JP2007106009A - Method for manufacturing exposure module, exposure module and imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an exposure module which can reduce the dispersion of light-emitting element characteristics among the elements without causing a contamination, and an exposure module and an imaging device. <P>SOLUTION: The cathode side of the light-emitting elements 11a, 11b, etc. are each connected with a grounding wire 24 through resistance elements 22a, 22b, etc. and bypass wirings 23a, 23b, etc. The bypass wirings 23a, 23b, etc. are conducting wirings partially connected side by side with the resistance elements 22a and 22b, etc. Thus, the load resistance value of the resistance elements 22a, 22b, etc. acting on the light-emitting elements 11a, 11b, etc. can be substantially adjusted by the connection relationship. In this case, the bypass wirings 23a, 23b, etc. are formed using a liquid droplet discharging process, after detecting the brightness characteristics of the individual light-emitting elements 11a, 11b, etc. are detected. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to an exposure module including a light emitting element array, a manufacturing method thereof, and an image forming apparatus.

2. Description of the Related Art Image forming apparatuses that form a latent image on a photoreceptor using an exposure unit and visualize the latent image using toner or the like are now widely used as copying machines and printing machines. As an exposure method for forming a latent image, a type in which light from a light source is reflected by a polygon mirror and scanning is performed, or a type in which line scanning is performed by a plurality of light emitting elements (light emitting element array) arranged in a line, etc. There is.

The above-described method using the light emitting element array is advantageous for simplification (downsizing) of the apparatus configuration because there is no moving part. However, since a plurality of light emitting elements are used as light sources, the characteristics (brightness) of the light emitting elements Variation is a problem. Therefore, a method of correcting such inter-element variation by driving the light emitting element array, measuring the luminance of each light emitting element, and performing partial electrode removal for each light emitting element based on the measured value is disclosed in Patent Literature 1 is disclosed.

JP-A-3-363264

However, in the above-described method, there is a problem of yield reduction due to contamination that occurs during partial removal of electrodes.

The present invention has been made to solve the above-described problems, and can provide a method for manufacturing an exposure module, an exposure module, and an image that can reduce variation in light-emitting element characteristics between elements without causing contamination. An object is to provide a forming apparatus.

The present invention is a method of manufacturing an exposure module including a circuit in which a plurality of light emitting elements are connected in parallel, and includes a resistance element connected in series to each of the plurality of light emitting elements, and forming the circuit A forming step; a characteristic detecting step for detecting a light emitting characteristic for each of the plurality of light emitting elements; a load adjusting step for adjusting a load resistance value acting on the light emitting element based on a detection result in the characteristic detecting step; The load adjusting step is performed by partially connecting a bypass wiring to the resistance element in parallel.

According to the method for manufacturing an exposure module of the present invention, the additional resistance value acting on the light emitting element can be adjusted by additionally forming a bypass wiring for each light emitting element, so that light emission can be performed without causing contamination. Variation in characteristics between elements can be reduced.

Preferably, in the exposure module manufacturing method, the load adjusting step is performed using a droplet discharge method.
According to the method for manufacturing an exposure module of the present invention, the above-described additional resistance value can be adjusted efficiently using the droplet discharge method.

The present invention is an exposure module including a circuit in which a plurality of light emitting elements are connected in parallel, and the circuit includes a resistance element connected in series to each of the plurality of light emitting elements, and a part of the resistance element. And bypass wiring connected in parallel.

According to the exposure module of the present invention, the additional resistance value acting on the light emitting element can be adjusted by additionally forming a bypass wiring for each light emitting element, so that the emission characteristics can be reduced without causing contamination. Variations between elements can be reduced.

Preferably, in the exposure module, a connection relationship between the bypass wiring and the resistance element is individually set for each corresponding light emitting element.
In the exposure module of the present invention, since the connection relationship between the bypass wiring and the resistance element is set for each light emitting element, uniform light can be emitted from each light emitting element.

  An image forming apparatus according to the present invention includes the exposure module.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings.
The embodiment described below is a preferred specific example of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention is particularly limited in the following description. Unless otherwise stated, the present invention is not limited to these forms.

