JP7533288B2 - Optical device, optical writing device and image processing device - Google Patents

Description

The present invention relates to optical devices, optical writing devices, and image processing devices, and in particular to technology for suppressing vibration of optical elements such as mirrors in these devices.

An image processing device that forms an image by an electrophotographic method, such as a printer or an MFP (Multifunction Peripheral), is equipped with an optical writing device. The optical writing device is equipped with a light source, a deflector that deflects and scans the light emitted from the light source in the main scanning direction, and a scanning optical system that focuses the light deflected and scanned by the deflector on a predetermined image surface. For example, the deflector is composed of a polygon mirror or a galvanometer mirror. The scanning optical system is equipped with optical elements such as an fθ lens and a mirror, and is configured to focus the light guided from the deflector on the surface of an image carrier or the like. When an image is formed in the image processing device, a driving means such as a motor drives the deflector or the like at a specific frequency. Therefore, vibrations caused by driving the deflector or the like may be transmitted to the optical element. When the vibrations are transmitted to the optical element, the optical element vibrates, displacing the image position relative to the surface of the image carrier or the like, which causes deterioration of image quality.

In the past, various methods have been devised for holding optical elements in order to suppress the above-mentioned deterioration in image quality. For example, a method has been proposed for fixing a long, flat mirror to a housing by pressing and holding the mirror at multiple points in multiple directions that are perpendicular to each other, thereby suppressing vibration of the mirror (see, for example, Patent Document 1). In this conventional technology, the mirror is fixed by bonding to both the front and back sides of the long mirror in the thickness direction and pressing the mirror from one side to the other, and also by bonding to both sides of the mirror in the width direction and pressing the mirror from one side to the other.

However, if the input vibration frequency of an optical element (the frequency of vibration transmitted from the outside to the optical element) overlaps with the resonant frequency of the optical element, the amplitude of the optical element becomes extremely large, making it difficult to suppress the vibration of the optical element. For this reason, it is generally designed in advance so that the frequency used to drive a polarizer or the like does not overlap with the resonant frequency of the optical element.

However, in the case of the above-mentioned conventional technology in which a long optical element is pressed and held at multiple points in multiple directions perpendicular to each other, variations in the processing of the member that presses and holds the mirror, variations in the pressing force, assembly errors, changes in the input vibration strength, etc., occur in the transfer function of the vibration system including the optical element (the response amplitude of the optical element to external vibration) and the resonance frequency of the optical element. For example, in a configuration in which both ends of a long optical element are pressed and held in multiple directions, even if the resonance frequency of the optical element is set to a predetermined frequency during design and development, if the transfer function of the vibration system changes due to processing variations in the member that presses and holds the optical element, variations in the pressing force, assembly errors, changes in the input vibration strength, etc., the resonance frequency of the optical element will shift from the frequency set during design and development. If the input vibration frequency for the optical element overlaps with the shifted resonance frequency of the optical element, there is a problem that the vibration of the optical element will be greater than expected.

The above-mentioned variations are difficult to reproduce, so they are difficult to grasp in the early stages of development and are often only discovered in the later stages of development. This can lead to increased development man-hours and the need to add vibration control parts, which is an obstacle to efficient and inexpensive product development.

JP 2009-276395 A

The present invention has been made to solve the above-mentioned problems, and aims to provide an optical device, optical writing device, and image processing device that can suppress unexpected vibrations of optical elements by stabilizing the transfer function and resonance frequency, while reducing the increase in development labor and the need for additional vibration control equipment.

In order to achieve the above object, the present invention according to claim 1 is an optical device comprising an optical element having a predetermined length in a first direction, a predetermined thickness in a second direction perpendicular to the first direction, and a predetermined width in a third direction perpendicular to the first direction and the second direction, the predetermined length being longer than the predetermined thickness and the predetermined width, a first holding part that contacts both front and back surfaces of the optical element located in the second direction at both ends of the optical element in the first direction and holds the optical element in a state in which the front and back surfaces are pressed, and a first holding part that is arranged to face two side surfaces of the optical element located in the third direction at both ends of the optical element in the first direction with a gap wider than the predetermined width, and and a second holding portion that prevents the optical element from moving in the third direction, wherein the optical element is held by the first holding portion and the second holding portion in a state where no pressing force is applied in the third direction , the first holding portion comprising a first seating portion bonded to one of the front and back surfaces of the optical element, and a pressing portion that is positioned opposite the first seating portion and is bonded to the other of the front and back surfaces of the optical element to press the optical element toward the first seating portion, wherein the first seating portion is formed of a steel ball, and the pressing portion is formed of an elastic body and presses the optical element toward the first seating portion by the elastic force of the elastic body .

The invention of claim 2 is the optical device of claim 1 , characterized in that the first seating portion is in point contact with one of the front and back surfaces of the optical element, and the pressing portion is in point contact with the other of the front and back surfaces of the optical element.

The invention according to claim 3 is the optical device according to claim 1 or 2 , characterized in that the first seating portion is arranged at a plurality of positions in the third direction.
The invention of claim 4 is an optical device comprising: an optical element having a predetermined length in a first direction, a predetermined thickness in a second direction perpendicular to the first direction, and a predetermined width in a third direction perpendicular to the first direction and the second direction, the predetermined length being longer than the predetermined thickness and the predetermined width; a first holding portion that contacts both front and back surfaces of the optical element located in the second direction at both ends of the optical element in the first direction and holds the optical element in a state in which the front and back surfaces are pressed; and a second holding portion that is arranged at both ends of the optical element in the first direction to face two side surfaces of the optical element located in the third direction at a distance wider than the predetermined width, and prevents the optical element from moving in the third direction, wherein the optical element is held in a state in which no pressing force is applied in the third direction by the first holding portion and the second holding portion, and the second holding portion has a pair of protrusions facing each other and capable of making point contact with each of the two side surfaces of the optical element.
The invention according to claim 5 is the optical device according to claim 4, characterized in that the tip position of at least one of the pair of protrusions is adjustable in the third direction.
The invention according to claim 6 is an optical device comprising an optical element having a predetermined length in a first direction, a predetermined thickness in a second direction perpendicular to the first direction, and a predetermined width in a third direction perpendicular to the first direction and the second direction, the predetermined length being longer than the predetermined thickness and the predetermined width, a first holding part that contacts both front and back surfaces of the optical element located in the second direction at both ends of the optical element in the first direction and holds the optical element in a state in which the front and back surfaces are pressed, and a second holding part that is wider than the predetermined width at both ends of the optical element in the first direction. and a second holding portion arranged to face two side surfaces of the optical element positioned in the third direction at a predetermined distance therebetween and preventing the optical element from moving in the third direction, wherein the optical element is held in a state in which no pressing force is acting in the third direction by the first holding portion and the second holding portion, and the second holding portion comprises a second seating portion joined to one of the two side surfaces of the optical element and a falling-off prevention portion arranged at a position spaced a predetermined distance from the other of the two side surfaces of the optical element.
The invention according to claim 7 is the optical device according to claim 6, characterized in that the second seating portion has a higher rigidity than the anti-fall-off portion and is positioned at a lower position than the anti-fall-off portion.

