JPH0829603B2 - Optical recording device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording apparatus for recording an image on a photosensitive recording surface with a large number of optical recording elements.

2. Description of the Related Art As shown in FIG. 3, a conventional device of this type includes a large number of light emitting diode LEDs in the main scanning direction of the electrostatic photosensitive recording surface P.
From the terminal 1, there are a recording element array 4 in which are arranged, a drive circuit 3 for energizing and driving each LED based on an image signal, and a correction circuit 2 for individually correcting the variation of the emitted light amount of each LED. The latent image of the line image is exposed and recorded in the main scanning direction of the photosensitive recording surface P by individually energizing and driving the LEDs in the recording element array 4 based on the pixel information of the input image signal. Was there. The LED driving power is separately supplied from the terminal 5.

In this case, the recording operation is performed for each line. 1
When the image signal for a line is input to the correction circuit 2, the correction circuit 2 adds predetermined correction information to the input image signal. The drive circuit 2 selectively energizes and drives only the LEDs corresponding to the white pixels based on the image signal, and individually controls the energization time for each LED based on the correction information. As a result, the variation in the amount of light emitted from each LED is corrected, and recording is performed with a constant exposure amount.

When the latent image for one line is exposed and recorded, the recording surface P is fed and moved by one line pitch in the sub-scanning direction, and then the latent image for the next line is similarly exposed and recorded. By repeating this operation, a latent image of a two-dimensional image in the main scanning direction and the sub scanning direction is exposed and recorded.

Although not shown, the latent image exposed and recorded as described above is officially recorded through processes such as toner development, transfer to recording paper, and heat fixing.

Problems to be Solved by the Invention However, according to this configuration, the LE circuit is corrected by the correction circuit 2.
Even though the variation in the emitted light amount of D was once corrected, subsequent use causes a large variation over time in the emitted light amount of the LED, which eventually shortens the effective life of the recording element array. There was a problem of doing.

 The above problem occurs for the following reasons.

That is, the amount of light emitted from the LED decreases with the total driving time. It is good if this decline progresses uniformly. However, for example, when an image of a specific pattern such as a format document having vertical ruled lines is continuously recorded, even in the same recording element array 4, it is frequently driven to emit light depending on the LED array position, and other cases. However, it comes out. For example, an LED located where a vertical ruled line of a format document is recorded is significantly more frequently driven to emit light than an LED located elsewhere. When there is a difference in driving frequency in this way, the amount of light emitted from the LEDs at high driving frequencies declines according to the usage time of the recording device, but the amount of light emitted from LEDs at low driving frequencies becomes The decrease is small for the use time, and this causes variations in the amount of emitted light. This variation expands with the use of the recording apparatus, and eventually exceeds the correctable permissible range.

The present invention has been made in view of the above problems,
It is an object of the present invention to provide an optical recording device capable of extending the effective life of a recording element array by reducing the characteristic variation that occurs in an optical recording element such as an LED over time.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention allows a pseudo image signal representing, for example, a white pixel to be added to the end of the image signal, and the length of the pseudo image signal can be variably set. It is equipped with a configuration of.

The present invention can change the positional relationship between the recorded image by the actual image signal and the optical recording element by the above-described configuration, thereby averaging the driving frequency of the optical recording element, and keeping the optical recording element in the elapsed time. It is possible to reduce variations in characteristics that occur as a result, and to extend the useful life of the recording element array.

Embodiment FIG. 1 shows a schematic structure of an optical recording apparatus according to an embodiment of the present invention.

In the figure, first, 6 is a control circuit, 7 is a line counter, 8 is a white addition counter, 9 is a data counter, 10 is a white addition value setting circuit, 11 is a data buffer consisting of RAM, and 12 is a correction circuit. , 13 is a drive circuit, LED is a light emitting diode as an optical recording element, 14 is a recording element array having a large number of LEDs, 15 is a drive power supply terminal, and P is an electrostatic photosensitive recording surface.

The control circuit 6 monitors the state of each part,
The operation of each unit is controlled based on this monitor. The control circuit 6 is composed of a random logic circuit or a microcomputer.

