Print head and image forming apparatus

Abstract

To provide a print head including a film-like light emitting element panel having a plurality of light emitting elements arranged in a line shape and a lens array condensing light emitted from the plurality of light emitting elements on an image carrier, and to provide an image forming apparatus capable of easily performing relative position adjustment between the lens array and the plurality of light emitting elements.SOLUTION: A print head 3 provided with a film-like light emitting element panel 311 and a lens array 32 is provided with a panel holding member 314 for holding the light emitting element panel 311 and a lens holding member 313 for holding the lens array 32, the lens holding member 313 and the panel holding member 314 are formed as separate members, and a gap H is provided between the lens holding member 313 and the panel holding member 314.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present disclosure relates to printheads and image forming devices such as copiers, multifunction peripherals, printers, and facsimile machines. [Background technology]

[0002] A print head generally comprises an light-emitting element mounting member having a plurality of light-emitting elements arranged in a line, and a lens array that focuses the light emitted by the plurality of light-emitting elements onto an image carrier (e.g., a photosensitive drum).

[0003] For example, when a printed wiring board on which a light-emitting element array in which multiple light-emitting diodes (inorganic LEDs) are arranged in a linear fashion is used as the light-emitting element mounting member, the printed wiring board and the lens array are held by the same lens holding member (lens holding portion) (see, for example, Patent Document 1).

[0004] In such a print head, a printed wiring board having a plurality of light-emitting diodes is typically fixed to the lens holding member after adjusting the relative positions (e.g., focus adjustment) between the lens array and the plurality of light-emitting diodes by moving at least one of the lens array and the fixed lens holding member relative to each other. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-76584 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when a film-like light-emitting element panel having a plurality of light-emitting elements (e.g., organic EL) arranged in a line is used as the light-emitting element mounting member, the light-emitting element panel is formed in a film shape (it is flexible), so the light-emitting element panel will curve if left as is, making it difficult to adjust the relative positions (e.g., focus adjustment) between the lens array and the plurality of light-emitting elements.

[0007] Therefore, the present disclosure aims to provide a print head and an image forming apparatus that include a film-like light-emitting element panel having a plurality of light-emitting elements arranged in a line, and a lens array that focuses light emitted by the plurality of light-emitting elements onto an image carrier, and that allows easy adjustment of the relative positions of the lens array and the plurality of light-emitting elements. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the present disclosure provides a print head including a film-like light-emitting element panel having a plurality of light-emitting elements arranged in a line, and a lens array that focuses light emitted by the plurality of light-emitting elements onto an image carrier, the print head including a panel holding member that holds the light-emitting element panel, and a lens holding member that holds the lens array, the lens holding member and the panel holding member being separate members, and a gap larger than the thickness of the light-emitting element panel is provided between the lens holding member and the panel holding member.The present disclosure also provides an image forming apparatus including the print head according to the present disclosure. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to easily adjust the relative positions of the lens array and the plurality of light-emitting elements. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view showing an image forming apparatus according to an embodiment of the present invention. [Figure 2] 1 is a perspective view of an example of a print head provided on a main body frame in an image forming apparatus according to an embodiment of the present invention, viewed obliquely from above on the front side. [Figure 3] 3 is a perspective view of the print head shown in FIG. 2 supported on a mounting section, viewed obliquely from above on the front side. [Figure 4] FIG. 2 is a perspective view of the print head as seen from diagonally above the rear side. [Figure 5] FIG. 5 is a perspective view of the print head shown in FIG. 4, viewed obliquely from below on the front side. [Figure 6] 5 is an exploded perspective view of the print head shown in FIG. 4, viewed obliquely from above on the front side. FIG. [Figure 7] 5 is an exploded perspective view of the print head shown in FIG. 4, viewed obliquely from below on the rear side. FIG. [Figure 8] FIG. 2 is a cross-sectional perspective view of the print head as seen from diagonally above the front side. [Figure 9] FIG. 2 is a cross-sectional view of a print head. [Figure 10] FIG. 10 is a schematic diagram for easily understanding the cross-sectional view shown in FIG. [Figure 11] 1 is a plan view showing a state in which a flexible circuit board is extended linearly in a light-emitting element panel, a flexible circuit board, and a printed wiring board that constitute a print head. FIG. [Figure 12] FIG. 10 is a perspective view illustrating an example of a first step in the manufacturing process of the print head. [Figure 13] FIG. 10 is a perspective view illustrating an example of a second step in the manufacturing process of the print head. [Figure 14] FIG. 10 is a perspective view illustrating an example of a third step in the manufacturing process of the print head. [Figure 15] FIG. 10 is a perspective view illustrating an example of a fourth step in the manufacturing process of the print head. [Figure 16] FIG. 10 is a perspective view illustrating an example of a fifth step in the manufacturing process of the print head. [Figure 17] FIG. 10 is a perspective view illustrating an example of a sixth step in the manufacturing process of the print head. [Figure 18] FIG. 10 is a perspective view illustrating an example of a seventh step in the manufacturing process of the print head. [Figure 19] 10 is a perspective view schematically showing an adjustment direction of at least one of a lens holding member and a panel holding member. FIG. [Figure 20] 10 is a side view schematically showing an adjustment direction of at least one of a lens holding member and a panel holding member. FIG. [Figure 21] 10 is a side view showing an example of a configuration in which a R-shaped chamfered portion is provided in a lens holding member. FIG. [Figure 22] 10 is a side view showing an example of a configuration in which a rounded chamfered portion is provided in a panel holding member. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following description, the same components are denoted by the same reference numerals. The names and functions of the components are also the same. Therefore, detailed descriptions thereof will not be repeated.

