JP2002131668A - Scanning optical device and image forming apparatus using the same - Google Patents

Abstract

(57) [Problem] To provide a scanning optical device capable of reducing the size of the entire device and an image forming apparatus using the same. SOLUTION: A light beam emitted from a light source means 6 is deflected by a deflecting means 2, an image of the light beam deflected by the deflecting means is formed on a surface 3 to be scanned by a scanning optical means 1, and the surface to be scanned is scanned. In a scanning optical device that performs optical scanning, the scanning optical unit has an internal reflection type optical element having a plurality of optical surfaces, the optical element being an incident surface on which a light beam deflected by the deflecting unit is incident, and the incident surface. A plurality of reflection surfaces for reflecting the light beam incident from the optical element a plurality of times inside the optical element, and an exit surface formed on the same side as the incident surface for emitting the light beam reflected by the reflection surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning optical apparatus and an image forming apparatus using the same, and more particularly, to an internal reflection type after a light beam modulated and emitted from a light source means is deflected by a rotary polygon mirror by an optical deflector. It is suitable for, for example, a laser beam printer or a digital copying machine having an electrophotographic process, in which image information is recorded by optically scanning the surface of a recording medium through a scanning optical unit having the above optical element.

Further, the present invention is suitable for, for example, a color laser beam printer, a color digital copying machine, and the like, which form a color image by using a plurality of the above-mentioned scanning optical devices.

[0003]

2. Description of the Related Art Conventionally, a laser beam printer (L)
In a scanning optical device used in a BP) or a digital copying machine, a light beam which is light-modulated and emitted from a light source means in accordance with an image signal is periodically deflected by, for example, a rotating polygon mirror by an optical deflector, and has an fθ characteristic. The light is focused into a spot on a photosensitive recording medium (photosensitive drum) surface by a scanning optical unit, and the surface is optically scanned to record an image.

FIG. 16 is a schematic view of a main part of a conventional scanning optical device of this kind.

In FIG. 1, a light beam emitted from a light source means 91 is converted into a substantially parallel light beam by a collimator lens 92.
A cylindrical lens 9 having a predetermined refractive power only in the sub-scanning direction after being shaped into an optimum beam shape by a stop 93.
4 is incident. Of the substantially parallel light beams incident on the cylindrical lens 94, they are emitted as they are in the state of substantially parallel light beams in the main scanning section. In the sub-scan section, the light is converged and formed as a substantially linear image on a deflection surface 95a of an optical deflector 95 formed of a rotating polygon mirror (polygon mirror).

The light beam deflected and reflected by the deflecting surface 95a of the optical deflector 95 is scanned by scanning optical means (fθ
The light is guided by a lens system 96 via a folding mirror 97 onto a photosensitive drum surface 98 as a surface to be scanned, and by rotating the optical deflector 95 in the direction of arrow A, the arrow B on the photosensitive drum surface 98 is moved. Optical scanning in the direction. Thus, an image is recorded on the photosensitive drum surface 98 as a recording medium.

Here, the main scanning direction is a direction parallel to the deflection scanning direction, and the sub-scanning direction is a direction perpendicular to the deflection scanning direction (main scanning direction).

[0008]

From the viewpoints of downsizing and cost reduction of a scanning optical device and an image forming apparatus using the same, a scanning optical device in a recent scanning optical device is covered by a polygon mirror as a deflecting device. The so-called short optical path length is realized by shortening the distance to the photosensitive drum surface that is the scanning surface.

Here, in order to achieve a short optical path length, a scanning optical means having a high angle of view must be used. As the angle of view increases, the degree of difficulty in designing the scanning optical means also increases. In recent years, from the traditional design of only a spherical surface, an aspherical surface is frequently used to satisfy optical performance and realize a short optical path length.

For example, in Japanese Patent Application Laid-Open No. 10-48552, a high angle of view and a short optical path length are obtained by making both surfaces of an optical element constituting a scanning optical unit aspherical. Here, if the optical element is formed of a glass material, the technical and cost disadvantages increase. Therefore, it is desirable that the optical element be formed by injection molding of a plastic material. As a result, the cost of a single lens can be reduced, and good optical performance can be obtained.

Another approach to miniaturization is to arrange a reflecting member (reflecting means) such as a return mirror in the optical path between the polygon mirror and the photosensitive drum surface, and to make the entire apparatus compact by folding the optical path. Method.

For example, in Japanese Patent Application Laid-Open No. Hei 10-39242, one folding mirror is arranged in the optical path, and the optical path of the light beam for scanning is folded downward in the apparatus to reduce the size of the entire apparatus.

However, in recent years, there has been an increasing demand for further miniaturization and cost reduction. However, it is very difficult in terms of design to further increase the angle of view and shorten the optical path length of the scanning optical means even if the aspherical surface is frequently used. Further, if it is attempted to reduce the spot diameter, the curvature of field needs to be corrected more strictly because the depth of focus becomes narrower, and it becomes difficult to obtain more excellent optical performance.

The arrangement of the reflecting member, which is another approach, tends to increase the cost due to an increase in the number of optical components. In addition, as the number of the reflecting members increases, the requirement for the positional accuracy of each reflecting member becomes stricter, which tends to further increase the cost.

Therefore, a scanning optical device in which at least one surface of the optical element constituting the scanning optical means is formed of a reflecting surface and the light beam is reflected by the reflecting surface to emit the light beam in a desired direction, For example, JP-A-9-686
Various proposals have been made in Japanese Patent Application Laid-Open No. 64, Japanese Patent Application Laid-Open No. H11-242178 and the like.

However, in these publications, the light beam is obliquely incident on the scanning surface including the optical axis of each surface on the incident surface and the exit surface of the optical element in the sub-scanning cross section. This causes the shape to be distorted due to the rotation of the scanning line, and the scanning line to be inevitably curved due to the design. If the shape of the spot is disturbed, a good image cannot be obtained due to a decrease in peak light amount, an increase in spot diameter, and the like.

In Japanese Patent Application Laid-Open No. H11-242178, the shape of the optical surface of the optical element constituting the scanning optical means is set so as to correct the curvature of the scanning line. However, such an optical element requires extremely high precision in production,
For example, the shape is not suitable for a large variation such as plastic injection molding, and it is difficult to evaluate a product.

On the other hand, in a color image forming apparatus for forming a color image by using a plurality of scanning optical devices, a registration shift (color shift) between the respective colors is required in order to form an image by overlapping a plurality of scanning lines. ) Is important. A color image forming apparatus having an adjustment mechanism for adjusting the registration deviation has been proposed in, for example, Japanese Patent Application Laid-Open No. 6-183056. In the publication, when performing registration adjustment using a plurality of reflection members,
By changing the position of the reflection member, color shift correction control is performed.

