JP5347764B2 - Light emitting substrate device, print head, and image forming apparatus - Google Patents

Description

  The present invention relates to a light-emitting substrate device having a plurality of light-emitting element arrays mounted on the surface thereof, a print head including the light-emitting substrate device, and an image forming apparatus such as a digital copying machine including the print head.

  Conventionally, in order to form an electrostatic latent image of an image on the surface of a photoreceptor of an image forming apparatus, a print head including a light emitting element array and a lens array as main components has been used (for example, Patent Document 1). To 4).

  The light emitting element array is a linear array of a plurality of light emitting elements such as light emitting diodes (LEDs) (for example, 128), a driving element that outputs a signal for driving the light emitting element array, an image processing element, and the like. Any light emitting element can be turned on (turned on) / off (turned off) by a signal from the electronic component.

  The light emitting element array and the electronic component such as the drive element are generally mounted close to each other because the light emitting element cannot normally be turned on / off when noise is applied to the signal output from the electronic component. It has been broken.

  As a configuration in which an electronic component such as a driving element and a light emitting element array are brought close to each other, there is a configuration in which a light emitting element array is mounted on the surface of one printed wiring board and an electronic component such as a driving element is mounted on the back surface.

JP 2006-289843 A JP 2005-193638 A JP 2000-141744 A Japanese Patent Laid-Open No. 11-266037

  However, with such a configuration, electronic components such as driving elements generate heat, so this heat is directly transmitted to the printed wiring board and the light emitting element array, warping the printed wiring board, bending the optical axis of the light emitting element array, and the light emitting element. Cause problems such as a decrease in the amount of light.

  Accordingly, a first printed wiring board on which a plurality of light emitting element arrays are mounted, a driving element that outputs a signal for driving the light emitting element array, and a second printed wiring board on which electronic components such as image processing elements are mounted. 2. Description of the Related Art A light-emitting board device that employs means in which two printed wiring boards are prepared and both printed wiring boards are opposed to each other and connected by a connecting member such as a connector is used.

  The light emitting board device having such a configuration does not directly transfer the heat generated by the electronic component to the first printed wiring board and the light emitting element array, and standardizes the first printed wiring board or the second printed wiring board. There is a cost merit that it can be done.

  However, as described above, since the electronic components such as the drive elements and the light emitting element array need to be provided close to each other, the second printed wiring board cannot be separated from the first printed wiring board. For this reason, heat generated from electronic components such as drive elements mounted on the second printed wiring board is transmitted through the air between the first printed wiring board and the second printed wiring board, and the first printed circuit board There is a problem of locally heating a portion (area) corresponding to an electronic component such as a drive element in the wiring board.

  Here, a portion (area) corresponding to an electronic component such as a driving element in the first printed wiring board is a perspective of the first printed wiring board when viewed through the back surface of the second printed wiring board. A portion (area) occupied by electronic components such as drive elements on the back surface. For example, both are fixed with a connecting member so that the back surface of the first printed wiring board and the front surface of the second printed wiring board face each other (facing each other), and electronic components are mounted on the front surface of the second printed wiring board In this case, the portion corresponding to the electronic component such as the driving element in the first printed wiring board is a portion facing the electronic component on the back surface of the first printed wiring board.

  When the above-described problem occurs, the first printed wiring board is long, so that when it is locally heated, warping occurs, and the optical axes of the light emitted from all the light emitting elements do not become parallel. Then, when this light emitting board device is used for a print head, there arises a problem that an imaging line formed by light emitted from the light emitting element array mounted on the surface of the first printed wiring board is bent. Here, the imaging line refers to a line formed by connecting a plurality of focal points (imaging points) where light emitted from a plurality of light emitting elements of the light emitting element array converges through the lens array.

  Further, when the first printed wiring board is locally heated by the heat generated by the driving element, the light emitting element array mounted on the surface area of the first printed wiring board corresponding to the heated area. There is also a problem that heat is transmitted and the light amount of the light emitting element array is reduced.

