Print head and image forming apparatus

Abstract

The present invention provides a print head and image forming apparatus that can suppress warping of the lens array due to adhesive shrinkage. [Solution] The print head 3 comprises a substrate (311) having a plurality of light-emitting elements 31-31, a long lens array 32, and a long lens holding member 313. In a facing region α where the lens array 32 and the lens holding member 313 face each other, the lens array 32 and the lens holding member 313 are bonded to the lens holding member 313 by a plurality of bonding regions H(1)-H(n) in the longitudinal direction L. The plurality of bonding regions H(1)-H(n) include first bonding regions H(2),...,H(n-1) located on one side of the plurality of light-emitting elements 31-31 in the optical axis direction N, and second bonding regions H(1),H(3),...,H(n) located on the other side in the optical axis direction N.

Description

Technical Field

[0001] The present disclosure relates to a print head and an image forming apparatus such as a copying machine, a multifunction peripheral, a printer, and a facsimile apparatus.

Background Art

[0002] Generally, a print head includes a substrate (light emitting element substrate) having a plurality of light emitting elements arranged in a line, a long lens array that condenses the light emitted by the plurality of light emitting elements onto an image carrier (for example, a photoreceptor drum), and a long lens holding member that holds the lens array (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when the lens array and the lens holding member are adhered using an adhesive, the lens array and the lens holding member may be adhered in a plurality of adhesive regions in the longitudinal direction in the opposing region (the region where the lens holding member holds the lens array) where the lens array and the lens holding member face each other. Note that in the regions other than the adhesive regions in the opposing region, the lens array and the lens holding member are in contact (close contact) with each other, and no adhesive is provided. In such a configuration, when the plurality of adhesive regions are offset to one side (one side in the optical axis direction) in the optical axis direction of the plurality of light emitting elements in the opposing region (for example, to one end in the optical axis direction), the adhesive may shrink when the adhesive cures, causing the lens array to warp (curve) in an arcuate shape. Thus, when warping occurs in the lens array, the distance between the lens array and each light emitting element does not become constant at each image height, resulting in a focus shift at a location deviated from the reference position of the lens array.

[0005] In this regard, Patent Document 1 discloses bonding the lens array and the lens holding member (support member) using an adhesive in multiple bonding regions along the longitudinal direction, but it does not mention anything about warping of the lens array due to the shrinkage of the adhesive.

[0006] Therefore, the present disclosure aims to provide a print head and an image forming apparatus that can suppress warping of the lens array due to adhesive shrinkage. [Means for solving the problem]

[0007] To solve the aforementioned problems, the print head according to this disclosure comprises a substrate having a plurality of light-emitting elements arranged in a line, a long lens array for focusing light emitted by the plurality of light-emitting elements onto an image carrier, and a long lens-holding member for holding the lens array, wherein the lens array and the lens-holding member are bonded together in a plurality of adhesive regions in the longitudinal direction in a region where the lens array and the lens-holding member face each other, and the plurality of adhesive regions include a first adhesive region located on one side in the optical axis direction of the plurality of light-emitting elements and a second adhesive region located on the other side in the optical axis direction.

[0008] Furthermore, the image forming apparatus according to this disclosure is characterized by being equipped with the print head according to this disclosure. [Effects of the Invention]

[0009] According to this disclosure, it is possible to suppress warping of the lens array due to the shrinkage of the adhesive. [Brief explanation of the drawing]

[0010] [Figure 1] This is a cross-sectional view showing an image forming apparatus according to this embodiment. [Figure 2]This is a perspective view from the front, looking diagonally upward, showing an example of a print head in the image forming apparatus according to this embodiment, mounted on the main frame. [Figure 3] Figure 2 is a perspective view of the print head supported on the mounting structure, seen from the front and slightly above. [Figure 4] This is a perspective view of the print head from the rear, looking diagonally upwards. [Figure 5] Figure 4 is a perspective view of the print head, seen from the front and slightly below. [Figure 6] Figure 4 is an exploded perspective view of the print head, seen from the front and slightly above. [Figure 7] Figure 4 is an exploded perspective view of the print head, seen from the lower rear side. [Figure 8] This is a cross-sectional perspective view of the print head, seen from the front at an oblique angle above. [Figure 9] This is a cross-section of the print head. [Figure 10] This is a schematic diagram that clearly illustrates the cross-sectional view shown in Figure 9. [Figure 11] This is a plan view showing the light-emitting element panel, flexible circuit board, and printed wiring board that make up a print head, with the flexible circuit board extended in a straight line. [Figure 12] This is a perspective view illustrating an example of the first step in the printhead manufacturing process. [Figure 13] This is a perspective view illustrating an example of the second step in the printhead manufacturing process. [Figure 14] This is a perspective view illustrating an example of the third step in the printhead manufacturing process. [Figure 15] This is a perspective view illustrating an example of the fourth step in the printhead manufacturing process. [Figure 16] This is a perspective view illustrating an example of the fifth step in the printhead manufacturing process. [Figure 17] This is a perspective view illustrating an example of the sixth step in the printhead manufacturing process. [Figure 18]It is a longitudinal sectional view along the longitudinal direction showing an example of a part (upper side) of the lens holding member before the adhesive is applied and a part (lower side) of the lens holding member after the adhesive is applied in this embodiment. [Figure 19] It is a plan view showing an enlarged part of a print head provided with the lens holding member shown in FIG. 18. [Figure 20] It is an explanatory view for explaining the warpage in the first warpage direction within the first adhesion region. [Figure 21] It is an explanatory view for explaining the warpage in the second warpage direction within the second adhesion region. [Figure 22] It is a longitudinal sectional view along the longitudinal direction showing the state before (upper side) and after (lower side) the adhesive is applied in the first adhesion region. [Figure 23] It is a longitudinal sectional view along the longitudinal direction showing the state before (upper side) and after (lower side) the adhesive is applied in the second adhesion region. [Figure 24] It is a longitudinal sectional view along the width direction showing the state after the adhesive is applied in the first adhesion region. [Figure 25] It is a longitudinal sectional view along the width direction showing the state after the adhesive is applied in the second adhesion region. [Figure 26] It is a longitudinal sectional view along the longitudinal direction showing another example of a part of the lens holding member after the adhesive is applied in this embodiment. [Figure 27] It is a longitudinal sectional view along the longitudinal direction showing still another example of a part of the lens holding member after the adhesive is applied in this embodiment. [Figure 28] It is a longitudinal sectional view along the longitudinal direction showing an example of a part (upper side) of the lens holding member before the adhesive is applied and a part (lower side) of the lens holding member after the adhesive is applied in the reference example.

