JP2010052160A - Line head and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a line head capable of preventing unwilling electromagnetic influences between each light emitting element and the outside from occurring while the cost of a supporting member is suppressed and stably performing highly precise light exposure processing, and to provide an image forming apparatus capable of obtaining an image with low cost and high quality. <P>SOLUTION: The line head 13 has the supporting member 6 and a light emitting substrate unit 7 equipped with a longitudinal substrate 71 supported by the supporting member 6, and a plurality of the light emitting elements 72 aligned along the longitudinal direction on the substrate 71. The supporting member 6 is manufactured by bend-processing a metal plate so as to cover the light emitting substrate unit 7 while permitting the outgoing radiation of the light from each light emitting element 72. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a line head and an image forming apparatus having the line head.

An image forming apparatus such as a copying machine or a printer using an electrophotographic system is provided with an exposure unit that exposes the outer surface of a photoreceptor, and a line head is known as such an exposure unit (for example, , See Patent Document 1).
For example, in the line head according to Patent Document 1, an organic EL light emitting element array including organic EL light emitting elements arranged in the main scanning direction, and a gradient index rod provided on the light emission side of the organic EL light emitting element array A lens array; and a housing that supports the gradient index rod lens array and the organic EL light emitting element array.
In such a line head, an organic EL light emitting element array is housed in a housing, and the housing has a complicated shape so as to cover the organic EL light emitting element array. Such a housing having a complicated shape is usually formed of a resin material using an injection molding method.

However, if the housing is made of a resin material, the organic EL light emitting element array may be subject to unintentional electromagnetic influence (electromagnetic adverse effect) from the outside. Therefore, noise may be mixed in the organic EL light emitting element array due to electromagnetic influence from the outside, and the exposure processing characteristics may be deteriorated. Further, in an image forming apparatus provided with such a line head, an unintentional electromagnetic influence is exerted on the outside (another electric circuit in the image forming apparatus) from the organic EL light emitting element array. In some cases, the quality may deteriorate.
If a metal injection molding method or the like is used, the support member of Patent Document 1 can be made of a metal material. In this case, although the above-described electromagnetic adverse effects can be prevented, the manufacturing cost of the housing is extremely high. It will be high.

JP 2004-66758 A

  An object of the present invention is to provide a line head capable of stably performing high-precision exposure processing while preventing unintentional electromagnetic influence between each light emitting element and the outside while suppressing the cost of a support member. It is another object of the present invention to provide an image forming apparatus that can obtain an inexpensive and high-quality image.

Such an object is achieved by the present invention described below.
The line head of the present invention includes a support member,
A substrate supported by the support member, and a light emitting substrate unit including a light emitting element disposed on the substrate,
The support member is formed by bending a metal plate so as to cover the light emitting substrate unit while allowing the light from the light emitting element to be emitted from the light emitting substrate unit.

In the line head according to the aspect of the invention, it is preferable that the support member includes a support portion that supports the substrate and a leg portion that is perpendicular or substantially perpendicular to the support portion.
The line head of the present invention includes a drive circuit for driving the light emitting element and a control circuit for controlling the operation of the drive circuit, and the support member is disposed so as to cover the drive circuit. It is preferable that

In the line head according to the aspect of the invention, it is preferable that the support member is disposed so as to cover the control circuit.
In the line head according to the aspect of the invention, it is preferable that the line head includes a lens array provided on the light emission side of the light emitting substrate unit, and the support member shields light that has not entered the lens array from the light emitting element. .
In the line head according to the aspect of the invention, it is preferable that the substrate is bonded to the support member via a spacer.
In the line head according to the aspect of the invention, it is preferable that the spacer is a light-transmitting substrate, is optically bonded to the lens array, and supports the lens array.

The image forming apparatus of the present invention includes a photoreceptor,
A line head, and
The line head is
A support member;
A light-emitting substrate unit including a substrate supported by the support member and a light-emitting element disposed on the substrate;
The support member is formed by bending a metal plate so as to cover the light emitting substrate unit while allowing light from each light emitting element to be emitted from the light emitting substrate unit.

  According to the line head of the present invention having the above-described configuration, it is possible to prevent unintentional electromagnetic influence between each light emitting element and the outside while suppressing the cost of the support member, and to stably perform high-precision exposure processing. Can be done automatically. Further, according to the image forming apparatus of the present invention, an inexpensive and high-quality image can be obtained.

Hereinafter, a line head and an image forming apparatus according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.
<First Embodiment>
FIG. 1 is a schematic diagram showing the overall configuration of the image forming apparatus according to the first embodiment of the present invention, FIG. 2 is a partial sectional perspective view of a line head provided in the image forming apparatus shown in FIG. 1, and FIG. 2 is a cross-sectional view of the line head shown in FIG. 2, FIG. 4 is a cross-sectional view showing a schematic configuration of a light emitting element provided in the line head shown in FIG. 2, and FIG. 5 is a control system of the line head shown in FIG. It is a block diagram which shows a structure. In the following, for convenience of explanation, the upper side in FIGS. 1 to 3 is referred to as “upper” and the lower side is referred to as “lower”.

(Image forming device)
An image forming apparatus 1 shown in FIG. 1 is an electrophotographic printer that records an image on a recording medium P through a series of image forming processes including a charging process, an exposure process, a developing process, a transfer process, and a fixing process. In the present embodiment, the image forming apparatus 1 is a color printer that employs a so-called tandem method.

As shown in FIG. 1, the image forming apparatus 1 includes an image forming unit 10 for a charging process, an exposure process, and a developing process, a transfer unit 20 for a transfer process, and a fixing unit for a fixing process. 30, a transport mechanism 40 for transporting a recording medium P such as paper, and a paper feed unit 50 that supplies the recording medium P to the transport mechanism 40.
The image forming unit 10 includes an image forming station 10Y that forms a yellow toner image, an image forming station 10M that forms a magenta toner image, an image forming station 10C that forms a cyan toner image, and a black toner image. Four image forming stations including an image forming station 10K to be formed are provided.

  Each of the image forming stations 10Y, 10C, 10M, and 10K has a photosensitive drum (photosensitive member) 11 that carries an electrostatic latent image, and a charging unit 12 and a line head are provided around (outer peripheral side). An (exposure unit) 13, a developing device 14, and a cleaning unit 15 are provided. Here, the image forming stations 10Y, 10C, 10M, and 10K have substantially the same configuration except that the color of the toner used is different.

The photosensitive drum 11 has a cylindrical shape as a whole, and can rotate around the axis in the direction of the arrow in FIG. A photosensitive layer (not shown) is provided near the outer peripheral surface (cylindrical surface) of the photosensitive drum 11. The outer peripheral surface of the photosensitive drum 11 has a light receiving surface 111 that receives light L (emitted light) from the line head 13.
The charging unit 12 uniformly charges the light receiving surface 111 of the photosensitive drum 11 by corona charging or the like.

  The line head 13 receives image information from a host computer such as a personal computer (not shown) and irradiates the light L toward the light receiving surface 111 of the photosensitive drum 11 in response to the image information. When the light L is irradiated on the light receiving surface 111 of the uniformly charged photosensitive drum 11, a latent image (electrostatic latent image) corresponding to the irradiation pattern of the light L is formed on the light receiving surface 111. The configuration of the line head 13 will be described in detail later.

The developing device 14 has a storage unit (not shown) that stores toner, and supplies and applies toner from the storage unit to the light receiving surface 111 of the photosensitive drum 11. When toner is applied to the light receiving surface 111, an electrostatic latent image formed on the light receiving surface 111 is visualized (developed) as a toner image.
The cleaning unit 15 has a rubber cleaning blade 151 that abuts on the light receiving surface 111 of the photosensitive drum 11, so that the toner remaining on the photosensitive drum 11 after the primary transfer described later is scraped off and removed by the cleaning blade 151. It has become.

The transfer unit 20 collectively transfers the toner images of the respective colors formed on the photosensitive drums 11 of the image forming stations 10Y, 10M, 10C, and 10K as described above to the recording medium P.
In each of the image forming stations 10Y, 10C, 10M, and 10K, the charging unit 12 charges the light receiving surface 111 of the photosensitive drum 11 and the line head 13 exposes the light receiving surface 111 while the photosensitive drum 11 rotates once. Then, supply of toner to the light receiving surface 111 by the developing device 14, primary transfer of a toner image to the intermediate transfer belt 21 by a primary transfer roller 22 described later, and cleaning of the light receiving surface 111 by the cleaning unit 15 are sequentially performed.

