JP2008140632A - Electroluminescent light source unit, image sensor, and image forming device with image sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an EL light source unit, easy to handle, capable of protecting a fragile glass substrate, and capable of eliminating a wasteful space for electric connection. <P>SOLUTION: The EL light source unit 22 is provided with EL elements 24, 25, and a rigid printed wiring board 23. The EL elements 24, 25 are provided with strip glass substrates 36 with a plurality of electrodes 41 formed, respectively, at first end parts 38 and second end parts 39 positioned opposite to the first end parts 38, and light-emitting parts 37 emitting light by organic electroluminescence formed on the glass substrates 36. The printed wiring board 23 retains the glass substrates 36 of the EL elements 24, 25 for the whole length. The electrodes 41 positioned at the first end parts 38 of the EL elements 24, 25 are electrically connected with the printed wiring board 23, and the electrodes 41 positioned at the second end parts 39 of the EL elements 24, 25 are electrically connected with the printed wiring board 23, respectively, through flexible wiring boards 26. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an EL light source unit including an EL light emitting element that emits light by organic electroluminescence, and an image sensor using the EL light source unit as a light source. Furthermore, the present invention relates to an image forming apparatus equipped with an image sensor using an EL light emitting element as a light source.

  For example, a multi-function image forming apparatus called a multifunction peripheral (MFP) having a scanner function, a printing function, a copying function, a network connection function, etc. It is equipped with a line scanning image sensor that optically reads this information.

  This type of image sensor includes a light source that irradiates a reading target with light. As this light source, an LED light emitting element is widely used. However, in recent years, an attempt has been made to use an EL light emitting element as shown in Patent Document 1 instead of the LED light emitting element.

  The EL light emitting element includes a strip-shaped glass substrate extending in the scanning direction and a light emitting portion formed on the surface of the glass substrate. The light emitting part emits light by electroluminescence when an electric field is applied, and extends in a straight line along the longitudinal direction of the glass substrate.

  By the way, in an image sensor using an EL light emitting element as a light source, when a difference in illuminance occurs on the light irradiation surface of the reading object, there arises a problem that the image quality in a portion with low illuminance deteriorates than the image quality in a portion with high illuminance. . For this reason, in an image sensor using an EL light emitting element as a light source, an EL light emitting element having a uniform luminance distribution along the scanning direction is required in order to improve variation in image quality.

  Furthermore, in a multifunctional image forming apparatus in which the A3 size is generally used, the EL light emitting element becomes longer. For this reason, in order to obtain an EL light emitting device having uniform brightness over the entire length, it is necessary to apply a voltage to both ends along the longitudinal direction.

At the same time, the optical axis of the lens that guides the light reflected by the reading object to the light receiving element is generally set so that no shadow is formed on the light irradiation surface of the reading object when the reading object is irradiated with light. Two EL light emitting elements are arranged between the two.
JP 2003-87502 A

  In order to obtain an EL light-emitting element having uniform luminance over the entire length, it is inevitable that a plurality of electrodes are located at both ends of a long glass substrate that is easily damaged. Therefore, when the printed circuit board that controls the EL light-emitting element and the electrode are connected via a plurality of cables, the connection portion between the cable and the electrode is concentrated on the edge of the fragile glass substrate. become.

  Therefore, there is a possibility that an external force such as pulling acts on the end portion of the glass substrate via a plurality of cables, and this is one factor that causes damage to the EL light emitting element.

  Furthermore, since a plurality of cables are drawn from both ends of the glass substrate, a wide space for wiring the cables around the EL light emitting element must be secured. Therefore, the size of the image sensor is increased by this space, which goes against the recent demand for a compact image sensor.

  An object of the present invention is to obtain an EL light source unit that can protect a fragile glass substrate, can be easily handled, and can eliminate useless space for electrical connection.

  Another object of the present invention is to obtain a compact image sensor using the EL light source unit as a light source.

  Still another object of the present invention is to obtain an image forming apparatus equipped with the image sensor.

  In order to achieve the above object, an EL light source unit according to one embodiment of the present invention has a plurality of electrodes formed on a first end and a second end located on the opposite side of the first end, respectively. EL light-emitting element including a strip-shaped glass substrate and a light-emitting portion that emits light by organic electroluminescence formed on the glass substrate, and a rigid printed wiring board that holds the glass substrate of the EL light-emitting element over its entire length And between the electrode positioned at the first end of the EL light emitting element and the printed wiring board, and between the electrode positioned at the second end of the EL light emitting element and the printed wiring board, respectively. And a plurality of flexible wiring boards that are electrically connected.

