JPH09127440A - Recorder of laser light system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make possible answering to a large-sized recording paper with a relatively low cost by arranging plural laser units in the direction of a main scan for a photosensitive body unit forming an image with laser light. SOLUTION: Two pieces of laser units 7a, 7b are arranged in the scan direction of a sensitive body drum 9 e.g. for A2 plate. The image data for printing are inputted from an external device such as a host computer, etc., through a communication cable to be developed to a printable image in a control controller 3. Then, the output timing is set under the control of the control controller 3, and synchronism with a polygon motor is adjusted, and the image data developed on an image buffer memory are transmitted to laser drive parts of the laser units 7a, 7b at the prescribed timing as a serial output, and the potential of the part answering to the image data is discharged on the sensitive body drum 9 by the laser units 7a, 7b, and a latent image is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser beam type recording device, and more particularly to a laser beam type recording device for outputting image data to a relatively large size recording medium.

[0002]

2. Description of the Related Art As a digital data output device, various systems such as a laser system, an LED system, a thermal transfer system, a pen system, an electrostatic system and an inkjet system have been proposed and put into practical use.

Conventionally, the pen system and the electrostatic system have been mainly used in the market of large-sized (for example, A2 size or larger) recording devices.

However, in recent years, output data is shifting from drawing output centering on line drawings to image data output such as graphics, and as a result, the above-mentioned pen system market has decreased. Further, due to the manufacturing cost and running cost of the recording apparatus, the electrostatic system is being taken over by the inkjet system and the LED system.

However, the ink jet method, LED
The system also has various problems.

That is, although the ink jet system is easy to colorize, the printing speed is slow (it takes several minutes to output one sheet of A4 size), and in order to increase the printing speed,
It is necessary to solve many problems related to the basic performance of the inkjet method. Further, in terms of the image quality of the inkjet method, gradation is limited.

The biggest problem with the LED system is that it is difficult to keep the light emission amount of several thousand LEDs arranged in a line within a predetermined range (the variation in light emission amount is ± 30. % Is the standard), and as a result, this variation has a large impact on the image quality. Furthermore, L
Since the ED method is a control method of forming an image by controlling the blinking of LEDs, there is a limit in gradation, and this is also a big problem.

As a means for solving the problems of the ink jet system and the LED system, there is a laser beam system, and the laser beam system recording apparatus has a mass production effect in the field of standard size (for example, size of A3 or smaller). Is being offered to the market at a relatively low cost.

Here, a schematic structure of a conventional standard size laser beam recording apparatus will be described with reference to FIG.

FIG. 6 is a diagram showing the relationship between a conventional laser unit and a photosensitive drum. In FIG. 6, the image start timing is determined based on the timing of the BD (Beam Detect) signal detected by the laser light detection circuit, the image data at the start image position P is read from the image memory,
The laser light is adjusted according to the data. If this work is executed up to the position Q, one raster image is formed. At this time,
The movement of the laser light from the point P to the point Q is executed by rotating the rotating mirror in the direction of the arrow.

[0011]

However, in order to realize a large-sized (for example, A2 size or larger size) laser beam type recording apparatus, it is difficult to obtain a compatible semiconductor laser itself, and the result is difficult. There are many difficulties in precision of optical system parts such as an image lens and a rotating mirror, and if these difficulties are solved, all of them cause an increase in manufacturing cost of the recording apparatus.

SUMMARY OF THE INVENTION An object of the present invention is to provide a relatively low-cost laser beam recording apparatus that can handle large-format recording paper.

[0013]

In order to solve the above-mentioned problems, the invention according to claim 1 is directed to a laser light source, a rotary mirror for deflecting laser light emitted from the laser light source, and a rotary mirror for deflecting the laser light. In a laser light recording device including a laser unit including a laser light detecting unit that detects the laser light, and a photoconductor unit that forms an image by the laser light emitted from the laser unit,
A plurality of the laser units are arranged in the main scanning direction with respect to the one photoconductor unit.

According to the first aspect of the present invention, a plurality of laser units are arranged for one photoconductor unit,
For example, in the case of A2 size (420 mm × 594 mm), two laser units (for example, for A4 size) are prepared, and each laser unit scans a range of 420/2 = 210 mm. By doing so, it becomes possible to use a standard size (for A4 size) laser unit which is inexpensive due to the effect of mass production.

According to a second aspect of the present invention, the plurality of laser units are provided with laser output timing control means for determining a laser output timing based on the detection timing of the laser light detection means provided in each laser unit. It is characterized by that.

According to the second aspect of the present invention, the laser light detecting means detects the laser light actually emitted and determines the output timing of the laser light in accordance with the detection timing of this laser light, so that it is accurate. Laser light is emitted at a timing.

The invention according to claim 3 is characterized in that the laser scanning direction with respect to the photoconductor unit in the plurality of laser units is the same direction.

According to the third aspect of the present invention, for example, the two laser units have the same laser scanning direction, so that the laser units having the same configuration (mechanical configuration and electrical configuration) can be used.

