JP2008080643A - Exposure apparatus, image forming apparatus, and operation method of exposure apparatus - Google Patents

Abstract

An exposure apparatus capable of stable exposure is provided.
A plurality of transparent data electrodes are formed on a substrate. These data electrodes 30 are transparent electrodes made of ITO (tin-doped indium oxide). These data electrodes 30 are arranged in order in a direction parallel to the axis of the photosensitive drum 2. A plurality of selection electrodes 40 are provided on the insulating film 60, and these selection electrodes 40 extend in a direction parallel to the axis of the photosensitive drum 2. An opening 61 is formed in the insulating film 60 at each intersection of the data electrode 30 and the selection electrode 40 in plan view. An EL layer 50 is embedded in each opening 61, and the EL layer 50 is sandwiched between the data electrode 30 and the selection electrode 40. An image is formed on one sheet of paper 99 when any one of these selection electrodes 40 is designated, and another selection electrode 40 is designated when an image is formed on the next sheet 99.
[Selection] Figure 2

Description

  The present invention relates to an image forming apparatus that forms an image on a recording medium, an exposure apparatus that exposes a photoreceptor of the image forming apparatus, and an operation method of the exposure apparatus.

  The page printer forms an electrostatic latent image on the peripheral surface of the photosensitive drum by exposing it along the generating line of the rotating photosensitive drum, and exposes the electrostatic latent image by attaching toner to the photosensitive drum. The image of the photosensitive drum is transferred to paper.

  A general exposure apparatus forms a latent image on a photosensitive drum by scanning a laser beam dot-sequentially along a line with a rotating polygon lens. An exposure apparatus in which organic EL (Electroluminescent) elements are arranged in a line is also considered. Organic EL elements have problems with respect to lifetime, light emission intensity, and exposure time compared to other light emitting elements such as LEDs. That is, if the light emission intensity of the organic EL element is increased, the exposure time can be shortened and an image can be formed at a high speed, but there is a problem that the life of the organic EL element is shortened, while the light emission intensity of the organic EL element is weakened. Then, the life of the organic EL element is extended, but the exposure time is lengthened and the time required for image formation is extended.

In view of this, there has been proposed an exposure apparatus in which organic EL elements are arranged in a plurality of columns and multiple exposure is performed with the plurality of organic EL elements to form pixels for one dot (see Patent Document 1 and Patent Document 2). That is, an image of one line is exposed to paper with a certain row of organic EL elements, and one line is again returned with the next row of organic EL elements at the timing when the paper is moved and the line reaches the next row. These images are overlaid on a sheet of paper, so that one dot of pixels is formed by multiple exposure.
JP 2003-341140 A JP 2003-341141 A

  However, the timing at which one line of paper reaches the organic EL element in the next row from the organic EL element in the certain row must be synchronized with the timing at which the organic EL element in the next row emits light. It is difficult. In particular, a complicated circuit such as a shift register for transferring light emission data from one column to the next column must be mounted on the exposure apparatus. Therefore, there is a problem that the structure of the exposure apparatus is complicated and the exposure apparatus is expensive.

  Accordingly, the present invention has been made to solve the above-described problems, and an object thereof is to provide an exposure apparatus that is inexpensive and has a simple structure.

In order to solve the above problems, the invention according to claim 1
In an exposure apparatus that is provided in an image forming apparatus that forms an image on a recording medium and that exposes a photoreceptor,
A plurality of data electrodes provided for each of a plurality of rows parallel to the moving direction of the photosensitive member;
A plurality of selection electrodes provided for each of a plurality of rows;
An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of the data electrode and the selection electrode,
During the image formation on the recording medium, any one of the plurality of selection electrodes is designated, and the other row of selection electrodes is not designated, and the EL of the row connected to the designated selection electrode The image formation of one recording medium is performed only by the elements, and the designation of the selection electrode is switched to the selection electrode of another column every time the image formation is completed.

The invention according to claim 2
In an exposure apparatus that is provided in an image forming apparatus that forms an image on a recording medium and that exposes a photoreceptor,
A plurality of data electrodes provided for each of a plurality of rows parallel to the moving direction of the photosensitive member;
A plurality of selection electrodes provided for each of a plurality of rows;
An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of the data electrode and the selection electrode,
One of the plurality of selection electrodes is designated during image formation on the recording medium, and the image formation on the plurality of recording media is performed only by the EL elements in the row connected to the designated selection electrode. Each time the image formation on the recording medium is completed, the designation of the selection electrode is switched to the selection electrode in another column.

The invention according to claim 3
In an exposure apparatus that is provided in an image forming apparatus that forms an image on a recording medium and that exposes a photoreceptor,
A plurality of data electrodes provided for each of a plurality of rows parallel to the moving direction of the photosensitive member;
A plurality of selection electrodes provided for each of a plurality of rows;
An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of the data electrode and the selection electrode,
During the image formation on the recording medium, any one of the plurality of selection electrodes is designated, and the other row of selection electrodes is not designated, and the EL of the row connected to the designated selection electrode Image formation of the recording medium is performed only by the element,
Each time the formation of an image on a predetermined number of recording media is completed within a predetermined period, the selection of the selection electrode is switched to the selection electrode in another column.

The invention according to claim 4
In an exposure apparatus that is provided in an image forming apparatus that forms an image on a recording medium and that exposes a photoreceptor,
A plurality of data electrodes provided for each of a plurality of rows parallel to the moving direction of the photosensitive member;
A plurality of selection electrodes provided for each of a plurality of rows;
An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of the data electrode and the selection electrode,
During the image formation on the recording medium, any one of the plurality of selection electrodes is designated, and the other row of selection electrodes is not designated, and the EL of the row connected to the designated selection electrode Image formation of the recording medium is performed only by the element,
When the EL element corresponding to the designated selection electrode reaches a predetermined temperature, the designation of the selection electrode is switched to the selection electrode in another column.

The invention according to claim 5 is the exposure apparatus according to claim 4,
When the EL element overlapped with the designated selection electrode reaches the predetermined temperature during the image formation of the recording medium, the designation of the selection electrode is changed to the selection electrode of another row after the image formation of the recording medium is completed. It can be switched.

The invention according to claim 6
In an exposure apparatus that is provided in an image forming apparatus that forms an image on a recording medium and that exposes a photoreceptor,
A plurality of data electrodes provided for each of a plurality of rows parallel to the moving direction of the photosensitive member;
A plurality of selection electrodes provided for each of a plurality of rows;
An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of the data electrode and the selection electrode,
During the image formation on the recording medium, any one of the plurality of selection electrodes is designated, and the other row of selection electrodes is not designated, and the EL of the row connected to the designated selection electrode Image formation of the recording medium is performed only by the element,
When the applied current flowing through the EL element decreases to a predetermined value due to deterioration of the EL element over time, the designation of the selection electrode is switched to the selection electrode in another column.

The invention according to claim 7 is the exposure apparatus according to claim 6,
When the timing at which the applied current applied to the plurality of data electrodes decreases to a predetermined value is during the image formation of the recording medium, the selection of the other electrode is selected as the selection electrode after the image formation of the recording medium is completed. It can be switched to an electrode.

The invention according to claim 8 provides:
In an exposure apparatus that is provided in an image forming apparatus that forms an image on a recording medium and that exposes a photoreceptor,
A plurality of data electrodes provided for each of a plurality of rows parallel to the moving direction of the photosensitive member;
A plurality of selection electrodes provided for each of a plurality of rows;
An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of the data electrode and the selection electrode,
During the image formation on the recording medium, any one of the plurality of selection electrodes is designated, and the other row of selection electrodes is not designated, and the EL of the row connected to the designated selection electrode Image formation of the recording medium is performed only by the element,
When the applied voltage applied to the EL element increases to a predetermined value due to deterioration of the EL element over time, the designation of the selection electrode is switched to the selection electrode in another column.

The invention according to claim 9 is the exposure apparatus according to claim 8,
When the timing at which the applied voltage applied to the plurality of data electrodes increases to a predetermined value is during the image formation of the recording medium, the selection of the other electrode is the designation of the selection electrode after the image formation of the recording medium is completed. It can be switched to an electrode.

The invention according to claim 10 is:
In an exposure apparatus that is provided in an image forming apparatus that forms an image on a recording medium and that exposes a photoreceptor,
A plurality of data electrodes provided for each of a plurality of rows parallel to the moving direction of the photosensitive member;
A plurality of selection electrodes provided for each of a plurality of rows;
An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of the data electrode and the selection electrode,
During the image formation on the recording medium, any one of the plurality of selection electrodes is designated, and the other row of selection electrodes is not designated, and the EL of the row connected to the designated selection electrode Image formation of the recording medium is performed only by the element,
Each time the image forming apparatus is activated, the designation of the selection electrode is switched to the selection electrode in another column.

