged intensely by the photoreceptor drum to stick on the duct 6 and then accumulate to block the duct 6. First and second wipers 51 and 52 are repeatedly engaged and disengaged as the second toner extrusion screw 35 is driven to rotate to scrape off the toner sticking on the internal wall, thereby preventing the toner from being deposited on the internal wall. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrophotographic image forming apparatus (hereinafter simply referred to as an “image forming apparatus”) such as a copying machine, a printer, a facsimile machine, and a multi-function machine that forms an image by an electrophotographic system, and an image carrier mounted on the electrophotographic image forming apparatus. The present invention relates to a cleaning device that removes and collects residual toner on the top.

  The image forming apparatus removes toner (developer) remaining on an image carrier such as an electrophotographic photosensitive drum (hereinafter simply referred to as “photosensitive drum”) or an intermediate transfer belt with mechanical force or electrostatic force. A cleaning device is provided for removal using One of the drum cleaners removes residual toner on the photosensitive drum and discharges it, and transports the toner from a discharge port of the cleaning device to a toner recovery box through a transport path (pipe) for recovery.

  By the way, in the portion where the pipe from the cleaning device and the conveyance path leading to the toner recovery container are connected, the residual toner charged with electric charges is easily clogged due to the influence of the transfer bias voltage and the like. Since this waste toner has higher cohesion than the toner to be developed, it tends to adhere to the wall surface of the pipe for sending the waste toner from the cleaning device to the waste toner pipe. Residual toner adheres to the wall surface of the pipe and grows. When the toner clogs in the conveying path, the toner overflows from the cleaning device, and the overflowing residual toner spills on the sheet as the recording material. As a result, image defects occur and peripheral devices are damaged in some cases, and many waste toner collecting devices for preventing toner clogging have been proposed (see, for example, Patent Document 1).

  With reference to FIG. 10, a conventional waste toner collecting device for eliminating waste toner clogging will be described.

  Waste toner collected from the photosensitive drum by the drum cleaner is transported to the receiving port 66 of the waste toner pipe 67 by the waste toner transport coil 62 of the drum cleaner. Waste toner in the waste toner pipe 67 is sent by the transport coil 68 and collected in a waste toner collection bag. A receiving port 62 of the waste toner pipe 67 is provided with a U-shaped vibrating piece 71 made of a flexible material having an appropriate rigidity. The drive piece 73, which is a part of the vibrating piece 71, is disposed so as to enter the inside of the waste toner carrying coil 68. When the waste toner carrying coil rotates, the vibrating piece 71 repeats the rotation with the locking piece 72 fixing the vibrating piece 71 as a fulcrum, so that the vibrating piece 71 vibrates. The shape of the vibrating piece 71 is a U shape or a B shape. The size of the vibrating piece 73 is smaller than the size of the receiving port of the waste toner pipe. In this configuration, the waste toner is prevented from adhering around the receiving port 66 of the waste toner pipe 68 due to the vibration of the vibration piece 71. Further, Patent Document 2 discloses a configuration for reducing toner adhesion using vibration as described above. In the waste toner collecting apparatus of this document, the residual toner removed from the photosensitive drum is sent to a waste toner pipe. The pipe connected to the waste toner pipe is provided with a PET film vibrating piece having appropriate flexibility and waist strength (rigidity). A structure is disclosed in which the vibrating piece is vibrated with the rotation of the coil to prevent the waste toner from adhering to the wall surface and collected in a collection box.

Japanese Patent Laid-Open No. 11-84968 JP-A-2005-070260

  However, many waste toners have a high degree of aggregation, and some waste toners may not be able to be removed as intended even if vibration is applied. That is, when the temperature in the cleaner container rises as the image forming apparatus is used, the viscosity of the waste toner also increases. Waste toner having a high degree of cohesion and increased viscosity cannot be removed even when vibration is applied, and is deposited near the inlet. Further, since these toners are outside the area of the conveying screw, they cannot be scraped with the conveying screw.

  An object of the present invention is to provide a cleaning device that prevents accumulation of toner that cannot be removed by vibrations adhering to a wall surface in the vicinity of the entrance of a conveyance path on the side where waste toner is sent.

