JP2001213000A - Imaging apparatus and method for correcting quantity of light of imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus in which exposure is performed while dealing with lowering in the quantity of light due to the lighting rate of array-like light emitting elements for exposing an image carrier. SOLUTION: The imaging apparatus arranged with array-like light emitting elements 12 for exposing an image carrier 10 by emitting light comprises monitor light emitting elements 13 emitting light at a plurality of lighting rates, i.e., the rate of current per time, while keeping a constant lighting rate, means 15 for detecting the quantity of light emitted from the monitor light emitting elements at a plurality of lighting rates, and means for controlling the quantity of light emitted from the array-like light emitting elements wherein the controller can correct the quantity of light emitted from the array-like light emitting elements based on the quantity of light detected by the detecting means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer, and the like, which form an image by arranging light emitting elements such as light emitting diodes in an array on an image carrier. And a method for controlling the light quantity of the light emitting element.

[0002]

2. Description of the Related Art A large number of light-emitting elements such as light-emitting diodes in an array emit light to form an electrostatic latent image by exposing it to an image carrier, develop the latent image, transfer the latent image to a sheet, and heat the latent image. 2. Description of the Related Art An image forming apparatus for forming an image on a sheet by a configuration for performing fixing is conventionally known. In the image forming apparatus having such a configuration, the charge amount of the electrostatic latent image changes due to the variation in the light amount of the light emitting element, and the density of the formed image is disturbed. For this reason, the amount of light of the light emitting element is an important factor that determines the quality of an image to be formed.

[0003] The light quantity of the light emitting element is determined by the magnitude of the current to be supplied. The light quantity also changes depending on the environment in which the apparatus is installed or the temperature change due to the heat source of the member for performing the heat fixing. For this reason, the amount of current supplied to the light emitting element cannot be kept constant by simple constant current control using an open loop. Therefore, it has been proposed that a conventional image forming apparatus that requires a stable light amount monitors the light amount of the light emitting element and corrects the light amount by changing a current supplied so as to obtain a desired light amount. .

FIG. 1 is a schematic diagram in which an array-shaped light emitting element for performing exposure is arranged on an image carrier of a conventional image forming apparatus. A control unit (not shown) supplies an electric current to the light emitting elements 12 in an array to emit light, and forms an electrostatic latent image on the image carrier 10. A mirror 75 is provided outside the area of the image carrier 10 where the latent image is formed, and guides the light of the light emitting elements 12 in an array to the detection means 15. The control means
Before the electrostatic latent image is formed, the array-shaped light emitting elements 12 are forcibly made to emit light, the amount of light detected by the detection means 15 is monitored, and the current supplied based on the monitored amount of light of the array-shaped light emitting elements 12 To correct the amount of light. For this reason, even if the ambient temperature changes, the light quantity of the array-like light emitting elements 12 is kept constant.

[0005]

However, in the above-described conventional configuration, no consideration is given to a decrease in the amount of light due to heat generated by the light emitting element itself. A light emitting element such as a light emitting diode is formed of a semiconductor. When a current supplied to emit light flows through a resistance of a junction inside the semiconductor, the junction generates heat, the temperature rises, the luminous efficiency decreases, and the light intensity decreases. Decrease. Here, a decrease in the amount of light due to heat generation of the light emitting element will be described below.

The density of an image forming an image on a sheet is determined by the amount of light emitted from the light emitting elements exposed on the image carrier, and the amount of light exposed depends on the time for supplying the current supplied to the light emitting elements or the magnitude of the supplied current. Change. The heat generated by the light emitting element itself is proportional to the amount of current supplied. Therefore, a lighting rate which is a ratio of a current per time is used as an amount of the supplied current. As a reference of the ratio of the current per hour, for example, when the rated current of the light emitting element is continuously supplied, 10
0%.