The invention according to claim 11 is the exposure apparatus according to any one of claims 1 to 10,
The data electrode is connected to a lighting drive circuit including a plurality of transistors.

The invention according to claim 12 is the image forming apparatus,
A photoreceptor,
An exposure apparatus according to any one of claims 1 to 11 is provided.

The invention according to claim 13 is:
In an operation method of an exposure apparatus provided in an image forming apparatus for forming an image on a recording medium and exposing a photosensitive member,
The exposure apparatus includes a plurality of data electrodes provided for each of a plurality of columns parallel to a direction in which the photosensitive member moves, a plurality of selection electrodes provided for each of a plurality of rows, the data electrodes, and the selection electrodes. An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of
During the image formation on the recording medium, any one of the plurality of selection electrodes is designated, and the other row of selection electrodes is not designated, and the EL of the row connected to the designated selection electrode Image formation of the recording medium is performed only by the element,
Each time the image formation on one recording medium is completed, the designation of the selection electrode is switched to the selection electrode in another column.

The invention according to claim 14 is:
In an operation method of an exposure apparatus provided in an image forming apparatus for forming an image on a recording medium and exposing a photosensitive member,
The exposure apparatus includes a plurality of data electrodes provided for each of a plurality of columns parallel to a direction in which the photosensitive member moves, a plurality of selection electrodes provided for each of a plurality of rows, the data electrodes, and the selection electrodes. An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of
During the image formation on the recording medium, any one of the plurality of selection electrodes is designated, and the other row of selection electrodes is not designated, and the EL of the row connected to the designated selection electrode Image formation of the recording medium is performed only by the element,
Each time the image formation on a plurality of recording media is completed, the selection of the selection electrode is switched to the selection electrode in another column.

The invention according to claim 15 is:
In an operation method of an exposure apparatus provided in an image forming apparatus for forming an image on a recording medium and exposing a photosensitive member,
The exposure apparatus includes a plurality of data electrodes provided for each of a plurality of columns parallel to a direction in which the photosensitive member moves, a plurality of selection electrodes provided for each of a plurality of rows, the data electrodes, and the selection electrodes. An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of
During the image formation on the recording medium, any one of the plurality of selection electrodes is designated, and the other row of selection electrodes is not designated, and the EL of the row connected to the designated selection electrode Image formation of the recording medium is performed only by the element,
Each time the formation of an image on a predetermined number of recording media is completed within a predetermined period, the selection of the selection electrode is switched to the selection electrode in another column.

The invention according to claim 16 provides:
In an operation method of an exposure apparatus provided in an image forming apparatus for forming an image on a recording medium and exposing a photosensitive member,
The exposure apparatus includes a plurality of data electrodes provided for each of a plurality of columns parallel to a direction in which the photosensitive member moves, a plurality of selection electrodes provided for each of a plurality of rows, the data electrodes, and the selection electrodes. An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of
During the image formation on the recording medium, any one of the plurality of selection electrodes is designated, and the other row of selection electrodes is not designated, and the EL of the row connected to the designated selection electrode Image formation of the recording medium is performed only by the element,
When the electroluminescent layer overlapping the designated selection electrode reaches a predetermined temperature, the designation of the selection electrode is switched to the selection electrode in another column.

The invention according to claim 17 provides:
In an operation method of an exposure apparatus provided in an image forming apparatus for forming an image on a recording medium and exposing a photosensitive member,
The exposure apparatus includes a plurality of data electrodes provided for each of a plurality of columns parallel to a direction in which the photosensitive member moves, a plurality of selection electrodes provided for each of a plurality of rows, the data electrodes, and the selection electrodes. An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of
During the image formation on the recording medium, any one of the plurality of selection electrodes is designated, and the other row of selection electrodes is not designated, and the EL of the row connected to the designated selection electrode Image formation of the recording medium is performed only by the element,
When the applied current flowing through the EL element decreases to a predetermined value due to deterioration of the EL element over time, the designated selection electrode is switched to the selection electrode of another column.

The invention according to claim 18
In an operation method of an exposure apparatus provided in an image forming apparatus for forming an image on a recording medium and exposing a photosensitive member,
The exposure apparatus includes a plurality of data electrodes provided for each of a plurality of columns parallel to a direction in which the photosensitive member moves, a plurality of selection electrodes provided for each of a plurality of rows, the data electrodes, and the selection electrodes. An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of
During the image formation on the recording medium, any one of the plurality of selection electrodes is designated, and the other row of selection electrodes is not designated, and the EL of the row connected to the designated selection electrode Image formation of the recording medium is performed only by the element,
When the applied voltage applied to the EL element increases to a predetermined value due to deterioration of the EL element over time, the designation of the selection electrode is switched to the selection electrode in another column.

The invention according to claim 19 is
In an operation method of an exposure apparatus provided in an image forming apparatus for forming an image on a recording medium and exposing a photosensitive member,
The exposure apparatus includes a plurality of data electrodes provided for each of a plurality of columns parallel to a direction in which the photosensitive member moves, a plurality of selection electrodes provided for each of a plurality of rows, the data electrodes, and the selection electrodes. An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of
During the image formation on the recording medium, any one of the plurality of selection electrodes is designated, and the other row of selection electrodes is not designated, and the EL of the row connected to the designated selection electrode Image formation of the recording medium is performed only by the element,
Each time the image forming apparatus is activated, the designation of the selection electrode is switched to the selection electrode in another column.

According to the present invention, during the image formation on the recording medium, any one of the plurality of selection electrodes is designated, and the other row of selection electrodes is not designated. Since the image formation on the recording medium is performed only by the EL elements of the connected columns, the EL elements of the columns connected to the non-designated selection electrodes do not emit light, so there is no deterioration due to light emission.
Since the designation of the selection electrode is switched to the selection electrode in another column at a predetermined timing, a decrease in the light emission luminance of the EL element can be suppressed, and exposure can be performed for a long time.
Even if a defective EL element is generated, it is possible to perform exposure by designating a selection electrode in another column without designating a selection electrode connected to the defective EL element. Lead to improvement

  The best mode for carrying out the present invention will be described below with reference to the drawings. However, although various technically preferable limitations for implementing the present invention are given to the embodiments described below, the scope of the invention is not limited to the following embodiments and illustrated examples. Moreover, in the following description, the term electroluminescent is abbreviated as EL.

[First embodiment]
FIG. 1 shows a schematic diagram of the image forming apparatus 1.
The image forming apparatus 1 includes a photosensitive drum 2, a charging roller 3, an imaging optical system 4, a developing device 5, a developing roller 6, a transfer roller 7, fixing rollers 8 and 9, a cleaner 10, An eraser light source 11, a conveyor belt 12, an LSI chip 13, and an exposure panel 20 are provided.

  The conveyance belt 12 is sandwiched between the photosensitive drum 2 and the transfer roller 7, and is sandwiched between the fixing roller 8 and the fixing roller 9. When the transport belt 12 moves in the direction of arrow Z, the paper 99 placed on the transport belt 12 is transported in the direction of arrow Z. The paper 99 is a recording medium on which an image is formed by the image forming apparatus 1.

  Since the optical semiconductor layer is formed on the peripheral surface of the photosensitive drum 2, charges are stored on the peripheral surface of the photosensitive drum 2, and when the peripheral surface of the photosensitive drum 2 is irradiated with light, the charges are removed. . The charging roller 3 charges the peripheral surface of the photosensitive drum 2. Although details of the exposure panel 20 will be described later, a linear image parallel to the axial direction of the photosensitive drum 2 appears on the exposure panel 20 when the exposure panel 20 emits light. The imaging optical system 4 includes rod lenses (green lenses) arranged in an array along the generatrices of the photosensitive drum 2, and the image of the exposure panel 20 is connected to the photosensitive drum 2 at an erecting equal magnification. It is something to image. Further, the LSI chip 13 is connected to the film substrate on the exposure panel 20, and the exposure panel 20 and the imaging optical system 4 are mounted on the housing 14, and these are unitized.