(Configuration of image forming apparatus)
First, the overall configuration of the image forming apparatus according to the present invention will be described with reference to FIG.
FIG. 1 is a cross-sectional view illustrating an internal configuration of an example of an image forming apparatus.

In FIG. 1, an image forming apparatus 100 includes a driving roller 51, a driven roller 52, a tension roller 53, and an intermediate transfer belt 50 that is circulated and driven in the direction indicated by the arrow (counterclockwise) by these rollers 51, 52, and 53. It is equipped with. Further, the image forming apparatus 100 has four photosensitive drums 41 </ b> K having the same configuration and disposed at a predetermined interval so as to face the intermediate transfer belt 50.
, 41C, 41M, 41Y. Photosensitive drums 41K, 41C, 41M, 41Y
Is driven to rotate in the direction indicated by the arrow (clockwise) in synchronization with the drive of the intermediate transfer belt 50.

The symbols K, C, M, and Y added to the reference numerals in the above-described figures and drawings mean black, cyan, magenta, and yellow, respectively, and the elements (parts) of the reference numerals that have K, C, M, and Y added thereto. Represents elements provided corresponding to the respective colors. Each color element has the same configuration,
In the following, in order to avoid complexity of description, the description of each element is omitted by omitting K, C, M, and Y.

The photosensitive drum 41 is synchronized with the driving of the intermediate transfer belt 50 in the direction indicated by the arrow (clockwise).
It is driven to rotate. Around the photosensitive drum 41, a charging means (corona charger) 42 for uniformly charging the photosensitive surface (outer peripheral surface) of the photosensitive drum 41, and the photosensitive surface are lined in synchronization with the rotation of the photosensitive drum 41. An exposure head 10 is provided as an exposure module for scanning. Here, the light emission energy peak wavelength of the exposure head 10 and the sensitivity peak wavelength of the photosensitive member surface are set to substantially coincide with each other, and a latent image (electrostatic image) is formed on the photosensitive member surface by the scanning by the exposure head 10. It is formed.

In addition, around each photosensitive drum 41, toner is applied to the latent image on the photosensitive member surface so that a visible image (
A developing device 44 for forming a toner image), a primary transfer roller 45 for transferring the toner image to the intermediate transfer belt 50, and a cleaning device 46 for removing the toner remaining on the surface of the photoreceptor after the primary transfer. Yes.

The developing device 44 conveys the toner to the developing roller with, for example, a supply roller, regulates the film thickness of the developer attached to the surface of the developing roller with a regulating blade, and brings the developing roller into contact with the photoreceptor surface of the photoreceptor drum 41. A developer is attached in accordance with the potential level of the photosensitive surface.

Each toner image formed corresponding to each of black, cyan, magenta, and yellow is sequentially primary-transferred onto the intermediate transfer belt 50 by the primary transfer bias applied to the primary transfer roller 45, and on the intermediate transfer belt 50. The toner images that are sequentially superimposed and become full color are secondarily transferred to the recording medium P such as paper by the secondary transfer roller 66, and are fixed on the recording medium P through the fixing unit 61. As a result, the paper is discharged onto a paper discharge tray 68 formed in the upper part of the apparatus.

For the fixing unit 61, a heat roll type using a heating roller, a flash type using light irradiation, or the like is used. In the case of a flash system, an irradiation unit having the same configuration as that of an exposure head 10 to be described later can be adopted.

In the figure, reference numeral 63 denotes a paper feeding cassette in which a large number of recording media P are stacked and held, 64 denotes a pickup roller for feeding the recording media P from the paper feeding cassette 63 one by one, and 65 denotes a secondary transfer roller 66. A pair of gate rollers for defining the supply timing of the recording medium P to the secondary transfer portion of
Reference numeral 6 denotes a secondary transfer roller as a secondary transfer unit that forms a secondary transfer portion with the intermediate transfer belt 50, and 67 denotes cleaning that removes toner remaining on the surface of the intermediate transfer belt 50 after the secondary transfer. A cleaning blade as a means.

