JP2009119677A - Manufacturing method of led print head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an LED print head which maintains the linearity of an imaging line even if the wall of a base with an LED substrate fixed to a top surface is thinned, and also achieves miniaturization. <P>SOLUTION: Deflection in the longitudinal direction at the bottom surface of the base 4 is measured at least on three points which include both ends and the center of the base 4, thereby obtaining a projection amount of the center to both ends or respective projection amounts of both ends to the center. At the time of placing the base 4 on a flat surface for fixing a housing 5 to the base 4, if the both ends project rather than the center, a plate-shaped member 25 of the same thickness as an average value of projection amounts of both ends to the center is set at the center of the bottom surface of the base 4. Thereafter, the housing 5 is fixed while being pressed against the top surface of the base 4. By this configuration, the imaging line can be kept straight even if the wall of the base 4 is thinned. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an LED print head used in an image forming apparatus such as a copying machine or a printer.

  Conventionally, in order to form an electrostatic latent image of an image on an electrostatic latent image carrier such as a photosensitive drum of an image forming apparatus, an LED print head having an LED array and a lens array as main components has been used. Yes.

  The LED print head includes a long LED substrate on which a plurality of LED arrays are arranged in a straight line or a staggered pattern, a long base to which the LED substrate is fixed, and a long housing fixed to the base. And a long lens array fixed to the housing opposite the LED array (see, for example, Patent Documents 1 to 4).

  In order to form an electrostatic latent image on the surface of the photosensitive drum with high accuracy, the LED print head needs to minimize variations in image forming points. Here, the imaging point refers to a point (focal point) where light emitted from a plurality of light emitting points (LEDs) formed on the LED array converges through the lens array.

A means generally employed to reduce the variation in the image forming points is to make the flatness and straightness of the base for fixing the LED substrate highly accurate.
Therefore, the LED print head described in Patent Document 1 and Patent Document 2 employs means for integrally forming a base and a rigid body.
Further, the LED print heads described in Patent Documents 3 and 4 employ means for increasing the height of the base in the optical axis direction.

JP 2006-289843 A JP 2005-193638 A JP 2000-141744 A Japanese Patent Laid-Open No. 11-266037

  However, the above-described conventional LED print head needs to increase the processing accuracy and assembly accuracy of the base and other parts in order to reduce the variation of the image formation point, which increases the cost of the LED print head. There is a problem of doing.

  Further, in the conventional LED print head, in order to maintain the flatness and straightness of the base with high accuracy and ensure rigidity, the height of the base is increased (the thickness of the base is increased). This is because if the height of the base is made low (the thickness of the base is made thin), there is a problem that the imaging line formed by the plurality of light emitting points passing through the lens array is bent due to its own weight (for example, Japanese Patent Laid-Open 08-164631 etc.). For this reason, the conventional LED print head has a high height in the optical axis direction of the LED print head, so that not only can the size not be reduced, but also the cost of the base becomes high, and thus the cost of the LED print head increases. There was a problem.

  The present invention has been made to solve such a problem. An imaging line in which a plurality of light emitting points are formed through a lens array even if the height of the base is reduced (the thickness of the base is reduced). An object of the present invention is to provide an inexpensive LED print head manufacturing method that maintains linearity and achieves downsizing.

(First invention)
According to the first aspect of the present invention, there is provided an LED print head for fixing a housing in which a lens array is fixed to a base in which an LED substrate having a plurality of LED arrays is fixed on an upper surface so that the lens array faces the LED substrate. It is about the method.

  First, the base is placed on a measuring device that can measure the warpage of the lower surface of the base. And the curvature of the longitudinal direction in the lower surface of a base is measured by at least 3 points | pieces including the both ends and center part of a base. Thereby, it is possible to obtain (measure) the amount of protrusion of the central portion with respect to both end portions, or the amount of protrusion of each end portion with respect to the central portion, and (1) whether the lower surface of the base is convex in the central portion (2 ) It can be seen whether both ends are convex (the central part is concave).

  In making this measurement, it is desirable to support the vicinity of positioning pins attached to both ends of the base in order to position the LED print head with respect to the image forming apparatus. This is because it is possible to cause warpage due to the weight of the base that is actually generated when positioning the image forming apparatus.

Then, when the base is placed on a flat surface in order to attach the housing to the base, it is divided into the following two types according to the warp (1) or (2) of the lower surface of the base.
<In the case of (1)> When the central portion of the base lower surface protrudes from both ends, that is, when the central portion is convex, a plate-like member having the same thickness as the protruding amount of the central portion is used. Put on both ends.
<In the case of (2)> When both ends of the lower surface of the base protrude from the center, that is, when both ends are more convex than the center, the same thickness as the average value of the measured protrusions at both ends The plate-like member is placed at the center of the lower surface of the base.

  Here, the plate-like member is desirably a high-precision shim (liner) used when adjusting the position of the two members, that is, scissors. This is because the base can be supported by filling a part of the gap between the flat surface and the lower surface of the base with low cost and high accuracy.

  Thereafter, the housing is fixed to the upper surface of the base while being pressed. For example, when the housing is bonded and fixed using a UV adhesive, the UV adhesive is applied to a portion where the housing contacts the base at a plurality of locations while the pressing to the upper surface of the base of the housing is continued. The agent is solidified by irradiating it with ultraviolet rays.

  Even if the height of the base is lowered, in other words, the thickness of the base in the vertical direction is reduced by the method of manufacturing the LED print head, a plurality of light emission is not affected by the warp of the lower surface of the base. The housing can be fixed to the base so that the imaging lines formed by the points through the lens array are straight.

In other words, if there is a gap between the flat surface and the lower surface of the base, when the housing is pressed and fixed to the upper surface of the base, there is no gap between the flat surface and the lower surface of the base due to the pressing force of the housing, and the lower surface of the base adheres to the flat surface. To do. After the housing is fixed to the base, if the pressing force of the housing is removed, the base tries to return to the original state, so that the upper surface (and the housing) of the base is warped.
However, since the gap does not bend due to the pressing force of the housing even if the housing is pressed against the upper surface of the base by supplementing the gap with a plate-like member having a thickness corresponding to the warp generated on the lower surface of the base, As a result, the upper surface (and housing) of the base is not warped.

  For this reason, the linearity of each light emitting point of the LED array mounted on the LED substrate fixed to the upper surface of the base is maintained, so that the light emitted from each light emitting point passes through the lens array. Linearity is maintained.

(Second invention)
The first invention described above can be applied when the flatness of the upper surface of the base is high and the lower surface of the base has warpage. Conversely, the flatness of the lower surface of the base is high and the upper surface of the base is warped. In the case of having, the following second invention can be applied.

  That is, first, by measuring the warpage in the longitudinal direction on the upper surface of the base at at least three points including both ends and the center of the base, the amount of protrusion of the center with respect to both ends, or the protrusion of each of the ends with respect to the center Determine (measure) the quantity.

  In making this measurement, it is desirable to support the vicinity of positioning pins attached to both ends of the base in order to position the LED print head with respect to the image forming apparatus. This is because it is possible to cause warping of the base that occurs when positioning is actually performed with respect to the image forming apparatus.

Then, when the base is placed on a flat surface in order to attach the housing to the base, it is divided into the following two types according to the warp of the upper surface of the base.
(1) When both ends of the base protrude beyond the center of the base, a plate-like member having a thickness that is half the average value of the protrusions at both ends with respect to the center is placed at the center of the lower surface of the base. .
(2) When the center part of the base protrudes from both end parts of the base, plate-like members having a thickness that is half the protrusion amount of the center part with respect to both end parts are placed on both end parts of the lower surface of the base.

  Thereafter, the housing is fixed to the upper surface of the base while being pressed. For example, when the housing is bonded and fixed using an adhesive, the housing waits for the adhesive to solidify while continuing to be pressed against the upper surface of the base of the housing.

  Even if the height of the base is lowered, in other words, even if the thickness of the base in the vertical direction is reduced, the housing is fixed to the base so as to cancel the warping of the upper surface of the base. be able to.

  That is, when both ends of the base protrude beyond the center of the base, a plate-like member having a thickness that is half the average value of the protrusions of both ends relative to the center is placed at the center of the lower surface of the base. When the housing is pressed against the upper surface of the base in this state, the lower surface of the base is warped so that the central portion is concave (both ends of the lower surface of the base are convex).

  When the housing is fixed to the upper surface of the base while maintaining the pressure on the upper surface of the base of the housing, the base tends to return when the pressing force of the housing is removed.

  Therefore, the warped lower surface of the base becomes a flat surface, and the housing and the lens array slightly warp so that the light emitted from each light emitting point passes through the lens array and the image forming line is a straight line.

(Third invention)
Further, according to the present invention, the linearity of the imaging line can be made more accurate by measuring the warpage of the upper surface of the base with reference to the LED array of the LED substrate fixed to the upper surface of the base.

  That is, by measuring the warpage in the longitudinal direction on the upper surface of the base at at least three points including the upper surface of the LED array at both ends of the LED substrate and the upper surface of the LED array at the central portion, the protrusion of the central portion with respect to the both ends. The amount of protrusion of each of the both ends with respect to the amount or the center portion is obtained.

  In making this measurement, it is desirable to support the vicinity of positioning pins attached to both ends of the base in order to position the LED print head with respect to the image forming apparatus. This is because it is possible to cause a warp due to the weight of the base itself that is actually generated when positioning with respect to the image forming apparatus.

Then, when the base is placed on a flat surface such as a surface plate in order to attach the housing to the base, it is divided into the following two types according to the warpage of the upper surface of the base.
(1) When the upper surface of the LED array at both ends of the base protrudes from the upper surface of the LED array at the center of the base, the amount of protrusion of the upper surface of the LED array at both ends with respect to the upper surface of the LED array at the center A plate-like member having a thickness that is half the average value is placed in the center of the lower surface of the base.
(2) When the upper surface of the LED array at the center of the base protrudes from the upper surface of the LED array at both ends of the base, the amount of protrusion of the upper surface of the LED array at the center with respect to the upper surface of the LED array at both ends Half-thick plate members are placed on both ends of the lower surface of the base.

  Thereafter, the housing is fixed to the upper surface of the base while being pressed. For example, when the housing is bonded and fixed using an adhesive, the housing waits for the adhesive to solidify while continuing to be pressed against the upper surface of the base of the housing.

  With this LED print head manufacturing method, the warping of the base is grasped at the upper surface position of the LED array, so that the linearity of the plurality of LED arrays can be made more accurate, and as a result, the linearity of the imaging line Can be made more accurate.

(Fourth invention)
In the present invention, the positioning pins for positioning the LED print head with respect to the image forming apparatus may be attached to both ends of the base.

  With this configuration, the LED print head can be easily positioned with respect to the image forming apparatus.

(Fifth invention)
Further, when measuring the warpage in the longitudinal direction on the lower surface or the upper surface of the base, it is preferable to support the base in the vicinity of both ends of the base.

  With this configuration, the warp of the base is measured at the mounting positions of the positioning pins (both ends of the base) that serve as a reference for actually positioning the LED print head with respect to the actual machine (image forming apparatus). Even if it exists, there exists an effect that the highly accurate linearity of an imaging line can be maintained.

  According to the present invention, the height of the base can be reduced (the thickness of the base in the direction of the optical axis can be reduced), so that the base can be reduced in size and cost, and the LED print head can be reduced in size and cost. can do. Further, the linearity of the imaging line formed by each light emitting point through the lens array can be maintained with high accuracy.

  Hereinafter, the present invention will be described in detail using examples.

A first embodiment according to the present invention will be described with reference to FIGS.
1 is a plan view of an LED print head according to the present invention, FIG. 2 is a front view of the LED print head according to the present invention, FIG. 3 is an enlarged view of a side surface of the LED print head according to the present invention, and FIG. FIG. 5 is a schematic view (front view) showing a measurement state of the warp of the base, FIGS. 6 and 7 are front views showing an assembly state of the LED print head, FIG. Is a front view of the LED print head, FIG. 9 is a front view of the base, FIG. 10 is a front view of the plate member, FIGS. 11 and 12 are front views showing the assembled state of the LED print head, and FIG. FIG.

  The deflection amount of the LED print head, base, etc. is about several tens of μm. However, in order to make the explanation easy to understand, in FIG. 5 to FIG. Yes.

(LED print head)
As shown in FIGS. 1 to 3, an LED print head 1 according to the present invention includes a plurality of LED arrays 2 having a plurality of light emitting points (LEDs) (not shown) and a long length on which the plurality of LED arrays 2 are mounted. An LED substrate 3, an aluminum long base 4 to which the LED substrate 3 is fixed by an adhesive, a plastic long housing 5 fixed to the base 4 by an adhesive, an LED array 2, Oppositely, the lens array 6 is fixed to the housing 5 with an adhesive.

(Imaging line)
The LED print head 1 described above can measure a plurality of image forming points (focal points) using a measuring device described in, for example, Japanese Patent Application Laid-Open Nos. 2006-289789 and 2006-289790.

  Here, as shown in FIG. 4, the imaging point (focal point) means that when the light emitting point (LED) 10 of the LED array 2 is caused to emit light, the light emitted from the light emitting point 10 is converged by the lens array 6 ( A point (position) where light is condensed. That is, the conjugate length TC of the lens array 6 is the distance from the light emitting point 10 to the focal position 11.

  The conjugate length TC is a length L from the upper surface of the lens array 6 to the focal position (condensing position), and a focal position (from the lower surface of the lens array 1) where T is the height of the lens array 6 in the optical axis direction. Since the length L to the light emission position) is equal, the relationship TC = T + 2L is established.

(Conventional problem)
In the first embodiment, a case will be described in which the center portion of the lower surface of the base is warped so as to be a recess, and the flatness of the upper surface of the base is high.
As shown in FIG. 6, when the lower surface of the central portion of the base 4 is a concave portion (the lower surfaces of both end portions of the base 4 are convex portions), the base 4 is placed on a flat surface 24 formed on the upper surface of the surface plate 23. When placed, a gap is formed between the lower surface of the central portion of the base 4 and the flat surface 24.

Therefore, when the housing 5 to which the lens array 6 is attached is pressed against the upper surface of the base 4, the gap is eliminated as shown in FIG. 7. Instead, there is a gap between the lower surface of the housing 5 and the upper surface of the base 4. it can. When the housing 5 and the base 4 are fixed with an adhesive (not shown) while maintaining this state, the gap formed between the lower surface of the housing 5 and the upper surface of the base 4 is maintained as shown in FIG. Therefore, there arises a problem that the housing 5 and the lens array 6 are warped and the imaging line 9 is bent.
The housing 5 is fixed to the base 4 by applying an adhesive to the boundary between the housing 5 and the base 4 and solidifying it. In FIG. 7 and FIG. The agent is not shown.

(Measurement of warpage)
In order to solve the above-described problems, both ends in the longitudinal direction of the base 4 are placed on the support column 22 of the warp measuring device 20 as shown in FIG. Then, the warpage of the upper surface and the lower surface of the base 4 is measured by the non-contact type distance measuring sensors 21 respectively attached to the upper and lower sides of the warpage measuring device 20.

  In the first embodiment, three distance measuring sensors 21 are arranged on the center portion and both upper and lower surfaces of the base 4 respectively, so that the protrusion amounts of the upper and lower surfaces at the center portion and both end portions of the base 4 are measured. can do.

  That is, as shown in FIG. 9, on the lower surface of the base 4, the protrusion amounts A and B of the both ends of the base 4 with respect to the center can be obtained. Then, as shown in FIG. 10, it is possible to select a plate-like member 25 having an average value of the protruding amount, that is, C = (A + B) / 2.

(Attaching the housing to the base)
Thereafter, as shown in FIG. 11, when the base 4 is placed on the flat surface 24 of the surface plate 23 in order to attach the housing 5 to the base 4, the plate-like member 25 is interposed between the lower surface of the center portion of the base 4 and the flat surface 24. Put.

  Then, as shown in FIG. 12, even if the housing 5 is pressed against the upper surface of the base 4, the base 4 does not warp due to the pressing force of the base 4. Even after bonding and fixing, the housing 5 and the lens array 6 do not warp, and the imaging line 9 can be made straight.

  As described above, according to the present invention, it is possible to reduce the cost of the base 4 by reducing the height of the base 4 in the vertical direction, that is, the thickness of the base 4. As a result, the cost of the LED print head 1 can be reduced. be able to. And the linearity of the imaging line which each light emission point forms through a lens array can be made highly accurate.

A second embodiment according to the present invention will be described with reference to FIGS.
FIG. 14 is a schematic view (front view) showing a measurement state of warping of the base, FIGS. 15 and 16 are front views showing an assembled state of the LED print head, FIG. 17 is a front view of the LED print head, FIG. Is a front view of the base, FIG. 19 is a front view of the plate-like member, FIGS. 20 and 21 are front views showing the assembled state of the LED print head, and FIG. 22 is a front view of the LED print head.

The deflection amount of the LED print head, base, etc. is about several tens of μm. However, in order to make the explanation easy to understand, in FIG. 14 to FIG. Yes.
Further, only differences from the first embodiment will be described, and the same parts as those of the first embodiment will be denoted by the same reference numerals and description thereof will be omitted.

  The main difference between the second embodiment and the first embodiment is that the central portion of the lower surface of the base is warped so as to be a convex portion, and the flatness of the upper surface of the base is high.

(Conventional problem)
As shown in FIG. 15, when the central portion of the lower surface of the base 4 is a convex portion (both ends of the lower surface of the base 4 are concave portions), the base 4 is placed on the flat surface 24 formed on the upper surface of the surface plate 23. When placed, a gap is formed between both ends of the lower surface of the base 4 and the flat surface 24.

  Therefore, when the housing 5 to which the lens array 6 is attached is pressed against the upper surface of the base 4, the gap is eliminated and the upper surface of the base 4 is warped as shown in FIG. 16. Then, when the pressure applied to the base 4 of the housing 5 is continued until the adhesive applied to the boundary portion between the housing 5 and the base 4 is solidified, and the pressure is released, the base 4 returns to the original state as shown in FIG. As it tries to return, the housing 5 and the lens array 6 are warped, causing a problem that the imaging line 9 is bent.

  In FIG. 16, the central portion of the housing 5 is crushed, but it is not actually crushed, and the central portion of the housing 5 is opened. That is, since the cross section of the housing 5 has a shape as shown in FIG. 3, when the upper surface of the housing 5 is pressed, the thickness of the base 4 is thin and the bottom surface of the base 4 is a convex portion. Only the central part is displaced outward, that is, only the central part opens outward.

Therefore, in order to ensure the linearity of the imaging line of the LED print head, it is necessary to take measures to solve the above problems when the housing 5 is attached to the base 4.
(Measurement of warpage)
First, as shown in FIG. 14, both ends in the longitudinal direction of the base 4 are placed on the struts 22 of the warp measuring device 20, and the base is measured by a non-contact type distance measuring sensor 21 attached to the upper and lower sides of the warp measuring device 20. The warpage of the upper and lower surfaces of 4 is measured.

  In the present embodiment, three distance measuring sensors 21 are arranged on the upper and lower surfaces of the center portion and both end portions of the base 4 respectively. Unevenness can be measured.

  If it does so, as shown in FIG. 18, the protrusion amount D of the center part of the base 4 with respect to the both ends of the base 4 can be calculated | required. And as shown in FIG. 19, the plate-shaped member 26 which made the protrusion amount D plate | board thickness can be selected.

(Attaching the housing to the base)
Thereafter, as shown in FIG. 20, when the base 4 is placed on the flat surface 24 of the surface plate 23 in order to attach the housing 5 to the base 4, a plate-like member 26 is provided between the lower surface of both ends of the base 4 and the flat surface 24. Put.

  Then, as shown in FIG. 21, even if the housing 5 is pressed against the upper surface of the base 4, the base 4 does not warp due to the pressing force of the housing 5 against the base 4. Even after the substrate is bonded and fixed to the base 4, the housing 5 and the lens array 6 do not warp, and the imaging line 9 can be made straight.

  As described above, the present invention can achieve the same effects as those of the first embodiment.

A third embodiment according to the present invention will be described with reference to FIGS.
FIG. 23 is a schematic view (front view) showing the measurement state of the warp of the base, FIGS. 24 and 25 are front views showing the assembled state of the LED print head, FIG. 26 is a front view of the LED print head, and FIG. 28 is a front view of the plate-like member, FIGS. 29 and 30 are front views showing the assembled state of the LED print head, and FIG. 31 is a front view of the LED print head.

The deflection amount of the LED print head, base, etc. is about several tens of μm. However, in order to make the explanation easier to understand, in FIG. 23 to FIG. Yes.
Further, only differences from the first embodiment will be described, and the same parts as those of the first embodiment will be denoted by the same reference numerals and description thereof will be omitted.

  The main difference between the third embodiment and the first embodiment is that the center of the upper surface of the base is warped so as to be a convex portion, and the flatness of the lower surface of the base is high.

(Conventional problem)
As shown in FIG. 24, when the central portion of the upper surface of the base 4 is a convex portion (both ends of the upper surface of the base 4 are concave portions), there is no gap between the lower surface of the base 4 and the flat surface 24. Can be placed on a flat surface 24 formed on the upper surface of the surface plate 23.

  For this reason, when the housing 5 to which the lens array 6 is attached is pressed against the upper surface of the base 4, as shown in FIG. 25, the substantially central portion of the housing 5 opens outward, and the substantially central portion of the housing 5 is crushed. It becomes a state. When the pressure applied to the base 4 of the housing 5 is continued until the adhesive applied to the boundary portion between the housing 5 and the base 4 is solidified, when the pressure is released, as shown in FIG. The problem of turning.

Therefore, when the housing 5 is attached to the base 4, it is necessary to take means for solving the above problems.
(Measurement of warpage)
First, as shown in FIG. 23, both ends in the longitudinal direction of the base 4 are placed on the struts 22 of the warp measuring device 20, and the bases are measured by the non-contact type distance measuring sensors 21 attached to the upper and lower sides of the warp measuring device 20, respectively. The warpage of the upper and lower surfaces of 4 is measured.

  In the present embodiment, three distance measuring sensors 21 are arranged on the upper and lower surfaces of the center portion and both end portions of the base 4 respectively. Unevenness can be measured.

  Then, as shown in FIG. 27, the protrusion amount E of the central portion of the upper surface of the base 4 with respect to both end portions of the base 4 can be obtained. Then, as shown in FIG. 28, a plate-like member 27 having a thickness obtained by dividing the protruding amount E by 2 is selected.

(Attaching the housing to the base)
Thereafter, as shown in FIG. 29, when the base 4 is placed on the flat surface 24 of the surface plate 23 in order to attach the housing 5 to the base 4, a plate-like member 27 is provided between the lower surface of the both ends of the base 4 and the flat surface 24. Put.

  Then, as shown in FIG. 30, when the housing 5 is pressed against the upper surface of the base 4, the lower surface of the base 4 is warped downward by the same amount as the plate thickness E / 2, and the central portion of the lower surface of the base 4 is brought into the plane 24. Contact. For this reason, after the housing 5 and the base 4 are attached using an adhesive, when the LED print head 1 is removed from the surface plate and the chuck 19, the base 4 returns to the original state as shown in FIG. Although the top surfaces of the array 6 and the base 4 are warped, the imaging line 9 can be straight.

  As described above, according to the present invention, it is possible to reduce the cost of the base 4 by reducing the height of the base 4 in the vertical direction, that is, the thickness of the base 4. As a result, the cost of the LED print head 1 can be reduced. be able to. And the problem of the curvature which generate | occur | produces by making the thickness of the base 4 thin can be solved, and the linearity of the imaging line which each light emission point forms through a lens array can be made highly accurate.

A fourth embodiment according to the present invention will be described with reference to FIGS.
FIG. 32 is a schematic diagram for explaining the measurement of warpage of the base, FIGS. 33 and 34 are front views showing the assembled state of the LED print head, FIG. 35 is a front view of the LED print head, and FIG. 36 is a front view of the base. FIG. 37 is a front view of the plate-like member, FIGS. 38 and 39 are front views showing the assembled state of the LED print head, and FIG. 40 is a front view of the LED print head.

The deflection amount of the LED print head, base, etc. is about several tens of μm. However, in order to make the explanation easy to understand, in FIG. 32 to FIG. 40, the LED print head, base, etc. are greatly bent and illustrated. Yes.
Further, only differences from the first embodiment will be described, and the same parts as those of the first embodiment will be denoted by the same reference numerals and description thereof will be omitted.

  The main difference of the fourth embodiment from the first embodiment is that both ends of the upper surface of the base are warped so as to be convex, and the flatness of the lower surface of the base is high.

(Conventional problem)
As shown in FIG. 33, when both end portions of the upper surface of the base 4 are convex portions (the central portion of the upper surface of the base 4 is a concave portion), there is no gap between the lower surface of the base 4 and the flat surface 24. Can be placed on a flat surface 24 formed on the upper surface of the surface plate 23.

  For this reason, when the housing 5 to which the lens array 6 is attached is pressed against the upper surface of the base 4, a gap is generated between the central portion of the lower surface of the housing 5 and the central portion of the upper surface of the base 4 as shown in FIG. 34. . Then, when the pressing of the housing 5 to the base 4 is continued until the adhesive (not shown) for fixing the housing 5 to the base 4 is solidified, when the pressing is released, as shown in FIG. The problem arises that the image line 9 is bent.

Therefore, when the housing 5 is attached to the base 4, it is necessary to take means for solving the above problems.
(Measurement of warpage)
First, as shown in FIG. 32, both ends in the longitudinal direction of the base 4 are placed on the support column 22 of the warp measuring device 20, and the non-contact type distance measuring sensors 21 respectively attached to the upper and lower sides of the warp measuring device 20 are used as the base. The warpage of the upper and lower surfaces of 4 is measured.

  In the present embodiment, three distance measuring sensors 21 are arranged on the upper and lower surfaces of the center portion and both end portions of the base 4 respectively. Unevenness can be measured.

  Then, as shown in FIG. 36, the protrusion amounts F and G of both end portions of the upper surface of the base 4 with respect to the center portion of the upper surface of the base 4 can be obtained. Then, as shown in FIG. 37, a plate-like member 28 having a thickness (F + G) / 4 obtained by dividing the average value of the protrusion amounts F and G by 2 is selected.

(Attaching the housing to the base)
Thereafter, as shown in FIG. 38, when the base 4 is placed on the flat surface 24 of the surface plate 23 in order to attach the housing 5 to the base 4, the plate-like member 28 is interposed between the lower surface of the central portion of the base 4 and the flat surface 24. Put.

  Then, as shown in FIG. 39, when the housing 5 is pressed against the upper surface of the base 4, both ends of the lower surface of the base 4 are warped downward by the same amount as the plate thickness (F + G) / 4, and both ends of the lower surface of the base 4 are The part contacts the flat surface 24. For this reason, after the housing 5 and the base 4 are attached using an adhesive, when the LED print head 1 is removed from the surface plate and the chuck 19, the base 4 returns to the original state as shown in FIG. Although the top surfaces of the array 6 and the base 4 are warped, the imaging line 9 can be straight.

  As described above, according to the present invention, it is possible to reduce the cost of the base 4 by reducing the height of the base 4 in the vertical direction, that is, the thickness of the base 4. As a result, the cost of the LED print head 1 can be reduced. be able to. And the problem of the curvature which generate | occur | produces by making the thickness of the base 4 thin can be solved, and the linearity of the imaging line which each light emission point forms through a lens array can be made highly accurate.

A fifth embodiment according to the present invention will be described below.
Only differences from the third embodiment and the fourth embodiment will be described, and the same parts as those of the third and fourth embodiments will be denoted by the same reference numerals and the description thereof will be omitted.

  The main difference between Example 3 and Example 4 in Example 5 is that the warpage of the upper surface of the base 4 is grasped on the upper surface of the LED array of the LED substrate fixed to the upper surface of the base.

  That is, in FIG. 23 or FIG. 32, the positions of the non-contact type sensors 21 at both ends are shifted slightly inward to a position where the upper surface of the LED array can be measured, and the distance to the upper surface of the LED array is measured with this sensor. The amount of unevenness on the upper surface of the LED array at the center and both ends of the LED is measured.

  Thus, by grasping the warpage of the upper surface of the base 4 on the upper surface of the LED array, the plate thickness of the plate-like member can be set with higher accuracy than in the third and fourth embodiments. Furthermore, it can be straightened with high accuracy.

  The above-described embodiments have been illustrated for the purpose of explanation, and the present invention is not limited thereto. Those skilled in the art will recognize from the claims, the detailed description of the invention, and the drawings. Modifications and additions can be made without departing from the technical idea of the present invention.

  For example, in the above-described embodiment, the number of sensors is three in the upper and lower directions. However, the number of sensors is not limited to this.

  In the above-described embodiment, the housing 5 and the base 4 are fixed using an adhesive. However, the housing 5 and the base 4 may be fixed with screws.

  The present invention is applied to a method of manufacturing an LED print head used in a copying machine, a printer, or the like.

Plan view of LED print head (Example 1) Front view of LED print head (Example 1) Enlarged view of the side of the LED print head (Example 1) Schematic diagram for explaining an imaging point (focal position) (Example 1) Schematic diagram for explaining measurement of warpage of base (Example 1) Front view showing an assembled state of an LED print head (Example 1) Front view showing an assembled state of an LED print head (Example 1) Front view of LED print head (Example 1) Front view of base (Example 1) Front view of plate member (Example 1) Front view showing an assembled state of an LED print head (Example 1) Front view showing an assembled state of an LED print head (Example 1) Front view of LED print head (Example 1) Schematic diagram for explaining measurement of warpage of base (Example 2) Front view showing an assembled state of an LED print head (Example 2) Front view showing an assembled state of an LED print head (Example 2) Front view of LED print head (Example 2) Front view of base (Example 2) Front view of plate member (Example 2) Front view showing an assembled state of the LED print head (Example 3) Front view showing an assembled state of the LED print head (Example 3) Front view of LED print head (Example 3) Schematic diagram for explaining measurement of warpage of base (Example 3) Front view showing an assembled state of the LED print head (Example 3) Front view showing an assembled state of the LED print head (Example 3) Front view of LED print head (Example 3) Front view of base (Example 3) Front view of plate-like member (Example 3) Front view showing an assembled state of the LED print head (Example 3) Front view showing an assembled state of the LED print head (Example 3) Front view of LED print head (Example 3) Schematic diagram for explaining measurement of warpage of base (Example 4) Front view showing state of assembly of LED print head (Example 4) Front view showing state of assembly of LED print head (Example 4) Front view of LED print head (Example 4) Front view of base (Example 4) Front view of plate member (Example 4) Front view showing state of assembly of LED print head (Example 4) Front view showing state of assembly of LED print head (Example 4) Front view of LED print head (Example 4)

