JPS62238549A - Exposing lamp control device for copying machine - Google Patents

Abstract

PURPOSE:To suppress a temperature rise of an original platen surface by dimming an exposing lamp instead of turning it off at the time of reset of a scanning optical system, so that it becomes a set value, based on a preliminary turn-on data and an exposure data at the time of the next scan. CONSTITUTION:At the time of an operation of a copying machine, a correct exposure quantity is selected by a key input in accordance with variable density of an original, but an exposure data and a preliminary turn-on data in a storage means 6 are selected, and based on these data, the light quantity of an exposing lamp 4 is controlled so that a set light quantity at the time of exposure, and a preliminary turn-on light quantity at the time of preliminary turn-on can be obtained. When the copying machine enters into a copying operation, a light quantity control operation time control means 8 decides a multi-copy or not from the number of copy sheets, which has been inputted, and commands to dim a light beam to a set light quantity, to a light quantity control means. In this way, at the time of a multi-copy work, during a reset time of a scan optical system, extending from the end of an exposing operation to entering into an exposing operation for the next copy, the light quantity of the exposing lamp 4 is dimmed, therefore, even in case of a continuous copying work, a temperature rise of the original platen surface can be suppressed low.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a predetermined control device for a copying machine that can suppress a rise in temperature of a document placement surface.

Ru.

[Conventional technology]

In an electrophotographic copying machine, a scanning optical system is provided on the lower surface of a document placement surface, and the scanning optical system scans the document while illuminating the document in a predetermined manner to form an image of the document on a photoreceptor.

At this time, at the start of scanning, that is, at the start of exposure, it is necessary that the predetermined amount of light reaches a sufficient amount of light to provide exposure, and after the end of scanning, the predetermined amount of light must be turned off during the process of returning the scanning optical system. However, when the time interval between one exposure operation and the next exposure operation is short, such as in the case of multi-copying where multiple copies are made from one original, the scanning optical system If a predetermined lamp is turned off when the lamp returns, even if the lamp is turned on again at the start of the next scan, exposure may be started without the lamp light intensity rising sufficiently.

For this reason, when multi-copying is performed in a general copying machine or in a high-speed copying machine, a copying operation is executed with a predetermined light on.

However, if a copying operation is performed with the predetermined lights on, the temperature of the document placement surface will rise abnormally due to the heat generated, which not only makes the copying operation dangerous, but is also undesirable for the copying machine.

Therefore, as a countermeasure to this problem, when performing multi-copying, the scanning length of the scanning optical system is set to a certain length or more so that short-distance scanning is not performed, and the time from the recovery of the scanning optical system to the start of the next scanning is A method has been proposed to secure the time from when a predetermined light is turned on again until the light intensity rises to a predetermined value (for example, Japanese Patent Application Laid-Open No. 54-32324, Publication No. 31744, JP-A-54-258
(Refer to Publication No. 38) In addition, measures have been taken such as increasing the amount of cooling air by using a large cooling fan.

[Problem that the invention seeks to solve]

However, when using the above-mentioned proposed means, the copying operation time becomes long (and inefficient). Also, when a large cooling fan is used, noise is generated,
There were problems such as rising manufacturing costs, and a more efficient solution was desired.

[Means for solving problems]

This invention aims to solve the above problems, and first, its principle will be explained.

Figure 2 shows how the light intensity rises from a predetermined turn on, and shows that it takes a certain amount of time td from the time the lamp is turned on until the lamp light intensity reaches 90% of the maximum light intensity, which is sufficient for exposure. show.

Figure 3 is a chart showing the output timing of the lamp lighting signal and the timing of the start and end of exposure. Figure (a) shows that no exposure is performed after the first exposure is completed until the second exposure begins. Since the time T is longer than the time td required for the lamp light intensity to rise to a predetermined value after the output of the lamp lighting signal, the lamp can be turned off after the scanning is completed.

