JPH02137947A - Image recorder - Google Patents

Abstract

PURPOSE:To expose an image carrier with an optical beam to become white/ black dot becoming a desirable independent one dot and to record an image having excellent reproducibility by generating an image signal having a plurality of times of scanning density on the basis of stored content of memory means for storing image information of 3 lines of scanning lines in a sub scanning direction, and controlling the exposing scanning position and diameter of the beam on the basis of the signal. CONSTITUTION:Memory means 1 is composed, for example, of three shift registers 21-23 to store 3 scanning lines of image information of one main scanning. A double density converter 2 doubles the scanning density of matrix process to increase the area of the independent dot at the output signal X of an independent dot discriminator 3 and the pixel signal Y of a pixel to be noted. A controller 4 used also as control means exposes to scan the predetermined position of a photosensitive drum as a recording medium and the beam of a predetermined diameter on the basis of the image signal 11 generated after matrix process by the converter 2, and exposes to extend (white/black) the independent one dot.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) This invention is applicable to, for example, laser printers, LED printers,
The present invention relates to an image recording device such as a liquid crystal printer that records an image on a recording medium according to an image information signal by digitally irradiating a light beam.

(Prior art) Conventionally, a light beam is modulated based on digitized image information from an electronic computer, etc., and the modulated light beam is imaged on a recording medium by an optical element such as a light deflector or lens. 2. Description of the Related Art Devices that record image information by scanning are widely known.

In these devices, irradiation or non-irradiation of a light beam onto a recording medium is controlled according to image information. In the image exposure method (hereinafter referred to as the IE method), the exposed portion is visualized and recorded as an image, and the background exposure method (background exposure method; hereinafter referred to as the IE method)
In the round exposure method (hereinafter referred to as the BGE method), an image is recorded by visualizing a non-exposed area.

[Problem to be solved by the invention]

However, in such a method of recording image information on a recording medium using a light beam, an isolated dot of an irradiated area in a continuous non-irradiated area, or conversely, an isolated 1 dot of a non-irradiated area in a continuous irradiated area. Dots may have low reproducibility.

In the former case, in the IE method, it corresponds to a black dot, and in the BGE method, it corresponds to a white dot in the solid area, and in the latter case, in the IE method, it corresponds to a 1 dot in the solid area. This corresponds to a white dot, and in the BGE method, it corresponds to a single black dot.

Hereinafter, the decrease in reproducibility of an isolated single dot will be explained with reference to FIG.

FIG. 8 is a light amount/potential correlation diagram explaining the reproducibility reduction characteristic of an isolated single dot, and FIG. (b) shows the case of one unirradiated isolated dot in a continuous irradiated area, and (C) of the same figure shows the case where the irradiated area and the non-irradiated area are continuous. Note that the upper row in the figure shows the amount of light, and the lower row shows the potential.

The case of isolated single dot irradiation in Figure 8(a) and the same figure (C)
Comparing the case where the irradiated area and the non-irradiated area are continuous as shown in Figure 2, there is a difference in the light intensity for isolated 1 dot irradiation and continuous irradiation, and the isolated 1 dot irradiated area is better than the continuous irradiated area. The amount of light is smaller than that, and the potential does not drop to the continuous irradiation area potential during continuous irradiation. This difference in light amount is shown in Figs. 9(a) and (b).
), in the case of continuous irradiation, the amount of light is integrated, so this occurs because the total amount of irradiated light is larger than that for one isolated dot. As a result, the potential of the image carrier becomes higher, with the isolated one-dot irradiation part potential VLI being higher than the continuous irradiation part potential (2).

For this reason, when the image on this image carrier is visualized, there is a difference between the continuous irradiation area and the isolated 1-dot irradiation area, and the reproducibility of the isolated 1-dot irradiation area becomes low. Also,
Even when a substance that directly develops color when exposed to light, such as photographic paper, is used as an image carrier, the degree of color development varies due to differences in scene distribution, as shown in Figures 8 (a) to (C). The difference is that the reproducibility of isolated single dots becomes low.

In the case of one dot not being irradiated in the continuous irradiation area shown in Fig. 8(b), the light intensity of the continuous irradiation area is similarly integrated, so the light intensity of the non-irradiation area cannot be lowered sufficiently and the reproducibility of the single unirradiated isolated dot is There was a serious problem that the amount of water was extremely low.

The present invention was made in order to solve the above-mentioned problems, and is applicable to a plurality of scanning lines in an image recording apparatus that scans a light beam on a recording medium based on image information and records image information. The purpose of the present invention is to obtain an image recording device that can greatly improve the reproducibility of an isolated dot by extracting an isolated point of one dot from image information immediately before scanning and expanding the area of the isolated point of the L dot. do.

(Means for Solving the Problems) An image recording apparatus according to the present invention includes a storage means for storing image information for at least three scanning lines in the sub-scanning direction;
A generation means for generating an image signal for actual irradiation in which the scanning density of a unit pixel is multiplied by a plurality of times based on the memory contents stored in the storage means; The apparatus is provided with a control means for controlling the exposure scanning position of the light beam scanned on the recording medium and the beam diameter of the light beam for each exposure scanning position.