[0012] (Image forming device) 1 is a cross-sectional view showing an image forming apparatus 100 according to this embodiment. In the figure, the rotational axis direction of the photosensitive drum 1 is designated as X, the front side as X1, the back side as X2, the direction perpendicular to the rotational 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 rotational axis direction X and the left-right direction Y as Z, in the following description.

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

[0014] In each of the image stations Pa, Pb, Pc, and Pd, the chargers 2-2 uniformly charge the surfaces 1a of the photosensitive drums 1-1, which are driven to rotate in a predetermined rotation direction R, to a predetermined potential. The print heads 3-3 expose the surfaces 1a of the photosensitive drums 1-1 to light, forming electrostatic latent images on the surfaces 1a of the photosensitive drums 1-1. The developing devices 4 develop the electrostatic latent images on the surfaces 1a of the photosensitive drums 1-1 to form toner images on the surfaces 1a of the photosensitive drums 1-1. This results in toner images of each color being formed on the surfaces 1a of the photosensitive drums 1-1. The drum cleaning devices 6-6 remove and collect residual toner from the surfaces 1a of the photosensitive drums 1-1. The primary transfer devices 5-5 sequentially transfer the toner images of each color on the surfaces 1a of the photosensitive drums 1-1, superimposed on one another, to an intermediate transfer belt 23, which is rotated by a drive roller 21 and a driven roller 22 of a belt drive device 20, forming color toner images on the intermediate transfer belt 23. The belt cleaning device 7 removes and collects residual toner from the intermediate transfer belt 23 .

[0015] A transfer nip portion TN is formed between the intermediate transfer belt 23 and a transfer roller 81 of the secondary transfer device 8. The transfer roller 81 of the secondary transfer device 8 sandwiches a sheet P, such as a recording paper, transported through the sheet transport path 11 in the transfer nip portion 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 fixes the color toner image on the sheet P by sandwiching the sheet P between a fixing member (fixing belt 91 in this example) and a pressure member (pressure roller 92 in this example) and applying heat and pressure to the sheet P.

