JPH0560103B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optical information recording device used in a facsimile receiving device, a word processor, an output device such as a computer, or other information recording device.

(Prior Art) FIG. 4 shows a layout diagram of the main processes around the photosensitive drum of a laser beam printer as an example of the above-mentioned optical information recording device. 101 is a photosensitive drum as a recording medium consisting of an electrophotographic photosensitive layer 102 and a substrate 103; 104 is a primary charger; 105 is a laser beam; 106 is a doctor blade 107;
A developing device consisting of a magnet roller 108 and a sleeve 109, T is toner, 110 is a pre-exposure lamp,
111 is a transfer paper guide, 112 is a transfer charger, 1
13 is a rubber blade 114 and a magnet roller 11
5. A cleaner consisting of a screw 116, a housing 117, etc.

The laser beam 105 is emitted from a laser 2 such as a semiconductor laser that is driven in accordance with a recorded signal. That is, the laser beam 105 is modulated in accordance with the recorded signal. This laser beam 105 is deflected and swept by a rotating polygon mirror 118 and scans the photosensitive drum 101. A lens 119 forms an image of the laser beam 105 on the photosensitive drum 101 in the form of a spot. Laser 2 is
It is replaceably attached to a support member 121 by screws 120.

First, the photosensitive drum 101, which has been uniformly charged by the primary charger 104, is exposed to a laser beam 105 modulated in accordance with an image signal, and an electrostatic latent image is formed on the photosensitive drum 101. continue,
The latent image on the photosensitive drum 101 is made visible through a developing process by a developing device 106. Thereafter, the developed image is transferred by a transfer charger 112 onto a transfer paper (omitted in this figure) introduced by a transfer paper guide 111. The transferred toner image is fixed on the transfer paper by a fixing device (not shown), and is discharged outside the machine to obtain a hard copy.

On the other hand, the untransferred toner remaining on the photosensitive drum 101 is removed from the surface of the photosensitive drum 101 by a rubber blade 114, adsorbed by a magnet roller 115, and further removed by a screw 116, which forms part of a housing 117. The toner is stored in a toner collection box (not shown). The photosensitive drum 101 thus neutralized is sent to the first step, the primary charging process, and is used repeatedly.

In the step of irradiating the laser beam 105, the laser beam 105 is irradiated onto a portion of the photosensitive drum 101 corresponding to the portion to which toner adheres and is visualized in the developing step, and the background other than the toner image is irradiated with the laser beam 105. An image scan method is adopted in which irradiation with the laser beam 105 is not performed. In other words, toner is attached to the bright area of the photosensitive drum 101 that is illuminated by the laser beam 105, and toner is not substantially attached to the dark area of the photosensitive drum 101 that is not exposed to the laser beam 105. A reversal development method is used. Compared to the background scanning method in which the background is irradiated with the laser beam 105 and the laser beam 105 is not irradiated only on the portion corresponding to the visible image, this method does not cause scan marks on the background image and has improved reproducibility of the visible image. This is because it is excellent.

The toner T in the developing device 106 is charged to the same polarity as the charging polarity of the temporary charger 104 due to mutual friction and contact friction with the sleeve 109, doctor blade 107, and the like. The charged toner T is placed on the sleeve 109 with a uniform thickness by the doctor blade 107. As the sleeve 109 rotates, the toner forms a latent image at the closest portion between the photosensitive drum 101 and the sleeve 109 due to the electric field between the potential of the developing bias voltage applied to the sleeve 109 and the electrostatic latent image potential. The area corresponding to the bright area potential of the latent image is developed.

(Problem to be solved by the invention) However, in the case of such conventional examples, when the laser reaches the end of its lifespan, the laser is no longer output and white spots appear on the image, or the laser beam usually has a sharp peak in the center. As the intensity distribution of the image begins to have multiple peaks and the intensity becomes weaker, the detection position of the laser beam, which determines the timing of the start of image output of the laser beam in the scanning direction, changes.
The synchronization of cueing in the scanning direction of the image cannot be achieved, resulting in malfunctions such as image fluctuations.

In order to prevent such problems, a method has been proposed in which the lifespan of lasers, LEDs, etc. is detected by integrating the number of dots corresponding to the image area (Japanese Patent Laid-Open No. 58-224363). The lifespan of lasers, etc. is determined by the total light emission time, but in this case it is assumed that the light emission time per dot is the same, so a predetermined number of dots corresponding to the total light emission time that will reach the lifespan is set in advance. The purpose is to detect the lifespan based on the number of dots.

However, the lifetime of a laser varies not only by the emission time but also by the laser output. That is, even for the same light emission time, a laser with a higher output level will deteriorate more quickly than one with a lower output level, and its life will be correspondingly shorter. Therefore, there has been a problem that the lifespan of the laser cannot be accurately determined just by measuring the emission time of the laser.

