JP4836714B2 - Optical printer head - Google Patents

Description

  The present invention relates to an optical printer head used as exposure means for an electrophotographic printer or the like.

  Conventionally, an optical printer head such as an LED array head has been used as exposure means for an electrophotographic printer or the like.

  As such a conventional optical printer head, as shown in FIG. 6, a head substrate 21 in which a plurality of light emitting element array chips 22 each having a plurality of light emitting elements arranged linearly in the main scanning direction are arranged in a line. The lens holder 24 has a rod lens array 23 attached thereto, and a base plate 25 on which the head substrate 21 is supported.

  A lens holder 24 is disposed above the head substrate 21, and a base plate 25 is disposed below the head substrate 21. The head substrate 21, lens holder 24, and base plate 25 are, for example, U-shaped in cross section. In this structure, the lens holder 24 and the base plate 25 are enclosed and held by the outer clip 26.

  Such an optical print head 30 selectively causes the light emitting elements provided on the upper surface of the light emitting element array chip 22 to individually emit light based on image data supplied from the outside, and the rod lens array 23. To supply outside.

The optical print head 30 is incorporated in a copying apparatus or a printing apparatus, and irradiates the photosensitive drum P with light from the optical printer head 30 so as to face the photosensitive drum P, whereby a predetermined latent image is obtained. Is formed. The latent image formed on the photosensitive drum P is then converted into a toner image through a process such as development, and a predetermined image is recorded on the recording paper by transferring and fixing the toner image on the recording paper.
JP 2003-341134 A

  However, in the conventional optical printer head 30 described above, since the lens holder 24 and the base plate 25 are held by being clamped from the outside by the U-shaped clip 26, there is a problem that the overall structure is increased in size.

  Further, since the U-shaped clip 26 has a U-shaped cross section, when the optical printer head 30 is assembled, the lens holder 24 and the base plate 25 are placed in the U-shaped clip 26 with the U-shaped clip 26 opened. It is necessary to perform a complicated operation such as fitting and locking the end of the U-shaped clip 26 to a predetermined position of the lens holder 24, which causes a decrease in productivity.

  According to the present invention, a head substrate in which a plurality of light emitting elements are arranged on one side in a housing having a lens attached to the upper side, a base plate that supports the head substrate from the other side, and the base plate as the head substrate. And a leaf spring that is pressed to the side and has both ends locked to the housing from the inner surface side of the housing.

  Further, a plurality of the leaf springs are provided in the arrangement direction of the light emitting elements, and the pressing force of the leaf springs against the base plate is larger in the central area than both end areas in the arrangement direction of the light emitting elements. It is a feature.

  Further, the housing has a pair of side wall portions extending along the arrangement direction of the light emitting elements, and both end portions of the leaf spring are locked to the side wall portions.

  Further, an annular spacer surrounding the light emitting element is interposed between an upper inner surface of the housing to which the lens is attached and one surface of the head substrate.

  Further, a through hole is provided in a corresponding portion of the head substrate and the base plate, and a protrusion provided on the annular spacer is inserted into the through hole so as to penetrate the head substrate and the base plate. Is.

  As described above, according to the optical printer head of the present invention, since the fixing leaf spring is accommodated in the housing, the overall structure can be reduced in size. Since the base plate disposed in the housing can be easily assembled simply by pressing the base plate from below with a leaf spring and locking a part of the leaf spring to the housing, workability and productivity are improved.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  1 is a longitudinal sectional view of an optical printer head according to an embodiment of the present invention, FIG. 2 is an upper perspective view of the optical printer head of FIG. 1, and FIG. 3 is a lower perspective view of the optical printer head of FIG. FIG. 4 is an exploded perspective view of the optical printer head of FIG.

  In each figure, reference numeral 1 is a head substrate, 2 is a light emitting element array chip, 3 is a rod lens array, 4 is a housing, 5 is a base plate, 6 is a leaf spring, 7 is an insulating double-sided adhesive tape, and 8 is an annular spacer. .

  The head substrate 1 has an elongated shape, and a plurality of light emitting element array chips 2 are attached to the upper surface of the head substrate 1, and the light emitting element array chips 2 are arranged in the main scanning direction. The head substrate 1 is manufactured by impregnating and curing a liquid epoxy resin on a glass cloth base formed using, for example, glass yarn, and cutting it into a long shape having a predetermined dimension.

