JP4808929B2 - Exposure apparatus manufacturing method and light source adjusted exposure apparatus - Google Patents

Description

The present invention relates to an exposure apparatus manufacturing method for exposing a photosensitive material using an LED as a light source and an adjusted exposure apparatus.

  An LED is used as a light source in an image forming apparatus that forms an image by exposing a photosensitive material. LEDs have the advantages of small size, long life, and low cost. However, the light emitted from the LED has a predetermined spectral characteristic, and the photosensitive material exposed by the LED also has a predetermined spectral sensitivity characteristic. FIG. 15 shows an example 1501 of spectral characteristics of light emitted from the LED for R light, an example 1502 of spectral characteristics of light emitted from the LED for G light, and a spectral characteristic of light emitted from the LED for B light. An example 1503 is shown. Further, FIG. 15 shows an example 1511 of an R color spectral sensitivity characteristic, an example 1512 of a G color spectral sensitivity characteristic, and an example 1513 of a B color spectral sensitivity characteristic of the photosensitive material. In FIG. 15, the horizontal axis indicates the wavelength λ (nm), and the vertical axis indicates the relative light quantity L and the relative sensitivity R.

  In this way, the spectral characteristics of the LEDs of each color and the spectral sensitivity characteristics of the photosensitive material are not equal. Therefore, in order to obtain a constant density image, the spectral characteristics of the light emitted from the LED and the spectral sensitivity of the photosensitive material exposed by the LED. It is necessary to consider the characteristics. In particular, there are individual differences in LEDs, and there may be variations in the wavelength of light emitted from the LEDs. Therefore, in consideration of the wavelength of light emitted from the LED, an attempt is made to correct the current value applied to the LED by correcting the correction coefficient table by the LED correction setting means to obtain an image with a constant density ( For example, see Patent Document 1.)

JP-A-61-58283 (Page 2 and FIG. 7)

  However, in the correction of the current value applied to the conventional LED, specifically, how to detect the spectral characteristic of the light emitted from the LED and how to correct the current value applied to the LED It was not clear.

  In addition, there are individual differences in LEDs, and not only spectral characteristics of light emitted from the LEDs but also variations in the amount of light may occur. Therefore, in order to obtain an image with a constant density, the spectral characteristics and light quantity of light emitted from the LED and the spectral sensitivity characteristics of the photosensitive material are all considered, and the spectral characteristics and light quantity variation of the light emitted from the LED are considered. Must be accurately measured to adjust the exposure apparatus.

  Furthermore, a CCD sensor for detecting the amount of light emitted from the LED also has spectral sensitivity characteristics. FIG. 16 shows an example 1600 of spectral sensitivity characteristics of a CCD sensor for measuring the amount of light emitted from the LED. In FIG. 16, the horizontal axis indicates the wavelength λ (nm) and the vertical axis indicates the relative sensitivity S. As shown in FIG. 16, it is understood that the relative sensitivity S increases as the wavelength λ increases. Therefore, there has been a problem that the amount of light to be measured changes due to variations in the center wavelength of light emitted from the LED, and the exposure apparatus cannot be adjusted appropriately.

Therefore, the present invention provides an exposure apparatus manufacturing method and an adjusted exposure apparatus that can obtain a constant density image regardless of individual differences of LEDs by measuring the spectral characteristics of light emitted from the LEDs. The purpose is to provide.

In addition, the present invention performs adjustment according to the spectral characteristics and light quantity of light emitted from the LED and the spectral sensitivity characteristics of the photosensitive material, and exposure that can obtain an image with a constant density regardless of individual differences of the LEDs. An object of the present invention is to provide an apparatus manufacturing method and an adjusted exposure apparatus.

Furthermore, the present invention provides an exposure apparatus manufacturing method and an adjusted exposure apparatus capable of obtaining a constant density image regardless of the spectral sensitivity characteristics of a sensor for measuring the amount of light emitted from an LED. The purpose is to provide.