[0016] The sheet P is drawn out of the paper feed cassette 13 by the pickup roller 12, transported through the sheet transport path 11, passed through the secondary transfer device 8 and the fixing device 9, and then transported to the discharge tray 15 via the discharge roller 14. The sheet transport path 11 is provided 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 the transfer of the toner image at the transfer nip portion TN between the intermediate transfer belt 23 and the transfer roller 81.

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

[0018] Fig. 8 is a cross-sectional perspective view of print head 3 viewed obliquely from above on the front side. Fig. 9 is a cross-sectional view of print head 3. Fig. 10 is a schematic diagram that clearly shows the cross-sectional view shown in Fig. 9. Fig. 11 is a plan view showing a state in which flexible circuit board 312a is extended linearly in light-emitting element panel 311, flexible circuit board 312a, and printed wiring board 312b that constitute print head 3.

[0019] In the following description, the plurality of light-emitting elements 31-31 in the print heads 3-3 will be described as organic light-emitting diodes (OLEDs: Organic Light-Emitting Diodes, hereinafter simply referred to as OLEDs). Note that the light-emitting elements 31-31 are not limited to OLEDs and may be inorganic light-emitting diodes (LEDs) or nano-scale light-emitting diodes (LEDs) that are smaller than a micrometer.

[0020] Since the print heads 3-3 etc. all have the same configuration, they are shown in a single drawing in FIGS. 3 to 11, and in the following description, the print heads 3-3 etc. will simply be referred to as print heads 3 etc.

[0021] The image forming apparatus 100 according to this embodiment includes a photosensitive drum 1 and a long print head 3. The print head 3 includes 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 FIGS. 9 to 11). The light-emitting elements 31-31 emit light for exposing the surface 1a of the photosensitive drum 1. The light-emitting elements 31-31 are arranged in a line in 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 reduce the size and cost of the print head 3.

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

[0023] The print head 3 is provided on the bridge section 210. The bridge section 210 is installed between the main body frames FL (in this example, between the main body frame FL1 on the front side X1 and the main body frame FL2 on the rear side X2) of the image forming apparatus main body 101 (see FIG. 1).

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

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

[0026] In this example, the driving member 312 includes a flexible circuit board 312a (connection cable member), a printed wiring board 312b (PWB: Printed Wiring Board) (connection board), a driving circuit element 312c, and a protective member 312d. One end of the connecting 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 connecting cable member 312a is a flexible circuit board (COF: Chip on Film) on which a driving 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 connecting cable member 312a has an input terminal 312b1 (see FIG. 10) (connector terminal) and is connected to a connector CN (see FIG. 10) via the input terminal 312b1. The protective member 312d protects the exposed portions of the light-emitting element panel 311 and the connecting cable member 312a. The connector CN is connected to an image processing device (not shown) provided in the image forming apparatus main body 101. As shown in Figures 9 and 10, the connector CN is provided inside (for example, vapor-deposited) so as not to protrude from the outer surface of the light-emitting element panel 311.

[0027] The lens holding member 313 is a frame-shaped member surrounding the outer peripheral surfaces 32a of the lens array 32 (see FIGS. 6 and 7) that are aligned along the optical axis direction N of the light-emitting elements 31. Here, the optical axis direction N is a direction (thickness direction) perpendicular to both the longitudinal direction L and width direction M of the print head 3. The width direction M is a direction perpendicular to the arrangement direction S of the linear arrangement of the plurality of light-emitting elements 31. The lens array 32 is inserted into an inner surface 313a of the frame-shaped lens holding member 313. At least a portion of the outer peripheral surfaces 32a (side surfaces 32a1, 32a1 along the longitudinal direction L in this example) of the lens array 32 is held by the lens holding member 313, and is bonded at least at some locations (multiple locations in this example) with an adhesive (e.g., an ultraviolet-curing adhesive). The periphery of 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 through the joint between the lens array 32 and the lens holding member 313 .

