JPS589170A - Toner replenishing device - Google Patents

Abstract

PURPOSE:To exactly detect the remaining quantity of a toner, and to replenish the toner, by utilizing the fact that agitation resistance of an agitator varies in accordance with the remaining quantity of the toner in a hopper. CONSTITUTION:To a shaft of an agitator 5 installed to a toner replenishing hopper 2, a disk 6 is fixed, also to its outside, a disk 7 formed in one body with a gear 9 is idly fitted so as to be freely rotatable, and both of them are connected with a spring 8. When the disk 7 is rotated by a motor 11, the agitator fixed to the disk 6 is rotated with a constant phase difference in a state that the spring 8 is stretched by resistance of the toner. As the remaining quantity of the toner becomes a little, the resistance is decreased, too, therefore, the toner can be replenished exactly by detecting a phase difference of both the disks as quantity of shift of optical marks 13, 14.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a toner supply device for an electrophotographic copying machine.

In an electrophotographic copying machine, the toner in the developer in the developing device is consumed as copies are made, so it is necessary to replenish the consumed toner in order to maintain the toner concentration in the developer within a predetermined concentration range. be. As a toner replenishment method, a quantitative replenishment method is widely used in which a fixed amount of toner is replenished according to the number and size of copies to control the density of the developer. As shown in FIG. 1, this type of toner replenishing device is generally provided with a replenishing roller 3 having an axial groove 6a on the outer periphery at the discharge port at the lower end of a hopper 2 that accommodates toner 1. used in When the replenishment roller 6 is rotated, the toner 1 at the bottom of the hopper is scraped out from the groove 3aK by the volume of the groove 3a and is replenished to the developing device. Therefore, the amount of replenishment is controlled by the number of rotations of the replenishment roller.

However, even if the volume of the groove 3a is the same, if the amount (height H) of the toner 1 in the hopper 2 changes, the filling density of toner in the groove changes. The replenishment amount fluctuates, and as shown in FIG. 2, it rapidly decreases near the toner end as the toner amount H decreases. However, conventional toner replenishment devices usually only detect and display the end of toner, so they cannot compensate for the fluctuations in the replenishment amount of the toner replenishment roller described above, and the constant replenishment method maintains the toner concentration of the developer at a constant level. It was difficult to keep it in place.

Also, as only the toner end is displayed, you may not know when to prepare replenishment toner in advance, or the machine may stop when the toner runs out while copying a large number of sheets, or if a large number of copies are made after the toner end is displayed. However, there were problems such as an extremely low toner density in the developer and the adhesion of carrier onto the photoreceptor and copy paper, resulting in abnormal images.

As a means of detecting and displaying the amount of toner remaining in the hopper, there is also a toner remaining amount display device that installs a float in the hopper and mechanically transmits the amount of movement of the float to a pointer and displays it. , toner replenishment hoppers are arranged at various positions on the copying machine, and the above-mentioned pointer cannot always be displayed in a position that is easy for the operator to see. Another drawback is that unlike liquids, powders such as toner cannot necessarily be detected with high precision using a float.

In view of the above-mentioned problems and drawbacks of the conventional toner replenishing device of an electrophotographic copying machine, the present invention uses a simple configuration to detect the amount of toner remaining in the hopper, thereby reducing the amount of toner remaining. Another object of the present invention is to provide a toner replenishing device capable of correcting errors in quantitative replenishment.
To provide a toner replenishing device which displays the number of copies that can be made or the remaining amount, and further issues a warning when the number of copies that exceeds the number of copies that can be made is specified.

Hereinafter, the present invention will be explained in detail with reference to drawings showing embodiments thereof.

3 to 5 are views showing an embodiment in which the present invention is applied to the toner replenishing device shown in FIG. A shaft 4 is rotatably supported on the shaft 4, and the hopper 2 is parallel to the shaft 4.
An agitator 5 is attached which is formed into a U-shape by a stirring part 5a extending over the entire width of the stirring part 5a and a connecting part 5b connecting both ends of the stirring part 5a to the shaft 4. The locus circle of the stirring part 5a is provided as close to the bottom of the hopper 2 as possible.

As shown in FIGS. 4 and 5, a disk 6 is fixed to the shaft 4 on the outside of the hopper 2, and a disk 7 is coaxially supported on the outside. A spring 8 is mounted between points near the outer periphery of each of the opposing surfaces of the two discs. A gear 9 is integrally attached to a disk 7 that is rotatable with respect to the shaft 4, and a gear 10 is connected to the shaft rotated by a drive motor 11 via a clutch CL.
are meshing together. The gear 10 also meshes with a gear 12 attached to the shaft of the supply roller 3.

Therefore, when the clutch CL is engaged while the drive motor 11 is rotating, the disc 7 is rotated via the gears 10 and 9. When the disk 7 rotates, the disk 6 also rotates via the spring 8, and the shaft 4 and agitator 5 rotate. In this case, the agitator 5 receives resistance from the toner 1, and with the spring 8 stretched until a tension corresponding to the resistance is generated, the disks 6 and 7 rotate at the same speed and with a constant phase difference (spring 8 When the elongation is 0, the phase difference is 0). Since the resistance received by the agitator 5 changes depending on the amount of toner 1 in the hopper 2, the elongation of the spring 8,
, 70 phase difference allows the remaining amount of toner in the hopper to be detected.

