JP-7855879-B2 - Developing apparatus and image forming apparatus

Inventors

• 角谷 穂高
• 加藤 篤司

Assignees

• ブラザー工業株式会社

Dates

Publication Date

20260511

Application Date

20220316

Claims (11)

1. Developing roller and A supply roller that supplies toner to the developing roller, A housing having a toner storage chamber for storing toner, and a developing chamber in which the developing roller and the supply roller are arranged, A toner scraping body is placed in the developing chamber and contacts the supply roller to scrape off toner adhering to the surface of the supply roller, The toner storage chamber includes an agitator that rotates within the toner storage chamber to agitate the toner, The toner storage chamber and the developing chamber are arranged in the front-to-back direction. The housing is positioned between the toner storage chamber and the toner scraping body in the front-rear direction and has a rib that can contact the tip of the agitator, and the rib is provided so as to be separated from the tip of the rotating agitator at a point above the lower end of the toner scraping body . The inner wall surface of the housing has a lower inner wall surface located below the supply roller and the toner scraping body. The ribs protrude upward from the lower inner wall surface and extend along the front-rear direction toward the toner scraping body. A developing apparatus characterized in that a plurality of the ribs are arranged at intervals from one another in the width direction parallel to the rotation axis of the agitator .
2. The developing apparatus according to claim 1 , wherein the upper end of each rib is located above the lower end of the toner scraping body.
3. The developing apparatus according to claim 2 , wherein the upper end of each rib is located above the upper end of the toner scraping body.
4. The developing apparatus according to claim 2 or 3 , wherein the upper end of each rib is located below the rotation axis of the agitator.
5. The developing apparatus according to claim 4 , wherein the upper end of each rib is located below the upper end of the supply roller.
6. The developing apparatus according to any one of claims 1 to 5, wherein each of the ribs includes a plurality of inclined ribs that are inclined to approach the center in the width direction as they move from the developing chamber toward the toner storage chamber in the front-rear direction.
7. The developing apparatus according to claim 6 , wherein each of the ribs is located more centrally in the width direction than each of the inclined ribs and includes a central rib that extends parallel to the front-rear direction.
8. The developing apparatus according to any one of claims 1 to 7, wherein the distance between two adjacent first ribs located on the outer side in the width direction is greater than the distance between two adjacent second ribs located in the center in the width direction than the distance between the first ribs.
9. The developing apparatus according to any one of claims 1 to 8 , wherein the toner scraping body is a roller rotatably supported in the housing.
10. The developing apparatus according to any one of claims 1 to 9 , wherein the contact surface of each rib that contacts the tip of the agitator inclines upward toward the toner scraping body in the front-rear direction and reaches the upper end of each rib.
11. Photoreceptor and A developing apparatus according to any one of claims 1 to 10 , which supplies toner to the photoreceptor, An image forming apparatus characterized by comprising:

Description

This invention relates to a developing apparatus and an image forming apparatus. Figure 3 of Patent Document 1 discloses an example of a conventional developing apparatus. This developing apparatus is provided together with a photosensitive drum in an electrophotographic printer, which is an example of an image forming apparatus. This developing device comprises a toner carrier as a developing roller, a sponge roller as a supply roller, a toner cartridge as a housing, and a toner stirring shaft as an agitator. The sponge roller supplies toner to the toner carrier. The toner cartridge has a toner storage chamber for containing toner and a developing chamber where the toner carrier and sponge roller are located. The toner agitation shaft rotates within the toner storage chamber to agitate the toner. As shown in Figure 1 of Patent Document 1, the developing apparatus further includes an auxiliary roller as a toner scraping body. The auxiliary roller contacts the sponge roller and scrapes off the toner adhering to the surface of the sponge roller. The developing unit supplies toner to the photoreceptor drum using this configuration. During this process, the developing unit stabilizes the amount of toner supplied to the toner carrier by the sponge roller by having an auxiliary roller scrape off excess toner from the sponge roller. Japanese Patent Application Publication No. 11-15246 This is a schematic cross-sectional view of an image forming apparatus equipped with the developing device of the embodiment.This is a schematic cross-sectional view of the developing apparatus of the embodiment.This is a partial top view showing multiple ribs and other features as seen from the direction Z, as indicated by the arrow in Figure 2.This is a schematic cross-sectional view of a developing apparatus according to an embodiment, showing the state in which the tip of a rotating agitator moves while being constrained by a rib it is in contact with.This is a partially schematic cross-sectional view similar to Figure 4, showing the behavior of the tip when the rib separates from the tip of the agitator. The following describes embodiments of the present invention with reference to the drawings. (Examples) As shown in Figure 1, the developing apparatus 3 of the embodiment is an example of a specific embodiment of the developing apparatus of the present invention. The developing apparatus 3 is provided in the image forming apparatus 1. The image forming apparatus 1 is a monochrome laser printer that forms an image on a sheet SH using an electrophotographic method. The image forming apparatus 1 comprises a main body 9, a sheet supply unit 20, a developing unit 3, a photoreceptor 5, a scanner unit 8, a fixing unit 7, and an ejection unit 29. The main body of the device 9 is roughly box-shaped and contains several frame members (not shown) inside. A sheet cassette 9C is detachably provided in the lower part of the main body 9. Inside the sheet cassette 9C, image-forming sheets SH are stored in a stacked state. The sheets SH are paper, OHP sheets, etc. A discharge tray 9D is provided on the top surface of the main body 9 of the apparatus. The completed image-forming sheets SH are discharged into the discharge tray 9D. A sheet supply unit 20 is provided at the front of the main body 9. The sheet supply unit 20 transports the sheets SH contained in the discharge tray 9D to the developing unit 3. A fixing unit 7 is provided at the rear of the main body 9. The fixing unit 7 heats and pressurizes the sheets SH that have passed through the developing unit 3. A transport path P1 is provided within the main body 9 of the device. The transport path P1 starts from the front end of the sheet cassette 9C, makes an upward U-turn, passes through the sheet supply unit 20, then proceeds approximately horizontally backward through the developing unit 3 and the fixing unit 7, and then makes another upward U-turn, passing through the discharge unit 29 to reach the discharge tray 9D. The sheet supply unit 20 feeds the sheets SH contained in the sheet cassette 9C one by one to the transport path P1 using the feed roller 21, separation roller 22, and separation pad 22A. The sheet supply unit 20 then transports the sheets SH towards the developing device 3 using the transport roller 23A and pinch roller 23P, and the register roller 24A and pinch roller 24P, which are arranged along the transport path P1. The photoreceptor 5 and the developing device 3, which supplies toner T1 to the photoreceptor 5, constitute a so-called developing cartridge, and are detachably mounted on the main body 9 of the device. As shown in Figure 2, the developing apparatus 3 has a housing 40. The housing 40 is formed by combining multiple resin molded parts so as to partition the internal space. The housing 40 has a toner storage chamber 41 and a developing chamber 43 inside. The toner storage chamber 41 and the developing chamber 43 are aligned in the front-to-back direction. In