JP3501121B2 - Optical head and image forming apparatus using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical head and an image forming apparatus using the same, and more particularly, to an electroluminescent element formed of an organic thin film material on a substrate or a light emitting diode formed of an inorganic material. The present invention relates to an optical head in which a light emitting element is formed by using a light emitting element and a detection element is integrally formed at the same time when the light emitting element is formed, and an exposure function and a line image sensor are integrated, and an image forming apparatus using the same.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus using this type of electrophotographic process, especially when an attempt is made to form a high quality image by superimposing a plurality of colors on each other, the print position deviation between the colors is Means for detecting and means for correcting were needed.

In order to detect the positional deviation, it is necessary to provide a dedicated detecting means, but it is disclosed in Japanese Patent Laid-Open No. 11-157134.
In the printing apparatus disclosed in the above, a predetermined sensor for optically forming a pattern is formed on the transfer material conveying belt unit, and a dedicated sensor for optically detecting the pattern is provided to detect the positional deviation, and based on the positional deviation detection information. A technique for performing positional deviation correction is disclosed.

However, since the dedicated sensor for optically detecting the pattern is required to have high resolution and high accuracy, it is composed of a plurality of optical system parts, and the structure is complicated. In addition, high precision assembly is required, and the cost of the optical system and the number of assembling steps increase, resulting in an increase in manufacturing cost, resulting in an increase in cost of the apparatus.

[0005]

As described above,
In an image forming apparatus that forms images by superimposing a plurality of colors, when a high-quality image is obtained, if an optical exclusive sensor for detecting the print position deviation between each color is provided, this sensor has a high resolution. High accuracy is required, the optical system that composes the sensor becomes complicated, the manufacturing cost rises due to the increase in the cost of optical system parts and the number of assembly steps, and as a result, the cost of the image forming apparatus increases. There is a problem of inviting.

An object of the present invention is to form a latent image in which an exposure function and a line image sensor are integrated, in which a detection function is easily incorporated in a manufacturing process without separately providing such an expensive dedicated sensor as a detection means. An object is to provide a forming optical head and an image forming apparatus using the same.

[0007]

SUMMARY OF THE INVENTION An optical head according to the present invention includes a light emitting element which is two-dimensionally arranged in a row direction and a column direction, and an output light which is arranged in one row corresponding to each column of the light emitting element. the light
A detection element for detection, a row selection drive circuit that outputs a signal through a row output line to drive the light emitting element and the detection element, and a signal that outputs a signal through a column output line to drive the light emitting element and the detection element Drive circuit for writing light emission data, a light detection circuit connected to the light emitting element and the detection element through a column input line corresponding to the column output line to detect the light output of the light emitting element and the detection element, and for row selection And a control circuit for supplying a signal to the drive circuit and the light emission data writing drive circuit and inputting an output from the photodetector circuit to control the light emission data writing drive circuit.

The light emitting element and the detecting element are formed on the same transparent substrate.

The light emitting element comprises a thin film photodetection portion integrally formed on a transparent substrate, a light emitting portion formed of an organic thin film material and composed of an electroluminescence (EL) element, and a thin film transistor (TFT). And the photodetector has a sensitive region made of a thin film semiconductor and contact regions made of a thin film semiconductor arranged at both ends of the sensitive region to which a voltage is applied from the outside. It is characterized in that it has a layer, an opaque electrode and a transparent electrode formed with the organic EL layer sandwiched therebetween, and has a light shielding layer between the photodetection section and the transparent substrate.

The detection element includes a thin film photodetection section integrally formed on a transparent substrate, a light emitting section formed of an organic thin film material and composed of an electroluminescence (EL) element, and a thin film transistor (TFT). And the photodetector has a sensitive region made of a thin film semiconductor and contact regions made of a thin film semiconductor arranged at both ends of the sensitive region to which a voltage is applied from the outside. It is characterized in that it has a layer, an opaque electrode and a transparent electrode which are formed with the organic EL layer sandwiched therebetween, and has a light shielding layer between the photodetection section and the light emitting section.

