JP2002019182A - Exposing unit and imaging apparatus comprising it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the quantity of light of an exposing unit comprising light emitting elements arranged in array. SOLUTION: The exposing unit comprises a light emitting element substrate where an array of a plurality of light emitting elements is formed on the same basic material, and a rod lens array for focusing light beam emitted from each light emitting element on the surface of an image carrying body wherein the light emitting element substrate is made of a transparent and insulating basic material and a microlens array comprising a plurality of microlenses is arranged on the transparent and insulating basic material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to monochrome images and / or monochrome images.
Also, the present invention relates to an exposure apparatus used as an exposure system of an image forming apparatus such as a printer, a facsimile, and a copying machine that forms a color image, and an image forming apparatus equipped with the exposure apparatus.

[0002]

2. Description of the Related Art Conventionally, many image forming apparatuses such as a printer, a facsimile, a digital copying machine, and the like use an electrophotographic system, and include an image output from an external computer or an image reading system. As an exposure system for forming a latent image corresponding to a signal on a photoconductor, there is an exposure system using a light source using an array of light emitting elements such as light emitting diodes. Such an exposure apparatus is small and can easily constitute a quiet image forming apparatus.

[0003] Here, the light emitting element is composed of a light emitting diode or the like, which emits diffused light from a certain point or a certain surface. It is necessary to form an image of the diffused light emitted from the light emitting element on each minute spot. Therefore, the exposure apparatus is provided with an imaging element array represented by a rod lens array so as to form a good spot. For this reason, the relative positional relationship between the light emitting element and the imaging element is set. Are configured to have high positional accuracy.

[0004]

On the other hand, there is a demand for faster image formation. Therefore, in general, there is a problem that the light transmission rate of the rod lens array is low due to a low aperture ratio of each rod lens, and in order to solve such a problem, the exposure apparatus emits light and forms an image on a photoconductor. There is a need to increase the amount of light.

Accordingly, an object of the present invention is to increase the amount of light of an exposure apparatus in which light emitting elements are arrayed.

Another object of the present invention is to increase the speed of image formation in an image forming apparatus using the exposure apparatus of the present invention.

[0007]

SUMMARY OF THE INVENTION In view of the above problems, an exposure apparatus according to the present invention comprises a light emitting element substrate having a plurality of light emitting elements arranged on the same base material, and a light emitting element substrate comprising: A rod lens array for imaging a divergent light beam on an image carrier, wherein the light emitting element substrate is provided with the light emitting element rows on a transparent insulating base material, and the transparent insulating base material Has a microlens array composed of a plurality of microlenses.

[0008] Further, the light emitting element array may be an organic LED array comprising at least a transparent conductive layer, an organic layer, and electrodes on the transparent insulating substrate.

[0009] Further, on the transparent insulating substrate, the organic LED array section is composed of at least a translucent reflective layer, a transparent conductive layer, an organic layer, and an electrode, and a space between the translucent reflective layer and the electrode. The configuration may be a micro optical resonator.

[0010] The microlenses of the microlens array may be in one-to-one correspondence with each light emitting element.

Further, the opening area of the microlens of the microlens array may be larger than the area of the light emitting portion of each light emitting element.

Further, the microlenses of the microlens array may be formed by ion-exchanging a portion of the transparent insulating substrate corresponding to each light emitting element.

Further, the microlenses of the microlens array may have a convex lens shape corresponding to each light emitting element.

The microlenses of the microlens array may be formed on the same surface of the transparent insulating substrate as the surface on which the light emitting element rows are formed.

Further, the microlens may be formed on a surface of the transparent insulating substrate opposite to a surface on which the light emitting element rows are formed.

[Operation] In the exposure apparatus of the present invention, the light amount can be increased.

Further, in the image forming apparatus using the exposure apparatus of the present invention, the speed of image formation can be increased.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment] The first embodiment of the present invention will be described below.
Will be described with reference to FIGS. 1 to 5.

First, an overall configuration of an exposure apparatus according to the present invention will be schematically described with reference to FIGS. FIG. 1 shows an exposure apparatus 3
FIG. 2 is a cross-sectional view of a photosensitive drum 2 which is an image carrier to be exposed by an exposure device 30. FIG. 2 is a perspective view showing an organic LED array section of the present embodiment, and FIG. 3 is a view for explaining a rod lens array.

