JPS59194566A - Picture recorder - Google Patents

Abstract

PURPOSE:To suppress the variance of exposure to a photosensitive recording medium by finding and storing light quantity compensating information in each element and compensating the quantity of light at the time of recording on the basis of the light quantity compensating information. CONSTITUTION:The brightness value of each element is previously measured and the light quantity compensating information is found out in each element and stored in a memory 22. Any one or two of the voltage value, current value or time width of a driving signal of each element is compensated on the basis of the light quantity compensating information to compensate the exposed value of each element. Since the exposure to the photosensitive recording medium is made uniform conditions such as the variance of light emitting elements or light quantity controlling elements or the unevenness of the quantity of light can be relaxed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention uses a light emitting element such as a light emitting diode or a light amount control element such as a liquid crystal to control the exposure of a photosensitive recording medium according to an image signal, thereby producing an image. The present invention relates to an image recording device for recording.

Conventional configuration and its problems The voltage or current value of the drive signal applied to the light-emitting elements such as a large number of light-emitting diodes arranged linearly or in a staggered manner, the light amount control element such as the shunting liquid crystal, and the time width of the shunting time. One or both of them are controlled as image signals, and a photosensitive recording medium such as a photosensitive selenium drum is exposed with the light emitted from each light emitting element, and the light emitted from a light source with a constant amount of light and transmitted through each light amount control element. By doing this, the image corresponding to the image signal (
Image recording apparatuses that record (a) images (image distortion or visualization) are known.

FIG. 1 is a block diagram showing the configuration of a conventional image recording apparatus as described above.

In this figure, 11 is an input terminal into which image signals are input in series, 12 is a light emitting diode (abbreviated as LED) drive amplifier circuit, 13 is an LED array section, 14 is a scanning clock circuit, and 16 is a recording section. It is.

The LED array section 13 includes an LED array 1Sa formed by arranging three LEDs in a straight line or in a staggered manner along the straight line, and an optical lens or a group of converging optical fibers for condensing the light emitted by the LED array 13a. The optical system 13b consists of: The recording section 15 includes a photosensitive selenium drum 16a which is a photosensitive recording medium, a 7F charging section 15b, a developing section 15C1 and a transfer section 15 arranged around the photosensitive selenium drum 16a.
d, a cleaning section 158, and the like. LED
The drive amplifier circuit 12 is an LED array 13a17) LE
It has the same number of amplifiers as the number D, the input of each of these amplifiers is coupled to the input terminal 11, and the output is connected to the LED array 13a.
1, respectively coupled with the corresponding LEDs of the He recording operation will be described below.

An image signal of an image to be recorded is serially inputted from the outside to the input terminal 11 in synchronization with the scanning clock output from the scanning clock circuit 14. Each amplifier in the LED IIIK moving stage width circuit 12 operates sequentially and selectively in synchronization with the input of the image signal according to the scanning clock output from the scanning clock circuit 14, and generates a drive signal (time width) of a voltage value desired to be converted into an image signal. is constant) is applied to the corresponding LED. For example, when recording a black-and-white image, when a "black" image signal is input, the selected amplifier outputs a drive signal with a constant voltage value, causes the corresponding LED to emit light, and When the image signal is input, the selected amplifier outputs a drive signal of Q volts (does not output a drive signal), and does not cause the corresponding LED to emit light. Light emitted from each LED on the LED array 13a driven in this manner is imaged onto the photosensitive selenium drum 16a via the optical system 13b.