The light emitting element includes a thin film photodetection portion formed on a transparent substrate, a transparent electrode, a light emitting portion formed of an inorganic material on the transparent electrode, and a thin film transistor (TFT).
The photodetector has a sensitive region made of a thin film semiconductor and contact regions made of a thin film semiconductor arranged at both ends of the sensitive region to which a voltage is applied from the outside. A light-shielding layer is provided between the substrate and the substrate.

The detection element comprises a thin film photodetection section formed on a transparent substrate, a transparent electrode, a light emitting section made of an inorganic material on the transparent electrode, and a thin film transistor (TFT).
The photodetector has a sensitive region made of a thin film semiconductor, and contact regions made of a thin film semiconductor arranged at both ends of the sensitive region to which a voltage is applied from the outside. It is characterized in that it has a light-shielding layer between it and the section.

In the light emitting portion, an n-type GaP substrate is formed on a transparent electrode, an n-type AlInP layer and a p-type A are formed on the n-type GaP substrate.
The light emitting diode is characterized by comprising a 1GaInP layer, a p-type AlInP layer, and a p-type GaP layer sequentially stacked.

The control circuit is characterized in that the light emitting elements arranged in a matrix are selected, and the light emitting sections in the light emitting elements are caused to emit light to perform control for forming an arbitrary light emitting pattern.

The control circuit is characterized by controlling the output of the light emitting portion by detecting a part of the light from the light emitting portion in the light emitting element by the light detecting portion.

The light emitting element detects a part of the light from the light emitting portion by the light detecting portion, the output light from the light emitting portion passes through the transparent substrate, and the reflected light from the outside is shielded by the light shielding layer and the light detecting portion. It is characterized in that it is not incident on.

The detecting element is characterized in that the output light from the light emitting portion passes through the transparent substrate and the reflected light from the outside is detected by the light detecting portion.

An image forming apparatus having the above optical head is characterized.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the optical head of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic block diagram showing a first embodiment of an optical head of the present invention, FIG. 2 (a) is a plan view showing a light emitting device 100 in FIG. 1, and FIG. 2 (b). Is shown in FIG.
3A is a cross-sectional view taken along the line AA, FIG. 3A is a plan view showing the detection element 101 in FIG. 1, and FIG. 3B is a BB shown in FIG.
A cross-sectional view, FIG. 4, shows a light emitting element 100 and a detection element 101.
3 is a schematic diagram of a circuit configuration of FIG.

The same constituent elements are indicated by the same reference numerals.

Referring to FIG. 1, the optical head 40 of the present invention.
Is a light emitting element 1 arranged two-dimensionally in the row direction and the column direction.
00, a row of detection elements 101 arranged corresponding to the light emitting elements 100 in each column direction, and a row selection drive that outputs a signal via the row output line 111 to drive the light emitting elements 100 and the detection elements 101. A circuit 110, a light emission data writing drive circuit 120 for outputting a signal via the column output line 121 to drive the light emitting element 100 and the detection element 101, and light emission via a column input line 131 corresponding to the column output line 121. Element 10
0 and the detection element 101, and a light detection circuit 130 for detecting the light output of the light emitting element 100 and the detection element 101,
A signal is supplied to the row selection drive circuit 110 and the light emission data write drive circuit 120, and the output from the photodetector circuit 130 is input to the light emission data write drive circuit 120.
And a control circuit 140 for controlling the above.

Referring to FIGS. 2A and 2B, the light emitting device 100 includes a light detecting portion 2 having a thin film structure integrally formed on the transparent substrate 10 and an electroluminescence device formed of an organic thin film material. A light emitting unit 1 including a sense (EL) element,
The thin film transistor (TFT) 3 is provided, and the light detection unit 2 is provided with a sensitive region 14a formed of a thin film semiconductor layer 14 of polysilicon and on which both ends of the sensitive region 14a are applied and a voltage is applied from the outside. The light emitting portion 1 includes the organic EL layer 21, the opaque electrode 22 formed with the organic EL layer 21 sandwiched therebetween, and the transparent electrode 20. Consists of
A light shielding layer 11 is provided between the light detection unit 2 and the transparent substrate 10 so that reflected light from the outside is blocked and does not enter the light detection unit 2, and the transparent electrode 20 is a thin film transistor (TF).
T) 3 source / drain electrodes 18 are connected.