In FIG. 1, the organic LED array section 4 is provided with a light emitting element array section 4a in which a plurality of light emitting sections are arranged substantially linearly in a direction perpendicular to the paper surface. The configuration of the light emitting element array 4a will be described later. The row direction of the light emitting element array 4a is parallel to the rotation axis of the columnar photosensitive drum 2, and a number of rod lenses are provided between the light emitting element array 4a and the photosensitive drum 2. There is a rod lens array 3 arranged substantially parallel to the row direction of the upper light emitting element row section 4a.
Here, the luminous flux emitted from the light emitting element array portion 4a is:
The light is emitted to the rod lens array 3 side. With such a configuration, the width of the exposure apparatus, that is, the width in the direction orthogonal to the long direction can be reduced. Further, inside the organic LED array section 4, there are a number of microlenses 1122 manufactured by, for example, an ion exchange method corresponding to one light emitting element, for example, one-to-one. Alternatively, a microlens may be provided such that a plurality of microlenses correspond to one light emitting element, or a plurality of microlenses may be provided such that a plurality of light emitting elements correspond to one microlens. Is also good.

Further, as shown in FIG. 3, the rod lens array 3 is formed by arranging a plurality of cylindrical rod lenses 300 in two rows. The two rows are arranged in order to increase the amount of light transmitted.

In the exposure apparatus 30, on the organic LED array section 4, a driver section (not shown) for driving each light emitting element is formed in addition to the light emitting element row section 4a. In order to protect the light emitting element array section 4a from external moisture and the like, the sealing section 51 is provided on the light emitting element array section 4a side of the organic LED array section 4 so as to also protect the electric drive section. The rod lens array 3 is adhered to a cover 6 for preventing light from leaking.
The cover 6 and the substrate-side holding member 52 are sandwiched by the leaf spring member 53 while sandwiching the EL element substrate 4. The area A between the array section 4 and the rod lens array 3 is protected so that dust does not invade as required, that is, the cover 6 is fixed in contact with the rod lens array 3.

Further, as shown in FIG. 4, the exposure device 30 is incorporated in the image forming apparatus as an exposure device.

Here, the operation will be described with reference to FIG. 4 by taking a copying machine as an example of an image forming apparatus in which the exposure apparatus of the present embodiment is incorporated.

A document placed on the document table 24 is read by a reading system 95 and converted into image data. On the other hand, the recording material 80 is fed to the feeding rollers 13 and 14 in the main body.
Alternatively, the recording material 80 is fed from the outside of the main body via the feeding roller 15, and when the position of the registration rollers 16a and 16b is reached, the leading end position of the recording material 80 is detected by a sensor (not shown). 16b. On the other hand, according to the image data from the exposure device 30, the charging of the image carrier (photoconductor) 2 rotating in the direction of the arrow in the drawing is performed by the charger 17 in advance, and the image carrier 2 is subsequently exposed. An electrostatic latent image is formed on the image carrier 2. According to this electrostatic latent image, the developing device 18
, A developing material (not shown) is applied to the image carrier 2. Then, at the same time that the image carrier 2 to which the developing material is applied rotates to the position on the transfer device 19, the recording material 80 also reaches the transfer device 19, and the developing material is transferred onto the recording material 80 by the transfer device 19. Transcribed. As a result, the recording material 80 is
And reaches the fixing devices 22a and 22b, the transferred developer is fixed on the recording material 80, and is discharged to the tray 23 to complete the image formation.

Here, the organic LED which is the light emitting part of the present invention
The array unit will be described with reference to FIGS.

FIG. 2 is a perspective view including a cross section of the organic LED array section of the present embodiment.

As described above, the glass substrate 1101
A microlens 1122 is formed on a portion corresponding to each light emitting element by an ion exchange method, and a translucent reflective layer 1177 composed of a plurality of layers is formed on the micro lens 1122 on the portion described in FIG. Electrode 1102, hole transport layer 1103, electron transport layer 1104, and cathode 110
5 are stacked from the glass substrate 1101 side.

First, referring to FIG.
2 will be described.

In this embodiment, a soda-lime glass substrate is used as the substrate. Both surfaces of the glass substrate 1101 are sufficiently washed.

