JP2011164359A - Toner cartridge and image forming apparatus including the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner cartridge that prevents compression of toner, and to provide an image forming apparatus including the toner cartridge. <P>SOLUTION: The toner cartridge 10A includes: a toner storage part 1b; a toner conveyance part 3 including a rotary shaft 3a and a conveying blade 3c, and conveying toner stored in the toner storage part 1b in an axial direction of the rotary shaft 3a by rotating around the axial line of the rotary shaft 3a; and a toner discharge part 1c extended to the toner storage part 1b in the axial direction of the rotary shaft 3a, and provided with a toner discharge port 2 for discharging the toner conveyed by the toner conveyance part 3. The conveying blade 3c is made of elastic sponge. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a toner cartridge and an image forming apparatus including the toner cartridge.

  An electrophotographic image forming apparatus forms an image by developing with toner contained in a developing device. In the field of such an image forming apparatus, conventionally, a toner cartridge for supplying toner to a developing device is known. The toner cartridge is configured to replenish the toner contained in the toner cartridge into the developing device when the toner in the developing device is consumed and reduced due to image formation.

  For example, in Patent Document 1, a toner storage unit that stores toner, a toner discharge port, a toner discharge unit that extends to the toner storage unit, and a toner that conveys toner in the toner storage unit to the toner discharge port A toner cartridge including a transport unit is described.

JP 2006-235255 A

  According to the toner cartridge described in Patent Document 1, the toner discharge portion is surrounded by the inner wall of the toner cartridge except for the toner discharge port and the communication hole that connects the internal space of the toner storage portion and the internal space of the toner discharge portion. Therefore, the toner can be efficiently discharged from the toner discharge port. However, the toner cartridge described in Patent Document 1 has a problem because the toner discharge portion has a shape surrounded by the inner wall of the toner cartridge. That is, there is a problem that the toner transported to the inner wall of the toner cartridge without being discharged to the outside at the toner discharge port is compressed by the toner transfer unit because there is no subsequent destination. In particular, when the fluidity of the toner is lowered by being transported for a long time or left for a long time, the toner is not discharged but is frequently transported to the inner wall of the toner cartridge, and the toner is excessively compressed. When the toner is excessively compressed, the pressed toner lump adheres to the inner wall of the toner cartridge and becomes a resistance when the toner transport unit is rotationally driven. In the worst case, the toner transport unit is not rotationally driven. It will be possible.

  SUMMARY An advantage of some aspects of the invention is to provide a toner cartridge capable of suppressing toner compression and an image forming apparatus including the toner cartridge.

The present invention includes a toner container that contains toner;
A toner conveying portion provided in the toner accommodating portion, wherein the toner accommodating portion rotates around the axis of the rotating shaft, and is provided in the toner accommodating portion. A toner transport unit for transporting the contained toner in the axial direction of the rotation shaft;
A toner discharge portion extending to the toner storage portion in the axial direction of the rotation shaft, and a toner discharge portion provided with a toner discharge port for discharging the toner conveyed by the toner conveyance portion;
In the toner cartridge, at least a portion near the toner discharge port is formed of an elastic sponge.

  In the invention, it is preferable that the elastic sponge is a conductive sponge containing a conductive agent.

  In the invention, it is preferable that the elastic sponge is an open-cell sponge including open cells.

  In the invention, it is preferable that the elastic sponge is a urethane sponge formed of urethane.

  Further, the invention is characterized in that a portion formed of the elastic sponge of the conveying blade is provided so as to contact an inner wall of the toner cartridge.

The present invention also provides an electrophotographic image forming apparatus including a developing device.
An image forming apparatus comprising the toner cartridge as a toner cartridge for supplying toner to the developing device.

  According to the present invention, since the conveying blade is formed of an elastic sponge, it is possible to prevent the toner from being excessively compressed at the toner discharge portion.

  According to the present invention, since the elastic sponge is a conductive sponge, even if friction occurs between the elastic sponge and the inner wall of the toner or toner cartridge, the elastic sponge is difficult to be charged. Therefore, it is possible to suppress the elastic sponge from electrostatically adsorbing the toner.

  Further, according to the present invention, the continuous foam sponge is easily compressed or deformed as compared with the single foam sponge, and therefore, excessive compression of the toner can be suppressed.

  Further, according to the present invention, the toner cartridge can be used for a long time by using the urethane sponge having excellent wear resistance as the elastic sponge.

  Further, according to the present invention, since the portion formed of the elastic sponge of the conveying blade rotates while contacting the inner wall of the toner cartridge, the gap between the inner wall and the conveying blade is reduced, so that more toner is conveyed. be able to. Further, it is possible to reduce toner compressed by the conveying blade and the inner wall of the toner cartridge.

  According to the invention, the toner cartridge can replenish toner to the developing device stably for a long period of time. Therefore, the image forming apparatus according to the present invention can form an image stably for a long period of time.

1 is an explanatory diagram illustrating an overall configuration of an image forming apparatus 30. FIG. 2 is a cross-sectional view illustrating a configuration of a toner cartridge 10A. FIG. FIG. 3 is a cross-sectional view of the toner cartridge 10 </ b> A with AA in FIG. 2 taken along a cutting plane line. FIG. 3 is a cross-sectional view of a toner cartridge 10 </ b> A having a cutting plane line BB in FIG. 2. It is a figure for demonstrating the spiral blade surface of a 1/2 cycle. FIG. 4 is a cross-sectional view of a toner cartridge 10B corresponding to FIG. FIG. 5 is a cross-sectional view of a toner cartridge 10B corresponding to FIG. It is a figure for demonstrating the torsion blade surface of a 1/2 cycle.

  Hereinafter, the toner cartridge 10A which is the first embodiment of the toner cartridge according to the present invention and the image forming apparatus 30 which is the embodiment of the image forming apparatus according to the present invention will be described.

