JPH0547957U - Development device - Google Patents

Abstract

(57) [Summary] [Purpose] It is possible to reduce the occurrence of image defects by supplying undeveloped toner to the developing roller in a reduced amount. [Structure] A first chamber 3 in which a developing roller 1 is installed, a second chamber 4 provided inside a photosensitive drum 2, and the first chamber 3 and the second chamber
A first passage 5 that connects the chamber 4, a toner feed spring 7 that feeds toner from the second chamber 4 to the first chamber 3 through the first passage 5, and a second passage that connects the first chamber 3 and the second chamber 4. The passage 6 and the toner return spring 8 for feeding the toner from the first chamber 3 to the second chamber 4 through the second passage 6 and the second chamber side opening of the first passage 5 are separated from each other to such an extent that the toner can be sufficiently charged. At the position or in the second passage 6, there is a replenishing port 11, and a toner replenishing means 9 for supplying the toner to the second chamber 4 is provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a developing device used in an image forming apparatus such as a copying machine, a fax machine, and a printer.

[0002]

[Prior Art]

 Conventionally, in an image forming apparatus such as a copying machine, in order to develop the electrostatic latent image of the original formed on the surface of the photoconductor into a toner image, a developing device as shown in FIG. Is provided close to. The developing device main body 30 of this developing device is provided with an opening 33 at a position close to the photosensitive drum 20, and the developing roller 1 having a magnet built therein is rotatably arranged in the opening 33. There is. Inside the developing device main body 30 on the opposite side of the developing roller 1 from the photosensitive drum 20, stirring rollers 31 and 32 for rotatably agitating the toner for charging the toner are rotatably arranged. Further, a replenishing port 34 for supplying toner is provided on the upper part of the developing device main body 30, and a toner replenishing roller 41 for replenishing toner to the developing device main body 30 is provided at the replenishing port 34. A toner hopper 40 for storing toner, which is provided in the, is connected.

When developing the electrostatic latent image formed on the surface of the photosensitive drum 20, first, the toner stored in the toner hopper 40 is supplied to the developing device main body 30 by the toner supply roller 41. The toner supplied to the developing device main body 30 is agitated by the rotation of the agitating rollers 31 and 32. For example, in the two-component magnetic brush development, the toner particles and the carrier made of magnetic particles are agitated sufficiently. The toner particles are charged and attached to the carrier by Coulomb and short-range Van der Waals forces. The toner charged by the agitation is sent to the image roller 1 side by the rotation of the agitation rollers 31 and 32, adhered to the surface thereof by the magnetic force of the developing roller 1, and sent to the photosensitive drum 20 side. When the toner on the developing roller 1 approaches the surface of the photosensitive drum 20, the toner adheres to the surface of the photosensitive drum 20 according to the charge of the electrostatic latent image to form a toner visible image.

[0004]

[Problems to be solved by the device]

 However, in the developing device as described above, the toner passing through the lower side of the stirring rollers 31, 32 is sufficiently agitated and the toner is easily charged, but the toner is supplied from the replenishing port 34 and the stirring roller 31 is supplied. , 32 passing through the upper side of the developing roller 1 and being sent to the developing roller 1 side are supplied to the developing roller 1 with a sufficient amount of uncharged toner, thus causing an image defect. There are challenges.

The present invention has been made in consideration of the above-mentioned problems of the related art, and an object thereof is to provide a developing device capable of supplying undeveloped toner to a developing roller in a state in which the amount of uncharged toner is small to reduce the occurrence of image defects. It is what

[0006]

[Means for Solving the Problems]

 According to the present invention, there is provided a first chamber having a developing roller therein, a second chamber separated from the first chamber, a first passage connecting the first chamber and the second chamber, and a first passage through the first passage. From the first chamber to the second chamber through the first toner feeding means for feeding the toner from the second chamber to the first chamber, the second passage connecting the first chamber and the second chamber, and the second passage. The second toner feeding means for feeding the toner through the first passage and the second chamber side opening of the first passage are provided at a position away from the second chamber side so that the toner can be sufficiently charged, or the second passage has a replenishment opening for feeding the toner. The developing device includes a toner replenishing unit that supplies the toner to two chambers.