The line counter 7 is activated by a control signal LENB provided from the control circuit 6 and counts a clock φ having a predetermined cycle from a zero value. When the count value reaches a predetermined count end value n, the count end signal LCAY is output to the control circuit 6.
The count end value n is set to be slightly larger than the number of pixels included in the image signal for one line in the main scanning direction.

The white addition counter 8 is activated by the control signal WENB given from the control circuit 6 and counts the same clock φ as described above from a zero value. When the count value reaches a predetermined count end value x, the count end signal WCAY is output to the control circuit 6.
The count end value x is arbitrarily set by the white additional value setting circuit 10.

The data counter 9 is activated by the control signal DENB given from the control circuit 6, and counts the same clock φ as described above from a zero value. When the count value reaches the count end value m, the count end signal DCAY is output to the control circuit 6. The counting end value m is matched with the number of pixels included in the image signal for one line in the main scanning direction. The count value of the data counter 9 is given to the data buffer 11 as an address.

The white additional value setting circuit 10 is configured so that an arbitrary value can be variably set by a dip switch or the like. The set value is the above-mentioned white addition counter 8
Is preset as the count end value x.

The data buffer 11 is an image signal DATA input from the outside.
Is temporarily stored, and the stored image signal DATA is sent to the correction circuit 12. This data buffer 11 is 1 in the main scanning direction.
Every time an image signal for a line is stored, a signal DOR notifying that the image signal can be output is sent to the control circuit 6.
The output operation of the data buffer 11 is commanded by the control signal DENB given from the control circuit 6 together with the counting operation of the data counter 9. When the output operation is instructed, the stored image signal DATA is transferred to the data counter 9
One pixel is output each time the address given by the count value is updated.

The correction circuit 12 generates correction information for individually correcting the variation of the emitted light amount of each LED in the recording element array 14,
This is output to the drive circuit 13 together with the image signal input from the data buffer 11. The input operation of the image signal in the correction circuit 12 is instructed by the control signal LENB given from the control circuit 6 together with the counting operation of the line counter 7.

The drive circuit 13 selectively performs energization drive based on the image signal and sets the energization time based on the correction information.
Control each D individually. As a result, the variation in the amount of light emitted from each LED is corrected, and recording is performed with a constant exposure amount. Power for selectively energizing and driving the LEDs is separately supplied from a dedicated power circuit (not shown) connected to the power terminal 15.

A large number of LEDs as recording elements are arranged in the recording element array 14 in the main scanning direction. In this case, the number of arrays is the same as the count end value n of the line counter 7. In other words, there are slightly more LEDs than the number of pixels for one line.
Are arranged.

The electrostatic photosensitive recording surface P is formed in a drum shape and is rotated and fed in the sub-scanning direction orthogonal to the main scanning direction. Although not shown, a toner developing unit, a transfer unit, and the like are arranged at the rotational movement destination of the recording surface P.

The operation of the optical recording device configured as described above will be described below.

FIG. 2 shows a timing chart of an operation example of the above-mentioned optical recording apparatus.

In FIGS. 1 and 2, first, the data buffer
When the image signal DATA for one line is stored in 11, the signal DOR is sent from the data buffer 11 to the control circuit 6.

Then, the control circuit 6 issues the control signals LENB and WENB.
As a result, the line counter 7 and the white addition counter 8
Respectively start counting the clock φ. At the same time, the correction circuit 12 starts the image signal input operation. However, at this time, the image signal is not output from the data buffer 11. Therefore, the correction circuit 12 receives the white pixel information represented by no signal input as a pseudo image signal. The pseudo image signal is input for each pixel in synchronization with the clock φ.

When the white addition counter 8 outputs the count end value x of the count end signal WCAY, the control circuit 6 cancels the control signal WENB to end the operation of the white addition counter 8 and also outputs the control signal DENB. It commands the counting operation of the data counter 9 and the output operation of the data buffer 11. As a result, the correction circuit 12 receives the actual image signal DATA instead of the pseudo image signal containing only white pixel information. The input of the image signal DATA is performed until the data counter 9 counts the count end value m and issues the count end signal DCAY. The input is performed pixel by pixel in synchronization with the clock φ.