  In order to achieve the above object, an image sensor according to an aspect of the present invention includes a housing, a light source that is supported by the housing and that emits light toward an object to be read, a light source that is supported by the housing, And a circuit board for controlling driving. The light source includes a strip-shaped glass substrate in which a plurality of electrodes are respectively formed on a first end and a second end located on the opposite side of the first end, and an organic electroluminescence formed on the glass substrate. A pair of EL light-emitting elements including a light-emitting portion that emits light by luminescence, and a rigid printed wiring board that holds the glass substrate of the EL light-emitting element over the entire length thereof. Between the electrode located at the end of the EL and the printed wiring board and between the electrode located at the second end of the EL light emitting element and the printed wiring board via the flexible wiring board, respectively. In addition to being connected, the printed wiring board and the circuit board are electrically connected via a cable.

  In order to achieve the above object, an image forming apparatus according to an aspect of the present invention includes a conveyance path that conveys an object to be read, and an image that is installed in the conveyance path and optically reads image information from the reading object. And a sensor. The image sensor includes: (1) a housing; (2) a light source that is supported by the housing and emits light toward an object to be read; and (3) a circuit board that is supported by the housing and controls the light source. And. The light source includes a strip-shaped glass substrate in which a plurality of electrodes are respectively formed on a first end and a second end located on the opposite side of the first end, and an organic electroluminescence formed on the glass substrate. An EL light-emitting element including a light-emitting portion that emits light by luminescence; and a rigid printed wiring board that holds a glass substrate of the EL light-emitting element over the entire length thereof, and includes a first end of the EL light-emitting element. The electrode located at the portion and the printed wiring board, and the electrode located at the second end of the EL light emitting element and the printed wiring board are electrically connected via a flexible wiring board, respectively. In addition, the printed wiring board and the circuit board are electrically connected via a cable.

  ADVANTAGE OF THE INVENTION According to this invention, the weak EL light emitting element which has a glass substrate can be reinforced and protected with a rigid printed wiring board. At the same time, since the electrical connection between the electrode of the EL light emitting element and the printed wiring board is performed on the printed wiring board, the electrical connection is made to the first and second ends of the fragile glass substrate where the electrode is located. External force accompanying wiring routing becomes difficult to work.

  Therefore, for example, in the production process and transportation process of the EL light emitting element, the EL light emitting element can be easily handled, and a special cushioning material and packaging material for protecting the EL light emitting element can be eliminated.

  Further, since the plurality of electrodes of the EL light emitting element can be connected using a printed wiring board, the number of cables drawn out of the EL light emitting element can be significantly reduced from the number of electrodes. As a result, it is not necessary to secure a space for passing many cables around the EL light emitting element or inside the image sensor housing, and the EL light source unit and thus the image sensor housing can be made compact.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows an outline of the image forming apparatus 1 expanded linearly. The image forming apparatus 1 includes a hopper table 3 on which a document 2 as a reading object is placed. The document 2 placed on the hopper table 3 is sent to the conveyance path 5 via the paper feed roller 4. The conveyance path 5 connects the hopper table 3 and a stacker (not shown).

  A plurality of rollers 6 are arranged on the conveyance path 5. The rollers 6 are arranged at intervals in the feeding direction of the document 2 and are rotated in synchronization with each other. By the rotation of the roller 6, the document 2 is sequentially conveyed from the start end to the end of the conveyance path 5.

  In the middle of the conveyance path 5, for example, a contact image sensor 10 is disposed. The contact image sensor 10 is for optically reading information such as characters and images from the document 2 conveyed along the conveyance path 5, and is installed below the conveyance path 5.

  As shown in FIGS. 2 to 4, the contact image sensor 10 has a housing 11 made of synthetic resin. The housing 11 has an elongated bar shape along the scanning direction, and extends in a direction orthogonal to the conveyance direction of the document 2.