An object of the present invention is to provide a scanning optical device which can reduce the size of the entire device by forming the scanning optical means using an internal reflection type optical element having a plurality of optical surfaces.

Further, the present invention provides a scanning optical apparatus which can easily correct the inclination and / or the curvature of a scanning line on a surface to be scanned by decentering the internal reflection type optical element with respect to the scanning surface. The purpose is to provide.

A further object of the present invention is to provide an image forming apparatus capable of forming a good color image by forming an image forming apparatus using a plurality of the above-described scanning optical devices.

[0022]

According to a first aspect of the present invention, there is provided a scanning optical apparatus wherein a light beam emitted from a light source is deflected by a deflecting device, and the light beam deflected by the deflecting device is scanned by a scanning optical device. In forming an image on the surface and optically scanning the surface to be scanned, the scanning optical unit has an internal reflection type optical element having a plurality of optical surfaces, and the optical element is a light beam deflected by the deflection unit. Surface, a plurality of reflecting surfaces for reflecting the light beam incident from the incident surface a plurality of times inside the optical element, and formed on the same side as the incident surface for emitting the light beam reflected by the reflecting surface. It is characterized by having an emission surface.

According to a second aspect of the present invention, in the first aspect of the present invention, a light beam enters the incident surface of the optical element from a direction substantially parallel to a scanning surface formed by the light beam deflected by the deflecting means, and an exit surface. Are emitted from a direction substantially parallel to the scanning surface.

According to a third aspect of the present invention, in the first aspect, the entrance surface and the exit surface of the optical element have a refractive power,
The refractive power in the main scanning direction on those axes is sequentially represented by P
When 1, P2, the condition of P1 × P2 ≧ 0 is satisfied.

According to a fourth aspect of the present invention, in the first aspect of the present invention, each of the plurality of reflection surfaces of the optical element is reflected by total reflection.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the plurality of reflecting surfaces of the optical element are each coated.

According to a sixth aspect of the present invention, in the first aspect, the optical element is formed of a plastic material.

According to a seventh aspect of the present invention, in the first aspect of the present invention, the entrance surface and / or the exit surface of the optical element are formed of a refraction surface.

According to an eighth aspect of the present invention, in the first aspect, at least one of the entrance surface and the exit surface of the optical element is formed of a surface including a diffraction system.

A ninth aspect of the present invention is characterized in that, in the first aspect of the present invention, there is provided a detecting means for detecting an inclination and / or a curvature of a scanning line on the surface to be scanned.

According to a tenth aspect of the present invention, in the ninth aspect of the present invention, the optical element is decentered with respect to a scanning surface based on the detection information detected by the detecting means, so that the scanning on the scanning surface is performed. It is characterized in that the inclination or / and the curvature of the line are corrected.

An eleventh aspect of the present invention is characterized in that, in the tenth aspect of the present invention, the optical element is rotatable and eccentric about an axis parallel to the optical axis.

According to a twelfth aspect of the present invention, in the tenth aspect, the optical element is rotatable and eccentric about an axis parallel to the scanning surface and perpendicular to the optical axis.

According to a thirteenth aspect of the present invention, in the tenth aspect, the optical element is rotatable and eccentric about an axis parallel to the optical axis and / or an axis parallel to the scanning surface and perpendicular to the optical axis. It is characterized by having.

According to a fourteenth aspect of the present invention, in the first aspect of the present invention, the difference in shape between the entrance surface and the exit surface of the optical element in the main scanning section is reduced.

According to a fifteenth aspect of the present invention, there is provided an image forming apparatus according to any one of the first to fourteenth aspects, a photosensitive member disposed on the surface to be scanned, and scanning by the scanning optical device. A developing device for developing the electrostatic latent image formed on the photoreceptor as a toner image by the emitted light flux, a transfer device for transferring the developed toner image to a transfer material, and a transfer device for transferring the transferred toner image. A fixing device for fixing the material.

According to a sixteenth aspect of the present invention, there is provided an image forming apparatus according to any one of the first to fourteenth aspects, wherein the optical scanning device converts code data input from an external device into an image signal. And a printer controller that allows the user to input the data to the printer.

According to a seventeenth aspect of the present invention, there is provided an image forming apparatus comprising: a plurality of the scanning optical devices according to any one of the first to fourteenth aspects; A light image is guided on the surface of the image carrier, and the plurality of light beams scan each of the plurality of image carrier surfaces to form a color image.

In the scanning optical apparatus according to the present invention, the light beam emitted from the light source means is deflected by the deflecting means, and the light beam deflected by the deflecting means is imaged on the surface to be scanned by the scanning optical means. In a scanning optical device that optically scans the surface to be scanned, the scanning optical means has an internal reflection type optical element having a plurality of optical surfaces, and the optical element makes the light beam deflected by the deflection means incident thereon. An incident surface, a plurality of reflecting surfaces for reflecting a light beam incident from the incident surface a plurality of times inside the optical element, and an emitting surface formed on the same side as the incident surface for emitting the light beam reflected by the reflecting surface. Wherein the optical element is decentered with respect to the scanning surface formed by the light beam deflected by the deflecting means to correct the inclination or / and the curvature of the scanning line on the surface to be scanned. I have.

In a nineteenth aspect based on the eighteenth aspect, the light beam enters the entrance surface of the optical element in a direction substantially parallel to the scanning surface, and exits from the exit surface in a direction substantially parallel to the scanning surface. It is characterized by doing.

According to a twentieth aspect of the present invention, in accordance with the eighteenth aspect, there is provided detecting means for detecting the inclination or / and curvature of the scanning line on the surface to be scanned, and the optical element is detected by the detecting means. It is characterized in that it is decentered with respect to the scanning plane based on the detection information.

According to a twenty-first aspect of the present invention, in the eighteenth or twentieth aspect, the optical element is rotatable and eccentric about an axis parallel to the optical axis.

According to a twenty-second aspect, in the eighteenth aspect or the twentieth aspect, the optical element is rotatable and eccentric about an axis parallel to the scanning surface and perpendicular to the optical axis.

According to a twenty-third aspect, in the eighteenth or twentieth aspect, the optical element is rotationally eccentric about an axis parallel to the optical axis and / or an axis parallel to the scanning plane and perpendicular to the optical axis. It is characterized by being possible.

According to a twenty-fourth aspect, in the eighteenth aspect, the entrance surface and the exit surface of the optical element have a refractive power, and the refractive powers in the main scanning direction on their axes are respectively P1, P2. Then, a condition of P1 × P2 ≧ 0 is satisfied.

According to a twenty-fifth aspect of the present invention, in the eighteenth aspect, the reflection on the plurality of reflecting surfaces of the optical element is performed by total reflection.

According to a twenty-sixth aspect, in the eighteenth aspect, a coating process is applied to each of the plurality of reflection surfaces of the optical element.

