JP2023025824A - Image formation device - Google Patents

Abstract

To solve such the problem that productivity decreases because the smaller a diameter of a nozzle through which a sealant passes is made to be, the smaller an amount of the sealant per unit time passes through the nozzle becomes, on the other hand, although a method for reducing viscosity of a sealant is known as a method for suppressing decrease in productivity, the higher the viscosity of the sealant, the better in order to improve reliability of sealing.SOLUTION: A first sealant is applied to an edge of a region for implementing a connector of an edge of a substrate while a second sealant having viscosity that is higher than that of the first sealant is applied to a region other than a region to which the first sealant is applied of the edge of the substrate.SELECTED DRAWING: Figure 8

Description

The present invention relates to an exposure head and an image forming apparatus having the exposure head.

2. Description of the Related Art Some image forming apparatuses such as printers and copiers use an exposure head having a plurality of light emitting elements for exposing a photoreceptor. Some exposure heads use LEDs (Light Emitting Diodes) and organic ELs (Electro Luminescence) as examples of light emitting elements. The exposure head has a substrate on which light-emitting elements are arranged and a holder that holds a lens array for condensing light emitted from the light-emitting elements onto a photoreceptor.

The holder described in Patent Document 1 has a U-shape. Specifically, a U-shape is formed by a base portion having an opening into which a lens array is inserted and fixed, and a pair of extension portions extending from the base portion in a direction away from the photoreceptor. are doing. The substrate is fixed to the inner walls of the pair of extensions with an adhesive. A gap between the edge of the substrate and the inner walls of the pair of extending portions is sealed with a sealant.

JP 2012-66499 A

A sealant for sealing the gap between the edge of the substrate and the pair of extensions is injected through a nozzle. However, the substrate is provided with a connector for connecting a flexible flat cable that transmits a signal for driving the light-emitting element, and depending on the thickness of the nozzle, the connector and the inner wall of the pair of extensions may differ. No nozzle can be inserted between them. Therefore, in order to insert the nozzle between the connector and the inner walls of the pair of extensions, it is necessary to make the diameter of the nozzle smaller than the width between the connector and the inner walls of the pair of extensions.

However, the smaller the diameter of the nozzle, the smaller the amount of sealant passing through the nozzle per unit time, resulting in lower productivity. As a method of suppressing the decrease in productivity, there is a method of lowering the viscosity of the sealant, but the higher the viscosity of the sealant, the better, in order to improve the certainty of sealing.

Accordingly, an object of the present invention is to improve the sealing performance of the gap between the substrate and the holder by varying the viscosity of the sealant in consideration of the location to be sealed.

An exposure head according to the present invention includes a substrate having a light emitting element that emits light for exposing a photoreceptor, a connector to which a flexible flat cable that transmits a signal for driving the light emitting element is connected, and a light emitting element. a lens array for condensing the emitted light onto the photosensitive member; and a holder for holding the substrate and the lens array, wherein the holder is a base having an opening into which the lens array is inserted. a pair of extensions extending from both ends of the base portion in the short direction of the holder in a direction away from the photoreceptor and to which edges of the substrate in the short direction are bonded; a first sealant that seals a gap between an edge of the mounting area of the connector and the pair of extending portions among edges of the board in the hand direction; and a viscosity higher than that of the first sealant. A second sealant that seals a gap between the pair of extensions and a region of the edge of the substrate in the lateral direction other than the region to which the first sealant is applied. and a second sealant.

Further, the image forming apparatus according to the present invention includes a photoreceptor, a light-emitting element that emits light for exposing the photoreceptor, and a connector to which a flexible flat cable that transmits a signal for driving the light-emitting element is connected. a lens array for condensing light emitted from the light emitting element onto the photoreceptor; and a holder for holding the substrate and the lens array,
The holder has a base portion formed with an opening into which the lens array is inserted, and both ends of the base portion in the lateral direction of the holder, extending in a direction away from the photoreceptor and extending in the lateral direction. a pair of extensions to which edges of the substrate are bonded; and a first sealing gap between the pair of extensions and the edge of the mounting area of the connector among the edges of the substrate in the lateral direction. a sealant and a second sealant having a viscosity higher than that of the first sealant, wherein the region of the edge of the substrate in the lateral direction coated with the first sealant and a second sealant that seals a gap between the region other than the pair of extensions and the pair of extensions.