FIG. 2 shows current on the vertical axis and time on the horizontal axis.
5A is a schematic diagram of a waveform of a pulse current supplied to a light emitting element that exposes an image carrier, wherein FIG. 6A is a waveform in which the current I is made constant while the current I flows, and FIG. Is a waveform obtained by changing the current. Here, the current I is the rated current of the light emitting element, and T is the cycle of the pulse current. In the figure, the lighting rates are 90% for a, 50% for b, and 10% for c.
It is. If the lighting rates are the same, the amount of supplied current is the same in both (A) and (B). Since the current supply is more time efficient in (A), it is generally widely used in controlling the light amount of the light emitting element by a pulse waveform.
The lighting rate of (A) is called a duty ratio.

FIG. 3 shows the light quantity on the vertical axis and the time on the horizontal axis.
3 is an example of a light amount detected by a detection unit when the light emitting element emits light by supplying the pulse current of FIG. 2 for a predetermined time. A characteristic in which the amount of light of the light emitting element changes due to heat generated by the light emitting element itself due to the supplied current is called a droop characteristic. In the figure, the maximum value of the light quantity at each lighting rate is P1, and the minimum value is P1.
As 4, the droop ratio, which is an index of the droop characteristic, is defined below.

Droop ratio = (P1-P4) / P4 The droop ratio changes depending on the lighting rate, and particularly, the period T of the pulse current increases when the period T is longer than several tens of milliseconds.

FIG. 4 shows the ratio of the change of the droop ratio at each lighting rate shown in FIG. 3A on the vertical axis and the elapsed time on the horizontal axis. , The rate of change of the droop ratio of each lighting rate over time. In the figure, the lighting rate is 90% for a and 50 for b.
% And c are 10%. In the light emitting device, the amount of heat generated by the light emitting device itself increases in proportion to the amount of the supplied current, the decrease in the amount of light gradually increases, and the droop ratio increases. Therefore, the increase in the droop ratio is greater as the lighting rate of the light emitting element is higher.

An object of the present invention is to provide an image forming apparatus capable of performing stable exposure in view of the above problems.

[0012]

The above object is achieved by the following means.

(1) In an image forming apparatus provided with an array of light emitting elements for emitting light and exposing light to an image carrier, a plurality of lighting rates, which is a rate of current per time, is kept constant. A monitor light-emitting element that emits light at a plurality of light-emitting elements, a detector that detects light amounts of a plurality of lighting rates emitted by the monitor light-emitting element, and a controller that controls the light amount of the array-like light-emitting elements. And (c) correcting the light quantity of the light emitting elements in the array based on the light quantity detected by the detection means.

(2) The image forming apparatus according to (1), wherein the correction of the light amount of the light emitting elements in an array is performed for each scanning line to be exposed or for each sheet on which an image is formed.

(3) The image forming apparatus according to (1) or (2), wherein the monitor light emitting element is integrated with the array light emitting element.

(4) The image forming apparatus according to (1) or (2), wherein the monitor light emitting element is a part of the array light emitting element.

(5) In a method for correcting the amount of light of an image forming apparatus in which an array of light emitting elements for emitting light and exposing light to an image carrier, a lighting rate, which is a ratio of current per time, is kept constant. A monitor light-emitting element that emits light at a plurality of lighting rates, a detecting unit that detects the light amount of the plurality of lighting rates emitted by the monitor light-emitting element, and a light amount of the plurality of lighting rates detected by the detecting unit. A memory for storing a calculated value of the decrease in the light amount of the array-shaped light emitting elements, and correcting the light amount by changing the lighting rate of the array light-emitting elements based on the value stored in the memory. Correction method for the light amount of the image forming apparatus to be controlled in a timely manner.

