JP3302330B2 - Light emitting device, exposure device and image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-emitting device, an exposure device, and an image forming device. The present invention relates to an exposure apparatus that is arranged in a row to form a light emitting array.

[0002]

2. Description of the Related Art As is well known, an electrophotographic method is a process in which an image is exposed on a photoconductor, developed with toner, transferred to a transfer material (paper), fixed, and the photoconductor is cleaned. Therefore, use for an image forming apparatus is active.

In such an image forming apparatus, a laser optical system that scans a laser beam with a polygon mirror is widely used as an exposure unit for writing a latent image on the surface of a photosensitive member because of its high resolution and high speed. ing.
However, in the case of a laser optical system, a space for arranging optical components such as a polygon mirror and a lens is required, which makes it difficult to reduce the size of the device, and because the scanning is performed dynamically by rotating the polygon mirror. However, there is a problem that it is difficult to increase the speed.

[0004] Therefore, a light-emitting array having a plurality of organic light-emitting elements arranged in an array has been attracting attention. This is a linear light-emitting body, and static scanning is performed, thereby simplifying an optical system. Application to electrophotographic exposure units is increasing. For example, as a linear light-emitting array, a transparent anode layer, an organic compound layer, and a cathode layer are sequentially laminated on a long-strip light-transmitting substrate, and the front and back of the strip-shaped organic compound layer are formed in a predetermined pattern of electrodes. A proposal has been made in which an array of light-emitting elements that individually emit light is sandwiched between layers.

[0005]

However, in the case of a luminous array in which organic compounds are stacked, the organic compounds have the characteristic of being weak to water, and the deterioration is accelerated even under the condition that the humidity in the atmosphere is somewhat high. For this reason, there has been a problem that the organic light emitting element is deteriorated and its life is shortened.

Accordingly, the present invention has been made in view of the above-mentioned conventional problems, and a light emitting device, an exposure device, and an image display device capable of preventing the influence of moisture in the atmosphere on a light emitting element made of an organic compound and achieving a long life. It is an object of the present invention to provide an exposure apparatus which can be preferably applied to a forming apparatus, particularly an electrophotographic exposure section.

[0007]

In order to achieve the above object, a light emitting device according to the present invention has a light emitting body array in which a plurality of organic light emitting elements are arranged in a row, and the organic light emitting elements correspond to input data. In the light emitting device driven and driven, a temperature detecting means for detecting the temperature of the organic light emitting element, a heat generating means attached to the vicinity of the organic light emitting element and generating heat in response to a drive signal, and detecting the temperature from the temperature detecting means And a control means for driving the heating means on and off so that the detection value becomes a predetermined value capable of preventing the influence of moisture in the atmosphere upon receiving the output.

An exposure apparatus according to the present invention has an illuminant array in which a plurality of organic light emitting elements are arranged in a line, and drives the organic light emitting elements in accordance with input data. Temperature detecting means for detecting the temperature of the element, heat generating means attached to the vicinity of the organic light emitting element and generating heat in response to a drive signal, and a detection value received from the temperature detecting means and the detected value is the humidity in the atmosphere. Can prevent the effects of
Control means for turning on and off the heating means so as to attain a predetermined value.

Further, an image forming apparatus according to the present invention is characterized by having at least the above-mentioned exposure device and a photoreceptor exposed by the exposure device.

In the light emitting device, the exposure device and the image forming apparatus of the present invention, the temperature of the organic light emitting element is detected by the temperature detecting means, and the temperature is detected by the control means which receives the detection output from the temperature detecting means. Value is humidity in the atmosphere
The heating means is turned on and off so as to have a predetermined value which can prevent the influence of the heat generation. As a result, the organic light emitting element is preheated by the heat generated by the heat generating means in a standby state where there is no input data, and is maintained at a predetermined temperature.

Further, since the organic light-emitting element is kept at a predetermined temperature in a waiting state where there is no input data, the rise of light emission is improved during the original driving according to the input data, and the initial response of the light-emitting drive is improved. And the stability of the response operation is also improved.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 to 5 show a first embodiment of the present invention. FIG. 1 is a configuration diagram of a light emitting device and an exposure device according to the present invention, FIG. 2 is a perspective view of the light emitting array, and FIG. FIG. 4 is a cross-sectional view showing the layer structure of the light emitting element, FIG. 4 is a flowchart of preheating control of the light emitting element, and FIG. 5 is a graph showing the result of measuring the temperature of the light emitting array.