  A first recess 12 is formed on the upper surface of the housing 11. The first recess 12 extends in the longitudinal direction of the housing 11. The first recess 12 has an opening 13 that opens to the upper surface of the housing 10, and a bottom surface 14 that faces the opening 13. The opening 13 is closed by a transparent glass plate 15. The glass plate 15 is exposed to the conveyance path 5, and the document 2 passes through the glass plate 15.

  A second recess 16 is formed on the bottom surface of the housing 11. The second recess 16 extends in the longitudinal direction of the housing 11. The second recess 16 communicates with the first recess 12 through a communication hole 17 formed inside the housing 11. The communication hole 17 is located at the center along the width direction of the housing 11 and extends in the longitudinal direction of the housing 11.

  A lens unit 18 is held inside the communication hole 17. The lens unit 18 extends in the longitudinal direction of the housing 11, and its upper end protrudes into the first recess 12. The lens unit 18 has a central axis O1 that stands up perpendicular to the scanning direction.

  A sensor substrate 19 is attached to the second recess 16. The sensor substrate 19 extends in the longitudinal direction of the housing 11 so as to close the second recess 16. A plurality of light receiving elements 20 such as CCDs are mounted on the upper surface of the sensor substrate 19. The light receiving elements 20 are arranged in a line in the longitudinal direction of the housing 11 and are positioned on the central axis O <b> 1 of the lens unit 18.

  The first recess 12 of the housing 11 houses an organic EL light source unit 22 as shown in FIG. The organic EL light source unit 22 of the present embodiment is provided on a rigid printed wiring board 23, a pair of EL light emitting elements 24, 25 attached to the printed wiring board 23, and both ends of the EL light emitting elements 24, 25. And four flexible wiring boards 26.

  The printed wiring board 23 is made of a hard material that is difficult to bend, such as glass epoxy resin or ceramic. As shown in FIGS. 5 and 6, the printed wiring board 23 has a pair of EL support portions 27a and 27b. The EL support portions 27a and 27b extend in a line shape in the longitudinal direction of the housing 11 along the scanning direction. The EL support portions 27a and 27b have one end 28 and the other end 29, respectively. The one end 28 and the other end 29 are separated from each other in the longitudinal direction of the EL support portions 27a and 27b.

  One end 28 of one EL support portion 27 a and one end 28 of the other EL support portion 27 b are connected to each other via a bridge portion 30. Similarly, the other end 29 of one EL support portion 27 a and the other end 29 of the other EL support portion 27 b are connected to each other via another bridge portion 31. For this reason, the EL support portions 27a and 27b of the printed wiring board 23 are arranged in parallel with a space between each other.

  As shown in FIGS. 4 and 8, each of the EL support portions 27 a and 27 b of the printed wiring print 23 includes a first surface 32 and a second surface 33 located on the opposite side of the first surface 32. have. The first surface 32 faces the direction of the glass plate 15. A pair of first electrodes 34 is formed on the first surface 32 at positions corresponding to the one end 28 and the other end 29 of the EL support portions 27a and 27b. As shown in FIG. 6, the first electrodes 34 are aligned in the width direction of the EL support portions 27a and 27b and are separated in the longitudinal direction of the EL support portions 27a and 27b. For this reason, the EL support portions 27a and 27b have four first electrodes 34, respectively.

  As shown in FIG. 4, the second surfaces 33 of the EL support portions 27 a and 27 b of the printed wiring board 23 face the direction of the bottom surface 14 of the first recess 12 of the housing 11. A pair of second electrodes 35 (only one is shown) is formed on the second surface 33 of one EL support portion 27a. The second electrode 35 is located at one end 28 of the EL support portion 27 a and is electrically connected to the first electrode 34 through a conductor layer (not shown) formed on the printed wiring board 23.

  The EL light emitting elements 24 and 25 are mounted on the first surfaces 32 of the EL support portions 27a and 27b. Each of the EL light emitting elements 24 and 25 includes a transparent glass substrate 36 and a light emitting unit 37. The glass substrate 36 extends in a line shape along the scanning direction. The glass substrate 36 has a first end 38 and a second end 39. The first end portion 38 is located at one end along the longitudinal direction of the glass substrate 36. The second end 39 is located at the other end along the longitudinal direction of the glass substrate 36, which is the opposite side of the first end 38.