The invention according to claim 8 is an optical device according to any one of claims 1 to 7 , characterized in that the second holding portions are arranged to face each other near the center of the side surfaces in the second direction.

The invention of claim 9 is an optical device of any of claims 1 to 8 , characterized in that the first holding portion and the second holding portion are provided at the same position in the first direction of the optical element.

The invention of claim 10 is an optical device of any of claims 1 to 9 , characterized in that the thickness dimension of the optical element in the second direction is smaller than the length in the first direction and the width in the third direction.

The invention of claim 11 is an optical device of any of claims 1 to 10 , further comprising a third holding portion arranged to face two end faces located in the first direction at a distance wider than the length of the optical element in the first direction, and preventing the optical element from moving in the first direction.

The invention according to claim 12 is an optical device according to any one of claims 1 to 11 , characterized in that the optical element has a rectangular parallelepiped shape.

The invention according to claim 13 is an optical device according to any one of claims 1 to 12 , characterized in that at least one of the front and back surfaces of the optical element is an optically functional surface.

The invention according to claim 14 is the optical device according to claim 13 , characterized in that the optical element has an optically functional surface which is a reflecting surface.

The invention of claim 15 is an optical writing device comprising a light source, a polarizer that deflects and scans light from the light source, and an optical device according to any one of claims 1 to 14 that is arranged in the direction of travel of the light that is deflected and scanned by the polarizer, and is characterized in that an image is written by light projected from the optical device.

The invention of claim 16 is an image processing device comprising an optical device according to any one of claims 1 to 14 , and characterized in that an image is read or written by light projected from the optical device.

According to the present invention, it is possible to minimize and stabilize the variation in the transfer function and resonance frequency of a vibration system including an optical element, and to suppress the phenomenon in which the optical element vibrates at an unexpected frequency. As a result, it is no longer necessary to take measures against vibration of the optical element in the later stages of development, which reduces the increase in development man-hours and the need to add vibration-proofing parts.

FIG. 1 is a diagram conceptually illustrating a basic configuration of an optical device. 11A to 11C are diagrams showing examples of holding modes for holding positions near both ends of an optical element. FIG. 1 is a conceptual diagram illustrating a comparative example of an optical device. FIG. 13 is a diagram illustrating an example of a change in a transfer function when a comparative example is adopted. 11A and 11B are diagrams illustrating an example of a change in a transfer function when the basic configuration of the optical device is adopted. FIG. 1 is a diagram illustrating an example of an internal structure of an image processing device. FIG. 1 illustrates an example of the configuration of an optical writing device. FIG. 2 is a perspective view showing a manner in which a mirror is held in an optical device. FIG. 2 is a front view of the optical device as seen from the polarizer side. FIG. 4 is an enlarged perspective view of a holding portion. FIG. 4 is a cross-sectional view showing one embodiment of a holding portion. FIG. 4 is an enlarged front view of the vicinity of an end of the mirror. FIG. 13 is a diagram showing a preferred installation position of the second seating portion. FIG. 11 is a cross-sectional view showing another embodiment of the holding portion. FIG. 13 is a cross-sectional view showing still another embodiment of the holding portion. FIG. 13 is a cross-sectional view showing still another embodiment of the holding portion. FIG.

Below, preferred embodiments of the present invention will be described in detail with reference to the drawings. Note that elements common to the embodiments described below are given the same reference numerals, and redundant descriptions of those elements will be omitted.

(Basic configuration of optical device)
First, the basic configuration of an optical device according to an embodiment of the present invention will be described. FIG. 1 is a conceptual diagram showing the basic configuration of the optical device. This optical device includes a holding portion 51 that holds both ends of an optical element 5 that is composed of a flat, elongated (rectangular parallelepiped) mirror or the like. The optical element 5 has a predetermined length in a first direction (X direction), a predetermined thickness in a second direction (Y direction) perpendicular to the first direction, and a predetermined width in a third direction (Z direction) perpendicular to each of the first and second directions. The length of the optical element 5 in the first direction is longer than the thickness in the second direction and the width in the third direction. The holding portion 51 is configured to hold both ends of the optical element 5 in the first direction (X direction), which is the longitudinal direction. The holding portion 51 includes a first holding portion 52 that is arranged along the second direction of the optical element 5, and a second holding portion 53 that is arranged along the third direction of the optical element 5.

The first holding portion 52 has two members 52a and 52b arranged to face each other across the optical element 5 in the second direction of the optical element 5. These two members 52a and 52b are in contact with each of the two surfaces (front and back) located in the second direction of the optical element 5. The front and back surfaces of the optical element 5 are perpendicular to the second direction. For example, the two members 52a and 52b are at the same position in the XZ plane, one member 52a is in point contact with the front surface of the optical element 5, and the other member 52b is in point contact with the back surface of the optical element 5. A pressing force F is applied to at least one member 52a of the two members 52a and 52b. This pressing force F acts in a direction from one member 52a toward the other member 52b. Therefore, the first holding portion 52 holds the optical element 5 in a state in which both the front and back sides are sandwiched between the two members 52a and 52b by the pressing force F.

The second holding portion 53 has two members 53a and 53b arranged to face each other with the optical element 5 in between in the third direction of the optical element 5. These two members 53a and 53b are arranged at a distance wider than the width dimension of the optical element 5 in the third direction. In addition, the two members 53a and 53b are arranged to face two side surfaces (both side surfaces) located in the third direction with respect to the third direction of the optical element 5. The two side surfaces of the optical element 5 are perpendicular to the third direction. For example, one member 53a of the two members 53a and 53b is in point contact with one side surface of the optical element 5. In contrast, the other member 53b is located at a position separated by a predetermined distance from the other side surface of the optical element 5. In addition, the two members 53a and 53b do not exert a pressing force like the first holding portion 52. Therefore, the second holding portion 53 does not hold the optical element 5 in a sandwiched state with respect to the third direction. In other words, the second holding portion 53 restricts the movement of the optical element 5 in the third direction. That is, the second holding portion 53 is provided as a fall prevention member to prevent the optical element 5 from moving in the third direction and coming off from the state where it is clamped by the first holding portion 52 when external vibration is transmitted to the optical element 5.

As described above, the optical device of this embodiment is basically configured to hold both ends of the optical element 5 that is long in the first direction, and the first holding portion 52 holds the optical element 5 in a sandwiched state with a pressing force F in the second direction (thickness direction) of the optical element 5, and the second holding portion 53 holds the optical element 5 in a state where no pressing force is applied to the optical element 5 in the third direction (width direction) of the optical element 5 so that the optical element 5 does not come off. With this holding mode, the optical device can stabilize the transfer function of the vibration system including the optical element 5 and the resonance frequency of the optical element 5.