(6) The method according to (5), wherein the calculation of the decrease in the light amount of the light emitting elements in the array is performed for each sheet on which an image is formed.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 5 is a schematic diagram showing the configuration of the image forming apparatus 1. 1, an image forming apparatus 1 includes an automatic document feeder (ADF) A and a document image reading unit B for reading an image of a document fed by the automatic document feeder.
And an image processing means C for encoding the read document image and processing the data, and a light emitting element comprising a plurality of light emitting diodes arranged in an array for the image carrier 10 comprising a photosensitive drum. A light emitting element 12 of
Control means D for supplying a pulse current to the light emitting elements 12 in an array;
4, an image forming unit E including a developing unit 16 and a cleaning member 21 for forming a toner image on the image carrier 10
And sheet feeding units 22 and 24 for storing sheets P for image formation (hereinafter referred to as sheets), and a reversing path 25 for reversing the front and back of the sheets.

The automatic document feeder A includes a document table 27
And a document transport processing unit 28 including a roller group including the roller R1 and a switching unit (without a reference symbol) for appropriately switching a document moving path. The original image reading unit B is located under the top glass G, and includes two mirror units 30 and 31 that can reciprocate while maintaining the optical path length, a fixed imaging lens 33, an image sensor 35, and the like.

First, a process for forming an image on a sheet will be described. One of the originals (not shown) placed on the original placing table 27 is transported in the original transport processing unit 28, passes under the roller R1, and moves to the mirror units 30, 31 at the fixed position and An image is formed on the image sensor 35 via the lens 33 and read. The read image information of the document is processed by the image processing means C and stored in the image memory as encoded image data.

A monitor light emitting element 1 is provided around the image carrier 10.
3 and a detecting means 15 for detecting the light amount of the monitor light emitting element. The control unit D calculates a decrease in the light amount of the light emitting elements 12 in an array based on the light amount detected by the detection unit 15 and, based on the calculated result, the lighting rate of the pulse current supplied in accordance with the image data stored in the image memory. Change
The light amount of the light emitting elements 12 in an array is corrected. Control means D
Causes the array-shaped light emitting elements 12 to emit light with the corrected light amount, and is exposed onto the image carrier 10 through the imaging lens 17. The imaging lens 17 is a SELFOC lens array that prevents diffusion of light emitted by the light emitting elements 12 in an array.

Prior to exposure, the image carrier 10 rotating in the direction of the arrow (counterclockwise) is given a predetermined surface potential by the corona discharge action of the charger 14. By the exposure of the light emitting elements 12 in the array, the potential of the exposed portion is reduced according to the amount of the exposed light, and an electrostatic latent image corresponding to the image data is formed on the image carrier 10. The electrostatic latent image is reversely developed by the developing device 16 and becomes a visible image (toner image).

On the other hand, the symbol S in the paper feeding unit 22
Is always urged by a biasing means such as a coil spring (not shown).
The free end is a movable plate which is urged upward, and the uppermost sheet P comes into contact with the feed roller 50. The sheet P that has come into contact with the feed roller 50 is sent out from the paper feed unit 22 and sent out to a pair of rotatable rollers, a drive roller 51 and a driven roller 52.
The driving roller 51 rotates to separate the sheets P one by one and conveys the sheets P toward the loop forming roller 57. The loop forming roller 57 is provided on the upstream side of the registration roller 56 when viewed from the sheet conveying direction.
The sheet P is conveyed and the leading edge of the sheet is brought into contact with the registration roller 56 before the rotation is started to form a loop of the sheet P. Thereafter, the registration roller 56 starts rotating in synchronization with the toner image formed on the image carrier 10 and conveys the sheet P. The toner image of the image carrier 10 overlaps the sheet P conveyed in synchronization with the image carrier 10, and the toner image is transferred to the sheet P by the urging of the transfer device 18. After the sheet P is separated from the image carrier 10 by the bias of the separation electrode 20, the toner powder for forming the toner image is melted and fixed on the sheet P by the action of pressing and heating of the fixing roller H having a heat source. Is done. The sheet P on which the toner image has been fixed is discharged onto a discharge tray T via a discharge roller 79.

