JPS5823034A - Electrophotographic method - Google Patents

Abstract

PURPOSE:To obtain copied images having invariably constant density by charging an electrophotographic photosensitive plate prior to the starting of electronic copying, and irradiating the photosensitive plate with specific infrared rays, only when a stop time, before the starting of copying, exceeds a prescribed time. CONSTITUTION:An erasing lamp 2, a charging corotron 3, a copying exposure system 4, and a preliminary fatigue lamp 5 are arranged around an electrophotographic photosensitive plate drum 1. The lamp 5 irradiates the charged surface of the photosensitive plate 1 with infrared rays which contain visible rays to give the charged potential preliminary fatigue, holding the potential on some conditions. Prior to the starting of copying, the photosensitive plate 1 is charged and a prescribed time when the potential is held constant through the irradiation of the lamp 5, is set. For successively copying, the lamp 5 is turned on only when a stop time exceeds the prescribed time. Thus, the potential is held constant to obtain copied images having constant density without refernce to the time length on the copying.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an electrophotographic method in which a large number of copies are continuously made through processes such as transfer and cleaning.

If the electrophotographic photosensitive sales company used in the electrophotographic method of Hi-seeds is used continuously and repeatedly, it will become fatigued and the charged potential will drop to a relatively low level. When the device is started to be used after a period of rest, for example, several seconds to several minutes, its initial charging potential temporarily becomes a relatively high level. An example of the change in the initial charging potential depending on the degree of fatigue of such an electrophotographic photosensitive plate is shown in No. 1 IIK of the attached drawing. In FIG. 1, the horizontal axis shows the number of consecutive uses of the electrophotographic photosensitive plate, that is, the number of times the electrophotographic photosensitive plate is used, and the vertical axis shows the electrophotographic IILO Teiden potential. After a relatively long rest period, the use of an electrophotographic photosensitive plate immediately starts continuous copying, showing changes in the charged potential of the nine-line crane. *This shows the condensation of the charging potential when the tC continuous value starts from zero. As is clear from such a curve, when continuous copying is performed after one electrophotographic photosensitive plate has been rested for a certain period of time, the original density of the first copy obtained and the density of the copied image obtained after the first few sheets are different. This undesirable tendency, which is undesirable because the image quality becomes different, also occurs due to an increase in the charging property of the electrophotographic photosensitive plate due to the dimming of the erase rung in a copying machine.

SUMMARY OF THE INVENTION An object of the present invention is to solve these conventional problems and provide an electrophotographic method that can always provide a constant density copy surface from the start of continuous copying.

According to the present invention, in an electrophotographic method in which copies are continuously made on an electronic photosensitive plate through processes such as charging, exposure, current generation, transfer, and cleaning, the electrophotographic photosensitive plate is The above-mentioned problems can be solved by charging the electrophotographic plate and irradiating the surface of the electrophotographic photosensitive plate with infrared rays including visible light only when the copying stop time before starting copying exceeds a predetermined time. Ru.

Next, the present invention will be described in more detail with regard to embodiments of the present invention based on FIGS. 1 to 6 of the accompanying drawings.

FIG. 1 schematically shows relevant parts of the structure of an electrophotographic photosensitive plate drum 10 for carrying out the electrophotographic method of the present invention. The electrophotographic photosensitive plate drum 1 rotates in the direction of arrow C, and is provided with an erase lamp 2, which is convex in the direction of rotation.
A charge corotron 8, a copy exposure system 1, and a pre-fatigue rung 5 are arranged in this order. The pre-fatigue lamp 5 used in the present invention is used to pre-fatigue the surface of the electrophotographic photosensitive plate drum 10 by irradiating it to reduce its charging property, and its spectral characteristics are as follows. As illustrated in Figure s@4c, it is preferable to use one that can emit infrared rays including visible light.

FIG. 3 shows the arrangement of the operations of each component when copying is performed using the apparatus configuration shown in FIG. As shown in FIG. 3, first, when the copying machine is operated to start copying, the drum 1 begins to rotate at times t and K, and the erase rung 2 is energized. The part of the drum 1 irradiated by the erase lamp 3 is charged; the time t when it reaches just below the drum 3;
Then, the charge corotron 3 is energized and charging starts.