Embodiments for Carrying Out the Invention

[0011] The embodiments of this disclosure will be described below with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions of them will not be repeated.

[0012] (Image forming apparatus) Figure 1 is a cross-sectional view showing an image forming apparatus 100 according to this embodiment. In the figure, the rotation axis direction of the photoreceptor drum 1 is defined as X, the front side as X1, the back side as X2, the direction perpendicular to the rotation axis direction X as the left-right direction Y, the right side as Y1, the left side as Y2, and the up-down direction perpendicular to the rotation axis direction X and the left-right direction Y as Z. The following explanation will be given accordingly.

[0013] The image data handled by the main body 101 of the image forming apparatus 100 corresponds to either a color image using black (K), cyan (C), magenta (M), and yellow (Y), or a monochrome image using a single color (e.g., black). Therefore, four photoreceptor drums 1 (image carriers), chargers 2, print heads 3, developing units 4, primary transfer units 5, and drum cleaning units 6 are provided to form four types of toner images corresponding to each color, and these are associated with black, cyan, magenta, and yellow, forming four image stations Pa, Pb, Pc, and Pd. Note that the image forming apparatus 100 may also be a monochrome image forming apparatus.

[0014] At each image station Pa, Pb, Pc, and Pd, the chargers 2-2 uniformly charge the surface 1a of the photoreceptor drums 1-1, which are rotated in a predetermined rotation direction R, to a predetermined potential. The print heads 3-3 expose the surface 1a of the photoreceptor drums 1-1, forming an electrostatic latent image on the surface 1a of the photoreceptor drums 1-1. The developing device 4 develops the electrostatic latent image on the surface 1a of the photoreceptor drums 1-1, forming a toner image on the surface 1a of the photoreceptor drums 1-1. As a result, toner images of each color are formed on the surface 1a of each photoreceptor drum 1-1. The drum cleaning devices 6-6 remove and recover residual toner from the surface 1a of the photoreceptor drums 1-1. The primary transfer devices 5-5 sequentially transfer the toner images of each color on the surface 1a of each photoreceptor drum 1-1 onto an intermediate transfer belt 23 that moves circulating by the drive rollers 21 and driven rollers 22 of the belt drive device 20, forming a color toner image on the intermediate transfer belt 23. The belt cleaning device 7 removes and recovers residual toner from the intermediate transfer belt 23.

[0015] A transfer nip section TN is formed between the intermediate transfer belt 23 and the transfer roller 81 of the secondary transfer device 8. The transfer roller 81 of the secondary transfer device 8 traps the sheet P, such as recording paper, which has been transported through the sheet transport path 11, in the transfer nip section TN and transports it together with the intermediate transfer belt 23, while transferring the color toner image on the surface of the intermediate transfer belt 23 onto the sheet P. The fixing device 9 traps the sheet P between a fixing member (fixing belt 91 in this example) and a pressurizing member (pressure roller 92 in this example), heats and pressurizes it, and fixes the color toner image on the sheet P.

[0016] The sheet P is pulled out from the paper feed cassette 13 by the pickup roller 12, transported through the sheet transport path 11, passes through the secondary transfer device 8 and the fixing device 9, and is delivered to the discharge tray 15 via the discharge roller 14. The sheet transport path 11 is equipped with a registration roller 16 and the like. The registration roller 16 temporarily stops the sheet P, aligns the leading edge of the sheet P, and then starts transporting the sheet P in accordance with the timing of toner image transfer at the transfer nip section TN between the intermediate transfer belt 23 and the transfer roller 81.

[0017] Figure 2 is a perspective view of an example of print heads 3-3 in the image forming apparatus 100 according to this embodiment, mounted on the main frame FL (FL1-FL3), viewed from diagonally above the front side X1. Figure 3 is a perspective view of the print head 3 shown in Figure 2, supported by the mounting section 210, viewed from diagonally above the front side X1. Figure 4 is a perspective view of the print head 3 viewed from diagonally above the rear side X2. Figure 5 is a perspective view of the print head 3 shown in Figure 4, viewed from diagonally below the front side X1. Figures 6 and 7 are exploded perspective views of the print head 3 shown in Figure 4, viewed from diagonally above the front side X1 and diagonally below the rear side X2, respectively.

[0018] Figure 8 is a cross-sectional perspective view of the print head 3 viewed from diagonally above the front. Figure 9 is a cross-sectional view of the print head 3. Figure 10 is a schematic diagram that clearly illustrates the cross-sectional view shown in Figure 9. Figure 11 is a plan view showing the state in which the flexible circuit board 312a is extended in a straight line in the light-emitting element panel 311 (light-emitting element substrate), flexible circuit board 312a, and printed wiring board 312b that constitute the print head 3.

[0019] In the following description, the multiple light-emitting elements 31-31 in the print heads 3-3 will be described as organic light-emitting diodes (OLEDs; hereinafter simply referred to as OLEDs). However, the light-emitting elements 31-31 are not limited to OLEDs, and may also be inorganic light-emitting diodes (LEDs), or light-emitting elements such as nano-light-emitting diodes (nano-scale light-emitting diodes), which are smaller than a micrometer.

[0020] Since each print head 3-3 etc. has the same configuration, they are shown in a single diagram in Figures 3 to 11, and in the following explanation, each print head 3-3 etc. will simply be referred to as print head 3 etc.

[0021] The image forming apparatus 100 according to this embodiment comprises a photoreceptor drum 1 and a long print head 3. The print head 3 comprises a light-emitting element panel 311 and a lens array 32. The light-emitting element panel 311 has a plurality of light-emitting elements 31-31 (see Figures 9 to 11). The light-emitting elements 31-31 emit light to expose the surface 1a of the photoreceptor drum 1. The light-emitting elements 31-31 are arranged in a line along the longitudinal direction L of the print head 3. In this example, the light-emitting element panel 311 is a film-like panel (flexible OLED panel) (light-emitting element panel) on which OLED elements (31-31) are mounted. This makes it possible to miniaturize and reduce the cost of the print head 3.

[0022] The lens array 32 extends in the longitudinal direction L and focuses the light emitted by the light-emitting elements 31-31 onto the surface 1a of the photoreceptor drum 1. The lens array 32 is positioned opposite the light-emitting elements 31-31.

