JPH024906B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to a method for setting an optimum lamp voltage for a copying machine or the like. As is well known, copy quality in an electronic copying machine is largely affected by the voltage applied to the document illumination lamp. That is, if the applied voltage is too low, the amount of light will be insufficient, resulting in a dirty copy with poor background color. On the other hand, if the applied voltage is too high, the amount of light will be too large and the image itself will disappear, resulting in a pale and blurred copy. Therefore, in order to obtain high-quality copies, it is necessary to select an appropriate voltage to be applied to the document illumination lamp. Conventionally, the selection and adjustment of the voltage applied to the lamp has been done by feeling, which has resulted in the disadvantage that the adjustment requires a long time and skill, and that the voltage cannot be adjusted by beginners. Further, even after adjusting the lamp applied voltage to the optimum value under certain copying conditions, if the copying conditions (magnification, paper size, etc.) change, the optimum value must be corrected. Furthermore, as time passes, if dust adheres to lenses, reflectors, etc. inserted in the optical path from the lamp to the photosensitive drum, the amount of light that actually reaches the irradiated surface of the document decreases, and there is a risk that the amount of light will be insufficient.
Also, after cleaning the lenses and reflectors mentioned above,
Too much light often occurs. In such a case, it is necessary to adjust the applied voltage again. As described above, the voltage applied to the document illumination lamp in a copying machine must be adjusted quite frequently, and is one of the troublesome tasks in maintaining the copying machine. SUMMARY OF THE INVENTION An object of the present invention is to provide a method for setting a voltage applied to a lamp of a copying machine, which eliminates the drawbacks of the above-mentioned prior art and allows the voltage applied to a lamp for document illumination to be easily set to an optimum state. The present invention is characterized by employing the following steps. (1) After turning on the power, set a specific magnification and set the lamp light intensity to the minimum. (2) Regarding the set magnification, compare the optimal lamp light intensity determined in advance with the lamp light intensity set to the lowest value. (3) Gradually increase the voltage applied to the lamp to increase the lamp light intensity and find the optimal lamp light intensity (or
(or higher), repeat the above operations. (4) Store the applied voltage when the optimum lamp light intensity (or more) is reached. (5) Next, change the magnification in (1) above and perform the same procedure as above to find and store the optimum applied voltage for each of the plurality of magnifications. An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic block diagram of an optimal lamp applied voltage setting device suitable for carrying out the present invention using a computer, in which 1 indicates a CPU (central processing unit);
2 is ROM (read only memory), 3 is
RAM (Random Access Memory), 4 is input port, 5 is output port, 6 is CPU1, ROM
2, RAM3, input port 4 and output port 5
10 is the input port 4
and a copying machine main body connected to a computer section (CPU 1, ROM 2, RAM 3, etc.) via an output port 5. The inputs and outputs directly necessary for implementing the invention are as illustrated in FIG. That is, input: Copying magnification signal: Lamp light intensity sensor output signal: Lamp applied voltage stage number: Fuser temperature setting signal Output: Lamp applied voltage signal Magnification optical system movement signal In addition, in this embodiment, the lamp applied voltage is 1
It is assumed that eight levels are set in advance as shown in the table.

[Table] Next, referring to the flowchart in Figure 2,
An embodiment of the method of the present invention will be described. In the following description, a case will be described in which only the copying magnification is changed as a copying condition, but the present invention can be implemented in the same manner even in cases where other copying conditions are changed. When the power is turned on in step S1, the step
At S2, it is determined whether warming-up has ended. Specifically, it is determined whether the temperature of the fixing device has become higher than a preset temperature input. If the temperature of the fixing device is lower than the set temperature, that is, if warming-up has not been completed, the process advances to step S3, and time is measured. In step S4, a check is made to see if the measured time exceeds the execution grace period. Here, the execution grace period is defined as follows. FIG. 3 shows an example of the time required for warming up, and whether or not warming up is completed is determined based on the temperature of the fixing device. When you start the copying machine after turning it off for a long time, the temperature of the fuser is almost at room temperature ( _T1 in Figure 3) at the time of startup, so the temperature will be as shown by curve a in the figure. First, the temperature starts from T ₁ and reaches the set value at time T ₀ , which is considered to be the completion of warming up. However, if the power off time of the copying machine is short, the temperature of the fixing device has not completely decreased, so when the copying machine is started, it starts to heat up from a temperature T ₀ above room temperature. Therefore, the time it takes for the fixing device to reach the set temperature is short, t ₁ (<t ₀ ). Here, an appropriate value t ₂ smaller than time t ₀ is defined as the execution grace time. In practice, a value slightly smaller than time t ₀ is appropriate. In step S4, if the time measured in step S3 has not expired, the process returns to step S2, and it is determined whether the warming-up has ended. Now, before completing the warm-up,
When S4 determines that the execution grace period has expired, the step
Proceed to S5 and a certain magnification is set. Next, in step S6, the lowest voltage step 1 of the voltages applied to the lamps in Table 1, ie, 120V, is set. The voltage level is then stored in step S7. Next, the process proceeds to step S8, and the copying machine causes the lamp to emit light using the applied voltage. Then, in step S9, the light intensity of the lamp is compared with a set value of the optimum lamp light intensity corresponding to the magnification, which is stored in advance in the computer, and it is determined whether the light intensity of the lamp is larger than the set value. . In this case, specifically, the amount of light from the lamp is converted into a voltage value by a sensor, and this voltage value is taken into the computer. This is then performed by comparing the sensor output voltage values a, b, c, . . . for the optimum lamp light quantity shown in Table 2.

