JPH09214697A - Image forming device and its control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration in image quality of a recording image due to thermal interference of adjacent lasers by adjusting plural laser beam outputs and controlling the sequence of a laser beam output to be adjusted. SOLUTION: A microprocessor sets a variable M of a laser spot LD(M) to '2' and selects a laser output LD(2) (S231). After the end of laser beam output adjustment of the LD (2), the variable M is set to '4' through the steps S322, S323 and the laser beam output LD (4) is adjusted. When this adjustment of the laser beam LD (4) is finished, the variable M is set, to '1' from the M=4 through the steps S322-S324. Similarly, after the end of the adjustment of LD (1), through the steps S322, S323, the M is set to '3' and the microprocessor adjusts the laser beam output LD (3). The sequence of the laser beam output adjustment is conducted in the order of LD(2) → LD (4) → LD (1) → LD (3) so that they are not adjacent to each other in this way, then the laser beam outputs are adjusted without being affected by thermal interference.

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 printer, a copying machine or a facsimile, which scans a plurality of laser beams to form an image and a control method thereof.

[0002]

2. Description of the Related Art The structure and control procedure of a general image forming apparatus will be described below with reference to the drawings.

FIG. 9 is a block diagram showing the structure of an image forming apparatus, FIG. 10 is a flowchart showing an image forming sequence, and FIG. 11 is a flowchart showing a laser light output adjusting process.

As shown in FIG. 9, a signal line for a print signal for controlling the start or continuation of printing of the image forming apparatus is connected to the microprocessor 1 from the image controller 2. Here, when the print signal is enabled (YES in step S1), the microprocessor 1 recognizes the start or the continuation of the printing, and moves the recording material to a predetermined position in the image forming apparatus by the recording material conveying unit (not shown). A paper feeding operation for carrying is performed (step S2), and the process proceeds to laser light output adjustment processing (step S3).

Here, the image forming apparatus has four laser emission points 1101-1 to 1101 arranged in a line as shown in FIG.
The light source unit 11 configured by 104 and a photodiode 1150 for detecting the laser light output is used. In addition, the laser emission points arranged in a line are arranged in order of LD (1) 1101, LD (2) 1102, L
It is referred to as D (3) 1103 and LD (4) 1104.

First, the microprocessor 1 sets a variable M for identifying a laser to "1" and selects LD (M), that is, LD (1) 1101 (step S30).
1). Then, the light amount control signal of the LD (1) 1101 is set to the initial setting value (step S302), and the buffer selector 3 enables only the buffer latch circuit 401. The light amount control signal of the LD (1) 1101 is supplied to the buffer latch circuit 401 and the D / A converter 50.
1 to the constant current circuit 1001 provided in the laser drive circuit. Then, the constant current circuit 1001 supplies a laser drive current proportional to the light amount control signal input thereto, and the switching circuit 1051 performs ON / OFF control.

Next, the microprocessor 1 outputs data for lighting only the LD (1) 1101 to the LD forced lighting selector 8, and the output of the LD forced lighting selector 8 is sent to the switching circuit 1051 via the logical sum 901. Is entered. On the other hand, the switching circuit 1051 that has received the forced lighting signal supplies the laser operating current supplied from the constant current circuit 1001 to the LD (1) 1101 to continuously light the LD (1) 1101 to the LD (1) 1101 (step S30).
3).

Here, the laser output L1 of the LD (1) 1101 is detected by the photodiode 1150, and L
A current-voltage conversion and amplification are performed by the D light amount detector 12, and A
It is input to the microprocessor 1 via the / D converter 13. As a result, the microprocessor 1 which has detected the light output of the LD (1) 1101 as the light amount detection value P is
Light output error E between light output reference value Pref and light amount detection value P
(= Pref-P) is calculated (step S304).
At this time, if the LD (1) 1101 light amount detection value P is smaller than the light output reference value Pref, the light output error E
Is a positive value (steps S305 → S306).

Then, the light amount detection value P is the light output reference value Pr.
If it does not reach up to 90% of ef, the light output error E is larger than the value of Pref / 10. Therefore, the magnitude of I1 is increased in the light amount control signal of LD (1), and LD (1) 1101
The laser light output of is increased (step S307). This sequence is repeated until the light intensity detection value P reaches 90% or more of the light output reference value Pref.

