HK1084736B

HK1084736B - Cartridge, image forming apparatus and toner agitation member

Info

Publication number: HK1084736B
Application number: HK06106980.3A
Authority: HK
Inventors: 石井昌宏
Original assignee: Brother Kogyo Kabushiki Kaisha
Priority date: 2004-08-11
Filing date: 2006-06-19
Publication date: 2009-08-14

Description

Cartridge, image forming apparatus, and toner agitating member

Technical Field

The invention relates to a cartridge, an image forming apparatus, and a toner agitating member.

Background

In an image forming apparatus of an electrophotographic method such as a laser printer, thin layer toner is formed on a developing roller by bringing a layer thickness regulating blade into pressure contact with the developing roller. The electrostatic latent image on the photosensitive member is visualized as a toner image with this thin layer of toner, and then the visualized toner image is transferred onto a sheet of paper.

For example, in the image forming apparatus disclosed in JP-A-2001-100501, the toner storage chamber is disposed adjacent to the developing chamber in which the developing roller is disposed. In the toner storage chamber, an agitator (toner agitating member) for agitating the toner and supplying the toner to an opening portion communicating with the developing chamber is provided so as to be driven to rotate in the toner storage chamber. The agitator has a support member made of ABS (acrylonitrile-butadiene-styrene) resin and integrally formed around the rotation shaft. A flexible film formed of PET or the like and having a thickness of 100 μm is attached to the distal end portion of the support member. When the supporting member is driven to rotate, the film slides on the inner wall surface of the toner storage chamber and undergoes bending deformation, and when the film reaches the opening portion, the film is restored to its original shape, and toner is discharged to the developing chamber through the opening portion.

Disclosure of Invention

However, in the above structure, since the film is attached to the support member, the number of parts increases, resulting in an increase in production cost due to labor for assembly and cost of parts.

The present invention provides a toner agitating member, a cartridge, and an image forming apparatus, in which the number of parts is reduced to reduce production costs.

According to an aspect of the present invention, there is provided a toner agitating member, including: a coupling portion disposed to rotate in the toner storage chamber around the rotation shaft and extending radially outward from the rotation shaft, and an agitating plate disposed at a distal end of the coupling portion for scraping toner deposited on a bottom of the toner storage chamber and supplying it to a toner supply opening provided in the toner storage chamber when the coupling portion rotates. The connecting portion and the agitating plate are integrally formed of the same material.

According to another aspect of the present invention, there is provided a cartridge comprising: the toner stirring member described above; and a toner storage chamber provided with a toner supply opening

According to still another aspect of the present invention, there is provided an image forming apparatus including: the toner stirring member described above; a toner storage chamber provided with a toner supply opening; an image carrier on which an electrostatic latent image is formed; an exposure unit for exposing the electrostatic latent image by applying a laser beam to the charged image carrier; a developing unit that develops the electrostatic latent image formed on the image carrier into a toner image with toner supplied through the toner supply opening; and a transfer unit for transferring the toner image carried on the image carrier onto a recording medium.

Since the toner agitating member has the agitating plate for agitating and supplying the toner and the connecting portion for connecting the agitating plate and the rotary shaft, which are integrally formed in the same material, the number of parts is reduced to suppress the production cost required for assembling the parts.

Drawings

The invention may be more readily described by reference to the accompanying drawings in which:

fig. 1 is a cross-sectional side view of a laser printer as an image forming apparatus according to a first embodiment of the present invention in a state where a front cover is closed;

FIG. 2 is a cross-sectional side view of the laser printer shown in FIG. 1 with the front cover open;

fig. 3 is a cross-sectional side view of the process cartridge;

FIG. 4 is a cross-sectional side view of the agitator and containment case with the distal end of the agitator plate positioned adjacent the rear end of the arcuate wall;

FIG. 5 is a perspective view of the agitator;

FIG. 6 is a cross-sectional side view of the agitator and the housing case with the distal end of the agitating plate at the same height as the lower opening edge portion of the toner supply opening;

FIG. 7 is a cross-sectional side view of the agitator and the accommodation casing when the inner end portion of the inclined surface is located at the same height as the upper opening edge portion of the toner supply opening;

fig. 8 is a cross-sectional side view of the agitator and the accommodation casing when the lower opening edge portion of the toner supply opening is located on the extension line of the inclined surface;

FIG. 9 is a cross-sectional side view of an agitator and a containment housing according to a second embodiment; and

fig. 10 is a perspective view of the agitator.

Detailed Description

[ first embodiment ]

A first embodiment of the present invention will be described hereinafter with reference to fig. 1 to 8.

Fig. 1 and 2 are cross-sectional side views showing a laser printer as an image forming apparatus according to an embodiment of the present invention. The laser printer 1 has a main body casing 2, a feeding section 4 accommodated in the main body casing 2 for feeding a sheet 3 as a recording medium, and an image forming section 5 for forming an image on the fed sheet 3.