However, the figure (b) is an example of multi-copying, and the time T during which no exposure is performed after the exposure of the first sheet until the start of the exposure of the second sheet is such that the amount of light from the lamp reaches a predetermined value after the output of the lamp lighting signal. This shows that the lamp cannot be turned off even after scanning is completed because it is shorter than the time td required to rise to the value.

Since the time required for the light amount to rise to the predetermined value after turning on the predetermined lamp is constant, in order to raise the light amount to the predetermined value in a short time, it is sufficient to keep the lamp in a dimmed state without turning it off.

Figure 4 shows the situation, and the rise time of the light amount from the dimming state is shown in Figures (b), (c), and (d) as td, t.
As shown in d2°td, it is shorter than the rise time tdO of the amount of light from the off state shown in FIG.

Therefore, in order to deal with the problem explained earlier, it is best to dim the light of the specified lamp without turning it off when the scanning optical system returns, and then raise the light intensity of the lamp to the set value before starting the next scan. I understand that.

Therefore, the predetermined control device of the copying machine of the present invention has exposure data that controls the predetermined light amount set in multiple stages according to the density of the original, and the predetermined light amount is quickly reached based on the exposure data within the set predetermined time. data storage means storing preliminary lighting data set in a plurality of stages corresponding to the exposure data capable of increasing the amount of light; the exposure data stored in the data storage means; and a preliminary corresponding thereto; a selection means for selecting desired exposure data and preliminary lighting data according to the density of the original from the lighting data; When copying the first sheet, a predetermined lighting command signal and a light amount setting command signal are output, and the light amount setting command signal is extinguished in response to an exposure operation end signal;
a predetermined lighting control operation timing control means for outputting a light amount setting command signal at a predetermined time preceding the start time of the second exposure operation and each subsequent exposure operation; A predetermined light amount is set based on exposure data selected by the data selection means in response to a setting command signal, and a predetermined light amount is set based on preliminary lighting data selected by the data selection means in response to disappearance of the light amount setting command signal. The present invention is characterized by comprising a predetermined lighting control means for setting a predetermined light amount as a preliminary lighting light amount.

[For production]

Next, to explain its function, when operating the copying machine, the appropriate exposure amount is manually selected depending on the density of the document, and this selects the exposure data and preliminary lighting data in the storage means. Based on these data, a predetermined light amount control is performed so that the set light amount during exposure and the preliminary lighting light amount during preliminary lighting are achieved.

Preliminary lighting data is set because it is necessary to raise the predetermined light amount to the set light amount within a predetermined time when exposing the second and subsequent sheets during multi-copying, in which multiple copies of the same original are made. The amount of preliminary lighting light is determined in accordance with the amount of light. For this purpose, preliminary lighting data is prepared as a pair with exposure data for predetermined light amount control.

When the copying machine starts copying, the light amount control operation timing control means determines whether or not it is multi-copying based on the input number of copies, and if it is multi-copying, it turns on a predetermined light that is off during the first copy. and instructs the light amount control means to adjust the light amount to the set light amount, and starts the exposure operation after a predetermined amount of time has elapsed since the predetermined light is turned on and the light amount reaches the predetermined amount.

Further, the end of the exposure operation is detected, and the exposure amount is adjusted to the preliminary lighting light amount while the scanning optical system is restored.

When starting the second and subsequent exposure operations,
Instructing the light amount control means to set the light amount for a predetermined amount of time required for the predetermined amount of light to rise prior to the start of the exposure operation;
After increasing the lamp light intensity from the preliminary lighting light intensity to the set light intensity, the exposure operation is started.

From the end of the exposure operation to the start of the next exposure operation, the light is dimmed in a predetermined preliminary lighting state, so that the amount of heat generated during this period can be reduced.

〔Example〕

Examples of the present invention will be described below.