  First, the overall configuration of the image forming apparatus 30 will be described. FIG. 1 is an explanatory diagram showing the overall configuration of the image forming apparatus 30. As shown in FIG. 1, the image forming apparatus 30 includes a toner cartridge 10A, a photosensitive drum 17, a developing device 20, a paper feeding cassette 21, an exposure device 22, a fixing device 23, a transfer device 24, a charging device 25, and a cleaning device 26. A paper feed roller 27, a paper discharge roller 28, a paper discharge tray 29, and a scanner unit 31.

  The scanner unit 31 includes a document setting tray (not shown), an automatic reversing document feeder (RADF) (not shown), and a document reading device (not shown).

  The document setting tray is a tray for setting a document to be placed on the document placing table of the document reading apparatus. The automatic reversing document conveyance device is a device that conveys a document placed on a document set tray to a document placement table of a document reading device. The document reading device includes a document placement table, a document scanning device, a reflection member, a line sensor including a photoelectric conversion element (CCD, Charge Coupled Device), and the like, and image information of a document placed on the document placement table. Is a device that reads out every plural lines, for example, every ten lines.

  The document placing table is a glass plate-like member for placing a document on which image information is to be read. The document scanning device includes a light source (not shown) and a first reflection mirror, and reciprocates at a constant speed V in parallel along the lower surface in the vertical direction of the document placement table, thereby forming an image of the document placed on the document placement table. Irradiate the surface with light. A reflected light image is obtained by such light irradiation. The light source is a light source for irradiating the document placed on the document table. The first reflecting mirror reflects the reflected light image toward the reflecting member.

  The reflecting member includes a second reflecting mirror, a third reflecting mirror, and an optical lens (not shown), and forms a reflected light image obtained by the document scanning device on the photoelectric conversion element line sensor. The reflecting member reciprocates at a speed of V / 2 following the reciprocating movement of the document scanning device. The second reflection mirror and the third reflection mirror reflect the reflected light image obtained by the document scanning device toward the optical lens. The optical lens forms the reflected light image reflected by the second reflecting mirror and the third reflecting mirror on the photoelectric conversion element line sensor.

  The CCD line sensor includes a CCD circuit (not shown). The CCD circuit photoelectrically converts the reflected light image formed by the optical lens into an electrical signal, and outputs an electrical signal as image information to an image processing unit (not shown) of the image forming apparatus 30. The image processing unit converts image information input from an external device such as a document reading device or a personal computer into an electrical signal and outputs the electrical signal to the exposure device 22.

  The photosensitive drum 17 is a roller-like member that is supported by a drive unit (not shown) so as to be rotatable about an axis, and on which an electrostatic latent image, and thus a toner image, is formed. As the photosensitive drum 17, for example, a roller-shaped member including a conductive substrate (not shown) and a photosensitive layer formed on the surface of the conductive substrate can be used. Examples of the shape of the conductive substrate include a cylindrical shape, a columnar shape, and a sheet shape, and among them, a cylindrical shape is preferable. Examples of the photosensitive layer include an organic photosensitive layer and an inorganic photosensitive layer.

  Examples of the organic photosensitive layer include a photosensitive layer in which a charge generation layer, which is a resin layer containing a charge generation material, and a charge transport layer, which is a resin layer containing a charge transport material, and a charge generation material in one resin layer. And a single photosensitive layer containing a charge transport material. Examples of the inorganic photosensitive layer include a photosensitive layer containing one or more selected from zinc oxide, selenium, amorphous silicon and the like.

  A base film may be interposed between the conductive substrate and the photosensitive layer. Further, a surface film (protective film) for protecting the photosensitive layer may be provided on the surface of the photosensitive layer.

  The charging device 25 is a device that charges the surface of the photosensitive drum 17 and is, for example, a sawtooth charger. A power source (not shown) is connected to the charging device 25, and the charging device 25 receives a voltage from the power source to charge the surface of the photosensitive drum 17 to a predetermined polarity and potential. As the charging device 25, in addition to the saw-tooth charger, a charger charger, a charging brush charger, a roller charger, a contact charger such as a sponge, or the like can be used.

  The exposure device 22 receives image information of a document read by the scanner unit 31 or image information from an external device, and irradiates the charged surface of the photosensitive drum 17 with signal light corresponding to the image information. As a result, an electrostatic latent image corresponding to the image information is formed on the surface of the photosensitive drum 17. As the exposure device 22, for example, a laser scanning device including a light source is used. The laser scanning device is a device that combines, for example, a light source, a polygon mirror, an fθ lens, a reflection mirror, and the like. As the light source, for example, a semiconductor laser, an LED (Light Emitting Diode) array, an electroluminescence (EL) element, or the like can be used.

  The developing device 20 includes a developing tank 11, a developing roller 12, a first transport roller 13, and a second transport roller 14. The developing tank 11 stores, for example, a two-component developer composed of toner and a carrier as a developer, and rotatably supports the developing roller 12, the first conveying roller 13, and the second conveying roller 14.

  The developing roller 12 is composed of a roller-like member, and is a member that carries a developer and conveys it to the photosensitive drum 17, and is driven to rotate around an axis by a driving unit (not shown). The developing roller 12 is provided to face the photosensitive drum 17 through the opening of the developing tank 11.

  The developer carried by the developing roller 12 contacts the photosensitive drum 17 at a position where the developing roller 12 and the photosensitive drum 17 are closest to each other. This contact area is a developing nip portion, and a developing bias voltage is applied to the developing roller 12 from a power source (not shown) connected to the developing roller 12 in the developing nip portion. As a result, the toner on the surface of the developing roller 12 is supplied to the electrostatic latent image on the surface of the photosensitive drum 17.

  The first conveyance roller 13 and the second conveyance roller 14 are configured by a conveyance member such as an auger screw, for example, and are rotationally driven by a driving unit (not shown) to convey the developer stored in the developing tank 11 in opposite directions. To do.