According to a twenty-seventh aspect, in the eighteenth aspect, the optical element is formed of a plastic material.

According to a twenty-eighth aspect of the present invention, in the eighteenth aspect, the entrance surface and / or the exit surface of the optical element is formed of a refraction surface.

According to a twenty-ninth aspect, in the eighteenth aspect, at least one of the entrance surface and the exit surface of the optical element is formed of a surface including a diffraction system.

The invention of claim 30 is characterized in that, in the invention of claim 18, the difference in shape between the entrance surface and the exit surface of the optical element in the main scanning section is reduced.

According to a thirty-first aspect of the present invention, there is provided an image forming apparatus comprising: a scanning optical device according to any one of the eighteenth to thirteenth aspects;
A photoconductor arranged on the surface to be scanned, a developing device for developing an electrostatic latent image formed on the photoconductor by a light beam scanned by the scanning optical device as a toner image, and a developed toner image. The image forming apparatus is characterized in that it has a transfer device for transferring to a transfer material and a fixing device for fixing the transferred toner image to the transfer material.

According to a thirty-second aspect of the present invention, there is provided an image forming apparatus comprising: the optical scanning device according to any one of the eighteenth to thirtyth aspects;
A printer controller for converting code data input from an external device into an image signal and inputting the image signal to the optical scanning device.

According to a thirty-third aspect of the present invention, there is provided an image forming apparatus comprising a plurality of scanning optical devices according to any one of claims 18 to 30, wherein a plurality of light beams emitted from the respective scanning optical devices correspond to a plurality of light beams respectively. A light image is guided on the surface of the image carrier, and the plurality of light beams scan each of the plurality of image carrier surfaces to form a color image.

According to a thirty-fourth aspect of the present invention, the light beam emitted from the light source means is deflected by the deflecting means, and the light beam deflected by the deflecting means is imaged on the surface to be scanned by the scanning optical means. In a scanning optical device that optically scans the surface to be scanned, the scanning optical unit has a plurality of optical elements, and at least one of the optical elements is an internal reflection type optical element having a plurality of optical surfaces. An optical element having an incident surface on which the light beam deflected by the deflecting means is incident;
A plurality of reflecting surfaces for reflecting a light beam incident from the incident surface a plurality of times inside the optical element; and an emitting surface formed on the same side as the incident surface for emitting the light beam reflected by the reflecting surface. It is characterized by having.

According to a thirty-fifth aspect of the present invention, in the thirty-fourth aspect, a light beam enters the entrance surface of the optical element in a direction substantially parallel to a scanning surface formed by the light beam deflected by the deflecting means, and an exit surface. Are emitted from a direction substantially parallel to the scanning surface.

According to a thirty-sixth aspect, in the thirty-fourth aspect, the entrance surface and the exit surface of the optical element have a refracting power, and the powers in the main scanning direction on the axes thereof are P1 and P2, respectively. In this case, the condition that P1 × P2 ≧ 0 is satisfied.

In a thirty-seventh aspect based on the thirty-fourth aspect, reflection at the plurality of reflecting surfaces of the optical element is performed by total reflection.

According to a thirty-eighth aspect of the present invention, in the thirty-fourth aspect, each of the plurality of reflecting surfaces of the optical element is coated.

According to a thirty-ninth aspect, in the thirty-fourth aspect, the optical element is formed of a plastic material.

According to a fortieth aspect, in the thirty-fourth aspect, the entrance surface and / or the exit surface of the optical element are formed of a refraction surface.

According to a forty-first aspect, in the thirty-fourth aspect, at least one of the entrance surface and the exit surface of the internal reflection type optical element is formed of a surface including a diffraction system. .

The invention of claim 42 is characterized in that, in the invention of claim 34, there is provided a detecting means for detecting the inclination or / and the curvature of the scanning line on the surface to be scanned.

The invention of claim 43 is the invention of claim 42, based on the detection information detected by the detection means,
By decentering the optical element with respect to the scanning plane,
The tilt and / or the curvature of the scanning line on the surface to be scanned are corrected.

A forty-fourth aspect of the present invention is characterized in that, in the forty-third aspect, the optical element is rotatable and eccentric about an axis parallel to the optical axis.

A forty-fifth aspect of the present invention is based on the forty-third aspect, wherein the optical element is rotatable and eccentric about an axis parallel to the scanning surface and perpendicular to the optical axis.

According to a forty-sixth aspect, in the forty-third aspect, the optical element is rotatable and eccentric about an axis parallel to the optical axis and / or an axis parallel to the scanning plane and perpendicular to the optical axis. It is characterized by having.

According to a forty-seventh aspect, in the thirty-fourth aspect, a difference in shape between the entrance surface and the exit surface of the optical element in a main scanning section is suppressed to be small.

According to a forty-eighth aspect of the present invention, there is provided an image forming apparatus comprising: a scanning optical device according to any one of the thirty-fourth to forty-seventh aspects;
A photoconductor arranged on the surface to be scanned, a developing device for developing an electrostatic latent image formed on the photoconductor by a light beam scanned by the scanning optical device as a toner image, and a developed toner image. The image forming apparatus is characterized in that it has a transfer device for transferring to a transfer material and a fixing device for fixing the transferred toner image to the transfer material.

(49) The image forming apparatus according to (49), wherein the optical scanning device according to any one of (34) to (47) further comprises converting the code data input from an external device into an image signal to convert the code data into an image signal. And a printer controller that allows the user to input the data to the printer.

According to a fiftieth aspect of the present invention, there is provided an image forming apparatus comprising a plurality of scanning optical devices according to any one of the thirty-fourth to seventy-fourth aspects, wherein a plurality of light beams emitted from each of the scanning optical devices correspond to a plurality of light beams respectively. A light image is guided on the surface of the image carrier, and the plurality of light beams scan each of the plurality of image carrier surfaces to form a color image.

[0072]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment 1] FIG. 1 is a sectional view (main scanning sectional view) of a main scanning direction of a first embodiment of the present invention, and FIG. 2 is a sub scanning direction of the first embodiment of the present invention. 3 is a perspective view of a main part of the internal reflection type optical element 1 shown in FIGS. 1 and 2. FIG. In FIG. 2, the light source 6, the collimator lens 7, the aperture stop 8, the cylindrical lens 9 and the like are omitted.

In this specification, the surface formed by the light beam reflected and deflected by the deflecting means is defined as a scanning surface (main scanning section).

In the figure, reference numeral 6 denotes light source means, for example, a semiconductor laser. A collimator lens (condenser lens) 7 converts a light beam (light beam) emitted from the light source means 6 into a substantially parallel light beam. Reference numeral 8 denotes an aperture stop, which restricts a passing light beam (light amount). Numeral 9 denotes a cylindrical lens which has a predetermined power only in the sub-scanning direction, and applies a light beam passing through the aperture stop 8 to a deflecting surface (reflection surface) 2a of the optical deflector 2 described later in a sub-scanning section. The image is formed as a line image.

