JP5428591B2 - LED substrate device, LED print head, and image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a laser printer or a digital copying machine, an LED print head used in the image forming apparatus, and an LED substrate apparatus used in the LED print head.

  Conventionally, in order to form an electrostatic latent image of an image on an electrostatic latent image carrier such as a photosensitive drum of an image forming apparatus, an LED print head having an LED array chip and a lens array as main components has been used. ing.

  This LED print head has a long LED board device on which an LED array chip having a plurality of light emitting diodes (LEDs) is mounted (fixed), a long housing to which the LED board device is fixed, and the LED array chip. And a long lens array fixed to the housing (see, for example, Patent Documents 1 to 4).

In this LED print head, in order to form an electrostatic latent image on the surface of the photosensitive drum with high accuracy, it is necessary to minimize variations in image forming points.
Here, the imaging point refers to a point (focal point) where light emitted from a plurality of LEDs (light emitting points) of the LED array chip converges through the lens array.

  A generally adopted means for reducing the variation in the image formation point is to make the flatness and straightness of the housing for fixing the LED substrate device highly accurate, and to maintain this high accuracy over a long period of time. . For this reason, the LED print head described in Patent Document 1 and Patent Document 2 is integrally molded with a housing and a rigid body. Moreover, the LED print head described in patent documents 3 and 4 has made the height of the optical axis direction of a housing high.

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

  However, the above-described prior art is based on the premise that the flatness of the LED substrate device is poor, and does not improve the poor flatness of the LED substrate device itself.

This point will be further described in detail.
In general, a bare board used in an LED board device employs a printed board using a general-purpose glass epoxy base material (for example, FR-4) because of cost restrictions, productivity, and the like. Here, a glass epoxy base material means the thing of the structure which affixed copper foil to the glass cloth base material epoxy resin.

  The LED board device is manufactured by mounting an LED array chip or the like on such a bare board. At that time, heating and cooling are repeated. For example, 110 ° C. for 90 minutes in the curing process for mounting the LED array chip and curing the silver paste, and 250 ° C. for 5 seconds in the mounting process for electronic components such as drivers.

  Thus, in the manufacturing process of the LED substrate device, the flatness of the LED substrate device is deteriorated (distorted, warped, bent) by repeating heating and cooling. This is due to the difference in thermal expansion and contraction characteristics between the glass epoxy base material constituting the bare board and the copper foil attached to the glass epoxy base material.

  If the flatness of the LED substrate device is poor, it causes a deviation of the optical axis of the LED array chip, which becomes a serious problem in the print quality of the LED print head. In addition, the yield in the wire connection (wire bonding) process after the LED array chip is mounted is significantly deteriorated.

  The present invention has been made to solve the above-described problem, and has a simple configuration in which a dummy pattern is provided in an area where a wiring pattern is not formed, thereby adversely affecting the flatness due to heating and cooling of the LED substrate device. The object of the present invention is to reduce the cost and improve the yield of the LED board device, and hence the LED print head.

(First invention)
An LED substrate device according to a first aspect of the present invention is a long bare board, a solid pattern formed along the longitudinal direction of the bare board on the surface of the bare board, and fixed linearly or staggered on the solid pattern The plurality of LED array chips and the back surface area corresponding to the solid pattern formed on the front surface are formed with the same width dimension mainly along the longitudinal direction of the bare board. A plurality of wiring patterns that are electrically connected to the electronic components fixed on the bare board and arranged at equal intervals mainly in the short direction of the bare board in the set , the portion where the wiring pattern in the serial rear surface area is not formed along the longitudinal direction of the bare board, in the same width dimension and the width dimension of the wiring pattern, before Formed of the same interval as the plurality of wiring patterns in the lateral direction of the bare board, and a plurality of dummy patterns are not connected to the wiring pattern, to a LED board device having a.

  Here, the solid pattern does not indicate a portion such as a copper foil having a large area used for a power supply pattern, a ground pattern, or the like in a general printed wiring board, but LED array chips are mounted in a linear or staggered pattern. This refers to a portion of copper foil or the like having a large linear area.

  Here, the wiring pattern is an electronic component such as an LED array chip or IC (integrated circuit) mounted (fixed) on the bare board, and an electronic component mounted (fixed) on the bare boat and / or another bare board. Is a pattern for electrically connecting. That is, when it comes to the LED substrate device, it is a pattern directly related to the on (light emission) / off (non-light emission) operation of the LED array chip.