The photosensitive selenium drum 15a is rotated in the direction of the arrow in the figure by a driving means not shown in the figure. L
LEDi photosensitive selenium drum 15 on ED array 13a
They are arranged in the axial direction of a. Photosensitive selenium drum 16
The surface of a is uniformly charged to a specific polarity when passing through the charging section 15b, and then exposed to light from the LED array 13a, thereby recording an electrostatic positive image corresponding to the image signal 11. . The recorded portion of this electrostatic latent image is sent to the developing section 15c and developed, resulting in a developed image (toner image).
kl, plain paper (not shown in the figure) in the transfer section 15d -\l;j
le will be photographed. Is this plain paper from the transfer section 16d in the figure? ′
1. The image is sent to the fusing unit (not shown), undergoes fusing processing, and becomes a vertical copy. Photosensitive t1 selenium drum IT5a
The part that passes through the transfer part 16d is the cleaning part 15.
After the residual toner is removed by e, it is sent to the i4% section 15b.

j(]'' In this example, the LED drive amplifier circuit 1
2. To sequentially select each LED of the LED array 13a, main scanning is performed with the knee, and sub-scanning is performed with the rotation of the photosensitive selenium drum 15a.

By adopting the matrix apposition, LE
There is also a known conventional example in which the number of i+11 width amplifiers in the D drive amplifier circuit 12 is smaller than the number of LEDs in the LED array 13a.
There is. In order to cope with the continuous increase in recording speed, both signals for one scanning line are stored in the buffer memory, and then
By operating all the amplifiers in the LED drive amplifier circuit 12 at the same time and driving all the LEDs on the LED array 13a at the same time according to the corresponding image signal in the buffer memory,
A conventional example is also known in which the light emitting time allocated to each LED element is increased.

Now, the biggest technical problem with the above-mentioned image recording apparatus is that variations in the characteristics of the light emitting elements or light quantity control elements, unevenness in the light quantity of the optical system, etc. cause variations in the amount of exposure of the photosensitive recording medium. As a result, the recording density becomes non-uniform and the quality of the recorded image deteriorates.

In contrast, in the past, LEDs with uniform characteristics were used.
This is dealt with by configuring the array 13a, but the LED
There was a problem in that the manufacturing yield 9 was poor and the price of the LED array 13a increased due to the necessity of sorting the LEDs. However, even if the LED array 13a with less variation in the amount of light is obtained in this way, there is still the problem that unevenness in the recording density due to the unevenness in the amount of light in the optical system 13b, such as an array of convergent optical fibers, still remains.

OBJECT OF THE INVENTION The present invention eliminates the above-mentioned conventional problems, and even if the conditions regarding the unevenness of the light amount of the optical system due to the variation in the characteristics of the light emitting element or the light amount control element are relaxed from the conventional ones, the recording density will not change. An object of the present invention is to provide an image recording device that records high-quality images of various types.

Structure of the Invention The present invention provides means for storing light amount correction information for each light emitting element or light amount control element that controls exposure of a photosensitive recording medium, and a voltage of a drive signal for each of the light emitting elements or light amount control elements. value or current value, candy number≠bu or time width (application time)''; W j:iTh'''-J'' 8
The amount of exposure on the photosensitive recording medium for each of the light emitting elements or each of the light amount control elements can be adjusted by using a means for correcting only the corresponding light amount correction information that is used. The aim is to suppress the variation in the results and achieve the above-mentioned objective.

To supplement the explanation, when a constant '-river or' current is applied to a light-emitting element or a light amount control element, the brightness obtained on the photosensitive recording medium is L (lux), and the duration of that brightness is T (seconds) is the exposure amount K (looks -
second) is given by=LT. If the value of K is kept constant, the recording density can be made uniform, but in general, the value of L differs from element to element due to variations in the characteristics of the light emitting elements and light amount control elements, and unevenness in the amount of light in the optical system. Therefore, the present invention
Measure the value of L for each element in advance, obtain and store light amount correction information for each element to compensate for variations in the L value,
The idea is to eliminate the voltage value or current value, ←+, of the drive signal for each element, which was used as the light amount correction information during recording.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 is a block diagram of an image recording apparatus according to an embodiment of the present invention. In this figure, the symbols 11°12.13,
The parts marked 14 and 15 are respectively similar to the corresponding parts in FIG. However, the scan clock circuit 14 sends out an address signal, which will be described later, in addition to the scan clock. Further, the scanning clock and the image signal input to the input terminal 11 are sent to the LED drive 1 to width circuit 12 via the pulse width correction circuit 21. 7 22 is a memory only for explanation (abbreviated as ROM).

