JPH08230233A - Image recording apparatus - Google Patents

Abstract

PURPOSE: To provide an image recording apparatus sufficiently adjusting the quantity of beam of a laser beam source without newly adding a complicated circuit and decreasing a printing speed or resolving power to record an image of good image quality. CONSTITUTION: A quantity-of-beam control unit 1 adjusts the quantity of output beam of a laser diode 3 and a scanner motor control part 13 performs the control raising or lowering the number of rotations of a scanner motor 14. A synchronizing interval abnormality detector 16 detects the synchronizing interval abnormality of the scanner motor 14 and a CPU 12 stops the detection operation of the synchronizing interval abnormality detector 16 temporarily. A page detection sensor 17 detects the timing performing the adjustment of the quantity of beam. By this constitution, the time performing the adjustment of the quantity of beam can be ensured by lowering the number of rotations of the scanner motor 14 at the time of the adjustment of the quantity of beam and decreasing the beam scanning speed at the time of the scanning of a quantity-of-beam adjusting region. Therefore, the desired adjustment of the quantity of beam can be performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording apparatus, and more particularly to an image recording apparatus capable of recording an image of good quality by controlling the light amount of laser light without requiring a complicated circuit. .

[0002]

2. Description of the Related Art In recent years, an image recording apparatus using a semiconductor laser has been made ozoneless due to environmental problems and the like, and transfer from a corotron is being changed to transfer by a bias transfer roll (hereinafter abbreviated as BTR).
For the image recording apparatus in which the transfer by the BTR is performed, for example, a configuration as shown in FIG. 4 has been proposed. In the figure, after the photoconductor 31 is charged by the charge roll 36, the photoconductor 31 is converted into a latent image by the irradiated laser beam 32, and the latent image is developed by the developing machine 33. Next, the image developed by the BTR 34 is transferred to the photoreceptor 31.
Is transferred to the paper 35. Then, the image is fixed on the paper 35 by a fixing device (not shown). In a conventional image recording apparatus, the light output intensity of laser light changes with temperature, aging, and the like. For this reason, there is a problem in that the density of the image recorded by the image recording apparatus changes and the image quality deteriorates.

Therefore, in order to stabilize the light output intensity of the laser light regardless of the temperature change and the secular change, the laser light 32 is regulated by the light quantity control device before the image recording apparatus starts printing an image. Control is performed so that the light amount of the laser beam is adjusted in the light amount adjustment region shown in FIG. 5A, that is, in the period between the paper 35a and the next paper 35b and in the scanning region of the photoconductor. I have to. At the time of adjusting the light amount, the developing device 33 develops the locus of the laser beam 32 on the photoconductor 31 irradiated with the laser beam 32, and the toner adheres to the locus. The photoconductor 3
1 rotates and comes into direct contact with the BTR 34,
There is a problem that the toner attached to No. 1 adheres to the BTR 34, and the back surface of the next paper 35b becomes dirty. Especially when the image recording device is in the double-sided print mode,
Since an image is printed on the back surface of the paper, if the back surface of the paper becomes dirty, there is a problem that a beautiful image cannot be printed on the back surface of the paper. In order to solve the above problems, the technique disclosed in Japanese Patent Laid-Open No. 198074/1993 has been proposed. In this image recording apparatus, as shown in FIG. 6B, the light amount adjustment of the laser light is performed in the light amount adjustment area outside the image signal scanning area of the photoconductor 31.

[0004]

In the image recording apparatus of the above-mentioned publication, the light quantity adjustment area of the laser light (see b in FIG. 6) is considerably smaller than the light quantity adjustment area shown in a of FIG. I understand. The time for sufficiently adjusting the light amount of the laser light needs to be a predetermined time or more, and the time required for the laser light to scan the light amount adjustment region shown in FIG. 6B is insufficient for the predetermined time. For this reason,
An image recording device having a low scanning speed of laser light, for example, a low resolution image recording device can perform sufficient light amount adjustment, but an image recording device having a high scanning speed, for example, a high resolution image recording device can perform sufficient light amount adjustment. There is a problem that the amount of light cannot be adjusted. The object of the present invention is to eliminate the above-mentioned problems of the prior art, to sufficiently adjust the light amount of the laser light source without newly adding a complicated circuit, without lowering the printing speed and resolution, and to obtain a good image quality. It is to provide an image recording apparatus capable of recording the image.