Referring to FIGS. 3 (a) and 3 (b), the detection element 101 includes a photodetection section 2 having a thin film structure integrally formed on the transparent substrate 10, and an electroluminescence device formed of an organic thin film material. A light emitting unit 1 including a sense (EL) element,
The thin film transistor (TFT) 3 is provided, and the light detection unit 2 is provided with a sensitive region 14a formed of a thin film semiconductor layer 14 of polysilicon and on which both ends of the sensitive region 14a are applied and a voltage is applied from the outside. The light emitting portion 1 includes the organic EL layer 21, the opaque electrode 22 formed with the organic EL layer 21 sandwiched therebetween, and the transparent electrode 20. Consists of
A light shielding layer 11b is provided between the light detection unit 2 and the light emission unit 1 to block light emitted from the light emission unit 1 from entering the light detection unit 2, and the transparent electrode 20 is a thin film transistor (TF).
T) 3 source / drain electrodes 18 are connected.

The light emitting element 100 and the detection element 101 described above are both separated from the barrier layer 12 formed after forming the light shielding layer 11 on the transparent substrate 10 and the thin film semiconductor layer 14 on the barrier layer 12. A source / drain region 13b and a channel region 13a of the thin film transistor (TFT) 3 of the thin film semiconductor layer 13 formed, a gate insulating film 15 and a gate electrode 16 formed on the thin film semiconductor layer 13, an interlayer insulating film 17, Planarization film 1 formed of transparent insulating material
9 and the sealing layer 23.

Referring to FIG. 4, the light emitting section 1 and the light detecting section 2
Can be regarded as a two-terminal element (diode), and are denoted by LD and PD, respectively. Further, thin film transistors (TFTs) 3 connected to one ends of these LD and PD are denoted by symbols Tr1 and Tr3, respectively. Furthermore, an electrostatic capacitance Ch for holding the gate of Tr1 at a certain constant potential, and this electrostatic capacitance Ch
Tr2, which is a thin film transistor (TFT) 3 for charging the battery to a desired level, is connected to Tr1, and the source / drain electrodes 18 of Tr1 and Tr3 are generally power supply lines Vdd1 and Vdd to which different voltages are applied.
Connected to 2.

A capacitance Cs is connected in parallel to the PD. The gates of Tr2 and Tr3 are connected to the row output line 111 of the row selection drive circuit 110, and Tr
The second source / drain electrode 18 and the cathode of the PD are connected to the column output line 121 of the drive circuit 120 for writing the emission data and the column input line 131 of the photodetector circuit 130, respectively.

The difference between the light emitting element 100 and the detecting element 101 is that the light emitting element 100 emits light only and the internal PD
Is used for controlling the emission intensity, whereas the detection element 101 is operating as a sensor that receives the reflected light of the output light at the PD.

Referring to FIGS. 1 and 4, in all the light emitting elements 100 and the detection elements 101 in one row in the horizontal direction, the gate electrodes 16 of the transistors Tr2 and Tr3 correspond to the rows corresponding to the row selecting drive circuit 110. The source / drain electrodes 18 of the transistor Tr2 are connected to the corresponding column output line 121 of the emission data writing drive circuit 120 in all the light emitting elements 100 and the detection elements 101 connected to the output line 111 in one vertical direction. Further, the cathode of the PD (photodetection unit 2) is connected to the corresponding column input line 131 of the photodetection circuit 130, respectively.

Next, the optical head 4 constructed as described above.
The operation of 0 will be described with reference to the drawings.

Referring to FIGS. 1 and 4, first, desired voltage data is set to the electrostatic capacitances Ch of all the light emitting elements 100.

This is because the row selection drive circuit 110 outputs a signal to the row output line 111, and each light emitting element 100 is provided for each row.
It is realized by setting Tr2 in a conductive state, setting a desired voltage value in the light emission data writing drive circuit 120, and charging / discharging the corresponding Ch.

At the same time, a constant initial voltage is written from the power supply line Vdd2 to the electrostatic capacitance Cs of each light emitting element through Tr3.

