JP2004148630A - Method for correcting optical print head, optical print head, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate unevenness of pitch in a conventional optical print head by arranging on a line identical to the optical axis of a light emitting array chip. <P>SOLUTION: Quantity of light is corrected by performing following steps (1)-(4) sequentially. (1) Focus is adjusted using a light detecting means at least at two points in the longitudinal direction of a light emitting array emitting light and a rod lens array and both arrays are arranged in parallel along the longitudinal direction. (2) The rod lens array is secured to a means which can adjust that position. (3) Optical characteristics are detected for the vicinity of one end of the rod lens array and adjusted finely by the position adjusting means. (4) Optical characteristics are detected for the vicinity of the other end of the rod lens array and adjusted finely by the position adjusting means. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method of correcting an optical print head used as an exposure unit of an image forming apparatus such as an electrophotographic printer, a facsimile, a copying machine, and the like, and further relates to an optical print head and an image forming apparatus using the correction method of the present invention. It concerns the device.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an optical print head has been used as an exposure unit of an electrophotographic printer, a facsimile, a copying machine, or the like.
[0003]
In such a conventional optical print head, a plurality of light emitting element array chips in which a large number of light emitting elements are linearly arranged are arranged in a line on the upper surface of a circuit board, and a rod lens is provided on these light emitting element array chips. A structure in which a rod lens array such as an array is provided, and the light-emitting elements of the light-emitting element array chip selectively and individually emit light based on external gradation image data, and the light thus emitted is emitted. By irradiating and forming an image on the photoconductor via the rod lens array and forming a predetermined latent image on the photoconductor, the device functions as an exposure unit.
[0004]
Then, the latent image formed on the photoreceptor becomes a toner image through a predetermined developing process, and a predetermined image is recorded on the recording paper by transferring and fixing the toner image on the recording paper.
[0005]
However, according to the above-described conventional optical print head, the light-emitting element array chip is manufactured by a conventionally well-known semiconductor manufacturing technique, and the light-emitting elements of the light-emitting element array chip obtained thereby have uniform light emission characteristics. I didn't. Therefore, even if the same amount of electric power is applied to all the light emitting elements, the light emission amount differs for each light emitting element, and the light spot on the photoreceptor varies, causing the image to be uneven, and the gradation is accurately adjusted. There was a problem that it could not be expressed.
[0006]
In order to solve this problem, light amount correction data corresponding to the light emission characteristics is created so that the amount of light emitted from each light emitting element to the photoconductor is constant, and the driving time of the light emitting element is determined based on the light amount correction data. There has been proposed a technique of adjusting the light emission amount by adjusting (see Patent Document 1).
[0007]
However, the correction method for making the light amount constant cannot suppress the variation in the shape of the light spot formed on the photoconductor caused by the variation in the rod lens array or the light emitting element, and thereby suppresses the unevenness of the print. I couldn't do that.
[0008]
On the other hand, there has been proposed a technique for suppressing variations in print density by using an LED head whose light amount is corrected so that the width and area of a light spot at a predetermined threshold become uniform (Patent Documents 2 and 3). reference).
[0009]
However, it has been found that even with such a technique, it is very difficult to always keep the characteristics of the light spot constant under the conditions actually used.
[0010]
That is, since the amount of supplied power is generally controlled by 4 bits, the controllable amount is limited by the resolution, and when there is a limit, and when the range to be controlled is large, the variation after control becomes large and unevenness occurs. Was causing it to happen.
[0011]
As a technique for reducing such a control amount, instead of keeping the control value constant, a technique of controlling so as to be within a certain distribution to make unevenness less noticeable, a moving average of a correction target value, and the like. There is also proposed a technique of setting the level of variation that cannot be recognized by human vision by using the technique described in Japanese Patent Application Laid-Open Nos. H11-163191, H11-327, and H11-293655.
[0012]
Further, as a technique related to the present invention, there is a technique of uniformly controlling the beam spot width and the dot area on the photosensitive member using the sensitivity of the photosensitive member as a threshold (see Patent Documents 7 and 8).
[0013]
[Patent Document 1]
JP-A-2-62257
[Patent Document 2]
JP-A-8-142406
[Patent Document 3]
JP-A-11-227254
[Patent Document 4]
JP-A-10-181031
[Patent Document 5]
JP 2001-322310 A
[Patent Document 6]
JP-A-2002-127492
[Patent Document 7]
JP-A-4-305667
[Patent Document 8]
JP-A-2002-67372
[0014]
[Problems to be solved by the invention]
As described above, according to the related art, the light amount of the light emitting element and the shape (area, diameter, etc.) of the beam are controlled to values and ranges set in advance. The only correction is to keep the output of the optical print head constant.
[0015]
Therefore, the process of forming a latent image on a photoconductor in order to convert the output of an optical print head into an actual print has been little studied, and in the related art, if the sensitivity of the photoconductor changes, Accordingly, the reference value for control has changed, and accordingly, it has been necessary to determine the value again by performing printing again.
[0016]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for correcting an optical print head with improved convenience for various image carriers such as a photoconductor.
[0017]
It is another object of the present invention to provide an optical print head and an image forming apparatus which achieve uniform light irradiation from a light emitting element array using the correction method of the present invention.
[0018]
[Means for Solving the Problems]
The method for correcting an optical print head according to the present invention includes the steps of: a light emitting element array including a plurality of light emitting elements arranged; and an image carrier for emitting light from the light emitting element array to form an image on the image carrier. The optical system includes a rod lens array and a housing having a frame for holding the rod lens array. The optical position correction is performed through each of the steps (4) to (4).
[0019]
(1) At least two longitudinal positions of both the light emitting element array and the rod lens array that emit light from the respective light emitting elements are adjusted using a light detecting means so that the two light emitting elements are parallel to each other along the longitudinal direction.
[0020]
(2) The rod lens array whose position has been adjusted in the previous step is fixed to a position adjusting means capable of adjusting this position.
[0021]
(3) Optical characteristics are detected near one end of the rod lens array using the light detecting means, and the position is adjusted so that the optical axes of both the light emitting element array and the rod lens array are aligned based on the optical characteristics. Make fine adjustments by adjusting means.
[0022]
(4) Using the light detecting means, optical characteristics are detected in the vicinity of the other end of the rod lens array, and the position is adjusted so that the optical axes of both the light emitting element array and the rod lens array are aligned based on the optical characteristics. Make fine adjustments by adjusting means.
[0023]
According to another method of correcting an optical print head of the present invention, the rod lens array and the frame may be interposed between the steps (3) and (4) or after the steps (3) and (4). The optical position is corrected through a step of inserting an adhesive into the gap to fix the two together.
[0024]
According to still another method of correcting an optical print head of the present invention, after the step (4), the optical position is corrected through the following step (5).
[0025]
(5) Optical characteristics of a portion between one end and the other end of the rod lens array are detected using the light detecting means, and the light of both the light emitting element array and the rod lens array is detected based on the optical characteristics. Fine adjustment is made by the position adjusting means in order to align the axes.
[0026]
Further, the method of correcting an optical print head according to the present invention may be arranged such that a rod lens is used in the course of each of the steps (3), (4) and (5) or after the steps (3), (4) and (5). The optical position is corrected through a step of inserting an adhesive into a gap between the array and the frame to fix the two together.
[0027]
The optical print head of the present invention is characterized by having passed through the optical print head correcting method of the present invention.
[0028]
An image forming apparatus according to the present invention includes the optical print head according to the present invention and the image carrier.
[0029]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is an exploded perspective view showing a main part of an optical print head L according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the optical print head L. FIG. 3 is a front view showing a schematic configuration of a main part of an image forming apparatus on which the optical print head L is mounted. According to this apparatus, the optical print head L and the image carrier And a photosensitive member (photosensitive drum) P. FIG. 4 is a circuit diagram of a driver IC 4 for applying a voltage to the light emitting element array.
[0030]
First, the function of the optical print head L will be described with reference to FIGS. 1, 3, and 4.
According to the optical print head L, a plurality of light emitting element array chips 2 and driver ICs 4 are mounted on the upper surface of the circuit board 1 and the rods forming the imaging optical system are formed on the light emitting surfaces of the light emitting element array chips 2. The lens array 5 is arranged.
[0031]
The circuit board 1 is formed by attaching a large number of circuit wirings in a predetermined pattern on an upper surface of a rectangular base made of an electrically insulating material such as a glass cloth base epoxy resin, glass, or ceramic. The light emitting element array chip 2 and the driver IC 4 are supported.
[0032]
When the circuit board 1 is made of, for example, a glass cloth epoxy resin base material, a glass cloth base material formed by using a glass thread is impregnated with a liquid epoxy resin and cured, and then cut into a rectangular shape to obtain an outer shape. After processing, a copper foil or the like is stuck on the upper surface, and this is etched into a predetermined shape to pattern circuit wiring.
[0033]
The plurality of light emitting element array chips 2 mounted on the circuit board 1 are arranged in a line along the longitudinal direction of the circuit board 1, and have a density of, for example, 600 dpi (dot per inch) on each upper surface. And a plurality of connection pads electrically connected to the light-emitting element 3. Each of these connection pads is connected to a circuit wiring on the circuit board 1 via a bonding wire. Is electrically connected to the
[0034]
The light-emitting element 3 is made of, for example, a GaAlAs-based or GaAsP-based light-emitting element, and is formed by pn-junction of a p-type semiconductor and an n-type semiconductor. The light-emitting element 3 is externally connected to the light-emitting element 3 via circuit wiring and connection pads. When power is applied, electrons are injected into the p-type semiconductor and holes are injected into the n-type semiconductor, and these carriers recombine near the pn junction. By converting the light into light, the light emitting element 3 emits light at a predetermined luminance.
[0035]
A predetermined energy is externally applied to the light emitting element 3 based on the image data, and the light emitting element emits light for a predetermined time corresponding to the image data.
[0036]
On the other hand, as shown in FIG. 4, a driver IC 4 mounted on the circuit board 1 includes a gradation control unit 4A for controlling a gradation level of light of the light emitting element 3 based on external image data, and a light amount correction unit. It is configured to include a light amount correction unit 4B for adjusting the light emission amount of the light emitting element 3 based on the data, and a large number of constant current power supply groups R provided in one-to-one correspondence with the light emitting element 3.
[0037]
The gradation control unit 4A supplies a shift register for serially transferring gradation image data from the outside, a latch for temporarily storing these image data, and a strobe signal in the latch while the strobe signal is supplied. A conduction time of a current supplied from the constant current power supply group R to the light emitting element 3 based on the gradation image data in the latch, which is constituted by a gate circuit or the like that issues a predetermined output to the constant current power supply group R based on the image data , The gradation of light emitted from the light emitting element 3 is controlled.
[0038]
The light amount correction unit 4B includes a shift register for serially transferring the calculated light amount correction data and a latch for temporarily storing the light amount correction data, and the light amount correction stored in the latch. The light emission amount of the light emitting element 3 is adjusted by switching the current value of the current supplied from the constant current power supply group to the light emitting element 3 based on the data.
[0039]
The constant current power supply group R includes a plurality of constant current power supplies, and one or more of these constant current power supplies are selected based on the light quantity correction data stored in the latch of the light quantity correction unit 4B. As a result, the current value is switched.
[0040]
The driver IC 4 having such a circuit configuration is electrically connected to the corresponding circuit wiring on the circuit board 1 via bonding wires, similarly to the light emitting element array chip 2 described above.
[0041]
Further, the rod lens array 5 arranged on the light emitting element array chip 2 is for irradiating the light emitted from the light emitting element 3 onto the external photosensitive drum P and forming an image. A rod lens array or the like formed by arranging a large number of rod-shaped lenses in a linear or staggered manner is used, and is fixed at a predetermined position by a lens holder or the like (not shown) with an adhesive.
[0042]
The rod lens array 5 is an erecting equal-magnification optical system in which rod-shaped lenses made of a transparent material such as acrylic resin or glass are linearly or staggered in the main scanning direction. Arranged on the light emitting surface of the array chip 2 substantially in parallel with the arrangement of the chips 2, the light emitted from the light emitting diode elements 2 is irradiated and imaged on the photosensitive drum (photosensitive body) P at the same magnification.
[0043]
The photoconductor drum (photoconductor) P is disposed on the light emitting element array chip 2 of the optical print head L so as to be separated from the optical print head L by a predetermined distance and substantially parallel to the optical print head L. .
