CN100366433C - Light source of image writing device - Google Patents

Abstract

An image forming apparatus includes a light source provided with a converting means for converting the advancing direction of light emitted from the light source, whereby the direction in which the light source is disposed can be determined regardless of a direction in which light is emitted. The advancing direction of the light emitted from a light emitting element is converted into a direction in which the light transmitting means can transmit the light, so that the luminous intensity on the photosensitive drum can be increased. It is designed so as to increase a light emitting area of the light emitting element and condense the light emitted therefrom, in result the luminous flux density can be improved. The light emitting element applies a flat luminous unit, which is combined with a light transmitting means in one optical piece.

Description

Light source of image writing device

technical field

The invention relates to a light source of an image writing device and a manufacturing method of the light source.

Background technique

In the color printer (hereinafter referred to as the printer) 100, from the viewpoint of high-speed printing, there are four visible colors that can print Y (yellow) M (magenta) C (cyan) B (black) in parallel as shown in FIG. 1 . Like the printing method called serial method. In order to form the above-mentioned 4-color visible image in parallel in the printer 100 adopting the tandem method, the writing mechanism 110 composed of the static electricity remover 105 shown in FIG. 100 sets 4 each.

The paper 120 inserted into the tray 101 shown in FIG. 1 is sent to the conveyance path 103 inside the printer 100 by the conveyance roller 102 . In synchronization with conveyance of the paper 120 , latent images are formed on the photosensitive drums 106 of each color by the writing light emitted from the light source 200 , and visible images are formed by the developing device 108 .

The paper 120 transfers the visible image formed on each photosensitive drum 106 in the transport path 103 , and after the visible image is fixed by the fuser 109 , it is output from the printer 100 .

The light source 200 has a substrate 601 elongated in the main scanning direction as shown in FIG. 3 , and a plurality of light emitting elements 8 including LEDs (light emitting diodes, etc.) are formed on the substrate 601 along the main scanning direction. The light emitting element 8 emits light A in a direction perpendicular to the substrate 601 . As shown in FIG. 3 , the light beam A forms an image on the photosensitive drum 106 through the light transmission unit 310 constituting the light source 200 such as a rod lens and a fiber lens to form a latent image.

In order to easily form a sharp latent image on the photosensitive drum 106, the aperture angle of the light transmission unit 310 is reduced to keep the depth of focus deep.

Contents of the invention

The substrate 601 is arranged as shown in FIG. 3 so that the short side is parallel to the sub-scanning direction (perpendicular to the axis of the photosensitive drum 106), and the surface on which the light-emitting element 8 is formed faces the photosensitive drum 106, so that the light beam A is emitted toward the photosensitive drum 106. .

In order for the light source 200 to output the light emission intensity necessary for forming a latent image, the light emitting element 8 needs to have a certain size. In addition, components such as a driver for causing the light emitting element 8 to emit light must be arranged on the substrate 601 . For these reasons, the short side of the substrate 601 needs to be a certain length.

However, as described above, if the short side of the substrate 601 is parallel to the sub-scanning direction, and the surface on which the light-emitting element 8 is formed is arranged to face the photosensitive drum 106, when the short side of the substrate 601 is long, the writing speed of each color can be reduced. The sub-scanning direction of the mechanism 110 becomes longer accordingly.

In the tandem printer 100, since the four-color writing mechanism 110 is arranged in series along the sub-scanning direction, even if the length of the writing mechanism 110 in the sub-scanning direction becomes slightly longer, the overall size of the printer 100 is large. more.

In addition, in recent years, laser printers have been required to print high-resolution images. In order to print a high-resolution image, of course, the resolution in the sub-scanning direction must also be high. For this reason, the number of scans per unit length in the sub-scanning direction increases, and as a result, the printing time becomes longer. In order to print a high-resolution image in a short time, the exposure time per one sub-scanning line may be shortened, but the exposure amount required for forming a latent image on the photosensitive drum 106 cannot be obtained in this way.

In addition, in order to print a high-resolution image on an electrophotographic printer, it is necessary to arrange a plurality of light emitting elements 8 at reduced intervals in the sub-scanning direction. In order to arrange the light emitting elements 8 at narrow intervals, it is necessary to reduce the size of the light emitting elements 8 themselves. If the number of light emitting elements 8 is reduced, the luminance of each light emitting element 8 decreases, and the illuminance on the photosensitive drum 106 decreases.

Therefore, as a method of increasing the exposure amount on the photosensitive drum 106 without reducing the printing speed and without changing the size of the light emitting element 8, there is a method of increasing the aperture angle of the lens constituting the light transmission unit 310 and improving the light transmission efficiency. . However, when the aperture angle is increased, the depth of focus becomes smaller, making it difficult to form a sharp latent image on the photosensitive drum 106 . In addition, as another method, there is a method of increasing the luminance of the light-emitting element 8 by applying a large electric field to the light-emitting element 8, but when a large electric field is applied to the light-emitting element 8, not only the light-emitting life of the light-emitting element 8 is shortened, but also Power consumption also increases.

Accordingly, an object of the present invention is to provide a light source for an image writing device capable of forming a high-resolution latent image without hindering downsizing of the printer and having a long luminescent life, and a method for manufacturing the light source.

The present invention proposes a light source for an image writing device. The light source of the image writing device changes the traveling direction of the light source emitted from the light-emitting element, and can irradiate in the normal direction relative to the photosensitive drum regardless of the direction in which the substrate with the light-emitting element is arranged. light.

In order to change the traveling direction of the light, the light source of the image writing device of the present invention has a conversion unit that changes the traveling direction of the light. The conversion unit may be a prism, or a waveguide that internally reflects the light once or more times to change the traveling direction of the light.

With this conversion unit, there is no restriction that the substrate must be arranged such that the short side of the substrate is parallel to the sub-scanning direction and the light-emitting surface that emits light faces the photosensitive drum in order to irradiate light to the photosensitive drum as in the past. Therefore, when the length from the light-emitting surface of the substrate to the top of the sealing glass is shorter than the short side of the substrate (the height of the substrate is low), the height direction of the substrate is parallel to the sub-scanning direction, and the long-side direction of the substrate and the height When the direction-forming surface is arranged to face the photosensitive drum, a short light source in the sub-scanning direction can be realized. Therefore, by arranging the light source in the direction in which the sub-scanning direction becomes shorter, the light source does not interfere with downsizing of the printer.

In addition, in order to improve the light transmission efficiency without increasing the aperture angle, the light source of the image writing device of the present invention has orientation imparting means for imparting orientation to light emitted from the light emitting element. The orientation imparting unit imparts orientation to the light and guides more light into the light transmission unit. The light transmission unit is a fiber optic lens array composed of multiple single lenses. A configuration may be adopted in which one single lens corresponds to one light emitting element such that light emitted from one light emitting element passes through one single lens.

Like this, even if do not use the light transmission unit that aperture angle is big, the light that reaches photosensitive drum through light transmission unit among the light emitted from above-mentioned light-emitting element also increases, so the transmission efficiency of the light between light-emitting element and photosensitive drum improves .

In addition, when there is a light-condensing unit between the light-emitting element and the photosensitive drum, light is transmitted to the photosensitive drum through the light-condensing unit, so that when light with a large cross-sectional area irradiates the photosensitive drum, the cross-sectional area becomes small. Therefore, a latent image can be formed on the photosensitive drum with small pixels using a light-emitting element with a large light-emitting area.

In order to print high-resolution images by electrophotography, it is necessary to arrange a plurality of light emitting elements in a certain section along the main scanning direction, so there is a limitation on the length of the light emitting elements in the main scanning direction. However, there is no limitation on the length in the sub-scanning direction. Therefore, when the light emitted from the light emitting element elongated in the sub-scanning direction is condensed by the condensing unit, light with a high beam density can be obtained. Therefore, when the light emitted from the light emitting element elongated in the sub-scanning direction is condensed by the condensing unit and irradiated to the photosensitive drum, an exposure amount required for forming a latent image can be obtained.

Therefore, in order to obtain the exposure amount required for latent image formation as described above, the aperture angle of the light transmission unit can also be increased, so that the exposure amount required for latent image formation can be obtained while maintaining a large depth of focus.