Next, when the increased light amount detection value P becomes a value in the range of 90% or more and less than 95% of the light output reference value Pref, the light output error E becomes Pref / 20 <E≤Pre.
It becomes f / 10, the magnitude of I2 is increased in the light quantity control signal of LD (1), and the light output of LD (1) is increased (step S308). This I2 takes a value smaller than the above-mentioned I1, and improves the resolution of the light quantity control signal of LD (1). In this sequence, the light amount detection value P is the light output reference value P.
Repeated until 95% or more of ref is reached.

Further, when the increased light amount detection value P becomes a value in the range of 95% or more of the light output reference value Pref and smaller than the light output reference value Pref, the light output error E becomes E ≦ Pref.
/ 20, and the magnitude of I3 is increased in the light amount control signal of LD (1) to increase the light output of LD (1) (step S309). This I3 takes a value smaller than the above-mentioned I2, and improves the resolution of the light amount control signal of the LD (1). In this sequence, the light amount detection value P is the light output reference value Pr.
It is repeated until it becomes ef or more.

Furthermore, when the detected light amount P of the increased light output of the LD (1) reaches the light output reference value Pref (E =
0), the light amount control signal value of LD (1) is latched by the buffer latch circuit 401 (step S310), and the light amount control signal of LD (1) output from the D / A converter 501 is held at a constant value. As a result, the desired laser light output was obtained, and therefore data for canceling the laser forced lighting is output to the LD forced lighting selector 8 and LD (1) is output.
1101 is turned off (step S311).

Further, due to variations in laser characteristics or deterioration, the resolution of I1 and I2 described above is insufficient, and LD (1)
When the light amount detection value P of the light output of becomes larger than the light output reference value Pref, the light output error E becomes a negative value (E <
0). At this time, the light amount control signal of LD (1) is reduced by the value of I3 to reduce the light output of LD (1) (step S
314), and the optical output error E (= Pref-P) is calculated (step S315). This sequence is the light amount detection value P
Is repeated until the light output reference value Pref becomes less than or equal to L
When the optical output error E of D (1) becomes E ≧ 0, LD
The light quantity control signal of (1) is latched by the buffer latch circuit 401 (steps S316 → S310), and the light quantity control signal of LD (1) output from the D / A converter 501 is held at a constant value. As a result, the desired laser light output was obtained, so data for canceling the laser forced lighting is output to the LD forced lighting selector 8, and LD (1) 1
101 is turned off (step S311).

As described above, after the laser light output adjustment of the LD (1) is completed, the value of the variable M (= 1) for identifying the laser is not the predetermined value 4 which is the number of laser light emission points, but all the laser light emission points. On the other hand, since the laser light output adjustment has not been completed, the variable M is incremented (M = M + 1) (steps S312 → S313) and M = 2.

Similarly, LD (2) → LD (3) → L
The laser light output adjustment is performed in the order of D (4). LD (4)
If the value of the variable M (= 4) for identifying the laser is 4, which is the number of laser emission points, after the laser light output adjustment of No. 1 is completed, the laser light output adjustment is completed for all the laser emission points. Then, the sequence shifts to the next sequence.

As a result, the microprocessor 1 determines that the image formation is ready, and outputs a vertical synchronization request signal to the image controller 2, which requests the image controller 2 to transmit a vertical synchronization signal for synchronizing the conveyance of the recording material. (Step S4), wait for a vertical synchronizing signal from the image controller 2 (step S5). After that, when the image controller 2 receives the vertical synchronization request signal, the line buffers 601 to 601
The image data is transferred to 604 and a vertical synchronizing signal is output to the microprocessor 1. On the other hand, the microprocessor 1 that has received the vertical synchronization signal performs the printing operation on the recording material described below (step S6).

Prior to the description of the printing operation, the structure of the optical system will be described with reference to FIG.

Laser emission point LD of the light source unit 11
(1) 1101, LD (2) 1102, LD (3) 11
03, LD (4) 1104 emits central rays L1, L2, L3, L4 parallel to the optical axis of the condenser lens 1701. Then, each central ray passes through the focal point f of the condenser lens 1701, passes through the cylindrical lens 1702, and then reaches the polarization plane of the rotary polygon mirror 1703. Rotating polygon mirror 17
Each of the light beams reflected by the polarization plane of No. 03 has a spherical lens 170.
4 and a toric lens 1705 form an anamorphic scanning lens system to form an image on the surface of the photosensitive drum 18, and the electrostatic latent image is transferred to a recording medium to form an image.

