JPH01109371A - Recorder - Google Patents

Abstract

PURPOSE:To obtain a recorder which is convenient for use and can be easily adjusted with a high precision by successively displaying the surface potential of a photosensitive body on a display part to control the quantity of light of a laser and automatizing laser power adjustment and sensitivity correction of the photosensitive drum. CONSTITUTION:When a laser power control mode is set, the rotation of a photosensitive body 1 is started by the command of a CPU 22 and a destaticizing lamp 5 and a primary charger 2 are simultaneously energized in accordance with this rotation. Thereafter, a transfer charger 6 and a separating electrifier 7 are energized, and a surface potential VD (dark part potential) of the photosensitive body 1 is controlled. That is, the output of a potential sensor 9 is read into the CPU 22 through a potential measuring circuit 13 and is fed back to a high voltage power source 17 so that the potential VD is within a specification limit. Next, laser power adjustment is executed, and a light part potential VL on the photosensitive body 1 exposed by a laser oscillator 10 is displayed on a potential display part 23, and this potential VL is controlled by a laser light quantity adjusting means 16 so that it coincides with a prescribed specification limit.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a recording device using an electrophotographic method, and particularly to a recording device having an adjustment mechanism for adjusting the output of a laser oscillator.

[Prior Art] In an electrophotographic recording device that uses a laser as a light source, a so-called laser beam printer, the amount of laser light is measured using a light-receiving element that has sensitivity near the emission wavelength of the commonly used laser. The laser power is adjusted accordingly. This is done using a so-called power checker, so when adjusting the laser power, the service person has to carry this power checker with him to the adjustment location.

In addition, there are generally variations in sensitivity among photoreceptors depending on manufacturing lots, and it would be inconvenient to adjust the sensitivity using a constant power. Furthermore, the spectral sensitivity of the photoreceptor is generally not flat, and especially when a semiconductor laser is used, its emission wavelength is in the near-infrared region, so it is difficult to use the region where the spectral sensitivity of the photoreceptor is maximum. However, it is often used in a sensitivity range where there is a sudden change in sensitivity.Therefore, there is a disadvantage that the sensitivity of the photoreceptor varies greatly in response to a slight change in the laser wavelength. Furthermore, since semiconductor lasers generally have a wavelength variation of about 10 to 30 nm, if the laser element is different in significant cases, the sensitivity may change by more than twice even with the same photoreceptor. .

Therefore, when a semiconductor laser is used as a light source for electrophotography, adjusting the amount of light (laser power) is a very important and essential adjustment item. However, the drive current for semiconductor lasers is minute, and the threshold current that indicates laser oscillation can vary by more than double between elements, and the slope of the current output characteristics also varies widely, so it is necessary to manually monitor the light intensity while monitoring the current output characteristics. If you do not adjust the output at this time, you will not be able to make sufficient adjustments, and you will also destroy the laser itself. This is a point where the situation is very different from the electrophotographic method, which uses a light source such as a numerical lamp.
This is the reason why manual adjustment has to be carried out.

[Problems to be solved by the invention] During maintenance work, replacement of the photoconductor due to deterioration of the photoconductor,
When readjusting the laser power due to an abnormality in the reproduced image, laser element replacement, contamination of the optical system, etc., the use of an expensive power checker has traditionally been a prerequisite.
Moreover, it goes without saying that there are photoreceptor sensitivity test sheets, laser wavelength test sheets, and sheets that show the sensitivity of the photoreceptor to the laser wavelength.
Sometimes readjustments, including the optical system, had to be made, burdening service personnel with complicated and time-consuming work.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and aims to provide a recording device that is easy to use and can be easily adjusted with high precision by automating laser power adjustment and photosensitive drum sensitivity correction. purpose.

[Means for Solving the Problems] In order to achieve the higher purpose, the recording device of the present invention has the following configuration. That is, a photoreceptor on whose surface an electrostatic latent image is formed, a charging means for uniformly charging the surface of the photoreceptor, and a laser generating means for forming a latent image pattern on the photoreceptor according to a recording signal. and adjusting means for adjusting the output of the laser generating means,
The apparatus includes a potential detecting means for detecting the surface potential of the photoreceptor exposed by the laser generating means, and a display means for displaying a display according to the output of the potential detecting means.

[Operation] With the above configuration, the surface of the photoreceptor on which an electrostatic latent image is formed is uniformly charged, and a latent image pattern corresponding to a recording signal is formed on the photoreceptor by the laser generating means. The output of the laser generating means is adjusted by the adjusting means, the potential detecting means detects the surface potential of the photoreceptor exposed by the laser generating means, and the display means displays a display according to the output of the potential detecting means. Operate.

[Embodiments] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a diagram showing the main configuration of a laser beam printer according to an embodiment.