When a planar light-emitting element is directly formed on the light-transmitting unit, light emitted from the light-emitting element is directly transmitted to the light-transmitting unit without passing through a layer with a low refractive index and no orientation. Therefore, the light rays reach the photosensitive drum substantially without total reflection, and therefore reach the photosensitive drum with sufficient intensity. Therefore, it is not necessary to apply a large electric field in order to increase the luminance of the light emitting element, so a high-resolution latent image can be formed without shortening the luminous lifetime. In addition, there is no need to increase the aperture angle of the light transmission unit in order to form a latent image, so a large depth of focus can be maintained.

In addition, it is also possible to have a configuration in which a plurality of the single-body lenses are associated with one of the light-emitting elements. In this configuration, since the diameter of the single lens is smaller than that of the light emitting element, the light emitting element can be formed regardless of the positional relationship between the light emitting element and the single lens, and thus the manufacture is easy.

In addition, it is also possible to have a configuration in which the light source of the image writing device is provided with a directional unit between the light emitting element and the light transmission unit, and the light transmission unit, the directional unit, and the light transmission unit are formed optically integrally. light emitting element. The directional unit integrally formed with the light-transmitting unit and the light-emitting element has a mesa structure, and the transmission efficiency can be improved by disposing the light-emitting element on the top and bottom of the mesa structure.

The directivity unit may be a waveguide that imparts directivity to light by reflecting light one or more times.

A light source in which a planar light-emitting element is directly formed on a light transmission unit can be manufactured in the following manner. A transparent electrode element is directly formed on the light transmission unit, a light-emitting layer element composed of a planar luminous body is formed on the transparent electrode element, and a metal electrode layer is formed on the light-emitting element.

In addition, when the light transmission unit and the light-emitting element are integrally provided with a directional unit, it is preferable to directly form the directional unit on the light transmission unit, to form a transparent electrode element on the directional unit, and to form a surface composed of a planar luminous body on the transparent element. The light-emitting element is formed on the light-emitting element with a metal electrode element.

Description of drawings

Figure 1 is a schematic diagram of the printer.

Fig. 2 is an enlarged view of the light source part.

Fig. 3 is a schematic diagram of a light source.

4 is a sectional view of a light source and a photosensitive drum using a prism as a conversion unit.

FIG. 5 is a diagram showing a manufacturing process of a light emitting element.

Fig. 6 is an external view of the light transmission unit.

7 is a schematic diagram of a light source and a photosensitive drum of an image writing device.

Fig. 8 is a diagram showing the shape of a waveguide.

Fig. 9 is a sectional view of a light source and a photosensitive drum using a waveguide as a conversion unit.

Fig. 10 is a cross-sectional view of a light source using a waveguide as a conversion unit.

Fig. 11 is a cross-sectional view of a light source using a prism as a conversion unit.

Fig. 12 is a cross-sectional view of a light source using a prism as a conversion unit.

Fig. 13 is a sectional view of a light source and a photosensitive drum using a waveguide as a conversion unit.

Fig. 14 is a cross-sectional view of a light source using a prism as a conversion unit.

Fig. 15 is a cross-sectional view of a light source using a waveguide as a conversion unit.

FIG. 16 is a schematic diagram of a light source and a photosensitive drum of the image writing apparatus of the present invention.

FIG. 17 is a schematic diagram of a transparent substrate on which small protrusions are formed.

Fig. 18 is a diagram showing the trajectory of light emitted from a light emitting element.

FIG. 19 is a diagram illustrating a manufacturing process of a light emitting element.

FIG. 20 is a diagram showing a manufacturing process of small protrusions using anisotropic etching.

Fig. 21 is an overall view of a pellet and a light transmission unit.

Fig. 22 is a view showing a manufacturing process of forming a light-emitting element on a pellet.

Fig. 23 is a diagram showing the trajectory of light emitted from a light emitting element.

FIG. 24 is a diagram showing a light source of an image writing device using a microlens array as a directivity unit.

25 is a schematic diagram of a light source and a photosensitive drum of an image writing device using a waveguide as a light condensing unit.

Fig. 26 is a diagram showing the trajectory of light emitted from a light emitting element.

Fig. 27 is a diagram showing the trajectory of light emitted from a light emitting element.

Fig. 28 is a diagram showing a manufacturing process of a waveguide using etching.

29 is a schematic diagram of a light source and a photosensitive drum of an image writing device using a cylindrical lens as a light condensing unit.

Fig. 30 is a schematic diagram of a light source and a photosensitive drum of an image writing device using a microlens as a light condensing unit.

FIG. 31 is an enlarged view showing the vicinity of the light emitting element when light emitted from the light emitting element is emitted to the side of the metal electrode layer.

FIG. 32 is a diagram showing a light source in the case of emitting light emitted from a light emitting element to the side of a metal electrode layer.

Fig. 33 is a schematic diagram of a light source in Embodiment 11 of the present invention.

Fig. 34 is a schematic configuration diagram of a light emitting element.

Fig. 35 is a schematic diagram of a light source in Embodiment 12 of the present invention.

Fig. 36 is an explanatory diagram of a mesa structure.

Fig. 37 is a diagram showing a light source forming process in the thirteenth embodiment.

Detailed ways

(implementation form 1)

The light source 200 of the image writing device of the present invention is used as a light source of a color laser printer (hereinafter referred to as a printer) 100 as shown in FIG. 1 as in the past.

The light source 200 of this embodiment is composed of a transparent substrate 301 elongated in the main scanning direction and a light transmission unit 310 as shown in FIG. 4 . On one side of the above-mentioned transparent substrate 301, a row composed of a plurality of light-emitting elements 8 is formed along the longitudinal direction of the transparent substrate 301 as follows.

First, as shown in FIG. 5(A), a transparent electrode layer 2 such as ITO (indium tin oxide) is coated on the entire surface of a predetermined surface of a transparent substrate 301 . Then, the part of the transparent electrode layer 2 forming the anode transparent electrode element 1 is covered by the light-shielding layer 3, and the transparent electrode layer 2 is subjected to photolithography treatment such as exposure, development, and etching. The unmasked part is removed from the transparent substrate 301 by photolithography as shown in FIG. When the light-shielding layer 3 is used in a plurality of portions at predetermined intervals in the long-side direction of the transparent substrate 301 , columns of transparent electrode elements 1 are formed along the long-side direction.

Next, as shown in FIG. 5(C), an organic EL (electroluminescent material) is fully coated on the transparent substrate 301 forming the transparent electrode element 1 to form an organic EL layer 4, and on the organic EL layer 4 as The common electrode is coated with a metal that becomes the metal electrode layer 5 . The organic EL layer 4 sandwiched between the metal electrode layer 5 and the above-mentioned transparent electrode element 1 becomes a light emitting element 8 .

In order to protect the above-mentioned organic EL layer 4 from physical impact and moisture, sealing treatment is performed. This sealing process is such a process, that is, as shown in FIG. Layer 5 and Resin 6. Light emitting element 8 formed as described above emits light A in a direction perpendicular to transparent substrate 301 , and passes through transparent electrode element 1 and exits from transparent substrate 301 as shown in FIG. 5(D) .

The transparent substrate 301 faces a surface G formed by the longitudinal direction L and the height direction H of the transparent substrate 301 so as to face the photosensitive drum 106 as shown in FIG. 4 .

In addition, a prism 401 elongated in the main scanning direction is disposed on the surface of the transparent substrate 301 opposite to the surface on which the light-emitting elements 8 are formed (hereinafter referred to as light-emitting surface 301 a ) facing the array of light-emitting elements. Therefore, light A emitted from the light emitting element 8 passes through the transparent electrode element 1 and the transparent substrate 301 and enters the prism 401 from the light emitting surface 301 a.

As shown in FIG. 4 , one surface forming the right angle of the rectangular prism here is arranged on the transparent substrate 301 , and the light beam A incident on the surface is redirected by the inclined surface 401 a and exits from the other surface forming the above-mentioned right angle. Thus, the traveling direction of the light beam A is changed to a direction parallel to the transparent substrate 301 (the normal direction of the photosensitive drum 106 ).

