JPS61132971A - Toner replenishing device for copying machine - Google Patents

Abstract

PURPOSE:To avert the unbalance of toner concn. with a simple improvement by rotating respectively a main roller or auxiliary roller in accordance with the information from main and auxiliary sensors for detecting toner concn. and assuming different forms of supplying a toner. CONSTITUTION:A driving gear G rotates and the main roller A revolves to supply the toner (a) in a replenishing part 6 to a developing case 2 when the sensor S1 corresponding to the roller A emits the information on the decrease of the toner concn. while a solenoid S is held de-energized. On the other hand, the solenoid S is excited when the sensor S2 emits the information on the decrease of the toner concn. The auxiliary roller B is thereby rotated in synchronization with the roller A and the toner (a) in the replenishing part 6 is supplied to the case 2, by which the unbalance of the concn. is averted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a toner replenishing device for a copying machine.
This invention relates to a toner replenishing device that includes a sensor that detects the toner concentration of a two-component developer that is a mixture of carrier and toner, and a toner supply roller that supplies toner in a toner replenishment unit based on information about a decrease in toner concentration from the sensor. It is something.

(Prior Art) First, let's talk about the copying formats: the so-called one-end based copying format, in which two adjacent sides of the document table are used as the reference for placing the document; There is a so-called center-based copying mode in which the center lines of the crests are aligned, and a so-called variable-reduction copying mode in which the original is further reduced or enlarged.

When performing one-end reference copying, a paper feeding configuration is adopted in which one side edge of the copy paper is passed through one end side of the photosensitive drum, and in center reference copying, a paper feeding configuration is adopted in which the center of the copy paper is passed through the center of the photosensitive drum. In this case, the above-mentioned two types of paper feeding modes are selected during variable-magnification copying.

Therefore, depending on the size of the original and the ratio of magnification, an electrostatic residue may be formed on a part of the photosensitive drum, and the electrostatic residue may be formed on a portion of the developing sleeve where the electrostatic latent image is not formed. There is no consumption of toner in the developing sleeve, and as a result, the toner concentration becomes unbalanced in the longitudinal direction of the developing sleeve.

On the other hand, conventional toner replenishing devices dispose one toner concentration detection sensor corresponding to, for example, the center of one toner supply roller, and based on the information of the decrease in toner concentration from this sensor. The toner supply roller is rotated to supply toner to the developing case over the entire length of the developing sleeve.

For this reason, the toner concentration is higher on the end side of the developing sleeve where toner consumption is lower, and when an image is copied onto the maximum size or similar size copy paper, there may be a density difference in the width direction or due to toner overflow. The occurrence of background fogging was unavoidable.

(Problems to be Solved by the Invention) It is an object of the present invention to avoid the above-described imbalance in toner density through simple improvements and to improve copying performance.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a toner replenishing device for a copying machine described at the beginning, in which the toner supply roller is arranged in the same direction as the main roller and one or two in the axial direction. and a sub-roller, and main and sub-sensors for toner concentration detection are arranged in correspondence with the main roller and at least one sub-roller, respectively, and the main roller and the sub rollers are configured to be rotated based on information from the sub sensor.

(Function) According to the above characteristic structure, it is possible to supply toner by the main roller and toner by the sub roller, and to suppress the imbalance of toner concentration in the longitudinal direction of the developing sleeve. becomes possible.

(Embodiment) Hereinafter, embodiments of the present invention will be described based on the drawings. FIGS. 1 and 2 show a developing device intended for a copying machine capable of variable magnification copying that uses a center-based copying mode. For convenience, it is assumed that it is possible to make copies up to A8 size, and that the longitudinal direction of the copy paper is oriented toward the paper feeding direction during variable-magnification copying.

In the figure, 1 is a photosensitive drum, and 2 is a developing case, which accommodates a two-component developer 3 containing a mixture of toner a and carrier b. A developing sleeve 4 rotates in the opposite direction to the photosensitive drum 1, and a magnet 5 is fixedly provided inside.

Reference numeral 6 denotes a toner replenishing section connected to the upper part of the developing case 2, in which a toner flow lower part communicating with the case 2 is formed on the lower side, and a toner supply roller 8 is installed in a state where the toner flow lower part is closed. It is arranged.

Reference numeral 9 denotes a stirring tool having plate-like members C . Two sensors 81 for detecting the toner concentration of the developer 8.
8g is provided near the ear cutting member 10.

The toner supply roller 8 has a length corresponding to the short side dimension of A8 size copy paper, and as shown in FIGS. 2 and 8, for example, the length corresponds to the short side length of A4 size copy paper. It is divided into a main roller A in the center and the remaining sub rollers B and B on both sides, and each roller A, B and B has a cylindrical body 8a supported by a drive shaft 11 and a cylindrical body 8a provided on the cylindrical body 8a. The toner concentration detection sensors 81+82 are made of a soft cylindrical member 8b such as a sponge, and are provided at the center of each of the main roller A and one of the sub rollers B, respectively.