Further, in the invention according to claim 4, the laser light of each laser unit is developed on the image memory, and is subjected to light modulation based on a predetermined data value of each image memory area and is irradiated. It is characterized by

According to the invention described in claim 4, for example, FIG.
As shown in (A) and (B), one raster can be expanded in a straight line on the image memory, and the image can be output for one raster simply by specifying the expansion address. It can be controlled.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION A laser beam recording apparatus of the present invention will be described below with reference to illustrated embodiments.

FIG. 1 is an internal block diagram of this embodiment.
FIG. 2 is a plan view showing the positional relationship between the laser unit and the photosensitive drum.

First, referring to FIG. 2, the laser unit 7a,
The positional relationship between 7b and the photosensitive drum 9 will be described.

As shown in FIG. 2, for example, two first and second laser units 7a and 7b are arranged in parallel with the scanning direction of the photosensitive drum 9 for A2 size. Here, since the first laser unit 7a and the second laser unit 7b have the same configuration, the configuration of the first laser unit 7a will be described, and the description of the configuration of the second laser unit 7b will be omitted.

The first laser unit 7a includes a laser light source 7
1a, a lens 72a for focusing the light emitted from the laser light source 71a, a polygon mirror 73a for deflecting the laser light for scanning, a polygon motor drive driver 74a for controlling the rotation of the polygon mirror 73a, and the polygon mirror. A lens 75a for focusing the laser light reflected by 73a on the photosensitive drum 9 is provided, and a laser light detector 76a for detecting the laser light from the polygon mirror 73a is arranged in the vicinity of the photosensitive drum 9. There is. Laser light source 71a
The polygon motor drive driver 74a and the laser light detector 76a are connected to the controller 3, respectively.

In FIG. 1, image data for printing is sent from an external device 1 composed of a host computer or a document scanner to a controller 3 (see FIG. 2, which will be described later) of the laser optical recording apparatus via a communication cable 2. Is entered. The data format of the image data is predetermined raster data.

This image data is developed into a printable image by the controller 3. Then, under the control of the controller 3, at the timing of the print startable state, the sheet is fed from the cassette 4 in which the sheet is set in advance by the rotation driving of the sheet feeding roller 5, and is fed to the registration roller 6.

Further, the polygon motors (not shown) incorporated in the two laser units 7a and 7b are rotated, laser output is performed, correction of light amount and correction of rotation timing of the polygon motor are executed, and printing is started. Previous preparations are made.

Furthermore, the controller 3 controls the temperature of the fixing roller 8, the rotational drive of the photosensitive drum 9 (in the direction of the arrow), the rotational control of the cleaning roll 11, the charging roll 12, the developing roll 13, and the transfer roll 14, which are not shown. Input / output control of various sensors, control clutches, and switches is executed by the input / output ports indicated by reference characters A and B.

When the predetermined preparation is completed, under the control of the controller 3, the image data developed on the image data buffer memory 24 (see FIG. 3) is transferred to the lasers of the first and second laser units 7a and 7b. It is transmitted as a serial output to the drive unit at a predetermined timing. These laser output lights are output from the first and second laser units 7a and 7b in the direction of arrow C, reflected by the mirror 14 and incident on the photosensitive drum 9. Here, the photosensitive drum 9 is indicated by an arrow D.
Since it is driven to rotate in the direction, the surface is uniformly charged by the charging roll 12, and the uniform potential is discharged by the laser output light at the portion corresponding to the image data to form a latent image.

Subsequent processes are exactly the same as those of existing copying machines and the like.

Next, the expansion of the image data and the control of the laser unit will be described with reference to FIG.

The image data transmitted from the external device 1 is
It is received by the communication buffer 21 via the line 2. The received data is decoded by the CPU 22 (all operations of the CPU 22 are executed in accordance with the program stored in the program memory / work memory 23), and the image data expansion processing circuit 27 follows the decoding contents to display the image data shown in FIG. (Described later) and stored in the image data buffer memory 24.

By accumulating the received image data in a large-capacity memory such as a hard disk (not shown), it is of course possible to output the accumulated data without connecting the external device 1. The received data can be stored as it is, or can be stored as data after being expanded into image data, and further can be stored (file) as intermediate data. These are the relationship between the memory capacity of the apparatus and the time from the image data output request to the end of output, and these are configured to be selectable by the operator of the apparatus.

Further, control for starting printing is executed in parallel with the development of the above-mentioned image data.

First, the polygon motor drive signals a and b are output from the I / O controller 25, and the rotation of the polygon motor is started. The polygon motor drive signals a and b cause the polygon motor drive drivers 74a and 74b to control each motor to a predetermined rotation speed by a PLL (phase locked loop) control circuit built in the driver, and the respective drivers are controlled. The rotation information of is input to the I / O control unit 25 as polygon rotation signals c and d. When the speed difference between the polygon rotation signals c and d is equal to or more than a predetermined value, the polygon rotation signal d side is corrected by the correction signal.

