JPS63180986A - Toner supply circuit - Google Patents

Abstract

PURPOSE:To prevent developer concentration and print density from decreasing by providing a concentration control part which inputs even a photosensitive drum rotation signal. CONSTITUTION:The concentration control part 1 inputs a printing period signal indicating that a photosensitive drum 4 is in process of exposure and a printing quantity signal which is the integral value of the number of print dots on a form and rotates a toner motor 2 for a time proportional to the value of the printing quantity signal to supply toner to a development part 3. Further, the photosensitive drum rotation signal indicating that the photosensitive drum 4 is in rotation is inputted and a toner motor 2 is driven for a constant period at constant intervals of time when the photosensitive drum 4 is in rotation and not in a printing period to supply the toner to a development part 3, thereby correcting a scatter amount by the rotation of the photosensitive drum 4. Consequently, a decrease in developing device concentration and a decrease in printing density when intermittent printing operation is performed frequently are precluded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic printing device, and particularly to a toner supply circuit for a device using a two-component development method.

[Conventional technology]

Conventionally, this type of toner supply circuit, as shown in FIG. 3, includes a density control unit 1 which uses a print period signal and a print amount signal by two people, a toner motor 2 which receives the output of the density control circuit as input,
It had a developing section 3 and a photosensitive drum 4 which received the output of the toner motor 2 as input.

Next, the operation will be explained using FIG. 4.

The density control unit 1 inputs a print period signal indicating that the photosensitive drum is being exposed to light and a print amount signal that is an integrated value of the number of printed dots on the paper, and controls the toner for a time proportional to the value of the print amount signal. The motor 2 is rotated to supply toner to the developing section 3.

The developing section 3 prints on the photosensitive drum 4 using a two-component development method including toner and carrier, and at this time an amount of toner proportional to the number of printed dots is consumed.

[Problem that the invention seeks to solve]

The above-mentioned conventional toner supply circuit replenishes the consumed toner in proportion to the printing amount, and does not take into account the amount of toner that is brought onto the photosensitive drum 4 at times other than the printing period, as shown in FIG. As shown in , when printing is performed intermittently and the photosensitive drum 4 is rotating between each printing period, the amount of toner brought to the photosensitive drum 4 is large, so that the amount of toner gradually increases. There was a drawback that the density in the developing device was lowered, and the density of the print on the paper was also lowered.

[Means for solving problems]

The toner supply circuit of the present invention has a density control section 1 that also receives a photosensitive drum rotation signal as an input, unlike the conventional technology.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention.

A density control section 5 which receives a photosensitive drum rotation signal, a printing period signal and a printing amount signal as three inputs, a toner motor 2 which receives the output thereof as an input, a developing section 3 which receives an output of the toner motor 2 as an input, and a photosensitive drum 4. have.

Next, the operation will be explained using FIG. 2.

The density control unit 1 inputs a printing period signal indicating that the photosensitive drum 4 is being exposed to light and a printing amount signal which is an integrated value of the number of printed dots on the paper, and outputs a signal proportional to the value of the printing amount signal. The toner motor 2 is rotated for an amount of time to supply toner to the developing section 3.

In addition, a photosensitive drum rotation signal indicating that the photosensitive drum 4 is rotating is input, and even when the photosensitive drum 4 is rotating and it is not a printing period, the toner motor 2 is driven for a fixed period at fixed time intervals to perform development. The photosensitive drum 4 is supplied with toner to the photosensitive drum 4.
Correct the amount carried by 0 rotation.

〔Effect of the invention〕

As explained above, the present invention corrects the amount of toner used when the photosensitive drum 4 is rotating and is not in the printing period, thereby preventing a decrease in developer density and a decrease in print density when there are many intermittent printing operations. There are certain effects that can be achieved.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a timing diagram of an embodiment of the invention, Fig. 3 is a block diagram showing a conventional example, and Fig. 4 is a timing diagram of the conventional example. be. 1... Concentration control section of conventional technology, 2...
Toner motor, 3...Developing section, 4...
Photosensitive drum, 5... Density control section of the present invention.

Claims (1)

[Claims] a density control circuit having three inputs: a signal indicating that the photosensitive drum is rotating; a signal indicating that it is a period for printing on the photosensitive drum; and a signal indicating the value of the print amount; and a toner supply motor having the output thereof as input; A toner supply circuit that includes a developing section that receives the output of a toner supply motor as an input, and a photosensitive drum.