  The present invention has been made to solve the above-described problem, and is opposed to the electronic component of the second printed wiring board on the back surface of the first printed wiring board on which a plurality of light emitting element arrays are mounted on the surface. An object of the present invention is to provide a light-emitting board device and the like that have a simple configuration in which a dummy pattern is formed in an area where the first printed wiring board is not affected by heat generated by electronic components.

(First invention)
The light-emitting board device according to the first aspect of the present invention is a long first printed wiring board having a plurality of light-emitting element arrays mounted linearly or in a staggered pattern on the surface along the longitudinal direction, and light-emitting elements on the front and / or back surfaces The second printed wiring board on which electronic components that output signals for driving the array are mounted, and the back surface of the first printed wiring board and the front surface of the second printed wiring board are opposed to each other. A connection member for connecting the printed wiring board and the second printed wiring board is provided.

  When viewed through the back surface of the second printed wiring board, a dummy pattern is formed in the area occupied by the electronic component on the back surface of the first printed wiring board.

  Here, the dummy pattern refers to a conductive pattern of a pattern or a pattern additionally formed on the bare board, which is not intended for electrical connection (connection) between electronic components such as a wiring pattern. That is, with regard to the light emitting substrate device, it is a conductor pattern that does not directly participate in the ON / OFF operation of the light emitting element in the light emitting element array. The dummy pattern is preferably formed of the same material (copper foil or the like) as the wiring pattern in order to reduce the manufacturing cost.

  An electronic component that outputs a signal for driving the light emitting element array is a driving element that directly outputs a driving signal to the light emitting element array, an image processing element that outputs an image processing signal to the driving element, or the like. An integrated circuit (IC) is an electronic component that generates heat when driven.

  With the above-described configuration, heat generated by the operation of the electronic component that outputs a signal for driving the light emitting element array can be radiated by the dummy pattern. For this reason, the first printed wiring board is warped, the light amount of the light emitting element array mounted on the surface of the first printed wiring board is decreased, the optical axes of all the light emitting element arrays are not parallel, etc. There is no problem.

(Second invention)
In the light emitting substrate device of the second invention, the dummy pattern is connected to the ground.

  Here, the ground means a ground pattern formed on the front surface and / or the back surface in the case of a two-layer substrate in which a conductor pattern is formed on the front surface and the back surface of the printed wiring board. In the case of a multilayer printed wiring board on which is formed, it means a ground layer formed in the intermediate layer.

  With the configuration described above, not only the effect of the first invention described above can be achieved, but also the heat of the electronic component transmitted to the dummy pattern can be efficiently radiated from the ground. In addition, noise from the outside can be dropped to the ground and removed by the dummy pattern.

(Third invention)
In the light-emitting board device of the third invention, in the first invention or the second invention, the length of the first printed wiring board in the longitudinal direction is the length of the first printed wiring board in the longitudinal direction of the second printed wiring board. The dummy pattern is formed beyond the area facing the second printed wiring board in the first printed wiring board.

  With this configuration, since the dummy pattern is long, it is possible to obtain a heat dissipation effect that is greater than that described in the first or second invention. In addition, the heat of the remaining electronic components that cannot be dissipated can be transmitted to the first printed wiring board over a wide range, so that the light emitting element array mounted on the surface of the first printed wiring board Effects such as a decrease in the amount of light and the fact that the optical axes of all the light emitting element arrays are not parallel can be further reduced.

(Fourth invention)
The print head of the fourth invention is fixed to the housing such that a lens array in which a plurality of rod lenses are aligned, a housing to which the lens array is fixed, and one lens surface of the lens array and the light emitting element array face each other. The light-emitting substrate device according to any one of the first to third inventions is provided.

  With this configuration, a print head free from defects such as bending of the imaging line created by the imaging point of the light emitted from all the light emitting elements due to the heat generated by the electronic components, or a reduction in the light amount of the light emitting elements is provided. it can.

(Fifth invention)
An image forming apparatus according to a fifth aspect of the invention comprises a photoconductor for forming an electrostatic latent image on the surface thereof, and a print head according to the fourth aspect of the invention fixed opposite to the photoconductor.

  With this configuration, an image forming apparatus capable of forming a high-quality image because there are no problems such as bending of an image forming line formed by connecting the image forming points of the print head due to the heat of the electronic component or a reduction in the light amount of the light emitting element. Can provide.