[0044]
The photoconductor drum P has a structure in which a photoconductive layer made of an inorganic semiconductor such as selenium or amorphous silicon or an organic semiconductor is adhered to an outer surface of a cylindrical base made of aluminum or the like. When the photoconductive layer is irradiated with light from the optical print head L by being rotated around the axis by, for example, the photoconductive layer, the specific resistance of the photoconductive layer is rapidly reduced, and a predetermined latent image is formed on the photoconductive layer. The latent image formed on the photosensitive drum P becomes a toner image through a developing process, and a predetermined image is recorded by transferring and fixing the toner image on recording paper.
[0045]
The optical print head L for recording an image as described in detail above. The configuration of the imaging optical system will be further described with reference to FIG.
[0046]
As shown in the figure, the imaging optical system includes a rod lens array 5 and a housing H having a frame P that sandwiches the rod lens array 5. Then, on the circuit board 1, a housing 4 having a rod lens array 5 mounted thereon is placed.
[0047]
B is a base plate as a head base material for holding the circuit board 1, S is an adhesive for fixing the rod lens array 5 to the frame P, and K is a holder for integrally holding the housing H with the base plate B. It is.
[0048]
The housing H has a frame P at a lower portion thereof, a reference surface abutting on the upper surface of the circuit board 1, an upper portion into which the rod lens array 5 is inserted, and the rod lens array 5 sandwiched therebetween. Further, the housing H and the circuit board 1 form a closed space for accommodating the light emitting element array chip 2.
[0049]
The housing H is formed of, for example, a plastic material such as a liquid crystal polymer and a metal material such as stainless steel and aluminum. When it is made of a plastic material, it is manufactured by molding a plastic material into a predetermined shape, for example, by adopting a conventionally known injection molding method.
[0050]
In the above-described embodiment, a base plate B made of SUS or the like may be disposed below the circuit board 1, and the circuit board 1 may be sandwiched between the base plate B and the lens holder H. In this case, it is preferable to use a leaf spring-shaped holder K to hold the three members of the base plate B, the circuit board 1 and the lens holder H. With such a clip, the base plate B, the circuit board 1 and the lens holder H are held together. The optical printer head can be held integrally, so that the structure of the optical printer head and the assembling operation can be simplified.
[0051]
According to the optical print head L of the present invention, the rod lens array 5 and the head L are added to the above-described configuration according to the correction method of the present invention described later, that is, in order to manufacture the optical print head L. By rotating or moving three-dimensionally in each of the X, Y, and Z directions, adjustment is performed with high accuracy, so that the center axis of the rod lens array 5 and the center of the light emitting element array chip 2 match. And mounted on the same straight line as the optical axis of the light emitting element array chip 2.
[0052]
Thus, the light-emitting element forming the light-emitting element of the light-emitting element array chip 2 and the central axis and the imaging position of the rod lens array 5 are on a straight line, and the optical axis is connected to a straight line. Pitch unevenness existing in the head does not occur.
[0053]
According to the optical print head L, when the light emitting element array chip 2 and the rod lens array 5 are fixed according to the optical print head L, the positional relationship between the light emitting element array chip 2 and the focal length of the light emitting element array chip 2 is (focal length−100 μm). ) To (focal length + 100 μm), it was confirmed by repeated experiments that an optimum printing state was obtained.
[0054]
Next, a method of correcting the optical print head L having the above configuration will be further described with reference to FIGS.
[0055]
FIG. 5 is a schematic view of a measuring device for light quantity correction. 6 and 7 show a conventional correction method which does not employ the correction method of the present invention. FIG. 6 is a cross-sectional view and FIG. 7 is a front view. 8 and 9 show the correction method of the present invention. FIG. 8 is a cross-sectional view and FIG. 9 is a front view. FIG. 10 is a top view of the rod lens array 5.
The steps (1) to (4) are sequentially performed.
[0056]
Step (1):
Each light emitting element array chip 2 is caused to emit light, and the light emitting element array chip 2 and the rod lens array 5 are both focused in at least two positions in the longitudinal direction using a light detecting means, so that the two light emitting element array chips 2 are moved in the longitudinal direction. And then make it parallel.
[0057]
This step will be described with reference to FIG. FIG. 3 is a schematic diagram of a measuring device for correcting the amount of light used to make the light source parallel as described above.
[0058]
For the measurement of the light emission output, the rod lens array 5 is inserted into the housing H, and the rod lens array 5 is held by the frame P. Thereafter, the light emitted from the light emitting element 3 of the light emitting element array chip 2 is directly observed by the CCD camera 6. For example, the center of the light emitting element of the light emitting element 3 located at the left end when viewed from the front in FIG. Detection is performed by the CCD camera 6, and the focus is adjusted by moving the CCD camera 6.
[0059]
Next, by focusing at the left end, the head body is moved or the CCD camera 6 is moved while keeping the focus position unchanged, so that the light emitting element 3 of the light emitting element 3 located at the right end is moved. The CCD camera 6 is opposed, and the center of the luminous body is detected by the CCD camera 6. Further, the center of the luminous body located at the right end is detected as it is, and the left end luminous body is kept so that the focus position at the left end does not change. The focus is adjusted by moving the head around the center of rotation.
The Z direction is adjusted by the above steps.
[0060]
Step (2):
The rod lens array 5 whose position has been adjusted in the previous step is fixed to a position adjusting means capable of adjusting this position.
[0061]
That is, the rod lens array 5 is generally fixed to the housing H of the head main body in the frame P above the head H by vacuum suction or a clamp.
[0062]
The position adjusting means is a mechanism including a vacuum suction or a clamp for fixing the rod lens array 5 sandwiched between the frame P of the housing H and the rod lens array 5. The position of the rod lens array 5 can be adjusted by a mechanism.
[0063]
Step (3):
Next, an optical characteristic is detected near one end of the rod lens array 5 using a CCD camera 6 as light detecting means, and the light of both the light emitting element array chip 2 and the rod lens array 5 is detected based on the optical characteristic. Fine adjustment is made by the position adjusting means in order to align the axes. In this step, the Y direction is adjusted.
[0064]
Specifically, for example, the upper left end of the rod lens array 5 is recognized using the CCD camera 6, and the center of the rod lens array 5 is moved by moving the rod lens array 5 to focus. For reference, as shown in FIG. 6, the center of the rod lens array refers to the center in the Y direction of a plurality of arranged rod lens arrays indicated by a chain line a.
[0065]
Step (4):
In this step, an optical characteristic is detected near the other end of the rod lens array 5 using a CCD camera 6 as a light detecting means, and the light emitting element array chip 2 and the rod lens array 5 are further detected based on the optical characteristic. Fine adjustment is made by the position adjusting means in order to align both optical axes. In this step, adjustment is performed with higher accuracy in the Y direction.
[0066]
That is, using the CCD camera 6, for example, the right end upper surface of the rod lens array 5 is recognized, and the center of the rod lens array 5 is moved by moving the rod lens array 5 to focus.
[0067]
Thus, according to the method of correcting the optical print head L of the present invention, the steps (1) to (4) can be performed with high accuracy in the Z direction and the Y direction. And the central axis and the image forming position of the rod lens array 5 can be present on a substantially straight line, and the optical axis is connected to a straight line. .
[0068]
According to the present invention, the pitch unevenness can be prevented from occurring by performing the above-described steps (1) to (4). However, it is preferable that the pitch unevenness be generated with higher accuracy. In order to eliminate this, it is preferable to go through step (5) following step (4).
[0069]
Step (5):
Optical characteristics are detected for a portion between one end and the other end of the rod lens array 5 using a CCD camera 6 as light detecting means, and the light emitting element array chip 2 and the rod lens array are detected based on the optical characteristics. Fine adjustment is made by the position adjusting means in order to align both optical axes of No. 5.
[0070]
For example, the right end of the rod lens array 5 is detected by using the CCD camera 6, and the left end of the rod lens array 5 is focused by moving the rod lens array 5 with its axis as a rotation axis.
[0071]
By the fine adjustment operation in the step (5), the rod lens array 5 and the head main body are parallel to the CCD camera 6, and the center of the rod lens array 5 and the center of the light emitter are arranged on the same straight line. Was done.
[0072]
More specifically, the CCD camera 6 is moved from the light-emitting body to a virtual imaging position, the rod lens array 5 is moved so as to be parallel between the CCD of the CCD camera 6 and the head body, and the focus is adjusted to the CCD. In this case, the light-emitting body, the rod lens array 5, and the rod lens array 5 have the same image forming position, and the positioning has been performed.
