JP2006100071A - Electrooptical device, image forming device, and image reading device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrooptical device easy to be downsized regarding the electrooptical device or the like provided with a self light emitting element. <P>SOLUTION: The electrooptical device 10 is provided with a transparent substrate 12, a plurality of OLED elements 14 formed on the substrate 12, a sealing body 24 mounted on the substrate 12 so as to seal the OLED elements 14 in collaboration with the substrate 12, and a driver IC, that is, a circuit element 28 arranged to be superposed over the sealing body 24 for driving the OLED elements 14. Because the circuit element 28 is superposed over the sealing body 24, it is possible that the area of the substrate in which the OLED elements 14 are formed can be made smaller. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electro-optical device including a self-luminous element, and an image forming apparatus and an image reading device including the electro-optical device.

  2. Description of the Related Art In recent years, organic light emitting diodes (hereinafter referred to as “OLEDs” where appropriate) called organic electroluminescent elements and light emitting polymer elements have attracted attention as next-generation light emitting devices that replace liquid crystal elements. The OLED element is used as a display device as disclosed in Patent Document 1 and Patent Document 2, for example.

  In addition, an electrophotographic image forming apparatus has been developed that uses a line head in which a large number of OLED elements are arranged as exposure means, that is, a latent image writer. In such a line head, a plurality of pixel circuits including an OLED element and a transistor for driving the OLED element are arranged. For example, Patent Document 3 and Patent Document 4 disclose such a line head.

JP 2000-58255 A JP 2001-343933 A JP 11-27469 A JP 2001-130048 A

  There is a high demand for miniaturization of an electro-optical device including a self-luminous element such as an OLED element. For example, in an electrophotographic image forming apparatus that uses this type of electro-optical device as a line head for writing a latent image, a latent image is written on an image carrier in a limited space between a charger and a developer. There is a need. For this reason, when the line head is large, the line head must be disposed at a position away from the image carrier, and the entire image forming apparatus is also increased in size. By downsizing the electro-optical device, there is a possibility of contributing to downsizing of the entire image forming apparatus.

  However, in the conventional electro-optical device, the arrangement of the constituent elements has been a limitation of downsizing. For example, in the techniques of Patent Document 1 and Patent Document 4, since a circuit element for driving or controlling the OLED element is arranged on the substrate on which the OLED element is formed, it is necessary to use a substrate having a large area.

  Accordingly, the present invention provides an electro-optical device that can be easily reduced in size, and an image forming apparatus and an image reading device including the electro-optical device.

  The electro-optical device according to the present invention includes a substrate, a plurality of self-light-emitting elements formed on the substrate, and a seal attached to the substrate so as to seal the self-light-emitting element in cooperation with the substrate. And a circuit for driving or controlling the self-luminous element, which is disposed so as to overlap the sealing body. According to this arrangement, the circuit for driving or controlling the self-light-emitting element overlaps the sealing body that seals the self-light-emitting element, so that the area of the substrate on which the self-light-emitting element is formed can be reduced. . Accordingly, the substrate can be saved and the entire apparatus including the electro-optical device can be reduced in size.

  In a preferred embodiment, the electro-optical device further includes a second substrate attached to the side opposite to the substrate of the sealing body, the circuit is provided on the second substrate, and the second substrate The substrate is provided with a power line for supplying power to at least one of the circuit and the light-emitting element. A power supply line for supplying power to a large number of self-luminous elements and circuits has a large cross-sectional area because a large current needs to flow. When such a power supply line is provided on a substrate on which a self-light emitting element is formed, a substrate having a large area is required. However, according to this arrangement, since the power supply line for supplying power to at least one of the circuit and the self-light-emitting element is provided on the second substrate on which the circuit is provided, the self-light-emitting element is formed. It is possible to reduce the area of the formed substrate.

  An image forming apparatus according to the present invention includes an image carrier, a charger for charging the image carrier, and a plurality of the self-light emitting elements, and a plurality of the self-light-emitting elements on a charged surface of the image carrier. The electro-optical device that forms a latent image by irradiating light from an element, the developing device that forms a visible image on the image carrier by attaching toner to the latent image, and the developer from the image carrier. A transfer unit that transfers the image to another object. As described above, since the electro-optical device according to the present invention can be reduced in size, the electro-optical device can be disposed near the image carrier, and the image forming apparatus can also be reduced in size.

  An image reading apparatus according to the present invention includes the electro-optical device in which a plurality of the self-light-emitting elements are arranged, and a light-receiving device that converts light emitted from the self-light-emitting elements and reflected by a reading target into an electric signal. . As described above, since the area of the substrate can be reduced in the electro-optical device according to the present invention, the image reading device can also be reduced in size.

  Hereinafter, various embodiments according to the present invention will be described with reference to the accompanying drawings. In the drawings, the ratio of dimensions of each part is appropriately changed from the actual one.

