JPS5844464A - Control method for image formation - Google Patents

Abstract

PURPOSE:To obtain the optimum amount of exposure by varying a disphragm so as to make a drum potential during irradiation by a reference lamp equal to that during irradiation to light reflected from a sampling member with an original exposure lamp. CONSTITUTION:a reference lamp 22 fliskers to form the light part and the dark part on a drum surface and an AC charger 4 and a DC charger 2 are controlled so as to make the result obtained by detecting potentials of those parts with a probe 21 adequate values. An image of a sample member 26 is projected on the drum surface by using an original exposure lamp 24 to measure the potential of the projected part, and then a diaphragm 3 is adjusted by driving a motor 23 so as to make the potential value equal to the potential of the reference lamp irradiation light part when the charger is adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of controlling image formation in electrophotography.

In a copying machine using conventional electrophotographic technology.

The potential on the surface of the photoreceptor, which has up to four effects on the visible image, is affected by variations in the installation of the charger, variations in the voltage of the charging transformer, changes in ambient temperature and humidity, and variations and deterioration in the characteristics of the photoreceptor. Difficult to maintain potential.

Figure 1 shows an example of an electrophotographic device.
The round photoconductor 1 (!Bella 1.01,
O12102, conductive substrate 10B) Table 1141cm/
A light image is exposed through the lens depth S, and an electrostatic snow image is formed at the same time as the static eliminator 4 discharges. A visual image is formed, and the paper cassette is further fed by the paper feed roller 7) 8-b:
The visible image is transferred to a transfer paper 9 by a transfer charger 10, separated by a separation ruler 11), separated from the light body 1, and further fixed by a fixing device 12 consisting of four rollers. (sent to)
It is loaded, fixed, and discharged to F-ray 1S.
When ζO, the photoreceptor 0@Tlja potential obtained in the bright and dark areas at each copying position O'kXJ611 is shown as shown in FIG.

When the humidity around the photoreceptor increases, the two surface potentials at @ILK change as shown in @O in Figure 3, and also as a result of aging of the photoreceptor drum, as shown in Figure 4 (■).

It changes like @O, and the contrast between part 11 and the dark part cannot be obtained. Moreover, it goes without saying that even if the distance from the drum surface of the charger is different from the beginning, the desired value of the potential ① and @O cannot be obtained.

Therefore, the first object of the present invention is to control the copying conditions so that the potential at the zero point is constant under any conditions, as shown by σ and @' in FIG. 5.4. For this reason, the present invention has developed a method of forming an image by forming an electrostatic snow image by charging a photoreceptor and imagewise exposing it (by a pre-post exposure means), and setting a reference value according to the condition of the photoreceptor. The exposure means is controlled according to the set reference value.

In other words, the surface potential is determined in advance by the second ring for exposing the original). It is necessary to adjust the exposure so that the potential is equal to the potential of .

Furthermore, in this embodiment, the detection signal is converted into digital.

Read as a count value,! The Iku-a combinator's judgment function has the characteristics of obtaining an appropriate charge voltage, converting it to analog/pg and applying it to a high-voltage transformer), and obtaining an appropriate amount of exposure and adjusting the exposure.

The present invention will be explained with reference to an embodiment shown in Figure 1. In Figure 1, 21 is a pump for detecting the potential of the photoreceptor surface, 22 is a reference light source, and 69. Mu0
It is possible to irradiate through a static eliminator. 25 is an exposure compensation reversible motor that automatically adjusts the amount of light from the exposure lamp 24;
2S is an aperture adjustment dial, and 26 is a t-mple J[II.

That is, when the reference light source is turned on or off, the potential at point 0 is detected by the surface potential detection probe 21, and the charging transformer is controlled based on that signal, and the potential of the charging transformer is adjusted to obtain the optimum surface potential. If it could be fixed, the original exposure lamp would be turned on without using the primary reference light source to illuminate the sample paper placed at the upper corner of the original table. The exposure diaphragm is varied by rotating the lens drive unit in the forward or reverse direction (by the 9 reversible motor operatively connected) until the confirmed potential becomes equal to the 9σ potential obtained in the first step.