  Further, the developing device 20 includes a toner concentration detection sensor (not shown) on the bottom surface of the developing tank 11 below the first conveying roller 13 in the vertical direction. The toner concentration detection sensor is provided such that the sensor surface is exposed inside the developing tank 11. The toner concentration detection sensor is electrically connected to a control unit (not shown). When the control unit determines that the detection result by the toner concentration detection sensor is lower than a predetermined toner concentration set value, a control signal is sent to a drive unit (not shown) that rotates and drives a toner transport unit 3 provided in a toner cartridge 10A described later. send. The toner in the toner cartridge 10 </ b> A is replenished into the developing tank 11 by the rotation of the toner transport unit 3. The toner cartridge 10A will be described in detail later.

  The transfer device 24 is composed of a roller-like member, is rotatably supported by a support unit (not shown), and is rotatably provided by a drive unit (not shown). The transfer device 24 is provided so as to be in pressure contact with the photosensitive drum 17.

  As the transfer device 24, for example, a roller-shaped member including a metal cored bar having a diameter of 8 mm to 10 mm and a conductive elastic layer formed on the surface of the metal cored bar is used. As the metal forming the metal core, stainless steel, aluminum, or the like is used. As the conductive elastic layer, a rubber material in which a conductive material such as carbon black is mixed with a rubber material such as ethylene propylene diene rubber (EPDM), foamed EPDM, or foamed urethane can be used.

  The transfer device 24 is a recording medium in which a toner image developed on the photoconductive drum 17 is conveyed from a paper feed cassette 21 described later at a pressure contact portion (transfer nip portion) between the photoconductive drum 17 and the transfer device 24. This is a member to be transferred. As the recording medium passes through the transfer nip portion, the toner image on the photosensitive drum 17 is transferred to the recording medium. The recording medium onto which the toner image has been transferred is conveyed to a fixing device 23 described later.

  Further, a power supply (not shown) is connected to the transfer device 24, and when transferring the toner image to the recording medium, a voltage having a polarity opposite to the charging polarity of the toner constituting the toner image is applied to the transfer device 24. As a result, the toner image is smoothly transferred to the recording medium.

  The cleaning device 26 is a member that cleans the surface of the photosensitive drum 17 after the toner image is transferred. The cleaning device 26 includes a cleaning blade (not shown) and a toner storage tank (not shown). The cleaning blade is composed of a plate-like member extending in parallel along the axial direction of the photosensitive drum 17, and is provided so that one end in the width direction of the plate-like member contacts the surface of the photosensitive drum 17. The cleaning blade comes into contact with the surface of the rotating photosensitive drum 17 to remove toner, paper dust, and the like remaining on the surface of the photosensitive drum 17 after transferring the toner image onto the recording medium from the surface of the photosensitive drum 17. it can. The toner storage tank is composed of a container-like member, and temporarily stores the toner removed by the cleaning blade.

  The paper feed cassette 21 is a tray that stores recording media such as plain paper, coated paper, color copy paper, and OHP film.

  The paper feed roller 27 is a pair of rollers provided between the paper feed cassette 21 and the transfer nip portion, and conveys the recording medium stored in the paper feed cassette 21 one by one toward the fixing nip portion. The paper feed roller 27 performs recording so that the timing when the predetermined position of the toner image on the photosensitive drum 17 is conveyed to the transfer nip portion coincides with the timing when the predetermined position of the recording medium is conveyed to the transfer nip portion. Transport the media.

  The fixing device 23 is a member that heats, melts, and fixes the toner constituting the unfixed toner image carried on the recording medium conveyed from the transfer nip portion to the recording medium. The fixing device 23 includes a fixing roller 32 and a pressure roller 33. The fixing roller 32 is a roller-like member that is rotatably supported by a support unit (not shown), and is provided to be rotatable around an axis line by a drive unit (not shown). The fixing roller 32 is composed of, for example, a roller-shaped member including a cored bar and an elastic layer formed on the surface of the cored bar. The core metal is formed of a metal such as iron, stainless steel, or aluminum. The elastic layer is formed of an elastic material such as silicone rubber or fluorine rubber, for example.

  The fixing roller 32 has a heating unit (not shown) therein. The heating unit generates heat when a voltage is applied from a power source (not shown). For example, a halogen lamp or an infrared lamp can be used as the heating unit.

  The pressure roller 33 is a roller-like member that is rotatably supported by a support portion (not shown), and is provided so as to be in pressure contact with the fixing roller 32 by a pressure portion (not shown). The pressure roller 33 is configured to rotate following the rotation of the fixing roller 32. A pressure contact portion between the fixing roller 32 and the pressure roller 33 is referred to as a fixing nip portion.

  The pressure roller 33 promotes fixing of the toner image on the recording medium by pressing the recording medium toward the toner in a molten state by the fixing roller 32. As the pressure roller 33, a roller-like member having the same configuration as that of the fixing roller 32 can be used. Further, a heating unit similar to the fixing roller 32 may be provided inside the pressure roller 33.

  According to such a fixing device 23, when the recording medium onto which the toner image is transferred passes through the fixing nip portion, the toner constituting the toner image is melted and the toner image is fixed on the recording medium. The recording medium on which the toner image is fixed is conveyed toward the paper discharge roller 28.

  The paper discharge roller 28 is a pair of rollers provided between the fixing nip portion and the paper discharge tray 29, and conveys the recording medium on which the toner image is fixed at the fixing nip portion toward the paper discharge tray 29. The paper discharge tray 29 is a tray on which the recording medium on which the toner image is fixed is placed face down.

  Next, the toner cartridge 10A will be described in detail. FIG. 2 is a cross-sectional view illustrating the configuration of the toner cartridge 10A, and corresponds to a front view when the front wall portion of the toner cartridge 10A is removed. FIG. 3 is a cross-sectional view of the toner cartridge 10A taken along line AA in FIG. 2, and corresponds to a plan view when the upper wall portion of the toner cartridge 10A is removed. FIG. 4 is a cross-sectional view of the toner cartridge 10A taken along line BB in FIG. 2 and corresponds to a right side view when the right side wall portion of the toner cartridge 10A is removed. The toner cartridge 10 </ b> A includes a toner container 1, a toner transport unit 3, and a toner scooping unit 8, and replenishes toner to the developing device 20.

