JPH07199101A - Optical scanning device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a low-cost optical scanning device that simplifies or eliminates the positioning work of the synchronization detection sensor. [Structure] The laser light emitted from a light source unit 30 enters a rotary polygon mirror 12, and the laser light reflected by the rotary polygon mirror 12 is converted from a constant angular velocity to a constant velocity by an fθ lens 14, and a first mirror 15 Alternatively, it is incident on the second mirror 26. The laser light incident on the first mirror 15 is reflected by the photosensitive drum 1, and the laser light incident on the second mirror 26 has the same optical path as that at the time of emission because the reflecting surface is orthogonal to the optical axis. Return to the light source unit 30 with
A synchronization detection sensor (not shown) is arranged at 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical scanning device which is applied to an electrophotographic recording device and which scans a photosensitive member with laser light.

[0002]

2. Description of the Related Art FIG. 6 is a schematic configuration diagram of a laser printer which is an example of an electrophotographic recording device to which an optical scanning device is applied.

Reference numeral 1 is a photosensitive drum, 2 is a developing device, 3 is a charging device, 4 is a discharging lamp, 5 is a cleaning device, 6 is a transfer device, 7 is a paper feeding cassette, 8 is a fixing device, 9 is a control unit, 10 is an optical scanning device.

The charger 3 uniformly charges the photosensitive drum 1,
The optical scanning device 10 scans the photosensitive drum 1 with laser light corresponding to image information to form an electrostatic latent image on the photosensitive drum 1. The electrostatic latent image is developed into a toner image by the developing device 2, and the toner image is transferred by the transfer device 6 to the recording paper P that is synchronously conveyed from the paper feeding cassette 7, and then the recording paper P by the fixing device 8. Fixed on top. Also,
After the transfer is completed, the cleaning drum 5 removes and collects the residual toner on the photosensitive drum 1, and the charge eliminating lamp 4 neutralizes the charge.

FIG. 7 is a perspective view showing an example of a conventional optical scanning device.

Reference numeral 11 is a housing, 12 is a rotary polygon mirror, 13 is a light source unit fixed to the housing 11, 14 is an fθ lens, 15 is a first mirror, 16 is a second mirror, and 17 is a housing.
A synchronous detection sensor fixed to 11, and a polygon motor 18 supporting the rotary polygon mirror 12.

The control unit 9 outputs the image information and the light emission signal to the light source unit 13, and the light source unit 13 generates a laser beam corresponding to the image information when the light emission signal is input. The rotary polygon mirror 12, which rotates at a constant speed by the polygon motor 18,
It reflects the laser light emitted from the light source unit 13. The laser light reflected by the rotary polygon mirror 12 and moving at a constant angular velocity is incident on the fθ lens 14 and the moving speed is converted from the constant angular velocity to the constant velocity, and the first mirror 15 or the second mirror is moved.
Incident on 16.

The laser light incident on the first mirror 15 scans the photosensitive drum 1 at a constant speed to form an electrostatic latent image. The laser light incident on the second mirror 16 is reflected by the light receiving portion of the synchronization detection sensor 17 and detected by a photodiode (not shown) arranged inside the synchronization detection sensor 17.
The photodiode outputs a synchronization detection signal for controlling the output timing of the light emission signal and the rotation of the photosensitive drum 1 to the control unit 9.

[0009]

The synchronization detection sensor 17 as described above includes a circuit board and electronic parts such as a photodiode and an amplifier mounted on the circuit board, and is connected to the control section 9 via a harness 19. Connected. Also, the output time of the synchronization signal output from the synchronization detection sensor 17 is
It is a very short time of about several μsec to several tens of μsec, and therefore, the electrical noise from the harness 19 causes the control unit 9 to malfunction and drive the light source unit 13 or the photosensitive drum 1 at the wrong time. There is.

Further, in order to prevent the malfunction of the control unit 9 as described above, an optical fiber is mounted on the synchronization detection sensor 17,
It is also possible to connect this optical fiber to the control unit 9 and directly transmit the laser light to the control unit 9 as a synchronization detection signal. However, in this case, since the connector for connecting the optical fiber to the control unit 9 is expensive, the device cost is increased, and since the fiber diameter of the optical fiber is usually as thin as about 1 mm or less, the synchronization detection is performed. The light-receiving area of the sensor 17 also becomes smaller, so that the synchronization detection sensor 17 needs to be positioned with high accuracy, and the positioning and the reflection angle of the second mirror 17 also need to be adjusted with high accuracy.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical scanning device which can solve the above-mentioned problems by making positioning work of a synchronization detection sensor simple or unnecessary and also at low cost.