The transfer unit 20 includes an endless belt-like intermediate transfer belt 21, and the intermediate transfer belt 21 includes a plurality of (four in the configuration shown in FIG. 1) primary transfer rollers 22, drive rollers 23, and driven rollers 24. It is stretched, and is driven to rotate in the direction of the arrow shown in FIG.
Each primary transfer roller 22 is disposed opposite to the corresponding photosensitive drum 11 via an intermediate transfer belt 21, and transfers a single color toner image on the photosensitive drum 11 to the intermediate transfer belt 21 (primary transfer). It is like that. At the time of primary transfer, the primary transfer roller 22 is applied with a primary transfer voltage (primary transfer bias) having a polarity opposite to the charging polarity of the toner.

On the intermediate transfer belt 21, a toner image of at least one of yellow, magenta, cyan, and black is carried. For example, when a full-color image is formed, four color toner images of yellow, magenta, cyan, and black are sequentially transferred onto the intermediate transfer belt 21 to form a full-color toner image as an intermediate transfer image.
Further, the transfer unit 20 includes a secondary transfer roller 25 disposed to face the driving roller 23 via the intermediate transfer belt 21, and a cleaning unit 26 disposed to face the driven roller 24 via the intermediate transfer belt 21. have.

The secondary transfer roller 25 transfers a single-color or full-color toner image (intermediate transfer image) formed on the intermediate transfer belt 21 to a recording medium P such as paper, film, or cloth supplied from the paper supply unit 50. (Secondary transfer). The secondary transfer roller 25 is pressed against the intermediate transfer belt 21 and applied with a secondary transfer voltage (secondary transfer bias) during secondary transfer. During such secondary transfer, the drive roller 23 also functions as a backup roller for the secondary transfer roller 25.
The cleaning unit 26 has a rubber cleaning blade 261 that contacts the surface of the intermediate transfer belt 21, and the toner remaining on the intermediate transfer belt 21 after the secondary transfer is scraped off and removed by the cleaning blade 261. It has become.

The fixing unit 30 includes a fixing roller 301 and a pressure roller 302 that is pressed against the fixing roller 301, and is configured such that the recording medium P passes between the fixing roller 301 and the pressure roller 302. Yes. In addition, a heater 303 that heats the outer peripheral surface of the fixing roller 301 is built in the fixing roller 301. In the fixing unit 30 having such a configuration, the recording medium P that has received the secondary transfer of the toner image is heated and pressed while passing between the fixing roller 301 and the pressure roller 302, whereby the toner image is transferred. It is fused to the recording medium P and fixed as a permanent image.
The conveyance mechanism 40 includes a registration roller pair 41 that conveys the recording medium P while feeding the recording medium P to the secondary transfer portion between the secondary transfer roller 25 and the intermediate transfer belt 21 described above, and fixing by the fixing unit 30. Conveying roller pairs 42, 43, and 44 for nipping and conveying the processed recording medium P are provided.

When such a transport mechanism 40 forms an image on only one surface of the recording medium P, the transport mechanism 40 sandwiches and transports the recording medium P fixed on one surface by the fixing unit 30 by the transport roller pair 42. Then, it is discharged outside the image forming apparatus 1. When forming an image on both surfaces of the recording medium P, the recording medium P fixed on one surface by the fixing unit 30 is once sandwiched by the conveying roller pair 42 and then the conveying roller pair 42 is driven to reverse. Then, the pair of conveying rollers 43 and 44 are driven, the recording medium P is turned upside down and returned to the registration roller pair 41, and an image is formed on the other surface of the recording medium P by the same operation as described above.
The paper feeding unit 50 includes a paper feeding cassette 51 that stores unused recording media P, and a pickup roller 52 that feeds the recording media P from the paper feeding cassette 51 to the registration roller pair 41 one by one. .

(Line head)
Next, the line head 13 will be described.
The line head 13 is disposed to face the outer peripheral surface (that is, the light receiving surface 111) of the photosensitive drum 11 (see FIGS. 1 and 3).
As shown in FIG. 2, the line head 13 includes a support member 6, a light emitting substrate unit 7, a lens array 16, and a spacer 171.

In such a line head 13, the light L emitted from the light emitting substrate unit 7 passes through the spacer 171 and the lens array 16 and is irradiated onto the light receiving surface 111 of the photosensitive drum 11.
Hereinafter, each part which comprises the line head 13 is demonstrated in detail sequentially. Hereinafter, for convenience of explanation, the longitudinal direction of the substrate 71 of the light emitting substrate unit 7 is referred to as a “main scanning direction”, and the width direction is referred to as a “sub scanning direction”.

