JPH0317670A - Electric power controller for copying device - Google Patents

Abstract

PURPOSE:To more effectively reduce electric power when an exposure lamp reciprocates by controlling the light quantity resetting timing of the exposure lamp according to a set copying magnification. CONSTITUTION:When the set copying magnification (m) is changed from m=100% to m=64%, T=141msec (845-11X64) is read out from a timing table 38 with respect to a time T deciding the light quantity resetting timing of the exposure lamp 12. The exposure lamp 12 after 141msec from the falling of a scanning completion signal is supplied with electric power which should be its suitable light quantity. As for the above mentioned light quantity control of the exposure lamp 12, since time T from the falling of the scanning completion signal that decides the light quantity resetting timing of the exposure lamp 12 is set longer at the lower copying magnification. Consequently, even at a low copying magnification (m) (=64%), decrease in the quantity of the exposure lamp 12 can be maintained until a lower timing. Therefore, a peak electric power at the low copying magnification is effectively reduced.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a copying machine using a scanning exposure lamp that illuminates the surface of a document by reciprocating relative to the document according to a set copying magnification. The present invention relates to a power control device which controls an exposure lamp at a predetermined appropriate amount of light during forward movement and reduces the light d of the exposure lamp during return movement.

[Prior Art] Conventionally, the inventors of the present invention have proposed an electrophotographic copying machine having a scanning system structure as shown in FIG. 4, for example. (Refer to Publication No. 57-86852 of M.A.). This is the type that scans the original with the original in place, and the platen 1 on which the original is placed.
Mirrors 13, 14, along with the exposure lamp 12,
15, the lens system 16 and mirrors 17, 18, 19 are arranged in sequence, and the exposure lamp 12 and mirrors 13, 14, 15
, 17, 18, and 19 are configured to reciprocate in the lower part of the braun 11. During the reciprocating process of the exposure lamp 12, etc., reflected light from the 12 originals placed on the platen 11 passes through the mirror lens system ii! i is guided to the surface of the photoreceptor belt 20 on which the imaging process is to be carried out.

Incidentally, a charger, a developer, various static eliminators, a cleaning neck, and the like are arranged around the photosensitive belt 20 to execute the image forming process (not shown).

In recent medium-high speed copying machines, the reciprocating movement of the scanning system including the exposure lamp 12 as described above is performed by a servomotor.
The speed profile of the reciprocating motion is, for example, shown in Figure 6 (l
It is shown by the solid line. That is, after starting the forward scanning <time to, t1>, the exposure lamp 12 is maintained at a constant scanning speed V (JII11) and the original is scanned (l:2→t3), and the original is scanned at When the servo motor is finished (t3), the brake is applied to the servo motor, and it moves directly to the return movement.In this return movement, in order to return the scanning system to the initial position as soon as possible, the scanning speed V (a speed greater than + The scanning system is maintained at Vb, and the brake is applied again at a predetermined position (t4), resulting in a stop (t5).In the case of continuous copying, after the stop, the scanning system moves to the next document scan at a predetermined timing ( →t7), the same speed prono aisle drive control as above is repeated.

Focusing on the drive control of the scanning system as described above, the speed of the scanning system increases especially during backward movement, and since the brakes are applied to the servo motor, the total machine power in the copying machine is, for example, As shown in Figure 5, after the start of the return motion, the input line current gradually rises from a steady state (input line current 11), and just before the return motion ends and the scanning system stops, the peak (input line current I) increases.
]1).

In view of such power consumption characteristics, it has been proposed in the past to reduce the light amount of the exposure lamp 12 during the backward movement from the appropriate light amount to reduce the peak value of power consumption during the backward movement.

Specifically, as shown in FIG. 6, for example, the light source of the exposure lamp 12 is lowered (e.g., tube current 0.6^) from the start of the return (t3), and the return is completed. After that (
After a predetermined time T from t5), the appropriate light maximum (for example, @current 1
．． 2A).

In this way, it is possible to reduce the peak value of the entire power consumption during the backward movement by the amount of the decrease in the light base of the exposure lamp 12.

Generally, in this type of copying machine, the scanning range and scanning speed differ depending on the set copying magnification, but since the correlation between the scanning range and the scanning speed with respect to the magnification is inverse, the scanning R interval is It remains approximately constant. Therefore, since the return movement end timing is constant for each set copy magnification, the above return timing (time J
．． 'l T ) can be determined.

However, if the scanning time etc. differs depending on the set copying magnification in order to achieve more efficient scanning, for example, the timing for returning the light intensity of the exposure lamp should be determined by taking the set copying magnification into consideration. Become. As an example of this, in the conventional copying machine proposed by the inventors of the present invention (see FIG. 4 for its structure), the timing of return of light flI1 is controlled as follows.

First, the speed control (steady speed) of the scanning system, which is a prerequisite, is performed as follows according to the copying magnification m (%).