  When the photosensitive drum 2 is exposed along the generatrix by the exposure panel 20 and the imaging optical system 4, the charge accumulated on the peripheral surface of the charged photosensitive drum 2 is partially removed. An electrostatic latent image is formed along the generatrix of the photosensitive drum 2. The developing device 5 stores colored fine particles called charged toner. The developing roller 6 develops the electrostatic latent image formed on the photosensitive drum 2 after exposure. That is, the toner adheres to the developing roller 6 in the developing device 5, and the toner attached to the developing roller 6 adheres to the photosensitive drum 2. Here, the charged portion of the photosensitive drum 2 (that is, the portion that has not been irradiated with light) does not adhere to the toner due to repulsion, and the portion of the photosensitive drum 2 that has been neutralized (that is, the portion that has been irradiated with light). ), And the electrostatic latent image on the photosensitive drum 2 becomes apparent. The transfer roller 7 is in pressure contact with the photosensitive drum 2, and the developed image is transferred to the peripheral surface of the photosensitive drum 2 onto a sheet 99 sandwiched between the photosensitive drum 2 and the transfer roller 7. That is, the paper 99 transported in the direction of the arrow Z is pressed against the photosensitive drum 2 by the transfer roller 7, and further charged by the transfer roller 7 so as to attract the toner, whereby the photosensitive drum 2 is charged. The adhered toner adheres to the paper 99. The cleaner 10 removes the toner remaining on the photosensitive drum 2 after the transfer. The fixing rollers 8 and 9 fix the toner adhering to the paper 99 to the paper 99 by sandwiching the paper 99 after the transfer and heating the paper 99. The eraser light source 11 removes the charge of the entire bus of the photosensitive drum 2 by irradiating light along the bus of the rotating photosensitive drum 2 after the toner removal.

The exposure panel 20 will be described in detail with reference to FIGS. FIG. 2 is a plan view of the exposure panel 20, and FIG. 3 is a cross-sectional view taken along the line III-III in FIG.
The substrate 21 is made of a transparent material. The substrate 21 is, for example, a transparent glass substrate or a transparent resin substrate. One surface 22 of the substrate 21 is an exit surface, the surface 22 is orthogonal to the optical axis of the imaging optical system 4, and the surface 22 becomes an object surface by the imaging optical system 4. The generatrix becomes an imaging plane by the imaging optical system 4.

  A plurality of data electrodes 30 are formed on the other surface 23 of the substrate 21. These data electrodes 30 are transparent electrodes made of ITO (tin-doped indium oxide) or the like. The data electrodes 30 are provided in a strip shape so as to extend in the row direction which is the direction X in which the photosensitive drum 2 moves (the direction orthogonal to the axis of the photosensitive drum 2). They are arranged side by side so as to be spaced apart at equal intervals in the direction parallel to the axis, that is, in the column direction. These data electrodes 30 are electrodes that serve as anodes in each pixel. The number of data electrodes 30 is 7000 to 15000.

  On the substrate 21, an insulating film 60 in which a plurality of (in the figure, three) openings 61 are provided on each data electrode 30 is coated. Each data electrode 30 has a terminal 31 of the data electrode 30 exposed from the insulating film 60 on one side along the column direction of the substrate 21.

  A plurality of selection electrodes 40 are provided on the insulating film 60 so as to straddle a plurality of openings 61 along the column direction, respectively, and these selection electrodes 40 extend in a direction perpendicular to the axis of the photosensitive drum 2. is doing. In this way, three selection electrodes 40 are arranged at equal intervals along the extending direction (row direction) of the data electrodes 30. These selection electrodes 40 are orthogonal to the data electrodes 30 in plan view, that is, when viewed in the axial direction of the imaging optical system 4. A portion where the selection electrode 40 and the data electrode 30 intersect with each other is an organic EL element 52 which will be described later. The organic EL elements 52 are arranged in a matrix of 3 columns × 7000 to 15000 rows on the exposure panel 20. become.

Each selection electrode 40 includes a portion extending in the column direction on the insulating film 60 and a portion extending in the row direction at one end of the column direction portion, and extending in the row direction. The plurality of contact holes 42 provided in the insulating film 60 are buried at the ends of the contacts.
A plurality of lead wires 41 obtained by patterning the same transparent conductive film as the data electrodes 30 are provided on the substrate 21 in the same number as the selection electrodes 40. Each lead wire 41 is arranged at a position corresponding to a plurality of contact holes 42 provided at one end in the insulating film 60, and the other end is exposed from the insulating film 60 similarly to the terminal 31 of the data electrode 30 and the substrate 21. It is provided so as to be arranged on one side along the column direction. For this reason, each selection electrode 40 is connected to a corresponding lead wire 41 through a plurality of contact holes 42.

  The selection electrode 40 is made of a material having a work function lower than that of the data electrode 30, and is made of, for example, a simple substance or an alloy containing at least one of magnesium, calcium, lithium, barium, and a rare earth metal. The selection electrode 40 may have a laminated structure in which layers of the above various materials are laminated, or a laminated structure in which a metal layer having a higher work function is deposited in addition to the above layers of various materials. May be. As a specific example of the laminated structure, the lower layer side of the selection electrode 40 is a high-purity barium layer or lithium layer having a low work function, and the upper layer side of the selection electrode 40 is a high work function aluminum covering the barium layer or lithium layer. It is a layer containing an aluminum alloy. These selection electrodes 40 are electrodes that serve as cathodes in each pixel. In the drawing, the number of selection electrodes 40 is three, but may be two, or four or more.

  An opening 61 of the insulating film 60 is formed in the insulating film 60 at each intersection between the data electrode 30 and the selection electrode 40 in plan view. The electroluminescence layer 50 is embedded in each opening 61, and the electroluminescence layer 50 is sandwiched between the data electrode 30 and the selection electrode 40 to form the organic EL element 52.

  The electroluminescent layer (hereinafter referred to as EL layer) 50 contains a light emitting material (phosphor) that is an organic compound, but the light emitting material may be a high molecular weight material or a low molecular weight material. There may be. The layer 50 may be a single layer or a stacked structure of a plurality of layers. When the EL layer 50 has a laminated structure, there is no particular limitation, but the EL layer 50 may have a three-layer structure that becomes a hole transport layer, a light emitting layer, and an electron transport layer in order from the bottom. A two-layer structure serving as a layer and a light-emitting layer may be used, or a structure in which an electron or hole injection layer is interposed between appropriate layers in these layer structures may be used.

  The EL layer 50 is a layer that emits light when the data electrode 30 in the lower layer becomes higher in potential than the selection electrode 40 in the upper layer and electrons and holes are respectively transported therein. The intensity correlates with the flowing current.

  A residual layer 51 is formed on the insulating film 60 and around the opening 61. The residual layer 51 is not sandwiched between the data electrode 30 and the selection electrode 40 or does not emit light because the insulating film 60 is interposed therebetween, but has the same components as the EL layer 50. At the same time that the residual layer 51 is formed by coating on the insulating film 60 in which the openings 61 are formed, the EL layers 50 are buried in the openings 61, and the EL layers 50 are patterned in a matrix. The residual layer 51 may be continuous or discontinuous with the EL layer 50. In the case of patterning each EL layer 50 by discharging an organic compound-containing liquid (a solution obtained by dissolving the raw material of the EL layer 50 in a solvent) into each opening 61 by an inkjet method (droplet discharge method). The residual layer 51 is not formed.

  The residual layer 51 and the plurality of selection electrodes 40 are covered with a sealing material 70 containing at least one of water, an inorganic material that seals oxygen, and an organic material, and the sealing plate 80 covers the sealing material 70 from above. ing.

  Although the surface 22 of the substrate 21 faces the incident part of the imaging optical system 4, the surface 81 of the opposite sealing plate 80 may face the incident part of the imaging optical system 4. In this case, the selection electrode 40, the sealing material 70, and the sealing plate 80 are transparent, and the surface 81 of the sealing plate 80 becomes the emission surface. The selection electrode 40 can be made transparent as a whole by coating the above-described low work function material as thin as about 1 to 10 nm and then depositing a transparent conductive film such as ITO thereon by 50 nm or more. At this time, the data electrode 30 preferably includes a reflective conductive film, and may have a structure in which a transparent conductive film such as ITO is coated on a layer including light reflective aluminum or an aluminum alloy.

  Further, although the data electrode 30 is an anode and the selection electrode 40 is a cathode, the data electrode 30 may be a cathode and the selection electrode 40 may be an anode.

  As described above, the exposure panel 20 has a simple structure including a plurality of data electrodes 30, a plurality of selection electrodes 40, a plurality of EL layers 50, and the like, and complicated circuits and the like are not patterned on the exposure panel 20. Therefore, it is possible to provide an exposure panel 20 that is inexpensive and does not require manufacturing costs.

Next, a method for manufacturing the exposure panel 20 will be described.
A transparent conductive thin film (for example, ITO film) is formed on the surface 23 of the substrate 21, and the thin film is processed by photolithography and etching. Thereby, a plurality of data electrodes 30 and a plurality of lead wires 41 are formed. Thereafter, the resist is removed.

