JP2006116768A - Luminescent device and brightness correction method for line head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a luminance correction method for a light emitting device and a luminance correction method for a line head which can correct a luminance variation of a light emitting element without providing a complicated circuit or the like and obtain a uniform light amount distribution.
A luminance correction method according to the present invention is a luminance correction method for a light-emitting device in which a plurality of light-emitting elements are arranged in a plane, and measures the light amount distribution of the light-emitting device by turning on the light-emitting elements. A step of determining aging luminance (FIG. (B)) which is light emission luminance at the time of aging of each light emitting element based on the obtained light quantity distribution ((a) diagram), and And aging by turning on each light emitting element.
[Selection] Figure 6

Description

  The present invention relates to a luminance correction method for a light emitting device and a line head.

  A line printer (image forming apparatus) is known as an electrophotographic printer. In this line printer, devices such as a charger, a line-shaped printer head (line head), a developing device, and a transfer device are arranged close to each other on the peripheral surface of a photosensitive drum serving as an exposed portion. That is, an electrostatic latent image is formed on the peripheral surface of the photosensitive drum charged by the charger by selective light emission operation of a light emitting element provided in the line head, and this latent image is formed. It is developed with toner supplied from a developing device, and the toner image is transferred onto a sheet by a transfer device.

  By the way, a light emitting diode or the like is generally used as the light emitting element of the line head as described above. However, this has a problem that it is extremely difficult to arrange thousands of light emitting points with high accuracy. Therefore, in recent years, an image forming apparatus including a light emitting element array using an organic electroluminescent element (organic EL element) capable of accurately forming a light emitting point as a light emitting element as an exposure unit has been proposed (for example, Patent Documents). 1).

  Moreover, in the electrophotographic line printer as described above, the radiation from the line head is usually used to convert the SELFOC (registered trademark) lens array (trade name of Nippon Sheet Glass; hereinafter, SELFOC (registered trademark) lens to SL, A system in which an image is formed on a photosensitive drum by passing through a SELFOC (registered trademark) lens array (referred to as an SL array) and exposed is employed. The SL array enables a wide range of images to be formed by a configuration in which a large number of cylindrical SL elements for erecting equal-magnification images are arranged.

  By the way, the image made by the SL array is formed by overlapping the images made by each SL element (erecting equal-magnification image formation), and the SL element has a light quantity distribution that halves football. is doing. Therefore, in the SL array, there is a problem that periodic light amount unevenness occurs with the arrangement pitch of each SL element. If such periodic light amount unevenness exists, the line head and the SL array are combined. When they are combined, the uniformity of the light intensity in the main scanning direction is deteriorated due to the unevenness of the light amount of the SL array, the exposure accuracy is lowered, and the quality of the obtained print is impaired.

Therefore, as a technique for removing periodic light amount unevenness due to the imaging principle of the SL array, it has been proposed to correct the light amount periodic unevenness by drive control of the light emitting element (see, for example, Patent Document 2). In this method, correction data derived based on the light amount unevenness of the line head measured in advance is held in a memory, and drive data of the light emitting element is corrected with the correction data.
JP 11-198433 A JP-A-9-314897

However, in such a method of performing correction by drive control of the light emitting element, there is a problem that the configuration of the drive circuit and the control system becomes complicated and requires cost.
The present invention has been made in view of the above-described problems of the prior art, and is a light-emitting device that corrects variations in luminance of light-emitting elements without providing a complicated circuit or the like and obtains a uniform light amount distribution. It is an object of the present invention to provide a luminance correction method and a line head luminance correction method.

In order to solve the above-mentioned problem, the present invention provides a luminance correction method for a light-emitting device in which a plurality of light-emitting elements are arranged in a plane, and includes a step of lighting the light-emitting elements and measuring a light amount distribution of output light. And a step of determining an aging luminance which is a light emission luminance at the time of aging of each light emitting element based on the obtained light amount distribution, and a step of performing aging by lighting each light emitting element at the aging luminance. A luminance correction method for a light emitting device is provided.
In this brightness correction method, brightness correction is performed in an aging process performed after the light emitting device is assembled. That is, it is intended to obtain a light-emitting device having a uniform light amount distribution by actively utilizing the luminance reduction due to continuous lighting of the light-emitting elements to reduce the variation in the amount of light in the entire light-emitting device. According to such a luminance correction method, it is not necessary to provide a luminance correction circuit or arithmetic processing in the drive circuit or control system for driving the light emitting element, so that the cost can be reduced by simplifying the configuration. Can do.

