JP2021152629A - Developing device and image forming apparatus including the same - Google Patents

Abstract

To provide a developing device of a non-magnetic one-component system that can stably prevent toner from being fastened to a surface of a regulation blade for a long period without limiting the particle diameter of the toner, and an image forming apparatus including the same.SOLUTION: A developing device comprises: a developing roller that is opposite to a photoreceptor drum; and a metal regulation blade 334. The regulation blade 334 is in contact with a peripheral surface of the developing roller to regulate the amount of toner layered on the developing roller. A free end part of the regulation blade 334 includes a contact part CP that is in contact with the peripheral surface of the developing roller, a leading end side non-contact part RP1 that is arranged closer to the leading end than the contact part CP and arranged at an interval from the peripheral surface, and vibration promotion parts 334Q that are arranged in the leading end side non-contact part RP1 and receive the flow of toner conveyed by the developing roller to promote vibration of the free end part.SELECTED DRAWING: Figure 6

Description

The present invention relates to a developing apparatus for developing an electrostatic latent image formed on a photoconductor drum using a non-magnetic one-component developer, and an image forming apparatus provided with this developing apparatus.

Conventionally, it has been used in an image forming apparatus such as a printer, and as a developing apparatus for developing an electrostatic latent image formed on a photoconductor drum using a non-magnetic one-component developer, on a developing roller and the surface of the developing roller. There are known those having a regulating blade (elastic blade) that abuts and regulates the amount of toner layer and charges the toner. In such a developing device, when the non-magnetic one-component toner melted by receiving frictional force from the regulating blade adheres to the regulating blade and grows to a size of several tens of μm to several hundreds of μm, the toner layer on the developing roller moves. There was a problem that it was hindered and white streaks were generated on the image.

Therefore, Patent Document 1 discloses that the proportion of fine particles of 5 μm or less in the toner contained in the developing apparatus is limited to 10% by number or less. Since the fine particle toner is more likely to adhere to the regulation blade than the large toner, limiting the proportion of the fine particles reduces the adhesion of the toner to the regulation blade.

Japanese Unexamined Patent Publication No. 2001-350285

It is desirable to use toner with a small particle size in order to improve the image quality of the image forming apparatus. In the technique described in Patent Document 1, since the proportion of toner having a small particle size is limited, the adhesion of toner to the regulation blade is reduced, but there is a problem that improvement of image quality is hindered.

The present invention has been made to solve the above problems, and it is intended to stably prevent the toner from sticking to the surface of the regulating blade for a long period of time without limiting the particle size of the toner. It is an object of the present invention to provide a non-magnetic one-component developing apparatus capable of the above and an image forming apparatus equipped with the developing apparatus.

The developing apparatus according to one aspect of the present invention comprises a developing housing for accommodating a non-magnetic one-component toner and an elastic body having a cylindrical shape, is rotatably supported by the developing housing, and develops on a predetermined photoconductor drum. A developing roller arranged to face each other in the nip portion and carrying the toner on the peripheral surface and a facing surface facing the developing roller are included, and the facing surface abuts on the peripheral surface of the developing roller and is placed on the developing roller. A metal regulating blade that regulates the layer amount of the toner is provided, and the regulating blade is provided with a fixed end portion fixed to the developing housing and a fixed end portion on a side opposite to the fixed end portion. Is also a free end portion arranged on the upstream side in the rotational direction of the developing roller, which is arranged on the facing surface and is pressed against the peripheral surface of the developing roller while being pressed against the peripheral surface of the developing roller along the axial direction of the developing roller. A free end portion including a contact portion in contact with the front end side, a non-contact portion on the tip end side of the facing surface which is arranged on the tip end side of the contact portion and arranged at a distance from the peripheral surface, and the above. It has a vibration promoting portion which is arranged in the tip side non-contact portion and promotes vibration of the tip side non-contact portion by the moving force of the toner conveyed by the developing roller.

According to this configuration, the vibration promoting portion provided on the tip-side non-contact portion of the free end portion promotes the vibration of the tip-side non-contact portion by the moving force of the toner conveyed by the developing roller. Therefore, when the toner starts to adhere to the contact portion or the tip side non-contact portion of the regulation blade, the toner is easily peeled off due to the vibration of the tip side non-contact portion, and the growth of the toner adhesion is suppressed. As a result, it becomes possible to allow the toner to smoothly enter toward the contact portion and to charge the toner while controlling the amount of the toner layer at the contact portion, and thin-layer streaks on the developing roller and white streaks on the image are generated. Can be prevented. Further, since the vibration promoting portion is provided in the non-contact portion on the tip side and does not directly vibrate the contact portion, it is suppressed that the vibration has a great influence on the toner layer amount regulation and charging in the contact portion. ..

In the above configuration, it is desirable that the vibration promoting portion is a plurality of cut portions formed in the tip-side non-contact portion at intervals in the axial direction.

According to this configuration, since a plurality of notches are formed in the tip-side non-contact portion, the tip-side non-contact portion can be easily vibrated.

In the above configuration, it is desirable that the vibration promoting portion is a plurality of notches formed in the tip-side non-contact portion at intervals in the axial direction.

According to this configuration, a plurality of notches are formed in the non-contact portion on the tip side, so that a part of the toner that has entered between the non-contact portion on the tip side and the developing roller as the developing roller rotates. , A flow is formed outward in the radial direction of the developing roller. As a result, a difference in the force acting on the tip-side non-contact portion is generated between the portion with the notch and the portion without the notch, and the tip-side non-contact portion can be reliably vibrated.

In the above configuration, it is desirable that the vibration promoting portion is a plurality of holes formed in the tip-side non-contact portion at intervals in the axial direction.