  Subsequently, the insulating film 60 is deposited using a CVD apparatus or the like while the mask is formed by photolithography, and the mask is removed. Subsequently, a plurality of contact holes 42 and a plurality of openings 61 are formed in the insulating film 60. Here, a plurality of openings 61 are formed on each data electrode 30 along each data electrode 30, and openings 61 corresponding to the number of selection electrodes 40 are arranged in a row for each data electrode 30, A plurality of openings 61 are arranged in a matrix. Therefore, the number of openings 61 is the product of the number of data electrodes 30 and the number of selection electrodes 40.

  Subsequently, an EL layer 50 made of a low molecular light emitting material is embedded in the opening 61 by covering the insulating film 60 with a metal mask and laminating a low molecular light emitting material in the opening of the metal mask. A residual layer 51 is deposited on the insulating film 60. Then, the metal mask is removed. In addition, by discharging the organic compound-containing liquid as droplets to each opening 61 by an ink jet method (droplet discharge method), the EL layer 50 is embedded in each opening 61 and the residual layer 51 is not formed. good.

  Subsequently, by performing a vapor deposition method using a metal mask (openings corresponding to the plurality of selection electrodes 40), an aluminum alloy or the like is formed after forming a low work function film such as magnesium, for example. The plurality of selection electrodes 40 formed by forming this film are patterned in a separated state, and then the metal mask is removed.

  Subsequently, sealing is performed on the selection electrode 40, the residual layer 51, and the insulating film 60 with a sealing material 70 and a sealing plate 80. Subsequently, the LSI chip 13 is connected to the substrate 21 from above the terminals 31 and the lead wires 41 by a film substrate (not shown), and the terminals of the LSI chip 13 and the terminals 31 and the lead wires 41 are connected. The LSI chip 13 may be bonded to the substrate 21 by COG (chip on glass).

  The above exposure panel 20 is mounted on the housing 14, and the imaging optical system 4 is also mounted on the housing 14, so that the imaging optical system 4 and the exposure panel 20 are opposed to each other.

Next, the LSI chip 13 will be described with reference to FIG.
The LSI chip 13 includes a drive control unit 15, and the drive control unit 15 includes a DAC 17 and a switching unit 16. The drive control unit 15 is connected to the main body control unit 18, and the drive control unit 15 is controlled by a signal from the main body control unit 18.

  The main body control unit 18 creates a gradation data signal for each pixel based on the print image data, and sequentially outputs the gradation data signal to the drive control unit 15. The main body control unit 18 outputs a control signal such as a clock signal to the drive control unit 15 in order to select one of the plurality of selection electrodes 40.

  The drive control unit 15 performs digital / analog conversion on the gradation data sequentially input by the DAC 17 and outputs a light emission signal corresponding to the gradation data to the data electrode 30 at a predetermined timing. Here, the gradation data may be represented by the magnitude of the current, or may be represented by the magnitude of the voltage. The output of the DAC 17 may be a constant current output or a constant voltage output.

  Further, the drive control unit 15 changes the voltages of the plurality of selection electrodes 40 by the switching unit 16 according to the control signal input from the main body control unit 18, and designates the designated selection electrode 40 (hereinafter, designated designation voltage 40 is designated and selected). This is referred to as an electrode 40. The other non-designated selection electrode 40 is referred to as a non-designated selection electrode 40). Here, the drive control unit 15 makes the designated selection electrode 40 different from the voltage applied to the other non-designated selection electrode 40 by applying a voltage applied to any one of the plurality of selection electrodes 40. Specify 40.

  Specifically, when the plurality of selection electrodes 40 are cathodes, a low-potential selection voltage S (for example, ground potential) is applied to one designated selection electrode 40 among the plurality of selection electrodes 40, and the designated selection electrode 40 is used. The non-selection voltage N that is relatively higher than the selection voltage S is applied to the other non-selection electrodes 40 and the non-selection selection electrodes 40 are not specified. Therefore, when a light emission signal is applied to each data electrode 30, a voltage exceeding the light emission threshold is applied to the EL layer 50 between the designated selection electrode 40 and light is emitted when a current flows. The voltage of the EL layer 50 sandwiched between the non-designated selection electrode 40 and each data electrode 30 does not emit light because it does not exceed the light emission threshold. For example, FIG. 5 is a timing chart showing voltages applied to the selection electrodes 40 when there are three selection electrodes 40. In FIG. 4, since the voltage of the selection electrode 40 in the first column is the selection voltage S in the designated period A, the selection electrode 40 in the first column is designated, and the selection electrode 40 in the first column and each data The EL layer 50 sandwiched between the electrodes 30 emits light. In the designated period B, since the voltage of the selection electrode 40 in the second column is the selection voltage S, the selection electrode 40 in the second column is designated.

  On the other hand, when the plurality of selection electrodes 40 are anodes, the selection voltage S of the designated selection electrode 40 among the plurality of selection electrodes 40 is a high voltage, and the other non-designation selection electrodes 40 are relatively lower than the selection voltage S. A non-selection voltage N is applied. In either case, the selection voltage S is a voltage generated in the EL layer 50 that exceeds the light emission threshold with the data electrode 30, and the non-selection voltage N is a voltage that does not exceed the light emission threshold with the data electrode 30. (For example, 0 V) is a voltage generated in the EL layer 50.

  In this exposure panel 20, if the EL layer 50 overlapped with the designated selection electrode 40 has a significantly reduced light emission luminance when a predetermined voltage is applied, if the other selection electrode 40 is designated, The EL layer 50 sandwiched between the data electrodes 30 emits light. By switching the selection electrode 40 designated in this way, the life of the exposure panel 20 can be extended. Even if an EL layer 50 with poor light emission occurs, exposure can be performed by designating another selection electrode without designating the selection electrode 50 of the defective EL layer 50. Leads to improved yield. In addition, in order to improve that the EL layer 50 generates heat and deteriorates due to continuous light emission, the designation of the same selection electrode 40 may be divided so as not to be continued for a long time. Note that the image forming apparatus 1 may be provided with an optical sensor for detecting a decrease in light emission luminance or a light emission failure.

  Next, an operation method of the image forming apparatus 1 and an operation method of the exposure panel 20 will be described. Since there are six types of operation methods, each will be described.

(1) First Operation Method The first operation method is a method of switching the designated selection electrode 40 for each page of the number of printed sheets.
First, one selection electrode 40 (for example, the selection electrode 40 in the first column) is designated from among the plurality of selection electrodes 40 by the switching unit 16 of the drive control unit 15, and the selection is performed until the image of one sheet 99 is completed. The designated selection electrode 40 is designated, and the organic EL element 52 of the designated selection electrode 40 continues to emit light for one page. Then, the photosensitive drum 2, the charging roller 3, the developing roller 6, the transfer roller 7, and the fixing rollers 8 and 9 rotate, the eraser light source 11 emits light, and the paper 99 is conveyed by the conveying belt 12. The grayscale data sequentially input by the drive control unit 15 is sequentially converted from digital to analog by the DAC 17 and a light emission signal is output to the data electrode 30. Thus, the EL layer 50 sandwiched between the designated selection electrode 40 and each data electrode 30 emits light with an intensity according to the gradation data. As a result, an image is formed on the paper 99. When the image formation on the paper 99 is completed, the designated selection electrode 40 is switched, and for example, the designated period A in FIG. That is, when the image formation on the paper 99 is completed, the switching unit 16 of the drive control unit 15 designates a selection electrode 40 in another column (for example, the selection electrode 40 in the second column) from the plurality of selection electrodes 40, The next paper 99 is image-formed. Here, one dot of the minimum unit to be latent image in one rotation of the photosensitive drum 2, that is, one dot of the minimum unit printed on the paper 99, includes the data electrode 30 and the designated selection electrode 40. Only one light emission of the one organic EL element 52 in the meantime is irradiated (or one no light emission), and multiple exposure is not performed for one dot. In this way, when the selection electrode 40 has three rows, the first row, the second row, the third row, the first row, the second row,... Are sequentially switched. That is, when the selection electrodes 40 are N columns (N is an integer of 2 or more), the organic EL elements 52 corresponding to the selection electrodes 40 in the i-th column (1 ≦ i ≦ N) Designation period of the selection electrode 40 of the eye, designation period of the selection electrode 40 of the (i + 2) column,..., Designation of the (N-1) column of the designation period of the selection electrode 40 of the (i-1) column. You can pause without emitting light for a period of time.

  Even if continuous printing is performed by switching the designation for each sheet of paper 99, the organic EL element 52 is prevented from being overheated, leading to a longer life of the exposure panel 20.