<First Embodiment>
FIG. 1 is a cross-sectional view showing an electro-optical device according to a first embodiment of the invention, and FIG. 2 is a partial plan view of the electro-optical device. This electro-optical device is used as a line-type optical head for writing a latent image on an image carrier in an image forming apparatus using an electrophotographic system. As shown in these drawings, the electro-optical device 10 includes a transparent substrate 12 and a plurality of OLED elements (self-emitting elements) 14 formed on the substrate 12. The substrate 12 is preferably a flat plate made of glass, quartz, or plastic, and a large number of OLED elements (self-emitting elements) 14 are arranged on the substrate 12 in a row or other appropriate pattern. In the illustrated form, light emitted from each OLED element 14 passes through the transparent substrate 12 and travels downward in FIG. That is, this electro-optical device is a bottom emission type.

  On the substrate 12, electrodes 18A and 18B for supplying power to the OLED element 14 and wiring 16 for connecting the OLED element 14 and the electrodes 18A and 18B are formed. Further, power lines 20A, 20B, and 20C are formed on the substrate 12 to drive the OLED element 14. The wiring 16, the electrodes 18A and 18B, and the power supply lines 20A, 20B, and 20C are made of a conductive material such as aluminum.

  Further, a sealing body 24 is attached to the substrate 12 so as to seal these OLED elements 14 in cooperation with the substrate 12. This sealing isolates the OLED element 14 from the outside air, particularly moisture and oxygen, and suppresses its deterioration. The sealing body 24 can be formed of, for example, glass, metal, ceramic, or plastic. An adhesive 22 is preferably used for attaching the sealing body 24 to the substrate 12. As the adhesive, for example, a thermosetting adhesive or an ultraviolet curable adhesive is used.

  The types of sealing used in the field of OLED include film sealing in which the entire surface of the sealing body 24 is bonded to the substrate 12 by the adhesive 22 and the peripheral portion of the sealing body 24 by the adhesive 22. There is a cap sealing that provides a space defined by the sealing body 24 and the substrate 12 around the OLED element 14. In the cap sealing, a desiccant is disposed in this space. This embodiment may use either film sealing or cap sealing. One or more passivation layers may be provided around the sealing body 24 in order to further protect the OLED element 14 from the outside air.

  Furthermore, a driver IC, that is, a circuit element 28 for driving the plurality of OLED elements 14 is attached on the sealing body 24. An adhesive 26 is preferably used for attaching the circuit element 28 to the sealing body 24. As the adhesive, for example, a thermosetting adhesive or an ultraviolet curable adhesive is used.

  As will be described later, the circuit element 28 includes a wiring for supplying power to the plurality of OLED elements 14 and an element for switching on / off the energization of these OLED elements 14. The circuit element 28 has electrodes 30A, 30B, 32A, 32B, and 32C on its upper surface. The electrodes 30A and 30B are connected to the electrodes 18A and 18B on the substrate 12 via bonding wires 34A and 34B, respectively, and finally connected to the cathode and the anode of the OLED element 14, respectively. The electrodes 32A, 32B, and 32C are connected to the power supply lines 20A, 20B, and 20C through bonding wires 36A, 36B, and 36C, respectively.

  The power line 20A is a common low potential power line for the OLED element 14 and the circuit element 28. The power supply line 20 </ b> B is a high potential power supply line for the OLED element 14. The power supply line 20C is a high potential power supply line for the circuit element 28. These power supply lines 20A, 20B, and 20C are connected to a power supply device via a flexible substrate (not shown).

FIG. 3 is a cross-sectional view showing details of each OLED element 14. The OLED element 14 includes a hole injection layer 46 formed on a transparent anode 42 made of ITO (Indium Tin Oxide), a light emitting layer 48 formed thereon, and a cathode formed thereon. 49. The hole injection layer 46 and the light emitting layer 48 are formed in a recess defined by the insulating layer 40 and the partition wall 44. The material of the insulating layer 40 is, for example, SiO ₂ , and the material of the partition wall 44 is, for example, polyimide.

  The anode 42 is connected to the electrode 18B via a conductor not shown in FIG. 3. Although not shown in detail in FIG. 3, the cathode 49 is connected to the electrode 18A behind the electrode 18B via a conductor. Has been. These leads are shown schematically as wiring 16 in FIG. The configuration of each OLED element 14 of this embodiment is as described above, but variations of the OLED element according to the present invention include a type in which an electron injection layer is provided between a cathode and a light emitting layer, and an anode and a transparent substrate. It may be a type having another layer such as a type in which an insulating layer is provided between them.

  FIG. 4 is a block diagram illustrating a drive system of the electro-optical device 10. As shown in FIG. 4, the circuit element 28 described above includes a plurality of, for example, 128 data lines L0 to L127 and a drive circuit 280. In addition to the data signals D0 to D127, the circuit element 28 is supplied with various control signals CTL, a first power supply potential VIC, and a ground potential GND. Data signals D0 to D127 are applied to data lines L0 to L127 from a data control circuit (not shown). The first power supply potential VIC is supplied from the high potential power supply line 20C for the circuit element 28, and the ground potential GND is supplied from the common low potential power supply line 20A for the OLED element 14 and the circuit element 28.

