JP3462735B2 - Image forming device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a printer.

[0002]

2. Description of the Related Art In this image forming apparatus, font data based on image information inputted in advance is stored and held in a memory before outputting a character image. The font data consists of, for example, 48 dots per character, but here, for simplification, description will be made assuming that it consists of 8 × 8 dots as shown in FIG. Therefore, as shown in FIG. 2, one character consists of 8 lines (lines in the main scanning direction). A plurality of characters are arranged according to the image information and stored in the memory. However, for the sake of simplicity, description will be given assuming that font data a, b, c, d of four characters are arranged in the main scanning direction.

In the conventional image forming apparatus, as shown in FIG. 5, the memory 40 is stored in the order of 1, 2, 3, ... N lines. That is, the first lines a1, b1, of the font data a, b, c, d shown in FIG.
c1 and d1 are sequentially arranged from the left as the first line of the image data, and the second line a of each of the font data a, b, c and d is set.
2, b2, c2, d2 are sequentially arranged from the left, and the second line of the image data, and third lines a3, b3, c3, d3 of the font data a, b, c, d are sequentially arranged from the left, and the third line of the image data is arranged. It was set as a line, and it was supposed to be memorized in the same way.

When this image data (font data) is output to form an image, for example, when the image forming apparatus is designed to generate four laser beams at the same time, four laser diodes are provided for each. On the other hand, the data stored in the memory has been read in order from the first line and loaded into each buffer.

That is, as shown in FIG. 6, the data of the first line is read from the memory 40 into the buffer A1 for each laser diode, and the data of the second line is next read into the buffer A2 for the second laser diode. Then, the data of the third line is read into the buffer A3 for the third laser diode, and the data of the fourth line is read into the buffer A4 for the fourth laser diode.

The time required during this period is W1. When the data of the fourth line is read into the last buffer A4, the first to fourth laser diodes simultaneously emit light,
Four laser beams corresponding to the data in the buffers A1 to A4 are emitted. These laser beams are irradiated on the photoconductor drum at equal intervals in the sub-scanning direction, and are scanned (scanned) in the main scanning direction.

While an image is being drawn by the laser beam based on the data in the buffers A1 to A4 (W2), another buffer B1 to B4 provided corresponding to each laser diode is provided in the fifth to the fifth memory 40. Eight lines of data are sequentially transferred. Then, in the further next period (corresponding to W3), an image based on the data in the buffers B1 to B4 is drawn, and the ninth to twelfth data stored in the memory 40 is sequentially loaded into the buffers A1 to A4. Less than,
By repeating the above operation, 1 to n lines are formed.
An image of the page (in this case, a latent image) is formed. In this way, the latent image formed on the photosensitive drum is toner-developed by the developing unit and transferred to the sheet by the transfer unit.

[0008]

As described above, the image forming apparatus of the type that draws an image with a plurality of light beams is said to be faster in image formation than the type that draws with a single light beam. There are advantages. However, since the conventional image forming apparatus of this type sequentially performs line-by-line when loading from a memory into a plurality of buffers, for example, in the case of four light beams, one buffer is required to load data into four buffers. It takes four times as long as Therefore, in terms of drawing an image by scanning with four beams at the same time, the time is shortened as compared with the case of one beam, but the time is not shortened with respect to loading the data into the buffer. It was

The present invention has been made in view of the above point, and the time for supplying font data from the memory to the plurality of light beam generating means at the time of image output can be shortened to perform character image output more quickly. It is an object of the present invention to provide an image forming apparatus configured as described above.

[0010]

In order to achieve the above object, according to the invention of claim 1, font data is generated by a light beam.
It is divided into the same number as the number of means in line units in the main scanning direction,
Independently provided for each of the light beam generating means
It may be stored in the data storage unit, the data at the time of image output
Main scanning of multiple divided font data from the data storage unit
Line direction Simultaneously read line by line and swing in the main scanning direction
Simultaneously line up multiple light beams in the sub-scanning direction of the photoconductor
It is characterized by exposing to .

According to a second aspect of the invention, in the image forming apparatus according to the first aspect of the invention, the number of light beams is m, and the corresponding m data storage units are provided in the storage means. It is characterized in that font data of main scanning direction lines is sequentially stored in the form of s, m + s, 2m + s, ... In the sth data storage section.

According to the third aspect of the invention , the phone is
Data in the main scanning direction in the same number as the number of ink ejection means.
The ink ejection process
The data is stored in the data storage section provided for each column and the image is
At the time of image output, a plurality of divided fo
Data is read out line by line at the same time in the main scanning direction.
Line up multiple inks in the sub-scanning direction and simultaneously in the main scanning direction.
It is characterized in that it is discharged to .

The invention described in claim 4 is the same as that of claim 3.
In the image forming apparatus of the invention, the number of the ink ejecting means is m
Then, m corresponding data storage units are installed in the storage means.
The sth data storage section
Next, the font data of the line in the main scanning direction is stored in the form of s, m + s, 2m + s, ....
It is characterized by

The invention described in claim 5 is the same as claims 1 to
The image forming apparatus of the invention of any one of claims 4, before
The data output timing is aligned in each data storage unit.
It is characterized by having a buffer to get it.

[0015]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 is a semiconductor memory that stores and holds input image data. The input image data consists of 1 to n lines per image. However, it is assumed that lines 1 to 8 are formed by sequentially arranging the four font data a to d shown in FIG. 2 from the left in the main scanning direction. The line number of each font data and the line number after arrangement are the same. When this image data is written in the memory, in the present embodiment, the divided data is written into the data storage unit for each shared data of the four laser beams. Here, M1 is a data storage unit for the first laser beam, and similarly M2 and M
Reference numerals 3 and M4 are data storage units for the second, third and fourth laser beams.

As shown in FIG. 3, font data of the 1st, 5th, 9th, ..., (n-3) th line are stored in the data storage section M1. Similarly, the second, sixth, tenth, ..., (n-2) th line font data are stored in the data storage unit M2, and the third,
The font data of the 7th, 11th, ..., (n−1) th line are stored, and the 4th, 8th,
The font data of the 12th, ..., Nth line are stored. In this case, n is an integral multiple of 4.

In this embodiment, the laser beam is changed to 4
Four data storage unit as shown in FIG. 3 because it is the present M1~
The M4 is made to divide and hold the image data by the method described above,
More generally, assuming that the number of laser beams is m, the number of data storage units is also m. For the sth data storage unit, as shown in FIG. 7, s, m + s, The font data of the line in the main scanning direction is stored in the form of 2m + s, ....

Regarding the method of writing to the memory 1, any method may be used. Therefore, there is no problem even if it takes time by writing the input image data while dividing the input image data line by line. This is because the input of image data (storage in memory) and the output of image (image formation) are not always performed integrally (sequentially), and the image output is performed when input is required. This is because it is sufficient to speed up the process of doing.

The point is that the font data stored in the memory 1 is stored corresponding to each laser beam as described above, and each font data corresponding to each of a plurality of laser beams can be read from the memory 1 at the same time. It should be like this. However, if there is a method that can quickly write to the memory 1 while maintaining such a relationship,
It goes without saying that the method may be adopted, and in that case, the time from the image input to the image output can be shortened.

In FIG. 1, A1 and B1 are buffers for the first laser beam, A2 and B2 are buffers for the second laser beam, A3 and B3 are buffers for the third laser beam, and A4 and B4 are buffers. A buffer for four laser beams. When font data is simultaneously loaded from the data storage units M1, M2, M3, and M4 into the buffers A1, A2, A3, and A4 (time period T1 in FIG. 4), the font data is simultaneously output from the buffers B1, B2, B3, and B4. To do. In the next period T2, the buffers B1, B2, B3,
Font data is simultaneously fetched from the data storage units M1, M2, M3, and M4 into B4 and stored in the buffers A1, A2, and A.
Font data is output from A3 and A4 at the same time.

That is, when the font data is loaded into the buffers A1 to A4, the first line font data stored in the data storage unit M1 shown in FIG. 3 is stored in the buffer A1 and the data storage unit M2 is stored in the buffer A2. The second line font data stored therein, the buffer A3 stores the third line font data stored in the data storage unit M3, and the buffer A4 stores the fourth line font data stored in the data storage unit M4. It is taken in at the same time.

Similarly, when the font data is loaded into the buffers B1 to B4, the data storage unit M is stored in the buffer B1.
1 to 5th line font data, buffer B2 from data storage unit M2 to 6th line font data, buffer B3 from data storage unit M3 to 7th line font data, buffer B4 from data storage unit M4 The font data of the eighth line is taken in at the same time. By doing so, the period of T1, T2 ... Is shortened to 1/4 as compared with the periods W1, W2 ... Of FIG.

The buffers A1 to A4 and B1 to B4 are introduced to align the output timing of the font data and to match the operation timings of the laser diodes 11 to 14 and to match the impedance. The buffers A1 to A4 and B1 to B4 may be deleted as long as they can match the operation timings of the laser diodes 11 to 14.

L1, L2, L3, and L4 represent laser beams generated from the laser diodes 11, 12, 13, and 14, respectively. These beams are condensed using a lens system (not shown), and the surface of the photosensitive drum 16 is scanned by the polygon mirror 15 in the main scanning direction.
Further, by rotating the drum 16, scanning in the sub-scanning direction can be obtained.

In this way, the electric latent image drawn on the photoconductor drum 16 is developed with toner by a developing unit (not shown) arranged around the drum, and is transferred to a sheet by a transfer unit (not shown). After being transferred to, it is fixed by a fixing unit (not shown),
It is discharged from the image forming apparatus.

In FIG. 1, laser diodes 11 to 11 are shown.
Considering the case of using an inkjet that ejects ink instead of 14, it is possible to form an image on the paper by directly facing the paper instead of the photoconductor drum.

Reference numeral 17 denotes a main control unit including a CPU, which includes the memory 1 and the buffers A1 to A4 and B1 to B.
Controls writing and reading of No. 4. Further, the main control unit 17 communicates data with the operation unit / display unit 18 to issue a command associated with the operation of the operation unit, process data, and display on the display unit.
Further, the main control unit 17 is also connected to the scanner unit 19 and the host computer 20, and processes the image data from the scanner unit 19 and the host computer 20 to give it to the memory 1.

[0028]

As described above, according to the present invention, even when there are a plurality of light beams and ink ejecting means at the time of outputting font data, it is possible to output a plurality of font data at the same time. There is an effect that the font data output processing speed becomes faster as a whole.

[Brief description of drawings]

FIG. 1 is a block diagram of a main part of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing font data.

FIG. 3 is a diagram showing a form of font data storage in a memory according to the present embodiment.

FIG. 4 is a diagram showing fetching of font data from a memory to a buffer in this embodiment.

FIG. 5 is a diagram showing fetching of font data from a memory to a buffer in an image forming apparatus of a conventional example.

FIG. 6 is a diagram showing a form of font data storage in a conventional memory.

FIG. 7 is a diagram showing a mode in which font data is stored in a memory corresponding to m light beams or m ink ejecting means in the present invention.

[Explanation of symbols]

1 memory M1, M2, M3, M4 data storage A1-A4 buffer B1-B4 buffer 11-14 Laser diode L1-L4 laser beam 15 polygon mirror 16 photoconductor drum 17 Main control section

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Claims (5)

(57) [Claims] 1. The font data is used as the number of light beam generating means.
It is divided into the same number line by line in the main scanning direction.
It said light beam generating means provided data storage by the falling
Parts may be stored in either the data storage unit when an image output
The main scanning direction lie Luo plurality of divided font data has been
Multiple units that are simultaneously read out in units of
An image forming apparatus that simultaneously exposes a light beam in the sub-scanning direction of a photoconductor . 2. The number of light beams is m, and m data storage sections corresponding thereto are provided in the storage means, and s, m + s, 2m + s, ... Sequentially to the sth data storage section. The image forming apparatus according to claim 1, wherein font data of a line in the main scanning direction is stored in the form of. 3. The font data is the same as the number of ink ejecting means.
Number in the main scanning direction line by unit, each independent
In the data storage unit provided for each of the ink ejecting means and stored in the data storage unit at the time of image output.
The number of divided font data in the main scanning line direction
Along a plurality of ink in the sub-scanning direction is read simultaneously in position
An image forming apparatus that simultaneously discharges in the main scanning direction . 4. The ink ejecting means is m in number, and m corresponding data storage sections are provided in the storage section, and s, m + s, 2m + s ,. The image forming apparatus according to claim 4, wherein the font data of the line in the main scanning direction is stored in the form of. 5. Outputting data to each of the data storage units
I added a buffer to adjust the timing
The image according to any one of claims 1 to 4, characterized in that
Forming equipment.