  According to the present invention, it is possible to provide a light emitting substrate device that does not affect the operation of the light emitting element array due to the heat generated by the electronic component. Further, a print head using this light emitting substrate device can make the imaging line straight without being affected by the heat generated by the electronic component. For this reason, an image forming apparatus using this print head can form a high-quality image.

(Example 1) which is a top view of a light-emitting substrate device. 1 is a front view of a light emitting substrate device (Example 1). (Example 1) which is a rear view of a light-emitting substrate device. 1 is a rear view of a first printed wiring board (Example 1). FIG. (Example 1) which is the elements on larger scale of the back surface of the 1st printed wiring board. (Example 1) which is the perspective view to which a part of surface of the 1st printed wiring board was expanded. (Example 2) which is a front view of a light-emitting substrate device. (Example 2) which is a rear view of a light-emitting substrate device. (Example 2) which is a rear view of the 1st printed wiring board. (Example 3) which is a front view of a light-emitting substrate device. (Example 4) which is the elements on larger scale of the back surface of a 1st printed wiring board. (Example 5) which is a front view of a light-emitting substrate device. (Example 5) which is the elements on larger scale of the back surface of a 1st printed wiring board. (Example 6) which is a top view of a print head. (Example 6) which is a perspective view of a print head. FIG. 6 is a cross-sectional view of a print head (Example 6). (Example 7) which was the figure which showed the use condition of the print head. FIG. 10 is a diagram illustrating a configuration of an image forming apparatus (Example 7).

Hereinafter, the present invention will be described in detail using examples.
In the drawings used in each embodiment, the wiring pattern and the dummy pattern are shown thick, but this is for easy understanding of the description, and actually has a width of several hundred to several tens of microns.

A first embodiment according to the present invention will be described with reference to FIGS.
(Overall configuration of light-emitting substrate device)
As shown in FIGS. 1 to 3, the light-emitting board device 5 according to the present invention is a long first printed wiring board in which a plurality of light-emitting element arrays 4 are mounted on the surface 10 in a zigzag manner along the longitudinal direction. 24, the second printed wiring board 25 on which the electronic component 9 that outputs a signal for driving the light emitting element array 4 is mounted on the front surface 31, the back surface 11 of the first printed wiring board 24, and the second printed circuit board. The first printed wiring board 24 and the connection member 28 for connecting the second printed wiring board 25 are provided so that the front surface 31 of the wiring board 25 faces.

(Second printed wiring board)
First, the second printed wiring board 25 will be described in detail.
As shown in FIG. 2, an application specific integrated circuit (ASIC) as an electronic component 9 is mounted (soldered) on the surface 31 of the second printed wiring board 25. This ASIC is for outputting a signal for driving the light emitting element array 4, and a driving element of the light emitting element array 4 and a controller of an image forming apparatus (not shown) (for example, the image processing unit 140 in FIG. 18). An image processing element that transmits an image processing signal obtained by processing image data sent from the image processing device to the driving element.

  A male connector 27 for connecting to a female connector 26 of the first printed wiring board 24 described later is mounted on the surface 31 of the second printed wiring board 25. The female connector 26 and the male connector 27 constitute a connection member 28. In addition, a female connector 30 for electrical connection with a controller (for example, the image processing unit 140 in FIG. 18) of an image forming apparatus (not shown) is mounted on the back surface 32 of the second printed wiring board 25.

(First printed wiring board)
Next, the first printed wiring board 24 will be described in detail with reference to FIGS. 1 and 6. In addition, description of parts other than the one end part W (FIG. 6) in FIG. 1 is a repetition of substantially the same configuration in which the light emitting element array 4 is continuously fixed in a staggered manner from the one end part W to the other end. Therefore, it is omitted.

  As shown in FIG. 6, the first printed wiring board 24 has a solid pattern 8 made of copper foil having a predetermined width on the surface 10 formed along the longitudinal direction (Y direction), and on the surface of the solid pattern 8, A plurality of light emitting element arrays 4 are fixed in a zigzag manner using an adhesive.