  Each of the pixel blocks B1 to B40 shown in FIG. 4 is a set of a plurality of, for example, 128 pixel circuits P that are driven in one unit time. The drive circuit 280 is supplied with a clock signal as the control signal CTL, and the drive circuit 280 sequentially outputs selection signals SEL1 to SEL40 according to the clock signal. The selection signals SEL1 to SEL40 are input to the pixel blocks B1 to B40, respectively, and are supplied to 128 pixel circuits P in the corresponding pixel block. Each of the selection signals SEL1 to SEL40 becomes active for a period (selection period) of 1/40 of the main scanning period for latent image writing.

  The first to forty pixel blocks B1 to B40 are exclusively and sequentially selected by the selection signals SEL1 to SEL40. In this way, the main scanning period is divided into a plurality of selection periods (writing periods), and the pixel blocks B1 to B40 are driven in a time-sharing manner. Therefore, a dedicated data line is provided for each of the 5120 (128 × 40) pixel circuits P. The number of data lines can be reduced. That is, 5120 pixel circuits P can be controlled by 128 data lines L0 to L127. Each of the first to fourth pixel blocks B1 to B40 includes 128 pixel circuits P corresponding to the data lines L0 to L127, respectively. These pixel circuits P are supplied with the second power supply potential VEL and the ground potential GND. The second power supply potential VEL is supplied from the high potential power supply line 20B for the OLED element 14, and the ground potential GND is supplied from the common low potential power supply line 20A for the OLED element 14 and the circuit element 28. Then, the data signals D0 to D127 supplied via the data lines L0 to L127 in each selection period are taken into the pixel circuit P. The data signals D0 to D127 in this example are binary signals for instructing to turn on / off the OLED element.

  FIG. 5 is a circuit diagram of each pixel circuit P. Each pixel circuit P includes a holding transistor 281, a driving transistor 282, and the OLED element 14. In the figure, the part built in the circuit element 28 is denoted by reference numeral 28. As is clear from this, the holding transistor 281 and the driving transistor 282 are built in the circuit element 28. One of the selection signals SEL1 to SEL40 is supplied from the driving circuit 280 to the gate of the holding transistor 281 and the source thereof is connected to one of the data lines L0 to L127, so that one of the data signals D0 to D127 becomes the source. Supplied. The drain of the holding transistor 281 and the gate of the driving transistor 282 are connected by a connection line. A stray capacitance is attached to the connection line, and this capacitance acts as a holding capacitance. In the storage capacitor, a binary voltage is written in the selection period, and the written voltage is held until the next selection period. Therefore, the OLED element 14 emits light only during a period in which the data signals D0 to D127 are signals for instructing the lighting of the OLED element 14 in the period in which the holding transistors are selected by the selection signals SEL1 to SEL40.

  The second power supply potential VEL is supplied to the drain of the drive transistor 282 from the high potential power supply line 20B through the bonding wire 36B and the electrode 32B of the circuit element 28. The source of the driving transistor 282 is connected to the anode of the OLED element 14 through the electrode 30B of the circuit element 28, the bonding wire 34B, and the electrode 18B on the substrate 12. The drive transistor 282 supplies a drive current corresponding to the voltage (binary value) written in the storage capacitor to the OLED element 14. The ground potential GND is supplied to the cathode of the OLED element 14 from the low potential power line 20A through the bonding wire 36A, the electrode 32A of the circuit element 28, the electrode 30A of the circuit element 28, the bonding wire 34A, and the electrode 18B on the substrate 12. Is done. The OLED element 14 emits an amount of light corresponding to the magnitude of the drive current.

  As described above, the circuit element 28 is instructed whether to drive the OLED element 14 in the selected pixel block and the drive circuit 280 that selects which pixel block can be energized (OLED element). The pixel circuit P (more precisely, the holding transistor 281 and the driving transistor 282) for turning on / off the power supply to 14 is incorporated. However, a circuit equivalent to the drive circuit 280 may be provided outside the circuit element 28, or a control circuit that generates the data signals D0 to D127 or various control signals CTL may be provided inside the circuit element 28. These variations are also within the scope of the present invention. The components of these circuit elements 28 may be provided in one element, that is, an IC chip, or may be distributed to a plurality of elements.

Next, a procedure for manufacturing the electro-optical device 10 according to the first embodiment will be described. First, as shown in FIG. 6, the OLED element 14, the wiring 16, the electrodes 18A and 18B, and the power supply lines 20A, 20B, and 20C are formed on the substrate 12. Although not shown, thereafter, the power supply lines 20A, 20B, and 20C may be protected with an overcoat film. Examples of the overcoat film include a SiO ₂ film, a SiN film, and a combination thereof. These forming methods may be any known method, and the description thereof is omitted.

  Next, as shown in FIG. 7, a thermosetting or ultraviolet curable adhesive 22 for sealing is coated on the substrate 12. Further, as shown in FIG. 8, the sealing body 24 is placed on the adhesive 22 and attached to the substrate 12, and then the adhesive 22 is cured. As shown in FIG. 8, the sealing adhesive 22 has a protruding portion 22 a that protrudes from the space between the substrate 12 and the sealing body 24 and partially covers the side end of the sealing body 24. Also good. By providing such a protrusion 22a, the sealing effect can be further enhanced. In order to provide the protruding portion 22a, an amount of adhesive larger than the amount disposed in the space between the substrate 12 and the sealing body 24 is coated on the substrate 12, and the adhesive protrudes from the space. Alternatively, the adhesive may be further coated on the outside after the adhesive 22 is cured.