A 1m control circuit using a micro combiator that transforms the above method! I will clarify.

In the figure, the MuD converter converts the input signal into digital data,
The CPU that outputs to the next stage is the above-mentioned MuD converter or Memo 9R.
It is a central control unit that has the functions of reading, converting, decoding, adding and subtracting, logical operations, comparisons, etc. of input and command data from OM and RAM, and ROM operates this control circuit to achieve the above purpose. A dedicated memory for storing the rounding procedure (program), a writable memory for temporarily storing the data for the four-gram processing, and an output device 1 for supplying the current of the component (0AO) lance HVT; Outputs a signal to set the voltage. Similarly, the output device 2.5 is
Voltage of the component Muro transformer, Do) Outputs a signal to set the voltage of the lance.

The output device 4.5 is a device for outputting signals for on/off control of the AC high-voltage transformer, Do high-voltage transformer, main drive motor, full-surface exposure lamp, reference light source, N exposure lamp, exposure aperture) control reversible motor. , ζO signals are also connected to the actual load Kll through the interface circuit. The outputs of the high-voltage transformers 1 and 2 are connected to each other through 10 diodes in opposite directions, but this means that the high-voltage transformer 1 outputs only the 0 component, and the AC high-voltage transformer 2 outputs only the O component. This is in order to output , and also to make the O component>■ component. This is because the static electricity is eliminated by the difference between the two power components, so in Figure 5.4, the input voltage of the high-voltage transformer 20 is increased so that the voltage of the O component is increased when rounding from @ to @. In addition, the input voltage of the tsunos O is increased (DC for llK).

The input device detects a clock signal for the copy sequence depth, a drive position (home) signal, a register for transfer timing, the concentration of the current agent in the register, a jam, etc., and inputs a good signal (not shown).

Dmu 1~! I is a D-mu converter which converts the digital signal from each output device 1 to S into an analog quantity and outputs the voltage to the high voltage transformer HV TE1 to black and DO high voltage transformer. ] Output tie ζ blowfish is determined. The upper IE ROMK stores a program for controlling the potential (by a two-chart such as the 450). The above RAM contains the optimum potential of MuC, O potential and DC.
The optimum potential of is stored in advance.

The operation will be explained based on the FIG. 6C) 70-chart. Prior to the copy cycle, the address of the CPU d output device (1) is specified via the address path, and the high voltage transformer 10 is
A two-pass signal for setting a predetermined potential is output to the output device (1) via the data bus. This is converted into an analog quantity by the D-M converter, and the M-C high voltage transformer 1
Give a potential to. However, at this point, the control signal line ■ of the D-me converter is not set.

It only transfers the data to the output device (1).

Subsequently, the predetermined two-way signal is similarly transferred to the output devices (2) and (5). Furthermore, the address of the CMB output device (5) is specified, and the 2 over code 1000 is outputted to turn on the main drive motor.

This is the code when the output device (5) can output 4 bits in parallel, and it is output via the data e* (hereinafter referred to as data bus), and the main screen waits until the totsum on rotation becomes constant. ! - works (sp-2) and waits for the next 0 execution, and when the time-up occurs, the output device (4) K CPU outputs 2 overcode 1111, and the primary high voltage transformer
High voltage transformers 1 and 2, gold side exposure lamp, reference light source oM
(op-5)

8P-4 to 8F-14 are routines that turn on the reference light source and change the high-voltage transformer 2 to find the appropriate value for the bright area potential of the photosensitive drum. 8P-1s to 8P-24 are routines that turn on the reference light source 01? In this routine, the DCC high voltage transformer is changed to find an appropriate value for the dark area potential of the photosensitive drum.

The flag, also called KFlag, is used to determine whether or not to execute the program.