In order to achieve the above object, in the method of manufacturing an exposure apparatus according to the present invention, a step of applying a reference current value to an LED to emit light and measuring the spectral characteristic and the amount of light emitted from the LED, and the spectral characteristic And correcting the LED characteristics based on the light quantity based on the wavelength sensitivity characteristics of the photosensitive material, and determining a set current value so that the corrected LED characteristics become the reference characteristics. . Adjustments are made according to the spectral characteristics of the light emitted from the LED, the amount of light emitted from the LED, and the spectral sensitivity characteristics of the photosensitive material, and an image with a constant density can be obtained regardless of individual differences in the LEDs. Adjust the exposure apparatus as follows.

Further, in the exposure apparatus manufacturing method according to the present invention, the correction step includes a step of obtaining a first LED characteristic based on the spectral characteristic and the light amount, and a sensitivity characteristic of a sensor for measuring the light amount of the first LED characteristic. It is preferable to have a step of obtaining the second LED characteristic by correcting based on the above, and a step of correcting the second LED characteristic based on the wavelength sensitivity characteristic of the photosensitive material.

Furthermore, in the exposure apparatus manufacturing method according to the present invention, it is preferable to simultaneously perform the step of obtaining the second LED characteristic and the step of correcting based on the wavelength sensitivity characteristic of the photosensitive material.

Furthermore, the exposure apparatus manufacturing method according to the present invention preferably includes a step of correcting the reference current value so that the light amount becomes the reference light amount.

Furthermore, in the exposure apparatus manufacturing method according to the present invention, the spectral characteristic is preferably the peak wavelength of light emitted from the LED. In addition, the peak wavelength includes the first half-value wavelength on the long wavelength side having a light amount that is 1/2 of the wavelength having the maximum light amount emitted from the LED, and the light amount that is 1/2 of the wavelength having the maximum light amount. It is preferable to use an imaginary peak wavelength obtained by averaging with the second half-value wavelength on the short wavelength side.

Furthermore, in the method for manufacturing an exposure apparatus according to the present invention, the LED is an R light LED, and the wavelength sensitivity characteristic of the photosensitive material is preferably a wavelength sensitivity characteristic on the long wavelength side.

In order to achieve the above object, in the method of manufacturing an exposure apparatus according to the present invention, a step of applying a first current value to the LED to emit light and measuring the spectral characteristics and the amount of light emitted from the LED. Correcting the first current value so that the light amount becomes the reference light amount, determining the second current value, obtaining the first LED characteristic based on the spectral characteristics and the reference light amount, Correcting the LED characteristics based on the sensitivity characteristics of the sensor for measuring the amount of light to obtain the second LED characteristics, and correcting the second LED characteristics based on the wavelength sensitivity characteristics of the photosensitive material, And determining the third current value by correcting the second current value so that the characteristic of the third LED becomes the reference characteristic. Adjustment is made according to the spectral characteristics of the light emitted from the LED, the amount of light emitted from the LED, the spectral sensitivity characteristics of the photosensitive material, and the sensor sensitivity, and an image with a constant density is obtained regardless of the individual differences of the LEDs. Adjust the exposure apparatus so that it can.

Furthermore, in the manufacturing method of the exposure apparatus according to the present invention, it is preferable that the first LED characteristic is obtained by correcting predetermined LED profile data based on the spectral characteristic and the reference light amount.

  In order to achieve the above object, an exposure apparatus according to the present invention includes a step of applying a reference current value to an LED to emit light, measuring a spectral characteristic and a light amount of light emitted from the LED, a spectral characteristic, According to an adjustment method including a step of correcting an LED characteristic based on a light amount based on a wavelength sensitivity characteristic of a photosensitive material and a step of determining a set current value such that the corrected LED characteristic becomes a reference characteristic, It is characterized by being adjusted. The exposure device makes adjustments according to the spectral characteristics of the light emitted from the LEDs, the amount of light emitted from the LEDs, and the spectral sensitivity characteristics of the photosensitive material, and an image with a constant density is obtained regardless of the individual differences of the LEDs. Adjusted so that it can be obtained.