From the time when the polygon motor speed is controlled to a predetermined rotation speed in this way, based on the laser output signals e and f from the image data output control circuit 26,
Laser light is output from the second laser units 7a and 7b. This laser light output is the first and second laser light detectors 76.
a, 76b (see FIG. 2), and are input to the image data output control circuit 26 as laser light detection signals g, h. The laser light detection signals g and h detect the position and speed of the laser light, set the output timing, and perform synchronous adjustment with the polygon motor.

In parallel with the above preparation, the I / O control unit 2
5, the control of each unit described in FIG. 1 is executed.

The paper to be printed is the cassette 4 (see FIG. 1).
The sheet is fed from the printer and stands by at the position of the registration roller 6. When the above-described preparation for image output is completed, the image data in the image data buffer memory 24 is output as a laser beam by the image data output control circuit 26 after being modulated.

Next, the image data and the timing until printing will be described with reference to FIGS.

The image data is expanded on the image data buffer memory 24 in the structure shown in FIG. Therefore, the image data at addresses X to (Y-1) in FIG. 4A are transferred to the left side of the image output shown in FIG. 4B (on the left side facing the photosensitive drum 9 in FIG. 2) to the addresses Y to Z
Image data is output to the right side (toward the photoconductor drum 9 in FIG. 2). If these addresses X to Z are expressed as one raster, the address X'to
(Y'-1) and Y'-Z 'are the next raster outputs, and by repeating this, the entire image is output.

FIG. 5 shows the first and second laser light detectors 76.
It is the figure which showed the timing which outputs the first data based on the laser beam detection signal (BD) detected by a and 76b (refer FIG. 2). That is, based on the first laser light detection signal BD-A1 of the first laser unit 7a, the laser deviation output X ~
(Y-1) is output, and the first laser light of the second laser unit 7b is output.
Laser bias output Y to Z based on laser light detection signal BD-B1
Is output. The image data of the first raster is output as described above. Similarly, based on the second laser light detection signal BD-A2 of the first laser unit 7a, the laser deviation output X
'-(Y'-1) is output, and the second laser unit 7b is output.
Based on the second laser light detection signal BD-B2, laser modulation outputs Y'-Z 'are output. As described above, the image data of the second raster is output. The image data output of the third raster is performed similarly.

[0043]

As described above, according to the invention described in each claim, a plurality of laser units are arranged for one photosensitive member unit (for example, a standard laser unit (for example, for A4 size) is used). 2 units, which are arranged in parallel in the main scanning direction of A2 size photoconductor units), and a small size laser unit (standard laser unit) combined with a large size photoconductor unit to form an electrostatic latent image. You can

Further, since the plurality of laser units are provided with the laser output timing control means for determining the laser output timing based on the detection timing of the laser light detecting means provided in each of the laser units, the large-sized photosensitive member unit can be provided. It is possible to form a continuous electrostatic latent image.

Further, since the laser scanning directions of the plurality of laser units with respect to the photoconductor units are the same, it is possible to use the laser units having the same structure in parallel.

[Brief description of the drawings]

FIG. 1 is an internal configuration diagram of an exemplary embodiment of the present invention.

FIG. 2 is a diagram showing an arrangement relationship between a photosensitive drum and a laser unit of the embodiment example.

FIG. 3 is a block diagram of a controller according to the embodiment.

FIG. 4A is a diagram showing a structure of an image memory,
(B) is a diagram showing image output.

FIG. 5 is a diagram showing a laser light detection timing and a laser light bias output timing.

FIG. 6 is a diagram showing a relationship between a conventional photosensitive drum and a laser unit.

[Explanation of symbols]

1 External Device 3 Control Controller (Laser Output Timing Control Unit) 7a, 7b Laser Unit 9 Photosensitive Drum (Photosensitive Unit) 21 Communication Buffer 24 Image Data Buffer Memory (Image Memory) 25 I / O Control Unit 26 Image Data Output Control Circuits 71a, 71b Laser light sources 73a, 73b Polygon mirrors 76a, 76b Laser light detector

Claims (4)

[Claims] 1. A laser unit comprising a laser light source, a rotating mirror for deflecting the laser light emitted from the laser light source, and a laser light detecting means for detecting the laser light deflected by the rotating mirror. A laser beam recording apparatus including a photoconductor unit that forms an image by laser light emitted from a laser unit, wherein a plurality of the laser units are arranged in the main scanning direction with respect to the one photoconductor unit. A laser light type recording device characterized by the above. 2. The laser unit includes a laser output timing control unit that determines a laser output timing based on a detection timing of a laser beam detection unit provided in each laser unit. 1. The laser light type recording apparatus according to 1. 3. The laser beam recording apparatus according to claim 1, wherein the laser scanning directions of the plurality of laser units with respect to the photoconductor unit are the same. 4. The laser light of each laser unit is expanded on an image memory, and is subjected to light modulation based on a predetermined data value of each image memory area and is irradiated. 1. The laser light type recording apparatus according to 1.