JP5723252B2 - Image forming unit and image forming apparatus - Google Patents

Description

  The present invention relates to an image forming unit and an image forming apparatus.

  Conventionally, an image forming apparatus such as a printer, a copier, a facsimile machine, a multifunction machine, for example, a printer includes an image forming unit, an LED head, a transfer roller, a fixing device, etc., and the image forming unit includes a main body of the image forming unit, That is, the image forming unit main body and a toner cartridge that is detachably attached to the image forming unit main body, and the image forming unit main body includes a photosensitive drum, a charging roller, and a developer carrier. A developing roller, a developing blade, a toner supply roller, a cleaning blade, and the like are arranged. A developing device is configured by the developing roller, the developing blade, the toner supply roller, the toner cartridge, and the like.

  In the printer, the surface of the photosensitive drum uniformly charged by the charging roller is exposed by the LED head to form an electrostatic latent image. On the other hand, the toner as the developer supplied from the toner cartridge into the image forming unit main body is supplied to the developing roller by the toner supply roller, and a thin layer of toner is formed on the developing roller by the developing blade. Then, the toner on the developing roller is attached to the electrostatic latent image on the photosensitive drum, and the electrostatic latent image is developed to form a toner image on the photosensitive drum. Subsequently, the toner image is transferred onto a sheet by a transfer roller, and is fixed on the sheet by a fixing device to form an image.

  By the way, there is provided a printer in which a brush roller is used as the toner supply roller and toner is supplied from the brush roller to the developing roller (see, for example, Patent Document 1).

JP 2000-258987 A

  However, in the conventional printer, if the brush roller is buried in the toner in the image forming unit main body, the toner enters the gap between the brushes of the brush roller and becomes clogged.

  Therefore, when the printer is used for a long period of time, the elasticity of the brush becomes low, and the toner cannot be stably supplied to the developing roller. As a result, the image quality is degraded.

  The present invention solves the problems of the conventional printer, can stably supply the developer to the developer carrying member, and can prevent the image quality from deteriorating and the image forming unit. An object is to provide a forming apparatus.

  For this purpose, in the image forming unit of the present invention, a developer carrying member carrying a developer and a developer carrying member that is rotatably disposed facing the developer carrying member are supplied to the developer carrying member. A first supply member, a second supply member that is rotatably disposed in contact with the first supply member, and supplies developer to the first supply member; the developer carrier; 1. A housing that houses a second supply member and forms a developer holding space for holding the developer, and a door that is openably and closably disposed, and the developer in the developer containing chamber is placed in the developer holding space. An opening / closing member for supplying, developer level determination processing means for determining the level of the upper surface of the developer in the developer holding space, and the opening / closing member according to the level of the upper surface of the developer in the developer holding space. Developer supply processing means for opening and closing.

  Further, the level of the upper surface of the developer held in the developer holding space is set lower than the contact facing portion of the first and second supply members.

  According to the present invention, in the image forming unit, the developer carrying member carrying the developer and the developer carrying member are rotatably disposed opposite to the developer carrying member, and the developer is supplied to the developer carrying member. A first supply member, a second supply member that is rotatably disposed in contact with the first supply member, and supplies developer to the first supply member; the developer carrier; 1. A housing that houses a second supply member and forms a developer holding space for holding the developer, and a door that is openably and closably disposed, and the developer in the developer containing chamber is placed in the developer holding space. An opening / closing member for supplying, developer level determination processing means for determining the level of the upper surface of the developer in the developer holding space, and the opening / closing member according to the level of the upper surface of the developer in the developer holding space. Developer supply processing means for opening and closing.

  Further, the level of the upper surface of the developer held in the developer holding space is set lower than the contact facing portion of the first and second supply members.

  In this case, the level of the upper surface of the developer held in the developer holding space is set lower than the contact facing portion of the first and second supply members, so that the first supply member can be floated from the developer. .

  Therefore, the first supply member is not buried in the developer, and the developer can be stably supplied to the developer carrying member, so that it is possible to prevent the image quality from deteriorating.

1 is a schematic diagram of an image forming unit according to a first embodiment of the present invention. 1 is a conceptual diagram of a printer according to a first embodiment of the present invention. FIG. 3 is an enlarged view showing a main part of the image forming unit in the first embodiment of the present invention. It is sectional drawing of the developing roller in the 1st Embodiment of this invention. FIG. 2 is a first conceptual diagram illustrating a measuring device for measuring a resistance value of a developing roller according to the first embodiment of the present invention. It is a 2nd conceptual diagram which shows the measuring apparatus of the resistance value of the developing roller in the 1st Embodiment of this invention. It is a conceptual diagram of the level signal generator in the 1st Embodiment of this invention. It is a perspective view which shows the principal part of the level signal generator in the 1st Embodiment of this invention. It is a figure for demonstrating the detection state of the reflecting plate by the photon detection part in the 1st Embodiment of this invention. It is a 1st figure which shows operation | movement of the level signal generator in the 1st Embodiment of this invention. It is a 2nd figure which shows operation | movement of the level signal generator in the 1st Embodiment of this invention. FIG. 4 is a relationship diagram between a toner level and a light receiving time in the first embodiment of the present invention. FIG. 3 is a control block diagram of the printer in the first embodiment of the present invention. 3 is a flowchart illustrating an operation of a print control unit according to the first embodiment of the present invention. 2 is a schematic diagram of an image forming unit of Comparative Example 1. FIG. 10 is a schematic diagram of an image forming unit of Comparative Example 2. FIG. It is a figure which shows the toner level after the continuous printing test by the image forming unit of the comparative example 1 in the 1st Embodiment of this invention. It is a figure which shows the toner level after the continuous printing test by the image forming unit of the comparative example 2 in the 1st Embodiment of this invention. It is the schematic of the image forming unit in the 2nd Embodiment of this invention. FIG. 5 is a diagram for explaining a mechanism in which white spots occur in the image forming unit according to the first exemplary embodiment in a high temperature and high humidity environment. It is the schematic of the image forming unit in the 3rd Embodiment of this invention. It is a conceptual diagram of the printer in the 4th Embodiment of this invention. It is the schematic of the image forming unit in the 4th Embodiment of this invention. It is a 1st enlarged view which shows the principal part of the image forming unit in the 4th Embodiment of this invention. It is a 2nd enlarged view which shows the principal part of the image forming unit in the 4th Embodiment of this invention. It is a control block diagram of the printer in the 4th Embodiment of this invention. It is a figure which shows the principal part of the image forming unit of the comparative example 3 in the 4th Embodiment of this invention. It is a conceptual diagram of the printer in the 5th Embodiment of this invention. It is the schematic of the image forming unit in the 5th Embodiment of this invention. FIG. 10 is a control block diagram of a printer according to a fifth embodiment of the present invention. It is a flowchart which shows operation | movement of the printing control part in the 5th Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this case, a printer as an image forming apparatus will be described.

  1 is a schematic diagram of an image forming unit according to the first embodiment of the present invention, FIG. 2 is a conceptual diagram of a printer according to the first embodiment of the present invention, and FIG. 3 is a first embodiment of the present invention. FIG. 2 is an enlarged view showing a main part of the image forming unit in FIG.

  In the figure, 10 is a printer, Cs1 is a casing as a casing of the printer 10, 20 is an image forming unit (developing device), and 23 is a photoconductive drum as an image carrier disposed rotatably in the direction of arrow a. , 11 are arranged so as to face the photosensitive drum 23 and expose the surface of the photosensitive drum 23 to form an electrostatic latent image as a latent image on the surface of the photosensitive drum 23. A head 12 is arranged to face the photosensitive drum 23 so as to be rotatable in the direction of arrow b, and transfers a toner image as a developer image formed on the photosensitive drum 23 onto a sheet P as a medium. It is a transfer roller as a member.

  The image forming unit 20 includes a main body of the image forming unit 20, that is, an image forming unit main body 20a, and a toner cartridge 32 as a developer accommodating portion that is detachably attached to the image forming unit main body 20a. In the toner cartridge 32, a toner storage chamber is formed as a developer storage chamber for storing the toner 31 as the developer. A casing Cs2 as a casing of the image forming unit main body 20a includes a receiving portion Csa for receiving the toner cartridge 32.

  In order to supply the toner 31 into the image forming unit main body 20a, a toner discharge port h1 as a developer discharge port at the bottom of the toner cartridge 32 corresponds to the developer discharge port h1 in the receiving unit Csa. A toner receiving port h2 is formed as a developer receiving port, and the toner discharge port h1 is opened and closed by a shutter 32a as an opening / closing member.

  In the image forming unit main body 20a, the photosensitive drum 23 is disposed so as to be in contact with the photosensitive drum 23 so as to be rotatable in the direction of the arrow c, and to charge the surface of the photosensitive drum 23 uniformly. A charging roller 24 as an apparatus and a charging member, a developing device 90 for forming a toner image by adhering the toner 31 to the electrostatic latent image, and developing the toner image, and a tip of which is in contact with the photosensitive drum 23 A cleaning blade 29 or the like as a cleaning member that collects the toner 31 remaining on the photosensitive drum 23 after the transfer is disposed.

  The developing device 90 is disposed so as to face the photosensitive drum 23 and to be in contact with the photosensitive drum 23 so as to be rotatable in the direction of the arrow d, and as a developer carrying member for carrying the toner 31. The developing roller 21 is disposed below the developing roller 21 so as to face the developing roller 21 and to be rotatable in the direction of arrow e without contacting the developing roller 21 (without contact). A toner supply brush roller 22 as a first supply member for supplying the toner to the developing roller 21 and as a brush roller (developer supply brush roller), and in contact with the toner supply brush roller 22 above the toner supply brush roller 22 A toner supply brush flicker 27 as a developer flying member disposed in such a manner as to be disposed in contact with the developing roller 21 at the tip thereof. A developing blade 26 as a developer regulating member that forms a thin layer of toner 31 of uniform thickness on the roller 21, the developing roller 21 below the developing roller 21, facing the developing roller 21, and the developing roller 21 And a brush roller (developer recovery) that is disposed in a freely rotating manner in the direction of the arrow f in contact with the toner and collects the toner 31 remaining on the developing roller 21 without being used for development. A toner collecting brush roller 25 as a brush roller), a toner collecting brush flicker 28 as a developer flying member disposed in contact with the toner collecting brush roller 25 below the toner collecting brush roller 25, and the toner supply brush. Below the roller 22, facing the toner supply brush roller 22, and the toner supply brush roller 22 Auxiliary supply roller 30 as a second supply member for supplying toner 31 to toner supply brush roller 22 and as a developer supply member, which is arranged to be freely rotatable in the direction of arrow g. A plurality of agitating members 33a to 33d that are freely arranged and agitate and convey the toner 31 in the casing Cs2, and are rotatably arranged in the direction of the arrow k, and represent the remaining amount of the toner 31 in the casing Cs2. A detection lever 34 for detecting the level (position) of the upper surface 31a, that is, the toner level as the developer level is provided.

  The toner supply brush flicker 27 is upstream of the developing roller 21 in the rotational direction of the toner supply brush roller 22, and the toner recovery brush flicker 28 is downstream of the developing roller 21 in the rotational direction of the toner recovery brush roller 25. It is arranged.

  The casing Cs2 accommodates the developing device 90 and forms a developer holding space rm for holding the toner 31.