  Thereafter, a thermosetting or ultraviolet curable adhesive 26 is coated on the lower surface of the circuit element 28 (the surface opposite to the electrodes 30A, 30B, 32A, 32B, and 32C). And as shown in FIG. 9, the circuit element 28 is affixed on the sealing body 24, and the adhesive agent 26 is hardened after this. Further, as shown in FIGS. 1 and 2, the electro-optical device 10 is completed by attaching the bonding wires 34A, 34B, 36A, 36B, and 36C to the above-described predetermined positions by the wire bonding method.

  According to the arrangement of this embodiment, since the circuit element 28 that drives the OLED element 14 overlaps the sealing body 24 that seals the OLED element 14, the area of the substrate 12 on which the OLED element 14 is formed is reduced. Is possible. Therefore, the substrate 12 can be saved, and the entire apparatus including the electro-optical device 10 can be reduced in size.

<Second Embodiment>
FIG. 10 is a cross-sectional view showing an electro-optical device according to the second embodiment of the invention, and FIG. 11 is a partial plan view of the electro-optical device. This electro-optical device is also used as a line type optical head for writing a latent image on an image carrier in an image forming apparatus using an electrophotographic system. As shown in these drawings, the electro-optical device 50 includes a transparent substrate 52 which is preferably a flat plate formed of glass, quartz or plastic. Similar to the substrate 12 of the first embodiment, a plurality of OLED elements (self-emitting elements) 14 are formed on the substrate 52. This electro-optical device is also a bottom emission type.

  On the substrate 52, electrodes 18A and 18B for supplying power to the OLED element 14 and wirings 16 for connecting the OLED element 14 and the electrodes 18A and 18B are formed. The wiring 16 and the electrodes 18A and 18B are made of a conductive material such as aluminum.

  Similar to the first embodiment, a sealing body 24 formed of, for example, glass, metal, ceramic, or plastic is provided on the substrate 52 so as to seal the OLED element 14 in cooperation with the substrate 52. It is attached by a thermosetting or ultraviolet curable adhesive 22. The type of sealing may be any of the above-described film sealing and cap sealing. One or more passivation layers may be provided around the sealing body 24 in order to further protect the OLED element 14 from the outside air.

  Further, a second substrate 78 is attached on the sealing body 24 by a thermosetting or ultraviolet curable adhesive 66 or other appropriate attachment means. The second substrate 78 may be formed of the same material as the substrate 52, but is preferably a glass epoxy substrate in which a non-woven fabric made of glass is disposed inside an epoxy resin.

  Further, power lines 20A, 20B, and 20C are formed on the second substrate 78 to drive the OLED element 14. The power supply lines 20A, 20B, and 20C are made of a conductive material such as aluminum.

  A driver IC, that is, a circuit element 28 for driving the plurality of OLED elements 14 is mounted on the second substrate 78. An adhesive 80 is preferably used for attaching the circuit element 28 to the sealing body 24. As the adhesive, for example, a thermosetting adhesive or an ultraviolet curable adhesive is used.

  The circuit element 28 is the same as the circuit element 28 described in detail with respect to the first embodiment. As in the first embodiment, the electrodes 30A and 30B of the circuit element 28 are connected to the electrodes 18A and 18B on the substrate 52 via bonding wires 34A and 34B, respectively, and finally the cathode and the OLED element 14 Each is connected to the anode. The electrodes 32A, 32B, 32C of the circuit element 28 are connected to the power supply lines 20A, 20B, 20C via bonding wires 36A, 36B, 36C, respectively.

  The power line 20A is a common low potential power line for the OLED element 14 and the circuit element 28. The power supply line 20 </ b> B is a high potential power supply line for the OLED element 14. The power supply line 20C is a high potential power supply line for the circuit element 28. These power supply lines 20A, 20B, and 20C are connected to a power supply device via a flexible substrate (not shown).

  The details of each OLED element 14 are the same as those described in detail with respect to the first embodiment with reference to FIG. Variations of the OLED elements described above with respect to the first embodiment may be used.

  The drive system of the electro-optical device 50 is the same as the drive system of the electro-optical device 10 described in detail with respect to the first embodiment with reference to FIGS. 4 and 5. Variations of the circuit element 28 described above with respect to the first embodiment may be used.

  Next, a procedure for manufacturing the electro-optical device 50 according to the second embodiment will be described. First, as shown in FIG. 12, the OLED element 14, the wiring 16, and the electrodes 18A and 18B are formed on the substrate 52. These forming methods may be any known method, and the description thereof is omitted.

  Next, as shown in FIG. 13, a sealing thermosetting or ultraviolet curable adhesive 22 is coated on the substrate 52. Further, as shown in FIG. 14, the sealing body 24 is placed on the adhesive 22 and attached to the substrate 52, and then the adhesive 22 is cured. As in the first embodiment, as shown in FIG. 14, the sealing adhesive 22 protrudes from the space between the substrate 52 and the sealing body 24 and partially covers the side end portion of the sealing body 24. You may have the protrusion part 22a which covers it.