A light transmission unit 310 is disposed between the prism 401 and the photosensitive drum 106 , and the light transmission unit 310 makes the light A emitted from the prism 401 form an image on the photosensitive drum 106 to form a latent image. In this embodiment, the light transmission unit 310 is supported by the transparent substrate 301 .

The above-mentioned light transmission unit 310 has a lens array that bundles optical systems such as a plurality of fiber lenses 313 , rod lenses, and microlenses. The optical system used for this lens array may be a lens of an image transmission system, or may be a lens of a light quantity transmission system.

As shown in Figure 6 (A) and Figure 6 (B), the fiber lens array consists of two base frames 311 elongated along the main scanning direction and a light-absorbing layer 312 arranged between the two base frames 311 at predetermined intervals. The axis of each fiber lens 313 is arranged in the enclosed space toward the normal direction of the photosensitive drum 106 . The gap in the space where the fiber lens array is arranged is filled with opaque resin.

The light absorbing layer 312 is used to prevent crosstalk between the fiber lenses 313 . In order to prevent crosstalk, as shown in FIG. In addition, the light-absorbing layer 312 applied between the base frame 311 and the outer periphery of the fiber lens 313 may be used in combination to prevent crosstalk.

The light A whose traveling direction is changed by the prism 401 passes through the light transmission unit 310 and irradiates the photosensitive drum 106 to form a latent image.

As above, by having the prism 401 in the light source 200 as a conversion unit for converting the traveling direction of the light beam A, even if the light emitting surface 301a of the transparent substrate 301 is not made to face the photosensitive drum 106 as in the past, it is possible to make the light emitted from the light emitting element 8 The light A irradiates the photosensitive drum 106 .

FIG. 7(A) shows a cross section of such a writing mechanism 110 in which, when the length h from the light emitting surface 301a to the top 7a of the sealing glass 7 is shorter than the short side s of the transparent substrate 301, the transparent The short side s of the substrate 301 is parallel to the sub-scanning direction, and the light emitting surface 301 a of the transparent substrate 301 is arranged to face the photosensitive drum 106 . In addition, FIG. 7(B) shows a cross section of the writing mechanism 110 in which the surface G formed by the longitudinal direction L and the height direction H of the transparent substrate 301 faces the photosensitive drum 106 as shown in FIG. 4 . The writing mechanism 110 is configured in a similar manner. As shown in FIG. 7(B), by arranging the surface G to face the photosensitive drum 106, the sub-scanning direction of the light source 200 is shortened, so that the writing mechanism 110 having a short sub-scanning direction can be realized.

By shortening the sub-scanning direction of the light source 200, the sub-scanning direction of the writing mechanism 110 shown in FIG.

In addition, in the above description, as shown in FIG. 4, the prism 401 serving as the conversion unit changes the traveling direction of the light beam A by 90 degrees, but the angle for changing the traveling direction can be freely changed by adjusting the angle of the inclined surface 401a of the prism.

Therefore, the layout of the components inside the printer 100 can be designed in such a way that the miniaturization of the entire printer 100 and ease of manufacture of the printer are prioritized over the direction in which the light beam A is emitted.

In addition, the scene where the prism 401 is used as the conversion unit is described above, but if the conversion unit is an object capable of changing the traveling direction of the light A emitted from the light emitting element 8, the material etc. are not limited.

(implementation form 2)

As the conversion means, in addition to the prism 401, a waveguide 402 as shown in FIG. 8 that is transparent and has a higher refractive index than air and the transparent substrate 301 can be considered. As shown in FIG. 8(A) , a reflective material 404 made of a non-transmissive material such as metal is stacked on an opposing surface 407 that faces an exit surface 408 from which light A entering the waveguide 402 exits.

In this waveguide 402 , as shown in FIG. 9 , an upper surface 405 is arranged in contact with the light emitting surface 301 a at each position of the light emitting surface 301 a facing the transparent electrode element 1 .

As described in Embodiment 1, the light emitting element 8 emits the light beam A to the lower side (waveguide 402 side) in FIG. 9 . Therefore, the light A emitted from the light emitting element 8 enters the waveguide 402 from the upper surface 405 of the waveguide 402 through the transparent electrode element 1 and the transparent substrate 301 . In order to reduce the possibility of crosstalk occurring when light A passes through the transparent substrate 301 as much as possible, it is preferable that the transparent substrate 301 is a thin substrate.

As mentioned above, the reflective material 404 is stacked on the opposite surface 407, and the refractive index of the waveguide 402 is higher than that of air and the transparent substrate 301. Therefore, the light A incident on the waveguide 402 from the upper surface 405 undergoes total reflection repeatedly in the waveguide 402, and the light beam A from the exit surface 408 exits.

Therefore, after passing through the waveguide 402, the traveling direction of the light A changes from the downward direction in FIG. 9 to the leftward direction, that is, changes by 90 degrees.

As in Embodiment 1, the light beam A emitted from the emission surface 408 of the waveguide 402 passes through the light transmission unit 310 and irradiates the photosensitive drum 106 to form a latent image.

In addition, above, as shown in FIG. 9, the situation where the traveling direction of the light beam is changed by 90 degrees using the waveguide 402 is described. However, by making the longitudinal direction of the waveguide 402 the direction in which the light beam A is desired to be emitted as shown in FIG. change the direction of travel of ray A.

In addition, when the above waveguide 402 is used as the conversion unit, the cross-sectional area of the light emitted from the emission surface 408 is the same size as the emission surface 408 regardless of the size of the light emission area of the light emitting element 8 . Therefore, by forming the light-emitting element 8 with a large light-emitting area on the transparent substrate 301, the luminous flux density of the light emitted from the emission surface 408 is increased.

Therefore, by using the waveguide 402 as a conversion unit, the sub-scanning direction of the light source 200 is shortened, and at the same time, light with a high beam density can be output. The shape of the waveguide 402 may not be a cuboid as shown in FIG. 8(A), but may be a polygonal prism such as a pentagonal prism or a hexagonal prism as shown in FIGS. 8(B) and 8(C).

(implementation form 3)

In Embodiments 1 and 2, the case where the prism 401 or the waveguide 402 is arranged on the light emitting surface 301a of the transparent substrate 301 is described, but as shown in FIGS. A prism 401 or a waveguide 402 is configured.

That is, a prism 401 is arranged on the sealing glass 7 so that the light A emitted from the light-emitting element 8 is emitted to the opposite side from that in Embodiments 1 and 2, and the light A passes through the sealing glass 7 and enters the prism 401 .

However, when the light source 200 is formed as in the first embodiment, the opaque metal electrode layer 5 is formed on the upper side of the light emitting element 8, so that the light A cannot be emitted to the sealing glass 7 side. In order to improve the luminous efficiency of organic EL, it is necessary to use a substance having a work function lower than that of the transparent electrode element 1 serving as the anode for the cathode, so an opaque metal electrode layer 5 is used for the cathode.

Therefore, the metal electrode layer 5 is formed to have a thickness (approximately 100 Ȧ) to transmit light so that light A is emitted from the side of the sealing glass 7 . In addition, an electrode layer 5 a made of a transparent material is formed on the metal electrode layer 5 so that current flows uniformly through the thin metal electrode layer 5 .

As a result, light A can be emitted upward in FIG. 11 , but it can also be emitted downward. Therefore, a reflector 309 is provided between the transparent substrate 301 and the transparent electrode element 1 in order to prevent downward emission.

In addition, in order to protect the organic EL layer 4 from physical impact and moisture similarly to the first embodiment, the organic EL layer 4 , the metal electrode layer 5 , and the electrode layer 5 a are covered with the resin 6 and the sealing glass 7 .

By making the metal electrode layer 5 thinner in this way, the light A emitted from the light emitting element 8 can exit from the sealing glass 7 and enter the prism 401 arranged on the sealing glass 7 .

The light beam A incident on the prism 401 is reflected by the slope 401 a in the same manner as in the first embodiment, changes its traveling direction, and exits the prism 401 .

When the prism 401 and the light emitting element 8 are arranged on the same surface of the transparent substrate as described above, the light transmission unit is also arranged on the same surface as the surface on which the light emitting element 8 is formed. By arranging the prism 401 and the light transmission unit 310 on the same surface on which the light-emitting element 8 is formed, nothing is formed on the surface opposite to the surface on which the light-emitting element 8 of the transparent substrate 301 is formed, so that the processing of the light source 200 becomes easier. convenient.

