JP4511012B2 - Optical printer head - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical printer head .
[0002]
[Prior art]
Conventionally, an optical printer head, such as a LED array head is used as an exposure unit such as an electrophotographic printer.
[0003]
As such a conventional optical printer head, as was shown in Figure 4 for example, a housing 14 made of resin rod lens array 13 is attached, and a plurality of LED array chips 12 and the driver IC15 are mounted on the circuit board 11, it is known a structure that was placed as a rod lens array 13 is positioned directly above the LED array chips 12, are provided on the upper surface of the L ED array chip 12 A number of light emitting elements 12a are selectively made to emit light individually as the driver IC 15 is driven, and the emitted light is irradiated to an external photoconductor P through the rod lens array 13 so that a predetermined latent image is applied to the photoconductor P. It functions as an optical printer head.
[0004]
Then, the latent image formed on the photosensitive member P is then become a toner image through development of the process, the transfer of the toner image to the recording sheet, by fixing, and the predetermined image is recorded on the recording paper Become.
[0005]
[Problems to be solved by the invention]
However, when a latent image is formed on the photosensitive member P using the above-described conventional optical printer head, electromagnetic waves emitted from other devices incorporated in the electrophotographic printer are transmitted through the housing 14 and the electronic circuit of the driver IC 15 The noise may enter the driver IC 15 and cause the driver IC 15 to malfunction. In this case, it is impossible to cause the light emitting element 12a to emit light accurately in accordance with the image data, and a desired latent image cannot be obtained.
[0006]
Therefore , in order to eliminate the above-described drawbacks, it is conceivable to shield the noise by forming the housing 14 of the optical printer head from metal and holding it at the ground potential.
[0007]
However, such an optical printer head is disposed in the vicinity of a charger for applying a charge to the photosensitive member P in an electrophotographic printer or the like. Therefore, the housing 14 is made of a metal as described above. If formed, discharge also occurs between the charger and the housing 14, and in this case, a large current flows to the driver IC 15 through the housing 14 and the driver IC 15 may be destroyed.
[0008]
The present invention has been devised in view of the above drawbacks, and an object of the present invention is to provide an optical printer head capable of effectively preventing malfunction and destruction of a driver IC and always operating accurately. .
[0009]
[Means for Solving the Problems]
An optical printer head according to the present invention includes a circuit board on which a ground wiring is provided on an upper surface, a light emitting element array chip mounted on the circuit board, and a driver IC mounted on the circuit board. A housing that houses the light emitting element array chip and the driver IC between the circuit board and a rod lens array that is held in the housing and is located on the light emitting element array chip. A metal film that is attached to at least a region of the inner surface of the housing facing the driver IC, and a part of the metal film is led to the lower surface of the housing, and the housing has a specific resistance of 1 ×. consist ^{10 1 3 ~ 1 × 10 17} Ω · cm of the resin, the metal film and the driver IC is being electrically connected to said ground line .
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Figure 1 is an exploded perspective view of the optical printer head according to an embodiment of the present invention, FIG. 2 is a sectional view of an optical printer head in FIG. 1, 1 is a circuit board, 1c is ground wiring, 2 is a LED array chip as a light emitting element array chips, 3 is a driver IC, 4 is a rod lens array, 5 is a housing, 5b are septum 6 is a metal film.
[0011]
Circuitry substrate 1, a glass cloth epoxy resin, glass, a ceramic or the like insulating top to double several circuit wiring 1b of the substrate 1a, and the deposited is not a structure to 1c, the upper surface LED array chip 2, A driver IC 3 or the like is mounted and functions as a support base material that supports these.
[0012]
The circuit wirings 1b and 1c of the circuit board 1 are for supplying power and electric signals from the outside to the LED array chip 2 and the driver IC 3, and are made of a conductive material containing a metal such as silver or copper . It formed a predetermined pattern for forming Suyo.
[0013]
Incidentally, circuits substrate 1, for example, when the insulating substrate 1a is made of glass cloth epoxy resin, first, cured impregnated with liquid epoxy resin on a glass fabric substrate formed using glass strands, this predetermined An insulating substrate 1a is formed by cutting and processing into a rectangular shape, and a conductive paste is printed and applied in a predetermined pattern on the upper surface of the obtained insulating substrate 1a by a conventionally known screen printing or the like, and this is baked at a high temperature. It is manufactured by forming the wiring 1b.
[0014]
On the upper surface of the circuit board 1, a plurality of LED array chips 2, and the driver IC3 is mounted.