[0007]

[Action]

 According to the present invention, the toner replenishing means has the replenishment port at a position away from the second chamber side port of the first passage to the extent that the toner can be sufficiently charged, or in the second passage. The toner feeding unit feeds the sufficiently charged toner from the second chamber to the first chamber, and the second toner feeding unit feeds the toner remaining after the development from the first chamber to the second chamber.

[0008]

Embodiments The present invention will be described below with reference to the drawings showing the embodiments thereof.

FIG. 1 is a sectional plan view of a developing device according to an embodiment of the present invention. That is, in a developing device used in an image forming apparatus such as a copying machine, in order to develop an electrostatic latent image of a document formed on the surface of the photosensitive drum 2 at a position close to the photosensitive drum 2, A developing casing 3 which is one chamber is provided, and an opening of the developing casing 3 is rotatably provided with a developing roller 1 incorporating a magnet for adhering toner to the surface thereof.

Inside the photosensitive drum 2, a stirring container 4 that is a second chamber that rotates according to the rotation of the photosensitive drum 2 is installed, and the stirring container 4 is separated from the photosensitive drum 2 by a partition 12. A hole is provided in the center of one end surface of the stirring container 4, and a hole is also provided in the end surface of the developing casing 3 on the same side as the hole. A toner return pipe 6, which is a second passage, is connected between the holes to return the toner from the developing casing 3 to the stirring container 4. Further, a hole is provided at the center of the other end surface of the photosensitive drum 2, and the hole provided on the other end surface on the side of the developing casing 3 on the same side as the hole means that toner is transferred from the stirring container 4 to the developing casing 3. It is connected by a toner feed pipe 5 which is a first passage for feeding.

To the inner wall of the agitating container 4 on the toner returning pipe 6 side, one end of a toner returning spring 8 which is a second toner feeding means for returning the toner from the developing casing 3 to the agitating container 4 is fixed. The spring 8 is inserted into the toner return pipe 6 up to the side of the developing casing 3. On the other hand, one end of a toner feeding spring 7 which is a first toner feeding means for feeding toner from the agitating container 4 to the developing casing 3 is fixed to the inner wall of the agitating container 4 on the toner feeding pipe 5 side, and the toner feeding spring 7 is The toner feeding tube 5 is inserted up to the side of the developing casing 3. A replenishment port 11 for supplying toner to the stirring container 4 is provided in the middle of the toner return pipe 6 on the side of the developing casing 3, and the replenishment port 11 has a toner replenishing means 9 having a toner replenishing roller 10. It is connected.

A gear 22 for rotating the photosensitive drum 2 is attached to the toner feed pipe 5 side of the photosensitive drum 2, and a driving gear 21 for driving the photosensitive drum 2 is attached to the gear 22 thereof. It is meshed.

Next, the operation of the above embodiment will be described.

First, as shown in FIG. 2, toner is supplied from the toner replenishing means 9 into the toner return tube 6 by the toner replenishing roller 10, and the photosensitive drum 2 is rotated in the direction of the arrow (solid line). Then, the toner return spring 8 is twisted with the rotation of the photosensitive drum 2 and rotates in the toner return tube 6, and the rotation brings about the effect of advancing the spiral of the toner return spring 8 from the developing casing 3 to the stirring container 4. The toner is supplied into the stirring container 4 inside the photosensitive drum 2. The toner carried to the stirring container 4 is sufficiently agitated by the rotation of the photosensitive drum 2. Then, when the toner is stored in the stirring container 4 up to the position of the toner feeding pipe 5, the toner is fed by the toner feeding spring 7 into the toner feeding pipe 5 contrary to the toner return spring 8, and further, the developing casing. It is sent within 3. The toner sent to the developing casing 3 is drawn into the toner returning tube 6 by the toner returning spring 8 on the other side of the developing casing 3. As described above, the toner is supplied from the toner replenishing means 9, and then circulates through the toner return pipe 6, the stirring container 4, the toner feed pipe 5 and the developing casing 3. At this time, the toner is agitated by the rotation of the photosensitive drum 2 in the agitating container 4, and also agitated and charged when it is moved by the toner return spring 8 and the toner feeding belt 7. When the toner is accumulated in the stirring container 4 and the developing casing 3 in a predetermined amount necessary for the development, the toner replenishment is stopped.

