JPH04348370A - Automatic toner supply device - Google Patents

Abstract

PURPOSE:To uniformly keep printing density on a paper. CONSTITUTION:This device is constituted of a toner hopper 12 consisting of a motor 13 for supplying toner and a screw 14, and a developing device 4 for attaching the toner to the surface of an OPC drum 1 around which an electrostatic charging part 2, an exposing part 3, the developing device 4, a transfer part 5, a cleaner part 6, and an erasing part 7 are arranged, a line sensor 9 for observing the black solid density of the whole in a width direction on the printed paper 11, and a control part 10 for driving the motor 13 of the toner hopper 12 to rotate the screw 14 according to a signal from the line sensor 9, and the black solid density of the whole of the printed paper 11 is measured by the line sensor 9. Based on the variation of the density, the correct amount of toner is supplied from the toner hopper 12 to the developing device 4. Then, a toner image is transferred on the paper 11 by making the paper 11 pass through the transfer part 5, transferring the toner image to the paper 11 from the OPC drum 1 and fixing it there by a fixing part 8.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to electrophotographic apparatus such as copying machines and printers, and more particularly to an automatic toner supply mechanism.

0002

2. Description of the Related Art A conventional automatic toner supply device has a toner hopper consisting of a motor and a screw for supplying toner, and a density sensor for checking the density on a toner mark printed in solid black. The toner hopper motor is driven by the signal from the toner hopper, and the screw is rotated to supply toner from the toner hopper to the developing device.

0003

[Problems to be Solved by the Invention] In the above-mentioned conventional toner automatic supply device, the toner hopper motor is driven by looking at the density on the toner mark printed in solid black on a portion of the edge of the paper, and the screw is rotated. However, since the toner is supplied to the developing device, there is a drawback that if there is uneven density on the printed paper, an accurate amount of toner cannot be supplied from the toner hopper to the developing device.

An object of the present invention is to measure the black solid density of the entire printed paper using a line sensor, and supply an accurate amount of toner from a toner hopper to a developing device according to the amount of change in the density. An object of the present invention is to provide an automatic toner supply device that can eliminate the drawbacks of the above and maintain uniform printing density on paper.

[0005]

[Means for Solving the Problems] The toner automatic supply device of the present invention includes a toner hopper consisting of a motor and a screw for supplying toner, and a line for checking the black solid density in the entire width direction on printed paper. The toner hopper motor is driven by a signal from the line sensor, and the screw is rotated to supply toner from the toner hopper to the developing device.

[0006]

Embodiments Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of an automatic toner supply device according to an embodiment of the present invention.

In FIG. 1, the automatic toner supply device of this embodiment includes an organic photoconductor around which a charging section 2, an exposure section 3, a developing body 4, a transfer section 5, a cleaner section 6, and an erase section 7 are arranged. Drum (Organic Photo Co.
(hereinafter abbreviated as OPC drum) 1, a fixing section 8, a line sensor 9, a control section 10, and a paper 11
, toner hopper 12, motor 13, and screw 1
It is composed of 4.

[0009] By passing the paper 11 through the transfer section 5,
The toner image is transferred by the OPC drum 1 and fixed by the fixing section 8. Then, the line sensor 9 measures the overall black solid print density change in the width direction of the paper 11, the signal is processed by the control unit 10, and the toner hopper is adjusted according to the amount of black solid print density change in the entire width direction of the paper 11. The motor 13 in the developer 12 is driven, the screw 14 is rotated, and the toner is supplied to the developer 4.

[0010] Here, the transfer of the toner image onto the paper 11 is as follows:
The electrophotographic process is performed in the transfer section 5, and the charging section 2,
A toner image is formed on the OPC drum 1 after passing through an exposure section 3 and a developing device 4, and is transferred onto a sheet of paper 11 at a transfer section 5.

Unnecessary toner remaining on the OPC drum 1 is removed by the cleaner section 6, and the unnecessary toner remaining on the OPC drum 1 is removed by the erase section 7.
Then, unnecessary static charges on the OPC drum 1 are erased, and the cycle of the electrophotographic process is repeated again.

0012

As explained above, the automatic toner supply device of the present invention measures the black solid density of the entire printed paper using a line sensor, and dispenses an accurate amount of toner according to the amount of change in density. By supplying the toner from the toner hopper to the developing device, it is possible to maintain uniform printing density on the paper.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an automatic toner supply device according to an embodiment of the present invention.

[Explanation of symbols]

1 OPC drum 2 Charged part 3 Exposure section 4 Developing device 5　　　　Transfer section 6 Cleaner section 7 Erase section 8 Fixing section 9 Line sensor 10 Control section 11 Paper 12 Toner hopper 13 Motor 14 Screw

Claims (1)

[Claims] 1. A toner hopper consisting of a motor and a screw for supplying toner, and a line sensor for checking the black solid density in the entire width direction on printed paper, and according to a signal from the line sensor, a toner hopper is provided. An automatic toner supply device, characterized in that the toner is supplied from the toner hopper to a developing device by driving a motor of the toner hopper and rotating a screw.