Instead of disposing the prism 401 on the sealing glass 7 as described above, the prism 401 or the waveguide 402 may be disposed on the electrode layer 5 a and the resin 6 as shown in FIGS. 12 and 13 . In this case, the prism 401 or the waveguide 402 functions as the sealing glass 7 .

(implementation form 4)

A prism 401 or a waveguide 402 may also be disposed between the transparent substrate 301 and the light emitting element 8 as shown in FIGS. 14 and 15 .

As shown in FIG. 14 , when the prism 401 is disposed on the transparent substrate 301, a triangular prism support stand for supporting the prism 401 by a material having a lower refractive index than the prism 401 or an opaque material is disposed on the transparent substrate 301. 502. The slope 401 a of the prism is provided on the slope side of the support stand 502 , and the prism 401 is arranged on the support stand 502 .

The light emitting element 8 is formed on the prism 401 by the method of forming the light emitting element 8 on the transparent substrate 301 in the first embodiment. In addition, the light transmission unit 310 is arranged on the surface of the transparent substrate 301 on which the prism 401 is arranged.

As shown in FIG. 14, the light A emitted from the light emitting element 8 passes through the transparent electrode element 1, enters the prism 401, is reflected by the inclined surface 401a, and changes the traveling direction. The reflected light A passes through the light transmission unit 310 to form a latent image on the photosensitive drum 106 .

In addition, as shown in FIG. 15 , instead of the prism 401 , a waveguide 402 may be disposed between the transparent substrate 301 and the light emitting element 8 so that the lower surface 403 is on the transparent substrate 301 side. In this case, the reflective material 404 is laminated on the lower surface 403 so that the light A does not exit from the lower surface 403 .

On the waveguide 402, the light emitting element 8 is formed in the same manner as in the case where the prism 401 is arranged. The light beam A emitted from the light emitting element 8 is repeatedly reflected in the waveguide 402 as in the second embodiment, and exits from the emission surface 408 . The emitted light A passes through the light transmission unit 310 to form a latent image on the photosensitive drum 106 .

As shown in FIG. 15 , the light beam A emitted from the light emitting element 8 enters the waveguide 402 without passing through the transparent substrate 301 . For this reason, if the configuration shown in FIG. 15 is adopted in the image writing apparatus, there is an advantage that crosstalk in the transparent substrate 301 that occurs when the configuration shown in FIG. 9 does not occur.

(implementation form 5)

The light source 200 of this embodiment has a transparent substrate 301 elongated in the main scanning direction and a light transmission unit 310 as shown in FIG. 16 . The transparent substrate 301 and the optical transmission unit 310 are respectively supported on the casing of the printer 100, or one of the transparent substrate 301 and the optical transmission unit 310 is supported on the casing, and the transparent substrate 301 and the optical transmission unit are connected by a spacer member not shown in the figure. The transport unit 310 is thus fixed to the printer 100 .

On the transparent substrate 301, as shown in FIG. 17, a plurality of small protrusions 202d having a mesa structure such as a quadrangular pyramid are arranged at predetermined intervals along the main scanning direction, and the transparent substrate 301 and the small protrusions 202d are integrated. For example, when the light source 200 can print an image of 2400 dpi, the interval between the small protrusions 202d is about 10 μm.

The above-mentioned small protrusions 202d can also be formed on the transparent substrate 301 as the substrate by etching as shown below, or by molding synthetic resin or the like by embossing, or integrally molded with the transparent substrate 301 by injection molding.

The shape of the small protrusion 202d also can not be a quadrangular pyramid, as shown in Figure 18, the angle G, H formed by the side 202c of the small protrusion 202d and the transparent substrate 301 becomes an acute angle shape, then it can also be a truncated cone, a triangular pyramid Frustum, pentagonal, and other polygonal truncated pyramids. In addition, the material of the small protrusion 202d is preferably transparent and has the same refractive index as the material of the light emitting element 8 serving as the light source 200 . In this embodiment, the case where an organic EL (electroluminescent material) having a refractive index of about 1.7 is used for the light-emitting element 8 is described. Therefore, in this embodiment, it is preferable that the material used for the small protrusion 202d has a refractive index of about 1.7. .

The light-emitting element 8 shown in FIG. 19(C) is formed on the upper bottom surface 202a of each small protrusion 202d in the following manner.

First, the transparent electrode layer 2 is coated on the entire surface of the transparent substrate 301 on which the small protrusions 202d are arranged as shown in FIG. 19(A). Then, the upper bottom surface 202a of each small protrusion 202d in the transparent electrode layer 2 is covered by the light-shielding film 3, which is the upper part of the central part, and the transparent electrode layer 2 is subjected to photolithography treatment such as exposure, development, and etching. As shown in FIG. 19(B) , the transparent electrode layer 2 is removed in the uncovered portion by photolithography, and the covered portion becomes the transparent electrode element 1 .

Next, as shown in FIG. 19(C), the organic EL layer 4 is coated on the entire surface of the transparent substrate 301 forming the transparent electrode element 1, and the metal electrode layer 5 is coated on the organic EL layer 4 as a common electrode. The portion of the organic EL layer 4 sandwiched between the metal electrode layer 5 and the transparent electrode element 1 becomes a light emitting element 8 .

In order to protect the above-mentioned organic EL layer 4 from physical impact and moisture, as shown in FIG. 19(D), resin 6 is applied to the above-mentioned sealing treatment part 304, and the above-mentioned transparent electrode element 1 is formed by covering with sealing glass 7. , the organic EL layer 4, and the back surface of the transparent substrate 301 of the metal electrode layer 5. The space 9 surrounded by the metal electrode layer 5, the resin 6, and the sealing glass 7 may be vacuum or may be filled with nitrogen gas.

In the above configuration, when a predetermined voltage is applied between the transparent electrode element 1 and the metal electrode layer 5 of the light source 200, the light emitting element 8 emits light. The light rays A, B, and C emitted from the light emitting element 8 pass through the upper bottom surface 202a of the small protrusion 202d and enter the small protrusion 202d as shown in FIG. 18 .

Among the light rays A, B, and C incident on the small protrusion 202d, the light A with a smaller incident angle θ1 relative to the upper bottom surface 202a, that is, the traveling direction is the same as the axial direction of the fiber lens 313, or the approaching light A is not in the small protrusion 202d Reflectively emerges from the lower bottom 202b of the protrusion 202d to the transparent substrate 301 . On the other hand, when the light rays B and C with a large incident angle θ1 enter from the upper bottom surface 202a, they reach the side surface 202c of the small protrusion 202d.

As mentioned above, the refractive index of the small protrusion 202d is 1.7, which is larger than the vacuum or nitrogen forming the space 9. In addition, as shown in FIG. 18, ∠G and ∠H are acute angles. , C increases with respect to the incident angle θ2 of the side surface 202c of the small protrusion 202d. For this reason, light rays such as light rays B and C having a large incident angle θ1 have a high probability of being totally reflected by the side surface 202c. Light rays B and C are given orientation in a direction close to the axial direction of fiber lens 303 by total reflection, and exit from lower bottom portion 202 b to transparent substrate 301 .

Therefore, when a light beam having a large incident angle θ1 passes through the small protrusion 202d, the traveling direction becomes the same as the axial direction of the fiber lens 313 . That is, passing through the small protrusion 202d increases the light rays within the range of the aperture angle of the fiber lens 303 .

As shown in FIG. 16 , the surface (surface) of the transparent substrate 301 opposite to the surface on which the small protrusions 202 d are disposed is disposed at a position facing the photosensitive drum 106 across the light transmission unit 310 . Therefore, the light emitted from the lower bottom portion 202b of the small protrusion 202d as described above proceeds toward the above-mentioned light transmission unit 310 through the transparent substrate 301 .

The traveling direction of the plurality of light rays reaching the light transmission unit 310 is the same direction as the axial direction of each fiber lens 303 constituting the light transmission unit 310 as described above, so even if the aperture angle of the fiber lens 303 is small, each light beam It is also guided into the light transfer unit 310 through which the photosensitive drum 106 is irradiated.