If you change the Do high voltage transformer in 8P-15 to 8F-24, it will also change the electric potential of the light part, so please re-hi 8P-1.
A loop α is provided to return to the 5-8P-240 routine and check again. Flag 1 is the bright part.

Flag 2 and Flag 5 are provided so that both potentials in the dark area are at appropriate values and number 9 can be confirmed at 5p-27.
does not generate spark discharge, so 8P-4 to 5IF-1
It is provided in the rounding to remember that the voltage limit has been reached at 4°8P-15 to 8P-24. Therefore, when 7111g2 is set, the routines 8P-4 to 8P-14 are not executed, and when Flag5 is set, 8P-14 is not executed.
15 to 5P-24 are not executed, and the program is forced to proceed to the later program.

8P-28 to 8P45 are set by 8P-4 to 8P-14. The original exposure lamp is turned on so that the potential IC is equal to the potential set by 8P-14, and the control motor is rotated forward or reverse to obtain the appropriate light amount. This is a routine to set the .

When this is finished, turn off all the loads at 82-56 (
copy cycle).

The above is an example of obtaining the optimum potential for a standard color tone, and a reference light source and sample paper corresponding to that color tone are provided. The color tones of originals vary, so after setting the appropriate aperture, the operational connection between the lens drive unit, motor, and O is released, and instead it is replaced by a diaphragm that is operatively connected to the adjustment dial, so that it can be adjusted to match the color tone of the original. You can obtain images using

From the four-chard in Figure 6 above, the general-purpose o-v
41 El 27 Hiz-p (s-00M4.XM
TRX.

It is easy for those skilled in the art to create a program step using a dedicated instruction code using the 8060 series.

The timer is set in advance by setting the timer time RJ & fg = r −
)", and by providing a routine that sequentially subtracts this code one by one and determines whether it has become O, but it can be done by providing an external tie! means and tying it with the control circuit 00ut. !It is also possible to set it to start and use the x turtle to detect time-up.

Also, when the check zone where the reference light and the sample light are irradiated on the circumference 11 of the photosensitive drum is sanded, during the copy cycle -t'4
becomes controllable.

In the step of calculating the reference value and the step of performing dew control, the amount of time required is 9 m1 dl.If the photosensitive dot deteriorates due to the conversion to the A section, in order to change from ■→■/, 0→α in Figure 4. Although it is necessary to increase the potential of the primary charging transformer and static elimination transformer,
The upper limit of this potential must be below the spark discharge starting voltage, so the potential of This is the ninth thing to keep the settings. and.

In addition to not using a base light source, if you use the light from the original exposure lamp, the amount of emitted light will vary depending on the instability of the light intensity of the original exposure lamp and the setting value of the exposure diaphragm 9 adjustment dial. Therefore, in the first step, we set up a reference light source that does not pass through the lens system and set the appropriate surface potential, and then varied the aperture in two steps. So I decided to look again at the appropriate value.

As described above, in the present invention, a reference value is set according to the condition of the photoreceptor, and exposure is controlled according to this reference value, so that deterioration of the exposure lamp and photoreceptor drum i can be corrected. ,!
A constant image can always be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an electrophotographic device. Figure 2 is a diagram showing the surface potential in Figure 111. Figure 113 is a diagram showing surface potential change (E) with respect to humidity. Figure 4 is a diagram showing changes in surface potential over time. Figure 5 is a stabilizing device of the present invention. Figure 6 is a flowchart showing the procedure for surface stabilization (as shown in Figure 5). 21 is a one-stroke potential detection module, 22 is a base * light source. 23 is a 11 is a motor for printing, 24 is an exposure lamp, and 26 is a simple original. Applicant: Canon Kinsha Co., Ltd.

Claims (1)

[Claims] In a method of forming an image by forming an electrostatic latent image by charging a photoreceptor and exposing it imagewise using a pre-post exposure means, a reference value is set according to the condition of the photoreceptor, and according to the reference value. An image formation control method characterized by: controlling the exposure means by using the following steps.