  A plurality of light emitting elements (for example, LEDs) (not shown) are linearly formed on the surface of the light emitting element array 4, and a plurality of pads 13 are also formed. The plurality of pads 13 and the plurality of pads 14 formed on the surface 10 of the first printed wiring board 24 are connected by wires 12. In FIG. 6, only one pad 13 and 14 is shown for simplicity of explanation, but there are actually a plurality of pads.

The pad 14 is electrically connected to a through hole (not shown) formed at a predetermined position of the first printed wiring board 24 by a wiring pattern 15 made of copper foil, and the back surface is formed by the through hole. 11 wiring patterns 16 are electrically connected.
The female connector 26 is mounted on the back surface 11 of the first printed wiring board 24 as described above, and the female connector 26 is connected to the wiring pattern 16 on the back surface 11 described above.

  For this reason, by inserting the male connector 27 of the second printed wiring board 25 into the female connector 26 of the first printed wiring board 24, all the light emitting element arrays 4 and the electronic components 9 are electrically connected. Can do.

  The light emitting board device 5 in which the first printed wiring board 24 and the second printed wiring board 25 having such a configuration are connected by the connecting member 28 is driven by the electronic component 9 for turning on / off the light emitting element array 4. The electronic component 9 generates heat. The heat generated from the electronic component 9 is transmitted to the area 29 facing the front surface of the electronic component 9 on the back surface 11 of the first printed wiring board 24 through the air, and heats the area 29.

  The area 29 is a portion of the back surface 11 surrounded by a dotted line in FIGS. 3 and 4. In other words, as shown in FIGS. 2 to 4, the second area 29 extends from the back surface 32 of the second printed wiring board 25. This is a portion occupied by the electronic component 9 on the back surface 11 of the first printed wiring board 24 when the printed wiring board 25 is seen through.

  The light emitting substrate device 5 according to the present invention is characterized in that a dummy pattern 21 for radiating heat in the area 29 is provided as shown in FIG. Since the dummy pattern 21 is formed of the same base material (copper foil or the like) as the wiring pattern 16 formed on the back surface 11 of the first printed wiring board 24, the thermal pattern is high and the heat dissipation effect is high.

  For this reason, the heat generated from the electronic component 9 is parallel to the longitudinal direction (Y direction) of the first printed wiring board 24 in the area 29, and the short direction (X direction) of the first printed wiring board 24. ) Can be efficiently radiated by the plurality of dummy patterns 21 formed at equal intervals, so that the ON / OFF operation of the light emitting element array 4 is not affected by the heat generated from the electronic component 9.

  That is, due to heat generated from the electronic component 9, the first printed wiring board 24 is warped, the imaging line formed by the light emitted from the light emitting element array 4 is bent, or the light amount of the light emitting element array 4 is decreased. No problems occur.

  In the first embodiment, as shown in FIG. 6, the width dimension C in the X direction of each of the nine dummy patterns 21 formed on the back surface 11 of the first printed wiring board 24 is the wiring pattern 16. It was set to 150 microns, which is the same as the width dimension A in the X direction. Further, the distance D in the X direction between the dummy patterns 21 is set to 100 microns, which is the same as the distance B in the X direction between the wiring patterns 16. In this way, the dummy pattern 21 is formed in parallel with the wiring pattern 16 formed in the longitudinal direction (Y direction) of the first printed wiring board 24 to prevent the first printed wiring board 24 from warping. Desirable in terms.

  1 and 6 show the light emitting element array 4 fixed in a zigzag pattern, it may be fixed in a straight line, and even in this case, the above-described effects can be obtained. Can do.

A second embodiment according to the present invention will be described with reference to FIGS.
For easy understanding, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The main difference between the second embodiment and the first embodiment is that the electronic component 9 is provided on the back surface 32 of the second printed wiring board 33 as shown in FIGS. Reference numeral 34 denotes a connector for electrical connection with a controller (for example, the image processing unit 140 in FIG. 18) of an image forming apparatus (not shown).

  Also in this case, the heat generated from the electronic component 9 is transmitted to the front surface 31 of the second printed wiring board 33 and is transmitted from the front surface 31 to the area 29 on the back surface 11 of the first printed wiring board 24 through the air. . For this reason, as shown in FIG. 5 of the first embodiment, the same effect as that of the first embodiment can be obtained by providing the dummy pattern 21 in the area 29 to dissipate heat.

A third embodiment according to the present invention will be described with reference to FIG.
In order to make the description easy to understand, the same parts as those in the second embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The main difference between the third embodiment and the second embodiment is that, as shown in FIG. 10, in addition to the electronic component 35 mounted on the back surface 32 of the second printed wiring board 33, the electronic component 36 is also provided on the front surface 31. Is implemented. For example, in the case where the electronic component 35 is a drive element of the light emitting element array 4 and the electronic component 36 is an image processing element that processes image data transmitted from a controller (image processing unit) of the image forming apparatus via the connector 34, There can be the configuration of the third embodiment.

  Even in such a configuration, since both the electronic components 35 and 36 generate heat, when viewed through the back surface 32 of the second printed wiring board 33, both of the electronic components 35 and 36 on the back surface 11 of the first printed wiring board 24 are used. By providing the dummy pattern 21 shown in FIG. 5 in the portion occupied by the electronic components 35 and 36, that is, the area 29, the same effect as in the second embodiment can be obtained.

  A fourth embodiment according to the present invention will be described with reference to FIG. For easy understanding, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The main difference between the fourth embodiment and the first embodiment is that through holes 22 are formed at both ends of the dummy pattern 21 formed in the area 29 on the back surface 11 of the first printed wiring board 24 as shown in FIG. The dummy pattern 21 is connected to the ground (not shown) through the through hole 22.

  The ground may be a ground layer formed in an intermediate layer of the first printed wiring board 24 or a ground pattern formed on the surface 10. In any case, since the heat transmitted to the dummy pattern 21 can be radiated from the ground, the heat radiation effect of the first embodiment or more can be obtained.

  In FIG. 11, the through holes 22 are formed at both ends of all the dummy patterns 21. However, the present invention is not limited to this, and only one end may be used. Alternatively, a dummy pattern in the X direction that connects all the dummy patterns 22 may be formed, and the dummy pattern and the ground may be connected by one through hole. Furthermore, when a ground (ground pattern) is formed on the back surface 11, the dummy pattern may be extended to the ground pattern and the dummy pattern and the ground may be connected.

  A fifth embodiment according to the present invention will be described with reference to FIG. For easy understanding, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The main difference between the fifth embodiment and the first embodiment is that a dummy pattern 38 formed on the back surface 11 of the first printed wiring board 24 is extended to the outside of the area 29 as shown in FIG. is there.

  With this configuration, the heat transmitted to the dummy pattern 38 can be dissipated beyond the space surrounded by the first printed wiring board 24 and the second printed wiring board 25, so that the heat radiation effect of the first embodiment or more can be achieved. Can be obtained.

  As shown in FIG. 12, the dummy pattern 38 is substantially the entire area of the first printed wiring board 24 (at least the first (left end) light emitting element array 4 from one end (left end) to the nth (right end). It is desirable to extend to the other end (right end) of the light emitting element array 4. That is, the dummy pattern 38 is preferably formed so as to cover the area of the back surface 11 corresponding to the area of the front surface 10 on which all the light emitting element arrays 4 are mounted.

  With this configuration, not only the heat of the electronic component 9 can be radiated from substantially the entire first printed wiring board 24, but also the first printed wiring board 24 can be warmed substantially uniformly (more localized). Therefore, the influence of the heat generation of the electronic component 4 on the first printed wiring board 24 can be minimized.

  12, it goes without saying that the dummy pattern 38 is provided avoiding (bypassing) the female connector 26 and bypass capacitor (not shown) mounted on the back surface 11 of the first printed wiring board 24.

A sixth embodiment according to the present invention will be described with reference to FIGS.
(Print head)
As shown in FIGS. 14 to 16, a print head 1 according to the present invention includes a housing 2 in which a lens array 3 in which a plurality of rod lenses 6 are arranged and fixed is fixed with an adhesive, and one lens surface of the lens array 3. And the light emitting substrate device 5 fixed to the housing 2 with an adhesive or the like so that the light emitting element array 4 faces each other.