  Thereafter, as shown in FIG. 15, the adhesive 66 is coated on the sealing body 24, the second substrate 78 is placed on the adhesive 66 and attached to the sealing body 24, and then the adhesive 66 is cured. Let

Before or after the bonding, power supply lines 20A, 20B, and 20C are formed on the second substrate 78. The power supply lines 20A, 20B, and 20C may be formed by any known method. However, in the case where the second substrate 78 is a glass epoxy substrate, the power supply lines 20A, 20B, and the like using a conductor such as a copper foil as a material by a known printed circuit wiring method (for example, a subtractive method or an active method). A 20C pattern is preferably formed on the second substrate 78. Although not shown, the power supply lines 20A, 20B, and 20C may be protected with an overcoat film. Examples of the overcoat film include a SiO ₂ film, a SiN film, and a combination thereof.

  Further, the circuit element 28 is bonded to the second substrate 78. As shown in FIG. 16, a thermosetting or ultraviolet curable adhesive 80 is coated on the lower surface of the circuit element 28 (the surface opposite to the electrodes 30A, 30B, 32A, 32B, and 32C). Then, the circuit element 28 is attached to the second substrate 78, and then the adhesive 80 is cured. Further, as shown in FIGS. 10 and 11, the electro-optical device 10 is completed by attaching the bonding wires 34A, 34B, 36A, 36B, and 36C to the predetermined positions described above by the wire bonding method.

  In the illustrated embodiment, both end portions of the sealing body 24 and the second substrate 78 are flush with each other, and one side end portion of the substrate 52 is one side of the sealing body 24 and the second substrate 78. It is flush with the edge. However, any one of these members may protrude from another member.

  According to the arrangement of this embodiment, since the circuit element 28 that drives the OLED element 14 is provided on the second substrate 78 that overlaps the sealing body 24 that seals the OLED element 14, the OLED element It is possible to reduce the area of the substrate 52 on which the 14 is formed. Accordingly, the substrate 52 can be saved, and the entire apparatus including the electro-optical device 50 can be reduced in size.

  In addition, a power line for supplying power to a large number of OLED elements and circuit elements has a large cross-sectional area because it needs to pass a large current. When such a power supply line is provided on a substrate on which an OLED element is formed, a substrate having a large area is required. However, according to the arrangement of this embodiment, the power supply lines 20A, 20B, and 20C for supplying power to the circuit element 28 and the OLED element 14 are provided on the second substrate 78 on which the circuit element 28 is provided. Thus, the area of the substrate 52 on which the OLED element 14 is formed can be reduced.

  In the illustrated form, all of the power supply lines 20A, 20B, and 20C are formed on the second substrate 78. However, as a variation of the present invention, any one of the power supply lines 20A, 20B, and 20C is replaced with the substrate 52 or the sealing body 24. The other may be formed on the second substrate 78. Also in this case, the area of the substrate 52 can be reduced by arranging any one of the power supply lines 20A, 20B, and 20C on the sealing body 24 or the second substrate 78.

  When the second substrate 78 is a glass epoxy substrate, the thick power lines 20A, 20B, and 20C are formed by a known printed circuit board wiring method by depositing (evaporating) metal on the glass substrate. Compared with the case where the power supply lines are formed, it is easier to reduce the width of the power supply lines 20A, 20B, and 20C. In the drawing, the widths of the power supply lines 20A, 20B, and 20C are small, but are actually much larger than the width of the OLED element 14. Therefore, by reducing the width of the power supply lines 20A, 20B, and 20C, the areas of the substrate 52, the sealing body 24, and the second substrate 78 can be significantly reduced.

<Image forming apparatus>
As described above, the electro-optical devices 10 and 50 can be used as a line-type optical head for writing a latent image on an image carrier in an image forming apparatus using an electrophotographic system. Examples of the image forming apparatus include a printer, a printing part of a copying machine, and a printing part of a facsimile.

  FIG. 17 is a longitudinal sectional view showing an example of an image forming apparatus using the electro-optical device 10 or 50 as a line type optical head. This image forming apparatus is a tandem type full color image forming apparatus using a belt intermediate transfer body system.

  In this image forming apparatus, four organic EL array exposure heads 10K, 10C, 10M, and 10Y having the same configuration have four photosensitive drums (image carriers) 110K, 110C, 110M, and 110Y having the same configuration. The exposure positions are respectively arranged. The organic EL array exposure heads 10K, 10C, 10M, and 10Y are the electro-optical device 10 or 50 described above.

  As shown in FIG. 17, this image forming apparatus is provided with a driving roller 121 and a driven roller 122, and an endless intermediate transfer belt 120 is wound around these rollers 121 and 122, as indicated by arrows. Thus, the periphery of the rollers 121 and 122 is rotated. Although not shown, tension applying means such as a tension roller that applies tension to the intermediate transfer belt 120 may be provided.

  Around the intermediate transfer belt 120, photosensitive drums 110K, 110C, 110M, and 110Y having photosensitive layers on four outer peripheral surfaces are arranged at predetermined intervals. The subscripts K, C, M, and Y mean that they are used to form black, cyan, magenta, and yellow visible images, respectively. The same applies to other members. The photosensitive drums 110K, 110C, 110M, and 110Y are rotationally driven in synchronization with the driving of the intermediate transfer belt 120.