Sealability of the gap between the substrate and the holder can be improved.

1 is a schematic cross-sectional view of an image forming apparatus; FIG. 1 is an overall view of an optical print head; FIG. FIG. 4 is a diagram for explaining the configuration of a substrate and a lens array; The figure for demonstrating the structure of a holder. FIG. 4 is a diagram for explaining a substrate; FIG. 4 is a diagram for explaining the positional relationship between the holder and the substrate; FIG. 4 is a diagram for explaining a sealant; FIG. 4 is a diagram for explaining a portion sealed with a sealant; FIG. 10 is a diagram for explaining another embodiment;

EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated with reference to drawings. It should be noted that the dimensions, materials, shapes, relative positions, etc. of the components described below are not intended to limit the scope of the present invention only to them, unless otherwise specified.

(Image forming device)
First, a schematic configuration of the image forming apparatus 1 will be described.

FIG. 1 is a schematic cross-sectional view of an image forming apparatus 1. FIG. The image forming apparatus 1 shown in FIG. 1 is a color printer (MFP: Multi Function Printer) equipped with a reading device, but the embodiment may be a copier without a reading device. Further, the embodiment is not limited to a so-called tandem type color image forming apparatus having a plurality of photosensitive drums 103 as shown in FIG. A forming device may be used.

The image forming apparatus 1 shown in FIG. 1 includes four image forming units 102Y, 102M, 102C, and 102K (hereinafter collectively simply referred to as “image forming units 102”) that form toner images of yellow, magenta, cyan, and black. ”). Further, the image forming units 102Y, 102M, 102C, and 102K respectively include photosensitive drums 103Y, 103M, 103C, and 103K (hereinafter collectively referred to simply as "photosensitive drums 103"). These photosensitive drums are arranged apart from each other. Further, the image forming units 102Y, 102M, 102C, and 102K include chargers 104Y, 104M, 104C, and 104K (hereinafter collectively referred to simply as "chargers 104") that charge the photosensitive drums 103Y, 103M, 103C, and 103K, respectively. ). The image forming units 102Y, 102M, 102C, and 102K include LED (Light Emitting Diode, hereinafter referred to as LED) exposure units 500Y and 500M as exposure light sources for emitting light for exposing the photosensitive drums 103Y, 103M, 103C, and 103K. , 500C, and 500K (hereinafter collectively referred to simply as “exposure unit 500”). The image forming apparatus 1 shown in FIG. 1 is an image forming apparatus of a so-called "lower surface exposure method" that exposes the photosensitive drum 103 from below. Furthermore, the image forming units 102Y, 102M, 102C, and 102K develop electrostatic latent images on the photosensitive drums 103 with toner, and developing units 106Y, 106M, 106C, and 106K that develop respective color toner images on the photosensitive drums 103. (Hereinafter, also collectively simply referred to as “developer 106”). The symbols Y, M, C, and K indicate colors of toner.

The image forming apparatus 1 includes an intermediate transfer belt 107 to which the toner image formed on the photosensitive drum 103 is transferred, and a primary transfer roller 108 (Y, M, C, K). The image forming apparatus 1 also includes a secondary transfer roller 109 that transfers the toner image on the intermediate transfer belt 107 onto the recording material S conveyed from the paper feeding unit 101, and a secondary transfer roller 109 that transfers the secondarily transferred image onto the recording material S. A fixing device 100 for fixing is provided.

Toner remains on the surfaces of the photosensitive drums 103Y, 103M, 103C, and 103K after the primary transfer. These residual toners are removed by drum cleaning devices 8Y, 8M, 8C, and 8K (hereinafter collectively referred to simply as “drum cleaning devices 8”) and collected in a collection toner container 5. FIG.

Also, toner remains on the surface of the intermediate transfer belt 107 after secondary transfer. This residual toner is removed by the belt cleaning device 7 and collected in the collection toner container 5 .

(Image forming process)
The exposure unit 500Y exposes the surface of the photosensitive drum 103Y charged by the charger 104Y. As a result, an electrostatic latent image is formed on the photosensitive drum 103Y. Next, the developing device 106Y develops the electrostatic latent image formed on the photosensitive drum 103Y with yellow toner. A yellow toner image developed on the surface of the photosensitive drum 103Y is transferred onto the intermediate transfer belt 107 by the primary transfer roller 108Y. Magenta, cyan, and black toner images are also transferred to the intermediate transfer belt 107 in a similar image forming process.

The toner image of each color transferred onto the intermediate transfer belt 107 is conveyed by the intermediate transfer belt 107 to the secondary transfer portion T2. A transfer bias for transferring the toner image onto the recording material S is applied to the secondary transfer roller 109 arranged in the secondary transfer portion T2. The toner image conveyed to the secondary transfer portion T2 is transferred onto the recording material S conveyed from the paper feed portion (paper feed cassette) 101 by the transfer bias of the secondary transfer roller 109 .

The recording materials S are stored in a stacking manner in the paper feeding unit 101, and are fed to the conveying path 20 in accordance with image forming timing. As for the paper feeding method, first, the leading edge of the recording material S is bounced up by the friction of the paper feeding roller 80, and the recording material S is separated by a pair of paper separation conveying rollers 9a and 9b for preventing the recording material S from being double-fed. Only one sheet is conveyed to the conveying path 20 . After that, the recording material S pulled out by the pair of transport rollers 10a and 10b is transported through the transport path 20 to the pair of registration rollers 11a and 11b, where it is temporarily stopped. After skew correction and timing correction are performed by the pair of registration rollers 11a and 11b, the sheet is conveyed to the secondary transfer portion T2. The recording material S onto which the toner image has been transferred at the secondary transfer portion T2 is conveyed to the fixing device 100. As shown in FIG. The fixing device 100 fixes the toner image on the recording material S using heat and pressure. The recording material S that has undergone fixing processing by the fixing device 100 is discharged to a paper discharging section 111 .

Further, as shown in FIG. 1, the image forming apparatus 1 includes toner containers 4Y, 4M, 4C, and 4K (hereinafter collectively referred to simply as "toner container 4"). By performing image formation, the amount of toner in the developing unit 641 (described later) decreases. At that time, the toner is supplied from toner containers 4Y, 4M, 4C, and 4K provided corresponding to the respective image forming units 102Y, 102M, 102C, and 102K to the developing unit 641 (described later) through pipes (not shown). supplied. That is, in the developing unit 641 (described later) included in the image forming apparatus 1 according to this embodiment, new toner is replenished from the toner container 4, and part of the excess toner is collected as residual toner in the collected toner container 5. transport to

(Basic configuration of optical print head)
Next, the optical print head 105 (exposure head) included in the exposure unit 500 will be described. Here, as an example of an exposure method employed in an electrophotographic image forming apparatus, laser beam scanning is performed in which a semiconductor laser irradiation beam is scanned by a rotating polygon mirror or the like and a photosensitive drum is exposed through an f-θ lens or the like. There is an exposure method. The “optical print head 105 ” described in this embodiment is used in an LED exposure method that exposes the photosensitive drum 103 using light emitting elements such as LEDs arranged along the rotation axis direction of the photosensitive drum 103 . Therefore, it cannot be used for the laser beam scanning exposure method mentioned above.

2, the optical printhead 105 comprises a holder 505 that holds a lens array 506 and a substrate 502 (not shown in FIG. 2). A pin 507 is provided on one end side of the holder 505 in the longitudinal direction of the holder 505 . Similarly, a pin 508 is provided on the other end side of the holder 505 . These pins 507 and 508 abut on a frame that rotatably supports the photoreceptor 103 to determine the distance between the photoreceptor 103 and the lens array 506 . The frame referred to here means a portion corresponding to a portion of the frame of the drum unit or a bush that rotatably supports the flange press-fitted to the photoreceptor 103 .

Next, the substrate 502 will be described. FIG. 3A is a schematic perspective view of the substrate 502. FIG. FIG. 3(b1) shows the arrangement of a plurality of LEDs 503 provided on the substrate 502 on the substrate 502. FIG. FIG. 3(b2) is an enlarged view of FIG. 3(b1).

An LED chip 639 is mounted on the substrate 502 . As shown in FIG. 3A, an LED chip 639 is provided on one side of the substrate 502, and a long connector is provided on the other side (the side opposite to the side where the light emitting elements are arranged). 504 is provided. The connector 504 is attached to the lower surface of the substrate 502 so that its longitudinal direction is along the longitudinal direction of the substrate 502 . Wiring for supplying signals to each LED chip 639 is provided on the substrate 502 . One end of a flexible flat cable (FFC) (not shown) is connected to the connector 504 . The FFC transmits signals for driving the light emitting elements.

A main body of the image forming apparatus 1 is provided with a substrate having a control section and a connector. The other end of FFC 160 is connected to the connector. That is, the FFC 160 electrically connects the controller and the substrate 502 . A drive signal is input to the substrate 502 via the FFC 160 and the connector 504 from the control unit of the main body of the image forming apparatus 1 . LED chip 639 is driven by a drive signal input to substrate 502 .

The LED chip 639 mounted on the substrate 502 will be described in more detail. As shown in FIGS. 3(b1) and 3(b2), a plurality of LED chips 639-1 to 639-29 (29 ) are arranged. Each of the LED chips 639-1 to 639-29 has 516 LEDs 503 arranged in a line in its longitudinal direction. A center-to-center distance k2 between adjacent LEDs 503 in the longitudinal direction of the LED chip 639 corresponds to the resolution of the image forming apparatus 1 . Since the image forming apparatus 1 of this embodiment has a resolution of 1200 dpi, the LED chips 639-1 to 639-29 are aligned in the longitudinal direction so that the distance between the centers of adjacent LEDs 503 is 21.16 μm. are arranged in Therefore, the exposure range of the optical print head 105 of this embodiment is approximately 314 mm. The photosensitive layer of the photosensitive drum 103 is formed with a width of 314 mm or more. Since the length of the long side of A4 size recording paper and the length of the short side of A3 size recording paper are 297 mm, the optical print head 105 of this embodiment can be used for both A4 size recording paper and A3 size recording paper. has an exposure range in which image formation is possible.

The LED chips 639-1 to 639-29 are alternately arranged in two rows along the rotation axis direction of the photosensitive drum 103. FIG. That is, as shown in FIG. 3(b1), odd-numbered LED chips 639-1, 639-3, . LED chips 639-2, 639-4, . By arranging the LED chips 639 in this way, as shown in FIG. The center-to-center distance k1 of the LEDs arranged at the other end of the LED chip 639 can be made equal to the center-to-center distance k2 of the adjacent LEDs 503 on one LED chip 639 . In this embodiment, the configuration using the LED 503 as the exposure light source is exemplified, but an organic EL (Organic Electro Luminescence) may be used as the exposure light source.

Next, the lens array 506 will be described. FIG. 3C1 is a schematic diagram of the lens array 506 viewed from the photosensitive drum 103 side. 3C2 is a schematic perspective view of the lens array 506. FIG. As shown in FIG. 3(c1), a plurality of lenses are arranged in two rows along the direction in which the plurality of LEDs 503 are arranged. The lenses are alternately arranged so that one of the lenses of the other row is arranged so as to be in contact with both adjacent lenses in the arrangement direction of the lenses of the other row. Each lens is a cylindrical glass rod lens. The material of the lens is not limited to glass, and may be plastic. The shape of the lens is not limited to a cylindrical shape, and may be a polygonal prism such as a hexagonal prism.

A dotted line Z shown in FIG. 3(c2) indicates the optical axis of the lens. The optical print head 105 can be moved in a direction (vertical direction) generally along the optical axis of the lens indicated by the dotted line Z by a moving mechanism (not shown). The optical axis of the lens referred to here means a line connecting the center of the light exit surface of the lens and the focal point of the lens. Radiation light emitted from the LED 503 enters a lens provided in the lens array 506 . The lens has a function of condensing incident radiation light on the surface of the photosensitive drum 103 . When assembling the optical print head 105, the lens array 506 is arranged so that the distance between the light emitting surface of the LED 503 and the light incident surface of the lens and the distance between the light emitting surface of the lens and the surface of the photosensitive drum 103 are substantially equal. , the mounting position with respect to the holder 505 is adjusted.

FIG. 4 is a diagram for explaining the holder 505. FIG. The holder 505 includes a base portion 5050B formed with an opening 5052 into which the lens array 506 is inserted, extension portions 5050R and 5050L extending from the left and right ends of the base portion 5050B in the direction away from the photosensitive drum 103. have The extending portion 5050R and the extending portion 5050L are portions corresponding to a pair of extending portions. The base portion 5050B and the extension portion 5050R (5050L) are integrated and form a U-shape. An opening 5053 is formed on the side opposite to the base portion 5050B by forming the holder 505 in a U-shape. The substrate 502 is inserted from the opening 5053, that is, the lower side of the U-shaped holding member 1505, and is adhered to the inside of the extension 5050R and the inside of the extension 5050L with an adhesive. Further, the lens array 506 is also adhered to the base portion 5050B with an adhesive while being inserted into the opening 5052 formed in the base portion 5050B.

By holding the substrate 502 and the lens array 506 by the holder 505 as described above, the LEDs 503 and the incident surface 506b of the lens array 506 face each other. Light emitted from the LED 503 is incident on the incident surface 506b and emitted toward the photosensitive drum 103 from the emitting surface 506a.

(Sealant)
FIG. 5(a) is a perspective view showing a substrate 502 on which an LED 503 is mounted. This figure is a perspective view from the direction in which the connector 504 is mounted, and the LED 503 is mounted on the other surface. A driver IC 900 for controlling light emission of the LED 503 is mounted on both ends of the connector 504 . To simplify the explanation, mounted parts such as other resistors and capacitors are not shown. The driver IC 900 used in this embodiment is an IC chip of 8 mm square and 0.85 mm thick, and a plurality of electrode pads on the back surface of the IC chip and electrodes on the substrate 502 are electrically connected by solder.

FIG. 5B is a diagram of the substrate 502 held by the holder 505. FIG. FIG. 6 is a cross-sectional perspective view when cut at the connector 504 in FIG.

The holder 505 in this embodiment is a thin plate made of metal with a thickness of about 1 mm, and is a component formed by pressing an electrogalvanized steel plate. As described above, the holder 505 has a front pin 507 and a rear pin 508 at both ends in the longitudinal direction, and is manufactured in a U-shape instead of a box shape with four sides bent.

The opening 5052 of the holder 505 is one size larger than the lens array 506, and the lens array 506 is fixed to the holder 505 with an adhesive. Also, the substrate 502 is formed one size smaller than the holder 505 , and the position of the substrate 502 is adjusted so that the optical axis of the LED 503 is aligned with the center of the lens array 506 . After that, it is fixed to the holder 505 with an adhesive between the wall surfaces 901 on both sides of the substrate 502 in the lateral direction of the holder 505 . This adhesive is, for example, an ultraviolet curable adhesive, which is cured by applying ultraviolet rays after being applied in a liquid or gel state to the bonding portion.

The lens array 506 and the substrate 502 are fixed to the holder 505 in a relatively short time by bonding at multiple points, and a gap remains even after bonding with the adhesive. Therefore, foreign matter such as toner can enter the space around the LEDs 503 and the lens array 506 of the holder 505 and the substrate 502, and problems such as a reduction in the amount of light may occur.

Therefore, as shown in FIG. 6, a sealant 513 is applied so that the clearance of the opening 5052 is in contact with both the lens array 506 and the holder 505 . In addition, a sealant 514 is applied to the gap between the edge of the substrate 502 and the extending portion 5050R (5050L) of the holder 505 in the lateral direction of the substrate 502 so as to be in contact with both. The sealant 513 , 514 solidifies over time and seals the substrate 502 and lens array 506 .

As for the method of applying the sealant, it is preferable to use a dispenser (nozzle) to control the amount of the liquid agent, and to use a nozzle/needle at the outlet of the liquid agent to precisely apply the sealant. In the actual sealing process, first, the nozzle is arranged near one end of the substrate 504 in the longitudinal direction of the substrate 504 . Injection of the sealant 514 is started while the tip of the nozzle is directed to the gap between the edge of the substrate 504 and the extending portion 5050R. The nozzle is then moved along the edge of the substrate 504 while extracting the encapsulant 514 . In this way, the gap between the edge of the substrate 504 and the extending portion 5050R is filled with the sealant 514 . A gap between the edge of the substrate 504 and the extending portion 5050L is also filled with the sealant 514 by the same procedure.

As the sealant 514b, silicon having appropriate flexibility is used. As an example, SE9189L (viscosity: 22 Pa·s), which is a one-liquid type RTV rubber of the Dow Toray Industries, Inc., is a room-temperature curing type. Due to the properties of silicon, it is relatively soft, deforms flexibly when filled, and can substantially seal gaps. As the outlet nozzle/needle, for example, SNA-12G (inner diameter 2.27 mm, outer diameter 2.77 mm) manufactured by Musashi Engineering Co., Ltd. is used, so that the shape when filled is good without flowing down like liquid. can be maintained. The viscosity of the sealant 514b can be measured with a viscometer, for example, MCR302 rheometer manufactured by Anton Paar.

FIG. 7A is a cross-sectional view of the holder 505 taken along a plane passing through the area of the substrate 502 where the connector 504 is mounted. As shown in FIG. 7, the gap G between the connector 504 and the extending portion 5050R (5050L) of the holder 505 is narrow, and the diameter of the nozzle/needle needs to be reduced in order to perform coating with the nozzle/needle.

Since the width of the connector 504 in the lateral direction is 4 mm, the distance between the extending portions 5050R and 5050L is 9 mm, and the connector 504 is arranged in the center between the wall surfaces 901, the connector 504 and the extending portion The gap G with 5050R (5050L) is 2.5 mm.

FIG. 7(b) shows the relationship between the nozzle 520, the wall surface 901, and the connector 504 in FIG. 7(a). Nozzle 520 has an outer diameter of 2.77 mm using the SNA-12G described above. Therefore, since the gap G (2.5 mm)<the nozzle 520 (2.77 mm), the nozzle 520 does not enter the gap G. That is, the sealant 514 cannot be applied.

In order to apply the sealant 514 to the gap G, it is necessary to reduce the diameter of the nozzle 520 . However, when the diameter of the nozzle 520 is reduced, the amount of the sealant 514b (second sealant) passing through the nozzle 520 per unit time is reduced, resulting in a decrease in productivity. In order for the sealant 514 to easily pass through the nozzle, the viscosity of the sealant 514 needs to be lowered. However, the sealant 514 with low viscosity may not provide sufficient sealing.

Therefore, in this embodiment, the sealant 514a having a lower viscosity than the sealant 514b is used. That is, as shown in FIG. 8, the feature of this embodiment is that two types of sealing agents having different viscosities are used. The sealant 514a (first sealant) in the vicinity of the connector 504 has a lower viscosity than the sealant 514b in the vicinity of the connector 504 . Specifically, the sealing agent 514a is applied to the edge corresponding to the mounting area where the connector 504 is mounted (on the substrate 504), among the edges of the substrate 504 in the lateral direction of the substrate 504, to provide sealing. Agent 514b is applied to the edges of substrate 504 that correspond to areas other than the mounting area where connector 504 is mounted (on substrate 504). The nozzle needs to be replaced in the middle of the sealing operation, and the time required for the replacement operation is the time required to coat the area corresponding to the mounting area of the connector 504 on the substrate 502 with the nozzle having an outer diameter of 2.77 mm. It's short compared to the time it takes. Therefore, the sealant 514b is applied to the portions where the gap is sufficiently secured, and the sealant 514a having a low viscosity is applied only to the portions where the gap G is narrow. can improve sexuality. The sealant 514a is applied to the edge of the substrate 502 corresponding to the mounting area of the connector 504 among the edges of the substrate 502. As shown in FIG. Although it is preferable that the coating is applied to the entire edge of the substrate 502 corresponding to the mounting area of the connector 504, even a part of the edge is effective in improving productivity. In addition, the sealant 514b is applied adjacent to both end portions of the sealant 514a in the longitudinal direction of the substrate 502 .

In this embodiment, as shown in FIG. 9, the case where the connector 504 is arranged in the longitudinal center of the board 502 has been described, but the arrangement is not limited to this. For example, the same applies when the connector 504 is arranged at the longitudinal end of the substrate 502 (FIG. 9(a)) or when the connector 504 is arranged at two locations (FIG. 9(b)). be.

1 image forming apparatus 105 optical print head (exposure head)
502 substrate 504 connector 505 holder 514 sealant

Claims (6)

a substrate having a light-emitting element for emitting light for exposing a photoreceptor and a connector to which a flexible flat cable for transmitting a signal for driving the light-emitting element is connected;
a lens array that collects light emitted from the light emitting element onto the photoreceptor;
a holder that holds the substrate and the lens array,
The holder has a base portion formed with an opening into which the lens array is inserted, and both ends of the base portion in the lateral direction of the holder, extending in a direction away from the photoreceptor and extending in the lateral direction. a pair of extensions to which edges of the substrate are bonded;
a first sealant that seals a gap between the edge of the connector mounting area and the pair of extensions, among the edges of the board in the lateral direction;
A second sealant having a viscosity higher than that of the first sealant, wherein the edge of the substrate in the lateral direction other than the region coated with the first sealant and the and a second sealant that seals a gap between the pair of extensions. The first sealant seals a gap between the pair of extending portions and the entire edge of the area where the connector is mounted among the edges of the board in the width direction. Item 1. An exposure head according to item 1. The connector is provided in a region including the center of the substrate in the longitudinal direction of the holder,
3. The method according to claim 1, wherein the second sealant is applied to edges of the substrate adjacent to both end portions of the first sealant in the longitudinal direction. The described exposure head. a photoreceptor;
a substrate having a light-emitting element for emitting light for exposing the photoreceptor and a connector to which a flexible flat cable for transmitting a signal for driving the light-emitting element is connected;
a lens array that collects light emitted from the light emitting element onto the photoreceptor;
a holder that holds the substrate and the lens array,
The holder has a base portion formed with an opening into which the lens array is inserted, and both ends of the base portion in the lateral direction of the holder, extending in a direction away from the photoreceptor and extending in the lateral direction. a pair of extensions to which edges of the substrate are bonded;
a first sealant that seals a gap between the edge of the connector mounting area and the pair of extensions, among the edges of the board in the lateral direction;
A second sealant having a viscosity higher than that of the first sealant, wherein the edge of the substrate in the lateral direction other than the region coated with the first sealant and the and a second sealant that seals a gap between the pair of extensions. The first sealant seals a gap between the pair of extending portions and the entire edge of the area where the connector is mounted among the edges of the board in the width direction. Item 5. The image forming apparatus according to item 4. The connector is provided in a region including the center of the substrate in the longitudinal direction of the holder,
6. The method according to claim 4, wherein the second sealant is applied to edges of the substrate adjacent to both end portions of the first sealant in the longitudinal direction. The described image forming apparatus.

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