FIG. 1 is a block diagram of a lighting control circuit constituting a predetermined lighting control means. 1 is a microprocessor for predetermined lighting control (hereinafter referred to as lighting control CPU). 2 is a digital/analog converter (hereinafter referred to as a D/A converter),
The light amount control signal outputted from the output ports P2 to P5 of the lighting control CPU 1 is inputted, converted into an analog signal, and outputted to the lamp regulator 3. 3 is a lamp regulator, output port P of CPU 1 for lighting control
The lamp lighting signal outputted from the lamp lighting signal 1 lights up the predetermined 4, and the voltage supplied to the predetermined 4 is controlled by the light amount control signal outputted from the output ports P2 to P5 of the lighting control CPU 1 via the D/A converter 2. control and dim the predetermined 4.

The lamp lighting command signal output from the process control CPU 8 of the copying machine, which constitutes the lighting control operation timing control means, is input to the input capo P6 of the lighting control CPU 1, and the lamp lighting command signal is also input to the input capo P7. CI'U for process control
A light amount setting command signal outputted from 8 that instructs to set the light amount during the exposure operation to a predetermined value is input.

Furthermore, the input port P8 of the lighting control CPU 1. P
9 is an exposure step-up and step-down step for the copying machine operator to select appropriate exposure data from the storage device 6 according to the density of the original (preliminary lighting data is also automatically selected by selecting the exposure data). Key switch SW 1. SW
2 are connected.

Reference numeral 8 denotes a process control CI'U for the copying machine, which constitutes lighting control operation timing control means and also controls the overall operation of the copying machine.

Reference numeral 6 denotes a storage device, which stores exposure data set in multiple stages for adjusting a predetermined amount of light according to the density of the original and preliminary lighting data corresponding thereto, and is connected to the boat P1o of the CPU 1. ing.

Ru.

FIG. 5 shows an example of exposure data stored in the storage device, corresponding preliminary lighting data, and a predetermined voltage supplied by the lamp regulator 3.
During the exposure step, the displays from "Pre+3" to "Pre-3" indicate those during preliminary lighting.

Reference numeral 5 denotes a predetermined power source for lighting the predetermined portion 4 under the control of the lamp regulator 3.

It is.

Next, a predetermined lighting control operation will be explained.

Ru.

The operator of the copying machine determines an appropriate exposure level depending on the density of the original to be copied, and presses the exposure step up and down key switches SWI and SW2 on the operation panel of the copying machine (not shown).
is operated, and a desired one is selected from the exposure data table stored in the storage device 6 via the CPU 1. When exposure data is selected, the corresponding preliminary lighting data is also automatically selected, and these data are temporarily stored in the memory within the CPU I. Then, it is used for subsequent light amount control.

Further, it is assumed that the number of copies is plural, that is, multi-copy is selected.

Referring to the timing chart in FIG. 6, the operation time point becomes clear. When the print key on the operation panel (not shown) is pressed and the start of the copying operation is commanded (time point to
), a lamp lighting command signal is input from the process control CPU 8 of the copying machine to the input port P6 of the lighting control CPU 1, and a light amount setting command signal is also input to the input port P7.

The lighting control CPU 1 receives the lamp lighting command signal and outputs a lamp lighting signal from the output port P1 to the lamp regulator 3 to turn on a predetermined lamp.

In addition, in response to the light amount setting command signal, the exposure data that is selected from the exposure data in the storage device and stored in the memory in the CPU 1 is outputted from the output ports P2 to P5, and the D/A converter 2 The signal is converted into an analog signal and output to the lamp regulator 3.

The lamp regulator receives these signals and turns on a predetermined lamp, and also adjusts the power supply voltage supplied to the predetermined lamp according to the input analog signal to dim the lamp to a predetermined set light amount.

The predetermined light amount is set at tdo after the light amount setting command signal is output.
After a period of time (time point 1+), a predetermined set light amount is reached, and the exposure operation is started from this point.

