JP2710910B2 - Imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an optical printer head or an image reading apparatus such as an image sensor.

[0002]

2. Description of the Related Art A conventional image device, for example, an image device used for an image forming apparatus such as an optical printer head, is usually a resin such as polycarbonate having a plurality of lenses linearly arranged and supported on a support at predetermined intervals. Each lens and each LED element array correspond one-to-one with a lens plate made of aluminum oxide and a base plate made of aluminum oxide-based sintered body or glass in which a large number of light-emitting diode element arrays are arranged linearly. The light emitting diodes of each light emitting diode element array are selectively and individually lit according to an external electric signal, and the light emitted by each light emitting diode element is formed into a lens. An image is formed on the surface of an external photoconductor via the photoreceptor to form a latent image on the photoconductor, thereby functioning as an image forming apparatus.

A light emitting diode element array mounted linearly on the base plate generally has 64 light emitting diode elements linearly arranged inside thereof, and a B4 size image forming apparatus. In this case, the light emitting diode element array is mounted on the base plate such that 32 of the light emitting diode element arrays correspond to the respective lenses on a one-to-one basis.

[0004] In addition, when the respective lenses supported by the lens plate and the respective light emitting diode element arrays mounted on the base plate are displaced from each other, the image formed on the photoreceptor surface becomes blurred, white stripes or black. Since it is impossible to form a clear and accurate latent image due to generation of stripes and the like, each lens and each light emitting diode element array are aligned with extremely high precision.

[0005]

However, in this conventional image apparatus, a lens plate made of a resin such as polycarbonate for supporting a lens and an aluminum oxide sintered body or glass on which a light emitting diode element array is mounted are used. The base plate consists of 1.
9 × 10 ^-5 / ℃, 4.0 ~ 7.5 × 10 ^-6 / ℃, there is a large difference, when this image device is used in the image forming apparatus incorporated, heat is applied to both the lens plate and the base plate This causes the lens plate to expand more thermally than the base plate, resulting in a misalignment between the lens supported by the lens plate and the light emitting diode element array mounted on the base plate, resulting in a clear and accurate photoreceptor surface. A latent image cannot be formed.

In the above conventional example, an image apparatus used for an image forming apparatus such as an optical printer head has been described as an example. However, a solid-state image sensor array (CCD element array) has been described.
Also in an image device used for an image reading device such as an image sensor using the image sensor, the image formation of the external image information on the solid-state image sensor array becomes non-uniform due to a positional shift between the lens and the solid-state image sensor array, There is a disadvantage that it is impossible to generate an accurate electric signal corresponding to the image information in the solid-state imaging device array.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks, and has as its object to accurately irradiate light emitted from a light-emitting diode element onto a photoreceptor surface through a lens, thereby providing a latent image having a high image quality on the photoreceptor. Or an image device capable of accurately forming external image information on a solid-state image sensor array via a lens and generating an accurate electric signal corresponding to the external image information in the solid-state image sensor array Is to provide.

[0008]

According to the present invention, there is provided a lens plate having a plurality of lenses linearly supported on a support at predetermined intervals, a base plate on which a large number of image element arrays are linearly arranged and mounted. Are fixedly mounted side by side so that each lens and each image element array correspond one-to-one, wherein a coefficient of thermal expansion of a lens plate supporting the lens and a base plate on which the image element array is mounted are provided. Are substantially the same, and a central portion of each of the lens plate and the base plate is fixed to a support.

[0009]

According to the image apparatus of the present invention, the coefficient of thermal expansion of the lens plate supporting the lens and the base plate on which the image element array is mounted are made substantially the same, and the center of each of the two is fixed to the support. Therefore, even if heat is applied to both the lens plate and the base plate, the lens plate and the base plate thermally expand by substantially the same amount without being affected by the fixation to the support, and as a result,
No positional deviation occurs between each lens and each image element array. Therefore, when this image device is used in an image forming apparatus such as an optical printer head, the center of each lens can always be located at the center of the light emitting diode element array, whereby the light emitting diode elements of each light emitting diode element array The emitted light satisfactorily irradiates the photoreceptor surface, and a clear and accurate latent image can be formed on the photoreceptor.

When this image device is used in an image reading device such as an image sensor, there is no positional deviation between each lens and each image element array, so that external image information is transferred to the solid-state image sensor array via the lens. And an accurate electric signal corresponding to external image information can be generated in the solid-state imaging device array.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 to 3 show an embodiment in which the image apparatus of the present invention is applied to an optical printer head as an image forming apparatus, wherein 1 is a base plate, 2 is a lens plate, 3 is a support, and 4 is a light emitting diode element. The array, 5 is a lens.

The base plate 1 is made of an electrically insulating material such as glass epoxy resin, and a plurality of light emitting diode element arrays 4 are linearly arranged on the upper surface thereof.

The base plate 1 functions as a support member for supporting the light emitting diode element array 4, and is manufactured by pouring a sol-like epoxy resin into glass fibers, and then thermally curing the epoxy resin. .