When the light-emitting element 8 is formed on the transparent substrate 301 having the small protrusions 202d, compared with the case where the light-emitting element 8 is formed on the transparent substrate 301 without the small protrusions 202d, the intensity of light between the light-emitting element 8 and the photosensitive drum 106 is lower. The transfer efficiency is about 4 times better.

In addition, by using the directional means such as the above-mentioned small protrusions 202d, it is not necessary to increase the aperture angle of the fiber lens 303 in order to improve the light transmission efficiency, so the depth of focus of the light transmission means 310 is still large. Therefore, a clear latent image is easily formed on the photosensitive drum 106 .

However, the above-mentioned etching treatment is, for example, dry etching for forming the above-mentioned mesa structure.

When the small protrusions 202d are formed by dry etching, first, as shown in FIG. 20(A), a substance to be the orientation imparting layer 801 is formed on the entire surface of the transparent substrate 301 by coating or vapor deposition. The material of the orientation-imparting layer 801 is the same as that of the small protrusions 202d. Then, the above-mentioned transparent electrode layer 2 is formed on the above-mentioned orientation imparting layer 801 by coating or vapor deposition. The portion of the transparent electrode element 1 where the transparent electrode layer 2 is formed is covered with the light-shielding film 3 .

With respect to the transparent substrate 301 on which the transparent electrode layer 2 is formed in this way, the reaction catalyst is introduced into the side surface forming portion (section 808 ) through the mask 809 for controlling the etching depth as shown in FIG. 20(B) . The depth of corrosion is affected by the amount of reaction catalyst introduced. For this purpose, the mask 809 uses, for example, a metal mesh whose opening size is adjusted according to the depth of etching. That is, the portion corresponding to the deeply etched portion (central portion of the section 808) has a larger opening in order to increase the amount of the reaction catalyst entering, and the portion corresponding to the shallowly etched portion (the end portion of the section 808) is designed to reduce the amount of reaction catalyst entering. Ingress volume, reduce opening.

When etching, the portion of the transparent electrode layer 2 and the orientation-imparting layer 801 into which the reaction catalyst is put is removed, and together with the transparent electrode element 1, small protrusions 202d in the shape of a truncated polygon as shown in FIG. 20(B) are formed. This small protrusion 202d becomes an orientation unit.

As described above, by simultaneously etching the orientation-imparting layer 801 and the transparent electrode layer 2, the number of steps for forming a light source can be reduced. In addition, when the transparent electrode element 1 and the orientation imparting means are formed separately, positioning of the mask is required when a mask is used, but this positioning is rendered unnecessary by simultaneous etching.

(implementation form 6)

As the above-mentioned directional means, it is conceivable to use a small ball chip 220 as shown in FIG. Form protrusions. When the small ball sheet 220 is used as the orientation unit, the above-mentioned light-emitting element 8 is formed on the surface of the small ball sheet 220 opposite to the surface on which the protrusions are formed as follows.

First, as shown in FIG. 22(A), the transparent electrode layer 2 is coated on the entire surface of the pellet sheet 220 opposite to the surface on which the protrusions are provided. Then, in the same manner as in the fifth embodiment, the portion of the above-mentioned transparent electrode layer 2 where the transparent electrode element 1 is to be formed is covered with the light-shielding film 3 .

Then, a photolithography process is performed to form a transparent electrode element 1 at the masked portion as shown in FIG. 22(B). Thereafter, the organic EL layer 4 and the metal electrode layer 5 are formed in the same manner as in the fifth embodiment. In this way, the part of the organic EL layer 4 between the transparent electrode element 1 and the metal electrode layer 5 becomes a light emitting element 8 . Similar to Embodiment 5, in order to protect the organic EL layer 4 from physical impact and moisture, resin 6 is applied to the sealing treatment part 304 as shown in FIG. 22(C), and the metal electrodes are covered with sealing glass 7. Layer 5 and Resin 6.

In the above configuration, the light A emitted from the light emitting element 8 enters the pellet 220 through the transparent electrode element 1 as shown in FIG. 23 . Since the protrusion is provided on the surface of the small ball chip 220 on the side of the light transmission unit 310 as described above, the probability that the angle of the light A relative to the protrusion when exiting the small ball chip 220 becomes smaller than that when it exits from a portion without the protrusion. high. Therefore, by providing the protrusions, the light rays that are totally reflected when exiting the small bead 220 are reduced, and the amount of light that is exiting the light transmission unit 310 side of the small bead 220 is increased.

In addition, when emitted from the small ball sheet 220, the difference in refractive index between the small ball sheet 220 and the outside of the small ball sheet imparts orientation to the light beam, and the traveling direction of the light beam whose traveling direction is inclined with respect to the axial direction of the fiber lens 303 becomes the same as that of the light beam. The axial direction of the fiber lens 303 is the same direction.

By using the small ball sheet 220 as the directivity means in this way, a large amount of light is emitted from the small ball sheet 220 and directionality is imparted at the same time. In the case where the light emitting element 8 is formed on the small ball chip 220, the transmission efficiency of light between the light emitting element 8 and the photosensitive drum 106 is about twice as high as that in the case where the light emitting element 8 is formed on the transparent substrate 300 without protrusions. .

If the protrusion provided on the small ball sheet 220 is a shape that allows more light to exit from the small ball sheet 220 and imparts directionality to the light, it may also be conical, truncated cone, dome, triangular pyramid, quadrangular pyramid, etc. .

In addition, the size of the protrusion of the small ball chip 220 is not limited, but it is preferably smaller than the light emitting element 8 . For example, when the size of the light emitting element 8 and the protrusion are the same, a positioning process of the light emitting element 8 and the protrusion is required when assembling the light source 200 so that light emitted from the light emitting element 8 is emitted from one protrusion. However, the smaller the protrusions are, the more the number of protrusions through which the light emitted by each light emitting element 8 passes is substantially the same number even if the positioning of the light emitting element 8 and the protrusions is not performed. Therefore, the deviation between the transmittance of light emitted from each light emitting element 8 and the imparted directivity becomes small.

In addition, since the small ball sheet 220 has the functions of the orientation unit and the transparent substrate 301 as described above, the step of arranging the small protrusions 202d as in the first embodiment can be omitted during assembly of the light source 200 using the small ball sheet 220 .

(implementation form 7)

In Embodiment 7, the case where the small ball chip 220 provided with protrusions on the transparent substrate 301 is used as the orientation unit is described, but it can also be arranged between the transparent substrate 301 and the light transmission unit 310 as shown in FIG. 24 In the microlens array 230 shown, protrusions are provided instead of the transparent substrate 301 .

The process of forming the light emitting element 8 formed on the transparent substrate 301 in this case is the same as that of the sixth embodiment except that the light emitting element 8 is formed on the transparent substrate 301 without protrusions.

The microlens array 230 serving as an orientation unit is fabricated by injection molding or irradiating ultraviolet rays to photosensitive glass.

The microlens array 230 is supported on the transparent substrate 301 via the spacer S as shown in FIG. 24 , for example.

The light emitted from the light-emitting element 8 enters the microlens array 230 through the transparent substrate 301 . In addition, when emitting from the microlens array 230, the traveling direction of the light is changed according to the same principle as when emitting from the above-mentioned small ball sheet 220, so that the traveling direction of many light rays is the same as the axial direction of the fiber lens 303.

The size of the microlens is not limited, but it is preferably smaller than the above-mentioned transparent electrode element 1 in the same size as the protrusion of the pellet 220 .

(implementation form 8)

As described above, changing the traveling direction of light to improve the transmission efficiency of light between the light-emitting element 8 and the photosensitive drum 106, and to improve the structure of the illuminance on the photosensitive drum will be explained below by increasing the luminous intensity of each light-emitting element 8 to improve the light intensity on the photosensitive drum. The composition of the illuminance.

In order to increase the light emission intensity of each light emitting element 8, the light emitting area of each light emitting element 8 is enlarged in this embodiment. As described above, in order to print a high-resolution image, the light emitting elements 8 must be arranged at narrow intervals along the main scanning direction, so there is a limit to the length of the light emitting elements 8 in the main scanning direction.