  The stirring members 33a to 33d and the detection lever 34 are formed of a crank-shaped metal bar and are rotated along a broken line shown in FIG. Further, the non-contact facing portion α1 is caused by the portion where the developing roller 21 and the toner supply brush roller 22 are opposed to each other without contact, and the non-contact facing portion α1 is caused by the portion where the toner supply brush roller 22 and the auxiliary supply roller 30 are opposed to each other. The contact facing part β1 is formed.

  The toner supply brush roller 22 spirally winds a brush 22b formed of a fabric woven with conductive fibers adjusted to a desired resistance value around a conductive metal core 22a. The toner recovery brush roller 25 is formed by winding a brush 25b formed of a fabric in which conductive fibers adjusted to a desired resistance value are spirally wound around a metal core bar 25a having conductivity. . The toner supply brush flicker 27 uses the elasticity of the brush 22b to cause the toner 31 held by the toner supply brush roller 22 to fly toward the developing roller 21, and the toner recovery brush flicker 28 The toner 31 held by the toner recovery brush roller 25 is caused to fly downward using the elasticity of the toner.

  The auxiliary supply roller 30 is formed by coating a metal rubber sponge layer 30b as an elastic body on a core metal 30a made of a conductive metal, in the present embodiment, made of stainless steel. The

  The toner supply brush roller 22, the agitating members 33a to 33d, and the detection lever 34 are opposite to the photosensitive drum 23, and the transfer roller 12, the charging roller 24, the developing roller 21, the auxiliary supply roller 30, and the toner recovery brush. The roller 25 is rotated in the same direction.

  As shown in FIG. 3, the developing roller 21, the toner supply brush roller 22, the toner supply brush flicker 27, the toner collection brush roller 25, the toner collection brush flicker 28, and the auxiliary supply roller 30 are separated by a gap or Arranged to form a nip.

  The gap amount d1 between the developing roller 21 and the toner supply brush roller 22, the nip amount d2 between the toner supply brush roller 22 and the toner supply brush flicker 27, and the nip amount between the development roller 21 and the toner recovery brush roller 25. d3, the nip amount d4 between the toner collection brush roller 25 and the toner collection brush flicker 28, and the nip amount d5 between the toner supply brush roller 22 and the auxiliary supply roller 30 are all set to 0.5 [mm].

  Below the image forming unit 20, in order to supply the paper P to a transfer unit formed between the photosensitive drum 23 and the transfer roller 12, a paper cassette 91 as a medium storage unit for storing the paper P, A hopping roller 15a is provided as a first conveying member for separating and conveying the paper P one by one and as a feeding roller.

  A registration roller 15b as a second conveyance member is disposed downstream of the hopping roller 15a in the medium conveyance path for conveying the paper P. Further, on the downstream side of the transfer section in the medium conveyance path, a fixing device 13 as a fixing device and a sheet P that has passed through the fixing device 13 are discharged to the main body of the printer 10, that is, to the outside of the apparatus main body. 3 is a discharge roller 15c as a conveying member.

  The fixing device 13 includes a heating roller R1 as a first roller and a pressure roller R2 as a second roller, and a heater (not shown) as a heating body is disposed in the heating roller R1. Then, in the fixing device 13, the toner image transferred onto the paper P is heated by the heating roller R <b> 1 and is pressed by the pressure roller R <b> 2 to be fixed on the paper P.

  Two or more, for example, four image forming units 20 are arranged in the horizontal direction, and toner images of different colors such as black, yellow, magenta, and cyan are formed in each image forming unit. A color image can be formed.

  Next, the operation of the printer 10 having the above configuration will be described.

  The sheets P stored in the sheet cassette 91 are separated and fed out one by one by the hopping roller 15a, and are conveyed along the medium conveyance path. Then, after the skew is corrected by the registration roller 15b, the toner image on the photosensitive drum 23 is transferred to the paper P at the transfer portion. The paper P to which the toner image has been transferred is sent to the fixing device 13, where the toner image is heated, pressurized, and fixed on the paper P. Thereafter, the paper P is discharged out of the apparatus main body by the discharge roller 15c.

  Next, the toner 31 will be described.

  The toner 31 used in the present embodiment is a non-magnetic one-component negatively chargeable toner produced by a pulverization method, using a polyester resin as a binder (binder resin), and a colorant in the binder, A base toner (toner mother particles) is formed by dispersing a charge control agent or the like, and an external additive for adjusting fluidity and chargeability is added to the base toner.

  Examples of the colorant include carbon black, copper phthalocyanine pigment (CI Pigment Blue 15), quinacridone pigment (CI Pigment Red 22), C.I. I. Pigment Yellow 185 or the like is used, and as the additive, for example, titanium oxide, alumina, silica, or the like is used. Further, as silica, those subjected to silicone oil treatment, disilazane treatment and the like are used.

  The volume average particle diameter of the toner 31 is 5.7 [μm], the circularity is 0.92, and the blow-off charge amount is −36 [μC / g]. For measuring the volume average particle diameter, Coulter Multiplier II (manufactured by Coulter) was used. For measuring the circularity, a flow type particle image analyzer FPIA-3000 (manufactured by Sysmex Corporation) was used. For the measurement, a powder charge amount measuring device TYPE TB-203 (manufactured by Kyocera Corporation) was used. In the measurement of the blow-off charge amount, the toner 0.5 [g] and ferrite carrier (F-60) (manufactured by Powdertech Co., Ltd.) 9.5 [g] are mixed and stirred for 30 [min]. The saturated charge amount was measured under the conditions of a blow pressure of 7.0 [kPa] and a suction pressure of -4.5 [kPa].

  Next, the developing roller 21 will be described.

  FIG. 4 is a sectional view of the developing roller in the first embodiment of the present invention.

  As shown in the figure, the developing roller 21 is made of a conductive metal, in the present embodiment, a stainless steel (SUS) metal core 21a, and an elastic body formed on the metal core 21a. An elastic layer 21b, and a semiconductive resin film 21c formed on the elastic layer 21b. The semiconductive resin film 21c is made of an acrylic resin and carbon black in consideration of charge imparting property to the toner 31. Etc. are dispersed.

  As the material of the elastic layer 21b, a general rubber material such as silicone rubber and urethane rubber can be used. In the present embodiment, silicone rubber is used.

  Further, the rubber hardness of the elastic layer 21b is suitably in the range of 50 [°] or more and 80 [°] or less in Asker C hardness, and in this embodiment, the Asker C hardness is 60 [°]. It was.

  Next, the developing blade 26 will be described.

  The developing blade 26 is made of a metal having elasticity, in this embodiment, stainless steel (SUS), and has a plate thickness of 0.08 [mm]. The bending radius R of the bent portion was 0.18 [mm], and the linear pressure against the developing roller 21 at the contact portion was 35 [gf / cm].

  In consideration of the linear pressure of the developing blade 26, the surface roughness and resistance value of the developing roller 21 are set in order to set the layer thickness and the charge amount of the toner 31 on the developing roller 21 to predetermined values. .

  In the present embodiment, the ten-point average roughness Rz (JIS B0601-1994) of the surface of the developing roller 21 is 2 to 8 [μm]. The surface roughness was measured with Surfcoder SEF3500 (manufactured by Kosaka Laboratories), the stylus radius of the measuring device was 2 [μm], the stylus pressure was 0.7 [mN], and the stylus feed speed The thickness was set to 0.1 [mm / sec].

Further, the resistance value of the developing roller 21 is in the range of 1 × 10 ⁶ [Ω] or more and 1 × 10 ⁹ [Ω] or less including the elastic layer 21b and the semiconductive resin film 21c.

  Next, a method for measuring the resistance value of the developing roller 21 will be described.

  FIG. 5 is a first conceptual diagram showing a developing roller resistance value measuring device according to the first embodiment of the present invention, and FIG. 6 is a developing roller resistance value measuring device according to the first embodiment of the present invention. It is the 2nd conceptual diagram which shows.

  In measuring the resistance value of the developing roller 21, a high resistance meter (model number: 4339B) (manufactured by Hewlett-Packard Company) 51 was used as a measuring device. Stainless steel ball bearings 52a to 52f having a width of 2.0 [mm] and a diameter of 6.0 [mm] are contacted at six locations in the axial direction of the developing roller 21 with a force of 20 [gf]. Then, a DC voltage of 100 [V] was applied to the developing roller 21, the developing roller 21 was rotated at a speed of 50 [rpm], and the resistance value between the cored bar 21a and the roller surface was measured.

  For each ball bearing 52a to 52f, while the developing roller 21 is rotated once, the resistance value is measured at 100 points on the circumference, the resistance value is measured at a total of 600 points, and the resistance value at each point is measured. The average value was used as the resistance value of the developing roller 21.

  Next, the toner supply brush roller 22 will be described.

  As described above, the toner supply brush roller 22 is made of a conductive metal brush 22b formed of a fabric woven with conductive fibers adjusted to a desired resistance value. Is formed by spirally winding around a stainless steel cored bar 22a.

The resistance value of the toner supply brush roller 22 was measured by a high resistance meter 51 shown in FIGS. The resistance value is preferably in the range of 1 × 10 ⁶ [Ω] or more and 1 × 10 ¹⁰ [Ω] or less when a DC voltage of 50 [V] is applied to the toner supply brush roller 22. .

Further, the length of the yarn of the brush 22b was 3 [mm], the fineness (thickness) was 6 [denier], and the planting density was 80 [kF / inch ² ]. Further, as the material of the brush 22b, in the present embodiment, a non-magnetic one-component negatively chargeable toner is used as the toner 31. It is preferable to use nylon (registered trademark), acrylic, or the like located on the charging side, and in this embodiment, nylon fiber (registered trademark) (UUN material manufactured by Unitika Ltd.) was used.

  Next, the toner supply brush flicker 27 will be described.

  The toner supply brush flicker 27 is formed by a cylindrical bar made of stainless steel having a cross-sectional diameter of 3 mm. The toner supply brush flicker 27 can be formed of a metal plate having a thickness of about 0.5 mm. When the metal plate is used as the toner supply brush flicker 27, the metal plate Since the brush 22b of the toner supply brush roller 22 is easily worn by the edge, the bent portion is formed on the tip of the metal plate so that the bent portion is brought into contact with the toner supply brush roller 22. Is preferred.

  Next, the toner collection brush roller 25 will be described.

  As described above, the toner recovery brush roller 25 spirals a brush 25b formed of a fabric woven with conductive fibers adjusted to a desired resistance value on a conductive metal core 25a. It is formed by wrapping in a shape.

The resistance value of the toner supply brush roller 25 was measured by a high resistance meter 51 shown in FIGS. The resistance value is preferably in the range of 1 × 10 ⁶ [Ω] or more and 1 × 10 ⁸ [Ω] or less when a DC voltage of 50 [V] is applied to the toner recovery brush roller 25. . When the resistance value of the toner recovery brush roller 25 is higher than 1 × 10 ⁸ [Ω], the charge is accumulated in the brush 25b, and the charge before developing on the developing roller 21, that is, the charge of undeveloped toner It cannot be removed.

In addition, the length of the yarn of the brush 25b was 3 [mm], the fineness was 6 [denier], and the planting density was 75 [kF / inch < ² >]. Further, as the material of the brush 22b, in the present embodiment, a non-magnetic one-component negatively chargeable toner is used as the toner 31. It is preferable to use nylon (registered trademark), acrylic, or the like located on the charging side. In this embodiment, acrylic (SA-7 material manufactured by Toray Industries, Inc.) was used.