  The toner storage container 1 includes a toner storage unit 1a, a toner storage unit 1b, and a toner discharge unit 1c. The toner storage unit 1a has a substantially semi-cylindrical internal space, stores toner in the internal space, and rotatably supports the toner pumping unit 8.

  The toner pumping unit 8 rotates to supply the toner stored in the toner storage unit 1a to the toner storage unit 1b. The toner pumping unit 8 is integrally provided with a rotating shaft 8a, a pumping gear 8b, a pumping plate 8c, and a pumping blade 8d, and from a driving motor and a gear transmission mechanism (not shown) via the pumping gear 8b. It is comprised so that it may rotate centering on the rotating shaft 8a with the driving force of.

  The rotating shaft 8a is a columnar member provided along the axial direction of the toner storage unit 1a, and a pumping gear 8b is provided at one end in the axial direction. The pumping plate 8c is a rectangular plate-like member, and a through-hole penetrating in the longitudinal direction is provided at the center in the width direction. The rotary shaft 8a is inserted and fixed in the through hole of the pumping plate 8c. The pumping blade 8d is made of a flexible polyethylene terephthalate (PET) sheet having a thickness of about 0.5 mm to 2 mm, and is provided at both ends in the width direction of the pumping plate 8c.

  According to the toner pumping unit 8, the pumping plate 8c and the pumping blade 8d rotate with the rotation of the rotating shaft 8a, whereby the toner in the toner storage unit 1a is pumped up to the toner storage unit 1b. At this time, the pumping blade 8d rotates while deforming while being in sliding contact with the inner wall of the toner storage unit 1a due to its flexibility, and pumps the toner on the downstream side in the rotation direction.

  The toner container 1 is provided with a partition wall 4 made of a plate-like member along the axial direction of the toner storage portion 1a. The partition wall 4 has a function of holding an appropriate amount of toner pumped up by the toner pumping unit 8 in the toner container 1b.

  The toner storage portion 1b is provided along the toner storage portion 1a with the partition wall 4 interposed therebetween. The toner storage unit 1b has a substantially semi-cylindrical internal space smaller than the internal space of the toner storage unit 1a. The toner transport unit 3 is rotatably supported in the internal space. Accommodates the supplied toner. The toner transport unit 3 is provided to transport the toner stored in the toner storage unit 1b in the transport direction C, which is one of the axial directions of the toner transport unit 3. The toner transport unit 3 will be described later.

  The toner discharge portion 1c has a substantially semi-cylindrical internal space, and extends to the toner storage portion 1b downstream in the conveyance direction C of the toner storage portion 1b. The toner discharge portion 1c is provided so that the internal space of the toner storage portion 1b communicates with the internal space of the toner discharge portion 1c. The toner discharge unit 1 c is provided with a toner discharge port 2 for supplying the toner to the developing device 20 by discharging the toner conveyed by the toner conveyance unit 3. The toner discharge port 2 and a toner supply port (not shown) of the developing device 20 are connected directly or via a pipe (not shown) so that the toner discharged from the toner discharge port 2 is supplied to the developing device 20. become. In the present embodiment, the toner discharge port 2 is a substantially rectangular opening provided on the lower surface in the vertical direction of the toner discharge portion 1c.

  As described above, the toner transported to the toner discharge portion 1c by the toner transport portion 3 is discharged to the outside of the toner cartridge 10A at the toner discharge port 2. In the toner cartridge 10A, the toner discharge portion 1c is surrounded by the inner wall of the toner cartridge 10A except for the toner discharge port 2 and a communication hole that connects the internal space of the toner storage portion 1b and the internal space of the toner discharge portion 1c. Yes. Therefore, the toner can be efficiently discharged from the toner discharge port 2. Further, in the toner cartridge 10A, since the toner discharge port 2 is provided in the toner discharge portion 1c instead of the toner containing portion 1b, the toner pumped up by the toner pumping portion 8 can be prevented from flowing into the developing device 20 at a stretch. Therefore, an appropriate amount of toner can be supplied.

  Next, the toner transport unit 3 will be described. The toner transport unit 3 includes a rotation shaft 3a, a transport gear 3b, and a transport blade 3c, and transports the toner in the toner storage unit 1b in the transport direction C by rotating around the axis of the rotation shaft 3a. The rotating shaft 3a and the conveyance gear 3b are formed from materials such as polyethylene, polypropylene, high impact polystyrene, and ABS resin (acrylonitrile-butadiene-styrene copolymer synthetic resin).

  The rotary shaft 3a is a cylindrical member having a radius of 2 mm to 5 mm, and is provided from the end of the toner containing portion 1b to the end of the toner discharging portion 1c along the axial direction of the toner containing portion 1b. A conveyance gear 3b is provided at the downstream end of the rotation shaft 3a in the conveyance direction C. The rotating shaft 3a is configured to rotate at 60 rpm to 200 rpm by a driving force from a driving motor and a gear transmission mechanism (not shown) via the transport gear 3b.

  The conveying blade 3c is provided around the rotating shaft 3a. The transport blade 3c is a member that transports the toner in the toner storage portion 1b in the transport direction C by rotating with the rotation of the rotary shaft 3a.

  First, a conventional conveying blade will be described. Conventional conveying blades are molded from a highly rigid resin or the like. Similarly to the transport blade 3c of the present embodiment, the conventional transport blade also discharges the toner from the toner discharge port 2 by transporting the toner in the transport direction C. The toner transported to the transport blades is discharged from the toner discharge port 2 in order from the lower one in the vertical direction. Here, generally, toner tends to decrease in fluidity when it is transported or left for a long period of time. When the toner fluidity is lowered, even if the toner in the lower vertical direction is discharged, the toner in the upper vertical direction is not discharged but is transported to the inner wall on the downstream side in the transport direction C of the toner cartridge 10A. There is. In such a case, since the conventional conveying blade has high rigidity, the toner is excessively compressed and compressed by the conveying blade and the inner wall of the toner cartridge 10A. If the toner is pressed and hardened, the conveying blade may not be able to rotate.