  As shown in FIG. 16, the print head 1 emits light from the light emitting elements when the light emitting elements (such as LEDs) of the light emitting element array 4 mounted (fixed) on the surface 10 of the light emitting substrate device 5 emit light. The distance to the image forming point (focal position) where the reflected light is converged (condensed) by the lens array 3 is set to the conjugate length TC.

  This conjugate length TC is a distance L from the light emitting surface of the light emitting element to the lower surface (one lens surface) of the lens array 3, a distance L from the upper surface (the other lens surface) of the lens array 4 to the image point, This is the sum of the height T of the lens array 4 and the relationship TC = T + 2L is established.

  Further, since the light emitting substrate device 5 has the above-described effects, the print head 1 according to the present invention does not warp even when the temperature change due to the ON / OFF operation of the light emitting element array 4 is repeated (high flatness can be maintained). Therefore, there is little variation in image forming points, and the image forming lines can be made straight.

  A seventh embodiment according to the present invention will be described with reference to FIGS. FIG. 17 is a partially enlarged view of FIG. 18 enlarged for easy understanding of the positional relationship between the print head 1 and the photosensitive drum 17.

(Image forming device)
As shown in FIG. 18, the image forming apparatus according to the present invention is a so-called tandem digital color printer 131, and an image forming process unit 110 that forms an image corresponding to image data of each color, and an image forming process unit 110. And an image processing unit 140 that performs predetermined image processing on the image data received from the personal computer 102 or the image reading apparatus 103.

  The image forming process unit 110 includes four image forming units 111Y, 111M, 111C, and 111K that are arranged in parallel at a predetermined interval.

  Each of the image forming units 111Y, 111M, 111C, and 111K forms an electrostatic latent image and carries a photosensitive drum 17 as an image carrier that carries a toner image, and the surface of the photosensitive drum 17. Obtained by a charging device 113 that is uniformly charged at a predetermined potential, an LED print head 1 as a print head as an exposure device that exposes the photosensitive drum 17 whose surface is charged by the charging device 113, and the LED print head 1. A developing device 115 for developing the electrostatic latent image, and a cleaner (blade) 116 for cleaning the surface of the photosensitive drum 17 after transfer.

  Further, a density detection circuit 117 that detects the toner image density of a test patch (density sample) formed on the photosensitive drum 17 is provided in the vicinity of the downstream side of the developing device 115 so as to face the photosensitive drum 17. It has been. The density detection circuit 117 is connected to the control unit 130 and outputs a toner image density detection value.

  Here, the image forming units 111Y, 111M, 111C, and 111K are configured in substantially the same manner except for the toner stored in the developing device 115. The image forming units 111Y, 111M, 111C, and 111K form yellow (Y), magenta (M), cyan (C), and black (K) toner images, respectively.

  In addition, the image forming process unit 110 includes an intermediate transfer belt 121 onto which the toner images of the respective colors formed on the photosensitive drums 25 of the image forming units 111Y, 111M, 111C, and 111K are transferred, and the image forming units 111Y. , 111M, 111C, and 111K toner images are sequentially transferred (primary transfer) to the intermediate transfer belt 121, and a primary transfer roll 122 as a primary transfer charging device and a superimposed toner image transferred onto the intermediate transfer belt 121 are recorded. A secondary transfer roll 123 as a secondary transfer charging device that performs batch transfer (secondary transfer) onto a paper P that is a material (recording paper), and a fixing device 125 that fixes the secondary transferred image onto the paper P. I have.

  The image forming process unit 110 performs an image forming operation based on a control signal such as a synchronization signal supplied from the control unit 130. At that time, image data input from the personal computer 102 or the image reading device 103 is subjected to image processing by the image processing unit 140 and supplied to each of the image forming units 111Y, 111M, 111C, and 111K via the interface. .

  For example, in the yellow image forming unit 111Y, the surface of the photosensitive drum 17 uniformly charged at a predetermined potential by the charging device 113 emits light based on the image data obtained from the image processing unit 140. The electrostatic latent image is formed on the photosensitive drum 17 by being exposed by the LED print head 1.

  This electrostatic latent image is developed by the developing device 115, and a yellow toner image is formed on the photosensitive drum 17. Similarly, magenta, cyan, and black toner images are formed on the respective photosensitive drums 17 of the image forming units 111M, 111C, and 111K.

  The respective color toner images formed on the respective photosensitive drums 17 of the respective image forming units 111Y, 111M, 111C, and 111K are sequentially transferred onto the intermediate transfer belt 121 that rotates in the direction of arrow A in FIG. A toner image superimposed on the intermediate transfer belt 121 is formed by electrostatic attraction.

  The superimposed toner image is conveyed to an area (secondary transfer portion) where the secondary transfer roll 123 is disposed as the intermediate transfer belt 121 rotates. When the superimposed toner image is conveyed to the secondary transfer unit, the paper P is supplied to the secondary transfer unit in accordance with the timing at which the toner image is conveyed to the secondary transfer unit.

  Then, the superimposed toner images are collectively electrostatically transferred onto the conveyed paper P by the transfer electric field formed by the secondary transfer roll 123 in the secondary transfer portion. Thereafter, the sheet P on which the superimposed toner image is electrostatically transferred is peeled off from the intermediate transfer belt 121 and conveyed to the fixing device 125 by the conveying belt 124.

  The unfixed toner image on the paper P conveyed to the fixing device 125 is fixed on the paper P by being subjected to fixing processing by heat and pressure by the fixing device 125. Then, the paper P on which the fixed image is formed is conveyed to a paper discharge placement unit (not shown) provided in the discharge unit of the digital color printer 131.

  That is, since the image forming apparatus according to the seventh embodiment includes the print head 1 according to the present invention, the image forming apparatus is affected by heat generation of the electronic component 9 due to image formation (ON / OFF operation of the light emitting element array 4). And a high-quality image can be formed.

  The above-described embodiments have been illustrated for the purpose of explanation, and the present invention is not limited thereto. Those skilled in the art will recognize from the claims, the detailed description of the invention, and the drawings. Modifications and additions can be made without departing from the technical idea of the present invention.

  For example, the dummy pattern 21 may connect a plurality of dummy patterns 21 and may have any shape.

  In the above embodiment, the wiring pattern 16 having the width dimension A of 100 microns is shown, but it may be 75 microns or 50 microns. Furthermore, in Example 6, the width dimension A = width dimension C = interval B = interval D may be 75 microns or 50 microns.

  The present invention is applied to a print head used in an image forming apparatus such as a copying machine or a printer, and a light emitting substrate device used in the print head.

DESCRIPTION OF SYMBOLS 1 Print head 4 Light emitting element array 5 Light emitting board | substrate apparatus 21 Dummy pattern 24 1st printed wiring board 25 2nd printed wiring board 28 Connection member 29 Area

Claims (5)

A long first printed wiring board in which a plurality of light emitting element arrays are mounted linearly or in a staggered pattern on the surface along the longitudinal direction;
A second printed wiring board on which electronic components for outputting a signal for driving the light emitting element array are mounted on the front surface and / or the back surface;
Light emission provided with a connection member for connecting the first printed wiring board and the second printed wiring board so that the back surface of the first printed wiring board faces the front surface of the second printed wiring board In substrate equipment,
A light emitting board device, wherein a dummy pattern is formed in an area occupied by the electronic component on the back surface of the first printed wiring board when viewed through the back surface of the second printed wiring board   The light emitting substrate device according to claim 1, wherein the dummy pattern is connected to a ground. The length in the longitudinal direction of the first printed wiring board is longer than the length in the longitudinal direction of the first printed wiring board in the second printed wiring board,
3. The light-emitting board device according to claim 1, wherein the dummy pattern is formed beyond an area of the first printed wiring board facing the second printed wiring board. A lens array in which a plurality of rod lenses are arranged and arranged;
A housing to which the lens array is fixed;
4. A print head comprising: the light emitting substrate device according to claim 1, which is fixed to the housing so that one lens surface of the lens array faces the light emitting element array. A photoreceptor that forms an electrostatic latent image on the surface;
An image forming apparatus comprising: the print head according to claim 4 fixed opposite to the photosensitive member.

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