JPH11129524A - Image-forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image-forming apparatus which shortens a feed time of data to a plurality of light beam generation means from a memory when images are to be output, thereby enabling the images to be output more speedily. SOLUTION: Four laser beams L1, L2, L2, L3 are generated and scanned simultaneously based on respective independent image data, thereby forming images on a surface of a photosensitive drum 16. Input image data are separately held at data memory parts 1a-1d of a memory 1 correspondingly to four laser diodes 11-14. When the image data are to be output, a plurality of the divided image data are read out simultaneously from the memory 1 and fed to corresponding laser diodes 11-14.

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 digital electronic copying machine, a printer and a facsimile machine.

[0002]

2. Description of the Related Art In these image forming apparatuses, input image data is stored in a memory before outputting the image data. The image data is composed of n lines (lines in the main scanning direction) as shown in FIG. 4, but the memory 40 has the order of 1, 2, 3,... Is stored.

When the image data is output to form an image, for example, if the image forming apparatus is configured to generate four laser beams simultaneously, each of the four laser diodes is stored in a memory. The stored data is read out sequentially from the first line and taken into each buffer.

That is, data of the first line is read from the memory 40 into the buffer A1 for each laser diode, and then data of the second line is read into the buffer A2 for the second laser diode. The data of the third line is read into the buffer A3, and the data of the fourth line is read into the buffer A4 for the fourth laser diode.

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

In the next W2 period, while an image is being drawn by the laser beam based on the data in the buffers A1 to A4, the other buffers B1 to B4 provided corresponding to the respective laser diodes store the data in the memory 40. 5th to 8th
Line data is sequentially transferred. Then, in the next W3 period, 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 are sequentially taken into the buffers A1 to A4. Hereinafter, such an operation is repeated to form a one-page image (in this case, a latent image) composed of 1 to n lines. As described above, the latent image formed on the photosensitive drum is developed with toner in the developing unit, and is transferred to a sheet in the transfer unit.

[0007]

As described above, an image forming apparatus of the type in which an image is drawn by a plurality of light beams is capable of forming an image faster than a type in which an image is drawn by a single light beam. There are advantages. However, in this type of conventional image forming apparatus, when data is taken from a memory into a plurality of buffers, the data is transferred one line at a time. For example, in the case of four light beams, data is taken into four buffers in one buffer. It takes twice as long. Therefore, 4
In terms of drawing an image by scanning with a single beam at the same time,
Although the time is shortened as compared with the case of the book, the time is not shortened in taking the data into the buffer.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and is intended to shorten the time for supplying data from a memory to a plurality of light beam generating means at the time of image output so that image output can be performed more quickly. It is an object of the present invention to provide an image forming apparatus according to the present invention.

[0009]

According to the first aspect of the present invention, a plurality of light beams are simultaneously generated and scanned based on independent image data to form an image on an image forming surface. In the apparatus, input image data is divided and held in storage means corresponding to the plurality of light beam generating means, and the plurality of divided image data are simultaneously read out from the storage means at the time of outputting image data, and the corresponding light beam generating means is read out. It is characterized in that it is given to.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect of the present invention, the number of light beams is m, and the corresponding m data storage units are provided in the storage means. s, m are sequentially stored in the s-th data storage unit.
+ S, 2m + s,... Are stored in the memory in the main scanning direction. According to a third aspect of the present invention, in the image forming apparatus of the first or second aspect, the light beam generating means is constituted by a laser diode that generates a laser beam, and an electric latent image is formed on the surface of the photoconductor. And

According to a fourth aspect of the present invention, there is provided an image forming apparatus for forming an image on a sheet by discharging ink from a plurality of ink discharging means based on independent image forming data. The storage means is divided and held in correspondence with the plurality of ink ejection means, and the plurality of divided image data are simultaneously read out from the storage means and output to the corresponding ink ejection means when outputting image data. . According to a fifth aspect of the present invention, in the image forming apparatus according to the fourth aspect of the present invention, the number m of ink ejection units is m, and the number m of data storage units corresponding to the m units is provided in the storage unit. , The data of the main scanning direction line are sequentially stored in the memory in the form of s, m + s, 2m + s,...

[0012]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a semiconductor memory that stores and holds input image data. It is assumed that input image data is composed of 1 to n lines for one image. When writing the image data into the memory, in the present embodiment, the shared data of each of the four laser beams is
It is divided into two and written. Here, reference numeral 1a denotes a data storage unit for the first laser beam.
b, 1c and 1d are data storage units for the second, third and fourth laser beams.

The data storage section 1a stores first, fifth, ninth,
.., The data of the (n-3) th line is stored. Similarly, the data storage unit 1b stores the second, sixth, tenth,.
, The data of the (n-2) th line are stored, and the third, seventh, eleventh,..., (N-
1) Data of the line is stored, and data of the fourth, eighth, twelfth,..., Nth lines are stored in the data storage unit 1d. In this case, n is an integer multiple of 4. still,
In the present embodiment, since four laser beams are used, the image data is divided and held in the four data storage units 1a to 1d by the above-described method as shown in FIG. Is m, the number of data storage units is also m, and divisional storage of image data in those data storage units is performed as shown in FIG.