  A pair of third electrodes 41 is formed on the first and second end portions 38 and 39 of the glass substrate 36, respectively. The third electrode 41 is an ITO (Indium Tin Oxide) electrode made of an oxide film of indium and tin, for example, and is arranged in the width direction of the glass substrate 36 as shown in FIG.

  The light emitting unit 37 is formed on the lower surface of the glass substrate 36 and extends in the longitudinal direction of the glass substrate 36. The light emitting unit 37 emits light by electroluminescence when an electric field is applied, and one end and the other end along the longitudinal direction are electrically connected to the third electrode 41. For this reason, the light emitting portion 37 is configured to emit light uniformly in the longitudinal direction when an electric field is applied by applying a voltage to both ends along the longitudinal direction. In other words, the luminance distribution of the EL light emitting elements 24 and 25 is uniform along the longitudinal direction.

  The glass substrates 36 of the EL light emitting elements 24 and 25 are bonded to the first surfaces 32 of the EL support portions 27a and 27b of the printed wiring board 23 by, for example, a double-sided adhesive tape 42. Therefore, the EL support portions 27a and 27b hold the glass substrate 36 of the EL light emitting elements 24 and 25 over the entire length.

  The flexible wiring boards 26 positioned on both sides of the EL light emitting elements 24 and 25 are for electrically connecting the EL light emitting elements 24 and 25 and the printed wiring board 23. Each flexible wiring board 26 has a flexible insulating film 43 such as polyester or polyimide. A fourth electrode 44 and a fifth electrode 45 are formed on the insulating film 43.

  The fourth electrode 44 corresponds to the first electrode 34 of the printed wiring board 23 and is located at one end of the insulating film 43. The fifth electrode 44 corresponds to the third electrode 41 of the glass substrate 36 and is located at the other end of the insulating film 43.

  The fourth electrode 44 of the flexible wiring board 26 and the first electrode 34 of the printed wiring board 23 are thermocompression bonded with an anisotropic conductive film 46 interposed therebetween. Similarly, the fifth electrode 45 of the flexible wiring board 26 and the third electrode 41 of the glass substrate 36 are thermocompression bonded with another anisotropic conductive film 47 interposed therebetween.

  Therefore, the flexible wiring board 26 is formed between the first electrode 34 and the fourth electrode 44 and between the third electrode 41 and the fifth electrode 45 on the first surface 32 of the printed wiring board 23. They are electrically connected.

  As shown in FIGS. 3, 4, and 7, a metal plate 48 is laminated on the second surface 33 of the EL support portions 27a and 27b. The metal plate 48 has a length dimension that extends over the entire length of the light emitting portion 37 of the EL light emitting elements 24, 25, and the width dimension is constant over the entire length. An insulating tape 50 is interposed between the second surface 33 and the metal plate 48. The second electrode 35 located on the second surface 33 is exposed to the inside of the first recess 12 without being covered with the metal plate 48 or the insulating tape 50.

  As shown in FIGS. 3 and 4, the metal plate 48 is fixed to the bottom surface 14 of the first recess 12 via a double-sided adhesive tape 51. In a state where the EL light emitting elements 24 and 25 are fixed to the first recess 12, the EL light emitting elements 24 and 25 are arranged in two rows with the lens unit 18 interposed therebetween.

  As shown in FIGS. 3 and 9, a circuit board 53 that controls driving of the EL light emitting elements 24 and 25 is supported on the housing 11. The circuit board 53 has a rectangular shape extending in the longitudinal direction of the housing 11, and a plurality of locations along the longitudinal direction are fixed to boss portions 54 protruding from the side surfaces of the housing 11 via rivets 55. Further, the circuit board 53 is laminated on the lower surface of the sensor substrate 19 and is electrically connected to the sensor substrate 19.

  As shown in FIG. 9, the circuit board 53 is electrically connected to the printed wiring board 23 of the organic EL light source unit 22 via two cables 56. The cable 56 is wired through a cable passage 57 formed in the housing 11 and a through hole 58 opened in the sensor substrate 19.

  As shown in FIG. 4, one end of the cable 56 is guided from the cable passage 57 between the printed wiring board 23 and the bottom surface 14 of the first recess 12 and is soldered to the second electrode 35 of the printed wiring board 23. It is attached.