  Around each photosensitive drum 110 (K, C, M, Y), a corona charger 111 (K, C, M, Y), an organic EL array exposure head 10 (K, C, M, Y), and Developers 114 (K, C, M, Y) are disposed. The corona charger 111 (K, C, M, Y) uniformly charges the outer peripheral surface of the corresponding photosensitive drum 110 (K, C, M, Y). The organic EL array exposure head 10 (K, C, M, Y) writes an electrostatic latent image on the charged outer peripheral surface of the photosensitive drum. In each organic EL array exposure head 10 (K, C, M, Y), the arrangement direction of the plurality of OLED elements 14 is aligned with the bus (main scanning direction) of the photosensitive drum 110 (K, C, M, Y). Installed. The electrostatic latent image is written by irradiating the photosensitive drum with light from the plurality of OLED elements 14. The developing device 114 (K, C, M, Y) forms a visible image, that is, a visible image on the photosensitive drum by attaching toner as a developer to the electrostatic latent image.

  The black, cyan, magenta, and yellow developed images formed by the four-color single-color image forming station are sequentially transferred onto the intermediate transfer belt 120 to be superimposed on the intermediate transfer belt 120. As a result, a full-color visible image is obtained. Four primary transfer corotrons (transfer devices) 112 (K, C, M, Y) are arranged inside the intermediate transfer belt 120. The primary transfer corotron 112 (K, C, M, Y) is disposed in the vicinity of the photosensitive drum 110 (K, C, M, Y), and the photosensitive drum 110 (K, C, M, Y). The electrostatic image is electrostatically attracted from the toner image to transfer the visible image to the intermediate transfer belt 120 passing between the photosensitive drum and the primary transfer corotron.

  A sheet 102 as an object on which an image is to be finally formed is fed one by one from the sheet feeding cassette 101 by the pickup roller 103, and between the intermediate transfer belt 120 and the secondary transfer roller 126 in contact with the driving roller 121. Sent to the nip. The full-color visible image on the intermediate transfer belt 120 is secondarily transferred to one side of the sheet 102 by the secondary transfer roller 126 and fixed on the sheet 102 through the fixing roller pair 127 as a fixing unit. . Thereafter, the sheet 102 is discharged onto a paper discharge cassette formed in the upper part of the apparatus by a paper discharge roller pair 128.

  Since the image forming apparatus of FIG. 17 uses the electro-optical device 10 or 50 having an organic EL array as writing means, the apparatus can be made smaller than when a laser scanning optical system is used. Further, as described above, since the electro-optical device 10 or 50 can be made smaller than the conventional one, the electro-optical device 10 or 50 can be disposed at a position close to the photosensitive drums 110K, 110C, 110M, and 110Y, and the image forming apparatus is also more suitable. It is possible to reduce the size.

Next, another embodiment of the image forming apparatus according to the present invention will be described.
FIG. 18 is a longitudinal sectional view of another image forming apparatus using the electro-optical device 10 or 50 as a line type optical head. This image forming apparatus is a rotary developing type full-color image forming apparatus using a belt intermediate transfer body system. In the image forming apparatus shown in FIG. 18, a corona charger 168, a rotary developing unit 161, an organic EL array exposure head 167, and an intermediate transfer belt 169 are provided around a photosensitive drum (image carrier) 165. Yes.

  The corona charger 168 uniformly charges the outer peripheral surface of the photosensitive drum 165. The organic EL array exposure head 167 writes an electrostatic latent image on the charged outer peripheral surface of the photosensitive drum 165. The organic EL array exposure head 167 is the electro-optical device 10 or 50 described above, and is installed such that the arrangement direction of the plurality of OLED elements 14 is along the bus line (main scanning direction) of the photosensitive drum 165. The electrostatic latent image is written by irradiating the photosensitive drum with light from the plurality of OLED elements 14.

  The developing unit 161 is a drum in which four developing units 163Y, 163C, 163M, and 163K are arranged at an angular interval of 90 °, and can rotate counterclockwise about the shaft 161a. The developing units 163Y, 163C, 163M, and 163K supply yellow, cyan, magenta, and black toners to the photosensitive drum 165, respectively, and attach the toner as a developer to the electrostatic latent image, thereby the photosensitive drum 165. A visible image, that is, a visible image is formed.

  The endless intermediate transfer belt 169 is wound around a driving roller 170a, a driven roller 170b, a primary transfer roller 166, and a tension roller, and is rotated around these rollers in a direction indicated by an arrow. The primary transfer roller 166 transfers the visible image to the intermediate transfer belt 169 that passes between the photosensitive drum and the primary transfer roller 166 by electrostatically attracting the visible image from the photosensitive drum 165.