Next, when the electrostatic latent image formed on the surface of the photosensitive drum 2 is developed, as described above, due to the rotation of the photosensitive drum 2, the toner is agitated particularly in the stirring container 4 and sufficiently charged. , The toner is sent to the developing casing 3 and adsorbed by the developing roller 1, and the toner that approaches the electrostatic latent image by the rotation of the developing roller 1 (in the direction of the dotted arrow) is charged by the electrostatic latent image. Depending on the amount, the film is attached and developed. Since the photosensitive drum 2 always rotates during the development, the toner is constantly stirred and charged during that time, and the toner used for the development is sufficiently charged so that it does not cause an image defect. Become. Further, since the second chamber uses the agitating container 4 built in the photosensitive drum 2, the developing device becomes compact. Further, the reduction of uncharged toner also reduces the scattering of toner, and the amount of toner in the developing device can be increased, so that the toner deterioration is slowed down and the life is extended.

Although the toner replenishing port 11 is provided on the side of the developing casing 3 of the toner return pipe 6 in the above embodiment, the present invention is not limited to this, and it may be provided at any part of the toner return pipe 6 or with stirring. In the vicinity of the toner return pipe 6 side of the container 4 or the like, in short, it suffices to provide it at a position away from the second chamber side opening of the first passage to such an extent that the toner can be sufficiently charged.

Further, in the above embodiment, the second chamber is provided at a position apart from the first chamber by utilizing the empty space of the photosensitive drum 2, but the present invention is not limited to this, and for example, FIG. As shown in b), the casing provided with the developing roller 1 is divided into the first chamber 13 and the second chamber 14 by the partition walls 25, and the toner is transferred from the first chamber to the second chamber in both corners of the partition wall 25. The second passage 16 for sending the toner to the chamber may be provided on the lower side, and the first passage 15 for sending the toner from the second chamber to the first chamber may be provided on the upper side. The toner replenishing means 9 is provided above the second chamber 14 on the second passage 16 side. In this case, the first toner feeding means and the second toner feeding means are screwed by the toner feeding rollers 17 and 18 (for example, paddle rollers) provided at both ends of the screw roller 19 disposed on the second chamber side. It may be configured to rotate integrally with the roller 19 so that the toner can move as shown by the arrow.

[0018]

[Effect of the device]

 As is apparent from the above description, the present invention provides a first chamber in which a developing roller is provided, a second chamber separated from the first chamber, and a first chamber for connecting the first chamber and the second chamber. Through the passage and the first passage, the first toner feeding means for feeding the toner from the second chamber to the first chamber, the second passage connecting the first chamber and the second chamber, and the second passage. The second toner feeding means for feeding the toner from the first chamber to the second chamber and the second chamber side opening of the first passage at a position far enough to sufficiently charge the toner, or the second passage. Since a replenishment port is provided in the path and a toner replenishing means for supplying toner to the second chamber is provided, it is possible to reduce the occurrence of image defects by supplying undeveloped toner to the developing roller with a reduced amount. It has the advantage of being able to

[Brief description of drawings]

FIG. 1 is a cross-sectional plan view of a developing device according to an embodiment of the present invention.

FIG. 2 is a partially cutaway side view of the embodiment.

FIG. 3 (a) is a cross-sectional view of another embodiment in plan view, and FIG. 3 (b) is a cross-sectional view taken along the line AA.

FIG. 4 is a sectional view of a conventional developing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 developing roller 2 photosensitive drum 3 developing casing 4 stirring container 5 toner feeding pipe 6 toner returning pipe 7 toner feeding spring 8 toner returning spring 9 toner replenishing means 10 toner replenishing roller 11 replenishing port

Claims (2)

[Scope of utility model registration request] 1. A first chamber having a developing roller therein, a second chamber separated from the first chamber, a first passage connecting the first chamber and the second chamber, and a first passage through the first passage. A first toner feeding means for feeding toner from the second chamber to the first chamber, a second passage connecting the first chamber and the second chamber, and the second chamber through the second passage. From the second toner feeding means for feeding the toner from the second chamber toward the second chamber and the opening of the first passage on the side of the second chamber to a position in the second chamber that is sufficiently separated from the toner, or The second
A developing device having a replenishing port in a passage, and a toner replenishing means for supplying toner to the second chamber. 2. The developing device according to claim 1, wherein the second chamber is a container provided inside the photosensitive drum, and the container is rotated according to the rotation of the photosensitive drum.