JP2009246312A - Light-emitting device array and image forming apparatus equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-resolution light-emitting device array that can prevent the adverse effect on a light-emitting section close to an end face formed by dicing, and to provide an image forming apparatus equipped with the same. <P>SOLUTION: The light-emitting device array 11 includes a substrate 12 and a plurality of light-emitting sections 13. The light-emitting sections 13 are formed on the substrate 12 in a line and emit light with the power supplied. Line-directional intervals among some of the plurality of light-emitting sections 13 are gradually decreased as they go in one direction of the line. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a light emitting element array that emits light when supplied with electric power, and an image forming apparatus that forms an image for recording on a recording sheet.

  FIG. 8 is a cross-sectional view of the light emitting diode array chip 1 according to the prior art. When the light emitting diode array is cut out by dicing, chipping of the light emitting part called chipping may occur. In order to prevent this, a technique for forming the inverted mesa shape 3 on the chip end surface 2 is known (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 06-029572

  When the distance between the chip end surface 2 formed by dicing and the light emitting portion 4 adjacent to the chip end surface 2 is short, crystal defects are likely to occur on the chip end surface 2 formed by dicing. As a result, the light emitting unit 4 closest to the end face may be short-circuited. In particular, when manufacturing a light emitting element array and an image forming apparatus with high resolution, the distance between the chip end surface 2 formed by dicing and the light emitting portion 4 adjacent to the chip end surface 2 tends to be shortened, and the resolution should be increased. As a result, it becomes difficult to manufacture the light emitting part 4 located at the end most with a high yield.

  An object of the present invention is to provide a light-emitting element array with high resolution and an image forming apparatus including the same, which can prevent adverse effects on a light-emitting portion adjacent to an end surface formed by dicing.

The light emitting element array of the present invention has the following configuration (1).
(1) A substrate and a plurality of light emitting units are included. The light emitting units are provided in a row on the substrate, and emit light when power is supplied. In addition, as for some of the plurality of light emitting units, the interval in the column direction becomes gradually narrower toward one side in the column direction.

Moreover, the light emitting element array of this invention is equipped with the structure of (2) shown below.
(2) A substrate and a plurality of light emitting units are included. The light emitting units are provided in a row on the substrate, and emit light when power is supplied. Moreover, as for some ones of several light emission parts, the dimension of a column direction becomes small gradually as it goes to the column direction one side.

The image forming apparatus of the present invention has the following configuration (3).
(3) A light emitting element array, an electrophotographic photosensitive member, a developing supply unit, a transfer unit, and a fixing unit are provided. The electrophotographic photosensitive member is irradiated with light emitted from the light emitting element array. The development supply means supplies a developer to the electrophotographic photosensitive member. The transfer unit transfers an image formed by the developer on the electrophotographic photosensitive member to a recording sheet. The fixing unit fixes the developer transferred to the recording sheet.

  In the light emitting element array of the present invention having the configuration of (1), the interval in the column direction is gradually narrowed as a part of the plurality of light emitting units goes to one side in the column direction. Thereby, the space | interval of the row direction of the edge part of a row direction of a board | substrate and the light emission part most located in a row direction can be enlarged. Therefore, it is possible to prevent the light emitting portion from being chipped when the substrate is cut by dicing. Further, by dicing, the influence of impurities entering the substrate from one end surface in the column direction on the light emitting portion can be reduced. Therefore, the yield concerning manufacture of a light emitting element array can be made high.

  If the distance between the light emitting portions in the column direction is constant, if the resolution is reduced, the distance in the column direction between one end of the substrate in the column direction and the light emitting portion located at the most in the column direction is reduced. Since the interval in the column direction of the section gradually changes, even if the resolution is reduced, it is possible to prevent the interval in the column direction between the one end portion in the column direction of the substrate and the light emitting portion located closest to the column direction from being reduced. Or it can be prevented.

  Therefore, it is possible to achieve both the prevention of an adverse effect on the light emitting unit located at one side in the column direction and the reduction of the resolution. In addition, since the interval in the column direction between the light emitting units gradually changes as the position in the column direction changes, the intensity of light emitted from the light emitting element array changes rapidly as the position in the column direction changes. Can be prevented.

  In the light-emitting element array of the present invention having the configuration (2), the dimension in the column direction gradually decreases as some of the plurality of light-emitting portions go to one side in the column direction. Thereby, the space | interval of the row direction of the edge part of a row direction of a board | substrate and the light emission part most located in a row direction can be enlarged. Therefore, it is possible to prevent the light emitting portion from being chipped when the substrate is cut by dicing. Further, by dicing, the influence of impurities entering the substrate from one end surface in the column direction on the light emitting portion can be reduced. Therefore, the yield concerning manufacture of a light emitting element array can be made high.

  If the distance between the light emitting portions in the column direction is constant, if the resolution is reduced, the distance in the column direction between one end of the substrate in the column direction and the light emitting portion located at the most in the column direction is reduced. Since the interval in the column direction of the section gradually changes, even if the resolution is reduced, it is possible to prevent the interval in the column direction between the one end portion in the column direction of the substrate and the light emitting portion located closest to the column direction from being reduced. Or it can be prevented.

  Therefore, it is possible to achieve both the prevention of an adverse effect on the light emitting unit located at one side in the column direction and the reduction of the resolution. In addition, since the dimension in the column direction of the light emitting section gradually changes with the change in the position in the column direction, the intensity of light emitted from the light emitting element array rapidly changes with the change in the position in the column direction. This can be prevented.

  According to the image forming apparatus of the present invention having the configuration of (3), the distance in the column direction between the one end of the substrate in the column direction and the light emitting unit positioned most in the column direction can be increased. By dicing, it is possible to reduce the influence of impurities that have entered the substrate from one end surface in the column direction on the light emitting portion. Therefore, it is possible to prevent the light intensity from the light emitting portion located at one side in the column direction from decreasing. Thereby, it is possible to suppress a decrease in image accuracy at one end in the column direction of the light emitting element array.

  Further, since the yield related to the manufacture of the light emitting element array can be increased, the manufacturing cost related to the image forming apparatus can be reduced. Moreover, even if the resolution is reduced, it is possible to prevent adverse effects on the light emitting portion located in the most column direction, so that the light intensity from the light emitting portion located in the most row direction can be suppressed and the resolution can be reduced. High image forming apparatus can be realized at the same time. In addition, since the intensity of light emitted from the light emitting element array can be prevented from changing suddenly with the change in the position in the column direction, the accuracy in image formation is improved by the change in the position in the column direction. A sudden change can be prevented.

  Hereinafter, a plurality of embodiments for carrying out the present invention will be described with reference to the drawings. In the following description, parts corresponding to matters already described in the forms preceding each form may be denoted by the same reference numerals, and overlapping descriptions may be omitted. When only a part of the configuration is described, the other parts of the configuration are the same as those described in the preceding section.

The following description includes descriptions of the light emitting element array 11 and the image forming apparatus 15.
(First embodiment)
FIG. 1 is a plan view comparing the light emitting element array 11 according to the first embodiment of the present invention with the light emitting element array 11 according to the prior art. In any of the light emitting element arrays 11 shown in FIG. 1, the plurality of light emitting units 13 are arranged corresponding to a resolution of 1200 dpi (dots per inch). In FIG. 1, a plan view of the plurality of light emitting elements 10 arranged in the present embodiment is shown in the upper stage, and a plan view of the plurality of light emitting elements 10 arranged in the conventional technique is shown in the lower stage. The light emitting element 10 according to the first embodiment emits light when operated by being supplied with electric power. The light emitting element array 11 includes a substrate 12 and a plurality of light emitting units 13. The light emitting units 13 are provided in a row on the substrate 12 and emit light when supplied with electric power. In addition, as for some of the plurality of light emitting units 13, the interval in the column direction becomes gradually narrower toward one side in the column direction.

  The light emitting element array 11 further includes a light emitting unit side electrode 14. The light emitting unit side electrode 14 is connected to the surface of the light emitting unit 13 on the side opposite to the substrate 12, and forms a supply path for supplying power to the light emitting unit 13. The light emitting portion side electrode 14 has an electrode end portion 17, and the electrode end portion 17 is formed in contact with the light emitting portion 13. The electrode end portion 17 formed in contact with the light emitting portion 13 whose interval in the column direction is gradually narrowed is formed closer to the other side in the column direction than the central portion in the column direction of each light emitting portion 13. A potential difference between the light emitting unit side electrode 14 and the substrate 12, specifically, a potential difference between the electrode end 17 and the substrate 12 is applied to the light emitting unit 13.

  The electrode end portion 17 is formed to extend in a direction parallel to the substrate 12. When the direction in which the electrode end portion 17 is formed to extend long is referred to as a “longitudinal direction”, the longitudinal direction is set to be perpendicular to the thickness direction and the column direction of the substrate 12. The light emitting portion side electrode 14 includes a base portion 16 and an electrode end portion 17, and the base portion 16 and the electrode end portion 17 constitute a supply path when electric power is supplied to the light emitting portion 13.

  The light emitting element array 11 includes a plurality of light emitting elements 10, and each light emitting element 10 includes a light emitting unit 13, a light emitting unit side electrode 14, and a substrate 12. However, since the substrates 12 included in the plurality of light emitting elements 10 are shared by the plurality of light emitting elements 10 in one light emitting element array 11, one substrate 12 is provided in one light emitting element array 11. The light emitting element array 11 is mounted on an optical print head included in the electrophotographic image forming apparatus 15 and emits light toward the photosensitive drum, thereby exposing the surface portion of the photosensitive drum. The light emitting element array 11 constitutes an optical print head together with a lens array in which a plurality of lenses are arranged.

  In the present embodiment, the substrate 12 is made of an n-type semiconductor, and a plurality of light emitting units 13 are arranged in a row on one substrate 12. The plurality of light emitting units 13 are arranged side by side on one of the two surfaces of the substrate 12 perpendicular to the thickness direction of the substrate 12. Of the thickness direction of the substrate 12, the direction in which the light emitting unit 13 is arranged is referred to as “one in the thickness direction”, and the direction opposite to one in the thickness direction is referred to as “the other in the thickness direction”. A back electrode 18 is provided on the other side of the substrate 12 in the thickness direction. The back electrode 18 is disposed in contact with the substrate 12 and is electrically connected to the substrate 12.

  The light emitting unit 13 includes a semiconductor layer 19 on which a plurality of types of semiconductors are stacked. The light emitting unit 13 is formed in a rectangular parallelepiped shape, and each semiconductor layer 19 is formed in a flat plate shape. Each semiconductor layer 19 is laminated in the thickness direction with its thickness direction coinciding with the thickness direction of the substrate 12. In the present embodiment, the light emitting unit 13 includes a first n-type semiconductor layer 21, a first p-type semiconductor layer 22, a second n-type semiconductor layer 23, a second p-type semiconductor layer 24, and an ohmic contact layer 25. The first n-type semiconductor layer 21 is made of an n-type semiconductor, and is arranged in contact with the substrate 12 from one side in the thickness direction. The first p-type semiconductor layer 22 is made of a p-type semiconductor, and is arranged in contact with the first n-type semiconductor layer 21 from one side in the thickness direction. The second n-type semiconductor layer 23 is made of an n-type semiconductor, and is disposed in contact with the first p-type semiconductor layer 22 from one side in the thickness direction. The second p-type semiconductor layer 24 is made of a p-type semiconductor, and is arranged in contact with the second n-type semiconductor layer 23 from one side in the thickness direction. The light emitting unit side electrode 14 is connected to the light emitting unit 13 from one side in the thickness direction than the light emitting unit 13.

  In the first embodiment, the light emitting unit 13 is a light emitting thyristor, and is driven by a dynamic driving method to emit light. The cathode is used as a common terminal by the back electrode 18, and the anode is connected in a matrix of m × n (m and n are natural numbers), and the drive signals are switched in a time division manner to cause each LED to emit light. In addition to the terminals connected to the anode and the cathode, the light emitting thyristor is provided with a gate terminal connected to a gate through which almost no current flows. The gate is provided in each light emitting thyristor, and a voltage for switching between a state in which a current for light emission flows and a state in which the current does not flow is applied. Thereby, each light emission part 13 can be controlled separately.

  The ohmic contact layer 25 is interposed between the light emitting unit side electrode 14 and the semiconductor layer 19, and causes resistance generated between the light emitting unit side electrode 14 and the semiconductor layer 19 to be applied regardless of an applied voltage and a generated current. Keep constant. For example, in another embodiment, the light emitting unit side electrode 14 and the semiconductor layer 19 may be directly in contact with each other without providing the ohmic contact layer 25. However, the resistance generated at the contact interface between the light emitting unit side electrode 14 and the semiconductor layer 19 may vary depending on the voltage and current applied between the light emitting unit side electrode 14 and the semiconductor layer 19. The magnitude of the current generated in the semiconductor layer 19 is generated in the light emitting unit 13 when the light emitting unit side electrode 14 is proportional to the voltage applied to the light emitting unit 13 than in the non-linear relationship. Easy to control the current. By interposing the ohmic contact layer 25, the resistance value generated between the light emitting unit side electrode 14 and the semiconductor layer 19 is kept constant, and is generated in the semiconductor layer 19 by application of a voltage from the light emitting unit side electrode 14. The current value can be easily controlled.