This ROM22 contains the LED array part 1, part 3 E])
Light amount correction information (described later) for each LED making up the array is stored in advance. By updating the value of the address signal in synchronization with the scanning clock, the k1"i~ri0 check circuit 14 specifies, in the ROM 22, the storage address of the light intensity correction information for the LED to be driven and +jυ. The light amount correction information is output from the ROiVi22.

1-Recording is a binarized pulse of constant width with a main scanning period T1 duty of about ○ (white = no pulse, °
"Black" is with pulse), and the run is the same as the clock 1iJ
I and is input to the input terminal 11.

The 1□1 SHIHARUSU wide-sleeve IF circuit 21 is a 10-bit pulse width modulator, which corrects the pulse width of the image signal inputted from the input terminal 11 so as to match the light intensity correction information inputted from the ROM 22. The corrected image signal is sent to the LED drive amplifier circuit 1.
Enter into 2. The amplifiers in the LED drive drive amplification circuit 12 operate sequentially and selectively according to the scanning clock as in the conventional case, and the width amplifier amplifies the image signal whose pulse width has been corrected by the pulse width correction circuit 21. The resulting signal is applied as a drive signal to the corresponding LED (the voltage values of the drive signals for the "white" and "black" image signals are each constant).

FIG. 3 is a diagram for explaining the operation of this image recording apparatus. Figure 3a shows that when each LED of the LED array is driven according to a "black" image signal without pulse width correction of the image signal, each LED on the photosensitive selenium drum is
The brightness Li (i is the number of the LED) obtained by D is shown as a relative value with respect to a reference value of 100. Figure 3 shows the pulse width T i of the drive signal for each LED necessary to obtain the reference exposure amount K = 10000 (relative value).
= indicates the value of /L i. Here, Ti is a relative value with the reference value being 1o○. This Tl value is 1:tOM as the light compensation +-I': +1'-thickness 416
Stored in 22. FIG. 3C is a waveform diagram of the input signal inputted manually to the output terminal 11, and FIG. 3DU is a waveform diagram of the drive signal (after pulse width correction). , an LED array is generally composed of 1,000 LEDs, but here we use 1Q LEDs to simplify the theory ψ.
It is assumed that D constitutes an LED array.

Don't explain how it works! ``Ti#1lli, 1-1 LEDK compatible j, S'' Wj times signal is manually powered, R○tvi
Corresponding light from 22) I: Correction information T1 Or, the pile is extracted and the pulse welfare [1 groaning path 21 is forced. T with
1 value is 100 (〕・(quasi-value)), so the pulse width correction is actually easy, and the image signal is inputted to the input amplifier circuit 12 with that pulse width. , as shown in Figure 3d, a drive signal (with the same pulse width as the human-powered image signal) is applied to the LED 1-1. Since the L value of this LED is 100 (reference value), K =L
1. The exposure amount of T1-10000 (reference value) is recorded in the recording section 15.
(Inner feeling)'e i'l Give to Celentrum (not shown).

When an image signal of ``black and white'' corresponding to LED 2 is input to LED 2, the corresponding light amount correction information T2 is output from the ROM 22.The value of T2 is about 83, and the image signal is about 83q.
/) is input to the LED drive amplifier circuit 12, and a drive signal having that pulse width is applied to the LED.

Since L2:120, the exposure KK on the photosensitive selenium column by LED is about 10,000.
In the case of ED, Ti is 120 and Li is 83, and the pulse width of the "black" image signal is corrected to about 120%, so
An exposure amount of 10,000 K is applied to the photosensitive selenium drum.

As mentioned above, the pulse width (time width) of the drive signal is reduced for LEDs with large L values, and vice versa.
For D, by increasing the pulse width of the drive signal, the exposure amount K of each LED can be kept almost constant to the reference value 10,000, but even if there are variations in the characteristics of each LED or unevenness in the light amount of the optical system, recording is possible. Once it is almost completely homogenized.