The support member 6 has a long shape (longitudinal shape) and is installed along the axial direction (main scanning direction) of the photosensitive drum 11.
The support member 6 includes a support portion 61 that supports the substrate 71 and a pair of leg portions 62 that are perpendicular or substantially perpendicular to the support portion 61. That is, the cross-sectional shape of the support member 6 is substantially U-shaped.
The support portion 61 is provided along the plate surface of the substrate 71 in a cross section shown in FIG. 3 (a cross section perpendicular to the longitudinal direction of the substrate 71 described later). In addition, the pair of leg portions 62 has a cross section shown in FIG. 3 (a cross section perpendicular to the longitudinal direction of the substrate 71 to be described later) from both ends of the support portion 61 in the width direction (sub-scanning direction). It extends to the side.

A light emitting substrate unit 7 to be described later is disposed between one surface side (lower side in FIG. 3) of the support portion 61 of the support member 6, that is, between the pair of leg portions 62. In other words, the light emitting substrate unit 7 is provided inside the support member 6. Accordingly, the support member 6 is provided so as to cover the light emitting substrate unit 7.
Further, an opening 611 penetrating in the thickness direction is formed in the support portion 61 of the support member 6, and the lens array 16 is provided so as to face the outside from the inside of the support member 6 through the opening 611. ing.

Thus, the support member 6 is formed so as to cover the light emitting substrate unit 7 while allowing light from each light emitting element 72 of the light emitting substrate unit 7 to be described later to be emitted from the light emitting substrate unit 7. The support member 6 is obtained by bending a metal plate. Such a support member 6 functions as an electromagnetic shield for preventing unintended electromagnetic influence between the light emitting substrate unit 7 and the outside.
Such a support member 6 is obtained by bending a metal plate, and therefore can be obtained relatively easily and inexpensively. As a result, unintentional electromagnetic influence between each light emitting element 72 and the outside can be prevented while suppressing the cost of the support member 6, and high-precision exposure processing can be performed stably.

In particular, as described above, the light emitting board unit 7 can be covered with the support member 6 with a relatively simple structure by configuring the support member 6 so that the cross section of the support member 6 is substantially U-shaped. Moreover, the rigidity of the support member 6 can be made excellent. Furthermore, by supporting the substrate 71 with the support portion 61, the substrate 71 can be stably supported and a stable exposure process can be performed.
Further, the support member 6 has a light shielding property. Therefore, the support member 6 also has a function of shielding light that has not entered the lens array 16 described later from each light emitting element 72. Thereby, high-precision exposure processing can be performed at low cost without separately providing a light shielding member.

The constituent material of the support member 6 is not particularly limited, and various metal materials (particularly soft magnetic materials) can be used, but iron, stainless steel, aluminum alloy, and the like are preferably used.
The light emitting substrate unit 7 includes an elongated substrate 71, a plurality of light emitting elements 72 arranged along the longitudinal direction on one surface side of the substrate 71, and a cover member 73 that covers the plurality of light emitting elements 72. It has.

The board | substrate 71 supports each light emitting element 72, and is comprised with the plate-shaped body from which an external shape makes long shape. Note that the shape of the substrate 71 does not have to be long, and for example, a plurality of substrates may be arranged in parallel in the main scanning direction.
Although it does not specifically limit as a constituent material of the board | substrate 71, For example, various metal materials, such as aluminum and stainless steel, various glass materials, various plastics, etc. can be used individually or in combination.

  In the present embodiment, the substrate 71 has an insulating property. Since each light emitting element 72 is an element having a bottom emission structure as will be described later, the substrate 71 is substantially transparent (colorless transparent, colored transparent or translucent). Examples of such materials include resin materials such as polyethylene terephthalate, polyethylene naphthalate, polypropylene, cycloolefin polymer, polyamide, polyether sulfone, polymethyl methacrylate, polycarbonate, polyarylate, quartz glass, and soda glass. Such glass materials can be used, and one or more of these can be used in combination.

When the substrate 71 is made of various metal materials or various glass materials, heat generated by light emission of each light emitting element 72 can be efficiently radiated through the substrate 71. Moreover, when the board | substrate 71 is comprised with various plastics, it contributes to the weight reduction of the board | substrate 71. FIG.
In such a substrate 71, a plurality of light emitting elements 72 and a cover member 73 are joined to one surface (lower surface in FIG. 3), and the other surface (upper surface in FIG. 3) The lens array 16 is bonded via the spacer 171.