  In order to achieve the above object, an exposure apparatus according to the present invention includes a step of applying a first current value to an LED to emit light, measuring a spectral characteristic and a light amount of light emitted from the LED, and a light amount. Correcting the first current value so that becomes the reference light amount, determining the second current value, obtaining the first LED characteristic based on the spectral characteristics and the reference light amount, and the first LED characteristic Correcting the light quantity based on the sensitivity characteristic of the sensor for measuring the amount of light to obtain the second LED characteristic, and correcting the second LED characteristic based on the wavelength sensitivity characteristic of the photosensitive material to correct the third LED characteristic And adjusting the second current value so that the characteristic of the third LED becomes the reference characteristic, and determining the third current value, thereby adjusting the LED. And The exposure apparatus performs adjustment according to the spectral characteristics of the light emitted from the LED, the amount of light emitted from the LED, the spectral sensitivity characteristics of the photosensitive material, and the sensor sensitivity. It is adjusted so that an image can be obtained.

  ADVANTAGE OF THE INVENTION According to this invention, it became possible to provide the adjustment method of the exposure apparatus and the adjusted exposure apparatus which can obtain the image of fixed density irrespective of the individual difference of LED.

  In addition, according to the present invention, an image having a constant density can be obtained regardless of individual differences of LEDs by performing adjustment according to the spectral characteristics and light amount of light emitted from the LEDs and the spectral sensitivity characteristics of the photosensitive material. It has become possible to provide an adjustment method for an exposure apparatus and an adjusted exposure apparatus.

  Furthermore, according to the present invention, an exposure apparatus adjustment method and adjusted exposure capable of obtaining an image with a constant density irrespective of the spectral sensitivity characteristic of a sensor for measuring the amount of light emitted from an LED. It became possible to provide a device.

  An example of an adjustment system for carrying out the exposure apparatus adjustment method according to the present invention will be described with reference to FIGS.

FIG. 1 shows an outline of the adjustment system. As shown in FIG. 1, the adjustment system includes an exposure apparatus 100 to be measured, an adjustment apparatus 200, and a control personal computer (hereinafter referred to as a PC) 300. The exposure apparatus 100 is attached to the adjustment apparatus 200 by an attachment (not shown), and the signal line 122 is connected to an interface (hereinafter referred to as IF) 240 of the adjustment apparatus 200. Further, the adjustment device 200 and the PC 300 are connected to each other via a bus line 260 so as to be able to transmit data.

As shown in FIG. 1, the adjustment device 200 includes a CPU 210 for overall control, an LED control condition memory 212 for storing the LED control conditions of the exposure apparatus 100, a table driving circuit 214, a spectral sensor 220, and a CCD sensor. 230, an IF 240 for connection with the exposure apparatus 100, and an IF 250 for connection with the PC 300. The adjustment device 200 also includes a sensor control circuit 222 for controlling the spectroscopic sensor 220 and a detection circuit 224 for detecting a peak wavelength or a half-value wavelength based on a signal from the spectroscopic sensor 220. Further, the adjusting device 200 detects a received light amount for detecting a light receiving amount of each of the plurality of light receiving elements of the CCD control circuit 232 and the CCD sensor 230 for controlling a plurality of light receiving elements of the CCD sensor 230 described later. The circuit 234 and the integration circuit 236 for integrating the detection output of the received light amount detection circuit 234 to obtain received light amount data per predetermined time are provided. Further, the adjusting device 200 is an LED lighting control circuit for controlling the light emission intensity of the LEDs (R light LED, G light LED, and B light LED) included in the exposure device 100 by changing the current value. 242, a liquid crystal shutter drive circuit 244 for driving and controlling a plurality of drive pixels of the liquid crystal shutter array 118 included in the exposure apparatus 100. The signal line 122 connects each LED in the exposure apparatus 100 to the LED control circuit 242, and the liquid crystal shutter array 118 and the liquid crystal shutter drive circuit 244 via the IF 240.

  As shown in FIG. 1, the CPU 210 is connected to the PC 300 via the IF 250 and the bus line 260, and receives control data from the PC 300 regarding the measurement start timing and measurement end timing, the driving conditions of the exposure apparatus 100, and the like. The exposure apparatus 100 and the adjustment apparatus 200 are controlled according to the control data, and the light quantity can be measured. The adjustment device 200 includes a ROM for storing a control program for the CPU 210, a RAM for temporarily storing various data, various signal lines and bus lines for transmitting and receiving data between the components. .