The speed vim of the exposure lamp 12 and mirror 13 (scanning speed V
o) is V1m=Vp-K/ (m-K-1>vp: Moving speed of the photosensitive belt 20 K: PIS constant (predetermined constant) The speed V2 of the mirror 14.15 is V2m=V1m/ 2 The speed V4m of the mirror 19 is controlled to be V4a=V1m/K The speed V3m of the mirror 17.18 is controlled to be V3m=V4m/2, and further, the speed 1m and the movement of the photoreceptor belt 20 are Between the speed Vp, m − V1m
The relationship =Vp +V4m holds true (if it does not hold, a correct projected image cannot be obtained). In this way, if the exposure position 4 is moved on the photoreceptor belt 20 by controlling the mirror 17, 18 at a speed of V3m and the mirror 19 at a speed of V4mkm, the interface on the photoreceptor belt 20 can be moved in the case of continuous copying. The image area can be made smaller. As a result, the copy speed can be improved without particularly increasing the process speed.

In addition, the above PIS (Precession Image)
ing Systcn+ ) Constant K will be explained. This PIS constant KG can take any value if m-K-1>O, that is, K>1/m. For example, if (1.64 (64%) ≦ (71 (. 2 (200X)), then any value can be taken if K > 1.5625, but in reality, for example, vp = 309 ays/SQC, K = 1.6, m = 0.64 (64%) and V 1m = 30
9x 1.6/(0.64 - 1.6-1) =
This results in an unrealistic scanning speed of 20,600 m/SeC.

Also, in the case of K=10, m=1.0 (OOX),
v1m=309X10/(1-10-1)=
It became 343.3g+/Sec, PIS! i! I
The advantage of being a III will be lost.

Depending on the applied magnification range, this usually results in P
The IS constant aK is selected within the range of 2.5≦K≦4.

When the speed of the scanning system is controlled in accordance with the set copying magnification m as described above, the lower the magnification, the greater the scanning speed, and the degree of increase is greater than the increase in the scanning range. As a result, if the set copy magnification is low, for example, as shown by the broken line in FIG.
→t3゜) becomes shorter, and accordingly, the return movement (return)
The end timing (t4') becomes earlier. In this way, when the backward movement end timing changes according to the set copying magnification m, the time T from this backward movement end timing to the light circle return timing of the exposure lamp 12 is as follows: That is, assuming the case where the set copying magnification m becomes the maximum, the timing is determined at the latest timing possible to restore the appropriate light amount by the start of the next scan (t7).

If the return timing of the exposure lamp 12 is set at the above-mentioned predetermined time T from the end of the forward scan, even if the set copying magnification m changes variously and the timing at the end of the forward scan changes variously, the return timing can be reliably set. By the start of the next scan, the light 4 of the exposure lamp 12 will be maintained at the appropriate light m.

[Problem to be Solved by the Invention 1] By the way, it cannot be said that the peak power is sufficiently reduced in the conventional power-controlled IIl device that controls the light replenishment timing of the exposure lamp as described above. .

This is based on the following reasons.

In the case of the above example, the machine total power changes with the characteristics shown in FIG. That is, power consumption increases from the end of the return movement to the start of the next forward scan. From this, it has been experimentally shown that if the exposure lamp's light recovery timing is delayed and the light hang-down time is lengthened, the reduction in the total peak power of the machine will be greater, for example, as shown in Figure 7. . However, when the set copy magnification is low, the light intensity reduction time can be set longer (T2 in Fig. 7) and the amount of power reduction can be reduced to ΔP2. It is not possible to set the return timing based on the minimum light fall time (TI > in Figure 7) that is possible for high magnification (maximum reduction ΔP1). Therefore, assume the conditions for high copy magnification as described above. If the timing for restoring the light amount is determined based on the above, the power reduction that is originally possible is not often performed, especially at low magnification, and the peak power is not efficiently reduced.

This situation is not limited to copying machines in which the drive of the scanning system is controlled as described above, but the drive of the scanning system is controlled according to the set copying magnification, and the drive of the scanning system is started or This is common in copying machines in which timings such as drive stop are shifted depending on the set copying magnification.

In addition, as mentioned above, in the case of a type in which the exposure position on the RI4 material moves and high-speed control of the scanning system is performed especially at low magnifications, there is a relationship that keeps the exposure astringency per unit area on the photosensitive material constant. From this, the lower the magnification, the more the appropriate light intensity of the exposure lamp becomes (controlled. Specifically, for example, as shown by the solid line in FIG.
5), the exposure ml changes depending on the set copying magnification, but in order to compensate for this, the light amount of the exposure lamp is inversely controlled. From this point of view, in the case of the above-mentioned example, it is undesirable from the viewpoint of power reduction to have to make the optical return timing earlier than originally possible at low magnifications.