  Next, the toner recovery brush flicker 28 will be described.

  The toner recovery brush flicker 28 is formed of a cylindrical bar made of stainless steel having a cross-sectional diameter of 3 mm. The toner recovery brush flicker 28 can be formed of a metal plate having a thickness of about 0.1 mm. However, when the metal plate is used as the toner recovery brush flicker 28, the metal plate Since the edge of the brush 25b of the toner collecting brush roller 25 is easily worn by the edge, the bent portion is formed by bending the front end portion of the metal plate, and the bent portion is brought into contact with the toner collecting brush roller 25. Is preferred.

  Next, the auxiliary supply roller 30 will be described.

  As described above, the auxiliary supply roller 30 includes the core metal 30a and the silicone rubber sponge layer 30b formed on the core metal 30a. The silicone rubber sponge layer 30b is formed by molding an unvulcanized silicone rubber compound by a method such as extrusion and vulcanizing and foaming by heating.

  In the present embodiment, the auxiliary supply roller 30 is used in which a cell having fine holes is formed on the surface by foaming a silicone rubber compound. The diameter of each hole in the cell is 200 [μm] or more and 500 [μm] or less, and the Asker F hardness of the auxiliary supply roller 30 is 50 [°] or more and 80 [°] or less. It was made the range.

  The silicone rubber compound is formed by adding a reinforcing silica filler, a vulcanizing agent necessary for vulcanization and a foaming agent, to various raw rubbers such as dimethyl silicone raw rubber and methylphenyl silicone raw rubber. As the foaming agent, an inorganic foaming agent such as sodium bicarbonate, an organic foaming agent such as ADCA, or the like is used. When the silicone rubber sponge layer 30b is semiconductive, acetylene black or carbon black is added to the raw rubber. Furthermore, the hardness of the auxiliary supply roller 30 can be adjusted by changing the addition amount of the vulcanizing agent.

  Next, a level signal generator for detecting the toner level in the casing Cs2 will be described.

  FIG. 7 is a conceptual diagram of the level signal generator according to the first embodiment of the present invention, FIG. 8 is a perspective view showing the main part of the level signal generator according to the first embodiment of the present invention, and FIG. It is a figure for demonstrating the detection state of the reflecting plate by the photon detection part in the 1st Embodiment of invention. FIG. 9 is a view of the light detection unit Ha and the reflection plate 62 in FIG. 7 as viewed from the gear gr1 side.

  In the figure, reference numeral 60 denotes a level signal generator, which is connected to a drive motor (M) 17 as a drive source for rotating the photosensitive drum 23 via a gear train (not shown). , A gear gr1 as a rotation transmission member that is rotated at a constant rotation speed, and a rotation transmission unit 61 as a rotation transmission member that is rotated along with the rotation of the gear gr1 and transmits the rotation of the gear gr1 to the detection lever 34; The detection lever 34 that receives the rotation of the gear gr1 through the rotation transmission unit 61 and is rotated intermittently, the reflection plate 62 as a detected element attached to the detection lever 34, and a light detection unit as a detection element A signal representing the toner level in the casing Cs2, that is, a level signal is generated.

  The rotation transmission unit 61 has a rotating body 61a fixed to the output shaft sh0 of the gear gr1 and an L-shaped shape, and is formed on the driving side formed by projecting from the rotating body 61a into the casing Cs2. A protrusion 61b is provided as a locking portion. The output shaft sh0 is rotatably supported by a bearing (not shown) disposed in the casing Cs2.

  In addition, as described above, the detection lever 34 is formed of a crank-shaped metal bar, and the rotation shaft portions sh1 and sh2 serving as the rotation centers of the detection lever 34 are disposed at both ends between the rotation shaft portions sh1 and sh2. The rotation shaft portions sh1 and sh2 are provided with an arm portion m as a driven-side engaging portion between the rotation shaft portions sh1 and sh2 and the rotation shaft portion sh3.

  The rotation shaft portion sh1 is relatively rotatably fitted in a hole formed at the rotation center of the rotating body 61a. The rotation shaft portion sh2 extends through the casing Cs2 and has the reflection plate 62 at the tip. Is attached. The reflecting plate 62 is preferably capable of reflecting laser light as detection light. In the present embodiment, a mirror is used as the reflecting plate 62.

  Therefore, the detection lever 34 is directly disposed on the casing Cs2 on the rotating shaft sh2 side by the bearing disposed on the casing Cs2 via the rotation transmission unit 61 on the rotating shaft sh1 side. It is supported rotatably by a non-supported bearing.

  When the rotation of the drive motor 17 is transmitted to the gear gr1, the rotation transmission unit 61 is rotated in the direction of the arrow re at a predetermined rotational speed, the projection 61b hits the arm portion m, and the arm portion m is pressed. 34 can be rotated to rotate the reflector 62. Then, when the turning shaft portion sh3 of the detection lever 34 reaches the highest position of the rotation trajectory Cr1, that is, the apex pU, the turning shaft portion sh3 has its own weight toward the lowest position of the rotation trajectory Cr1, ie, the bottom point pL. You can fall and swivel. The rotation speed of the gear gr1 is set lower than the rotation speed of the detection lever 34 when the detection lever 34 is swung by its own weight from the apex pU of the rotation track Cr1 toward the bottom point pL.

  The light detection unit Ha is disposed to face the reflecting plate 62, and the light emitting element 63 as a first detector that emits the laser light 63a, and the laser light 63a reflected by the reflecting plate 62. Is provided with a light receiving element 64 as a second detector for receiving light. The light receiving element 64 generates the level signal as a sensor output, and the light receiving element 64 constitutes a level sensor as a level signal generating element.

  In the present embodiment, the position of the light detection unit Ha is the light receiving element 64 using the laser light 63a emitted by the light emitting element 63 when the reflecting plate 62 is positioned at the intermediate point pM between the apex pU and the bottom point pL. Is set to receive light.

  As shown in FIG. 9, the laser beam 63a of the light emitting element 63 passes through the intermediate point pM until the reflecting plate 62 moves to the bottom point pL after passing through the apex pU of the rotation orbit Cr1 of the detection lever 34. The reflective plate 62 is irradiated only during this time. And while the reflecting plate 62 passes the intermediate point pM, the light receiving element 64 receives the laser beam 63a. In this case, when the light receiving element 64 receives the laser beam 63a, the level signal is turned on, and when the laser beam 63a is not received, the level signal is turned off.

  Next, the operation of the level signal generator 60 will be described.

  FIG. 10 is a first diagram illustrating the operation of the level signal generating apparatus according to the first embodiment of the present invention, and FIG. 11 is a second diagram illustrating the operation of the level signal generating apparatus according to the first embodiment of the present invention. FIG.

  As shown in FIG. 10, when the upper surface 31 a of the toner 31 is located above the apex pU of the rotation track Cr <b> 1 of the detection lever 34 and the rotation track Cr <b> 1 is buried in the toner 31, The portion sh3 is always pushed by the protrusion 61b of the rotation transmission unit 61, and the detection lever 34 is rotated at the same rotational speed as the rotation transmission unit 61.

  Then, as shown in FIG. 11, when the upper surface 31a of the toner 31 is located below the apex pU of the rotation trajectory Cr1 of the detection lever 34 and a part of the rotation trajectory Cr1 is buried in the toner 31, When the turning shaft sh3 reaches the apex pU of the rotation track Cr1 with the rotation of the transmission unit 61, the toner 31 does not exist in a predetermined section on the rotation track Cr1, so the turning shaft portion sh3 has its own weight and the upper surface 31a. It drops to a height and is stopped by the resistance force of the toner 31 at the height of the upper surface 31a. When the rotation shaft unit sh3 is pushed by the protrusion 61b as the rotation transmission unit 61 rotates, the detection lever 34 is rotated at the same rotational speed as the rotation transmission unit 61.

  Next, regarding the relationship between the toner level and the time during which the light receiving element 64 is on when the reflecting plate 62 passes the intermediate point pM on the rotation trajectory Cr1, that is, the time during which the light receiving element 64 receives the laser light 63a. explain. The light reception time is used as a detection index for detecting the toner level.

  FIG. 12 is a relationship diagram between the toner level and the light receiving time in the first embodiment of the present invention. In the figure, the horizontal axis represents the toner level, and the vertical axis represents the light receiving time T.

  As shown in the figure, when the toner level is higher than the intermediate point pM of the rotation trajectory Cr1 of the detection lever 34, the rotational speed when the reflecting plate 62 passes through the intermediate point pM is equal to the rotational speed of the gear gr1. At this time, the light receiving time T of the laser light 63a by the light receiving element 64 becomes a value T1 as the first threshold value.

  When the toner level is lower than the intermediate point pM of the rotation trajectory Cr1 of the detection lever 34, the rotation speed when the reflecting plate 62 passes through the intermediate point pM is the detection lever 34 when the turning shaft portion sh3 falls by its own weight. And the toner level is higher than the rotation speed when the reflector 62 passes through the intermediate point pM when the toner level is higher than the intermediate point pM of the rotation trajectory Cr1 of the detection lever 34.

  Accordingly, the light receiving time T at this time becomes a value T2 as a second threshold value shorter than the value T1.

  When the toner level is equal to the intermediate point pM of the rotation trajectory Cr1 of the detection lever 34, the light receiving element 64 continues to be turned on until the turning shaft portion sh3 is pushed by the protrusion 61b. T3.

  Next, the control device of the printer 10 will be described.

  FIG. 13 is a control block diagram of the printer according to the first embodiment of the present invention.

  In the figure, reference numeral 70 denotes a print control unit as a first control unit configured by a microprocessor, ROM, RAM, input / output port, timer, and the like. The print data and control command are received, the entire sequence of the printer 10 is controlled, and the printing operation is performed. The ROM constitutes a first recording device, the RAM constitutes a second recording device, and a timer constitutes a time measuring element.

  Reference numeral 72 denotes a reception memory as a recording unit for temporarily recording print data input from the host computer via the interface control unit 71. Reference numeral 73 denotes the print data recorded in the reception memory 72 and the print data. It is an image data editing memory as a recording unit for recording image data formed by editing data, that is, image data.

  An operation 74 includes an LED (not shown) as a display element for displaying the status of the printer 10, and a switch, a key (not shown) as an operation element for an operator to input an instruction to the printer 10. , 75 is a sensor group. The sensor group 75 is a sensor for monitoring the operation state of the printer 10, for example, a sheet position detection sensor as a medium detection unit for detecting the position of the sheet P, and the printer 10. , A temperature / humidity sensor as an environment detection unit for detecting temperature, humidity, etc., a print density sensor as a density detection unit for detecting print density, and the remaining amount of toner 31 in the toner cartridge 32 are detected. And a toner remaining amount sensor as a developer remaining amount detecting unit.

  Further, 63 is a light emitting element, 64 is a light receiving element, and 86 is a timer as a time measuring member for measuring the light receiving time T. The timer 86 reads the level signal of the light receiving element 64, starts measuring when the light receiving element 64 is turned on, ends measuring when the light receiving element 64 is turned off, and measures the light receiving time T.