  Further, the cable 56 is drawn out of the housing 11 from the cable passage 57 through the through hole 58. The other end of the cable 58 is routed along the lower surface of the circuit board 53 and then soldered to a pair of pads 59 formed on the lower surface of the circuit board 53.

  When the organic EL light source unit 22 configured as described above is operated, the light emitting portions 37 of the EL light emitting elements 24 and 25 emit light. Light from the light emitting unit 37 is applied to the document 2 through the glass plate 15. The light irradiated on the document 2 is reflected by the lower surface of the document 2 and then guided to the light receiving element 20 through the lens unit 18. The light receiving element 20 outputs a signal having a level corresponding to the amount of received light. Thereby, information such as characters and images drawn on the document 2 is optically read.

  According to such a contact image sensor 10, the fragile glass substrate 36 constituting the EL light emitting elements 24 and 25 is bonded to the first surfaces 32 of the EL support portions 27 a and 27 b of the printed wiring board 23. The printed wiring board 23 is made of a hard material that is difficult to bend, and the EL support portions 27a and 27b hold the glass substrate 36 over its entire length.

  For this reason, the glass substrate 36 that is easily damaged among the EL light emitting elements 24 and 25 can be reinforced by the rigid printed wiring board 23, and the EL light emitting elements 24 and 25 can be protected from external vibration and impact. it can.

  In particular, in the present embodiment, since the metal plate 48 is laminated on the EL support portions 27 a and 27 b of the printed wiring board 23, the glass substrate 36 can be protected by both the metal plate 48 and the printed wiring board 23. .

  Furthermore, the flexible wiring board 26 that electrically connects the third electrode 41 of the EL light emitting elements 24 and 25 and the first electrode 34 of the printed wiring board 23 is formed on the printed wiring board 23 with the third electrode 41. It straddles between the electrode 41 and the first electrode 34.

  For this reason, electrical connection between the EL light emitting elements 24 and 25 and the printed wiring board 23 is performed on the hard printed wiring board 23. For example, the third electrodes of the EL light emitting elements 24 and 25 are provided. In comparison with the case where the lead wires are individually soldered to 41, it is difficult to apply an external force due to the lead wires to the first and second end portions 38, 39 of the fragile glass substrate 36.

  As a result, for example, in the production process and transportation process of the EL light-emitting elements 24, 25, the EL light-emitting elements 24, 25 can be easily handled, and a special cushioning material or packaging that protects the EL light-emitting elements 24, 25 from impact. The material can be made unnecessary.

  In addition, a total of eight first electrodes 34 included in the EL light emitting elements 24 and 25 are connected to the printed wiring board 23, so that the eight first electrodes 34 are connected to the pair of third electrodes of the printed wiring board 23. The electrodes 41 can be consolidated. For this reason, the number of cables 56 drawn out of the EL light source unit 22 can be reduced to two, and it is not necessary to secure a wide space for wiring around the EL light source unit 22 or inside the housing 11.

  Therefore, the EL light source unit 22 and the housing 11 can be formed in a compact manner, and there is an advantage that it contributes to downsizing of the contact image sensor 10 and thus the image forming apparatus 1.

  In the above embodiment, the glass substrate of the EL light emitting element is bonded to the EL support portion of the printed wiring board via the double-sided adhesive tape, but the present invention is not limited to this. For example, you may make it hold | maintain a glass substrate in an EL support part using the holder engaged so that it may straddle between a glass substrate and an EL support part.

1 is a side view schematically showing an image forming apparatus according to an embodiment of the present invention. 1 is a perspective view of a contact image sensor according to an embodiment of the present invention. Sectional drawing which follows the width direction of the contact type image sensor which concerns on embodiment of this invention. Sectional drawing which follows the longitudinal direction of the contact | adherence image sensor which concerns on embodiment of this invention. The top view of the organic electroluminescent light source unit which concerns on embodiment of this invention. The top view which shows the structure of the connection part of a printed wiring board and EL light emitting element in embodiment of this invention. Sectional drawing of the organic electroluminescent light source unit which concerns on embodiment of this invention. Sectional drawing of the organic electroluminescent light source unit which shows the structure of the connection part of EL light emitting element and a printed wiring board in embodiment of this invention. 1 is a perspective view of a contact image sensor showing a structure of a connection portion between a circuit board and a cable supported by a housing in an embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 2 ... Reading object (original), 5 ... Conveyance path, 10 ... Image sensor (contact type image sensor), 11 ... Housing, 22 ... Light source (EL light source unit), 23 ... Printed wiring board, 24, 25 ... EL light emission Elements 26, flexible wiring board, 28, one end, 29, the other end, 36, glass substrate, 37, light emitting section, 38, first end, 39, second end, 41, electrode (third Electrode), 53 ... circuit board, 56 ... cable.