This device comprises a luminous element array 709 and a drive control unit 701 for the luminous element array 709.
09 includes a number of light emitting elements 707, a heating element 708, and a temperature sensor 706.
02, ROM 703, RAM 704, I / O port 70
Consists of five. And CPU702, ROM703, R
A CPU in which the AM 704 and the input / output port 705 are connected by a control line and captures input data such as image information.
Various data, addresses, and the like are transmitted to each unit via a control line by a control line 702, and an input / output port 705 is connected to a temperature sensor 706, a light emitting element 707, and a heating element 708 by an input / output line, and detection is performed. A drive signal corresponding to input data such as a signal and image information is transmitted and received.

As shown in FIG. 2, the light emitting element array (1) has a large number of light emitting elements 2 on a long strip-shaped translucent substrate 21.
Are arranged in a row (array), and a driver circuit pattern 3 for causing the light emitting elements 2 in the row to emit light in accordance with image information is provided adjacent to the row. Further, a long-strip heating element 5 is provided along the light-emitting elements 2 in the row, and a plurality of temperature sensors 4 are provided at predetermined intervals adjacent to the heating element 5.
These are connected to the input / output port (705) described above. The distance between the light emitting element 2, the heating element 5, and the temperature sensor 4 is set such that the heat conduction of the three elements substantially coincides with each other. This has a great influence on the heat conduction characteristics of the light-transmitting substrate 21, but in consideration of this point, in the present embodiment, the distance between the three members is set to be substantially the same.

The heating element 5 is an electric heater made of an electric resistor, and is formed by forming a thin film-shaped electric resistor into a long band shape, and is turned on and off by a driving signal sent from an input / output port (705).

The light-emitting elements 2 in a row are so-called organic light-emitting elements, which are collectively formed by lamination. As shown in FIG. 3, a transparent anode layer 20 is formed on a light-transmitting substrate 201.
2. An organic compound layer 203 and a cathode layer 204 are sequentially stacked, and a row of light-emitting elements that individually emit light is collectively formed by sandwiching the front and back of the band-shaped organic compound layer 203 between electrode layers 202 and 203 having a predetermined pattern. The configuration is as follows.

As the substrate 201, any substrate capable of holding a light emitting element on its surface may be used. For example, a transparent insulating substrate made of glass such as soda lime glass or a resin film is preferably used.

As a material of the anode layer 202, a material having a large work function is desirable, and for example, ITO, tin oxide, gold, platinum, palladium, selenium, iridium, copper iodide and the like can be used. On the other hand, the material of the cathode layer 204 is desirably a material having a small work function, for example, Mg / A
g, Mg, Al, In, or an alloy thereof can be used.

The organic compound layer 203 may have a single-layer structure or a multi-layer structure. For example, the organic compound layer 203 may include a hole transport layer into which holes are injected from the anode layer 202 and a cathode layer 204. It consists of an electron transport layer into which electrons are injected, and one of the hole transport layer and the electron transport layer becomes a light emitting layer. Also,
A phosphor layer containing a phosphor may be provided between the hole transport layer and the electron transport layer. Further, a configuration in which a hole transport layer, an electron transport layer, and a fluorescent layer are also used in a mixed single layer configuration is also possible.

As the hole transport layer, for example, N, N'-
Bis (3-methylphenyl) -N, N'-diphenyl-
(1,1′-biphenyl) -4,4′-diamine (TPD) can be used, and the following organic materials can also be used.

[0022]

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[0023]

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[0024]

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[0025]

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[0026]

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Further, for example, an inorganic material such as a-Si or a-SiC may be used.

As the electron transporting layer, for example, Tris (8
-Quinolinol) aluminum (hereinafter Alq ₃ ), and the following materials can also be used.

[0029]

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[0030]

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[0031]

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[0032]

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Further, a dopant as shown below can be doped into the electron transporting layer or the hole transporting layer.

[0034]

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Further, it is preferable to provide a dielectric layer between the anode layer 202 and the substrate 201. The dielectric layer is Si
By laminating layers having different refractive indexes such as O ₂ and SiO, it is possible to increase (lower) the reflectance and transmittance at a specific wavelength. Alternatively, it is also possible to simply use a half mirror.

It is preferable to provide a protective layer (sealing layer) on the upper surface of the cathode layer 204 by laminating an insulating and moisture-proof material in order to protect the surface layer, prevent deterioration and prevent short-circuiting of the electrodes. .

The CPU 702 controls each section in accordance with input data such as image information and the like.
The preheating control is performed on the light-emitting elements 707 by the heating element 708, and the temperatures of the light-emitting elements 707 are maintained at a preset target temperature when there is no input data such as image information or the like.

