JPH06130512A - Method for controlling exposure - Google Patents

Abstract

PURPOSE:To eliminate the excessive consumption of energy, to reduce the rise of temperature caused by an exposure lamp and to easily execute cooling even in the case of a high lighting voltage by varying the impressing timing of the lighting voltage. CONSTITUTION:Based on a rising time until the finish of rising after the lighting voltage is impressed on an exposure and scanning means, the impressing timing of the lighting voltage is varied. Thus, when the exposure lamp is lighted by the low lighting voltage VL, the value of a low lighting voltage signal is outputted from a control circuit and the lighting of the exposure lamp is started based on the value of a low lighting start time TSL from a return position, a point (b). Besides, when the exposure lamp is lighted by the high lighting voltage VH, the value of a high lighting voltage signal is outputted from the control circuit and the lighting of the exposure lamp is started based on the value of a high lighting start time TSH from the return position, the point (b).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method for an exposure apparatus provided with an exposure scanning means for exposing and scanning a document and a control means for controlling a lighting voltage and a lighting start time of the exposure scanning means. is there.

[0002]

2. Description of the Related Art FIG. 1 is a diagram for explaining the operation of an optical system scanner of an image forming apparatus which is the basis of the present invention. In FIG. 1, 1 is an optical system scanner in which an optical system reciprocates, 2 is a document table on which a document is placed, 3 is a document placed on the document table 2, and 4 is provided inside the optical system scanner 1. Exposure lamp. The optical system scanner 1 turns on the exposure lamp 4 according to the size of the original document in the forward movement, and performs the exposure scanning of the original document 3 along the original document 3 placed on the original table 2.

The light reflected from the document surface is sent to the reflecting mirror M1 by the reflecting portion of the optical system scanner 1 and further reflected by the reflecting mirror M1.
It is reflected by 2, M3 and reaches the photosensitive drum 60. Around the photosensitive drum 60, a charging corotron 40, a developing device 50, a transfer corotron 70, a separating corotron 80, a cleaning device 90, a charge eliminating lamp 100 and the like are arranged. The photosensitive drum 60 is charged by being supplied with a predetermined charge by the charging corotron 40, and the reflected light from the reflecting mirror M3 is irradiated between the charging corotron 40 and the developing device 50 to form an electrostatic latent image.

The electrostatic latent image formed on the photosensitive drum 60 is developed by the developing device 50 into a toner image, which is transferred by the transfer corotron 70 onto a sheet (not shown) conveyed through the path of arrow 115. . The sheet after the transfer of the toner image is separated from the photoconductor drum by the separating corotron 80, is conveyed to the fixing roller 110 via the path of arrow 120, and the toner image is fixed.

After the toner image is transferred onto the paper, the surface of the photosensitive drum 6 is cleaned by the cleaning device 90 to remove the residual toner, further discharged by the discharging lamp 100 and charged again by the charging corotron 40.

An example of a control circuit for the exposure lamp 4 in such an optical scanner is shown in FIG. In the figure, 5 is a control circuit for controlling the exposure lamp 4, 6 is an AC power supply, and 7 is an AC stabilizing power supply circuit for stabilizing the AC power supply 6.

Two signals are output from the control circuit 5. One is a lighting voltage signal S1 and the other is a lamp ON / OFF signal S2. AC stabilized power supply circuit 7
Outputs a predetermined lighting voltage V to the exposure lamp 4 based on the lighting voltage signal S1 and the lamp ON / OFF signal S2, and the exposure lamp 4 is lit with a light amount corresponding to the lighting voltage V.

Now, an example in which the same original 3 is exposed and scanned a plurality of times will be described separately for the first irradiation and the second and subsequent irradiations.

First, at the home position d, which is a position outside the document area before the point a of the document 3 in the optical scanner 1, the control circuit 5 supplies the AC stabilized power supply circuit 7 with the lighting voltage of the exposure lamp 4. The exposure lamp 4 is turned on by sending a lighting voltage signal S1 for determining V and an ON signal of the lamp ON / OFF signal S2. When the light quantity of the exposure lamp 4 rises sufficiently to a value corresponding to the lighting voltage V and becomes stable, the optical system scanner 1 starts the forward movement for irradiating the original 3. The optical system scanner 1 moves to the right in FIG.
After moving to the return position b, which is a position outside the original area behind the rear end, and reaches that point b, the lamp ON / OFF signal S2 of the control circuit 5 is turned off, and the exposure lamp 4
Is turned off, and the optical system scanner 1 ends the irradiation.