The conveyance of the sheet from the paper feeding unit 24 is as follows.
The feeding roller 5 includes the following rollers having the same function as the roller that has conveyed the sheet P of the sheet feeding unit 22.
3. A pair of rollers, a driving roller 54 and a driven roller 5
5. The registration roller 56 is formed by the loop forming roller 58.
Conveyed toward.

The manual feed unit 26 includes a manual tray 60 on which sheets are placed, and can be opened and closed with respect to the main body side wall of the image forming apparatus 1 using the lower end as a fulcrum. Similarly to the sheet feeding unit 24, the sheet feeding from the manual sheet feeding unit 26 includes the following rollers having the same function, and includes a feed roller 61, a pair of a driving roller 63 and a driven roller 65, and a loop. The sheet is conveyed toward the registration roller 56 by the creation roller 59.

When forming images on both sides of the sheet P,
In the image forming process, the branch guide 90 is positioned at a position indicated by a broken line in the figure so as to feed the sheet P having the toner image transferred onto the first surface to the conveyance path 80. Is controlled via a control unit (not shown) so as to take the solid line position. The conveyance path 80 draws a gentle arc, and ensures smooth movement of the sheet P. The sheet P that has descended after passing through the conveyance path 80 traverses the conveyance path of the sheet from the manual sheet feeding unit 26,
It reaches the switchback roller R20. The switchback roller R20 is composed of a pair of rollers that can rotate forward and reverse, and a predetermined distance between the bottom (the same as the bottom wall) of the paper feed tray 24 provided below the switchback roller R20 and the bottom wall of the apparatus body. The sheet P is directed to the reversing path 25 having the above space. The leading end of the sheet P that has reached the switchback roller R20 is nipped by the roller, and the roller rotates to rotate the reversing path 25.
It is led to. At this time, the image of the first surface transferred onto the sheet P faces downward. Eventually, the rotation is stopped with the switchback roller R20 sandwiching the rear end of the sheet P. Thereafter, when rotation starts in the reverse direction, the sheet P
The loop forming roller 58 provided corresponding to the sheet feeding unit 24 is in a state where the front and back are reversed in the reversing path 25, that is, in a state where the second surface on which the image is not transferred is directed to the image carrier 10 side. And passes through the same conveyance path as the sheet from the paper feed unit 24, and the leading end of the sheet P is applied to the registration roller 56 before rotation starts to form a loop. On the other hand, a second toner image is formed on the image carrier 10, and the registration rollers 56
The rotation of the sheet P is started in synchronization with the toner image formed on the sheet P, and the looped sheet P is conveyed. The toner image of the image carrier 10 overlaps the second surface of the sheet P conveyed in synchronization with the image carrier 10, and the toner image is transferred to the sheet P by the urging of the transfer device 18. Thereafter, fixing processing is performed, and the sheet P
Is discharged onto a paper discharge tray T via a paper discharge roller 79.

Next, a method for correcting the light amount of the light emitting elements 12 in an array according to the present invention will be described in detail.

FIG. 6 is a schematic diagram in which an array of light emitting elements 12 for performing image exposure is arranged on the image carrier 10. In the figure, the monitor light emitting element 13 is
a, a plurality of light emitting elements a, b, c, and a plurality of photodiodes a, b, c for detecting the amount of light of each of the plurality of light emitting elements of the monitor light emitting element through the imaging lens 17. It has. The monitor light emitting element 13 and the detecting means 15
An array-shaped light emitting element 12 and an image carrier 10 for performing exposure,
The light-emitting elements 12 are provided at substantially the same intervals and are close to the exposure conditions of the light-emitting elements 12 in an array. If the monitor light emitting element 13 is connected to and integrated with the light emitting element 12 in an array, the distance accuracy is further improved, which is preferable.

The control means D sets the monitor light emitting element 13 at a predetermined timing to a plurality of lighting rates, for example, a lighting rate of 10%,
A constant pulse current of 50% and 90% is supplied to emit light. The control means D calculates a decrease in the light amount of the array-like light-emitting elements 12 based on the detection result of the detection means 15 which has detected the light amount of the monitor light-emitting element 13 and changes the lighting rate of the supplied pulse current according to the image data. Thus, the light amount of the light emitting elements 12 in the array is corrected. The monitor light-emitting element 13 and the array-shaped light-emitting element 12 for exposure use the same light-emitting element member or a light-emitting element member having a correlation with the temperature characteristic and the droop characteristic to facilitate the calculation of the decrease in the light amount. Further, when the array-shaped light emitting elements 12 are disposed outside the image formed on the image carrier 10 and a part thereof is used as a monitor light emitting element, the monitor light emitting element 13 performs light exposure. 12 is preferable because it becomes the same light emitting element and the calculation accuracy of the decrease in the light amount is improved.

The control means D causes the array-shaped light-emitting elements 12 to emit light at an amount of light obtained by correcting the lighting rate of the above-described image data for each scanning line in the width direction X of the array-shaped light-emitting elements 12 and to rotate the rotating image. The carrier 10 is exposed to form a latent image. Exposure for each scanning line may be performed for each line or for a plurality of lines at the same time, depending on the arrangement of the light emitting elements 12 in an array. The monitor light emitting element 13 emits light at a predetermined lighting rate while the array light emitting element 12 emits light, and obtains a droop characteristic according to an operation time in an environment in which the image forming apparatus is installed to obtain the calculation accuracy of the light quantity reduction. Have improved.

FIG. 7 shows an example of a method of correcting the amount of light by the control means D. In the figure, the horizontal axis represents the lighting rate of the monitor light emitting element 13 and the vertical axis represents the light quantity, and the characteristic A is a design value of the light quantity with respect to the lighting rate of the arrayed light emitting elements 12 of the image forming apparatus. At predetermined timing, for example, the control unit D detects the light emission of each of the plurality of lighting rates X1, X2, X3 of the monitor element 13 by the light amount a, b,
Based on c, a characteristic B, which is a decrease in the amount of light of the light emitting elements 12 in the array, is calculated, and the calculated characteristic B is stored in the memory. The control unit D reads out the characteristic B stored in the memory before performing image formation. For example, when forming an image, the control unit D changes the lighting rate Y1 of the pulse current supplied according to the image data to the lighting rate Y2 based on the characteristic B, and changes the light amount d of the lighting rate Y1 of the characteristic B to the design value. Lighting rate Y of characteristic A
The light amount e approaches 1. That is, since the control is performed so as to correct the light amount of the array-shaped light emitting elements 12 to be exposed based on the decrease in the light amount of the monitor light emitting elements 13 having the plurality of lighting rates, the exposure corresponding to the decrease in the light quantity corresponding to the lighting rate is performed. Is performed. The number of the lighting rates of the monitor light emitting elements 13 is three in the embodiment, but is not limited to this as long as the decrease in the light quantity with respect to the lighting rate of the array-shaped light emitting elements 12 can be calculated. 2 drops
If it is proportional to a straight line of the following function, it can be calculated from the lighting rates of the two monitor light emitting elements. Further, the change of the lighting rate of the image data performed based on the characteristic B is performed by, for example, setting the resolution to 5
By performing the setting in the unit of%, the change time of the control means D can be reduced.