Next, the transfer function of the vibration system including the optical element 5 and the stabilization of the resonance frequency of the optical element 5 will be described. FIG. 2 is a diagram showing an example of a holding mode for holding both ends of the optical element 5. FIG. 2(a) illustrates a case where both ends of the optical element 5 are simply supported. Here, simply supporting is, for example, a supporting mode in which support members 6, 6 are arranged on the back side of both ends of the optical element 5 and the optical element 5 is simply placed on the support members 6, 6. In this case, both ends of the optical element 5 are not fixed. In addition, since the thickness dimension of the optical element 5 in the second direction (Y direction) is smaller than the dimensions in other directions, when vibration is transmitted from the outside, vibration in the second direction appears prominently. Therefore, when vibration from the outside is transmitted to the optical element 5, the optical element 5 vibrates as shown in FIG. 2(b). In other words, the optical element 5 vibrates over the entire longitudinal direction (first direction). At this time, the optical element 5 does not displace in the second direction at the position supported by the support members 6, 6. However, the central portion of the optical element 5 is bent significantly, causing the optical element 5 to be displaced in the first direction at the position where it is supported by the support members 6, 6.

Figure 2(c) illustrates an example in which both ends of the optical element 5 are completely fixed. Here, completely fixed refers to a support mode in which both ends of the optical element 5 are fixed to a rigid body 7, so that both sides of the optical element 5 do not move at all. In this case, since both ends of the optical element 5 are completely fixed, when vibrations from the outside are transmitted to the optical element 5, the optical element 5 vibrates as shown in Figure 2(d). In other words, only the center part of the optical element 5, excluding both ends, vibrates. At this time, since both ends of the optical element 5 are completely fixed, they are not displaced in either the first direction or the second direction.

On the other hand, as shown in FIG. 1, in a case where the first holding portion 52 holds the optical element 5 in a sandwiched state with a pressing force F in the second direction (thickness direction) of the optical element 5, and the second holding portion 53 holds the optical element 5 in a state where no pressing force is applied to the optical element 5 in the third direction (width direction) of the optical element 5, the central portion of the optical element 5 vibrates in the second direction when an external vibration is applied to the optical element 5. When the vibration strength of the optical element 5 is relatively weak, the first holding portion 52 holds the optical element 5 near both ends so that it does not vibrate, resulting in a state close to the above-mentioned complete fixation. However, when the vibration strength of the optical element 5 is relatively strong, the optical element 5 tries to vibrate against the pressing force F of the first holding portion 52, resulting in a state close to the above-mentioned simple support.

Here, as a comparative example different from the basic configuration described above, an example will be described in which the second holding portion 53 applies a pressing force F to hold the optical element 5 in a sandwiched state in the third direction as well as in the second direction of the optical element 5. FIG. 3 is a conceptual diagram showing a comparative example of an optical device. Unlike the basic configuration described above, this optical device has two members 53a and 53b provided as the second holding portion 53 in contact with two surfaces (both side surfaces) perpendicular to the third direction of the optical element 5. A pressing force F is applied to at least one of the two members 53a and 53b. Therefore, the second holding portion 53 holds both side surfaces of the optical element 5 in a sandwiched state between the two members 53a and 53b by the pressing force F.

In the holding mode of the comparative example, when vibrations with a relatively weak input strength are applied from the outside to the optical element 5, the vicinity of both ends of the optical element 5 is in a state close to completely fixed, so the contact position between the second holding part 53 and the optical element 5 does not change, and static friction occurs between the second holding part 53 and the optical element 5. In contrast, when vibrations with a relatively strong input strength are applied from the outside to the optical element 5, the vicinity of both ends of the optical element 5 changes to a state close to simple support, so slippage occurs at the contact position between the second holding part 53 and the optical element 5, and kinetic friction occurs between the second holding part 53 and the optical element 5.

When dynamic friction occurs between the second holding portion 53 and the optical element 5, it affects the vibration of the optical element 5. In particular, in the case of a holding mode such as the comparative example, the frictional force acting between the second holding portion 53 and the optical element 5 increases in proportion to the pressing force F applied by the second holding portion 53, so the effect on the vibration of the optical element 5 is large. As a result, the transfer function of the vibration system including the optical element 5 and the resonant frequency of the optical element 5 change significantly depending on the strength of the vibration input to the optical element 5.

Figure 4 shows an example of the change in the transfer function when the input vibration strength is changed in a holding state such as the comparative example. As shown in Figure 4, in the comparative example, as the input vibration strength is increased in the order of I1, I2, I3, I4, and I5, the resonant frequency of the optical element 5 gradually changes to the low frequency range. In particular, if the optical element 5 is pressed and held not only in the second direction but also in the third direction as in the comparative example, the amount of change in the resonant frequency relative to the change in input vibration strength becomes large due to the effect of dynamic friction.

In contrast, in the basic configuration described above, when the first holding portion 52 holds the optical element 5 in a clamped state with a pressing force F in the second direction (thickness direction) of the optical element 5, and the second holding portion 53 holds the optical element 5 in a state where no pressing force is applied to the optical element 5 in the third direction (width direction) of the optical element 5, so that the optical element 5 does not come off, the amount of change in the transfer function and the resonant frequency can be kept small even if the vibration intensity input to the optical element 5 is changed.

Figure 5 shows an example of the change in the transfer function when the input vibration intensity is changed in the basic configuration of the optical device described above. As shown in Figure 5, in the basic configuration, as the input vibration intensity is increased in the order of I1, I2, I3, I4, and I5, the resonant frequency of the optical element 5 gradually shifts to a lower frequency range, but the amount of change is smaller compared to the comparative example. In other words, in the basic configuration, it is possible to limit the range in which the resonant frequency of the optical element 5 changes to a narrow range, and the transfer function and resonant frequency can be stabilized.

Therefore, by adopting the basic configuration described above, it is possible to set the frequency for driving the polarizer, etc., to a frequency band that does not overlap with the resonant frequency of the optical element 5 from the early stages of development, thereby reducing the increase in development man-hours and the need to add vibration control equipment. Below, we will explain specific embodiments that adopt the basic configuration described above.

First Embodiment
6 is a diagram showing the internal structure of an image processing device 1 according to an embodiment of the present invention. The image processing device 1 is a device that is configured with an MFP (Multifunction Peripheral) and is capable of forming images by an electrophotographic method. This image processing device 1 includes a printer unit 2 at the bottom of the device body and a scanner unit 3 at the top of the device body. The image processing device 1 also includes an operation panel 4 on the top front side of the device body that can be operated by the user.