Regarding the method of writing to the memory 1, any method may be used. Therefore, there is no problem even if it takes time to write the input image data while sequentially dividing the image data line by line. This is because the input of an image (storage in a memory) and the output of an image (image formation) are not necessarily performed integrally (sequentially). This is because the object of the present invention is to increase the speed in such a case.

The point is that the data stored in the memory 1 is stored corresponding to each laser beam as described above, so that each data corresponding to each of the plurality of laser beams can be read from the memory 1 at the same time. It just needs to be. However, if there is a method that can quickly write data into the memory 1 while maintaining such a relationship, it goes without saying that the method may be adopted, and in that case, image input to image output ends. It is possible to shorten the time until

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 for the third laser beam. This is a buffer for four laser beams. When the buffers A1, A2, A3, A4 are simultaneously taking data from the data storage units 1a, 1b, 1c, 1d (period T1), the buffers B1, B2,
Data is simultaneously output from B3 and B4. Next period T2
Indicates data storage units 1 in buffers B1, B2, B3, and B4.
Data is simultaneously taken in from a, 1b, 1c, and 1d, and data is simultaneously output from buffers A1, A2, A3, and A4.

That is, as shown in FIG.
When data is first taken into A4, data of the first line is stored in buffer A1, data of the second line is stored in buffer A2, data of the third line is stored in buffer A3, and data of the fourth line is stored in buffer A4. Captured at the same time.
When data is first taken into the buffers B1 to B4, the data of the fifth line and the buffer B are stored in the buffer B1.
2, data on the sixth line, data on the seventh line into buffer B3, and data on the eighth line into buffer B4 are simultaneously loaded. By doing so, T
The period of 1, T2,... Is reduced to 1/4 of the period of W1, W2,.

The buffers A1 to A4 and B1 to B4 are used to make the data output timing uniform and to match the operation timing of the laser diodes 11 to 14 and to match the impedance. Diodes 11-1
The buffers A1 to A4 and B1 to B4 may be deleted if the operation timing can be matched with the operation timing of No. 4.

L1, L2, L3, and L4 indicate laser beams generated from the laser diodes 11, 12, 13, and 14, respectively. These beams are condensed using a lens system, and the surface of the photosensitive drum 16 is scanned by the polygon mirror 15 in the main scanning direction. In addition, scanning in the sub-scanning direction is obtained by rotation of the drum 16.

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

In the above description, an electrophotographic image forming apparatus has been described as an example. However, in the case where the present invention is applied to an ink jet type image forming apparatus, ink discharging means is used instead of the laser diodes 11 to 14 in FIG. An image can be formed on a sheet by directly opposing the sheet (sheet) instead of the photosensitive drum.

Reference numeral 17 denotes a main control section including a CPU, and the memory 1 and buffers A1 to A4, B1 to B
4 controls writing and reading. Further, the main control unit 17 communicates data with the operation unit / display unit 18 to issue a command accompanying operation of the operation unit, perform data processing, 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 image data from the scanner unit 19 and the host computer 20 and supplies the processed image data to the memory 1.

[0023]

As described above, according to the present invention, even when there are a plurality of light beams and ink ejection means at the time of outputting image data, a plurality of data can be output at the same time. This has the effect of increasing the data output processing speed.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing a mode in which the input image data is stored in a memory;

FIG. 3 is a diagram showing a form in which image data is taken from a memory to a buffer.

FIG. 4 is a diagram showing a storage state of image data in a memory in a conventional image forming apparatus.

FIG. 5 is a diagram showing the capture of image data from a memory to a buffer in a conventional image forming apparatus.

FIG. 6 is a diagram showing an embodiment in which input image data is stored in a memory corresponding to m light beams or m ink ejection units in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 memory 1a, 1b, 1c, 1d Data storage part A1-A4 buffer B1-B4 buffer 11-14 Laser diode L1-L4 Laser beam 15 Polygon mirror 16 Photoconductor drum 17 Main control part

Claims (5)

[Claims] 1. An apparatus for simultaneously generating and scanning a plurality of light beams based on independent image data to form an image on an image forming surface, wherein input image data is input to a plurality of light beam generating means. An image forming apparatus, wherein a plurality of divided image data are simultaneously read out from the storage unit when the image data is output and provided to a corresponding light beam generating unit when the image data is output. 2. The method according to claim 1, wherein the number of light beams is m, and m data storage units corresponding to the m light beams are provided in the storage means, and s, m + s, 2m + s,. 2. The data of the main scanning direction line is stored in the form of (1).
An image forming apparatus according to claim 1. 3. The light beam generating means is a laser diode, the light beam is a laser beam, the image forming surface is a photoreceptor surface, and an image formed on the image forming surface is an electric latent image. The image forming apparatus according to claim 1, wherein: 4. An image forming apparatus for forming an image on a sheet by simultaneously discharging ink from a plurality of ink discharge units based on independent image formation data, wherein the input image data corresponds to the plurality of ink discharge units. An image forming apparatus, wherein a plurality of divided image data are simultaneously read out from the storage means at the time of outputting image data and given to the corresponding ink ejection means. 5. The method according to claim 1, wherein the number of the ink ejection means is m, and the corresponding m data storage sections are provided in the storage means, and s, m + s, 2m + s,. 5. The data of the main scanning direction line is stored in the form of ..
An image forming apparatus according to claim 1.