  Reference numeral 76 denotes a charging power source as a first power source. The charging power source 76 applies a predetermined DC voltage to the charging roller 24 according to an instruction from the print control unit 70 to charge the surface of the photosensitive drum 23. . Reference numeral 77 denotes a developing power source as a second power source. The developing power source 77 applies a predetermined DC voltage to the developing roller 21 to attach the toner 31 to the electrostatic latent image. Reference numeral 78 denotes a supply power supply as a third power supply. The supply power supply 78 applies a predetermined DC voltage to the toner supply brush roller 22 and supplies the toner 31 to the developing roller 21. Reference numeral 79 denotes a recovery power source serving as a fourth power source. The recovery power source 79 applies a predetermined DC voltage to the toner recovery brush roller 25 to recover the toner 31 from the developing roller 21. Reference numeral 80 denotes a transfer power source as a fifth power source. The transfer power source 80 applies a predetermined DC voltage to the transfer roller 12 to transfer the toner image formed on the photosensitive drum 13 to the sheet P. Transcript to.

  The charging power supply 76, the developing power supply 77, the supply power supply 78, the recovery power supply 79, and the transfer power supply 80 can change the DC voltage applied in accordance with an instruction from the print control unit 70. Yes.

  Reference numeral 81 denotes a drive control unit as a second control unit, and the drive control unit 81 drives a drive motor 17 for rotating the photosensitive drum 23. When the drive motor 17 is driven by the drive control unit 81, the photosensitive drum 23 is rotated, and the charging roller 24, the developing roller 21, the toner supply brush roller 22, the toner collection brush roller 25, the auxiliary supply roller 30, The stirring members 33a to 33d and the detection lever 34 are rotated.

  Reference numeral 82 denotes a head drive control unit serving as a third control unit. The head drive control unit 82 sends the image data recorded in the image data editing memory 73 to the LED head 11 to drive the LED head 11. To do. Reference numeral 83 denotes a fixing control unit as a fourth control unit. The fixing control unit 83 applies a DC voltage to the fixing device 13 to fix the transferred toner image on the paper P. The fixing device 13 includes a temperature sensor (not shown) as a fixing temperature detection unit that detects the temperature of the heating roller R1, and the fixing control unit 83 reads the sensor output of the temperature sensor, and based on the sensor output, the heater And the fixing device 13 is controlled so as to have a constant temperature.

  Reference numeral 84 denotes a conveyance control unit as a fifth control unit. The conveyance control unit 84 drives the paper conveyance motor 16 as a conveyance drive unit to convey the paper P, and the print control unit. In response to the instruction 70, the hopping roller 15a, the registration roller 15b, the discharge roller 15c, and the like are rotated, and the paper P is conveyed or stopped at a predetermined timing.

  Reference numeral 85 denotes a shutter drive control unit serving as a sixth control unit. The shutter drive control unit 85 opens and closes the shutter 32a according to the toner level, and supplies the toner 31 in the toner cartridge 32 into the casing Cs2. Or stop the supply.

  By the way, when the toner level is equal to or lower than the rotation axis of the auxiliary supply roller 30, the amount of toner 31 held by the auxiliary supply roller 30 when the auxiliary supply roller 30 is rotated is reduced. Further, when the toner level is equal to or higher than the lower end (contact facing portion β1) of the brush 22b of the toner supply brush roller 22, at least a part of the toner supply brush roller 22 is buried in the toner 31, and the toner 31 enters the gap of the brush 22b. It ’s clogged up.

  Accordingly, when the printer 10 is used for a long period of time, the elasticity of the brush 22b is lowered, and the toner 31 cannot be stably supplied to the developing roller 21. As a result, the image quality is degraded.

  Therefore, in the present embodiment, the rotation shafts sh1 and sh2 of the detection lever 34 are higher than the rotation shaft of the auxiliary supply roller 30 and lower than the lower end of the brush 22b of the toner supply brush roller 22, and the print control unit. 70 sends an instruction to the shutter drive controller 85, and the shutter level is such that the toner level in the casing Cs2 is higher than the rotational axis of the auxiliary supply roller 30 and lower than the lower end of the brush 22b of the toner supply brush roller 22. Open and close 32a. In this case, the lower end of the brush 22b of the toner supply brush roller 22 refers to the lower end of the brush 22b in a state where no nip is formed between the toner supply brush roller 22 and the auxiliary supply roller 30.

  Next, the operation of the print control unit 70 for opening and closing the shutter 32a will be described.

  FIG. 14 is a flowchart showing the operation of the print control unit in the first embodiment of the present invention.

  First, a print processing unit (not shown) of the print control unit 70 performs a print process and starts a printing operation by the image forming unit 20, and then a toner level as a developer level detection processing unit (not shown) of the print control unit 70. The detection processing means performs toner level detection processing as developer level detection processing, and reads the light reception time T measured by the timer 86.

  Incidentally, since the position of the intermediate point pM of the rotation trajectory Cr1 of the detection lever 34 and the position of the rotation shafts sh1 and sh2 of the detection lever 34 are equal, the rotation shafts sh1 and sh2 of the detection lever 34 are connected to the auxiliary supply roller 30. When it is higher than the rotation axis and lower than the lower end of the brush 22b of the toner supply brush roller 22, the intermediate point pM of the rotation path Cr1 of the detection lever 34 is also higher than the rotation axis of the auxiliary supply roller 30 and the toner supply brush. Lower than the lower end of the brush 22b of the roller 22.

  As described above, when the toner level is lower than the intermediate point pM, the light reception time T becomes the value T2, and when the toner level is equal to or higher than the intermediate point pM, the light reception time T becomes the value T1, so the toner level Is lower than the rotation shaft portions sh1 and sh2, the light reception time T is a value T2, and when the toner level is greater than or equal to the rotation shaft portions sh1 and sh2, the light reception time T is a value T1.

  Therefore, in the present embodiment, when the toner level becomes lower than the rotation shaft portions sh1 and sh2 and the light receiving time T becomes equal to the value T2, the toner 31 in the toner cartridge 32 is supplied into the casing Cs2, When the toner level becomes equal to or higher than the rotation shafts sh1 and sh2 and the light receiving time T reaches the value T1, the supply of the toner 31 in the toner cartridge 32 into the casing Cs2 is stopped.

  For this purpose, a toner level determination processing unit as a developer level determination processing unit (not shown) of the print control unit 70 performs a toner level determination process as a developer level determination process, and whether or not the light receiving time T is longer than the value T2 ( Whether or not the toner level is greater than or equal to the rotational shafts sh1 and sh2 is determined based on whether or not the actual value is T1.

  When the light receiving time T is longer than the value T2 (actually the value T1) and the toner level is equal to or greater than the rotation shafts sh1 and sh2, the print processing unit continues the printing operation. In this case, the shutter 32a is kept closed.

  Further, when the light receiving time T is equal to or shorter than the value T2 (actually the value T2) and the toner level is lower than the rotation shaft portions sh1 and sh2, a toner supply processing unit as a developer supply processing unit (not shown) of the print control unit 70. Performs toner supply processing as developer supply processing, sends an instruction to the shutter drive control unit 85, and opens the shutter 32a. As a result, the toner 31 in the toner cartridge 32 is supplied into the casing Cs2.

  Then, the toner level determination processing means again determines whether the toner level is equal to or greater than the rotation shaft portions sh1, sh2 depending on whether the light receiving time T is longer than the value T2 (actually, whether it is the value T1). When the light receiving time T becomes longer than the value T2 (actually becomes the value T1) and the toner level becomes equal to or higher than the rotation shafts sh1 and sh2, the toner supply processing means sends an instruction to the shutter drive control unit 85 and the shutter 32a. Close. As a result, the supply of the toner 31 in the toner cartridge 32 into the casing Cs2 is stopped.

Next, a flowchart will be described.
Step S1: A printing operation is started.
Step S2 The system waits for the light receiving time T to become shorter than the light receiving time T2, and proceeds to step S3 when the light receiving time T becomes shorter than the light receiving time T2.
Step S3 Open the shutter 32a.
Step S4 Wait until the light receiving time T becomes longer than the light receiving time T2, and if the light receiving time T becomes longer than the light receiving time T2, the process proceeds to step S5.
Step S5: The shutter 32a is closed, and the process returns to Step S1.

  Next, it was evaluated whether or not the image quality was lowered when printing was continuously performed using the printer 10 having the above-described configuration.

  For this purpose, the printer 10 is placed in an environment of normal temperature and humidity with a temperature of 20 ° C. and a humidity (relative humidity) of 50%, and printing with a blank sheet pattern (hereinafter referred to as “blank sheet printing”) is repeated. A test, i.e., a continuous printing test is performed, and then the toner 31 enters the developing roller 21 to see if a sufficient amount of toner 31 is supplied, i.e., the supply state of the toner 31 and the gap between the brushes 22b. Whether the toner 31 is clogged is determined. In white paper printing, exposure by the LED head 11 is not performed, and no DC voltage is applied to the developing roller 21 by the developing power source 77, so the toner 31 on the developing roller 21 is attached to the photosensitive drum 23. Development is not performed.

  In this case, in order to determine the supply state of the toner 31, every time a predetermined number of blank pages are printed in the continuous print test, the level of blurring generated in the image when 100% duty solid printing is performed. That is, it was determined whether or not whitening occurred. When no white spots have occurred, it is determined that a sufficient amount of toner 31 has been supplied to the developing roller 21, and when white spots have occurred, a sufficient amount of toner 31 has been supplied to the developing roller 21. Judged not to be supplied.

  Further, in order to determine the clogged state of the toner 31, a continuous printing test was performed, and the Asker F hardness of the toner supply brush roller 22 was measured when solid printing was performed every time a predetermined blank sheet was printed. Then, it was determined that the higher the Asker F hardness, the more the toner 31 enters the gap between the brushes 22b and the toner 22 is clogged.

  In the continuous printing test, the developing power supply 77 applies a DC voltage of −200 [V] to the developing roller 21 and the developing blade 26, and the supplying power supply 78 applies −1500 to the toner supply brush roller 22 and the auxiliary supply roller 30. A DC voltage of [V] was applied. Further, the toner recovery brush roller 25 is grounded.

  The image forming unit 20 of the present embodiment is taken as Example 1, the image forming unit 20 as shown in FIG. 15 is set as Comparative Example 1, and the image forming unit 20 as shown in FIG. The supply state and clogging state of the toner 31 were determined for Example 1 and Comparative Examples 1 and 2.

  FIG. 15 is a schematic diagram of the image forming unit of Comparative Example 1, FIG. 16 is a schematic diagram of the image forming unit of Comparative Example 2, and FIG. 17 is a continuation by the image forming unit of Comparative Example 1 in the first embodiment of the invention. FIG. 18 is a diagram showing the toner level after the printing test, and FIG. 18 is a diagram showing the toner level after the continuous printing test by the image forming unit of Comparative Example 2 in the first embodiment of the present invention.

  In FIG. 15, reference numeral 20 denotes an image forming unit of Comparative Example 1. In the image forming unit 20, the toner supply brush roller 92 is opposed to the developing roller 21 below the developing roller 21, and the developing roller 21 (without contact) 21 is rotatably arranged in the direction of the arrow h (the direction opposite to the direction of the arrow e in the first embodiment), and the auxiliary supply roller 93 is below the toner supply brush roller 92. The toner supply brush roller 92 is opposed to the toner supply brush roller 92 and is in contact with the toner supply brush roller 92 so as to be rotatable in the direction of arrow i (the direction opposite to the arrow g direction in the first embodiment). The toner supply brush roller 92 includes a metal core 92a and a brush 92b. Therefore, the toner supply brush flicker 97 is disposed upstream of the developing roller 21 in the rotation direction of the toner supply brush roller 92.