When a desired voltage is written in the electrostatic capacitance Ch of each light emitting element 100, Tr1 is turned on and a desired current is supplied to the LD (light emitting section 1) of each light emitting element 100, as shown in FIG. As indicated by the arrow, light is emitted from the organic EL layer 21 toward the transparent substrate 10, and a part of the emitted light passes through the transparent substrate 10 and is emitted.

Thus, the light emitting elements 100 in rows and columns
By selectively emitting light, it is possible to obtain an arbitrary light emitting pattern, and it functions as the optical head 40 of the image forming apparatus 50.

Part of the light emitted from the organic EL layer 21 is also incident on the sensitive area 14a of the PD (photodetection section 2), and in this sensitive area 14a, the incident light causes electrons to be emitted. A hole pair is generated, which changes the electric conductivity of this region, and the electric charge stored in the electrostatic capacitance Cs is discharged through the PD (photodetection unit 2) according to the change.

Therefore, when the Cs of the light emitting element 100 is charged next, the current flowing from the outside is detected by the detection circuit 13.
The amount of light emitted from the LD (light emitting unit 1) can be known by detecting 0, and the capacitance C of each light emitting device 100 can be determined according to the output of the PD (light detection unit 2) of each light emitting device 100.
By correcting the voltage written in h, each light emitting element 1
The output of the LD (light emitting section 1) of 00 can be controlled.

The detection element 101 can also obtain an arbitrary light emission pattern similarly to the light emitting element 100, and when the LDs (light emitting portions 1) of all the detection elements 101 are made to emit light, the detection elements 101 output to the outside. The PD (light detection unit 2) detects the light that is reflected and returned from the above-described light, and thus functions as a line image sensor.

An image forming optical system (not shown) may be combined with the light emitting element 100 and the detecting element 101 to operate as an optical head 40 having a line image sensor function.

Next, a second embodiment of the optical head of the present invention will be described with reference to the drawings.

FIGS. 5 and 6 are sectional views showing a second embodiment of the light emitting element and the detecting element of the optical head of the present invention, respectively.

The same constituent elements of the light emitting element 100 and the detection element 101 shown in FIGS. 2 and 3 are denoted by the same reference numerals.

In the first embodiment, the light emitting element 100 of the optical head 40 and the light emitting section 1 of the detecting element 101 are formed by an organic thin film material, electroluminescence (EL).
The second embodiment is different from the light emitting element of the second embodiment only in that the light emitting section 4 is a light emitting diode formed of an inorganic material, and the light emitting element 103 and the detection element 104 are focused on. explain.

Referring to FIG. 5, the light emitting device 103 includes a light detecting portion 2 having a thin film structure integrally formed on the transparent substrate 10, a thin film transistor (TFT) 3, and a light emitting diode formed of an inorganic material. And the light detecting section 2 includes a thin film semiconductor layer 14 made of polysilicon.
And a contact region 14b disposed at both ends of the sensitive region 14a and containing a high concentration of phosphorus (P) element to which a voltage is applied from the outside. In No. 4, an n-type GaP substrate 81 is formed on the transparent electrode (cathode) 20, an n-type AlInP layer 82, a p-type AlGaInP layer 83, and a p-type A are formed on the n-type GaP substrate 81.
It is composed of a light emitting diode in which an lInP layer 84 and a p-type GaP layer 85 are sequentially stacked, and a bonding wire (anode) 86 connected to the upper surface of the light emitting diode. The light shielding layer 11 is provided so that the reflected light is shielded and does not enter the light detecting portion 2, and the transparent electrode 20 is connected to the source / drain electrode 18 of the thin film transistor (TFT) 3.

Referring to FIG. 6, the detection element 104 includes a thin film photodetection portion 2 integrally formed on the transparent substrate 10, a thin film transistor (TFT) 3, and a light emitting diode formed of an inorganic material. And the light detecting section 2 includes a thin film semiconductor layer 14 made of polysilicon.
And a contact region 14b disposed at both ends of the sensitive region 14a and containing a high concentration of phosphorus (P) element to which a voltage is applied from the outside. In No. 4, an n-type GaP substrate 81 is formed on the transparent electrode (cathode) 20, an n-type AlInP layer 82, a p-type AlGaInP layer 83, and a p-type A are formed on the n-type GaP substrate 81.
It is composed of a light emitting diode in which an lInP layer 84 and a p-type GaP layer 85 are sequentially stacked, and a bonding wire (anode) 86 connected to the upper surface of the light emitting diode, and a light emitting portion is provided between the light detecting portion 2 and the light emitting portion 4. The light emitted from 4 is the light detection unit 2
A light-shielding layer 11b that blocks direct incidence on the transparent electrode 20 is provided, and the transparent electrode 20 is connected to the source / drain electrode 18 of the thin film transistor (TFT) 3.