The light emitting diode element array 4 arranged and mounted on the base plate 1 comprises a plurality of light emitting diode elements 4a, and the light emitting diode elements 4a selectively emit light individually in response to an external electric signal. Then, the surface of the photoconductor 6 is irradiated with the emitted light to form a latent image for forming an image on the photoconductor 6.

The light emitting diode element 4a is of GaAsP type, Ga
P-based light-emitting diodes are used.For example, in the case of GaAsP-based light-emitting diodes, a GaAs substrate is first heated to a high temperature in a furnace, and AsH ₃ (arsine), PH ₃ (phosphine), and Ga (gallium) are used. ) Is brought into contact with a gas containing an appropriate amount of GaAsP (gallium-arsenide-phosphorus) single crystal on the substrate surface, and then Si ₃ O 4 is grown on the GaAsP single crystal surface.
An N ₄ (silicon nitride) film with a window is deposited, and the window is exposed to a gas of Zn (zinc).
Zn is diffused into a part of the single crystal to form a p-type semiconductor, and pn
It is formed by having a bond.

In the case of a B4 size optical printer head, the number of the light emitting diode elements 4a is 2048 (8 per 1 mm).
Are linearly arranged, and specifically, a light emitting diode element array in which 64 light emitting diode elements 4a are one unit.
By linearly arranging 32 light emitting diodes 4, 2048 light emitting diode elements 4 a are arranged on the base plate 1.

The base plate 1 on which the light emitting diode element array 4 is mounted is provided with a lens plate 2 at a predetermined distance above the base plate 1, and a plurality of holes 2a are formed in the lens plate 2 in a straight line. The lenses 5 are arrayed and fixed so as to cover the holes 2a via an adhesive such as resin.

The lens plate 2 has a plurality of lenses 5
Acts as a support member for supporting the
Reference numeral 2a functions to transmit the light emitted from each light emitting diode element 4a of the light emitting diode element array 4 to the photoconductor 6 side.

The lens plate 2 is made of a material having substantially the same thermal expansion coefficient as that of the base plate 1 on which the light emitting diode element array 4 is mounted, such as glass epoxy resin, for example. Is substantially the same as the coefficient of thermal expansion of the base plate 1, the lens plate 2 and the base plate 1 will not move even when heat is applied to both the lens plate 2 and the base plate 1 when used as the light source of the electrophotographic printer. There is no thermal displacement due to substantially the same amount, and no positional displacement occurs between each lens 5 and each light emitting diode element array 4. As a result, light emitted from each light emitting diode element 4a is exposed through the lens 5. An accurate and clear image is formed on the surface of the photoconductor 6, and a high-quality latent image can be formed on the photoconductor 6.

Each of the lenses 5 supported by the lens plate 2 receives light emitted from each of the light emitting diode elements 4a.
A lens made of a transparent resin such as an acrylic resin or a polycarbonate resin or a transparent inorganic material such as a glass, which has an effect of irradiating six surfaces, is preferably used.

Each of the lenses 5 is linearly bonded to the lens plate 2 at a predetermined interval by bonding a part of the outer surface of the lens 5 to the lens plate 2 via an adhesive such as a resin.

The base plate 1 on which the light emitting diode element array 4 is mounted and the lens plate 2 on which the lens 5 is supported are each fixed to a pair of supports 3, 3 so that each light emitting diode element array is fixed. Four
And each lens 5 are provided so as to correspond one-to-one with a predetermined distance therebetween.

The pair of supports 3, 1
The reference surface 3a of the support 3 has a second reference surface 3b at the bottom, the outer peripheral portion of the lower surface of the lens plate 2 is provided on the first reference surface 3a of the support 3, and the base plate is provided on the second reference surface 3b of the support 3. By fixing the outer peripheral portion of the upper surface of the light emitting diode 1 in contact with each other, each light emitting diode element array 4 and each lens 5 are separated from each other by a predetermined distance.
It corresponds to one-to-one.

The pair of supports 3, 3 are made of, for example, the same material as the base plate 1 and the lens plate 2, specifically, a glass epoxy resin.

As shown in FIG. 3, the base plate 1 and the lens plate 2 are fixed to the pair of supports 3 and 3 only by the center of each of the base plate 1 and the lens plate 2. Alternatively, it is performed by bonding through an acrylic adhesive 7a, and both ends are free. Therefore, even when heat is applied to the pair of supports 3, 3 and the base plate 1 and the lens plate 2, the lens plate 2 and the base plate 1 are heated by substantially the same amount without being affected by the fixation to the supports 3, 3. There is no expansion and no displacement occurs between each lens 5 and each image element array 3. Therefore, in this optical printer head, the center of each lens 5 can always be positioned at the center of the light emitting diode element array 4, and as a result, the light emitted from the light emitting diode element 4a of each light emitting diode element array 4 emits light on the surface of the photoconductor 6. Well-irradiated photoreceptor
6, it is possible to form a clear and accurate latent image.

The fixing of the base plate 1 and the lens plate 2 to the pair of supports 3, 3 is not limited to the adhesive fixing using an epoxy or acrylic adhesive 7a, but uses screws or the like. A mechanical fixing method may be employed.

