JPH0580642A - Image write device - Google Patents

Abstract

PURPOSE:To reduce power consumption, generated heat and the production of noise, to prolong the life of a scanner motor and to shorten waiting time from stopping the write of an image till starting recording. CONSTITUTION:In the case of the standby time, a CPU 10 selects an oscillator 41 so that the scanner motor 53 may be rotated at high speed for the set time T1, selects an oscillator 42 so that the scanner motor 53 is rotated at middle speed until the set time T2 elapses after the lapse of the set time T1, and selects an oscillator 43 so that the scanner motor 53 may be rotated at low speed after the lapse of the set time T2. Then, the CPU 10 changes the set time T1 at the time of rotating at high speed and the set time T2 at the time of rotating at middle speed in accordance with copying frequency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image writing device for writing an image by rotating a scanner motor to scan a laser beam.

[0002]

2. Description of the Related Art Heretofore, an image writing apparatus of this type has a scanner motor for rotating a rotary polygon mirror for deflecting a laser beam, which is provided at a predetermined time when an image is written, as disclosed in Japanese Patent Laid-Open No. 59-9624. By rotating at high speed at rotation speed and at low speed at, for example, 1/2 rotation speed on average during image writing pause, power consumption, heat generation and noise are reduced, and the life of the scanner motor is extended. Is configured.

[0003]

However, in the above-mentioned conventional image writing apparatus, since the scanner motor is rotated at a low speed in one stage when the image writing is stopped, when the number of rotations is set low, the image writing is started. At times, it takes time for the number of rotations of the scanner motor to reach the rated number of rotations, resulting in a long start-up time of the scanner motor and a long waiting time before the start of writing. On the other hand, when the number of rotations is set high, it is not possible to reduce power consumption, heat generation, noise, or extend the life of the scanner motor.

In view of the above-mentioned conventional problems, the present invention can reduce power consumption, heat generation and noise, extend the life of the scanner motor, and wait from the time of image writing suspension to the start of writing. It is an object of the present invention to provide an image writing device that can reduce the time.

[0005]

In order to achieve the above object, the first means is a scanner motor, a polygon mirror rotatably driven by the scanner motor, and a laser beam generating means for emitting a laser beam to the polygon mirror. ,
In an image writing device having a photoconductor that is irradiated with a laser beam that is reflected by a polygon mirror and is scanned to form a latent image, the scanner motor rotates at a predetermined rotational speed at high speed during image writing, The present invention is characterized in that a rotation control means for the scanner motor is provided for controlling to gradually rotate at a low speed at a plurality of rotation speeds lower than the rotation speed at each set time during the writing suspension.

The second means sets the respective set times for the rotation control means of the first means to lower the number of rotations to be long when the image writing frequency is high and to set them short when the image writing frequency is low. It is characterized by

[0007]

According to the first means, the scanner motor is gradually rotated at a low speed with a plurality of rotation speeds at each set time when the image writing is stopped, so that the image writing is stopped when the image writing frequency is high. The waiting time from time to the start of writing can be shortened, power consumption, heat generation and noise can be reduced when the image writing frequency is low, and the life of the scanner motor can be extended.

In the second means, when the frequency of image writing is high, each set time for lowering the number of rotations is set long, so that the time for switching to low speed rotation becomes long, and therefore, from the time of image writing suspension. The waiting time until the start of writing can be further shortened. Further, when the image writing frequency is low, each set time for lowering the rotation speed is set to be short, so that the time for switching to the low speed rotation is shortened, thus further reducing power consumption, heat generation and noise, and The life of the scanner motor can be extended.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a block diagram showing the essential parts of an embodiment of the image writing device according to the present invention, FIG. 2 is a block diagram showing the essential parts of the motor driver of FIG. 1, and FIG. 3 is the image writing device of FIG. 4 is a timing chart for explaining the schematic operation, FIG. 4 is a flowchart for explaining the operation of the main routine of the image writing apparatus of FIG. 1, and FIG. 5 is a detailed operation of the first rotation speed setting routine of FIG. 6 is a flowchart for explaining the detailed operation of the second rotation speed setting routine of FIG. 4, and FIG. 7 is a detailed operation of the third rotation speed setting routine of FIG. 8 is a flow chart for explaining the detailed operation of the software timer routine of FIG. 4, and FIG. 9 is a flow chart for explaining the detailed operation of the set time setting routine during high speed rotation of FIG. DOO, FIG. 10 is a flowchart for explaining the detailed operation of the set routine of setting time at medium speed rotation of FIG.