A cartridge access opening 6 for mounting and dismounting the process cartridge 20 is formed in one wall of the main body casing 2, and a front cover 7 for opening or closing the opening 6 is provided. The front cover 7 is rotatably supported around a cover shaft (not shown) inserted through a lower end portion of the front cover 7. Thus, when the front cover 7 is closed around the cover axis, the cartridge access opening 6 is closed by the front cover 7, as shown in fig. 1. When the front cover 7 is opened (tilted) about the cover axis as a fulcrum, the cartridge access opening 6 is opened as shown in fig. 2, whereby the process cartridge 20 can be mounted on the main body casing 2 or dismounted from the main body casing 2 through the cartridge access opening 6. For convenience, the side on which the front cover 7 is provided (the right side in fig. 1) is referred to as "front side", and the opposite side (the left side in fig. 1) is referred to as "rear side".

The feeding portion 4 has a sheet feeding tray 9 movably attached on the bottom of the main body casing 2, a sheet feeding roller 10 and a separation pad 11 disposed above a front end portion of the sheet feeding tray 9, a pickup roller 12 disposed behind the sheet feeding roller 10, a nip roller 13 disposed relatively downward in front of the sheet feeding roller 10, a paper dust removing roller 8 disposed relatively upward in front of the sheet feeding roller 10, and a registration roller 14 disposed upward behind the sheet feeding roller 10.

A paper pressing plate 15 on which the paper 3 is stacked is provided inside the paper feeding tray 9. The paper pressing plate 15 is swingably supported at the rear end portion, and can swing between a lying position of the bottom plate 16 of the paper feeding tray 9 placed downward along the front end portion and an inclined conveying position where the front end portion is placed upward.

A lever 17 for lifting the front end portion of the paper pressing plate 15 is provided at the front end portion of the paper feeding tray 9. The lever 17 is formed to have a cross section of letter L shape and is inserted from the front side of the paper pressing plate 15 to the lower side of the paper pressing plate 15 with its upper end portion connected to a lever shaft 18 provided in the front end portion of the paper feeding tray 9 and its rear end portion in contact with the front end portion of the lower surface of the paper pressing plate 15. Therefore, when a rotational driving force in the clockwise direction in the drawing is input to the lever shaft 18, the lever 17 rotates about the fulcrum of the lever shaft 18, causing the rear end portion of the lever 17 to lift the front end portion of the paper pressing plate 15 to position the paper pressing plate 15 at the conveying position.

When the paper pressing plate 15 is positioned at the feeding position, the paper 3 on the paper pressing plate 15 is pressed against the pickup roller 12, and is fed between the paper feeding roller 10 and the separation pad 11 with the rotation of the pickup roller 12.

On the other hand, when the paper feeding tray 9 is separated from the main body casing 2, the front end portion of the paper pressing plate 15 moves downward due to its own weight, so that the paper pressing plate 15 is located in the lying position. When the platen 15 is in the lying position, the sheet 3 can be stacked on the platen 15.

When placed between the paper feed roller 10 and the separation pad 11 and fed by the rotation of the paper feed roller 10, the sheets 3 fed between the paper feed roller 10 and the separation pad 11 by the pickup roller 12 are reliably processed one by one. The fed sheet 3 passes between the sheet feeding roller 10 and the pinch roller 13, and is then conveyed to the registration roller 14 after paper dust is removed by the paper dust removing roller 8.

The registration roller 14 is composed of a pair of rollers, which register the sheet 3 and then convey the sheet to a transfer position between the photosensitive drum 29 and the transfer roller 32, where the toner image on the photosensitive drum 29 is transferred onto the sheet 3.

The image forming portion 5 has a scanning portion 19 as an exposure unit, a process cartridge 20, and a fixing portion 21.

The scanning section 19 is provided in an upper portion in the main body casing 2, and has a laser light source, not shown, a polygon mirror 22, an f θ lens 23, a mirror 24, a lens 25, and a mirror 26 that are driven to rotate. The laser beam emitted from the laser light source based on image data is deflected by the polygon mirror 22 across the f θ lens 23, turned backward in the optical path by the mirror 24 to pass through the lens 25, turned downward in the optical path by the mirror 26, and applied on the surface of the photosensitive drum 29 of the process cartridge 20 as indicated by a dotted line.

Fig. 3 is a cross-sectional side view of the process cartridge 20. The process cartridge 20 is detachably attached to the main body casing 2 below the scanning section 19. As one frame, the process cartridge has an upper frame 27 as a first frame and a lower frame 28 as a second frame, and the lower frame 28 and the upper frame 27 are formed separately but may be combined with the upper frame 27 as shown in fig. 3. Also, the process cartridge 20 has, in the chassis, a photosensitive drum 29 as an image carrier, a scorotron type charger 30 as a charging unit, a developing cartridge 31, a transfer roller 32 as a transfer unit, and a cleaning brush 33.