Regarding the operation of the optical head of the second embodiment using the light emitting element 103 and the detecting element 104 described above,
Since the operation is the same as that of the optical head 40 of the first embodiment, the description thereof will be omitted.

Next, a third embodiment of the optical head of the present invention will be described with reference to the drawings.

FIG. 7 is a schematic block diagram showing a third embodiment of the optical head of the present invention, and FIG. 8 is a light emitting element 10.
6 is a schematic diagram of a circuit configuration of 6 and a detection element 107. FIG.

The same components as those of the optical head 40 of the first embodiment shown in FIGS. 1 and 4 are designated by the same reference numerals.

Referring to FIGS. 7 and 8, in the optical head 41 of the third embodiment, the light emitting elements 106 in the pixels which are two-dimensionally arranged in the row direction and the column direction and the pixel columns are arranged. One row of detection elements 10 arranged corresponding to the light emitting elements 106
The configuration in which 7 is arranged is the same as that of the first embodiment, but the light emitting element 10 of the optical head 40 of the first embodiment is arranged.
The difference is that the photodetector 2 is deleted from 0 and the light emitter 1 is deleted from the detector 101 to form a light emitting element 106 and a detector 107, respectively.

This is the light emitting element 106 and the detecting element 107.
This is an effective means when the photodetector 2 and the light emitting unit 1 cannot be arranged close to each other due to restrictions in the manufacturing process of the above.

The detailed description of the optical head 41 of the third embodiment is omitted here.

Next, a first embodiment of an image forming apparatus using the optical head 40 of the present invention will be described with reference to the drawings.

FIG. 9 is a schematic configuration diagram showing a first embodiment of the image forming apparatus 50 of the present invention.

Referring to FIG. 9, the image forming apparatus 50 of the present invention includes a photoconductor belt 60 on which an image is written, a charger 62 for uniformly charging the surface of the photoconductor belt 60, and a photoconductor belt 60. First optical head 40-1, second optical head 40-2, third optical head 40-3, fourth optical head 40-4, and each color written, by exposing the surface to write an electrostatic latent image of each color To develop a toner image on the surface of the photoreceptor belt 60 by developing the electrostatic latent image of the first developing device 74-1, the second developing device 74-2, the third developing device 74-3, and the fourth developing device 74. -4
A transfer fixing unit 63 that transfers and fixes the developed image onto the sheet of paper 65, a static eliminator 61 that removes electric charges remaining on the surface of the photoconductor belt 60, a sheet feeding unit 66 that stores the sheet of paper 65, and a sheet feeding unit. It is composed of a pick roller 67 for picking the paper 65 from the paper unit 66 and a carrying roller 68 for carrying the picked paper 65.

The operation of the image forming apparatus 50 thus configured will be described below with reference to FIG.

Image forming apparatus 5 from a higher-level device (not shown)
When a print request is sent to the device control unit (not shown) in the device 0, the device control unit controls the first optical head 40-1, the second optical head 40-2, and the third optical head of each color. 40-3 and the fourth optical head 40-4 are activated to rotate the photoconductor belt 60, and the charger 62 and the static eliminator 61 are turned on.

When the activation of the optical head 40 is completed and the printable state is reached, the host device sends the image data of each color,
Writing of an electrostatic latent image on the photosensitive belt 60 is started by the optical head 40.

First optical head 40-1, second optical head 40
-2, the third optical head 40-3, and the electrostatic latent image written by the fourth optical head 40-4 are the first developing device 74-1, the second developing device 74-2, and the third developing device, respectively. The transfer fixing unit 63 transfers and fixes the paper 65 which has been developed by the 74-3 and the fourth developing device 74-4, and is further transported by the transport roller 68 from the paper feeding unit 66.