According to this configuration, a plurality of holes are formed in the non-contact portion on the tip side, so that a part of the toner that has entered between the non-contact portion on the tip side and the developing roller as the developing roller rotates can be used. A flow is formed outward in the radial direction of the developing roller. As a result, a difference in the force acting on the tip-side non-contact portion is generated between the portion with the hole and the portion without the hole, and the tip-side non-contact portion can be reliably vibrated. Further, when a plurality of holes are formed in the tip-side non-contact portion, the shape of the outer peripheral portion of the tip-side non-contact portion can be maintained, so that the rigidity of the tip-side non-contact portion may decrease. Be prevented.

In the above configuration, it is desirable that the surface roughness Ra of the contact portion is set in the range of 0.02 or more and 0.1 or less. Further, it is more desirable that the surface roughness Ra of the contact portion is set in the range of 0.04 or more and 0.08 or less.

According to this configuration, the wax component and the external additive component are less likely to adhere to the fine uneven portion of the contact portion, and the toner sticking at the contact portion is further suppressed.

In the above configuration, the free end portion is arranged so as to extend outward in the radial direction of the developing roller from the tip end portion of the facing surface, and a part of the toner conveyed by the developing roller is provided in the radial direction. It is desirable to further include a guide portion that guides to the outside.

According to this configuration, the excess toner that has been conveyed on the developing roller and reached the regulating blade is guided outward in the radial direction by the guide portion, so that excess toner enters between the regulating blade and the developing roller. Is prevented. As a result, it is possible to further prevent the toner from sticking to the contact portion. Further, the vibration of the non-contact portion on the tip side can be further promoted by the impact when the toner collides with the guide portion as the developing roller rotates.

In the above configuration, the melt viscosity (Pa · s) of the toner at 95 ° C. may be set in the range of 10,000 or more and 20,000 or less.

According to this configuration, even when so-called low-temperature fixing toner is used, it is possible to prevent the toner from sticking to the regulation blade. That is, even if the toner has a relatively low melt viscosity and the viscosity tends to increase depending on the temperature inside the apparatus, it is possible to prevent the toner from sticking to the regulation blade.

The image forming apparatus according to another aspect of the present invention includes the developing apparatus described above and a photoconductor drum on which an electrostatic latent image is formed on the surface and the toner is supplied from the developing roller.

According to this configuration, it is possible to provide an image forming apparatus that suppresses image defects caused by sticking of toner to a regulating blade by using non-magnetic toner.

According to the present invention, a non-magnetic one-component developing apparatus capable of stably suppressing the adhesion of toner to the surface of a regulating blade for a long period of time without limiting the particle size of the toner, and a developing apparatus thereof. An image forming apparatus provided is provided.

It is sectional drawing which shows the internal structure of the image forming apparatus which concerns on one Embodiment of this invention. It is sectional drawing around the photoconductor drum of the image forming apparatus which concerns on one Embodiment of this invention. It is a figure which showed the positional relationship in the axial direction of the developing roller, the regulation blade, and a sheet of the developing apparatus which concerns on one Embodiment of this invention. It is a figure for exemplifying the parameter of the regulation blade of the developing apparatus which concerns on one Embodiment of this invention. It is a figure for demonstrating the movement of toner around the regulation blade of the developing apparatus which concerns on one Embodiment of this invention. It is an enlarged view of the regulation blade of the developing apparatus which concerns on one Embodiment of this invention. It is an enlarged exploded perspective view of the regulation blade of the developing apparatus which concerns on one Embodiment of this invention. It is an enlarged view of the end part of the regulation blade of the developing apparatus which concerns on 1st modification embodiment of this invention. It is an enlarged exploded perspective view of the end portion of the regulation blade of the developing apparatus which concerns on 1st modification embodiment of this invention. It is an enlarged view of the regulation blade of the developing apparatus which concerns on the 2nd modification embodiment of this invention. It is an enlarged exploded perspective view of the regulation blade of the developing apparatus which concerns on the 2nd modification embodiment of this invention.

<About the image forming device>
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a side sectional view showing an internal structure of an image forming apparatus 1 according to an embodiment of the present invention. Here, a monochrome printer is illustrated as the image forming apparatus 1, but the image forming apparatus may be a copying machine, a facsimile apparatus, or a multifunction device having these functions, and an image forming apparatus for forming a color image. It may be.

The image forming apparatus 1 includes a main body housing 10 having a housing structure having a substantially rectangular parallelepiped shape, a paper feeding unit 20, an image forming unit 30, and a fixing unit 40 housed in the main body housing 10.

A front cover 11 is provided on the front surface side of the main body housing 10, and a rear cover 12 is provided on the rear surface side. The rear cover 12 is a cover that is opened during seat jam or maintenance. Further, the upper surface of the main body housing 10 is provided with a paper ejection portion 13 from which the sheet P after image formation is discharged. Various devices for performing image formation are installed in the internal space S defined by the front cover 11, the rear cover 12, and the paper ejection unit 13.

The paper feed unit 20 includes a paper feed cassette 21 that houses the sheet P to be subjected to the image forming process. A part of the paper cassette 21 projects further forward from the front surface of the main body housing 10. The upper surface of the portion of the paper cassette 21 housed in the main body housing 10 is covered with the paper cassette top plate 21U. The paper cassette 21 is provided with a sheet storage space for accommodating the bundle of sheets P, a lift plate for lifting up the bundle of sheets P for paper feeding, and the like. A sheet feeding portion 21A is provided on the upper portion of the paper feed cassette 21 on the rear end side. In the sheet feeding section 21A, a paper feeding roller 21B for feeding out the uppermost sheet P of the sheet bundle in the paper feed cassette 21 one by one is arranged.

The image forming unit 30 performs an image forming process of forming a toner image on the sheet P sent out from the paper feeding unit 20. The image forming unit 30 includes a photoconductor drum 31, a charging device 32, an exposure device (not shown in FIG. 2), a developing device 33, and a transfer roller 34 arranged around the photoconductor drum 31. include.