[0028] The panel holding member 314 is formed in a rectangular parallelepiped shape. A back surface of the light-emitting element panel 311, on which the light-emitting elements 31-31 are provided, opposite the light-emitting elements 31-31, is adhered to a surface 314a of the panel holding member 314 on the photosensitive drum 1 side (one side N1) in the optical axis direction N with an adhesive member E (e.g., double-sided adhesive tape) (see FIG. 10 ). A back surface 313c of the lens holding member 313 is fixed to a panel surface 311a of the light-emitting element panel 311 opposite the panel holding member 314. The periphery of 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 through the joint between the lens holding member 313 and the light-emitting element panel 311.

[0029] The main body member 315 has an arrangement portion 315a, a bending portion 315b, and a panel guide portion 315c. The arrangement portion 315a, the bending portion 315b, and the panel guide portion 315c are integrally formed.

[0030] The arrangement portion 315a arranges the panel holding member 314. The arrangement portion 315a is provided with an arrangement surface 315a1 on which the panel holding member 314 is arranged so that the back surface 314b of the panel holding member 314 on the side of the installation portion 210 comes into contact with the arrangement surface 315a1. This allows the panel holding member 314 to be reliably arranged on the arrangement surface 315a1 of the arrangement portion 315a. The arrangement surface 315a1 of the arrangement portion 315a is provided with a plurality (two) positioning protrusions or recesses (positioning protrusions 315a2, 315a2 in this example) (see FIG. 6). The back surface 314b of the panel holding member 314 is provided with positioning recesses or protrusions (positioning recesses 314c, 314c in this example) (see FIG. 7) that correspond to the plurality (two) positioning protrusions or recesses (315a2, 315a2). This allows the panel holding member 314 to be reliably positioned with respect to the main body member 315. The arrangement portion 315a is provided with a plurality of (two) holding portions 315a3 (see FIGS. 6, 7, and 9). The arrangement portion 315a and the holding portions 315a3 (315a3) are integrally formed. The holding portions 315a3 (315a3) detachably hold the panel holding member 314 to the arrangement portion 315a. The holding portions 315a3 (315a3) restrict movement of the panel holding member 314 toward the light emitting elements 31-31 (one side N1) in the optical axis direction N. The holding portions 315a3 (315a3) have locking portions 315a31 (see FIG. 9) that lock the surface 314a of the panel holding member 314.

[0031] Bending portion 315b is bent at an acute angle (for example, 60 degrees or less, about 50 degrees in this example) with respect to arrangement portion 315a. Printed wiring board 312b is fixed to surface 315b1 (inner surface) of bending portion 315b facing arrangement portion 315a. Input terminal 312b1 is provided at the end of printed wiring board 312b on the entrance side (opening SPa side) of space SP between arrangement portion 315a and bending portion 315b, and connector CN is connected facing toward space SP.

[0032] The panel guide portion 315c has a curved portion 315c1 that folds back the film-like protruding portion 317 from the support member 316 (314, 315) toward the space SP. The curved portion 315c1 is curved so that the lens holding member 313 side of the protruding portion 317 (between the light-emitting element panel 311 and the connection cable member (312a) in this example) is folded back at an angle of 180 degrees or more. The curved portion 315c1 protrudes beyond the lens holding member 313 to one of the one side M1 and the other side M2 ​​in the width direction M (the other side M2 ​​in this example). A panel portion 311b of the light-emitting element panel 311 on the connection cable member (312a) side and a portion of the connection cable member (312a) on the light-emitting element panel 311 side are bonded to the curved portion 315c1 with an adhesive member E. As a result, the curved portion 315c1 can reliably fold back the protruding portion 317 (the connection cable member (312a) in this example) into the space SP. The protective member 312d faces a portion of the protruding portion 317 that corresponds to the curved portion 315c1 and curves along the curved portion 315c1. As shown in FIGS. 6 and 7, the protective member 312d has a fastening member SC1 (male screw) inserted through the through-hole 312e1 of the holder 312e and the through-hole 312d1 of the protective member 312d on one side L1 in the longitudinal direction L, and is fastened to the fastened portion 315e (female screw) of the main body member 315. This allows the end of the protective member 312d on one side L1 in the longitudinal direction L to be fixed to the main body member 315.