[0005]

In order to achieve the above object, the invention of claim 1 includes a light quantity adjusting means for adjusting an output light quantity of the laser light source, and a timing detecting means for detecting a timing for performing the light quantity adjustment. A scanner motor control means for controlling the rotation speed of the scanner motor to be reduced at the time of adjusting the light quantity, and a rotation speed of the scanner motor at other times to be specified, a synchronization interval abnormality detecting means for detecting a synchronization interval abnormality of the scanner motor, and the light intensity adjustment At the same time, it is characterized in that it further comprises means for temporarily stopping the detection operation of the synchronization interval abnormality detecting means. The invention of claim 2 is characterized in that a means for performing double-sided printing is provided.

[0006]

According to the first aspect of the present invention, when the output light amount of the laser light source is adjusted, the scanner motor control means lowers the number of rotations of the scanner motor to secure the light amount adjustment time longer than usual. Will be possible. Therefore, even in an image recording apparatus having a high scanning speed, for example, a high-resolution image recording apparatus, it becomes possible to sufficiently adjust the light amount of the laser light source. According to the second aspect of the present invention, the output light amount of the laser light source is adjusted when reversing the paper only when double-sided printing is performed, so that it is possible to prevent a decrease in printing speed during continuous high-speed printing.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing the functional arrangement of the image recording apparatus of the present invention. In the figure, 1 is a light amount control device for controlling the light amount of laser light, and 2 is a microcomputer for controlling the image recording device. Reference numeral 3 is a laser diode (hereinafter abbreviated as LD) for irradiating laser light, and 4 is a photo diode (hereinafter PD) for receiving the laser light from the LD 3 and outputting a current according to the light amount of the laser light. Abbreviated) 5
Is an amplifier that converts the current signal from the PD 4 into a voltage signal and amplifies and outputs the voltage. 6 is an analog / converting analog signal voltage to digital signal voltage
It is a digital converter (A / D). Reference numeral 7 is a reference value memory in which reference values are stored.
This is the value of the voltage that serves as a reference for obtaining a predetermined amount of laser light emitted from the laser.

Reference numeral 8 is a comparator (COMP) for comparing the digitalized voltage value (hereinafter, referred to as a digital voltage value) from the analog / digital converter 6 with a reference value. Reference numeral 9 indicates a countdown if the comparator 8 compares the digital voltage value with a reference value, and if the digital voltage value is larger than the reference value, the counter 9 counts down, while if the digital voltage value is smaller than the reference value. Is an up / down counter (U / D) that counts up, and the up / down counter 9 holds the count value for a predetermined period. 10
Is a digital / analog converter (D) for converting the digital signal from the up / down counter 9 into an analog signal.
/ A) and 11 are laser diode drive units (hereinafter referred to as LD drive units) which drive the LD 3 in accordance with the drive signal or image information from the digital / analog converter 10.

Reference numeral 12 is a CPU for outputting a control timing signal to the light quantity control device 1 at a predetermined timing, and outputting image information from an input terminal (not shown) to the LD drive section 11, and 13 is a scanner motor. A scanner motor control unit for controlling 14; a sync detection sensor for detecting a sync signal; a reference numeral 16 for monitoring whether or not the sync signal is detected by the sync detection sensor 15 at a predetermined timing; If there is an abnormality, a synchronization interval abnormality detector that detects the abnormality, and 17 is a page-to-page detection sensor that detects between pages. 18 detects the rotation speed of the scanner motor 14, and the detection result is C
The rotation speed detector 18 outputs to the PU 12, and the rotation speed detector 18 is composed of, for example, a Hall element. In the present embodiment, the CPU 12 has the symbols 6, 9, 10,
It controls each functional unit shown in 12, 13, and 16.

Next, the light amount adjusting operation of the LD 3 by the light amount control device 1 will be described. First, the PD4 is L
The laser beam emitted from D3 is received, and a current proportional to the laser beam is output to the amplifier 5. The amplifier 5 converts the current signal into a voltage signal, amplifies it, and outputs it to the analog / digital converter 6. The analog / digital converter 6 converts an analog voltage into a digital voltage. This conversion requires that an analog signal converted into a digital signal be continuously input to the analog / digital converter 6 for a predetermined time or longer. The comparator 8 compares the digital voltage value with a reference value. As a result, if the digital voltage value is larger than the reference value, the up / down counter 9 counts down, while the digital voltage value If it is smaller than the reference value, the up / down counter 9 is counted up. Up /
According to an instruction from the CPU 12, the down counter 9 counts n units (n> 1), for example, 2 units or 3 units in the case of coarse adjustment, and counts 1 unit, for example, in the case of fine adjustment.