Reference numeral 2 denotes an optical deflector as a deflecting means, for example, a polygon mirror (rotating polygon mirror), which is rotated at a constant speed in the direction of arrow A in the figure by a driving means (not shown) such as a motor.

Reference numeral 1 denotes a scanning optical means, which is composed of a single internal reflection type optical element having fθ characteristics and formed of a plastic material. The internal reflection type optical element 1 has an incident surface (first surface) 1a on which a light beam deflected by the optical deflector 2 is incident, and a first light beam which reflects the light beam incident from the incident surface 1a a plurality of times inside the optical element 1. , The second two reflecting surfaces (second surface, third surface) 1c, 1d, and the incident surface 1a for emitting the light beams reflected by the first and second reflecting surfaces 1c, 1d to the surface to be scanned. The exit surface formed on the same side as
Surface) 1b. The light beam enters the entrance surface 1a of the internal reflection type optical element 1 from a direction substantially parallel to the scanning surface formed by the light beam deflected by the optical deflector 2, and from the exit surface 1b substantially coincides with the scanning surface. They are emitted from parallel directions.

Both the entrance surface 1a and the exit surface 1b of the internal reflection type optical element 1 in this embodiment are formed of refracting surfaces. In particular, the entrance surface 1a is an aspheric surface in the main scanning direction and a cylindrical surface in the sub scanning direction. The exit surface 1b is formed of a toric surface having different positive powers in the main scanning direction and the sub-scanning direction.

The surface shape of the internal reflection type optical element 1 in the main scanning direction is an aspherical surface, and the surface shape in the sub-scanning direction is a spherical surface whose radius of curvature continuously changes as the distance from the optical axis in the main scanning direction increases. ing. Optically, the entrance surface 1a and the exit surface 1
b, the first and second reflecting surfaces 1c, 1d are both formed as flat surfaces, and the first and second reflecting surfaces 1c, 1c,
1d is configured to form an angle of 90 degrees relatively.

Further, the internal reflection type optical element 1 in the present embodiment has the deflection surface 2a of the optical deflector 2 in the sub-scan section.
By providing a conjugate relationship between the scan target and the scanned surface 3, a tilt correction function is provided.

Reference numeral 3 denotes a photosensitive drum surface as a surface to be scanned.

In the present embodiment, the light beam emitted from the semiconductor laser 6 is converted into a substantially parallel light beam by the collimator lens 7, and the light beam (light amount) is restricted by the aperture stop 8 and is incident on the cylindrical lens 9. Of the substantially parallel light beam incident on the cylindrical lens 9, the light beam is emitted as it is in the main scanning section. In the sub-scanning section, the light converges and forms a substantially linear image (a linear image elongated in the main scanning direction) on the deflection surface 2a of the optical deflector 2.

The light beam deflected by the deflecting surface 2a of the optical deflector 2 is incident on the incident surface 1a of the internal reflection type optical element 1 from a direction parallel to the scanning plane including the optical axis. At the first and second reflecting surfaces 1c and 1d,
Light is emitted from the emission surface 1b in a direction parallel to the scanning surface including the optical axis. The emitted light beam is guided on the photosensitive drum surface 3 and the light deflector 2 is rotated in the direction of arrow A to optically scan the photosensitive drum surface 3 in the direction of arrow B at a constant speed. Thus, an image is recorded on the photosensitive drum surface 3 as a recording medium.

The surface shapes of the entrance surface 1a, the exit surface 1b and the first and second reflection surfaces 1c and 1d constituting the internal reflection type optical element 1 in this embodiment are based on the intersection of each surface with the optical axis. If the direction of the optical axis is the X axis, the direction perpendicular to the optical axis in the main scanning section is the Y axis, and the direction perpendicular to the optical axis in the sub-scanning section is the Z axis, the following expression can be obtained.

Main scanning direction: Aspherical shape expressed by the following function up to the 10th order

[0085]

(Equation 1)

Where R is the radius of curvature, K, B4, B6, B
8, B10 is an aspherical coefficient (when the coefficient has a suffix u, when the laser side is 1 from the optical axis, when it is on the anti-laser side than the optical axis) Sub-scanning direction: the radius of curvature continuously changes in the Y-axis direction R ′ = r (1 + D2Y ² + D4Y ⁴ + D6Y ⁶ + D8Y ⁸ +
D10Y ¹⁰ ) where r is the radius of curvature, and D2, D4, D6, D8, and D10 are aspherical coefficients (when the coefficient has a suffix u, when the laser side is 1 from the optical axis, and when the coefficient is the anti-laser side from the optical axis). 1 shows the optical arrangement in the present embodiment, and Table 2 shows the aspheric coefficient of each optical surface shape.

[0087]

[Table 1]

[0088]

[Table 2]

In this embodiment, of the four optical surfaces constituting the internal reflection type optical element 1, the entrance surface 1a and the exit surface 1a
The optical performances in the main scanning direction and the sub-scanning direction are satisfactorily corrected using the two surfaces b. Here, the entrance surface 1a and the exit surface 1
b has a refracting power (power), and assuming that the refracting power in the main scanning direction on those axes is P1 and P2, respectively, P1 × P2 ≧ 0 ‥‥‥ (1) You have set.

In this embodiment, P1 = 0.00171 P2 = 0.00404４０４P1 × P2 = 6.91 · 10 ⁻⁶ , which satisfies the conditional expression (1).

Conditional expression (1) is a condition for correcting the fθ characteristic and the field curvature. If the conditional expression (1) is not satisfied, the fθ characteristic and the field curvature in the main scanning direction are deteriorated, which is not good. In the present embodiment, by satisfying conditional expression (1), both the entrance surface 1a and the exit surface 1b have a convex shape on the optical deflector 2 side, which contributes to molding stability.

In the present embodiment, the light beam is reflected in a desired direction by using the first and second two reflecting surfaces 1c and 1d, and the scanning including the optical axis with respect to the entrance surface 1a and the exit surface 1b. A light beam is made to enter and exit from a direction parallel to the plane. Thereby, even if the light beam is three-dimensionally bent inside the optical element 1, good optical performance can be obtained without deterioration of optical performance such as spot rotation and scanning line curvature.

In this embodiment, the first and second reflecting surfaces 1 are used.
By setting the relative angle between c and 1d to 90 degrees, the light beams incident on the internal reflection type optical element 1 are emitted from different heights in the same direction. That is, by passing the light beam deflected by the light deflector 2 twice from the light deflector 2 to the internal reflection type optical element 1, the optical path length can be shortened by the distance. . At this time, the first and second reflection surfaces 1c and 1d are configured so that the light flux is totally reflected inside the internal reflection type optical element 1.