The image signal DATA for one line in the main scanning direction is input to the correction circuit 12, and the count end signal DCAY is output from the data counter 9.
Then, the control circuit 6 cancels the control signal DENB. As a result, the operation of the data counter 9 is ended.

After this, the pseudo image signal by no signal input is input to the correction circuit 12 again in synchronization with the clock φ until the line counter 7 counts the count end value n and issues the count end signal LCAY.

As described above, pseudo image signals each including an arbitrary number (x, n- (x + m) of white pixel information are added to the front and rear ends of the image signal DATA and are input to the correction circuit 12.
Selectively energize and drive the LEDs in the recording element array 14 based on the image signal DATA to which the pseudo image signal is added. As a result, a latent image of a line image in which white pixels are arranged at both ends by pseudo image signals is exposed and recorded on the photosensitive recording surface P.

Here, the number of white pixel information added to the front and rear ends of the image signal, that is, the length (x, n- (x + m)) of the pseudo image signal is determined by the count value x preset in the white addition counter 8. To be Further, the count value x is arbitrarily variably set by the white additional value setting circuit 10. Therefore, by scanning the white additional value setting circuit 10, the positional relationship between the LED and the recorded image based on the actual image signal DATA can be changed. Thereby, for example, the LEDs located where the vertical ruled lines of the format document are recorded can be changed to correct the drive frequency of the specific LED being biased to either high or low.

As described above, in the above-described optical recording apparatus of the actual example, the counters 7, 8, 9 and the control circuit 6 and the like make the pseudo image of an arbitrary length (x, n- (x + m)) at the end of the image signal DATA. A pseudo image signal adding means for adding a signal is configured. By this pseudo image signal adding means, it is possible to change the positional relationship between the recorded image based on the actual image signal DATA and the LED, and average the drive frequency of the LED. As a result, it is possible to reduce variations in characteristics of the optical recording element over time and extend the effective life of the recording element array 14.

Although the light emitting diode LED is used as the optical recording element in the optical recording apparatus of the above-described embodiment, it may be configured to use an optical element such as a liquid crystal shutter or a plasma light emitting element. Further, when a white image is recorded on a black background, the pseudo image signal may be formed by the black pixel information.

As is apparent from the above description, according to the present invention, a pseudo image signal representing, for example, a white pixel is added to the end of the image signal, and the length of the pseudo image signal can be variably set. It is possible to change the positional relationship between the recorded image by the actual image signal and the optical recording element, thereby averaging the driving frequency of the optical recording element and reducing the characteristic variation occurring over time in the optical recording element. Therefore, the effective life of the recording element array can be extended.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic structure of an optical image recording apparatus according to an embodiment of the present invention, FIG. 2 is a timing chart showing an operation example in the main part, and FIG. 3 is a conventional optical recording apparatus. It is a block diagram showing a schematic structure. 6 ... Control circuit, 7 ... Line counter, 8 ... White addition counter, 9 ... Data counter, 10 ... White addition value setting circuit, 11 ... RAM data buffer, 12 ...
... correction circuit, 13 ... driving circuit, LED ... light emitting diode as recording element, 14 ... recording element array, 15 ... driving power supply terminal, P ... electrostatic photosensitive recording surface.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H04N 1/23 103 Z

Claims (3)

[Claims] 1. A recording element array in which a large number of optical recording elements are arranged in the main scanning direction of a photosensitive recording surface, a drive circuit for individually energizing and driving each optical recording element based on an image signal, and An optical recording apparatus having a pseudo image signal adding means for adding a pseudo image signal of an arbitrary length to an end. 2. The optical recording apparatus according to claim 1, further comprising a pseudo image signal adding means for adding a pseudo image signal including an arbitrary number of white pixel information to an end of the image signal. 3. The optical recording apparatus according to claim 1, further comprising a recording element array in which a large number of light emitting diodes are arranged as an optical recording element.