JPS607263A - Printer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plinking device that uses controlled pulse width modulation to control the diameter of a recording dot in an electrophotographic printer that attempts to express 111 dot sizes in one recording dot. It is.

Conventionally, in this type of coloring, as shown in FIG. 1, a laser tie auto 1 performs pulse width modulation according to the density signal of the recorded information, controls the on/off of the laser beam, and rotates the lens system 21 rotating mirror 3°. Photoreceptor 5 via lens 4
A latent image intensity distribution as shown in FIG. 2(b) corresponding to the pulse width shown in FIG. 2(a) is obtained on the zero surface, and when this electrostatic latent image is faithfully developed with toner. The toner adheres to an amount exceeding the threshold value S, and the number of recorded dots shown in FIG. 2 (CC) can be written. By controlling the laser diode 1 in this way by adjusting the pulse width f,
Recording dot diameter can be controlled.

That is, as shown in FIG. 2(a), the falling edge of the pulse is 6a.
In this case, as shown in Figure 2(b), the falling edge of the a image intensity is 6b.
As shown in FIG. 2(c), a dot 6C is recorded corresponding to the threshold value SIC. Similarly, when the pulse falls at 7a, the latent image intensity also falls at 7b, and 7c is recorded.

However, pulse width control is based on the rise of the pulse,
In other words, the on/off timing is kept constant, and the pulse width is varied according to the density information of the recording dots, so that the recording dots follow the pulse train (dot row) as shown in FIG. The interval between the recording dots changes depending on the density. For example, if the matrix expression is to be expressed with two tones, the distance between the recording dots changes as shown in Figure 3 (b ), the recording dots are not dispersed within the VC matrix, and depending on the recording pattern, the density υ etc. may occur.

In order to eliminate this drawback, the present invention controls the pulse width as well as the rise time of the pulse when performing laser beam pulse width modulation, and records the recording dots.
It is made so that the distance between the center of the throat is always one foot. This invention will be explained in detail below.

The fourth problem is a printer controller IQY, which is an embodiment of the present invention, in which 11 is a buffer for storing information about the recording dots to be recorded, and 12 is a buffer memory 11 that stores information about the recording dots to be recorded. a laser diode driver that controls the laser diode 1 according to a signal from a generator 12 to control the recording dot diameter according to the density information obtained;
14 is a control section. Note that 1 and 2 represent the laser diode and lens system shown in FIG.

Next, to explain the operation, when data with multi-level concentration information is input, it is temporarily stored in the buffer 7 memory 11,
Since the density information is sequentially extracted for each pixel, the pattern generator 12 generates a pulse generation pattern corresponding to the density information.
, and input it to the laser diode driver 13 as a laser diode 10 control signal.

Now, as an example, we will take up a case where the density gradation per recording ton, which can be expressed by a pulse width of 7R levels, is four levels. The contents of the pattern generator 12 are the pulse delay time and pulse width as shown in FIG. 'j' That is, the pattern generator 12 changes the pulse delay width to 5 pulses such as 1/3 pulse, 1/6 pulse, and 0 pulse, corresponding to the density information 10' to '3'.
After selecting , the pulse width is set to 72 to output 1/3 pulse, 2/3 pulse, and 1/1 pulse. 5] This information can be easily generated using the information discriminating means, the pulse delay width determining means, the pulse width determining means, and the output means. It can also be realized using a computer.

When recorded according to the present invention according to the manual information shown in FIG. 6(a), the 6th pulse width is recorded as shown in FIG.
The recording result shown in Figure (e) is shown. This means that compared to section 1 of Article 3 (b) when the conventional method is used under the conditions of 1.], the 6 self-recorded dots are dispersed, and the dots are evened out even more than when recording. I take it.

In addition, the distance between the centers of the hC recording dots is always maintained at one foot, and there is a young fruit that prevents uneven recording due to fragmentation of the recording dots.

As described in detail above, according to the present invention, the centers of the recording dots can be set at constant intervals.

Monochrome gradation recording Q) In addition to color gradation recording
can also be applied. 1- That is, in the color scale IA iB record, 19 colors are expressed by mixing four inks of yellow, cyan, magenta, and black, but depending on the degree of overlapping of the inks, for example, 5 as shown in (a), and 5 as shown in FIG. 7(b).
In this invention, both have the same size:
1-YK, magenta Mft of the same size are overlapped, but the color tone looks different (in Fig. 7 (a), when the diameter of the recording dots changes, the pitch between the recording dots changes, resulting in color shift. It causes the occurrence of.

However, in Figure 947 (b), the pinch is constant, so there is no need to worry about color shift due to overlapping color dots (furthermore, since the center is constant, even when colors are expressed in a matrix, they are averaged better than before). It has the advantage of being able to record images without unevenness.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of a conventional electrophotographic recording method using a laser diode, and Figures 2 (1,) to <C) are for explaining the concept of controlling the recording dot diameter by conventional pulse width modulation. Figures 3(a) and 3(b) are diagrams showing the relationship between the dot array and the noxle array based on the conventional pulse width variation of -4, as well as the intermediate adjustment of matrix recording. A block diagram showing the configuration of the blink controller which is the main part of one embodiment, FIG. 5 is a diagram showing the internal structure of the pattern generator and a recording example, and FIGS. 6(a) to (c) are the input information according to the present invention. pattern, pulse waveform, and recording results, respectively. 7(a) and 7(b) are diagrams illustrating a conventional example and an example according to the present invention showing the overlapping state of ink. In the figure, 1 is a laser diode, 2 is a lens system, 3 is a rotating mirror, 4 is a lens, 5 is a photoreceptor, 10 is a printer controller, and 11 is a buffer memory. 12 is a butter/generator, 13 is a laser diode driver, and 14 is a control section. Figure 1 Figure 2 Figure 3 (a) 11 1 1 (11 (A) - (b) Figure 6 (a) (b) Figure 7 (a) (c) (b)

Claims (1)

[Claims] The laser beam is scanned, the recording dot diameter is controlled using the pulse width modulation 7 of the laser diode, and the density gradation is performed for each recording dot. , a printer characterized in that it is equipped with a vacuum generator that controls the rise time and pulse width of the laser diode pulse according to the density information of one recording dot, and keeps the interval between recording dots constant regardless of the dot size. Device.