Next, the entire glass substrate is masked with an ion-impermeable film (not shown) such as Ti. 30 μm diameter of Ti on ion diffusion surface by photolithographic etching
m, an opening row having a center interval of 80 μm is formed.

The substrate is subjected to TlNO for ion exchange.
₃ and KNO ₃ immersed in a molten salt, with a diameter of approximately 70 μm
Is formed.

Here, examples of the molten salt used for the ion exchange treatment for increasing the refractive index include nitrates such as Ag ⁺ and Tl ⁺ and sulfates.

The refractive index distribution of the micro lens 1122 may be formed in several stages.

Next, a method of forming the translucent reflective layer 1177 on the glass substrate 1101 constituting the optical resonator structure will be described with reference to FIG.

Micro lens 1 on glass substrate 1101
A translucent reflective layer is formed on the surface on which the surface 122 is formed by sputtering to form an SiO ₂ layer 1171 and a TiO ₂ layer 1172.
Are sequentially laminated, and a total of four layers are laminated. These four layers are the above-mentioned translucent reflection film 1177. The thickness of one layer of SiO ₂ is 93 nm, and the thickness of one layer of TiO ₂ is 59 nm.
It is.

Next, as an anode (transparent electrode) 1102, an IT
O is formed. An ITO is formed to a thickness of 60 nm by sputtering with a metal mask having a line width of 50 μm and a pitch of 80 μm on the translucent reflective layer.

Next, as the hole transport layer 1103, N, N '
-Bis (3-methylphenyl) -N, N'-diphenyl- (1,1'-biphenyl) -4,4'-diamine (hereinafter referred to as TPD) as an electron transport layer 1104 in tris (8-
(Quinolyl) aluminum (Alq ₃ ) is sequentially deposited by a vacuum deposition method. Here, the film thicknesses of TPD and Alq ₃ are 40 nm and 50 nm, respectively.

The degree of vacuum at the time of vapor deposition was 2 × 10^-6~ 3x
10^-6Torr (= 2.66 × 10 ^-Four~ 3.99 × 10
^-FourPa), the film forming speed is 0.2 to 0.3 nm / s.
did.

Lastly, a metal mask having a line width of 40 μm was placed so as to be orthogonal to the ITO,
And Ag are co-deposited at a deposition rate ratio of 10: 1 to obtain Mg / Ag
Form a 200 nm alloy of 10/1. At this time, the film forming speed was 1 nm / s.

The opening area of the microlens is made larger than the area of the light emitting portion so that emitted light can be obtained efficiently.

It is desirable that the anode material of the organic LED has a large work function. For example, tin oxide, gold, platinum, palladium, selenium, iridium, copper iodide, or the like is used in addition to ITO used in the present embodiment. it can.

On the other hand, it is desirable that the cathode material has a small work function. In addition to Mg / Ag used in the present embodiment, for example, Mg, Al, Li, In, or an alloy thereof can be used.

As for the hole transport layer, an organic material represented by Chemical Formulas 1 to 5 can be used in addition to TPD.

[0046]

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[0047]

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[0048]

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[0049]

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[0050]

Embedded image Further, not only an organic material but also an inorganic material may be used. As a material to be used, an amorphous material, for example, amorphous silicon (a-Si), amorphous silicon carbide a-SiC, or the like can be given. If necessary, at least one of hydrogen, oxygen, and nitrogen may be appropriately added to these amorphous materials.

As the electron transport layer, in addition to Alq ₃ ,
To 9 can be used.

[0052]

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[0053]

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[0054]

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[0055]

Embedded image Further, a dopant dye as shown in Table 10 can be doped into the electron transporting layer or the hole transporting layer.

[0056]

Embedded image The material constituting the translucent reflective layer, the film thickness, the number of layers, the transparent electrode, the film thickness of the organic layer, etc. are not limited to the configuration of the present embodiment, and a spectrum having sensitivity with the photosensitive drum used can be obtained. It is desirable to optimize as follows.

When a DC voltage is applied to this organic LED array with the ITO electrode plus and the Mg / Ag electrode minus, green light is emitted from the intersection of the ITO electrode and the Mg / Ag electrode.

By connecting the driving driver to the organic LED array section thus obtained as described above, it is possible to use the exposure apparatus as described above to output a good image.

