JPS6059863A - Optical system controller of laser beam printer - Google Patents

Abstract

PURPOSE:To attain the output stabilization of a semiconductor laser and the deterioration of picture quality by keeping a laser beam oscillating section provided with the semiconductor laser and a collimation lens to a prescribed temperature so as to make the refractive index of a plastic lens constant. CONSTITUTION:The semiconductor laser 13 and the collimation lens 14 made of an acrylic resin are stored in the inside of a metallic cylider 16. A heat insulating agent 15 is provided at an outer wall of the metallic cylinder 16 and a temperature sensor 17 is positioned in its inside. A control circuit 18 is operated by a signal from the temperature sensor 17 and the temperature in the metallic cylinder 16 is made constant by controlling a temperature control element 19 adhered closely to the metallic cylinder 16.

Description

[Detailed description of the invention] 〔Technical field〕 The present invention relates to a semiconductor laser oscillator and plasti.

The present invention relates to an optical system control device for a laser beam printer that stabilizes the operation by controlling the temperature of a laser beam oscillation section having a collimation lens.

[Prior art]

As a conventional laser beam printer, there is one shown in FIG. 1, for example. This device includes a laser beam oscillation section (having a plastic collimation lens) 1, an image signal transmission section 2, a modulation section 3, a lens 4, a rotating polygon mirror 5, a recording drum 6, a charging corotron 7, a developing device 8, a transfer device 9, The fixing device 10, static eliminator 11, etc. are υ.

In the above configuration, the laser beam of the laser beam oscillation unit 1 is modulated by the modulation unit 3 according to the image signal 2, deflected by the rotating polygon mirror 5, focused by the lens 4, and scanned on the rotating recording drum 6, Form a latent image. This latent image is developed with a developer by a υ developing device 8 and transferred onto a recording paper 12 by a transfer device 9. The recording paper 12 is fixed by a fixing device 10,
After the transfer has been completed, the rotating recording dome 6 is neutralized by a static eliminator 11. Here, the laser beam oscillation section 1 is composed of a semiconductor laser and a plastic lens made of PMMA (acrylic resin) or the like, so that the structure can be simplified and costs can be reduced.

However, in the laser beam oscillator 1 of the conventional laser beam blink, the refractive index of the collimation lens and the optical output of the semiconductor laser change due to changes in the temperature of the atmosphere, resulting in a decrease in image quality. There is a fear.

[Object and structure of the invention]

The present invention was made in view of the above, and is intended to stabilize the refractive index of the plastic collimation lens, stabilize the optical output of the semiconductor laser, and completely prevent image quality deterioration. The present invention provides an optical system control device for a laser beam printer that maintains a laser beam oscillation section having a predetermined temperature at a predetermined temperature.

〔Example〕

The optical system control device for a laser beam printer according to the present invention will be explained in detail below.

FIGS. 2(A) and 2(B) show an embodiment of the present invention, in which a semiconductor laser 13 and, for example, acrylic resin and υ
A collimation lens 14 consisting of the following is housed inside a gold R cylinder 16. A VT heat agent 16 is provided on the outer wall of the metal cylinder 16, and a temperature sensor 17 is located inside the VT heat agent 16.

The temperature sensor 17 is connected to a control circuit 18 that inputs and processes signals, and the control circuit 18 controls a temperature control element 19 closely attached to the metal cylinder 16 via a drive circuit (not shown). There is. As the temperature control element 19, a Bertier element made of bonding different metals is preferable.
The temperature control means is not limited to the Vertier element, and other temperature control means may be used. metal tube 16
The shape is a rectangular parallelepiped with a square longitudinal section as shown in FIG. 2(b), but it may also be a rectangular parallelepiped with a rectangular cross section.

In the above configuration, the laser beam from the semiconductor laser 13 passes through the plastic collimation lens 14'ft,
At step 9, the laser beam exits through the other open end surface and scans the recording drum through the aforementioned modulation section, rotating polygon mirror, etc. When the ambient temperature inside the metal cylinder 16 of the laser beam oscillation unit 1 starts to rise, the control circuit 18 is activated by a signal from the temperature sensor 17, and when a DC current is passed through the Vertier element 19, which is made by joining dissimilar metals, the Peltier cord is activated. If the child 19 is in a heating mode when a positive current is passed through it, it is in a cooling mode when a negative direct current is passed therethrough, so that the P metal cylinder 16 is cooled by heat conduction. When the temperature inside the gold cylinder 16 is decreasing, if a positive current is passed through the Vertier element 19, the temperature will rise. Due to this temperature control and the fact that the outer wall is covered with the heat insulating material 15, the rising air inside the metal cylinder 16 can be kept constant regardless of the temperature of the outside air. Since it is desirable to keep the entire collimation lens 14 at the same temperature, the collimation lens 14 is
It is necessary to make the distance to the open part of the end face sufficiently long. Figure 3 (A), (→ shows a type in which the length of the metal tube 16 is sufficiently long and the front surface of the tube is covered with a glass plate 20. When sealed with the glass plate 20 in this way, the outside air is Since it does not penetrate into the metal tube 16, it is easy to maintain the atmosphere inside the metal tube 16 at a constant temperature.

Since the same numbers as in FIG. 2 are used in FIG. 3(a), ←), explanations of each part will be omitted. In addition, in order to uniformize the temperature inside the metal tube 16 as quickly as possible, a Bertier element 1 is used.
A plurality of fins 9 may be attached along the outer wall of the metal tube 16, or fins may be attached to the inner surface of the metal tube 16 to increase the heat transmission coefficient.

As mentioned above, if a plastic collimation lens, a semiconductor laser beam oscillator, and a temperature sensor are enclosed in a metal cylinder whose outer wall is covered with a heat insulating material, and a beam is generated by temperature-controlled means, the beam will not change because the temperature is constant. The shape and output are extremely stable. If the plastic collimation lens, semiconductor laser, and temperature sensor are not enclosed in a metal tube and are affected by the temperature of the outside air, for example, if the refractive index of PMMA resin is 1 at a temperature of 0°C, it will be 99. 76.99.6 at 50℃
0, the refractive index is less than the refractive index, and the influence of temperature is significant.

Further, the optical output characteristics of the semiconductor laser beam oscillator are shown in FIG. 4, and it is clear that even if the operating current is constant, the optical output changes significantly depending on the temperature. Therefore, if a plastic collimation lens or semiconductor laser is used in a place where it is affected by outside temperature, the shape and output of the laser beam will inevitably become unstable. The effect is great because the shape and output can be obtained in an extremely stable state.

〔Effect of the invention〕

As explained above, according to the optical system control device for a laser beam printer according to the present invention, the laser beam oscillation unit including the semiconductor laser and the collimation lens is maintained at a predetermined temperature, so that the refractive index of the plastic lens is kept constant. This makes it possible to stabilize the optical output of the semiconductor laser and prevent deterioration in image quality.

[Brief explanation of the drawing]

Fig. 1 shows a conventional laser beam printer cD ifQ 4 times, Fig. 2 (a) shows a vertical cross section of a laser beam oscillation section showing an embodiment of the present invention, and Fig. 2 (b) shows a cross section of a laser beam oscillation part showing an embodiment of the present invention. 3(a) is the M1 cross section of the modified laser beam oscillation part of the present invention, and FIG. 3(b) is the vertical cross section in the direction perpendicular to the axis of FIG.
FIG. 4 is a longitudinal section taken in a direction perpendicular to the axis of (b), and is an explanatory diagram of the optical output elongation of the semiconductor laser beam. Explanation of symbols 1... Laser beam oscillation unit, 2... Image signal transmission unit, 3... Modulation unit, 4... Lens, 5... Rotating polygon mirror, 6... Recording drum, 7 . . . Charged corotron, 8. Developing device, 9. Transfer device, 10. ...Fuser, 11...Static eliminator, 12...Paper, 13...
Semiconductor laser, 14... Glass collimation lens, 15... Heat insulating material, 16... Metal tube, 17
...Temperature sensor, 18...Control unit, 19...Temperature control element, 20...Glass. Patent applicant Fuji Xerox Co., Ltd. Agent Patent attorney Shin Matsubara 2 Patent attorney Seishunma Muraki Patent attorney Taira 1) Yudo Tadashi Patent attorney Atsushi Ueshima - Patent attorney Hitoshi Suzuki Figure 1, Figure 2, C-in (0) Figure 3) 7 (a) Continued from page 1 0 Author Hiroshi Osawa 2274 Hongo, Ebina City 0 Author Temple 1) Yuki 227 Hongo, Ebina City
Inventor Masuhisa Ogiwara 2274 Hongo, Ebina City
Fuji Xerox Co., Ltd. Ebinako Fuji Xerox Co., Ltd. Ebinako Fuji Xerox Co., Ltd. Ebinako

Claims (1)

[Claims] A laser beam printer that forms an electrostatic latent image on a photoreceptor with a laser beam modulated by an image signal, and performs development, transfer, and fixing based on the electrostatic latent image, comprising a semiconductor laser and plastic collimation. a laser beam oscillation section having a lens and whose temperature is controlled by a heating and cooling means; a temperature sensor that detects the temperature of the laser beam oscillation section; A control unit that controls the means, and +
Optical system control device for laser beam printer with 8 features.