JPH0477775A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent toner from being attached and left on the inside wall surface of a toner hopper by providing a cylindrical cleaning member which is brought into contact with the inside wall surface of the lower part of the toner hopper and rotated in accordance with the rotation of a toner agitator. CONSTITUTION:The toner agitator 53 is provided on the lower part of the toner hopper 50 and the rotating position thereof is set so as to bring the cleaning member 54 into contact with the inside wall surface of the lower part of the hopper 50. On the other hand, a toner residual quantity detection sensor 56 consisting of a magnetic sensor is provided near the outside wall of the lower part of the hopper 50 and it detects the residual quantity of the toner at a position near the inside wall surface of the hopper 50 which is cleaned by the cleaning member 54. Then, a control part, which receives the detected result of the detection sensor 56, drives a toner replenishment motor and replenishes the toner to the toner hopper 50.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image forming apparatus of a type in which, for example, a toner agitator stirs toner and carrier in a toner hopper to triboelectrically charge the toner.

An example of this type of image forming device is a printer, which uses two components consisting of toner and carrier to supply toner to an electrostatic latent image formed on a photoreceptor drum to obtain a visible image. The system developer is stirred by a toner agitator in a toner hopper, and the toner is triboelectrically charged.

On the other hand, regarding the replenishment of toner consumed as the development process progresses, the surface height of the developer in the toner hopper is lowered, and this is detected by a remaining toner amount detection sensor and toner is replenished. When a magnetic toner such as the two-component developer described above is used as the toner, a magnetic sensor (remaining toner amount detection sensor) is installed close to a predetermined position on the lower outer wall of the toner hopper to detect the amount of remaining toner. I do.

Note that the tip of the toner agitator rotates at a position relatively far away from the inner wall surface of the toner hopper facing the magnetic sensor.

However, in the conventional example described above, magnetic toner may adhere and accumulate at the position on the inner wall surface of the lower part of the toner hopper where the magnetic sensor should detect the amount of remaining toner due to moisture or other factors, which may cause problems during development. Even though the surface height position of the agent is below the detection area of the magnetic sensor, if it is in the detection area, there is a risk of erroneous detection.

The present invention has been made in view of the current situation, and corresponds to the detection area of the remaining toner amount detection sensor] - It is possible to prevent toner from adhering and remaining on the inner wall surface of the toner hopper, and as a result, the remaining amount of toner can be reduced. An object of the present invention is to provide an image forming apparatus that can perform accurate detection.

The present invention includes a toner hopper, a rotating toner agitator provided in the l/nahosoba, and a remaining toner amount detection sensor attached to the outer wall of the nahosoba. The present invention is characterized by comprising a cylindrical cleaning member that is fitted over the agitator and removes toner adhering to the detection surface of the detection sensor as the agitator rotates.

]Y-November 1 According to the above configuration, as the toner agitator rotates, the cylindrical cleaning member rotates near the inner wall surface of the lower part of the toner hopper or in contact with the inner wall surface of the lower part of the toner hopper, thereby reliably cleaning the inner wall surface of the lower part of the toner hopper. Therefore, no toner remains attached to the inner wall surface of the lower part of the toner hopper.

EXAMPLE 1 17- Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a side sectional view showing an embodiment in which an image forming apparatus according to the present invention is applied to a printer. The schematic configuration will be described below with reference to the drawings.

When a print switch (not shown) is turned on, the photosensitive drum 2 provided in the center of the device rotates in the direction shown by arrow A.
Along with this, the charger 3 charges the surface of the photoreceptor drum 2. Next, an optical writing unit 4 consisting of an LED array
emits light in response to an image signal given from a scanner section (not shown), exposing the surface of the photosensitive drum 2. Thus,
An electrostatic latent image is formed in the exposed area.

Next, a developing device 5 installed at the upper right of the photoreceptor drum 2 in the figure supplies toner to the electrostatic latent image to form a toner image (visible image).
form. That is, in the developing device 5, the two-component developer supplied into the toner hopper 50 is transferred to the toner agitator 53.
After the toner is triboelectrically charged by stirring, the charged toner is made into a thin layer by a developing sleeve 51 and a toner thinning blade 52, and then supplied to the photoreceptor drum 2. Note that details of the toner agitator 53 will be described later.