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 LED print head 2 LED array 3 LED board 4 Base 5 Housing 9 Imaging line 22 Column 24 Plane 25 Plate member 26 Plate member 27 Plate member 28 Plate member

Claims (5)

In a method of manufacturing an LED print head, a housing in which a lens array is fixed is fixed to a base on which an LED substrate having a plurality of LED arrays is fixed on an upper surface so that the lens array faces the LED substrate.
By measuring the warpage in the longitudinal direction on the lower surface of the base at at least three points including both ends and the center of the base, the amount of protrusion of the center with respect to the ends, or each of the ends with respect to the center The amount of protrusion of
When the base is placed on a flat surface in order to fix the housing to the base,
When the both end portions protrude from the center portion, a plate-like member having the same thickness as the protrusion amount of the both end portions with respect to the center portion is placed on the center portion of the lower surface of the base. ,
When the central portion protrudes from the both end portions, after placing plate-like members having the same thickness as the protruding amount of the central portion with respect to the both end portions at the both end portions of the lower surface of the base,
A method of manufacturing an LED print head, wherein the housing is fixed to the upper surface of the base while being pressed. In a method of manufacturing an LED print head, a housing in which a lens array is fixed is fixed to a base on which an LED substrate having a plurality of LED arrays is fixed on an upper surface so that the lens array faces the LED substrate.
By measuring warpage in the longitudinal direction on the upper surface of the base at at least three points including both ends and the center of the base, the amount of protrusion of the center with respect to the ends, or each of the ends with respect to the center The amount of protrusion of
When the base is placed on a flat surface in order to fix the housing to the base,
When the both end portions protrude from the central portion, a plate-like member having a thickness that is half the average value of the protrusion amount of the both end portions with respect to the central portion is placed on the central portion on the lower surface of the base. rear,
When the central portion protrudes from the both end portions, after placing plate-like members having a thickness half of the protruding amount of the central portion relative to the both end portions at the both end portions of the lower surface of the base,
A method of manufacturing an LED print head, wherein the housing is fixed while being pressed against an upper surface of the base with a pressing force by which the base is bent. In a method of manufacturing an LED print head, a housing in which a lens array is fixed is fixed to a base on which an LED substrate having a plurality of LED arrays is fixed on an upper surface so that the lens array faces the LED substrate.
By measuring the warpage in the longitudinal direction on the upper surface of the base at at least three points including the upper surface of the LED array at both ends of the LED substrate and the upper surface of the LED array at the center, the central portion with respect to the both ends. The amount of protrusion of each, or the amount of protrusion of each of the both ends relative to the central portion,
When the base is placed on a flat surface in order to fix the housing to the base,
When the upper surface of the LED array at both ends protrudes from the upper surface of the LED array at the center, the amount of protrusion of the upper surface of the LED array at the both ends with respect to the upper surface of the LED array at the center After placing a plate-like member having a thickness half of the average value in the central portion of the lower surface of the base,
When the upper surface of the LED array at the center portion protrudes from the upper surface of the LED array at the both end portions, the protrusion amount of the upper surface of the LED array at the center portion with respect to the upper surface of the LED array at the both end portions After placing a half-thick plate-like member on both ends of the lower surface of the base,
A method of manufacturing an LED print head, wherein the housing is fixed while being pressed against an upper surface of the base with a pressing force by which the base is bent.   Furthermore, the manufacturing method of the LED print head as described in any one of Claims 1-3 which attaches the positioning pin for positioning the said LED print head with respect to an image forming apparatus to the said both ends of the said base.   5. The method of manufacturing an LED print head according to claim 1, wherein the base is supported in the vicinity of the both ends of the base when measuring the warpage in the longitudinal direction on the lower surface or the upper surface of the base.