(Configuration of exposure head)
Next, the configuration of the exposure head will be described with reference to FIGS.
FIG. 2 is a circuit diagram showing the electrical configuration of the exposure head. FIG. 3 is a partial plan view showing a planar structure of the resistance element and the bypass wiring.

2, the exposure head 10 includes light emitting elements 11a, 11b,... Arranged in a line along the rotation axis direction of the photosensitive drum 41 (see FIG. 1). Light emitting elements 11a and 11
Each of b ... uses a known organic EL element, and has a structure in which an anode electrode, a hole transport layer, an organic EL material layer, an electron transport layer, and a cathode electrode are laminated.

The anode side of the light emitting elements 11a, 11b... Is connected to the drain terminals of the drive switches 13a, 13b. Furthermore, the drive switch 1
The source terminals 3a, 13b... Are connected to the source line 14 to which the drive voltage VD is supplied. Further, the gate terminals of the drive switches 13a, 13b... Are connected to the control circuit 15.

Control circuit 15 is connected to shift register 16 connected to signal line 19 and signal line 20, latch circuit 17 connected to the output terminal of shift register 16 and signal line 21, and the output terminal of latch circuit 17. And a decoder circuit 18. Here, the signal line 19
Is supplied with the clock signal CLK, the signal line 20 with the data signal DAT, and the signal line 21 with the latch signal LAT.

The data signal DAT is a serial data signal composed of drive gradation values (multivalue) for each light emitting element 11a, 11b,. The data signal DAT transferred to the shift register 16 in synchronization with the clock signal CLK is latched at a timing corresponding to the recording cycle, and is decoded by the decoder circuit 18 into a pulse wave corresponding to each gradation value. And each drive switch 13a,
The pulse voltage is applied to the gate terminals 13b, so that the drive voltage VD is supplied to the light emitting elements 11a, 11b, and light is emitted. The pulse wave is, for example, a rectangular wave in which the time component becomes longer as the gradation value increases, and gradation control is performed based on the difference in voltage supply time within one recording cycle.

The cathode side of the light emitting elements 11a, 11b... Is connected to the ground line 24 via the resistance elements 22a, 22b and bypass wirings 23a, 23b. Here, the bypass wirings 23a, 23b... Are conductive wirings partially connected in parallel with the resistance elements 22a, 22b..., And the resistance elements 22a, 2 acting on the light emitting elements 11a, 11b.
The substantial load resistance value of 2b... Is adjusted. The resistance elements 22a and 22
.. and the bypass wirings 23a, 23b,... are connected to the corresponding light emitting elements 11a, 11b.
Each is set individually.

As shown in FIG. 3, the resistance elements 22a, 22b... Are made of a high resistance material formed between the electrodes 24a, 24b... Extending from the ground line 24 and the electrodes 25a, 25b. A membrane (illustrated by hatching).

The bypass wirings 23a, 23b... Are conductive material films that are formed so as to overlap a part of the resistance elements 22a, 22b. The overlapping regions (broken line regions) of the resistance elements 22a, 22b, etc. with the bypass wirings 23a, 23b substantially lose the function as the resistance component, and thus act on the light emitting elements 11a, 11b,. The substantial load resistance value to be determined is determined according to the degree of the overlapping region.

As described above, by setting the corresponding load resistance value for each of the light emitting elements 11a, 11b,..., The inter-element variation in characteristics is compensated. It is possible to emit light of uniform brightness from 11b.

(Configuration of droplet discharge device)
Next, a droplet discharge apparatus used in the droplet discharge method will be described with reference to FIG. FIG. 4 is a schematic diagram illustrating an example of the configuration of the droplet discharge device.

In FIG. 4, the droplet discharge device 200 includes a discharge head 201 having a plurality of nozzles 212 arranged on one surface, and a mounting table 203 for mounting a substrate 202 at a position facing the discharge head 201.
And. Further, a scanning unit 204 that moves (scans) the ejection head 201 vertically and horizontally while maintaining a distance from the substrate 202, a functional liquid supply unit 205 that supplies functional liquid to the ejection head 201, and ejection control of the ejection head 201. And a discharge control means 206 for performing the above.