  In FIG. 16, reference numeral 20 denotes an image forming unit of Comparative Example 2. In the image forming unit 20, the auxiliary supply roller in Example 1 is not disposed.

  Next, the determination result of the supply state and clogging state of the toner 31 when the continuous printing test of 30000 sheets is performed in the image forming unit 20 of the first embodiment and the comparative examples 1 and 2 will be described.

  Table 1 shows the determination result of the supply state of the toner 31 at the initial stage in the continuous printing test, after 500 sheets of blank paper, 1000 sheets, 5000 sheets, 10000 sheets, 20000 sheets, and 30000 sheets. ○ indicates that no white spots have occurred, and x indicates that white spots have occurred.

  Table 2 shows the determination result of the clogged state of the toner 31 at the initial stage in the continuous printing test, after 500 sheets of blank paper, 1000 sheets, 5000 sheets, 10000 sheets, 20000 sheets, and 30000 sheets. When the Asker F hardness is less than 95, it indicates that the toner 31 is not clogged in the gap of the brush 22b, and when it is 95 or more, it indicates that the toner 31 is clogged in the gap of the brush 22b.

  In the image forming unit 20 of Example 1, white spots did not occur even after 30000 sheets, and the toner 31 did not clog the gap between the brushes 22b.

  In contrast, in the image forming unit 20 of Comparative Example 1, white spots occurred after 20000 sheets, and the toner 31 was clogged in the gap between the brushes 922b. Further, in the image forming unit 20 of Comparative Example 2, white spots occurred after 5000 sheets, and the toner 31 was clogged in the gap between the brushes 22b.

  In the image forming unit 20 of Example 1, the toner level after 30000 sheets is set to the same state as before the start of the continuous printing test, whereas in the image forming unit 20 of Comparative Example 1, 20000 is set. After the sheets, the toner 31 is clogged in the gap between the brushes 92b, and the toner supply brush roller 92 cannot supply a sufficient amount of toner 31 to the developing roller 21. Accordingly, the toner 31 is no longer supplied from the auxiliary supply roller 93 to the toner supply brush roller 92, and as the auxiliary supply roller 93 is rotated in the arrow i direction, the toner 31 that is not supplied to the toner supply brush roller 92 is supplied. Then, it passes between the auxiliary supply roller 93 and the toner supply brush roller 92 and is supplied to the toner collection brush roller 25 side. As a result, as shown in FIG. 17, the area on the detection lever 34 side from the toner supply brush roller 92 in the casing Cs2 is set as the first area, and the area on the toner collection brush roller 25 side from the toner supply brush roller 92 is set as the first area. When the second area is set, the toner level in the second area is higher than the toner level in the first area.

  As a result, the toner supply brush roller 92 is buried in the toner 31, and the toner 31 is further clogged in the gap between the brushes 92 b, so that a sufficient amount of toner 31 cannot be supplied to the developing roller 21. Further, since the toner collecting brush roller 25 is buried in the toner 31 and the toner 31 is clogged in the gap between the brushes 25b, the toner 31 on the developing roller 21 cannot be sufficiently collected.

  In the image forming unit 20 of Comparative Example 2, a part of the toner supply brush roller 22 is buried in the toner 31 in the initial state after 5000 sheets, so that the toner 31 is easily clogged in the gap of the brush 22b, and the toner supply brush A sufficient amount of toner 31 cannot be supplied to the developing roller 21 by the roller 22. Accordingly, as the toner supply brush roller 22 is rotated in the direction of arrow e, the toner 31 that is not supplied to the developing roller 21 passes between the toner supply brush roller 22 and the developing roller 21 and is a toner recovery brush. Supplied to the roller 25 side. As a result, as shown in FIG. 18, the area on the detection lever 34 side from the toner supply brush roller 22 in the casing Cs2 is set as the first area, and the area on the toner collection brush roller 25 side from the toner supply brush roller 22 is set as the first area. When the second area is set, the toner level in the second area is higher than the toner level in the first area.

  As a result, the toner supply brush roller 22 is further buried in the toner 31, and the toner 31 is further clogged in the gap between the brushes 22 b, so that a sufficient amount of toner 31 cannot be supplied to the developing roller 21. Further, since the toner collecting brush roller 25 is buried in the toner 31 and the toner 31 is clogged in the gap between the brushes 25b, the toner 31 on the developing roller 21 cannot be sufficiently collected.

  Thus, in the present embodiment, the auxiliary supply roller 30 is disposed below the toner supply brush roller 22 so as to be in contact with the toner supply brush roller 22, and the rotation shaft portions sh1 and sh2 of the detection lever 34 are Since it is lower than the lower end of the brush 22 b of the toner supply brush roller 22, the toner supply brush roller 22 can be lifted from the toner 31.

  Therefore, the brush 22b is not buried in the toner 31 and the toner 31 can be prevented from entering and clogging into the gap of the brush 22b, so that the elasticity of the brush 22b is not lowered, and the toner 31 is stabilized on the developing roller 21. Can be supplied.

  In addition, since the toner supply brush roller 22 is rotated in the same direction as the developing roller 21 and the auxiliary supply roller 30 is rotated in the opposite direction to the developing roller 21, the toner 31 enters the gap between the brushes 22b and is further clogged. Can be suppressed.

  Further, since the rotation shafts sh1 and sh2 of the detection lever 34 are placed above the rotation shaft of the auxiliary supply roller 30, the auxiliary supply roller 30 holds a sufficient amount of toner 31 when the auxiliary supply roller 30 is rotated. A sufficient amount of toner 31 can be supplied to the developing roller 21.

  As a result, it is possible to prevent the image quality from deteriorating.

  Next, a second embodiment of the present invention will be described. In addition, about the thing which has the same structure as 1st Embodiment, the same code | symbol is provided and the effect of the same embodiment is used about the effect of the invention by having the same structure.

  FIG. 19 is a schematic diagram of an image forming unit according to the second embodiment of the present invention.

  In the figure, reference numeral 22 denotes a first supply which is disposed so as to face a developing roller 21 as a developer carrying member and to rotate freely in the direction of an arrow e without contacting the developing roller 21 (without contact). A toner supply brush roller 117 as a member and a brush roller (developer supply brush roller) is opposed to the toner supply brush roller 22 above the toner supply brush roller 22 and is a toner supply brush. A toner supply brush flicker as a developer flying member disposed in contact with the roller 22 so as to be rotatable in the direction of an arrow j. The nip amount d2 between the toner supply brush roller 22 and the toner supply brush flicker 117 is set to 0.5 [mm] as in the first embodiment.

  A gear (not shown) is attached to one end of the toner supply brush flicker 117 outside the casing Cs2 as a casing, and the gear and a drive motor 17 (FIG. 7) as a drive source are connected via a gear train (not shown). The gears are connected and rotated at a constant rotation speed, and the rotation is transmitted to the toner supply brush flicker 117.

  In this embodiment, the peripheral speed of the toner supply brush flicker 117 and the peripheral speed of the toner supply brush roller 22 are equalized.

  Therefore, sliding between the surface of the toner supply brush flicker 117 and the tip of the brush 22b of the toner supply brush roller 22 can be suppressed, so that the wear of the brush 22b can be suppressed. Although the peripheral speed of the toner supply brush flicker 117 and the peripheral speed of the toner supply brush roller 22 are equalized, a nip is formed between the toner supply brush flicker 117 and the toner supply brush roller 22. The toner supply brush flicker 117 can sufficiently cause the toner 31 as the developer held by the toner supply brush roller 22 to fly toward the development roller 21.

  The printer 10 as an image forming apparatus having the above-described configuration is placed in a high-temperature and high-humidity environment where the temperature is 27 ° C. and the humidity (relative humidity) is 80%, and a continuous printing test is performed. The supply state and clogging state were judged.

  Next, the image forming unit 20 of the first embodiment is referred to as Example 1, the image forming unit 20 of the second embodiment is referred to as Example 2, and in Examples 1 and 2, 30000 sheets are continuously printed. The determination result of the supply state and the clogged state of the toner 31 when the test is performed will be described.

  Table 3 shows the determination of the supply state of the toner 31 in the initial, 500, 1000, 5000, 10000, 20000, and 30,000 sheets of blank paper printing in a continuous printing test in a high temperature and high humidity environment. Results are shown. ○ indicates that no white spots have occurred, and x indicates that white spots have occurred.

  Table 4 shows the clogged state of the toner 31 at the initial stage in the continuous printing test under a high temperature and high humidity environment, after 500 sheets of blank paper, after 1000 sheets, after 5000 sheets, after 10,000 sheets, after 20000 sheets and after 30,000 sheets. The judgment result is shown. When the Asker F hardness is less than 95, it indicates that the toner 31 is not clogged in the gap of the brush 22b, and when it is 95 or more, it indicates that the toner 31 is clogged in the gap of the brush 22b.

  In the image forming unit 20 of Example 2, white spots did not occur even after 30000 sheets, and the toner 31 did not clog the gap between the brushes 22b.

  On the other hand, in the image forming unit 20 of Example 1, the toner 31 was not clogged in the gap between the brushes 22b after 30000 sheets, but white spots occurred.

  Next, a mechanism for causing white spots in the image forming unit 20 of Example 1 under a high temperature and high humidity environment will be described.

  FIG. 20 is a diagram for explaining a mechanism in which white spots occur in the image forming unit 20 according to the first embodiment under a high temperature and high humidity environment.

  As described above, in the image forming unit 20 of the first embodiment, the toner supply brush flicker 27 is disposed on the vertical line La of the contact portion between the developing roller 21 and the developing blade 26 as the developer regulating member. Is done. Accordingly, the toner 31 scraped from the developing roller 21 by the developing blade 26 falls onto the toner supply brush flicker 27. In a high-temperature and high-humidity environment, the toner 31 absorbs moisture and has low fluidity, so that the toner 31 is likely to be deposited on the toner supply brush flicker 27.

  The toner 31 flying from the toner supply brush roller 22 in the direction of arrow A forms a toner layer on the developing roller 21. When the toner 31 deposited on the toner supply brush flicker 27 comes into contact with the toner layer, It is considered that the layer thickness of the toner layer on the developing roller 21 before passing through the developing blade 26 decreases, and as a result, white spots occur.

  On the other hand, in the image forming unit 20 of the second embodiment, the toner supply brush flicker 117 is rotated, so that the toner 31 scraped off from the development roller 21 by the developing blade 26 is the toner supply brush flicker 117. Even if the toner drops, the toner 31 can be prevented from being deposited on the flicker 117 for the toner supply brush. Therefore, it is possible to prevent white spots from occurring.

  In the present embodiment, the toner supply brush flicker 117 is rotated to prevent the toner 31 from accumulating on the toner supply brush flicker 117. However, the drive unit is not illustrated. By turning the solenoid on and off, the toner supply brush flicker 117 can be moved in the axial direction, and the toner 31 can be prevented from being deposited on the toner supply brush flicker 117.