The printer unit 2 includes a paper feed tray 10, a conveying path 11, a fixing unit 16, an image forming unit 20, and an optical writing device 30. The printer unit 2 picks up one sheet from a stack of sheets 9 stored in the paper feed tray 10 using a pickup roller 12 and a paper feed roller 13, and sends the sheet toward the conveying path 11. The sent-out sheet is conveyed along the conveying path 11 in the direction of the arrow F1. A timing roller 14, a secondary transfer roller 15, and a fixing unit 16 are arranged on the conveying path 11. When the leading edge of the sheet conveyed along the conveying path 11 reaches the timing roller 14, skew correction is performed. After that, the timing roller 14 is driven in accordance with the timing at which the toner image formed in the image forming unit 20 reaches the position of the secondary transfer roller 15, and the sheet is sent toward the secondary transfer roller 15. The toner image is transferred when the sheet passes the position of the secondary transfer roller 15. The sheet is then guided to the fixing unit 16, where it is heated and pressurized as it passes through the nip between the fixing roller 16a and the pressure roller 16b, fixing the toner image. The sheet with the fixed toner image is discharged from the paper discharge outlet 17 to a paper discharge tray 18 provided at the top of the printer unit 2.

The image forming unit 20 includes a pair of rollers 21, 22, an endless intermediate transfer belt 23 stretched over the rollers 21, 22, a number of developing units 24 provided below the intermediate transfer belt 23, and a number of primary transfer rollers 26 arranged to face each developing unit 24 across the intermediate transfer belt 23. Of the pair of rollers 21, 22, one roller 22 is a drive roller and contacts the secondary transfer roller 15 via the intermediate transfer belt 23. The other roller 21 is a driven roller. The intermediate transfer belt 23 stretched over the rollers 21, 22 circulates in the direction of the arrow F2 as the rollers 21, 22 are driven.

The multiple developing units 24 are units that form toner images corresponding to the colors Y (yellow), M (magenta), C (cyan), and K (black) and perform the primary transfer onto the intermediate transfer belt 23. For example, from the upstream side of the movement direction F2 of the intermediate transfer belt 23, developing unit 24Y that forms a Y toner image, developing unit 24M that forms an M toner image, developing unit 24C that forms a C toner image, and developing unit 24K that forms a K toner image are arranged. Toner bottles 28Y, 28M, 28C, and 28K are connected to these developing units 24Y, 24M, 24C, and 24K, and toner of each color is supplied from toner bottles 28Y, 28M, 28C, and 28K, respectively.

The developing unit 24 is provided with an image carrier 25 that is composed of a photosensitive drum or the like. The image carrier 25 is exposed to light by an optical writing device 30, and an electrostatic latent image is formed on the surface. The developing unit 24 visualizes the electrostatic latent image by attaching toner to it, and forms a toner image. The toner image formed on the image carrier 25 is primarily transferred to the surface of the intermediate transfer belt 23 as it passes a position facing the primary transfer roller 26. The toner image then moves toward the position of the secondary transfer roller 15 as the intermediate transfer belt 23 circulates, and is secondarily transferred to the surface of the sheet being transported along the transport path 11 as it passes the position of the secondary transfer roller 15.

The optical writing device 30 exposes the surface of the image carrier 25 by irradiating light 27 from a position below the developing unit 24 toward the surface of the image carrier 25 based on the image data to be printed, forming an image. As a result, an electrostatic latent image corresponding to the image data is formed on the surface of the image carrier 25. An example of the configuration of the optical writing device 30 will be described later.

The scanner unit 3 is equipped with an image reading device 40 that optically reads an image of a document placed on a platen glass 41 provided on the upper surface. The scanner unit 3 also has an opening and closing cover 42 located further above the platen glass 41.

The image reading device 40 includes two scanning members 43a and 43b, an optical system 48, and a light receiving element 49. The scanning member 43a is disposed on the lower surface side of the platen glass 41, and is driven by a driving means such as a motor (not shown) and can move back and forth in the direction of the arrow F3 (sub-scanning direction). The scanning member 43a includes a light source 44 that illuminates the surface (reading surface) of a document placed on the platen glass 41, and a mirror 45 that reflects the light reflected by the document surface, and can move in the sub-scanning direction while illuminating the document surface. The scanning member 43b, like the scanning member 43a, is driven by a driving means such as a motor (not shown) and can move back and forth in the direction of the arrow F3 (sub-scanning direction). The scanning member 43b includes two mirrors 46 and 47 that reflect the light reflected by the mirror 45 of the scanning member 43a toward the optical system 48 and the light receiving element 49. In addition, the scanning member 43b moves in the direction of the arrow F3 in conjunction with the movement of the scanning member 43a so that the optical path length from the light reflected by the surface of the document to the light receiving element 49 is always constant. The optical system 48 is an optical system that forms an image of the light reflected by the surface of the document on the light receiving element 49. The light receiving element 49 has a plurality of pixels arranged in the main scanning direction perpendicular to the sub-scanning direction, and generates an electrical signal according to the amount of light formed on each pixel by the optical system 48. The image reading device 40 generates image data corresponding to the image of the document by accumulating the electrical signals generated by the light receiving element 49 for each line in the main scanning direction in the sub-scanning direction while moving the two scanning members 43a and 43b in the sub-scanning direction.

In the image processing device 1 configured as above, the optical device having the above-mentioned basic configuration is implemented in, for example, the optical writing device 30. FIG. 7 is a diagram showing an example of the configuration of the optical writing device 30. The optical writing device 30 includes a light source 31, a polarizer 32, and an optical device 33. Note that the optical writing device 30 may be equipped with four units each including a light source 31, a polarizer 32, and an optical device 33 in order to write images corresponding to each of the colors Y, M, C, and K individually.

The light source 31 is a light source that emits light (e.g., laser light) for exposing the image carrier 25. The polarizer 32 is for deflecting and scanning the light from the light source 31, and includes a polygon mirror 36, a motor 37, and an optical system 35. The polygon mirror 36 is a rotating polyhedral mirror. The motor 37 is a driving means for rotating the polygon mirror 36 in a predetermined rotation direction (R direction). The optical system 35 is composed of, for example, an fθ lens.

Light L1 emitted from the light source 31 is irradiated at a predetermined position on the rotating polygon mirror 36 and is converted into light L2 that is deflected and scanned by the rotation of the polygon mirror 36. The light L2 is converted by the optical system 35 into light L3 that scans at a constant speed in the main scanning direction (X direction).

The optical device 33 is disposed in the traveling direction of the light L3 deflected and scanned by the polarizer 32, and converts the light L3 into light L4 directed toward the image carrier 25. The optical device 33 has a flat, elongated mirror 38 as an optical element 5 that converts the light L3 into light L4. That is, the optical element 5 in this embodiment has one of the front and back surfaces of the flat, elongated member (the front surface in this embodiment) as an optically functional surface, and is an element (mirror 38) formed with the optically functional surface as a reflective surface. The mirror 38 is inclined at a predetermined angle with respect to the traveling direction of the light L3, and can project the light L4 onto the surface of the image carrier 25 located above the optical writing device 30 to write an electrostatic latent image.