Meanwhile, in synchronization with the image forming process, the paper feed roller 7 feeds out the paper (not shown) stored in the paper feed cassette 8,
It is supplied to the registration roller 9.

The registration rollers 9 transport the paper to the transfer device 6 in synchronization with the rotation of the photosensitive drum 2.

The transfer device 6 transfers the toner image formed on the photosensitive drum 1 onto a sheet of paper. The paper P onto which the toner image has been transferred is then conveyed to the position of the fixing roller 10, where a fixing process is performed. After the fixing process, the paper is conveyed in a U-turn by a vapor guide 11 and a discharge roller 12, and is discharged onto a paper discharge tray 13 attached to the upper part of the main body. In addition,
In the figure, the path line P of the paper is indicated by a dashed line.

Next, details of the toner agitator 53 and its surroundings will be explained according to FIG. However, FIG. 2 is a perspective view showing the structure of the toner agitator 53. As shown in the figure, the toner agitator 53 has a crank shape and has an eccentric shaft portion 53b that is eccentric with respect to shaft portions 53a, 53a at both ends that serve as the center of rotation.

In addition, a cylindrical cleaning member 54 made of rubber, resin, or the like is attached to the center of the eccentric shaft portion 53b. In this installation, the cleaning member 54 is attached to the eccentric shaft portion 53b.
This is done by locking positioning rings 55.55 such as E-rings into grooves 57.57 provided on both left and right sides of the cleaning member 54 of the eccentric shaft portion 53b.

When the cleaning member 54 is shaped like a cylinder and is locked using the positioning rings 55, 55, there is an advantage that the cleaning member 54 can be easily replaced if it becomes worn.

The toner agitator 53 is provided at the lower part of the toner hopper 50 as shown in FIG. ). On the other hand, a first
As shown in the figure, a toner remaining amount detection sensor 56 consisting of a magnetic sensor is provided, and there is residual toner M (presence or absence) in the vicinity of the inner wall surface of the toner hopper 50 that has been cleaned by the cleaning member 54 (the area cleaned by the cleaning member 54). ) is detected. Then, a control section (not shown) that receives the detection result from the l/toner remaining amount detection sensor 56 drives a toner replenishment motor (not shown) to replenish the toner hopper 50 with toner.

FIGS. 3 and 4 are cross-sectional views showing modified examples of the cleaning member 54. FIG. Cleaning member 54 shown in FIG.
is a magnetic bushing 54a made of ferrite tube.
is fitted into the center of the eccentric shaft portion 53b of the toner agitator 53. According to the cleaning member 54, the toner adhering to the lower inner wall surface of the toner hopper 50 can be attracted and removed by magnetic force in a non-contact state. Therefore, the inner wall surface of the toner hopper 50 is not damaged.

Further, in the cleaning member 54 shown in FIG. 4, a magnet sleeve 54b having an inner diameter larger than the diameter of the eccentric shaft portion 53b of the toner agitator 53 is loosely fitted onto the eccentric shaft portion 53b. According to this cleaning member 54, since the magnetic sleeve 54b freely rotates the eccentric shaft portion 531] in accordance with the rotation of the toner agitator 53,
The entire circumferential surface of the magnetic sleeve 54b can be effectively used for cleaning.

Since the present invention has been described above, the cylindrical cleaning member reliably cleans the lower inner wall surface of the toner hopper as the toner agitator rotates, so that no toner remains attached to this portion.

Therefore, the remaining toner amount detection sensor does not erroneously detect the remaining amount of toner.

Moreover, it has the advantage that it can be realized with a simple structure.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing an embodiment in which the image forming apparatus according to the present invention is applied to a printer, FIG. 2 is a perspective view showing the structure of a toner agitator, and FIGS. 3 and 4 are modifications of the cleaning member. FIG. 3 is a cross-sectional view showing an example. 1-Printer, 5-Developer, 50-Toner hopper, 5
3-toner agitator, 54-cleaning member, 56
- Magnetic sensor. Figure 2

Claims (1)

[Claims] (1) a toner hopper, a rotating toner agitator provided in the toner hopper, a toner remaining amount detection sensor attached to the outer wall of the toner hopper, and a toner remaining amount detection sensor that is fitted over the agitator and detects the amount of remaining toner as the agitator rotates. An image forming apparatus comprising: a cylindrical cleaning member that removes toner adhering to a detection surface.