This can have an optical resonator structure with a semi-transparent mirror. By using such an organic LED array, the diffusion of light is suppressed, the spread of an exposure spot is reduced, and at the same time, the light is exposed by a microlens. This is because it has become possible to form an image on the drum. Also, the output of the peak wavelength can be strengthened at the same time as the half width of the emission wavelength is narrowed, and the amount of light incident on the rod lens array can be increased by the microlens from the state without the microlens. Can be used more efficiently.

In this embodiment, an exposure apparatus of 300 dpi was prepared, but a light emitting point of an arbitrary size can be obtained by changing the electrode width.
An exposure apparatus of i can also be created.

As described above, in the exposure apparatus according to the first embodiment of the present invention, the amount of emitted light can be efficiently used by increasing the amount of light as the exposure apparatus and narrowing the wavelength width. Further, the image forming apparatus using the exposure apparatus of the present embodiment can increase the amount of light of the exposure apparatus and increase the speed of latent image formation by utilizing the efficiency of the amount of light, and thus the speed of image formation itself.

[Second Embodiment] The second embodiment of the present invention will be described below.
The embodiment will be described with reference to FIG.

The exposure apparatus of this embodiment is different from the first embodiment in that the organic LED array section is in close contact with the rod lens array. The used image forming apparatus is the same as that of the first embodiment, and the description is omitted.

FIG. 6 is a cross-sectional view of the exposure device 230 and the photosensitive drum 202 as an image carrier to which the exposure device 230 exposes.

In FIG. 6, the organic LED array section 204 is provided with a light emitting element array section 204a in which a plurality of light emitting sections are arranged substantially linearly in a direction perpendicular to the paper surface. The light emitting element array section 204a is the same as in the first embodiment. The row direction of the light emitting element array section 204a is parallel to the rotation axis of the columnar photosensitive drum 202, and a number of rod lenses are provided between the light emitting element array section 204a and the photosensitive drum 202 on the organic LED array section 204. The rod lens array 203 similar to the first embodiment is arranged substantially in parallel with the row direction of the light emitting element row portions 204a. Here, the luminous flux emitted from the light emitting element array section 204a is configured to be emitted to the rod lens array 203 side. Also, inside the organic LED array section 204, there are a number of microlenses 1222 manufactured by ion exchange corresponding to the light emitting elements on a one-to-one basis.

In the exposure apparatus 230, an organic LED
On the array section 204, a driver section (not shown) for driving each light emitting element is formed in addition to the light emitting element row section 204a. In order to protect those electric driving units from external moisture, the sealing unit 251 is an organic LED.
It is provided on the light emitting element column portion 204a side of the array. The rod lens array 203 is adhered to a cover 206 for preventing light from leaking, and the rod lens array 203 and the substrate-side holding member 252 are connected to the EL element substrate 20.
4 is sandwiched by the leaf spring member 253. Thus, the organic LED array unit 204 and the rod lens array 20
3 are tightly fixed.

Here, the light emitted from the light emitting element array section 204a is first condensed by the micro lens 1222 inside the organic LED array section, and passes from the micro lens 1222 through the transparent substrate section of the organic LED array section to the rod lens array 203. Emitted to the side. And the rod lens array 20
3 forms an image on the photosensitive drum 202.

By adopting such a configuration, in addition to the effects of the first embodiment, it is possible to further simplify the configuration of the exposure apparatus, to further reduce the size of the exposure apparatus, and to further easily assemble the exposure apparatus.

[Third Embodiment] A third embodiment of the present invention will be described with reference to FIG.

In this embodiment, in the exposure apparatuses of the first and second embodiments, only the organic LED array section is changed, and other explanations are omitted.

FIG. 7 is a sectional view of the organic LED array portion of the present embodiment.

A micro lens 2122 having a convex lens shape is formed on a portion corresponding to each light emitting element on a translucent reflective layer 2177 provided on a glass substrate 2101, and a transparent electrode 2102 and a hole are formed thereon. Transport layer 210
3. Electron transport layer 2104 also serving as light emitting layer, and cathode 2
Reference numeral 105 denotes an organic LED array unit which is stacked with a curvature caused by the curvature of the curved surface of the microlens.

First, a method of forming the micro lens 2122 on the glass substrate 2101 will be described.

