JPH11179954A - Exposure apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exposure apparatus capable of shortening an exposure time and to enable the high speed image output of an image forming apparatus and reduced the number of signal lines for connecting driver parts and chips. SOLUTION: An image forming means constituted by arranging a plurality of light emitting element chips having first and second light emitting element rows wherein light emitting element rows formed by arranging a plurality of light emitting elements are mutually arranged almost in parallel and emitting beams to a photosensitive member from the first and second light emitting element rows 1001, 2000 to form an image is provided. The first and second light emitting element rows 1001, 2001 are constituted by arranging a large number of light emitting thyristors 1034, 1036, 1044, 1046, 2034, 2036, 2044,2046 capable of electrically controlling threshold voltage or current and drive parts are formed by connecting vicinal light emitting thyristors mutually by electric elements having the unidirectionality of voltage or current and selfscanning is performed by two-phase transmission clocks ϕ1, ϕ2. The first and second light emitting element rows 1001, 1002 use the twophase transmission clocks ϕ1, ϕ2, the power supply line necessary for light emitting operation and a start clock line for performing the start of transmission in common.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus used as an exposure system of an image forming apparatus such as a printer, a facsimile, and a copying machine for forming a monochrome image and a color image.

[0002]

2. Description of the Related Art Conventionally, most image forming apparatuses such as printers, facsimile machines, digital copiers and the like use an electrophotographic system, which includes image signals output from an external computer or an image reading system. An exposure system using a light source in which light emitting elements such as light emitting diodes are arrayed has been used as an exposure system for forming a latent image corresponding to an image on a photosensitive member. This exposure apparatus has an advantage that it is relatively small and a quiet image forming apparatus can be easily configured.

The light emitting elements of such an exposure apparatus are constituted by light emitting diodes or the like, and these light emitting elements emit diffused light from a certain point or a certain surface.
Therefore, in order to form a latent image on the photoreceptor, it is necessary to form the diffused light emitted from the light emitting element into minute spots. Therefore, many exposure apparatuses are provided with an imaging element array represented by a rod lens array.

[0004]

However, most of the above-described imaging element arrays used in the conventional exposure apparatus collect only a small part of the light diffused from the light emitting element. The amount of light to be exposed is considerably smaller than the total amount of light emitted from the light emitting element. On the other hand, image forming apparatuses have been required to operate at higher speeds in recent years. If an attempt is made to increase the speed of image formation, the exposure time of light from the light emitting element becomes shorter, so that a good latent image may not be obtained. is there. Furthermore, the image forming apparatus is required to be as small as possible, and accordingly, the exposure apparatus, which is a component in the apparatus, is also required to be downsized.

The present invention has been made in view of the above points, and has as its object to reduce the exposure time, to enable high-speed image output of an image forming apparatus in which an exposure device is incorporated, and to provide a driver unit. An object of the present invention is to provide a simple and compact exposure apparatus having a small number of signal lines for connecting chips.

[0006]

In order to achieve the above object, the invention of claim 1 has first and second light emitting element rows in which a plurality of light emitting element rows in which a plurality of light emitting elements are arranged are arranged substantially in parallel with each other. A plurality of light emitting element chips arranged in a row, and an image forming means for forming a light beam emitted from the first and second light emitting element rows on a photosensitive member. Forms a drive unit by arranging a large number of light emitting thyristors that can electrically control the threshold voltage or threshold current and connecting neighboring light emitting thyristors to each other with an electric element having a unidirectional voltage or current A light emitting element array that performs self-scanning with a two-phase transfer clock, wherein the first and second light-emitting element arrays commonly use the two-phase transfer clock.

The means for branching the two-phase transfer clock to each of the drive units of the first and second light emitting element arrays may be provided in the light emitting element chip.

[0008] The invention of claim 8 is to arrange a plurality of light emitting element chips having first and second light emitting element rows in which a plurality of light emitting element rows in which a plurality of light emitting elements are arranged are arranged substantially in parallel with each other.
In an exposure apparatus having an image forming means for forming an image of a light beam emitted from a second light emitting element array on a photoreceptor, each of the first and second light emitting element arrays electrically controls a threshold voltage or a threshold current. A driving unit is formed by arranging a large number of light-emitting thyristors that can be controlled in parallel and connecting the neighboring light-emitting thyristors to each other by an electric element having a unidirectional voltage or current.
This is a light-emitting element row that performs self-scanning by a phase transfer clock, and is characterized in that a power supply line required for a light-emitting operation is commonly used in the first and second light-emitting element rows.

Further, the means for branching the power supply line to the respective drive units of the first and second light emitting element arrays may be formed in the light emitting element chip.

A thirteenth aspect of the present invention is to arrange a plurality of light emitting element chips having first and second light emitting element rows in which a plurality of light emitting element rows in which a plurality of light emitting elements are arranged are arranged substantially in parallel with each other. An image forming means for forming a light beam emitted from the second light emitting element array on a photoreceptor, wherein each of the first and second light emitting element arrays outputs a threshold voltage or a threshold current. A large number of light-emitting thyristors that can be controlled in a row are arranged, and neighboring light-emitting thyristors are connected to each other by an electric element having a unidirectional voltage or current to form a driving unit. Self-scanning is performed by a two-phase transfer clock. This is a light emitting element row to be performed, and a start clock line for starting transfer is commonly used in the first and second light emitting element rows.

Further, the means for branching the start clock line to the driving units of the first and second light emitting element arrays may be formed in the light emitting element chip.

The distance d between the light emitting element rows in the direction perpendicular to the row direction of the two light emitting element rows is different from the light emitting element row direction when the photosensitive member is exposed using the light emitting element rows. Let P be the vertical resolution pitch and N be an odd number (1, 3, 5,...)

[0013]

## EQU4 ## The configuration may be such that d = P × N.

Alternatively, a transfer clock for the two light emitting element rows and a power supply line necessary for a light emitting operation are commonly used.

Alternatively, a transfer clock for the two light emitting element arrays and a start clock line for starting transfer are commonly used.

Alternatively, a power supply line necessary for the light emitting operation of the two light emitting element arrays and a start clock line for starting transfer are commonly used.

Alternatively, a transfer clock for the two light emitting element arrays, a power supply line necessary for a light emitting operation, and a start clock line for starting transfer are commonly used.

In the present invention, by providing two light emitting element arrays in the light emitting element chip, the time for exposing an image can be shortened, and the transfer clock, power supply, or start clock is shared by the two light emitting element arrays. Or, by sharing each combination, a simpler and smaller exposure apparatus can be obtained.

[0019]

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

<First Embodiment> A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows an equivalent circuit of two light emitting element rows in a self-scanning light emitting element chip having a thyristor structure constituting an exposure apparatus of the present invention. FIG. 2 shows a configuration of a control unit of the plurality of self-scanning light emitting element chips. FIG. 3 shows the details of the driver unit and the buffer unit of the control unit of the self-scanning light emitting element chip. FIG.
Indicates a state in which image data is stored in the buffer unit. FIG. 5 schematically shows the positional relationship between the light emitting element chip, the photosensitive drum, and the image forming element row.

First, the light emitting element of this embodiment will be described. The exposure apparatus of the present invention includes two light emitting element arrays arranged substantially in parallel with each other, and the light emitting element arrays are configured by arranging self-scanning light emitters having a thyristor structure. Hereinafter, the operation principle and control of the light emitting element array will be described.

FIG. 1 is a diagram showing an equivalent circuit of two light emitting element rows in a self-scanning light emitting element chip having a thyristor structure according to the present invention. 1013, 1033, 2013
Is the load resistance, 1034, 1036, 1044, 104
Reference numerals 6, 2034, 2036, 2044 and 2046 are thyristors.

The operation of the first light emitting element row in FIG. 1 will be described as an example. The gate terminals of the thyristors 1034 and 1036 are connected to each other via a diode 1035, and are connected to a power supply VGA via a load resistor 1033. It is connected. On the other hand, transfer clocks φ1 and φ2 for the transfer operation are applied to the cathodes of the thyristors 1034 and 1036. Assuming that the thyristor 1034 is now turned on by the transfer clock of Φ1, the gate potential of the thyristor 1034 becomes almost zero volts, and this potential affects the element on the right side of the drawing through the diode.

Only the elements on the right side of the drawing are selectively turned on by the next transfer clock Φ2, so that the transfer on the right side of the drawing becomes possible. With the above operation, 1036
Are simultaneously addressed and a DATA clock corresponding to the image information is applied from the DATA <A> line, whereby the 1036 thyristors emit light.

By repeating the above operation, a predetermined thyristor can emit light in accordance with image data. This is the operation of the light emitting unit 1001 of the first light emitting element array, but the light emitting unit 2001 of the second light emitting element array is also
By the same operation as above, the DATA clock is set to DATA <B
> Emit light by applying from the line.

However, the light emitting section 20 of the second light emitting element row
01 and the power supply VGA are 1
It is configured to be shared with the light emitting unit 1001 in the column. Therefore, the transfer speeds of these two rows of light emitting units are accurately matched by sharing the transfer clocks Φ1 and Φ2. Further, transfer clocks Φ1, Φ2 and power supply VGA
, The number of signal lines from the driver unit to the light emitting element chip can be reduced, and the configuration of the device is simplified, which contributes to downsizing.

Further, the transfer start timing of each of the light emitting units 1001 and 2001 is started by the clock of ΦSA and ΦSB, respectively.
It is possible to shift the light emission start timing of 01.

FIGS. 2 and 3 show the structure of the control unit of the luminous body according to the present invention. 101A and 101B denote the luminous element arrays of the first luminous element chip, 201A and 201B, respectively.
Indicates a light emitting element array of the second light emitting element chip. Reference numeral 2101 denotes a driver unit and a buffer unit of the light emitting array, 2201 denotes a buffer unit corresponding to each light emitting element chip, 2203 denotes a data distribution unit, 2202
Denotes an image data storage unit. The driver and buffer unit 2101 of the light emitting array includes a buffer unit 2201 and a data distribution unit 2203.

FIG. 4 shows image data stored in the image data storage section 2202, where A1 to A127 are image data to be printed (also referred to as printing or printing) by the first light emitting element chip in the first column. , A128 to A255 are 1
Image data to be printed by the second light emitting element chip in the column, and B1 to B127 indicate image data to be printed by the first light emitting element chip in the second column. These image data are distributed to a buffer unit 2201 corresponding to each light emitting element chip by a data distribution unit 2203, a necessary clock is added as described above, and the data is transferred to each light emitting element chip together with a print data clock.

When the exposure apparatus having the above configuration is incorporated in an image forming apparatus, the light emitting element chip 101 having the two light emitting element rows 101A and 101B is mounted on the photosensitive drum 2 as schematically shown in FIG. They are installed so as to face each other, and the imaging element array 3 is arranged between them. Light emitting element row 101
The divergent light from A and 101B forms an image as a fine spot on the photosensitive drum 2 by the imaging element array 3. The imaging element array 3 includes, for example, a plurality of rod lenses, and is accurately positioned between the light emitting element chip 101 and the photosensitive drum 2 so as to satisfy the imaging performance. Here, the light emitting element chip 101 has been exemplarily described, but other light emitting element chips in the present embodiment are also arranged in the same manner as described above.

As described above, in this embodiment, since the light emitting element chip is provided with two light emitting element rows, the exposure time can be shortened, and the high speed image output of the image forming apparatus in which the exposure apparatus is incorporated. In addition, the transfer clocks Φ1 and Φ2 and the power supply VGA are shared by the two light emitting element arrays, so that the transfer speeds of the two light emitting element arrays match exactly, and the signal line connecting the driver unit and the chip is provided. , A simple and small-sized exposure apparatus can be provided.

<Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 6 shows an equivalent circuit of two light emitting element rows in a self-scanning light emitting element chip having a thyristor structure constituting the exposure apparatus of the present embodiment, and FIG. 7 shows control of a plurality of light emitting element chips of the present embodiment. FIG. 8 schematically shows a positional relationship between a light emitting element chip, a photosensitive drum, and an image forming element array.

First, the light emitting element of this embodiment will be described. In the exposure apparatus of the present embodiment, as in the first embodiment, the light emitting section of the exposure apparatus is formed by arranging a plurality of light emitting element chips each having two light emitting element rows arranged substantially in parallel with each other. This light-emitting element array is configured by arranging thyristor-structured self-scanning light-emitting elements. Here, a portion such as a data array in the data memory of the light emitting element row is the same as that of the first embodiment, and the description thereof will be omitted. Hereinafter, the operation principle and control of the light emitting element array will be described.

In the equivalent circuit shown in FIG. 6, reference numeral 3001 denotes a light emitting unit in the first column; 4001, a light emitting unit in the second column;
033 and 4033 are load resistances, 3034, 3036 and 3
044, 3046, 4034, 4036, 4044, 4
046 are thyristors.

The operation of the first light emitting element column will be described as an example. The gate terminals of the thyristors 3034 and 3036 are connected to each other via a diode 3035 and to the power supply VGA via a load resistor 3033. You. On the other hand, the transfer clock Φ for the transfer operation
1, Φ2 is applied to the cathode. Now thyristor 30
Assuming that 34 is turned on by the transfer clock .PHI.1, its gate potential will be substantially zero volts, which will affect the element to the right in the drawing through the diode. Only the elements in the right direction of the drawing are selectively turned on by the next transfer clock Φ2, so that the transfer in the right direction of the drawing becomes possible. At the same time as addressed above,
The DATA clock corresponding to the image information is set to DATA <A>
By applying from the line, the thyristor 3036 emits light.

By repeating the above operation, a predetermined thyristor can emit light in accordance with image data.
The above is the operation of the light emitting section 3001 of the first light emitting element row. The light emitting section 4001 of the second light emitting element row also emits light by the same operation as described above.

However, the light emitting section 40 of the second light emitting element row
01, the transmission clocks Φ1, Φ2, the power supply VGA, and the start clock ΦS correspond to the light emitting units 30 of the first light emitting element column.
01 is shared. Therefore, the transfer speeds of these two light emitting units are exactly the same by sharing the transfer clocks Φ1 and Φ2. In addition, by sharing the start clock ΦS, the two light emitting element lines are simultaneously transferred. To start. Further, the transfer clock Φ
By sharing 1, Φ2, the power supply VGA and the start clock ΦS, the number of signal lines from the driver unit to the light emitting element chip can be reduced, and the configuration of the device is simplified.

FIG. 7 shows the configuration of a control unit for a plurality of light emitting element chips according to this embodiment.
Are the light emitting element rows of the first light emitting element chip, 12
01A and 1201B are light emitting element arrays of the second light emitting element chip, respectively. Reference numeral 4101 denotes a driver unit and a buffer unit of the light emitting array.

As described above, the signal lines from the driver unit to each light emitting element chip are VGA, ΦS, Φ1, Φ
2 and only data lines to each light emitting element chip. In addition, a portion related to the distribution of data to the two light emitting element rows such as the buffer section is the same as that of the first embodiment, and thus the description thereof is omitted.

When the exposure apparatus of this embodiment is incorporated into an image forming apparatus, as shown schematically in FIG. 8, a light emitting element chip 1 having two light emitting element rows 1101A and 1101B is used.
101 is installed so as to face the photosensitive drum 5002, and an imaging element array 5003 is arranged between them. The divergent light from the light emitting element arrays 1101A and 1101B is imaged as fine spots on the photosensitive drum 5002 by the imaging element array 5003. The imaging element array 5003 includes, for example, a plurality of rod lenses, and
1 and the photosensitive drum 5002 are accurately positioned so as to satisfy the imaging performance.

Here, the light emitting element arrays 1101A and 1101A
The distance d of B is the same as the pixel pitch used for image formation, and since the transfer clock and the start clock are shared by the light emitting element arrays 1101A and 1101B as described above, the light emitting element arrays 1101A and 1101B emit light simultaneously. And the transfer speed is the same, so that the interval between the latent image lines drawn by the light emitting element arrays 1101A and 1101B becomes the same as the pixel pitch.

Here, the light emitting element chip 1101 has been exemplarily described, but the other light emitting element chips in the exposure apparatus of the present embodiment are arranged in exactly the same manner.

As described above, according to the present embodiment,
By providing two light emitting element rows in the light emitting element chip, the exposure time can be shortened, high-speed image output of an image forming apparatus in which the exposure apparatus is incorporated is enabled, and transfer clocks Φ1 and Φ2 are provided by the two light emitting element rows. , The power supply VGA and the start clock ΦS are shared, so that the transfer speeds of the two light emitting element rows exactly match and the transfer start of the two light emitting element rows exactly match, and the driver unit and the chip are connected. Therefore, a small-sized exposure apparatus having a simple configuration with a small number of signal lines can be provided.

[0044]

As described above, according to the present invention,
Since the light emitting element chip is provided with two light emitting element rows, the exposure time can be shortened, high-speed image output of an image forming apparatus in which the exposure apparatus is incorporated is enabled, and transfer is performed using two light emitting element rows. Clock Φ1, Φ2 or power supply V
By sharing the GA or the start clock ΦS, or by sharing the respective combinations, a simple and small exposure apparatus with a small number of signal lines connecting the driver unit and the chip can be provided.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an equivalent circuit of two light emitting element columns in a self-scanning light emitting element chip having a thyristor structure according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a control unit of a plurality of self-scanning light emitting element chips of FIG. 1;

FIG. 3 is a block diagram showing a configuration of a driver unit and a buffer unit of a control unit of the self-scanning light emitting element chip of FIG. 2;

FIG. 4 is a memory map showing a state where image data is stored in a buffer unit of FIG. 3;

FIG. 5 is a perspective view schematically showing a positional relationship between a light emitting element chip, a photosensitive drum, and an image forming element row according to the first embodiment of the present invention.

FIG. 6 is a circuit diagram showing an equivalent circuit of two light emitting element columns in a self-scanning light emitting element chip having a thyristor structure according to a second embodiment of the present invention.

7 is a block diagram illustrating a configuration of a control unit of a plurality of light emitting element chips of FIG. 6;

FIG. 8 is a perspective view schematically showing a positional relationship between a light emitting element chip, a photosensitive drum, and an image forming element row according to a second embodiment of the present invention.

[Explanation of symbols]

2,5002 Photosensitive drum 3,5003 Imaging element array 101, 1101 Light emitting element chips 101A, 201A, 1101A, 1201A First light emitting element array 101B, 201B, 1101B, 1201B in each light emitting element chip The second row of light emitting element rows 1001, 3001 The first row of light emitting sections 2001, 4001 The second row of light emitting sections 1013, 1033, 2013, 2033, 3013,
3033, 4033 Load resistances 1034, 1036, 1044, 1046 Thyristors 2034, 2036, 2044, 2046 Thyristors 3034, 3036, 3044, 3046 Thyristors 4034, 4035, 4036, 4044, 4046
Thyristor 2101, 4101 Driver and buffer of light emitting array 2201 Buffer corresponding to each light emitting element chip 2202 Image data storage 2203 Data distribution

Claims (18)