[K,f'r- At time t! when the portion of the drum 10 charged by the dicoroto 4 reaches just below the front fatigue run 7''50, the front fatigue run fl is energized and the photosensitive plate surface The irradiation with infrared rays including visible light is carried out.The irradiation by the prefatigue run '71 is continued and stopped at the time t, when the drum 1 makes one revolution. No operation, no copying 0 A normal copy cycle starts at time t4 after the drum 1 has made one revolution.
Maybe it will start. That is, each time the photosensitive drum 1 starts copying, it undergoes energization of the erase run fs, charging by the charge corotron 3, and irradiation by the pre-fatigue lamp 5. During this period, no copying is performed, and the normal copy cycle is performed. After that you can start.

The relationship between the number of continuous copies and the charged potential of the photosensitive plate is illustrated in Fig. The -line A' shows the change in the charging potential when copying is started after a relatively long rest period, and corresponds to the curve ^ in Figure 1, but when compared with the curve ^. As can be seen, the increase in the initial charging potential is suppressed because of the charging by the charge corotron 8 and the pre-fatigue caused by the irradiation from the pre-fatigue lamp.

The nine curve B'd shows the change in the charging potential when copying starts after a relatively short rest period.It corresponds to the curve BK in Figure 1, but as can be seen by comparing it with curve 1. (1) Also, the increase in the initial charging potential is suppressed for the same reason.

As is clear from these curves in Figure 5, if the process described above is followed, the increase in the initial potential of the photosensitive material can be suppressed, so that a copying solution with a relatively constant density can be obtained from the start of copying. It will be done.

However, if the photosensitive plate has been subjected to many copy cycles and is sufficiently fatigued (exposed to electric charge and light 11), irradiation using the pre-fatigue rung 5 as described above will cause the opposite effect. As shown in the curve of figure M6, C-C-
The initial cycle potential drops too much, which is not good.
Therefore, in consideration of this point, the present invention calculates the time after the copying machine stops, and starts the next copy when the time after stopping exceeds the set time TR (several seconds to several minutes). The pre-fatigue run lamp f6 is turned on only when the copy is to be made, and the pre-fatigue lamp 5 is not turned on when the next copy is to be started within 701 hours.

According to the present invention, the increase in the initial potential of the photosensitive material is suppressed by doing this, and since it is not suppressed too much, it is always constant from the start of copying, no matter when copying starts. A copy of the concentration is obtained.

Furthermore, by combining the method of the present invention as described above and the growth control, if the process control determines that the concentration is low, the setting time TR for turning on or turning off the pre-fatigue lamp described above can be changed. If it is determined that the temperature is high, the temporary poor concentration can be corrected by shortening the set time TR or setting it to zero.

These controls can be performed on harmful birds by using a microphone.

[Brief explanation of the drawing]

Figure 1 of the accompanying drawings is a diagram illustrating the change in the charged potential of a photosensitive material after the start of copying in the conventional method, Figure 2 is a schematic diagram illustrating the electrophotographic method of the present invention, and Figure 3 is a diagram illustrating the electrophotographic method of the present invention. A diagram showing a tine in the photographic method, a diagram illustrating the characteristics of the pre-fatigue lamp used in the present invention, and a diagram S illustrating the change in the charging potential of the photosensitive material after the start of copying in the method of the present invention. 6A and 6B are diagrams illustrating changes in the charged potential of the photosensitive material after a pre-fatigue lamp is turned on for a highly fatigued photosensitive material and the copying of nine dots is started. 1... Electrophotographic photosensitive plate drum, 3... Erase lamp, 8... Charge coat tone, 4... Copy exposure system, 5... Pre-fatigue lamp. One continuous copy U3 number Figure 2 Figure 3 A (TLTrL)

Claims (1)

[Claims] In an electrophotographic method in which copies are continuously made on an electrophotographic photosensitive plate through processes such as charging, exposure, development, transfer, and printing, prior to the start of copying, electrophotographic exposure,
An electrophotographic method characterized in that the 111th surface of the electrophotographic photosensitive plate is irradiated with infrared rays including visible light only when the copying stop time before the start of copying exceeds a predetermined time. 0.