In addition, even in a general copying machine, the exposure amount of the photocopier changes as shown by the broken line in Figure 8 due to changes in the optical system due to zooming, but in this case as well, this can be compensated for. The same thing can be said if light tracking control of the exposure lamp is performed for this purpose.

SUMMARY OF THE INVENTION An object of the present invention is to achieve efficient power reduction when the exposure lamp moves back, regardless of the set copying magnification.

[1,000 Steps to Solve the Problem] The present invention provides a copying machine equipped with an exposure lamp 2 that irradiates light onto the original 1 by reciprocating relative to the original 1 according to a set copying magnification. In addition, a power control device was installed to control the exposure lamp 2 at a predetermined appropriate light level during the forward movement (G), and to reduce the light intensity of the exposure lamp 2 during the backward movement (B). 43. Technical means for solving the above problems in the power control device are as shown in FIG.
Set the timing for returning the exposure lamp 2 to the proper light level after reducing the optical loss during backward movement (B) according to the copying magnification (control l2I
The light amount return timing control means 3 is provided.

The optical article restoration control timing by the light amount restoration timing control means 3 is determined within a range that allows the proper light amount to be restored in time for the next forward scan at each set copy rate.

"Function" When the copying magnification is not set and the copying machine is started, the exposure lamp 2 and the document 1 perform relative reciprocation in the scanning range, speed profile, etc. according to the set copying magnification. (At Gl, the exposure lamp 2 is controlled at a predetermined appropriate light amount, and at the time of returning to work (8), the exposure lamp 2 is controlled at a predetermined appropriate light amount.
light intensity is reduced.

Then, the light h1 return timing control 3 returns the lowered light stone of the exposure lamp 2 to the proper light path at a timing corresponding to the set magnification.

[Example〕 Embodiments of the present invention will be described below based on the drawings.

FIG. 2 is a block diagram showing an example of the basic configuration of the power control device according to the present invention. It is assumed that the structure of the scanning system including the exposure lamp is similar to that shown in FIG.

In FIG. 2, 30 is a servo motor 22 for driving the scanning system.
It is a control arithmetic circuit that performs drive commands for the exposure lamp 12, light κ control of the exposure lamp 12, etc., and the light carrier return timing control means, which is a component of the present invention, is realized as a function of the n control circuit 30. 32 is a scanning system drive circuit that drives the C servo motor 22 in forward and reverse rotation corresponding to the reciprocating motion of the scanning system based on commands from the control calculation circuit 30. 36 is a registration sensor that detects the reference position for document scanning. The reference position detection signal 0/)<i11 from this registration sensor 36 is supplied to the control circuit 30 and the scanning system drive circuit 32. Furthermore, an encoder 24 is attached to the servo motor 22. A rotation signal from the encoder 24 accompanying the rotation of the servosetter 22 is input to the scanning system drive circuit 32. It is turned on and off based on commands from the controller, and its output is controlled.

Reference numeral 38 denotes a timing table C, in which the relationship between the set copy rate m and the return timing after the light b decreases is predetermined.

The specific details are: V D = 309m+/Sec (Photosensitive belt moving speed) K = 3.5 (PIS constant) C = 940a+sec (Cycle time) This cycle time C makes 63.8 copies per minute. I am assuming the case.

60000(ms)/63.84 940(+++s)
Under the scanning drive condition of V1m-V4n+, the relationship between the set copying magnification m and the time T from the fall of the scan end signal to the return of the light suspension is determined, for example, as shown by the solid line in FIG. ing.

That is, when (minimum magnification) 64%≦m<72%, T=8 4 5
-1 1 m (msec) 72%≦m≦155
% (highest magnification), T=62 (msec).

The relationship between the set copying magnification m and the time T until the light suspension returns is such that the latest timing at which the appropriate optical range is ensured before the next forward scan at each set copying magnification m is, for example, the third
As shown in the figure, the characteristic Qo (double-dashed line) is determined within a range that is less than the experimentally determined result.

Next, the operation will be specifically explained according to the timing chart shown in FIG. 6.

The operator sets the original on the platen 11 and sets the desired copy magnification m, for example, m = 100%.
%> information and a start signal g is input to the control circuit 30 (time 10). Then, the control calculation circuit 30 raises the scanning start signal and sends information on the copying magnification m to the scanning system drive circuit 32, and also raises the ON signal for the exposure lamp 12 (t1) and turns on the light in accordance with the set magnification. A control signal is sent to the power supply 34 for the exposure lamp 12. Based on the output signal from the control calculation circuit 30, the scanning drive circuit 32 drives the scanning servo motor 22 at a speed corresponding to the set copying magnification m (the speed of the exposure lamp 12 is v1Ill above),
The power supply 34 supplies power to the exposure lamp 12 according to the set copy rate m (for example, tube current 1.2 A).