The optical system scanner 1 starts the backward movement from the return position b when the exposure lamp 4 is turned off for the first time. The control circuit 5 sends the lighting voltage signal S1 and the ON signal of the lamp ON / OFF signal S2 to the AC stabilized power supply circuit 7 after a certain time T from the return position b to start the lighting of the exposure lamp 4. If a normal return movement can be performed, the position after a certain time T from the return position b becomes the constant position c. When the lighting of the exposure lamp 4 is started from a fixed position c, the exposure lamp 4 rises, a sufficient amount of light is obtained at the above-mentioned home position d, and the preparation for the second irradiation of the original 3 is completed. Then, the optical system scanner 1 uses the original 3
The forward movement is performed to irradiate. The subsequent operation is the same as the first operation. By repeating this operation, the original 3
Is irradiated multiple times.

The timing at which the exposure lamp 4 is turned on is determined by the characteristics of the exposure lamp 4. That is, the rising characteristic of the exposure lamp 4 depending on the lighting voltage V is shown in FIG.
As shown in, the lower lighting voltage VL, the time TU required for rising becomes longer as the time TUL, and the higher lighting voltage VH
The time TU required for rising is shortened like the time TUH, and the relationship is inversely proportional.

Therefore, the lower the lighting voltage VL, the longer the rising time TUL is required. Therefore, the constant position c point at which the exposure lamp 4 starts lighting is the home position d point at the lowest lighting voltage VL used for the exposure lamp 4. At exposure lamp 4
Is determined by the time required to complete the rise of the.

Therefore, when the optical system scanner 1 continuously operates, the exposure lamp 4 rises faster as the lighting voltage VH increases, which causes a rise in temperature, not only on the platen but also on the document 3 and the optical system scanner. 1 Thermal effects are also exerted on the peripheral portion and the inside of the apparatus main body.

[0014]

As described above, according to the conventional lighting control method, the lower the lighting voltage VL, the longer the rising time TUL is, so that the fixed position c point, which is the lighting start time of the exposure lamp 4, is: Since it is determined by the time TUL required to complete the rise of the exposure lamp 4 at the home position d at the lowest lighting voltage VL, as shown in FIG. There is a difference in the completion position of the rising edge of. That is, in the case of the low lighting voltage VL, the rising completion position is the dL point. On the other hand, in the case of the high lighting voltage VH, the rising completion position is the dH point, and from the position dH point to the position d
It means that extra lighting is performed between the L points.

Therefore, the present invention provides an exposure control method capable of eliminating unnecessary energy consumption even in the case of the high lighting voltage VH, reducing the temperature rise due to the exposure lamp 4, and easily performing cooling. Is.

[0016]

According to the present invention, there is provided an exposure apparatus control method comprising: an exposure scanning means for exposing and scanning a document; and a control means for controlling a lighting voltage and a lighting start time of the exposure scanning means. The exposure control method is characterized in that the timing of applying the lighting voltage is varied based on the rising time from the application of the lighting voltage to the exposure scanning means to the completion of the rising.

[0017]

According to the present invention, the timing of applying the lighting voltage is varied based on the rising time from the application of the lighting voltage to the exposure scanning means to the completion of the rising. Lighting can be suppressed.

[0018]

The present invention focuses on the rising characteristics depending on the lighting voltage V of the exposure lamp 4 described above, and controls the lighting timing which has been applied at a constant timing regardless of the lighting voltage V in the related art. It is characterized in that the lighting timing is changed based on the height.

That is, in the present invention, the exposure lamp 4 is based on the rising characteristics of the exposure lamp 4 shown in FIG.
The lighting start time TS is varied according to the lighting voltage V, that is, the lighting voltage signal S1 of the control circuit 5, as shown in FIG.
As a result, when the exposure lamp 4 is turned on with the low lighting voltage VL, the control circuit 5 outputs the value of the low lighting voltage signal S1L, and the low lighting start time TS from the return position b.
The lighting of the exposure lamp 4 is started based on the value of L. Further, when the exposure lamp 4 is turned on with the high lighting voltage VH, the value of the high lighting voltage signal S1H is output from the control circuit 5, and the exposure lamp 4 is output based on the value of the high lighting start time TSH from the return position b. Lighting of 4 is started.

FIG. 6 shows the lighting start time TS varied according to the lighting voltage V of the exposure lamp 4 as described above. The vertical axis of FIG. 6 represents the rising rate, and the horizontal axis represents time. The origin of the horizontal axis has a return position b point in FIG. 1 as an initial value, and time counting starts from the return position b point.

As an example of the method of using the present invention, it can be applied when adjusting the image density.

By operating the density adjustment key on the operation panel, the control circuit 5 receives the information that the instructed density is desired. The control circuit 5 searches the first lookup table for a lighting voltage signal S1 that is set in advance and corresponds to the concentration, and sends the lighting voltage signal S1 to the AC stabilized power supply circuit 7.