The discharge head 201 is formed with a plurality of minute flow paths that branch into a pressure chamber (cavity) 211 and a nozzle 212. One surface of the outer wall of the pressure chamber 211 can be deformed by the piezoelectric element 210, and by generating a pressure in the pressure chamber 211 by a drive signal from the discharge control means 206, the droplet 213 is discharged from the nozzle 212.
Is discharged. In addition to the electromechanical system as in this example, the discharge technique includes a so-called thermal system in which an electric signal is converted into heat to generate pressure.

In the above configuration, by performing ejection control for each nozzle 212 in synchronization with the scanning of the ejection head 201, it is possible to dispose the functional liquid in a desired pattern on the substrate 202. The droplet discharge device 200 can also be configured to discharge a plurality of types of functional liquids during one scan.

(Exposure head manufacturing method)
Next, an exposure head manufacturing method will be described with reference to FIGS. 2, 3, 5, and 6. FIG.
These are the flowcharts which show the manufacturing process of an exposure head. FIG. 6 is a partial plan view of a circuit in a manufacturing process.

In the first step, the light emitting elements 11a, 11b,...
The resistance elements 22a, 22b,..., The drive switches 13a, 13b..., The control circuit 15, and various wirings connecting them are formed on the substrate (circuit formation step S1 in FIG. 5). At this time, the resistance elements 22a, 22b... On the substrate are formed as high resistance material films (shown by hatching) defined by uniform dimensions, as shown in FIG. have.

Next, a drive signal is supplied to the circuit formed in step S1 to drive each of the light emitting elements 11a, 11b..., And a light emission characteristic (luminance characteristic) is detected for each element using a luminance sensor or the like (FIG. 5
Characteristic detection step S2).

Next, as shown in FIG. 6B, the conductive functional liquid L is arranged in a pattern so as to partially overlap the resistance elements 22a, 22b... Using the droplet discharge method (step S3 in FIG. 5). Further, by firing the conductive functional liquid L in an electric furnace or the like, as shown in FIG.
3b... Are formed (step S4 in FIG. 5). As a result, the load resistance value acting on the light emitting elements 11a, 11b... Decreases according to the amount of overlap between the resistance elements 22a, 22b. That is, step S3 and step S4 constitute a load adjustment step in the present invention.

In FIG. 6B, the overlapping amount of the resistance elements 22a, 22b... And the conductive functional liquid L is set based on the luminance characteristic information acquired in the previous step S2. That is, the amount of overlap between the resistance elements 22a, 22b... And the conductive functional liquid L is set so that the difference between the detected value of the luminance characteristic and the predetermined reference level is compensated by the decrease in the load resistance value. It is like that. Note that the relationship between the detected value and the set overlap amount is acquired in advance by experiments.

Thus, through steps S3 and S4, the variation in luminance characteristics between elements is reduced, and each of the light emitting elements 11a, 11b,... Can emit light with a luminance equivalent to the reference level uniformly. .

As the conductive functional liquid L, specifically, a liquid obtained by dispersing fine particles of a conductive material such as Au, Ag, or Pt in a dispersion medium is used. Such fine particles can also be used by coating the surface thereof with an organic substance (such as citric acid) in order to improve dispersibility. The dispersion medium is not particularly limited as long as it can disperse the above-described atomization and does not cause aggregation. Specifically, in addition to water, alcohols such as methanol and ethanol, hydrocarbon compounds such as n-heptane and toluene, ether compounds such as ethylene glycol dimethyl ether, propylene carbonate, N-methyl-2- Mention may be made of polar compounds such as pyrrolidone. These can be used alone or as a mixture of two or more.

In addition, the conductive functional liquid L is in consideration of the discharge characteristics and clogging properties of the droplet discharge device 200 (see FIG. 4), the stability of dispersion, the dynamic characteristics on the substrate after discharge, the drying speed, and the like. Appropriate adjustments have been made to the vapor pressure, dispersoid concentration, surface tension, viscosity, specific gravity and the like of the dispersion medium.
For this reason, a surfactant, a humectant, a viscosity modifier and the like can be added to the conductive functional liquid L.

Finally, a post-process such as packaging is performed (step S5 in FIG. 5), and the exposure head 10 (FIG. 1).
Reference) is completed.
(Modification)
Next, with reference to FIG. 7, the modification of this invention is demonstrated centering on difference with previous embodiment. FIG. 7 is a partial plan view showing a planar structure of the resistance element and the bypass wiring in the modification.

In the modified example, the bypass wirings 30a, 30b,... Extend integrally from the electrodes 24a, 24b, and extend between the resistance elements 22a, 22b, and the contact points between the resistance elements 22a, 22b, and so on. Are formed of contact portions 32a, 32b,. The elongated portions 31a, 31b,... Are formed with the same shape and dimensions, and the contact portions 32a, 32b,.

In this variation, the substantial load resistance value acting on the light emitting elements 11a, 11b (see FIG. 2) is determined by the positions of the contact portions 32a, 32b,. ing. That is, the positions of the contact portions 32a, 32b.
Since the load resistance value becomes smaller as it becomes closer to b..., the position of the contact portions 32a, 32b... is set so as to compensate for the variation in luminance characteristics between elements.

As in this modification, the bypass wiring can be formed so as to be parallel to the resistance element in the substrate surface direction, or can be formed by dividing the process.

The present invention is not limited to the above-described embodiment.
For example, an inorganic light-emitting diode or the like can be employed for the above-described light-emitting element.
Moreover, each structure of each embodiment can combine these suitably, can be abbreviate | omitted, or can combine with the other structure which is not shown in figure.

FIG. 3 is a cross-sectional view illustrating an internal configuration of an example of an image forming apparatus. FIG. 3 is a circuit diagram showing an electrical configuration of an exposure head. The partial top view which shows the planar structure of a resistive element and bypass wiring. FIG. 3 is a schematic diagram illustrating an example of a configuration of a droplet discharge device. The flowchart which shows the manufacturing process of an exposure head. (A) And (b) is a partial top view of the circuit in one process of manufacture. The partial top view which shows the planar structure of the resistive element and bypass wiring in a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Exposure head, 11a-11e ... Light emitting element, 13a-13e ... Drive switch, 14
DESCRIPTION OF SYMBOLS ... Source line, 15 ... Control circuit, 16 ... Shift register, 17 ... Latch circuit, 18 ... Decoder circuit, 19 ... Signal line, 20 ... Signal line, 21 ... Signal line, 22a-21e ... Resistance element, 23
a-23e: bypass wiring, 24: grounding wire, 24a, 24b ... electrode, 25a, 25b ... electrode, 30a, 30b ... bypass wiring, 31a, 31b ... elongating part, 32a, 32b ... contact part, 41 ... photoconductor drum 100: Image forming apparatus.

Claims (5)

An exposure module manufacturing method comprising a circuit in which a plurality of light emitting elements are connected in parallel,
A circuit forming step of forming the circuit including a resistance element connected in series to each of the plurality of light emitting elements;
A characteristic detection step of detecting a light emission characteristic for each of the plurality of light emitting elements;
A load adjustment step of adjusting a load resistance value acting on the light emitting element based on a detection result in the characteristic detection step,
The method of manufacturing an exposure module, wherein the load adjusting step is performed by partially connecting a bypass wiring to the resistance element in parallel. The method of manufacturing an exposure module according to claim 1, wherein the load adjustment step is performed using a droplet discharge method. An exposure module comprising a circuit in which a plurality of light emitting elements are connected in parallel,
An exposure module comprising: a resistance element connected in series to each of the plurality of light emitting elements; and a bypass wiring partially connected in parallel to the resistance element. 4. The exposure module according to claim 3, wherein the connection relationship between the bypass wiring and the resistance element is individually set for each of the corresponding light emitting elements. An image forming apparatus comprising the exposure module according to claim 3.

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