When the exposure for the first copy ends (time point 12)
, CPU 8 for process control to CPU 1 for lighting control
The light amount setting command signal outputted to the input port P7 becomes 01''F.

In response to the light intensity setting command signal being turned OFF, the lighting control CPU 1 outputs preliminary lighting data selected and stored together with the exposure data from the memo IJK in the CPU 1 from output ports P2 to P5. It is converted into an analog signal via a D/A converter 2 and output to a lamp regulator 3.

The lamp regulator 3 adjusts the power supply voltage supplied to a predetermined value according to the input preliminary lighting data, brings the lamp into a preliminary lighting state, and dims the light.

The scanning optical system returns to the scanning start position, and the exposure operation for the first copy is completed.

Next, moving on to the exposure operation for the second copy, since it is a multi-copy, the next exposure start time can be calculated and determined from the exposure end time for the first copy and the time required for recovery of the scanning optical system. Therefore, the CPU for controlling the copying machine
8, the exposure start time for the second copy (time 1 <
), and the predetermined time preceding that point, i.e., the time it takes for the predetermined light amount in the pre-lighting state to reach the set light amount required for exposure, which is a fixed time determined experimentally. td, a light amount setting command signal is output to the input capo P7 of the lighting control CI'U1 (time ts).

The lighting control CPU 1 outputs previously set exposure data in place of the preliminary lighting data output from the output ports P2 to P5. The output exposure data is input to the lamp regulator 3 via the D/A converter 2, and the lamp regulator 3 adjusts the light to a predetermined set light amount.

The predetermined value is td from the time t3 when the lamp light amount setting command signal is output, and the predetermined set light amount is reached after a period of time t4.
Then, the exposure operation for the second copy is started.

When the exposure for the second copy ends (time t,)
, CPU 8 for process control to CPU 1 for lighting control
The light amount setting command signal output to the input port P7 is turned OFF.

When a third copy is required, as described above after the exposure of the first copy is completed, the predetermined light is turned on and dimmed according to the preliminary lighting data.

The process from setting the exposure amount for the second copy is repeated until the exposure operation for the final copy.
A predetermined number of multi-copies are made.

When the exposure for the final copy is completed, the lamp lighting command signal output from the process control CI'U 8 is turned off, and in response to this, the lamp lighting command signal is output from the lighting control CPU 1.
A predetermined light-off signal is output from the output port PI to the lamp regulator 3, and the light is turned off at a predetermined time.

Lights out.

Next, signal processing for lighting control executed by the lighting control CPU will be explained with reference to flowcharts shown in FIGS. 7 and 8.

FIG. 7 is a flowchart showing an outline of the entire process. First, in step S1, initialization of the CPU and initialization of the controlled object are performed. In step S2, an internal timer for adjusting processing time is set. In step S3, input signals such as exposure step up and down key switches SWI, SW2
It performs processing such as reading input signals from etc. and outputting control data.

In step S4, a predetermined control process is performed, which will be explained in detail later using the flowchart of FIG.

The process advances to step S5', waits for the internal timer to finish counting, and then returns to step 82 to proceed to the next cycle.

Next, the predetermined control routine will be explained with reference to the flowchart shown in FIG.

First, it is checked whether the lamp lighting command signal from the process control CPU 8 of the copying machine is ON or not (step 510).
. If it is ON, check the ramp rise flag (step 5).
11), if F=O1, that is, the first copy, check whether the predetermined light is already lit (step 512), and if it is lit, it is waiting for the predetermined light intensity to rise, so step Move to 816.

In step S12, if the predetermined lamp is not lit, a predetermined lighting signal is output to the lamp regulator (step 513), and the predetermined lamp is lit.

do.

The lamp light intensity rise time tdo is set in the timer (step 514). Subsequently, in order to set a predetermined amount of light as the amount of light necessary for exposure, the exposure data selected by the exposure step up/down key switches SWI, SW2 is output to the D/A converter (S≠, tab 515). As described above, the D/A converter converts this signal into an analog signal, outputs it to the lamp regulator, and dims the predetermined light.