  FIG. 2 shows the appearance of the adjustment system shown in FIG. As shown in FIG. 2, the spectroscopic sensor 220 and the CCD sensor 230 are fixed on a table 270 that can move to the left and right in the drawing. The table 270 is configured to be movable by a table driving circuit 214, and thereby configured to switch measurement between the spectroscopic sensor 220 and the CCD sensor 230.

FIG. 3 shows an outline of the CCD sensor 230. The CCD sensor 230 has 2048 vertical light receiving elements 280, and each light receiving element 280 has a length a of 2500 μm, a width c of 20 μm , and a pitch d (25 μm). FIG. 3 shows each drive pixel 420 of the liquid crystal shutter array 118 described later. Each drive pixel 420 has a length b of 150 μm (or 200 μm), a width e of 76 μm, and a pitch f (100 μm). Has been. Accordingly, four light receiving elements 280 are arranged to correspond to one drive pixel 420. In the present embodiment, the liquid crystal shutter array 118 has 480 drive pixels, and each drive pixel 420 is arranged in a straight line as shown in FIG. However, the drive pixels can be arranged in a staggered arrangement according to the wiring layout of the electrodes for driving the drive pixels. The CCD sensor 230 has a spectral sensitivity characteristic 1600 as shown in FIG.

  Next, an example of the exposure apparatus 100 according to the present invention will be described with reference to FIGS.

  4 is an exploded perspective view of the exposure apparatus 100, and FIG. 5 is a cross-sectional view of the exposure apparatus 100. As shown in the figure, the exposure apparatus 100 includes an upper housing 104 and a lower housing 130, and an upper reflector 106, a light guide element 108, a mirror 112, a lower reflector 114, a liquid crystal shutter array 118, and a liquid crystal shutter array 118 are interposed therebetween. LED120 is arrange | positioned. The upper housing 104 and the lower housing 130 are fixed to each other by the clip 140 so as not to be separated vertically.

  A light shielding sheet 102 is attached to the upper part of the upper housing 104 to shield light from the outside. Further, a serial number sheet 132 and a drive key 136 for identifying the exposure apparatus 100 are attached to the lower surface of the lower housing in the drawing, and a SELFOC lens array (registered trademark) 138 is provided in the groove of the lower housing 130. Is fixed.

  The upper reflector 106 is configured so as to surround the light guide element 108, reflect the light from the LED 120, and selectively emit light from the protrusion 110 of the light guide element 108. The reflection mirror 112 reflects the light from the LED 120 into the light guide element 108, and the slit portion 116 of the lower reflection plate 114 has a function of the protrusion 110 of the light guide element 108. The liquid crystal shutter array 118 is positioned and fixed to the lower housing 130 while the optical path is adjusted by adjusting screws 124 and 126. The LED 120 is a light source of the exposure apparatus 100 and includes an R light LED, a G light LED, and a B light LED. The liquid crystal shutter array 118 is connected to a signal line 122 for controlling the driving time of each driving pixel of the liquid crystal shutter array 118 and for applying a current to the LED 120. The terminal of the signal line 122 is at the upper and lower housings. It extends from between 104 and 130 to the outside of the exposure apparatus 100. In the drawing, reference numeral 128 denotes a bearing for movement of the exposure apparatus 100. The drive key 136 is a member for determining the drive timing of the exposure apparatus 100 together with a sensor (not shown) and the like when the exposure apparatus 100 is driven by a ball screw and a bearing 128 (not shown). The SELFOC lens array 138 is an optical element in which a large number of cylindrical lenses are arranged so as to overlap in the longitudinal direction and forms an erecting equal-magnification image.

  As shown in FIG. 5, in the upper part of the light guide element 108 in the drawing, each color light from the LED 120 is concentrated in the direction of the liquid crystal shutter array 118 arranged immediately below the light guide element 108 in the figure. The scattering film 107 is formed along the longitudinal direction of the light guide element 108. The scattering film 107 is formed by applying a white scattering substance in a straight line.