(Operation) In this invention, input image information for at least three scanning lines in the sub-scanning direction is temporarily stored in the ↑, q means, and the adjacency relationship on the image information is examined to extract one isolated dot. Then, the generation means generates an image signal for actual irradiation in which the scanning density of one dot is multiplied by a plurality of times based on the memory contents stored in the storage means. The exposure and beam diameter of the light beam are controlled based on the image signal, and the area of the single isolated dot is enlarged by scanning multiple times the scanning density, thereby improving the reproducibility of the single dot.

(First Embodiment) FIG. 1 is an enlarged scanning information processing circuit diagram in an image recording apparatus showing an embodiment of the present invention. Reference numeral 1 denotes a storage means, which is composed of, for example, three shift registers 21 to 23. , image information for one main scan is stored for three scan lines. 2 is a double-density conversion unit which doubles the scanning density of the output signal X of the isolated dot determination unit 3 and the pixel signal Y of the pixel of interest (P1 in the figure) by matrix processing shown in FIG. Expand the area. Reference numeral 4 denotes a controller which also serves as a control means, which converts an image signal 11 generated from the double-density conversion unit 2 after matrix processing (described later) into a recording medium (not shown).
Expand the isolated L dot by scanning and exposing the light beam at a predetermined position on the photosensitive drum and with a predetermined beam diameter (white/black)
Expose to light.

FIG. 2 is a detailed diagram showing an example of the isolated dot determination unit 3 shown in FIG. EX-N of image information of 8 neighboring signal bits 22 to P8 (adjacent pixels).

R is calculated and the output signal X is output to the double-density conversion section 2.

FIG. 3 is a schematic diagram illustrating matrix processing by the double-density conversion unit 2 shown in FIG. (b) corresponds to the case where the combination of output signal X and pixel signal Y is (0,0), and (e) of the same figure corresponds to the case where the combination of output signal This corresponds to the case (1, 1), and (d) in the figure corresponds to the case where the combination of the output signal X and the pixel signal Y is (o, H).

Next, the operation shown in FIG. 1 will be explained.

The image signals are sequentially transferred from shift register 21 to shift register 22 . The receiver is passed to the shift register 23. At this time, the determination of isolated dots focuses on the signal bit Pl.

When this signal bit PI is ON, adjacent signal bits 22 to P9 are OFF or signal bit P1 is OFF.
When the adjacent signal bits P2 to P9 are in the ON state, the signal bit P1 is determined to be an isolated dot, and the resulting output signal X is set to "1"; otherwise, the output signal Set it to "0".

At this time, the output signal X and the pixel signal Y are manually input to the double-density conversion section 2. Therefore, the double-density conversion unit 2 determines the content, ie, the combination, of the output signal X and the pixel signal Y, doubles the scanning density, and enlarges the area of one isolated dot.

In particular, in FIG. 3, the odd numbered columns of the ■ to L rows, the ■row, and the 2nd row are the main scanning lines corresponding to the original image, and the even numbered columns of the 1st row, the 2nd row, and the 5th row, the Lth row. is an auxiliary scanning line.

For example, when the input signal pair (X, Y) is (0°0), that is, when it is an OFF signal that is not an isolated point,
), the bit signal string advances by two bits as is. Also, the signal pair (X.

When Y) is (1, O), that is, when it is an ON signal that is not an isolated point, the bit signal string has two bits of pixel number It, 12 inverted, as shown in FIG. 3(a), that is, If the input signal is "L", it becomes "0", and if it is "O", it becomes "1".
It will be converted to and proceed.

On the other hand, as shown in FIG. 3(C), the input signal pair (
When x, y) is (1, 1), that is, one isolated dot is ON
In this case, pixel numbers 11 to I3 are inverted, and pixel numbers J1 to J3 corresponding to the auxiliary scanning lines are also inverted. In this way, ON signals for 1.5 dots are obtained. Further, as shown in FIG. 3(d), the input signal pair (x).

Y) is (0, 1), that is, when one isolated dot is OFF, pixel I3. J4. Kl, 2. 3, L1~L
Flip 4. By doing this, two bits after the signal string is sent, that is, when the signal bit at pixel number 3 is sent to pixel number 11, or when the signal bit at pixel number
For example, when the signal bits in x.

Since Y) is (1, O), each is inverted and becomes 1.5
OFF signals corresponding to dots can be obtained. By performing the above processing, it is possible to obtain an image signal in which the area of an isolated L dot is enlarged by 1.5 dots in both directions at double density in the main scanning and sub-scanning amount directions.

When the light beam is scanned based on the image signal for actual scanning generated in this way, scanning with an enlarged pixel area can be realized as shown in FIG.

FIG. 4 is a schematic diagram showing an example of exposure scanning according to the present invention, in which k, 1. m indicates the main scanning line (main scanning line), kl, 1
．． , m indicate auxiliary scanning lines.