[0023] A print head 3 is installed on the mounting section 210. The mounting section 210 is mounted between the main frame FLs of the image forming apparatus main body 101 (see Figure 1) (in this example, between the main frame FL1 on the front side X1 and the main frame FL2 on the rear side X2).

[0024] In this example, the main frame FL3 is installed between the main frames FL1 and FL2, along the rotational axis direction X and the left-right direction Y. The installation section 210 is placed on the main frame FL3.

[0025] <Printhead> As shown in Figures 8 to 11, the print head 3 further comprises a drive member 312, a lens holding member 313, a fixing member 314 (base member), and a main body member 315. The fixing member 314 and the main body member 315 constitute a support member 316. The drive member 312 drives the light-emitting elements 31-31. The lens holding member 313 holds the lens array 32. The fixing member 314 fixes the lens holding member 313 while the light-emitting element panel 311 is fixed. The main body member 315 holds the drive member 312, the lens holding member 313, and the fixing member 314.

[0026] In this example, the drive member 312 includes a flexible circuit board 312a (connection cable member), a printed wiring board 312b (PWB: Printed Wiring Board) (connection board), a drive circuit element 312c, and a protective member 312d. One end of the connection cable member (312a) is connected to one end of the light-emitting element panel 311, and the other end is connected to one end of the printed wiring board 312b. The connection cable member (312a) is a flexible circuit board (COF: Chip on Film) on which a drive circuit element 312c (driver IC) that drives the OLED elements (31~31) on the light-emitting element panel 311 is mounted on a film. The printed wiring board 312b connected to the connection cable member (312a) has an input terminal 312b1 (see Figure 10) (connector terminal) and is connected to a connector CN (see Figure 10) via the input terminal 312b1. The protective member 312d protects the exposed portions of the light-emitting element panel 311 and the connection cable member (312a). Connector CN is connected to an image processing device (not shown) provided on the main body 101 of the image forming apparatus. In Figure 10, the light-emitting elements 31-31 are shown protruding from the outer surface of the light-emitting element panel 311, but this is for illustrative purposes only. In reality, as shown in Figure 9, they are located on the inside of the light-emitting element panel 311 so as not to protrude from the outer surface (for example, by deposition).

[0027] The lens holding member 313 is a frame-shaped member that surrounds the outer peripheral surfaces 32a-32a (see Figures 6 and 7) of the lens array 32 along the optical axis direction N of the light-emitting elements 31-31. Here, the optical axis direction N is the direction (thickness direction) perpendicular to both the longitudinal direction L and the width direction M of the print head 3. The width direction M is the direction perpendicular to the arrangement direction S along the line-shaped direction of the multiple light-emitting elements 31-31. The lens array 32 is inserted into the inner surface 313a of the frame-shaped lens holding member 313. At least a portion of the outer peripheral surfaces 32a-32a (in this example, the sides 32a1, 32a1 along the longitudinal direction L) of the lens array 32 is held by the lens holding member 313, and at least some locations (multiple locations in this example) are bonded with an adhesive (e.g., UV-curing adhesive). In addition, the area around the joint between the lens array 32 and the lens holding member 313 is sealed with a caulking agent (caulking resin). This effectively prevents foreign matter such as dust from entering the lens holding member 313 from the joint between the lens array 32 and the lens holding member 313.

[0028] The fixing member 314 is formed in a rectangular parallelepiped shape. The surface 314a of the fixing member 314 on the side of the photoreceptor drum 1 (one side N1) in the optical axis direction N is bonded to the back surface of the light-emitting element panel 311, which is equipped with light-emitting elements 31-31, on the side opposite to the light-emitting elements 31-31, by an adhesive member E (for example, double-sided adhesive tape) (see Figure 10). The back surface 313c of the lens holding member 313 is fixed to the panel surface 311a of the light-emitting element panel 311, on the side opposite to the fixing member 314. The area around the joint between the lens holding member 313 and the light-emitting element panel 311 is sealed with a caulking agent (caulking resin). This effectively prevents foreign matter such as dust from entering the lens holding member 313 from the joint between the lens holding member 313 and the light-emitting element panel 311.

[0029] The relative positions of the multiple light-emitting elements 31-31 and the lens array 32 (positions in the longitudinal direction L, width direction M, and optical axis direction N) are pre-positioned and adjusted using jigs or the like during the production process.

[0030] The main body member 315 has an arrangement portion 315a, a bent portion 315b, and a panel guide portion 315c. The arrangement portion 315a, the bent portion 315b, and the panel guide portion 315c are integrally formed.

[0031] The placement section 315a is for positioning the fixing member 314. The placement section 315a is provided with a placement surface 315a1 on which the fixing member 314 is positioned such that the back surface 314b of the fixing member 314 on the erection section 210 side is in contact with it. This ensures that the fixing member 314 is securely positioned on the placement surface 315a1 of the placement section 315a. The placement surface 315a1 of the placement section 315a is provided with a plurality (two) of positioning protrusions or recesses (positioning protrusions 315a2, 315a2 in this example) (see Figure 6). The back surface 314b of the fixing member 314 is provided with positioning recesses or protrusions (positioning recesses 314c, 314c in this example) (see Figure 7) that correspond to the plurality (two) of positioning protrusions or recesses (315a2, 315a2). This ensures that the fixing member 314 is securely positioned relative to the main body member 315. Furthermore, the placement section 315a is provided with a plurality (two) of holding sections 315a3, 315a3 (see Figures 6, 7, and 9). The placement section 315a and the holding sections 315a3, 315a3 are integrally formed. The holding sections 315a3, 315a3 detachably hold the fixing member 314 in the placement section 315a. The holding sections 315a3, 315a3 restrict the movement of the fixing member 314 toward the light-emitting elements 31-31 side (one side N1) in the optical axis direction N. The holding sections 315a3, 315a3 have a locking section 315a31 (see Figure 9) that locks onto the surface 314a of the fixing member 314.

[0032] The bent portion 315b is bent at an acute angle (for example, 60 degrees or less, about 50 degrees in this example) relative to the placement portion 315a. A printed circuit board 312b is fixed to the surface 315b1 (inner surface) of the bent portion 315b that faces the placement portion 315a. The input terminal 312b1 is provided at the entrance side (opening SPa side) end of the space SP between the placement portion 315a and the bent portion 315b of the printed circuit board 312b, and the connector CN is connected facing the space SP.

[0033] The panel guide portion 315c has a curved portion 315c1 that folds back a film-like overhang 317 from the support member 316 (314, 315) toward the space SP. The curved portion 315c1 is curved such that the lens holding member 313 side of the overhang 317 folds back by 180 degrees or more (in this example, between the light-emitting element panel 311 and the connecting cable member (312a)). The curved portion 315c1 protrudes from the lens holding member 313 on either one side M1 or the other side M2 ​​in the width direction M (in this example, the other side M2). The panel portion 311b of the light-emitting element panel 311 on the connecting cable member (312a) side and the portion of the connecting cable member (312a) on the light-emitting element panel 311 side are bonded to the curved portion 315c1 by an adhesive member E. As a result, the curved portion 315c1 can reliably fold back the protruding portion 317 [in this example, the connecting cable member (312a)] into the space SP. The protective member 312d is opposite the portion of the protruding portion 317 corresponding to the curved portion 315c1 and is curved along the curved portion 315c1. As shown in Figures 6 and 7, the protective member 312d is fastened to the fastened portion 315e (female screw) of the main body member 315 by fastening member SC1 (male screw) through the through hole 312e1 of the holder 312e and the through hole 312d1 of the protective member 312d at one side L1 in the longitudinal direction L. This allows the end of the protective member 312d at one side L1 in the longitudinal direction L to be fixed to the main body member 315.

[0034] Furthermore, on the other side L2 in the longitudinal direction L, the protective member 312d is fastened to the fastened portion 315e of the main body member 315 by inserting the fastening member SC1 through the through hole 312d1 of the protective member 312d. This allows the end of the other side L2 in the longitudinal direction L of the protective member 312d to be fixed to the main body member 315. Also, on the other side L2 in the longitudinal direction L of the printed circuit board 312b, the positioning hole 312b2 of the printed circuit board 312b is positioned on the positioning projection 315b2 of the bent portion 315b. In this state, on one side L1 in the longitudinal direction L, the printed circuit board 312b is fastened to the fastened portion 312e2 (female screw) of the holder 312e by inserting the fastening member SC2 (male screw) through the through hole 315b3 of the bent portion 315b and the through recess 312b3 of the printed circuit board 312b. This allows the protective member 312d to be held in a position on the bent portion 315b.

[0035] The end of a portion of the protruding part 317 (connecting cable member (312a)) provided within the space SP that is on the printed circuit board 312b side is folded back at the corner between the placement part 315a and the bent part 315b and connected to the printed circuit board 312b.

[0036] The drive circuit element 312c is provided on the side of the arrangement portion 315a of the connecting cable member (312a). A recess 315a5 is provided on the surface 315a4 (inner surface) of the arrangement portion 315a facing the bent portion 315b to prevent interference with the drive circuit element 312c of the connecting cable member (312a).

[0037] Furthermore, the main body member 315 is provided with a pair of side plate portions 315f and 315g (see Figures 6 and 7) that close both ends of the space SP in the longitudinal direction L.

[0038] Next, the manufacturing method of the print head 3 will be described below with reference to Figures 12 to 17.

[0039] Figures 12 to 17 are perspective views illustrating examples of the first to sixth steps in the manufacturing process of the print head 3. Figures 12 to 17 show the steps from mounting the lens array 32 on the lens holding member 313, mounting the light-emitting element panel 311 on the fixing member 314, and mounting the lens holding member 313 on the light-emitting element panel 311.

[0040] In the manufacturing method of the print head 3, first, as shown in Figure 12, the lens array 32 is inserted into the inner surface (313a) of the lens holding member 313 (in this example, a through-elongated hole 3131 along the vertical Z direction) (first step).

[0041] Next, as shown in Figure 13, the UV-curing adhesive F is evenly applied to multiple locations in the surrounding area between the lens array 32 and the lens holding member 313 using the dispenser 410, and then the UV-curing adhesive F is cured by irradiating it with ultraviolet light (UV) using the UV irradiation device 420 (second step). This ensures that the lens array 32 is securely held by the lens holding member 313.

[0042] Next, as shown in Figure 14, the caulking agent G (caulking resin) is applied to the surrounding area between the lens array 32 and the lens holding member 313 using the caulking agent application device 430 to seal the gap between the lens array 32 and the lens holding member 313 (third step). This prevents foreign matter such as dust from entering through the gap between the lens array 32 and the lens holding member 313.

[0043] Next, as shown in Figure 15, the double-sided adhesive tape (E) (double-sided adhesive sheet) is attached to the side (314a) of the fixing member 314 with the protective seal Ea on one side using the roller pressing device 440 (fourth step).

[0044] Next, as shown in Figure 16, the protective seal Ea on one side of the double-sided adhesive tape (E) is peeled off, and with the multiple light-emitting elements 31-31 on the light-emitting element panel 311 positioned at the reference position on the fixing member 314, the light-emitting element panel 311 is attached to the fixing member 314 using the roller pressing device 440 (5th step).

[0045] Next, as shown in Figure 17, the lens holding member 313, which holds the lens array 32 manufactured in the third step (see Figure 14), is placed on the light-emitting element panel 311 attached to the fixing member 314. The sealant G (sealing resin) is then applied to the surrounding area between the lens holding member 313 and the light-emitting element panel 311 using the sealant application device 430 to seal the gap between the lens holding member 313 and the light-emitting element panel 311 (sixth step). This prevents foreign matter such as dust from entering through the gap between the lens holding member 313 and the light-emitting element panel 311.

[0046] (Regarding this embodiment) As shown in Figures 9 to 11, the print head 3 according to this embodiment includes a substrate (311) (see Figures 9 and 10) having a plurality of light-emitting elements 31 to 31 arranged in a line, a lens array 32 that focuses the light emitted by the plurality of light-emitting elements 31 to 31 onto a photoreceptor drum 1 (an example of an image carrier) (see Figure 1), and a lens holding member 313 that holds the lens array 32.

[0047] Figure 28 is a longitudinal cross-sectional view along the longitudinal direction L, showing an example of a part (upper side) of the lens holding member 313X before adhesive (UV-curing adhesive F in this example) is applied to the lens array 32 in a reference example, and a part (lower side) of the lens holding member 313X after adhesive (F) is applied. Figure 18 is a longitudinal cross-sectional view along the longitudinal direction L, showing an example of a part (upper side) of the lens holding member 313 that holds the lens array 32 before adhesive (UV-curing adhesive F in this example) is applied, and a part (lower side) of the lens holding member 313 after adhesive (F) is applied in this embodiment. Figure 19 is a plan view showing an enlarged portion of the print head 3 equipped with the lens holding member 313 shown in Figure 18.

[0048] Incidentally, when bonding the lens array 32 and the lens holding member 313X using adhesive (F), as shown in Figures 28, 18, and 19, the lens array 32 and the lens holding members 313, 313X may be bonded in multiple bonding regions H(1) to H(n) (where n is an integer of 2 or more) in the longitudinal direction L within the opposing region α (the region where the lens holding members 313, 313X hold the lens array 32). Note that in regions of the opposing region α other than the bonding regions H(1) to H(n), the lens array 32 and the lens holding members 313, 313X are in contact (tightly attached), and no adhesive (F) is provided.

[0049] As shown in Figure 28, in the reference example lens array 32X, if multiple adhesive regions H(1) to H(n) are located on one side N1 (the photoreceptor drum 1 side in the example shown in Figure 28) in the optical axis direction N of multiple light-emitting elements 31 to 31 (one end in the optical axis direction N in the example shown in Figure 28), the following disadvantages arise.

[0050] In other words, when the adhesive (F) hardens, the adhesive (F) shrinks. As a result, the individual adhesive regions H(1) to H(n) are pulled toward the center in the longitudinal direction L (arrows T1, T2 direction) due to the shrinkage of the adhesive (F), causing the adhesive regions H(1) to H(n) on both ends 313d, 313d in the longitudinal direction L of the lens holding member 313 to move inward (arrows V1, V2 direction), and consequently the lens holding member 313X may bend (curve) into an arc shape (see dashed line in Figure 28).

[0051] Consequently, since the lens holding member 313X is generally more rigid than the lens array 32, the lens array 32 bonded to the lens holding member 313X moves in the same way as the curved lens holding member 313X, so that the bonded areas H(1)~H(n) on both ends 32d, 32d in the longitudinal direction L in the optical axis direction N face inward (in the direction of arrows V1, V2), and as a result the lens array 32 bends (curves) into an arc shape (see dashed line in Figure 28).

[0052] Thus, when the lens array 32 warps, the distance between the lens array 32 and the individual light-emitting elements 31-31 becomes inconsistent at each image height, leading to a focus shift at points where the lens array 32 is offset from its reference position.

[0053] In this embodiment, the multiple adhesive regions H(1) to H(n) include a first adhesive region H(2), ..., H(n-1 or n) located on one side N1 in the optical axis direction N (in this example, the photoreceptor drum 1 side), and a second adhesive region H(1), H(3), ..., H(n-2), H(n or n-1) located on the other side N2 in the optical axis direction N (in this example, the substrate (311) side). Here, when n is odd, the end of the first adhesive region is H(n-1) and the end of the second adhesive region is H(n). When n is even, the end of the first adhesive region is H(n) and the end of the second adhesive region is H(n-1). In the example shown in Figure 18, n is odd.

[0054] According to this embodiment, in the opposing region α, the first adhesive regions H(2), ..., H(n-1) are located on one side N1 in the optical axis direction N, and the second adhesive regions H(1), H(3), ..., H(n) are located on the other side N2 in the optical axis direction N. Therefore, even if the adhesive (F) shrinks when it hardens and the individual adhesive regions H(1) to H(n) are pulled toward the center in the longitudinal direction L (arrows T1, T2 direction) due to the shrinkage of the adhesive (F) to (F), the tensile force in the longitudinal direction L can be canceled out between the first adhesive regions H(2), ..., H(n-1) and the second adhesive regions H(1), H(3), ..., H(n). Therefore, it is possible to suppress the bending of the lens holding member 313 into an arc shape, and consequently, the bending of the lens array 32 into an arc shape.

[0055] Here, the cured adhesive (F) in the first bonding region H(2),...,H(n-1) and the second bonding region H(1),H(3),...,H(n) is defined as having a size of approximately 1 mm or less in the optical axis direction N, specifically about 0.3 mm to 0.5 mm, and a size of approximately 1 mm or less in the short direction (width direction M), specifically about 0.3 mm to 0.5 mm.

[0056] <First Embodiment> Figure 20 is an explanatory diagram illustrating the curvature in the first curvature direction W1 within the first bonding region H(2), ..., H(n-1). Figure 21 is an explanatory diagram illustrating the curvature in the second curvature direction W2 within the second bonding region H(1), H(3), ..., H(n).

[0057] As shown in Figure 20, the first edges Q1, Q1 at both ends in the longitudinal direction L and one end N1 in the optical axis direction N of the first adhesive regions H(2), ..., H(n-1) tend to move toward the center in the longitudinal direction L, and each portion of the first adhesive regions H(2), ..., H(n-1) of the lens holding member 313 tends to bend in a first curvature direction W1 with the other side N2 in the optical axis direction N being convex. On the other hand, as shown in Figure 21, the second edges Q2, Q2 at both ends in the longitudinal direction L and the other end N2 in the optical axis direction N of the second adhesive regions H(1), H(3), ..., H(n) tend to move toward the center in the longitudinal direction L, and each portion of the second adhesive regions H(1), H(3), ..., H(n) of the lens holding member 313 tends to bend in a second curvature direction W2 with one side N1 in the optical axis direction N being convex.

[0058] In this respect, in this embodiment, the first adhesive regions H(2),...,H(n-1) and the second adhesive regions H(1),H(3),...,H(n) are alternately located in the longitudinal direction L.

[0059] In this configuration, the first bonding regions H(2),...,H(n-1) and the second bonding regions H(1),H(3),...,H(n) are alternately located in the longitudinal direction L, so as shown in Figures 18 to 21, the curvature directions (first curvature direction W1 and second curvature direction W2) can be alternately made different between the first bonding regions H(2),...,H(n-1) and the second bonding regions H(1),H(3),...,H(n). This allows the tensile forces in the longitudinal direction L to alternately cancel each other out between adjacent first bonding regions (2),...,H(n-1) and second bonding regions H(1),H(3),...,H(n). Therefore, it is possible to further suppress the curvature of the lens holding member 313 into an arc shape, and consequently, the curvature of the lens array 32 into an arc shape.

[0060] Figure 22 is a longitudinal cross-sectional view along the longitudinal direction L showing the first bonding region H(2), ..., H(n-1) before (top) and after (bottom) application of adhesive (F). Figure 23 is a longitudinal cross-sectional view along the longitudinal direction L showing the second bonding region H(1), H(3), ..., H(n) before (top) and after (bottom) application of adhesive (F). Figure 24 is a longitudinal cross-sectional view along the width direction M showing the first bonding region H(2), ..., H(n-1) after application of adhesive (F). Figure 25 is a longitudinal cross-sectional view along the width direction M showing the second bonding region H(1), H(3), ..., H(n) after application of adhesive (F).

[0061] In this embodiment, at least one of the lens holding member 313 and the lens array 32 (in this example, the lens holding member 313) is provided with a plurality of recesses 318(1) to 318(n) for applying adhesive (F).

[0062] The multiple recesses 318(1) to 318(n) include first recesses 318(2), ..., 318(n-1) that adhere to the first adhesive region H(2), ..., H(n-1), and second recesses 318(1), 318(3), ..., 318(n) that adhere to the second adhesive region H(1), H(3), ..., H(n).

[0063] The first recesses 318(2), ..., 318(n-1) and the second recesses 318(1), 318(3), ..., 318(n) all share the same depth direction (the first depth direction D1 on one side N1 or the second depth direction D2 on the other side N2 in the optical axis direction N; in this example, the second depth direction D2).

[0064] The second depth h2 (see Figure 25) of the second recesses 318(1), 318(3), ..., 318(n) is deeper than the first depth h1 (see Figure 24) of the first recesses 318(2), ..., 318(n-1).

[0065] In this configuration, when applying the uncured adhesive (F) to the first bonding region H(2), ..., H(n-1) of the first recess 318(2), ..., 318(n-1) and the second bonding region H(1), H(3), ..., H(n) of the second recess 318(1), 318(3), ..., 318(n), as shown in Figures 22 and 23, first, the nozzle 411 of the dispenser 410 is inserted into the first recess 318(2), ..., 318(n-1) and the second recess 318(1), 318(3), ..., 318(n), and the nozzle 411 reaches the first bonding region H(2), ..., H(n-1) and the second bonding region H(1), H(3), ..., H(n). Next, a regular amount of adhesive (F) is applied to the first bonding region H(2),...,H(n-1) and the second bonding region H(1),H(3),...,H(n), not exceeding the amounts of the first bonding region H(2),...,H(n-1) and the second bonding region H(1),H(3),...,H(n).

[0066] With this configuration, the uncured adhesive (F) can be applied to the first bonding regions H(2),...,H(n-1) and the second bonding regions H(1),H(3),...,H(n) from the same depth direction (second depth direction D2 in this example), thereby simplifying the adhesive (F) application process. Furthermore, since the second depth h2 is deeper than the first depth h1, the first bonding regions H(2),...,H(n-1) can be easily positioned on one side N1 in the optical axis direction N, and the second bonding regions H(1),H(3),...,H(n) can be easily positioned on the other side N2 in the optical axis direction N in the opposing region α.

[0067] Here, the shape of the first recesses 318(2), ..., 318(n-1) and the second recesses 318(1), 318(3), ..., 318(n) is not particularly limited as long as adhesive (F) can be applied to them. As in this embodiment, the bottom may be rectangular, or it may be, for example, arc-shaped. The same applies to the first recesses 318(2), ..., 318(n-1) and the second recesses 318(1), 318(3), ..., 318(n) of the third embodiment described later.

[0068] <Second Embodiment> Figure 26 is a longitudinal cross-sectional view along the longitudinal direction L showing another example of a part of the lens holding member 313 after adhesive (F) has been applied in this embodiment.

[0069] In this embodiment, the multiple adhesive regions H(1) to H(n) include a first adhesive region H(2), ..., H(n or n-1) located on one side N1 in the optical axis direction N, and a second adhesive region H(1), H(3), ..., H(n-2), H(n-1 or n) located on the other side N2 in the optical axis direction N. Here, when n is even, the end of the first adhesive region is H(n) and the end of the second adhesive region is H(n-1). When n is odd, the end of the first adhesive region is H(n-1) and the end of the second adhesive region is H(n). In the example shown in Figure 26, n is even.

[0070] According to this embodiment, in the opposing region α, the first adhesive regions H(2), ..., H(n-1) are located on one side N1 in the optical axis direction N, and the second adhesive regions H(1), H(3), ..., H(n) are located on the other side N2 in the optical axis direction N. Therefore, even if the adhesive (F) shrinks when it hardens and the individual adhesive regions H(1) to H(n) are pulled toward the center in the longitudinal direction L due to the shrinkage of the adhesive (F) to (F), the tensile force in the longitudinal direction L can be canceled out between the first adhesive regions H(2), ..., H(n-1) and the second adhesive regions H(1), H(3), ..., H(n). Therefore, it is possible to suppress the bending of the lens holding member 313 into an arc shape, and consequently, the bending of the lens array 32 into an arc shape.

[0071] In this embodiment, at least one of the lens holding member 313 and the lens array 32 (in this example, the lens holding member 313) is provided with a plurality of recesses 318(1) to 318(n) for applying adhesive (F).

[0072] The multiple recesses 318(1) to 318(n) include first recesses 318(2), ..., 318(n-1) that adhere to the first adhesive region H(2), ..., H(n-1), and second recesses 318(1), 318(3), ..., 318(n) that adhere to the second adhesive region H(1), H(3), ..., H(n).

[0073] The first recesses 318(2), ..., 318(n-1) and the second recesses 318(1), 318(3), ..., 318(n) have depth directions that are different from each other. In this example, the first recesses 318(2), ..., 318(n-1) have a second depth direction D2 that is deeper on the other side N2 in the optical axis direction N, and the second recesses 318(1), 318(3), ..., 318(n) have a first depth direction D1 that is deeper on one side N1 in the optical axis direction N. .

[0074] In this configuration, the uncured adhesive (F) is applied to the first bonding region H(2), ..., H(n-1) from the second depth direction D2, and the uncured adhesive (F) is applied to the second bonding region H(1), H(3), ..., H(n) from the first depth direction D1, which is different from the second depth direction D2. Therefore, the second depth h2 (see Figure 26) of the second bonding region H(1), H(3), ..., H(n) can be made shallower than the second depth h2 (see Figure 25) of the second bonding region H(1), H(3), ..., H(n) according to the second embodiment, thereby facilitating the application of the uncured adhesive (F) to the second bonding region H(1), H(3), ..., H(n).

[0075] In this embodiment, the first depth h1 (see Figure 26) of the first recess 318(2), ..., 318(n-1) and the second depth h2 of the second recess 318(1), 318(3), ..., 318(n) are the same depth.

[0076] In this configuration, by making the first depth h1 and the second depth h2 the same depth, it is possible to further facilitate the application of the uncured adhesive (F) to the second bonding regions H(1), H(3), ..., H(n).

[0077] <Third Embodiment> Figure 27 is a longitudinal cross-sectional view along the longitudinal direction L showing yet another example of a part of the lens holding member 313 after adhesive (F) has been applied in this embodiment.

[0078] In this embodiment, at least a portion (in this example, the entirety) of the first adhesive regions H(2),...,H(n-1) and the second adhesive regions H(1),H(3),...,H(n) overlap in the longitudinal direction L.

[0079] In this configuration, the lens array 32 and the lens holding member 313 can be firmly fixed together by the cured adhesive (F) at the overlapping position of the first bonding region H(2),...,H(n-1) and the second bonding region H(1),H(3),...,H(n).

[0080] <Fourth Embodiment> In this embodiment, the first size d1 in the longitudinal direction L of the first adhesive region H(2), ..., H(m) (m1=n-1 in the first embodiment, and m1=n in the second and third embodiments) is the same in all embodiments from the first to the third embodiment (see Figures 18, 26, and 27). The second size d2 in the longitudinal direction L of the second adhesive region H(1), H(3), ..., H(m2) (m2=n in the first embodiment, and m1=n-1 in the second and third embodiments) is the same in all embodiments (see Figures 18, 26, and 27). The first size d1 and the second size d2 are the same.

[0081] In this configuration, by making the first size d1 and the second size d2 the same size, the first bonding regions H(2),...,H(m1) and the second bonding regions H(1),H(3),...,H(m2) can be arranged in a balanced manner along the longitudinal direction L, further suppressing the bending of the lens array 32 into an arc shape.

[0082] <Fifth Embodiment> In this embodiment, the number of first adhesive regions H(2), ..., H(m1) and second adhesive regions H(1), H(3), ..., H(m2) are all the same in the first to fourth embodiments.

[0083] In this configuration, by making the number of first adhesive regions H(2),...,H(m1) and second adhesive regions H(1),H(3),...,H(m2) the same, the first adhesive regions H(2),...,H(m1) and the second adhesive regions H(1),H(3),...,H(m2) can be arranged in a balanced manner along the longitudinal direction L, further suppressing the bending of the lens array 32 into an arc shape.

[0084] <Sixth Embodiment> In this embodiment, the first distance e1 between adjacent first adhesive regions [H(2), H(4)], ..., [H(m1-2), H(m1)] (see Figures 18, 26, and 27) is the same in all embodiments from the first to the fifth embodiment.

[0085] In this configuration, by setting the first distance e1 to the same distance in all cases, the first bonding regions H(2), ..., H(m1) can be arranged in a balanced manner along the longitudinal direction L, further suppressing the bending of the lens array 32 into an arc shape.

[0086] <Seventh Embodiment> In this embodiment, from the first to the sixth embodiment, the second distance e2 between adjacent second adhesive regions [H(1), H(3)], ..., [H(m2-2), H(m2)] (see Figures 18, 26, and 27) is the same in all cases.

[0087] In this configuration, by setting the second distance e2 to the same distance in all cases, the second bonding regions H(1), H(3), ..., H(m2) can be arranged in a balanced manner along the longitudinal direction L, further suppressing the bending of the lens array 32 into an arc shape.

[0088] <Eighth Embodiment> In this embodiment, the first distance e1 and the second distance e2 are the same distance.

[0089] In this configuration, the first distance e1 between adjacent first adhesive regions [H(2), H(4)], ..., [H(m1-2), H(m1)] is set to be the same, and the second distance e2 between adjacent second adhesive regions [H(1), H(3)], ..., [H(m2-2), H(m2)] is set to be the same. Furthermore, by setting the first distance e1 and the second distance e2 to be the same, the first adhesive regions H(2), ..., H(m1) and the second adhesive regions H(1), H(3), ..., H(m2) can be arranged in a more balanced manner along the longitudinal direction L, and the bending of the lens array 32 into an arc shape can be further suppressed.

[0090] <Ninth Embodiment> In this embodiment, from the first to the eighth embodiment, the first adhesive region H(2),...,H(m1) and the second adhesive region H(1),H(3),...,H(m2) have equal distances f1,f2 from a virtual central line β along the longitudinal direction L located in the center in the optical axis direction N (see Figures 22, 23, 26, and 27).

[0091] In this configuration, the first bonding regions H(2),...,H(m1) and the second bonding regions H(1),H(3),...,H(m2) can be arranged in a more balanced manner along the optical axis N, further suppressing the bending of the lens array 32 into an arc shape.

[0092] <Tenth Embodiment> In this embodiment, from the first to the ninth embodiment, the central position of the length g (see Figures 18, 26, and 27) in the longitudinal direction L of the entire adhesive region H(1) to H(mn) coincides with the central position in the longitudinal direction L of the lens holding member 313 and / or lens array 32.

[0093] In this configuration, the curvature of the lens array 32 can be uniformly suppressed with respect to the central position in the longitudinal direction L.

[0094] <Embodiment 11> In this embodiment, in the first to tenth embodiments, the lens array 32 and the lens holding member 313 are bonded together in the first bonding regions H(2), ..., H(m1) and the second bonding regions H(1), H(3), ..., H(m2) on both sides in the short direction (width direction M) (see Figure 19). In the example shown in Figure 19, the first bonding regions H(2), ..., H(m1) on both sides and the second bonding regions H(1), H(3), ..., H(m2) on both sides overlap in the longitudinal direction L.

[0095] In this configuration, the lens array 32 and the lens holding member 313 are bonded together at the first bonding regions H(2),...,H(m1) and the second bonding regions H(1),H(3),...,H(m2) on both sides in the short direction (width direction M). This allows the first bonding regions H(2),...,H(m1) and the second bonding regions H(1),H(3),...,H(m2) to be arranged in a more balanced manner in the short direction (M), further suppressing the bending of the lens array 32 into an arc shape. Furthermore, the bonded adhesive (F) after curing firmly fixes the lens array 32 and the lens holding member 313 at the first bonding regions H(2),...,H(m1) and the second bonding regions H(1),H(3),...,H(m2) on both sides in the short direction (M).