  The cleaning device of the present invention has a cleaning member for cleaning the toner on the image carrier, a recovery container for recovering the toner cleaned by the cleaning member, and an opening and a transport member for transporting the toner. A first conveying path that conveys toner sent from the opening and a second conveying path that joins the first conveying path and sends the toner toward the first conveying path. It has a space for the toner from the second transport path to move toward the member, and has a scraping member that moves in the first transport path and scrapes the toner on the wall surface near the opening of the first transport path. Features.

  According to the present invention, it is possible to prevent toner that cannot be removed due to vibration adhering to the wall surface near the entrance of the conveyance path on the side where the waste toner is sent, from being accumulated.

  Hereinafter, a preferred embodiment of a cleaning device according to the present invention will be described in detail with reference to the drawings.

(Image forming device)
As shown in FIG. 1, the image forming unit has a charger 2 that charges the image carrier by applying a charging bias voltage to the surface of the photosensitive drum 1 that is an image carrier. It has exposure means 30 such as a laser scanner for forming an electrostatic latent image thereon. The electrostatic latent image is formed with a toner image using a developer (toner) in the developing unit. A rotary developing unit 4 that rotates on a central axis is provided as a developing unit that acts on the photosensitive drum 1. The rotary developing unit 4 includes, for example, developing units 4Y, 4M, and 4C for Y (yellow), M (magenta), and C (cyan) colors using a two-component developer composed of two components of toner and carrier. It is equally distributed radially on the same circumference. In addition, it has a developing device 4K corresponding to K (black) color, and this black developing device 4K uses a developer composed of only one component of toner. In this embodiment, the black developing device 4K is provided separately from the rotary developing unit 4. By doing so, it is possible to improve serviceability in image formation of monochrome images that are frequently used.

  Further, the endless intermediate transfer belt 50 is pressed against the photosensitive drum 1 by the primary transfer roll 10, and the toner image on the photosensitive drum is transferred onto the intermediate transfer belt 50. The toner image transferred onto the intermediate transfer belt 50 is transferred to the sheet P, which is a recording material conveyed by a conveying device (not shown), by the pressing action of the secondary transfer roll 12. The sheet P to which the toner image has been transferred is fixed by heat by a fixing means (not shown), and is discharged out of the apparatus main body to complete a series of image forming operations.

(Cleaning device)
Next, referring to FIG. 1, the cleaning device of this embodiment will be described with reference to FIG.

  The toner remaining on the photosensitive drum 1 without being transferred onto the intermediate transfer belt 50 is removed by the drum cleaner 11. A first toner extrusion screw 14 which is a conveying member provided in the drum cleaner 11 pushes the residual toner to freely drop the conduit 6 which is a second conveying path for discharging the toner directly below in the vertical direction. The residual toner that has fallen freely is sent to the inclined tube portion 30 that is the first conveying path of the portion of the conveying tube 3 that has a downward slope, and the second toner that is a conveying member incorporated in the inclined tube portion 30. It is pushed by an extrusion screw (toner conveying member) 35, conveyed from the inclined tube portion 30 through the horizontal tube portion 31, and collected in the toner collection box 17 as a collection container. When reusing it, it is sent to a recycling device (not shown).

  On the other hand, in the intermediate transfer belt 50, the toner remaining on the intermediate transfer belt 50 without being completely transferred after the secondary transfer onto the sheet P is removed by the belt cleaner 13. Residual toner is sent to the horizontal tube portion 31 by the third toner extrusion screw 21 which is a conveying member provided in the belt cleaner 13, and is conveyed to the toner collection box 17 and collected.

  Excess carrier and toner in the developing devices 4Y, 4M, and 4C of the rotary developing unit 4 are sent to a tubular toner discharge conduit 8 by a fourth toner extrusion screw 4S disposed at the unit rotation center. Residual toner falls freely through the conduit 8 and is collected from the conveyance tube 3 to the toner collection box 17.

  As apparent from FIGS. 3 to 6, the second toner extrusion screw 35 is formed of a metal material into a spiral shape having a rectangular cross section, and is composed of a shaft portion and a spiral portion joined by soldering or the like. Yes. The drive gear 5 is mounted on the shaft of the second toner extrusion screw 35, and is output from a motor (not shown) as a rotational drive source and receives rotational power to drive the second toner extrusion screw 35 to rotate. The screw is not limited to this configuration.