[Claims] 1. A light-emitting element chip having first and second light-emitting element rows in which a plurality of light-emitting element rows in which a plurality of light-emitting elements are arranged are arranged substantially in parallel with each other, and the first and second light-emitting element rows are arranged. An exposure apparatus comprising an image forming means for forming an image of a light beam emitted from a light-receiving element on a photosensitive member, wherein each of the first and second light-emitting element arrays emits light capable of electrically controlling a threshold voltage or a threshold current. A light-emitting element array in which a number of thyristors are arranged, and neighboring light-emitting thyristors are connected to each other by an electric element having a unidirectional voltage or current to form a driving unit and perform self-scanning by a two-phase transfer clock. An exposure apparatus, wherein the two-phase transfer clocks are commonly used in the first and second light emitting element arrays. 2. The exposure apparatus according to claim 1, wherein the means for branching the two-phase transfer clock to each drive unit of the first and second light emitting element arrays is configured in the light emitting element chip. An exposure apparatus characterized by the above-mentioned. 3. The exposure apparatus according to claim 1, wherein a power supply line required for a light emitting operation of the two light emitting element arrays is commonly used. 4. The exposure apparatus according to claim 3, wherein the means for branching the power supply line to a driving section of the first and second light emitting element columns is formed in the light emitting element chip. Exposure equipment. 5. The exposure apparatus according to claim 1, wherein a start clock line for starting transfer of the two light emitting element arrays is commonly used. 6. The exposure apparatus according to claim 5, wherein the means for branching the start clock line to a driving section of the first and second light emitting element columns is formed in the light emitting element chip. Exposure equipment. 7. The exposure apparatus according to claim 1, wherein the two light emitting element columns are arranged in a direction perpendicular to a column direction of the two light emitting element columns.
When the distance d between the two light emitting element rows is P, the resolution pitch in the direction perpendicular to the light emitting element row direction when exposing the photosensitive member using the light emitting element rows is P, and N is an odd number (1, 3, 5,
..) Where d = P × N. 8. A plurality of light emitting element chips having first and second light emitting element rows in which a plurality of light emitting element rows in which a plurality of light emitting elements are arranged are arranged substantially in parallel with each other, and the first and second light emitting element rows are arranged. An exposure apparatus comprising an image forming means for forming an image of a light beam emitted from a light-receiving element on a photosensitive member, wherein each of the first and second light-emitting element arrays emits light capable of electrically controlling a threshold voltage or a threshold current. A light-emitting element array in which a number of thyristors are arranged, and neighboring light-emitting thyristors are connected to each other by an electric element having a unidirectional voltage or current to form a driving unit and perform self-scanning by a two-phase transfer clock. An exposure apparatus, wherein a power supply line required for a light emitting operation is commonly used in the first and second light emitting element arrays. 9. The exposure apparatus according to claim 8, wherein the means for branching the power supply line to each of the drive units of the first and second light emitting element columns is formed in the light emitting element chip. Exposure apparatus. 10. The exposure apparatus according to claim 8, wherein a start clock line for starting transfer of the two light emitting element arrays is commonly used. 11. The exposure apparatus according to claim 10, wherein the means for branching the start clock line to a driving section of the first and second light emitting element columns is formed in the light emitting element chip. Exposure equipment. 12. The exposure apparatus according to claim 8, wherein the two light emitting element columns are arranged in a direction perpendicular to a column direction of the two light emitting element columns.
When the distance d between the two light emitting element rows is P, the resolution pitch in the direction perpendicular to the light emitting element row direction when exposing the photosensitive member using the light emitting element rows is P, and N is an odd number (1, 3, 5,
..) Where d = P × N. 13. A plurality of light emitting element chips having first and second light emitting element rows in which a plurality of light emitting element rows in which a plurality of light emitting elements are arranged are arranged substantially in parallel with each other, and the first and second light emitting element rows are arranged. An exposure apparatus comprising an image forming means for forming an image of a light beam emitted from a light-receiving element on a photosensitive member, wherein each of the first and second light-emitting element arrays emits light capable of electrically controlling a threshold voltage or a threshold current. A light-emitting element array in which a number of thyristors are arranged, and neighboring light-emitting thyristors are connected to each other by an electric element having a unidirectional voltage or current to form a driving unit and perform self-scanning by a two-phase transfer clock. An exposure apparatus, wherein a start clock line for starting transfer is commonly used in the first and second light emitting element arrays. 14. The exposure apparatus according to claim 13, wherein the means for branching the start clock line to a driving section of the first and second light emitting element columns is formed in the light emitting element chip. Exposure equipment. 15. The exposure apparatus according to claim 13, wherein the means for branching the two-phase transfer clock to each of the driving units of the first and second light emitting element arrays is configured in the light emitting element chip. An exposure apparatus characterized by the above-mentioned. 16. The exposure apparatus according to claim 13, wherein a power supply line necessary for a light emitting operation of the two light emitting element arrays is commonly used. 17. The exposure apparatus according to claim 16, wherein the means for branching the power supply line to a drive section of the first and second light emitting element columns is formed in the light emitting element chip. Exposure equipment. 18. The exposure apparatus according to claim 13, wherein the two light emitting element columns are arranged in a direction perpendicular to a column direction of the two light emitting element columns.
When the distance d between the two light emitting element rows is P, the resolution pitch in the direction perpendicular to the light emitting element row direction when exposing the photosensitive member using the light emitting element rows is P, and N is an odd number (1, 3, 5,
..) Where d = P × N.