  On the other hand, the dummy pattern refers to a pattern of a picture or a pattern additionally formed on a bare board that is not intended for electrical connection (connection) between electronic components such as a wiring pattern. That is, when it comes to the LED substrate device, it is a pattern that does not directly participate in the on / off operation of the LED array chip. The wiring pattern, dummy pattern, and solid pattern described above are preferably made of the same material such as copper foil.

  The solid pattern formed on the surface of the LED substrate device is the most important part in the LED substrate device because the LED array chip is fixed, and the flatness of the solid pattern must be maintained with high accuracy.

  With the above-described configuration, the density of the wiring pattern (wiring pattern layout) in at least the back surface area corresponding to the solid pattern can be substantially uniform. Therefore, the most important part on which the LED array chip of the LED board device is mounted is the LED Deterioration of flatness due to heating and cooling in the manufacturing process of the substrate device can be suppressed (high flatness can be maintained). Moreover, the high flatness of the whole LED board apparatus is maintainable by providing a dummy pattern in the substantially whole area (substantially whole surface) of the back surface of an LED board apparatus.

(Second invention)
The LED board device according to a second invention is the LED board device according to the first invention, wherein the width dimension of the wiring pattern and the interval between the wiring patterns are the same.

  With this configuration, the density (layout) of the wiring pattern and the dummy pattern can be made more uniform than in the first invention, so that the effect of the first invention can be further improved. In other words, since the configuration of the wiring pattern and the dummy pattern in the area of the back surface corresponding to at least the solid pattern on the front surface repeats a certain pattern, the flatness of the LED substrate device deteriorates due to heating and cooling in the LED substrate device manufacturing process Can be further suppressed.

(Third invention)
In the LED substrate device according to a third aspect of the present invention, in the first or second aspect, all or part of the dummy pattern is connected by one or a plurality of second dummy patterns formed along the short direction of the bare board. (Concatenated).

  With this configuration, it is possible to counteract the back electromotive force caused by the magnetic field generated by charging / discharging the bypass capacitor that connects the power pattern and the ground pattern of the bare board, so that the noise generated by the LED board device can be reduced. effective.

(Fourth invention)
An LED substrate device according to a fourth aspect of the present invention is the one according to the first aspect, the second aspect or the third aspect, wherein the dummy pattern is connected to the ground.

  With this configuration, the dummy pattern not only contributes to maintaining high flatness of at least the area where the solid pattern is formed in the LED substrate device, but also has an effect of being a noise countermeasure (absorbing noise).

(Fifth invention)
In the LED substrate device of the fifth invention, in any one of the first to fourth inventions, an electronic component having leads protruding from both sides (both sides) of the main body is mounted on the back surface of the bare board. A dummy pattern is formed by extending a part of the back surface facing the main body.

  With this configuration, heat generated from the electronic component can be transmitted to the dummy pattern, so that heat can be efficiently radiated from the dummy pattern. For this reason, the fall of the light quantity of the light emission point of the LED array chip | tip caused by heat_generation | fever of an electronic component can be prevented.

(Sixth invention)
An LED print head according to a sixth aspect of the present invention is a lens array in which a plurality of rod lenses are arranged and arranged, a housing in which the lens array is fixed, and a housing in which one lens surface of the lens array faces the LED array chip. The LED board device according to any one of the first to fifth inventions fixed to the LED board device.

  With this configuration, since the flatness of the LED substrate device is high, it is possible to provide an LED print head with extremely small variations in image forming points.

  According to the present invention, it is possible to provide an LED substrate device that can maintain high flatness even when heated and cooled in the manufacturing process. In addition, since the flatness of the LED substrate device is high, it is possible to provide an LED print head with extremely small variations in image forming points. Furthermore, an image forming apparatus using this LED print head can form a high-quality image.

Plan view of LED print head (Example 1) LED print head perspective view (Example 1) Sectional view of LED print head (Example 1) Plan view of LED substrate device (Example 1) A perspective view of the surface of the LED substrate device (Example 1) A perspective view of the back surface of the LED substrate device (Example 1) A perspective view of the back surface of the LED substrate device (Example 1) Plan view of the back surface of the LED substrate device (Examples 1 and 6) Perspective view of the back surface of the LED substrate device (Example 2) Plan view of the back surface of the LED substrate device (Example 3) Perspective view of the back surface of the LED substrate device (Example 4) Plan view of the back surface of the LED substrate device (Example 5) Plan view of the back surface of the LED substrate device (Example 5) Plan view of the back side of the LED board device Plan view of the back side of the LED board device Plan view of the back side of the LED board device Plan view of the back surface of the LED substrate device (Example 7) Plan view of the back surface of the LED substrate device (Example 7) FIG. 8 is a diagram for explaining the configuration of an image forming apparatus (Embodiment 8). FIG. 8 is a diagram illustrating the positional relationship between an LED print head and a photoconductor (Example 8).

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.
(LED print head)
As shown in FIGS. 1 to 3, the LED 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 or the like, and one lens of the lens array 3. The LED board device 5 described later is fixed to the housing 2 with an adhesive or the like so that the LED array chip 4 faces the surface.

  As shown in FIG. 3, the LED print head 1 emits light from the light emitting point when the light emitting point (LED) of the LED array chip 4 mounted (fixed) on the surface 10 of the LED substrate device 5 is caused to 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. The conjugate length TC includes a distance L from the LED light emitting surface 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 imaging point, and the lens array. 4 and the height T, and the relationship TC = T + 2L is established.

  Further, as will be described later, since the flatness of the LED board device is high, and the high flatness of the LED board device can be maintained even by repeated temperature changes due to the on / off operation of the LED array chip, the LED print head according to the present invention. As shown in FIGS. 1 and 2, a rigid plate or the like is not required on the back surface of the LED substrate device. That is, it is possible to provide an inexpensive and high-accuracy LED print head with few LED print head components and little variation in image formation point.

  Although FIGS. 1 to 3 show the LED print heads fixed in a staggered pattern, they may be fixed in a straight line, and even in this case, the effects described above can be obtained. .

(LED board device)
An LED substrate device 5 according to the present invention is shown in FIGS. FIG. 5 is an enlarged perspective view of one end W surrounded by a two-dot chain line in FIG. 6 to 8 are perspective views or plan views of the back surface of the portion W. FIG.
In addition, the following description is only description about the one end part W in FIG. Description of parts other than the one end part W is omitted because it is a repetition of substantially the same configuration in which the LED array chip 4 is continuously fixed in a straight line or zigzag form from the one end part W to the other end.

  As shown in FIG. 5, the LED substrate device 5 includes a solid pattern 8 made of copper having a predetermined width on the front surface 10 along the longitudinal direction (Y direction), and a plurality of the same width dimension A on the back surface 11. The wiring pattern 16 includes a long bare board 9 formed mainly along the longitudinal direction (Y direction). A plurality of LED array chips 4 are fixed on the surface of the solid pattern 8 in a staggered manner.

  4 and 5 show the LED array chips 4 fixed in a zigzag pattern, the LED array chips 4 may be fixed in a straight line. Further, the width (X direction) of the solid pattern 8 may be any width that allows the LED array chip to be fixed in a straight line shape or a staggered shape.

  A light emitting point (LED) (not shown) is formed in a straight line on the surface of the LED array chip 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 of the bare board are connected by wires 12. In FIG. 5, only one pad 13 and 14 is shown for the sake of simplicity.

As shown in FIG. 6, a plurality of wiring patterns 16 (161 to 166) made of copper are mainly formed along the longitudinal direction of the bare board 9 on the back surface 11 of the bare board 9.
Here, “the wiring pattern 16 is mainly formed along the longitudinal direction” means that most of the wiring pattern 16 (most of the entire length of the wiring pattern 16) is formed along the longitudinal direction (Y direction). It means that More specifically, for example, a wiring pattern along the longitudinal direction (Y direction) excluding a part of the wiring pattern 16 in the short direction (X direction) such as connecting to the IC (integrated circuit) 19 in FIG. 16 is the majority.

  These wiring patterns 16 are divided into two sets (wiring pattern bundles): a first set of wiring patterns 161, 162, and 163 and a second set of wiring patterns 164, 165, and 166. The wiring patterns 16 are arranged at intervals B equal to the short direction (X direction) of the bare board 9 in each set.

  That is, the width dimension of the first set of wiring patterns 161, 162, and 163 is A, the distance between the wiring patterns 161 and 162 is B, and the distance between the wiring patterns 162 and 163 is also B. The width dimension of the second set of wiring patterns 164, 165 and 166 is A, the distance between the wiring patterns 164 and 165 is B, and the distance between the wiring patterns 165 and 166 is also B.