Claims (10)

A band-shaped glass substrate in which a plurality of electrodes are formed on each of the first end and the second end located on the opposite side of the first end, and light emission by organic electroluminescence formed on the glass substrate An EL light-emitting element including a light-emitting unit that
A rigid printed wiring board for holding the glass substrate of the EL light emitting element over its entire length;
Electrical connection between the electrode located at the first end of the EL light emitting element and the printed wiring board, and between the electrode located at the second end of the EL light emitting element and the printed wiring board, respectively. A plurality of flexible wiring boards connected to the EL light source unit.   2. The EL light source unit according to claim 1, wherein the electrode of the EL light emitting element and the flexible wiring board are thermocompression bonded to each other with an anisotropic conductive film interposed therebetween.   2. The EL light source unit according to claim 1, wherein the glass substrate is bonded to the printed wiring board.   2. The printed wiring board according to claim 1, wherein the printed wiring board has a first surface on which the EL light emitting element is mounted, and a second surface located on the opposite side of the first surface. A metal plate is laminated on the surface of the EL light source unit. Rigid printed wiring board,
An EL light source unit comprising a pair of EL light emitting elements mounted on the printed wiring board,
Each of the EL light-emitting elements is formed on the glass substrate and a strip-shaped glass substrate in which a plurality of electrodes are formed on a first end and a second end located on the opposite side of the first end, respectively. A light emitting portion that emits light by organic electroluminescence, and the glass substrate of the EL light emitting element is held by the printed wiring board over the entire length,
Flexible wiring between the electrode positioned at the first end of the EL light emitting element and the printed wiring board, and between the electrode positioned at the second end of the EL light emitting element and the printed wiring board, respectively. An EL light source unit which is electrically connected through a plate.   6. The EL light source unit according to claim 5, wherein the EL light emitting elements are arranged in parallel with a space therebetween. A housing;
A light source that is supported by the housing and emits light toward the reading object;
An image sensor comprising a circuit board supported by the housing and governing driving of the light source,
The light source is
A band-shaped glass substrate in which a plurality of electrodes are respectively formed on a first end and a second end located on the opposite side of the first end, and light emission by organic electroluminescence formed on the glass substrate A pair of EL light-emitting elements including a light-emitting unit that
A rigid printed wiring board that holds the glass substrate of the EL light emitting element over its entire length,
Flexible wiring between the electrode positioned at the first end of the EL light emitting element and the printed wiring board, and between the electrode positioned at the second end of the EL light emitting element and the printed wiring board, respectively. Electrically connected through the board,
An image sensor, wherein the printed wiring board and the circuit board are electrically connected via a cable.   8. The image sensor according to claim 7, wherein the housing has a cable passage through which the cable passes.   8. The printed wiring board according to claim 7, wherein the printed wiring board includes a first surface that holds the glass substrate of the EL light emitting element over its entire length, and a second surface that is located on the opposite side of the first surface. An image sensor comprising: a metal plate laminated on the second surface. A conveyance path for conveying an object to be read; and
An image sensor that is installed in the conveyance path and optically reads image information from the reading object,
The above image sensor
(1) a housing;
(2) A light source that is supported by the housing and irradiates light toward the reading object;
(3) a circuit board that is supported by the housing and controls the driving of the light source,
The light source is
A band-shaped glass substrate in which a plurality of electrodes are respectively formed on a first end and a second end located on the opposite side of the first end, and light emission by organic electroluminescence formed on the glass substrate An EL light-emitting element including a light-emitting unit that
A rigid printed wiring board that holds the glass substrate of the EL light emitting element over its entire length,
Flexible wiring between the electrode positioned at the first end of the EL light emitting element and the printed wiring board, and between the electrode positioned at the second end of the EL light emitting element and the printed wiring board, respectively. Electrically connected through the board,
An image forming apparatus, wherein the printed wiring board and the circuit board are electrically connected via a cable.

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