  In the light emitting device of the present invention, it is preferable that the aging luminance is set to a higher luminance as the light emitting element has a larger light amount in the light amount distribution. In other words, the light intensity reduction range of the light emitting elements with high light emission brightness is relatively increased, and the light intensity reduction of the light emitting elements with low light emission brightness is suppressed, so that the light quantity distribution can be made uniform while maintaining the overall light quantity. Can be planned.

  In the light emitting device of the present invention, the aging luminance may be larger than the light emission luminance during normal operation of the light emitting element. According to this brightness correction method, the speed of decreasing the brightness during the aging process can be increased, so that the aging process can be completed in a short time, and the light emitting device can be efficiently manufactured and the brightness can be adjusted. The “emission luminance during normal use” is the emission luminance in the range used for the operation in the actual usage environment of the light emitting device. For example, if the light emitting device is used in an image display device, The light emission luminance in a range used in the image display operation.

Next, according to the brightness correction method for a line head of the present invention, a line head including a plurality of light emitting elements arranged in a plane and light output from the line head are coupled to an exposed portion via a lens element. A brightness correction method for a line head that can be applied to a line head module including a lens array for imaging, the step of turning on the light emitting element and measuring a light amount distribution of light output through the lens array; A step of determining an aging luminance which is a light emission luminance at the time of aging of each light emitting element based on the obtained light quantity distribution; and a step of performing an aging by turning on each light emitting element at the aging luminance. It is characterized by that.
According to this brightness correction method, in a line head used in an image forming apparatus or the like, it is possible to obtain a uniform light amount distribution in the arrangement direction of the light emitting elements, thereby improving the resolution and the image quality of the image forming apparatus or the like. be able to.

  In the luminance correction method for a line head according to the present invention, it is preferable that the aging luminance is set to a higher luminance as the light emitting element is located at a position where the light amount is larger in the light amount distribution. That is, in the light emitting element arranged at the position where the light amount of the output light through the lens array becomes large, the luminance decrease width is relatively large, and the luminance decrease of the light emitting element arranged at the position where the light amount becomes small is relatively Thus, the light quantity distribution can be made uniform while maintaining the light quantity as a whole. According to this luminance correction method, the luminance is corrected based on the light amount distribution of the output light through the lens array, so that the variation in the light amount caused by the lens array can also be corrected, and the structure and assembly accuracy of the line head module can be improved. Regardless of this, it is possible to achieve uniform light quantity distribution.

  In the brightness correction method for a line head according to the present invention, it is preferable that the aging brightness is larger than the light emission brightness during normal operation of the light emitting element. According to this brightness correction method, the aging of the line head can be performed in a short time.

The present invention provides an image display device including a light emitting device whose luminance is corrected by the luminance correction method for a light emitting device described above. According to this configuration, there is provided an image display device including a display unit having uniform brightness mainly including a light emitting device having a uniform light amount distribution.
The present invention provides an image forming apparatus including a line head whose luminance is corrected by the line head luminance correction method described above. According to this configuration, there is provided an image forming apparatus capable of forming a high-quality and high-resolution image without blurring by the line head having a uniform light amount distribution.

  Embodiments of the present invention will be described below with reference to the drawings. In each drawing referred to below, the dimensions and the like of each component are appropriately changed and displayed for easy understanding of the drawing.

(Line head module)
First, a line head module including a line head to which the luminance correction method according to the present invention can be applied will be described. This line head module is used as an exposure unit of an image forming apparatus.
FIG. 1 is a side sectional view of a line head module according to an embodiment. The line head module 101 of the present embodiment includes a line head 1 in which a plurality of organic EL elements are arranged and a lens array 31a (lens array) in which lens elements 31a for imaging the light from the line head 1 at an erecting equal magnification are arranged. ) 31 is supported by the head case 52 at a predetermined interval. The line head 1 and the SL array array 31 are held in the head case 52 in an aligned state, whereby the SL array 31 allows the light from the line head 1 to be erecting to a photosensitive drum, which will be described later. It is designed to form an image.

(Line head)
FIG. 2 is a diagram schematically showing the line head. The line head 1 drives a light emitting element array (light emitting part line) 3A in which a plurality of organic EL (electroluminescence) elements 3 are arranged on a long and thin rectangular element substrate 2, and the organic EL element 3. A drive element group including the drive elements 4 and a control circuit group 5 that controls the drive of these drive elements 4 (drive element groups) are integrally formed. In FIG. 2, the light emitting element array 3 </ b> A is shown as one organic EL element 3. In that case, the pitch of the organic EL elements 3 in the element arrangement direction of the line head 1 can be reduced, and the resolution of the image forming apparatus described later can be improved.