  When viewed in the thickness direction, the light emitting portion 13 is a rectangle of 20 μm × 9 μm. The 9 μm side coincides with the column direction, and the 20 μm side coincides with the longitudinal direction of the electrode end portion 17. For any light emitting part 13 included in the light emitting element array 11, the side of 9 μm coincides with the column direction, and the side of 20 μm coincides with the longitudinal direction of the electrode end part 17. The dimension of the light emitting element 10 in the thickness direction is set to 1 μm to 6 μm, and all the light emitting portions 13 arranged in the column direction are formed to have the same size.

  The light emitting part side electrode 14 is arranged in contact with the light emitting part 13 from one side in the thickness direction. The light emitting portion side electrode 14 includes a base portion 16 and an electrode end portion 17, and the base portion 16 is disposed in contact with an end portion located on one side in the longitudinal direction of the light emitting portion 13. The electrode end portion 17 is formed in an elongated flat plate shape, and the thickness direction of the electrode end portion 17 is arranged to coincide with the thickness direction of the substrate 12. The longitudinal dimension of the electrode end 17 is 20 μm or less, the other surface in the thickness direction of the electrode end 17 is in contact with the light emitting part 13, and one longitudinal direction of the electrode end 17 continues to the base 16. The dimension of the base portion 16 in the column direction is set to a length equal to or shorter than the dimension of the light emitting portion 13 in the column direction, and the base portion 16 and the electrode end portion 17 form a T shape when viewed in the thickness direction. The dimension in the column direction of each electrode end portion 17 is set to 2 μm.

  The light emitting unit side electrode 14 applies voltage to the light emitting unit 13 using the light emitting unit side electrode 14 as an anode and the back electrode 18 as a cathode. The current flowing through the light emitting unit 13 is generated between the base 16 and the electrode end 17 and the substrate 12 and flows in the thickness direction. The light emitting unit 13 emits light in the thickness direction when a current flows in the thickness direction. Since the other side in the thickness direction of the light emitting unit 13 is in contact with the substrate 12, the light from the light emitting unit 13 is actually emitted toward one side in the thickness direction. Since the light-emitting part side electrode 14 is made of metal and blocks light, the light from the light-emitting part 13 is the remaining part of the one surface part in the thickness direction of the light-emitting part 13 except for the part in contact with the light-emitting part side electrode 14. It is emitted from the surface portion.

  One light emitting element array 11 includes, for example, 60 light emitting elements 10. In the comparative example shown in the lower part of FIG. 1, the distance between the positions of the light emitting elements 10 adjacent to each other in the column direction is 21. Set to 15 μm. The distance between the positions in the column direction center is a so-called distance between the cores. FIG. 2 is a plan view of the light emitting unit 13 arranged in a comparative example similar to the prior art. FIG. 2A is a plan view of the light emitting unit 13 arranged corresponding to 600 dpi in the comparative example, and FIG. 2B is a plan view of the light emitting unit 13 arranged corresponding to 1200 dpi in the comparative example. It is a top view. FIG. 3 is a cross-sectional view of the light emitting element array 11 according to the first embodiment of the present invention.

  In the comparative example, by setting the distance between the positions in the center of the column direction of the light emitting units 13 adjacent in the column direction to 42.3 μm, the resolution corresponds to 600 dpi. In the comparative example, the resolution of 1200 dpi is achieved by setting the distance between the positions in the column direction of the light emitting units 13 in the column direction to 21.15 μm. At 600 dpi, the dimension in the column direction of each light emitting unit 13 is set to 18 μm, and at 1200 dpi, it is set to 9 μm. The distance from the end face of one substrate 12 in the column direction to the light emitting portion 13 closest to the end face, that is, the distance from the face facing the end face of the substrate 12 is set to 9.075 μm at 600 dpi.

  When the resolution is increased from 600 dpi to 1200 dpi, the distance from the end surface of one substrate 12 in the column direction to the light emitting unit 13 closest to the end surface is 3 μm even if the dimension of the light emitting unit 13 in the column direction is halved. . The position of the light emitting unit 13 at 1200 dpi is referred to as “conventional position” 26, and the distance between the central positions in the column direction between the light emitting units 13 adjacent in the column direction at 1200 dpi is referred to as “steady distance”. In the diagram shown in the lower part of FIG. 1 and FIG. 2B, each light emitting element 10 is disposed at the conventional position 26, and the core-to-core distance between the light emitting units 13 is set to a steady distance. On the other hand, in the first embodiment, as shown in the upper part of FIG. 1, the distance between the light emitting units 13 adjacent in the column direction becomes gradually smaller toward one side in the column direction. An area where the core-to-core distance between the light emitting units 13 adjacent in the column direction is set to be shorter than the steady distance is referred to as a “dense area” 27. A region where the core-to-core distance between the light emitting units 13 adjacent in the column direction is set to a steady distance is referred to as a “steady distance region” 28.

  The dense region 27 is set in a range from the light emitting unit 13 located closest to the column direction of the light emitting element array 11 to the center position in the column direction of the light emitting element array 11. In the first embodiment, in the light emitting element array 11 in which 60 light emitting units 13 are arranged in the column direction, the dense region 27 is defined as a region where the five light emitting units 13 on one side in the column direction are located most. Each light emitting element 10 located in the dense region 27 is arranged at a position closer to the other side in the column direction than the conventional position 26. The difference between the position of each light emitting unit 13 and the conventional position 26 of each light emitting unit 13 is set to be larger as it goes to one side in the column direction.

  For example, if the light emitting unit 13 is called a first light emitting unit and a second light emitting unit in order from one side in the column direction, and the dense region 27 is set in a range from the first light emitting unit to the fourth light emitting unit, the fourth light emitting unit. Is located at the other end in the column direction of the dense region 27, and the light emitting portion 13 is disposed at the conventional position 26. When the stationary distance is 21.15 μm and the core-core distance between the fourth light emitting part and the third light emitting part is set to 20.15 μm, the difference between the position of the third light emitting part and the conventional position 26 is 1 μm. Become. When the core-core distance between the third light emitting unit and the second light emitting unit is set to 19.65 μm, the difference between the position of the second light emitting unit and the conventional position 26 is 2.5 μm. When the core-core distance between the second light emitting unit and the first light emitting unit is set to 18.65 μm, the difference between the position of the first light emitting unit and the conventional position 26 is 5 μm.

