JP6817828B2 - An exposure device, an LED head, and an image forming device equipped with the exposure device. - Google Patents

Description

The present invention relates to an exposure apparatus and an LED head in which a substrate on which a light emitting element is mounted and a lens that collects light from the light emitting element are supported by a holder, and an image forming apparatus including the exposure apparatus and the LED head.

An LED (Light Emitting Diode) head used in a conventional printer or the like is assembled by pressing both end portions of a substrate on which a plurality of LED array chips are mounted against a contact surface provided on a holder (for example, Patent Document). See 1.).

Japanese Unexamined Patent Publication No. 2009-73041 (paragraphs 0022, 0033, 0040, FIG. 1)

However, in the above-mentioned conventional LED head, it is necessary to secure a space for bringing the substrate into contact with the holder, and the width of the substrate becomes large. Therefore, the number of substrates that can be cut out from one work board (referred to as the number of substrates to be taken). There is a problem that.) Is reduced.
An object of the present invention is to solve the above problems.

In order to solve the above problems, the present invention comprises a substrate on which a plurality of light emitting elements are mounted in the arrangement direction, a lens that collects light from the light emitting elements and extends in the arrangement direction, and the above. A substrate and a holder for supporting the lens are provided, the holder is arranged in the arrangement direction, has a plurality of contact portions that abut on the substrate, and the substrate is orthogonal to the arrangement direction. It has a convex portion protruding in the width direction from one end in the width direction, and a concave portion formed by notching a position corresponding to the convex portion on the other end opposite to the one end in the width direction. It is characterized in that the convex portion is brought into contact with the contact portion of the holder and the substrate is arranged in the holder.

As a result, the present invention has the effect that the number of substrates that can be cut out from one work board can be increased.

Explanatory drawing which shows the printer of Example 1. Explanatory drawing which shows LED head of Example 1. Explanatory drawing which shows the substrate of Example 1. Explanatory drawing which shows the assembly method of the substrate of Example 1. Explanatory drawing which shows other mode of contact part of Example 1. Explanatory drawing which shows the substrate of Example 2. Explanatory drawing which shows the assembly method of the substrate of Example 2.

Hereinafter, examples of the exposure apparatus, the LED head, and the image forming apparatus according to the present invention will be described with reference to the drawings.

Hereinafter, the LED head and the printer of this embodiment will be described with reference to FIGS. 1 to 5.

The printer 1 as the image forming apparatus of this embodiment is an electrophotographic printer, and has a function of printing an image based on the input print data on printing paper as a medium. It has the configuration shown in FIG.

The printer 1 is provided with a paper transport path 2 that connects the upper surface and the lower portion of the apparatus housing in a substantially S shape, and serves as a medium accommodating portion for accommodating paper at one end on the lower side of the paper transport path 2. A paper cassette 3 is provided, and a stacker 4 for accumulating printed paper is provided at the other end.
A hopping roller 5 for feeding each sheet of paper from the paper feed cassette 3 to the paper transport path 2 is provided at the connection portion between the paper transport path 2 and the paper transport cassette 3, and the paper transport direction of the paper transport path 2 ( A resist roller 6 for correcting skew or the like of the conveyed paper is arranged on the downstream side (see the arrow shown in FIG. 1).

On the downstream side of the resist roller 6, a transport belt 7, a fixing device 8, and a discharge roller 9 are arranged in this order along the paper transport direction.
The fuser 8 includes a heating roller 8a, a backup roller 8b, and the like, and fixes a toner image as a developer image on paper by pressure and heat.

In the printer 1 of this embodiment, four independent image forming units 11k, 11y, 11m, and 11c are arranged in the order of developing a toner image along the paper transport direction, and these four image forming units 11 are respectively arranged. Since the configuration is the same except for the set set colors, that is, K color (black), Y color (yellow), M color (magenta), and C color (cyan), one image forming unit 11 will be described below. To do.

The image forming unit 11 uniformly and uniformly charges the photoconductor drum 12 as an image carrier and the photoconductor drum 12 on which an electrostatic latent image is formed, and the charging roller 13 and the photoconductor drum 12 as charging means. A developing roller 14 as a developing agent carrier, a supply roller 15, and a set color, which adhere a toner as a developing agent to an electrostatic latent image formed on the outer peripheral surface of the developing agent to form a visible toner image. It is composed of a toner cartridge 16 or the like as a developer container containing toner.

The supply roller 15 as the developer supply member presses the outer peripheral surface of the developing roller 14, and supplies the toner supplied from the toner cartridge 16 to the developing roller 14.
The developing blade 17 as a developer layer regulating member presses the outer peripheral surface of the developing roller 14, and thins the toner supplied from the supply roller 15 onto the developing roller 14.

The cleaning blade 18 as a cleaning member presses the outer peripheral surface of the photoconductor drum 12 and scrapes off the toner remaining on the photoconductor drum 12 after transfer.
The transfer roller 19 as a transfer device is arranged to face the opposite side of the photoconductor drum 12 of each image forming unit 11 with the transport belt 7 sandwiched between them, and charges the paper in the opposite polarity to the toner on the surface of the photoconductor drum 12. The formed toner image is transferred onto the paper.

The LED head 20 as an exposure device is arranged above the photoconductor drum 12 of each image forming unit 11, exposes the photoconductor drum 12 according to the image data of each set color, and electrostatically lurks on the photoconductor drum 12. Form an image.

The printing operation by the printer 1 of this embodiment will be described below.

Upon receiving print data from a higher-level device such as a personal computer (not shown), the printer 1 starts a printing operation, feeds the paper in the paper cassette 3 to the paper transport path 2 by the hopping roller 5, and feeds the fed paper to the registration roller 6. Transport to.

The paper conveyed to the resist roller 6 is conveyed from the resist roller 6 to the transfer belt 7, and passes through the image forming units 11k, 11y, 11m, and 11c in order as the transfer belt 7 rotates in the paper transfer direction.
At this time, in each image forming unit 11, the surface of the photoconductor drum 12 is uniformly charged by the charging roller 13, and the charged surface is exposed by the LED head 20 that emits light according to the image data, and an electrostatic latent image is produced. It is formed.

Toner thinned by the developing blade 17 is electrostatically adhered to the electrostatic latent image on the developing roller 14, and a toner image of each set color is formed.
The formed toner images of the set colors are transferred to the paper by the transfer roller 19, and the color toner images are formed on the paper.
The toner remaining on the photoconductor drum 12 after the transfer is removed by the cleaning blade 18.

On the other hand, the paper on which the color toner image is transferred is conveyed to the fixing device 8, the toner image is fixed on the paper by the fixing device 8, and the color image is printed on the paper.
The printed paper on which the color image is printed is sandwiched between the ejection rollers 9 and ejected onto the stacker 4.

In this way, the printing operation by the printer 1 of this embodiment is performed.

As shown in FIG. 2, the LED head 20 mounted on each image forming unit 11 of the printer 1 described above includes an LED array chip 21 as a light emitting element and a drive IC for driving the LED array chip 21 composed of a plurality of LED chips arranged side by side. From the substrate 22 on which the above is mounted, the lens 23 such as the SELFOC lens array (SELFOC is a registered trademark of Nippon Plate Glass Co., Ltd.) that collects the light from the LED array chip 21, the mounting plate 24, the holder 25 that supports them, and the like It is composed.
Note that FIG. 2 is a perspective view having a cross section along the ZZ cross section shown in FIG. 4 (b).

The LED array chip 21 is mounted on the central portion of the substrate 22 along a direction orthogonal to the paper transport direction (referred to as an arrangement direction) (see FIG. 3), and each LED chip constituting the LED array chip 21 receives image data. It emits light according to the image data signal formed on the basis.

A plurality of bonding pads 26 are arranged on one side of the substrate 22 in the direction orthogonal to the arrangement direction (width direction), and the bonding pads 26 are attached to a connector 26a (see FIG. 5) to which a flexible flat cable (not shown) is mounted. ) Is connected to the LED array chip 21 with a wire 26b for transmitting an image data signal or the like.

The lens 23 is attached along the arrangement direction below the LED array chip 21 in the central portion of the lower part of the holder 25 by an adhesive portion 27 made of a silicone resin, an epoxy adhesive, an acrylic adhesive, or the like.
The mounting plate 24 is attached to the side plates on both sides of the holder 25 by a joining portion 28 made of a joining agent such as a silicone resin, an epoxy adhesive, or an acrylic adhesive.
Further, the mounting plate 24 is provided with a cable insertion hole (not shown) for connecting the flexible flat cable to the connector 26a on the board 22.

The holder 25 of this embodiment is provided with a plurality of support portions 29 formed by bending a part of the side plates on both sides inward, and an ultraviolet curable resin and an epoxy adhesive are provided on the support portions 29. , A columnar contact portion 31 formed of an acrylic adhesive or the like is provided.
The height of the contact surface of the contact portion 31 with the substrate 22 is determined so that the distance between the lens 23 and the LED array chip 21 becomes the optimum focal value peculiar to the lens 23.

FIG. 3 is a diagram showing a state when a substrate 22 for mounting an LED head on which an LED array chip 21 or the like is mounted is cut out from a work board, and FIG. 3A shows a state in which two conventional boards 22 are cut out. (B) shows the cut-out state of the two substrates 22 of this embodiment.
In the conventional substrate 22, as shown in FIG. 3A, a plurality of LED array chips 21 are arranged along the arrangement direction on the center line located at a distance A from the side ends on both sides in the width direction, and one of them. A plurality of bonding pads 26 are arranged along the arrangement direction on the side of the above.

Further, at the side ends on both sides of the substrate 22, a contact area 22a (referring to an area having a width B shown by a two-dot chain line in FIG. 3) for contacting the contact portion 31 of the holder 25 is provided. It is secured.
This is because the wire 26b is connected to the bonding pad 26 of the substrate 22 (see FIG. 2), so that a dedicated area may be provided in order to directly contact the substrate 22 with the contact portion 31 of the holder 25. Because it is necessary.

Further, the LED array chip 21 is arranged at the center of the substrate 22 in the width direction in order to suppress bending in the width direction due to heat generation when the LED chip emits light.
Therefore, in the conventional substrate 22, there is an electrically unnecessary region on the side opposite to the bonding pad 26.
The length of the conventional substrate 22 of this embodiment in the width direction is about 7 to 8 mm.

Such a conventional substrate 22 for mounting an LED head is formed by moving a router having a predetermined diameter in the arrangement direction and cutting the router with a cutting width C.
This cutting width C is formed as a result of moving the same router a plurality of times along the same route while changing the position in the width direction.

On the other hand, in the substrate 22 of this embodiment, as shown in FIG. 3B, the LED array chip 21 and the bonding pad 26 are arranged in the same manner as in the conventional case, and the width B is applied to one side end of the substrate 22. In order to secure the contact area 22a, a convex portion 33 projecting from one end of the substrate 22 in the width direction is provided.

Further, a recess 34 is formed in which the substrate 22 is cut out in the width direction from the other end at a position corresponding to the convex portion 33 at the other side end of the substrate 22, and the other end excluding the recess 34 is in contact with the width B. It is used as an area 22a.

In FIG. 3B, one convex portion 33 and one concave portion 34 are shown, but in reality, a plurality of convex portions 33 and concave portions 34 are provided along the arrangement direction, and the contact area 22a between the concave portions 34 is arranged in the arrangement direction. Is longer than the length of the convex portions 33 in the arrangement direction.

The LED array chip 21 of this embodiment is arranged on a center line in which the distance D ₁ from one side end and the distance D ₂ from the other side end are set to be the same in order to suppress bending in the width direction. LED.
In the setting of this distance D _1, the distance from one side end to the end of the bonding pad 26 is set as E so that the router does not interfere with the bonding pad 26 when the substrate 22 is cut (E is 100 μm in this embodiment). that's all).

In the substrate 22 for mounting the LED head of this embodiment, after moving the router having the same diameter as the conventional one in the arrangement direction, the protrusion 33 is once moved by the width B in the width direction to move in the arrangement direction. After being moved, it is returned by the width B in the width direction, moved again in the arrangement direction, and cut with the same cutting width C as the conventional one.

As a result, the convex portion 33 is formed at one end in the width direction of the substrate of this embodiment, and the concave portion 34 is simultaneously formed at a position corresponding to the convex portion 33 at the other end.
Further, the length of the openings of the concave portions 34 in the arrangement direction is 2C longer than the length of the tip of the convex portion 33, and the distance between the tip of the convex portion 33 and the bottom of the concave portion 34 is C, which is the same as the cutting width.

In this embodiment, when cutting with the same cutting width C using the same router as before, if the distance between the two boards 22 is widened, the distance and time for cutting with the router will be long, and the boards will be cut. If the distance between the 22 is narrowed, a router with a smaller diameter than before will be used, and the frequency of router replacement will increase, or the number of work boards to be stacked at the time of cutting will decrease, and the cost of board production will increase. Because it does.

As described above, in the substrate 22 of the present embodiment, the distance from the tip of the convex portion 33 to the center line of the LED array chip 21 is A, and the distance from the center line to both ends of the substrate 22 in the width direction is the same D. _{Since 1} and D ₂ , even if a contact area 22a having a width B is secured at the other end, the distance from the tip of the convex portion 33 to the other end is the length corresponding to the width B of the contact area 22a. It becomes shorter, and the width of the substrate 22 required for producing one substrate can be reduced.

The substrate 22 of the present embodiment as described above is mounted in the holder 25 shown in FIG. 4A, which is manufactured as the width of the substrate 22 is reduced.
Note that FIG. 4A is a top view showing a state in which the lens 23 is adhered to the holder 25 by the adhesive portion 27.

In the holder 25, the support portions 29 provided on the side plates on both sides and the contact portions 31 above the support portions 29 are staggered along the arrangement direction, that is, the contact portions 31 do not face each other in the width direction and are recessed. It is arranged at a position that does not overlap with the formation position of 34.

When the substrate 22 is arranged in such a holder 25, as shown in FIG. 4B, the convex portion 33 provided at one end of the substrate 22 in the width direction is brought into contact with the convex portion 33 provided at a position facing the convex portion 33. The contact area 22a at the other end is placed on the contact area 31 which is placed on the contact surface of the portion 31 and is provided at a position avoiding the recess 34 at the other end, and the substrate 22 is mounted on the mounting plate 24. A joint portion 28 is formed and fixed at both corners of the presser foot and the mounting plate 24 and the side plate of the holder 25 with a bonding agent.
The arrangement of the contact portion 31 in the vicinity of the mounting area of the connector 26a on the substrate 22 may be in the manner shown in FIGS. 5A and 5B.

That is, since a load is applied to the connector 26a due to the insertion and removal of the flexible flat cable, at least one convex portion 33 and an abutting portion 31 to be brought into contact with the convex portion 33 are provided at the central portion of the board 22 in the arrangement direction of the connector 26a mounting region. In the contact area 22a on the opposite side in the width direction, two contact portions 31 for contacting the contact area 22a are provided.
In this case, the arrangement of the abutting portions 31 is such that the two abutting portions 31 on the opposite sides are provided at the positions where the isosceles triangle with the abutting portion 31 abutting the convex portion 33 as the apex is formed. Good.

As described above, in the present embodiment, the contact area 22a for contacting the contact portion 31 of the holder 25 is a convex portion 33 protruding from one end of the substrate 22, and the LED array chip 21 is the substrate 22. Since it is arranged in the central portion in the width direction of the LED array chip 21, the width of the substrate 22 can be narrowed while suppressing the bending of the substrate 22 due to the heat generation of the LED array chip 21, and the substrate 22 can be cut out from one work board. The number can be increased.

As a result, the unit price per substrate can be reduced, the size of the LED head 20 can be reduced, and the cost of components such as the mounting plate 24 constituting the LED head can be reduced. ..

The LED head of this embodiment will be described below with reference to FIGS. 6 to 7. The same parts as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 6 is a diagram showing a state when a substrate 22 for mounting an LED head on which an LED array chip 21 or the like is mounted is cut out from a work board, and FIG. 6A shows a state in which two conventional boards 22 are cut out. (B) shows the cut-out state of the two substrates 22 of this embodiment.
Since the configuration of the conventional substrate 22 shown in FIG. 6A is the same as that of the first embodiment, the description thereof will be omitted.

As shown in FIG. 6B, the substrate 22 of this embodiment has the LED array chip 21 and the bonding pad 26 arranged in the same manner as in the conventional case, and the substrate 22 is located on one side end of the substrate 22 in the same manner as in the first embodiment. Is provided with a convex portion 33 (hereinafter, referred to as a first convex portion 33) for securing a contact area 22a having a width B.

At a position avoiding the position of the first convex portion 33 on the other side end of the substrate 22, it protrudes in the width direction from the other end of the substrate 22 in order to secure a contact area 22a having a width B of the other end portion. A second convex portion 41 is provided so that the first convex portion 33 and the second convex portion 41 do not face each other in the width direction.

Similar to the first embodiment, the LED array chip 21 of this embodiment is arranged on a center line having the same distances D ₁ and D ₂ from the side ends on both sides in order to suppress bending in the width direction. LED.
The distance E for setting the distance D ₁ is the same as that in the first embodiment.

In the substrate 22 for mounting the LED head of this embodiment, after moving the router having the same diameter as the conventional one in the arrangement direction, the substrate 22 is once moved in the width direction by the width B at the portion of the first convex portion 33. After moving in the arrangement direction, it is moved back in the width direction by the width B and moved in the arrangement direction again, and when the router is returned, it is once moved in the width direction by the width B at the second convex portion 41 and then moved in the arrangement direction. After moving, it is returned by the width B in the width direction, moved again in the arrangement direction, and cut with the same cutting width C as the conventional one.

As a result, the first convex portion 33 is formed at one end in the width direction of the substrate of the present embodiment, and the nested second convex portion 41 is simultaneously formed at a position avoiding the first convex portion 33 at the other end. Will be done.

As described above, in the substrate 22 of the present embodiment, the distance from the tip of each of the first convex portion 33 and the second convex portion 41 to the center line of the LED array chip 21 is A, and the distance from the center line to the substrate is A. The distances to both ends of 22 in the width direction are the same D ₁ and D ₂ . That is, the distance between the side ends on both sides of the substrate 22 and the inner surface of the side plate of the holder 25 facing the side ends is substantially the same.

Therefore, the distance between the tips of the first convex portion 33 and the second convex portion 41 is 2A as in the conventional case, but the first convex portion 33 and the second convex portion 41 are nested. Since it is formed in the state, the distance F between one side end of the first substrate 22 and the other side end of the second substrate 22 is the width B of the contact area 22a and the cutting width C. It becomes shorter by the difference between the two, and the number of boards 22 that can be cut out from one work board can be increased.

The substrate 22 of this embodiment as described above is mounted in the conventional holder 25 shown in FIG. 7A.

Similar to the first embodiment, the holder 25 has the support portions 29 provided on the side plates on both sides and the contact portions 31 on the support portions 31 in a staggered manner along the arrangement direction, that is, the contact portions 31 have widths. They are arranged at positions that do not face each other in the direction and overlap with the formation positions of the first convex portion 33 and the second convex portion 41.

When the substrate 22 is arranged in such a holder 25, as shown in FIG. 7B, a first convex portion 33 provided at one end of the substrate 22 in the width direction is provided at a position facing the first convex portion 33. It is placed on the contact surface of the contact portion 31, and the second convex portion 41 at the other end is placed on the contact portion 31 provided at a position facing the contact portion 31, and the substrate 22 is mounted on the mounting plate 24. suppress.

Then, a bonding agent for forming the joint portion 28 is poured from the gaps on both sides between the side surfaces on both sides of the mounting plate 24 and the inner surface of the side plate of the holder 25 using a nozzle or the like, and the side surfaces on both sides of the substrate 22. The end and the inner surface of the side plate of the holder 25 are sealed with a bonding agent, and the bonding portions 28 are formed and fixed at the corners on both sides of the mounting plate 24 and the side plate of the holder 25.

As described above, in the present embodiment, the first convex portion 33 and the second convex portion 41 are nested to cut out the substrate 22 from the work board. Therefore, the first substrate 22 The distance F between one side end and the other side end of the second substrate 22 can be shortened by the difference between the width B of the contact area 22a and the cutting width C, and one substrate. It is possible to increase the number of substrates 22 that can be cut out from the work board of the above, and to ensure compatibility with the conventional substrate 22.

Further, when the substrate 22 is mounted in the holder 25, the distance between the side ends on both sides of the substrate 22 and the inner surface of the side plate of the holder 25 facing the substrate 22 is substantially the same, so that the amount of the bonding agent used for sealing is one end. Since the distances D ₁ and D ₂ between the LED array chip 21 and both side ends of the substrate 22 are the same on the side and the other end side, the amount of heat generated by the light emission of the LED array chip 21 is one end of the substrate 22. It is evenly discharged from the side and the other end side to the holder 25, the uniformity of the temperature distribution of the substrate 22 is enhanced, the bending of the LED array chip 21 at the time of light emission can be further suppressed, and the color deviation at the time of color printing can be prevented. It can be suppressed to prevent deterioration of print quality.

In the above embodiments, the position of providing the LED array chip 21 has been described the distance D _1, D ₂ from both sides of the side end as is on the center line of the substrate 22 which is the same, the distance D _1, D ₂ may be substantially the same. Specifically, if the distance D ₁ is within ± 10% of the distance D ₂ , the effect of suppressing the bending of the substrate 22 can be obtained.

Further, in each of the above embodiments, the contact portion 31 with which the substrate 22 abuts is formed by using an ultraviolet curable resin or the like on a support portion 29 formed by bending a part of the side plate of the holder 25 inward. However, when the holder 25 is formed by using a mold resin or the like, the contact portion 31 may be integrally molded, or may be formed by machined aluminum die casting.

Further, in each of the above embodiments, the medium has been described as printing paper, but the medium is not limited to the above, and may be OHP paper, envelopes, copying paper, special paper, or the like.

1 Printer 2 Paper transport path 3 Paper feed cassette 4 Stacker 5 Hopping roller 6 Resist roller 7 Conveyor belt 8 Fixer 9 Discharge roller 11, 11k, 11y, 11m, 11c Image forming unit 12 Photoreceptor drum 13 Charging roller 14 Development roller 15 Supply Roller 16 Toner Cartridge 17 Development Blade 18 Cleaning Blade 19 Transfer Roller 20 LED Head 21 LED Array Chip 22 Board 22a Contact Area 23 Lens 24 Mounting Plate 25 Holder 26 Bonding Pad 26a Connector 26b Wire 27 Bonding 28 Bonding 29 Support 31 Contact part 33 Convex part (first convex part)
34 concave part 41 second convex part

Claims (7)

A substrate with multiple light emitting elements mounted in the array direction,
A lens that collects light from the light emitting element and extends in the array direction,
The substrate and the holder for supporting the lens are provided.
The holder
It is arranged in the arrangement direction and has a plurality of contact portions that come into contact with the substrate.
The substrate is
A convex portion protruding in the width direction from one end in the width direction, which is orthogonal to the arrangement direction,
It has a concave portion formed by notching a position corresponding to the convex portion of the other end opposite to the one end in the width direction.
An exposure apparatus characterized in that the convex portion is brought into contact with the contact portion of the holder and the substrate is arranged in the holder. In the exposure apparatus according to claim 1,
The exposure device is characterized in that the light emitting element is arranged at a position where the distance from one end of the substrate and the distance from the other end of the substrate are substantially the same. In the exposure apparatus according to claim 1 or 2.
A contact area for contacting the contact portion is provided between the recesses.
An exposure apparatus characterized in that the length of the contact area in the arrangement direction is made longer than the length of the convex portion in the arrangement direction of the first convex portion. In the exposure apparatus according to any one of claims 1 to 3.
An exposure apparatus characterized in that a bonding pad is arranged along the arrangement direction between the light emitting element and the convex portion. A substrate with multiple light emitting elements mounted in the array direction,
A lens that collects light from the light emitting element and extends in the array direction,
The substrate and the holder for supporting the lens are provided.
The holder
It is arranged in the arrangement direction and has a plurality of contact portions that come into contact with the substrate.
The substrate is
A first convex portion protruding in the width direction from one end in the width direction which is orthogonal to the arrangement direction, and
The opposite end of the one end, provided at a position not opposed to the first convex portion in the width direction, and a second convex portion protruding from the other end of the substrate in the width direction,
An exposure apparatus characterized in that the first and second convex portions are brought into contact with the contact portion of the holder, and the substrate is arranged in the holder. A board with multiple LED array chips mounted in the array direction,
A lens that collects light from the light emitting element and extends in the array direction,
The substrate and the holder for supporting the lens are provided.
The holder
It is arranged in the arrangement direction and has a plurality of contact portions that come into contact with the substrate.
The substrate is
A convex portion protruding in the width direction from one end in the width direction, which is orthogonal to the arrangement direction,
It has a concave portion formed by notching a position corresponding to the convex portion of the other end opposite to the one end in the width direction.
An LED head characterized in that the convex portion is brought into contact with the contact portion of the holder and the substrate is arranged in the holder. An image forming apparatus comprising the exposure apparatus according to any one of claims 1 to 5 or the LED head according to claim 6.

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