The organic EL element 3 has a configuration in which at least an organic light emitting layer is sandwiched between a pair of electrodes, and emits light by supplying a current from the pair of electrodes to the organic light emitting layer. A power supply line 8 is connected to one electrode of the organic EL element 3, and a power supply line 7 is connected to the other electrode via a drive element 4. The drive element 4 is composed of a switching element such as a thin film transistor (TFT) or a thin film diode (TFD). When a TFT is adopted as the drive element 4, the power supply line 8 is connected to the source, and the control circuit group 5 is connected to the gate. The energization of the organic EL element 3 is controlled by the switching operation of the drive element 4 based on the control signal input from the control circuit group 5. Further, the driving element 4 and the control circuit group 5 can be configured by a method of externally attaching a driver IC without forming them integrally on the substrate. The driver IC is mounted directly on the element substrate 2, for example, when the element substrate is made of glass, COG (Chip On Glass) mounting, after mounting the driver IC on the flexible substrate, there is a method of connecting the element substrate and the flexible substrate, etc. .
The detailed structure and manufacturing method of the organic EL element 3 and the driving element 4 will be described later. Further, in this line head 1, the organic EL element 3 is used as the EL element, but it goes without saying that an inorganic EL element may be used instead.

(SL array)
FIG. 3 is a perspective view of the SL array. This SL array 31 is configured by arranging (arranging) two staggered SL elements 31a having the same configuration as a convergent rod lens (for example, SELFOC (registered trademark) lens manufactured by Nippon Sheet Glass Co., Ltd.). . The SL elements 31a arranged in a zigzag shape in plan view are fixed by a black silicone resin 32 filled in a gap, and are supported by a frame 34 that integrally surrounds them.

  The SL element 31a has a parabolic refractive index distribution from the center to the periphery. For this reason, the light incident on the SL element 31a travels while meandering in the constant cycle. Therefore, if the length of the SL element 31a is adjusted, an image can be formed upright at an equal magnification. In the SL element 31a that forms an erecting equal-magnification image in this way, images formed by adjacent SL elements 31a can be superimposed, and a wide range of images can be obtained. Therefore, the SL array 31 shown in FIG. 3 can accurately form light from the entire line head 1 on the surface to be exposed.

(Line head brightness correction method)
Next, a method of correcting the luminance of the line head having the above configuration will be described with reference to FIGS. 4 and 5 are explanatory diagrams showing the state of the transmitted light amount according to the positional relationship between the line head 1 and the SL array 31, and FIG. 6 is an explanatory diagram of the luminance correction method of the present embodiment.

  As described above, in order to improve the exposure accuracy in the image forming apparatus provided with the line head module 101, it is important to make the amount of light emitted from the line head module 101 uniform. It is required to suppress variations in the amount of light output via 31a within 3%. However, in the line head module 101 having the above-described configuration, the light amount distribution varies greatly depending on the arrangement form of the line head 1 and the SL array 31. Hereinafter, a description will be given with reference to FIGS.

4A is a plan configuration diagram showing a state in which the line head 1 is arranged in alignment with the center line 31s of the SL array 31, and FIG. 4B is a longitudinal direction of the head in the arrangement shown in FIG. It is a figure which shows typically light quantity distribution of the (left-right direction). On the other hand, FIG. 5A is a plan configuration diagram showing a state in which the line head 1 is arranged shifted from the center line 31s of the SL array 31 in the width direction (downward direction) of the SL array, and FIG. FIG. 6 is a diagram schematically showing a light amount distribution in the longitudinal direction of the head in the arrangement shown in FIG.
As is clear from the comparison between FIG. 4B and FIG. 5B, not only the variation in the amount of light but also the period changes depending on the arrangement form of the line head 1 and the SL array 31. That is, the light amount distribution shown in FIG. 5B changes in light amount at a cycle about twice that of the distribution shown in FIG. 4B, and the light amount displacement width d2 (maximum value and minimum light amount). The difference from the value is also larger than the displacement width d1 shown in FIG.

  As described above, even when the light quantity variation of the line head 1 itself is corrected and uniform light is incident on the SL array 31, the light emitted from the line head module 101 is periodically as shown in FIGS. The distribution accuracy is greatly affected by the alignment accuracy between the line head 1 and the SL array 31. The luminance correction method according to the present embodiment corrects the light amount variation caused by the structure of the SL array 31 and the light amount variation caused by the alignment with the line head 1 without complicating the circuit and the control system. To do.

  FIG. 6 is a diagram for explaining each step in the luminance correction method of the present embodiment. In the luminance correction method of the present embodiment, first, light emitted from the SL array 31 is operated by operating the light emitting element array 3A provided in the line head 1 of the assembled line head module 101 with the same current or the same voltage. Measure the strength. FIG. 6A is a schematic diagram showing a light amount distribution in the longitudinal direction of the line head module 101 obtained by the light amount measurement. As shown in the figure, in the assembled line head module 101 that has not been subjected to luminance correction, the light amount distribution in which the light amount distribution of the light emitting element array 3A and the periodic transmittance distribution caused by the SL array 31 are superimposed. Observed.