On the other hand, in this embodiment, the conveyance blades 3c are all made of an elastic sponge. The elastic sponge is a sponge having a minimum rigidity necessary for transporting the toner, and the toner sandwiched between the inner wall of the toner cartridge 10A and the transport blade 3c without being discharged at the toner discharge port 2 is excessively compressed. In other words, the sponge is elastic so that the conveying blade 3c is compressed or deformed. Specifically, the elastic sponge is, for example, a material having a compression deformation rate of 50% or more and 80% or less. Here, the compressive deformation rate is the minimum value of the thickness of the sample when a load of 0.1 N / cm ² per ^second is applied in the thickness direction to a cubic sample having a side of 1 cm as F [cm]. Is given by the following formula (1).
Compression deformation rate [%] = (1−F) × 100 [%] (1)

  Since the conveyance blade 3c of the present embodiment is made of such an elastic sponge, it is possible to prevent the toner from being excessively compressed by the toner discharge portion 1c. As a result, the toner can be replenished to the developing device 20 stably for a long period of time. Therefore, the image forming apparatus 30 can form an image stably for a long period of time.

Each opening of the elastic sponge is preferably sized so that toner does not enter the opening. Specifically, for example, the opening area is 1 μm ² or more and 10 μm ² or less. Moreover, when expressed by the opening diameter, for example, it is 1 μm or more and 3 μm or less. By providing the opening having such a size, the friction between the toner and the elastic sponge can be increased while suppressing the toner from entering the opening. This makes it easier for the toner to rotate with the conveying blade 3c. Accordingly, the toner in the vertical direction that has not been discharged from the toner discharge port 2 due to the decrease in fluidity can be moved downward in the vertical direction, and can be easily discharged from the toner discharge port 2.

  As the elastic sponge, urethane sponge, rubber sponge, polyethylene sponge and the like can be used, and among them, urethane sponge having excellent abrasion resistance is preferable. By using urethane sponge as the elastic sponge, the toner cartridge 10A can be used for a long time. The elastic sponge is preferably an open-cell sponge having open cells. Since the open-cell sponge is easily compressed or deformed as compared with the single-cell sponge, excessive compression of the toner can be suppressed. Open-cell sponge is, for example, a method in which a material in which fine powder of calcium carbonate is kneaded is injection-molded, and then the molded product is immersed in hydrochloric acid water to decompose and elute powdered calcium carbonate, or a water-soluble salt is kneaded. After molding, it can be obtained by a method such as elution of salt in water to form a continuous foam, or a method of adding a foaming agent in advance to the resin and physically breaking the cell walls after foam molding.

  Further, the elastic sponge is preferably a conductive sponge containing a conductive agent such as carbon black. Since the conductive sponge is difficult to be charged even if friction occurs with the toner or the inner wall of the toner cartridge 10A, electrostatic adsorption of the toner can be suppressed.

In the present embodiment, the conveying blade 3c is a spiral blade of a series, the first imaginary spiral (not shown) surrounding the outer periphery of the rotating shaft 3a advances in the axial direction of the rotary shaft 3a at a predetermined lead angle theta _X It is provided along. Here, the “lead angle” in a spiral is a tangent at an arbitrary point on the spiral and a straight line obtained by projecting the tangent to a plane perpendicular to the axial direction of a virtual cylinder surrounding the spiral. It is an angle to make. The lead angle is an angle larger than 0 ° and smaller than 90 °. The lead angle theta _X, for example can be appropriately set within a range of 20 ° to 70 °.

In the present invention, the term “spiral blade” generally refers to a blade portion of a so-called auger screw, and more specifically, a member having a spiral blade surface as a main surface. In the present invention, the “spiral blade surface” refers to one spiral C ₁ (with a lead angle θ ₁ ) surrounding the side surface of the virtual cylinder K ₁ (radius is r ₁ ). a line segment L _1, while keeping the length m _1, and the mounting angle α line segment L ₁ in the radial direction of the virtual cylinder K _1, is moved in parallel direction D to the axis of the virtual cylinder K ₁ when a plane formed trajectory of the line segment L _1. The "attachment angle α", in a plane containing the axis and the line segment L ₁ of the virtual cylinder K _1, a line segment L _1, the direction D from the contact point between the line segment L ₁ and the virtual cylinder K ₁ An angle formed by the extending half line and an angle greater than 0 ° and less than 180 °.

Hereinafter, as an example of the spiral blade surface, the spiral blade surface when the line segment is moved along the half-cycle portion of the spiral (referred to as “half-cycle spiral blade surface”). The same applies to the period of. FIG. 5 is a diagram for explaining a spiral blade surface having a half cycle. 5 (a) is a side surface of the virtual cylinder K _1, and virtual spiral C ₁ on the side of the cylinder K _1, the start position and end of the line segment L ₁ that moves on the spiral C ₁ in one direction D And position. 5 line L ₁ shown on the left side on the paper of (a) indicates the start position during movement, the line segment L ₁ shown on the right side indicates the end position. As shown in FIG. 5 (a), the length m ₁ of the segment L ₁ in the radial direction of the virtual cylinder K _1, the attachment angle alpha while keeping constant the (In FIG. 5 α = 90 °), spirals in one direction D along the C _1, when moving the segment _{L 1,} the trajectory of the line segment _{L 1} becomes spiral blade surface _{n 1} shown in Figure 5 (b). Surface indicated by the hatched portion in FIG. 5 (b) is a spiral blade surface n _1.