(2) Second Operation Method The second operation method is a method of switching the designated selection electrode 40 every predetermined number of pages by page count.
First, one selection electrode 40 is designated from among the plurality of selection electrodes 40 by the switching unit 16 of the drive control unit 15, and the designated selection electrode 40 is continuously designated until the image of a predetermined number of sheets of paper 99 is completed. Then, the photosensitive drum 2, the charging roller 3, the developing roller 6, the transfer roller 7, and the fixing rollers 8 and 9 rotate, the eraser light source 11 emits light, and the paper 99 is conveyed by the conveying belt 12. Then, the grayscale data sequentially input by the drive control unit 15 is sequentially digital-analog converted by the DAC 17, and the grayscale data is output to the data electrode 30. As a result, the EL layer 50 sandwiched between the designated selection electrode 40 and each data electrode 30 emits light with an intensity according to the gradation data, and an image is formed on the paper 99. When the image formation on the paper 99 is completed, the next paper 99 is conveyed by the conveyance belt 12, and then the image formation is repeated. When the image formation is completed for the predetermined number of sheets of paper 99, the designated selection electrode 40 is switched, for example, the designated period A in FIG. That is, when the image formation is completed for a predetermined number of sheets of paper 99, another selection electrode 40 is designated from among the plurality of selection electrodes 40 by the switching unit 16 of the drive control unit 15, and the image of the next predetermined number of sheets of paper 99 is continuously selected. Formation takes place. Here, the image formation of a predetermined number of sheets of paper 99 may be performed continuously or intermittently. The number of sheets of paper 99 on which images are formed is counted by a counter.
Note that the predetermined number may be set as the expected life number. That is, the expected number of times that the EL layer 50 is expected to reach the lifetime may be set to the predetermined number. Here, one dot of the minimum unit to be latent image in one rotation of the photosensitive drum 2, that is, one dot of the minimum unit printed on the paper 99, includes the data electrode 30 and the designated selection electrode 40. Only one light emission of the one organic EL element 52 in the meantime is irradiated (or one no light emission), and multiple exposure is not performed for one dot. In this way, when the selection electrode 40 has three rows, the first row, the second row, the third row, the first row, the second row,... Are sequentially switched. That is, when the selection electrode 40 has N columns (N is an integer of 2 or more), the organic EL elements 52 corresponding to the selection electrodes 40 in the i-th column (1 ≦ i ≦ N) Designation period of the selection electrode 40 of the eye, designation period of the selection electrode 40 of the (i + 2) th column, ..., designation of the (N-1) th column of the designation period of the selection electrode 40 of the (i-1) th column. You can pause without emitting light for a period of time.

(3) Third Operation Method The third operation method is a method of switching the designated selection electrode 40 when a predetermined number of images are formed within a predetermined time.
First, one selection electrode 40 is designated from among the plurality of selection electrodes 40 by the switching unit 16 of the drive control unit 15, and the designated selection electrode 40 is designated until an image of a predetermined number of sheets of paper 99 is completed within a predetermined time. Keep doing. Then, the photosensitive drum 2, the charging roller 3, the developing roller 6, the transfer roller 7, and the fixing rollers 8 and 9 rotate, the eraser light source 11 emits light, and the paper 99 is conveyed by the conveying belt 12. Then, the grayscale data sequentially input by the drive control unit 15 is sequentially digital-analog converted by the DAC 17, and the grayscale data is output to the data electrode 30. As a result, the EL layer 50 sandwiched between the designated selection electrode 40 and each data electrode 30 emits light with an intensity according to the gradation data, and an image is formed on the paper 99. When the image formation on the paper 99 is completed, the next paper 99 is conveyed by the conveyance belt 12, and then the image formation is repeated. Then, when the image formation for a predetermined number of sheets of paper 99 is completed within a predetermined time, the designated selection electrode 40 is switched, and for example, the designated period A in FIG. That is, when image formation is completed within a predetermined time on a predetermined number of sheets of paper 99, another selection electrode 40 is designated from among the plurality of selection electrodes 40 by the switching unit 16 of the drive control unit 15, and then the next predetermined number of sheets The image of the paper 99 is formed. Here, one dot of the minimum unit to be latent image in one rotation of the photosensitive drum 2, that is, one dot of the minimum unit printed on the paper 99, includes the data electrode 30 and the designated selection electrode 40. Only one light emission of the one organic EL element 52 in the meantime is irradiated (or one no light emission), and multiple exposure is not performed for one dot. In this way, when the selection electrode 40 has three rows, the first row, the second row, the third row, the first row, the second row,... Are sequentially switched. That is, when the selection electrodes 40 are N columns (N is an integer of 2 or more), the organic EL elements 52 corresponding to the selection electrodes 40 in the i-th column (1 ≦ i ≦ N) Designation period of the selection electrode 40 of the eye, designation period of the selection electrode 40 of the (i + 2) column,..., Designation of the (N-1) column of the designation period of the selection electrode 40 of the (i-1) column. You can pause without emitting light for a period of time.

(4) Fourth Operation Method The fourth operation method is a method of switching when the EL layer 50 that overlaps the designated selection electrode 40 reaches a predetermined temperature. The image forming apparatus 1 is provided with a temperature sensor that measures the temperature of the organic EL element 52.
First, one selection electrode 40 is designated from among the plurality of selection electrodes 40 by the switching unit 16 of the drive control unit 15. Then, the photosensitive drum 2, the charging roller 3, the developing roller 6, the transfer roller 7, and the fixing rollers 8 and 9 rotate, the eraser light source 11 emits light, and the paper 99 is conveyed by the conveying belt 12. Then, the grayscale data sequentially input by the drive control unit 15 is sequentially digital-analog converted by the DAC 17, and the grayscale data is output to the data electrode 30. As a result, the EL layer 50 sandwiched between the designated selection electrode 40 and each data electrode 30 emits light with an intensity according to the gradation data, and an image is formed on the paper 99. When the image formation on the paper 99 is completed, the next paper 99 is transported by the transport belt 12 and the image formation is repeated. As described above, when the temperature sensor detects that the EL layer 50 overlapped with the designated selection electrode 40 reaches a predetermined temperature according to light emission during image formation, the designated selection electrode 40 is switched. For example, the designated period A in FIG. That is, when the EL layer 50 overlapped with the designated selection electrode 40 has a predetermined temperature or a predetermined temperature rise, another selection electrode 40 is designated from among the plurality of selection electrodes 40 by the switching unit 16 of the drive control unit 15, and image formation continues. Is done. Here, one dot of the minimum unit to be latent image in one rotation of the photosensitive drum 2, that is, one dot of the minimum unit printed on the paper 99, includes the data electrode 30 and the designated selection electrode 40. Only one light emission of the one organic EL element 52 in the meantime is irradiated (or one no light emission), and multiple exposure is not performed for one dot. In this way, when the selection electrode 40 has three rows, the first row, the second row, the third row, the first row, the second row,... Are sequentially switched. That is, when the selection electrodes 40 are N columns (N is an integer of 2 or more), the organic EL elements 52 corresponding to the selection electrodes 40 in the i-th column (1 ≦ i ≦ N) Designation period of the selection electrode 40 of the eye, designation period of the selection electrode 40 of the (i + 2) column,..., Designation of the (N-1) column of the designation period of the selection electrode 40 of the (i-1) column. You can pause without emitting light for a period of time.

(5) Fifth Operation Method The fifth operation method is a method of switching when the applied current decreases to a predetermined threshold during constant voltage driving. In the image forming apparatus 1, an ammeter that detects a current flowing through the organic EL element 52 is connected to a wiring connected to the terminal 31.
First, one selection electrode 40 is designated from among the plurality of selection electrodes 40 by the switching unit 16 of the drive control unit 15. Then, the photosensitive drum 2, the charging roller 3, the developing roller 6, the transfer roller 7, and the fixing rollers 8 and 9 rotate, the eraser light source 11 emits light, and the paper 99 is conveyed by the conveying belt 12. Then, the grayscale data sequentially input by the drive control unit 15 is sequentially digital-analog converted by the DAC 17, and the grayscale data is output to the data electrode 30. As a result, the EL layer 50 sandwiched between the designated selection electrode 40 and each data electrode 30 emits light with an intensity according to the gradation data, and an image is formed on the paper 99. When the image formation on the paper 99 is completed, the next paper 99 is transported by the transport belt 12 and the image formation is repeated. When image formation is performed as described above, when the output of the DAC 17 is a constant voltage output, the ammeter reads the applied current of the DAC 17 and the plurality of organic EL elements 52 corresponding to the designated selection electrodes 40 are read. When it is detected that one of the current values of the respective flowing currents has decreased to a predetermined threshold value, it is considered that the organic EL element 52 has deteriorated, and the designated selection electrode 40 is switched. The designated period A in FIG. When the applied current decreases to a predetermined threshold value, another selection electrode 40 is designated from among the plurality of selection electrodes 40 by the switching unit 16 of the drive control unit 15. Here, one dot of the minimum unit to be latent image in one rotation of the photosensitive drum 2, that is, one dot of the minimum unit printed on the paper 99, includes the data electrode 30 and the designated selection electrode 40. Only one light emission of the one organic EL element 52 in the meantime is irradiated (or one no light emission), and multiple exposure is not performed for one dot. In this way, when the selection electrode 40 has three rows, the first row, the second row, the third row, the first row, the second row,... Are sequentially switched. That is, when the selection electrodes 40 are N columns (N is an integer of 2 or more), the organic EL elements 52 corresponding to the selection electrodes 40 in the i-th column (1 ≦ i ≦ N) Designation period of the selection electrode 40 of the eye, designation period of the selection electrode 40 of the (i + 2) column,..., Designation of the (N-1) column of the designation period of the selection electrode 40 of the (i-1) column. You can pause without emitting light for a period of time.

