JPS62499B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image quality control device for an electrophotographic copying machine.

Electrophotographic copying machines have become increasingly sophisticated in recent years, but in order to achieve even higher fidelity (image quality reproducibility, colorization, etc.), higher speeds, and longer lifespan (maintenance intervals, image quality maintenance, etc.), so-called photoreceptor Fatigue (increase in residual potential, decrease in charging potential) is a major problem, and effective means to solve this problem include program control of image quality and multi-segmentation of the photoreceptor. The former aims to correct the image quality according to the usage status of the photoreceptor, thereby achieving the above-mentioned high fidelity and long life, while the latter uses multiple segments of the photoreceptor sequentially to improve the usage of each segment. The aim is to reduce the time interval and frequency of use, thereby achieving the above-mentioned high speed and long life.

However, since the manner in which a photoreceptor fatigues depends on its usage conditions, conventionally proposed method If a single program control was used to handle all photoreceptors at once, the density and other image quality would vary significantly from segment to segment, or the number of copies would need to be set too low. There were various drawbacks such as being uneconomical and uneconomical.

The present invention eliminates the above-mentioned conventional drawbacks, and provides an image quality control device for an electrophotographic copying machine that can independently detect photoreceptor fatigue for each segment and perform image quality correction for each segment. This is the purpose.

The present invention will be described with reference to embodiments shown in the drawings.

In FIG. 1, 1 is a copying section of an electrophotographic copying machine, 2 is a control section thereof, 3, 3', and 3'' are photoconductor segments each having both side edges of a sheet-like photoconductor attached to an endless belt 4; A driving roller for the endless belt 4, a detector 6, a controller 7, and an image quality corrector 8.The detector 6 detects the degree of fatigue of the photoreceptor segment (3 in FIG. 1) at the detection position. The detected value is transmitted to the controller 7. The controller 7 receives a signal input in conjunction with the drive roller 5, and transmits the detected value transmitted from the detector 6 at that time to which photoreceptor segment. It compares the identified detection value with a preset reference value to derive the deviation between the two, and transmits a control command corresponding to either of the two to the image quality corrector 8. Reference values can be set individually for each photoreceptor segment, and it is equipped with a memory function that stores input information from the time a detected value is input until the time when the corresponding control command should be output.Image quality correction The unit 8 receives control commands from the controller 7 and corrects the amount of charge, the amount of exposure, the developing bias voltage, etc. of the copying section 1 in accordance with the control commands.

When the photoconductor segment 3 comes to the detection position, its degree of fatigue is detected by the detector 6, and the detected value is compared with a preset reference value corresponding to the photoconductor segment 3 to derive a control amount. When the segment 3 comes to the photosensitive position, the image quality corrector 8 is operated according to a control command to correct the amount of charge, the amount of exposure, the developing bias voltage, etc., thereby correcting the image quality of the photoreceptor segment 3. The same applies to the other photoreceptor segments 3', 3''.

In addition to the one shown in Figure 1, examples of multiple segmentation of the photoreceptor include an endless belt-shaped one, a web-shaped one b, a folded web c, and a drum-shaped one, as shown in Figure 2. thing d,
The amount detected by the detector 6 includes the size of the exposure amount, the density, the number of sheets, the potential on the photoreceptor (contrast), the image density (contrast), and the afterimage density of cleaning. , temperature and humidity of the photoreceptor, environmental temperature and humidity, copy mode (one-to-one or multi-copy), and the amount of correction by the image quality corrector 8, in addition to the above, for example, toner density. Furthermore, in the case of a color copying machine where the usage of each segment is predetermined, it is possible to use an inexpensive dedicated device with a prefixed control program. It is also possible to create an image pattern suitable for measuring the intensity, measure its potential, density, contrast, etc., and correct the measured values by feeding back, thereby achieving high-level control.

As described above, in an electrophotographic copying machine, the degree of fatigue of a plurality of photoreceptor segments is individually detected by a detector for each segment, and an independent control program is used for each segment according to the detected value. Since the charge amount, exposure amount, developing bias voltage, etc. are corrected via the controller and image quality corrector, even if the sensitivity of each segment varies or the usage conditions of each segment are significantly different, However, each segment can be used under the optimum conditions, and there is no variation in density or other image quality for each segment, and there is no need to leave an undue margin in the number of copies, thereby ensuring uniform copy quality. In addition, it is possible to reduce costs by managing the lifespan of each segment, and is particularly suitable when each segment is used exclusively for each color separated in a color copying machine. It has excellent effects.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing an embodiment of the present invention;
The figure is a schematic diagram showing an example of multiple segmentation of a photoreceptor. 3, 3', 3''...photoreceptor segment, 6...detector, 7...controller, 8...image quality corrector.

Claims (1)

[Claims] 1. In an electrophotographic copying machine consisting of a copying section and a control section, the amount of charge, amount of exposure, developing bias voltage, etc. are controlled programmatically according to the degree of use of the photoreceptor.
A driving member installed in the copying unit to sequentially move the plurality of photoreceptor segments and output a movement signal; and a driving member installed opposite to the moving photoreceptor segments and detecting the degree of fatigue of the photoreceptor segments. A detector outputting the detected value, a movement signal from the driving member, and the detected value from the detector are inputted to identify which photoreceptor segment the detected value from the detector belongs to. and a controller that compares this detection signal with a preset reference value and outputs a command signal according to the difference, and inputs the command signal from this controller to determine the amount of charge related to the photoreceptor segment. An image quality control device comprising: an image quality corrector that outputs an image quality correction amount such as an exposure amount or a phenomenon bias voltage to a copying section.