Since the lighting start time TS is determined by the lighting voltage signal S1, the lighting start time TS corresponding to the lighting voltage signal S1 is searched for in the second lookup table. When the copy start key is pressed here, the lighting voltage V is applied to the exposure lamp 4 at the home position point d, then the rising time TU is counted, and the scanning of the optical system scanner 1 is started. If you detect the document size,
The exposure lamp 4 can be turned off at the rear end of the original 3. If the second and subsequent exposures are required, the optical scanner 1
When reaches the return position b, the control circuit 5 starts counting time. When the count value reaches the lighting start time TS, the lighting of the exposure lamp 4 is started. Even if the lighting voltage V is changed by the control as described above, the rising is completed at the constant home position d point.

Next, a method of controlling the rising of the low lighting voltage VL and the high lighting voltage VH will be described.

First, the lighting start position of the low lighting voltage VL is
It is a lighting start position CL point which is a position after time TLS from the return position b point. The lighting of the low lighting voltage VL is started from the lighting start position CL, the lighting voltage VL rises as shown by the VL curve in FIG. 6, and the rising rate is 10%.
0% is at the home position d point of the optical system scanner 1.

This time, the lighting start position of the high lighting voltage VH is
It is a lighting start position CL point which is a position after time THS from the return position b point. As described above, time TLS and time T
HS has a relationship of time TLS <time THS. The lighting of the high lighting voltage VH starts from the lighting start position CH point, the high lighting voltage VH rises as shown by the VH curve in FIG. 6, and the rising rate becomes 100% at the home position d of the optical system scanner 1. It is a point.

Therefore, the rate of rising is 100% at the home position d of the optical scanner 1, regardless of the level of the lighting voltage V.

In this embodiment, the rising rate is 100%.
Is the home position d of the optical system scanner 1
The point is that a sensor for detecting the position of the optical system scanner 1 is usually provided at the home position point d, and a sensor for measuring the illuminance is further provided to prevent the exposure lamp 4 from changing with time. It is possible to correct the increase in rise time due to the accompanying deterioration.

As another example, the rising rate is 1
If the time when it reaches 00% is set to the point a of the document 3, the exposure lamp 4 can be used more efficiently.

That is, in order to set the lighting completion position of the exposure lamp 4 to the same position regardless of the lighting voltage, the time to start lighting may be varied according to the lighting voltage V. Lighting voltage V
When the lighting voltage V is high, the lighting start time T is lengthened like THS to delay the lighting start, and when the lighting voltage V is low VL, the lighting start time T is shortened like TLS to start lighting. Should be faster.

By doing so, the time when the rising rate of the exposure lamp 4 becomes 100% is the same position regardless of the value of the lighting voltage V.

As a result, conventionally, when the lighting voltage is VH, useless energy is consumed from the position dH point where the rising rate of the lighting voltage VH becomes 100% to the original home position d point. In the present application, when the lighting voltage VH having a fast rising is applied, by delaying the application timing, unnecessary energy consumption is eliminated, and the temperature rise can be reduced as shown in FIG.

[0033]

According to the present invention, the timing of applying the lighting voltage is varied based on the rising time from the application of the lighting voltage to the exposure means to the completion of the rising, so that the excess energy Consumption is gone,
The temperature rise can also be reduced. Therefore, it is possible to provide an exposure control device capable of easily cooling.

[Brief description of drawings]

FIG. 1 is an operation explanatory view of an optical system scanner which is a basis of the present invention.

FIG. 2 is an exposure lamp control circuit diagram which is the basis of the present invention.

FIG. 3 is a rising characteristic diagram according to a lighting voltage of an exposure lamp.

FIG. 4 is a rising characteristic diagram of a low lighting voltage and a high lighting voltage according to a conventional lighting timing.

FIG. 5 is a characteristic diagram showing a relationship between a lighting start time and a lighting voltage signal.

FIG. 6 is a rising characteristic diagram of a low lighting voltage and a high lighting voltage according to the lighting timing of the present invention.

FIG. 7 is a comparison diagram of temperature rise depending on lighting start time.

[Explanation of symbols]

 1 Optical System Scanner 2 Original Plate 3 Original 4 Exposure Lamp 5 Control Circuit 6 AC Power Supply 7 AC Stabilized Power Supply Circuit

Claims (1)

[Claims] 1. A method of controlling an exposure apparatus, comprising: an exposure scanning means for exposing and scanning an original; and a control means for controlling a lighting voltage and a lighting start time of the exposure scanning means. An exposure control method, wherein the timing of applying the lighting voltage is varied based on the rising time from when the voltage is applied to when the rising is completed.