JPS5965832A - Control device of image recording - Google Patents

Abstract

PURPOSE:To obtain a recording image having always excellent image quality by standardizing the exposing condition for the purpose of exposing the original image, detecting the density of the original image after the standardization and correcting the exposing conditions according to the detected value. CONSTITUTION:A control device for image recording is designed to supply the electric power set by a control means 8 for the quantity of light to a light source 2 for exposing so that the light source emits light in the case of measuring the density of an original. The exposure of the light source 2 is changed by a control circuit 8 for exposure and when the surface potential of a photosensitive drum 3 attains a standard potential, an original 10 is preliminarily exposed by the quantity of the exposing light determined just before the same and the density thereof is measured. The quantity of the preliminary exposing light is corrected in accordance with the result obtd. by said measurement. The recording image having always high image quality is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an automatic exposure (VTAE) method in which preliminary irradiation is performed to determine the density of a recording medium in advance to determine the optimum exposure amount, and then recording is performed on the recording medium. The present invention relates to an image recording apparatus, and in particular to an image recording control apparatus that allows a recorded image of the same density to be always obtained for a recording medium of the same density.

In conventional recording devices of this type, the density of the document or recording medium is measured by irradiating it with a predetermined constant exposure amount, but even if the density of the document is the same, If the sensor is replaced or there is a change in environmental conditions such as temperature, the measured density value will change, resulting in an error in the optimal exposure amount, and exposure using a light amount that includes this error will result in a change in the measured density value. Because of this, there is a drawback that so-called fogging occurs in the recorded image and the density of the entire recorded image jumps toward white, resulting in a deterioration in reproduced image quality.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image recording control device that eliminates the above-mentioned conventional drawbacks and can always obtain recorded images of the same density for recording objects of the same density.

The following is a detailed description of the invention with reference to the drawings.

An example of the configuration of the essential parts of the image recording control apparatus of the present invention is shown in FIG. 1, and an example of the process of controlling the amount of light from the exposure light source is shown in FIG.

In the configuration example shown in the first figure, a reference density plate representing the density of the /1f-1 standard, A a light source for exposure, 3 a photosensitive drum, G a potential measuring means or sensor for measuring the surface potential of the photosensitive drum 30; On the left is analog-digital (8-D
) converter, B is a microcomputer that performs arithmetic processing such as calculation, storage, and communication, 7 is a digital-to-analog (D-A) converter, and g is an exposure amount control circuit that controls the amount of light from the light source. When measuring the original density, the exposure light source is supplied with electric power set by the light amount control means K to cause it to emit light.

The output light from the exposure light source is reflected by a reference density plate and then sent to a conventional optical system such as a mirror or lens (not shown).
to form a latent image on the surface of the photosensitive drum 30. The latent image on the photosensitive drum 3 moves as the drum rotates 30 times, and when it reaches the position of the sensor, the potential of the latent image is measured by a sensor tag.The potential of the measurement result is transferred to an A-D converter. S converts the analog value into a digital value and sequentially transfers it to the microcomputer (CPU) b.

The cono microcomputer B performs arithmetic processing on the received latent image potential data according to the flowchart shown in the second figure. That is, first, in step S, it is determined whether or not the surface potential of the photosensitive drum 30 is at a predetermined reference potential, and if it is not at the reference potential, step S8 is performed.
．． In step S2, it is determined whether or not it is necessary to increase the light amount of the exposure light source 2, and if it is necessary to increase the light amount, a command to increase the light amount is issued in step S3 via the I)-A converter r. 1c if it is supplied to the exposure control circuit g and an increase in the light amount is not required? d.In step sp, the command to decrease the light amount is given to D.
- It is also supplied to the exposure amount control circuit g via the A converter g. When it is determined in step S/ that the exposure amount of the light source λ has been changed by the exposure amount control circuit g according to this instruction and the surface potential of the photosensitive drum 30 has reached the reference potential, the process moves to step S5, and the step S5 is determined immediately before that. Depending on the amount of lightning,
The document 10 is subjected to preliminary exposure and its density is measured, and according to the measurement result, the light amount of the preliminary exposure by the light source is corrected in step S6, and then, in step S7, the data of the corrected light amount is stored in D- Exposure conditions that automatically provide the best image quality by supplying a voltage from the exposure control circuit 8 to the light source that provides the optimum exposure for the document 10 at that time by transferring it to the A converter 7. Make the necessary records under the

In the above description, the density of the recorded image is adjusted by controlling the amount of light from the exposure light source, but it is also possible to control the bias potential applied to the surface of the photosensitive drum 30.

As is clear from the above description, according to the present invention, even if the sensitivity of the photosensitive drum in an electrostatic latent image recording device changes due to changes in environmental conditions such as replacement or temperature, it is possible to Since recording can be carried out while maintaining a recorded image of the same density, a special effect can be obtained in that a recorded image of excellent quality can always be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of the configuration of essential parts of the image recording control apparatus of the present invention, and FIG. 2 is a flowchart showing an example of the recording density control process in the same example. /...Reference density plate, C...Light source for exposure, 3
...Photosensitive drum, G...sensor, S...
A-D converter, 6...microcomputer, 7...I) -A converter, za...exposure! jt control circuit, 10...manuscript. Patent applicant Canon Co., Ltd.

Claims (1)

[Claims] An image recording control device characterized in that the exposure conditions for exposing an original image are standardized, the density of the standardized original image is detected, and the exposure conditions are corrected according to the detected value.