The present invention was made to solve the problems of the prior art, and its purpose is to:
Detects the lifespan of the optical information light source more accurately, prevents image defects such as memory and ghosting caused by the lifespan of the light source, and always outputs an appropriate image, as well as informing service personnel when to replace the optical information light source. The objective is to enable prompt service activities by demonstrating the

(Means for Solving the Problems) The present invention that achieves the above object is an optical information recording device that exposes a recording medium to light using an optical information light source that emits light that is modulated in accordance with a recorded signal. , a storage means for storing light emission time information of the optical information light source, and a predetermined addition amount added at a predetermined period to the light emission time information of the optical information light source stored in the storage means at a predetermined period when the optical information light source is emitting light; and an addition means for storing the optical information in the storage means, and comparing the light emission time information of the optical information light source stored in the storage means with a predetermined level set in advance, and calculating the optical information stored in the storage means. Comparing means for outputting a signal indicating that the life of the optical information light source has come to an end when the light emitting time information of the light source exceeds a predetermined level set in advance, and corresponding to the input signal to the optical information light source, The apparatus includes a correction means for increasing the predetermined amount of addition when the output of the optical information light source is large, and decreasing the predetermined amount of addition when the output is small.

(Example) The present invention will be explained below based on the illustrated example.

FIG. 1 shows the main parts of an optical information recording device according to an embodiment of the present invention, and in this figure, the same members as those in the electrophotographic device shown in FIG. 4 described above are given the same reference numerals. be. In the figure, 1 modulates the recorded signal fv, such as an image signal input from a computer (not shown) or the like, a light emission signal for light emission output adjustment, a light emission signal for writing start position alignment, into a laser input voltage; This is a modulator that turns the laser on and off in response to the recorded signal fv. A multilevel signal can be used as the recorded signal fv. That is, the light emitting time corresponding to one pixel per dot is increased for a high density portion of the image, and the light emitting time corresponding to one pixel per dot is shortened for a middle tone density portion of the image. A laser 2 is connected to the modulator 1 and serves as an optical information light source that emits light in accordance with the modulated signal, and is used in the same manner as the electrophotographic apparatus shown in FIG. A counter 3 is connected to the modulator 1 and measures the output time from the modulator 1 to the laser 2, that is, the light emission time of the laser 2. A clock pulse generator 3', such as a crystal oscillator, is connected to the counter 3, and is adapted to measure the number of clock pulses as time information received during the duration of the light emission signal of the laser 2. Furthermore, a memory 4 is connected to the counter 3 and sequentially adds and stores the output from the counter 3, and the memory 4 is connected to a comparator 5 as a comparing means. This memory 4 corresponds to the storage means of the present invention, and the counter 3 and clock pulse generation means 3'
This counter 3 constitutes the adding means of the present invention,
The clock pulse generating means 3' and the memory 4 constitute a measurement storage means 4'. The comparator 5 is connected to a controller 6 as a correction means, and compares the emission time of the laser 2 stored in the memory 4 with a predetermined level set in advance by the controller 6 corresponding to the average lifespan of the laser. When the emission time of the laser 2 stored in the memory 4 is long, a signal is input to the controller 6, and the controller 6 outputs a signal Su indicating that the laser's life has come to an end. . This signal Su causes a display means 7 such as a light emitting diode to emit light, so that it is possible to visually check whether the life has come to an end. In this embodiment, a light emission signal is used, but a sound signal such as voice may also be used. Further, the controller 6 and the memory 4 are connected, and when a reset button 8 or the like is pressed, a reset signal RST is inputted from the controller 6 to the memory 4, and the light emission time stored in the memory 4 is returned to zero.
Furthermore, the controller 6 is connected to the laser 2,
The controller 6 changes the output of the laser 2 and at the same time corrects the amount of time information added from the counter 3 to the memory 4. That is, when the laser output is large, the amount of addition is large, and when the output is small, the amount of addition is made small. Fig. 2 is a correction diagram of the amount of addition mentioned above with respect to the laser output, and when the output of laser 2 is maximum (MAX), the amount of addition is maximum,
When it is the minimum (MIN), the amount of addition should be minimized.
That is, if the normal (N) output is 1, the maximum (MAX) is 1.25, and the minimum (MIN) is 0.75. Further, in FIG. 2, the relationship between the laser output and the amount of addition does not necessarily have to be a straight line, but may be a curved relationship.

The other configurations are substantially the same as those in FIG. 4.

Next, the operation of this embodiment will be explained. First, a recorded signal fv is modulated by a modulator 1 and input to a laser 2. The laser 2 emits light (or attenuates or extinguishes light) in response to the recorded signal fv. The output of the laser 2 is controlled by a controller 6, and the bright area potential on the photosensitive drum 101 after exposure is changed to adjust the image density.