  Therefore, in order to prevent toner clogging, in the present embodiment, the first and second wipers (scraping members) 51 and 52 are provided in a shape capable of obtaining an elastic force such as a spring member. Both wipers are made of stainless steel wire springs, and both have wire diameters of, for example, 0.9 mm and 0.6 mm. Since rigidity is required to scrape off the toner while obtaining elasticity, the length in the moving direction is a wire diameter in this embodiment, but 0.5 mm or more is necessary. The first and second wipers 51 and 52 are locked in a locking groove portion 30a (see FIG. 6) provided in the oblique tube portion 30, and can swing freely therearound. 4 and 5 show a state in which the first and second wipers 51 and 52 are positioned at the lower and upper positions, respectively. In this embodiment, it is composed of two members, a first wiper and a second wiper. Needless to say, there is no problem even if these are configured as a single member.

  In FIG. 6, the tip 52a of the second wiper 52 is tapered. The wipers are both wire spring materials made of stainless steel, and the wire diameters are φ0.9 and φ0.6, respectively. The pipe 30 is provided with a groove 30a for locking the wiper, and the wiper is swingable about the groove 30a as a rotation center. FIG. 4 shows a state where the wipers 51 and 52 are positioned below, and FIG. 5 shows a state where the wipers 51 and 52 are positioned above. The tip end portion 52a of the second wiper 52 is tapered, and as the screw 35 rotates, the second wiper 52 is lifted, and when the tip end portion 52a of the second wiper comes off the screw 35, the second wiper 52 falls. This is the mechanism. The first wiper 51 rides on the shoulder portion 52 b of the second wiper and swings in conjunction with the vertical movement of the second wiper 52. When the 1st wiper 51 is lifted up, the front-end | tip part 51a of a 1st wiper contacts the bottom face 6a of a vertical pipe member. The first wiper 51 and the second wiper 52, which are spring members, are elastically deformed by setting dimensions and shapes so that the first wiper 51 enters the bottom surface 6a of the vertical pipe member on the design drawing. When the wipers 51 and 52 are positioned above, elastic energy (potential energy) is accumulated. When the tip 52a of the second wiper 52 is detached from the screw 35, it is instantaneously released, and an impact force is applied to the waste toner pipe 30, the waste toner screw 35, and the wipers 51, 52.

  Here, the toner growth process is shown in the reference diagram of FIG. 8 when the first and second wipers 51, 52 are not provided. Residual toner begins to adhere in the vicinity of the second toner push-out screw 35 in the toner discharge conduit 3 (reference numeral L1 in FIG. 8). That is, the residual toner discharged from the drum cleaner 11 falls and scatters onto the second toner extruding screw 35 and the conduit 3, and the scattered residual toner adheres to the inner surface of the inclined tube portion 30. Further, when the inclined tube portion 30 is provided for the sake of layout, the residual toner is carried on the spiral blade of the second toner extrusion screw 35 and conveyed. In this case, if the second toner extrusion screw 35 rotates, for example, in the clockwise direction, the tendency that residual toner adheres to the right side wall of the second toner extrusion screw 35 and grows becomes significant. When the accumulation proceeds due to the adhesion of the residual toner, a toner bridge having an arch bridge shape is eventually generated (reference numeral L2 in FIG. 8). When the toner bridge further grows and the inside of the toner discharge conduit 3 at the upper part of the second toner push-out clew 35 is completely blocked, the residual toner is accumulated as it is and is completely clogged (reference numeral L3 in FIG. 8).

  In order to prevent such clogging from occurring, in the cleaning device of this embodiment, the first wiper 51 is moved up and down in conjunction with the rotation of the second toner extruding screw 35 in the vertical direction indicated by the arrow in FIG. As a result, the residual toner does not adhere to the inner surface of the inclined tube portion 30 beyond the wiper swinging range. Further, since the second toner extrusion screw 35 is made of a spiral wire, the surface area is small, and even if the residual toner adheres to the surfaces of the first and second wipers 51 and 52, it is not largely retained. By the operation of the wiper, the toner on the inner surface of the inclined tube portion 30 near the opening can be scraped off. Therefore, there is no possibility that a toner bridge is generated on the inner side of the wiper swinging range, and toner clogging can be avoided in advance.

  That is, the first and second wipers 51 and 52 are elastically deformed to accumulate potential energy, and the energy is released instantaneously so that the impact force acts on the first and second wipers 51 and 52, etc. . Thereby, a series of toner clogging from the residual toner adhering to the accumulation and complete clogging can be effectively prevented, particularly in the toner discharge conduit 6 directly below the drum cleaner 11. In the present embodiment, the wiper configuration has a space for the toner to move so that the toner conveyed from the conduit 6 can be easily conveyed to the screw as the conveying member. Further, since the toner that easily adheres to the vicinity of the opening is more on the downstream side in the direction in which the toner is conveyed by the screw, the region where the moving range is large is configured to be on the downstream side. Of course, there is no problem even if the upstream side and the downstream side are in the same movement range.