  FIG. 6 shows a cross-sectional view of the liquid crystal shutter array 118 shown in FIGS. In FIG. 6, a transparent common electrode 411 made of a transparent ITO thin film or the like is provided on the entire lower surface of the upper substrate 401 and covered with an alignment film 413 such as polyimide. A fine transparent pixel electrode 416 is provided on the upper portion of the lower substrate 402 and is covered with an alignment film 415. Further, the outer circumferences of both substrates are bonded by a sealing material 403 made of epoxy resin or the like, and liquid crystal 414 is filled between alignment films 413 and 415 of both substrates. Note that. The thickness of the liquid crystal 414 is set to 5 μm. Further, the transparent common electrode 411 is covered with a light shielding layer 412 made of a chromium material or the like, and a slit is provided at a location of the light shielding layer 412 corresponding to the transparent pixel electrode 416 so that only the portion can emit light. It is configured to pass through. Further, polarizing plates 410 and 417 are provided on the outer sides of both substrates. Further, the liquid crystal 414 is operated in, for example, an STN mode with a twist angle of 240 °, and the two polarizing plates 410 and 417 can cross the polarization axes at an angle corresponding to this.

In addition, the transparent common electrode 411 and the transparent pixel electrode 416 form individual drive pixels 420 constituting a liquid crystal shutter array in a straight line. Here, as described with reference to FIG. 3, the size of the individual drive pixels 420 constituting the liquid crystal shutter array is as follows: length (b) 150 μm (or 200 μm), width (e) 76 μm, and pitch (f) 100 μm. is there.

  FIG. 7 is a view for explaining an optical path from the LED 120 to the CCD sensor 230 included in the exposure apparatus 100. As shown in FIG. 7, the light emitted from the LED 120 is incident on the light guide element 108 in the longitudinal direction of the light guide element 108, reflected downward by the scattering film 107, and from the lower protrusion 110 of the light guide element 108. The light is emitted toward the liquid crystal shutter array 118. Further, the light whose transmission is controlled by each driving pixel 420 of the liquid crystal shutter array 118 is imaged on the CCD sensor 230 by the SELFOC array 138. The exposure apparatus 100 is provided with three color LEDs, and each color light emitted from each color LED is imaged on the CCD sensor 230 according to the optical path shown in FIG.

  A procedure for determining an applied current value of an LED incorporated as a light source in the exposure apparatus 100 will be described with reference to FIGS.

  FIG. 8 is a flowchart showing a procedure for determining an applied current value of the LED.

When the adjustment of the exposure apparatus is started, the exposure apparatus 100 to be adjusted is set at a predetermined location of the adjustment apparatus 200, and the signal line 122 is inserted into the IF 240. Thereafter, an adjustment start instruction is transmitted from the PC 300 to the CPU 210 via the bus line 260 by the operator, and adjustment is started. Hereinafter, the procedure described in FIG. 8 is executed in accordance with the system control software stored in the PC 300 while the PC 300 and the CPU 210 cooperate with each other.

  First, a predetermined first current value (reference current value) is applied from the LED lighting control circuit 242 to one LED element of the LED 120 of the exposure apparatus 100 (in this example, an R light LED), and R Only the light LED element is turned on (step 801). As described above, the exposure apparatus 100 has three color LED elements (for R light, G light, and B light), but the current value is determined for each LED element. The liquid crystal shutter array 118 of the exposure apparatus 100 outputs a signal for controlling the aperture of all the pixels at an intermediate drive gradation level from the liquid crystal shutter drive circuit 244. This is because the density of the photosensitive material changes greatly due to a slight change in the amount of light at the intermediate gradation level, which greatly affects the image quality. In the present embodiment, the optimum adjustment is realized by adjusting the light quantity of the LED at an intermediate gradation level that greatly affects the image quality.

Next, the spectroscopic sensor 220 is set by the sensor control circuit 222, and the peak wavelength λp of the light emitted from the LED element is detected by the spectroscopic sensor 220 and the detection circuit 224 (step 802). The light emitted from the LED element passes through the liquid crystal shutter array 118 and reaches the spectroscopic sensor 220 as shown in FIG. Therefore, when the liquid crystal 414 of the liquid crystal shutter array 118 has a property of absorbing a specific wavelength, the peak wavelength cannot be accurately detected. Therefore, when the absorption wavelength of the liquid crystal 414 and the peak wavelength of the LED element are approximate, the peak wavelength λp is not detected, but the half-value wavelength λ ₁ on the short wavelength side and the half-value wavelength λ ₂ on the long wavelength side are detected. It is preferable to obtain the peak wavelength λp from the peak wavelength λp = (λ ₁ + λ ₂ ) / 2.