FIG. 8 shows that the control means D
5 is an example of a flowchart of correction of the light amount of the light emitting elements 12 in an array, which is performed based on the light amount. When the power of the image forming apparatus is turned on, the control unit D detects light amounts of the plurality of lighting rates of the monitor light emitting element 13 detected by the detection unit 15 in step 101, and based on the light amounts detected in step 102, A decrease in the light amount of the array-shaped light emitting elements 12 for a plurality of lighting rates is calculated, and the data on the decrease in the light amount calculated in step 103 is stored in the memory. Step 11
At 0, the data stored in the memory is called before the image formation starts. In step 120, the control unit D changes the lighting rate of the image data formed based on the data for each scanning line, corrects the light amount of the array-shaped light emitting elements 12, and exposes the image carrier 10. In step 130, it is checked whether the exposure is for the last scan line of the image to be formed, and the exposure of the image carrier 10 ends in the sequence of steps 120 to 130.

FIG. 9 is a flowchart for correcting the amount of light of the array of light emitting elements 12 having a different form from that of FIG. FIG.
The same steps as those described above are denoted by the same reference numerals, and description thereof is omitted. In the present embodiment, the calculation of the decrease in the light amount of the array-like light emitting elements based on the detection of the light amount of the monitor light emitting elements 13 is performed for each sheet on which an image is formed. In step 120, the control means D changes the lighting rate of the image data to be formed for each scanning line based on the data, corrects the light amount, and exposes the image carrier 10. In step 135, it is checked whether or not the exposure of the last scan line is performed on the page of the sheet on which the image is formed, and the exposure on the sheet is completed in the sequence from step 120 to step 135. In steps 140 to 142, the control means D detects the light amounts of the plurality of lighting rates of the monitor light emitting element 13 detected by the detection means 15 in step 140, and the light amounts detected in step 141 in the same manner as in steps 101 to 103. , The reduction in the amount of light of the array of light emitting elements 12 for a plurality of lighting rates is calculated, and the data of the reduction in the amount of light calculated in step 142 is stored in the memory. In step 150, the final sheet on which an image is to be formed is checked, and when an image is to be formed on the next sheet, exposure is performed based on the data saved in step 142 in a sequence from step 110 to step 135.

FIG. 10 is an example of a block diagram of a circuit for supplying a pulse current to the array-like light-emitting elements 12 of the control means D. FIG. The circuit (B) changes the amount of light to be exposed according to the magnitude of the current value while keeping the lighting rate of the pulse current constant. In the figure, a control means D includes a control circuit 180, a constant current source 201, a transistor 210, a transistor 220,
It has an inverter 230, a load resistor 202, and a memory 190.

In the circuit (A) having a constant current value, the control circuit 1
80 sends a signal t in which the lighting rate according to the image data is changed according to the value stored in the memory 190 to change the lighting time.
The light amount of the light emitting elements 12 in an array is corrected. If the pulse current of the lighting rate of the signal t is HIGH, the transistor 210 is turned on, and the constant current source 2 is supplied to the array of light emitting elements 12.
A current of 01 flows to emit light. If the level is LOW, the transistor 210 is off and the light emitting elements 12 in the array do not emit light. Therefore, the light amount of the array-like light emitting elements 12 changes depending on the lighting rate of the signal t. Transistor 210
Is off, the transistor 2 is connected via the inverter 230.
20 is turned on, and the current of the constant current source 201 flows through the load resistor 202. Therefore, a constant current I is always supplied from the constant current source.

In the circuit (B) having a constant lighting rate, the circuit configuration for making the array-shaped light emitting elements 12 emit light is the same as that of the circuit (A), but the signal t for changing the emission time is not changed without changing the signal t.
Is sent to the transistors 210 and 220. The control circuit 180 sends to the D / A circuit 200 a signal r for outputting a current for causing the image data to emit light at a lighting rate corrected by the value stored in the memory 190,
The current i of 1 is changed to correct the light amount of the light emitting elements 12 in the array.

[0039]

According to the present invention, there is provided an image forming apparatus in which a light emitting element for exposing an image carrier is corrected to a light amount corresponding to a decrease in light amount due to a lighting rate, and which forms an image with little disturbance in density. .

[Brief description of the drawings]

FIG. 1 is a schematic view showing an arrangement in which an array-shaped light emitting element for performing exposure is arranged on an image carrier of a conventional image forming apparatus.