  Further, in the second toner extrusion screw 35, when the spiral pitch of the spiral blade is as narrow as about 5 mm, for example, there is a concern that when the toner adheres to the spiral blade, the gap between the blades is closed and the toner is eventually clogged. The However, even in that case, there is an advantage that the toner attached to the spiral blade is effectively wiped off by an impact force due to instantaneous release of energy from the first and second wipers 51 and 52.

  In the present embodiment, the wiper has a wire spring configuration, but the shape is not limited to this shape, and there is no problem even if it is a leaf spring shape. In the example shown in FIG. 9, the first wiper 51A is a leaf spring material, and the second wiper 52 is a wire spring material. The first wiper 51A is made of stainless steel and has dimensions of, for example, a plate thickness of 0.25 mm and a width (width on the moving surface side in this embodiment) of 1.2 mm. Although the same effect can be obtained with the configuration of the leaf spring, the thickness is preferably 2.5 mm or less in order to maintain the elastic characteristics for scraping off the toner. The first wiper 51 of the above-described embodiment is a wire spring material having a wire diameter of 0.9 mm, but the same toner removing effect was obtained also in this embodiment. As the wire diameter increases, it becomes difficult to process a fine bent portion, but it is preferable to increase the bent shape or replace it with a leaf spring as in this embodiment.

  The cleaning device of the present invention is not limited to the above embodiment, and other embodiments, application examples, modified examples, and combinations thereof are possible as long as they do not depart from the gist of the present invention. .

  For example, in the above-described embodiment, the first and second wipers 51 and 52 are configured as the toner wiping members, but are provided in two for ease of design and manufacturing. It is not limited to it. A single wiper member can be used as long as circumstances permit, or, in the extreme, a structure in which a third wiper member is provided is also possible.

FIG. 1 is a diagram showing an image forming apparatus equipped with an embodiment of a cleaning device according to the present invention. FIG. 2 is a perspective view showing only the cleaning device of the present embodiment. FIG. 3 is a perspective view showing a main part in the cleaning device of the present embodiment. These are sectional drawings which show the time of operation | movement in the principal part. FIG. 3 is a cross-sectional view showing the same operation. FIG. 3 is a perspective view showing a wiper in the main part. FIG. 5 is a cross-sectional view taken along the line AA in FIG. 4, schematically showing the residual toner adhesion suppressing effect according to the present embodiment. FIG. 4 is a diagram schematically showing a series of clogging progress states from residual toner adhesion to accumulation and clogging as a reference diagram. The figure which shows other embodiment which made the wiper the leaf | plate spring shape. The figure of a prior art example.

Explanation of symbols

1 Photosensitive drum (image carrier)
3 Toner transport tube (toner transport member)
4 Rotary Development Unit 6,8 Toner Discharge Conduit 11 Drum Cleaner 14 First Toner Extrusion Screw 17 Toner Collection Box 35 Second Toner Extrusion Screw (Toner Conveying Member)
50 Intermediate transfer belt 51, 52 First and second wiper (scraping member)

Claims (5)

A cleaning member for cleaning the toner on the image carrier, a recovery container for recovering the toner cleaned by the cleaning member, and an opening and a transport member for transporting the toner are sent from the opening. In a cleaning device having a first conveyance path that conveys toner, and a second conveyance path that joins the first conveyance path and sends the toner toward the first conveyance path,
A scraping member that has a space for the toner from the second transport path to move from the opening toward the transport member and moves in the first transport path to scrape the toner on the wall surface near the opening of the first transport path A cleaning device comprising:   The cleaning device according to claim 1, wherein the scraping member has a linear shape from the moving direction side.   The scraping member is supported at one end side and is movable so as to rotate, and the movable side is a downstream side in the direction in which the toner is moved by the conveying member. The cleaning device according to claim 2.   The cleaning device according to claim 1, wherein the operation of the scraping member is interlocked with the operation of the conveying member.   The cleaning device according to any one of claims 1 to 4, wherein the thickness of the scraping member in the moving direction is 0.5 mm to 2.5 mm.

Images