  As described above, in the present embodiment, since the toner supply brush flicker 117 is rotated, it is possible to suppress the toner 31 from being deposited on the toner supply brush flicker 117. Accordingly, since a sufficient amount of toner 31 can be supplied to the developing roller 21 even in a high temperature and high humidity environment, it is possible to prevent the image quality from deteriorating.

  Next, a third embodiment of the present invention will be described. In addition, about the thing which has the same structure as 1st, 2nd embodiment, the same code | symbol is provided and the effect of the embodiment is used about the effect of the invention by having the same structure.

  FIG. 21 is a schematic diagram of an image forming unit according to the third embodiment of the present invention.

  In this case, in the image forming unit 20, a toner storage chamber 122 as a developer storage chamber is integrally formed in a casing Cs3 as a casing of the image forming unit main body 20a, and the developer storage chamber 122 is used as a developer. The toner 31 is accommodated.

  Next, a fourth embodiment of the present invention will be described. In addition, about the thing which has the same structure as 1st-3rd embodiment, the same code | symbol is provided and the effect of the same embodiment is used about the effect of the invention by having the same structure.

  FIG. 22 is a conceptual diagram of a printer according to the fourth embodiment of the present invention.

  As shown in the drawing, a printer 130 as an image forming apparatus includes image forming units 135Bk, 135Y, 135M, and 135C for each toner as developer of four colors of black, yellow, magenta, and cyan. The units 135Bk, 135Y, 135M, and 135C include a photosensitive drum 23 as an image carrier. Then, an LED head 11 as an exposure device is disposed so as to face the photosensitive drum 23, and an electrostatic latent image as a latent image is formed on the photosensitive drum 23 by the LED head 11, and a developer carrier. The electrostatic latent image is developed by a developing roller (not shown) as a toner image as a developer image of each color.

  A transfer unit u1 is disposed along the image forming units 135Bk, 135Y, 135M, and 135C. The transfer unit u 1 includes a driving roller r 11, a driven roller r 12, a transfer belt 123 that is stretched between the driving roller r 11 and the driven roller r 12, and runs in the direction of the arrow, and each photoconductor via the transfer belt 123. A transfer roller 124 as a transfer member brought into contact with the drum 23 is provided.

  In this case, toner images of the respective colors are formed in the image forming units 135Bk, 135Y, 135M, and 135C, and the paper P as a medium is moved to the image forming units 135Bk, 135Y, 135M, and 135C as the transfer belt 123 travels. After passing between the transfer rollers 124, the toner images on the photosensitive drums 23 are sequentially superimposed and transferred onto the paper P to form a color toner image.

  Subsequently, the paper P is sent to a fixing device 13 as a fixing device, and the color toner image is fixed on the paper P in the fixing device 13.

  Next, the image forming units 135Bk, 135Y, 135M, and 135C will be described. Since the image forming units 135Bk, 135Y, 135M, and 135C have the same structure, only the image forming unit 135Bk will be described.

  FIG. 23 is a schematic diagram of an image forming unit according to the fourth embodiment of the present invention, FIG. 24 is a first enlarged view showing a main part of the image forming unit according to the fourth embodiment of the present invention, and FIG. It is a 2nd enlarged view which shows the principal part of the image forming unit in the 4th Embodiment of this invention.

  As shown in the figure, in the image forming unit 135Bk, a main body of the image forming unit 135Bk, that is, a casing Cs4 as a housing of the image forming unit main body, as a developer holding space and as a developer storage chamber. The toner storage chamber 122 is integrally formed, and the toner 31 as a developer is stored in the toner storage chamber 122.

  In addition, the image forming unit 135Bk is arranged so as to be rotatable in the direction of an arrow c ′ in contact with the photosensitive drum 23, which is arranged to be rotatable in the direction of an arrow a ′. A charging roller 24 as a charging device that uniformly charges the surface of the drum 23 and as a charging member, a developing device 90 for developing the electrostatic latent image to form a toner image, and a tip of the charging drum 24 with the photosensitive drum 23 A cleaning blade 29 serving as a cleaning member that is disposed in contact and collects the toner 31 remaining on the photoconductor drum 23 after transfer, and the photoconductor on the downstream side of the cleaning blade 29 in the rotation direction of the photoconductor drum 23. A neutralization device 145 that is disposed without contacting the drum 23 and resets the charged potential of the photosensitive drum 23 by irradiating the neutralization light is provided.

  The developing device 90 is disposed below the photosensitive drum 23 so as to face the photosensitive drum 23 and to be in contact with the photosensitive drum 23 so as to be rotatable in the direction of the arrow d ′. A developing roller 26 as a developer regulating member which is disposed with its tip in contact with the developing roller 141 and forms a thin layer of toner 31 with a uniform thickness on the developing roller 141, A first supply for supplying the toner 31 to the developing roller 141 is disposed below the developing roller 141 so as to face the developing roller 141 and to be in contact with the developing roller 141 and to be rotatable in the direction of arrow e ′. A toner supply brush roller 142 as a member and a brush roller (developer supply brush roller); As a second supply member that faces the supply brush roller 142 and is in contact with the toner supply brush roller 142 so as to be rotatable in the direction of the arrow g ′ and supplies the toner 31 to the toner supply brush roller 142. And an auxiliary supply roller 148 as a developer supply member.

  The transfer roller 124, the developing roller 141, and the auxiliary supply roller 148 are rotated in the reverse direction and the toner supply brush roller 142 is rotated in the same direction with respect to the photosensitive drum 23.

  The toner level of the upper surface 31a of the toner 31 accommodated in the casing Cs4 in the initial state where the use of the image forming unit 135Bk is started is set lower than the lower end of the toner supply brush roller 142 as shown in FIG. In this case, the lower end of the brush 142b of the toner supply brush roller 142 refers to the lower end of the brush 142b in a state where no nip is formed between the toner supply brush roller 142 and the auxiliary supply roller 148.

  Each of the developing roller 141, the toner supply brush roller 142, and the auxiliary supply roller 148 is disposed so as to form a nip as shown in FIG.

  The nip amount d6 between the developing roller 141 and the toner supply brush roller 142 and the nip amount d7 between the toner supply brush roller 142 and the auxiliary supply roller 148 are both 0.5 mm.

  Further, the contact facing portion α2 is contacted by the portion where the developing roller 141 and the toner supply brush roller 142 are opposed to each other, and the contact facing portion α2 is contacted by the portion where the toner supply brush roller 142 and the auxiliary supply roller 148 are opposed to each other. The facing portion β2 is formed.

  Next, the toner supply brush roller 142 will be described.

  The toner supply brush roller 142 has a brush 142b formed of a fabric woven with conductive fibers adjusted to a desired resistance value, and is made of conductive metal, in this embodiment, made of stainless steel. It is formed by spirally winding the core metal 142a.

The resistance value of the toner supply brush roller 142 was measured by the high resistance meter 51 (FIG. 5) as in the first embodiment. The resistance value is preferably in the range of 1 × 10 ⁶ [Ω] or more and 1 × 10 ¹⁰ [Ω] or less when a DC voltage of 50 [V] is applied to the toner supply brush roller 142. .

Moreover, the length of the thread | yarn of the brush 142b was 3 [mm], the fineness (thickness) was 6 [denier], and the planting density was 80 [kF / inch < ² >]. Further, as the material of the brush 142b, in the present embodiment, a non-magnetic one-component negatively chargeable toner is used as the toner 31. It is preferable to use nylon (registered trademark), acrylic, or the like located on the charging side, and in this embodiment, nylon fiber (registered trademark) (UUN material manufactured by Unitika Ltd.) was used.

  The auxiliary supply roller 148 is formed by coating a foam layer 148b made of urethane rubber on a metal core 148a made of a conductive metal, in the present embodiment, made of stainless steel. The foam layer 148b had an Asker F hardness of 50 [°].

  Next, the control device of the printer 130 will be described.

  FIG. 26 is a control block diagram of the printer according to the fourth embodiment of the present invention.

  In the figure, reference numeral 70 denotes a print control unit as a first control unit configured by a microprocessor, a ROM, a RAM, an input / output port, a timer, and the like, and prints from a host computer as a host device via an interface control unit 71 Data and control commands are received, the entire sequence of the printer 130 is controlled, and a printing operation is performed. The ROM constitutes a first recording device, the RAM constitutes a second recording device, and a timer constitutes a time measuring element.

  Reference numeral 72 denotes a reception memory as a recording unit for temporarily recording print data input from the host computer via the interface control unit 71. Reference numeral 73 denotes the print data recorded in the reception memory 72 and the print data. An image data editing memory serving as a recording unit for recording image data formed by editing data.

  An operation unit 74 includes an LED as a display element for displaying the status of the printer 130, and switches, keys, and the like as operation elements for an operator to input instructions to the printer 130. Reference numeral 75 denotes a sensor group. The sensor group 75 is a sensor for monitoring the operation state of the printer 130, for example, a paper position detection sensor as a medium detection unit that detects the position of the paper P, and the printer 130. A temperature / humidity sensor as an environment detection unit for detecting a detected environment such as temperature and humidity, a print density sensor as a density detection unit for detecting print density, and a toner 31 in a toner cartridge 32 as a developer storage unit. It comprises a toner remaining amount sensor as a developer remaining amount detecting unit for detecting the remaining amount.

  Reference numeral 76 denotes a charging power source as a first power source. The charging power source applies a predetermined DC voltage to each charging roller 24 according to an instruction from the printing control unit 70 to charge the surface of the photosensitive drum 23. . Reference numeral 77 denotes a developing power source as a second power source. The developing power source 77 applies a predetermined DC voltage to each developing roller 141 to adhere the toner 31 to the electrostatic latent image. Reference numeral 78 denotes a supply power supply as a third power supply. The supply power supply 78 applies a predetermined DC voltage to each toner supply brush roller 142 and supplies the toner 31 to the developing roller 141. Reference numeral 179 denotes an auxiliary supply power supply serving as a fourth power supply. The auxiliary supply power supply 179 applies a predetermined DC voltage to the auxiliary supply roller 148 and replenishes the toner supply brush roller 142 with the toner 31. Reference numeral 80 denotes a transfer power source as a fifth power source. The transfer power source 80 applies a predetermined DC voltage to each transfer roller 124 to transfer a toner image formed on the photosensitive drum 13 to a sheet. Transfer to P.

  The charging power supply 76, the developing power supply 77, the supply power supply 78, the auxiliary supply power supply 179, and the transfer power supply 80 can change the DC voltage applied in accordance with an instruction from the print control unit 70. ing.

  Reference numeral 81 denotes a drive control unit as a second control unit, and the drive control unit 81 drives a drive motor 17 (FIG. 9) as a drive source for rotating the photosensitive drum 23. When the drive motor 17 is driven by the drive controller 81, the photosensitive drum 23 is rotated, and the charging roller 24, the developing roller 141, the toner supply brush roller 142, and the auxiliary supply roller 148 are rotated.

  Reference numeral 82 denotes a head drive control unit as a third control unit. The head drive control unit 82 sends the image data recorded in the image data editing memory 73 to the LED head 11 as an image signal, and the LED head. 11 is driven. Reference numeral 83 denotes a fixing control unit as a fourth control unit. The fixing control unit 83 applies a DC voltage to the fixing unit 13 in order to fix the transferred toner image on the paper P.