The photosensitive drum 29 is formed like a cylinder, and has a drum main body 34 whose top surface layer is formed of a positively charged photosensitive layer made of polycarbonate, and a metal drum shaft 35 as a shaft extending in the longitudinal direction of the drum main body 34 on the shaft center of the drum main body 34. A drum shaft 35 is supported on the upper frame 27, and a drum main body 34 is rotatably supported around the drum shaft 35, whereby the photosensitive drum 29 is rotatably provided in the upper frame 27 around the drum shaft 35.

The scorotron type charger 30 is supported on the upper frame 27, and is disposed obliquely upward behind the photosensitive drum 29 and opposite to the photosensitive drum 29 with a predetermined interval from the photosensitive drum 29 so as not to contact. The scorotron type charger 30 has a discharge line 37 disposed at a predetermined interval with respect to the photosensitive drum 29, and a grid 38 disposed between the discharge line 37 and the photosensitive drum 29 for controlling the amount of discharge from the discharge line 37 to the photosensitive drum 29. The scorotron charger 30 performs corona discharge on the discharge wire 37 by applying a bias to the grid electrode 38 and applying a high voltage to the discharge wire 37, and thus uniformly charges the surface of the photosensitive drum 29 with positive polarity.

The scorotron type charger 30 is provided with a cleaning member 36 for cleaning the discharging wire 37 held in the middle thereof.

The developing cartridge 31 is detachably attached to the lower frame 28. The developing cartridge 31 has a housing case 60 opened at the rear side like a cartridge, and has a toner storage chamber 61 formed at the front side inside and a developing chamber 62 formed at the rear side. The two chambers communicate through the toner supply opening 63.

The toner storage chamber 61 is filled with positively charged toner including a nonmagnetic component as a developer. The toner used may be a polymerized toner produced by copolymerizing a polymerized monomer, such as a styrene-based monomer, e.g., styrene, or an acrylic-based monomer, e.g., acrylic acid, alkyl (C1 to C4) acrylate or alkyl (C1 to C4) methacrylate, by suspension polymerization. This polymer toner is almost spherical, has excellent fluidity, and can perform image formation of high image quality.

Such a toner is mixed with a toner such as carbon black or paraffin, and an additive such as silica is added to improve fluidity. The average particle size of the toner is approximately between 6 and 10 μm.

Also, an agitator 64 is provided as a toner agitating member in the toner storage chamber 61. The agitator 64 is driven to rotate by inputting an urging force from a motor, not shown, agitates the toner in the toner storage chamber 61 by the rotation, and discharges the toner to the developing chamber 62 through the toner supply opening 63. The toner storage chamber 61 and the toner supply opening 63 of the housing case 60 and the agitator 64 constitute a toner agitating device 65. The structure of the toner stirring device 65 will be described later in detail.

In the developing chamber 62, a supply roller 40, a developing roller 41 as a developing unit, and a layer thickness regulating blade 42 are provided.

The supply roller 40 is disposed at a lower portion behind the toner supply opening 63 and is rotatably supported in the accommodating case 60 of the developing cartridge 31. The supply roller 40 is constructed by covering a metal roller shaft with a roller body made of a conductive foam material. The supply roller 40 is driven to rotate by inputting an urging force from a motor, not shown.

The developing roller 41 is rotatably supported in the accommodating case 60 of the developing cartridge 31 with it being in contact with the supply roller 40 so as to be compressed against each other behind the supply roller 40. Also, the developing rollers 41 are in contact with the photosensitive drum 29 facing each other with the developing cartridge 31 mounted to the lower frame 28. The developing roller 41 is configured by covering the metal roller shaft 44 with a roller body made of a conductive rubber material. The roller body of the developing roller 41 is covered with a coating layer of fluorine-containing urethane rubber or silicone rubber on the surface of the roller body made of conductive urethane rubber or silicone rubber containing carbon particles. A developing bias is applied to the developing roller 41 at the time of development. Also, the developing roller 41 is driven to rotate in the same direction as the supplying roller 40 by inputting an urging force from a motor, not shown.

The layer thickness regulating blade 42 has a pressing portion 47 made of insulating silicone rubber with a semicircular cross section at the distal end portion of a blade main body 46 made of a metal spring piece. The layer thickness regulating blade 42 is supported above the developing roller 41 in the accommodating case 60 of the developing cartridge 31, and the pressing portion 47 is pressed against the developing roller 41 due to the elastic force of the blade main body 46.

The toner discharged into the developing chamber 62 through the toner supply opening 63 is supplied to the developing roller 41 by the rotation of the supply roller 40, and then positively charged due to the friction between the supply roller 40 and the developing roller 41. The toner supplied on the developing roller 41 enters between the pressing portion 47 of the layer thickness regulating blade 2 and the developing roller 41 with the rotation of the developing roller 41 and is carried on the developing roller 41 as a thin layer having a predetermined thickness.