In FIG. 1, a CPU (central processing unit) 1
0 controls the entire digital copying machine. Particularly, as will be described later, the scanner motor 53 is rotated at a high speed at a predetermined rotation speed during image writing via an I / O (input / output) port 11 to write an image. At rest, control is performed such that the rotation speed is gradually reduced at a plurality of rotation speeds lower than the rotation speed at each set time. This CPU 10 has port 4 of I / O port 11
The operation signal of the start key 12 is input via
From this CPU 10, ports 1 to 1 of the I / O port 11
The selection signals for the recording high-speed mode, the standby medium-speed mode, and the low-speed mode are output to selectors (illustrated AND gates) 31, 32, and 33 via 3, respectively.
When this image writing device is used in a copying machine, the start key 12 is a copy star key, and therefore the copy frequency can be detected by the operation frequency of this key.

The oscillator (OSC1) 41 is configured to generate a reference clock for the scanner motor 53, which rotates a polygon mirror 54, which will be described later, to rotate at a high speed (rotation speed r1) during writing and output the reference clock to the selector 31. The oscillator (OSC2) 42 is configured to generate a reference clock for rotating the scanner motor 53 at a medium speed {rotation speed r2 (<r1)} during standby, and output the reference clock to the selector 32. ) 43, the scanner motor 53 is configured to generate a low speed {rotational speed r3 (<r2 <r1)} reference clock and output it to the selector 33 during standby. The reference clock selected by the selectors 31 to 33 is output as a clock to the driver 52 of the scanner motor 53 via the OR gate 51, and the scanner motor 53 rotates at a speed corresponding to the reference clock to rotate the polygon mirror. 54 is rotated.

A laser diode (LD) 55 emits a laser beam corresponding to a written image, and the laser beam is deflected by the reflecting surface of the polygon mirror 54 at an equal angle.
It is corrected by the f-θ lens 56 so as to be deflected at a constant speed on the photoconductor 57. An electrostatic latent image corresponding to the written image is formed on the photoconductor 57 by the laser light, and the electrostatic latent image is developed by a known electrophotographic process such as charging, exposure, development, transfer and fixing. Then, a toner image is recorded on the sheet.

In the motor driver 52 shown in FIG. 2, the comparator 52a compares the selected reference clock with each phase of the pulse signal output from the tacho generator 53a (or encoder) of the scanner motor 53, and drives the driving circuit. 52b controls the drive current of the scanner motor 53 so that the phase difference becomes "0". Therefore, the scanner motor 53 and the polygon mirror 54 rotate at a rotation speed proportional to the frequency of the selected reference clock.

Next, the operation of the above embodiment, particularly the operation of the CPU 10 will be described with reference to FIGS. First, the schematic operation will be described with reference to FIG. 3. After the power is turned on and until a predetermined set time T1 elapses after the recording operation is completed, the scanner motor 53 is at a high speed (rotation speed r1) even in the standby state.
The oscillator 41 is selected to rotate at. Then, in the standby state, after the set time T1 has elapsed, the oscillator 42 is selected so that the scanner motor 53 rotates at a medium speed (rotation speed r2) until the predetermined set time T2 elapses. After the lapse of time, the oscillator 43 is selected so that the scanner motor 53 rotates at a low speed (rotation speed r3). The set time T1 for the high speed rotation of the rotation speed r1 and the set time T2 for the medium speed rotation of the rotation speed r2 are changed according to the recording frequency as described later.