  Next, aging luminance corresponding to each organic EL element 3 constituting the line head 1 is determined based on the light amount distribution obtained in the above process. This aging luminance is the light emission luminance of the organic EL element 3 in the aging process of the line head module 101 in the subsequent stage. As shown in FIG. 6B, the aging luminance determined in this way shows the same tendency (distribution) as the light amount distribution shown in FIG. 6A for the entire line head 1 (light emitting element array 3A). However, in the light amount distribution of the line head module 101 measured in the previous process, the aging luminance of the organic EL element 3 corresponding to the position where the light intensity is relatively high is set higher, and conversely The aging luminance of the organic EL element 3 corresponding to the position where the intensity is small is set relatively low.

  Next, each organic EL element 3 is caused to emit light at the aging luminance determined in the above process, and aging is performed for a predetermined time. At that time, the luminance at the time of aging processing of the organic EL element 3 (referred to as a high-luminance element for convenience of explanation) corresponding to the position where the light intensity is relatively large in the light quantity distribution measured first is relatively The difference between the brightness of the organic EL element 3 (referred to as a low brightness element for convenience of explanation) corresponding to the position of low light intensity during the aging process is set to be larger than that during the first measurement. Therefore, the brightness of the high brightness element can be selectively reduced by the aging process. Accordingly, when the light emitting element array 3A of the line head 1 is driven with a constant current or a constant voltage after performing such an aging process, the light emission luminance distribution is as shown in FIG. The shape shown in FIG. 5 is substantially inverted in the vertical direction in the figure. Then, when the light output from the light emitting element array 3A having such a light emission luminance distribution is emitted through the SL array 31, as shown in FIG. 6D, the light emitting element array 3A is substantially flat in the arrangement direction. A light amount distribution can be obtained.

  As described above, according to the brightness correction method of the line head of this embodiment, the light amount distribution of the line head module 101 can be corrected in the aging process performed after the assembly of the line head module 101, and a uniform light amount distribution can be obtained. Therefore, it is possible to provide the line head module 101 that can be manufactured at low cost without complicating the drive circuit and the control system as in the case of light emission luminance correction of each organic EL element 3 by the drive circuit and the control system. .

  The luminance correction method according to the present embodiment can be used regardless of the drive mode of the line head 1, but the line head is configured to perform gradation control by changing the light emission luminance by the current / voltage supplied to the organic EL element 3. Compared with the case of applying, each organic EL element 3 is driven at a constant luminance, and when applied to a line head in which gradation control is performed by pulse width (light emission time), a particularly great effect is obtained. That is, in the luminance correction method of the present invention, the emission luminance for a predetermined current / voltage value is adjusted. Therefore, if the emission luminance at the time of use is fixed, the emission luminance can be adjusted more accurately. And the uniformity of the amount of light can be improved.

  However, it goes without saying that the correction method of the present embodiment may be used for a line head in which gradation control is performed by luminance change depending on current / voltage values, and the luminance of the organic EL element 3 is used in a drive circuit and a control system. You may apply to the line head provided with the means to correct | amend. Even when this type of line head is used, a uniform light amount distribution in which the light amount variation of the line head 1 and the transmittance distribution of the SL array 31 are compensated can be obtained. The circuit size can be reduced and the cost can be reduced.

  The processing time in the aging process, the drive current and drive voltage of each organic EL element 3 are preferably set as appropriate according to the current / voltage characteristics and the element deterioration characteristics of the organic EL elements 3, If the light emission luminance of each organic EL element 3 is made larger than the light emission luminance during normal use, the luminance change of the organic EL element 3 increases, and the aging processing time can be shortened.

  In the present embodiment, the case where the light amount distribution of the line head module 101 for the image forming apparatus is made uniform using the line head luminance correction method according to the present invention has been described. However, the technical scope of the present invention is related to the line. The present invention is not limited to the head, and can be applied to all light emitting devices in which light emitting elements are arranged in a plane. For example, the present invention may be applied to a light emitting device constituting a display body of an image display device. Of course.

(Detailed configuration of line head)
Hereinafter, a detailed configuration of the organic EL element, the driving element, and the like in the line head used in the above embodiment will be described with reference to FIGS. FIG. 7A is a partial cross-sectional configuration diagram of the line head 1, and FIG. 7B is a plan configuration diagram illustrating the organic EL element 3 and the drive element 4.

  In the case of a so-called bottom emission type in which the light emitted from the light emitting layer 60 is emitted from the pixel electrode 23 side, the light emitting light is extracted from the element substrate 2 side. Therefore, the element substrate 2 is transparent or translucent. Things are adopted. For example, glass, quartz, resin (plastic, plastic film) and the like can be mentioned, and a glass substrate is particularly preferably used.

