JPH0235312B2 - FUNTAIGENZOSOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a powder developing device, in particular, a powder one-component developer is coated in a uniform thin layer on a developer holding means disposed opposite to an image carrier, and the image carrier is held at the opposing position. The present invention relates to a powder developing device equipped with means for detecting the remaining amount of developer from a latent image on a body.

First, an outline of this type of powder developing apparatus will be explained with reference to FIG. Reference numeral 1 denotes a photosensitive drum as an electrostatic latent image carrier, which is attached to a body (not shown) so as to be rotatable in the direction of the arrow. 2 is a hopper which also serves as a storage container for a powder developer (hereinafter referred to as toner) 3; 4 is a toner holding means which is rotatably attached to the hopper 2 so that a portion thereof protrudes outside from the hopper opening 2a; The sleeve is made of non-magnetic stainless steel and faces the photosensitive drum 1, and has a circumferential speed of 100 mm/sec, which is approximately the same speed as the photosensitive drum. A magnet 5 is placed and fixed inside the sleeve 4, and its surface magnetic flux is approximately 800 Gauss. A blade 6 is disposed opposite the sleeve 4 on the sleeve advancing side of the opening 2a, and applies the toner 3 to the sleeve surface in a uniform thin layer 3a through a gap of about 0.3 mm formed between the blade 6 and the sleeve 4. Reference numeral 7 designates a toner remaining amount detecting means in the hopper 2, which uses a weight detecting element made of a piezoelectric element having a diameter of 20 φ, for example. Reference numeral 8 denotes a display circuit which receives the detection signal from the remaining toner amount detection means 7 and displays the necessity of toner replenishment.

When the sleeve 4 is rotated in the direction of the arrow by a drive mechanism (not shown), the toner 3 adheres to the sleeve surface by supporting forces such as magnetic force and electrostatic force and is conveyed in the same direction, and a part of it is transferred to the blade 6. collide with This colliding toner is pushed by the following toner and rises along the blade surface in the direction of the arrow in Figure 1, and when it rises to a certain height, it changes direction due to its own weight and becomes the same as shown by the arrow in Figures 2 and 3. Since the toner rotates at certain points, there are areas where toner consumption is high and toner consumption is low depending on the electrostatic latent image on the photosensitive drum, which causes development defects.

That is, it is necessary that the longitudinal dimension of the developing device has at least the maximum paper width that can be copied by a copying machine equipped with the developing device. However, when actually using a copying machine, originals of various sizes are copied,
Or, even if the originals are of the same size, there is variation in the reflection density of the original itself. Also, when copying a three-dimensional object, due to the depth of field of the copying machine's optical system, the original cover (the surface in contact with the original glass is usually The amount of toner consumed in the longitudinal direction of the sleeve 4 varies greatly depending on the purpose of use, since the floating part of the sleeve 4 (white) is equivalent to a solid black original. For this reason,
Even though the total amount of toner in the hopper 2 is sufficient, there are local streak-like areas of low development density or areas that are not developed at all in the developed image, resulting in poor development.

This developing defect cannot be completely solved even if the remaining amount detecting means 7 is provided in the hopper. In other words, the portion corresponding to the remaining amount detection means does not necessarily consume the most developer, and if the entire copying machine is installed at an angle, the remaining amount cannot be accurately detected because the developer is on one side. It is.

Conventionally, as a means to solve this problem, it has been known to drive and rotate a spiral screw in the developing device to agitate the developer, but the device is large and complicated, and the bearing part There is a risk of developer clogging.

The present invention has been proposed in view of the above, and an object of the present invention is to provide a powder developing device that does not cause poor development as long as the total amount of developer in the developing device is sufficient.

As a means for achieving this purpose, a deflection guide member 9 is provided which deflects the direction of motion of the colliding toner in the axial direction of the sleeve and divides the direction into two, and a remaining toner amount detecting means 7 is provided corresponding to the bisected position where the amount of toner is least. It is characterized by having the following.

The deflection guide member 9 is constructed by providing deflection guide pieces 90a and 90b on the toner collision surface of a substrate 90 disposed in the axial direction of the sleeve 4 to divide the toner into left and right halves. A deflection guide piece 90 is provided on the toner collision surface of the blade.
A and 90b may be provided.

In the illustrated example, as shown in FIG.
When installing two blades a and 90b on the left and right at an angle of about 30 degrees with an interval of 10 mm, the blades are attached to the blade 6 with a tendency to open upward so that a gap of 0.3 mm is formed between the blade and the sleeve surface. , deflection guide pieces 90a, 9
It is installed so that there is a gap of about 5 mm between 0b and the sleeve surface.

When the deflection guide member 9 is attached to the hopper 1 as the blade 6 shown in FIG. The sleeve 4 is deflected into two parts in the axial direction while being guided by the guide pieces 90a and 90b in a spiral manner, and a portion with the least amount of toner is formed at the boundary A. Since the remaining toner amount detection means 7 is provided corresponding to this boundary area A, by detecting the amount of toner at the boundary area A and replenishing toner, white lines etc. due to insufficient toner on the sleeve can be avoided. Occurrence can be prevented.

Therefore, when the developing device of the present invention was used to develop the latent image of a document with uneven toner consumption (a solid black image only in the back 50 mm of the sleeve, and the rest of the document being white), the solid black image was developed. The remaining toner amount detecting means 7 detects a decrease in the amount of toner in the boundary area A and replenishes toner before the corresponding portion with a large amount of toner consumption becomes toner insufficient, thereby preventing toner defects from occurring. . Furthermore, when copying is performed with the copying machine main body tilted approximately 3 degrees, the toner may be unevenly distributed, but toner replenishment is performed by the detection by the remaining toner amount detection means 7, and the amount of toner on the higher side is It did not decrease to the point where developing defects occurred.

As described above, the present invention provides a deflection guide member that deflects the moving direction of the colliding toner in the axial direction of the sleeve and divides it into two, and a remaining toner amount detection means is provided corresponding to the bisected position where the amount of toner is the smallest. Before toner shortage occurs on the sleeve due to uneven toner consumption, toner is replenished based on the detection signal from the remaining toner amount detection means, thereby preventing development defects. Furthermore, since the toner is deflected in the axial direction of the sleeve and agitated naturally, it is possible to reliably prevent the toner from clumping together without providing any special stirring means.

Note that the toner 3 is, for example, polystyrene 3.
A one-component magnetic toner having an average particle diameter of 15 μm, which is obtained by kneading and pulverizing 1 part by weight of magnetite, is used.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional side view of a powder developing device, FIG. 2 is an explanatory diagram of movement of colliding toner in a conventional powder developing device, FIG. 3 is a perspective view thereof, and FIG. 4 is a diagram showing a powder developing device of the present invention. FIG. 3 is an explanatory diagram of movement of colliding toner. 1 is an image carrier, 2 is a hopper, 3 is toner, 4 is a sleeve, 5 is a magnet, 6 is a blade, 7 is a toner remaining amount detection element, 8 is a display circuit, 9 is a deflection guide member, 90 is a substrate, 90a , 90b is a deflection guide piece.

Claims (1)

[Claims] 1 a developer holding means disposed opposite to the image carrier;
In a developing device having a blade for applying a powder mono-component developer onto the developer holding means in a uniform thin layer, and a developer remaining amount detection means for detecting the remaining amount of the mono-component developer, a collision occurs. A deflection guide member is provided that deflects the moving direction of the developer in the axial direction of the developer holding means and bisects the same, and the remaining developer amount detecting means is arranged in correspondence with the bisected position where the amount of one-component developer is the smallest. A powder developing device characterized by: