JPS58115453A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To control conditions of charging, exposure and development, and to obtain a good image quality, by exposing a monitor pattern, as well, by a laser beam for exposing a picture, detecting a toner image of its pattern by an image quality sensor, and grasping its density and width. CONSTITUTION:A monitor pattern 33 is formed on a drum side part 32 by reading out a pattern data stored in a read-only memory 12, synthesizing it with a recording image signal, modulating a laser 1, and exposing a photosensitive drum surface 3. A reflection factor of a toner image of a monitor pattern obtained by developing said pattern by a developing device 5 is detected by a sensor 60, and toner image density and toner image line width are grasped from strength of a detecting pulse and pulse width, respectively. This monitor pattern information, and information of the photosensitive surface potential from a potential sensor 61 are analyzed by a microcomputer 6, and the condition for forming an image is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention forms an electrostatic latent image on a photoconductor using a laser beam, and through the steps of developing, transferring, and fixing this electrostatic latent image, a recorded image is formed on paper. The present invention relates to an electrophotographic device that obtains great results.

The purpose of this invention is to provide an electrophotographic device that can always maintain the high quality of the image to be recorded, regardless of changes in the conditions such as changes in toner density or ambient temperature. FIG. 1 is a configuration explanatory diagram showing an example of a conventionally known droplet link. This device is
A laser beam with one conductor is horizontally scanned on the photosensitive drum 3 via the polygon mirror 2 to form an electrostatic latent image on the photosensitive drum 1. At the beginning of the company, charge 1 with charger 4 to a charge of 1 meter.
This is then irradiated with a laser beam modulated in accordance with the image information, resulting in exposure and an electrostatic field.

Thereafter, the electrostatic material obtained on the photosensitive drum 1 is developed with an AM device S, and then charged for transfer. The image is transferred to the paper 70 at step 44, and fixed at fixer 117 to obtain a recorded image on the paper. The ink on the photosensitive drum after transfer is cleaned by the cleaning device and charged again by the charger 4, and the nine operations described above are repeated. paper 7
The quality of *iii* obtained in 0 depends on the toner concentration, the amount of charge the toner has, the charged state of the photoreceptor due to the ambient temperature,
Or, the characteristics of the photoreceptor 041 may change depending on various conditions. Therefore, in the eleventh conventional apparatus, for example, a toner concentration detection means may be provided, and the amount of toner supplied may be controlled based on the output signal thereof.

However, currently proposed toner concentration detection means (1), for example those that detect the concentration from changes in coil inductance, have the following characteristics: (1) to safely and accurately detect the concentration; It was difficult to maintain the quality and density of the bronze statues at an appropriate level.

Here, the present invention has a simple structure, always clear,
The purpose of this device is to realize an electrophotographic device that can obtain high-quality images. Pattern 1. Nine points are detected by an image quality sensor installed close to the photoreceptor, and based on signals from the image quality sensor, control at least one of, for example, the radiant energy of the laser source, the toner concentration, and the charged potential of the photoreceptor. 〇Figure 2 is a block diagram showing an example of the apparatus according to the present invention. Here, an example is shown in which a drum-shaped object is used as the expanding/contracting light body and dry toner development is performed in the developing process. For the sake of it. In the figure, reference numeral 1 denotes a laser light source, and a signal that changes in accordance with image information is applied to a terminal 1G from a modulation circuit 11.

Reference numeral 2 denotes an optical scanning means for scanning the laser beam from the laser light source 1, and here an example using a polygon eraser is shown. A photosensitive drum is rotated at a constant speed in the direction of arrow a, and a laser beam disposed horizontally is guided by an optical scanning means 2 to the ζO photosensitive drum WE. A photosensitive drum is a photoconductive material that is wavelength-sensitive to selenium, magnetized cadmium, heptanide cadmium, and laser light source on a conductive stone substrate such as aluminum. It is composed of layers. 41a charger, which is installed close to the surface of the photosensitive drum ink.
Photosensitive drum S lI! For example, a positive charge can be uniformly stored on a surface.

s11 is located close to the photosensitive dot 5, and placed behind the exposure machine 1 and the 3J imager. -Ra 52, 4-253 for stirring the toner and carrier, and toner replenishing means 5 for controlling toner replenishment.
The numeral 60 is an image quality sensor which is a feature of the present invention, and is installed in the vicinity of the photosensitive drum IK at a position after the transfer process described below. Reference numeral 61 is a cabinet between the charger 1 and the exposure operator 1, and a surface potential needle installed close to the photosensitive drum 5 causes charging @41.
This is because the potential of each photosensitive drum 1 ol 1 image, which is uniformly charged, is detected. , 6 is a control circuit which receives signals s1 . The charger 41 is activated depending on the state of these signals.
Toner replenishment control means 54 in the developing device 5 controls the laser source 1 via the laser source drive circuit 15. This control circuit includes a D/D converter. Use 1. Note that in the present invention, the surface electrometer 61 is not necessarily required. 70 companies A sheet of paper fed out from a cassette 71 and brought into close contact with the surface of the photosensitive drum 1, 4
4 is a charger for transfer, 45 is a charger for separating the paper 70 from the photosensitive drum 3, and 46 is a charger for removing toner.The charger 44 for transfer is based on the polarity of the toner from the nature of the paper 70. Reference numeral 77 indicates a receiving section for the printed mourning paper, and 77 indicates a paper discharge tray for receiving the paper coming out from the fixing section 7. 8 is a cleaning device for cleaning the surface of the photosensitive drum ink after transfer, 45
is a charger, and this charge removes electricity from the photosensitive surface of the photosensitive drum 55, so that charging by the charger +14c is made more effective.

FIG. S shows an image quality sensor 60 used in the device shown in FIG.
0 - This is a configuration diagram showing an example. This image quality sensor from 60 companies has a light emitting section 601 and a light receiving section 602, and a large focus lens is installed so that the focal point is above the light emitting section and the light receiving section. 603, the photosensitive drum 1
I'm worried about this.

FIG. 4 is a perspective view showing an example of installing the image quality sensor 600.

On the photosensitive surface of the photosensitive drum 51, a range 832 is provided outside (at one end) of the range 31 where the recorded image is exposed to light, in which a monitor pattern 33 consisting of, for example, lines of various thicknesses or black areas is written. An image quality screen 60 is installed facing this range 32.

Then, it detects signals related to image quality Senna 60, Mineta pattern 330 line width, solid black area, and image quality. Read-only memory (ROM)
12 stores data corresponding to that pattern.
For example, the image is read out together with the recorded image and formed by exposing the photosensitive drum to red light. The monitor pattern 33 may be formed on the surface of the photosensitive drum every rotation of the photosensitive drum 5, or once every several rotations of the photosensitive drum 5.

With this configuration, the operation of the friend device is then controlled by the image quality sensor 60.
The operation of the monitor pattern 33 formed on the photosensitive drum 5 will be explained with reference to FIG. affected by conditions. The recorded image formed on the range 11i31 is exactly the same, and the monitor pattern 733 represents the formation pattern ll1t of this recorded image on the photosensitive drum 5.

The image quality sensor 60 having the configuration shown in FIG. 1 optically detects the formation of the monitor pattern 330. That is, the 1st v.
As shown in Afi) and ←), when the upper tube image quality sensor 60 passes the monitor pattern of width d, the image quality sensor 60
By firstly differentiating the output signal of the light-receiving layer sensor 602, the O control circuit 6 outputs a pulse signal p□+P2 t- at the part of the line, as shown in FIG. Input these pulse signals p□, P2, and the interval t t
rim and, for example, by performing the calculation shown in equation (1), the line @ntknowledgeOd-grudge・Δβ・t
(1) Direction: Correction coefficient ifL: Movement amount ti of the photosensitive drum S in unit time, image quality center t60 becomes 1 when the monitor passes through the large black part of the turn, and light is received from the image quality sensor 60. Cent
A signal P (corresponding to the amount of reflected light from the black area) is outputted, and the control circuit 6 measures the amplitude value M1 of the signal p3. ma
I know.

Side IIIIIIg] Road 4 is like this
Based on the signals related to the image IXK, these cnt
is set to a predetermined value.
control at least one of the following. That is, for example, if the line width is p thicker than a predetermined value and the density is thinner, the charging potential is increased and the amount of toner supplied is controlled to increase the line width and the density.
Control the speed so that it remains constant.

In addition, in the device shown in FIG. 2, the control circuit 6 is
In addition to the signal from the image quality sensor 60, the O signal e1t from the surface electrometer 61 is manually input, and in response to these signals, the charging potential of the charging @ 41, the radiant energy of the laser source 10, the amount of toner supplied, etc. The operations of charging by the charger 41, exposure by the laser beam, moderation by the developing unit 5, transfer to the paper 70 by the transfer charge @ 44, and fixing by the fixing unit 7 are conventional. This is done in a similar manner to known devices.

According to the nine devices configured in this way, the ambient temperature, humidity,
The various effects of changes in toner astringency are manifested as changes in the formation state of the moeta pattern that is finally formed on the photosensitive drum 5, and the image quality (line width, image density, etc.) of this monitor pattern #) is detected by an image quality sensor, and the charging by the charger, the irradiation energy key of the laser beam, and the toner control are controlled so that these values are at the optimum value.This makes it possible to always record high-quality images with a simple configuration. You will be able to get the benefit you deserve.

In the above embodiment, the laser beam from the laser source is horizontally scanned onto the photoreceptor for exposure, but it is possible to use a photoreceptor configured by arranging a plurality of light emitting elements such as #1 LICD in a horizontal line. For example, a light emitting element array or a light gate array may be used to perform image exposure. 19,
In ζζ, instead of the dry toner 1 used for image enhancement as the developing device, a concentrated acid toner developing device St may be used.

In this embodiment, the image quality sensor 60 used is an optical sensor having the configuration shown in FIG. It is also possible to detect the sharpness of the photoreceptor V. In 19, ζζ, it is better to form the monitor pattern SSt in the end area s2 of the photoreceptor, but the photoreceptor 5
In this case, the image quality sensor 6
0 is installed near the center of the photoreceptor where the O monitor pattern 33 is formed. Alternatively, the optimum control conditions may be determined by sequentially changing the normal monitoring pattern and repeating the checking and checking of the pattern several times.

As explained above, according to the present invention, with a simple configuration,
It is possible to realize an electrophotographic apparatus that can obtain a real recording me.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the configuration of an example of a conventional radar printer, Figure 2 is an explanatory diagram of the configuration of an example of a device according to the present invention; FIG. 4 is a structural perspective view showing an example of the senna; FIG. 5 is an explanatory view for explaining the operation of the senna; ...Phototactic food Tei, 3...
・Photoreceptor, 41... Charger, 5-・Developer, 6...
Control circuit, 60--Image quality sensor, 61--Surface potential needle, 70--Paper, 7--Fixing unit, 3s--Monitor pattern. Figure 3 Figure 4 Atsushi Figure 5 (A) (B) (C)

Claims (1)

[Claims] (1) The photoconductor is charged with an electric charge using a charging INK, and exposed to light from a light source to obtain an electrostatic latent image.This electrostatic latent image is then developed and transferred to paper. In the apparatus for obtaining an image, the photoreceptor is exposed to 1 light, 1
A 4JL pattern is formed through 1IJ6 processing steps, and a good signal related to the image quality of the formed 1st, 9th, 4JL, and A turns is detected by an image quality sensor installed close to the photoreceptor, and the An electrophotographic device that is characterized by controlling charging conditions, exposure conditions, and MS conditions based on an image quality sensor of 60*. (Inputting a series of signals directly to the line width of the turn and/or the image Il, and controlling at least one of the charging voltage of the charging IIO, the irradiation energy of the light II, and the toner supply amount of the developing device so that these become predetermined values. An electrophotographic apparatus according to claim 9, item 1, paragraph 1, characterized in that: