JP4107363B2 - Optical print head and image forming apparatus using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an imaging element array used in a solid-state scanning writing digital writing optical system, and is applicable to a digital copying machine, a printer, a digital facsimile, and the like.
[0002]
[Prior art]
In recent years, with the miniaturization of digital output devices such as digital copying machines, printers, and digital facsimiles, there has been a demand for miniaturization of digital writing devices. Currently, the digital writing method can be roughly classified into two types. One is an optical scanning method in which a light beam emitted from a light source such as a semiconductor laser is optically scanned by a deflector and a light spot is formed by a scanning imaging lens, and the other is a light emitting element such as an LED array. This is a solid-state scanning method in which light beams emitted from the array are formed as light spots by an imaging element array.
[0003]
In the optical scanning method, the optical path length is increased because light is scanned by an optical deflector, whereas in the solid scanning method, the optical path length can be very short, so that the entire apparatus is small. There is also an advantage that a mechanical driving component such as a deflector is not necessary.
[0004]
As a conventional solid scanning digital writing apparatus, for example, there is one described in Japanese Patent Laid-Open No. 10-153751. As shown in FIG. 12A, an imaging element array 90 used in this digital writing apparatus includes an incident surface 90a located on the incident side, which is the light emitting element array side, and a scanned surface of the image carrier. A plurality of imaging elements in which an exit surface 90b positioned on the exit side, which is the side, and two pairs of total reflection surfaces 90c that are substantially perpendicular to each other are integrally formed are arranged. When the imaging element array 90 is viewed from the end surface side in the array direction, the total reflection surface 90c is inclined 45 degrees with respect to the incident optical axis.
[0005]
The light emitted from one point on the light emitting element surface enters the incident surface 90a of the imaging element array 90, is sequentially reflected by the pair of total reflection surfaces 90c, is emitted from the emission surface 90b, and is scanned on the image carrier. To. The incident optical axis and the outgoing optical axis are substantially perpendicular to each other. Due to the imaging action of the incident surface 90a and the exit surface 90b, an image at one point on the light emitting element surface is connected to a corresponding point on the scanned surface on the image carrier.
[0006]
As shown in FIG. 12B, the imaging element array 90 is formed with a plurality of openings 91a in order to optimize the light amount and prevent crosstalk light between adjacent imaging elements. An aperture member 91 is disposed. The aperture member 91 has a plate shape with an L-shaped cross section, and as shown in FIG. 12C, the aperture member 91 has openings so as to correspond to the entrance surface 90a and the exit surface 90b of each imaging element. A plurality of portions 91a are formed on the two plates at regular intervals along the arrangement direction of the imaging elements.
[0007]
[Problems to be solved by the invention]
The thick plate-shaped aperture member 91 having an L-shaped cross section as described above shields most of the light flux emitted from the light emitting element array, and thus reduces the transmission efficiency of the imaging element. . In particular, when the thickness becomes thicker than the arrangement pitch of the imaging element array 90 or the diameter of the opening 91a of the aperture member 91 becomes smaller with respect to the arrangement pitch, the transmission efficiency is significantly reduced.
[0008]
Further, in order to manufacture the aperture member 91 as described above at low cost, molding by resin is desired. However, in the case of molding by resin, there is a limited range in size and thickness that can be manufactured at low cost. In other words, it is difficult to reduce the thickness of the imaging element to such an extent that the transmission efficiency of the imaging element is not lowered or to increase the diameter of the opening 91a.
[0009]
On the other hand, in recent years, the resolution of writing devices is rapidly increasing, and high resolution such as 600 dpi and 1200 dpi is required. Therefore, high imaging performance is also required for the imaging element.
[0010]
The present invention has been made in order to solve the above-described problems of the prior art, and an optical print head capable of improving transmission efficiency and image forming performance, and an image forming apparatus using the same. The purpose is to provide.
[0011]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a light emitting element array in which a plurality of light emitting elements are arranged, and a plurality of image forming elements for imaging light beams from the light emitting elements as light spots on an image carrier. In an optical print head provided with an imaging element array in which each aperture is formed and a light shielding member in which each opening is formed corresponding to each imaging element, the arrangement pitch of the imaging element array is P, and the light shielding When the aperture diameter in the arrangement direction of each aperture of the member is Apx,
P ≦ 1mm
0.8 ≦ Apx / P <1.0
The imaging element array is formed by arranging a plurality of equivalent imaging elements integrally, and the light shielding member is opaque on both the light emitting element array side and the image carrier side of the imaging element array. Print using material Or It is formed integrally with the imaging element array by coating.
[0013]
Claim 2 The described invention is claimed. 1 In the invention described above, the imaging element has a lens surface, and the lens surface has an aspherical shape.
[0018]
Claim 3 The invention described in the above is an image forming apparatus for forming an image by an electrophotographic process. Or 2 The optical print head described is used as an exposure unit.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of an optical print head and an image forming apparatus using the same according to the present invention will be described below with reference to the drawings. As shown in FIG. 1, the imaging element array 1 forms an image of a light beam from each light emitting element of a light emitting element array (not shown) in which a plurality of light emitting elements are arranged as a light spot on an image carrier. For this purpose, there are two pairs of substantially perpendicular surfaces, an incident surface 1a positioned on the incident side which is the light emitting element array side and an output surface 1b positioned on the output side which is the scanned surface side of the image carrier. A plurality of imaging elements formed integrally with the total reflection surface 1c are arranged in the α direction, and have an erecting equal magnification system in the arrangement direction (α direction) of the imaging elements. It is.
[0020]
The two pairs of total reflection surfaces 1c constitute a roof prism that forms an angle of 90 degrees with each other, do not act on image formation, and are inclined by 45 degrees with respect to the incident optical axis. In addition, a boundary portion between the incident surface 1a and the exit surface 1b of the imaging element and each edge of the entrance surface 1a and the exit surface 1b of the imaging element, which are parallel to the α direction that is the arrangement direction of the imaging elements. A rod-shaped rib portion 1d for enhancing positional accuracy during reinforcement and assembly is integrally formed on the edge portion along the α direction. In this embodiment, the imaging element array 1 uses a roof prism lens array (RPLA) formed by integrally molding a roof prism lens array, an incident side lens array, and an exit side lens array. 2 shows the imaging element array 1 when viewed from the β direction parallel to the α direction which is the arrangement direction of the imaging elements in FIG. 1, and FIG. 3 shows a cross section in the α direction. ing.
[0021]
Since the imaging element array 1 is an erecting equal-magnification system as described above, the shapes of the entrance surface 1a and the exit surface 1b of the imaging element are equal and optically equivalent, and the light emission of the light emitting element array The distance from the object point on the element surface to the incident surface 1a is equal to the distance from the exit surface 1b to the image point on the scanned surface of the image carrier. In the illustrated imaging element, both the entrance surface 1a and the exit surface 1b, which are lens surfaces, are formed in an arc shape, but may be formed in a non-arc shape. By forming the entrance surface 1a and the exit surface 1b into a non-arc shape, it is possible to further improve the imaging performance at the lens periphery.
[0022]
The imaging element array 1 is set to satisfy P ≦ 1 mm, where P is the arrangement pitch of the imaging elements. In image formation using the solid writing method, vertical stripes of the image are a problem. This vertical stripe is generated with the arrangement cycle of the imaging element array, and can be made inconspicuous by shifting the arrangement cycle of the imaging element array from a frequency band that is most sensitive to humans. The frequency band that humans feel most sensitively is known to be about 0.5 to 1 cycle / mm. Therefore, the arrangement pitch P of the imaging elements of the imaging element array 1 is set to 1 mm or less. As a result, vertical stripes can be made inconspicuous and a good image can be obtained.
[0023]
Further, since the arrangement pitch P of the imaging elements of the imaging element array 1 is 1 mm or less, the lens diameter in the arrangement direction of the imaging elements can be 1 mm or less. In the spherical single lens, as the lens diameter increases, the spherical aberration characteristic at the periphery of the lens is significantly reduced as compared with the vicinity of the optical axis of the lens. In “Seidel's five aberrations” (see “Introduction to Imaging Optics” on page 68), when the entrance pupil radius is R, the spherical aberration is R ^Three Coma is proportional to R ² It is known to be proportional to Therefore, by setting the lens diameter in the arrangement direction of the image forming elements to 1 mm or less, it is possible to suppress deterioration in image forming performance at the periphery of the lens.
[0024]
A light beam emitted from one point of the light emitting element surface of the light emitting element array (not shown) enters the incident surface 1a of the imaging element array 1, is sequentially reflected by the two total reflection surfaces 1c, and is emitted from the emission surface 1b. It reaches the surface to be scanned of the image carrier. The incident optical axis and the outgoing optical axis are substantially 90 degrees. Due to the imaging action of the incident surface 1a and the exit surface 1b, one point image on the light emitting element surface is connected to one point on the scanned surface of the image carrier corresponding thereto. In this way, a large number of light emitting element surface images arranged in the light emitting element array are connected in a line on the scanned surface of the image carrier. This line direction is the main scanning direction, and the image carrier is scanned by controlling on / off of a large number of light emitting elements arranged in the light emitting element array while performing sub-scanning by rotating the image carrier. An image can be formed on the surface.
[0025]
FIG. 4 shows a cross section of the imaging element array 1 in the α direction, similarly to FIG. 3. As shown in FIG. 4, the imaging element array 1 includes a light emitting element array side and an image carrier side of the imaging element array 1 so as to block a boundary portion 11 between the adjacent imaging elements. In other words, the light shielding members 12 are separately formed on the front surfaces of both the entrance surface 1a and the exit surface 1b. More specifically, the light shielding member 12 has a plurality of openings 12a formed so as to correspond to the entrance surface 1a and the exit surface 1b of each imaging element, and the openings 12a adjacent to each other in the arrangement direction. 12b between the opening 12a and the opening 12a blocks the boundary portion 11. As the light shielding member 12, a thin flat plate such as a metal flat plate in which a plurality of openings 12a are formed corresponding to the incident surface 1a and the emission surface 1b of each imaging element can be used. FIG. 4 shows only the light shielding member 12 provided on the front surface of the emission surface 1b.
[0026]
Further, as described above, since the arrangement pitch P of the imaging elements of the imaging element array 1 is P ≦ 1 mm, the lens diameter in the arrangement direction of the imaging elements of the imaging element array 1 is 1 mm or less, Since the deterioration of the imaging performance is suppressed to be small, therefore, the aperture diameter in the arrangement direction of the apertures 12a of the light shielding member 12 can be made sufficiently large. That is, when the aperture diameter in the arrangement direction of the openings 12a of the light shielding member 12 is Apx,
0.8 ≦ Apx / P <1.0
Can be set to satisfy. Note that Apx <Lx, where Lx is the lens diameter in the arrangement direction of the imaging elements.
[0027]
According to the above embodiment, when the arrangement pitch P of the imaging elements of the imaging element array 1 is P ≦ 1 mm and the aperture diameter in the arrangement direction of the openings 12a of the light shielding member 12 is Apx, Since 0.8 ≦ Apx / P <1.0 is satisfied, the aperture diameter in the arrangement direction of the openings 12a of the light shielding member 12 is set to the arrangement pitch P of the imaging elements of the imaging element array 1. The transmission efficiency of the imaging element can be improved. In addition, since the arrangement pitch P of the imaging elements in the imaging element array 1 is P ≦ 1 mm, the vertical stripes are made inconspicuous by shifting the arrangement period of the imaging element array from the frequency band that is most sensitive to humans. The imaging performance of the imaging element can be improved.
[0028]
The light shielding member 12 may be provided only on the incident surface 1a on the light emitting element array side, or may be provided only on the emission surface 1b on the image carrier side of the imaging element array 1. However, as described above, the light shielding performance can be further improved by providing the light shielding members 12 on both the entrance surface 1a and the exit surface 1b. Further, when the light shielding member 12 is provided on both the incident surface 1a and the exit surface 1b, the light shielding member 12 provided on the incident surface 1a on the light emitting element array side of the imaging element array 1 and the imaging element array 1 The light shielding member 12 provided on the light exit surface 1b on the image carrier side can be provided separately or integrally. When provided integrally, for example, a thin flat plate such as an L-shaped metal flat plate in which a plurality of openings 12 a are formed on each surface can be used as the light shielding member 12.
[0029]
Next, the light shielding member will be described with some modifications. As shown in FIG. 5, the imaging element array 1 includes a light emitting element array side and an image carrier side of the imaging element array 1 so as to block a boundary portion 11 between adjacent imaging elements. In other words, the light shielding members 13 are integrally formed on the front surfaces of both the entrance surface 1a and the exit surface 1b. More specifically, the light shielding member 13 is the front surface of the entrance surface 1a or the exit surface 1b, and is integrally formed on the boundary portion 11 between the adjacent image forming elements. Yes. Therefore, the gap between the light shielding member 13 and the light shielding member 13 in the arrangement direction is an opening 13 a of the light shielding member 13. As the light shielding member 13, an opaque material ink or the like can be used. FIG. 5 shows only the light shielding member 13 provided on the front surface of the emission surface 1b.
[0030]
Further, as described above, since the arrangement pitch P of the imaging elements of the imaging element array 1 is P ≦ 1 mm, the lens diameter in the arrangement direction of the imaging elements of the imaging element array 1 is 1 mm or less, Since the deterioration of the imaging performance is kept small, therefore, the aperture diameter in the arrangement direction of the apertures 13a of the light shielding member 13 can be made sufficiently large. That is, when the aperture diameter in the arrangement direction of the openings 13a of the light shielding member 13 is Apx,
0.8 ≦ Apx / P <1.0
Can be set to satisfy. Note that Apx <Lx, where Lx is the lens diameter in the arrangement direction of the imaging elements.
[0031]
FIG. 6 shows another modification of the light shielding member. As shown in FIG. 6, ribs 14 projecting from both the entrance surface 1 a and the exit surface 1 b are formed at the boundary between the imaging elements and the imaging elements of the imaging element array 1. A light shielding member 15 is integrally formed on each rib 14. Therefore, the gap between the light shielding member 15 and the light shielding member 15 in the arrangement direction, in other words, the gap between the rib 14 and the rib 14 is the opening 15a of the light shielding member 15. The light shielding member 15 is printed using an opaque material. Or It can be formed by coating. In the case shown in FIG. 6, the light shielding member 15 is formed only on the upper surface of the rib 14, but it can also be formed on the side surface of the rib 14. FIG. 5 shows only the light shielding member 15 provided on the front surface of the emission surface 1b.
[0032]
Further, as described above, since the arrangement pitch P of the imaging elements of the imaging element array 1 is P ≦ 1 mm, the lens diameter in the arrangement direction of the imaging elements of the imaging element array 1 is 1 mm or less, Since the deterioration of the imaging performance is kept small, therefore, the aperture diameter in the arrangement direction of the apertures 15a of the light shielding member 15 can be made sufficiently large. That is, when the aperture diameter in the arrangement direction of the openings 15a of the light shielding member 15 is Apx,
0.8 ≦ Apx / P <1.0
Can be set to satisfy. Note that Apx = Lx, where Lx is the lens diameter in the arrangement direction of the imaging elements.
[0033]
What has been described so far is the opening in the arrangement direction of the light shielding members. Next, the opening in the direction orthogonal to the arrangement direction of the light shielding members will be described. FIG. 8 shows the imaging element array 1 when viewed from the β direction parallel to the α direction, which is the arrangement direction of the imaging elements, as in FIG. As shown in FIG. 8, in the imaging element array 1, light shielding members 16 are separately formed on the front surfaces of both the entrance surface 1a and the exit surface 1b. More specifically, the light shielding member 16 has openings 16a formed so as to correspond to the incident surface 1a and the exit surface 1b of the respective imaging elements. The light shielding member 16 includes the entrance surface 1a and the exit surface. It is provided in the vicinity of the rib portion 1d extending in the arrangement direction so as to block the peripheral portion of the lens surface of the surface 1b along the arrangement direction. As the light shielding member 16, a thin flat plate such as a metal flat plate in which an opening 16a is formed corresponding to the incident surface 1a and the emission surface 1b of each imaging element can be used.
[0034]
Further, as described above, since the arrangement pitch P of the imaging elements of the imaging element array 1 is P ≦ 1 mm, the aperture diameter in the direction orthogonal to the arrangement direction of the openings 16a of the light shielding member 16 is set to Apy. When
Apy ≧ Axx,
1.0 ≦ Apy / P ≦ 1.75
Can be set to satisfy. If the lens diameter in the direction orthogonal to the arrangement direction of the imaging elements is Ly, Apy <Ly.
[0035]
According to the above embodiment, when the opening diameter in the direction orthogonal to the arrangement direction of the openings 16a of the light shielding member 16 is Apy, 1.0 ≦ Apy / P ≦ 1.75 is satisfied. Therefore, the aperture diameter in the direction orthogonal to the arrangement direction of the openings 16a of the light shielding member 16 can be increased with respect to the arrangement pitch P of the imaging elements of the imaging element array 1, and the transmission of the imaging elements Efficiency can be improved.
[0036]
Further, the light shielding member 16 can be provided only on the incident surface 1 a on the light emitting element array side, or can be provided only on the emission surface 1 b on the image carrier side of the imaging element array 1. However, as described above, the light shielding performance can be further improved by providing the light shielding members 16 on both the entrance surface 1a and the exit surface 1b. When the light shielding member 16 is provided on both the incident surface 1a and the exit surface 1b, the light shielding member 16 provided on the incident surface 1a on the light emitting element array side of the imaging element array 1 and the imaging element array 1 The light shielding member 16 provided on the exit surface 1b on the image carrier side can be provided separately, or can be provided integrally as shown in FIG. When provided integrally, a thin flat plate such as an L-shaped metal flat plate having openings 16a formed on each surface as shown in FIG.
[0037]
Further, in the structure shown in FIG. 10, the light shielding member 16 is integrally provided on the rib portion 1d so as to block the peripheral portion along the arrangement direction of the lens surfaces of the entrance surface 1a and the exit surface 1b. As shown in FIG. 9, it is possible to cover only the ribs 1d without blocking the peripheral portions of the lens surfaces of the entrance surface 1a and the exit surface 1b along the arrangement direction. That is, the light shielding member 16 can be provided so that Apy = Ly. In the case shown in FIG. 9, the light shielding member 16 is printed using an opaque material. Or It can be formed by coating. Further, in the case shown in FIG. 9, the light shielding member 16 is formed only on the upper surface of the rib 1d, but it can also be formed on the side surface of the rib 1d.
[0038]
Next, the arrangement pitch P of the imaging element array 1 is 0.6 mm, the opening diameter of the light shielding member in the arrangement direction is 0.5 mm, and the opening diameter in the direction orthogonal to the arrangement direction is 0.6 mm. Specific optical data in this case will be listed. As shown in FIG. 7, the distance from the object point on the light emitting element surface of the light emitting element array to the incident surface 1a of the imaging element array 1 is L1, and the image carrier is scanned from the exit surface 1b. The distance to the image point of the surface is L2, the distance on the optical axis from the incident surface 1a to the two pairs of total reflection surfaces 1c is D1, and the distance on the optical axis from the two pairs of total reflection surfaces 1c to the emission surface 1b The distance is D2.
[0039]
(Unit: mm)
L1 = L2 = 7.0
D1 = D2 = 0.7
Refractive index = 1.525
Arrangement pitch = 0.6
Radius of curvature of entrance surface 1a = 3.675
Radius of curvature of exit surface 1b = −3.675
[0040]
At this time, assuming a light-emitting element array of 600 dpi and each light-emitting element as a complete diffusion light source of 20 μm × 20 μm, the image height H = 0 on the scanning surface of the image carrier (the optical axis position of the imaging element) Beam spot diameter (1 / e) ² As for (diameter), a simulation result that the arrangement direction is 42 μm and the direction orthogonal to the arrangement direction is 40 μm is obtained, and a good beam spot diameter is obtained despite the large aperture diameter in the arrangement direction.
[0041]
Next, the arrangement pitch P of the imaging element array 1 is 0.6 mm, the opening diameter of the light shielding member in the arrangement direction is 0.5 mm, and the opening diameter in the direction orthogonal to the arrangement direction is 1.0 mm. Specific optical data in this case will be listed. As in the optical data, as shown in FIG. 7, the distance from the object point on the light emitting element surface of the light emitting element array to the incident surface 1a of the imaging element array 1 is L1, and the exit surface of the imaging element array 1 L2 is the distance from 1b to the image point on the scanned surface of the image carrier, D1 is the distance on the optical axis from the incident surface 1a to the two pairs of total reflection surfaces 1c, and the light is emitted from the two pairs of total reflection surfaces 1c. The distance on the optical axis to the surface 1b is D2.
[0042]
(Unit: mm)
L1 = L2 = 8.0
D1 = D2 = 1.5
Refractive index = 1.525
Arrangement pitch = 0.6
Radius of curvature of entrance surface 1a = 4.200
Radius of curvature of exit surface 1b = -4.200
[0043]
The incident surface 1a and the exit surface 1b are both aspherical and can be represented by the following general aspherical expression.
X (H) = H ² / [R + R√ {1- (1 + K) (H / R) ² }]
+ AH ^Four + BH ⁶ + CH ⁸ + DH ^Ten + ...
R: paraxial radius of curvature, H: lens height, K: estimated number of circles,
A, B, C, D, ...: Constant
Aspherical parameter K = 6.944 of entrance surface 1a
A = −0.01745
Aspherical parameter K = 6.944 of the exit surface 1b
A = 0.01745
[0044]
At this time, assuming a 1200 dpi light emitting element array, the image height H = 0 on the scanning surface of the image carrier when each light emitting element is a 10 μm × 10 μm complete diffusion light source (the optical axis position of the imaging element) Beam spot diameter (1 / e) ² (Diameter) is a good beam spot diameter despite the large aperture diameter in the direction orthogonal to the array direction, with the simulation result that the array direction is 13 μm and the direction orthogonal to the array direction is 16 μm. Is obtained.
[0045]
The optical print head can be used as an exposure unit of an image forming apparatus that forms an image by an electrophotographic process. As shown in FIG. 11, around the image carrier 72, there are a charging unit 90, an exposure unit 91 composed of an optical print head comprising a light emitting element array and an image forming element array, a developing unit 92, a transfer unit 93, A fixing unit 94, a charge eliminating unit 95, a cleaner unit 96, and the like are arranged. As is well known, in an electrophotographic process, a latent image is formed on an image carrier 72 by irradiating a light spot from an optical print head onto the image carrier 72 (exposure), and toner is attached to the latent image. Thus, a toner image is formed (development), the toner image is transferred to a recording paper (transfer), and fixed on the recording paper by pressure or heat (fixing) to form an image.
[0046]
【The invention's effect】
According to the first aspect of the present invention, in order to form a light-emitting element array in which a plurality of light-emitting elements are arrayed and light beams from the plurality of light-emitting elements as light spots on the image carrier, respectively, In an optical print head comprising an imaging element array in which image elements are arranged and a light shielding member in which each opening is formed corresponding to each imaging element, the arrangement pitch of the imaging element arrays is P, When the aperture diameter in the arrangement direction of each opening of the light shielding member is Apx,
P ≦ 1mm
0.8 ≦ Apx / P <1.0
Therefore, the transmission efficiency of the imaging element can be improved and the imaging performance of the imaging element can be improved.
Further, since the light shielding member is provided on both the light emitting element array side and the image carrier side of the imaging element array, the light shielding performance can be further improved. In the imaging element array, a plurality of equivalent imaging elements are integrally formed and arranged, and the light shielding member is printed using an opaque material. Or Since it is formed integrally with the imaging element array by coating, position adjustment between the light shielding member and the imaging element array can be made unnecessary.
[0048]
Claim 2 According to the described invention, the claims 1 In the invention described above, since the imaging element has a lens surface and the lens surface is aspherical, the imaging performance of the imaging element can be further improved.
[0053]
Claim 3 According to the described invention, in an image forming apparatus for forming an image by an electrophotographic process, Or 2 Since the described optical print head is used as an exposure unit, the light output of the exposure unit can be increased, the printing speed can be increased, and the light output of the light emitting element array can be reduced, thereby saving energy. Can be achieved.
[Brief description of the drawings]
FIG. 1 is a partial perspective view showing an imaging element array applicable to an embodiment of an optical print head and an image forming apparatus using the same according to the present invention.
FIG. 2 is a side view showing the imaging element array.
FIG. 3 is a transverse sectional view showing the imaging element array.
FIG. 4 is a cross-sectional view showing the imaging element array provided with a light shielding member applicable to the present invention.
FIG. 5 is a cross-sectional view showing the imaging element array provided with another light shielding member.
FIG. 6 is a transverse sectional view showing the imaging element array in which another light shielding member is provided.
FIG. 7 is a side view showing an optical arrangement of the imaging element array.
FIG. 8 is a cross-sectional view showing the imaging element array provided with still another light shielding member.
FIG. 9 is a cross-sectional view showing the imaging element array provided with still another light shielding member.
FIG. 10 is a cross-sectional view showing the imaging element array provided with still another light shielding member.
FIG. 11 is a layout diagram showing various units arranged around the image carrier.
FIGS. 12A and 12B show an example of an imaging element array to which a conventional aperture member is applied, in which FIG. 12A is a partial perspective view of the imaging element array, FIG. 12B is a partial perspective view of the aperture member, and FIG. It is a cross-sectional view of the imaging element array to which is attached.
[Explanation of symbols]
1 Imaging element array
1a Incident surface
1b Outgoing surface
1c Total reflection surface
1d rib part
11 border
12 Shading member
12a opening
13 Shading member
13a opening
14 Ribs
15 Shading member
15a opening
16 Shading member
16a opening
72 Image carrier
90 Charging unit
91 Exposure unit
92 Development Unit
93 Transfer unit
94 Fixing unit
95 Static elimination unit
96 Cleaner unit

Claims (3)

A light emitting element array in which a plurality of light emitting elements are arranged;
An imaging element array in which a plurality of imaging elements are arranged in order to form light beams from the plurality of light emitting elements as light spots on the image carrier;
In an optical print head provided with a light shielding member in which each opening is formed corresponding to each imaging element,
When the arrangement pitch of the imaging element array is P, and the aperture diameter in the arrangement direction of the openings of the light shielding member is Apx,
P ≦ 1mm
0.8 ≦ Ap x / P <1.0
The filling,
In the imaging element array, a plurality of equivalent imaging elements are integrally formed and arranged.
The light shielding member is formed integrally with the imaging element array by printing or coating using an opaque material on both the light emitting element array side and the image carrier side of the imaging element array. Print head.   2. The optical print head according to claim 1, wherein the imaging element has a lens surface, and the lens surface has an aspherical shape. In an image forming apparatus that forms an image by an electrophotographic process,
An image forming apparatus using the optical print head according to claim 1 as an exposure unit.

Images