The transfer roller 32 is rotatably supported on the lower frame 28, and is disposed to form a nip portion with the photosensitive drum 29 by being brought into contact with the photosensitive drum 29 so as to face vertically with the upper frame 27 and the lower frame 28 being joined. The transfer roller 32 is configured by covering the metal roller shaft 45 with a roller body made of a conductive rubber material. A transfer bias is applied to the transfer roller 32 at the time of transfer. Also, the transfer roller 32 is driven to rotate in the opposite direction to the photosensitive drum 29 by inputting an urging force from a motor, not shown.

The cleaning brush 33 is attached to the lower frame 28, and is disposed behind the photosensitive drum 29 in confronting contact with the photosensitive drum 29 with the upper frame 27 and the lower frame 28 joined.

With the rotation of the photosensitive drum 29, the surface of the photosensitive drum 29 is first uniformly positively charged by the scorotron-type charger 30, and then exposed by rapid scanning of the laser beam from the scanning section 19 to form an electrostatic latent image corresponding to an image to be formed on the sheet 3.

Subsequently, when the positively charged toner carried on the developing roller 41 comes into face-to-face contact with the photosensitive drum 29 with the rotation of the developing roller 41, the toner is supplied to an electrostatic latent image formed on the surface of the photosensitive drum 29, or an exposed portion exposed by a laser beam and having a low potential on the uniformly positively charged surface of the photosensitive drum 29. Thus, the electrostatic latent image of the photosensitive drum 29 is visualized, and the toner image is carried on the surface of the photosensitive drum 29 by reversal development.

Thereafter, when the sheet 3 conveyed by the registration roller 14 passes through the transfer position between the photosensitive drum 29 and the transfer roller 32 as shown in fig. 1, the toner image carried on the surface of the photosensitive drum 29 is transferred onto the sheet 3 by the transfer bias applied to the transfer roller 32. The sheet 3 on which the toner image is transferred is conveyed to the fixing section 21.

The transfer residual toner remaining on the photosensitive drum 29 after the transfer is collected by the developing roller 41. Also, paper dust from the paper 3 stuck on the photosensitive drum 29 after transfer is collected by the cleaning brush 33.

The fixing portion 21 is disposed behind the process cartridge 20, and has a fixing frame 48, and a heating roller 49 and a pressure roller 50 in the fixing frame 48.

The heating roller 49 has a metal tube whose surface is coated with a fluorine resin, and a tungsten halogen lamp for heating in the metal tube, and is driven to rotate by inputting an urging force from a not-shown motor.

The pressure roller 50 is disposed to face under the heat roller 49 to pressurize the heat roller 49. The pressure roller 50 is constituted by covering a metal roller shaft with a roller body made of a rubber material, and is driven by rotating and driving the heat roller 49.

In the fixing section 21, the toner transferred on the sheet 3 in the transfer position is thermally fixed while the sheet 3 passes between the heating roller 49 and the pressure roller 50. The sheet 3 with the fixed toner is conveyed on a sheet discharge path 51 extending vertically toward the upper surface of the main body casing 2. The sheet 3 conveyed on the sheet discharge path 51 is discharged onto the sheet discharge tray 63 by the sheet discharge roller 52 provided on the upper side of the sheet discharge tray 53 formed on the upper surface of the main body casing 2.

The structure of the toner agitating device 65 will be described in detail below. Fig. 4 and 6 to 8 are cross-sectional side views of the housing case 60 and the agitator 64 constituting the toner agitating device 65, and fig. 5 is a perspective view of the agitator 64.

The accommodation case 60 is formed like a laterally extending long box and made of a synthetic resin material such as ABS resin, and has a case main body portion 66 of which the rear surface and the upper surface are partially opened and a cover portion 67 combined to cover the upper surface opening of the case main body portion 66, as shown in fig. 4. The housing body portion 66 has a bottom wall 68 that covers the lower surface of the interior space that houses the housing 60. In the toner storage chamber 61 formed in front in the internal space of the housing case 60, the shaft portion 74 of the agitator 64 is supported in the lateral direction. On the bottom wall 68 of the side surface of the toner storage chamber 61, an arc-shaped wall 68A, which has a cross section like a circular arc centered on the shaft portion 74, is formed in a range from the front of the shaft portion 74 to the diagonally lower rear side of the shaft portion 74. The toner storage chamber 61 takes the form of a cylindrical space of a radius from the shaft portion 74 to the length of the arc-shaped wall 68A centered on the shaft portion 74, as a whole, being slightly enlarged to extend to the rear and obliquely upward and forward. An upwardly projecting lower partition wall 69 whose cross section is like a peak is continuously formed behind the curved wall 68A, whereby the upper surface in the region from the highest portion of the lower partition wall 69 (the lower opening edge portion 69A of the toner supply opening 63) to the rear end of the curved wall 68A becomes a flat feeding plane 69B which is inclined in the tangential direction of the circumference of the shaft portion 74 with respect to the center of the circle.