However, since there is no such limitation regarding the sub-scanning direction, the light-emitting element 8 can be enlarged by extending the sub-scanning direction of the light-emitting element 8 . However, the cross section of light emitted from the light emitting element 8 elongated in the sub-scanning direction is elongated in the sub-scanning direction. For this reason, the pixels of the latent image formed on the photosensitive drum 106 are elongated in the sub-scanning direction. In order to prevent this, before the light emitted from the light emitting element 8 reaches the photosensitive drum 106 , it is necessary to make the length of the cross section of the light in the sub-scanning direction the same as that in the main scanning direction.

Therefore, in the present embodiment, the waveguide 402 is used as a light condensing means for condensing the light emitted from the light emitting element 8 in the sub-scanning direction.

As described in Embodiment 2, the reflective material 404 that does not transmit light is laminated on the opposing surface 407 of the waveguide 402 that faces the output surface 408 .

The waveguides 402 are arranged on the transparent substrate 301 at predetermined intervals along the main scanning direction. The predetermined interval is the same interval as the pixels of the printed image. In order to prevent the crosstalk of light incident on each waveguide 402 , the space between the waveguides 402 may be formed as an air layer, or may be filled with a substance having a lower refractive index than the waveguides 402 .

On each waveguide 402, the light emitting element 8 is formed in the same process as the process of forming the light emitting element 8 on the small protrusion 202d in the first embodiment. Although not shown in FIG. 25 , here, in order to protect the organic EL layer 4 from physical impact and moisture, resin 6 is applied to the above-mentioned sealing treatment part 304 , and the metal electrode layer 5 and the resin 6 are covered with sealing glass 7 . .

The light beam A emitted from the light emitting element 8 enters the waveguide 402 through the transparent electrode element 1 as shown in the cross-sectional view of FIG. 25 ( FIG. 26 ). The refractive index of the waveguide 402 is higher than that of the transparent substrate 301, vacuum, and air. The opposite surface 407 of the waveguide 402 is laminated with a reflective material 404. Therefore, the light A incident on the waveguide 402 is repeatedly reflected in the waveguide 402 and exits from the exit surface 408. The light beam A emitted from the light emitting element 8 exits from the exit surface 408 , so the cross section of the light emitted from the light emitting element 8 has the same size as that of the exit surface 408 .

Therefore, if the section of the emission surface 408 is set to have the same area as the area of the pixel of the latent image formed on the photosensitive drum 106, regardless of the shape of the light emission surface of the light emitting element 8, the light emitted from the emission surface 408 The section is also a necessary area.

Therefore, the larger the light emitting area of the light emitting element 8 is, the higher the beam density of the light emitted from the emitting surface 408 is. As described above, since the length of the light-emitting element 8 in the sub-scanning direction is not limited, by forming the light-emitting element 8 elongated in the sub-scanning direction on the waveguide 402 , light with a high beam density can be obtained from the output surface 408 . In addition, when the light is condensed in the sub-scanning direction, light with a high light velocity density and the same cross-sectional length in the main-scanning direction and the sub-scanning direction can be obtained from the output surface 408 .

In the light source 200 having the waveguide 402 , since the light is emitted from the emission surface 408 , the light transmission unit 310 is provided in front of the emission surface 408 as shown in FIG. 25 . The light emitted from the emission surface 408 passes through the light transmission unit 310 and irradiates the photosensitive drum 106 in the same manner as in Embodiments 5 to 7 described above.

Therefore, even in the light source 200 in which the light emitting elements 8 are formed at short intervals along the main scanning direction, light with a high beam density can be obtained by using the condensing unit. Therefore, a high-resolution latent image can be formed using the light source of the light-collecting unit.

In addition, by using the waveguide 402 as a light-condensing unit, it is not necessary to apply a large electric field to the transparent electrode element 1 and the metal electrode layer 5 in order to obtain light with a high beam density as in the past, and the light-emitting life of the light-emitting element 8 will not be shortened. .

In addition, the shape of the waveguide 402 is not limited to the cuboid shown in FIG. 25 . For example, as shown in FIG. 27 , polygonal prisms such as pentagonal prisms and hexagonal prisms, and truncated cone-shaped lower and upper bases may be polygonal.

Furthermore, although the waveguide 402 can also be manufactured by injection molding, it can also be manufactured by etching as follows. For example, as shown in FIG. 28(A), a substance 242 to be a waveguide 402 is coated on a transparent substrate 301, and then a transparent electrode layer 2 is coated thereon. Then, the transparent electrode layer 2 and the substance 242 are etched by covering the part of the transparent electrode layer 2 where the transparent electrode element 1 is formed by the light-shielding layer 3 . In this way, the transparent electrode element 1 and the waveguide 420 are formed as shown in FIG. 28(B).

In addition, as described above, the waveguide 402 can make the cross-section of the light emitted from the light-emitting element 8 the same area as the pixel of the latent image. Therefore, if the waveguide 402 is arranged so that the above-mentioned emission surface 408 is close to the photosensitive drum 106, it is not necessary to use The light source 200 is provided with a light transfer unit 310 .

In addition, by making the output surface 408 a convex curved surface like a convex lens, the light passing through the output surface 408 can be formed into an image on the photosensitive drum 106 . Of course, even when the emission surface 408 is a convex curved surface, it is not necessary to provide the light transmission unit 310 in the light source 200 .

(implementation form 9)

As the light collecting means, a convex cylindrical lens 250 may be used instead of the waveguide 402 . In this case, the cylindrical lens 250 is provided with a curved surface toward the photosensitive drum 106 side between the light transmission unit 310 and the photosensitive drum 106 as shown in FIG. 29 . The cylindrical lens 250 is supported by the light transmission unit 310 or by the housing of the printer 100 through a not-shown spacer member.

The light emitting element 8 is formed on the transparent substrate 301 by the same process as in the sixth embodiment, but the light emitting element 8 in this embodiment is different from the light emitting element 8 in the sixth embodiment in that it is longer in the sub-scanning direction than in the main scanning direction. The light-emitting element 8 is long in the sub-scanning direction because there is a limitation in length in the main-scanning direction as described in the eighth embodiment. Although not shown in FIG. 29 , even in this embodiment, the metal electrode layer 5 is covered with a resin 6 and a sealing glass 7 in order to protect the organic EL layer 4 .

As shown in FIG. 29 , the light emitted from the light emitting element 8 enters the cylindrical lens 250 through the transparent substrate 301 and the light transmission unit 310 . The light incident on the cylindrical lens 250 shrinks in the sub-scanning direction when emitted from the convexly curved surface of the cylindrical lens, and the lengths of the light cross section on the photosensitive drum 106 in the main-scanning direction and the sub-scanning direction become the same.

When the cylindrical lens 250 is used as a condensing unit, the distance between the cylindrical lens 250 and the photosensitive drum 106 can be adjusted freely by adjusting the radius of curvature and the refractive index of the cylindrical lens 250 and the photosensitive drum 106. The length of the section in the sub-scanning direction.

Therefore, as in Embodiment 8, the length of the light-emitting element 8 in the sub-scanning direction is increased as much as possible, and the radius of curvature of the cylindrical lens 250, the refractive index, and the distance between the cylindrical lens 250 and the photosensitive drum 106 are adjusted, so that The lengths of the cross-section in the main scanning direction and the sub-scanning direction are equal, and light with a high beam density can be obtained. However, when the light is focused only in the sub-scanning direction, only the focal length of the light in the sub-scanning direction is shortened, and there is a difference in focal length between the main-scanning direction and the sub-scanning direction. Therefore, if the sub-scanning direction of the light emitting element 8 is too long relative to the main-scanning direction, the difference in focal length from the main-scanning direction increases, so that a sharp latent image cannot be obtained on the photosensitive drum.

In Embodiment 9, the case where the convex cylindrical lens 250 is used as the light collecting means is described, but the microlens array 260 may be used as the light collecting means instead of the cylindrical lens 250 .

The microlens array 260 serving as light-collecting means is arranged in a line along the main scanning direction as shown in FIG. 30 , and the shape of each microlens is an ellipse whose major axis is parallel to the sub-scanning direction. The purpose of forming an ellipse in this way is to shrink the light toward the sub-scanning direction.

In Fig. 29 and Fig. 30, the cylindrical lens 250 or the microlens array 260 is arranged between the light transmission unit 310 and the photosensitive drum 106, but the cylindrical lens 250 or the microlens array 260 may also be arranged between the transparent substrate 301 and the photosensitive drum 106. Between the transfer unit 310.