[0012]

In order to solve the above problems, a first means of the present invention is a laser diode package having a laser diode for generating a laser beam, and a light source mounted with the laser diode package. In the optical scanning device including a unit and a synchronization detection sensor that detects the laser light, the synchronization detection sensor is arranged in the light source unit.

Further, the second means is characterized in that the synchronization detection sensor is arranged inside the laser diode package.

Further, the third means is provided with a rotary polygon mirror for reflecting and deflecting the laser light, and the laser light is provided between the main reflecting surfaces for reflecting the laser light on the scanning surface in the rotary polygon mirror. It is characterized in that a sub-reflection surface that reflects light is formed.

[0015]

According to the above-mentioned first means, the optical scanning device is provided with the laser diode package having the laser diode, the light source unit equipped with the laser diode package, and the synchronous detection sensor for detecting the laser light. In, the light source unit and the synchronization detection sensor are configured as one unit by disposing the synchronization detection sensor in the light source unit.

Further, according to the second means, the laser diode package and the synchronization detection sensor are formed as one component by disposing the synchronization detection sensor inside the laser diode package, and the synchronization detection is performed with respect to the light source unit. The work of mounting and positioning the sensor is omitted.

Further, according to the third means, a rotary polygon mirror for reflecting and deflecting the laser light is provided, and the laser light source unit is provided between the main reflecting surfaces for reflecting the laser light on the scanning surface in the rotary polygon mirror. By forming the sub-reflecting surface that reflects the light, an independent optical component for feeding back the laser light to the synchronization detection sensor is unnecessary.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. In addition, in FIGS. 1 to 5, members corresponding to the members described based on FIGS. 6 and 7 are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 1 is a perspective view showing an embodiment of the optical scanning device of the present invention, and FIG. 2 is a structural view showing a light source unit in this embodiment.

Reference numeral 26 is a second mirror, and 30 is a light source unit. The reflection surface of the second mirror 26 is orthogonal to the optical axis of the laser light emitted from the fθ lens 14.

In the light source unit 30 shown in FIG. 2, 31 is a substrate, 32 is a laser diode package, and 33 is a laser diode built in the laser diode package 32. The laser diode package 32 is configured as one chip that supports a laser diode 32 and terminals for connecting the laser diode 32 to an external circuit. Further, 34 is a prism, 35 is a collimating lens, and 36 is a synchronization detection sensor composed of a photodiode or the like. Here, the substrate 31 is mounted with the laser diode package 32, the synchronization detection sensor 36, the prism 34, the collimator lens 35, and the synchronization detection sensor 36.
The laser diode package 32 and the synchronization detection sensor 36 are connected to the control unit 9 via a circuit (not shown) formed on the substrate 31 by printing or the like.

The laser light generated by the laser diode package 32 passes through the prism 34 and the collimator lens 35.
Is incident on the rotary polygon mirror 12 after being converted from divergent light into parallel light by the collimator lens 35.

The laser light reflected by the rotary polygon mirror 12 is converted from a constant angular velocity to a constant velocity by the fθ lens 14 and enters the first mirror 15 or the second mirror 26. The laser light incident on the first mirror 15 is reflected by the photosensitive drum 1, and the laser light incident on the second mirror 26 has the same optical path as that at the time of emission because the reflecting surface is orthogonal to the optical axis. Return to the light source unit 30 with.

In the light source unit 30, the prism 34 has a reflecting surface 34a which is inclined with respect to the returning laser light by a predetermined angle or more, and the reflecting surface 34a is configured to totally reflect the laser light due to the relation of the refractive index. There is. The laser light reflected by the prism 34 is incident on the light receiving portion of the synchronization detection sensor 36, and the synchronization detection sensor 36 detects the laser light and generates a synchronization detection signal.

As described above, by arranging the synchronization detecting sensor 36 in the light source unit 30, by mounting and positioning the light source unit 30, which is one unit, in the housing 11, the synchronization detecting sensor 36 is mounted and positioned at the same time. Since the work can be completed and the substrate 31 is made common, the number of parts can be reduced, so that the cost of the device can be reduced.

FIG. 3 is a block diagram showing another example of the light source unit in this embodiment.

Reference numeral 40 is a light source unit, and 41 is a laser diode package arranged in the light source unit 40. Inside the laser diode package 41, a synchronization detection sensor 36 and a hologram 42 which is an optical element having a deflection function are arranged.