A reflection mirror 1706 is arranged at the tip of the scanning line and guides the above-mentioned light flux to the beam detector 14. The beam detector 14 is composed of a light receiving element, a slit plate for individually detecting a plurality of laser beams, and an amplifier for amplifying an output signal of the light receiving element. The beam detector 14 outputs an optical output detection signal of each laser beam passing through the tip of the scanning line. Output to the comparator 15. Then, the comparator 15 converts the analog signal into a pulse signal, the timing signal forming circuit 16 separates the timing of the pulse signal for each laser, and outputs the horizontal synchronizing signals BT1 to BT4 for each laser. It

The horizontal synchronizing signals BT1 to BT4 output from the timing signal forming circuit 16 are sent to the line buffers 6 respectively.
01 to 604 are input. Line buffers 601-6
To 04, the print information corresponding to each main scanning line is transferred from the image controller 2 which holds the dot matrix information for forming an image on the print medium.
Then, the image data for one scan is output in synchronization with the image clock of the image control corresponding to the timing of the horizontal synchronizing signal. Here, the line buffers 601 to 60
The image data output from the laser diode 4 is laser LD (1)-
This is a laser modulation signal that is modulated by the LD (4) and is transferred to the switching circuits 1051 to 1054 of the laser drive circuit via the respective logical sums 901 to 904. Then, lasers LD (1) to L arranged in the light source unit 11 are arranged.
D (4) is modulated and driven, and modulated beams L1 to L4 are emitted.

After that, when the image formation on the recording material is completed, if the print signal is enabled (YES in step S7), the microprocessor 1 performs the sequence control for continuously forming the image on the recording material of the next issue. Repeat. If the print signal is disabled (NO in step S7), the image forming apparatus shifts to the standby state and waits for the next print signal to be enabled (step S2).

As described above, as a means for maintaining a uniform output of a plurality of laser beams arranged in the light source unit, one is selected from a plurality of lasers at the time of non-image formation, and the laser beam output is adjusted in order. As a result, all laser light outputs are held uniformly.

[0023]

However, in the above conventional example, as shown in FIG. 14, when the second and subsequent laser light output adjustments are performed, the temperature rise due to lighting for the previous laser light output adjustment is caused. Under the influence of transient thermal interference, the uncertainties were mixed in the environmental conditions when adjusting the laser light output. Therefore, when each laser light output is determined under the influence of the transient thermal interference, the light output of each laser varies, and the following problems occur.

(1) The recorded image density between the lasers varies, and density unevenness occurs.

(2) In the gradation reproduction characteristic, the linearity characteristic cannot be obtained.

(3) Since the horizontal synchronizing signal of each laser is determined by the laser light intensity level, a peak shift occurs between the horizontal synchronizing signal and the laser spot, and the image position in the main scanning direction varies.

Further, when the light output of each laser is fixed after the influence of the transient thermal interference is eliminated, the laser light output adjustment time becomes long, and there are the following problems.

(4) High-speed laser light output adjustment cannot be performed.

(5) The print start time of the image forming apparatus is slow.

The present invention has been made to solve the above-mentioned problems, and provides a high-quality and high-speed image forming apparatus and a control method therefor, which prevent deterioration of recorded image quality due to thermal interference of adjacent lasers. The purpose is to do.

[0031]

In order to achieve the above object, the image forming apparatus of the present invention has the following constitution.

That is, in an image forming apparatus for forming an image by scanning a plurality of laser beams, a light output adjusting means for adjusting each of the plurality of laser light outputs, and an order of the laser light output for adjusting by the light output adjusting means. And a control means for controlling.

In such a configuration, when each of the plurality of laser light outputs is adjusted, it operates so as to control the order of the adjusted laser light outputs.

In order to achieve the above object, the control method of the image forming apparatus of the present invention has the following steps.

That is, in a method of controlling an image forming apparatus for scanning a plurality of laser beams to form an image, a light output adjusting step of adjusting a plurality of laser light outputs, and a laser light adjusting by the light output adjusting step. And a control step for controlling the order of output.

[0036]

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

[First Embodiment] FIG. 1 is a flow chart showing the laser light output adjustment according to the first embodiment.
Since the configuration of the apparatus and the image forming sequence have already been described, the description thereof will be omitted. Further, the same steps as those in FIG. 11 are designated by the same step numbers.