As shown in FIG. 5B, the outer peripheral portion of the spiral blade surface n ₁ is along a spiral C ₂ (lead angle is θ ₂ ) surrounding the virtual cylinder K ₂ whose axis coincides with the virtual cylinder K _1. . Radius _{R 1} of the virtual cylinder _{K 2} is the radius _{r 1} of the virtual cylinder _{K 1,} and the length _{m 1} of the segment _{L 1} in the radial direction of the virtual cylinder _{K 1,} equal to the sum of. A rectangular t ₁ obtained by developing the side surface of the virtual cylinder K _1, showing the rectangular t ₂ when the expansion of the side surface of the virtual cylinder K ₂ in FIG. 5 (c). As shown in FIG. 5 (c), the line corresponding to the spiral _C 1, _{C 2} in the rectangular _t 1, _{t 2} is the line _q 1, _{q 2} extending obliquely in each rectangle _t 1, _{t 2} Become. The two segments q _1, q _2, respectively, it corresponds to the spiral C ₂ along the spiral C ₁ and the outer peripheral portion along the inner peripheral portion of one cycle of the spiral blade surface n ₁ half, rectangular t _In the horizontal direction X ₁ of ₁ and t ₂ , the lengths of the _two line segments q ₁ and q ₂ are half the lengths of the horizontal sides of the rectangles t ₁ and t ₂ , respectively. Further, as shown in FIG. 5C, since the lengths of the spirals C ₁ and C _{2 in} the one direction D are equal, the two line segments q ₁ in the longitudinal direction Y ₁ of the rectangles t ₁ and t _2. , Q ₂ are equal in length. Therefore, when the toner transport unit having the spiral blade surface on the downstream side in the transport direction C is rotated around the axis, the lengths of the _two line segments q ₁ and q ₂ are equal in the longitudinal direction Y ₁ . The toner transport speed on the outer peripheral side and the toner transport speed on the inner peripheral side are substantially the same.

The angles formed by the two line segments q ₁ and q ₂ and the sides of the rectangles t ₁ and t ₂ are lead angles θ ₁ and θ ₂ , respectively. When the length L _{Y1 of the two} line segments q ₁ and q ₂ in the longitudinal direction Y ₁ is expressed using θ ₁ and θ ₂ , L _Y1 = π · r ₁ · tan θ ₁ = π · R ₁ · tan θ ₂ (Wherein π represents the circular ratio). Further, when θ ₂ is expressed by θ ₁ , θ ₂ = tan ⁻¹ (r ₁ · tan θ ₁ / R ₁ ).

When used as a conveying blade 3c as in the present embodiment, the spiral blade, the virtual radius r ₁ of the cylinder K ₁ is equal to the radius r of the rotating shaft 3a, and the lead angle theta ₁ of helix C ₁ is the first virtual configured to be equal to the lead angle theta _X of spiral. Furthermore, spiral blade, spiral blade surface becomes the conveying direction C downstream and spirals C ₁ along the inner periphery of the spiral blade is provided to match the first imaginary spiral. As long as it is configured in this way, the spiral blade may have any shape. For example, the attachment angle α does not have to be 90 °, and can be appropriately set within a range of 30 ° to 150 °. Further, the lead angle θ ₁ can be appropriately set within a range of 20 ° to 70 °, for example. In addition, the length m ₁ of the line segment L ₁ in the radial direction of the virtual cylinder K ₁ , that is, the length of the spiral blade in the radial direction can be set as appropriate within a range of 2 mm to 20 mm, for example.

  In this embodiment, the conveyance blade 3c is a spiral blade having a spiral blade surface of eight cycles, and the length of the spiral blade in the conveyance direction C, that is, the thickness of the spiral blade is uniform at 1.2 mm. . In the present embodiment, the conveying blade 3c is configured such that seven of the eight cycles are present in the toner accommodating portion 1b and one cycle is present in the toner discharging portion 1c. The period and thickness of the spiral blade can be appropriately set according to the toner conveyance speed, the size of the toner cartridge 10A, and the like. For example, the thickness of the spiral blade used as the transport blade 3c can be set as appropriate within a range of 0.5 to 3 mm.

  Next, a toner cartridge 10B that is a second embodiment of the toner cartridge according to the present invention will be described. A front sectional view of the toner cartridge 10B is the same as that shown in FIG. FIG. 6 is a cross-sectional view of the toner cartridge 10B corresponding to FIG. FIG. 7 is a cross-sectional view of the toner cartridge 10B corresponding to FIG. The toner cartridge 10 </ b> B includes a toner container 1, a toner transport unit 9, and a toner scooping unit 8, and replenishes toner to the developing device 20. The toner cartridge 10B is configured in the same manner as the toner cartridge 10A except that the toner cartridge 10B is provided with a toner transport unit 9 instead of the toner transport unit 3, and thus the description other than the toner transport unit 9 is omitted.

  The toner transport unit 9 includes a rotation shaft 9a, a transport gear 9b, and a transport blade 9c, and transports the toner in the toner storage unit 1b in the transport direction C by rotating around the axis of the rotation shaft 9a. The rotating shaft 9a and the conveyance gear 9b are formed from materials such as polyethylene, polypropylene, high impact polystyrene, and ABS resin (acrylonitrile-butadiene-styrene copolymer synthetic resin).

  The rotating shaft 9a is a cylindrical member having a radius of 2 mm to 5 mm, and is provided from the end of the toner containing portion 1b to the end of the toner discharging portion 1c along the axial direction of the toner containing portion 1b. A transport gear 9b is provided at the downstream end of the rotation shaft 9a in the transport direction C. The rotating shaft 9a is configured to rotate at 60 rpm to 200 rpm by a driving force from a driving motor and a gear transmission mechanism (not shown) via the transport gear 9b.

  The conveying blade 9c is provided around the rotating shaft 9a. In the present embodiment, the conveying blade 9c includes a sponge portion 9ca made of the elastic sponge and a non-sponge portion 9cb made of resin, ceramics, metal, or the like. The sponge portion 9ca is provided at least in the vicinity of the toner discharge port 2 in the conveying blade 9c. Specifically, for example, in the region from the downstream end portion in the transport direction C of the toner discharge portion 1c to the edge on the upstream side in the transport direction C of the toner discharge port 2, the transport blade 9c is composed of a sponge portion 9ca.

  The conveying blade 9c of the present embodiment is configured such that the non-sponge part 9cb exists in the toner storage part 1b and the sponge part 9ca exists in the toner discharge part 1c. As described above, in this embodiment, unlike the first embodiment, only a part of the conveying blade 9c is formed of the elastic sponge, but at least a portion near the toner discharge port 2 of the conveying blade 9c is elastic. Since the sponge portion 9ca is made of a sponge, it is possible to suppress the toner from being excessively compressed as in the first embodiment.

