JP2994322B2 - Laser printer and laser printer control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a laser printer used as a printing machine or facsimile machine for a computer, or a copier, and a method of controlling the laser printer.

[0002]

2. Description of the Related Art A laser printer irradiates a laser beam to a photoreceptor, which is charged at a portion where light is incident, and attaches toner to the photoreceptor. Things.

FIG. 5 is a perspective view showing a configuration example of a laser optical unit of a conventional laser printer. The laser optical unit shown in this figure uses a scanner motor and a photo sensor.

In FIG. 5, a polygon mirror 102 having four reflecting surfaces reflects a laser beam output from a laser oscillator 103 while rotating by being driven by a polygon motor 101.

[0005] The laser beam reflected by the polygon mirror 102 is further reflected by the reflection mirror 105. Thus, the laser beam is scanned on the photoconductor 101.

[0006]

FIG. 6 is a diagram for explaining the timing of scanning of the laser beam in FIG.
On the path of the scanned laser beam, the reflection mirror 1
The photo sensor 104 installed next to the output unit 05 outputs a signal as shown in FIG. 6A every time a laser beam is incident. The output signal of the photo sensor 104 serves as a horizontal synchronizing signal, which is the output timing of the image data of the host controller.

In such a conventional example, even if the polygon motor 101 is rotating at a constant speed, the variation in the angle between the reflecting surfaces of the polygon mirror 102 causes a problem as shown in FIG.
As shown in (a), times t1, t2, t3 and t4 are not equal.

For this reason, the trajectories 110-1 to 100-4 of the laser beam scanned on the photoreceptor 106 are not at equal intervals, but vary at irregular intervals as shown in FIG. 6B. This variation also occurs due to uneven rotation of the photoconductor 106.

As described above, the variation of the laser beam caused by the shape of the polygon mirror 102 occurs even if the rotation of the polygon motor 101 is controlled to be constant. In addition, the rotation unevenness of the photoconductor 106 occurs due to vibration of a gear mechanism (not shown) for driving the photoconductor 106, and the like.
It was difficult to remove this completely.

The present invention has been made under such a background, and provides a laser printer and a control method of a laser printer capable of accurately scanning a beam at equal intervals and performing high-quality printing. The purpose is.

[0011]