  As a result, the distance between one end surface in the column direction of the substrate 12 and one end surface in the column direction of the first light emitting unit is 8 μm, which is larger than the resolution of 1200 dpi of the prior art. For example, in another embodiment, the dense region 27 is set in a range between the first light emitting unit and the sixth light emitting unit, and the core-core distance between the sixth light emitting unit and the fifth light emitting unit is set to be larger than the steady distance. The core-core distance between the fifth light-emitting portion and the fourth light-emitting portion is reduced by 1 μm from the steady distance, and the core-core distance between the fourth light-emitting portion and the third light-emitting portion is reduced to a constant distance. And the core-core distance between the third light-emitting part and the second light-emitting part is reduced by 2 μm from the steady distance, and the core-core distance between the second light-emitting part and the first light-emitting part is reduced. The distance may be decreased by 2.5 μm from the steady distance.

  As a result, the distance between the position in the column direction of the first light emitting unit and the conventional position 26 is 7.5 μm, and the distance between one end surface in the column direction of the substrate 12 and one end surface in the column direction of the first light emitting unit is 10.5 μm, which is larger than that of the conventional resolution of 600 dpi. Thus, the wider the dense region 27 is set, the wider the interval region between the light emitting units 13 adjacent in the column direction and the interval between the light emitting units 13 adjacent to the interval region between the light emitting units 13 are. Even if the difference from the length of the region is set small, the distance between one end surface in the column direction of the substrate 12 and one end surface in the column direction of the first light emitting unit can be set larger than that in the prior art. .

  Further, in the present embodiment, the intervals in the column direction of other portions of the plurality of light emitting units 13 are gradually narrowed toward the other in the column direction. In the present embodiment, another dense region different from the dense region 27 is formed on the other side in the column direction with respect to the center position in the column direction of the light emitting element array 11. In another dense region, the core-to-core distance between the light emitting units 13 adjacent to each other in the column direction is set to be shorter than the steady distance, and the light emitting elements 13 are arranged to be light emitting elements from the light emitting unit 13 positioned at the most in the column direction. It is set within the range up to the column direction center position of the array 11. The light emitting element array 11 is formed in plane symmetry with respect to a virtual one plane passing through the column direction center of the light emitting element array 11 and perpendicular to the column direction, and both the dense region 27 and other dense regions are plane symmetrical with respect to this virtual one plane. Become.

  For example, in another embodiment, among the plurality of light emitting units 13 arranged in the column direction, all the ranges where half the light emitting units 13 are located from one end in the column direction are set as the dense region 27 and the plurality of light emitting units 13 arranged in the column direction are arranged. In the case where all of the light emitting units 13 in which the half of the light emitting units 13 are located from the other end in the column direction are set as the dense region 27, the regular interval region may not be formed.

  However, in the light emitting units 13 adjacent to each other in the column direction, the interval between the positions in the column direction center of each light emitting unit 13 corresponds to the set resolution. . Therefore, it is preferable that the distance between the cores of the light emitting units 13 adjacent in the column direction is set to 10.6 μm or more. Further, in the light emitting units 13 adjacent to each other in the column direction, the dense region 27 in which the distance between the center positions in the column direction of the respective light emitting units 13 gradually decreases toward one side in the column direction is among all the light emitting elements 10 arranged in the column direction. It may be set as a range including one half of the column direction.

  In the light emitting element 10 located in the regular distance region 28 and the light emitting element 10 located at the boundary between the dense region 27 on one side in the column direction and the regular interval region, the electrode end 17 is disposed at the center in the column direction of the light emitting element 10. The In the light emitting element 10 located in the dense region 27, the electrode end portion 17 is disposed closer to the other side in the column direction than the column direction center of the light emitting unit 13. The difference in the column direction position between the column direction center of the electrode end 17 and the column direction center of the light emitting unit 13 is set in proportion to the difference between the position of the light emitting unit 13 and the conventional position 26. In the present embodiment, in the one dense region 27 in the column direction, the difference between the position of the light emitting unit 13 and the conventional position 26 is set larger toward the one in the column direction, so in the light emitting element 10 in the dense region 27, The difference in position in the column direction between the column direction center of the electrode end 17 and the column direction center of the light emitting unit 13 also increases toward one side in the column direction.

  When the difference in the column direction position between the column direction center of the electrode end portion 17 and the column direction center of the light emitting unit 13 is referred to as “electrode end portion displacement amount”, the electrode end portion displacement amount is within the dense region 27. It becomes gradually larger as it goes to one side in the row direction. For example, the electrode end portion displacement amount is set to 1 μm for the third light emitting unit, 2 μm for the second light emitting unit, and 3 μm for the first light emitting unit.

  FIG. 4 is a side view showing the configuration of the image forming apparatus 15 according to the first embodiment of the present invention. The image forming apparatus 15 includes a light emitting element array 11, an electrophotographic photosensitive member, a developing supply unit, a transfer unit, and a fixing unit. The electrophotographic photosensitive member is irradiated with light emitted from the light emitting element array 11. The development supply means supplies a developer to the electrophotographic photosensitive member. The transfer unit transfers an image formed by the developer on the electrophotographic photosensitive member to a recording sheet. The fixing unit fixes the developer transferred to the recording sheet.

  The electrophotographic photosensitive member is included in a cylindrical photosensitive drum 90 and is formed as the surface of the outer surface of the photosensitive drum. The electrophotographic photosensitive member is irradiated with light emitted from the light emitting element 10. The transfer unit transfers the image to the recording sheet. The image transferred to the recording sheet is formed on the electrophotographic photosensitive member with a developer. The fixing unit fixes the developer transferred to the recording sheet. In the first embodiment, the image forming apparatus 15 is an electrophotographic image forming apparatus 15, and an optical print head 85 including a plurality of light emitting element arrays 11 is used as an exposure device for the photosensitive drum 90. . The light emitting element array 11 is mounted on a circuit board 86 and constitutes an optical print head 85 which is a light emitting device together with the lens array 88.

  The image forming apparatus 15 is an apparatus that employs a tandem system that forms four color images of Y (yellow), M (magenta), C (cyan), and K (black). Circuit boards 86Y, 86M, 86C, 86K on which the element arrays 11Y, 11M, 11C, and 11K are mounted, lens arrays 88Y, 88M, 88C, and 88K that are condensing means, and a first holder 89Y that holds the lens array 88, 89M, 89C, 89K, four photosensitive drums 90Y, 90M, 90C, 90K, four developer supply means 91Y, 91M, 91C, 91K, transfer belt 92 as transfer means, four cleaners 93Y, 93M, 93C, 93K, four chargers 94Y, 94M, 94C, 94K, a fixing unit 95 and a control unit 96.

  Each light emitting element array 11 mounted on each circuit board 86 is driven based on the color image information of each color by a driving means (not shown). Light from the light emitting element array 11 is condensed and irradiated on the respective photosensitive drums 90Y, 90M, 90C, and 90K through the lens arrays 88Y, 88M, 88C, and 88K of the optical print heads 85Y, 85M, 85C, and 85K. The The lens array 88 includes, for example, a plurality of lenses respectively disposed on the optical axis of the light from the light emitting element array 11 and is configured by integrating these lenses integrally.

  The circuit board 86 and the lens array 88 on which the light emitting element array 11 is mounted are held by the first holder 89. By the first holder 89, alignment is performed so that the light irradiation direction of the light emitting element array 11 and the optical axis direction of the lenses of the lens array 88 substantially coincide.

  Each of the photosensitive drums 90Y, 90M, 90C, and 90K is formed by, for example, attaching a photosensitive layer on the surface of a cylindrical substrate, and each light emitting element array of the optical print heads 85Y, 85M, 85C, and 85K on the outer peripheral surface thereof. An electrostatic latent image forming position at which an electrostatic latent image is formed by receiving light from 11Y, 11M, 11C, and 11K is set.

  At the periphery of each of the photosensitive drums 90Y, 90M, 90C, and 90K, the exposed photosensitive drums 90Y, 90M, 90C, and 90K are sequentially arranged toward the downstream side in the rotation direction with respect to the respective electrostatic latent image forming positions. Developer supplying means 91Y, 91M, 91C, 91K, a transfer belt 92, cleaners 93Y, 93M, 93C, 93K and chargers 94Y, 94M, 94C, 94K are arranged respectively. A transfer belt 92 that transfers an image formed on the photosensitive drum 90 with a developer onto a recording sheet is provided in common to the four photosensitive drums 90Y, 90M, 90C, and 90K.

  The photosensitive drums 90Y, 90M, 90C, and 90K are held by a second holder (not shown), and the second holder and the first holder 89 are relatively fixed.

  The recording sheet is conveyed by the transfer belt 92, and the recording sheet on which an image is formed by the developer is conveyed to the fixing unit 95. The fixing unit 95 fixes the developer transferred to the recording sheet. The photosensitive drums 90Y, 90M, 90C, and 90K are rotated by a rotation driving unit (not shown).

  The control unit 96 supplies a clock signal and image information to a driving unit (not shown), and rotates and drives the photosensitive drums 90Y, 90M, 90C, and 90K, and developer supply units 91Y, 91M, and 91C. 91K, the transfer belt 92, the chargers 94Y, 94M, 94C, 94K, and the fixing unit 95 are controlled.

  According to the first embodiment, a part of the plurality of light emitting units 13 included in the light emitting element array 11 is gradually narrowed in the column direction as going to one side in the column direction. Thereby, the space | interval of the row direction of the edge part of the row direction of the board | substrate 12 and the light emission part 13 most located in a row direction can be enlarged. Therefore, it is possible to prevent the light emitting unit 13 from being chipped when the substrate 12 is cut by dicing. In addition, by dicing, the influence of impurities entering the substrate 12 from one end face in the column direction on the light emitting portion 13 can be reduced. Therefore, the yield concerning manufacture of the light emitting element array 11 can be made high.

  If the interval in the column direction of the light emitting units 13 is constant, if the resolution is reduced, the column direction interval between the one end in the column direction of the substrate 12 and the light emitting unit 13 located at the most in the column direction is reduced. However, since the interval in the column direction of the light emitting units 13 changes gradually, the column direction interval between the one end portion in the column direction of the substrate 12 and the light emitting unit 13 located at the most in the column direction even if the resolution is reduced. Can be suppressed or prevented from becoming smaller.

  Therefore, it is possible to achieve both the prevention of the adverse effect on the light emitting unit 13 located at the most in the column direction and the reduction of the resolution. In addition, since the interval in the column direction between the light emitting units 13 gradually changes as the position in the column direction changes, the intensity of the light emitted from the light emitting element array 11 suddenly increases as the position in the column direction changes. Can be prevented.

  According to the first embodiment, the light emitting element array 11 further includes the light emitting unit side electrode 14, and the light emitting unit side electrode 14 has the electrode end 17. The electrode end 17 is formed in contact with the light emitting unit 13. Among the plurality of electrode end portions 17, the electrode end portion 17 formed in contact with the light emitting portion 13 whose interval in the column direction becomes gradually narrower is the other in the column direction than the central portion in the column direction of each light emitting portion 13. Formed closer.

  As a result, light can be emitted from the portion of the light emitting unit 13 closer to the column direction than the case where the electrode end portion 17 is provided at the column direction center of each light emitting unit 13. Therefore, as compared with the case where the light emitting units 13 are arranged at equal intervals in the column direction, the light emitted from the light emitting unit 13 is directed to the other in the column direction because the light emitting unit 13 is positioned in the other column direction. The bias can be suppressed. Thereby, the light intensity distribution at one end in the column direction of the light emitting element array 11 can be made uniform.

  In the first embodiment, the other part of the plurality of light emitting units 13 included in the light emitting element array 11 gradually decreases in the column direction as it goes to the other in the column direction. Specifically, the light emitting element array 11 is formed in plane symmetry with respect to a plane that passes through the center position in the column direction of the light emitting element array 11 and is perpendicular to the column direction. As a result, the light emitting element array 11 can achieve the same effect as the one end in the column direction also at the other end in the column direction.

  According to the first embodiment, the image forming apparatus 15 includes the light emitting element array 11. In the light emitting element array 11, the distance in the column direction between the one end and the other end of the substrate 12 in the column direction and the light emitting unit 13 positioned most in the column direction can be increased. On the other hand, the influence which the impurity which penetrate | invaded from the row direction one side and the other end surface has on the light emission part 13 can be made small. Therefore, it is possible to prevent the light intensity from the light emitting units 13 located at one side and the other side in the column direction from decreasing. Thereby, it is possible to suppress the formation of the image forming apparatus 15 in which the accuracy of the image is lowered at one end and the other end in the column direction of the light emitting element array 11.

  Moreover, since the yield concerning manufacture of the light emitting element array 11 can be made high, the manufacturing cost concerning the image forming apparatus 15 can be reduced. Further, even if the resolution is reduced, it is possible to prevent adverse effects on the light emitting units 13 located in one and the other in the column direction, so that the light intensity from the light emitting units 13 located in the one and the other in the column direction is reduced. It is possible to achieve both suppression of this and realization of the image forming apparatus 15 with high resolution.

  In addition, since the intensity of light emitted from the light emitting element array 11 can be prevented from changing suddenly with the change in the position in the column direction, the accuracy of image formation can be changed with the change in the position in the column direction. Can be prevented from changing suddenly. Further, the electrode end portions 17 formed in contact with the light emitting portions 13 whose intervals in the column direction are gradually narrowed are formed to be offset in the column direction from the central portion in the column direction of each light emitting portion 13. This suppresses the light emitted from the light emitting unit 13 from being biased to the other in the column direction, so that the light intensity distribution at one and the other ends in the column direction of the light emitting element array 11 can be made uniform. it can.

(Second Embodiment)
FIG. 5 is a plan view comparing the light emitting element array 11 according to the second embodiment of the present invention with the light emitting element array 11 according to the related art. In FIG. 5, the top view of the light emitting element array 11 when the light emitting element array 11 is arrange | positioned corresponding to the resolution of 1200 dpi is shown. The light emitting element array 11 according to the second embodiment includes a substrate 12 and a plurality of light emitting units 13. The light emitting units 13 are provided in a row on the substrate 12 and emit light when supplied with electric power. Moreover, as for some ones of the some light emission parts 13, the dimension of a column direction becomes small gradually as it goes to the column direction one side. In the second embodiment, the light emitting unit side electrode 14 has an electrode end 17, and the electrode end 17 is formed in contact with the light emitting unit 13.

  The electrode end portion 17 is formed to extend in a direction parallel to the substrate 12. The longitudinal direction of the electrode end portion 17 is set to be perpendicular to the thickness direction and the column direction of the substrate 12. The light emitting portion side electrode 14 includes a base portion 16 and an electrode end portion 17, and the base portion 16 and the electrode end portion 17 constitute a supply path when electric power is supplied to the light emitting portion 13. Each electrode end 17 is formed at the center of each light emitting unit 13 in the column direction. A potential difference between the light emitting unit side electrode 14 and the substrate 12, specifically, a potential difference between the electrode end 17 and the substrate 12 is applied to the light emitting unit 13.

  FIG. 6 is a cross-sectional view of the light emitting device 10 according to the second embodiment of the present invention. In the second embodiment, the light emitting unit 13 includes an n-type semiconductor layer 128, a p-type semiconductor layer 129, and an ohmic contact layer 25. The n-type semiconductor layer 128 is made of an n-type semiconductor, and is arranged in contact with the substrate 12 from one side in the thickness direction. The p-type semiconductor layer 129 is made of a p-type semiconductor, and is disposed in contact with the n-type semiconductor layer 128 from one side in the thickness direction. The ohmic contact layer 25 is arranged in contact with the p-type semiconductor layer 129 from one side in the thickness direction. The light emitting unit side electrode 14 is connected to the light emitting unit 13 from one side in the thickness direction than the light emitting unit 13. In the second embodiment, the light emitting unit 13 is a light emitting diode (abbreviated as “LED”).

  As shown in the lower part of FIG. 5, in the conventional technique, the dimensions in the column direction of the light emitting units 13 are all set to the same dimension, and are set to 9 μm when the resolution corresponds to 1200 dpi. In the second embodiment, as shown in the upper part of FIG. 5, the dimension in the column direction of some of the plurality of light emitting units 13 gradually decreases toward one side in the column direction. Another part of the plurality of light emitting units 13 is formed to have the same size regardless of the position in the column direction. Of the plurality of light emitting units 13, a region in the column direction where the light emitting unit 13 whose dimension in the column direction gradually decreases toward one side in the column direction is referred to as a “small light emitting unit region” 32. An area in which the dimension of the light emitting unit 13 in the column direction is the same regardless of the position in the column direction is referred to as a “steady dimension area” 33, and the dimension in the column direction of each light emitting unit 13 in the steady dimension area 33 is “steady state”. Referred to as “dimensions”.

  In the present embodiment, the small light emitting portion region 32 is set in a range from the light emitting portion 13 located closest to the column direction of the light emitting element array 11 to the center position in the column direction of the light emitting element array 11. In the second embodiment, in the light emitting element array 11 in which 60 light emitting units 13 are arranged in the column direction, the small light emitting unit region 32 is defined as a region in which the three light emitting units 13 on one side in the column direction are located most. A stationary dimension region 33 is formed at a position adjacent to the other side in the column direction with respect to the small light emitting portion region 32. In the small light emitting portion region 32, the distance between the cores of the light emitting elements 10 adjacent in the column direction is set to be the same, and is set to 21.15 μm when the resolution corresponds to 1200 dpi.

  For example, if the light emitting unit 13 is called the first light emitting unit and the second light emitting unit sequentially from one side in the column direction, and the small light emitting unit region 32 is set to a range including the first light emitting unit to the fifth light emitting unit, The six light emitting units are located in the steady dimension region 33 adjacent to the other side of the small light emitting unit region 32 in the column direction, and the dimension of the light emitting unit in the column direction is set to a regular dimension. In the present embodiment shown in FIG. 5, the stationary dimension is 9 μm. The dimension of the fifth light emitting unit in the column direction is set to 8 μm, for example, the dimension of the fourth light emitting unit in the column direction is set to 7 μm, the dimension of the third light emitting unit in the column direction is set to 6 μm, The dimension of the two light emitting units in the column direction is set to 5 μm, and the dimension of the first light emitting unit in the column direction is set to 4 μm.

  As a result, the distance between one end surface in the column direction of the substrate 12 and one end surface in the column direction of the first light emitting unit is 5.5 μm. If the light emitting elements 10 are arranged with all the regions where the plurality of light emitting elements 10 included in the light emitting element array 11 are arranged as the regular dimension region 33, one end face in the column direction of the substrate 12 and the column of the first light emitting units. Since the distance from one end surface in the direction is 3 μm, by forming the small light emitting portion region 32, the distance between one end surface in the column direction of the substrate 12 and one end surface in the column direction of the first light emitting portion is The distance can be greater than in the prior art.

  In the second embodiment, a part of the plurality of light emitting units 13 has a dimension in the column direction that gradually decreases toward one side in the column direction, and another part of the plurality of light emitting units 13 has a column direction. The dimension in the column direction gradually decreases toward the other side. The light emitting element array 11 is formed symmetrically with respect to a plane that passes through the center position in the column direction of the light emitting element array 11 and is perpendicular to the column direction.

  In the second embodiment, the light emitting elements 10 whose dimensions in the column direction gradually decrease toward one side in the column direction may be one half of the light emitting elements 10 arranged in the column direction. . Similarly, the light emitting elements 10 whose dimensions in the column direction gradually decrease toward the other in the column direction may be the light emitting elements 10 that are half of the light emitting elements 10 arranged in the column direction.

  When the steady dimension region 33 is formed, it is preferable that the light-emitting elements 10 whose dimensions in the column direction gradually decrease toward one side in the column direction are arranged at the most in the column direction among the light-emitting element arrays 11. As a result, the light emitting elements 10 included in the steady dimension region 33 can be arranged in the center of the light emitting element array 11 in the column direction, and uniform light emission can be performed in the center of the light emitting element array 11 in the column direction. It becomes possible.

  According to the second embodiment, a part of the plurality of light emitting units 13 included in the light emitting element array 11 is gradually reduced in dimension in the column direction toward one side in the column direction. Thereby, the space | interval of the row direction of the edge part of the row direction of the board | substrate 12 and the light emission part 13 most located in a row direction can be enlarged. Therefore, it is possible to prevent the light emitting unit 13 from being chipped when the substrate 12 is cut by dicing. In addition, by dicing, the influence of impurities entering the substrate 12 from one end face in the column direction on the light emitting portion 13 can be reduced. Therefore, the yield concerning manufacture of the light emitting element array 11 can be made high.

  If the interval in the column direction of the light emitting units 13 is constant, if the resolution is reduced, the column direction interval between the one end in the column direction of the substrate 12 and the light emitting unit 13 located at the most in the column direction is reduced. However, since the interval in the column direction of the light emitting units 13 changes gradually, the column direction interval between the one end portion in the column direction of the substrate 12 and the light emitting unit 13 located at the most in the column direction even if the resolution is reduced. Can be suppressed or prevented from becoming smaller.

  Therefore, it is possible to achieve both the prevention of the adverse effect on the light emitting unit 13 located at the most in the column direction and the reduction of the resolution. Moreover, since the dimension of the light emitting unit 13 in the column direction gradually changes as the position in the column direction changes, the intensity of light emitted from the light emitting element array 11 abruptly increases as the position in the column direction changes. It is possible to prevent the change.

  Moreover, according to 2nd Embodiment, the dimension of the column direction becomes small gradually as the other one part of the some light emission parts 13 goes to the column direction other side. Specifically, the light emitting element array 11 is formed in plane symmetry with respect to a plane that passes through the center position in the column direction of the light emitting element array 11 and is perpendicular to the column direction. As a result, the light emitting element array 11 can achieve the same effect as the one end in the column direction also at the other end in the column direction.

  Further, according to the second embodiment, since the image forming apparatus 15 includes the light emitting element array 11, similarly to the first embodiment, the light from the light emitting unit 13 located at one side and the other side in the most column direction. The intensity can be prevented from being reduced, and the formation of the image forming apparatus 15 in which the accuracy of the image is reduced at one end and the other end of the light emitting element array 11 can be suppressed. Further, since the maximum light emission intensity emitted from the light emitting element array can be increased, the amount of energy per unit time irradiated to the electrophotographic photosensitive member of the image forming apparatus can be increased. Therefore, the image forming speed can be increased.

  Further, even if the resolution is reduced, it is possible to prevent adverse effects on the light emitting units 13 located in one and the other in the column direction, so that the light intensity from the light emitting units 13 located in the one and the other in the column direction is reduced. And the realization of the image forming apparatus 15 having a high resolution can be achieved at the same time. In addition, it is possible to prevent the accuracy relating to image formation from changing suddenly due to a change in position in the column direction.

  Moreover, according to 2nd Embodiment, the dimension of the row direction of the light emission part 13 shall be 4 micrometers or more. Thereby, even if the dimension of the electrode end portion 17 in the column direction is 2 μm or more, it is possible to prevent the electrode end portion 17 from blocking the light emission from the light emitting portion 13. Can be made easier.

  FIG. 7 is a plan view of the light emitting element array 11 according to the third embodiment of the present invention. The light emitting element array 11 according to the third embodiment is similar to the light emitting element array 11 according to the second embodiment, and hereinafter, the description will focus on differences of the third embodiment from the second embodiment.

  In the third embodiment, the light emitting unit side electrode 14 is arranged in contact with the light emitting unit 13 from one side in the thickness direction. The light emitting portion side electrode 14 includes a base portion 16 and a separation portion 34, and the base portion 16 is disposed in contact with an end portion located on one side in the longitudinal direction of the light emitting portion 13. The separation portion 34 is formed in an elongated flat plate shape, and the thickness direction of the separation portion 34 is arranged to coincide with the thickness direction of the substrate 12. The dimension in the longitudinal direction of the separation portion 34 is 20 μm or less, and the other surface in the thickness direction of the separation portion 34 is in contact with the light emitting unit 13. Two separation portions 34 are provided in parallel in the width direction, and one longitudinal direction of the separation portion 34 continues to the base 16. The dimension in the width direction of the base portion 16 is set to a length equal to or greater than the distance between the spaced apart portions 34 that are separated in the width direction, and the base portion 16 and the spaced apart portion 34 form a U shape when viewed in the thickness direction.

  The light emitting unit side electrode 14 applies voltage to the light emitting unit 13 using the light emitting unit side electrode 14 as an anode and the back electrode 18 as a cathode. The current flux flowing through the light emitting portion 13 is generated between the base portion 16 and the separated portion 34 and the substrate 12, and the current flux is dispersed as compared with the case where one separated portion 34 is formed. In the cross section of the light emitting unit 13 perpendicular to the thickness direction, the area of the current flux is localized if one separated portion 34 is formed. In contrast, in the present embodiment, since the two spaced apart portions 34 are formed, the area of the current flux is formed wide. The light emitting unit 13 emits light in the thickness direction when a current flows in the thickness direction. Since the other side in the thickness direction of the light emitting unit 13 is in contact with the substrate 12, the light from the light emitting unit 13 is actually emitted toward one side in the thickness direction. The light from the light emitting part 13 is emitted from the remaining surface part of the one surface part in the thickness direction of the light emitting part 13 excluding the part in contact with the light emitting part side electrode 14.

  Assuming a virtual plane 126 perpendicular to the width direction by dividing the length of the side of 9 μm of the light emitting unit 13 into four equal parts in the width direction, three virtual planes 126 are set. When the central virtual plane among the three virtual planes 126 is referred to as a “central virtual plane” 127, the light emitting unit 13 and the light emitting unit side electrode 14 are formed symmetrically with respect to the central virtual plane 127. The two spaced-apart portions 34 are arranged at the positions of the virtual planes 126 on both sides of the three virtual planes 126, and the planes that bisect each separated portion 34 in the width direction are located on both sides of the three virtual planes 126. It coincides with the virtual plane 126.

  In the third embodiment, a part of the plurality of light emitting units 13 has a dimension in the column direction that gradually decreases toward one side in the column direction, and another part of the plurality of light emitting units 13 has a column direction. The dimension in the column direction gradually decreases toward the other side. The light emitting element array 11 is formed symmetrically with respect to a plane that passes through the center position in the column direction of the light emitting element array 11 and is perpendicular to the column direction.

  Further, according to the third embodiment, the light emitting element array 11 further includes the light emitting unit side electrode 14, and the light emitting unit side electrode 14 has the separated portion 34. The separation portion 34 is formed in contact with the plurality of light emitting units 13 whose dimensions in the column direction gradually decrease as going in one column direction. Further, the separation portion 34 is formed so as to be separated from each other across the central portion of the surface of the light emitting portion 13 on the side opposite to the substrate 12.

  Accordingly, it is possible to suppress the current flux generated in the light emitting unit 13 from being localized in the light emitting unit 13. Therefore, compared with the case where the current flux is localized, the amount of current generated in the light emitting unit 13 can be increased. Further, it is possible to increase the light intensity when the intensity of the light emitted from the light emitting unit 13 is saturated as the current increases. Thereby, the maximum light emission intensity of the light emitting unit 13 can be increased. Therefore, it is possible to increase the intensity of light emitted from the light emitting unit 13 as compared with the case where the light emitting unit side electrode 14 does not include the separation portion 34.

  Thereby, the dimension of the light emitting unit 13 in the column direction becomes smaller as it goes in the column direction, thereby preventing the intensity of light emitted from the light emitting unit 13 from becoming smaller in the column direction. it can. Therefore, the light intensity distribution at one end in the column direction of the light emitting element array 11 can be made uniform.

  Further, since the intensity of the light emitted from the light emitting unit 13 can be prevented from decreasing toward the one and the other in the column direction by decreasing toward the one and the other in the column direction, An image forming apparatus 15 having a uniform light intensity distribution at one end and the other end in the column direction can be realized.

  Each embodiment described above is illustrated in order to embody the technology according to the present invention, and does not limit the technical scope of the present invention. In addition to the combination of parts specifically described in each embodiment, the embodiments may be partially combined as long as the combination is not particularly troublesome. Furthermore, the technical contents according to the present invention can be variously modified within the technical scope described in the claims. A modification is shown below.

(Modification)
In the first embodiment, the dense region 27 includes one of the light emitting elements 10 in the column direction included in the light emitting element array 11. In the present invention, the dense region 27 is the center of the light emitting element array 11 in the column direction. As long as it is formed on one side in the column direction. For example, among a plurality of light emitting elements included in a light emitting element array, a regular distance region is formed in one row direction including some light emitting elements, and a dense region is formed on the other side in the column direction from the steady distance region. The steady distance region may be formed between the dense region and the center position in the column direction of the light emitting element array. The same configuration can be applied to other dense regions on the other side in the row direction.

  In the second embodiment, the small light emitting section region 32 includes the light emitting element 10 in the most column direction included in the light emitting element array 11. However, in the present invention, the small light emitting section region 32 is a column of the light emitting element array 11. What is necessary is just to be formed in the row direction one side from the center of a direction. For example, among a plurality of light emitting elements included in a light emitting element array, a regular dimension region is formed on one side in the column direction, including several light emitting elements, and small light emission is formed on the other side in the column direction from the regular dimension region. A partial region may be formed, and a stationary dimension region may be formed between the small light emitting unit region and the center position in the column direction of the light emitting element array. The same configuration can be applied to other dense regions on the other side in the row direction.

  In the first embodiment, the dimensions of the light emitting units 13 in the column direction are the same, and in the small light emitting unit region 32 of the second embodiment, the distance between the cores of the light emitting elements 10 adjacent to each other in the column direction. Are set to be the same, but a dense region similar to that in the first embodiment is formed, and in the dense region, the dimension in the column direction of the light emitting units is one in the column direction as in the second embodiment. Or it is also possible to make it the structure which becomes small as it goes to the other.

  In the first and second embodiments, although the light emitter is manufactured through a process of etching and etching, the light emitter is ion-implanted to obtain a predetermined concentration of impurities, thereby forming a PN junction. Can also be produced.

It is the top view which compared the light emitting element array 11 which concerns on 1st Embodiment of this invention with the light emitting element array 11 which concerns on a prior art. It is a top view of the light emission part 13 arrange | positioned in the comparative example similar to a prior art. It is sectional drawing of the light emitting element array 11 which concerns on 1st Embodiment of this invention. 1 is a side view illustrating a configuration of an image forming apparatus 15 according to a first embodiment of the present invention. It is the top view which compared the light emitting element array 11 which concerns on 2nd Embodiment of this invention with the light emitting element array 11 which concerns on a prior art. It is sectional drawing of the light emitting element 10 which concerns on 2nd Embodiment of this invention. It is a top view of the light emitting element array 11 in 3rd Embodiment of this invention. It is sectional drawing of the diode array chip based on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Light emitting element 11 Light emitting element array 12 Substrate 13 Light emitting part 14 Light emitting part side electrode 15 Image forming apparatus 16 Base 34 Separating part 90 Photosensitive drum 91 Developer supply means 92 Transfer belt 93 Cleaner 94 Charger 95 Fixing means 96 Control means

Claims (5)

A substrate,
A plurality of light emitting units that are provided in a row on the substrate and emit light when electric power is supplied, wherein a part of the plurality of light emitting units is arranged in a column direction toward one side in the column direction. A light-emitting element array including a plurality of light-emitting portions whose intervals are gradually narrowed. A substrate,
A plurality of light emitting units that are provided in a row on the substrate and emit light when electric power is supplied, wherein a part of the plurality of light emitting units is arranged in a column direction toward one side in the column direction. A light-emitting element array including a plurality of light-emitting portions that gradually become smaller in size. A light emitting unit side electrode connected to a surface of the light emitting unit opposite to the substrate and forming a supply path for supplying power to the light emitting unit;
Having an electrode end formed in contact with the light emitting portion;
The electrode end portion formed in contact with the light emitting portion whose interval in the column direction is gradually narrowed is a light emitting portion side electrode formed closer to the other side in the column direction than the central portion in the column direction of each light emitting portion. The light emitting device array according to claim 1, further comprising: A light emitting unit side electrode connected to a surface of the light emitting unit opposite to the substrate and forming a supply path for supplying power to the light emitting unit;
The light emitting unit side electrode further including a spaced-apart portion formed in contact with the light-emitting unit, the dimension of which in the column direction is gradually reduced, and spaced apart from each other with the central portion of the surface interposed therebetween. The light-emitting element array described in 1. The light emitting element array according to any one of claims 1 to 4,
An electrophotographic photosensitive member to which light emitted from the light emitting element array is irradiated;
Development supply means for supplying a developer to the electrophotographic photoreceptor;
Transfer means for transferring an image formed by a developer on the electrophotographic photoreceptor to a recording sheet;
An image forming apparatus comprising fixing means for fixing the developer transferred to the recording sheet.

Images