[0033] Furthermore, the protective member 312d is fastened to the fastening portion 315e of the main body member 315 by inserting the fastening member SC1 through the through hole 312d1 of the protective member 312d on the other side L2 in the longitudinal direction L. This allows the end of the protective member 312d on the other side L2 in the longitudinal direction L to be fixed to the main body member 315. Furthermore, the printed wiring board 312b is positioned such that the positioning hole 312b2 of the printed wiring board 312b is matched with the positioning protrusion 315b2 of the bending portion 315b on the other side L2 in the longitudinal direction L. In this state, the printed wiring board 312b is fastened to the fastening portion 312e2 (female screw) of the holder 312e on one side L1 in the longitudinal direction L by inserting the fastening member SC2 through the through hole 315b3 of the bending portion 315b and the through recess 312b3 of the printed wiring board 312b. This allows the protective member 312d to be held in a state where it is positioned at the bent portion 315b.

[0034] The end of a part of the protruding portion 317 (connection cable member (312a)) provided in the space SP on the printed wiring board 312b side is folded back at the corner between the placement portion 315a and the bent portion 315b and connected to the printed wiring board 312b.

[0035] The drive circuit element 312c is provided on the arrangement portion 315a side of the connection cable member (312a). A recess 315a5 is provided on a 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 connection cable member (312a).

[0036] The main body member 315 is also provided with a pair of side plate portions 315f, 315g (see FIGS. 6 and 7) that close both ends in the longitudinal direction L of the space SP.

[0037] Next, a method for manufacturing the print head 3 will be described below with reference to FIGS.

[0038] 12 to 18 are perspective views respectively illustrating an example of the first to seventh steps of the manufacturing process for the print head 3. Note that Figs. 12 to 18 show the steps of providing the lens array 32 on the lens holding member 313, providing the light-emitting element panel 311 on the panel holding member 314, and providing the lens holding member 313 on the light-emitting element panel 311. Also, Figs. 19 and 20 are perspective and side views respectively that schematically show the adjustment direction of at least one of the lens holding member 313 and the panel holding member 314.

[0039] In the method of manufacturing the print head 3, first, as shown in FIG. 12, the lens array 32 is inserted into the inner surface (313a) of the lens holding member 313 (in this example, the through-hole 3131 extending in the vertical direction Z) (first step).

[0040] 13, a dispenser 410 is used to evenly apply ultraviolet curing adhesive F to multiple locations in the peripheral region (entire periphery) between the lens array 32 and the lens holding member 313, and then an ultraviolet irradiation device 420 is used to irradiate the ultraviolet curing adhesive F with ultraviolet rays UV to cure the ultraviolet curing adhesive F (second step). This allows the lens array 32 to be reliably held by the lens holding member 313.

[0041] 14, a caulking agent applicator 430 is used to apply elastic caulking agent G (elastic caulking resin) to the peripheral area (entire periphery) between the lens array 32 and the lens holding member 313 to seal the gap between the lens array 32 and the lens holding member 313 (third step). This makes it possible to prevent foreign matter such as dust from entering through the gap between the lens array 32 and the lens holding member 313.

[0042] Next, as shown in Figure 15, a roller pressing device 440 is used to attach the double-sided adhesive tape (E) (double-sided adhesive sheet) with a protective seal Ea attached to one side to the surface (314a) of the panel holding member 314 on which the light-emitting element panel 311 is to be attached (fourth step).

[0043] 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 to 31 in the light-emitting element panel 311 positioned at the reference positioning position of the panel holding member 314, the light-emitting element panel 311 is attached to the panel holding member 314 using a roller pressure-bonding device 440 (fifth step).