Further, as shown in FIG. 6, on the back surface 11 of the bare board 9, there is at least a wiring pattern 16 in an area 18 (a portion surrounded by a two-dot chain line) corresponding to the solid pattern 8 formed on the front surface 10 of the bare board 9. As shown in FIGS. 7 and 8, a plurality of dummy patterns 21 made of copper are mainly formed along the longitudinal direction (Y direction) of the bare board 9 in the unformed area (portion) 20.
Here, “the area 18 of the back surface 11 corresponding to the solid pattern 8 formed on the front surface 10” refers to a portion occupied in the back surface 11 when the solid pattern 8 formed on the front surface 10 is seen through the back surface 11. Say.

As shown in FIG. 8, the width dimension C of each of the five dummy patterns 21 formed on the back surface 11 is the same as the width dimension A of the wiring pattern 16. Further, the distance D between the dummy patterns 21 is the same as the distance B between the wiring patterns 16 in the short direction (X direction) of the bare board 9.
In Example 1, the width dimension C = the width dimension A = 150 microns, and the interval D = the interval B = 100 microns.

  With this configuration, in the area 18 on the back surface 11 corresponding to the solid pattern 8 formed on the front surface 10 of the bare board 9, the density of the wiring pattern 16 and the dummy pattern 21 can be made substantially uniform, that is, the predetermined pattern is present / absent. Since the repetition is constant, even when heating and cooling are repeated in the manufacturing process of the LED substrate device 5, the flatness of the solid pattern 8 does not deteriorate due to warpage of the solid pattern 8 in the LED substrate device 5 (initially) High flatness).

  Moreover, even if the heating and cooling of the LED substrate device 5 are repeated by the on / off operation of the plurality of LED array chips 4 fixed to the solid pattern 8, the initial high flatness of the solid pattern 8 can be maintained.

  For this reason, since the optical axis of the LED array chip 4 fixed to the solid pattern 8 formed on the surface 10 is not shifted, when the LED substrate device 5 is used for the LED print head 1 described above, the LED array chip The imaging lines formed by the plurality of imaging points formed by the light emitted from the plurality of light emitting points 4 passing through the lens array 3 can maintain linearity with high accuracy. That is, the image forming apparatus using the LED print head 1 can form a high-precision electrostatic latent image on the surface of the photosensitive drum, and can form a high-precision image on recording paper or the like.

A second embodiment according to the present invention will be described with reference to FIG.
Note that only differences from the first embodiment will be described for easy understanding.

The second embodiment is different from the first embodiment in that a dummy pattern 21 is provided in a portion other than the area 18 in FIG. 7 of the first embodiment.
In the case of such a configuration, the density of the wiring pattern 16 and the dummy pattern 21 can be made substantially uniform over the entire back surface of the bare board 9, so that the effect of the first embodiment can be further improved.

  That is, high flatness of the LED substrate device 5 as a whole can be maintained against repeated heating and cooling also in the portion other than the portion 18 corresponding to the back surface 11 where the solid pattern 8 is formed on the front surface 10.

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 first embodiment are denoted by the same reference numerals and the description thereof is omitted.

The difference of the third embodiment from the first embodiment is only that the through holes 22 are provided in all the dummy patterns 21 and connected (grounded) to the ground.
In FIG. 10, a ground (not shown) is formed in the inner layer of the bare board 9, and all the dummy patterns 21 are connected to the ground using the through holes 22.

  With this configuration, the dummy pattern 21 not only contributes to maintaining high flatness of the LED board device 5, but also has an effect that the dummy pattern also serves as a noise countermeasure that allows noise to escape to the ground. That is, in addition to the effects described in the first embodiment, an LED substrate device that is resistant to noise can be provided.

  In FIG. 10, all the dummy patterns 21 are grounded. However, some of the dummy patterns 21 may be grounded. Further, as shown in FIG. 9, dummy patterns 21 may also be formed in portions other than the area 18, and all or some of the dummy patterns 21 may be connected to the ground.

A fourth 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 first embodiment are denoted by the same reference numerals and the description thereof is omitted.

  The fourth embodiment is different from the first embodiment in that a part of the dummy patterns 21 are connected (linked) by the second dummy pattern 23 made of copper formed along the short direction (X direction) of the bare board 9. Is different.