  Specifically, in the first rotation of the photosensitive drum 165, an electrostatic latent image for a yellow (Y) image is written by the exposure head 167, and a developed image of the same color is formed by the developing unit 163Y. The image is transferred to the transfer belt 169. Further, in the next rotation, an electrostatic latent image for a cyan (C) image is written by the exposure head 167, and a developed image of the same color is formed by the developing device 163C. The intermediate transfer is performed so as to overlap the yellow developed image. Transferred to the belt 169. Then, during the four rotations of the photosensitive drum 9, the yellow, cyan, magenta, and black visible images are sequentially superimposed on the intermediate transfer belt 169. As a result, a full-color visible image is formed on the transfer belt 169. It is formed. When images are finally formed on both sides of a sheet as an object on which an image is to be formed, the same color images of the front and back surfaces are transferred to the intermediate transfer belt 169, and then the front and back surfaces are transferred to the intermediate transfer belt 169. A full-color visible image is obtained on the intermediate transfer belt 169 by transferring the visible image of the next color.

  The image forming apparatus is provided with a sheet conveyance path 174 through which a sheet passes. The sheets are picked up one by one from the paper feed cassette 178 by the pick-up roller 179, advanced through the sheet transport path 174 by the transport roller, and between the intermediate transfer belt 169 and the secondary transfer roller 171 in contact with the drive roller 170a. Pass through the nip. The secondary transfer roller 171 transfers the developed image to one side of the sheet by electrostatically attracting a full-color developed image from the intermediate transfer belt 169 collectively. The secondary transfer roller 171 can be moved closer to and away from the intermediate transfer belt 169 by a clutch (not shown). The secondary transfer roller 171 is brought into contact with the intermediate transfer belt 169 when a full-color visible image is transferred onto the sheet, and is separated from the secondary transfer roller 171 while the visible image is superimposed on the intermediate transfer belt 169.

  The sheet on which the image has been transferred as described above is conveyed to the fixing device 172 and is passed between the heating roller 172a and the pressure roller 172b of the fixing device 172, whereby the visible image on the sheet is fixed. The sheet after the fixing process is drawn into the discharge roller pair 176 and proceeds in the direction of arrow F. In the case of double-sided printing, after most of the sheet passes through the paper discharge roller pair 176, the paper discharge roller pair 176 is rotated in the reverse direction and introduced into the double-sided printing conveyance path 175 as indicated by an arrow G. The Then, the visible image is transferred to the other surface of the sheet by the secondary transfer roller 171, the fixing process is performed again by the fixing device 172, and then the sheet is discharged by the discharge roller pair 176.

  Since the image forming apparatus of FIG. 18 uses the exposure head 167 (electro-optical device 10 or 50) having an organic EL array as writing means, the size of the device is reduced as compared with the case of using a laser scanning optical system. be able to. Further, as described above, since the electro-optical device 10 or 50 can be made smaller than before, it can be arranged at a position close to the photosensitive drum 165, and the image forming apparatus can also be made smaller. It is.

  The image forming apparatus to which the electro-optical device 10 or 50 can be applied has been described above. However, the electro-optical device 10 or 50 can be applied to other electrophotographic image forming apparatuses, and such an image is used. Forming devices are within the scope of the present invention. For example, the electro-optical device 10 or 50 can be applied to an image forming apparatus that directly transfers a visible image from a photosensitive drum to a sheet without using an intermediate transfer belt, or an image forming apparatus that forms a monochrome image. Is possible.

<Image reading device>
The electro-optical devices 10 and 50 can be used as a line-type optical head for irradiating light to a reading target in the image reading device. Examples of the image reading apparatus include a scanner, a reading portion of a copying machine, a reading portion of a facsimile, a barcode reader, and a two-dimensional image code reader that reads a two-dimensional image code such as a QR code (registered trademark).

  FIG. 19 is a longitudinal sectional view showing an example of an image reading apparatus using the electro-optical device 10 or 50 as a line type optical head. A flat platen glass 202 is provided on the upper part of the cabinet 201 of the image reading apparatus, and a document 203 is placed on the platen glass 202 with its image surface facing downward. A platen cover (not shown) presses the document 203 toward the platen glass 202.

  Inside the cabinet 201, a high speed carriage 204 and a low speed carriage 205 are arranged so as to be movable in the horizontal direction. An organic EL array exposure head 206 that irradiates the original 203 and a reflecting mirror 207 are mounted on the high-speed carriage 204, and two reflecting mirrors 208 and 209 are mounted on the low-speed carriage 205. These organic EL array exposure head 206 and reflecting mirrors 207, 208, and 209 extend in the direction perpendicular to the paper surface (main scanning direction) in FIG. The organic EL array exposure head 206 is installed so that the arrangement direction of the plurality of OLED elements 14 is along the main scanning direction.

  A document reader 210 is disposed at a fixed position inside the cabinet 201. The document reader 210 includes an imaging lens 212 and a line sensor (light receiving device) 213 composed of a large number of photosensitive pixels (charge coupled devices). The line sensor 213 extends in the direction perpendicular to the paper surface (main scanning direction) in FIG. 19, and is installed such that the arrangement direction of the plurality of photosensitive pixels is along the main scanning direction.

  Light emitted from the organic EL array exposure head 206 passes through the platen glass 202 and is reflected by the lower surface of the document 203. Reflected light from the original 203 is transmitted through the platen glass 202, reflected by the reflecting mirrors 207 to 209, and then imaged by the line sensor 213 by the imaging lens 212. The high-speed carriage 204 moves in the horizontal direction so that the entire surface of the original 203 is irradiated by the organic EL array exposure head 206, and the low-speed carriage 205 moves at half the speed of the high-speed carriage 204 to The length of the reflected light path reaching 213 is kept constant.