The base plate 1 and the lens plate 2 fixed to the pair of supports 3, 3 are further supported at both ends by a soft adhesive 7b having an elastic modulus of 35 kgf / cm ² or more.
By bonding the base plate 1 and the lens plate 2 to each other, the base plate 1 and the lens plate 2 can be firmly fixed by the pair of supports 3 and 3 without hindering the thermal expansion of the base plate 1 and the lens plate 2. Therefore, the light emitting diode element array
When fixing the base plate 1 on which the base plate 4 is mounted and the lens plate 2 supporting the lens 5 to the pair of supports 3, 3, the central portions of the base plate 1 and the lens plate 2 are bonded by epoxy or acrylic bonding. It is preferable that both ends are fixed with the agent 7a with a soft adhesive having an elastic modulus of 35 kgf / cm ² or more, specifically, an adhesive 7b made of silicone rubber or epoxy mixed with rubber.

Thus, according to the imaging apparatus of the present invention, a predetermined power is applied to each of the light emitting diode elements 4a of the light emitting diode element array 4 linearly mounted on the base plate 1, and each of the light emitting diode elements 4a is turned on. Individually and selectively emit light, and the light emitted by each of the light emitting diode elements 4a is imaged on a surface of an external photoconductor 6 via a lens 5;
By forming a predetermined latent image on the photoconductor 6, it functions as an image forming apparatus.

It should be noted that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention. For example, in the above-described embodiment, the base plate 1 and the lens plate 2 Both were made of glass epoxy resin, but the base plate 1 and lens plate 2
Any material can be used as long as the material has substantially the same thermal expansion coefficient as the base plate.
Lens plate when 1 is made of glass epoxy resin
2 is made of glass epoxy resin, glass fiber reinforced nylon, glass fiber reinforced polyphenylene sulfide resin, glass fiber reinforced acrylonitrile butadiene styrene copolymer, or a material obtained by selectively mixing at least two of these materials. Is also good.

A light emitting diode element array between the base plate 1 and the lens plate 2 and adjacent thereto
If a light-shielding plate 8 is provided between the light-emitting diodes 4, light emitted from the light-emitting diode elements 4a of each light-emitting diode element array 4 will leak to the adjacent light-emitting diode element array 4 even if the light is leaked by the light-shielding plate 8. As a result, the light emitted from the light emitting diode elements 4a of each light emitting diode element array 4 is radiated and formed on the photosensitive member 6 only through the corresponding lens 5 on a one-to-one basis, and is unnecessary for the photosensitive member 6. There is no bleeding or the like due to the irradiation of extraordinary light, and an extremely clear latent image can be formed. Therefore, the base plate
It is preferable that a light-shielding plate 8 is arranged between the light-emitting diode element array 4 and the light-emitting diode element array 4 between the lens plate 1 and the lens plate 2.

Further, in the above-described embodiment, the case where the present invention is applied to an image forming apparatus such as an optical printer head has been described as an example. However, the light emitting diode element array is changed to a solid-state image pickup element array to be used in an image reading apparatus such as an image sensor. Can also be used.

[0032]

According to the image apparatus of the present invention, the coefficient of thermal expansion of the lens plate supporting the lens and the base plate on which the image element array is mounted are substantially the same, and the center of each of the two is supported by the support. Therefore, even if heat is applied to both the lens plate and the base plate, the lens plate and the base plate thermally expand by substantially the same amount without being affected by the fixation to the support. There is no displacement between each image element array. Therefore, when this image device is used in an image forming apparatus such as an optical printer head, the center of each lens can always be located at the center of the light emitting diode element array, whereby the light emitting diode elements of each light emitting diode element array The emitted light satisfactorily irradiates the photoreceptor surface, and a clear and accurate latent image can be formed on the photoreceptor.

When this image device is used in an image reading device such as an image sensor, there is no displacement between each lens and each image element array, so that external image information is transferred to the solid-state image sensor array via the lens. And an accurate electric signal corresponding to external image information can be generated in the solid-state imaging device array.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an embodiment in which an image forming apparatus according to the present invention is applied to an optical printer head as an image forming apparatus.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is a plan view of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Base plate 2 ... Lens plate 3 ... Support 4 ... Light emitting diode element array 4a ... Light emitting diode element 5 ... Lens 7a ... Adhesive

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H04N 1/04

Claims (2)

(57) [Claims] 1. A lens plate in which a plurality of lenses are linearly arranged and supported on a support at predetermined intervals, and a base plate on which a large number of image element arrays are linearly arranged and mounted, each lens and each image element. An image apparatus in which an array and an array are fixed side by side so as to correspond one-to-one, wherein a lens plate supporting the lens and a base plate on which the image element array is mounted have substantially the same thermal expansion coefficient. An image apparatus, wherein a central portion of each of a lens plate and a base plate is fixed to a support. 2. The image forming apparatus according to claim 1, wherein each end of the lens plate supporting the lens and the base plate on which the image element array is mounted is bonded to the support via a soft adhesive. An imaging device according to any of the preceding claims.