(6) Sixth Operation Method The sixth operation method is a method of switching when the applied voltage during constant current driving increases to a predetermined threshold value. In the image forming apparatus 1, a voltmeter that detects a voltage applied to the organic EL element 52 is connected to a wiring connected to the lead wiring 41 and a wiring connected to the terminal 31.
First, one selection electrode 40 is designated from among the plurality of selection electrodes 40 by the switching unit 16 of the drive control unit 15. Then, the photosensitive drum 2, the charging roller 3, the developing roller 6, the transfer roller 7, and the fixing rollers 8 and 9 rotate, the eraser light source 11 emits light, and the paper 99 is conveyed by the conveying belt 12. Then, the grayscale data sequentially input by the drive control unit 15 is sequentially digital-analog converted by the DAC 17, and the grayscale data is output to the data electrode 30. As a result, the EL layer 50 sandwiched between the designated selection electrode 40 and each data electrode 30 emits light with an intensity according to the gradation data, and an image is formed on the paper 99. When the image formation on the paper 99 is completed, the next paper 99 is transported by the transport belt 12 and the image formation is repeated. When the image formation is performed as described above, when the output of the DAC 17 is a constant current output, the voltages applied to the plurality of organic EL elements 52 corresponding to the designated selection electrode 40 are read, and these voltages are read. If any of them increases to a predetermined threshold value, it is considered that the organic EL element 52 has deteriorated, and the designated selection electrode 40 is switched. For example, the designated period A in FIG. That is, when the applied voltage to the organic EL element 52 reaches a predetermined threshold value and the resistance is increased, another selection electrode 40 is designated from among the plurality of selection electrodes 40 by the switching unit 16 of the drive control unit 15. Here, one dot of the minimum unit to be latent image in one rotation of the photosensitive drum 2, that is, one dot of the minimum unit printed on the paper 99, includes the data electrode 30 and the designated selection electrode 40. Only one light emission of the one organic EL element 52 in the meantime is irradiated (or one no light emission), and multiple exposure is not performed for one dot. In this way, when the selection electrode 40 has three rows, the first row, the second row, the third row, the first row, the second row,... Are sequentially switched. That is, when the selection electrodes 40 are N columns (N is an integer of 2 or more), the organic EL elements 52 corresponding to the selection electrodes 40 in the i-th column (1 ≦ i ≦ N) Designation period of the selection electrode 40 of the eye, designation period of the selection electrode 40 of the (i + 2) column,..., Designation of the (N-1) column of the designation period of the selection electrode 40 of the (i-1) column. You can pause without emitting light for a period of time.

[Second Embodiment]
FIG. 6 is a plan view of an exposure panel 20A mounted on the housing 14 (shown in FIG. 1) instead of the exposure panel 20 of the first embodiment. FIG. 7 is a cross-sectional view of the surface along the cutting line VII-VII in FIG. FIG. 8 is an equivalent circuit diagram relating to one wiring 131.

  Also in this exposure panel 20 </ b> A, a plurality of data electrodes 30 are patterned on the substrate 21, the data electrodes 30 are covered with an insulating film 60, and a plurality of selection electrodes 40 are patterned on the insulating film 60. In plan view, the data electrode 30 and the selection electrode 40 are orthogonal to each other, an opening 61 is formed at each intersection of the data electrode 30 and the selection electrode 40, and the EL layer 50 is embedded in each opening 61. An EL layer 50 is sandwiched between the electrode 30 and the selection electrode 40. In addition to the data electrode 30, the selection electrode 40, the EL layer 50, the insulating film 60, and the opening 61, the residual layer 51, the sealing material 70, and the sealing plate 80 are also provided as in the first embodiment.

  However, in this embodiment, the data electrode 30 is not exposed from the insulating film 60 and the end of the data electrode 30 is not a terminal for the LSI chip 13. Hereinafter, the difference between the exposure panel 20A and the exposure panel 20 of the first embodiment will be described.

The exposure panel 20A is an active drive exposure apparatus, and one lighting drive circuit is provided for each data electrode 30. As shown in FIG. 8, the lighting driving circuit includes n-channel thin film transistors 101 and 102 and a capacitor 103, respectively. The thin film transistor 101 has a gate connected to the scanning line 104, a drain connected to the wiring 131, and a source connected to the gate of the thin film transistor 102. The thin film transistor 102 has a drain connected to the power supply line 105 and a source connected to the data electrode 30. The capacitor 103 has one end connected to the gate of the thin film transistor 102 and the other end connected to the source of the thin film transistor 102. Here, each wiring 131 corresponds to four lighting driving circuits, and each wiring 131 is branched into four, and each is connected to the drain of the thin film transistor 101 of the lighting driving circuit.
In each lighting drive circuit, the source of the thin film transistor 102 is connected in parallel with the three organic EL elements 52 provided on one data electrode 30. The cathodes of the three organic EL elements 52 in each row are respectively connected to the selection electrodes 40 in each column.
The scanning line 104 is formed by patterning the gate metal of the thin film transistors 101 and 102, and the power supply line 105 is formed by patterning the source and drain metals of the thin film transistors 101 and 102. The scanning line 104 and the power supply line 105 are parallel to the selection electrode 40. A terminal 104 a is provided at the end of the scanning line 104, a terminal 105 a is provided at the end of the power supply line 105, and the terminal 104 a and the terminal 105 a are arranged in a line along the edge of the substrate 21.

  FIG. 9 is a plan view relating to the two wirings 131, and shows a space between the wiring 131 and the end portion of the data electrode 30. The thin film transistors 101 and 102 include a gate on the substrate 21, a gate insulating film covering the gate, a semiconductor film facing the gate on the gate insulating film, an impurity semiconductor film formed on both sides of the semiconductor film, and one impurity An inverted staggered thin film transistor including a source formed on a semiconductor film and a drain formed on the other impurity semiconductor film. In FIG. 9, illustration of the impurity semiconductor, the semiconductor, and the impurity semiconductor film interposed between the source and the drain on the gate insulating film is omitted to simplify the drawing.

  The gates of the thin film transistors 101 and 102, the scanning lines 104, and the power supply lines 105 are formed on the substrate 21 and covered with a gate insulating film. The source / drain of the thin film transistors 101 and 102 are covered with an insulating film 60 and further covered with a sealing material 70.

  The gate of the thin film transistor 101 is formed integrally with the scanning line 104. One of the source and the drain of the thin film transistor 101 is formed integrally with the wiring 131, and the other is connected to the gate of the thin film transistor 102 through the contact hole 106. The contact hole 106 is formed in the gate insulating film.

  The gate of the thin film transistor 102 is integrated with one electrode of the capacitor 103. One of the source and drain of the thin film transistor 102 is connected to the power supply line 105 through the contact hole 107, and the other is integrated with the other electrode of the capacitor 103 and connected to the data electrode 30 through the contact hole 108. Has been. The capacitor is configured by interposing a gate insulating film between one electrode and the other electrode.

Next, an operation method of the exposure panel 20A will be described with reference to FIG.
One of the plurality of selection electrodes 40 is designated by the drive control unit 15, and the photosensitive drum 2, the charging roller 3, the developing roller 6, the transfer roller 7, and the fixing rollers 8 and 9 rotate, and the eraser light source 11 emits light, and the paper 99 is transported by the transport belt 12. For example, when these selection electrodes 40 are cathodes, as shown in FIG. 10, in the designated period A in which the selection electrode 40 in the first column is designated, the voltage of the selection electrode 40 is the selection voltage S (low level). It is.