  With such a configuration, not only the effects of the first embodiment described above can be obtained, but also generated due to charging / discharging of the bypass capacitor 7 connecting the power supply pattern (inner layer 1) and the ground pattern (inner layer 2) (not shown) of the bare board 9. Since the counter electromotive force caused by the magnetic field to be applied can be canceled, the noise generated by the LED board device 5 can be reduced.

  In addition, as shown in FIG. 9, the dummy pattern 21 is also formed in portions other than the area 18, and all or a part of the dummy pattern 21 is formed along the short direction (X direction) of the bare board 9. You may connect (connect) by the dummy pattern 23. FIG.

A fifth 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 first embodiment are denoted by the same reference numerals and the description thereof is omitted.

  The difference of the fifth embodiment from the first embodiment is that all the dummy patterns 21 are connected (linked) by the second dummy patterns 23 formed along the short direction (X direction) of the bare board 9. A through hole 22 is formed in a part of the dummy pattern 21, and the dummy pattern 21 is connected to a ground (inner layer) (not shown) through the through hole 22.

  With this configuration, not only the effects of the first and third embodiments described above can be obtained, but also charging / discharging of the bypass capacitor 7 connecting the power supply pattern (inner layer 1) and the ground pattern (inner layer 2) (not shown) of the bare board 9 Since the counter electromotive force due to the magnetic field generated by the discharge can be canceled, there is an effect that the noise generated by the LED substrate device 5 can be reduced.

  As shown in FIG. 9, the dummy pattern 21 is formed also in the portion other than the area 18, and the second dummy pattern 23 in which all the dummy patterns 21 are formed along the short direction (X direction) of the bare board 9. Needless to say, they may be connected (linked).

The difference between the sixth embodiment and the first embodiment is that the width dimension of the wiring pattern and the interval between the wiring patterns are the same.
This will be described in further detail with reference to FIG. That is, the width dimension C of each of the five dummy patterns 21 formed on the back surface 11 is the same as the width dimension A of the wiring pattern 16, and the interval D between the dummy patterns 21 is short of the bare board 9. It is the same as the interval B of the wiring pattern 16 in the direction (X direction). Furthermore, in the sixth embodiment, since the width C of the wiring pattern and the interval B of the wiring pattern are made the same, width A = width C = interval B = interval D = 100 microns.

  With this configuration, the density of the wiring pattern 16 and the dummy pattern 21 can be made more uniform than in the case of the first embodiment, so that the effect of the first embodiment can be further improved. That is, since the configuration of the wiring pattern 16 and the dummy pattern 21 in the back surface area 18 corresponding to at least the solid pattern 8 on the front surface 10 repeats a certain pattern, the LED substrate is heated and cooled in the manufacturing process of the LED substrate device 5. The deterioration of the flatness of the device 5 can be further suppressed.

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

  The difference between the seventh embodiment and the first embodiment is that, as shown in FIG. 17, for example, a SOP (Small Outline Package) type resistor in which leads 52 protrude from both side surfaces of the main body 51 on the back surface 11 of the bare board 9. An electronic component 50 such as an array is mounted, and the dummy pattern 21 is formed to extend on a part of the back surface 11 facing the main body 51.

  The electronic component 50 is composed of a main body 51 and a total of six leads 52 protruding from both sides of the main body 50 (the vertical direction in FIG. 17). FIG. 18 shows the electronic component 50 removed from FIG. As can be seen from FIG. 18, the dummy pattern 53 extends to the area of the back surface 11 facing the main body 51 of the electronic component 50.

  With this configuration, heat generated from the electronic component 50 can be transmitted to the dummy pattern 53 facing the main body 51 of the electronic component 50. For this reason, the heat | fever of the electronic component 50 can be thermally radiated efficiently and the fall of the light quantity of the light emission point of the LED array chip | tip caused by the heat_generation | fever of the electronic component 50 can be prevented.

  Although illustration is omitted, it goes without saying that the configuration of the second to sixth embodiments described above can also be adopted in the seventh embodiment. In FIG. 17, the three dummy patterns 53 of the electronic component 50 facing the main body 51 of the electronic component 50 are shown. However, the number of patterns may be determined according to the size of the main body 51. One, two, or four or more may be used. Further, in this embodiment, the back surface of the main body 51 of the electronic component 50 and the dummy pattern 53 facing the main body 51 of the electronic component 50 are shown in a non-contact manner. If not, both may be in contact.