[0044] 17, the lens holding member 313 holding the lens array 32, which was produced in the third step (see FIG. 14), is placed on the light-emitting element panel 311 attached to the panel holding member 314, and a dispenser 410 is used to evenly apply ultraviolet curing adhesive F to at least four corners (the peripheral region or at least four corners) of the peripheral region (entire perimeter) between the lens holding member 313 and the panel holding member 314. After that, an ultraviolet irradiation device 420 is used to irradiate the ultraviolet curing adhesive F with ultraviolet rays UV to cure the ultraviolet curing adhesive F (sixth step). This allows the lens holding member 313 to be securely held by the panel holding member 314.

[0045] 18, a caulking agent applicator 430 is used to apply an elastic caulking agent G (elastic caulking resin) to the peripheral area (entire periphery) between the lens holding member 313 and the light-emitting element panel 311 to seal the gap H (see FIGS. 9, 10, and 17) between the lens holding member 313 and the light-emitting element panel 311 (seventh step). This makes it possible to prevent foreign matter such as dust from entering through the gap H between the lens holding member 313 and the light-emitting element panel 311.

[0046] (About this embodiment) As shown in Figures 9 to 11, the print head 3 of this embodiment includes a film-like light-emitting element panel 311 having a plurality of light-emitting elements 31-31 arranged in a line, and a lens array 32 that focuses light emitted by the plurality of light-emitting elements 31-31 onto a photosensitive drum 1 (an example of an image carrier).

[0047] (First embodiment) The print head 3 includes a panel holding member 314 that holds the light-emitting element panel 311, and a lens holding member 313 that holds the lens array 32. The panel holding member 314 and the lens holding member 313 are separate members, and a gap H that is larger than the thickness h1 (see FIG. 10) of the light-emitting element panel 311 is provided between the lens holding member 313 and the panel holding member 314. In this example, the gap H is larger than the dimension h obtained by adding the thickness h1 of the light-emitting element panel 311 to the thickness h2 (see FIG. 10) of the adhesive member E that adheres the light-emitting element panel 311 to the panel holding member 314. Here, a gap Ha (see FIGS. 9 and 10) is provided between the lens holding member 313 and the light-emitting element panel 311. This gap Ha is a space (a so-called adjustment margin) that allows for relative movement of at least one of the light-emitting element panel 311 and the lens holding member 313. For example, the gap H may be about 1 mm, the thickness of the light-emitting element panel 311 may be about 0.138 mm, and the thickness of the adhesive member E may be about 0.05 mm.

[0048] According to this embodiment, the light-emitting element panel 311, which is formed in a film-like shape (and is flexible), can be held by the panel holding member 314 (a rigid member) that is separate from the lens holding member 313, i.e., rigidity can be imparted to the light-emitting element panel 311. This facilitates relative movement of at least one of the film-like light-emitting element panel 311 having the plurality of light-emitting elements 31 and the lens holding member 313 to which the lens array 32 is fixed, thereby facilitating relative position adjustment between the lens array 32 and the plurality of light-emitting elements 31. The position adjustment process for the plurality of light-emitting elements 31 relative to the lens array 32 is performed between the fifth step (see FIG. 16) and the sixth step (see FIG. 17) of the aforementioned print head manufacturing process.

[0049] In the position adjustment step, at least one of the light emitting element panel 311 and the lens holding member 313 is moved relatively in the optical axis direction N of the light emitting elements 31-31, thereby making it possible to perform focus adjustment.

[0050] However, depending on the mounting dimensional accuracy of the lens array 32 to the lens holding member 313 and / or the mounting dimensional accuracy of the light-emitting element panel 311 to the panel holding member 314, and / or further, the shape accuracy of the lens holding member 313 and / or the shape accuracy of the panel holding member 314 (for example, a shape in which one surface in the optical axis direction N is inclined relative to the other surface in the arrangement direction S and / or width direction M), the quality of the image formed cannot be maintained by simply moving at least one of the light-emitting element panel 311 and the lens holding member 313 relatively in the optical axis direction N of the light-emitting elements 31-31.