To illustrate the means for detecting the phase difference between the discs 6 and 7, as shown in FIG. .1
The phase difference can be detected by pasting 4 and sensing this with the photosensor 15 and detecting the time from when the mark 14 on the disk 7 passes until when the mark 13 on the disk O passes. Further, as shown in FIG. 7, one disc 7 is provided with an optical mark 16 indicating a specific position, and the other disc is provided with a wedge-shaped optical mark 17 whose width changes depending on the rotational position of the disc 7. It is also possible to detect the phase difference from the width of the optical mark 170 at the time when the optical mark 16 is sensed.

In addition to the method of optically detecting the phase difference between the two discs 6 and 7, the agitator resistance and
As a result, the remaining amount of toner can be detected.

As described above, due to the remaining toner 1 in the hopper 2,
Fluctuations in the amount of replenishment of the replenishment roller can be corrected by adjusting the amount of remaining toner explained with reference to FIG. For this purpose, in this embodiment, in addition to manually inputting a number of copies and a paper size detection signal to the central processing unit CPU, which performs quick disconnection control of the clutch CL, as shown in FIG.
The detected amount of phase difference between the side disks 6 and 70 by 8 is also input.

Since this device is configured as described above, the number of copies and paper size are manually entered and stored in the CPU, the amount of toner to be replenished is calculated from these, and when the cumulative total reaches a predetermined value, the hopper 2 Clutch CL is engaged to replenish toner 1, and replenishment roller 5a rotates. At the same time, the agitator 5 also rotates, and the detected amount of the rotational phase difference generated between the two rotating plates 6 and 7 due to the resistance of the toner is inputted from the phase detector 18 to the CJU. This allows the CPU
, the number of rotations of the replenishment roller 25 corresponding to the amount of toner calculated from the number of copies and paper size is corrected for fluctuations in the amount of replenishment of the replenishment roller due to changes in the amount of toner remaining in the hopper, and the number of rotations is adjusted to the corrected number of rotations. Clutch CL is energized for a corresponding period of time. In this way, regardless of the amount of toner remaining in the hopper, the developing device is supplied with an appropriate amount of toner corresponding to the number of copies and paper size.

The remaining amount of toner in the hopper 2, which is calculated by the CPU by manually adjusting the phase difference between the rotations of the two disks 6 and 70, is output from the CPU to a display placed in a place that is easily visible to the operator to display or warn the operator. This allows the operator to properly prepare the toner to be replenished. In addition, if the number of copies that can be made is displayed based on the amount of toner remaining as described above, the machine may stop during copying a large number of copies, the developer density may drop significantly due to copying after reaching the end, or the carrier may run out. Problems such as abnormal images caused by adhesion to the photoconductor or copy paper can also be prevented.

Furthermore, if the number of copies specified is greater than the number of copies that can be made due to the remaining amount of toner in the hopper, a warning will be issued with a lamp or sound, which will further ensure the prevention of the above problems. It can be done.

As described above, according to the present invention, the structure is simple, does not cause an increase in price, and can easily prevent fluctuations in the replenishment amount of the replenishment roller in response to changes in the amount of residual toner in the hopper in a constant replenishment type toner replenishment device. Since it is automatically corrected and the toner concentration of the developer can always be maintained at a constant appropriate value, a remarkable effect can be obtained in improving copy quality and preventing the occurrence of abnormal images.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of a conventional fixed-quantity replenishment type toner replenishment device, and FIG. 2 is a curve diagram showing changes in replenishment acid per revolution of the replenishment roller with respect to the amount of toner remaining in the hopper.
3 is a sectional view of a part of the hopper according to the embodiment of the present invention, FIG. 4 is a perspective view of the agitator portion thereof, FIG. 5 is a schematic diagram showing the overall configuration including the control circuit of the present invention, and FIG. FIG. 7 is a schematic diagram showing an example of means for detecting the rotational phase difference between two discs for detecting the toner agitation state by the agitator of the above embodiment. 1... Toner 2... Toner replenishment hopper 3... Replenishment roller 4... Azidata shaft 5...
Agitator 6, 7, 8, 18...Agitation state detection means CPU...
Central processing unit (toner supply amount correction means) Fig. 5 Fig. 6 Factor 7

Claims (1)

[Claims] (1)) It has a hopper for replenishing Qi and a replenishment roller provided at the lower end discharge port of the hopper, and the rotation of the replenishment roller transfers toner consumed during copying to the developing device. In the toner replenishing device for an electrophotographic copying machine, the toner replenishing device includes: an agitator for agitating the toner in the hopper; a means for detecting a change in the agitation state of the agitator according to a remaining amount of toner in the hopper; A toner replenishing device comprising: means for correcting fluctuations in the toner replenishment amount of the replenishment roller due to changes in the remaining amount of toner in the hopper, based on an amount detected by the means. (2) The toner replenishing device according to claim 1, wherein the amount of toner remaining in the hopper is displayed or warned based on the amount detected by the agitation state detection means of the agitator. (6) The toner replenishing device according to claim 1 or 2, wherein the number of copies that can be made is displayed based on the amount of toner remaining in the hopper based on the detected amount. (4) Claims 1 to 4 are characterized in that a means is provided to issue a warning when the detected amount specifies a number of copies that is greater than the number of copies that can be made based on the amount of toner remaining in the hopper. The toner replenishing device according to any one of Item 3.