In the case of a so-called top emission type in which the light emitted from the light emitting layer 60 is emitted from the cathode (counter electrode) 50 side, the emitted light is extracted from the sealing substrate side that is the opposite side of the element substrate 2. Therefore, either a transparent substrate or an opaque substrate can be used. Examples of the opaque substrate include a thermosetting resin and a thermoplastic resin in addition to a ceramic sheet such as alumina and a metal sheet such as stainless steel that has been subjected to an insulation treatment such as surface oxidation.
In the present embodiment, a bottom emission type is adopted, and therefore transparent glass is used for the element substrate 2.

  On the element substrate 2, a circuit unit 11 including a driving TFT 123 (driving element 4) connected to the pixel electrode 23 is formed, and an organic EL element 3 is provided thereon. The organic EL element 3 includes a pixel electrode 23 functioning as an anode, a hole transport layer 70 for injecting / transporting holes from the pixel electrode 23, a light emitting layer 60 made of an organic EL material, and a cathode 50 in this order. It is configured by being formed.

  Here, FIG. 7B shows the organic EL element 3 and the driving TFT 123 (driving element 4) in a schematic view corresponding to FIG. In FIG. 5B, the power line 7 is connected to the source / drain electrodes of the driving element 4, and the power line 8 is connected to the cathode 50 of the organic EL element 3. In the organic EL element 3 having such a configuration, the holes injected from the hole transport layer 70 and the electrons from the cathode 50 are combined in the light emitting layer 60 as shown in FIG. By doing so, it emits light.

In this embodiment, an inorganic partition wall 25 made of a lyophilic insulating material such as SiO ₂ is formed on the pixel electrode 23, and an opening 25 a is formed in the inorganic partition wall 25. Since the inorganic partition wall 25 is formed using an insulating material, in the functional layer provided so as to face the opening 25a as will be described later, no current flows through the portion covered with the inorganic partition wall 25, Therefore, the light emitting region, that is, the light emitting area is determined by the opening 25 a of the inorganic partition wall 25.

The pixel electrode 23 that functions as an anode is formed of a transparent conductive material, particularly in the case of a bottom emission type, and specifically, ITO is preferably used.
As a material for forming the hole transport layer 70, in particular, a dispersion of 3,4-polyethylenediosithiophene / polystyrene sulfonic acid (PEDOT / PSS), that is, 3,4-polyethylenedioxy in polystyrene sulfonic acid as a dispersion medium. A dispersion in which thiophene is dispersed and further dispersed in water is preferably used.
In addition, as a forming material of the positive hole transport layer 70, various things can be used, without being limited to the said thing. For example, a material obtained by dispersing polystyrene, polypyrrole, polyaniline, polyacetylene or a derivative thereof in an appropriate dispersion medium such as the aforementioned polystyrene sulfonic acid can be used.

  As a material for forming the light emitting layer 60, a known light emitting material capable of emitting fluorescence or phosphorescence is used. In the present embodiment, for example, a light emitting layer whose emission wavelength band corresponds to red is adopted. Of course, a light emitting layer whose emission wavelength band corresponds to green or blue may be adopted.

  Specific examples of the material for forming the light emitting layer 60 include (poly) fluorene derivative (PF), (poly) paraphenylene vinylene derivative (PPV), polyphenylene derivative (PP), polyparaphenylene derivative (PPP), and polyvinylcarbazole (PVK). ), Polythiophene derivatives, and polysilanes such as polymethylphenylsilane (PMPS) are preferably used. In addition, these polymer materials include polymer materials such as perylene dyes, coumarin dyes, rhodamine dyes, rubrene, perylene, 9,10-diphenylanthracene, tetraphenylbutadiene, Nile red, coumarin 6, and quinacridone. It can also be used by doping a low molecular weight material such as.

  The cathode 50 is formed so as to cover the light emitting layer 60. For example, Ca is formed to a thickness of about 20 nm, and Al is formed thereon to a thickness of about 200 nm to form an electrode having a laminated structure, and the Al is reflected. It also functions as a layer. Although illustration is omitted, actually, a sealing substrate is stuck on the cathode 50 via an adhesive layer.

Further, the circuit unit 11 is provided below the organic EL element 3 as described above. The circuit unit 11 is formed on the element substrate 2. That is, a base protective layer 281 mainly composed of SiO ₂ is formed on the surface of the element substrate 2 as a base, and a silicon layer 241 is formed thereon. A gate insulating layer 282 mainly composed of SiO ₂ and / or SiN is formed on the surface of the silicon layer 241.

In the silicon layer 241, a region overlapping with the gate electrode 242 with the gate insulating layer 282 interposed therebetween is a channel region 241a. The gate electrode 242 is a part of a scanning line (not shown). On the other hand, a first interlayer insulating layer 283 mainly composed of SiO ₂ is formed on the surface of the gate insulating layer 282 that covers the silicon layer 241 and on which the gate electrode 242 is formed.

  Further, in the silicon layer 241, a low concentration source region 241b and a high concentration source region 241S are provided on the source side of the channel region 241a, while a low concentration drain region 241c and a high concentration drain are provided on the drain side of the channel region 241a. The region 241D is provided to form a so-called LDD (Light Doped Drain) structure. Among these, the high-concentration source region 241S is connected to the source electrode 243 through a contact hole 243a that opens over the gate insulating layer 282 and the first interlayer insulating layer 283. The source electrode 243 is configured as a part of a power supply line (not shown). On the other hand, the high-concentration drain region 241D is connected to the drain electrode 244 made of the same layer as the source electrode 243 through a contact hole 244a that opens through the gate insulating layer 282 and the first interlayer insulating layer 283.

  On the first interlayer insulating layer 283 on which the source electrode 243 and the drain electrode 244 are formed, for example, a planarizing film 284 mainly composed of an acrylic resin component is formed. The planarizing film 284 is formed of a heat-resistant insulating resin such as acrylic or polyimide, and has surface irregularities caused by the driving TFT 123 (driving element 4), the source electrode 243, the drain electrode 244, and the like. It is a well-known thing formed in order to eliminate.

  A pixel electrode 23 made of ITO or the like is formed on the surface of the planarizing film 284 and connected to the drain electrode 244 through a contact hole 23a provided in the planarizing film 284. That is, the pixel electrode 23 is connected to the high concentration drain region 241D of the silicon layer 241 through the drain electrode 244.

  On the surface of the planarization film 284 on which the pixel electrode 23 is formed, the pixel electrode 23 and the above-described inorganic partition wall 25 are formed, and on the inorganic partition wall 25, an organic partition wall 221 is formed. On the pixel electrode 23, the hole transport layer 70 and the light emitting layer 60 are formed inside the opening 25 a formed in the inorganic partition wall 25 and the opening 221 a formed in the organic partition wall 221, that is, in the pixel region. Are stacked in this order from the pixel electrode 23 side, thereby forming a functional layer.

(Usage of line head module)
Next, the usage pattern of the line head module of this embodiment will be described.
The line head module of this embodiment is used as an exposure device in an image forming apparatus. In this case, the line head module is disposed so as to face the photosensitive drum, and the light from the line head is imaged on the photosensitive drum by the SL array and used at an equal magnification.

(Tandem image forming device)
First, a tandem image forming apparatus will be described.
FIG. 8 is a schematic configuration diagram of a tandem image forming apparatus, and reference numeral 80 in FIG. 8 denotes the image forming apparatus. This image forming apparatus 80 includes the line head modules 101K, 101C, 101M, and 101Y of the previous embodiment that correspond to four corresponding photosensitive drums (image carriers) 41K, 41C, 41M, and 41Y. These are respectively arranged in the exposure apparatus, and are configured as a tandem system.

  The image forming apparatus 80 includes a driving roller 91, a driven roller 92, and a tension roller 93, and an intermediate transfer belt 90 is stretched around each of the rollers so as to be circulated in the direction of the arrow (counterclockwise) in FIG. Is. Photosensitive drums 41K, 41C, 41M, and 41Y are arranged at predetermined intervals with respect to the intermediate transfer belt 90. These photosensitive drums 41K, 41C, 41M, and 41Y have a photosensitive layer as an image carrier on the outer peripheral surface thereof.

Here, K, C, M, and Y in the symbols mean black, cyan, magenta, and yellow, respectively, and indicate that the photoconductors are for black, cyan, magenta, and yellow, respectively.
The meanings of these symbols (K, C, M, Y) are the same for the other members. The photosensitive drums 41K, 41C, 41M, and 41Y are driven to rotate in the arrow direction (clockwise) in FIG. 8 in synchronization with the driving of the intermediate transfer belt 90.

  Around each photosensitive drum 41 (K, C, M, Y), charging means (corona charger) 42 for uniformly charging the outer peripheral surface of the photosensitive drum 41 (K, C, M, Y), respectively. (K, C, M, Y) and rotation of the photosensitive drum 41 (K, C, M, Y) on the outer peripheral surface uniformly charged by the charging means 42 (K, C, M, Y) The line head module 101 (K, C, M, Y) of the present invention that sequentially scans the line in synchronism with each other is provided.