  Further, in the present embodiment, unlike the first embodiment, a portion made of an elastic sponge, that is, a sponge portion 9ca in the conveying blade 9c is provided so as to be in contact with the inner wall of the toner cartridge 10B. Since the sponge portion 9ca rotates while contacting the inner wall of the toner cartridge 10B, the gap between the inner wall and the conveying blade 9c is reduced, so that more toner can be conveyed. Further, the amount of toner compressed by the conveying blade 9c and the inner wall of the toner cartridge 10B can be reduced. Since the sponge portion 9ca can be compressed or deformed, there is little risk of damage even if friction occurs with the inner wall of the toner cartridge 10B. On the other hand, if the conventional highly rigid conveying blade is provided in contact with the inner wall of the toner cartridge 10B, the conveying blade and the inner wall of the toner cartridge 10B may be damaged by friction.

Further, in the present embodiment, the non sponges 9cb of conveying blade 9c is bout a helical blade, not shown, surrounds the outer periphery of the rotary shaft 9a proceeds in the axial direction of the rotary shaft 9a at a predetermined lead angle theta _X It is provided along the first virtual spiral. The sponge portion 9ca of the conveying blade 9c is a torsion blade, and is provided along the first virtual spiral, and its outer peripheral portion is provided along a second virtual spiral (not shown). The outer peripheral portion of the sponge portion 9ca is a portion that is the most distant from the rotation shaft 9a in the sponge portion 9ca. And the second imaginary spiral, surrounding the imaginary cylinder rotation axis 9a and the axis coincides with a spiral that advances in the axial direction of the rotary shaft 9a at a predetermined lead angle theta _Y, the second imaginary spiral When the radius of the surrounding virtual cylinder is R (> r), the spiral satisfies the following formula (2).
0 [°] <θ _Y [°] <tan ⁻¹ (r · tan θ _X / R) [°] <90 [°] (2)

Here, the lead angle θ _X of the first virtual spiral can be set as appropriate within a range of 20 ° to 70 °, for example, and the lead angle θ _Y of the second virtual spiral is within a range of 0 ° to 60 °, for example. Can be set as appropriate.

In the present invention, the “twisted blade” is a member roughly shaped like the spiral blade is twisted, and more specifically, a member having a torsion blade surface as a main surface. In the present invention, the term "twist blade surface", along one spiral C ₁ surrounding the upper surface of the virtual cylinder K _{1 (the} lead angle and theta _1), one of the line segments L _2, virtual cylinder while keeping the length of the line segment L ₂ in the radial direction of the K _1, the mounting angle while continuously changing so as to increase at a constant rate of beta, axis direction parallel to the D virtual cylinder K ₁ when moving, the locus of the line segment L ₂ is a plane formed by the. The "attachment angle β", in a plane containing the axis and the line segment L ₂ of the virtual cylinder K _1, a line segment L _2, in one direction D from the contact point of the line segment L ₂ and the virtual cylinder K ₁ An angle formed by the extending half line and an angle greater than 0 ° and less than 180 °.

Hereinafter, as an example of the torsion blade surface, it is expressed as a torsion blade surface when the line segment is moved along a half-cycle portion of the spiral (“twist cycle blade surface”). The same applies to the period of. FIG. 8 is a diagram for explaining a torsional blade surface having a half cycle. 8 (a) is a side surface of the virtual cylinder K _1, and virtual spiral C ₁ on the side of the cylinder K _1, the start position and end of the line segment L ₂ moving on spiral C ₁ in one direction D And position. Line segment L ₂ shown on the left side in the plane of FIG. 8 (a) shows the starting position for the movement, the line segment L ₂ shown on the right side indicates the end position. As shown in FIG. 8A, while maintaining the length m ₁ of the line segment L ₂ in the radial direction of the virtual cylinder K ₁ , the attachment angle β is continuously changed to increase at a constant rate. (in FIG. 8, beta = 60 ° at the starting position, beta = 120 ° at the end position), the direction D along the spiral _{C 1,} when moving a line segment _{L 2,} the locus of the line segment _{L 2} Is the torsional blade surface n ₂ shown in FIG. Surface indicated by the hatched portion in FIG. 8 (b) is a torsion blade surface n _2.

As shown in FIG. 8B, the outer peripheral portion of the torsional blade surface n ₂ is along a spiral C ₃ (lead angle is θ ₃ ) surrounding the virtual cylinder K ₂ whose axis coincides with the virtual cylinder K _1. . Radius _{R 1} of the virtual cylinder _{K 2} is the radius _{r 1} of the virtual cylinder _{K 1,} and the length _{m 1} of the segment _{L 2} in the radial direction of the virtual cylinder _{K 1,} equal to the sum of. FIG. 8C shows a rectangle t ₁ in which the side surface of the virtual cylinder K ₁ is expanded and a rectangle t ₃ in which the side surface of the virtual cylinder K ₂ is expanded. As shown in FIG. 8 (c), the line corresponding to the spiral _C 1, _{C 3} in the rectangular _t 1, _{t 3} is the line segment _q 1, _{q 3} extending obliquely in each rectangle _t 1, _{t 3} Become. The two line segments q ₁ and q ₃ correspond to the spiral C ₁ along the inner peripheral portion and the spiral C ₃ along the outer peripheral portion of the torsional blade surface n _{2 having} a half cycle, respectively. in _1, the horizontal direction _{X 1} of _{t 3,} the length of the two segments _q 1, _{q 3} is half of the length of each side of the rectangle _t 1, _{t 3} sides. Further, as shown in FIG. 8 (c), due to the mounting angle β increases in end position, the length in one direction D of the spiral C ₁ has a length in one direction D of the spiral C ₃ Therefore, in the longitudinal direction Y ₁ of the rectangles t ₁ and t ₃ , the line segment q ₁ corresponding to the spiral C ₁ is longer than the line segment q ₃ corresponding to the spiral C ₃ . Thus, when rotating the toner conveying portion having a torsion blade surface in the conveyance direction C the downstream side around the axis, the direction of the line segment q ₃ corresponding to the spiral C ₃ in the longitudinal direction Y ₁ is short, the toner The toner transport speed on the outer peripheral side is slower than the toner transport speed on the inner peripheral side of the transport unit.