As shown in FIG. 4(a), when the isolated dot determination unit 3 determines that the dot A on the main scanning line l is an isolated one dot ON, the dot A is first placed on the main scanning line l for an exposure time of 1. It is extended by .5 times and exposed as shown in FIG. Then, on the next auxiliary scanning line 1+, 1.5 dots are exposed in the same way as on the main scanning line 1, and finally the exposed area is expanded as shown in Figure 4 (C), and the spots are no longer overlapped. The amount of exposure increases significantly. By expanding the exposed area and increasing the exposure amount in this way, the write potential vL of the image carrier is also sufficiently reduced, and the reproducibility of an isolated single dot is improved.

On the other hand, in the case of one isolated dot being OFF, the next dot is turned ON on the main scanning line 1 by 0.5 dots, and the main scanning line m is also turned OFF in the same way as on the main scanning line 1. Furthermore, by turning on the upper auxiliary scanning line m according to the original image information, it became possible to enlarge the non-exposed area.

[Second Embodiment] In the first embodiment described above, the spot diameter of the light beam is set according to the original image information density, and only the scanning density is doubled. As shown, the area of one isolated dot can be expanded by using a spot diameter that corresponds to the actual scanning density, that is, twice the density of image information.

FIG. 5 is a schematic diagram showing another example of spot exposure according to the present invention. Reference numeral 51 indicates a spot corresponding to one dot of image information.
Four beam spots 52 having a spot diameter of 4 are formed. 53 indicates an enlarged isolated dot.

And actually, by the matrix processing shown in Fig. 6,
An isolated dot 53 is formed on the image carrier by expanding the exposed or non-exposed area by one dot of the double-density scan in the main and sub-scanning directions, thereby improving the reproducibility of the single isolated dot.

(Third Example) In the first and second examples described above, the spot diameter of the scanning light beam was constant, but as shown in FIG. The exposure area of one isolated dot can also be expanded by changing the spot diameter.

FIG. 7 is a schematic diagram showing still another example of spot exposure according to the present invention, where 55 indicates a spot of one non-isolated dot, and 56 indicates a spot of one isolated dot.

In the case of non-isolated dots, the scanning light is applied to the main scanning line k with a spot diameter corresponding to the density of the original image information.

1. Expose over m, and add to the auxiliary scanning line, 1. , m.

Perform an empty scan. On the other hand, when it is determined that the isolated dot is ON, eight dots around it are also turned ON (spot 56) with a spot diameter corresponding to the doubled scanning density. Furthermore, when an isolated dot is OFF, by turning OFF the surrounding eight dots, it is possible to enlarge the exposed or non-exposed area and improve reproducibility.

Note that when an isolated dot is enlarged, a good isolated dot can be generated with good reproducibility without the center of the dot being shifted.

Further, the scanning density is not limited to twice the image information density, and basically, scanning may be performed at multiple times.

Further, in each of the above embodiments, the preferred case where the present invention is mainly applied to a laser beam printer etc. has been described, but an image recording apparatus such as an LED printer or an LCD printer that exposes an image carrier with a digitalized optical signal. If so, it goes without saying that the above invention can be easily applied.

(Effects of the Invention) As explained above, the present invention includes a storage means for storing image information for at least three scanning lines in the sub-scanning direction;
A generation means for generating an image signal for actual irradiation in which the scanning density of a unit pixel is multiplied by a plurality of times based on the memory contents stored in the storage means; Since a control means is provided for controlling the exposure scanning position of the light beam to be scanned on the recording medium and the beam diameter of the light beam for each exposure scanning position, the light beam can be used to form a white/black dot with good isolated dots. The image bearing member can be exposed to light, and an image with excellent reproducibility can be recorded.

[Brief explanation of the drawing]

FIG. 1 is an enlarged scanning information processing circuit diagram in an image recording apparatus showing an embodiment of the present invention, FIG. 2 is a detailed diagram showing an example of the isolated dot determination section shown in FIG. 1, and FIG. 1st
4 and 6 are schematic diagrams illustrating an example of exposure scanning according to the present invention, and FIG. 5 is a schematic diagram illustrating another example of spot exposure according to the present invention. 7 is a schematic diagram showing still another spot exposure example according to the present invention, FIG. 8 is a light amount/potential correlation diagram illustrating the reproducibility reduction characteristic of an isolated single dot, and FIG. 9 (a
) and (b) are diagrams showing light quantity characteristics for continuous irradiation. In the figure, 1 is a storage means, 2 is a double-density conversion section, 3 is an isolated dot determination section, 4 is a controller, and 21 to 23 are shift registers. To (X, Y)> (oO) (Ol) O inversion O non-processing diagram (C) (Oo) (ol) O inversion O non-processing diagram procedural correction (t (spontaneous) Heisei

Claims (1)

[Claims] An image recording apparatus that records an image by scanning a light beam on a recording medium based on image information includes a storage means for storing image information for at least three scanning lines in a sub-scanning direction; generating means for generating an image signal for actual irradiation in which the scanning density of a unit pixel is multiplied by a plurality of times based on the stored content; An image recording apparatus comprising: an exposure scanning position of a scanning light beam and a control means for controlling a beam diameter of the light beam for each exposure scanning position.