The photoconductor drum 31 includes a rotation axis and a cylindrical surface that rotates around the rotation axis. An electrostatic latent image is formed on the cylindrical surface, and a toner image corresponding to the electrostatic latent image is supported on the cylindrical surface. As the photoconductor drum 31, an OPC photoconductor drum can be used.

The charging device 32 uniformly charges the surface of the photoconductor drum 31, is arranged at a predetermined interval with respect to the photoconductor drum 31, and discharges when a predetermined voltage is applied. Includes Scorotron.

The exposure device has a laser light source and optical devices such as a mirror and a lens, and irradiates the peripheral surface of the photoconductor drum 31 with light modulated based on image data given from an external device such as a personal computer. To form an electrostatic latent image.

The developing device 33 supplies toner to the peripheral surface of the photoconductor drum 31 in order to develop the electrostatic latent image on the photoconductor drum 31 to form a toner image.

The transfer roller 34 is a roller for transferring the toner image formed on the peripheral surface of the photoconductor drum 31 onto the sheet P. The transfer roller 34 is in contact with the cylindrical surface of the photoconductor drum 31 to form a transfer nip portion. A transfer bias having a polarity opposite to that of the toner is applied to the transfer roller 34.

The fixing unit 40 performs a fixing process for fixing the transferred toner image on the sheet P. The fixing portion 40 includes a fixing roller 41 having a heating source inside, and a pressure roller 42 that is pressed against the fixing roller 41 to form a fixing nip portion between the fixing roller 41. When the sheet P on which the toner image is transferred is passed through the fixing nip portion, the toner image is fixed on the sheet P by heating by the fixing roller 41 and pressing by the pressure roller 42. In this embodiment, the melt viscosity (Pa · s) of the non-magnetic one-component toner used in the developing apparatus 33 at 95 ° C. is set in the range of 10,000 or more and 20,000 or less.

The main body housing 10 is provided with a main transport path 22F and a reverse transport path 22B for transporting the seat P. The main transport path 22F is provided as a paper ejection port facing the paper ejection portion 13 on the upper surface of the main body housing 10 from the sheet feeding portion 21A of the paper feeding unit 20 via the image forming portion 30 and the fixing portion 40. It extends to 14. The reverse transfer path 22B is a transfer path for returning the single-sided printed sheet P to the upstream side of the image forming unit 30 in the main transfer path 22F when double-sided printing is performed on the sheet P.

The main transport path 22F extends so as to pass through the transfer nip portion formed by the photoconductor drum 31 and the transfer roller 34 from the lower side to the upper side. Further, a resist roller pair 23 is arranged on the upstream side of the main transport path 22F with respect to the transfer nip portion. The sheet P is temporarily stopped by the resist roller pair 23, skew correction is performed, and then the sheet P is sent out to the transfer nip portion at a predetermined timing for image transfer. A plurality of transport rollers for transporting the sheet P are arranged at appropriate positions on the main transport path 22F and the reverse transport path 22B. For example, a paper discharge roller pair 24 is arranged in the vicinity of the paper discharge port 14.

The reversing transport path 22B is formed between the outer surface of the reversing unit 25 and the inner surface of the rear cover 12 of the main body housing 10. One roller of the transfer roller 34 and the resist roller pair 23 is mounted on the inner surface of the reversing unit 25. The rear cover 12 and the reversing unit 25 can each rotate around the axis of the fulcrum portion 121 provided at the lower end thereof. When a seat jam occurs in the reverse transport path 22B, the rear cover 12 is opened. When a sheet jam occurs in the main transport path 22F, or when the unit of the photoconductor drum 31 or the developing device 33 is taken out to the outside, the reversing unit 25 is opened in addition to the rear cover 12.

<About developing equipment>
FIG. 2 is a cross-sectional view showing the structure around the photoconductor drum 31. In the present embodiment, the transfer roller 34 is arranged behind the photoconductor drum 31 so as to come into contact with the photoconductor drum 31, and the charging device 32 is arranged in front of and above the photoconductor drum 31 at predetermined intervals. It is arranged so as to face 31. A transfer nip portion is formed between the photoconductor drum 31 and the transfer roller 34, and the sheet P passes through the transfer nip portion as shown by an arrow in FIG. At this time, the toner image is transferred from the photoconductor drum 31 to the sheet P.

The developing device 33 is arranged in front of and below the photoconductor drum 31 so as to face the photoconductor drum 31. The developing apparatus 33 includes a developing housing 330, a developing roller 331, a supply roller 332, a stirring paddle 333, a regulation blade 334, a blade holding portion 335, and a lower seal 336 (seal member).

The developing housing 330 houses a non-magnetic one-component toner inside. The developing housing 330 has a housing body 330A and a housing lid 330B. As shown in FIG. 2, an opening for exposing a part of the developing roller 331 to the photoconductor drum 31 side is formed at the rear end portion of the developing housing 330.

The developing roller 331 is rotatably supported by the developing housing 330 and has a peripheral surface for carrying toner. The developing roller 331 comes into contact with the photoconductor drum 31 and forms a developing nip portion for supplying toner to the photoconductor drum 31 together with the photoconductor drum 31. That is, the developing roller 331 is arranged in the developing nip portion so as to face the photoconductor drum 31. In the developing roller 331, a cylindrical rubber layer (elastic body) is formed around the shaft of the SUS material or the SUM material. The rubber layer is made of conductive urethane foam rubber as an example. Further, a coat layer made of silicon is formed on the surface of the rubber layer.

The supply roller 332 is arranged in front of and below the developing roller 331 so as to face the developing roller 331, and is rotatably supported by the developing housing 330. The supply roller 332 comes into contact with the developing roller 331 and forms a supply nip portion for supplying toner to the developing roller 331. The supply roller 332 is formed by fixing a cylindrical conductive urethane foam rubber around a predetermined shaft. Further, the supply nip width is set in a range of 0.2 mm or more and 1.5 mm or less in the rotational direction when viewed along the radial direction.