First, the laser emission point LD (1) 110 in which the microprocessor 1 is arranged in the light source unit 11
The variable M for identifying 1 to LD (4) 1104 is set to "2", and LD (M), that is, LD (2) is selected (step S321).

Next, the light amount control signal of the LD (2) 1102 is set to the initial setting value (step S302), and the buffer selector 3 enables only the buffer latch circuit 402. The light amount control signal of the LD (2) 1102 is output to the constant current circuit 1002 arranged in the laser drive circuit via the buffer latch circuit 402 and the D / A converter 502. Then, the constant current circuit 100
2 supplies a laser drive current proportional to the light amount control signal input, and the switching circuit 1052 turns it on / off.
Control is performed.

Next, the microprocessor 1 outputs data for lighting only the LD (2) 1102 to the LD forced lighting selector 8, and the output of the LD forced lighting selector 8 is sent to the switching circuit 1052 via the logical sum 902. Is entered. On the other hand, the switching circuit 1052 that has received the forced lighting signal supplies the laser operating current supplied from the constant current circuit 1002 to the LD (2) 1102 to continuously light the LD (2) 1102 (step S30).
3).

Here, the laser output L2 of the LD (2) 1102 is detected by the photodiode 1150, and L
A current-voltage conversion and amplification are performed by the D light amount detector 12, and A
It is input to the microprocessor 1 via the / D converter 13. As a result, the microprocessor 1 that has detected the light output of the LD (2) 1102 as the light amount detection value P is
Light output error E between light output reference value Pref and light amount detection value P
(= Pref-P) is calculated (step S304).
At this time, if the LD (2) 1102 light amount detection value P is smaller than the light output reference value Pref, the light output error E
Is a positive value (steps S305 → S306).

Then, the light amount detection value P is the light output reference value Pr.
If it does not reach up to 90% of ef, the light output error E is larger than the value of Pref / 10. Therefore, the magnitude of I1 is increased in the light amount control signal of LD (2), and LD (2) 1102
The laser light output of is increased (step S307). This sequence is repeated until the light intensity detection value P reaches 90% or more of the light output reference value Pref.

Next, when the increased light amount detection value P becomes a value in the range of 90% or more and less than 95% of the light output reference value Pref, the light output error E becomes Pref / 20 <E≤Pre.
It becomes f / 10, the magnitude of I2 is increased in the light amount control signal of LD (2), and the light output of LD (2) is increased (step S308). This I2 takes a value smaller than the above-mentioned I1, and improves the resolution of the light quantity control signal of the LD (2). In this sequence, the light amount detection value P is the light output reference value P.
Repeated until 95% or more of ref is reached.

Further, when the increased light amount detection value P becomes a value in the range of 95% or more of the light output reference value Pref and smaller than the light output reference value Pref, the light output error E becomes E ≦ Pref.
/ 20, and increases the magnitude of I3 in the light amount control signal of LD (2) to increase the light output of LD (2) (step S309). This I3 takes a smaller value than the above-mentioned I2, and improves the resolution of the light quantity control signal of the LD (2). In this sequence, the light amount detection value P is the light output reference value Pr.
It is repeated until it becomes ef or more.

Further, when the light amount detection value P of the increased light output of the LD (2) reaches the light output reference value Pref (E =
0), the light amount control signal value of LD (2) is latched by the buffer latch circuit 402 (step S310), and the light amount control signal of LD (2) output from the D / A converter 502 is held at a constant value. As a result, the desired laser light output was obtained, so data for canceling the laser forced lighting is output to the LD forced lighting selector 8 and LD (2)
The light of 1102 is turned off (step S311).

Further, due to variations or deterioration of laser characteristics, the resolution of I1 and I2 described above is insufficient, and LD (2)
When the light amount detection value P of the light output of becomes larger than the light output reference value Pref, the light output error E becomes a negative value (E <
0). At this time, the light amount control signal of the LD (2) is reduced by the value of I3, and the light output of the LD (2) is reduced (step S
314), and the optical output error E (= Pref-P) is calculated (step S315). This sequence is the light amount detection value P
Is repeated until the light output reference value Pref becomes less than or equal to L
When the optical output error E of D (2) becomes E ≧ 0, LD
The light quantity control signal of (1) is latched by the buffer latch circuit 402 (steps S316 → S310), and the light quantity control signal of the LD (2) output from the D / A converter 502 is held at a constant value. As a result, the desired laser light output was obtained, and therefore data for canceling the laser forced lighting is output to the LD forced lighting selector 8 and LD (2) 1
The light 102 is turned off (step S311).

As described above, after the laser light output adjustment of the LD (2) is completed, the value of the variable M (= 2) for identifying the laser is not equal to or larger than the predetermined value 3 (step S322 → S).
323), the value of 2 is added to the variable M to set M = 4. Then, the microprocessor 1 uses L which is a variable M (= 4).
The laser light output adjustment of D (4) 1104 is similarly performed, and when the laser light output adjustment is completed, the value of the variable M (= 4) for identifying the laser is 3 or more of the predetermined value (step S322 → S324), it is determined whether the value of the variable M is the predetermined value 3. Since M = 4 (M ≠ 3) now (steps S324 → S325), the variable M is set to 1.

Similarly, the microprocessor 1 uses the variable M
When the laser light output adjustment of the LD (1) 1101 which is (= 1) is performed and the laser light output adjustment is completed, the variable M (=
The value of 1) is not equal to or greater than the predetermined value of 3 (step S32).
2 → S323), and the value of 2 is added to the variable M to set M = 3. Then, the microprocessor 1 similarly adjusts the laser light output of the LD (3) 1103 which is the variable M (= 3), and when the laser light output adjustment is completed, the variable M (= 3) is equal to or larger than the predetermined value 3. (Steps S322 → S324),
Since the predetermined value is 3, it is determined that the laser light output adjustment has been completed for all the laser emission points, and the process proceeds to the next image forming sequence.

In this way, each laser LD (1) 110
1, LD (2) 1102, LD (3) 1103, LD
(4) The order of adjusting the laser light output of 1104 is LD
By performing the order of (2) → LD (4) → LD (1) → LD (3) in the non-adjacent arrangement, the light output can be adjusted without being affected by thermal interference due to the light output adjustment of the adjacent laser. It becomes possible to do.

[Second Embodiment] Next, a second embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a block diagram showing the configuration of the apparatus according to the second embodiment, FIG. 3 is a flowchart of laser light output adjustment, and FIG. 4 is a diagram showing a memory map. It should be noted that the same reference numerals are given to those already described, the description thereof will be omitted, and only the differences will be described below. The light source unit 11 of the image forming apparatus is the same as that of the conventional example and the first embodiment.

As shown in FIG. 2, the microprocessor 1
Has CPU 101, ROM 102, and RAM inside
As shown in FIG. 4, in the memory map of the ROM 102, the register address areas R_Adr1-4 are provided.
Are assigned to the register address area R_Ad
Data indicating the order in which the laser light output is adjusted is stored in r. Further, the stored data is 4-bit data, and the laser emission points LD (1) 1101 to LD1 are arranged in the least significant bit (LSB) to the most significant bit (MSB).
(4) 1104 corresponds to each and indicates that the optical output adjustment is performed on the laser emission point LD (M) of the bit corresponding to “1”.

First, the microprocessor 1 sets the address of the register address variable R_Adr to "1" (step S331). Then, the data Data stored in the register address variable R_Adr (= 1)
(R_Adr) = Data (1) is read and the value is stored in an arbitrary address of the RAM 103 (step S
332). At this time, since Data (1) is 2H, the microprocessor 1 selects LD (2) (step S333), and the laser LD (2) 1102 is the same as in the case of M = 2 described in the first embodiment. Laser light output adjustment.

After that, when the laser light output adjustment of the LD (2) is completed, the microprocessor 1 determines whether the register address variable R_Adr (= 1) is 4 (step S334). Since the register address variable is 1 here (steps S334 → S335), 1 is added to the value of the register address variable R_Adr to be 2.

Then, the microprocessor 1 reads the data Data (2) stored in the register address variable R_Adr (= 2) (step S332).
At this time, since Data (2) is 8H, the microprocessor 1 selects LD (4) (step S33).
3), the laser light output of the LD (4) 1104 is adjusted.
After that, after the laser light output adjustment of the LD (4) 1104 is completed, since the register address variable R_Adr is 2 (steps S334 → S335), 1 is added to the value of the register address variable R_Adr to be 3.

Then, the microprocessor 1 reads the data Data (3) stored in the register address variable R_Adr (= 3) (step S332).
At this time, since Data (3) is 1H, the microprocessor 1 selects LD (1) (step S33).
3), the laser light output of the LD (1) 1101 is adjusted.
After that, after the laser light output adjustment of the LD (1) 1101 is completed, since the register address variable R_Adr is 3 (steps S334 → S335), 1 is added to the value of the register address variable R_Adr to be 4.