In FIG. 4, when the copying operation (in the case of a copying machine) is completed (step S1), the first rotation speed setting routine is executed as shown in detail in FIG. 5 (step S2). In this routine, the high speed reference clock of the oscillator 41 is selected by turning on the output port 1 of the I / O port (step S2-1), and the output ports 2 and 3 are turned off (step S2-2). ), Then FIG.
Proceed to step 3 shown in, and the set time T1 for the high-speed rotation is set.
Both the counter T1 and the counter T1a for counting the operation interval of the start key 12 at the set time T1 are reset to “0”.

When the start key 12 is pressed (step S4), the counter T as shown in detail in FIG.
The set routine of the set time of 1 is executed (step S
5) and returns to step S2. In FIG. 9, the counter T
If 1a is less than the set value a, the set time of the counter T1 is set to the set value b (steps S5-1 and S5-
2) If the counter T1a exceeds the set value a, the set time of the counter T1 is set to the set value c (<b) (steps S5-1 and S5-3). Then, the counter T1a is cleared (step S5-4).

If it is decided at step S4 that the start key 12 is not depressed, then the processing advances to step S6,
The counters T1 and T1a are both incremented by one, and then a software timer routine as shown in detail in FIG. 8 is executed (step S7). In this software timer routine, first, timer A is cleared (step S7-1), then timer A is incremented by one (step S7-3), and when this timer A exceeds the set value (step S7-). 3), the process proceeds to step S8 shown in FIG.

Then, it is judged whether or not the counter T1 exceeds the above-mentioned set time b or c, and if it does not exceed the set time b or c, the process returns from step S8 to step S4, and if it exceeds, the process proceeds from step S8 to step S9. Then, the counter T1 is cleared (step S9), and then a second rotation speed setting routine as shown in detail in FIG. 6 is executed (step 10). In this second rotation speed setting routine, the port 2 is turned on (step S10-
1), oscillator 42 by turning off ports 1 and 3
The middle-speed reference clock is selected (step S10-
2).

That is, when the copy key 12 is frequently operated and the copy frequency is high, the set time of the counter T1 is set to a long time b, and when the copy frequency is low, the set time of the counter T1 is short time c. The counter T1 is set to the setting time b or c depending on the copy frequency.
When it exceeds, the scanner motor 53 rotates at a medium speed.

In a succeeding step S11, a counter for the set time T2 of the medium speed rotation and a counter T1a for counting the operation interval of the start key 12 at the set time T2.
Are both reset to "0". Similarly, when the start key 12 is pressed (step S12), a setting routine of the set time of the counter T2 as shown in detail in FIG. 10 is executed (step S13), and the process returns to step S2. In FIG. 10, when the counter T2a is less than the set value d, the set time of the counter T1 is set to the set value e (steps S13-1, S13-2), and the counter T2a exceeds the set value d. In this case, the set time of the counter T2 is set to the set value f (<e) (step S13-1,
S13-3). Then, the counter T2a is cleared (step S13-4).

If it is decided at step S12 that the start key 12 is not pressed, then the processing advances to step S14, at which counters T2 and T2a are both incremented by one, and then the above-mentioned software timer routine (FIG. 8) is executed. Yes (step S15). Then, in step S16, it is determined whether or not the counter T2 exceeds the above-described set time e or f. If not, the process returns from step S16 to step S12, and if it exceeds, the process proceeds from step S16 to step S17. And the counter T
2 is cleared (step S17).

Then, a third rotational speed setting routine as shown in detail in FIG. 7 is executed (step 18). In addition,
In the third rotation speed setting routine, the low speed reference clock of the oscillator 43 is selected by turning on the port 3 (step S18-1) and turning off the ports 1 and 2 (step S18-2). This low speed rotation is continued unless the start key 12 is pressed (step S1
8, S19), when the start key 12 is pressed, the process returns to step S2 to perform high speed rotation.

Therefore, also in this case, when the copy key 12 is frequently operated and the copy frequency is high, the setting time of the counter T2 is set to a long time e, and when the copy frequency is low, the setting of the counter T2 is set. The time is set to a short time f, and when the counter T2 exceeds the set time b or c corresponding to the copy frequency, the scanner motor 5
3 rotates at low speed.