The stirring paddle 333 is rotatably supported by the developing housing 330 in front of the supply roller 332. As shown in FIG. 2, the stirring paddle 333 includes an L-shaped shaft in a cross-sectional view and a PET film arranged so as to extend radially from the shaft.

Note that FIG. 2 shows the rotation directions of the developing roller 331, the supply roller 332, and the stirring paddle 333 when the image forming operation on the sheet P is performed in the image forming apparatus 1. The developing roller 331 rotates so that its surface moves in the same direction as the surface of the photoconductor drum 31 at the developing nip portion. As an example, the peripheral speed ratio of the developing roller 331 to the photoconductor drum 31 is set to 1.55 times. The supply roller 332 rotates so that its surface moves in the direction opposite to the surface of the developing roller 331. The peripheral speed ratio of the developing roller 331 to the supply roller 332 is set to 1.55 times. The stirring paddle 333 rotates so as to supply the toner in the developing housing 330 to the supply roller 332 while scooping up the toner. Further, the stirring paddle 333 rotates in the same direction as each other in the region opposite to the supply roller 332.

The regulation blade 334 is made of a thin metal plate, and the surface (periphery) of the developing roller 331 is located downstream of the supply nip portion in the rotational direction of the developing roller 331 and upstream of the developing nip portion in the rotational direction of the developing roller 331. It is in contact with the surface). The regulation blade 334 is fixed to the developing housing 330 so as to be inclined toward the upstream side in the rotational direction of the developing roller 331. The regulation blade 334 regulates the layer amount (layer thickness) of the toner on the developing roller 331.

The blade holding portion 335 holds the regulation blade 334 and is fixed to the housing lid portion 330B of the developing housing 330.

The lower seal 336 is supported by the housing body 330A so as to close the gap between the developing roller 331 and the housing body 330A on the side opposite to the regulation blade 334. The tip of the lower seal 336 is in contact with the surface of the developing roller 331.

In the present embodiment, as shown in FIG. 2, the charging device 32 is arranged on the downstream side in the rotation direction of the photoconductor drum 31 when viewed from the transfer nip portion formed by the photoconductor drum 31 and the transfer roller 34. Therefore, a so-called cleanerless method is adopted, in which a known cleaning device is not provided. That is, when the toner image is transferred from the photoconductor drum 31 to the sheet P at the transfer nip portion, the untransferred toner remains on the photoconductor drum 31. The untransferred toner passes through the charging device 32 and is recovered from the photoconductor drum 31 by the developing roller 331 of the developing device 33. At this time, when an image (toner image) is continuously formed on the sheet P, the developing roller 331 collects the untransferred toner from the photoconductor drum 31, while the electrostatic latent on the photoconductor drum 31. Supply toner to the image.

On the other hand, the supply roller 332 supplies new toner to the developing roller 331 at the supply nip portion, and collects the toner that has not been supplied from the developing roller 331 to the photoconductor drum 31 from the developing roller 331.

FIG. 3 is a diagram showing the positional relationship between the developing roller 331 of the developing apparatus 33 according to the present embodiment, the regulating blade 334, and the sheet P in the axial direction. In addition, in FIG. 3, another regulation blade 334Z compared with the regulation blade 334 according to the present embodiment is also shown as a comparative example. FIG. 4 is a diagram for exemplifying the parameters of the regulation blade 334 of the developing device 33 according to the present embodiment. FIG. 5 is a diagram for explaining the movement of toner around the regulation blade 334 of the developing apparatus 33 according to the present embodiment.

With reference to FIG. 3, in the present embodiment, the toner supporting region of the developing roller 331 is formed corresponding to the A4 size (210 inches) as the size of the sheet P. Toner non-supporting regions that do not support toner are arranged at both ends of the toner-supporting region of the developing roller 331. Further, the developing housing 330 is provided with a pair of left and right felt seals 337 along the peripheral surface of the developing roller 331. Both ends of the regulation blade 334 are arranged so as to be sandwiched between the developing roller 331 and the felt seal 337. As a result, the toner in the developing housing 330 is prevented from leaking to the outside in the axial direction of the developing roller 331. In FIG. 3, the rotation shaft 331A of the developing roller 331 is shown. The two pairs of holes formed at both ends of the blade holding portion 335 are positioning holes for the developing housing 330 and screw holes for fastening the blade holding portion 335 to the developing housing 330. On the other hand, a pair of positioning holes for yag welding to the blade holding portion 335 are formed at both ends of the regulation blade 334.

With reference to FIG. 4, the regulation blade 334 includes a facing surface 334L facing the developing roller 331. Further, the regulation blade 334 has a fixed end portion 334J and a free end portion 334K.

The fixed end portion 334J is fixed to the developing housing 330 via the blade holding portion 335 described above.

The free end portion 334K is arranged on the side opposite to the fixed end portion 334J and on the upstream side in the rotational direction of the developing roller 331 with respect to the fixed end portion 334J.

Further, referring to FIG. 5, the free end portion 334K of the regulation blade 334 has a contact portion CP, a tip end side non-contact portion RP1 and a proximal end side non-contact portion RP2.

The contact portion CP is arranged near the tip end portion of the facing surface 334L, and when the toner is not supported on the developing roller 331, the regulation blade 334 is pressed against the peripheral surface of the developing roller 331. The contact portion CP comes into contact with the peripheral surface of the developing roller 331 along the axial direction of the developing roller 331.

The tip-side non-contact portion RP1 is arranged on the tip side of the facing surface 334L with respect to the contact portion CP, and is arranged at intervals with respect to the peripheral surface of the developing roller 331. Further, the base end side non-contact portion RP2 is arranged on the fixed end portion 334J side of the facing surface 334L with respect to the contact portion CP, and is arranged at intervals with respect to the peripheral surface of the developing roller 331. These non-contact portions do not come into contact with the peripheral surface of the developing roller 331, but can come into contact with the toner supported on the developing roller 331.

Further, the free end portion 334K has a guide portion 334P. The guide portion 334P is arranged so as to extend outward in the radial direction of the developing roller 331 from the tip end portion of the facing surface 334L, and guides a part of the toner conveyed by the developing roller 331 outward in the radial direction. In other words, the guide portion 334P is formed by bending the tip portion of the regulation blade 334 to approximately 90 ° C.

An example of the parameters of the regulation blade 334 in this embodiment will be described with reference to FIG. 4 again. As described above, the regulation blade 334 has its fixed end 334J held (fixed) by the blade holding portion 335, and the free end 334K is curved on the peripheral surface of the developing roller 331, for example, 30 to 50 N /. It is pressed with a linear pressure of m. The blade holding portion 335 is made of SECC (Steel Electrolytic Cold Commercial: electrogalvanized steel plate) having a thickness of 1.2 mm. The regulation blade 334 is a plate material made of SUS304CHP1H and having a wall thickness of 0.1 mm, and is yag welded to the blade holding portion 335. The regulation blade 334 extends from the blade holding portion 335 with a free length of 8.4 mm, and the pressure contact angle with respect to the developing roller 331 is set to 22 degrees. Further, the above-mentioned guide portion 334P is formed by bending the tip portion of the regulation blade 334 at a right angle at R0.3 mm. Further, the amount of bite into the developing roller 331 of the regulation blade 334 is 0.94 mm, and the amount of protrusion is 0.5 mm (see FIG. 4). That is, the regulation blade 334 according to the present embodiment has a protruding portion that protrudes toward the tip end side from the contact portion CP and is arranged apart from the developing roller 331, and the protruding portion is not on the tip end side. It constitutes a contact portion RP1 and a guide portion 334P.

Further, in the present embodiment, the facing surface 334L of the regulation blade 334 has the following surface roughness. The surface roughness of the facing surface 334L is continuously set to be small along the blade extending direction (direction from the fixed end portion 334J toward the free end portion 334K) from the fixed end portion 334J to the free end portion 334K. As a result, the surface roughness of the base end side non-contact portion RP2, the contact portion CP, and the tip end side non-contact portion RP1 is continuously set to be small along the blade extending direction. As a result, the surface roughness of the contact portion CP is set to be smaller than the surface roughness of the base end side non-contact portion RP2. At this time, it is desirable that the surface roughness Ra (arithmetic mean roughness) of the contact portion CP is set in the range of 0.02 or more and 0.1 or less, and is set in the range of 0.04 or more and 0.08 or less. Is even more desirable. The above-mentioned "continuously small" may be set so as to be linearly gradually reduced, or may be set so as to be curvedly gradually reduced.

The flow of toner around the regulation blade 334 will be described with reference to FIG. As described above, the developing roller 331 and the supply roller 332 are rotated in opposite directions at the supply nip, and the toner involved in development moves the peripheral surface of the developing roller 331 from the supply roller 332 to the regulation blade 334. The toner located around the developing roller 331 and the feeding roller 332 also moves in the direction of the direction, in accordance with the rotation of the developing roller 332 and the developing roller 331. Some toner that has reached the tip (free end 334K) of the regulating blade 334 on the peripheral surface of the developing roller 331 does not enter the gap between the regulating blade 334 and the developing roller 331 and follows the guide portion 334P. However, the toner in the portion relatively close to the developing roller 331 enters the gap between the regulating blade 334 and the developing roller 331. Such a flow of toner produces a force that opposes the force that the regulating blade 334 presses against the developing roller 331, that is, a force that lifts the regulating blade 334. A toner thin layer is formed at the contact portion CP by the force for lifting the regulation blade 334 and the elastic force for the regulation blade 334. However, when the developing device 33 is used for a long time, toner adheres to the regulation blade 334, making it difficult to supply toner to the downstream side, and the amount of toner supported on the peripheral surface of the developing roller 331 is small, causing thin streaks. do. The portion where the thin layer streaks are generated becomes white streaks on the image because toner is not supplied to the latent image on the photoconductor drum 31.

Further, when toner adheres to and accumulates on the tip side non-contact portion RP1 on the upstream side of the contact portion CP of the regulation blade 334, the toner carried on the peripheral surface of the developing roller 331 and conveyed toward the regulation blade 334 is removed. Since it cannot enter the nip portion (contact portion CP) of the regulation blade 334, the toner layer is not formed and thin streaks are likely to occur.

In order to solve such a problem, in the present embodiment, the regulation blade 334 has a vibration promoting portion. FIG. 6 is an enlarged view of an end portion of the regulation blade 334 of the developing device 33 according to the present embodiment. FIG. 7 is an enlarged exploded perspective view of an end portion of the regulation blade 334 of the developing apparatus 33 according to the present embodiment.

As shown in FIGS. 6 and 7, in the present embodiment, a plurality of slits 334Q are formed in the tip side non-contact portion RP1 of the regulation blade 334. The plurality of slits 334Q are arranged at intervals in the axial direction of the developing roller 331 (in the longitudinal direction of the regulation blade 334). Further, the plurality of slits 334Q are formed by linearly cutting the tip end portion of the regulation blade 334 to the boundary between the tip end side non-contact portion RP1 and the contact portion CP. Although not shown in FIG. 7, a slit 334Q is also formed in the guide portion 334P described above. Further, as shown in FIG. 6, slits 334Q are not formed in the portions of both ends of the regulation blade 334 that are sandwiched between the felt seal 337 and the developing roller 331. Since this portion comes into contact with the peripheral surface of the developing roller 331, the slit 334Q prevents the peripheral surface of the developing roller 331 from being scratched or the peripheral surface being polished.

According to such a configuration, the plurality of slits 334Q (vibration promoting portions) provided in the tip side non-contact portion RP1 of the free end portion 334K are not in contact with the tip side due to the moving force of the toner conveyed by the developing roller 331. The vibration of the part RP1 is promoted. Therefore, when the toner starts to adhere to the contact portion CP of the regulation blade 334 or the tip side non-contact portion RP1, the toner is easily peeled off due to the vibration of the tip side non-contact portion RP1 and the growth of toner adhesion is suppressed. NS. As a result, it becomes possible to smoothly allow the required amount of toner to enter toward the contact portion CP and to charge the toner while restricting the toner layer amount in the contact portion CP, and the thin layer streaks and images on the developing roller 331. It is possible to prevent the occurrence of the white streaks on the top. Further, since the vibration promoting portion is provided in the non-contact portion RP1 on the tip side and does not directly vibrate the contact portion CP, the vibration may have a great influence on the toner layer amount regulation and charging in the contact portion CP. It is deterred. On the other hand, the vibration of the tip-side non-contact portion RP1 can give a slight vibration to the toner passing through the contact portion CP, so that when a small amount of toner is adhered to the contact portion CP, The slight vibration causes the toner to move along the axial direction, so that the occurrence of thin-layer streaks can be suppressed.

Further, in the present embodiment, the tip side non-contact portion RP1 can be easily vibrated by forming a plurality of slits 334Q (cut portions) in the tip side non-contact portion RP1. In particular, since the tip of the regulation blade 334 is divided into a plurality of pieces by the plurality of slits 334Q, each piece can vibrate, and the toner adhering to the regulation blade 334 can be easily removed. Is possible.

The surface roughness R of the contact portion CP is preferably set in the range of 0.002 or more and 0.1 or less, preferably 0.04 or more and 0.08 or less. In this case, the wax component and the external additive component are less likely to adhere to the fine uneven portion of the contact portion CP. As a result, the sticking at the contact portion CP is suppressed, and the toner sticking at the tip side non-contact portion RP1 on the upstream side is suppressed with the toner sticking at the contact portion CP as the core.

Further, in the base end side non-contact portion RP2 on the downstream side of the contact portion CP, if the surface roughness is too low, the toner is not retained and is easily transported to the downstream side. Toner becomes difficult to move between. Therefore, the chance that the toner in the upper layer comes into contact with the developing roller 331 is reduced, so that the amount of charge in the toner in the upper layer is reduced, and as a result, the toner layer is easily disturbed. Therefore, in the base end side non-contact portion RP2 on the downstream side of the contact portion CP, the surface roughness is set to be larger than that of the contact portion CP and the tip side non-contact portion RP1, so that the toner is released on the downstream side of the contact portion CP. It becomes easy to roll and the toner can be charged stably. Specifically, the surface roughness Ra of the base end side non-contact portion RP2 is set to be larger than 0.1.

As described above, it is desirable that the surface roughness of the contact portion CP is set to be smaller than the surface roughness of the proximal end side non-contact portion RP2 among the regulation blades 334 made of metal.

According to such a configuration, the surface roughness of the base end side non-contact portion RP2 is rougher than that of the contact portion CP, so that the toner between the base end side non-contact portion RP2 and the developing roller 331 rolls. The toner is easily and stably charged. As a result, it is difficult to apply excessive pressure to the toner in the contact portion CP on the upstream side of the base end side non-contact portion RP2, and the wax component of the toner and the external addition are applied to the fine uneven portion of the contact portion CP of the regulation blade 334. It becomes difficult for the agent component to adhere. As a result, the sticking of toner in the contact portion CP is suppressed, and the occurrence of toner sticking to the upstream non-contact portion RP1 on the upstream side centering on the toner sticking in the contact portion CP is suppressed, so that the tip side non-contact is suppressed. It is also possible to prevent the toner from sticking to the part RP1. Further, since the frictional force exerted by the regulation blade 334 on the toner at the contact portion CP can be reduced, it is possible to further prevent the toner from sticking to the regulation blade 334. As a result, it becomes possible to smoothly allow the required amount of toner to enter toward the contact portion CP over the entire axial direction of the developing roller 331, and thin-layer streaks and white streaks on the image are generated on the developing roller 331. Can be prevented.

Further, in the present embodiment, the surface roughness Ra of the contact portion CP is set in the range of 0.02 or more and 0.1 or less, more preferably 0.04 or more and 0.08 or less. There is.

According to such a configuration, the wax component and the external additive component are less likely to adhere to the fine uneven portion of the contact portion CP, and the toner sticking in the contact portion CP is further suppressed.

Further, in the present embodiment, the free end portion 334K of the regulation blade 334 has a guide portion 334P.

According to such a configuration, the excess toner that is conveyed on the developing roller 331 and reaches the regulating blade 334 is guided outward in the radial direction by the guide portion 334P, so that the toner is between the regulating blade 334 and the developing roller 331. Excessive toner is prevented from entering. As a result, it is possible to further prevent the toner from sticking to the contact portion CP. Further, the vibration of the tip-side non-contact portion RP1 can be further promoted by the impact when the toner collides with the guide portion 334P as the developing roller 331 rotates.

Further, even when a so-called low-temperature fixing toner in which the melt viscosity (Pa · s) of the non-magnetic one-component toner used in the developing apparatus 33 at 95 ° C. is set in the range of 10,000 or more and 20,000 or less is used, the regulation blade is used. It is possible to prevent the toner from sticking to the 334. That is, even if the toner has a relatively low melt viscosity and the viscosity tends to increase depending on the temperature inside the apparatus, it is possible to prevent the toner from sticking to the regulation blade 334.

Further, in the present embodiment, in the image forming apparatus 1 including the developing apparatus 33 adopting the non-magnetic one-component developing method as described above, white streaks (images) are formed on the image due to the adhesion of toner to the regulation blade 334. It is possible to prevent the occurrence of defects). Further, by combining the developing device 33 with a cleanerless system in which the photoconductor drum 31 is not provided with a cleaning device, it is possible to realize miniaturization and cost reduction in the image forming device 1.

Next, a preferred embodiment of the developing device 33 will be described with reference to examples. In addition, each subsequent Example was carried out under the following experimental conditions.
<Experimental conditions>
-Photoreceptor drum 31: OPC drum-Peripheral speed of the photoconductor drum 31: 118 mm / sec
Circumferential speed of developing roller 331: 182 mm / sec
-Development bias DC component: 350V
・ Supply bias DC component: 450V
-Surface potential of photoconductor drum 31: 640V
-Diameter of developing roller 331: 13 mm
-Diameter of photoconductor drum 31: 24 mm
-Average particle size of non-magnetic toner: 8.0 μm (D50)

Under the above experimental conditions, as a comparative example of FIG. 3, a regulation blade 334Z not provided with a vibration promoting portion is adopted, and a predetermined number of sheets (1000 sheets) are printed with 15% of half images in the image forming apparatus 1. As a result, thin streaks were generated on the image.

On the other hand, under the above experimental conditions, as an example of FIG. 3, a plurality of slits 334Q formed in the tip side non-contact portion RP1 of the regulation blade 334 are adopted, and the image forming apparatus 1 has the same as the above. Similarly, as a result of printing a predetermined number of sheets, no thin-layer streaks were generated on the image. Similar results were obtained with the regulation blade 334 provided with the plurality of openings 334R and the plurality of holes 334S described later in the non-contact portion RP1 on the tip side of the regulation blade 334.

In the above comparative example, the inventor of the present invention observed the toner sticking state of the contact portion CP of the regulation blade 334Z and the tip side non-contact portion RP1 when the thin layer streaks were generated. Specifically, when observed with a microscope (KH-8700 manufactured by HIROX) at a magnification of 50 times, it was confirmed that toner adhered to the contact portion CP of the regulation blade 334.

Further, since a transparent substance other than the toner was attached to the portion to which the toner was attached as described above, it was included in the toner as a result of analysis using infrared spectroscopy (abbreviated as IR). It was found that the wax component was attached to the contact portion CP and the tip side non-contact portion RP1.

Furthermore, when the particle size of the adhered toner was measured with the above-mentioned microscope at a magnification of 2000 times, it was confirmed that the toner of 2 to 4 μm was mainly adhered among the toners having a volume average particle size of 8 μm. Was done. Further, when the adhered toner was removed with an air gun, a recess of wax was observed in the portion of the regulation blade 334 to which the toner had adhered. From the above, it was inferred that the adhesion of the toner at the free end portion 334K of the regulation blade 334 was that the wax first adhered to the facing surface 334L, and the fine particles of the toner having a small particle size adhered on the wax. ..

On the other hand, in the regulation blade 334 according to the present embodiment represented by the embodiment, the contact portion CP and the tip side non-contact portion RP1 are characterized by the characteristics of the vibration promoting portion provided on the tip side non-contact portion RP1 of the free end portion 334K. As a result, the adhesion of the wax component of the toner was suppressed, and the toner was preferably prevented from adhering to the wax component and finally adhering to the wax component.

Although the developing device 33 and the image forming device 1 provided with the developing device 33 according to the embodiment of the present invention have been described above, the present invention is not limited to this, and for example, the following modified embodiment is adopted. be able to.

(1) In the above embodiment, the image forming apparatus 1 is provided with one developing apparatus 33, but the image forming apparatus 1 is a color image forming apparatus having development apparatus 33 corresponding to a plurality of colors. It may be.

(2) In the above embodiment, the development housing 330 of the developing apparatus 33 has been described in that the non-magnetic toner is stored inside, but a toner container and a toner cartridge that store the non-magnetic toner are provided separately from the developing housing 330. It may have.

(3) In the above embodiment, as the vibration promoting portion according to the present invention, a plurality of slits 334Q are formed in the non-contact portion RP1 on the tip side of the regulation blade 334, but the present invention is limited to this. It is not something that is done. FIG. 8 is an enlarged view of an end portion of the regulation blade 334 of the developing apparatus according to the first modification embodiment of the present invention. FIG. 9 is an enlarged exploded perspective view of the end portion of the regulation blade of the developing apparatus according to the present modification embodiment.

As shown in FIGS. 8 and 9, in the present embodiment, a plurality of openings 334R (cutouts) are formed as vibration promoting portions in the tip-side non-contact portion RP1 of the regulation blade 334. The plurality of openings 334R are arranged at intervals in the axial direction of the developing roller 331 (in the longitudinal direction of the regulation blade 334). Further, the plurality of openings 334R are formed by cutting out the tip of the regulation blade 334 in a rectangular shape up to the boundary between the tip-side non-contact portion RP1 and the contact portion CP. Although not shown in FIG. 7, the opening 334R is continuously formed in the guide portion 334P described above. Further, as shown in FIG. 8, an opening 334R is not formed in a portion of both ends of the regulation blade 334 that is sandwiched between the felt seal 337 and the developing roller 331. As described above, since this portion comes into contact with the peripheral surface of the developing roller 331, the opening 334R prevents the peripheral surface of the developing roller 331 from being scratched or polished. ..