Figure 8 is a perspective view showing a manner in which the mirror 38 is held in the optical device 33. The mirror 38 is an elongated optical element 5 having a predetermined length in the first direction (X direction), and has, for example, a cubic shape. The mirror 38 also has a predetermined thickness in the second direction (Y direction) perpendicular to the first direction, and a predetermined width in the third direction (Z direction) perpendicular to each of the first and second directions. The mirror 38 has both surfaces located in the second direction (Y direction) formed as optically functional surfaces (reflecting surfaces). The optical device 33 has a housing 50 that holds the mirror 38 in a predetermined position. The housing 50 has a holding portion 51 that holds both ends 38a and 38b of the mirror 38 in the longitudinal direction (first direction). The holding portion 51 has a holding portion 51a provided on one end side of the mirror 38 and a holding portion 51b provided on the other end side.

9 is a front view of the optical device 33 seen from the polarizer 32 side. The holding portion 51 includes a first holding portion 52, a second holding portion 53, and a third holding portion 54. That is, the holding portion 51 includes the third holding portion 54 in addition to the first holding portion 52 and the second holding portion 53 described as the basic configuration. The first holding portion 52 holds both ends of the mirror 38 in the second direction of the mirror 38 by pinching and pressing both the front and back sides of the mirror 38. That is, the holding portion 51 fixes both ends of the mirror 38 to the housing 50 by the first holding portion 52. The second holding portion 53 is provided as a drop prevention member that prevents the mirror 38 from moving in the third direction and coming off the state held by the first holding portion 52. That is, the second holding portion 53 is for restricting the movement of the mirror 38 in the second direction. The third holding part 54 is provided as a fall prevention member that prevents the mirror 38 from moving in the first direction and coming off the state held by the first holding part 52. In other words, the third holding part 54 is intended to restrict the movement of the mirror 38 in the first direction.

Figure 10 is an enlarged perspective view of the holding portion 51 (51a). Figure 11 is a cross-sectional view of the holding portion 51 (51a), showing the A-A cross section in Figure 9. Note that Figures 10 and 11 show one holding portion 51a as an example, but the other holding portion 51b has a similar configuration.

As shown in FIG. 11, the housing 50 has inclined surfaces 61, 65 at both ends according to the arrangement angle of the mirror 38. The inclined surface 61 is parallel to the front surface 381 and the back surface 382 located in the second direction (Y direction) of the mirror 38, and the inclined surface 65 is parallel to the two side surfaces 383, 384 located in the third direction (Z direction) of the mirror 38. The inclined surface 61 is provided with a first seating portion 62 provided approximately in the center of the back surface 382 in the third direction of the mirror 38. The inclined surface 65 is provided with a second seating portion 66 provided approximately in the center of one side surface 383 in the second direction of the mirror 38.

The first seating portion 62 supports the mirror 38 in contact with the back surface 382 of the mirror 38. For example, the first seating portion 62 is formed by providing a recess 63 in the inclined surface 61 and fitting a highly rigid stainless steel ball 64 into the recess 63. Since the depth of the recess 63 is smaller than the diameter of the steel ball 64, when the steel ball 64 is fitted into the recess 63, a part of the steel ball 64 forms a protrusion that protrudes from the surface of the inclined surface 61. The back surface 382 of the mirror 38 is supported in a state of contact at one point with the protrusion of the steel ball 64. Such a first seating portion 62 forms a part of the first holding portion 52 (member 52b shown in FIG. 1).

The second seat 66 supports the mirror 38 in contact with one side 383 of the mirror 38. For example, the second seat 66 is formed by providing a recess 67 in the inclined surface 65 and fitting a highly rigid steel ball 68 into the recess 67, similar to the first seat 62. Since the depth of the recess 67 is smaller than the diameter of the steel ball 68, when the steel ball 68 is fitted into the recess 67, a part of the steel ball 68 forms a protrusion protruding from the surface of the inclined surface 65. One side 383 of the mirror 38 is supported in a state of contact at one point with the protrusion of the steel ball 68. Such a second seat 66 forms part of the second holding part 53 (member 53a shown in FIG. 1).

In addition, a holding member 70 is attached to the housing 50 in correspondence with both ends of the mirror 38. The holding member 70 is a leaf spring-like member formed of, for example, resin. The holding member 70 includes a flat mounting portion 71 attached to the housing 50, a pressing portion 73 extending from the mounting portion 71 and contacting the surface 381 of the mirror 38 to press the mirror 38 toward the inclined surface 61, a first fall prevention portion 75 extending from the mounting portion 71 and arranged parallel to the other side surface 384 at a position spaced apart from the other side surface 384 of the mirror 38 by a predetermined distance, and a second fall prevention portion 81 extending from the side of the first fall prevention portion 75 so as to wrap around the end surface 385 of the mirror 38 in the longitudinal direction (X direction) and arranged parallel to the end surface 385 at a position spaced apart from the end surface 385 of the mirror 38 by a predetermined distance.

For example, the mounting portion 71 of the holding member 70 is positioned at a predetermined position on the housing 50 by pins 58 and 59 provided on the housing 50, and is fixed at the positioned position by a screw 57.

The pressing portion 73 is formed of an elastic body having a roughly L-shaped leaf spring structure, one end of which is connected to the mounting portion 71, and the other end of which has a flat plate portion parallel to the surface 381 of the mirror 38. The pressing portion 73 has a protrusion 74 that protrudes in a semi-spherical shape toward the surface 381 of the mirror 38 at a predetermined position of the flat plate portion parallel to the surface 381 of the mirror 38. The protrusion 74 is in the same position in the XZ plane as the first seating portion 62 provided on the inclined surface 61 of the housing 50. The pressing portion 73 is attached in a state in which the tip of the protrusion 74 is in contact with the surface 381 of the mirror 38 at one point, and the mirror 38 is pressed toward the first seating portion 62 by the elastic force (biasing force) of the elastic body of the leaf spring structure. In other words, the first holding portion 52 that holds the mirror 38 in a pressed state in the second direction (Y direction) of the mirror 38 is formed by two members: the pressing portion 73 of the holding member 70 and the first seating portion 62 provided on the housing 50.

The first anti-fall-off portion 75 may be formed so as to extend from the mounting portion 71 integrally with the pressing portion 73 as described above, or may be formed so as to extend from the mounting portion 71 in an independent form separate from the pressing portion 73.

The first anti-falling part 75 has a flat plate part parallel to one side 384 of the mirror 38, and further has a protrusion part 76 that protrudes in a hemispherical shape toward the side 384 of the mirror 38 at a predetermined position of the flat plate part. As shown in FIG. 11, the protrusion part 76 is arranged so that its tip does not abut the side 384 of the mirror 38, and a certain gap is maintained between the side 384 of the mirror 38 and the side 384 of the mirror 38. This protrusion part 76 is located in the same position as the second seat part 66 provided on the inclined surface 65 of the housing 50 in the XY plane. Such a first anti-falling part 75 is intended to prevent the mirror 38 from moving in the third direction (Z direction) and falling off when vibration from the outside is transmitted. In other words, the first anti-fall-out portion 75 and the second seat portion 66 provided on the housing 50 form the second holding portion 53, which prevents the mirror 38 from moving in the third direction (Z direction) and coming loose from the state held by the first holding portion 52.

