JPS5822183Y2 - Developer application amount control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developer coating device for coating a photosensitive member in a wet-type electronic copying machine.

Conventionally, as shown in Japanese Unexamined Patent Publication No. 52-105836, it is possible to detect in advance whether a document is a solid image, a halftone image, or a line image.
It is known that adjusting the amount of developer on the photoreceptor before transfer is effective when the original is uniformly solid or lined, but it is effective when the original contains solid areas or lines. If the removal ability is adjusted to the line portion, the image in the solid portion becomes blurred, and if the removal ability is adjusted to the solid portion, the amount of developer transferred to the transfer material increases.

The present invention directly detects and corrects the amount of developer after development on the photoreceptor, thereby eliminating the drawbacks of the conventional method.

FIG. 1 is a schematic front view of the entire wet-type electronic copying machine according to the present invention, in which a photoreceptor belt 1 having a photoconductive layer on its surface is charged with a charger 2, and a base plate 3 is moved. The optical system 4 exposes the photoreceptor belt 1, the developer in the developer storage tank 5 is supplied to the developer container 7 by the pump 6, and the roller 8 applies the developer to the photoreceptor belt 1 to perform development. After development, the developer is blown off by the wind pressure of an air knife 9 to a predetermined thickness.

10 is a rotating body with synthetic paper on its surface. A transfer sheet 11 made of mylar, electrostatic recording material, etc. is wound.

The transfer sheet 11 is charged by a preliminary charger 12, and then an insulating liquid is supplied from an insulating liquid storage tank 13 such as an isopar to a briwetter 15 by a pump 14 to form an insulating liquid film on the charged transfer sheet 11. The toner image 16 on the developed photoreceptor belt 1 is closely attached to the toner image 16.

The toner electrophores within the insulating liquid film, is attracted to the transfer sheet 11, and is transferred.

The transferred transfer sheet 11 is separated from the photoreceptor belt 1 by corona discharge from the separation corona discharger 17, and then transferred to the dryer 1.
It is dried at 8.

When the transfer is completed, the transfer sheet 11 is removed from the rotating body 10 and transported to a predetermined position.

19 is a cleaning device.

Such a wet-type electronic copying machine is well known, and the present invention is to provide an automatic developer application amount control device A downstream of the air knife 9 in such an apparatus.

One embodiment will be described with reference to FIG. 1 is a photoreceptor belt, 9 is an air knife, and a light source 20 that illuminates the surface of the photoreceptor belt 1 and a photosensor 21 that receives the reflected light are provided on the downstream side of the air knife 9, and the detected current is detected by a comparison amplifier. 22 performs comparison and amplification with the reference current to control the voltage control section 23, an air volume regulator 25 is provided in the supply path from the blower 24 to the air knife 9, and the voltage control section 23
The air volume regulator 25 is automatically controlled based on the output voltage.

That is, due to the wind pressure of the air knife 9, the developer on the photoreceptor belt 1 after development has a thickness close to a predetermined thickness, and this thickness is detected by the photosensor 21.

When the detected thickness is thinner than a predetermined value, the air flow regulator 25 is automatically controlled to be weakened, and when it is thicker than a predetermined value, it is strengthened, so that the thickness of the developer after development on the downstream side of the air knife 9 is always kept constant. It is supposed to be done.

A photoreceptor drum may be used instead of the photoreceptor belt.

According to the present invention, the reflected light from the photoreceptor is detected downstream of the air knife, and the air volume of the air knife is automatically controlled based on the detected value, so changes in the environment (temperature and humidity) when the copying machine is used
Even if the viscosity of the developer and the evaporability of the developer change due to changes in the environment inside the copying machine due to running, the thickness of the developer after development on the photoconductor downstream of the air knife can be kept constant, and the developer during transfer can be kept constant. The transfer performance of the toner electrophoresed therein and transferred to the transfer sheet can be maintained constant, and accurate transfer can be performed.

[Brief explanation of drawings]

FIG. 1 is a schematic front view of the entire wet-type electronic copying machine to which the present invention is applied, and FIG. 2 is a front view of an embodiment of the present invention. 1... Photoreceptor belt, 9... Air knife, 20... Light source, 21... Photo sensor, 24... Blower 25... ...Air volume adjustment device.

Claims (1)

[Scope of utility model registration request] In a wet-type electronic copying machine in which a photoreceptor having a photoconductive layer on its surface is charged and exposed, a toner image is formed with a developer, and the toner image is closely transferred to a transfer sheet, the developer is used after development. A developing solution application amount control device that includes a photoconductor surface reflectance detection device provided downstream of an air knife for adjusting the amount, and an air volume regulator that can control the air volume of the air knife based on the detected value.