The plurality of light emitting elements 72 are arranged on the substrate 71 along the longitudinal direction (main scanning direction).
Each light emitting element 72 is configured by an organic EL element (organic electroluminescence element).
More specifically, each light emitting element 72 includes an anode 722, an organic semiconductor layer 723 provided on the anode 722, a cathode 724 provided on the organic semiconductor layer 723, as shown in FIG. And a protective layer 725 provided so as to cover each of the layers 722, 723, and 724, and these are provided on the substrate 71.

Further, in the present embodiment, the organic semiconductor layer 723 is a laminate composed of a plurality of layers laminated in this order from the anode 722 side, the hole transport layer 726, the light emitting layer 727, and the electron transport layer 728. Yes.
In such a light emitting element 72, when a DC voltage is applied between the anode 722 and the cathode 724, the electrons transported through the electron transport layer 728 and the hole transport layer in the light emitting layer 727 are thereby generated. The holes transported through 726 recombine, and the exciton (exciton) is generated by the energy released during the recombination. When the exciton returns to the ground state, the energy (fluorescence or phosphorescence) is light. Released as L. Thereby, the light emitting element 72 (light emitting layer 727) emits light.

In the present embodiment, the light emitting element 72 is an element having a bottom emission structure in which the light L from the light emitting layer 727 is extracted and used on the anode 722 side.
The anode 722 is an electrode that injects holes into the organic semiconductor layer 723 (a hole transport layer 726 described later). The constituent material of the anode 722 is not particularly limited, but includes, for example, ITO (Indium Tin Oxide), SnO ₂ , Sb-containing SnO ₂ , oxides such as Al-containing ZnO, Au, Pt, Ag, Cu or the like. An alloy etc. are mentioned, At least 1 sort (s) of these can be used.

The cathode 724 is an electrode that injects electrons into the organic semiconductor layer 723 (an electron transport layer 728 described later). The cathode 724 also has a function as a reflective film that reflects the light L leaked to the cathode 724 side to the anode 722 side. Thereby, more light quantity of the light L which goes to the lens array 16 side can be ensured.
Examples of the constituent material of the cathode 724 include Li, Mg, Ca, Sr, La, Ce, Er, Eu, Sc, Y, Yb, Ag, Cu, Al, Cs, Rb, and alloys containing these. At least one of them can be used.

An organic semiconductor layer 723 is provided between the anode 722 and the cathode 724. As described above, the organic semiconductor layer 723 includes the hole transport layer 726, the light emitting layer 727, and the electron transport layer 728, which are stacked on the anode 722 in this order.
The hole transport layer 726 has a function of transporting holes injected from the anode 722 to the light emitting layer 727.
The constituent material (hole transport material) of the hole transport layer 726 may be any material as long as it has a hole transport capability, but is preferably a conjugated compound. A conjugated compound is particularly excellent in hole transport capability because it can transport holes very smoothly due to the property of its unique electron cloud spread.

Examples of such hole transport materials include arylcycloalkane compounds such as 1,1-bis (4-di-para-triaminophenyl) cyclohexane, 4,4 ′, 4 ″ -trimethyl. Arylamine compounds such as triphenylamine, phenylenediamine compounds such as N, N, N ′, N′-tetraphenyl-para-phenylenediamine, triazole compounds such as triazole, imidazoles such as imidazole Compounds, oxadiazole compounds such as 1,3,4-oxadiazole, anthracene compounds such as anthracene, fluorenone compounds such as fluorenone, aniline compounds such as polyaniline, phthalocyanine compounds such as phthalocyanine Compounds, etc., one or more of these It can be used in combination.
The electron transport layer 728 has a function of transporting electrons injected from the cathode 724 to the light emitting layer 727.

As a constituent material (electron transport material) of the electron transport layer 728, for example, 1,3,5-tris [(3-phenyl-6-tri-fluoromethyl) quinoxalin-2-yl] benzene (TPQ1) is used. Benzene compounds (starburst compounds), naphthalene compounds such as naphthalene, phenanthrene compounds such as phenanthrene, chrysene compounds such as chrysene, perylene compounds such as perylene, anthracene compounds such as anthracene, An oxadiazole-based compound such as oxadiazole, a triazole-based compound such as triazole, and the like can be given, and one or more of these can be used in combination.
The light-emitting layer 727 is formed of a constituent material that can inject holes from the anode 722 side when a voltage is applied and electrons from the cathode 724 side and can provide a field where holes and electrons recombine. Any one can be used.