  The housing 4 has an upper inner surface 4a extending in the arrangement direction of the light emitting elements and a pair of side wall portions 4b orthogonal to the upper inner surface 4a, and has a substantially U-shaped cross section as a whole. is there. The rod lens array 3 is bonded and fixed to the upper inner surface 4a, and the rod lens array 3 and the light emitting element array chip 2 face each other. The main body of the housing 4 is formed by pressing a metal flat plate material such as an aluminum die cast or surface galvanized iron material, aluminum, or SUS.

  The base plate 5 is for supporting the head substrate 1 and is made of, for example, a surface galvanized iron material, aluminum, or a metal material such as SUS.

  The light emitting element array chip 2 has a large number of light emitting elements arranged along the main scanning direction at a dot density of 600 dpi, for example, and emits light with a predetermined luminance when power is applied. As the light emitting element, for example, a GaAlAs-based or GaAsP-based 20 μm square light emitting diode is preferably used. The light emitting element array chip 2 having such a light emitting diode is epitaxially grown on the upper surface of a single crystal silicon wafer by using a conventionally known semiconductor manufacturing technique, specifically, MOCVD (Metal Organic Chemical Vapor Deposition) method or the like. It is formed by letting. In the light emitting element array chip 2, the wiring pattern of the electrodes and the head substrate 1 is bonded with a thin metal wire or the like. The width of the light emitting elements (main scanning direction) is set to a width dimension corresponding to, for example, 20 to 70% of the arrangement pitch of the light emitting elements constituting the column, and when this causes adjacent light emitting elements to emit light simultaneously. In addition, it is possible to ensure an appropriate overlap between the beams irradiated to the photosensitive member p.

  The rod lens array 3 is for irradiating and imaging light of a light emitting element of the light emitting element array chip 2 on a photosensitive member p described later at an equal magnification, and a plurality of fiber lenses made of glass or plastic are arranged. In addition, the housing 4 holds the light emitting element array chip 2 directly above.

  On the other hand, a photoconductor p is provided so as to face the optical printer head 30 and is arranged substantially parallel to the arrangement of the light emitting elements. The photoreceptor p has a structure in which a photoconductive layer made of amorphous silicon or the like is attached to the outer surface of a cylindrical base made of aluminum or the like, and light from the light emitting element of the optical printer head 30 is applied to the photoconductive layer. When irradiated, the specific resistance of the photoconductive layer is rapidly reduced to form a predetermined latent image corresponding to the image data.

  According to the present invention, a head substrate 1 in which a plurality of light emitting elements are arranged on one side in a housing 4 having a lens attached to the upper side, a base plate 5 that supports the head substrate 1 from the other side, and the base plate It is important to include a leaf spring 6 that presses the head 5 toward the head substrate 1 and has both ends locked to the housing 4 from the inner surface side of the housing 4. The head substrate 1 and the base plate 5 are accommodated in the housing 4, and a plurality of leaf springs are provided in a plurality of recesses or holes 4 c provided on both side wall portions 4 b of the housing 4 along the main scanning direction of the base plate 5. 6 is arranged.

The leaf spring 6 presses the base plate 5, and both ends of the leaf spring 6 have a shape that can be engaged with the recess or hole 4 c of the housing 4. For example, the leaf spring 6 includes a fixed portion 6a and a pressing force generating portion 6b. The pressing force generating portion 6b has a shape in which a flat plate material is curved convexly toward the upper surface. Such a fixed portion 6 a of the leaf spring 6 is locked in a plurality of concave portions or holes 4 c, and the pressing force generating portion 6 b of the plate panel 6 is brought into contact with the lower surface side of the main surface of the base plate 5. , And has a function of pressing upward (on the base plate 5 side), and various shapes are assumed as shown in FIGS. The pressing force of the leaf spring 6 is preferably set to a relatively ^high value of 55 N / cm ² to 120 N / cm ^2. For example, a flat plate material made of stainless steel or the like is formed by sheet metal pressing.

  As described above, when the optical printer head 30 is assembled, the plate spring 6 is pushed into the housing 4, and the fixing portion 6a of the plate spring 6 is simply engaged with the concave portion and the hole 4c of the housing 4, so that the assembly can be easily performed. it can.

  Further, a plurality of the leaf springs 6 are provided in the arrangement direction of the light emitting elements, and the pressing force of the leaf springs 6 against the base plate 5 is larger in the central area than both end areas in the arrangement direction of the light emitting elements. Preferably it is.

  Accordingly, when a downward warp occurs due to the weight of the base plate 5 in the central region of the base plate 5, the deviation of the conjugate length Tc in the central region of the base plate 5 can be easily adjusted / corrected. Further, the pressing force of the leaf spring 6 in the central region and both end regions can be freely adjusted according to the warp of the base plate 5 by preparing the pressing force generating portion 6b with different angles and widths. I can do it.