  Reference numeral 84 denotes a conveyance control unit as a fifth control unit. The conveyance control unit 84 drives the paper conveyance motor 16 as a conveyance drive unit to convey the paper P, and the print control unit. In response to the instruction 70, a hopping roller 15a (FIG. 2) as a first conveying member and a feeding roller, a registration roller 15b as a second conveying member, a discharge roller 15c as a third conveying member, and the like are rotated. The paper P is transported or stopped at a predetermined timing.

  Next, the operation of the print control unit 70 will be described.

  First, when a print command is received, the print processing unit of the print control unit 70 sends an instruction to the drive control unit 81 to drive the drive motor 17 so that each photosensitive drum 23 is moved at a constant peripheral speed in the direction of arrow a ′. Accordingly, the charging roller 24 is in the direction of arrow c ′, the developing roller 141 is in the direction of arrow d ′, the toner supply brush roller 142 is in the direction of arrow e ′, and the auxiliary supply roller 148 is in the direction of arrow g ′. To be rotated.

  The print processing unit sends an instruction to the charging power source 76, applies a DC voltage to the charging roller 24, uniformly charges the surface of the photosensitive drum 23, and sends an instruction to the head drive control unit 82. Then, the LED head 11 is driven, and light corresponding to the image signal is irradiated to the photosensitive drum 23 to form an electrostatic latent image.

  When the print processing means sends an instruction to the auxiliary supply power source 179 and applies a DC voltage to the auxiliary supply roller 148, the toner 31 in the toner storage chamber 122 is scooped up as the auxiliary supply roller 148 rotates. The auxiliary supply roller 148 and the toner supply brush roller 142 are conveyed to the contact facing portion β2.

  Subsequently, when the print processing means sends an instruction to the supply power supply 78 and applies a DC voltage to the toner supply brush roller 142, the toner conveyed to the contact facing portion β2 as the toner supply brush roller 142 rotates. 31 is supplied to the developing roller 141.

  When the toner 31 adheres to the developing roller 141 in this manner, the toner 31 is conveyed in the direction of the arrow d ′ as the developing roller 141 rotates, and is downstream of the toner supply brush roller 142 in the rotating direction of the developing roller 141. By the developing blade 26 disposed in the toner layer, the toner layer has a uniform thickness. At this time, a DC voltage is applied to the developing blade 26 by a developing blade power source (not shown), and the toner 31 is slid by the developing blade 26 and the developing roller 141 to be frictionally charged.

  Next, the toner 31 that has passed through the developing blade 26 is further conveyed along with the rotation of the developing roller 141, and is sent to the contact portion between the photosensitive drum 23 and the developing roller 141. Since the print processing means sends an instruction to the developing power supply 77 and a DC voltage is applied to the developing roller 141, an electrostatic latent image and a developing are provided between the photosensitive drum 23 and the developing roller 141. A line of electric force is generated by the bias, and the toner 31 adheres to the photosensitive drum 23 by an electrostatic force to form a toner image.

  Then, as the transfer belt 123 travels, the sheet P is sent to each transfer section between the image forming units 135Bk, 135Y, 135M, and 135C and each transfer roller 124, and the print processing means then transfers the transfer power source. An instruction is sent to 80 and a DC voltage is applied to each transfer roller 124. At this time, the toner image on the photoconductive drum 23 is sequentially superimposed and transferred onto the paper P by the transfer bias, and a color toner image is formed.

  Subsequently, the paper P is sent to the fixing device 13, and the color toner image is fixed on the paper P in the fixing device 13 to form a color image. In this way, the paper P on which the color image is formed is discharged out of the apparatus main body.

  On the other hand, the toner 31 slightly remains on each photosensitive drum 23 after the transfer, but the remaining toner 31 is scraped off by the cleaning blade 29. The static eliminator 145 irradiates the surface of the photosensitive drum 23 with static elimination light, removes residual charges due to unexposed charges on the photosensitive drum 23, and resets the charged potential of the photosensitive drum 23. .

  Next, it was evaluated whether or not the image quality was deteriorated when printing was continuously performed using the printer 130 having the above-described configuration.

  The printer 130 having the above-described configuration was subjected to a continuous printing test in which blank paper printing was repeated, and then the supply state and clogging state of the toner 31 were determined.

  In this case, in order to determine the supply state of the toner 31, every time a predetermined number of blank pages are printed in the continuous print test, a predetermined number of sheets, that is, when solid printing of 5 sheets is performed in the present embodiment. It was determined whether or not whitening occurred in the image. If no white spots have occurred, it is determined that a sufficient amount of toner 31 has been supplied to the developing roller 141. If white spots have occurred, a sufficient amount of toner 31 has been supplied to the developing roller 141. Judged not to be supplied.

  Further, in order to determine the clogged state of the toner 31, a continuous printing test was performed, and the weight of the toner 31 carried by the toner supply brush roller 142 when solid printing was performed every time a predetermined blank sheet was printed was calculated. It is determined that the toner 31 is clogged in the gap between the brushes 142b as the weight of the toner 31 carried by the toner supply brush roller 142 increases.

  In the continuous printing test, the charging power source 76 applies a DC voltage of −1000 [V] to the charging roller 24, the developing power source 77 applies a DC voltage of −200 [V] to the developing roller 141, and A DC voltage of −400 [V] is supplied to the developing blade 26 by the power source, a DC voltage of −450 [V] is supplied to the toner supply brush roller 142 by the supply power source 78, and the auxiliary supply roller 148 is supplied by the auxiliary supply power source 179. A DC voltage of −650 [V] was applied to the transfer roller 124 with a DC voltage of −650 [V].

  The image forming unit 20 of the present embodiment is referred to as Example 3, and the image forming unit including the developing roller 141 and the toner supply brush roller 142 as illustrated in FIG. Regarding Example 3, the supply state and clogging state of the toner 31 were determined.

  FIG. 27 is a diagram showing a main part of an image forming unit of Comparative Example 3 in the fourth embodiment of the present invention.

  In the figure, 31 is toner, 31a is the upper surface of the toner 31, 141 is a developing roller, 142 is a toner supply brush roller, and 142b is a brush. In the image forming unit 20 of Comparative Example 3, no auxiliary supply roller is provided, and accordingly, the toner level in the initial state is set so that at least a part of the toner supply brush roller 142 is buried in the toner 31. The

  Next, the determination result of the supply state and the clogging state of the toner 31 when a continuous printing test of 10,000 sheets is performed in the image forming unit 20 of Example 3 and Comparative Example 3 will be described.

  Table 5 shows the determination result of the supply state of the toner 31 at the initial stage in the continuous printing test, after 500 sheets of blank paper, 1000 sheets, 5000 sheets, and 10000 sheets. ○ indicates that no white spots have occurred, and x indicates that white spots have occurred.

Table 6 shows determination results of the clogged state of the toner 31 at the initial stage in the continuous printing test, after 500 sheets of blank paper, 1000 sheets, 5000 sheets, and 10,000 sheets. When the weight of the toner supply brush roller 142 in which the toner 31 enters the gap of the brush 142b is Gb1, and the weight of the toner supply brush roller 142 in which the toner 31 does not enter the gap of the brush 142b is Gb2, the toner supply brush The weight gt of the toner 31 carried by the roller 142 is
gt = Gb1-Gb2
It was. When measuring the weight Gb1 of the toner supply brush roller 142 with the toner 31 attached, excess toner 31 attached to the surface of the toner supply brush roller 142 was removed. When the weight gt is less than 50 [g], the toner 31 is not clogged in the gap of the brush 142b. When the weight gt is 50 [g] or more, the toner 31 is clogged in the gap of the brush 142b. Represent.

  In the image forming unit 20 of Example 3, white spots did not occur even after 10,000 sheets, and the toner 31 did not clog the gap between the brushes 142b.

  On the other hand, in the image forming unit 20 of Comparative Example 3, white spots occurred after 5000 sheets, and the toner 31 was clogged in the gap between the brushes 142b.

  In the image forming unit 20 according to the third exemplary embodiment, the toner level is lower than the lower end of the toner supply brush roller 142, so that the toner supply brush roller 142 is not buried in the toner 31 and the toner 31 is not in the gap of the brush 142 b. It is possible to suppress clogging.

  Further, whenever the toner supply brush roller 142 of Comparative Example 3 is rotated, the toner supply brush roller 142 is buried in the toner 31 in an area AR1 surrounded by a broken line shown in FIG. Therefore, the amount of toner 31 entering the gap between the brushes 142b of the toner supply brush roller 142 gradually increases, and the toner 31 is clogged in the gaps between the brushes 142b.

  Thus, in the present embodiment, the toner supply brush roller 142 is disposed in contact with the auxiliary supply roller 148 at the lower side, and the toner level is made lower than the lower end of the brush 142b of the toner supply brush roller 142. 142 b is not buried in the toner 31. Therefore, since the toner 31 can be prevented from entering and clogging in the gap of the brush 142b, the elasticity of the brush 142b is not lowered and the toner 31 can be stably supplied to the developing roller 141.

  As a result, it is possible to prevent the image quality from deteriorating.

  Next, a fifth embodiment of the present invention will be described. In addition, about the thing which has the same structure as 1st-4th embodiment, the same code | symbol is provided and the effect of the embodiment is used about the effect of the invention by having the same structure.

  FIG. 28 is a conceptual diagram of a printer according to the fifth embodiment of the present invention.

  As shown in the figure, a printer 130 as an image forming apparatus includes image forming units 155Bk, 155Y, 155M, and 155C for each toner as developer of four colors of black, yellow, magenta, and cyan. The units 155Bk, 155Y, 155M, and 155C include a photoconductive drum 23 as an image carrier. Then, an LED head 11 as an exposure device is disposed so as to face each photoconductor drum 23, and an electrostatic latent image as a latent image is formed on the photoconductor drum 23 by the LED head 11, and a developer carrying member. The electrostatic latent image is developed by a developing roller (not shown) as a toner image as a developer image of each color.

  A transfer unit u1 is disposed along the image forming units 155Bk, 155Y, 155M, and 155C. The transfer unit u 1 includes a driving roller r 11, a driven roller r 12, a transfer belt 123 that is stretched between the driving roller r 11 and the driven roller r 12, and runs in the direction of the arrow, and each photoconductor via the transfer belt 123. A transfer roller 124 as a transfer member brought into contact with the drum 23 is provided.

  Next, the image forming units 155Bk, 155Y, 155M, and 155C will be described. Since the image forming units 155Bk, 155Y, 155M, and 155C have the same structure, only the image forming unit 155Bk will be described.

  FIG. 29 is a schematic view of an image forming unit according to the fifth embodiment of the present invention.

  In the figure, 155Bk is an image forming unit, and the image forming unit 155Bk is detachably disposed on the main body of the image forming unit 155Bk, that is, the image forming unit main body 155a and the image forming unit main body 155a. In addition, a toner cartridge 32 as a developer accommodating portion is provided, and a toner accommodating chamber as a developer accommodating chamber for accommodating toner 31 as a developer is formed in the toner cartridge 32. A casing Cs5 as a casing of the image forming unit main body 155a includes a receiving portion Csa for receiving the toner cartridge 32.

  Then, in order to supply the toner 31 into the image forming unit main body 155a, a toner discharge port (not shown) as a developer discharge port at the bottom of the toner cartridge 32 corresponds to the developer discharge port in the receiving unit Csa. A toner receiving port h2 is formed as a developer receiving port, and the toner receiving port h2 is opened and closed by a shutter 32a as an opening / closing member.