Next, the operation of the image forming apparatus 50 when the print position deviation is detected will be described with reference to FIGS. 9 and 1.

A predetermined pattern is exposed on the photoconductor 60 by the first optical head 40-1 to form an electrostatic latent image, and then development is performed by the first developing unit 74-1.

The predetermined pattern is sequentially detected by the detecting elements 101 inside the second optical head 40-2, the third optical head 40-3 and the fourth optical head 40-4.

At this time, the development by the second developing device 74-2, the third developing device 74-3 and the fourth developing device 74-4 is not performed.

Second optical head 40-2, third optical head 40
-3, the second optical head with respect to the position of the light emitting element 100 of the first optical head 40-1 based on the position and the detection timing of the pattern detected by the photodetection unit 2 of each detection element 101 of the fourth optical head 40-4. 40-2, the third optical head 40-3, the relative position of the light emitting element 100 of the fourth optical head 40-4 is calculated by an arithmetic circuit (not shown) in the control circuit 140, deviation from the design value. And the amount of this deviation is calculated by the control circuit 1
Correction control is performed by 40, and normal printing is performed.

For example, the shift amount of the light emission data to be written in the light emission data writing drive circuit 120 is canceled out.
Although the light emitting element 100 can be set from the control circuit 140 to obtain a high-quality image with no print position deviation, specific examples of the above deviation amount and correction control will be described below.

The positional relationship between the light emitting element 100 and the detection element 101 that form the optical head 40 of FIG. 1 in the image forming apparatus 50 of FIG. 9 is such that the running direction of the photoreceptor belt 60 is the row direction.
(A vertical direction on the paper surface of FIG. 1) , the direction orthogonal to the traveling direction is a column direction, the light emitting elements 100 are arranged in n rows and m columns, and the detection element 101 is adjacent to the nth row of the light emitting element 100. Arranged in 1 row and m columns (however, n,
m is a positive integer).

Of these elements, any light emitting element 10
0 is described as an i-th row and j-th column light emitting element 100, and a detection element 101 located in the same column as the i-th row and j-th column light emitting element 100 is described as a j-th column detection element 101.

First, in the procedure for measuring the print position deviation, the light emitting element 100 is turned on by the first optical head 40-1 in accordance with a predetermined pattern for measuring the print position deviation with reference to a predetermined time. After the latent image is formed on the photoconductor belt 60 and developed by the first developing device 74-1, the second optical head 40
It is detected by the detection element 101 of the second to fourth optical heads 40-4.

At this time, for example, when the second optical head 40-2 detects a specific pixel of a predetermined pattern as an expected value when the j2th row detection element 101 has a detection time t2 after the reference time, It is assumed that the actual detection is the j2 + j2′-th column detection element 101 and the detection time is after t2 + t2 ′.

Similarly, in the third optical head 40-3, the expected value is t3 after t3 from the reference time at the j3th row detection element 101, but actual detection is after t3 + t3 at the j3 + j3 ′ row detection element 101. , In the fourth optical head 40-4,
It is assumed that the expected value is actually t4 + t4 ′ after the j4 + j4′-th column detection element 101, after t4 at the j4th-column detection element 101.

Then, the displacement amount of the second optical head 40-2 is j2 ′ pixels in pixels in the direction orthogonal to the traveling direction of the photosensitive belt 60, and the displacement amount is in the traveling direction of the photosensitive belt 60. Is t2 'in time.

Similarly, the third optical head 40-3 has j3 '
Pixels and t3 ′ time, the fourth optical head 40-4 has j
It will be respectively shifted by 4'pixels and t4 'time.

Therefore, at the time of normal printing, the second optical head 40-2 to the fourth optical head 4 are used to correct this deviation amount.
In 0-4, the exposure start times are t2 ′, t3 ′, t
4'later, j2 ', j3', j4 'in the column direction
Exposure is performed with the light emitting device 100 that is shifted only.

Next, a second embodiment of an image forming apparatus using the optical head 41 of the third embodiment of the optical head of the present invention will be described with reference to the drawings.