As a constituent material (light emitting material) of the light emitting layer 727, 1,3,5-tris [(3-phenyl-6-tri-fluoromethyl) quinoxalin-2-yl] benzene (TPQ1), 1,3 , 5-tris [{3- (4-t-butylphenyl) -6-trisfluoromethyl} quinoxalin-2-yl] benzene (TPQ2), phthalocyanine, copper phthalocyanine (CuPc), iron phthalocyanine Low molecular weight compounds such as metal or metal-free phthalocyanine compounds such as tris (8-hydroxyquinolinolate) aluminum (Alq ₃ ), factory (2-phenylpyridine) iridium (Ir (ppy) ₃ ) Polymers such as oxadiazole polymers, triazole polymers, carbazole polymers The light L which has the target luminescent color can be obtained combining these 1 type (s) or 2 or more types.

  In the present embodiment, each of the light emitting elements 72 is configured to emit red light. Here, examples of the light-emitting layer 727 that emits red light include (4-dicyanomethylene) -2-methyl-6- (paradimethylaminostyryl) -4H-pyran (DCM), Nile red, and the like. Each light emitting element 72 is not limited to be configured to emit red light, and may be configured to emit monochromatic light of other colors or white light. Thus, in the organic EL element, the light L emitted from the light emitting layer 727 can be appropriately set to monochromatic light of an arbitrary color according to the constituent material of the light emitting layer 727.

However, the spectral sensitivity characteristics of a photosensitive drum generally used in an electrophotographic process are set to have a peak in the region from red to the near infrared, which is the emission wavelength of a semiconductor laser. It is preferable to use materials.
The protective layer 725 is provided so as to cover the layers 722, 723, and 724 constituting the light emitting element 72. The protective layer 725 has a function of hermetically sealing the layers 722, 723, and 724 included in the light emitting element 72 and blocking oxygen and moisture. By providing the protective layer 725, the reliability of the light emitting element 72 can be improved, and effects such as prevention of deterioration and deterioration can be obtained.

As a constituent material of the protective layer 725, for example, a constituent material similar to that of the substrate 71 can be used.
When each light emitting element 72 is comprised by such an organic EL element, the space | interval (pitch) between light emitting elements 72 can be set comparatively small. Thereby, when an image is recorded on the recording medium P, the recording density on the recording medium P becomes relatively high. Therefore, the recording medium P carrying a clearer image can be obtained.

An optical path adjusting member such as a reflector for preventing the light L from spreading may be provided on the outer peripheral side of each light emitting element 72.
The light emitting element 72 is not limited to an element having a bottom emission structure, and may be an element having a top emission structure in which light L from the light emitting layer 727 is extracted and used on the cathode 724 side.

Further, the materials or layer configurations of the organic EL elements described above are representative examples, and the effects and advantages of the present invention can be obtained in the same manner even with other materials and layer configurations.
Each of the light emitting elements 72 is electrically connected to a control circuit 192 via a drive circuit 191 as shown in FIG.
The drive circuit 191 is for driving each light emitting element 72.

  The drive circuit 191 is preferably installed so as to be covered by the support member 6 described above. That is, the support member 6 is preferably disposed so as to cover the drive circuit 191 as well. Thereby, it is possible to prevent an adverse electromagnetic effect such as noise from being mixed in from the wiring between each light emitting element 72 and the drive circuit 191, and to perform highly accurate exposure processing stably. Further, by providing the drive circuit 191 inside the support member 6, the length of the wiring between each light emitting element 72 and the drive circuit 191 can be shortened. Therefore, also in this respect, it is possible to effectively prevent noise from being mixed in from the wiring between the light emitting elements 72 and the drive circuit 191.

Note that the driver circuit 191 may be formed on the substrate 71 together with the plurality of light emitting elements 72, or may be formed on a substrate different from the substrate 71. Further, the drive circuit 191 may be formed entirely on the substrate 71 together with the plurality of light emitting elements 72, or a part of the drive circuit 191 may be formed on the substrate 71 together with the plurality of light emitting elements 72, with the remainder being the substrate. It may be formed on a substrate different from 71.
A control circuit 192 is electrically connected to such a drive circuit 191.
The control circuit 192 controls the operation of the drive circuit 191. The control circuit 192 controls the operation of the drive circuit 191 based on a signal from a main body controller 18 to be described later and information stored in the memory 193.

  The control circuit 192 is preferably installed so as to be covered by the support member 6 described above. That is, the support member 6 is preferably arranged so as to cover the control circuit 192 as well. As a result, it is possible to prevent electromagnetic adverse effects such as noise from the wiring between the drive circuit 191 and the control circuit 192, and to perform highly accurate exposure processing stably. Further, by providing the control circuit 192 inside the support member 6, the length of the wiring between the drive circuit 191 and the control circuit 192 can be shortened. Therefore, in this respect as well, it is possible to effectively prevent noise from entering from the wiring between the drive circuit 191 and the control circuit 192.

Such a control circuit 192 is electrically connected to a main body controller 18 provided in the main body of the image forming apparatus 1.
The main body controller 18 has a function of transmitting a control signal for driving control of each light emitting element 72 to the control circuit 192. The main body controller 18 also has a function of controlling each unit of the image forming apparatus 1.
The driving of each light emitting element 72 is controlled by such a control system.

Further, as shown in FIG. 3, the cover member 73 provided on the one surface side of the substrate 71 together with the plurality of light emitting elements 72 as described above has a recess 731, and the periphery of the recess 731 is the substrate 71. It is joined to. A plurality of light emitting elements 72 are accommodated in the recess 731. Thereby, the cover member 73 covers the plurality of light emitting elements 72.
The cover member 73 prevents foreign matter from adhering to each light emitting element 72 and the like. Further, the cover member 73 has a flat surface on the side opposite to the recess 731.

Although it does not specifically limit as a constituent material of this cover member 73, A glass material is used suitably. By comprising both the cover member 73 and the board | substrate 71 with a glass material, malfunctions, such as a deformation | transformation by the linear expansion coefficient difference between these, damage, can be prevented.
In this way, the plurality of light emitting elements 72 and the cover member 73 are bonded to one surface of the substrate 71. The lens array 16 is optically bonded to the other surface of the substrate 71 via the spacer 171. ing.

The lens array 16 is provided on the light L emission side of the light emitting substrate unit 7. This lens array 16 has a large number of gradient index rod lenses 161 arranged so as to be stacked in two rows in the main scanning direction.
Each rod lens 161 is installed such that its optical axis is in the thickness direction of the substrate 71. Each rod lens 161 is made of, for example, a resin material and / or a glass material.

The spacer 171 defines the distance between each light emitting element 72 and the lens array 16. The spacer 171 has a plate shape and is made of, for example, a resin material and / or a glass material. By providing such a spacer 171, the distance between each light emitting element 72 and the lens array 16 can be adjusted according to the thickness of the spacer 171. As a result, highly accurate exposure processing can be realized with a relatively simple configuration.
In particular, the spacer 171 is a light-transmitting substrate and is optically bonded to the lens array 16 and supports the lens array 16. Thereby, the distance between each light emitting element 72 and the lens array 16 can be prescribed | regulated easily and correctly.

In addition, since the spacer 171 has a plate shape, the distance between each light emitting element 72 and the lens array 16 and the distance between the substrate 71 and the support member 6 can be accurately and stably. Can be prescribed.
According to the line head 13 as described above, while suppressing the cost of the support member 6, unintentional electromagnetic influence between each light emitting element 72 and the outside is prevented, and high-precision exposure processing is stably performed. It can be carried out. Therefore, according to the image forming apparatus 1 including such a line head 13, an inexpensive and high-quality image can be obtained.

<Second Embodiment>
Next, a second embodiment of the present invention will be described.
FIG. 6 is a cross-sectional view of a line head according to the second embodiment of the present invention.
Hereinafter, the line head according to the second embodiment will be described focusing on the differences from the first embodiment described above, and description of similar matters will be omitted.
The line head 13A of this embodiment is the same as the line head 13 of the first embodiment described above except that the spacer is omitted and a cover for light shielding is provided.

In the present embodiment, the substrate 71 is bonded to the support portion 61 of the support member 6. The lens array 16 is supported by a cover 172.
The cover 172 is provided so as to cover the support portion 61 of the support member 6 and has a light shielding property. Therefore, the cover 172 has a function of shielding light that has not entered the lens array 16 from each light emitting element 72.

  Even with the line head 13A as described above, the same effects as those of the line head 13 of the first embodiment described above can be exhibited. That is, while suppressing the cost of the support member 6, unintentional electromagnetic influence between each light emitting element 72 and the outside can be prevented, and high-precision exposure processing can be performed stably. Therefore, according to the image forming apparatus 1 including such a line head 13, an inexpensive and high-quality image can be obtained.

The line head and the image forming apparatus of the present invention have been described above with respect to the illustrated embodiment. However, the present invention is not limited to this, and each part constituting the line head and the image forming apparatus has the same function. It can be replaced with any configuration that can be exhibited. Moreover, arbitrary components may be added.
The lens array is not limited to a plurality of lenses arranged in a matrix of 2 rows and n columns, and may be arranged in a matrix of 3 rows and n columns, 4 rows and n columns, for example.

Also, a microlens array in which a large number of microlenses are arranged can be used as the lens array.
In the above-described embodiment, for convenience of explanation, the light emitting elements are arranged in 1 row and n columns. However, the present invention is not limited to this, and the light emitting elements are 2 rows n columns, 3 rows n columns, and the like. May be arranged in a matrix.
Moreover, each light emitting element is not limited to being comprised by the organic EL element, respectively, For example, you may be comprised by the light emitting diode (LED).

FIG. 1 is a schematic diagram showing the overall configuration of the image forming apparatus according to the first embodiment of the present invention. FIG. 2 is a partial cross-sectional perspective view of a line head provided in the image forming apparatus shown in FIG. 1. It is a cross-sectional view of the line head shown in FIG. It is sectional drawing which shows schematic structure of the light emitting element with which the line head shown in FIG. 2 was equipped. It is a block diagram which shows the structure of the control system of the line head shown in FIG. It is a cross section of the line head concerning 2nd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 6 ... Support member 61 ... Support part 62 ... Leg part 611 ... Recessed part 7 ... Light emitting board unit 71 ... Substrate 72 ... Light emitting element 73 ... Cover member 722 ... Anode 723 ... Organic semiconductor layer 724 ... Cathode 725 ... Protection Layer 726 ... Hole transport layer 727 ... Light emitting layer 728 ... Electron transport layer 731 ... Opening 10 ... Image forming unit 10C, 10K, 10M, 10Y ... Image forming station 11 ... Photosensitive drum (photoconductor) 111 ... Light receiving surface 12 ... Charging Units 13, 13A ... line head (exposure unit) 14 ... developing device 15 ... cleaning unit 151 ... cleaning blade 16 ... lens array 161 ... rod lens 171 ... spacer 172 ... cover 20 ... transfer unit 21 ... intermediate transfer belt 22 ... primary transfer Roller 23 ... Drive b La 24 ... Follower roller 25 ... Secondary transfer roller 26 ... Cleaning unit 261 ... Cleaning blade 30 ... Fixing unit 301 ... Fixing roller 302 ... Pressure roller 40 ... Conveying mechanism 41 ... Registration roller pair 42, 43, 44 ... Conveying roller pair DESCRIPTION OF SYMBOLS 50 ... Paper feed unit 51 ... Paper feed cassette 52 ... Pickup roller P ... Recording medium Q ... Spot (latent image) L ... Light

Claims (8)

A support member;
A substrate supported by the support member, and a light emitting substrate unit including a light emitting element disposed on the substrate,
The line head according to claim 1, wherein the support member is formed by bending a metal plate so as to cover the light emitting substrate unit while allowing the light from the light emitting element to be emitted from the light emitting substrate unit.   The line head according to claim 1, wherein the support member includes a support portion that supports the substrate and a leg portion that is perpendicular or substantially perpendicular to the support portion.   The drive circuit for driving the light emitting element and a control circuit for controlling the operation of the drive circuit, and the support member is disposed so as to cover the drive circuit. 2. The line head according to 2.   The line head according to claim 3, wherein the support member is disposed so as to cover the control circuit.   5. The lens array according to claim 1, further comprising: a lens array provided on a light emission side of the light emitting substrate unit, wherein the support member shields light that has not entered the lens array from the light emitting element. Line head as described in.   The line head according to claim 5, wherein the substrate is bonded to the support member via a spacer.   The line head according to claim 6, wherein the spacer is a light-transmitting substrate, is optically bonded to the lens array, and supports the lens array. A photoreceptor,
A line head, and
The line head is
A support member;
A light-emitting substrate unit including a substrate supported by the support member and a light-emitting element disposed on the substrate;
The support member is formed by bending a metal plate so as to cover the light emitting substrate unit while allowing the light from each light emitting element to be emitted from the light emitting substrate unit. apparatus.

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