In FIG. 1, reference numeral 1 denotes a photoreceptor that rotates in the direction of the arrow, and after being uniformly charged by a negative charger 2, is subjected to image exposure by laser light. The laser beam is irradiated from a semiconductor laser oscillator 1° using a direct modulation driving method. After the laser beam shape is appropriately adjusted by an optical system (not shown), the laser beam is irradiated by a scanner mirror 11 approximately perpendicular to the rotational direction of the photoreceptor 1. The photoreceptor 1 is scanned uniformly through the F-θ lens 12. The electrostatic latent image pattern thus formed on the photoreceptor 1 is visualized by the developer in the developing device 3 and transferred onto the transfer material 8 by the transfer charger 6. After the image 8 is separated from the photoreceptor 1 by a separation charger, its image is fixed by a fixing means (not shown). On the other hand, a portion of the untransferred developer remaining on the photoconductor 1 is cleaned by a cleaner 4, and finally, the static electricity on the photoconductor 1 is uniformly removed by a static elimination lamp 5, thereby completing one cycle. The figure is a flowchart of a control program for performing laser power adjustment processing in this embodiment, and these two programs are stored in the ROM 20.

FIG. 3 is a timing chart of the main parts at that time.

A more detailed explanation will be given below with reference to these drawings.

To perform laser power adjustment, follow step 5 in Figure 2.
When the laser power adjustment mode shown in 100 is turned on,
The microcomputer (CPU) 22 shown in FIG. 1 starts the sequence shown in FIG. 3 at timing T30. When the CPU 22 outputs a pre-rotation command to the photoreceptor 1 in step 5101, the photoreceptor 1 starts rotating.
Accordingly, the static elimination lamp 5 and the negative charger 2 are energized at the same time. After that, at an appropriate timing (timing T
At step 31), the transfer charger 6 and the separation charger F are energized. That is, during this period, only exposure and development are omitted in the electrophotographic process.

Next, in step 5102, VD control is performed. Here, a surface potential V of the photoreceptor 1 (generally called a dark potential because no laser light exposure is performed in this case) is detected by a potential sensor 9. This is because after the output of the potential sensor 9 is corrected and amplified by the potential measurement circuit 13,
It is converted into a digital signal by the A/D converter 14, and I10
It is read into the CPU 22 via the port 19.

The dark potential v0 read into the CPU 22 is stored in advance in the ROM.
For example, if the detected VD is lower than the standard value, The CPU 22 increases the output of the high voltage power supply 17! 10 issues a command via boat 19, and this command is sent to D/
It is converted into an analog signal by the A converter 18, and controls the high voltage output of the high voltage power supply 1f. In this way, the high voltage applied to the negative charger 2 increases, and as a result, the dark potential VD on the photoreceptor 1 increases.

By repeating such a series of detection → comparison → feedback control (step 3102.103), the value of the dark potential VD of the photoreceptor 1 is adjusted to a predetermined range, and the value of the primary charger 2 used in the subsequent process is adjusted. Driving voltage is determined (third
Figure timing T32).

When the voltage applied to the negative charger 2 is determined by the VD sub-control described above, the next step is to adjust the laser power in steps 5104 to 106 (this adjusts the surface electrolysis of the photoreceptor in the exposed area). ) is executed. This is a detection method that is almost the same as the VD sub-control described above, but the difference is that the laser oscillator 10 is always energized, and the detected value of the potential sensor 9 is sent to the potential display section 23 via the potential measuring circuit 13. It is located at the point shown in .

That is, since the laser oscillator 10 is constantly energized by the CPU 22 via the laser driver 15, the surface of the photoreceptor 1 is uniformly exposed, so that the surface potential of the photoreceptor 1 detected by the potential sensor 9 is reduced. becomes the bright area potential vL.

Since the bright area potential vL has a correlation with the exposure intensity, that is, the laser power intensity (as the exposure intensity increases, the bright area potential decreases accordingly), the service person can check the bright area displayed on the potential display section 23. While checking the value of the potential vL, adjust the laser light amount adjusting means 16 so that . This is shown at timing T33 in FIG.

On the other hand, the CPU 22 converts the bright area potential vL to the A/D converter 1.
4. It is input and monitored through the I10 port 19, and when the CPU 22 compares and determines that the bright area potential vL is within a predetermined standard value stored in advance in the ROM 20, the process proceeds to step 5IO7. Then, the laser power adjustment mode is stopped and the energization of the semiconductor laser 10 is stopped.

Next, in step 5108, the photoreceptor 1 is rotated backward (timing T34).

This step is carried out to return the electrophotographic process to its initial state after the series of adjustments have been completed. First, the charger 2 and the laser oscillator 10 are stopped, and then the transfer separation charger 2 and the laser oscillator 10 are stopped. , the rotation of the photoreceptor, the static elimination lamp 5, etc. are stopped in preparation for the original purpose of image formation using image signals.

It should be noted that even if the service engineer performs this in an appropriate manner after confirming that the adjustment of the bright area potential v has been completed as a means of transitioning from the laser power adjustment stage to backward rotation, the present invention will not work. This does not deviate from the main idea in any way.

In addition, the RAM 21 stores the flowchart shown in FIG.
The ROM 21 is used as a primary storage memory for execution by the U 22, and a program therefor is stored in the ROM 21.