It is checked whether the timer that has set the lamp light intensity rise time has completed timing (step S16), and if the timer has not finished counting, the process ends, but if the time measurement has finished, set the lamp rise flag F to 1. 517), the process ends.

In step SII, when the lamp rising flag is checked and the result is F40, this means copying the second or subsequent sheets, so the process proceeds to step 818, and the light intensity setting command is also output from the process control CI'U of the copying machine. Check the signal,
If it is ON, the set exposure data is output to the D/A converter (step 519), and the process ends. As described above, the predetermined light intensity is adjusted based on the output exposure data.

In step 818, when the light amount setting command signal is OFF, the exposure operation has ended, so in order to reduce the predetermined amount of light, preliminary lighting data is output to the D/A converter instead of the exposure data (step 520). Finish the process. As described above, the predetermined light intensity is adjusted based on the output preliminary lighting data.

In step S10, if the lamp lighting command signal is not ON, it means that the exposure is completed, so step 321
The process proceeds to step 522), where the lamp rising flag F is reset to 0 and the predetermined lights are turned off (step 522), and the process is terminated.

〔Effect of the invention〕

As explained above, according to the present invention, when performing multi-copy work in which multiple copies are made from one original, the scanning optical system is Since the predetermined amount of light is reduced during the recovery time, it is possible to suppress the rise in temperature of the document placement surface even during continuous copying operations. Moreover, since the predetermined light intensity can be raised to the predetermined light intensity in a short period of time just before starting the next exposure operation, there is no need to ensure a special ramp-up time for the lamp light intensity, and there is no time loss due to this. You can perform efficient copying work.

can.

[Brief explanation of drawings]

Fig. 1 is a circuit block diagram showing an example of a predetermined lighting control circuit, Fig. 2 is an explanatory diagram of the rising state of the predetermined light amount, and Fig. 3 shows the output timing of the predetermined lighting signal and the exposure start and end timings. Timing chart, Fig. 4 is a diagram explaining the predetermined turning off and the rising state of the light amount from the dimming state, Fig. 5 is a diagram showing the exposure day i and preliminary lighting data, Fig. 6 is the predetermined turning on and the light amount FIG. 7 is a flowchart showing an outline of signal processing within the lighting control ACPU, and FIG. 8 is a flowchart of a predetermined control routine. Ru. l: lighting control CPU, 2: D/A converter, 3: lamp regulator, 4: M light lamp, 6: storage device, 8
: Process control CPU, SWI, SW2: Switch. 11th! I Figure 2 (b) Figure 3 Figure 4 Figure 5 Leap 6 Figure 7

Claims (1)

[Claims] Exposure data for controlling the light amount of an exposure lamp set in multiple stages according to the density of the original, and increasing the light amount to the set light amount based on the exposure data within a set predetermined time. a data storage means for storing preliminary lighting data set in a plurality of stages corresponding to the exposure data; and a document is stored from the exposure data stored in the data storage means and the corresponding preliminary lighting data. data selection means for selecting desired exposure data and preliminary lighting data according to the shading of the data; At times, an exposure lamp lighting command signal and a light amount setting command signal are output, and in response to an exposure operation end signal, the light amount setting command signal is extinguished, and a predetermined period preceding the start time of the second exposure operation and each subsequent exposure operation is set. an exposure lamp lighting control operation timing control means for outputting a light amount setting command signal to a light amount setting command signal; Lighting the exposure lamp by setting the light amount of the exposure lamp based on the exposure data, and setting the light amount of the exposure lamp to the preliminary lighting light amount based on the preliminary lighting data selected by the data selection means in response to disappearance of the light amount setting command signal. 1. An exposure lamp control device for a copying machine, comprising a control means.