At the same time, counter 3 outputs laser 2 from modulator 1.
The output signal is measured and time information corresponding to the emission time of the laser 2 is added from 0 to the memory 4, and the amount of addition is corrected by the controller 6. Furthermore, the comparator 5 compares the contents of the memory 4 with a predetermined value, and compares the contents of the memory 4 with a predetermined value.
When the light emission time of the laser 2 stored in is longer, a signal is output to the controller 6. Upon receiving this signal, the controller 6 outputs a signal Su indicating that the life of the laser 2 has come to an end, lights up the display means 7, such as a light emitting diode, and informs the user or service personnel that it is time to replace the laser 2. Let me know. After replacing the laser 2, the service person presses the reset button 8 or the like, so that the controller 6 outputs a reset signal RST and the memory 4 is reset to zero. Also, the signal Su indicating that the life of laser 2 has come to an end is also erased.

The lifetime of the laser 2 described above has an approximately normal distribution as shown in Figure 3, so its average lifetime m
If the signal Su indicating that the life of laser 2 has come to an end is outputted at an early stage of 2σ to 3σ (σ is the standard deviation),
During this period, the failure rate due to the lifespan of laser 2 is extremely low at 4.6% to 0.3%, and reliability is high.

Alternatively, the laser 2 and the memory 4 may be fixed to the same support to form the same unit, and the memory 4 may be replaced at the same time as the laser 2. In this way, the service person only needs to replace the laser 2 and there is no need to reset the memory 4. Therefore, there is no possibility that the service person forgets to reset the memory 4 when replacing the laser 2 and a signal Su indicating that the life of the laser 2 has come to an end earlier than the life of the laser 2 is generated. Furthermore, it is possible to immediately determine whether the laser 2 is a used laser or a new laser by looking at its memory contents.

The above example shows a case where a laser is used as a light source, but an LED array in which a large number of small light emitting diodes (LEDs) are arranged in a direction intersecting the direction of movement of the recording medium, and each LED is driven to blink in response to the recording signal. It can also be applied to detecting the lifespan of the LED array of the device used. Further, the recording medium is not limited to an electrophotographic photoreceptor, but a silver salt photoreceptor can also be used, and an optical-magnetic recording medium can also be used.

Further, in the above embodiment, the length of the lighting time or the lighting-off time of the light source was measured as time information using a clock pulse, but as in JP-A-58-224363, the number of dots in the image, that is, the number of times the light source is emitted or turned off, is measured. This may be used as time information of the lighting time or the lighting time. However, there is some variation in the light emission or extinguishing time for one dot of the light source, depending on the individual light source, and if the light source is driven by a multi-level signal as described above, the image density will depend on the lighting or extinguishing time of one dot. In this case, the former is preferable because the optical information light source can be detected more accurately.

(Effect of the invention) The present invention consists of the above structure and operation,
The time information of the light emission time of the optical information light source stored in the measurement storage means is increased by the correction means when the output of the optical information light source is high, and is decreased when the output is low, so that the life of the optical information light source can be extended. Accurate detection is possible, problems caused by the lifespan of the optical information light source are prevented, and the user's work is prevented from being delayed due to the lifespan of the optical information light source. Furthermore, by notifying the service engineer of the time to replace the optical information light source, the time required for the service engineer to discover a defective optical information light source can be saved, and the replacement optical information light source can be prepared in advance. Therefore, it is possible to adopt a planned service system, and the effect is that prompt service activities are possible.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an optical information recording device according to an embodiment of the present invention, FIG. 2 is a diagram for correcting the amount of addition to the laser output, FIG. 3 is a diagram showing the distribution of laser life, and FIG. 1 is a schematic configuration diagram of a conventional optical information recording device. Explanation of symbols, 1... Modulator, 2... Laser (optical information light source), 3... Counter, 3'... Clock pulse generator, 4... Memory, 4'... Measurement storage means, 5... Comparator (comparison means), 6
...Controller (correction means).

Claims (1)

[Scope of Claims] 1. An optical information recording device that exposes a recording medium with an optical information light source that emits light modulated in accordance with a recorded signal, comprising: a storage means for storing light emission time information of the optical information light source; , an addition means for adding a predetermined addition amount to the light emission time information of the optical information light source stored in the storage means at a predetermined period during a period when the optical information light source is emitting light, and storing the added amount in the storage means; The light emission time information of the optical information light source stored in the means is compared with a preset predetermined level, and the light emission time information of the optical information light source stored in the storage means exceeds the preset predetermined level. a comparison means that outputs a signal to notify that the life of the optical information light source has reached the end of its life; 1. An optical information recording apparatus comprising: a correction means for increasing the amount of addition, and reducing the predetermined addition amount when the output is small.