[Table] If the lamp light intensity is lower than the set value, the step
Proceeding to S10, it is determined whether the lamp light intensity is at its maximum, that is, whether the voltage level in Table 1 has reached its maximum. If the determination in step S10 is not satisfied, the light intensity of the lamp is increased by one level in step S11.
In other words, it will be moved up from the level shown in Table 1.
This allows the voltage applied to the lamp to be, for example, 125V.
become. The procedure from steps S7 to S11 is repeated, and when it is determined in step S9 that the amount of light from the lamp exceeds the set value, the process proceeds to step S12, and then
The voltage level of the highest voltage for the magnification set in S5 is memorized. Through the above procedure, the optimum applied voltage for the initially set magnification is determined. Subsequently, in step S13, it is determined whether the optimum applied voltages for all the settable magnifications of the copying machine have been determined. If the judgment here is not satisfied, step S14 is applied to the magnification that has not been performed yet.
is changed, and the procedures from step S6 described above are executed. Then, the optimum applied voltage for this changed magnification is determined, and in step S12 the voltage stages for that voltage value are stored. When the optimum lamp applied voltage for all magnifications is determined in this way, the optimum voltage stages are stored in the nonvolatile memory for each magnification (step S15). The reason why the data is stored in a non-volatile memory is to retain the data at the optimum stage even when the power is turned off, since copying machines are often turned on and off. Next, the normal copy cycle (step S16)
Move to. In a normal copy cycle, a lamp voltage corresponding to the magnification set by the operator is applied to the lamp, and copying is performed under the optimum amount of lamp light. On the other hand, if the warming-up ends before the execution grace period expires at steps S2 to S4, the process proceeds to step S17 without performing the operation of determining the lamp applied voltage corresponding to the magnification as described above. In step S17, the data stored in the nonvolatile memory is read out to the volatile memory. Then, the process advances to step S16 and the copying operation is executed. That is, at this time, the lamp applied voltage is set using the data stored in the nonvolatile memory during the previous copying operation. In this case, the fact that warming-up has finished before the execution grace period expires means that not much time has passed since the last copying operation, so the voltage applied to the lamp should be reduced. Good copying can be performed even if the copying operation is the same as the previous copying operation. Further, by doing so, unnecessary work for setting the optimal lamp voltage can be omitted, and time loss can be prevented. In the above embodiment, steps S2 to S4 are provided,
Although the optimal lamp voltage setting work is omitted when not much time has passed since the previous copying work, it is of course possible to perform the optimal lamp voltage setting work every time the power is turned on. It is clear that steps S2 to S4 can be omitted at this time. In this case, step S15 of storing the optimum voltage levels for all magnifications in the nonvolatile memory becomes unnecessary. Furthermore, in the case of a copying machine that does not have the function of changing the magnification, it goes without saying that steps S5, S13 and S14 in FIG. 2 are not required. As described above, according to the present invention, the optimum lamp voltage can be easily and quickly set without any skill required, and good copying can always be performed.

[Brief explanation of drawings]

Fig. 1 is a block diagram of the optimum lamp applied voltage setting device used in the present invention, Fig. 2 is a flowchart for explaining one embodiment of the present invention, and Fig. 3 is the execution grace period ( FIG. 4 is an explanatory diagram for explaining the definition of step S4). 1...CPU, 2...ROM, 3...RAM, 4
...Input port, 5...Output port, 10...Copier main body.

Claims (1)

[Scope of Claims] 1. A document illumination lamp, a copying magnification selection means, a nonvolatile memory means for storing the optimum lamp applied voltage for each magnification, and an optimum lamp applied voltage stored in the nonvolatile memory. and a control means for controlling the document illumination lamp during copying at a selected magnification, the temperature of the fuser is adjusted to a set value that enables copying within a preset time after power is turned on. If the temperature of the setting device has not reached the set value that can be copied within the specified time, use the following procedure to find the optimal lamp applied voltage for each magnification and set the specific magnification. The voltage applied to the lamp is increased stepwise from a predetermined minimum voltage, and the applied voltage when the amount of light emitted by the lamp becomes equal to or greater than the optimal amount of light emitted for the set magnification is determined as the optimal lamp applied voltage for the set magnification. Change the magnification and perform the above operation for other magnifications to find the optimal lamp applied voltage for each of the multiple magnifications. control the document illumination lamp using the optimal lamp applied voltage of the newly stored non-volatile memory, and when the temperature of the setting device reaches a set value that allows copying within the specified time; A method for setting a lamp applied voltage for a copying machine, characterized in that the document illumination lamp is controlled using an optimum lamp applied voltage already stored in a non-volatile memory.