Each of the cylindrical bodies 8a... is supported by the drive shaft 11 through a cylindrical bearing 12 fixed to the cylindrical body 8a, and the cylindrical bearing 12 of the main roller A. for,
The drive shaft 11 is formed with slits e, e for fitting and locking the continuous drive blades d, a, and the rotation of the drive shaft 11 is prevented regardless of the movement of the drive shaft 11 in the axial direction. The main roller is rotated in conjunction with this.

On the other hand, slits g9g are formed in the cylindrical bearings 12 of the secondary rollers B and B on both sides, and the slits g9g are formed in the cylindrical bearings 12 of the sub-rollers B and B on both sides, through which the driving blades f and f connected to the drive shaft 11 pass, and A driven plate portion, h, to which the wing bodies f, f engage and disengage as they move;
is connected to the cylindrical bearing 12.

A bracket 18 is provided on one end side of the drive shaft 11.
One end of an arm 14 pivotally attached to is connected to the elongated hole 1 through a pin j, and the plunger 16 of a solenoid S, which is reset by a spring 16, is connected to the elongated hole at the other end of the arm 14. and bin l.

Further, on the other end side of the drive shaft 11, the solenoid S
Regardless of the movement of the drive shaft 11 in the axial direction by the spring 16 and the spring 16, a driven gear Gl that always engages with the drive gear G is connected. When the sensor S1 corresponding to the roller ram issues information on a decrease in toner concentration, the drive gear G rotates based on this information, and the main roller A is rotated.
The toner a in the replenishing unit 6 is supplied to the developing case 2 from the section , and when the sensor S2 corresponding to the auxiliary roller B issues information on a decrease in toner concentration in the above-mentioned toner supply state, the solenoid is activated based on this information. S is energized, which causes rollers B on both sides.

B rotates synchronously with the main roller, and all main and subrollers A,
Toner a in the replenishing section 6 is supplied to the developing case 2 from B and B.

Alternatively, when only the sensor S2 corresponding to the sub-roller B issues information on a decrease in toner concentration, the solenoid 8
is excited and the drive gear G is rotated, and all rollers A and B are rotated in the same way as above.

Toner a is supplied from B to the developing case 2.

Then, when a predetermined toner concentration is reached, the low drive is stopped, and if the solenoid S is energized, it is demagnetized.

Incidentally, although a disc-shaped collar 16, 16 made of synthetic resin is provided between the main and sub rollers A and B, this may be omitted.

In addition, in order to rotate the dissection rollers B and B in synchronization with the main roller, a combination structure was used in which the driving blades f and f and the driven plate parts h to which these blades engage and disengage. As shown in part, an electromagnet 17 is provided at the end of the main roller A, and a magnetic member 18 is provided at the end of the sub roller B, and the electromagnet 17 is activated by information from a sensor S2 corresponding to the sub roller B. Modifications such as excitation are possible, and the above configuration has the advantage that the drive shaft 11 does not need to be slid.

Further, in a copying machine that takes the above-mentioned one-end based copying mode, it is sufficient to adopt a roller split structure in which the sub roller B is provided at one end side of the main roller A, Cζ, as shown in FIG.

Further, as a divided configuration of the toner supply roller 8, the copy paper is roughly divided into an A-row small size group and a 3-row size group, and the main roller A has a length corresponding to the 3-row type group. Subroller B corresponding to the difference between row A and row B
In other words, the lengths of the main and sub rollers can be set arbitrarily depending on the copy mode and paper feeding mode.

(Effects of the Invention) As explained above, the toner replenishing device of the present invention can reduce the amount of toner erased at the developing sleeve portion depending on the copy paper size.
This was done by focusing on the fact that Mk is different, and the toner supply roller is divided into a main and sub roller so that toner is not unnecessarily supplied to areas where toner consumption is low. This makes it possible to suppress the imbalance of toner rectification in the longitudinal direction of the developing sleeve, which in turn makes it possible to suppress the occurrence of background fog and shading on a sheet of copy paper.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; FIG. 1 is a longitudinal sectional view of a developing device, FIG. 2 is a plan view of a toner supply roller, and FIG. 3 is a longitudinal sectional view of the toner supply roller. FIG. 4 is a partial cross-sectional view of another embodiment showing a drive structure for the sub roller, and FIG. 5 is a plan view of another embodiment showing a divided structure of the toner supply roller. 8... Two-component developer, 6... Toner supply section, 8...
- Toner supply roller, a...toner, b...carrier, A...main roller, B...subroller, 81. s2
...Toner concentration detection sensor.

Claims (1)

[Claims] A toner replenishing device consisting of a sensor that detects the toner concentration of a two-component developer that is a mixture of carrier and toner, and a toner supply roller that supplies toner in a toner replenishment section based on information about a decrease in toner concentration from the sensor. The toner supply roller is divided into a main roller and one or two sub rollers in the axial direction, and a main roller for toner concentration detection is provided corresponding to each of the main roller and at least one sub roller. and a sub-sensor, the main roller is rotated based on information from the main sensor, and the sub-roller is rotated based on information from the sub-sensor, respectively. Toner supply device for copying machines.