[0051] Therefore, it is desirable to adjust the relative position in all directions by relatively moving at least one of the light-emitting element panel 311 and the lens holding member 313 in a direction other than the optical axis direction N (for example, the arrangement direction S, the width direction M, the first rotation direction U about the first rotation axis γ1 along the optical axis direction N, the second rotation directions Va and Vb about the second rotation axes γ2a and γ2b along the arrangement direction S, and the third rotation directions Wa and Wb about the third rotation axes γ3a and γ3b along the width direction M). Here, for example, in the arrangement direction S and the width direction M, the quality of the formed image can be maintained by controlling the timing of writing to the photosensitive drum 1 (control in the main scanning direction) and the timing of light emission of the light-emitting elements 31-31 (control in the sub-scanning direction). However, adding a timing control configuration increases costs.

[0052] In this regard, in the present embodiment, the panel holding member 314 and the lens holding member 313 are separate members, so that it is not only possible to relatively move at least one of the light-emitting element panel 311 and the lens holding member 313 in the optical axis direction N, but also possible to relatively move them in directions other than the optical axis direction N (for example, the arrangement direction S, the width direction M, the first rotation direction U, the second rotation directions Va and Vb, and the third rotation directions Wa and Wb), thereby adjusting the relative position in any direction. Furthermore, since there is no need to add a timing control configuration for the arrangement direction S and the width direction M, it is possible to keep costs low.

[0053] The relative positions of the multiple light-emitting elements 31 to 31 and the lens array 32 (for example, the optical axis direction N, the arrangement direction S, the width direction M, the first rotation direction U, the second rotation directions Va, Vb, and the third rotation directions Wa, Wb) are adjusted using a jig or the like during the production process.

[0054] (Second embodiment) 21 and 22 are side views showing an example of a configuration in which R-shaped chamfered portions 313g, 314g are provided in the lens holding member 313 and the panel holding member 314. Note that R-shaped chamfered portions 313g, 314g may be provided in both the lens holding member 313 and the panel holding member 314, or C-shaped chamfered portions 313g, 314g may be provided in the lens holding member 313 and / or the panel holding member 314, but these examples are not shown in the drawings.

[0055] At least one of the opposing surfaces 313f1, 314f1 between the lens holding member 313 and the panel holding member 314 (both opposing surfaces 313f1, 314f1 or opposing surface 313f1 or opposing surface 314f1) has a C-shaped or R-shaped chamfered portion 313g, 314g provided at the edge between at least one adjacent side surface (all or part of the adjacent side surfaces).

[0056] That is, when the lens holding member 313 is provided with the chamfered portion 313g, the C-shaped or R-shaped chamfered portion 313g is provided on the edge between at least one adjacent side surface on the surface 313f1 facing the panel holding member 314. When the panel holding member 314 is provided with the chamfered portion 314g, the C-shaped or R-shaped chamfered portion 314g is provided on the edge between at least one adjacent side surface on the surface 314f1 facing the lens holding member 313.

[0057] When the lens holding member 313 is provided with a C-shaped or R-shaped chamfered portion 313g, the edge portion of the lens holding member 313 where the chamfered portion 313g is provided is the edge portion between at least one of the side surfaces 313f2, 313f3 facing the arrangement direction S and the side surfaces 313f4, 313f5 facing the width direction M and the opposing surface 313f1.

[0058] When a C-shaped or R-shaped chamfered portion 314g is provided on the panel holding member 314, the edge portion on which the chamfered portion 314g of the panel holding member 314 is provided is the edge portion between at least one of the side surfaces 314f2, 314f3 facing the arrangement direction S and the side surfaces 314f4, 314f5 facing the width direction M and the opposing surface 314f1.

[0059] Here, the C-shaped surface is the shape of an inclined plane connected to the opposing surface (313f1 and / or 314f1), and the R-shaped surface is the shape of a convex curved surface connected to the opposing surface (313f1 and / or 314f1).