FIG. 10 is a schematic block diagram showing the image forming apparatus 51 of the second embodiment.

The same components as those of the image forming apparatus 50 of the first embodiment shown in FIG. 9 are designated by the same reference numerals.

The image forming apparatus 51 of the second embodiment is
A configuration of a light emitting element 106 and a detection element 107 which are formed by removing the light detecting section 2 from the light emitting element 100 of the optical head 40 of the first embodiment and deleting the light emitting section 1 from the detecting element 101, respectively. Using the optical head 41 of the above-described third embodiment, the second optical head 41-2, the third optical head 41-3, and the fourth optical head 41 except the first optical head 41-1 are used.
4 is different from the image forming apparatus 51 of the first embodiment only in that the second light source 55-2, the third light source 55-3, and the fourth light source 55-4 are provided in each.

In the image forming apparatus 51, since the detecting element 107 of the optical head 41 does not have the light emitting section 1, the second light source 55-2 and the third light source 55-3 are used instead of the light emitting section 1 only when the print position deviation is detected. , The fourth light source 55-4 is turned on, and the control circuit 1
The printing position deviation is corrected by the control unit 40, and the other operations are the same as those of the image forming apparatus 50, and detailed description thereof will be omitted.

[0079]

As described above, by using the optical head having the line image sensor function and the exposure function integrated with each other, it is possible to detect and correct the print position deviation, and print at a low cost and with high accuracy. There is an effect that it is possible to provide an image forming apparatus that produces a high-quality image without misalignment.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing a first embodiment of an optical head of the present invention.

2 (a) is a plan view showing the light emitting element in FIG. 1, and FIG. 2 (b) is a sectional view taken along the line AA in FIG. 2 (a).

3 (a) is a plan view showing the detection element in FIG. 1, and FIG. 3 (b) is a BB sectional view of FIG. 3 (a).

FIG. 4 is a schematic diagram of a circuit configuration of a light emitting element and a detection element in the first embodiment of the optical head of the present invention.

FIG. 5 is a sectional view of a light emitting element showing a second embodiment of the optical head of the present invention.

FIG. 6 is a sectional view of a detection element showing a second embodiment of the optical head of the present invention.

FIG. 7 is a schematic block diagram showing a third embodiment of an optical head of the present invention.

FIG. 8 is a schematic diagram of a circuit configuration of a light emitting element and a detection element according to a third embodiment of the optical head of the present invention.

FIG. 9 is a schematic configuration diagram showing a first embodiment of an image forming apparatus of the present invention.

FIG. 10 is a schematic configuration diagram showing a second embodiment of the image forming apparatus of the invention.

[Explanation of symbols]

1, 4 light emitting part 2 Photodetector 3 Thin film transistor (TFT) 10 Transparent substrate 11, 11b Light shielding layer 12 Barrier layer 13, 14 Thin film semiconductor layer 13a channel area 13b source / drain region 14a Sensitive area 14b Contact area 15 Gate insulation film 16 gate electrode 17 Interlayer insulation film 18 Source / drain electrodes 19 Flattening film 20 Transparent electrode 21 Organic EL layer 22 Opaque electrode 23 Sealing layer 40, 41 Optical head 40-1, 41-1 first optical head 40-2, 41-2 Second optical head 40-3, 41-3 Third optical head 40-4, 41-4 Fourth optical head 50, 51 image forming apparatus 55-2 Second light source 55-3 Third light source 55-4 Fourth light source 60 photoconductor belt 61 Static eliminator 62 charger 63 Transfer fixing unit 65 sheets 66 paper feed unit 67 Pick roller 68 Conveyor roller 74-1 First developing device 74-2 Second developing device 74-3 Third developer 74-4 Fourth developing device 81 n-type GaP substrate 82 n-type AlInP layer 83 p-type AlGaInP layer 84 p-type AlInP layer 85 p-type GaP layer 86 Bonding wire (anode) 100, 103 Light emitting element 101, 104 detection element 106 light emitting element 107 detection element 110 row selection drive circuit 111 line output line 120 Drive circuit for writing light emission data 121 column output line 130 Photodetector circuit 131 column input line 140 control circuit

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Claims (12)