  Further, a developing device 44 (K, C) that applies a toner as a developer to the electrostatic latent image formed by the line head module 101 (K, C, M, Y) to form a visible image (toner image). , M, Y) and a primary transfer roller 45 (K) as transfer means for sequentially transferring the toner image developed by the developing device 44 (K, C, M, Y) to the intermediate transfer belt 90 which is a primary transfer target. , C, M, Y) and a cleaning device 46 (K, C, M) as a cleaning means for removing toner remaining on the surface of the photosensitive drum 41 (K, C, M, Y) after being transferred. , Y).

  Here, each line head module 101 (K, C, M, Y) is installed such that the arrangement direction of the organic EL elements is along the bus line of the photosensitive drum 41 (K, C, M, Y). The emission energy peak wavelength of each line head module 101 (K, C, M, Y) and the sensitivity peak wavelength of the photosensitive drum 41 (K, C, M, Y) are set so as to substantially match. Yes.

  The developing device 44 (K, C, M, Y) uses, for example, a non-magnetic one-component toner as a developer. The film thickness of the developed developer is regulated by a regulating blade, and the developing roller is brought into contact with or pressed against the photosensitive drum 41 (K, C, M, Y), whereby the photosensitive drum 41 (K, C, M, A developer is attached in accordance with the potential level of Y) and developed as a toner image.

  The black, cyan, magenta, and yellow toner images formed by the four-color single-color toner image forming station are intermediated by the primary transfer bias applied to the primary transfer roller 45 (K, C, M, Y). Primary transfer is sequentially performed on the transfer belt 90. The toner images that are sequentially superimposed on the intermediate transfer belt 90 to become a full color are secondarily transferred to the recording medium P such as paper by the secondary transfer roller 66 and further pass through the fixing roller pair 61 that is a fixing unit. Then, the toner image is fixed on the recording medium P and then discharged onto a paper discharge tray 68 formed on the upper part of the apparatus by a pair of paper discharge rollers 62.

  In FIG. 8, reference numeral 63 is a paper feed cassette in which a large number of recording media P are stacked and held, 64 is a pickup roller for feeding the recording media P from the paper feed cassette 63 one by one, and 65 is a secondary transfer. A pair of gate rollers for defining the supply timing of the recording medium P to the secondary transfer portion of the roller 66; a secondary transfer roller 66 as a secondary transfer means for forming a secondary transfer portion with the intermediate transfer belt 90; A cleaning blade 67 serves as a cleaning unit that removes toner remaining on the surface of the intermediate transfer belt 90 after the secondary transfer.

(4-cycle image forming apparatus)
Next, a four-cycle image forming apparatus will be described.
FIG. 9 is a schematic configuration diagram of a 4-cycle image forming apparatus image. In FIG. 9, the image forming apparatus 160 includes, as main components, a developing device 161 having a rotary configuration, a photosensitive drum 165 that functions as an image carrier, and the line of the previous embodiment that functions as an image writing unit (exposure unit). A head module 167, an intermediate transfer belt 169, a paper conveyance path 174, a fixing unit heating roller 172, and a paper feed tray 178 are provided.

  The developing device 161 is configured such that the developing rotary 161a rotates in the direction of arrow A about the shaft 161b. The inside of the development rotary 161a is divided into four, and image forming units for four colors of yellow (Y), cyan (C), magenta (M), and black (K) are provided. Reference numerals 162a to 162d are arranged in the image forming units for the four colors. The developing rollers rotate in the direction of the arrow B, and the toner supply rollers 163a to 163d rotate in the direction of the arrow C. Reference numerals 164a to 164d are regulating blades that regulate the toner to a predetermined thickness.

  In FIG. 9, reference numeral 165 denotes a photosensitive drum that functions as an image carrier as described above, 166 a primary transfer member, and 168 a charger. Reference numeral 167 denotes a line head module according to the present embodiment that functions as an image writing unit (exposure unit). The photosensitive drum 165 is rotationally driven in the direction of arrow D, which is the direction opposite to the developing roller 162a, by a drive motor (not shown), for example, a step motor.

  The intermediate transfer belt 169 is stretched between the driving roller 170a and the driven roller 170b. The driving roller 170 a is connected to the driving motor of the photosensitive drum 165 and transmits power to the intermediate transfer belt 169. That is, the drive roller 170a of the intermediate transfer belt 169 is rotated in the direction of arrow E which is the opposite direction to the photosensitive drum 165 by the drive motor.

  The paper transport path 174 is provided with a plurality of transport rollers, a pair of paper discharge rollers 176, and the like, so that the paper is transported. An image (toner image) on one side carried on the intermediate transfer belt 169 is transferred to one side of the paper at the position of the secondary transfer roller 171. The secondary transfer roller 171 is brought into contact with and separated from the intermediate transfer belt 169 by a clutch. When the clutch is turned on, the secondary transfer roller 171 is brought into contact with the intermediate transfer belt 169 so that an image is transferred onto a sheet.

The sheet on which the image has been transferred as described above is then subjected to a fixing process by a fixing device having a fixing heater H. The fixing device is provided with a heating roller 172 and a pressure roller 173.
The sheet after the fixing process is drawn into the discharge roller pair 176 and proceeds in the direction of arrow F. When the paper discharge roller pair 176 rotates in the reverse direction from this state, the paper reverses its direction and advances in the double-sided printing conveyance path 175 in the direction of arrow G. 177 is an electrical component box, 178 is a paper feed tray for storing paper, and 179 is a pickup roller provided at the outlet of the paper feed tray 178.

  For example, a low-speed brushless motor is used as a drive motor for driving the transport roller in the paper transport path. For the intermediate transfer belt 169, a step motor is used because color misregistration correction is required. Each of these motors is controlled by a signal from a control means (not shown).

  In the state shown in FIG. 9, a yellow (Y) electrostatic latent image is formed on the photosensitive drum 165, and a high voltage is applied to the developing roller 162a, whereby a yellow image is formed on the photosensitive drum 165. Is done. When the yellow back side and front side images are all carried on the intermediate transfer belt 169, the development rotary 161a rotates 90 degrees in the direction of arrow A.

  The intermediate transfer belt 169 rotates once and returns to the position of the photosensitive drum 165. Next, two images of cyan (C) are formed on the photosensitive drum 165, and this image is carried on the yellow image carried on the intermediate transfer belt 169. Thereafter, the 90-degree rotation of the development rotary 161 and the one-rotation process after the image is carried on the intermediate transfer belt 169 are repeated in the same manner.

For carrying four color images, the intermediate transfer belt 169 rotates four times, and then the rotation position is further controlled to transfer the image onto the sheet at the position of the secondary transfer roller 171. The sheet fed from the sheet feed tray 178 is conveyed by the conveyance path 174, and the color image is transferred to one side of the sheet at the position of the secondary transfer roller 171. The sheet on which the image is transferred on one side is reversed by the discharge roller pair 176 as described above, and stands by on the conveyance path. Thereafter, the sheet is conveyed to the position of the secondary transfer roller 171 at an appropriate timing, and the color image is transferred to the other side. The housing 180 is provided with an exhaust fan 181.
The image forming apparatus including the line head module of the present invention is not limited to the above, and various modifications can be made.

The perspective view which shows the side cross-section structure of a line head module. The plane block diagram of a line head. The perspective block diagram of SL array. The figure which shows the relationship between arrangement | positioning of a line head and SL array, and light quantity distribution. The figure which shows the relationship between arrangement | positioning of a line head and SL array, and light quantity distribution. Explanatory drawing of the brightness correction method which concerns on embodiment. The figure which shows the detailed structure of a line head. 1 is a diagram illustrating an example of an image forming apparatus. FIG. 4 is a diagram illustrating another example of an image forming apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Line head, 2 ... Element board | substrate (board | substrate), 3 ... Organic EL element (light emitting element), 3A ... Light emitting element row | line | column, 4 ... Drive element, 31 ... SL array (lens array), 31a ... SL element (lens element) ), 52... Head case, 60... Light emitting layer, 70... Hole transport layer, 80 and 160.

Claims (5)

A luminance correction method for a light emitting device in which a plurality of light emitting elements are arranged in a plane,
Turning on the light emitting element and measuring the light quantity distribution of the output light;
Based on the obtained light quantity distribution, a step of determining aging brightness that is light emission brightness at the time of aging of each light emitting element;
Illuminating each of the light emitting elements with the aging luminance to perform aging.   2. The luminance correction method for a light emitting device according to claim 1, wherein the aging luminance is set to a higher luminance as the light emitting element has a larger light amount in the light amount distribution.   The brightness correction method for a light-emitting device according to claim 1, wherein the aging brightness is made larger than the light-emission brightness during normal operation of the light-emitting element. The present invention can be applied to a line head module including a line head including a plurality of light emitting elements arranged in a plane and a lens array that forms an image of light output from the line head on an exposed portion via a lens element. A line head luminance correction method,
Illuminating the light emitting element and measuring a light amount distribution of light output through the lens array;
Based on the obtained light quantity distribution, a step of determining aging brightness that is light emission brightness at the time of aging of each light emitting element;
Illuminating each of the light emitting elements at the aging luminance to perform aging.   The line head luminance correction method according to claim 4, wherein the aging luminance is set to a higher luminance as the light emitting element is located at a larger light amount in the light amount distribution.

Images