The second fall-off prevention part 81 is connected to the flat part of the first fall-off prevention part 75 as described above, and has a flat part parallel to the end face 385 of the mirror 38. FIG. 12 is an enlarged view of the vicinity of the end of the mirror 38 seen from the front side. The flat part of the second fall-off prevention part 81 is located at a predetermined distance from the end face 385 of the mirror 38. The second fall-off prevention part 81 also has a protrusion 82 that protrudes in a hemispherical shape toward the end face 385 of the mirror 38 at a predetermined position of the flat part. The tip of this protrusion 82 is not abutted against the end face 385 of the mirror 38, and is arranged in a state where there is a certain gap between the end face 385 of the mirror 38 and the mirror 38. Such a second fall-off prevention part 81 is intended to prevent the mirror 38 from moving in the first direction (X direction) and falling off when vibration from the outside is transmitted. The third retaining portion 54 is formed by arranging such second fall prevention portions 81 close to both longitudinal end faces of the mirror 38.

As described above, the holding portion 51 of the optical device 33 holds both sides of the mirror 38 in a sandwiched state by applying a pressing force only in the second direction (Y direction) which is the thickness direction of the mirror 38 with the first holding portion 52, and fixes it to the housing 50. In other words, the second holding portion 53 and the third holding portion 54 of the holding portion 51 hold the mirror 38 so that it does not fall off the holding portion 51 without applying a pressing force to the mirror 38 in the first direction (X direction) which is the longitudinal direction of the mirror 38 and in the third direction (Z direction) which is the width direction of the mirror 38. Therefore, the position where the mirror 38 contacts the first holding portion 52 becomes a fixed point, and if external vibration is transmitted to the mirror 38, the mirror 38 vibrates with the fixed point as a fulcrum.

In this embodiment, the second holding portion 53 supports the mirror 38 in an inclined state, so that the second seating portion 66 is disposed lower in the direction of gravity than the first fall prevention portion 75, and the second seating portion 66 is in a state of being joined to one side surface 383 of the mirror 38. Therefore, when external vibration is transmitted to the mirror 38 and the mirror 38 vibrates, slippage occurs between the second seating portion 66 and the side surface 383 of the mirror 38, and friction between the second seating portion 66 and the side surface 383 of the mirror 38 may change from static friction to kinetic friction. To prevent this, it is preferable that the second seating portion 66 is disposed so as to contact the center of the side surface 383 of the mirror 38 in the thickness direction (second direction) of the mirror 38.

13 is a diagram showing a preferred installation position of the second seating portion 66. FIG. 13(a) shows a state in which the mirror 38 is vibrated so as to be convex upward, with the position clamped by the first holding portion 52 as a fixed point. In the state shown in FIG. 13(a), tensile deformation occurs on the upper side of the mirror 38 (the side closer to the protrusion 74 in the second direction (Y direction)), and compressive deformation occurs on the lower side of the mirror 38 (the side closer to the first seating portion 62 in the second direction (Y direction)). Next, FIG. 13(b) shows a state in which the mirror 38 is vibrated so as to be convex downward, with the position clamped by the first holding portion 52 as a fixed point. In the state shown in FIG. 13(b), compressive deformation occurs on the upper side of the mirror 38, and tensile deformation occurs on the lower side of the mirror 38. In this way, when the mirror 38 is vibrated with the position clamped by the first holding portion 52 as a fulcrum, the displacement amount due to tensile or compressive deformation is small at the point on the center line 387 of the mirror 38. In particular, the central position P1, which is the intersection point of the line connecting the two points held by the first holding portion 52 and the central line 387, is least deformed by tensile deformation and compressive deformation, and the amount of displacement is negligibly small. Therefore, by bringing the second seating portion 66 into contact with the central position P1 of the mirror 38, the second seating portion 66 can support a position that does not displace even when the mirror 38 vibrates, and it is possible to prevent the friction with the mirror 38 from changing from static friction to kinetic friction. Therefore, even if the vibration input strength to the mirror 38 changes, it is possible to stabilize the transfer function of the vibration system including the mirror 38 and the resonance frequency of the mirror 38.

It is also preferable that the protrusion 76 of the first fall-off prevention part 75 facing the second seating part 66 is configured to come into contact with the center position P1 of the mirror 38 when the mirror 38 moves in the third direction (Z direction) and comes into contact with the side surface 384 of the mirror 38. Therefore, like the second seating part 66, the protrusion 76 of the first fall-off prevention part 75 is also preferably positioned at the center position P1 of the mirror 38 in the second direction (Y direction).

Figure 14 is an assembly diagram of the optical device 33. The first seat 62 and the second seat 66 are installed in advance on the inclined surfaces 61, 65 provided at both ends of the housing 50. That is, the first seat 62 and the second seat 66 are installed by fitting the steel balls 64, 68 into the recesses 63, 67 provided in the inclined surfaces 61, 65. The mirror 38 is placed on the first seat 62 and the second seat 66. At this time, the mirror 38 is supported at a point near the center of one side surface 383 by the steel ball 68, and is supported at a point near the center of the back surface 382 by the steel ball 64. The steel balls 64, 68 are highly rigid members, so that the holding position of the mirror 38 can be stabilized. Once the mirror 38 is placed on the first seat 62 and the second seat 66, the holding members 70 are then attached to both ends of the housing 50.

The housing 50 has two pins 58, 59 and a screw hole 57a in the portion where the holding member 70 is attached. On the other hand, the mounting portion 71 of the holding member 70 has holes 71a, 71b into which the two pins 58, 59 are fitted, and a hole 71c into which the screw 57 is inserted. Of the two holes 71a, 71b, one hole 71a is formed as an elongated hole having a predetermined length in the X direction. By fitting the pins 58, 59 into each of the two holes 71a, 71b, the holding member 70 is positioned at a predetermined position at the end of the housing 50. In this state, the position of the mirror 38 in the first direction (X direction) can be adjusted to adjust the positions of both end faces 385, 386 of the mirror 38 in the longitudinal direction relative to the second fall-off prevention portion 81. Then, the retaining member 70 is fixed at a predetermined position in the housing 50 by inserting the screw 57 into the hole 71c of the mounting portion 71 and screwing it into the screw hole 57a. As a result, the pressing portion 73 of the retaining member 70 abuts the protrusion 74 against the surface 381 of the mirror 38 and presses the mirror 38 toward the first seating portion 62. The first fall prevention portion 75 of the retaining member 70 holds the protrusion 76 at a position spaced a predetermined distance from the side surface 384 of the mirror 38, and does not apply a pressing force in the third direction (Z direction) to the mirror 38.