Then, the microprocessor 1 reads the data Data (4) stored in the register address variable R_Adr (= 4) (step S332).
At this time, since Data (4) is 4H, the microprocessor 1 selects LD (3) (step S33).
3), the laser light output of the LD (3) 1103 is adjusted.
After that, after the laser light output adjustment of the LD (3) 1103 is completed, since the register address variable R_Adr is 4,
The microprocessor 1 determines that the laser light output adjustment has been completed for all the laser emission points, and proceeds to the next step for image formation.

As described above, according to the second embodiment, the first
The same effect as in the embodiment can be obtained.

[Third Embodiment] Next, a third embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 5 is a block diagram showing the configuration of the apparatus in the third embodiment, FIG. 6 is a flowchart of laser light output adjustment, FIG. 7 is a memory map, and FIG. 8 is a diagram showing the configuration of a light source unit.

The same components as those already described are designated by the same reference numerals, the description thereof will be omitted, and only the differences will be described below.

As shown in FIG. 8, laser light emission points LD (1) 1101 to L are provided in the light source unit according to the third embodiment.
D (9) 1109 are arranged in a line. Then, the photodiode 11 that detects the laser light outputs L1 ′ to L4 ′ of the lasers LD (1) 1101 to LD (4) 1104.
51 and laser LD (5) 1105 to LD (9) 110
And a photo diode 1152 for detecting laser light outputs L5 ′ to L9 ′ of the laser beam.

As shown in FIG. 5, the microprocessor 1
Has CPU 101, ROM 102, and RAM inside
As shown in FIG. 7, the register address areas R_Adr 1 to 5 are provided in the memory map of the ROM 102.
Are assigned to the register address area R_Ad
Data indicating the order in which the laser light output is adjusted is stored in r. The stored data is 9 bits, and the laser emission point L is set in the least significant bit to the most significant bit.
D (1) 1101 to LD (9) 1109 correspond to each other, and the laser emission point LD (M) of the bit corresponding to "1"
Indicates that the light output is adjusted.

First, the microprocessor 1 sets the address of the register address variable R_Adr to "1" (step S331). Then, the data Data stored in the register address variable R_Adr (= 1)
(R_Adr) = Data (1) is read and the value is stored in an arbitrary address of the RAM 103 (step S
332). At this time, since Data (1) is 21H, the microprocessor 1 has the laser emission point LD (1) 1.
101 and LD (6) 1106 are selected (step S33
3) The laser light amount control signal is set to the default (step S302), and the two lasers are forcibly turned on (step S303).

Here, the laser light output L1 ′ of the LD (1) 1101 is detected by the photodiode 1151 and LD
The light amount detector 1201 performs current-voltage conversion and amplification, and inputs the light amount detection value P1 to the microprocessor 1 via the A / D converter 1301. And L
The laser light output L6 ′ of the laser light output 1106 of D (6) 1106 is detected by the photodiode 1152, and LD
The light-quantity detector 1202 performs current-voltage conversion and amplification, and inputs the light-quantity detection value P2 to the microprocessor 1 via the A / D converter 1302. In this way, the microprocessor 1 simultaneously adjusts the optical output of the two lasers LD (1) and LD (6), as in the above-described embodiment.

When the optical output adjustment of LD (1) and LD (6) is completed, the microprocessor 1 determines whether the register address variable R_Adr is 5 (step S34).
1). Here, since the register address variable R_Adr is 1 (steps S341 → S335), 1 is added to the register address variable R_Adr to be 2.

Thereafter, as in the case of the second embodiment, the LD (3) 1103 and LD (3) 1103 are used to adjust the optical output of the laser emission point.
(8) 1108 → LD (5) 1105 → LD (2) 11
02 and LD (7) 1107 → LD (4) 1104 and LD
(9) Register address variable R
When _Adr becomes 5, the microprocessor 1
Judges that the light output adjustment of all the laser emission points has been completed, and proceeds to the next step for image formation.

As described above, according to the third embodiment, when the light output of the laser is adjusted, a plurality of laser emission points which are not adjacent to each other are simultaneously performed, so that the intervals of the laser emission points which are simultaneously turned on are sufficiently large. The influence of thermal interference can be avoided, and the light output adjustment time of each laser can be shortened.