  An eighth embodiment according to the present invention will be described with reference to FIGS. 20 is a partially enlarged view of a part of FIG. 19 in order to make the positional relationship between the LED print head 1 and the photosensitive drum 25 easy to understand.

(Image forming device)
As shown in FIG. 19, the image forming apparatus according to the present invention is a so-called tandem digital color printer 131. The image forming process unit 110 and the image forming process unit 110 perform image formation corresponding to image data of each color. 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 these image forming units 111Y, 111M, 111C, and 111K forms a latent image on the photosensitive drum 25 as an image carrier that carries a toner image, and the surface of the photosensitive drum 25. The charging device 113 that is uniformly charged at a predetermined potential, the LED print head 1 as an exposure device that exposes the photosensitive drum 25 whose surface is charged by the charging device 113, and the electrostatic latent image obtained by the LED print head 1 A developing device 115 for developing an image and a cleaner (blade) 116 for cleaning the surface of the photosensitive drum 25 after transfer are provided.

  Further, a density detection circuit 117 that detects the toner image density of a test patch (density sample) formed on the photosensitive drum 25 is provided in the vicinity of the downstream side of the developing device 115 so as to face the photosensitive drum 25. 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 25 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 25 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 25. Similarly, magenta, cyan, and black toner images are formed on the respective photosensitive drums 25 of the image forming units 111M, 111C, and 111K.

  The color toner images formed on the respective photosensitive drums 25 of the image forming units 111Y, 111M, 111C, and 111K are sequentially transferred by the primary transfer roll 122 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 eighth embodiment includes the LED print head 1 according to the present invention, 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 number and location of the second dummy patterns 23 are not limited as long as they connect the dummy patterns 21. Specifically, as shown in FIGS. 13 to 16, the dummy patterns 21 may be connected to each other using a plurality of second dummy patterns 23.

  In this configuration, as shown in FIG. 9, dummy patterns 21 are also formed in portions other than the area 18, and all or part of the dummy patterns 21 are formed along the short direction (X direction) of the bare board 9. It may be extended so as to be connected (linked) by two dummy patterns 23.

  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 an LED print head used in a copying machine, a printer, and the like, and an LED substrate device used in the LED print head.

DESCRIPTION OF SYMBOLS 1 LED print head 2 Housing 3 Lens array 4 LED array chip 5 LED board device 6 Rod lens 8 Solid pattern 9 Bare board 10 Front surface 11 Back surface 16 Wiring pattern 17 Test pad 21 Dummy pattern 23 2nd dummy pattern

Claims (7)

With a long bare board,
On the surface of the bare board, a solid pattern formed along the longitudinal direction of the bare board;
A plurality of LED array chips fixed in a linear or staggered pattern on the solid pattern;
In the area of the back surface corresponding to the solid pattern formed on the front surface, it is mainly formed with the same width dimension along the longitudinal direction of the bare board, and is divided into a plurality of sets of three or more, A plurality of wiring patterns that are arranged at equal intervals mainly in the short direction of the bare board and electrically connected to electronic components fixed on the bare board;
At least, before Symbol portion where the wiring pattern on the rear surface of the area is not formed along the longitudinal direction of the bare board, in the same width dimension and the width dimension of the wiring pattern, the plurality in the lateral direction of the bare board A plurality of dummy patterns that are formed at the same interval as the wiring pattern interval and are not connected to the wiring pattern ;
LED board device provided with   The LED board device according to claim 1, wherein a width dimension of the wiring pattern and an interval between the wiring patterns are the same. 3. The LED board device according to claim 1, wherein all or part of the dummy patterns are connected by one or a plurality of second dummy patterns formed along a short direction of the bare board.   The LED substrate device according to claim 1, wherein the dummy pattern is connected to ground.   2. An electronic component having leads protruding from both sides of a main body portion is mounted on the back surface of the bare board, and the dummy pattern is extended and formed on a part of the back surface facing the main body portion. LED substrate device as described in any one of -4 A lens array in which a plurality of rod lenses are arranged and arranged;
A housing to which the lens array is fixed;
6. An LED print head comprising: the LED substrate device according to claim 1, which is fixed to the housing so that one lens surface of the lens array faces the LED array chip. A photoreceptor that forms an electrostatic latent image on the surface;
An image forming apparatus comprising the LED print head according to claim 6 fixed to face the photosensitive member.

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