When the light transmission unit 310 is formed of lenses of an image transmission system, the light transmission unit 310 may be directly disposed on the cylindrical lens 250 or the microlens array 260 .

(implementation form 10)

In the fifth to ninth embodiments, the respective layers are formed in the order of the transparent electrode element 1, the organic EL layer 4, and the metal electrode layer 5. Therefore, the light emitted from the light emitting element 8 is emitted to the transparent substrate 301 side as shown in FIG. 16 .

However, the light source 200 may emit light to the upper side in FIG. 16 which is the opposite side to Embodiments 5 to 9. As shown in FIG.

Since the opaque metal electrode layer 5 is formed on the upper side of the light-emitting element 8 as described in Embodiments 5 to 9 above, light cannot be emitted upward. As described in Embodiment 4, in order to improve the luminous efficiency of organic EL, it is necessary to use a substance having a lower work function than the transparent electrode element 1 serving as the anode for the cathode, so an opaque metal electrode layer 5 is used for the cathode.

Therefore, in order to emit light to the upper side, as shown in FIG. 31 , the metal electrode layer 5 is formed to have a thickness (approximately 100 Ȧ) that allows light to pass through. This enables the light to exit upwards. However, since it can emit downward, a reflective material 404 is provided between the transparent substrate 301 and the transparent electrode element 1 in order to prevent downward emission.

In addition, like the fourth embodiment, the electrode layer 5a is formed on the metal electrode layer 5 so that the current flows uniformly to the thin metal electrode layer 5 . Also in this embodiment, the organic EL layer 4 , the metal electrode layer 5 , and the electrode layer 5 a are covered with the resin 6 and the sealing glass 7 in order to protect the organic EL layer 4 .

In this way, when the light is emitted upward, as shown in FIG. 32(A) and FIG. 32(B), the above-mentioned small protrusion 202d or the waveguide 402 is formed on the above-mentioned electrode layer 5a, and the light-emitting element 8 is sealed by the sealing glass 7. and small protrusions 202d or waveguides 402.

(implementation form 11)

The light source 200 of this embodiment shown in FIG. 33 is composed of a light transmission unit 310 and a light emitting element 8 . The light transfer unit 310 is required to accurately form a latent image on the photosensitive drum 106 as described above. The above-mentioned light emitting element 8 is constituted by a planar light emitting body, and an organic electroluminescence material (hereinafter referred to as organic EL) is used as an example of the planar light emitting body.

In addition, one light emitting element 8 is provided on the light transmission unit 310 corresponding to one single lens 313 (hereinafter referred to as single lens 313) constituting the fiber lens array shown in FIG. The light from the corresponding single lens 313 is irradiated onto the photosensitive drum 106 to form a latent image.

The above-mentioned light emitting element 8 is directly formed on the light transmission unit 310, and its manufacturing method will be described below.

First, as shown in FIG. 34 , a transparent electrode layer 2 such as an ITO electrode, which is a material of the transparent electrode element 1 , is formed on the entire opening surface (section of the single lens 313 ) of the light transmission unit 310 by deposition, coating, or the like. Through this formation, the transparent electrode layer 2 is optically in close contact with the light transmission unit 310 .

Next, cover only the parts that need to emit light on the above-mentioned light transmission unit 310 by the light-shielding film 3, that is, the upper part of each of the above-mentioned single lenses 313 in this embodiment, and perform photolithography treatment such as exposure and development on the above-mentioned opening surface and etching. The processing is patterning processing. Through this patterning process, the transparent electrode layer 2 in the part not covered is removed, and the covered part becomes the transparent electrode element 1 .

Then, an organic EL layer 4 is formed by coating the entire opening surface of the transparent electrode element 1 with organic EL, and a metal electrode layer 5 is formed on the organic EL layer 4 as a common electrode. The organic EL layer 4 sandwiched between the transparent electrode element 1 and the metal electrode layer 5 becomes a light emitting element.

As the sealing treatment of the above-mentioned light-emitting element 8, the resin 6 is applied to the sealing treatment part 304 around the single lens 313, and finally the metal electrode layer 5 on the upper part of the above-mentioned opening surface is covered and coated with a substantially U-shaped sealing glass 7. The above-mentioned resin 6 in the common peripheral portion. The light source 200 is thus completed.

As above, the light source 20 in which the light transmission unit 310 and the light emitting element 8 are optically integrated is formed. The light source 200 thus formed causes the organic EL layer 4 sandwiched between the transparent electrode element 1 and the metal electrode layer 5 to emit light by applying an electric field to the transparent electrode element 1 and the metal electrode layer 5 .

As described above, by directly forming light-emitting element 8 using organic EL on light-transmitting unit 310 , light emitted from light-emitting element 8 is directly transmitted to light-transmitting unit 310 without passing through a layer with low refractive index and no orientation. Therefore, the light is substantially not totally reflected, and can reach the photosensitive drum 106 while maintaining a sufficient luminous intensity. Therefore, a high-resolution latent image can be formed without shortening the light-emitting life of the light-emitting element 8 and without increasing the aperture angle and reducing the depth of focus. In other words, since there is no total reflection of light in the light source of this embodiment, when forming a latent image with a predetermined resolution, the power used by the light source of this embodiment can be compared to that of a layer with a low refractive index and no orientation. The light source of this configuration uses less power when forming a latent image with a predetermined resolution.

(implementation form 12)

Next, a configuration in which the diameters of the individual lenses 313 constituting the light transmission unit 310 of the light source 200 shown in FIG. 35 are made smaller than the vertical and horizontal dimensions of the above-mentioned light emitting element 8 will be described.

In the light source 200 shown in FIG. 35 , the light-emitting element 8 is formed on the light transmission unit 310 , but the single lens 313 uses a lens whose diameter is smaller than the vertical and horizontal lengths of the light-emitting element 8 . That is, one light emitting element 8 corresponds to a plurality of single-piece lenses 313 .

The single lens 313 is accommodated in a space surrounded by the light absorbing layer 312 and the base frame 313 as shown in FIG. The absorbing layer 312 is housed in the above-mentioned space.

The light emitting element 8 described above may also be provided on such a light transmission unit 310 . The method of directly forming the light-emitting element 8 on the light transmission unit 310 is preferably the same as the method described in the above-mentioned embodiment. In this configuration, since the diameter of the fiber lens 313 is smaller than that of the light emitting element 8, the light emitting element 8 can be formed without considering the delicate positional relationship between the light emitting element 8 and the single lens 313. Manufacturing of the light source 200 of the light transmission unit 310 becomes easy.

(implementation form 13)

Next, the light source 200 is described below. The light source 200 is provided with a directional unit that unifies the traveling direction of each light beam emitted from the light emitting element 8 to a predetermined direction between the light emitting element 8 and the light transmission unit 310, and integrally forms the above-mentioned light source 200. The transmission unit 310 , the above-mentioned directional unit, and the above-mentioned light emitting element 8 .

The above-mentioned directional unit plays a role of correcting the traveling direction of the light and guiding more light into the above-mentioned light transmission unit 310 . In the thirteenth embodiment, a case where the above-mentioned directional unit has a mesa structure (mesa sheet) will be described. The above-mentioned mesa structure is a structure that corrects the incident light to a predetermined direction by reflecting the incident light, and has a polygonal truncated pyramid structure in which light emitting elements 8 are arranged on the upper bottom as shown in FIG. 36(B). That is, in the case of a directivity unit 701 without a mesa structure as shown in FIG. , Therefore, the light incident on the lower surface 706 decreases, and as a result, the transmission efficiency decreases. However, in the directional unit 701 with mesa structure shown in FIG. 36(B), the reflectivity of the light emitted from the light-emitting element 8 at a predetermined exit angle θ702 on the side surface 701a of the directional unit is improved, and the light rays reaching the bottom 706 The amount of reduction becomes small, and as a result, the transfer efficiency improves. The aforementioned FIGS. 36(A) and (B) are for comparing the same light emitted from the aforementioned light-emitting element 8 .

Next, a method of manufacturing a light source including the above-described directional unit 701 having a mesa structure optically and integrally provided will be described.