  When any one of the selection electrodes 40 is designated, a plurality of scanning lines 104 are sequentially selected in synchronization with the horizontal synchronization signal (HSYNC) (in FIG. 10, they are sequentially selected from the first column), and finally After the scanning line 104 (fourth column in FIG. 10) is selected, the first scanning line 104 (first column in FIG. 10) is selected again, and the plurality of scanning lines 104 are sequentially selected. In FIG. 10, C represents one selection period of the scanning line 104. When the selection electrode 40 is a cathode, an on-level high voltage H is applied to the selected scanning line 104, and an off-level low voltage L is applied to the unselected scanning line 104. During the selection period C, a light emission signal is output from the wiring 131 to the selected scanning line 104 and the unselected scanning line 104, but only the thin film transistor 101 connected to the selected scanning line 104 is the thin film transistor 102. The light emission signal voltage is output to the gate.

  In synchronization with the sequential selection of the plurality of scanning lines 104, the plurality of power supply lines 105 are also sequentially selected (in FIG. 10, the first column is selected in order), and the last (fourth column in FIG. 10) supply. After the electric wire 105 is selected, the first feeder line 105 (first row in FIG. 10) is selected again, and the sequential selection of the plurality of feeder lines 105 is repeated. Here, the selection period D of the power supply line 105 is longer than the selection period C of the scanning line 104. When any one of the scanning lines 104 is selected, the voltage of the power supply line 105 related to the scanning line 104 is Before the scanning line 104 is selected, the voltage of the power supply line 105 related to the scanning line 104 becomes a low level lower than the threshold value of the thin film transistor 102 before the scanning line 104 is selected. For this reason, only one organic EL element 52 of the four lighting drive circuits connected to each wiring emits light according to the light emission signal from each wiring 131. That is, in the selection period C of the scanning line of the first column, the thin film transistors 101 in the first row, the fifth row,... (4k-3) row (k is an integer of 1 or more) are selected and The high-level voltage H of the power supply wiring in the first column is applied to the drain of the thin film transistor 102 in the 5th row, 5th row,... (4k-3) row (k is an integer of 1 or more). The organic EL element 52 emits light.

  As described above, when any of the scanning lines 104 is selected (selection period C), the thin film transistor 101 connected thereto is turned on. Further, when any of the scanning lines 104 is selected, gradation data (gradation data represented by the magnitude of voltage is output to the wiring 131 and the gradation data is applied to the capacitor 103 related to the thin film transistor 101 which is turned on. Is stored as an electric charge, and the gradation data is also output to the gate of the thin film transistor 102 of the thin film transistor 101 which is turned on. This current also flows to the EL layer 50 sandwiched between the designated selection electrode 40 and the data electrode 30. Therefore, the organic EL element 52 emits light. The thin film transistor 101 connected to the scanning line 104 is turned off and held in the capacitor 103. Since the line 105 still maintains the high level voltage H, the organic EL element 52 continues to emit light, that is, the organic EL element sandwiched between the designated selection electrode 40 and the data electrode 30 during the selection period D. 52 emits light.

  As described above, all the EL layers 50 under the designated selection electrode 40 emit light once after the first scanning line 104 is selected and until the last scanning line 104 is selected. An image for one line is formed. Then, a two-dimensional image of one sheet of paper 99 is formed by repeating the sequential selection of the plurality of scanning lines 104 while the sheet 99 is being conveyed. In the case of forming an image on a plurality of sheets of paper 99, the paper 99 is sequentially transported by the transport belt 12, and the same operation is performed on the exposure panel 20A.

  Here, the timing of switching the designated selection electrode 40 is the same as any one of the first to sixth operation methods in the first embodiment.

The present invention is not limited to the above-described embodiments, and various improvements and design changes may be made without departing from the spirit of the present invention.
In each of the above embodiments, the electrostatic latent image is formed on the photosensitive drum 2 by the exposure panels 20 and 20A. However, for example, even if the latent image is directly formed on the photosensitive film by the exposure panels 20 and 20A as described above. Good. When the photosensitive film on which the latent image is formed is chemically or thermally developed, the image becomes obvious.

  Further, as shown in the plan view of FIG. 11, a plurality of bypass lines 140 may be formed on the insulating film 60. These bypass lines 140 are provided in parallel to the selection electrodes 40, and the number of bypass lines 140 is the same as the number of selection electrodes 40. A plurality of connection lines 141 parallel to the data electrode 30 are formed under the insulating film 60, and one end of the connection line 141 is connected to the selection electrode 40 via the contact hole 142. The other end of 141 is connected to the selection electrode 40 through a contact hole 143. As a result, one bypass line 140 is conducted per one selection electrode 40. Since the bypass line 140 is electrically connected to the selection electrode 40, the bypass line 140 assists the conduction of the selection electrode 40 even when the width of the selection electrode 40 is narrow and the resistance of the selection electrode 40 is high. Therefore, the width of the selection electrode 40 can be narrowed, and many selection electrodes 40 can be patterned in a narrow region. If the number of the selection electrodes 40 is increased, the lifetime of the exposure panels 20 and 20A can be extended. Further, since the width of the selection electrode 40 becomes narrow, a plurality of selection electrodes 40 can be formed in a narrower region, and the light transmission efficiency of the EL layer 50 by the imaging optical system 4 is uniform for any selection electrode 40. Can be. The bypass line 140 can be used for both the exposure panel 20 in the first embodiment and the exposure panel 20A in the second embodiment.

1 is a schematic side view of an image forming apparatus according to a first embodiment of the present invention. It is a top view of the exposure panel in 1st embodiment of this invention. It is arrow sectional drawing of the surface along the cutting line III-III of FIG. 2 is a block diagram illustrating a circuit provided in the image forming apparatus. FIG. It is a timing chart of the voltage applied in order to specify a selection electrode. It is a top view of the exposure panel in 2nd embodiment of this invention. It is arrow sectional drawing of the surface along the cutting line VII-VII of FIG. 3 is an equivalent circuit between a wiring 131 and three lead wirings 41. FIG. 4 is a plan view showing a space between a wiring 131 and an end of the data electrode 30. FIG. It is a timing chart of the voltage applied to a selection electrode, a scanning line, and a feed line. It is a top view of the modification of the exposure panel in 1st embodiment and 2nd embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 20 Exposure panel 30 Data electrode 40 Selection electrode 50 Electroluminescence layer 101 Thin film transistor 102 Thin film transistor 103 Capacitor

Claims (19)