The pressing force of the pressing portion 73 can be adjusted by the degree of tightening of the screw 57 into the screw hole 57a. However, even if the pressing force of the pressing portion 73 becomes relatively strong, the mirror 38 can be held in a predetermined position without distorting the mirror 38 because the back surface 382 of the mirror 38 is supported by the highly rigid steel ball 64. Therefore, by attaching the holding member 70 to the housing 50 as described above, it is possible to easily and highly accurately adjust the positions of the first anti-falling portion 75 and the second anti-falling portion 81 relative to the mirror 38. Therefore, the assembly work of the mirror 38 to the housing 50 can be performed efficiently.

Therefore, the optical device 33 of this embodiment has the advantage of being able to stabilize the transfer function of the vibration system including the mirror 38 and the resonant frequency of the mirror 38, as well as improving the work efficiency when assembling the mirror 38 to the housing 50.

Second Embodiment
Next, Fig. 15 is a cross-sectional view showing another embodiment of the holding part 51. In the holding part 51 shown in Fig. 15, a first seating part 62 is formed by a protrusion 83 formed on the inclined surface 61 of the housing 50, and a second seating part 66 is formed by a protrusion 84 formed on the inclined surface 65 of the housing 50. For example, the protrusions 83, 84 are formed in a cone or pyramid shape, and support the mirror 38 with their tips in contact with the back surface 382 or side surface 383 of the mirror 38. These protrusions 83, 84 are integrally formed with the inclined surfaces 61, 65 when the housing 50 is formed, so there is no need to fit the steel balls 64, 68 as in the first embodiment. This has the advantage that the assembly work of the optical device 33 can be performed more efficiently.

In FIG. 15, an example is shown in which the protrusion 74 provided on the pressing portion 73 protrudes in a semispherical shape, as in the first embodiment, but this is not limited to this. That is, the protrusion 74 may be in a conical or pyramidal shape. The same is true for the protrusion 76 provided on the first fall-off prevention portion 75, and the protrusion 76 may be in a conical or pyramidal shape.

All other aspects of this embodiment are the same as those described in the first embodiment.

Third Embodiment
Next, Fig. 16 is a cross-sectional view showing yet another embodiment of the holding portion 51. As shown in Fig. 16(a), in this holding portion 51, the recesses 63, 67 formed in the inclined surfaces 61, 65 of the housing 50 are formed as circular screw holes 63a, 67a. The screw holes 63a, 67a are fitted with protruding members 85, 86. The protruding members 85, 86 are formed with a hemispherical tip end and a male screw 87 that screws into the screw hole 63a, 67a is formed on the base end. The protruding members 85, 86 are attached in a state in which the hemispherical tip end protrudes from the surface of the inclined surface 61, 65 by screwing the male screw 87 into the screw hole 63a, 67a.

Figure 16 (b) shows the state in which the protruding members 85, 86 are attached to the inclined surfaces 61, 65 of the housing 50. In this embodiment, the first seating portion 62 is configured by mounting the protruding member 85 to the screw hole 63a provided in the inclined surface 61. Similarly, the second seating portion 66 is configured by mounting the protruding member 86 to the screw hole 67a provided in the inclined surface 65. The first seating portion 62 and the second seating portion 66 having such a configuration can adjust the height position of the hemispherical tip protruding from the inclined surfaces 61, 65 by adjusting the embedding amount of the male screw 87 into the screw hole 63a, 57a. That is, the protruding member 85 constituting the first seating portion 62 can adjust its tip position in the second direction (Y direction), and the protruding member 86 constituting the second seating portion 66 can adjust its tip position in the third direction (Z direction).

By making the tip position of the protrusion member 85 adjustable in the second direction, it is possible to adjust the pressure with which the first holding part 52 presses the mirror 38. In other words, by adjusting the tip position of the protrusion member 85, the pressure by the first holding part 52 can be adjusted so that it is always constant. As a result, the transfer function of the vibration system including the mirror 38 and the resonance frequency of the mirror 38 can be further stabilized.

In addition, by adjusting the tip position of the protrusion member 86 in the third direction, it is possible to adjust the distance between the protrusion 76 facing the protrusion member 86 and the side surface 384 of the mirror 38. Therefore, there is an advantage that the distance between the side surface 384 of the mirror 38 and the protrusion 76 can be adjusted to a constant state. In addition, if the protrusion 76 hits the side surface 384 of the mirror 38 when the holding member 70 is attached to the housing 50, the protrusion 76 can be adjusted so that it does not hit the side surface 384 of the mirror 38 by increasing the embedment amount of the protrusion member 86 in the screw hole 67a, so there is also the advantage that the effects of processing variations in the holding member 70 can be eliminated.

In FIG. 16, screw holes 63a, 67a are provided on the inclined surfaces 61, 65, and the protruding members 85, 86 are attached to the screw holes 63a, 67a, but this is not limited to the above. For example, screw holes may be provided in the flat plate portion constituting the pressing portion 73 or the first fall-off prevention portion 75, and the above-mentioned protruding members may be attached to the screw holes.

All other aspects of this embodiment are the same as those described in the first embodiment.

Fourth Embodiment
Next, FIG. 17 is a cross-sectional view showing yet another embodiment of the holding portion 51. In this holding portion 51, the first holding portion 52 contacts multiple points on both the front and back surfaces 381, 382 of the mirror 38 to hold the mirror 38 in a pressed state. For example, the inclined surface 61 of the housing 50 is provided with the first seating portions 62 at two positions similar to those in the first embodiment. The first seating portions 62 provided at the two positions contact the back surface 382 of the mirror 38, respectively. In addition, the pressing portion 73 is formed with protrusions 74, 74 at two positions facing the first seating portion 62. The pressing portion 73 brings the two protrusions 74, 74 into contact with the surface 381 of the mirror 38 to press the mirror 38 toward the first seating portion 62. In this way, the first holding portion 52 clamps the mirror 38 in a pressed state on both the front and back surfaces. In this manner, the first holding portion 52 holds the mirror 38 by contacting multiple points on both the front and rear surfaces 381, 382 of the mirror 38, thereby making it possible to stably hold the mirror 38.

As described above, the first holding portion 52 may be provided at both ends of the mirror 38 in the longitudinal direction (first direction) or only at one end, in order to contact multiple points on both the front and back surfaces 381, 382 of the mirror 38 and hold the mirror 38 in a pressed state.

All other aspects of this embodiment are the same as those described in the first to third embodiments.

(Modification)
Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be applied.

For example, in the above embodiment, the mirror 38, which is the optical element 5, is a rectangular parallelepiped. However, the optical element 5 to which the present invention is applicable is not necessarily limited to a rectangular parallelepiped. For example, the shape of the optical element 5 may be a trapezoid or a bow-like curved shape. Also, only one of the front and back surfaces of the optical element 5 may be a bow-like curved shape.