As shown in FIG. 4, the preheating control of the CPU 702 is performed when there is no input data in the standby state [Step 80].
1] First, the temperature is measured by the temperature sensor 706 [procedure 802]. Then, it is determined whether the target temperature Ts stored in the ROM 703 has been reached in advance [Step 8].
03]. If the temperature is lower than the target temperature Ts [NO in step 803], the heating element 708 is turned on [step 805], and the process returns to the step 802 for performing temperature measurement. On the other hand, when the target temperature Ts has been reached [YES in step 803], the heating element 7
08 is turned on or not [procedure 804]. Here, when the heating element 708 is in the ON state, [YE
S], the heating element 708 is immediately turned off [procedure 80].
6], and return to the procedure 802 for performing temperature measurement. Heating element 708
Is in the OFF state [NO in step 804], the process returns to step 802 for performing temperature measurement.

Accordingly, the heating element 708 generates heat when it is turned on. This is performed when there is no input data such as image information, so that the light emitting element 707 is preheated, as shown in FIG. As described above, in the waiting state where there is no input data, the preheating target temperature Ts indicated by the broken line is maintained.

It should be noted that the signal level for driving the heating element 708 ON may be set as appropriate, and the response of the preheating control can be changed by increasing or decreasing the signal level.

With the above configuration, the device of the present embodiment is operated by the temperature sensor 706 attached to the light emitting array 709.
The temperature of the light emitting elements 707 in the row is detected, and the CPU 702 that has received the detection output from the temperature sensor 706 drives the heating element 708 on and off so that the detection value becomes the target temperature Ts in a standby state where there is no input data. Is done. Thus, the light-emitting element 707 made of an organic compound
Is preheated by the heat generated by the heating element 708 in a standby state where there is no input data, and is kept at a preset target temperature Ts. Therefore, the influence of moisture in the atmosphere can be prevented, and dew condensation can be prevented. As a result, the light emitting element 70 made of an organic compound
7 can be suppressed, and the life can be extended.

Further, since the light emitting element 707 is kept at a predetermined temperature in a waiting state where there is no input data, the rising of light emission is improved at the time of the original driving according to the input data,
The initial response of the light emission drive can be improved, and the stability of the response operation can be improved. For this reason, it is preferable that the exposure section of the electrophotographic system can achieve high speed and high image quality.

In the present embodiment, the preheating control for the heating element 708 is performed when there is no input data such as image information or the like, but the procedures 801 to 8 shown in FIG.
06 may be operated when the power of the apparatus is turned on, so that preheating control is always performed. In that case, the light-emitting elements 707 in the array are self-heated during the original driving according to the input data because they are turned on and off according to the input data, and as shown in FIG. Exceeds the target temperature Ts. So at that time,
The preheating control for the heating element 708 is a control operation that keeps the heating element 708 off, and there is no problem since it is substantially canceled.

FIG. 6 shows a second embodiment of the present invention, which is an example of an image forming apparatus using an exposure apparatus according to the present invention. FIG. 6 is a diagram showing the configuration of an electrophotographic image forming apparatus. is there.

In this image forming apparatus, a charging means 212 and a rotating drum type photoreceptor 211 are provided around an image bearing member.
Developing means 213, transfer means 214, cleaning means 2
16 are arranged in order, an exposing unit 217 is arranged between the charging unit 212 and the developing unit 213, and a fixing unit 215 is arranged in a discharge path of the transfer material P such as recording paper.

Exposure means 217 is one to which the exposure apparatus of the present invention is applied, in which a selfoc lens array 32 is disposed in front of the light emitter array 1, and the light emission output of the light emitter array 1 is provided by the selfoc lens array 32. Is appropriately guided as the exposure L, and the exposure L can be imaged on the photoconductor 211, so that a good latent image can be obtained.

In the image formation, first, the photosensitive member 211 is uniformly charged by the charging means 212. Exposure L is performed on the charged surface of the photoconductor 211 by exposure means 217 in accordance with a time-series electric digital pixel signal as image information, and an electrostatic latent image corresponding to the image information is formed on the peripheral surface of the photoconductor 211. Is formed. The electrostatic latent image is developed as a toner image by developing means 213 using insulating toner. On the other hand, a transfer material P as a recording material is supplied from a paper feeding unit (not shown),
The photoconductor 211 is introduced at a predetermined timing into a pressure contact nip (transfer portion) T pressed against the photoconductor 211 with a predetermined pressure, and performs a transfer by applying a predetermined transfer bias voltage.

The transfer material P which has undergone the transfer of the toner image is separated from the surface of the photoconductor 211, and is introduced into a fixing means 215 such as a heat fixing system, where the toner image is fixed to form a print (image). It is discharged outside the device. Further, the surface of the photoconductor 211 after the transfer of the toner image to the transfer material P is cleaned by a cleaning unit 216 to remove adhered contaminants such as residual toner, and is repeatedly used for forming a latent image.

In this case, the exposure means 217 for performing the electrophotographic exposure process is composed of the exposure apparatus of the present invention. Therefore, the organic light emitting element of the exposure apparatus causes the heating element to generate heat when there is no input data. As a result, it is possible to prevent the influence of moisture in the atmosphere and prevent dew condensation. As a result, the deterioration of the organic light emitting element can be suppressed, and the life can be extended, which is preferable for an electrophotographic exposure unit. Also, since the organic light emitting element is preheated, during the original driving according to the input data,
Since the rise of the light emission is improved, the initial response of the light emission drive can be improved, and the stability of the response operation is also improved.
It is preferable that the exposure unit of the electrophotographic system achieves high speed and high image quality.

FIG. 7 shows a third embodiment of the present invention, which is another example of an image forming apparatus using the exposure apparatus according to the present invention. FIG.

In this image forming apparatus, in order to form a multi-color image, four process components up to electrophotographic transfer are arranged in a row, and the transfer material P passes through the four consecutive process components in order. Thus, the sheet is conveyed to the fixing unit F1.

That is, the photosensitive drums 301 to 301 of the rotating drum type
04 are arranged in order from the upstream side of the transfer belt TF1 passed between the two rollers TR1 and TR2.
1 to C4, exposure means E1 to which the exposure apparatus of the present invention is applied
E4, developing means D1 including developing sleeves S1 to S4
D4, transfer blades T1 to T4 are arranged, and a fixing means F1 is provided in a discharge path of the transfer material P.

The transfer material P is transported in the direction of the arrow,
The transfer belt TF1 guides the transfer belt TF1 onto the transfer belt TF1 suspended on R1 and TR2, and moves to a black transfer position set between the photosensitive member 301 and the transfer blade T1. At this time, the photoreceptor 301 has a predetermined black toner image by an electrophotographic process using a charging means C1, an exposing means E1, and a developing sleeve S1 of a developing means D1 arranged on the periphery of the drum. The transfer of the black toner image is performed.

Further, the transfer material P is conveyed by the transfer belt TF1, and is set to a cyan transfer position set to be sandwiched between the photosensitive member 302 and the transfer blade T2, and set to be set to be sandwiched between the photosensitive member 303 and the transfer blade T3. Sequentially moves to the magenta transfer position and the yellow transfer position set between the photosensitive member 304 and the transfer blade T4. At each transfer position, the cyan toner image and the magenta The transfer of the toner image and the yellow toner image is performed.

In this case, since each of the photoconductors 301 to 304 is rotating favorably, the image registration can be favorably performed between the transfer recordings. The transfer material P on which the multicolor recording has been performed by the above process is guided to the fixing unit F1 to be fixed, whereby a multicolor image can be obtained.

In such a multi-color image forming apparatus, since there are a plurality of electrophotographic processes, there is a problem with the organic light emitting element in the conventional exposure apparatus, that is, deterioration of the organic light emitting element due to moisture in the atmosphere. However, the problem that the life is shortened due to the progress of the process also affects a plurality or multiple layers. However, since the exposure units E1 to E4 by the exposure apparatus of the present invention are provided,
In each exposure means, the organic light-emitting element is preheated by the heat of the heating element in a waiting state where there is no input data, and is kept at the set temperature, so that the influence of moisture in the atmosphere can be prevented, and dew condensation can be prevented, As a result, the effect of the problem can be reduced even in the case of a plurality of components, and therefore, it is preferable for a multicolor electrophotographic exposure unit. In addition, since the organic light-emitting element is preheated, the rising of light emission is improved during the original driving according to the input data, the initial response of the light-emitting drive can be improved, and the stability of the response operation is also improved. For this reason, it is preferable that the exposure unit of the multi-color electrophotographic system achieves high speed and high image quality, and a high-quality multi-color image can be obtained.

[0057]

As described above, according to the present invention, the temperature of the organic light emitting element is detected by the temperature detecting means, and the detected value is determined by the control means which receives the detection output from the temperature detecting means . The heat generating means is turned on and off so as to have a predetermined value that can prevent the influence of moisture . Thereby, the organic light emitting element is preheated by the heat of the heat generating means in a waiting state where there is no input data, and is maintained at a predetermined temperature set in advance, so that the influence of moisture in the atmosphere can be prevented and dew condensation can be prevented. . As a result, deterioration of the light emitting element due to the organic compound can be suppressed, and the life can be extended.