As a material for forming a lens, there are ordinary ultraviolet and far ultraviolet resists, and in particular, positive type deep ultraviolet resists such as polymethyl methacrylate, PMIPK, polyglycylmethyl acrylate and phenol novolak. However, it is desirable because it softens at a relatively low temperature and easily forms a condensing lens shape.

The above-mentioned photoresist is laminated on the glass substrate 2101 by a method such as coating or the like, and the photoresist layer is patterned by a photolithography method such as a lift-off method or a dry etching method such that the diameter is 70 μm and the center interval is 80 μm. Patterning is performed using a forming method.

The patterned photoresist is softened and fluidized by annealing to form an arc-shaped microlens 2122.

The translucent reflective layer 2177 was formed with the same configuration by sputtering under the same conditions as in the first embodiment.

Further, an ITO is formed to a thickness of 60 nm by a sputtering method so as to correspond to the microlens 2122 with a metal mask having a line width of 50 μm and a pitch of 80 μm.

Next, similarly to the first embodiment, the hole transport layer 2
TPD as 103 and Al as the electron transport layer 2104
sequentially deposited by vacuum deposition q _3.

The degree of vacuum at the time of vapor deposition was 2 × 10^-6~ 3x
10^-6Torr (= 2.66 × 10 ^-Four~ 3.99 × 10
^-FourPa), the film forming speed is 0.2 to 0.3 nm / s.
did.

Lastly, a metal mask having a line width of 40 μm was placed so as to be perpendicular to the ITO, and Mg was used as the cathode 2105.
And Ag are co-deposited at a deposition rate ratio of 10: 1 to obtain Mg / Ag
Form a 200 nm alloy of 10/1. At this time, the film forming speed was 1 nm / s.

By connecting a driving driver to the organic LED array thus obtained as in the first embodiment, the organic LED array can be used as an exposure apparatus for electrophotography.
The state of light emission is the same as in the first embodiment.

The microlenses on the substrate are not limited to those described in the embodiment, but may be any microlenses that can collect light emitted from the organic LED.

The substrate is not limited to glass, but may be an organic LED such as a resin film, a micro lens, or the like.
Any substrate may be used as long as the translucent reflective layer can be formed on the surface.

As described above, by providing the organic LED array with the microlens and the optical resonator structure using the photolithography method, an optical printer head which can be formed in a short time and which can obtain a high-definition image with low power can be realized. It has become possible.

[Fourth Embodiment] A fourth embodiment of the present invention will be described with reference to FIGS.

In this embodiment, in the exposure apparatuses of the first and second embodiments, only the organic LED array section is changed, and other explanations are omitted.

FIG. 8 is a sectional view of the organic LED array portion of the present embodiment.

A micro lens 312 having a convex lens shape at a portion corresponding to each light emitting element on a glass substrate 3101
2 is formed, and a semitransparent reflective layer 317 is formed on the surface of the glass substrate 3101 opposite to the microlens 3122.
7, a transparent electrode 3102, a hole transport layer 3103, an electron transport layer 3104 also serving as a light emitting layer, and a cathode 3105.

First, a method of forming the micro lens 3122 on the glass substrate 3102 will be described with reference to FIG.

The diameter of the opening of the microlens 3122 is determined by a replica method (a method in which a lens is formed from a resin such as glass or acrylic using a mold made of metal or resin and transferred from the mold onto glass). An array with 75 μm and a center interval of 80 μm is formed. A glass substrate having a thickness larger than the focal length of the microlens was used. This is to obtain the light amount efficiently.

On the surface opposite to the surface on which the microlenses are formed, a translucent reflection layer is formed as in the first embodiment.

Next, a metal mask having a line width of 50 μm and a pitch of 80 μm is put thereon so as to correspond to the microlenses 3122, and ITO is sputtered to a thickness of 60 nm.
Form.

Next, as in the first embodiment, the hole transport layer 3
TPD as 103 and Al as the electron transport layer 3104
sequentially deposited by vacuum deposition q _3.

Lastly, a metal mask having a line width of 40 μm was placed so as to be perpendicular to the ITO, and Mg was used as the cathode 3105.
And Ag are co-deposited at a deposition rate ratio of 10: 1 to obtain Mg / Ag
Form a 200 nm alloy of 10/1. At this time, the film forming speed was 1 nm / s.