The up / down counter 9 holds a counter value, and a D / A converter 10 converts a drive signal corresponding to the counter value into an analog drive signal.
It outputs to the LD drive unit 11. The LD drive unit 11 is
The LD drive current corresponding to the analog drive signal is output to the LD3 to drive the LD3. The LD 3 emits a laser beam of a light amount according to the LD drive current. The above light amount control operation is repeated until the digital voltage value becomes equal to the reference value. FIG. 2 is a diagram showing the relationship between the scanning speed of laser light and the time T for adjusting the light quantity of a series of laser light. SOS is a detection signal indicating the scanning start position of each scanning line, and the scanning start position is after a lapse of a specified time from the fall of the detection signal. A section S1 shows a state when the scanner motor 14 is rotating at a normal rotation speed v, and a section S2 shows a state when the scanner motor 14 is rotating at a rotation speed v ′ slower than usual. ing. LD indicates the time during which the laser light is scanning the light amount adjustment area b shown in FIG. 6, that is, the time during which the PD 4 receives the laser light. The time for scanning the light amount adjustment region b is time T1 in the section S1, and time T2 (T1 <T2) in the section S2.

Next, the operation of one embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a flowchart showing the operation of this embodiment. First, in step S1, in response to a print start signal from an external device such as a computer (not shown) or a keyboard or the like of the image recording apparatus itself,
The image recording apparatus is activated, and the light amount adjustment (coarse adjustment, fine adjustment) of the LD 3 in the startup operation is started. In this light amount adjustment, rough adjustment is first performed. In this rough adjustment, a drive current is passed through the LD 3 and the drive current is gradually increased so as to reach a specified current value. Then, if the drive current almost reaches the specified current value,
Fine adjustments are made. In this fine adjustment, the laser light of the LD 3 is made equal to the specified light quantity. Since the rough adjustment and the fine adjustment of the light amount adjustment are the same as the light amount adjusting operation of the LD 3 by the light amount control device 1 described above,
The description of the specific operation is omitted. In step S2, the image information of the first page is sent from the CPU 12 to the LD drive unit 11, and the image is printed. In step S3, whether the space between the printed page and the next page is detected by the page-to-page detection sensor 17, that is, the signal a from the page-to-page detection sensor 17 is detected by the CPU.
It is determined whether or not the data is input to 12. When this determination is affirmative, the process proceeds to step S5, while when it is negative, the process proceeds to step S4, and the light amount of the LD3 adjusted at the start-up of step S1 is held as it is.

In step S5, the synchronization interval abnormality detector 16 is turned off by an instruction (control signal b) from the CPU 12 so that the synchronization interval abnormality detector 16 does not output the synchronization interval abnormality detection signal c to the CPU 12. To do. In step S6, the scanner motor 14 is decelerated by the control signal d (deceleration command) from the scanner motor controller 13. In step S7, it is determined whether or not Vs = v 'holds, that is, whether the rotation speed Vs of the scanner motor 14 detected by the rotation speed detector 18 has reached the rotation speed v'that can secure the time T2. It is determined whether or not. If this judgment is affirmative, the time T shown in FIG.
2, that is, the time T2 that is longer than the time required for the operation of the analog / digital converter 6 can be obtained, and step S8 is performed.
Proceed to. On the other hand, if the determination is negative, the process returns to step S6. In step S8, the inter-page light amount adjustment is performed. This inter-page light amount adjustment is the same as the light amount adjustment operation of the LD 3 by the light amount control device 1, and therefore a description of the specific operation will be omitted.

In step S9, the scanner motor 14 is accelerated by the control signal d (acceleration command) from the scanner motor controller 13. In step S10, it is determined whether or not Vs = v holds, that is, whether or not the rotation speed Vs of the scanner motor 14 detected by the rotation speed detector 18 has recovered to the normal rotation speed v. When this determination is affirmative, the process proceeds to step S11, while when it is negative, the process returns to step S9. In addition,
The section from step S6 to step S9 is the section S2 shown in FIG. In step S11, the synchronization interval abnormality detector 16 that has been temporarily turned off is set to the CPU 1
It is turned on by an instruction from 2 (control signal b). In step S12, the light amount of the LD 3 is held as it is. In step S13, it is determined whether or not there is a next page. If this determination is affirmative, the process returns to step S2 and the image of the next page is printed. On the other hand, when the above determination is negative, the printing operation is ended.