In the above embodiment, a mirror 38 is given as an example of the optical element 5. However, the optical element 5 is not limited to the mirror 38, and may be an elongated lens or an elongated light receiving element.

In the above embodiment, an example was described in which the surface of both the front and back sides of the optical element 5 located in the second direction (Y direction) is an optically functional surface. However, the optically functional surface of the optical element 5 is not limited to the front surface, and may be provided on the back surface, or on both the front and back surfaces. In addition, in the above embodiment, an example was given in which the optically functional surface is a reflective surface, but the optically functional surface is not necessarily limited to a reflective surface, and may be any surface that exhibits some optical function, such as a focusing function, a scattering function, or a refraction function.

In the above embodiment, an example has been described in which the second seat 66 is arranged in contact with one side surface 383 of the mirror 38. However, the second seat 66 may be arranged so as not to contact the one side surface 383 of the mirror 38. In this case, even if the mirror 38 vibrates, no friction occurs between the second seat 66 and the mirror 38, which has the advantage that the transfer function of the vibration system including the mirror 38 and the resonance frequency of the mirror 38 can be further stabilized.

In the above embodiment, the pressing portion 73 is configured from an elastic body having a leaf spring structure, and a pressing force is applied to the mirror 38. However, the manner in which the pressing portion 73 applies a pressing force is not limited to a leaf spring structure, and an elastic body structure such as a coil spring may be used.

In addition, in the above embodiment, an example is given of an optical device 33 having a characteristic configuration of the present invention mounted on an optical writing device 30. However, this is not limited to this, and an optical device having a characteristic configuration of the present invention can also be mounted on an image reading device 40 of a scanner unit 3. For example, the image reading device 40 has mirrors 45, 46, and 47 as described above. Therefore, the structure of the holding unit 51 of the optical device 33 described above may be adopted as a structure for holding the mirrors 45, 46, and 47.

1 Image processing device 5 Optical element 30 Optical writing device 33 Optical device 38 Mirror (optical element)
40 Image reading device 51 (51a, 51b) Holding portion 52 First holding portion 53 Second holding portion 54 Third holding portion 62 First seating portion 64 Steel ball 66 Second seating portion 68 Steel ball 73 Pressing portion

Claims (16)

an optical element having a predetermined length in a first direction, a predetermined thickness in a second direction perpendicular to the first direction, and a predetermined width in a third direction perpendicular to the first direction and the second direction, the predetermined length being longer than the predetermined thickness and the predetermined width;
a first holding portion that contacts both front and back surfaces of the optical element located in the second direction at both ends of the optical element in the first direction and holds the optical element in a state of pressing both the front and back surfaces;
a second holding portion that is disposed at both ends of the optical element in the first direction so as to face two side surfaces of the optical element located in the third direction at an interval wider than the predetermined width, and prevents the optical element from moving in the third direction;
Equipped with
the optical element is held by the first holding portion and the second holding portion in a state where no pressing force is applied in the third direction ,
The first holding portion is
a first seating portion bonded to one of the front and rear surfaces of the optical element;
a pressing portion that is disposed at a position opposite to the first seating portion and is bonded to the other of the front and back surfaces of the optical element to press the optical element toward the first seating portion;
Equipped with
The first seat is constituted by a steel ball,
The optical device according to claim 1, wherein the pressing portion is formed of an elastic body, and presses the optical element toward the first seating portion by the elastic force of the elastic body . the first seating portion is in point contact with one of the front and rear surfaces of the optical element;
The optical device according to claim 1 , wherein the pressing portion is in point contact with the other of the front and back surfaces of the optical element. 3. The optical device according to claim 1 , wherein the first seating portion is disposed at a plurality of positions in the third direction. an optical element having a predetermined length in a first direction, a predetermined thickness in a second direction perpendicular to the first direction, and a predetermined width in a third direction perpendicular to the first direction and the second direction, the predetermined length being longer than the predetermined thickness and the predetermined width;
a first holding portion that contacts both front and back surfaces of the optical element located in the second direction at both ends of the optical element in the first direction and holds the optical element in a state of pressing both the front and back surfaces;
a second holding portion that is disposed at both ends of the optical element in the first direction so as to face two side surfaces of the optical element located in the third direction at an interval wider than the predetermined width, and prevents the optical element from moving in the third direction;
Equipped with
the optical element is held by the first holding portion and the second holding portion in a state where no pressing force is applied in the third direction ,
The optical device according to claim 1, wherein the second holding portion has a pair of protrusions facing each other and capable of making point contact with each of the two side surfaces of the optical element . 5. The optical device according to claim 4 , wherein a tip position of at least one of the pair of protrusions is adjustable in the third direction. an optical element having a predetermined length in a first direction, a predetermined thickness in a second direction perpendicular to the first direction, and a predetermined width in a third direction perpendicular to the first direction and the second direction, the predetermined length being longer than the predetermined thickness and the predetermined width;
a first holding portion that contacts both front and back surfaces of the optical element located in the second direction at both ends of the optical element in the first direction and holds the optical element in a state of pressing both the front and back surfaces;
a second holding portion that is disposed at both ends of the optical element in the first direction so as to face two side surfaces of the optical element located in the third direction at an interval wider than the predetermined width, and prevents the optical element from moving in the third direction;
Equipped with
the optical element is held by the first holding portion and the second holding portion in a state where no pressing force is applied in the third direction ,
The second holding portion is
a second seating portion bonded to one of the two side surfaces of the optical element; and
a fall-off prevention portion disposed at a position spaced a predetermined distance from the other of the two side surfaces of the optical element;
An optical device comprising : 7. The optical device according to claim 6 , wherein the second seating portion has a rigidity higher than that of the fall-off prevention portion and is disposed at a lower position than the fall-off prevention portion. 8. The optical device according to claim 1 , wherein the second holding portions are disposed so as to face each other at positions near the centers of the side surfaces in the second direction. 9. The optical device according to claim 1, wherein the first holding portion and the second holding portion are provided at the same position in the first direction of the optical element. 10. The optical device according to claim 1, wherein the optical element has a thickness in the second direction that is smaller than a width in the third direction. a third holding portion that is disposed so as to face two end faces located in the first direction at a distance wider than a length of the optical element in the first direction, and that prevents the optical element from moving in the first direction;
11. The optical device according to claim 1, further comprising: 12. The optical device according to claim 1, wherein the optical element has a rectangular parallelepiped shape. 13. The optical device according to claim 1, wherein at least one of the front and back surfaces of the optical element is an optically functional surface. 14. The optical device according to claim 13 , wherein the optical function surface of the optical element is a reflecting surface. A light source;
a polarizer for deflecting and scanning the light from the light source;
The optical device according to claim 1 , which is disposed in a traveling direction of light that is deflected and scanned by the polarizer;
Equipped with
An optical writing device, which writes an image by light projected from the optical device. An optical device according to any one of claims 1 to 14 ,
2. An image processing device which reads or writes an image using light projected from the optical device.

Images