The present invention may be applied to a system composed of a plurality of devices "host computer, interface, printer, etc." or to a device composed of a single device "copier". . Further, it goes without saying that the present invention can be applied to the case where it is implemented by supplying a program to a system or an apparatus. In this case, the storage medium storing the program according to the present invention constitutes the present invention. Then, by reading the program into the system or device from the storage medium, the system or device operates in a predetermined manner.

[0070]

As described above, according to the present invention,
It is possible to eliminate the influence of thermal interference when adjusting the optical output of the laser, there is no variation in the optical output of each laser, and it is possible to obtain high-quality images as described below. Has the effect of improving the quality and reliability of.

(1) Improvement of accuracy of laser light output adjustment.

(2) Prevention of uneven density.

(3) It is possible to obtain a gradation reproduction characteristic having high linearity and perform high-quality intermediate gradation expression.

(4) The peak shift of the horizontal sync signal and the laser spot can be prevented.

Further, even when the number of laser emission points is increased, the light output of a plurality of lasers can be adjusted at the same time.
The time for adjusting the laser light output can be shortened, and a high-speed image forming apparatus can be provided.

[0076]

[Brief description of drawings]

FIG. 1 is a flowchart showing laser light output adjustment according to the first embodiment.

FIG. 2 is a block diagram showing a configuration of an image forming apparatus according to a second embodiment.

FIG. 3 is a flowchart showing laser light output adjustment according to the second embodiment.

FIG. 4 is a diagram showing a memory configuration according to a second embodiment.

FIG. 5 is a block diagram illustrating a configuration of an image forming apparatus according to a third exemplary embodiment.

FIG. 6 is a flowchart showing laser light output adjustment according to the third embodiment.

FIG. 7 is a diagram showing a memory configuration according to a third embodiment.

FIG. 8 is an external view of a light source unit according to a third embodiment.

FIG. 9 is a block diagram showing a configuration of a general image forming apparatus.

FIG. 10 is a flowchart showing a general image forming sequence.

FIG. 11 is a flowchart showing general laser light output adjustment.

FIG. 12 is an external view of a light source unit according to the first and second embodiments.

FIG. 13 is a diagram showing a configuration of a general optical system.

FIG. 14 is a diagram showing the relationship between the operating current of a laser and the laser light output.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Microprocessor 2 Image controller 3 Buffer selector 4 Buffer latch circuit 5 D / A converter 6 Line buffer 8 LD forced lighting selector 9 Logical sum 10 LD drive circuit 11 Light source unit 12 LD light intensity detector 13 A / D converter 14 Beam detector 15 comparator 16 timing signal forming circuit 17 scanning optical system

Claims (12)

[Claims] 1. In an image forming apparatus that scans a plurality of laser beams to form an image, a light output adjusting unit that adjusts each of a plurality of laser light outputs, and an order of the laser light output that is adjusted by the light output adjusting unit. An image forming apparatus comprising: a control unit that controls the image forming apparatus. 2. The image forming apparatus according to claim 1, wherein the control unit controls the order so that the laser light outputs to be adjusted are not adjacent to each other. 3. The image forming apparatus according to claim 1, wherein the control unit controls in the order stored in the storage unit. 4. The image forming apparatus according to claim 1, wherein the light output adjusting unit adjusts two of the plurality of laser light outputs at the same time. 5. The image forming apparatus according to claim 4, wherein the control unit controls the order so that the two laser light outputs to be adjusted are not adjacent to each other. 6. The image forming apparatus according to claim 5, wherein the control unit controls in the order stored in the storage unit. 7. A method of controlling an image forming apparatus, wherein a plurality of laser beams are scanned to form an image, a light output adjusting step of adjusting a plurality of laser light outputs, and a laser light adjusting by the light output adjusting step. And a control step of controlling the order of output. 8. The method of controlling an image forming apparatus according to claim 7, wherein the control step controls the order so that the laser light outputs to be adjusted are not adjacent to each other. 9. The method of controlling an image forming apparatus according to claim 7, wherein the control step controls in the order stored in the storage unit. 10. The method for controlling an image forming apparatus according to claim 7, wherein in the light output adjusting step, two of the plurality of laser light outputs are adjusted at the same time. 11. The method of controlling an image forming apparatus according to claim 10, wherein the control step controls the order so that two laser light outputs to be adjusted are not adjacent to each other. 12. The control method of the image forming apparatus according to claim 11, wherein the control step controls in the order stored in the storage unit.