In an exposure apparatus that is provided in an image forming apparatus that forms an image on a recording medium and that exposes a photoreceptor,
A plurality of data electrodes provided for each of a plurality of rows parallel to the moving direction of the photosensitive member;
A plurality of selection electrodes provided for each of a plurality of rows;
An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of the data electrode and the selection electrode,
During the image formation on the recording medium, any one of the plurality of selection electrodes is designated, and the other row of selection electrodes is not designated, and the EL of the row connected to the designated selection electrode An exposure apparatus characterized in that an image is formed on one recording medium only by elements, and the designation of a selection electrode is switched to a selection electrode in another column every time image formation is completed. In an exposure apparatus that is provided in an image forming apparatus that forms an image on a recording medium and that exposes a photoreceptor,
A plurality of data electrodes provided for each of a plurality of rows parallel to the moving direction of the photosensitive member;
A plurality of selection electrodes provided for each of a plurality of rows;
An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of the data electrode and the selection electrode,
One of the plurality of selection electrodes is designated during image formation on the recording medium, and the image formation on the plurality of recording media is performed only by the EL elements in the row connected to the designated selection electrode. An exposure apparatus characterized in that the designation of a selection electrode is switched to a selection electrode in another column every time image formation on the recording medium is completed. In an exposure apparatus that is provided in an image forming apparatus that forms an image on a recording medium and that exposes a photoreceptor,
A plurality of data electrodes provided for each of a plurality of rows parallel to the moving direction of the photosensitive member;
A plurality of selection electrodes provided for each of a plurality of rows;
An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of the data electrode and the selection electrode,
During the image formation on the recording medium, any one of the plurality of selection electrodes is designated, and the other row of selection electrodes is not designated, and the EL of the row connected to the designated selection electrode Image formation of the recording medium is performed only by the element,
An exposure apparatus characterized in that designation of a selection electrode is switched to a selection electrode in another column every time image formation on a predetermined number of recording media is completed within a predetermined period. In an exposure apparatus that is provided in an image forming apparatus that forms an image on a recording medium and that exposes a photoreceptor,
A plurality of data electrodes provided for each of a plurality of rows parallel to the moving direction of the photosensitive member;
A plurality of selection electrodes provided for each of a plurality of rows;
An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of the data electrode and the selection electrode,
During the image formation on the recording medium, any one of the plurality of selection electrodes is designated, and the other row of selection electrodes is not designated, and the EL of the row connected to the designated selection electrode Image formation of the recording medium is performed only by the element,
An exposure apparatus characterized in that when an EL element corresponding to a designated selection electrode reaches a predetermined temperature, designation of the selection electrode is switched to a selection electrode in another column.   When the EL element overlapped with the designated selection electrode reaches the predetermined temperature during the image formation of the recording medium, the designation of the selection electrode is changed to the selection electrode of another row after the image formation of the recording medium is completed. The exposure apparatus according to claim 4, wherein the exposure apparatus is switched. In an exposure apparatus that is provided in an image forming apparatus that forms an image on a recording medium and that exposes a photoreceptor,
A plurality of data electrodes provided for each of a plurality of rows parallel to the moving direction of the photosensitive member;
A plurality of selection electrodes provided for each of a plurality of rows;
An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of the data electrode and the selection electrode,
During the image formation on the recording medium, any one of the plurality of selection electrodes is designated, and the other row of selection electrodes is not designated, and the EL of the row connected to the designated selection electrode Image formation of the recording medium is performed only by the element,
An exposure apparatus, wherein when a current applied to the EL element decreases to a predetermined value due to deterioration of the EL element over time, the designation of the selection electrode is switched to a selection electrode in another column.   When the timing at which the applied current applied to the plurality of data electrodes decreases to a predetermined value is during the image formation of the recording medium, the selection of the other electrode is selected as the selection electrode after the image formation of the recording medium is completed. The exposure apparatus according to claim 6, wherein the exposure apparatus is switched to an electrode. In an exposure apparatus that is provided in an image forming apparatus that forms an image on a recording medium and that exposes a photoreceptor,
A plurality of data electrodes provided for each of a plurality of rows parallel to the moving direction of the photosensitive member;
A plurality of selection electrodes provided for each of a plurality of rows;
An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of the data electrode and the selection electrode,
During the image formation on the recording medium, any one of the plurality of selection electrodes is designated, and the other row of selection electrodes is not designated, and the EL of the row connected to the designated selection electrode Image formation of the recording medium is performed only by the element,
An exposure apparatus, wherein when a voltage applied to the EL element increases to a predetermined value due to deterioration of the EL element over time, the designation of the selection electrode is switched to a selection electrode in another column.   When the timing at which the applied voltage applied to the plurality of data electrodes increases to a predetermined value is during the image formation of the recording medium, the selection of the other electrode is the designation of the selection electrode after the image formation of the recording medium is completed. The exposure apparatus according to claim 8, wherein the exposure apparatus is switched to an electrode. In an exposure apparatus that is provided in an image forming apparatus that forms an image on a recording medium and that exposes a photoreceptor,
A plurality of data electrodes provided for each of a plurality of rows parallel to the moving direction of the photosensitive member;
A plurality of selection electrodes provided for each of a plurality of rows;
An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of the data electrode and the selection electrode,
During the image formation on the recording medium, any one of the plurality of selection electrodes is designated, and the other row of selection electrodes is not designated, and the EL of the row connected to the designated selection electrode Image formation of the recording medium is performed only by the element,
An exposure apparatus characterized in that each time the image forming apparatus is activated, the designation of a selection electrode is switched to a selection electrode in another column.   The exposure apparatus according to claim 1, wherein a lighting drive circuit including a plurality of transistors is connected to the data electrode. A photoreceptor,
An image forming apparatus comprising: the exposure apparatus according to claim 1. In an operation method of an exposure apparatus provided in an image forming apparatus for forming an image on a recording medium and exposing a photosensitive member,
The exposure apparatus includes a plurality of data electrodes provided for each of a plurality of columns parallel to a direction in which the photosensitive member moves, a plurality of selection electrodes provided for each of a plurality of rows, the data electrodes, and the selection electrodes. An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of
During the image formation on the recording medium, any one of the plurality of selection electrodes is designated, and the other row of selection electrodes is not designated, and the EL of the row connected to the designated selection electrode Image formation of the recording medium is performed only by the element,
A method of operating an exposure apparatus, wherein the designation of a selection electrode is switched to a selection electrode in another column every time image formation on one recording medium is completed. In an operation method of an exposure apparatus provided in an image forming apparatus for forming an image on a recording medium and exposing a photosensitive member,
The exposure apparatus includes a plurality of data electrodes provided for each of a plurality of columns parallel to a direction in which the photosensitive member moves, a plurality of selection electrodes provided for each of a plurality of rows, the data electrodes, and the selection electrodes. An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of
During the image formation on the recording medium, any one of the plurality of selection electrodes is designated, and the other row of selection electrodes is not designated, and the EL of the row connected to the designated selection electrode Image formation of the recording medium is performed only by the element,
A method of operating an exposure apparatus, wherein the designation of a selection electrode is switched to a selection electrode in another column every time image formation on a plurality of recording media is completed. In an operation method of an exposure apparatus provided in an image forming apparatus for forming an image on a recording medium and exposing a photosensitive member,
The exposure apparatus includes a plurality of data electrodes provided for each of a plurality of columns parallel to a direction in which the photosensitive member moves, a plurality of selection electrodes provided for each of a plurality of rows, the data electrodes, and the selection electrodes. An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of
During the image formation on the recording medium, any one of the plurality of selection electrodes is designated, and the other row of selection electrodes is not designated, and the EL of the row connected to the designated selection electrode Image formation of the recording medium is performed only by the element,
An operation method of an exposure apparatus, characterized in that the designation of a selection electrode is switched to a selection electrode in another column every time image formation on a predetermined number of recording media is completed within a predetermined period. In an operation method of an exposure apparatus provided in an image forming apparatus for forming an image on a recording medium and exposing a photosensitive member,
The exposure apparatus includes a plurality of data electrodes provided for each of a plurality of columns parallel to a direction in which the photosensitive member moves, a plurality of selection electrodes provided for each of a plurality of rows, the data electrodes, and the selection electrodes. An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of
During the image formation on the recording medium, any one of the plurality of selection electrodes is designated, and the other row of selection electrodes is not designated, and the EL of the row connected to the designated selection electrode Image formation of the recording medium is performed only by the element,
A method of operating an exposure apparatus, characterized in that, when an electroluminescent layer overlapping a designated selection electrode reaches a predetermined temperature, designation of the selection electrode is switched to a selection electrode in another column. In an operation method of an exposure apparatus provided in an image forming apparatus for forming an image on a recording medium and exposing a photosensitive member,
The exposure apparatus includes a plurality of data electrodes provided for each of a plurality of columns parallel to a direction in which the photosensitive member moves, a plurality of selection electrodes provided for each of a plurality of rows, the data electrodes, and the selection electrodes. An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of
During the image formation on the recording medium, any one of the plurality of selection electrodes is designated, and the other row of selection electrodes is not designated, and the EL of the row connected to the designated selection electrode Image formation of the recording medium is performed only by the element,
A method for operating an exposure apparatus, wherein when a current applied to the EL element decreases to a predetermined value due to deterioration of the EL element over time, a designated selection electrode is switched to a selection electrode in another column. In an operation method of an exposure apparatus provided in an image forming apparatus for forming an image on a recording medium and exposing a photosensitive member,
The exposure apparatus includes a plurality of data electrodes provided for each of a plurality of columns parallel to a direction in which the photosensitive member moves, a plurality of selection electrodes provided for each of a plurality of rows, the data electrodes, and the selection electrodes. An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of
During the image formation on the recording medium, any one of the plurality of selection electrodes is designated, and the other row of selection electrodes is not designated, and the EL of the row connected to the designated selection electrode Image formation of the recording medium is performed only by the element,
The method of operating an exposure apparatus, wherein when the applied voltage applied to the EL element increases to a predetermined value due to deterioration of the EL element over time, the designation of the selection electrode is switched to the selection electrode of another column. In an operation method of an exposure apparatus provided in an image forming apparatus for forming an image on a recording medium and exposing a photosensitive member,
The exposure apparatus includes a plurality of data electrodes provided for each of a plurality of columns parallel to a direction in which the photosensitive member moves, a plurality of selection electrodes provided for each of a plurality of rows, the data electrodes, and the selection electrodes. An EL element having a plurality of electroluminescence layers sandwiched between the data electrode and the selection electrode at each intersection of
During the image formation on the recording medium, any one of the plurality of selection electrodes is designated, and the other row of selection electrodes is not designated, and the EL of the row connected to the designated selection electrode Image formation of the recording medium is performed only by the element,
The method of operating an exposure apparatus, wherein the designation of a selection electrode is switched to a selection electrode in another column each time the image forming apparatus is activated.

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