JPS5986067A - Electrophotographic recording device - Google Patents

Abstract

PURPOSE:To make the amount of electrostatic charge of a photosensitive body against temperature fluctuations by controlling the amount of electrostatic charge to photosensitive body according to its ambient temperature. CONSTITUTION:A thermistor 8 varies in resistance value with the detected ambient temperature of the photoreceptor formed of a body 10 to be charged, a counter electrode 11, etc. The voltage of the control grating electrode 4 of a corona discharger varies with the resistance value to control the amount of electrostatic charge to the photosensitive body by corona discharge, and consequently the amount of electrostatic charge of the photosensitive body is made constant against temperature fluctuations. Therefore, a picture of good quality having constant density, etc., is obtained irrelatively to temperature without any following process adjustment, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic recording apparatus, and particularly to controlling the amount of charge charged to a photoreceptor.

In the electrophotographic method, the photoreceptor is generally charged with a stain charge uniformly by a discharge wire of a corona discharge device and then exposed to light.The electrophotographic method is developed by charging the photoreceptor to the same polarity as the photoreceptor, taking advantage of the fact that the amount of charge in the exposed area decreases. In this method, a recorded image is obtained through the process of placing a developer or an oppositely charged developer on a photoreceptor, transferring it onto the entire sheet of paper, and fixing it. However, the amount of charge charged on the photoreceptor, which plays an important role in this more advanced electrophotographic method, changes depending on changes in temperature. Therefore, the discharge current must also be varied to maintain a constant amount of charge. Furthermore, the amount of charge on the photoreceptor affects all steps of the amount of charge, and in order to obtain uniform image quality on the recording surface, it is necessary to change the conditions of subsequent processes. In this way, changes in temperature promote changes in the amount of charge on the photoreceptor, which affects the recording surface, such as shading and fogging.

Therefore, an object of the present invention is to provide a recording apparatus that takes the above-mentioned drawbacks into consideration and can obtain a uniform charge amount without changing the band %in on the photoreceptor even when the temperature changes.

According to the invention, an electrophotographic recording apparatus includes means for measuring the temperature near a photoreceptor made of a photoconductive material, means for charging the photoreceptor, and charging the photoreceptor according to the measured temperature near the photoreceptor. An electrophotographic recording device including means for changing the amount of charged electric charge is obtained.

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the change in drum current required to bring a general 8e-As type photosensitive drum to a certain charging potential Xv with respect to temperature. As shown in the figure, it can be seen that as the temperature rises, the current flowing into the photoreceptor increases.

Figure 2 is a diagram of an embodiment of the non-invention, which is illustrated by Yu Banta, a dentist, and includes a corona discharge electrode wire 1, a shielding frame 2, a DC power source 3, 5, a control grid electrode 4, a thermistor 8, and a thermistor. Correction resistance 7,
9, a resistor 6, a charged portion 10, and an electrode 11.

The charged portion 1o is not a photoconductor, but is integrated with the electrode 11 to form the entire photoreceptor. The electrode 11 is a counter electrode to the corona discharge electrode 1, and the thermistor 8 is placed near the photoreceptor.

Now, when the photoreceptor temperature is az (°0) in FIG. 1, a certain voltage Yv is applied from the DC power supply 3 to the corona discharge electrode wire 1. As a result, a corona discharge occurs between the photoreceptor and the stain electrode 11, and a discharge current b2 (μA) flows into the electrode 11 of the photoreceptor, and the charged portion 10 of the photoreceptor is charged to a charging potential Xv. Here, the amount of charge on the photoreceptor is the control grid electrode 4
limited by the voltage applied to the A voltage obtained by dividing the voltage of the DC power source 5 by a resistor 6, a thermistor 8, and thermistor correction resistors 7 and 9 is applied to the control grid electrode 4, and this voltage is the same as the voltage applied to the corona discharge electrode wire 1. It is polar. When the temperature near the photoreceptor decreases due to changes in the environmental temperature and reaches the values a and CC shown in FIG. The series resistor 6 increases the potential applied to the control grid electrode 4.

The charge from the corona discharge electrode 1 is limited by the increased potential, and a discharge current b1 (μA) shown in FIG. 1 necessary to bring the charging potential on the photoreceptor to Xv flows to the electrode 11. When the photoreceptor temperature further increases to a3CC) shown in FIG. 1, the resistance of the thermistor 8 decreases, and the thermistor 8,
The axial pressure resistors 7, 9 and the series resistor 6 reduce the voltage applied to the control grid electrode 4, thereby increasing the charge from the corona discharge electrode 1 and increasing the voltage required to reach the charging potential Xv on the photoreceptor. A discharge current b3 (μA) shown in FIG. 1 flows through the counter electrode 11. As shown in FIG.
A), a2 ('C), the discharge current b2 (μA)
+''a ('O) By controlling the current to be an emission current b3 (μA), the photoreceptor can be charged to a constant potential Xv regardless of temperature changes.

As explained above, by detecting the temperature near the photosensitive area and controlling the amount of charge, the entire photoreceptor can be charged at a constant potential despite multiple temperature changes, so the conditions of the process after charging can be changed. This eliminates the need for a good electrophotographic recording image.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between the temperature change of the photoreceptor and the discharge current required to keep the photoreceptor at a certain level, and FIG. 2 is a block diagram showing an embodiment of the present invention. 1...Discharge electrode wire, 4...Control grid electrode, 8...Thermistor, 10...Charged object, 11...Counter electrode M

Claims (1)

[Claims] In an electrophotographic recording apparatus, there is provided a means for measuring the temperature near a photoreceptor made of a photoconductive material, a means for charging the photoreceptor, and an amount of charge charged to the photoreceptor according to the measured temperature near the photoreceptor. and means for changing the electrophotographic recording device.