(57) [Claims] 1. A light-emitting element arranged two-dimensionally in a row direction and a column direction, and arranged in one row corresponding to each column of the light-emitting element.
A detection element that detects reflected light of the output light, a row selection drive circuit that outputs a signal through a row output line to drive the light emitting element and the detection element, and a signal through a column output line A drive circuit for writing light emission data that drives the light emitting element and the detection element, and the light emitting element and the detection element that are connected to the light emitting element and the detection element via a column input line corresponding to the column output line. A light detection circuit for detecting a light output from an element, a signal for supplying to the row selection drive circuit and the light emission data write drive circuit, and an input from the light detection circuit for inputting the light emission data write drive An optical head having a control circuit for controlling the circuit. 2. The optical head according to claim 1, wherein the light emitting element and the detection element are formed on the same transparent substrate. 3. The light emitting element, a light detecting portion having a thin film structure integrally formed on the transparent substrate, a light emitting portion formed of an organic thin film material and including an electroluminescence (EL) element, and a thin film transistor. (TFT),
The light detection unit has a sensitive region made of a thin film semiconductor and contact regions made of a thin film semiconductor arranged at both ends of the sensitive region to which a voltage is applied from the outside, and the light emitting unit is an organic EL layer. 2. An optical head according to claim 1, further comprising: an opaque electrode and a transparent electrode formed with the organic EL layer sandwiched therebetween, and a light-shielding layer between the photodetection section and the transparent substrate. . 4. The detection element, a light detection section having a thin film structure integrally formed on the transparent substrate, a light emitting section formed of an organic thin film material and including an electroluminescence (EL) element, and a thin film transistor. (TFT),
The light detection unit has a sensitive region made of a thin film semiconductor and contact regions made of a thin film semiconductor arranged at both ends of the sensitive region to which a voltage is applied from the outside, and the light emitting unit is an organic EL layer. And an opaque electrode and a transparent electrode formed with the organic EL layer sandwiched therebetween, and a light-shielding layer between the photodetection section and the light emitting section.
The described optical head. 5. The light emitting element comprises a thin film photodetection portion formed on the transparent substrate, a transparent electrode, a light emitting portion formed of an inorganic material on the transparent electrode, and a thin film transistor (TFT). And the photodetector has a sensitive region made of a thin film semiconductor and contact regions made of a thin film semiconductor arranged at both ends of the sensitive region to which a voltage is applied from the outside. The optical head according to claim 1, further comprising a light-shielding layer between the portion and the transparent substrate. 6. The detection element comprises a thin film photodetection section formed on the transparent substrate, a transparent electrode, a light emitting section formed of an inorganic material on the transparent electrode, and a thin film transistor (TFT). And the photodetector has a sensitive region made of a thin film semiconductor and contact regions made of a thin film semiconductor arranged at both ends of the sensitive region to which a voltage is applied from the outside. The optical head according to claim 1, further comprising a light shielding layer between the light emitting portion and the light emitting portion. 7. The light emitting unit comprises an n-type G on the transparent electrode.
An aP substrate is formed, and n-type AlI is formed on the n-type GaP substrate.
nP layer, p-type AlGaInP layer, p-type AlInP layer, p
7. The optical head according to claim 5, wherein the optical head comprises a light emitting diode in which type GaP layers are sequentially stacked. 8. The control circuit performs control to select the light emitting elements arranged in a matrix and cause the light emitting units in the light emitting elements to emit light to form an arbitrary light emitting pattern. The optical head according to item 1. 9. The control circuit controls the output of the light emitting unit by detecting a part of the light from the light emitting unit in the light emitting element by the light detecting unit. 1. The optical head described in 1. 10. The light emitting element detects a part of the light from the light emitting portion by the light detecting portion, the output light from the light emitting portion passes through the transparent substrate, and the reflected light from the outside is 6. The optical head according to claim 1, wherein the optical head is shielded by a light shielding layer and does not enter the light detecting portion. 11. The detection element is characterized in that the output light from the light emitting section passes through the transparent substrate and the reflected light from the outside is detected by the light detection section.
The optical head according to claim 1. 12. An image forming apparatus having the optical head according to claim 1. Description: