JPH0612399B2 - Exposure lamp control device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure lamp control system for an electronic copying machine, and more particularly, it accurately determines the set value and the amount of light emitted from the exposure lamp by taking into account the nonlinearity of the exposure lamp output. It is designed to match.

[Conventional technology]

In an electronic copying machine, the copy density can be adjusted in five steps of, for example, dark-slightly dark-normal-slightly-light. In this case, when the copy density is high, the exposure amount of the exposure lamp is reduced and the lightness is decreased. It is necessary to increase the exposure dose. For this reason, a semiconductor switch such as a triac is used to adjust its firing angle and control the exposure lamp voltage.

A conventional exposure lamp control circuit is shown in FIG.

In FIG. 7, 1 is an exposure lamp, 2 is a triac,
3 is an AC power supply, 4 is a light amount monitor circuit, 5 is an amplifier circuit, 6
Is a microcomputer, 7 is a gate circuit, and 8 is a light amount adjusting volume. The light amount of the exposure lamp 1 is controlled by controlling the firing phase of the triac 2 by the gate circuit 7 to control the voltage applied to the exposure lamp 1.

Now, setting the amount of light in 5 steps from 1 to 5,
Taking the case where the copy density is set to be lighter in step 1 and darker in step 5, for example, step 1 has the highest light intensity and step 5 has the lowest light intensity. Then, in step 1, the output power V ₁ of the volume 8 is set to V ₁₁ corresponding to step 1, and the output of the volume 8 is set in five stages of V _{11 to} V ₁₅ corresponding to step 5 below.

The output light of the exposure lamp 1 is detected by the light amount monitor circuit 4. The light quantity monitor circuit 4 is provided with a photoelectric element and outputs a voltage according to the output light of the exposure lamp 1. The output of the light quantity monitor circuit 4 is amplified by the amplifier circuit 5 and transmitted to the microcomputer 6. Micro Computer 6
Is provided with a comparison unit 6-1. When the light amount set value V ₁ in the volume 8 and the output V ₂ of the amplifier circuit 5 are transmitted to the analog port, these are compared to the A / D converter A / D.
_It is converted into a digital value by ₁ and A / D ₂ , and these are compared by the comparison section 6-1. Then, the output of the comparing section 6-1 sends a control signal to the gate circuit 7 so that these V ₁ and V ₂ become equal to each other, and the firing phase of the triac 2 is controlled. As a result, the exposure lamp 1 in the state of V ₁ = V ₂
Will be controlled.

[Problems to be solved by the invention]

By the way, as described above, the voltage V ₁ set by the light quantity changing volume 8 and the light quantity monitor circuit 4 detect the voltage V ₁ and the amplifying circuit 5
The gate circuit 7 of the triac 2 is controlled so that the output voltages V ₂ become equal to each other to control the voltage of the exposure lamp 1 to a desired value. However, this has the following problems.

That is, the relationship between the light quantity of the exposure lamp 1 and the lamp voltage applied to both ends of the exposure lamp 1 has a non-linearity like a square characteristic as shown in FIG. 2, and is not a linear relationship. .

Therefore, the relationship between the light amount set values 1 to 5 and the output light amount of the exposure lamp 1 is as shown by the dotted line in FIG.
For example, the ignition phase of the triac 2 is controlled in a state where the set voltage V ₁₂ and the output V ₂₂ of the amplifier circuit 5 become equal when set in step 2. Now, when the triac 2 has the maximum light amount (that is, step 1), the applied voltage is 60V.
If the applied voltage is 50V at the minimum light quantity (that is, step 5), the characteristic is shown by the dotted line. For example, at step 2 (V ₁₂ ), the control is performed at V ₂ ′ where the applied voltage is more than 58V. , Which is different from the theoretically correct V ₂₂ .

Therefore, there is a problem in that the desired light amount cannot be obtained at the desired setting position of the volume 8 even by the control of the microcomputer 6.

[Means and Actions for Solving Problems]

In order to solve the above-mentioned problems, in the exposure lamp control device of the present invention, an exposure lamp, an opening / closing element for controlling ON / OFF of the power supply of the exposure lamp, and a light emission amount detection means for detecting the light emission amount of the exposure lamp, A light emission amount setting means for setting the light emission amount of the exposure lamp according to the selected copy density; a calculation means for performing a non-linear calculation of the light emission amount set by the light emission amount setting means and outputting a calculation result; Comparing means for comparing the calculation result output by the means with the light emission amount detected by the light emission amount detecting means, and the light emission amount detected by the light emission amount detecting means based on the output of the comparing means by the calculating means. A gate circuit is provided to control the opening / closing timing of the opening / closing element so that the output calculation result becomes equal.

As a result, the set voltage can be matched to the characteristics of the exposure lamp, so that the exposure lamp can be accurately controlled and copying can be performed at the density set by the user.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a configuration diagram of an embodiment of the present invention, FIG. 2 is a characteristic diagram of a lamp voltage and a light intensity of an exposure lamp, and FIG. 3 is a variable density (variable light amount) installed on a control panel in an electronic copying machine.
The adjusting portion of the volume, FIG. 4 is a characteristic diagram of the set value of the volume and the light amount of the exposure lamp, FIG. 5 is a flow chart showing the operating state of the present invention, and FIG. 6 is a voltage control state explanatory diagram.

In FIG. 1, 1 is an exposure lamp, 2 is a triac,
3 is an AC power source, 4 is a light amount monitor circuit, 5 is an amplifier circuit, 7
Is a gate circuit, 8 is a light quantity adjusting volume, 10 is a microcomputer, 11 is an adjusting plate, 12 is a groove, and 13 is an indicator in FIG.

In FIG. 1, the same parts as those in FIG. The microcomputer 10 shown in FIG. 1 corresponds to the microcomputer 6 shown in FIG. 7, but has a calculator 10-2 in addition to the comparator 10-1.

The calculation unit 10-2 calculates the light amount setting value V ₁ of the volume 8 as the _first value.
As shown by the dotted line V ₁ ′ in the figure, the calculation is performed so as to approximate the V ₂ curve.

The adjusting plate 11 is provided with a groove 12, and the indicator 13 moves the groove 12 left and right. When the semi-circular black-and-white boundary portion of the indicator 13 is located at the instruction mark 1, the setting value of the volume 8 becomes the lightest copy density setting value of step 1, and when it is located at the instruction mark 5, it is the darkest. The copy density becomes step 5, and the applied voltage of the exposure lamp 1 is determined so that the copy density is in the state indicated by these.

Next, the operation of the present invention will be described based on the order shown in the flowchart of FIG.

(1) When making a copy, the operator operates the instructing section 13 to specify the copy density, and presses the start button.

(2) The microcomputer 10 reads the output voltage V ₁ of the volume 8 output based on the designation of the copy density, sets it as x, A / D converts it, and inputs it to the arithmetic unit 10-2.

(3) The calculation unit 10-2 of the microcomputer 10 calculates y = x ² + a by this x (x = V ₁ ) and outputs this output y to the comparison unit 10-1. Here, a is an initial value.

(4) By the way, the output of the exposure lamp 1 is detected by the photoelectric element of the light quantity monitor circuit 4, this is amplified by the amplifier circuit 5, and becomes the output voltage V ₂ according to the light quantity of the exposure lamp 1, which is A / D converted. The y = x ² + a transmitted to the comparison unit 10-1 and sent from the calculation unit 10-2 is compared with this V ₂ .

(5) The comparison unit 10-1 controls the PD output so that V ₂ = y and sends it to the gate circuit 7. That is, when V ₂ <y, the comparison unit 10-1 sends a control signal to the gate circuit 7 so as to accelerate the firing time of the triac 2 and increase the voltage applied to the exposure lamp 1, and V ₂
When> y, a control signal is sent to the gate circuit 7 so that the firing time of the triac 2 is delayed to reduce the voltage applied to the exposure lamp 1, and when V ₂ = y, the firing time is changed. The gate circuit 7 is controlled so as not to change it. Therefore, the comparing unit 10-1 may generate the sixth signal according to the states of V ₂ and y.
The PD output in the state as shown in the figure is sent out. Then, control is performed so that V ₂ = y, and thus copying with a predetermined density is performed.

〔The invention's effect〕

According to the present invention, the set value and the detected value can be compared with each other in a state where the voltage-light emission characteristic matches the non-linear characteristic of the exposure lamp, which is almost a square characteristic. It is possible to accurately control the state of, and surely copy at the copy density set by the user.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention, FIG. 2 is a characteristic diagram of a lamp voltage and a light amount of an exposure lamp, FIG. 3 is a volume adjusting unit in an electronic copying machine, and FIG. 4 is a set value of the volume. FIG. 5 is a flow chart showing the operating state of the present invention, FIG. 6 is a voltage control state explanatory diagram, FIG. 7 is a conventional configuration diagram, and FIG. 8 is a conventional problem. FIG. 1 ... Exposure lamp, 2 ... Triac, 3 ... AC power supply, 4 ... Light intensity monitor circuit, 5 ... Amplifier circuit, 6 ... Microcomputer, 7 ... Gate circuit, 8 ... Volume, 10 ... Microcomputer, 11 …… Adjustment plate 12 …… Groove, 13 …… Indicator

Claims (1)

[Claims] 1. An exposure lamp, an opening / closing element for controlling on / off of a power source of the exposure lamp, a light emission amount detecting means for detecting a light emission amount of the exposure lamp, and a light emission of the exposure lamp according to a selected copy density. A light emission amount setting means for setting the light emission amount, a calculation means for performing a non-linear calculation of the light emission amount set by the light emission amount setting means and outputting a calculation result, a calculation result output by the calculation means and the light emission amount detection means Comparing means for comparing the light emission amount detected by the opening and closing means so that the light emission amount detected by the light emission amount detecting means based on the output of the comparing means becomes equal to the calculation result output by the calculating means. An exposure lamp control device comprising: a gate circuit for controlling the opening / closing timing of the element.