[0015]
L ED array chip 2, a density of the upper surface e.g. 600dpi (dot per inch) has a plurality of light-emitting elements 2a which are arranged linearly in the main scanning direction, the top surface of the circuit board 1 in such a light-emitting element 2a When power supply power is applied through the circuit wirings 1b, 1c, etc., the light emitting element 2a emits light with a predetermined luminance.
[0016]
As such a light-emitting element 2a, for example, a GaAlAs-based or GaAsP-based light-emitting diode element is preferably used, and the LED array chip 2 having such a light-emitting element 2a is manufactured by adopting a conventionally well-known semiconductor manufacturing technique. The
[0017]
On the other hand, drivers IC3, the output transistor on a main surface, an electronic circuit such as a shift register becomes to high density integration, the action of control based on image data from an external light emission of the light emitting element 2a described above Do it.
[0018]
Incidentally, drivers IC3, like the LED array chip 2 is manufactured by employing a conventionally known semiconductor fabrication techniques.
[0019]
Furthermore, LED array chip 2 and the driver IC3 is placed at a predetermined position on the upper surface of the circuit board 1, after being fixed to a terminal provided in each of the upper surface, the upper surface of the circuit wiring 1b of the circuit board 1, 1c by bonding the preparative connection member of the bonding wire or the like and is mounted on a circuit board 1.
[0020]
Then, on a circuit board 1 mounted with L ED array chip 2 and the driver IC3, the housing 5 is placed.
[0021]
Housings 5, the specific resistance is ^{1 × 10 1 3 ~ 1 ×} 10 17 Ω · cm, the light transmittance of 20% or less of the resin, for example, liquid crystal polymers, polyphenylene sulfide, made of polycarbonate or the like, provided in the upper portion It holds the rod lens array 4 within the frame 5a which have the LED array chips 2 and the driver IC3 an action to be accommodated in between the circuit board 1.
[0022]
Further , a partition wall 5b made of the same resin as that of the housing body is provided on the inner surface of the housing 5.
[0023]
Further, the partition wall 5b is for separating the accommodating area and receiving area of the LED array chips 2 driver IC3, a resin material such as liquid crystal polymer housing 5 provided integrally with the lower end circuit board 1 is reached.
[0024]
Incidentally, housings 5 is fabricated by employing a conventionally known injection molding method or the like, after which the housing 5 obtained was positioned at a predetermined position on the circuit board 1, by fixing both by screwing It is attached to a predetermined position on the circuit board 1 by.
[0025]
The rod lens array 4 held in the housing 5 is an erecting equal-magnification lens, and a large number of rod-shaped lenses arranged in a straight line or a large number of rod-shaped lenses arranged in a staggered pattern are framed. It has a structure arranged in the body.
[0026]
Rod lens array 4 is held on the light-emitting surface of the LED array chips 2, the light emitting element 2a of LED array chip 2 emits light, irradiation of these light to the outside of the photosensitive member P, the action for imaging Do it.
[0027]
Rod lens array 4, after having been inserted into the frame 5a of the housing 5 is fixed to the frame 5a of the housing 5 by an adhesive mainly composed of epoxy resin or the like.
[0028]
A metal film 6 is attached to at least a region facing the driver IC 3 in the inner surface of the housing 5 described above, specifically, a housing region of the driver IC 3 partitioned by the partition wall 5b.
[0029]
Kim Shokumaku 6, together with the part is derived on the lower surface of the housing 5, the circuit wiring on the circuit board 1 via the brazing material 7 such as solder at the conductor out portion electrically connected to the (ground line 1c) Thus, when the optical printer head is used, it is always held at the ground potential GND.
[0030]
For this reason, when a latent image is formed on the photosensitive member P using an optical printer head, electromagnetic waves generated by other devices incorporated in the electrophotographic printer are well shielded by the metal film 6 held at the ground potential GND. Thus, it is possible to effectively prevent noise from entering the electronic circuit of the driver IC 3. As a result, the optical printer head can always be operated accurately.
[0031]
Also in this case, since the housings 5 specific resistance is formed of a resin of ^{1 × 10 1 3 ~ 1 ×} 10 17 Ω · cm, electric discharge may occur between an external charger and the housing 5, It is possible to effectively prevent the occurrence of discharge between the charger and the metal film 6 attached to the inner surface of the housing 5 , and to eliminate the destruction of the driver IC 3 due to such discharge. Can do.
[0032]
Moreover, gold Shokumaku 6, part is derived on the lower surface of the housing 5, since it is electrically connected to a ground wiring 1c on the circuit board 1 by conductor out unit, without using a jumper wire or the like The metal film 6 can be connected to the ground potential GND very easily, and it becomes possible to effectively prevent the configuration from becoming complicated and the mounting work from becoming complicated.
[0033]
Furthermore , since the metal film 6 is attached only to the housing area of the driver IC 3 and the optical path between the metal film 6 and the LED array chip 2 is blocked by the partition wall 5b, the light from the LED array chip 2 is metal. There is no irregular reflection on the surface of the film 6, and an unnecessary latent image is not formed on the photoreceptor P.
[0034]
Incidentally, the gold Shokumaku 6, gold (Au), or is on the interior surface of the housing 5 by nickel (Ni) electroless plating of a metal such as a well known prior art such as, or copper foil, aluminum foil adhesive by or to adhere to the inner surface of the housing 5 by, it provided within the housing 5.
[0035]
Thus , the above-described optical printer head selectively causes the light emitting elements 2a of the LED array chip 2 to emit light individually as the driver IC 3 is driven, and the emitted light passes through the rod lens array 4 to the external photoconductor. By irradiating and forming an image on P, a predetermined latent image is formed on the photoreceptor P, thereby functioning as an optical printer head.
[0036]
The latent image formed on the photoreceptor P is then converted into a toner image through a development process, and a predetermined image is recorded on the recording paper by transferring and fixing the toner image on the recording paper. .
[0037]
In addition, this invention is not limited to the above-mentioned form, A various change, improvement, etc. are possible in the range which does not deviate from the summary of this invention.
[0038]
For example , in the above-described embodiment, the partition 5b is provided on the inner surface of the housing 5, and the partition 5b separates the storage area of the LED array chip 2 from the storage area of the driver IC 3. 3 (see FIG. 3), the electromagnetic wave from the outside can be well shielded by the metal film 6, and discharge is generated between the housing 5 and the metal film 6 and the charger. It can be effectively prevented.
[0039]
In the above-described embodiment, the LED array head has been described as an example. However, the present invention can also be applied to other optical printer heads such as an EL head, a plasma dot head, a liquid crystal shutter head, a fluorescent head, and a PLZT. .
[0040]
【The invention's effect】
According to the optical printer head of the present invention, the light emitting element array chip, a housing the driver IC is mounted on a circuit board mounted, specific resistance of ^{1 × 10 1 3 ~ 1 ×} 10 17 Ω · cm Since a metal film that is held at the ground potential is deposited on the inner surface of the housing facing the driver IC, a latent image is formed on the photoconductor using an optical printer head. When forming, electromagnetic waves emitted by other devices incorporated in the electrophotographic printer are well shielded by the metal film held at the ground potential, and it is effective for noise to enter the electronic circuit of the driver IC. Can be prevented. As a result, the optical printer head can always be operated accurately.
[0041]
Further, according to the optical printer head of the present invention, since the housings are specific resistance is formed of a resin of ^{1 × 10 1 3 ~ 1 ×} 10 17 Ω · cm, charging device - discharge between the housing of course In other words, the discharge between the charger and the metal film deposited on the inner surface of the housing is also effectively prevented, thereby making it possible to eliminate the destruction of the driver IC.
[0042]
Accordingly, it is possible to form an accurate latent image corresponding to the image data on the surface of the photoconductor.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of an optical printer head according to an embodiment of the present invention.
2 is a cross-sectional view of the optical printer head of FIG.
FIG. 3 is a cross-sectional view of an optical printer head according to another embodiment of the present invention.
FIG. 4 is a cross-sectional view of a conventional optical printer head.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Circuit board, 1c ... Ground wiring, 2 ... Light emitting element array chip (LED array chip), 3 ... Driver IC, 4 ... Rod lens array, 5 ... Housing, 5b ... Partition walls, 6 ... Metal films

Claims (2)

A circuit board provided with ground wiring on the upper surface;
A light emitting element array chip mounted on the circuit board;
A driver IC mounted on the circuit board;
A housing that houses the light emitting element array chip and the driver IC between the circuit board,
A rod lens array positioned on the light emitting element array chip, held in the housing;
A metal film that is attached to at least a region of the inner surface of the housing that faces the driver IC and that is partially led to the lower surface of the housing;
The housing resistivity consists ^{1 × 10 1 3 ~ 1 ×} 10 17 Ω · cm of the resin,
The optical printer head , wherein the metal film and the driver IC are electrically connected to the ground wiring . 2. The optical printer head according to claim 1, wherein a partition that separates the housing area of the driver IC and the housing area of the light emitting element array chip is provided on an inner surface of the housing.

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