  FIG. 9 shows the spectral characteristic 900 of the G-color LED element that is considered to be particularly susceptible to passing through the liquid crystal, the ideal spectral characteristic 910 before passing through the liquid-crystal shutter array 118 of the G-color LED element, and the liquid crystal shutter. An example of the absorption wavelength characteristic 920 of the liquid crystal used in the array 118 is shown. In FIG. 9, the horizontal axis indicates the wavelength λ (nm), and the vertical axis indicates the relative light quantity L.

As shown in FIG. 9, the spectral characteristic 900 of the G-color LED element has changed so as to have _two peaks P ₁ and P ₂ on its upper part by passing through the liquid crystal or the like. As described above, this is considered to be due to absorption at a specific portion 922 in the absorption wavelength characteristic 920 of the liquid crystal. In addition, there is a scattering film 107 or the like that affects the spectral characteristics of the LED element. Especially in this case, it selects the wavelength P ₁ having a maximum light amount of the plurality of peak wavelengths, the value wavelength lambda ₁ and the wavelength P ₁ of the short wavelength side having a half of the amount of light wavelengths P ₁ It is preferable to detect the half wavelength λ ₂ on the long wavelength side having a light quantity of ½, and obtain the peak wavelength λp by the peak wavelength λp = (λ ₁ + λ ₂ ) / 2 (that is, the average of the half value wavelengths). From the fact that the peak wavelength λp thus determined and the peak of the ideal spectral characteristic 910 substantially coincide, it can be understood that the peak wavelength λp determined by such a method is accurate.

When the spectral characteristics of the LED element have a plurality of peak wavelengths, the half-value wavelengths λ ₁ and λ ₂ are set using wavelengths other than the wavelength P ₁ having the maximum light amount (for example, the second peak wavelength P ₂ ). When the peak wavelength λp ′ is detected and the peak wavelength λp ′ is obtained, the deviation between the obtained peak wavelength λp ′ and the peak of the ideal spectral characteristic 910 is larger than the peak wavelength λp using the _first peak wavelength P1. Has been confirmed by experiments.

  Next, the table driving circuit 214 moves the table 270 so that the CCD sensor is set at the light receiving position, and the CCD control circuit 232 sets the CCD sensor. The received light amount from all the light receiving elements 280 of the CCD sensor 230 is detected by the received light amount detection circuit 234, integrated by the integration circuit 236, converted into a digital signal, and input to the CPU 210. The CPU 210 sets the average value of the received light amounts of all the detected light receiving elements 280 as the light amount of the LED elements (step 803).

  Next, a second current value to be applied to the LED element from the LED lighting control circuit 242 is determined so that the light amount measured in step 803 becomes a predetermined reference light amount (step 804). This is because the bit of the digital signal input from the integrating circuit 236 to the CPU 210 when the light amount is to be accurately measured even when the light amount of the LED element is extremely large or extremely small due to individual differences of the LED elements. This is because it is necessary to set a large number, the processing time becomes long, and the processing process becomes complicated. By setting the predetermined reference light amount, it is possible to measure the light amount with high accuracy with a small number of bits.

Next, using the peak wavelength (λp) or the half-value wavelength (λ ₁ and λ ₂ ) measured in step 802 and the light amount measured in step 803 or 804, a preset spectral distribution profile is corrected to produce an LED. A first profile (first LED characteristic) for the device is created (step 805). FIG. 10 shows an example of a first profile 1000 having a peak wavelength λp and a relative light quantity L1 (a value defining the measured light quantity). In FIG. 10, the horizontal axis indicates the wavelength λ (nm), and the vertical axis indicates the relative light quantity L. As described above, the same profile is obtained for the half-value wavelengths λ ₁ and λ ₂ . The preset spectral distribution profile is created in advance based on the measurement results of a suitable plurality of LEDs.