By connecting a driving driver to the organic LED array thus obtained in the same manner as in the first embodiment, it can be used as an exposure apparatus for electrophotography.
The state of light emission was the same as in the first embodiment.

The microlenses on the substrate are not limited to those described in the embodiment, and may be any microlenses that can collect light emitted from the organic LED.

The substrate is not limited to glass, but may be an organic LED such as a resin film, a micro lens, or the like.
Any substrate may be used as long as the translucent reflective layer can be formed on the surface.

As described above, by providing the organic LED array with the microlens and the optical resonator structure by the replica method, it is possible to realize an optical printer head capable of forming a simpler, shorter-time, lower-power and higher-definition image. It has become possible.

[0100]

As described above, in the exposure apparatus of the present invention, the light amount can be increased.

Further, by using the exposure apparatus of the present invention in an image forming apparatus, the speed of image formation can be increased.

[Brief description of the drawings]

FIG. 1 is a sectional view of an exposure apparatus and an image carrier according to a first embodiment of the present invention.

FIG. 2 is a perspective view of the organic LED array according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a rod lens array used in the first embodiment of the present invention.

FIG. 4 is a diagram illustrating an example of an image forming apparatus incorporating the exposure apparatus according to the first embodiment of the present invention.

FIG. 5 is a drawing showing a manufacturing process of the organic LED array according to the first embodiment of the present invention.

FIG. 6 is a sectional view of an exposure apparatus and an image carrier according to a second embodiment of the present invention.

FIG. 7 is a perspective view of an organic LED array according to a third embodiment of the present invention.

FIG. 8 is a perspective view of an organic LED array according to a fourth embodiment of the present invention.

FIG. 9 is a diagram illustrating a process of producing an organic LED array according to a fifth embodiment of the present invention.

[Explanation of symbols]

2,202 Image carrier 3,203 Rod lens array 4,204 Organic LED array section 1102, 2102, 3102 Transparent electrode (anode) 1103, 2103, 3103 Hole transport layer 1104, 2104, 3104 Electron transport layer 1105, 2105 3105 Metal electrode (cathode) 1177, 2177, 3177 Translucent reflective layer 1122, 1222, 2122, 3122, 4122
Micro lens part

Claims (10)

[Claims] 1. A light-emitting element substrate in which a plurality of light-emitting elements are arranged on the same base material and a rod lens array that forms a light beam emitted from each light-emitting element on an image carrier. Wherein the light-emitting element substrate is a transparent insulating substrate, and the transparent insulating substrate has a microlens array including a plurality of microlenses. 2. The exposure apparatus according to claim 1, wherein the light-emitting element array is an organic LED array composed of at least a transparent conductive layer, an organic layer, and electrodes on the transparent insulating substrate. 3. The organic LED array section is composed of at least a translucent reflective layer, a transparent conductive layer, an organic layer, and an electrode on the transparent insulating substrate, and is provided between the translucent reflective layer and the electrode. 3. The exposure apparatus according to claim 2, wherein the configuration functions as a micro optical resonator. 4. The exposure apparatus according to claim 1, wherein the microlenses of the microlens array have a one-to-one correspondence with each light emitting element. 5. The exposure apparatus according to claim 1, wherein an opening area of the micro lens of the micro lens array is larger than an area of a light emitting unit of each light emitting element. 6. The microlens of the microlens array is formed by ion-exchanging a portion of the transparent insulating substrate corresponding to each light emitting element. The exposure apparatus according to any one of the above items. 7. The exposure apparatus according to claim 1, wherein the microlenses of the microlens array are microlenses having a convex lens shape corresponding to each light emitting element. 8. The microlens of the microlens array is formed on the same surface of the transparent insulating substrate as the surface on which the light emitting element rows are formed. The exposure apparatus according to any one of the above items. 9. The transparent lens according to claim 1, wherein the microlenses are formed on a surface of the transparent insulating substrate opposite to a surface on which the light emitting element rows are formed. Exposure apparatus according to Item. 10. The light source according to claim 1, wherein the light source is arranged so that an arrangement direction of the image carrier and the light emitting element array is a direction orthogonal to a rotation direction of the image carrier.
The light beam emitted from the light emitting element array is imaged by the rod lens array, and the imaged light beam is exposed on the image carrier to be visualized. Electrophotographic image forming apparatus.