  Furthermore, it is preferable that the housing 4 has a pair of side wall portions extending along the arrangement direction of the light emitting elements, and the fixing portion 6a of the leaf spring 6 is locked in the concave portion or the hole portion 4c.

  Thereby, since the leaf | plate spring 6 is arrange | positioned inside, without exposing to the exterior of the housing 4, it can reduce in size as a whole structure.

  Further, it is preferable that an annular spacer 8 surrounding the light emitting element is interposed between the upper inner surface 4 a of the housing 4 and one surface of the head substrate 1.

  The annular spacer 8 surrounds at least the light emitting diode array 2 on the head substrate 1 and has a hole 8a penetrating in the thickness direction. The positional relationship between the upper inner surface 4a of the housing 4 and the head substrate 1 is determined by the annular spacer. Control only with thickness of 8. Thereby, the deviation of the conjugate length Tc can be easily adjusted / corrected, and can be attached even if the thickness of the annular spacer 8 is slightly changed. The annular spacer 8 is made of an insulating resin material such as polycarbonate or liquid crystal polymer.

  Further, a through hole 29 is provided at a corresponding portion of the head substrate 1 and the base plate 5, and the annular spacer 8 is provided in the through hole 29 so as to penetrate the head substrate 1 and the base plate 5 in the through hole 29. It is preferable that the protruding portion 28 is inserted.

  By providing the projecting portion 28 on the annular spacer 8, the positions of the head substrate 1 and the base plate 5 in the housing 4 are stabilized, and the head substrate 1 and the base plate 5 are displaced in the plane direction (direction perpendicular to the optical axis). Can be effectively suppressed. As a result, the protrusion 28 of the annular spacer 8 serves as a reference for positioning the housing 4, the head substrate 1, and the base plate 5. This positioning improves assembly workability and enables high-precision assembly.

  The present invention is not limited to the above-described embodiment, and various modifications and improvements can be made without departing from the gist of the present invention. In the above-described embodiment, the LED head has been described as an example. The present invention can also be applied to other optical printer heads, such as EL heads, plasma dot heads, liquid crystal shutter heads, fluorescent heads, and PLZTs.

It is a longitudinal cross-sectional view of the optical printer head of this invention. FIG. 3 is a top perspective view of the optical printer head of the present invention. 2 is a lower perspective view of the optical printer head of the present invention. FIG. It is a disassembled perspective view of the optical printer head of this invention. (A)-(d) is a 3rd view of each embodiment of the leaf | plate spring in this invention. It is sectional drawing of the conventional optical printer head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Head substrate 2 ... Light emitting element array chip 3 ... Rod lens array 4 ... Housing 4a ... Upper surface 4b ... Side wall part 4c ... Recess and hole 5 ... Base plate 6 .. Leaf spring 6a .. Fixing portion 6b .. Pressing force generating portion 7 .. Insulating double-sided adhesive tape 8... Ring spacer 8a .. Hole portion 21 .. Head substrate 22. · · Rod lens array 24 · · Lens holder 25 · · Base plate 26 · · U-shaped clip 27 · · Insulating double-sided adhesive tape 28 · · projection 29 · · through hole 30 · · optical printer head p · · · photosensitive body

Claims (5)

A head substrate in which a plurality of light emitting elements are arranged on one side in a housing with a lens attached to the top;
A base plate that supports the head substrate from the other side;
An optical printer head comprising a leaf spring that presses the base plate toward the head substrate and has both ends locked to the housing from the inner surface side of the housing. A plurality of the leaf springs are provided in the arrangement direction of the light emitting elements,
2. The optical printer head according to claim 1, wherein a pressing force of the plate spring against the base plate is larger in a central region than both end regions in the arrangement direction of the light emitting elements. The said housing has a pair of side wall part extended along the sequence direction of the said light emitting element, and the both ends of the said leaf | plate spring are latched by this side wall part, The Claim 1 or 2 characterized by the above-mentioned. Optical printer head. 4. An annular spacer surrounding the light emitting element is interposed between an upper inner surface of the housing to which the lens is attached and one surface of the head substrate. Optical printer head. A through hole is provided in a corresponding portion of the head substrate and the base plate, and a protrusion provided on the annular spacer is inserted into the through hole so as to penetrate the head substrate and the base plate. Item 5. The optical printer head according to Item 4.

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