  Next, the first profile created in step 805 is corrected according to the spectral sensitivity characteristic of the sensor, and a second profile (second LED characteristic) is created (step 806). FIG. 11 shows an example of the second profile 1100 corrected according to the spectral sensitivity characteristic 1600 of the CCD sensor 230. As shown in FIG. 16, the sensor spectral sensitivity characteristic 1600 changes such that the sensitivity increases as the wavelength increases, and therefore the sensor sensitivity changes when the peak wavelength of the LED changes. However, the second profile 1100 is always corrected so as to have the same relative light amount. The second profile 1100 is obtained by multiplying the relative sensitivity S and the relative light quantity L for each wavelength λ. In this example, calculation was performed for a range of 360 nm to 780 nm every 1 nm. In FIG. 11, the horizontal axis indicates the wavelength λ (nm), and the vertical axis indicates the relative light quantity L and the relative sensitivity S.

  Next, the second profile created in step 806 is corrected in accordance with the spectral sensitivity characteristic of the photosensitive material to create a third profile (third LED characteristic) (step 807). FIG. 12 shows an example of the third profile 1200 corrected in accordance with the R color spectral sensitivity characteristic 1511 of the photosensitive material. In FIG. 12, the horizontal axis indicates the wavelength λ (nm), and the vertical axis indicates LR (relative light quantity × relative sensitivity). In FIG. 12, since it relates to the R color LED element, correction is performed according to the R color spectral sensitivity characteristic 1511 of the photosensitive material. However, for the G color LED element, the G color spectral sensitivity characteristic 1512 of the photosensitive material. The B color LED element is corrected using the B color spectral sensitivity characteristic 1513 of the photosensitive material. Here, an R color LED element having a peak wavelength on the long wavelength side with respect to the R color spectral sensitivity characteristic 1511 of the photosensitive material was selected. This is to avoid mixing with the G color spectral sensitivity characteristics of the photosensitive material on the short wavelength side.

  The third profile 1200 is obtained by multiplying the R color spectral sensitivity characteristic 1511 of the photosensitive material and the second profile 1100 for each wavelength λ. In this example, calculation was performed for a range of 360 nm to 780 nm every 1 nm. Note that the third profile 1200 indicated by hatching in FIG. 12 corresponds to the exposure amount Q related to the R color development of the photosensitive material. Another example of the third profile obtained for a plurality of LEDs having different peak wavelengths is shown in FIG. As shown in FIG. 13, the third profile created as in 1300 to 1306 changes according to the difference in the emission peak wavelength of each LED. The profile indicated by 1200 in FIG. 13 is obtained in FIG.

  Next, a third current value applied to the LED is determined so that the area of the third profile 1200 becomes a predetermined value (step 808). For example, by increasing the current value applied to the LED, the second profile 1100 changes to become 1100 ′ (see FIG. 14), whereby the third profile 1200 becomes 1400 (see FIG. 14). ). The third current value is determined so that the area of the third profile that changes in response to the change in the current value applied to the LED becomes a predetermined value (indicated by hatching in FIG. 14).

  Next, the determined third current value is stored in the LED control condition memory (step 809), and the procedure ends. Note that an appropriate memory chip or the like may be provided in the exposure apparatus 100 in advance, and the determined third current value may be stored therein. Furthermore, when the exposure apparatus 100 is used, the third current value may be read from the memory chip.

  As described above, the area of the third profile corresponds to the exposure amount Q related to the color development of the photosensitive material. Therefore, by setting this value to a predetermined value, the individual difference of the LEDs and the sensor spectral sensitivity distribution can be obtained. Regardless, it is possible to determine an LED applied current value that can provide a constant density on the photosensitive material.

  In this embodiment, an example in which the applied current value of an LED incorporated in an exposure apparatus that is separable from the image forming apparatus is determined. However, the present invention is applied to an exposure apparatus that is configured integrally with the image forming apparatus. The present invention can also be applied to the case of determining the applied current value of the incorporated LED. Furthermore, the present invention can also be applied to an LED before being incorporated in an exposure apparatus. However, since various conditions may be changed by incorporating the LED into the exposure apparatus, it is preferable to determine the applied current value of the LED after incorporation into the exposure apparatus.