Above the lower partition wall 69, a flat plate-like upper partition wall 70 extends downward from the lower surface of the cover portion 67, whereby the toner storage chamber 61 and the developing chamber 62 are longitudinally partitioned by the upper partition wall 70 and the lower partition wall 69. The toner supply opening 63 is formed between a lower opening edge portion 69A of the upper end of the lower partition wall 69 and an upper opening edge portion 70A of the lower end of the upper partition wall 70, whereby the toner storage chamber 61 and the developing chamber 62 communicate via the toner supply opening 63. The toner supply opening 63 is provided at a rear position of the shaft portion 74, and downstream of the agitator 64 in the rotational direction (clockwise direction in fig. 4) with respect to the arc-shaped wall 68A covering the bottom surface of the toner storage chamber 61. Also, the lower opening edge portion 69A of the toner supply opening 63 is disposed at a position lower than the shaft portion 74, and the upper opening edge portion 70A is disposed at a position higher than the shaft portion 74. The inner width dimensions of the toner storage chamber 61, the developing chamber 62, and the toner supply opening 63 are almost the same in the lateral direction.

On the left and right side walls of the casing main body portion 66, window holes 71 (see fig. 6) for detecting the remaining amount of toner are provided in the toner storage chamber 61 at positions diagonally downward in front of the lower partition wall 69 and behind the shaft portion 74. Each window hole 71 is covered and closed with a transparent window member 72. The main body casing 2 is provided with a light emitting element (not shown) outside one of the window holes 71, and a light receiving element (not shown) outside the other window hole 71. The detection light emitted from the light-emitting element and transmitted through the housing case 60 is detected by the light-receiving element to determine the presence or absence of toner depending on the output value of the light.

The agitator 64 is integrally formed of a synthetic resin material such as ABS resin, and as a whole, has a certain rigidity so as not to be deformed by pressure from the toner when driven to rotate. The agitator 64 has a shaft portion 74 like a round bar as a rotation shaft. When both end portions of the shaft portion 74 are fitted into bearing holes (not shown) provided on both left and right side walls of the toner storage chamber 61, the agitator 64 is supported to freely rotate in a horizontal state in the lateral direction around the shaft portion 74, as shown in fig. 4 and 5. A gear mechanism (not shown) is provided on the left outer side surface of the housing case 60, and transmits the urging force from a not-shown motor to the shaft portion 74, so that the agitator 64 is driven to rotate in the clockwise direction in fig. 4.

On the outer circumferential surfaces of the shaft portions 74 near the two left and right end portions, plate-like wiper mounting portions 75 are disposed radially outward and extend in the same direction. Each wiper mounting portion 75 has a mounting pin 75A protruding from the downstream face in the rotation direction. A wiper 76 made of urethane rubber like a rectangle is attached to each mounting pin 75A, one end of which protrudes in the direction of the shaft portion 74. Each wiper 76 slides on the surface of the window member 72 to wipe toner adhering to the surface as the shaft portion 74 rotates.

On the outer circumferential surface of the shaft portion 74, connection portions 77 are provided on opposite sides of the wiper mounting portion 75 and extend radially outward. The coupling portion 77 has a plurality of plates 78 perpendicular to the shaft portion 74, which are arranged at almost regular intervals over substantially the entire width of the toner storage chamber 61 in the direction of the shaft portion 74, each plate supporting an agitating plate 80 at its distal end. Also, rectangular through holes 79 penetrating in a tangential direction of rotation are formed between the adjacent slabs 78. These through holes 79 are almost uniformly arranged in parallel in the direction of the shaft portion 74.

The agitating plate 80 is like a rectangular flat plate having a width dimension of substantially the entire width of the toner storage chamber 61 and extending outward in the radial direction of the shaft portion 74 from the distal end of the connecting portion 77. In this agitating plate 80, the surface on the downstream side in the rotational direction is an outwardly inclined surface 80A which gradually inclines toward the upstream side in the rotational direction as it extends to its distal end. An angle α (see fig. 4) between the inclined surface 80A and the extending direction of the connecting portion 77 is 130.5 °. The angle alpha may be set in the range of 90 deg. < alpha < 180 deg.. Also, a length L1 (see fig. 8) from an outer end portion (opposite end portion of the shaft portion 74) to an inner end portion (end portion of the shaft portion 74) of the inclined surface 80A is 11.5mm, and a length L2 from an inner end portion of the inclined surface 80A to the shaft portion 74 is 10.5mm, so that the length L1 is set to be greater than the length L2.

Further, the length L3 from the center of the shaft portion 74 to the distal end of the agitating plate 80 is 19.0mm, and the length L4 from the center of the shaft portion 74 to the inner surface of the arc-shaped wall 68A is 20.0mm, so that the length L3 is set slightly smaller than the length L4, as shown in fig. 4. Therefore, the agitator 64 is always driven to rotate without coming into contact with the inner wall surface of the toner storage chamber 61, and thus the top of the agitating plate 80 passes extremely close to the arc-shaped wall 68A.

Also, when the distal end of the agitating plate 80 reaches the position at the same height as the lower opening edge portion 69A of the toner supply opening 63, the inclination angle β of the inclined surface 80A to the horizontal line is 55.7 °, as shown in fig. 6. The angle β may be set in the range of 20 ° to 80 °.

Further, the height L5 of the toner supply opening 63 is 11.8mm, and when the inner end portion of the inclined surface 80A is at the same height position as the upper opening edge portion 70A of the toner supply opening 63, the height L6 of the inclined surface 80A is 8.7mm, as shown in fig. 7. In other words, when the inner end portion of the inclined surface 80A is at the same height position as the upper opening edge portion 70A of the toner supply opening 63, the outer end portion of the inclined surface 80A is disposed at a higher position than the lower opening edge portion 69A of the toner supply opening 63.

Also, when the lower opening edge portion 69A of the toner supply opening 63 reaches the extension line of the inclined surface 80A, the inclination angle γ of the inclined surface 80A to the horizontal line is 44.0 °, as shown in fig. 8. The angle γ may be set in the range of 20 ° to 80 °.

The operation of stirring and supplying the toner by the toner stirring device 65 will be described below.

The agitator 64 is driven to rotate at a speed of one revolution per second, for example, by an urging force from a motor, not shown. When the distal end of the agitating plate 80 moves from the front end position to the rear end of the arc-shaped wall 68A, the toner deposited on the bottom of the toner storage chamber 61 is accordingly pressed by the inclined surface 80A toward the downstream in the rotational direction and scraped off from the feeding plane 69B to the toner supply opening 63, as indicated by the arrow in fig. 4. With the rotation of the agitator 64, most of the toner near the shaft portion 74 passes through the through-hole 79 provided in the connecting portion 77 from the downstream side to the upstream side in the rotation direction.

When the agitator 64 is further rotated from the state of fig. 4 and the distal end of the agitating plate 80 reaches the vicinity of the toner supply opening 63, more specifically, when the distal end of the agitating plate 80 reaches the position at the same height as the lower opening edge portion 69A of the toner supply opening 63 (see fig. 6), or when the lower opening edge portion 69A reaches the extension line of the inclined surface 80A (see fig. 8), the toner scraped by the inclined surface 80A is conveyed to the side of the toner supply opening 63 to slide downward along the inclined surface 80A (see the arrow in fig. 6 or 8) because the inclined surface 80A is inclined downward to the side of the toner supply opening 63. When the agitating plate 80 passes near the toner supply opening 63, the toner conveyed by the inclined surface 80A smoothly flows into the toner supply opening because the height dimension of the toner supply opening 63 is larger than the height dimension of the inclined surface 80A (see fig. 7).

When some remaining toner does not fall from the inclined surface 80A into the toner supply opening when the agitating plate 80 passes in the vicinity of the toner supply opening 63, the toner is also lifted when the agitating plate 80 is lifted, and then falls from the inclined surface 80A to be mixed with the toner deposited at the bottom.

According to the above-described embodiment, since the agitator 64 includes the agitating plate 80 for agitating and supplying the toner, and the connecting portion 77 for connecting the agitating plate 80 and the shaft portion 74 together, which are integrally formed of the same material, the number of parts is reduced and the manufacturing cost required for assembling the parts is suppressed.

Also, since the downstream face of the agitating plate 80 in the rotational direction is an inclined surface 80A which is gradually inclined toward the upstream side in the rotational direction as it extends to its distal end, the toner is guided radially outward by the inclined surface 80A when the agitator 64 is driven to rotate. Therefore, the toner in the toner storage chamber 61 is efficiently conveyed into the toner supply opening 63.

Also, since the inclined surface 80A is inclined to gradually descend near the distal end when the distal end of the agitating plate 80 reaches the same height position as the lower opening edge portion 69A of the toner supply opening 63 (see fig. 6), the toner scraped by the inclined surface 80A is conveyed to the side of the toner supply opening 63 to slide downward along the inclined surface 80A even in the case where the remaining amount of toner is small.

Also, when the distal end of the agitating plate 80 reaches the same height position as the lower opening edge portion 69A of the toner supply opening 63 (see fig. 6), the inclination angle of the inclined surface 80A to the horizontal line is set from 20 ° to 80 °. Here, when the inclination angle of the inclined surface 80A is sharp, the force for conveying the toner to the side of the toner supply opening 63 is large, but the amount of the toner conveyed is small. Also, when the inclination angle of the inclined surface 80A is relatively large, the opposite result is obtained. Therefore, when the inclination angle of the inclined surface 80A is between 20 ° and 80 ° as in the present embodiment, the toner can be most efficiently conveyed into the toner supply opening 63.

Also, since the inclined surface 80A gradually descends near the distal end due to the inclination when the lower opening edge portion 69A of the toner supply opening 63 reaches the extension line of the inclined surface 80A (see fig. 8), the toner scraped by the inclined surface 80A is conveyed to the side of the toner supply opening 63 to slide downward along the inclined surface 80A even in the case where the remaining amount of the toner is small.

Also, when the lower opening edge portion 69A of the toner supply opening 63 reaches the extension line of the inclined surface 80A, the inclination angle of the inclined surface 80A to the horizontal line is set to be between 20 ° and 80 °. Here, when the inclination angle of the inclined surface 80A is sharp, the force for conveying the toner to the side of the toner supply opening 63 is large, but the amount of the toner conveyed is small. Also, when the inclination angle of the inclined surface 80A is relatively large, the opposite result is obtained. Therefore, when the inclination angle of the inclined surface 80A is between 20 ° and 80 ° as in the present embodiment, the toner can be most efficiently conveyed into the toner supply opening 63.

Also, when the inner end portion of the inclined surface 80A is at the same height position as the upper opening edge portion 70A of the toner supply opening 63, the outer end portion of the inclined surface 80A is disposed at a higher position than the lower opening edge portion 69A of the toner supply opening 63. That is, since the height dimension of the toner supply opening 63 is set larger than the height dimension of the inclined surface 80A, the toner conveyed by the inclined surface 80A smoothly flows into the toner supply opening 63.

Also, since the length L1 from the outer end portion to the inner end portion of the inclined surface 80A is set to be larger than the length from the inner end portion to the shaft portion 74 of the inclined surface 80A, the length (area) of the inclined surface 80A is maintained so that toner can be efficiently stirred and supplied.

Also, since the connecting portion 77 is provided with the through hole 79 penetrating in the tangential direction of rotation, the pressure applied from the toner at the time of driving rotation is reduced, and the load on the driving unit of the agitator 64 is reduced.

Also, since a plurality of through holes 79 are axially arranged in parallel in the connecting portion 77, the strength is improved due to the number of regions (plates 78) connecting the distal end and the rotating shaft 45 disposed between the through holes 79, as compared with the case where only one through hole is provided so as to axially extend over a large length. In the present embodiment in particular, since the plurality of through holes 79 are almost uniformly arranged in the axial direction, the load on the agitator 64 at the time of driving rotation is prevented from being deviated in the axial direction.

Also, since the agitating plate 80 of the agitator 64 is driven to rotate without contacting the inner wall surface of the toner storage chamber 61, a load is prevented from being imposed on the driving unit due to friction of the agitating plate 80 with the inner wall surface of the toner storage chamber 61.

Also, since the agitator 64 is formed with such rigidity that it is not deformed by the pressure from the toner as a whole at least when driven to rotate, the toner can be agitated and supplied more efficiently than when an agitator of the same shape is formed using a flexible film.

Also, since the toner stored in the toner storage chamber 61 is a polymer toner containing a non-magnetic component, the very high fluidity allows the toner to be excellently agitated by the agitator 64.

[ second embodiment ]

A second embodiment of the present invention will be described below with reference to fig. 9 and 10. Fig. 9 is a cross-sectional side view of the housing case 60 and the agitator 86 constituting the toner agitating device 85 according to the present embodiment; fig. 10 is a perspective view of the agitator 86.

The agitator 86 of the present embodiment is provided with a plurality of through-holes 87 only in the connecting portion 88 at positions close to the shaft portion 74. Each through hole 87 is provided to penetrate in the tangential direction of rotation. The through holes are arranged almost uniformly in the direction of the shaft portion 74. Also, at the distal end of the connecting portion 88, a stirring surface 89 perpendicular to the tangential direction of rotation is formed continuously with the inner tip portion of the inclined surface 80A. Other structures are the same as those in the first embodiment, and thus the same or similar parts are designated by the same numerals as those in the first embodiment, and the description of the same parts is omitted.

When the agitator 86 is driven to rotate, the toner near the shaft portion 74 passes through each through-hole 87 of the connecting portion 88 from the downstream side in the rotational direction to the upstream side. Also, the toner deposited on the bottom of the toner storage chamber 61 is pressed toward the downstream side in the rotational direction by the stirring surface 89 of the connecting portion 88, and a part of the toner is raised by being on the stirring surface 89 and then falls from the stirring surface 89 to be mixed with the toner deposited on the bottom.