The refractive index n at the working wavelength of the internal reflection type optical element 1 in this embodiment is n as shown in Table 1.
= 1.5242, and assuming that the critical angle at which total reflection occurs is θ as shown in FIG. 4, sin θ = 1 / n ＝ θ = 41 (degrees). Therefore, the first with an incident angle of 41 degrees or more,
When a light beam is incident on the second reflecting surfaces 1c and 1d, the light beam is totally reflected by the first and second reflecting surfaces 1c and 1d.

In this embodiment, as shown in FIG. 5, since the incident angles of the light beams on the first and second reflecting surfaces 1c and 1d are both 45 degrees, the light beams are all internally reflected by the total reflection. The light is reflected and deflected in the element 1.

FIG. 6 is a diagram showing field curvature in the main scanning direction and the sub-scanning direction of the internal reflection type optical element 1, and FIG. 7 is a diagram showing distortion (fθ characteristic) and image height deviation. It can be seen that the optical performance is well corrected as shown in each figure.

Further, in this embodiment, a detecting means (not shown) for detecting the inclination of the scanning line on the surface to be scanned (photosensitive drum surface) 3 is provided. The inclination of the scanning line on the scanned surface 3 is corrected by decentering the internal reflection type optical element 1 based on the detection information.

That is, in this embodiment, there is provided feedback means for feeding back a signal from the detection means to the correction means (not shown), and performing scanning line correction based on the feedback.

FIG. 8 is an explanatory view showing the state of the inclination of the scanning line on the surface 3 to be scanned when the internal reflection type optical element 1 is rotated about the optical axis by, for example, 10 minutes.

As shown in the figure, an internal reflection type optical element 1
Is decentered about an axis parallel to the optical axis (X axis), whereby the scanning line can be tilted linearly.
In the present embodiment, the inclination of the scanning line is corrected by eccentrically rotating the internal reflection type optical element 1 about an axis parallel to the optical axis. That is, in the present embodiment, a stable and good image is always obtained by adopting a configuration in which the fluctuation of the scanning line is always detected by the detecting means and the scanning line is automatically corrected each time.

As described above, in this embodiment, the scanning optical means is constituted by a single internal reflection type optical element 1 as described above, so that the entire apparatus can be downsized. By rotating and decentering the optical element 1 about an axis parallel to the optical axis, the inclination of the scanning line on the surface 3 to be scanned can be favorably corrected.

[Second Embodiment] FIG. 9 is a cross-sectional view (main scanning cross-sectional view) of a main scanning direction according to a second embodiment of the present invention, and FIG. It is a figure (sub-scan sectional drawing). 9 and 10, the same elements as those shown in FIGS. 1 and 2 are denoted by the same reference numerals.

This embodiment is different from the above-described second embodiment in that the difference in shape between the entrance surface 5a and the exit surface 5b of the internal reflection type optical element 5 in the main scanning section is further reduced. Other configurations and optical functions are substantially the same as those of the first embodiment, and thus, similar effects are obtained.

That is, in the present embodiment, the curvature radius of the entrance surface 5a and the exit surface 5b of the internal reflection type optical element 5 and the aspheric coefficient K are made the same, so that both surfaces are formed close to each other. are doing. If the shape difference between the incident surface 5a and the emission surface 5b of the internal reflection type optical element 5 is large, the influence of shape errors and birefringence generated during molding increases, which is not good.

In this embodiment, as compared with the first embodiment, the shape of the exit surface 5b in the main scanning section is formed loosely, so that the edge of the lens can be taken with a sufficient margin. The reflective optical element 5 can be formed with a smaller lens thickness.

Table 3 shows the optical arrangement in the present embodiment, and Table 4 shows the aspheric coefficient of each optical surface shape.

[0107]

[Table 3]

[0108]

[Table 4]

The powers P1 and P2 in the main scanning direction on the axes of the entrance surface 5a and the exit surface 5b of the internal reflection type optical element 5 in this embodiment are as follows: P1 = 0.00287 P2 = 0.00287 ∴P1 × P2 = 1.16 · 10 ^-5 , which satisfies the conditional expression (1).

As shown in Table 3, the refractive index n of the internal reflection type optical element 5 in this embodiment at the operating wavelength is n.
= 1.5242, and when the light flux is incident on the first and second reflecting surfaces 5c and 5d at an incident angle of 41 degrees or more as in the first embodiment, the light flux is changed to the first and second reflection faces. Reflection surface 5c,
Total reflection occurs at 5d. In the present embodiment, since the incident angles of the light beams on the first and second reflecting surfaces 5c and 5d are both 45 degrees, all the light beams are reflected and deflected inside the internal reflection type optical element 5 by total reflection. become.

FIG. 11 is a diagram showing the field curvature of the internal reflection type optical element 5 in the main scanning direction and the sub-scanning direction, and FIG. 12 is a diagram showing distortion (fθ characteristic) and image height deviation. It can be seen that the optical performance is well corrected as shown in each figure.

FIG. 13 is an explanatory view showing the inclination of the scanning line on the surface 3 to be scanned when the internal reflection type optical element 5 is rotated about the optical axis by, for example, 10 minutes.

As shown in FIG.
Is decentered about an axis parallel to the optical axis, whereby the scanning line can be tilted linearly. In the present embodiment, the inclination of the scanning line is corrected by eccentrically rotating the internal reflection type optical element 5 about an axis parallel to the optical axis.

As described above, in this embodiment, the scanning optical means is constituted by a single internal reflection type optical element 5 as described above, so that the whole apparatus can be downsized. By suppressing the shape difference in the main scanning section between the entrance surface 5a and the exit surface 5b, the influence of shape errors and birefringence generated during molding can be reduced. By rotating and eccentric about an axis parallel to the optical axis, the inclination of the scanning line on the scanned surface 3 can be corrected.

In each of the first and second embodiments, the first and second reflection surfaces are formed as flat surfaces. However, if the total reflection is within a range, a curvature is provided and power is given. You may. In addition, both the entrance surface and the exit surface are formed of refracting surfaces, but either one of them may be used. In order to compensate for a focus shift or the like when a remarkable environmental change is caused by a plastic lens, at least one of the diffractive surfaces ( (Diffraction grating).

In each of the first and second embodiments, only the correction of the inclination of the scanning line is described. However, the present invention is not limited to this. For example, the detecting unit detects the bending (curvature) of the scanning line on the surface 3 to be scanned. By rotating and eccentrically rotating the internal reflection type optical element about an axis parallel to the scanning surface and perpendicular to the optical axis on the basis of the detected information, the bending of the scanning line on the surface to be scanned 3 can be reduced. Can be corrected.