FIG. 2 is a schematic diagram of a waveform of a pulse current supplied to a light emitting element that exposes an image carrier.

FIG. 3 is an example of a light amount detected by a detection unit when a light emitting element emits light by supplying a pulse current for a predetermined time.

FIG. 4 is a graph showing a change rate of a droop ratio of each lighting rate over time when a pulse current having a constant lighting rate is supplied to a light emitting element.

FIG. 5 is a schematic diagram illustrating a configuration of an image forming apparatus.

FIG. 6 is a schematic diagram in which an array of light emitting elements for performing image dew is provided on an image carrier.

FIG. 7 is an example of a method of correcting a light amount by a control unit.

FIG. 8 is an example of a flowchart of a correction of a light amount of an array of light emitting elements, which is performed by a control unit based on a light amount of a monitor light emitting element.

FIG. 9 is a flowchart of another embodiment for correcting the light amount of the light emitting elements in an array.

FIG. 10 is an example of a block diagram of a circuit for supplying a pulse current to an array of light emitting elements of the control means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Image carrier 12 Array light emitting element 13 Monitor light emitting element 15 Detecting means 17 Imaging lens

Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court II (Reference) G03G 15/043 15/04 (72) Inventor Hiroyuki Maruyama 2970 Ishikawacho, Hachioji-shi, Tokyo Konica Corporation (72) Invention Company Tadayuki Ueda Konica Corporation, 2970 Ishikawa-cho, Hachioji-shi, Tokyo (72) Inventor Ryuji Okutomi Konica Corporation, 2970, Ishikawa-cho, Hachioji-shi, Tokyo (72) Inventor Shinobu Kishi 2970, Ishikawa-cho, Hachioji-shi, Tokyo In-house company (72) Inventor Eiji Nishikawa 2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica Corporation F-term in the company (reference) 2C162 AE28 AF20 AF38 AF84 FA17 FA23 2H027 DA07 DE02 DE07 EA02 EC19 ED06 FD08 ZA07 2H076 AB42 AB51 AB54 AB55 DA04 DA17 DA22 2H110 AA22 AC01 CD18 9A001 KK16 KK32 KK37

Claims (6)

[Claims] An image forming apparatus in which an array of light emitting elements for emitting light and exposing light to an image carrier is provided. A monitor light-emitting element that emits light, a detection unit that detects light amounts of a plurality of lighting rates emitted by the monitor light-emitting element, a control unit that controls the light amount of the array of light-emitting elements,
An image forming apparatus, wherein the control unit corrects a light amount of the array of light emitting elements based on the light amount detected by the detection unit. 2. The image forming apparatus according to claim 1, wherein the correction of the light amount of the array of light emitting elements is performed for each scanning line to be exposed or for each sheet on which an image is formed. 3. The image forming apparatus according to claim 1, wherein the monitor light emitting element is integrated with the array of light emitting elements. 4. The image forming apparatus according to claim 1, wherein the monitor light emitting element is a part of the array light emitting element. 5. A method for correcting the amount of light of an image forming apparatus in which an array of light emitting elements for emitting light and performing exposure is provided for an image carrier, wherein a lighting rate which is a ratio of a current per time is fixed. A monitor light-emitting element that emits light at a plurality of lighting rates; a detecting unit that detects a plurality of light rates of the lighting rates emitted by the monitor light-emitting element; and the array based on the light quantities of the plurality of lighting rates detected by the detecting means. And a memory for storing a calculated value of the decrease in the light amount of the light emitting elements in the shape of an array. Based on the value stored in the memory, the light amount is corrected by changing the lighting rate of the light emitting elements in the array. Correction method for the light amount of the image forming apparatus to be controlled in a timely manner. 6. The method according to claim 5, wherein the calculation of the decrease in the light amount of the array of light emitting elements is performed for each sheet on which an image is formed.