As described above, with the present embodiment, since the plurality of through-holes 87 are provided only at the positions in the connecting portion near the shaft portion 74, toner is efficiently agitated even at the distal end of the connecting portion 88 while suppressing the load on the drive unit of the agitator 86. If the through-hole is provided only at a position near the distal end, toner is agitated only in a region near the shaft portion 74, although the effect of reducing the load of the drive unit is expected. Therefore, particularly when the remaining amount of toner is small, the toner is less likely to be placed in an area near the shaft portion 74, and thus it is not expected that the toner is efficiently stirred. On the other hand, according to the present embodiment, both results can be expected.

Although the present invention has been described above based on the embodiments, the present invention is not limited thereto. The present invention may be modified or variously modified without departing from the spirit of the present invention. For example, although the agitator is made of synthetic resin in the above-described embodiment, the agitator may be made of a metal material.

Claims

1. A cartridge, comprising:

a toner storage chamber provided with a toner supply opening; and

a toner agitating member, the toner agitating member including: a coupling portion provided to rotate in the toner storage chamber around the rotation shaft and extending radially outward from the rotation shaft; and an agitating plate provided at a distal end of the coupling portion for scraping the toner deposited on the bottom of the toner storage chamber and supplying it to the toner supply opening when the coupling portion is rotated, the coupling portion and the agitating plate being formed integrally of the same material;

wherein a lower edge portion of the toner supply opening is disposed at a position lower than the rotation shaft when the cartridge is mounted in the image forming apparatus;

wherein a surface of the agitating plate on the downstream side in the rotational direction is an inclined surface inclined toward the upstream side in the rotational direction as it extends from the connecting portion toward the distal end thereof;

wherein the inclined surface is gradually inclined downward toward the distal end thereof when the distal end of the agitating plate reaches a position at the same height as the lower opening edge portion of the toner supply opening;

wherein when the distal end of the agitating plate reaches a position at the same height as the lower opening edge portion of the toner supply opening, the inclination angle of the inclined surface to the horizontal line is between 20 ° and 80 °;

wherein the agitating plate rotates without contacting an inner wall surface of the toner storage chamber.

2. The cartridge according to claim 1, further comprising a developing unit that develops the electrostatic latent image formed on the image carrier with toner supplied through the toner supply opening.

3. The cartridge according to claim 2, wherein the toner stored in the toner storage chamber is a polymer toner containing a non-magnetic component polymer toner.

4. The cartridge of claim 1, further comprising:

an image carrier on which an electrostatic latent image is formed; and

and a developing unit that develops the electrostatic latent image formed on the image carrier with toner supplied through the toner supply opening.

5. The cartridge according to claim 1, wherein the inclined surface is gradually inclined downward toward a distal end thereof when a lower opening edge portion of the toner supply opening reaches an extension line of the inclined surface.

6. The cartridge according to claim 5, wherein when the lower opening edge portion of the toner supply opening reaches an extension line of the inclined surface, an inclination angle of the inclined surface to a horizontal line is between 20 ° and 80 °.

7. The cartridge according to claim 1, wherein when a base end of the inclined surface opposite to the distal end is at a position having the same height as an upper opening edge portion of the toner supply opening, the distal end of the inclined surface is disposed at a position higher than the lower opening edge portion of the toner supply opening.

8. The cartridge according to claim 1, wherein a length dimension from a distal end of the inclined surface to a base end opposite to the distal end is set to be larger than a length dimension from a base end of the inclined surface to the rotation axis.

9. The cartridge according to claim 1, wherein the connection portion is formed with a through hole penetrating the connection portion in a tangential direction of rotation.

10. The cartridge according to claim 9, wherein the through-hole comprises a plurality of through-holes arranged in a direction parallel to the rotation axis.

11. The cartridge according to claim 10, wherein the plurality of through holes are provided only at positions adjacent to the rotational axis of the connection portion.

12. The cartridge according to claim 1, wherein the pink agitating member is formed to have such rigidity that it is not substantially entirely deformed by a pressure applied by the toner at least during rotation.

13. An image forming apparatus, characterized by comprising:

a toner storage chamber provided with a toner supply opening;

an image carrier on which an electrostatic latent image is formed;

an exposure unit for exposing the electrostatic latent image by applying a laser beam to the charged image carrier;

a developing unit that develops the electrostatic latent image formed on the image carrier into a toner image with toner supplied through the toner supply opening; and

a transfer unit for transferring the toner image carried on the image carrier onto a recording medium;

wherein a lower edge portion of the toner supply opening is disposed at a position lower than the rotation shaft when a cartridge containing the toner storage chamber and the toner agitating member is mounted in the image forming apparatus;

14. A toner agitating member, comprising:

a coupling portion provided to rotate in the toner storage chamber around the rotation shaft and extending radially outward from the rotation shaft; and

an agitating plate, provided at a distal end of the joint portion, for scraping toner deposited on a bottom of the toner storage chamber and supplying the toner to a toner supply opening provided in the toner storage chamber when the joint portion rotates;

wherein, the connecting part and the stirring plate are integrally formed by the same material;