Further, the optical element is rotated and decentered about an axis parallel to the optical axis of the internal reflection type optical element and an axis (Y axis) parallel to the scanning surface and perpendicular to the optical axis, thereby obtaining the optical element. Both the inclination of the scanning line and the bending of the scanning line on the surface to be scanned can be corrected simultaneously. It should be noted that the correction can also be made by rotating and eccentrically rotating the optical element about an axis perpendicular to the scanning plane.

In each of Embodiments 1 and 2 described above, the light beam is reflected using total reflection inside the optical element. However, the present invention is not limited to this. You may let it. The number of reflection surfaces of the optical element is not limited to two, but may be, for example, three or more, and the light beam may be deflected in a desired direction.

In each of the first and second embodiments, the scanning optical means is constituted only by a single internal reflection type optical element. However, the present invention is not limited to this. The same effects as those of the first and second embodiments can be obtained even if the optical element is formed of an internal reflection type optical element.

Further, a single internal reflection type optical element is composed of, for example, two optical elements (for example, the entrance surface 1a, the reflection surface 1c, and the new exit surface in the first embodiment) from the boundary between the entrance surface and the exit surface. A first optical element consisting of:
(A second optical element including a reflection surface 1d and an emission surface 1b).

[Image Forming Apparatus] FIG. 14 is a sectional view of a main portion in the sub-scanning direction showing an embodiment of an image forming apparatus (electrophotographic printer) using the scanning optical apparatus according to any one of the first and second embodiments. It is. In FIG. 14, reference numeral 104 denotes an image forming apparatus. Code data Dc is input to the image forming apparatus 104 from an external device 117 such as a personal computer. The code data Dc is converted into image data (dot data) Di by the printer controller 111 in the apparatus. This image data Di
Is input to the optical scanning unit 100. Then, from the optical scanning unit (scanning optical device) 100, a light beam (light flux) 103 modulated according to the image data Di is emitted.
One photosensitive surface is scanned in the main scanning direction.

The photosensitive drum 101 serving as an electrostatic latent image carrier (photoconductor) is rotated clockwise by a motor 115. Then, along with this rotation, the photosensitive surface of the photosensitive drum 101 moves in the sub-scanning direction orthogonal to the main scanning direction with respect to the light beam 103. Above the photosensitive drum 101, a charging roller 102 for uniformly charging the surface of the photosensitive drum 101 is provided so as to contact the surface.
The surface of the photosensitive drum 101 charged by the charging roller 102 is irradiated with a light beam 103 scanned by the optical scanning unit 100.

As described above, the light beam 103 is
The light is modulated based on the image data Di, and by irradiating the light beam 103, an electrostatic latent image is formed on the surface of the photosensitive drum 101. This electrostatic latent image is further moved from the irradiation position of the light beam 103 to the photosensitive drum 101.
Is developed as a toner image by a developing device 107 disposed so as to contact the photosensitive drum 101 on the downstream side in the rotation direction of the photosensitive drum 101. As the toner particles used here, for example, those having a sign opposite to the charge charged by the charging roller 102 are used. Then, a portion (image portion) where the toner adheres to the non-exposed portion of the photosensitive drum is formed. That is, in the present embodiment, so-called regular development is performed. In this embodiment, reversal development in which toner adheres to the exposed portion of the photosensitive drum may be performed.

The toner image developed by the developing device 107 is transferred below the photosensitive drum 101 onto a sheet 112 as a transfer material by a transfer roller 108 disposed so as to face the photosensitive drum 101. The paper 112 is stored in a paper cassette 109 in front of the photosensitive drum 101 (right side in FIG. 14), but can be fed manually. At the end of the paper cassette 109, the paper feed roller 1
10 are provided, and the paper 1 in the paper cassette 109 is provided.
12 to the transport path.

As described above, the sheet 112 on which the unfixed toner image has been transferred is further moved to the rear of the photosensitive drum 101 (FIG. 1).
3 is transported to the fixing device (left side). The fixing device has a fixing roller 113 having a fixing heater (not shown) therein.
And a pressure roller 114 disposed so as to be in pressure contact with the fixing roller 113. The paper 112 scattered from the transfer unit is transferred to the fixing roller 113 and the pressure roller 1.
The unfixed toner image on the paper 112 is fixed by heating while applying pressure at the pressure contact portion 14. Further, a paper discharge roller 116 is disposed behind the fixing roller 113, and discharges the fixed paper 112 to the outside of the image forming apparatus.

Although not shown in FIG. 14, the print controller 111 not only converts the explanation data, but also the motor 115 and other components in the image forming apparatus,
The control of the polygon motor and the like in the optical scanning unit 100 is performed.

[Color Image Forming Apparatus] FIG. 15 shows a case in which a plurality of the scanning optical apparatuses according to the first and second embodiments are simultaneously used, and image information for each color is recorded on different photosensitive drum surfaces. FIG. 2 is a schematic view of a main part of a color image forming apparatus on which an image is formed.

In the figure, reference numerals 11, 12, 13, and 14 denote scanning optical devices according to any of the first and second embodiments, respectively.
Reference numerals 21, 22, 23, and 24 denote photosensitive drums as image carriers, 31, 32, 33, and 34 denote developing units, respectively, and 41 denotes a conveyor belt.

In the color image forming apparatus shown in the figure, four scanning optical devices (11, 12, 13, 14) are arranged.
Each corresponds to each color of C (cyan), M (magenta), Y (yellow), and B (black), and image signals are recorded in parallel on the surfaces of the photosensitive drums (21, 22, 23, 24). , Which prints a color image at high speed.

In the figure, in particular, it is possible to eliminate a plurality of mirrors and to simplify the registration adjustment mechanism used for the registration adjustment mechanism for aligning four scanning lines in a conventional color image forming apparatus or the like, thereby enabling the entire apparatus to be manufactured. Simplification and cost reduction can be realized.

[0131]

According to the present invention, the scanning optical device is constituted by using the internal reflection type optical element having a plurality of optical surfaces as described above, so that the entire scanning device can be reduced in size. Can be achieved.

In addition, according to the present invention, the above-mentioned internal reflection type optical element is decentered with respect to the scanning surface, so that the inclination or / and the curvature of the scanning line on the surface to be scanned can be easily corrected. An optical device can be achieved.

Further, according to the present invention, by forming an image forming apparatus using a plurality of the above scanning optical devices, an image forming apparatus capable of forming a good color image can be achieved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part in a main scanning direction according to a first embodiment of the present invention (a main scanning sectional view);

FIG. 2 is a cross-sectional view of a main part in the sub-scanning direction according to the first embodiment of the present invention (sub-scanning cross-sectional view).

FIG. 3 is a perspective view of a main part of the internal reflection type optical element shown in FIGS. 1 and 2;

FIG. 4 is a diagram showing a critical angle of total reflection;

FIG. 5 is a diagram illustrating light flux reflection at a reflection angle according to the first embodiment of the present invention.

FIG. 6 is a diagram illustrating curvature of field in a main scanning direction and a sub scanning direction according to the first embodiment of the present invention.

FIG. 7 is a diagram illustrating distortion (fθ characteristic) and image height deviation according to the first embodiment of the present invention.

FIG. 8 is a diagram showing a scanning line inclination sensitivity according to the first embodiment of the present invention;

FIG. 9 is a cross-sectional view of main parts in the main scanning direction (main scanning cross-sectional view) according to the second embodiment of the present invention.

FIG. 10 is a sectional view of a main part in the sub-scanning direction according to the second embodiment of the present invention (sub-scanning sectional view);

FIG. 11 is a diagram illustrating curvature of field in a main scanning direction and a sub scanning direction according to the second embodiment of the present invention.

FIG. 12 is a diagram illustrating distortion (fθ characteristic) and image height deviation according to the second embodiment of the present invention.

FIG. 13 is a diagram showing a scanning line inclination sensitivity according to the second embodiment of the present invention;

FIG. 14 is a cross-sectional view of a main part in the sub-scanning direction showing a configuration example of an image forming apparatus (electrophotographic printer) using the scanning optical device of the present invention.

FIG. 15 is a configuration diagram of a main part of the color image forming apparatus of the present invention.

FIG. 16 is a schematic view of a main part of a conventional scanning optical device.

[Explanation of symbols]

 1,5 scanning optical means 2 deflecting means (optical deflector) 3 scanned surface (photosensitive drum surface) 6 light source means 7 collimator lens 8 aperture stop 9 cylindrical lens 11,12,13,14 scanning optical device 21,22 23, 24 Image carrier (photosensitive drum) 31, 32, 33, 34 Developing device 41 Conveying belt 100 Scanning optical device 101 Photosensitive drum 102 Charging roller 103 Light beam 104 Image forming device 107 Developing device 108 Transfer roller 109 Paper cassette 110 Feeding Paper roller 112 Transfer material (paper) 113 Fixing roller 114 Pressure roller 116 Discharge roller

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 1/113 H04N 1/04 104A F-term (Reference) 2C362 AA47 BA85 BA87 DA03 DA06 DA08 2H045 AA01 BA22 BA34 CA02 CA04 CA32 CA34 CA55 CA68 DA04 2H087 KA19 LA22 RA05 RA08 RA12 RA13 TA01 TA04 UA01 5C072 AA03 BA01 BA19 DA04 HA02 HA08 HA13 QA14 XA01 XA05

Claims (50)

[Claims] 1. A light beam emitted from a light source means is deflected by a deflecting means, an image of the light beam deflected by the deflecting means is formed on a surface to be scanned by a scanning optical means, and light scanning is performed on the surface to be scanned. In the scanning optical device, the scanning optical unit has an internal reflection type optical element having a plurality of optical surfaces, and the optical element is incident from the entrance surface, into which the light beam deflected by the deflecting unit is incident, from the entrance surface. It has a plurality of reflecting surfaces for reflecting a light beam a plurality of times inside the optical element, and an emitting surface formed on the same side as the incident surface for emitting the light beam reflected by the reflecting surface. Scanning optics. 2. A light beam enters the entrance surface of the optical element in a direction substantially parallel to a scanning surface formed by the light beam deflected by the deflecting means, and exits from an exit surface in a direction substantially parallel to the scanning surface. The scanning optical device according to claim 1, wherein 3. The incident surface and the exit surface of the optical element have a refractive power. When the refractive powers in the main scanning direction on the axes are P1 and P2, respectively, a condition of P1 × P2 ≧ 0 is satisfied. The scanning optical device according to claim 1, wherein the scanning optical device is satisfied. 4. The scanning optical apparatus according to claim 1, wherein the reflection on the plurality of reflection surfaces of the optical element is performed by total reflection. 5. The scanning optical device according to claim 1, wherein a coating process is applied to each of the plurality of reflection surfaces of the optical element. 6. The scanning optical device according to claim 1, wherein the optical element is formed of a plastic material. 7. The scanning optical device according to claim 1, wherein an entrance surface and / or an exit surface of said optical element is formed as a refraction surface. 8. The scanning optical device according to claim 1, wherein at least one of the entrance surface and the exit surface of the optical element is formed by a surface including a diffraction system. 9. The scanning optical apparatus according to claim 1, further comprising a detection unit configured to detect an inclination and / or a curvature of a scanning line on the surface to be scanned. 10. An inclination of a scanning line on the surface to be scanned or / and an eccentricity of the optical element with respect to a scanning surface based on the detection information detected by the detecting means.
10. The scanning optical device according to claim 9, wherein correction of curvature and curvature is performed. 11. The optical element according to claim 10, wherein the optical element is rotatable and eccentric about an axis parallel to the optical axis.
The scanning optical device according to claim 1. 12. The scanning optical apparatus according to claim 10, wherein said optical element is rotatable and eccentric about an axis parallel to a scanning surface and perpendicular to an optical axis. 13. The optical element according to claim 1, wherein the optical element is an axis parallel to an optical axis.
11. The scanning optical device according to claim 10, wherein the scanning optical device is capable of rotating and eccentric about an axis parallel to the scanning surface and perpendicular to the optical axis. 14. The scanning optical apparatus according to claim 1, wherein a shape difference in a main scanning section between the entrance surface and the exit surface of the optical element is suppressed to be small. 15. A scanning optical device according to claim 1, a photosensitive member disposed on the surface to be scanned, and a light beam scanned by the scanning optical device, the light beam being scanned on the photosensitive member. It has a developing device for developing the formed electrostatic latent image as a toner image, a transfer device for transferring the developed toner image to a transfer material, and a fixing device for fixing the transferred toner image to the transfer material. An image forming apparatus comprising: 16. An optical scanning device according to claim 1, further comprising: a printer controller that converts code data input from an external device into an image signal and inputs the image signal to the optical scanning device. An image forming apparatus comprising: 17. A plurality of scanning optical devices according to claim 1, wherein a plurality of light beams emitted from each of the scanning optical devices are guided on a corresponding one of a plurality of image carriers. An image forming apparatus for forming a color image by scanning each of the plurality of image carriers with the plurality of light beams. 18. A light beam emitted from a light source means is deflected by a deflecting means, an image of the light beam deflected by the deflecting means is formed on a surface to be scanned by a scanning optical means, and the surface to be scanned is optically scanned. In the scanning optical device, the scanning optical unit has an internal reflection type optical element having a plurality of optical surfaces, and the optical element is incident from the entrance surface, into which the light beam deflected by the deflecting unit is incident, from the entrance surface. A plurality of reflecting surfaces for reflecting the light beam a plurality of times inside the optical element, and an exit surface formed on the same side as the incident surface for emitting the light beam reflected by the reflecting surface; A scanning optical device for correcting the inclination or / and the curvature of a scanning line on the surface to be scanned by decentering the scanning surface formed by the light beam deflected by the means. 19. The optical device according to claim 1, wherein a light beam enters the entrance surface of the optical element in a direction substantially parallel to the scanning surface, and exits from the exit surface in a direction substantially parallel to the scanning surface.
9. The scanning optical device according to 8. 20. A detecting means for detecting a tilt or / and a curvature of a scanning line on the surface to be scanned, wherein the optical element is eccentric with respect to the scanning surface based on detection information detected by the detecting means. 19. The scanning optical device according to claim 18, wherein 21. The optical element according to claim 18, wherein the optical element is rotatable and eccentric about an axis parallel to the optical axis.
21. The scanning optical device according to 20. 22. The scanning optical device according to claim 18, wherein the optical element is rotatable and eccentric about an axis parallel to the scanning surface and perpendicular to the optical axis. 23. The optical element, wherein the optical element has an axis parallel to an optical axis and / or
And a rotation eccentricity about an axis parallel to the scanning surface and perpendicular to the optical axis.
The scanning optical device according to 0. 24. The incident surface and the exit surface of the optical element have a refractive power. When the refractive powers in the main scanning direction on their axes are P1 and P2, respectively, a condition of P1 × P2 ≧ 0 is satisfied. The scanning optical device according to claim 18, wherein the scanning optical device is satisfied. 25. The scanning optical device according to claim 18, wherein the reflection on the plurality of reflection surfaces of the optical element is performed by total reflection. 26. The scanning optical device according to claim 18, wherein a coating process is applied to each of the plurality of reflection surfaces of the optical element. 27. The scanning optical device according to claim 18, wherein said optical element is formed of a plastic material. 28. The optical device according to claim 1, wherein an entrance surface and / or an exit surface of the optical element is formed as a refraction surface.
9. The scanning optical device according to 8. 29. The scanning optical device according to claim 18, wherein at least one of the entrance surface and the exit surface of the optical element is formed by a surface including a diffraction system. 30. The scanning optical device according to claim 18, wherein a difference in shape between the entrance surface and the exit surface of the optical element in the main scanning section is suppressed to be small. 31. The scanning optical device according to claim 18, a photosensitive member disposed on the surface to be scanned, and a light beam scanned by the scanning optical device, on the photosensitive member. It has a developing device for developing the formed electrostatic latent image as a toner image, a transfer device for transferring the developed toner image to a transfer material, and a fixing device for fixing the transferred toner image to the transfer material. An image forming apparatus comprising: 32. An optical scanning device according to claim 18, further comprising: a printer controller that converts code data input from an external device into an image signal and inputs the image signal to the optical scanning device. An image forming apparatus comprising: 33. A plurality of scanning optical devices according to claim 18, wherein a plurality of light beams emitted from each scanning optical device are guided onto a corresponding plurality of image carrier surfaces. An image forming apparatus for forming a color image by scanning each of the plurality of image carriers with the plurality of light beams. 34. A light beam emitted from the light source means is deflected by a deflecting means, the light beam deflected by the deflecting means is imaged on a surface to be scanned by a scanning optical means, and the surface to be scanned is optically scanned. In the scanning optical device, the scanning optical means has a plurality of optical elements, at least one of which comprises an internal reflection type optical element having a plurality of optical surfaces, wherein the optical element is deflected by the deflecting means. An incident surface on which the reflected light beam is incident, a plurality of reflecting surfaces for reflecting the light beam incident from the incident surface a plurality of times inside the optical element, and formed on the same side as the incident surface for emitting the light beam reflected by the reflecting surface. A scanning optical device, comprising: a light exit surface. 35. A light beam enters the entrance surface of the optical element in a direction substantially parallel to a scanning surface formed by the light beam deflected by the deflecting means, and exits from an exit surface in a direction substantially parallel to the scanning surface. 35. The scanning optical device according to claim 34, wherein: 36. The incident surface and the exit surface of the optical element have a refractive power, and satisfying the following condition: P1 × P2 ≧ 0, where P1 and P2 are the powers in the main scanning direction on their axes, respectively. 35. The scanning optical device according to claim 34, wherein: 37. The scanning optical apparatus according to claim 34, wherein the reflection on the plurality of reflection surfaces of the optical element is performed by total reflection. 38. The scanning optical device according to claim 34, wherein a coating process is applied to each of the plurality of reflecting surfaces of the optical element. 39. The scanning optical device according to claim 34, wherein said optical element is formed of a plastic material. 40. The optical element according to claim 3, wherein an entrance surface and / or an exit surface of the optical element is formed as a refraction surface.
5. The scanning optical device according to 4. 41. The scanning optical device according to claim 34, wherein at least one of the entrance surface and the exit surface of the internal reflection type optical element is formed by a surface including a diffraction system. 42. The scanning optical apparatus according to claim 34, further comprising a detecting unit configured to detect an inclination and / or a curvature of a scanning line on the surface to be scanned. 43. Decentering the optical element with respect to a scanning surface based on the detection information detected by the detecting means, thereby tilting a scanning line on the surface to be scanned and / or
43. The scanning optical apparatus according to claim 42, wherein the correction of curvature and curvature is performed. 44. The optical element according to claim 43, wherein the optical element is rotatable and eccentric about an axis parallel to the optical axis.
The scanning optical device according to claim 1. 45. The scanning optical device according to claim 43, wherein the optical element is rotatable and eccentric about an axis parallel to the scanning surface and perpendicular to the optical axis. 46. The optical element has an axis parallel to an optical axis and / or
44. The scanning optical device according to claim 43, wherein the scanning optical device is rotatable and eccentric about an axis parallel to the scanning surface and perpendicular to the optical axis. 47. The scanning optical device according to claim 34, wherein a difference in shape between the entrance surface and the exit surface of the optical element in the main scanning section is suppressed to be small. 48. A scanning optical device according to claim 34, a photosensitive member disposed on the surface to be scanned, and a light beam scanned by the scanning optical device, on the photosensitive member. It has a developing device for developing the formed electrostatic latent image as a toner image, a transfer device for transferring the developed toner image to a transfer material, and a fixing device for fixing the transferred toner image to the transfer material. An image forming apparatus comprising: 49. An optical scanning device according to claim 34, further comprising: a printer controller that converts code data input from an external device into an image signal and inputs the image signal to the optical scanning device. An image forming apparatus comprising: 50. A plurality of scanning optical devices according to claim 34, wherein a plurality of light beams emitted from each scanning optical device are guided on a corresponding plurality of image carrier surfaces. An image forming apparatus for forming a color image by scanning each of the plurality of image carriers with the plurality of light beams.