It is a conceptual diagram which shows an example of the system for adjusting the exposure apparatus concerning this invention. It is a figure which shows the external appearance of the adjustment system shown in FIG. It is a figure which shows an example of the CCD sensor used for an adjustment system. It is a disassembled perspective view which shows an example of exposure apparatus. It is sectional drawing of the exposure apparatus shown in FIG. It is sectional drawing of the liquid-crystal shutter used for the exposure apparatus shown in FIG. It is a figure for demonstrating the optical path in an adjustment system. It is a flowchart for determining the applied current value of LED. It is a figure which shows an example of the spectral characteristic of LED. It is a figure which shows the example of a 1st LED characteristic. It is a figure which shows the example of the 2nd LED characteristic. It is a figure which shows the example of a 3rd LED characteristic. It is a figure which shows the example of the other 3rd LED characteristic. It is a figure for demonstrating correction | amendment of a 3rd LED characteristic. It is a figure which shows an example of the spectral characteristic of LED, and the spectral sensitivity characteristic of a photosensitive material. It is a figure which shows the spectral sensitivity characteristic of a sensor.

Explanation of symbols

100 ... Exposure device 120 ... LED
200 ... Adjustment device 210 ... CPU
212 ... LED control condition memory 220 ... Spectral sensor 230 ... CCD sensor 242 ... LED control circuit 300 ... PC

Claims (6)

In an exposure apparatus manufacturing method for exposing a photosensitive material using an LED as a light source,
Applying a reference current value to the LED to emit light, and measuring a spectral characteristic and a light amount of light emitted from the LED; and
Obtaining a first LED characteristic based on the spectral characteristic and the light amount;
Correcting the first LED characteristic based on a sensitivity characteristic of a sensor for measuring the light amount to obtain a second LED characteristic;
Correcting the second LED characteristic based on the wavelength sensitivity characteristic of the photosensitive material to obtain a third LED characteristic;
Determining a set current value so that the third LED characteristic becomes a reference characteristic ,
The spectral characteristics include a first half-value wavelength on the short wavelength side having a light amount that is 1/2 of a wavelength having a maximum light amount of light emitted from the LED, and a light amount that is 1/2 of a wavelength having the maximum light amount. It is a virtual peak wavelength determined by averaging with the second half-value wavelength on the long wavelength side
An exposure apparatus manufacturing method characterized by the above.   The method of manufacturing an exposure apparatus according to claim 1, further comprising a step of correcting the reference current value so that the light amount becomes a reference light amount.   The exposure apparatus manufacturing method according to claim 1, wherein the first LED characteristic is obtained by correcting predetermined LED profile data based on the spectral characteristic and the reference light amount. The said LED is each LED for R light, G light, and B light, The manufacturing method of the exposure apparatus as described in any one of Claims 1-3 . 5. The exposure apparatus manufacturing method according to claim 1 , wherein the LED is an LED for R light, and the wavelength sensitivity characteristic of the photosensitive material is a wavelength sensitivity characteristic on a long wavelength side. An exposure apparatus that exposes a photosensitive material using an LED as a light source,
Applying a reference current value to the LED to emit light, and measuring a spectral characteristic and a light amount of light emitted from the LED; and
Obtaining a first LED characteristic based on the spectral characteristic and the light amount;
Correcting the first LED characteristic based on a sensitivity characteristic of a sensor for measuring the light amount to obtain a second LED characteristic;
Correcting the second LED characteristic based on the wavelength sensitivity characteristic of the photosensitive material to obtain a third LED characteristic;
Determining a set current value so that the third LED characteristic becomes a reference characteristic,
The spectral characteristics include a first half-value wavelength on the short wavelength side having a light quantity that is ½ of a wavelength having a maximum light quantity of light emitted from the LED, and a light quantity that is ½ of a wavelength having the maximum light quantity. An exposure apparatus wherein the LED is adjusted by an adjustment method, which is a virtual peak wavelength obtained by averaging with a second half-value wavelength on the long wavelength side .

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