JP2801831B2 - 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]

The present invention comprises a lens plate in which a plurality of lenses are linearly arranged and supported at predetermined intervals, and a base plate in which a number of image element arrays are linearly arranged and mounted. An image apparatus in which the lens plate and the base plate are fixed together by a spacer so that each lens and each image element array correspond one-to-one, wherein a lens plate supporting the lens and an image element array are mounted. The thermal expansion coefficient of the placed base plate is made substantially the same, and the thermal expansion coefficient of the spacer is made negative.

[0009]

According to the image apparatus of the present invention, since 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, heat is applied to both the lens plate and the base plate. Even when the voltage is applied, the lens plate and the base plate thermally expand by substantially the same amount, and as a result, no positional displacement occurs between each lens and each image element array. At the same time, since the thermal expansion coefficient of the spacer interposed between the lens plate and the base plate is made negative, the interval (pitch) between adjacent lenses increases with the thermal expansion of the lens plate, so that light is applied to the entire surface of the photoconductor. Irradiation or correcting the inability to form external image information on the entire surface of the image sensor array is corrected by reducing the distance between the lens plate and the base plate. As a result, the entire surface of the photoconductor is irradiated with light, or External image information can be formed on the entire surface of the solid-state imaging device array. Therefore, when this image apparatus is used in an image forming apparatus such as an optical printer head, the center of each lens is always located at the center of the light emitting diode element array, and the light emitted from the light emitting diode elements of each light emitting diode element array Can be satisfactorily irradiated on the entire surface of the photosensitive member, and a clear and accurate latent image can be formed on the photosensitive member.

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. Image can be accurately formed on the entire surface of the device, 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 spacer, and 4 is a light emitting diode element array. And 5 are lenses.

The base plate 1 is made of an electrically insulating material such as a carbon fiber reinforced liquid crystal polymer, 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 adopting, for example, an injection molding method so that the injection flow direction coincides with the arrangement and placement of the light emitting diode element array 4. Have been.

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 includes a light emitting diode element array 4 made of, for example, a carbon fiber reinforced liquid crystal polymer.
Is formed of a material having substantially the same thermal expansion coefficient as that of the base plate 1 on which the lens is mounted, and the thermal expansion coefficient of the lens plate 2 is substantially the same as that of the base plate 1. When the lens plate 2 and the base plate 1 are used as a light source, even if heat is applied to both the lens plate 2 and the base plate 1, the lens plate 2 and the base plate 1 thermally expand by substantially the same amount, and each lens 5 and each light emitting diode element array 4 As a result, the light emitted from each light emitting diode element 4a is accurately and sharply imaged on the surface of the photoconductor 6 through the lens 5,
It is possible to form a high quality latent image 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.

Further, 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 fixed to the spacers 3 so that each light emitting diode element array 4 and each lens 5 are fixed. Are provided so as to correspond one-to-one with a predetermined distance.

The spacer 3 has a first reference surface on its top.
3a has a second reference surface 3b at the bottom, and the spacer 3
Each light emitting diode element array 4 and each lens 5 are fixed by abutting and fixing the outer peripheral portion of the lower surface of the lens plate 2 to the first reference surface 3a of the base plate 1 and the outer peripheral portion of the upper surface of the base plate 1 to the second reference surface 3b of the spacer 3. 1 to 1 with a predetermined distance between
It corresponds to.

The spacer 3 is made of a material having a negative coefficient of thermal expansion, such as an unfilled liquid crystal polymer, so that the distance (pitch) between the adjacent lenses 5 is increased with the thermal expansion of the lens plate 2. Spreads,
Correcting the impossibility of irradiating the light emitted from the light emitting diode element 4a to the entire surface of the photoconductor without gaps by reducing the distance between the lens plate 2 and the base plate 1 and widening the light irradiation area of the lens 5 As a result, the entire surface of the photoconductor 6 is irradiated with light, so that a predetermined latent image can be formed on the photoconductor 6 accurately and clearly.

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 embodiment, and various modifications can be made without departing from the scope of the present invention. For example, in the above embodiment, the base plate 1 and the lens plate 2 Are made of glass fiber reinforced liquid crystal polymer and the spacer 3 is made of unfilled liquid crystal polymer.However, the base plate 1 and the lens plate 2 may be made of any material that has substantially the same coefficient of thermal expansion of both. 3 can be any material having a negative coefficient of thermal expansion.

A light emitting diode element array between and adjacent to the base plate 1 and the lens plate 2
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. Can also be used.

[0029]

According to the image apparatus of the present invention, since the thermal expansion coefficient of the lens plate supporting the lens and the base plate on which the image element array is mounted are substantially the same, both the lens plate and the base plate can be used. Even if heat is applied, the lens plate and the base plate thermally expand by substantially the same amount, and as a result, no positional displacement occurs between each lens and each image element array. At the same time, since the thermal expansion coefficient of the spacer interposed between the lens plate and the base plate is set to be negative, the interval (pitch) between adjacent lenses is widened with the thermal expansion of the lens plate, and light is applied to the entire surface of the photoconductor. Irradiation or correcting the inability to form external image information on the entire surface of the image sensor array is corrected by reducing the distance between the lens plate and the base plate. As a result, the entire surface of the photoconductor is irradiated with light, or External image information can be formed on the entire surface of the solid-state imaging device array. Therefore, when this image apparatus is used in an image forming apparatus such as an optical printer head, the center of each lens is always located at the center of the light emitting diode element array, and the light emitted from the light emitting diode elements of each light emitting diode element array Can be satisfactorily irradiated on the entire surface of the photosensitive member, and a clear and accurate latent image can be formed on the photosensitive member.

When this image device is used for an image reading device such as an image sensor, there is no displacement between each lens and each image element array. Image can be accurately formed on the entire surface of the device, 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.

[Explanation of symbols]

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

Continuation of the front page (51) Int.Cl. ⁶ identification symbol FI H04N 1/028 1/036 (56) References JP-A-5-307140 (JP, A) JP-A-4-336518 (JP, A) JP-A-2-286358 (JP, A) JP-A-2-134260 (JP, A) JP-A-1-264469 (JP, A) JP-A-56-80958 (JP, A) (JP, U) Japanese Utility Model 63-169754 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) B41J 2/44 B41J 2/45 B41J 2/455 G02B 7/02 G02B 27 / 18 H04N 1/028 H04N 1/036 G03G 15/04

Claims (1)

(57) [Claims] A lens plate having a plurality of lenses linearly arranged and supported at predetermined intervals; and a base plate on which a large number of image element arrays are linearly arranged and mounted. An image apparatus in which each lens and each image element array are fixed in a one-to-one correspondence via a spacer, wherein thermal expansion of a lens plate supporting the lens and a base plate on which the image element array is mounted is provided. An image apparatus wherein the coefficients are substantially the same and the thermal expansion coefficient of the spacer is negative.