Further, the recording method to which the present invention is applied may be an image scan method in which the portion to be developed is scanned with a laser, or a background scan method in which the background portion that is not to be developed is scanned with a laser. In particular, in the former case, at least when adjusting the laser power in FIG. 3 (timing T33), the developing bias applied to the developing device 3 is turned off, or the operation of the developing device 3 itself is stopped to prevent the developer from being taken out. It is desirable to do so.

In the latter case, it is desirable to perform similar processing at least during the VD control in FIG.

In the above embodiment, the VD potential control, sequence control, etc. in the flowchart shown in FIG. 2 are performed by the CPU 22 shown in FIG. 1.

Therefore, the target value during VD control etc. is stored in ROM2 in FIG.
However, when the bright decay characteristics and dark decay characteristics vary depending on the manufacturing lot, such as with a-S and photoconductors, it is necessary to change the target values of VD and vL. . In such a case, it is sufficient to be able to set several types of switching signals from the outside via the I10 port 19.

Also ■. While sequentially displaying the VD potential on the potential display section 23 without any control, the high voltage power supply 17 is manually adjusted, and -
The amount of charge of the charger 2 may be adjusted. Further, the VD voltage is not adjusted at all while the amount of charge of the negative charger 2 is fixed, and the potential contrast 'v' is determined based on the display on the potential display section 23.
It is also an effective method to adjust the amount of laser light so that c-vD-vL becomes an appropriate value.

In the embodiment described above, since the amount of laser light is adjusted via the photoreceptor potential, there is a risk that the output may be erroneously increased too much and the laser may be damaged. FIG. 4 shows a protection circuit for preventing the laser output from exceeding an allowable value and being destroyed, and the laser light amount adjusting means 16 includes an optimum light amount adjustment volume 24 and a limiter volume 25. There is. Then, the laser driver 15 in FIG. 1 is controlled by the laser output control voltage vcflt.

In the case of this embodiment, it is assumed that increasing the vant value increases the laser output. Therefore, if this value becomes abnormally high, the laser oscillator 10 will be destroyed. Therefore, by using the limiter volume 25, a maximum value can be set in advance so that even if the light amount adjustment volume 24 is maximized, vant does not exceed the allowable amount.

Incidentally, since the upper limit of the Vant value may show different values depending on the semiconductor laser element, the Vant limiter setting means is attached to the laser oscillator 10 side, as shown at 26 in FIG. It is more preferable if the light amount adjustment means 16 is placed at a location where it can be easily operated during service.

In addition, in the above explanation, the laser light intensity adjustment mode is set,
Although the explanation has focused mainly on adjustment by service personnel, the present invention may also be used as a means for adjusting image quality such as density and line width during normal use by general users. The display in FIG. 23 may be converted into numerical values and symbols corresponding to the vL potential instead of the vL potential, so that the amount of change in the image can be expressed intuitively and easily for the operator.

As explained above, according to this embodiment, a display section that can sequentially display the surface potential of a photoreceptor is provided in a laser beam printer using an electrophotographic device, and the amount of laser light is adjusted based on this display value. By doing this, there is no need to use a special light intensity measurement jig when adjusting the light intensity, and conventional problems such as sensitivity variations between photoreceptors, wavelength variations of the laser itself, and even variations in the transmission efficiency of the optical system can be resolved. There is no need to consider this at all, and the laser light intensity can be adjusted to an appropriate value very easily.

[Effects of the Invention] As described above, according to the present invention, the laser power can be easily adjusted without being affected by variations in the sensitivity of the photoreceptor or variations in the wavelength of the laser, so that stable reproduced images can be obtained. effective.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the main configuration of the laser beam printer of this embodiment, Fig. 2 is a flowchart showing the laser power adjustment process of this embodiment, Fig. 3 is a timing chart of the main parts when adjusting the laser power, FIG. 4 is a circuit diagram of a laser beam amount adjusting means having a limit function, and FIG. 5 is a block diagram showing a limiter setting means for correcting variations in laser elements. In the figure, 1...photoreceptor, 2...-charger, 3...
Developing device, 4... Cleaner, 5... Static elimination lamp, 6
... Transfer charger, F... Separation charger, 8... Transfer material, 9... Potential sensor, 10... Laser oscillator, 1
1'-...Scanner mirror, 12...F-θ lens,
13--Potential measurement circuit, 14-A/D converter, 1
5--Laser driver, tS--Light amount adjustment means,
17-...High voltage power supply, 18...D/A converter, 1
9...I10 boat, 20...-ROM, 21...R
AM, 22...Micro combinator, 23...Potential display section, 24...Light amount adjustment volume, 25...
Limiter volume 26 . . . limiter setting means.

Claims (1)

[Claims] (1) A photoconductor on which an electrostatic latent image is formed, a charging means for uniformly charging the surface of the photoconductor, and a laser generator for forming a latent image pattern on the photoconductor according to a recording signal. means, adjusting means for adjusting the output of the laser generating means, potential detecting means for detecting the surface potential of the photoreceptor exposed by the laser generating means, and a display according to the output of the potential detecting means. A recording device comprising display means for performing.