  The image forming unit main body 155a has a first chamber rm1 as a developer holding space and a second chamber as a developer supply space by a partition wall w1 formed by hanging from a predetermined portion of the receiving portion Csa. The photosensitive drum 23, a charging roller 24 as a charging device, a developing device 90, a cleaning blade 29 as a cleaning member, a static elimination device 145, and the like are disposed in the first chamber rm1.

  The developing device 90 includes a developing roller 141, a toner supply brush roller 142 as a first supply member and a brush roller (developer supply brush roller), a development blade 26 as a developer regulating member, a second supply member. An auxiliary supply roller 148 as a supply member and as a developer replenishment member, is rotatably arranged in the directions of arrows k1 and k2, and detects a toner level representing the remaining amount of toner 31 in the casing Cs5. First and second detection levers 34H and 34L are provided.

  The rotation center of the first detection lever 34H is located at the lower end position of the brush 142b of the toner supply brush roller 142, and the rotation center of the second detection lever 34H is located at the lower end position of the auxiliary supply roller 148. The first and second detection levers 34H and 34L are formed of a crank-shaped metal bar and rotated along the broken line shown in the drawing, as in the first embodiment. The first and second detection levers 34H and 34L are attached with first and second reflectors (not shown) as detection elements similar to those in the first embodiment.

  The apparatus main body is provided with first and second light detectors facing the first and second reflectors, and the first light detector emits laser light. First and second light-emitting elements as bodies, and first and second light-receiving elements as second detectors that receive the laser light reflected by the first and second reflectors. The first and second light receiving elements generate level signals as sensor outputs, respectively, and the first and second light receiving elements serve as first and second level signal generating elements. A level sensor is configured.

  In the present embodiment, when the first and second light reflectors are positioned at the intermediate point pM between the apex pU (FIG. 9) and the bottom point pL, The first and second light receiving elements are set to receive the laser light emitted by the first and second light receiving elements.

  Then, as shown in FIG. 12, when the toner level is higher than the intermediate point pM of the rotation trajectories of the first and second detection levers, the light reception time T of the laser light by the first and second light receiving elements is the first. When the value T1 is lower than the intermediate point pM of the rotation trajectories of the first and second detection levers, the light reception time T of the laser light by the first and second light receiving elements is the second threshold value. When the value T2 is reached and the toner level is equal to the intermediate point pM of the rotation trajectories of the first and second detection levers, the light receiving time T becomes the value T3.

  Next, the control device of the printer 130 will be described.

  FIG. 30 is a control block diagram of the printer according to the fifth embodiment of the present invention.

  In the figure, 32a is a shutter, 85 is a shutter drive control unit as a sixth control unit, 70 is a print control unit as a first control unit, 63H and 63L are first and second light emitting elements, and 64H and 64L. Are the first and second light receiving elements, 86H is a first timer as a first time measuring member for measuring the light receiving time T of the laser light by the first light receiving element 64H, and 86L is a laser by the second light receiving element 64L. It is the 2nd timer as a 2nd time measuring member which measures light reception time T.

  The charging power supply 76 as the first power supply applies a DC voltage of −1000 [V] to the charging roller 24, and the developing power supply 77 as the second power supply supplies −200 [V] to the developing roller 141. A DC voltage of -400 [V] is applied to the developing blade 26 by a power supply for the developing blade, and a DC voltage of -450 [V] is applied to the toner supply brush roller 142 by a supply power supply 78 as a third power supply. However, the auxiliary power supply 179 as the fourth power supply causes a DC voltage of −650 [V] to the auxiliary supply roller 148, and the transfer power supply 80 as the fifth power supply supplies +3000 [V] to the transfer roller 124. DC voltage is applied.

  Next, the operation of the print control unit 70 will be described.

  FIG. 31 is a flowchart showing the operation of the print control unit in the fifth embodiment of the present invention.

  In this case, the shutter 32 a is opened and closed so that the toner level is between the lower end of the brush 142 b of the toner supply brush roller 142 and the lower end of the auxiliary supply roller 148.

  Therefore, the toner level detection processing unit as the developer level detection processing unit of the print control unit 70 reads the light reception times T measured by the first and second timers 86H and 86L, and sets them as TH and TL, respectively. .

  Next, the toner level determination processing unit as the developer level determination processing unit of the print control unit 70 determines whether the toner level is lower than the lower end of the auxiliary supply roller 148 depending on whether the light reception time TL is the value T2. to decide.

  When the light reception time TL is the value T2 and the toner level is lower than the lower end of the auxiliary supply roller 148, the toner supply processing unit as the developer supply processing unit of the print control unit 70 sends an instruction to the shutter drive control unit 85. Then, the shutter 32a is opened. In this way, the toner 31 in the toner cartridge 32 is supplied into the second chamber rm2.

  When the light reception time TL is not the value T2 and the toner level is equal to or higher than the lower end of the auxiliary supply roller 148, the print processing unit continues the printing operation. In this case, the shutter 32a is left open.

  Subsequently, the toner level determination processing unit determines whether the toner level is equal to or higher than the brush 142b of the toner supply brush roller 142 based on whether the light reception time TH is the value T1.

  When the light receiving time TH is the value T1 and the toner level is equal to or higher than the brush 142b of the toner supply brush roller 142, the toner supply processing unit sends an instruction to the shutter drive control unit 85 and closes the shutter 32a. In this way, the toner 31 in the toner cartridge 32 is not supplied into the second chamber rm2.

  If the light receiving time TH is not the value T1 and the toner level is lower than the brush 142b of the toner supply brush roller 142, the print processing means continues the printing operation. In this case, the shutter 32a is left open.

Next, a flowchart will be described.
Step S11 The printing operation is started.
Step S12 Wait until the light reception time TL reaches the value T2, and if the light reception time TL reaches the value T2, the process proceeds to step S13.
Step S13: The shutter 32a is opened.
Step S14 Wait until the light receiving time TH reaches the value T1, and if the light receiving time TH reaches the value T1, the process proceeds to step S15.
Step S15: The shutter 32a is closed and the process returns to Step S11.

  As described above, in this embodiment, the auxiliary supply roller 148 is disposed below the toner supply brush roller 142, and the toner levels are the lower end of the brush 142b of the toner supply brush roller 142 and the lower end of the auxiliary supply roller 148. Since the shutter 32 a is opened and closed so as to be in between, the toner supply brush roller 142 can be lifted from the toner 31.

  Therefore, the brush 142b is not buried in the toner 31, and the toner 31 can be prevented from entering and clogging into the gap of the brush 142b. Therefore, the elasticity of the brush 142b is not lowered, and the toner 31 is stabilized on the developing roller 21. Can be supplied.

  In the first to third embodiments, the printer 10 including one image forming unit 20 is described. However, the present invention can be applied to a color printer including a plurality of image forming units. In the fourth and fifth embodiments, the color printer 130 is described. However, the present invention can be applied to a monochrome printer.

  In the first to third embodiments, the toner collection brush roller 25 is disposed to collect the toner 31 on the developing roller 21. The toner 31 can be collected by bringing the metal roller, rubber roller, sponge-like rubber roller, conductive film or the like into contact with the developing roller 21.

  Furthermore, in each embodiment, a printer has been described. However, the present invention can be applied to a copying machine, a facsimile machine, a multifunction machine, and the like.

  The present invention is not limited to the above embodiments, and various modifications can be made based on the gist of the present invention, and they are not excluded from the scope of the present invention.

20, 135Bk, 135Y, 135M, 135C, 155Bk, 155Y, 155M, 155C Image forming unit 21, 141 Developing roller 22, 142 Toner supply brush roller 30, 148 Auxiliary supply roller 31 Toner 31a Upper surface Cs2 to Cs5 Casing rm Developer holding Space rm1 first chamber β1, β2 contact facing part

Claims (17)

(A) a developer carrying member carrying the developer;
(B) a first supply member that is rotatably disposed to face the developer carrying member and supplies the developer to the developer carrying member;
(C) a second supply member which is rotatably disposed in contact with the first supply member and supplies developer to the first supply member;
(D) a housing that houses the developer carrier and the first and second supply members and forms a developer holding space for holding the developer ;
(E) an openable / closable member arranged to be openable and closable for supplying the developer in the developer accommodating chamber to the developer holding space;
(F) developer level determination processing means for determining the level of the upper surface of the developer in the developer holding space;
(G) having developer supply processing means for opening and closing the opening and closing member according to the level of the upper surface of the developer in the developer holding space ;
(H) The image forming unit characterized in that the level of the upper surface of the developer held in the developer holding space is set lower than the contact facing portion of the first and second supply members.   The image forming unit according to claim 1, wherein the second supply member is disposed below the first supply member.   The image forming unit according to claim 1, wherein the developer carrying member and the first supply member are rotated in the same direction. The image forming unit according to claim 1, wherein the first supply member is a brush roller including a cored bar and a brush . Before Symbol developer supply processing means, wherein the level of the upper surface of the developer first image forming unit according to claim 1, lower than the contact facing portion of the second supply member. The image forming unit according to claim 1 , wherein the developer supply processing unit places a level of an upper surface of the developer between a lower end of the first supply member and a lower end of the second supply member. The image according to any one of claims 1 to 6 , further comprising a developer collecting member that is rotatably arranged in contact with the developer carrying member and collects the developer remaining on the developer carrying member. Forming unit.   The image forming unit according to claim 4, further comprising a developer flying member that is disposed in contact with the brush roller and causes the developer attached to the brush roller to fly. The image forming unit according to claim 8 , wherein the developer flying member is rotated in a direction opposite to the brush roller. (A) a developer carrying member carrying the developer;
(B) a first supply member that is rotatably disposed to face the developer carrying member and supplies the developer to the developer carrying member;
(C) a second supply member which is rotatably disposed in contact with the first supply member and supplies developer to the first supply member;
(D) a housing that houses the developer carrier and the first and second supply members and forms a developer holding space for holding the developer;
(E) The level of the upper surface of the developer held in the developer holding space is set lower than the contact facing portion of the first and second supply members,
(F) The first supply member is a brush roller provided with a cored bar and a brush,
(G) An image forming unit, wherein the developer flying member is disposed in contact with the brush roller, and is rotated in a direction opposite to the brush roller to cause the developer attached to the brush roller to fly. The image forming unit according to claim 10, wherein the second supply member is disposed below the first supply member. The image forming unit according to claim 10, wherein the developer carrying member and the first supply member are rotated in the same direction. (A) an openable / closable member arranged to be openable and closable for supplying the developer in the developer accommodating chamber to the developer holding space;
(B) developer level determination processing means for determining the level of the upper surface of the developer in the developer holding space;
The image forming unit according to claim 10, further comprising: a developer supply processing unit that opens and closes the opening and closing member according to a level of the upper surface of the developer in the developer holding space. The image forming unit according to claim 13, wherein the developer supply processing unit lowers the level of the upper surface of the developer from a contact facing portion of the first and second supply members. The image forming unit according to claim 13, wherein the developer supply processing unit places a level of an upper surface of the developer between a lower end of the first supply member and a lower end of the second supply member. The image according to any one of claims 10 to 15, further comprising a developer collecting member that is rotatably disposed in contact with the developer carrying member and collects the developer remaining on the developer carrying member. Forming unit. An image forming apparatus comprising the image forming unit 20 according to claim 1 .

Images