As described above, according to the present invention, when the page-to-page detection sensor 17 detects the interval between the page where printing is completed and the next page, the rotation speed of the scanner motor is reduced and the laser light is emitted. The scanning speed is slowing down. Further, the synchronization interval abnormality detector 16 is turned off so that the synchronization interval abnormality detector 16 does not detect the synchronization abnormality when the rotation speed of the scanner motor is reduced. Therefore, the speed of scanning the light amount adjustment area shown in FIG. 6B becomes slower, and therefore the adjustment time for adjusting the light amount becomes longer, and even in an image recording apparatus having a high scanning speed, for example, a high resolution image recording apparatus. Therefore, the light quantity of the LD 3 can be sufficiently adjusted. Further, it is possible to prevent the back surface of the paper from being stained by the BTR and obtain a beautiful image. Further, in the present invention, the CP is added without adding a special functional configuration.
It can be executed only by changing the control program of the U12, the scanner motor control unit 13 and the like, and can be realized at a very low cost. Further, in this embodiment,
Between the page where printing is finished and the next page, the L
Although the light amount adjustment of D3 is performed, the present invention is not limited to this, and the light amount adjustment may be performed every time several pages are printed.

Further, in this embodiment, the light quantity of the LD 3 is adjusted between the page on which printing is finished and the next page. However, in the case of continuous high-speed printing, the rotation speed of the scanner motor 14 is increased. Loss due to deceleration may occur and the printing speed during continuous high-speed printing may decrease. In such a case, the above embodiment may be applied only in the double-sided printing mode. In the double-sided printing mode, first, the front surface of the paper is printed, and then the back surface of the paper is reversed by an unillustrated paper reversing mechanism so that the back surface of the paper is printed. This paper reversing operation usually requires several seconds. Therefore, the LD3 as described above
If the adjustment of the light amount is performed at the time of reversing the paper, it is possible to prevent the printing speed from decreasing during continuous high-speed printing.

[0017]

As is apparent from the above description, according to the first aspect of the present invention, the scanner motor control means lowers the rotation speed of the scanner motor when adjusting the output light amount of the semiconductor laser. It becomes possible to secure a longer time than usual for the light amount adjustment time. Therefore, even in an image recording device having a high scanning speed, for example, a high-resolution image recording device, the light quantity of the semiconductor laser can be sufficiently adjusted. Further, it is possible to prevent the back side of the paper from being stained by the BTR, and it is possible to obtain a beautiful image. In addition, since the program can be executed only by changing the control program of the image recording apparatus without adding a special functional configuration, it can be realized at a very low cost. According to the second aspect of the invention, the light amount of the semiconductor laser is adjusted during the time required for the sheet reversing operation. Therefore, it is possible to prevent a decrease in printing speed during continuous high-speed printing.

[Brief description of drawings]

FIG. 1 is a block diagram showing a functional configuration of an image recording apparatus of the present invention.

FIG. 2 is a diagram showing a relationship between a scanning speed of a laser beam and a time for adjusting a light amount of a series of laser beams.

FIG. 3 is a flowchart showing the operation of this embodiment.

FIG. 4 is a configuration diagram showing a specific example of an image recording apparatus for transfer by a conventional bias transfer roll.

FIG. 5 is a conceptual diagram showing a light amount adjustment area for adjusting the light amount of a conventional image recording apparatus.

FIG. 6 is a conceptual diagram showing a light amount adjustment area for adjusting the light amount of the image recording apparatus.

[Explanation of symbols]

1 ... Light quantity control device, 2 ... Microcomputer, 3 ... Laser diode, 4 ... Photodiode, 5 ... Amplifier,
6 ... Analog / digital converter, 7 ... Reference value memory, 8
... comparator, 9 ... up / down counter, 10 ... digital / analog converter, 11 ... laser diode driver,
12 ... CPU, 13 ... Scanner motor control unit, 14 ... Scanner motor, 15 ... Sync detection sensor, 16 ... Sync interval abnormality detector, 17 ... Inter-page detection sensor.

Claims (2)

[Claims] 1. An image recording apparatus for controlling the output light amount of the laser light source between printing sheets and outside the image signal scanning area on the photoconductor, the light amount adjusting means for adjusting the output light amount of the laser light source. And a timing detection means for detecting the timing for adjusting the light quantity, a scanner motor control means for lowering the rotation speed of the scanner motor at the time of adjusting the light quantity, and a regulation speed otherwise, and a synchronization interval of the scanner motor. A synchronization interval abnormality detecting unit for detecting an abnormality, and a unit for temporarily stopping the detection operation of the synchronization interval abnormality detecting unit at the time of adjusting the light amount, and adjusting the light amount when adjusting the output light amount of the laser light source. An image recording device characterized in that a time is secured longer than usual. 2. The image according to claim 1, further comprising means for performing double-sided printing, wherein the output light amount of the laser light source is adjusted when the sheet is reversed only when performing double-sided printing. Recording device.