The angles formed by the two line segments q ₁ and q ₃ and the sides of the rectangles t ₁ and t ₃ are the lead angles θ ₁ and θ ₃ , respectively. The longitudinal direction _Y length _{L Y1} of the segment _{q 1} in _1, expressed using _{θ 1, L Y1 = π ·} r 1 · tanθ 1 ( wherein, [pi represents the circular constant) become. Further, if the length L _Y2 of the line segment q ₃ in the longitudinal direction Y ₁ is expressed by using θ ₃ , L _Y2 = π · R ₁ · tan θ ₃ (wherein π represents the circumference). . As described above, since L _Y1 > L _Y2 , θ ₃ <tan ⁻¹ (r ₁ · tan θ ₁ / R ₁ ). From this, the toner conveying portion having the torsional blade surface on the downstream side in the conveying direction C is θ ₃ <tan ⁻¹ (r ₁ · tan θ ₁ / R ₁ ), and therefore on the inner peripheral side of the toner conveying portion. It can be seen that the toner transport speed on the outer peripheral side is slower than the toner transport speed.

When used as a sponge portion 9ca as in this embodiment, the torsion blades, virtual radius r ₁ of the cylinder K ₁ is equal to the radius r of the rotary shaft 9a, and the lead angle theta ₁ of helix C ₁ is the first virtual configured to be equal to the lead angle theta _X of spiral. Moreover, twisting vanes torsional blade surface becomes the conveying direction C downstream and spirals C ₁ along the inner periphery of the torsion blade is provided to match the first imaginary spiral. Further, in the torsion blade, the lead angle θ ₃ of the spiral C ₃ along the outer peripheral portion of the twist blade is equal to the lead angle θ _Y of the second virtual spiral, and the spiral C ₃ is the second virtual spiral. It is provided so as to match.

As described above, the present embodiment is configured to satisfy θ _Y <tan ⁻¹ (r · tan θ _X / R) by providing a twisted blade as the sponge portion 9ca. As a result, the toner transport speed is fast on the inner peripheral side of the toner transport unit 9 and slow on the outer peripheral side. Therefore, the toner in the vertical direction above the toner in the vertical direction lower than the toner in the vertical direction, proceeds in the transport direction C and is discharged from the toner discharge port 2. Thereby, in the present embodiment, the toner can be discharged more efficiently, and the toner can be prevented from being excessively compressed.

As long as it is configured as described above, the twisted blade may have any shape. The attachment angle β at the start position does not need to be 60 °, and can be appropriately set within a range of 20 ° to 150 °, for example. Further, the attachment angle β at the end position does not need to be 120 °, and can be appropriately set within a range of 40 ° to 170 °, for example. Further, the lead angle θ ₁ can be set as appropriate within a range of 20 ° to 70 °, for example, and the lead angle θ ₃ can be set as appropriate within a range of 0 ° to 60 °, for example. Further, the length m ₁ of the line segment L ₂ in the radial direction of the virtual cylinder K ₁ , that is, the length m ₁ of the torsion blade in the radial direction can be appropriately set within a range of 2 mm to 20 mm, for example.

  In the present embodiment, the non-sponge portion 9cb is a spiral blade having a 14-cycle spiral blade surface, and the length of the spiral blade in the conveyance direction C, that is, the thickness of the spiral blade is 1.2 mm and uniform. is there. Moreover, the sponge part 9ca of this embodiment is provided with two continuous torsion blades having a torsion blade surface having a half cycle. The two torsion blades have the same shape, and the length of the torsion blades in the conveyance direction C, that is, the thickness of the torsion blades is uniform at 1.2 mm. The period and thickness of the spiral blade, and the period, number of installations, and thickness of the torsion blade can be appropriately set according to the toner conveyance speed, the size of the toner cartridge 10B, and the like. For example, the thickness of the spiral blade used as the non-sponge portion 9cb can be set as appropriate within a range of 0.5 to 3 mm, and the thickness of the torsion blade used as the sponge portion 9ca is 0.5 to 3 mm. It can be set as appropriate within the range.

DESCRIPTION OF SYMBOLS 1 Toner container 1a Toner storage part 1b Toner storage part 1c Toner discharge part 2 Toner discharge port 3 Toner conveyance part 3a, 9a Rotating shaft 3b, 9b Conveying gear 3c, 9c Conveyance blade 9ca Sponge part 9cb Non-sponge part 10A, 10B Toner Cartridge 20 Developing device 30 Image forming device

Claims (6)

A toner container for containing toner;
A toner conveying portion provided in the toner accommodating portion, wherein the toner accommodating portion rotates around the axis of the rotating shaft, and is provided in the toner accommodating portion. A toner transport unit for transporting the contained toner in the axial direction of the rotation shaft;
A toner discharge portion extending to the toner storage portion in the axial direction of the rotation shaft, and a toner discharge portion provided with a toner discharge port for discharging the toner conveyed by the toner conveyance portion;
The toner cartridge according to claim 1, wherein at least a portion in the vicinity of the toner discharge port is formed of an elastic sponge.   The toner cartridge according to claim 1, wherein the elastic sponge is a conductive sponge containing a conductive agent.   The toner cartridge according to claim 1, wherein the elastic sponge is an open-cell sponge including open cells.   The toner cartridge according to claim 1, wherein the elastic sponge is a urethane sponge formed of urethane.   The toner cartridge according to claim 1, wherein a portion formed of the elastic sponge of the conveying blade is provided so as to contact an inner wall of the toner cartridge. In an electrophotographic image forming apparatus including a developing device,
An image forming apparatus comprising the toner cartridge according to claim 1 as a toner cartridge for supplying toner to the developing device.

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