[0073]
If there is a deviation from the position where the luminous body was recognized first, the rod lens array 5 is rotated in the θ direction, so that the rod lens array 5 is rotated in the θ direction and adjusted to the luminous body position. As a result, the optical axis also coincides on a straight line.
[0074]
Thus, according to the method of correcting the optical print head L of the present invention, the optical position is corrected through the step (5) after the step (4), that is, in the θ direction also in the X direction. Rotation can be adjusted with high precision, so that the light-emitting element forming the light-emitting element of the light-emitting element array chip 2 and the central axis and the image forming position of the rod lens array 5 can be aligned. In addition, the optical axis has a structure in which straight lines are connected with high precision, and pitch unevenness does not occur.
[0075]
According to the present invention, the rod lens array 5 is placed in the housing H of the head main body with high precision through the above-described steps (1) to (4) and further steps (1) to (5). The adhesive S is used for fixing.
[0076]
An air layer 7 (gap) having a thickness of 30 μm to 300 μm is preferably provided between the rod lens array 5 and the frame body P, so that the amount of the adhesive S made of a synthetic resin material can be adjusted with an appropriate amount. Can be filled.
[0077]
That is, after completion of each of the steps (1) to (4) or (1) to (5), the mixture is gradually filled in an appropriate amount and partially fixed, and finally, the step (4) or After the step (5) is completed, the last adhesive S may be filled with an appropriate amount.
[0078]
Alternatively, since the rod lens array 5 is supported by using the position adjusting means, the adhesive S is filled with an appropriate amount after the last step (4) or step (5) is completed, and The rod lens array 5 may be fixed in the housing H of the head body.
[0079]
Note that an air layer 7 (gap) having a thickness of 30 μm to 300 μm is preferably provided between the rod lens array 5 and the frame P, but the side surface of the rod lens array 5 is It may be non-contacting or partially contacting the side surface.
[0080]
As the adhesive S, for example, a moisture-curable instant adhesive may be used. As the instant adhesive, a moisture-curable instant adhesive of a cyanoacrylate resin or the like is suitable.
[0081]
Then, most of the adhesive S is preferably arranged at a corner formed by the upper surface of the frame P and the side surface of the rod lens array 5.
[0082]
The rod lens array 5 is fixed to the frame P by first attaching an accelerator, which is a curing accelerator adjusted to a liquid having a viscosity of about 0.01 Pa · s to 5 Pa · s, to the side surface of the rod lens array 5. Then, the adhesive S applied from the upper end surface to the outer surface of the frame body P with a dispenser, a brush or the like, and adjusted to a liquid having a viscosity of about 0.01 Pa · s to 5 Pa · s is applied to the side surface of the rod lens array 5. The adhesive is applied from the upper end surface to the outer surface of the frame P with a dispenser, a brush, or the like so as to be attached.
[0083]
Thus, by using the above-described method of correcting the optical print head L, according to the optical print head L of the present invention and the image forming apparatus of the present invention obtained as described above, a good printing state was obtained.
[0084]
That is, since the optical characteristics of the rod lens array 5 are well maintained as described above, the surface of the photoreceptor is irradiated with light of almost constant intensity with little variation on the line, A clear image corresponding to the image data was obtained. Then, the latent image formed on the photoreceptor became a toner image through a developing process, and a predetermined image could be recorded on the recording paper by transferring and fixing the toner image on the recording paper.
[0085]
The present invention is not limited to the above-described embodiment, and various changes, improvements, and the like may be made without departing from the spirit of the present invention.
[0086]
For example, in the above-described embodiment, a CCD camera is used to measure the light emission intensity. However, instead of this, another light amount detecting means such as a photodiode or a photomultiplier may be used.
[0087]
In the above-described embodiment, the rod lens array 5 is used as the imaging optical system. Alternatively, a monocular rod lens array in which aspheric lenses are arranged with high accuracy may be used. Note that the monocular rod lens array is equivalent to the rod lens array described in the claims.
[0088]
Further, as the adhesive S, a sealing material made of a silicone resin or the like may be used instead of the moisture-curable instant adhesive of cyanoacrylate resin.
[0089]
【The invention's effect】
As described above, according to the optical print head correction method of the present invention, (1) light detection means is used for at least two positions in the longitudinal direction of both the light emitting element array and the rod lens array that emitted each light emitting element. (2) The rod lens array whose position has been adjusted in the previous step is fixed to a position adjusting means capable of adjusting this position, (3) the light detection Means for detecting the optical characteristics of the vicinity of one end of the rod lens array, and fine-adjusting the position adjusting means to align the optical axes of both the light emitting element array and the rod lens array based on the optical characteristics. (4) Using the light detecting means, optical characteristics are detected near the other end of the rod lens array, and further based on the optical characteristics, the light emitting element array and the rod lens array are detected. Fine adjustment is made by the position adjusting means so as to align both optical axes, and further (5) the light detecting means is used to optically adjust a portion between one end and the other end of the rod lens array. The optical print head is subjected to each step of detecting the characteristics and fine-adjusting with the position adjusting means so as to align the optical axes of both the light emitting element array and the rod lens array with the optical characteristics. In order to manufacture the rod lens array, the rod lens array and the head are rotated or three-dimensionally moved in each of the X, Y, Z, and θ directions to adjust with high accuracy. It is mounted with the center axis of the light emitting element array chip coincident with the center axis of the light emitting element array chip, and is present on the same straight line as the optical axis of the light emitting element array chip. The pitch unevenness no longer occurs.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of an optical print head L of the present invention.
FIG. 2 is a cross-sectional view of the optical print head L of the present invention.
FIG. 3 is a front view showing a schematic configuration of the image forming apparatus of the present invention.
FIG. 4 is a circuit diagram of a driver IC for applying power to a light emitting element array according to the present invention.
FIG. 5 is a schematic diagram of a measuring device for light quantity correction used for creating light quantity correction data.
FIG. 6 is a cross-sectional view of the optical print head L.
FIG. 7 is a front view of the optical print head L.
FIG. 8 is a cross-sectional view of the optical print head L.
FIG. 9 is a front view of the optical print head L.
FIG. 10 is a three-dimensional perspective view showing a light emission intensity distribution of the light emitting element.
[Explanation of symbols]
L: Optical print head
P: photoconductor (photoconductor drum)
1 ... circuit board
2 ... Light-emitting element array chip
3 Light emitting element
4: Driver IC
5 ... Rod lens array

Claims (6)

A light-emitting element array in which a plurality of light-emitting elements are arranged, and an imaging optical system arranged between the light-emitting element array and the image carrier to form an image on the image carrier. The above-mentioned imaging optical system sequentially performs an optical print head having a rod lens array and a housing having a frame for holding the rod lens array through the following steps (1) to (4). An optical printhead correction method for position correction.
(1) At least two longitudinal positions of both the light emitting element array and the rod lens array that emit light from the respective light emitting elements are adjusted using a light detecting means so that the two light emitting elements are parallel to each other along the longitudinal direction.
(2) The rod lens array whose position has been adjusted in the previous step is fixed to a position adjusting means capable of adjusting this position.
(3) Optical characteristics are detected near one end of the rod lens array using the light detecting means, and the position is adjusted so that the optical axes of both the light emitting element array and the rod lens array are aligned based on the optical characteristics. Make fine adjustments by adjusting means.
(4) Using the light detecting means, optical characteristics are detected in the vicinity of the other end of the rod lens array, and the position is adjusted so that the optical axes of both the light emitting element array and the rod lens array are aligned based on the optical characteristics. Make fine adjustments by adjusting means. A step of inserting an adhesive into the gap between the rod lens array and the frame during the steps (3) and (4) or after the steps (3) and (4) to fix the two together. 2. The optical print head correction method according to claim 1, wherein the optical position correction is performed via the following. An optical print head correction method for performing optical position correction through the following step (5) after the step (4) of claim 1.
(5) Optical characteristics of a portion between one end and the other end of the rod lens array are detected using the light detecting means, and the light of both the light emitting element array and the rod lens array is detected based on the optical characteristics. Fine adjustment is made by the position adjusting means in order to align the axes. An adhesive is inserted into the gap between the rod lens array and the frame during the steps (3), (4) and (5) or after the steps (3), (4) and (5). 4. The method for correcting an optical print head according to claim 3, wherein the optical position is corrected through a step of fixing the both. An optical print head having undergone the optical print head correction method according to claim 1. An image forming apparatus comprising the optical print head according to claim 5 and the image carrier.

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