First, as shown in FIG. 37(A), an orientation-imparting layer 801 is formed on the light transmission unit 310 described in Embodiments 11 and 12 above. This formation is performed by applying, vapor-depositing, or the like the substance to be the above-mentioned orientation-imparting layer. Then, the transparent electrode layer 2 is similarly coated and vapor-deposited on the above-mentioned orientation-imparting layer 801 . The above-mentioned orientation-imparting layer 801 is, for example, a material containing acrylic or polyaryl resin as a component.

After the orientation imparting layer 801 and the transparent electrode layer 2 are formed on the light transmission unit 3101, the etching for forming the small protrusions described in Embodiment 5 is performed on the orientation imparting layer 801 and the transparent electrode layer 2 formed on the light transmission unit 301. . In this way, as shown in FIG. 37(B), the orientation-imparting layer 801 having a mesa structure and the transparent electrode element 1 are simultaneously formed.

Then, the organic EL to be the light-emitting element 8 and the metal to be the metal electrode layer 5 are vapor-deposited on the transparent electrode element 1 shown in FIG. 37(B) above.

Here, the above-mentioned directional unit 701 has a thickness compared with the above-mentioned transparent electrode element 1 , light emitting element 8 , and metal electrode layer 5 . In addition, a section 808 without an upper bottom of the directivity unit 701 is provided between the respective transparent electrode elements 1 . For this reason, after performing the etching for obtaining the mesa structure, when the organic EL or metal is vapor-deposited on the entire surface of the directional unit 701 forming the mesa structure and the light transmission unit 310 of the transparent electrode element 1, it is vapor-deposited on the section 808. The organic EL and metal flow down to the lower end portion of the directivity cell 701 along the side face 701 a of the directivity cell 701 . For this reason, the organic EL and metal vapor-deposited on each transparent electrode element 1 are cut off from the organic EL and metal vapor-deposited on other transparent electrode elements 1 .

Therefore, even if organic EL and metal are not vapor-deposited on each transparent electrode element 1, for example, organic EL and metal are vapor-deposited on the entire surface of the light transmission unit 301, the light-emitting element 8 and the metal electrode layer can be formed on each directional unit 701. 5. When the organic EL and metal are vapor-deposited on the entire surface of the light transmission unit 301 to form the light-emitting element 8 and the metal electrode layer 5 , it is not necessary to perform masking treatment when vapor-depositing the light-emitting element 8 and the metal electrode layer 5 . However, when the metal electrode layer 5 and the transparent electrode element 1 are disconnected, the light emitting element 8 does not emit light, so the metal electrode layer 5 may be formed by evaporating metal only on the upper part of the light emitting element 8 .

As described above, by integrally forming the light transmission unit, the orientation unit, and the light emitting layer, there is no layer having a low refractive index and no orientation between the respective layers. In this way, the light emitted from the light emitting element is directly transmitted to the light transmission unit without passing through the non-directional layer. Therefore, as described above, the light can reach the photosensitive drum with substantially no total reflection and maintain sufficient luminous intensity. In addition, since the directional means unifies (corrects) the light emitted from the light emitting element to a predetermined angle, substantially all the light emitted from the light emitting element can reach the light transmitting means. In addition, since there is no non-directional layer when reaching the light transmission unit, the light reaches the photosensitive drum with a stronger luminous intensity than in the eleventh and twelfth embodiments.

When the directional unit having a mesa structure is provided, the transmission efficiency of light between the organic EL layer and the photosensitive drum is four times that of the case where the directional unit is not provided.

Of course, by using the above-described directivity unit, there is no need to increase the aperture angle in order to improve the light transmission efficiency, and as a result, the depth of focus of the light transmission unit can be kept large. Therefore, the light source can of course correctly form a latent image on the photosensitive drum.

The above has described the occasion where the light source 200 of the image writing device of the present invention is used in a color laser printer 100 using a tandem method, but the light source 200 of the image writing device of the present invention can also be used as a color laser printer that does not use a tandem method. Light source for laser printers, laser printers capable of monochrome printing only.

Possibility of industrial use

In the present invention, by changing the traveling direction of the light emitted from the light source of the image writing device, the direction in which the light is emitted may not be considered in the direction in which the light source is arranged. Therefore, the image writing device of the present invention is useful as a light source capable of downsizing the printer by arranging the light source in the direction in which the sub-scanning direction of the printer becomes shorter.

In addition, the light source of the image writing device has a directivity unit that gives directionality to the light emitted from the light emitting element, so even if the aperture angle of the light transmission unit is not increased, many rays of light can be transmitted to the photosensitive drum through the light transmission unit. . Therefore, in the state where the depth of focus of the light transmission unit is kept large, the transmission efficiency of light between the light emitting element and the photosensitive drum is improved, so as the illuminance on the photosensitive drum is improved and a clear latent image is formed on the photosensitive drum The light source is useful as the light source of the image writing device of the present invention.

In addition, light emitted from a light-emitting element having a large light-emitting area is condensed by the condensing means, so that light with a high luminous flux density can be obtained by having the condensing means. By having the condensing unit and the light-emitting element elongated in the sub-scanning direction in the light source, and by condensing the light emitted from the light-emitting element in the sub-scanning direction, it is possible to obtain light with a high beam density at short intervals in the main-scanning direction. Light. Therefore, the light source of the image writing device of the present invention is useful as a light source for forming a high-resolution latent image on the photosensitive drum.

In addition, since the light transmission unit, the orientation unit, and the light emitting layer are integrally formed, there is no layer having a low refractive index and no orientation between the respective layers. In this way, the light emitted from the light emitting element is directly transmitted to the light transmission unit without passing through the non-directional layer. Therefore, the light source of the image writing device of the present invention is useful as a light source that reaches the photosensitive drum with substantially no total reflection of light and maintains sufficient luminous intensity.

Claims (14)

1. A light source of an image writing device, used to conduct light emitted from a light-emitting element to a photosensitive drum, which has A waveguide for each element to transform the direction of travel of the light emitted from the light-emitting element; The light transmission unit is used to transmit the light to the photosensitive drum, wherein the traveling direction of the light is changed by the waveguide. 2. The light source of an image writing device according to claim 1, wherein the light-emitting element is formed on one surface of the substrate to emit light upward relative to the one surface, The waveguide is formed on the light emitting element. 3. The light source of the image writing device according to claim 1, wherein the above-mentioned light-emitting element is formed on one surface of the substrate so as to emit light in a downward direction from the surface to the opposite surface, The above-mentioned waveguide is formed on the opposite face so as to correspond to the above-mentioned light emitting unit. 4. The light source of an image writing device according to claim 1, wherein the waveguide is formed on one side of the substrate, The light emitting element is formed on one surface of the waveguide. 5. The light source of an image writing device according to any one of claims 1-4, wherein the waveguide is a guide for guiding the light in a predetermined direction. 6. The light source of the image writing device according to claim 5, wherein the predetermined direction is a direction parallel to the substrate. 7. The light source of the image writing device according to claim 1, wherein the waveguide converts the traveling direction of the light beam to the normal direction of the photosensitive drum. 8. The light source of an image writing device according to claim 1, wherein a plurality of photosensitive drums are arranged in series in the image writing device. 9. The light source of the image writing device according to claim 1, wherein the light emitting element is made of an organic electroluminescent material. 10. The light source of the image writing device according to claim 1 or 6, wherein the size of the light-emitting element in the sub-scanning direction is larger than the size of the pixels of the latent image in the sub-scanning direction. 11. The light source of the image writing device according to claim 1 or 10, further comprising a light transmission unit configured to make the cross section of the light formed on the photosensitive drum the same as the area of the pixel of the above-mentioned latent image . 12. The light source of the image writing device according to claim 1 or 10, wherein the section of the waveguide has the same area as the cross-sectional area of the pixel of the latent image on the photosensitive drum, and the light emitted from each waveguide Travel directly to the drum. 13. The light source of the image writing device according to claim 1 or 10, wherein the light emitting element is integrally formed with the substrate. 14. The light source of the image writing device according to claim 1 or 10, wherein the light collecting unit reflects the light in the waveguide according to the difference between the refractive index inside the waveguide and the refractive index outside the waveguide. Spotlight.

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