[0060] In this example, the lens holding member 313 and the panel holding member 314 are shaped so that five adjacent faces (313f1 to 313f5), (314f1 to 314f5) are orthogonal to each other.

[0061] (Third embodiment) In this embodiment, as shown in FIG. 17, a lens holding member 313 and a panel holding member 314 are bonded together with a gap H therebetween by an adhesive (ultraviolet curing adhesive F in this example).

[0062] This allows the lens holding member 313 to be reliably held by the panel holding member 314.

[0063] (Fourth embodiment) Incidentally, when lens holding member 313 and panel holding member 314 are sealed using a caulking agent that shrinks after hardening, there is a risk that the adjusted positions of lens array 32 and the plurality of light emitting elements 31 may become misaligned after adjustment.

[0064] In this regard, in this embodiment, the lens holding member 313 and the panel holding member 314 are sealed with an elastic caulking agent G as shown in FIG.

[0065] This makes it possible to prevent the elastic caulking agent G from shrinking after hardening, thereby effectively preventing deviation of the adjusted positions of the lens array 32 and the plurality of light-emitting elements 31-31 after adjustment.

[0066] Examples of the elastic caulking agent G include a liquid moisture-curing elastic adhesive that complies with the flame retardant standard UL94 V-0, and a flame-retardant elastic adhesive whose main component is a special polymer containing a silyl group.

[0067] The present disclosure is not limited to the above-described embodiments, but can be implemented in various other forms. Therefore, the embodiments are merely examples in all respects and should not be interpreted as being limiting. The scope of the present disclosure is defined by the claims and is not bound by the text of the specification. Furthermore, all modifications and variations within the equivalent scope of the claims are within the scope of the present disclosure. [Explanation of symbols]

[0068] 1. Photosensitive drum (an example of an image carrier) 1a surface 100 Image forming device 3 print head 31 Light-emitting element 311 Light-emitting element panel 313 Lens holding member 313f1 Opposite surface 313f2 side 313f3 side 313f4 Side 313f5 side 314 Panel holding member 314f1 Opposite surface 314f2 side 314f3 side 314f4 side 314f5 side 32 Lens Array 410 Dispenser 420 Ultraviolet irradiation device 430 Caulking agent application device 440 Roller pressure device F UV curing adhesive G Elastic caulking agent H gap Ha Gap h1 Thickness of the light-emitting element panel h2 Thickness of adhesive material L Longitudinal direction L1 One side L2 other side M Width direction M1 One side M2 Other side N Optical axis direction N1 One side N2 other side S array direction U First rotation direction V Second rotation direction W Third rotation direction X rotation axis direction Y left / right direction Z vertical direction γ1 First rotation axis γ2 Second rotation axis γ3 Third rotation axis

Claims

1. A print head comprising: a film-shaped light-emitting element panel having a plurality of light-emitting elements arranged in a line; and a lens array that focuses light emitted by the plurality of light-emitting elements onto an image carrier, a panel holding member that holds the light-emitting element panel; and a lens holding member that holds the lens array, The lens holding member and the panel holding member are separate members, A print head according to claim 1, wherein a gap larger than a thickness of said light-emitting element panel is provided between said lens holding member and said panel holding member.

2. 10. The printhead of claim 1, A print head characterized in that, on at least one of the opposing surfaces where the lens holding member and the panel holding member face each other, a C-shaped or R-shaped chamfered portion is provided on the edge between at least one adjacent side surface.

3. 10. The printhead of claim 1, The print head is characterized in that the lens holding member and the panel holding member are bonded together with an adhesive with the gap provided therebetween.

4. 10. The printhead of claim 1, The print head is characterized in that the lens holding member and the panel holding member are sealed with an elastic caulking agent.

5. An image forming apparatus comprising the print head according to any one of claims 1 to 4.

Images