[0096] More specifically, the following configurations can be used in the first bonding regions H(2), ..., H(m1) and the second bonding regions H(1), H(3), ..., H(m2) on both sides in the short direction (M). That is, [a] An example can be given in which at least a portion of the first adhesive region H(2),...,H(m1) on one side and the second adhesive region H(1),H(3),...,H(m2) on the other side overlap in the longitudinal direction L. In this case, it is preferable that the central portions of the first adhesive region H(2),...,H(m1) and the second adhesive region H(1),H(3),...,H(m2) in the longitudinal direction L coincide.

[0097] [b] An example can be given in which at least a portion of the first adhesive regions H(2),...,H(m1) on one side and the first adhesive regions H(2),...,H(m1) on the other side overlap in the longitudinal direction L. In this case, it is preferable that the central portions of the first adhesive regions H(2),...,H(m1) and the first adhesive regions H(2),...,H(m1) in the longitudinal direction L coincide.

[0098] [c] An example can be given in which at least a portion of the second adhesive regions H(1), H(3), ..., H(m2) on one side and the second adhesive regions H(1), H(3), ..., H(m2) on the other side overlap in the longitudinal direction. In this case, it is preferable that the central portions of the second adhesive regions H(1), H(3), ..., H(m2) and the second adhesive regions H(1), H(3), ..., H(m2) in the longitudinal direction L coincide.

[0099] [d] An example can be given in which the first adhesive regions H(2), ..., H(m1) on one side and the second adhesive regions H(1), H(3), ..., H(m2) on the other side do not overlap in the longitudinal direction.

[0100] [e] An example can be given in which the first adhesive regions H(2),...,H(m1) on one side and the first adhesive regions H(2),...,H(m1) on the other side do not overlap in the longitudinal direction.

[0101] [f] An example can be given in which the second adhesive regions H(1), H(3), ..., H(m2) on one side and the second adhesive regions H(1), H(3), ..., H(m2) on the other side do not overlap in the longitudinal direction.

[0102] In the embodiments described in [d] to [f] above, it is preferable that the second adhesive regions H(1), H(3), ..., H(m2) are located in the center of the longitudinal direction L between adjacent first adhesive regions [H(2), H(4)], ..., [H(m1-2), H(m1)], and that the first adhesive regions H(2), ..., H(m1) are located in the center of the longitudinal direction L between adjacent second adhesive regions [H(1), H(3)], ..., [H(m2-2), H(m2)].

[0103] This disclosure is not limited to the embodiments described above, and can be implemented in a variety of other ways. Therefore, these embodiments are merely illustrative in all respects and should not be constrained. The scope of this disclosure is defined by the claims and is not restricted by the text of the specification. Furthermore, any variations or modifications falling within the equivalent scope of the claims are all within the scope of this disclosure. [Explanation of symbols]

[0104] 1. Photosensitive drum (an example of an image carrier) 100 Image forming apparatus 3 Printheads 31 Light-emitting element 311 Light-emitting element panel (example of a substrate) 313 Lens holding member 316 Support member 32 lens array 410 Dispenser 411 Nozzles 420 Ultraviolet irradiation device 430 Caulking agent application device 440 Roller Crimping Device D1 First depth direction D2 Second depth direction F. UV-curing adhesive (an example of an adhesive) H Adhesive area (1st adhesive area, 2nd adhesive area) L Longitudinal direction M Width direction N Optical axis direction N1 One side N2 other side Q1 1st edge Q2 Second edge S Array Direction UV ultraviolet light W1 First curvature direction W2 Second curvature direction d1 1st size d2 2nd size e1 1st distance e2 2nd distance f1 Distance from the virtual center line f2 is the distance from the virtual center line. g Length in the longitudinal direction of the entire bonding area α Opposing area β Virtual Central Line

Claims

1. A print head comprising a substrate having a plurality of light-emitting elements arranged in a line, a long lens array that focuses the light emitted by the plurality of light-emitting elements onto an image carrier, and a long lens holding member that holds the lens array, In the opposing region where the lens array and the lens holding member face each other, the lens array and the lens holding member are bonded together by a plurality of bonding regions in the longitudinal direction. The print head is characterized in that the plurality of adhesive regions include a first adhesive region located on one side in the optical axis direction of the plurality of light-emitting elements, and a second adhesive region located on the other side in the optical axis direction.

2. A print head according to claim 1, A print head characterized in that the first adhesive region and the second adhesive region are alternately located in the longitudinal direction.

3. A print head according to claim 1, At least one of the lens holding member and the lens array is provided with a plurality of recesses for applying adhesive. The plurality of recesses include a first recess having a first depth for bonding in the first bonding region, and a second recess having a second depth for bonding in the second bonding region. The first recess and the second recess both have the same depth direction. A print head characterized in that the second depth of the second recess is deeper than the first depth of the first recess.

4. A print head according to claim 1, At least one of the lens holding member and the lens array is provided with a plurality of recesses for applying adhesive. The plurality of recesses include a first recess having a first depth for bonding in the first bonding region, and a second recess having a second depth for bonding in the second bonding region. The print head is characterized in that the first recess and the second recess have mutually different depth directions.

5. A print head according to claim 4, A print head characterized in that the first depth of the first recess and the second depth of the second recess are the same depth.

6. A print head according to claim 4, A print head characterized in that at least a portion of the first adhesive region and the second adhesive region overlap in the longitudinal direction.

7. A print head according to claim 1, A print head characterized in that the first size in the longitudinal direction of the first adhesive region is the same for all of them, the second size in the longitudinal direction of the second adhesive region is the same for all of them, and the first size and the second size are the same.

8. A print head according to claim 1, A print head characterized in that the number of first adhesive regions is the same in all cases, the number of second adhesive regions is the same in all cases, and the number of first adhesive regions and second adhesive regions are the same.

9. A print head according to claim 1, A print head characterized in that the first distance between adjacent first adhesive regions is the same in all cases.

10. A print head according to claim 1, A print head characterized in that the second distance between adjacent second adhesive regions is the same in all cases.

11. A print head according to claim 1, The first distance between adjacent first adhesive regions is the same, and the second distance between adjacent second adhesive regions is the same. A print head characterized in that the first distance and the second distance are the same.

12. A print head according to claim 1, A print head characterized in that the lens array and the lens holding member are bonded together at the first and second bonding regions on both sides in the short direction.

13. An image forming apparatus characterized by comprising a print head according to any one of claims 1 to 12.

Images