Incidentally, since the operation of the recording section 15 is the same as the conventional one, the explanation thereof will be omitted.

FIG. 4 is a block diagram of an image recording apparatus according to another embodiment of the present invention. Code 11.12, 13°14.16.
22 designates the same parts as the same reference numerals in FIG.
The information differs from the above embodiment as described below. 23 is a voltage correction circuit (a kind of multiplier), and input ψ11]; child 1
The image signal input from 1 (the same binary 71ii signal as in the real example) is corrected according to the light intensity correction information given from the ROM 22. 'y k L E D drivefi),
1 j! Z 12 K Manually powered. However-]
, each LED of the LED array [B, Xj corresponding light M + I
The voltage value is corrected by i (positive/information) (71), and the first driving signal (pulse width is constant) is applied from the LED driving amplifier circuit 12.

Figure 5 is a diagram for explaining the operation of this image recording device.
1. Indicates the initial brightness Li of each LED on the photosensitive selenium drum (relative value of 1 to the reference value 100) measured in the absence of 1'1 EL. Figure 6 shows the standard 91 light f.
'Ii: Indicates the voltage value ■1 of the drive signal for each LED necessary to obtain K = 10000 (relative value).

This voltage value Vi is light amount correction information for each LED, and is shown as a relative value with the reference value being 100. FIG. 5C is a waveform diagram of an image signal, and FIG. 6D is a waveform diagram of drive signals for each LED. (The voltage values are shown as relative values.) To explain the operation, when the corresponding "black" image signal is input to the LED 1-1, the corresponding light amount correction information ■1 or R is input.
Read from OM22. ■ Since it is a 1 value (41oo (reference value), the picture name is not corrected for the voltage intrusion (it is input to the LED drive amplifier circuit 12, and the drive signal of the reference voltage value joo is sent to the corresponding LED ( The pulse width is the same as the image signal) is applied.

Since the Ll value of this LED is the reference value 10Q, -10000 or -10000 of the reference exposure amount is given to the photosensitive selenium drum.

In the case of an LED with l=2, ■1 u83, the voltage value of the image signal is corrected to about 83%, and therefore the LED has a voltage value of about 83% of the reference voltage value! 4j't Motion number 44 is applied. Since L2 ” 120, j+'(
'-, t4. H is approximately 10,000.

Thus, in this embodiment, the ratio value of each LED is set to 1ψ/ζ by changing the ratio value to 1ψ/ζ. , uniformity of the exposure amount is achieved.

In addition, each of the embodiments described in -1- is based on the drive 1.1 times' width and r↓electricity 1 (- value is used as light intensity correction information, or it is possible to use a combination of both. +-, iJ function.For example, it is possible to perform coarse correction by controlling the output value, and fine correction by controlling the lus width.In addition, the above example will be explained for the case of a binary image signal. However, it is clear that the method can be similarly applied to halftone image signals.

', 'A'+; Figure 6 (This is a diagram for explaining the operation when a halftone image signal is input to the image recording device shown in Figure 2. Figure 6a and Figure 6. are respectively rth
'' is the same as in Figures a and 5. FIG. 6C is a waveform diagram of the halftone image signal, and FIG. 6D is a waveform diagram of each LED.
'ijl]'1 is a waveform diagram.

As is clear from the comparison between Figure 6C and Figure 6D, each L
The voltage value of the drive signal for ED is the ratio of the image signal IJII
L and pulse width are corrected by a pulse width correction circuit 21 according to light amount correction information. In the past, it was possible to record faithful halftone images by compensating for the effects of variations in the characteristics of each LED and unevenness in the amount of light in the optical system.

Similarly, a pulse-width-modulated halftone image signal is input to the image recording device shown in FIG. 4, and by compensating for variations in exposure amount using voltage value correction (-), a faithful halftone image is recorded. be able to.

FIG. 7 is a block diagram of an image recording apparatus according to still another embodiment of the present invention. In this figure, 24 is a buffer memory for storing image signals for one scanning line;
5 is a time width correction circuit.

The other parts 11 to 16 and 22 are the same as the corresponding parts in FIG. However, the scan clock circuit 14 also generates a control signal for the buffer memory 24.

The binary image signals that are serially input to the input terminal 11 are temporarily stored in the vanofer memory 24. When the image signal for one scanning line is accumulated in the buffer memory 24, the scanning clock circuit 14 allocates the buffer memory 24 by a control signal,
The image signal is read out n times from the buffer memory 24 at a cycle of 1/n of the line period T]T/n, and is manually input to the width correction circuit 25. The scanning clock circuit 14 is synchronized with the readout of this image signal.
22 address number 1 is updated, and the light amount correction information for each LED is outputted from the recoloring ROM 22 n times.

11.1 The welfare positive circuit 25 outputs a pulse with a constant pulse width for the first image signal readout [1-""is, it's all black" image signal, and it on the surface
, if you want to use light-correction information, output a pulse of "black" image signal to the "black" image signal.
Sometimes I don't give out. The amplifier corresponding to each LED in the LED drive amplification circuit 12 amplifies the pulse manually from the time width correction circuit 25.
It is applied to ED as a drive signal. That is, this example ta:,
Run the valley LED blue n times and apply 1 to each LED! ”:h
The gold side time of the pulse width of 1 quantity is the light amount of each LED (1
-8i'Jllt, but by controlling -2,
The idea is to cancel out variations in exposure amount.

In order to simplify the explanation, the case where n=2 will be explained in detail with reference to FIG.

Figures 8a and 8 are Figures 3a and 3, respectively.
As shown in the figure, the brightness Li and light amount correction information T1 for each LED are shown. FIG. 8C is a waveform diagram of a binary image signal, and FIG. 8D is a waveform diagram of a drive signal for each LED.

During the first scanning period of each LED, the time width correction circuit 25 maintains a constant pulse width a for all "black" image signals.
In order to output a pulse of
A drive signal (voltage value is constant) with a pulse width rl is applied to D. In the second scanning period, among the black and white image signals, only the black and white image signals corresponding to the LEDs whose light intensity correction information Ti(c) exceeds the standard value of 100 are given a constant pulse width β. Since it outputs a pulse of (〈α), Fig. 8 d
As shown in FIG. 3, a drive signal having the main pulse width β is applied to the LED with i=3.5.9. That is, the time width α of the drive signal for the LED whose Li value is equal to or greater than the reference value 100,
By increasing the time width of the drive signal for the LED whose Li value is less than the reference value 100 by β to It+β, the same exposure uniformity as in the configuration shown in FIG. 3 is achieved. It should be noted here that if the time division ratio n is shifted by 3 or more, the 1-h width of the drive signal can be more finely corrected, so the exposure compensation accuracy is improved by 1.

In addition, if (as shown by the broken line in Fig. 8), the small amplitude pulse 2 with the same pulses 1i11' and '1α as the first time is
It is also possible to apply it to the LED as a drive signal from the second time onwards.

1, the buffer memory 24 and the ROM 22 are read out in parallel, and the time width correction circuits 26 are arranged in columns of 11[;
First, by operating all 1゛1911= devices in 12 at the same time,
It is also possible to have a similar time span.

For example, as shown in Figure 9, in the first half of the scanning period, all L
Apply a drive signal with a constant pulse width to the ED all at once/Jll L
, (assuming that an all '°black''' stroke code is input; the same applies hereafter), LE whose Ll value is less than the reference value in the latter half of the interval
A drive signal with a narrow pulse width (or a drive signal with the same pulse width and small amplitude as shown by the broken line) is simultaneously applied only to D. Alternatively, as shown in Fig. 10, in the first half of the scanning period, a drive signal with a constant pulse width is applied to all hEDK71s at the same time one fixed number of times, and in the second half, only the LEDs with a small Ll value are applied with the same pulse width (or with a different pulse width). A fixed number of drive signals (pulse width) are applied all at once. In either example, if the number of divisions n of the scanning time is 3 or more, more accurate correction is possible.

When all the L'EDs are driven in parallel in this way, if the exposure amount is constant, the scanning period T can be shortened compared to when each LED is driven in series, and thus the recording speed can be improved.

Although the embodiment has been described above in which correction is performed for each element, it is also possible to make a plurality of elements into one block and perform correction on the average amount of light for each block. When constructing an LED, a plurality of chips having a plurality of elements are connected to form an array of a predetermined length. In such a case, variations in each element within a chip tend to be relatively small, and variations between chips tend to appear large.

Therefore, it is also possible to obtain a correction effect by defining one chip as one block and using the average light i14 to determine the correction value and applying it within the block. In this case, the correction circuit can be simplified.

Although an embodiment using an LED as a light emitting element has been described above, the light emitting element is not limited to an LED. However, instead of direct exposure using a light-emitting element, an 11゛4-component image recording device uses light from a light source to form an image on a photosensitive recording medium using a light amount control element such as an R-type crystal. The invention can be applied in the same way.

Furthermore, in each of the above embodiments, an electrostatic latent image of an image is recorded on a photosensitive leak/drum, and the latent image is developed to obtain a visible image. It is clear that the present invention can be similarly applied to image recording apparatuses that use photosensitive recording media capable of recording images.

3. Detailed Description of the Invention As described, according to the present invention, means for storing light amount correction information for each light emitting element or light amount control element;
Means for correcting the dimensions of each light emitting element, the voltage value or current value of the drive signal for each light amount control element, or the time width, or both, according to the corresponding light amount correction information stored in the above means. By providing this, it is possible to equalize the amount of exposure on the photosensitive recording medium, so that high quality images with uniform recording density can be stored, and
Since it is no longer necessary to strictly suppress variations in the characteristics of the light emitting elements and light quantity control elements and unevenness in the quantity of light in the optical system, the manufacturing yield of these elements can be improved and costs can be reduced.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional image recording device, FIG. 2 is a block diagram showing the configuration of an image recording device according to an embodiment of the present invention, and FIG. 3 is an explanation of the operation of the image recording device shown in FIG. 2. 4 is a schematic diagram showing the configuration of an image recording device according to another embodiment of the present invention, FIG. 6 is an explanatory diagram of the operation of the image recording device shown in FIG. 4, and FIG. 6 is similar to FIG. Operation explanatory diagram when a halftone image signal is input to the image recording device shown in FIG.
9 is a block diagram showing the configuration of an image recording device according to still another embodiment of the present invention, FIG. 8 is an explanatory diagram of the operation of the image recording device shown in FIG. 7, and FIG. 9 is an image FIG. 10 is a waveform diagram for explaining another modification of the image recording apparatus shown in FIG. 7. FIG. 11... Image signal input terminal, 12... LED drive amplifier circuit, 13... LED array section, 13a
...LED array, 13b...optical system,
14... Scanning circuit, 15... Recording section, 15a... Photosensitive sensor/drum, 21...
... Pulse width correction circuit, 22 ... ROM, 23
... Voltage correction circuit, 24 ... Buffer memory, 26 ... Time width correction circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person @1
Fig. 5 Fig. 2 Fig. 3 Fig. 1-6 l No. 4 Meat Fig. 5 □C □6 Fig. 6 111-6 □6 Fig. 7 M8 Fig. 6 ``''''6 ・/2 -Hgekaku 1

Claims (1)

[Claims] Light emitted by each of the number of light emitting elements or light amount control elements or transmitted through each of the light control elements;
An image recording apparatus that records an image corresponding to the image signal on the photosensitive recording medium by exposing the photosensitive recording medium to light, the apparatus comprising an Ail light emitting element
1. An image recording device comprising: means for correcting the width of one space in accordance with corresponding light amount correction information stored in the means.