As described above, in the present modification embodiment, since a plurality of openings 334R are formed in the tip side non-contact portion RP1, between the tip side non-contact portion RP1 and the developing roller 331 as the developing roller 331 rotates. A flow toward the outside in the radial direction of the developing roller 331 is formed in a part of the toner that has entered. As a result, a difference in the force acting on the tip-side non-contact portion RP1 in the radial direction is generated between the portion with the opening 334R and the portion without the opening 334R, and the tip-side non-contact portion RP1 is surely vibrated. Can be made to. That is, when the toner starts to adhere to the contact portion CP of the regulation blade 334 or the tip side non-contact portion RP1, the toner is easily peeled off by the vibration of the tip side non-contact portion RP1 and the growth of the toner adhesion is suppressed. .. As a result, it becomes possible to smoothly allow the required amount of toner to enter toward the contact portion CP and to charge the toner while restricting the toner layer amount in the contact portion CP, and the thin layer streaks and images on the developing roller 331. It is possible to prevent the occurrence of the white streaks on the top.

(4) Further, FIG. 10 is an enlarged view of the regulation blade of the developing apparatus according to the second modification embodiment of the present invention. FIG. 11 is an enlarged exploded perspective view of the regulation blade of the developing apparatus according to the present modification.

In the present embodiment, a plurality of hole portions 334S are formed as vibration promoting portions in the tip-side non-contact portion RP1 of the regulation blade 334. The plurality of holes 334S are arranged at intervals in the axial direction of the developing roller 331 (in the longitudinal direction of the regulation blade 334). Further, the plurality of holes 334S are formed by opening the tip of the regulation blade 334 in a circular shape. The shape of the hole 334S is not limited to a circular shape, and may be another shape such as a rectangle. Further, as shown in FIG. 8, holes 334S are not formed in the portions of both ends of the regulation blade 334 that are sandwiched between the felt seal 337 and the developing roller 331. As described above, since this portion comes into contact with the peripheral surface of the developing roller 331, the hole portion 334S prevents the peripheral surface of the developing roller 331 from being scratched or polished. ..

As described above, in the present modification embodiment, a plurality of hole portions 334S are formed as vibration promoting portions in the tip side non-contact portion RP1, so that the tip side non-contact portion RP1 and the developing roller 331 are formed as the developing roller 331 rotates. A flow toward the outside in the radial direction of the developing roller 331 is formed in a part of the toner that has entered between the and. As a result, a difference in the force acting on the tip-side non-contact portion RP1 radially outward occurs between the portion with the hole portion 334S and the portion without the hole portion 334S, and the tip-side non-contact portion RP1 is ensured. Can be vibrated. Therefore, as in the above-described embodiment and the first modification embodiment, the growth of toner sticking is suppressed, the required amount of toner is smoothly entered toward the contact portion CP, and the toner layer is formed in the contact portion CP. It is possible to charge the toner while controlling the amount, and it is possible to prevent the occurrence of thin-layer streaks on the developing roller 331 and white streaks on the image. Further, when a plurality of holes 334S are formed in the tip side non-contact portion RP1, the shape of the outer peripheral portion of the tip side non-contact portion RP1 can be maintained, so that the rigidity of the tip side non-contact portion RP1 becomes high. It is prevented from dropping.

1 Image forming device 31 Photoconductor drum 33 Developing device 330 Developing housing 330A Housing body 330B Housing lid 331 Developing roller 332 Supply roller 333 Stirring paddle 334 Restriction blade 334J Fixed end 334K Free end 334L Opposing surface 334Q Slit (vibration promoting part) )
334R opening (vibration promotion part)
334S hole (vibration promotion part)
334P Guide part 335 Blade holding part 336 Lower seal CP Contact part RP1 Tip side non-contact part RP2 Base end side non-contact part

Claims (9)

A developing housing that houses a non-magnetic one-component toner,
A developing roller made of an elastic body having a cylindrical shape, rotatably supported by the developing housing, arranged to face a predetermined photoconductor drum at a developing nip portion, and carrying the toner on a peripheral surface.
A metal regulating blade that includes a facing surface facing the developing roller, abuts on the peripheral surface of the developing roller on the facing surface, and regulates the amount of the toner layer on the developing roller.
With
The regulation blade
A fixed end fixed to the developing housing and
A free end portion that is located on the opposite side of the fixed end portion and is located upstream of the fixed end portion in the rotational direction of the developing roller, is arranged on the facing surface, and is pressed against the peripheral surface of the developing roller. However, the contact portion that contacts the peripheral surface along the axial direction of the developing roller and the tip side of the facing surface that is arranged on the distal end side of the contact portion and is arranged at a distance from the peripheral surface. Non-contact parts, free ends including,
A vibration promoting portion arranged in the tip-side non-contact portion and promoting vibration of the tip-side non-contact portion by the moving force of toner conveyed by the developing roller.
Has a developing device. The developing apparatus according to claim 1, wherein the vibration promoting portion is a plurality of cut portions formed in the tip-side non-contact portion at intervals in the axial direction. The developing apparatus according to claim 1, wherein the vibration promoting portion is a plurality of notches formed in the tip-side non-contact portion at intervals in the axial direction. The developing apparatus according to claim 1, wherein the vibration promoting portion is a plurality of holes formed in the tip-side non-contact portion at intervals in the axial direction. The developing apparatus according to any one of claims 1 to 4, wherein the surface roughness Ra of the contact portion is set in the range of 0.02 or more and 0.1 or less. The developing apparatus according to claim 5, wherein the surface roughness Ra of the contact portion is set in the range of 0.04 or more and 0.08 or less. The free end portion is arranged so as to extend from the tip end portion of the facing surface toward the radial outer side of the developing roller, and guides a part of the toner conveyed by the developing roller to the radial outer side. The developing apparatus according to any one of claims 1 to 6, further comprising a part. The developing apparatus according to any one of claims 1 to 7, wherein the melt viscosity (Pa · s) of the toner at 95 ° C. is set in the range of 10,000 or more and 20,000 or less. The developing apparatus according to any one of claims 1 to 8.
An image forming apparatus including a photoconductor drum in which an electrostatic latent image is formed on a surface and the toner is supplied from the developing roller.

Images