As a result, forward scanning by the optical system is started with the exposure lamp 12 lit at an appropriate brightness, and document scanning is performed from the ON signal output timing (t2) from the registration sensor 36. The scan drive circuit 32 is a register sensor 36
The rotary pulse signal from the digital coder 24 is counted from the ON signal from the digital coder 24, and when the counted value reaches a value that corresponds to the scanning range determined by the set copying magnification, the scanning end signal is set.
Geru (t3). At this point, the actual scanning of the original is completed,
Scanning drive [11 path 32 performs brake control and reversal control for the scanning servo motor 22, and the optical system is about to shift to backward scanning. When the control arithmetic circuit 30 inputs the -L scan end signal, it lowers the scan start signal and outputs light;
Send reduced 611 Shinkyu to power source 34. In other words, a state in which the supply tube current to the exposure lamp 12 is reduced (for example, 0.
6^〉, the backward motion is performed, and in the process, the scanning system drive circuit 3
2 inputs the ON signal again from the registration sensor 36 (
At t4), a predetermined brake control is performed on the scanning servo motor 22, and then the scanning end signal is lowered to enter a state where the next scanning start signal is input. Control performance I
After the FII path 30 outputs the light intensity reduction control signal as described above, it waits for a time T (=62 m) corresponding to the set copying magnification m.
sec: m=100%> in timing table 38
from the falling timing (t5) of the scanning end signal from the scanning system drive circuit 32 to the corresponding time T
After 2113 (!C), a light spring control signal that provides an appropriate amount of light is sent to the power source 34 (t6) in preparation for the next document scan. Then, the exposure lamp 12 is supplied with power from the power supply 34 (tube current 1.2A with m=iooχ), and the register sensor 36 outputs at the next original exposure 1 cycle (r7).
By this time, the appropriate light level according to the set copying magnification is reached.

The set copy magnification or m is from the above 111 = 100% to m = 64
%, the time T for determining the optical loss recovery timing of the exposure lamp 12 is determined from the timing table 38 as T = 141 msec (845-11
x 64 ) is read out, and after 141 lIsec from the fall of the signal at the end of scanning as described above, the electric power (for example, 2.OA) that should provide the proper light intensity is supplied to the exposure lamp 12.

In the light control of the exposure lamp 12 as described above, the light of the exposure lamp 12 is set so that the time T from the fall of the scan end signal that determines the return timing is longer at lower copy magnifications. Even when the magnification is m (=64%), the decrease in the light amount of the exposure lamp 12 can be maintained until a later timing.

Therefore, peak power can be efficiently reduced at low copy magnification.

In the above embodiment, the exposure lamp 12 is
However, it is also possible to control the tube current when decreasing in accordance with the supply tube current to obtain the appropriate amount of light. In this case, the tube current at the time of decrease, which changes depending on the copying magnification, also becomes a factor that determines the timing of the return of the light h1.

Note that the present invention is not limited to the above-mentioned fixed original type copying machine, but can be similarly applied to a moving original type copying machine.

[Effects of the Invention] As described above, according to the present invention, the light return timing of the exposure lamp is controlled according to the set copying magnification, so that the exposure lamp does not return even at any copying magnification. More efficient power reduction can be achieved at times. As a result, the total erasure of the machine in the copier! The power consumption will be reduced and the power consumption of the copying machine will be reduced.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of the present invention, FIG. 2 is a diagram showing an example of the basic structure of the electric power system according to the present invention, and FIG. 3 is a diagram showing the set copying magnification and the light intensity return timing of the exposure lamp. 4 is a diagram showing an example of the structure of a scanning system in a copying machine. FIG. 5 is a diagram showing an example of the relationship between the reciprocating motion of the scanning system and power consumption. Figure 7 is a diagram showing the relationship between the light intensity reduction time and peak power reduction amount, and Figure 8 is a diagram showing the relationship between the copying magnification and the exposure amount on the photosensitive material. It is. [Explanation of symbols] 1... Documents 2, 12... Exposure lamp 3... Light amount return timing control means 22... Servo motor 24... Encoder 30... Control calculation circuit 32... Scanning System drive circuit 34...power supply 36...register sensor 38...timing table 1 diagram

Claims (1)

[Claims] A copying machine has a scanning exposure lamp (2) that irradiates light onto the surface of the original (1) by reciprocating relative to the original (1) according to the set copy magnification. At the time of G), the exposure lamp (2) is controlled at a predetermined appropriate amount of light, and during the backward movement (B
), the power control device is configured to reduce the light intensity of the exposure lamp (2) during backward movement (B), and the timing for returning the exposure lamp (2) to the appropriate light intensity after the light intensity reduction during backward movement (B) is set according to the copying magnification. A power control device for a copying machine, characterized in that it comprises a light amount return timing control means (3) for controlling.