Further, since the organic light emitting element is kept at a predetermined temperature in a waiting state where there is no input data, the rising of light emission is improved at the time of the original driving according to the input data, and the initial response of the light emission driving is improved. And the stability of the response operation is also improved. For this reason, it is preferable that the exposure section of the electrophotographic system can achieve high speed and high image quality.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a light emitting device and an exposure device according to a first embodiment of the present invention.

FIG. 2 is a perspective view of the light emitter array of FIG.

FIG. 3 is a cross-sectional view illustrating a layer configuration of the light emitting device of FIG.

FIG. 4 is a flowchart of preheating control of a light emitting element.

FIG. 5 is a graph showing the results of measuring the temperature of the light emitting array.

FIG. 6 is a configuration diagram of an example of an electrophotographic image forming apparatus according to a second embodiment of the present invention.

FIG. 7 is a configuration diagram of another example of an electrophotographic image forming apparatus according to a third embodiment of the present invention.

[Explanation of symbols]

 1,709 light emitting element array 2,707 organic light emitting element 4,706 temperature sensor (temperature detecting means) 5,708 heating element (heating means) 217 exposure means (light emitting device) 702 CPU (control means) E1, E2, E3 E4 Exposure means (light emitting device) Ts Target temperature (predetermined value)

Continuation of the front page (51) Int.Cl. ⁷ Identification code FI H04N 1/036 1/04 101 (72) Inventor Yukio Nagase 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) Reference Document JP-A-6-45654 (JP, A) JP-A-3-46676 (JP, A) JP-A-7-263742 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41J 2/44 B41J 2/45 B41J 2/455 G03G 15/04 111 G03G 21/20 H04N 1/036 H04N 1/04 101

Claims (15)

(57) [Claims] 1. A light emitting apparatus having a light emitting array in which a plurality of organic light emitting elements are arranged in a row and driving the organic light emitting elements in accordance with input data, a temperature for detecting a temperature of the organic light emitting elements. detection means, detection value receiving a heating means for heating in response to the drive signal is attached to the proximal tufts, the detection output from said temperature detecting means of the organic light emitting element is cut
A light emitting device comprising: a control unit that turns on and off the heat generating unit so that the heat generating unit has a predetermined value that can prevent the influence of moisture in the surroundings . 2. The light emitting device according to claim 1, wherein the control unit drives the heat generating unit when there is no input data to the organic light emitting element in a waiting state. 3. The organic light-emitting device according to claim 1, wherein the substrate comprises at least an anode layer and a cathode layer, and one or more organic compound layers sandwiched therebetween. 3. The light emitting device according to 2. 4. The light emitting device according to claim 1, further comprising a temperature detecting means and a heat generating means near the light emitting element. 5. The light emitting device according to claim 1, wherein the temperature detecting means and the heat generating means are provided on a substrate of the luminous body array. 6. The light emitting device according to claim 1, wherein the temperature detecting means and the heat generating means are formed by a process similar to a light emitting element forming process. 7. The light emitting device according to claim 1, wherein the distance between the light emitting element, the heat generating means, and the temperature detecting means is substantially the same. 8. An exposure apparatus having a light-emitting body array in which a plurality of organic light-emitting elements are arranged in a row and driving the organic light-emitting elements in accordance with input data, a temperature for detecting a temperature of the organic light-emitting elements. detection means, detection value receiving a heating means for heating in response to the drive signal is attached to the proximal tufts, the detection output from said temperature detecting means of the organic light emitting element is cut
An exposure apparatus comprising: a control unit that drives the heating unit to be turned on and off so as to have a predetermined value that can prevent the influence of moisture in the surroundings . 9. The exposure apparatus according to claim 8, wherein the control unit drives the heating unit when there is no input data to the organic light emitting element in a waiting state. 10. The organic light-emitting device according to claim 8, wherein the substrate comprises at least an anode layer and a cathode layer, and one or more organic compound layers sandwiched therebetween. 10. The exposure apparatus according to 9. 11. The exposure apparatus according to claim 8, further comprising a temperature detecting unit and a heat generating unit near the light emitting element. 12. The light emitting device according to claim 8, wherein the temperature detecting means and the heat generating means are provided on a substrate of the light emitting array.
3. The exposure apparatus according to claim 1. 13. The exposure apparatus according to claim 8, wherein the temperature detecting means and the heat generating means are formed by a process similar to a light emitting element forming process. 14. The exposure apparatus according to claim 8, wherein the light emitting element, the heat generating means, and the temperature detecting means have substantially the same distance from each other. 15. An exposure apparatus according to claim 8, wherein:
An image forming apparatus comprising at least a photoconductor exposed by the exposure apparatus.