As described above, according to the above-described embodiment, the scanner motor 53 sets the set times T1 and T2 when the image writing is stopped.
Since the rotation speed is gradually reduced every time, the waiting time from the image writing pause to the writing start can be shortened when the image writing frequency is high, and the power consumption and the power consumption can be reduced when the image writing frequency is low. Heat generation and noise are reduced, and the scanner motor 53
The life of can be extended.

Further, when the copying frequency is high, the set times T1 and T2 for shifting from the high speed rotation to the medium speed rotation and from the medium speed rotation to the low speed rotation are set short, so that the writing is started from the time when the image writing is stopped. The waiting time until the start can be further shortened. Furthermore, when the frequency of copying is low, the set times T1 and T2 for shifting from high speed rotation to medium speed rotation and from medium speed rotation to low speed rotation are set longer, so that power consumption, heat generation and noise are further reduced, Also, the scanner motor 53
The life of can be further extended.

In the above embodiment, the scanner motor 5
It was configured to control the rotation speed of 3 in 3 steps.
The number of stages may be more than one, and the set times T1 and T2 may be set to 2
Although the control is performed in stages, it may be performed in three or more stages.

[0027]

As described above, according to the first aspect of the present invention, the scanner motor rotates at a high speed at a predetermined rotation speed during image writing, and when the image writing is stopped, the rotation speed is higher than the predetermined rotation speed. Since the control means for controlling the rotation speed to gradually rotate at a low number of stages is provided, it is possible to shorten the waiting time from the image writing suspension to the writing start when the image writing frequency is high. Further, when the frequency of image writing is low, power consumption, heat generation, and noise can be reduced, and the life of the scanner motor can be extended.

According to a second aspect of the present invention, the control means according to the first aspect sets each set time for lowering the number of revolutions longer when the image writing frequency is high, and shorter when the image writing frequency is low. Therefore, when the image writing frequency is high, each set time for lowering the rotation speed is set long, and therefore, the time for switching to the low speed rotation becomes long, so that the waiting time from when the image writing is stopped to when the writing is started. Can be further shortened. Further, when the image writing frequency is low, each set time for lowering the rotation speed is set to be short, so that the time for switching to low speed rotation is shortened, thus further reducing power consumption, heat generation and noise generation, Moreover, the life of the scanner motor can be further extended.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of an image writing apparatus according to the present invention.

FIG. 2 is a block diagram showing a main part of the motor driver of FIG.

FIG. 3 is a timing chart for explaining a schematic operation of the image writing device shown in FIG.

FIG. 4 is a flowchart for explaining the operation of a main routine of the image writing device in FIG.

5 is a flow chart for explaining a detailed operation of a first rotation speed setting routine of FIG.

6 is a flow chart for explaining a detailed operation of a second rotation speed setting routine of FIG.

FIG. 7 is a flowchart for explaining detailed operation of a third rotation speed setting routine of FIG.

FIG. 8 is a flowchart for explaining detailed operation of the software timer routine of FIG.

9 is a flowchart for explaining detailed operation of a setting routine for setting time during high speed rotation in FIG.

FIG. 10 is a flowchart for explaining detailed operation of a setting routine for setting time during medium speed rotation in FIG.

[Explanation of symbols]

 10 CPU (Central Processing Unit) 12 Copy Mode Key 31, 32, 33 Selector 41, 42, 43 Oscillator 52 Motor Driver 53 Scanner Motor 54 Polygon Mirror 55 Laser Diode

Claims (2)

[Claims] 1. A scanner motor, a polygon mirror rotatably driven by the scanner motor, a laser beam generating means for emitting a laser beam to the polygon mirror, and an irradiation of a laser beam reflected and scanned by the polygon mirror. An image writing apparatus having a photosensitive member for forming a latent image, wherein the scanner motor is rotated at a high speed at a predetermined rotation speed during image writing, and a plurality of steps lower than the rotation speed are set at each set time when the image writing is stopped. An image writing apparatus, comprising: a rotation control unit of a scanner motor that controls the rotation speed to gradually rotate at a low speed. 2. The rotation control means sets each set time for lowering the rotation number long when the image writing frequency is high, and sets it short when the image writing frequency is low. 1. The image writing device according to 1.