The laser light generated by the laser diode 32 passes through the hologram 42 and enters the collimator lens 35. As described with reference to FIGS. 1 and 2, the laser light reflected by the second mirror 26 and returned to the light source unit 40 enters the hologram 42. At this time, the hologram 42 straightens the 0th-order diffracted light of the laser light and refracts the 1st-order diffracted light. This first-order diffracted light is a synchronous detection sensor 36
Then, the synchronization detection sensor 36 detects the laser beam and generates a synchronization detection signal.

By arranging the synchronization detection sensor 36 inside the laser diode package 41, the work of attaching and positioning the synchronization detection sensor 36 to the light source unit 40 becomes unnecessary, and the assembly and adjustment work of the apparatus can be simplified.

FIG. 4 is a plan view showing another example of the rotary polygon mirror in this embodiment.

The rotary polygon mirror 43 is formed with a plurality of main reflecting surfaces 43a for reflecting the laser beam and moving in the main scanning direction, and a sub-reflecting surface 43b arranged between each of the main reflecting surfaces 43a. Has been done. The rotary polygon mirror 43 reflects the laser light by the sub-reflection surface 43b at the timing when the movement of the laser light by the main reflection surface 43a is completed to the end of the scanning line. At this time, the sub-reflection surface 43b returns the laser light to the light source unit 30 at right angles to the optical axis of the laser light. This eliminates the need for the second mirror 26, so that the work of mounting and adjusting the second mirror 26 can be eliminated, and the device cost can be reduced.

FIG. 5 is a plan view showing another example of the main part of this embodiment.

By adjusting the angle of the second mirror 26 with respect to the incident laser beam as shown in the figure, the second mirror 26 can be adjusted.
Laser diode 32 in light source unit 50 by 26
It is possible to directly return the laser light to the synchronization detection sensor 36 located at a position different from. As a result, the light source unit 50
Since it is not necessary to provide an optical element such as the prism 34 for reflecting or deflecting the laser light, it is possible to further reduce the device cost.

[0034]

As described above, according to the first means of the present invention, the light source unit and the synchronization detecting sensor are configured as one unit, so that the light source unit is simply attached and positioned. At the same time, the mounting and positioning work of the synchronization detection sensor can be completed, which simplifies the assembly and adjustment work of the device, and the number of parts can be reduced by sharing the board etc., thus reducing the cost of the device. become.

Further, according to the second means, the laser diode package and the synchronization detection sensor are configured as one component, and the work of mounting and positioning the synchronization detection sensor with respect to the light source unit is omitted. It is not necessary to attach and position the synchronization detection sensor to the light source unit, and the assembly and adjustment work of the device can be simplified.

Further, according to the third means, since an independent optical component for feeding back the laser beam to the synchronization detection sensor is not required, it is possible to eliminate the work of mounting and adjusting one mirror, for example. In addition, the device cost can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an optical scanning device of the present invention.

FIG. 2 is a configuration diagram showing a light source unit in the present embodiment.

FIG. 3 is a configuration diagram showing another example of the light source unit in the present embodiment.

FIG. 4 is a plan view showing another example of the rotary polygon mirror in the present embodiment.

FIG. 5 is a plan view showing another example of the main part of the present embodiment.

FIG. 6 is a schematic configuration diagram of a laser printer which is an example of an electrophotographic recording device to which an optical scanning device is applied.

FIG. 7 is a perspective view showing an example of a conventional optical scanning device.

[Explanation of symbols]

9 ... Control unit, 12, 43 ... Rotating polygon mirror, 15 ... First mirror, 16, 26 ... Second mirror, 30, 40, 50 ... Light source unit, 31 ... Substrate, 32, 141 ... Laser diode package, 33 ... Laser diode, 34 ... Prism, 36
… Synchronous detection sensor, 42… Hologram, 43a… Main reflection surface, 43b… Sub reflection surface.

Claims (3)

[Claims] 1. An optical scanning device comprising a laser diode package having a laser diode for generating a laser beam, a light source unit having the laser diode package mounted thereon, and a synchronous detection sensor for detecting the laser beam, An optical scanning device in which the synchronization detection sensor is arranged in the light source unit. 2. The optical scanning device according to claim 1, wherein the synchronization detection sensor is arranged inside the laser diode package. 3. A rotary polygon mirror for reflecting and deflecting the laser light, wherein a sub-reflection surface for reflecting the laser light to the light source unit is provided between main reflection surfaces for reflecting the laser light on the scanning surface in the rotary polygon mirror. 2. The method according to claim 1, wherein
The optical scanning device described.