  As described above, the electro-optical device 10 or 50 is used as the organic EL array exposure head 206 which is an illumination device of the image reading device. However, in this type of lighting device, it is preferable that all of the OLED elements 14 in the range corresponding to the width of the document emit light continuously for a long period of time. Therefore, in the drive systems of FIGS. 4 and 5, the pixel blocks B1 to B40 are not time-division driven, but the pixel blocks in the range corresponding to the width of the document are continued for at least the length of the document. Therefore, the selection signal may be given simultaneously. Further, all the data signals D0 to D127 may be turned on simultaneously during that period. Alternatively, the data lines L0 to L127 and the holding transistor 281 that transmit the data signals D0 to D127 may be eliminated.

  The image reading apparatus to which the electro-optical device 10 or 50 can be applied has been described above. However, the electro-optical device 10 or 50 can be applied to other image reading devices, and such an image forming apparatus is the present invention. Within the scope of the invention. For example, the light receiving device may move together with the electro-optical device 10 or 50 as the illumination device, or the light receiving device and the electro-optical device 10 or 50 may be fixed together so that the document or the reading target is moved and read. Also good.

<Other applications>
The electro-optical device according to the present invention can be further applied to various exposure devices, illumination devices, and image display devices.

1 is a cross-sectional view illustrating an electro-optical device according to a first embodiment of the invention. FIG. 2 is a partial plan view of the electro-optical device illustrated in FIG. 1. It is sectional drawing which shows the detail of the OLED element in the said electro-optical apparatus. It is a block diagram which shows the drive system of the said electro-optical apparatus. FIG. 5 is a circuit diagram of each pixel circuit in the drive system of FIG. 4. FIG. 3 is a diagram illustrating a first step in a procedure for manufacturing the electro-optical device illustrated in FIG. 1. It is a figure which shows the next process of FIG. It is a figure which shows the next process of FIG. It is a figure which shows the next process of FIG. FIG. 6 is a cross-sectional view illustrating an electro-optical device according to a second embodiment of the invention. FIG. 11 is a partial plan view of the electro-optical device illustrated in FIG. 10. It is a figure which shows the first process of the procedure which manufactures the electro-optical apparatus shown in FIG. FIG. 13 is a diagram showing a step subsequent to FIG. 12. It is a figure which shows the next process of FIG. It is a figure which shows the next process of FIG. FIG. 16 is a diagram showing a step subsequent to that in FIG. 15. FIG. 11 is a longitudinal sectional view showing an example of an image forming apparatus using the electro-optical device shown in FIG. 1 or 10. FIG. 11 is a longitudinal sectional view showing another example of an image forming apparatus using the electro-optical device shown in FIG. 1 or 10. FIG. 11 is a longitudinal sectional view illustrating an example of an image reading apparatus using the electro-optical device illustrated in FIG. 1 or 10.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10,50 ... Electro-optical apparatus, 12,52 ... Board | substrate, 14 ... OLED element (self-light-emitting element), 20A ... Low-potential power line, 20B ... High-potential power line, 20C ... High-potential power line, 24 ... Sealing body , 28 ... circuit elements, L0 to L127 ... data lines, 280 ... drive circuit, 78 ... second substrate, 10K, 10C, 10M, 10Y, 167, 206 ... organic EL array exposure head (electro-optical device), 110K, 110C, 110M, 110Y, 165 ... photosensitive drum (image carrier), 111,168 ... corona charger, 114 ... developer, 112 ... primary transfer corotron (transfer device), 120,169 ... intermediate transfer belt, 161 ... Developing unit, 163Y, 163C, 163M, 163K ... developer, 166 ... primary transfer roller (transfer device), 203 ... original, 210 ... original reader, 213 ... -Sensor (light-receiving device).

Claims (4)

A substrate,
A plurality of self-luminous elements formed on the substrate;
A sealing body attached to the substrate so as to seal the self-luminous element in cooperation with the substrate;
An electro-optical device provided with a circuit arranged to overlap the sealing body and for driving or controlling the self-luminous element.   The sealing body further includes a second substrate attached to the opposite side of the substrate, and the circuit is provided on the second substrate, and the second substrate includes at least the circuit and 2. The electro-optical device according to claim 1, further comprising a power line for supplying power to one of the self-luminous elements. An image carrier;
A charger for charging the image carrier;
The electro-optical device according to claim 1, wherein a plurality of the self-light-emitting elements are arranged, and a latent image is formed by irradiating light on the charged surface of the image carrier with the plurality of self-light-emitting elements. When,
A developing unit that forms a visible image on the image carrier by attaching toner to the latent image;
An image forming apparatus comprising: a transfer unit that transfers the visible image from the image carrier to another object. The electro-optical device according to claim 1, wherein a plurality of the self-light-emitting elements are arranged;
An image reading apparatus comprising: a light receiving device that converts light emitted from the light-emitting element and reflected by a reading target into an electric signal.

Images