In order to solve the above-mentioned problems, a laser printer according to the first aspect of the present invention is provided.
A photoreceptor (6) having a cylindrical shape and rotating in the circumferential direction;
A beam for charging a predetermined portion of the surface of the photoreceptor is formed.
Beam generating means (3) for generating the reflected light;
The reflecting means (5) for producing light and the beam exciting means.
Polygon mirror for scanning a beam in the axial direction of the photoconductor
(2) and angle adjustment for adjusting the reflection angle of the reflection means
Means (7); and running of said beam adjacent said reflecting means.
A beam detecting means (4) provided on the scanning line;
Scanning of the beam based on the output signal of the
Determination means (9) for determining return timing
And the angle adjusting means determines the result of the determination by the determining means.
Adjusting the reflection angle of the reflection means based on the
Correcting the scanning position of the beam on the outer peripheral surface of the laser beam
It is characterized by. The laser pudding according to claim 2 of the present invention.
2. The scanning timing of the beam according to claim 1,
Pulse generating means for generating a reference pulse to be used as a reference
(8), wherein the determination means is configured to determine whether the reference pulse is
Based on the timing difference with the output signal of the beam detector
Controlling the angle adjusting means so that the outer peripheral surface of the photosensitive member is
And correcting the scanning position of the beam.
You. According to a third aspect of the present invention, there is provided a laser printer.
Item 3. A polygon model for driving the polygon mirror according to item 2.
Data (1), wherein the reference pulse generating means is
Before the rotation of the polygon motor stabilizes at the specified speed
Generating the reference pulse. A laser printer according to a fourth aspect of the present invention has a cylindrical shape and a circumferential shape.
Photoreceptor (6) rotating in the direction, and a location on the surface of the photoreceptor
Beam excitation to generate a beam to charge a fixed part
Means (3) and reflecting means (5) for reflecting said beam
The beam output by the beam excitation means to the photosensitive member
A polygon mirror (2) that scans in the axial direction of the
An angle adjusting means (7) for adjusting a reflection angle of the means;
Provided on the scanning line of the beam adjacent to the reflecting means
Beam detection means (4), and rotation timing of the photoconductor
Comprising a rotation detecting means (11) for detecting a pre-Symbol photoreceptor
In the part of the axial direction of the
Timing information is formed, and the rotation detecting means
The reading information, and the determination means
Output signal of the rotation detection means and output signal of the beam detection means
Control the angle adjusting means based on the timing difference
Scanning position of the beam on the outer peripheral surface of the photoconductor
Is corrected. A laser printer according to a fifth aspect of the present invention is the laser printer according to any one of the first to fourth aspects.
The angle adjusting means described in the above, in the reflecting means,
Attached on the side substantially parallel to the scanning line of the beam,
A side substantially parallel to the scanning line of the beam in the reflecting means
Characterized in that the side opposite to is rotatably supported.
You. A laser printer according to claim 6 of the present invention
The angle adjusting means according to any one of claims 1 to 4.
Is substantially parallel to the scanning line of the beam in the reflection means.
The reflecting means, and
The side opposite to the side substantially parallel to the scanning line is elastically supported.
It is characterized by being performed. The laser according to claim 7 of the present invention.
The control method of the printer is as follows.
It forms a cylindrical shape through the mirror and the reflection means and
Part of the beam scanned in the axial direction of the rotating photoreceptor
Detection by the
Seeking the imaging, the determining means, the timing of the scanning,
Tie with the reference pulse generated by the reference pulse generation means
Controlling the angle adjusting means based on the difference in
Adjusting the reflection angle of the light emitting means on the outer peripheral surface of the photoreceptor
The scanning position of the beam is corrected .
A method for controlling a laser printer according to claim 8 of the present invention.
Separates the polygon mirror and the reflection means from the beam excitation means.
Axial direction of the photoreceptor that rotates in the circumferential direction through a cylindrical shape
Part of the beam scanned in the direction
The timing of the scan is determined by detecting
It is formed on a part of the photoconductor in the axial direction by the detecting means.
Read timing information at equal intervals in the circumferential direction of the photoconductor
The rotation timing of the photoconductor is detected by the
Disconnecting means for outputting the output signal of the rotation detecting means and the scanning timing;
Controlling the angle adjusting means based on the difference from the
The scanning position of the beam on the outer peripheral surface of the photoconductor.
It is characterized by correction.

[0012]

DETAILED DESCRIPTION OF THE INVENTION First Embodiment The present invention will be described below. FIG. 1 shows a first embodiment of the present invention.
FIG. 1 is a configuration diagram illustrating a configuration of a laser printer according to an embodiment. In FIG. 1, a laser oscillator 3 outputs a laser beam toward a polygon mirror 2 which is driven by a polygon motor 1 and rotates.

The laser beam reflected by the polygon mirror 2 is further reflected by the reflection mirror 5 and scans the photosensitive member 1 rotating at a constant speed. The photosensor 4 on the above-described laser beam scanning path is provided at a position where the laser beam crosses immediately before the laser beam starts scanning the photosensitive member 1, and outputs a signal when the laser beam passes.

The polygon motor 1 sends a signal to the reference pulse generator 8 when the rotation speed reaches the specified rotation speed. Upon receiving the signal, the reference pulse generator 8 outputs a pulse signal at equal intervals calculated from the signal of the photo sensor 4. Output.

The judging circuit 9 compares the signal of the reference pulse generator 8 with the signal of the photo sensor 4 and outputs a drive signal corresponding to a correction amount obtained from the time difference to the piezo element 7 for operation.

The piezo element 7 is mounted on one side of the reflection mirror 5 substantially parallel to the scanning line of the laser beam, and the side opposite to this side is rotatably mounted. As a result, the piezo element 7 changes the angle of the reflection mirror 5 and corrects the position of the laser beam output from the laser oscillator 3 and scanned by the photoconductor 6.

FIG. 2 is a diagram for explaining the timing of laser beam scanning in the present embodiment. In FIG. 1, a polygon mirror 2 having four reflecting surfaces is a polygon motor 1
, And reflects the laser beam output from the laser oscillator 3. The laser beam reflected by the polygon mirror 2 is further reflected by the reflection mirror 5 and scans the photoconductor 1.

On the path of the laser beam scanned in this way, the photo sensor 4 provided adjacent to the reflection mirror 5 sends the reference pulse generator 8 and the judgment circuit 9 each time the laser beam passes. A signal as shown in FIG.

As shown in FIG. 2A, even if the polygon motor 1 is rotating at a constant speed, the times t1, t2, t
3 and t4 are not equal to each other. This is due to a variation in the angle between the reflection surfaces of the polygon mirror 2.

The polygon motor 1 sends a signal to the reference pulse generator 8 when the rotation speed reaches a specified rotation speed and the rotation speed becomes constant. When receiving the signal from the polygon motor 1, the reference pulse generator 8 starts counting pulse signals output from the photosensor 4.

That is, assuming that the number of pulses equal to the number of surfaces of the polygon mirror 2 (4 in the present embodiment) is one cycle T, as shown in FIG. A pulse signal having a period of / 4 is output to the judgment circuit 9.

At this time, the reference pulse generator 8 resynchronizes the pulse signal output from the photosensor 4 every one cycle or every several cycles. Thereby, the error between the signal output timing and the scanning timing of the laser beam is integrated, and the trajectories 10, 10.
・ Correct the misalignment like.

The laser beam is scanned on the photosensitive member 6 rotating at a constant speed. If the scanning timing of the laser beam varies, the interval between the trajectories of the laser beam on the photosensitive member 6 also varies.

The judgment circuit 9 compares the signal output from the photo sensor 4 with the signal output from the reference pulse generator 8,
A variation in the timing at which the laser beam crosses the photosensor 4 is detected.

Then, the angle of the reflection mirror 5 is calculated so that the interval between the scanning lines (trajectories) on the photosensitive member 6 is constant.
FIG. 3 is a side view showing a positional relationship among the polygon mirror 2, the reflection mirror 5, the piezo element 7, and the photoconductor 6.

In this embodiment, the angle of the reflection mirror 5 is changed by driving the piezo element 7 as shown in FIG.
By changing the angle of the reflection mirror 5, the laser beam is corrected to a correct position on the photoconductor 6.

B. Second Embodiment FIG. 4 is a configuration diagram showing a configuration of a laser printer according to a second embodiment of the present invention. In FIG. 4, the same reference numerals are given to portions corresponding to the respective portions shown in FIG. 1 or FIG.

In the configuration shown in FIG. 4, pulse-like magnetic information is arranged at predetermined regular intervals on the outer peripheral surface of a part of the photosensitive member 6, and a signal based on the magnetic information is provided at a position facing the magnetic information. Is provided. The output signal of the magnetic head 11 is input to the judgment circuit 9.

Since the magnetic information formed on the photoconductor 6 is arranged at equal intervals, the number of pulses output by the magnetic head 11 per unit time is proportional to the rotation amount of the photoconductor 6. The determination circuit 9 compares the signal output from the photosensor 4 with the signal output from the reference pulse generator 8 to detect a variation in the timing at which the laser beam crosses the photosensor 4.

The judgment circuit 9 further includes a reference pulse generator 8
The number of pulses output from the magnetic head 11 is counted during the period from the input of one pulse to the next pulse, and the variation of the rotation amount of the photoconductor 6 is calculated. To detect.

The judging circuit 9 calculates the angle of the reflection mirror 5 at which the interval between the scanning lines on the photoconductor 6 is constant, based on the above-mentioned fluctuation of the timing of the laser beam and the fluctuation of the rotation amount of the photoconductor 6. .

The piezo element 7 is driven (see FIG. 3) based on the value calculated by the determination circuit 9, and the angle of the reflection mirror 5 is changed. By changing the angle of the reflection mirror 5 in this manner, the laser beam is scanned at a correct position on the photoconductor 6.

The method of controlling a laser printer according to each of the above-described embodiments generally uses a random access memory (RAM) or a read only memory (ROM) provided in the laser printer body. ) Or a flash memory or the like, but may be a magnetic disk such as a hard disk or a magneto-optical disk or a storage medium such as an optical disk provided in a computer that supplies data to the laser printer. Further, the data may be written in these storage media by communication means such as a telephone line.

[0034]

As described above, according to the present invention, scanning is performed in the axial direction of the photosensitive member which is cylindrical and rotates in the circumferential direction from the beam exciting means via the polygon mirror and the reflecting means. The scanning timing is obtained by detecting a part of the beam by the beam detecting means, and the judging means controls the angle adjusting means based on the scanning timing to adjust the reflection angle of the reflecting means to scan the photosensitive member. Correct the circumferential spacing between the beams. The determining means controls the angle adjusting means based on the timing difference between the reference pulse generated by the reference pulse generating means and the output signal of the beam detecting means to correct the beam scanning position on the outer peripheral surface of the photoconductor. The rotation detection unit detects rotation timing of the photoconductor by reading timing information formed at a part in the axial direction of the photoconductor and arranged at equal intervals in a circumferential direction of the photoconductor. The angle adjustment means is controlled based on the timing difference between the signal and the output signal of the beam detection means to correct the scanning position of the beam on the outer peripheral surface of the photoreceptor. An advantage is obtained that a laser printer capable of printing and a control method of the laser printer can be realized.

That is, in the present invention, the process of correcting the scanning position of the laser beam is performed by detecting the variation in the scanning timing of the laser beam by comparing the signal of the photosensor and the signal of the reference pulse generator. That is,
By eliminating the influence of the scanning accuracy of the polygon mirror on the scanning position of the laser beam, a high-quality image is obtained.

In the present invention, a high-quality image can be obtained by eliminating the influence of uneven rotation of the photosensitive member. this is,
This is because a process of correcting the scanning position of the laser beam by measuring the rotation amount of the photoconductor per unit time is performed.

The same operation and effect can be obtained by replacing the combination of the piezo element and the reflecting mirror described in each of the above embodiments with a prism formed of a variable refractive index glass whose refractive index changes with a voltage. Is obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a configuration of a laser printer according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating timing of scanning with a laser beam in the embodiment.

FIG. 3 is a side view showing a positional relationship among a polygon mirror 2, a reflection mirror 5, a piezo element 7, and a photoconductor 6 in the embodiment.

FIG. 4 is a configuration diagram illustrating a configuration of a laser printer according to a second embodiment of the present invention.

FIG. 5 is a perspective view showing a configuration example of a laser optical unit of a conventional laser printer.

FIG. 6 is a diagram for explaining the timing of laser beam scanning in FIG. 5;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 polygon motor 2 polygon mirror 3 laser oscillator (beam excitation means) 4 photosensor (beam detection means) 5 reflection mirror (reflection means) 6 photoreceptor 7 piezo element (angle adjustment means) 8 reference pulse generator (reference pulse generation means) 9) Judgment circuit (judgment means) 10, 10 ... locus 11 Magnetic head (rotation detection means) 101 Polygon motor 102 Polygon mirror 103 Laser oscillator 104 Photosensor 105 Reflection mirror 106 Photoconductor 107 Piezo element 108 Reference pulse generator 109 Judgment circuit 110-1 to 110-4 locus

Claims (8)

(57) [Claims] 1. A photosensitive member having a cylindrical shape and rotating in a circumferential direction.
A body (6) and a beam for charging a predetermined portion of the surface of the photoconductor
(3), a reflecting means (5) for reflecting the beam, and an axis of the photoreceptor for outputting the beam output from the beam exciting means.
A polygon mirror (2) for scanning in a direction, and an angle adjusting means (7) for adjusting a reflection angle of the reflecting means.
When, et disposed adjacent to the reflection means on a scanning line of the beam
Based on the detected beam detection means (4) and the output signal of the beam detection means.
Judging means (9) for judging the repetition timing of scanning
If, comprising a, the angle adjusting means based on the determination result by the determination unit
To adjust the reflection angle of the reflection means, and
Correcting the scanning position of the beam on the peripheral surface.
Laser printer. 2. A reference for a timing of scanning the beam.
A reference pulse generating means (8) for generating a reference pulse
The determination means includes the reference pulse and the beam detection means.
The angle adjusting means based on the timing difference with the output signal of
Controlling the stage to compensate for the scanning position of the beam on the outer peripheral surface of the photoconductor.
2. The laser printer according to claim 1, wherein the correction is performed. 3. A polygon for driving said polygon mirror.
A motor (1), wherein the reference pulse generating means is configured to rotate the polygon motor
Generates the above-mentioned reference pulse after it is stabilized at a predetermined rotation speed.
That, laser printer according to claim 2, characterized in that. 4. A photosensitive member having a cylindrical shape and rotating in a circumferential direction.
A body (6) and a beam for charging a predetermined portion of the surface of the photoconductor
And generating a beam exciting means (3), and the reflection means (5) for reflecting the beam, a beam said beam excitation means outputs of the photosensitive body shafts
A polygon mirror (2) for scanning in a direction, and an angle adjusting means (7) for adjusting a reflection angle of the reflecting means.
When, et disposed adjacent to the reflection means on a scanning line of the beam
Beam detection means (4), and rotation detection means for detecting the rotation timing of the photoconductor
(11), wherein a part of the photoconductor in the axial direction is provided in the circumferential direction of the photoconductor.
When timing information of the interval is formed, and the rotation detecting means reads the timing information,
In addition, the judging means includes an output signal of the rotation detecting means and the
Based on the timing difference with the output signal of the
Controlling the angle adjusting means to compensate for the scanning position of the beam on the outer peripheral surface of the photoconductor.
Positive to, a laser printer, characterized in that. 5. An apparatus according to claim 1, wherein said angle adjusting means is provided in said reflecting means.
To the side substantially parallel to the scanning line of the beam.
Is, substantially parallel to the scanning lines of said beam at said reflective means
The side opposite to the side is rotatably supported, and is defined by any one of claims 1 to 4.
On-board laser printer. 6. An apparatus according to claim 1, wherein said angle adjusting means is provided in said reflecting means.
To the side substantially parallel to the scanning line of the beam.
Is, substantially parallel to the scanning lines of said beam at said reflective means
The side opposite to the side is elastically supported, according to any one of claims 1 to 4, characterized in that:
On-board laser printer. 7. A system according to claim 7, wherein said beam exciting means is opposed to said polygon mirror.
A sense of rotating in the circumferential direction with a cylindrical shape through the shooting means
A part of the beam scanned in the axial direction of the light
The timing of the scan is determined by detecting
The determining and determining means determines the timing of the scanning and the generation of the reference pulse.
Based on the timing difference from the reference pulse generated by the generator
Controlling the angle adjusting means to adjust the reflection angle of the reflecting means to adjust the outer peripheral surface of the photoreceptor.
The scanning position of the beam to correct the control method of the laser printer, characterized in that in the. 8. A method according to claim 1, wherein said beam exciting means is opposed to said polygon mirror.
A sense of rotating in the circumferential direction with a cylindrical shape through the shooting means
A part of the beam scanned in the axial direction of the light
The timing of the scan is determined by detecting
And formed on a part of the photoreceptor in the axial direction by rotation detection means
And read timing information at equal intervals in the circumferential direction of the photoconductor.
It detects the rotation timing of the photosensitive body by taking seen, the determining means, the run output signal of the rotation detecting means
The angle adjusting means based on the difference from the inspection timing.
Controlling the scanning of the beam on the outer peripheral surface of the photoconductor
A method for controlling a laser printer , comprising correcting a position .