JPS62146067A - Modulation signal distribution device - Google Patents

Abstract

PURPOSE:To simplify a control circuit, and to eliminate the need for a picture memory of one page by preparing a double number of memories which store a data of one scanning line as the number of beams, allocating two memories for each beam, and using one memory for a read while another memory is used for a write. CONSTITUTION:Each of a picture signal write clock CLK, a line synchronizing signal SLS, and a picture signal read clock CLKR is outputted in a regulated cycle. The picture signals are written in order at line buffers 31-34 from a slight register 30 synchronizing with the SLS as a data (a), a data (b), a data (c)..., and each datum is outputted from the line buffers 31-34 to shift registers 37 or 38 synchronizing with the clock CLKR. A pair of line buffers connected to each of the shift registers 37 and 38 are put in a write enable state or a read enable state with a chip selector 35, and the data is read only from the line buffer put in the read enable state.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for transmitting serial image signals from a data line etc. to a multi-beam laser printer without using a complicated control circuit or an image memory for one page. The present invention relates to a modulated signal distribution device capable of converting into a modulated signal.

[Conventional technology]

As a conventional modulated signal distribution device, for example, there is one shown in FIG. 3, which includes a line synchronization signal generation section 20 that generates a line synchronization signal every time a line changes, and an image signal that is sent to a semiconductor laser driver and an image memory 22. An image signal clock generation section 21 that generates a synchronization clock for the image processing, and a memory group 221, 222, 223 that stores one line of image data...22. an image memory 22 that stores image data for one page;
Shift registers 23 and 24 that store the data read out from the image memory 22; a semiconductor laser drive 25 that drives the semiconductor laser l based on the data output from the shift register 23; and data output from the shift register 24. It is composed of a semiconductor laser driver 26 that drives the semiconductor laser driver 2 based on the following. Note that the shift register is provided with two circuits, but this is made to match the number of beams of the laser scanning device to which the modulated signal distribution device is applied, and when there are three beams, the number of circuits is A register is required.

FIG. 5 shows an example of a multi-beam laser printer to which the device shown in FIG.
Semiconductor lasers 1 and 2 modulated and driven by lasers 5 and 26, collimator lenses 3 and 4 that convert the beams from the respective lasers into parallel beams, and collimated lights from the collimator lenses 3 and 4 to be placed on the same optical axis. A beam splinter 5, a cylinder lens 6 that compresses and corrects the angle of inclination of the beam, a polygon mirror 7 that receives the beam from the cylinder lens 6 on one of its mirror surfaces and reflects it in a predetermined direction according to its rotation, and the polygon An f-theta lens 8 corrects the scanning speed of the laser beam from the mirror 7, a cylinder lens 9 compresses and corrects the inclination angle of the laser beam from the f-theta lens 8, and the beam from the cylinder lens 9 sequentially moves the laser beam 2 in the longitudinal direction. It is composed of a photosensitive drum 10 that simultaneously exposes lines and rotates at a predetermined timing to perform sub-scanning.

The operation of the above configuration will be described in detail based on the timing chart of FIG. 6 and the beam deflection diagram of FIG. 7.

The image data is stored in the line memory group 22° of the image memory 22.
22. ．． are stored line by line. In synchronization with the line synchronization signal output from the line synchronization signal generation section 20, the shift register 23 moves to the line memory group 221.
．． After sequentially storing the image data of odd lines as shown in 223.22s, the image signal clock generator 2
The signal is sent to the semiconductor laser driver 25 in synchronization with the clock output from the device 1. Similarly, the shift register 24 sequentially stores image data of even lines like the memory groups 22□, 224, . It is sent to the driver 26. That is, line memory group 22.
data is sent to the semiconductor laser driver 25 via the register 23 to modulate the semiconductor laser driver 1, and at the same time, data in the line memory group 22□ is sent to the semiconductor laser driver 26 via the register 24 to modulate the semiconductor laser 2. Modulate.

In this way, two lines of data are simultaneously read out to the shift registers 23 and 24 (FIG. 6), and the semiconductor lasers 1 and 2 are driven simultaneously.

The two laser beams generated by the semiconductor lasers 1 and 2 enter the beam splitter 5 through the collimator lenses 3 and 4, and the beam splitter 5 is aligned in the horizontal direction and shifted in the vertical direction. (FIG. 7).

The two laser beams exiting the beam splitter 5 reach the polygon mirror 7, and each laser beam is deflected and scanned. Each deflected and scanned laser beam is corrected by an rθ lens 8 and a cylinder lens 9, and then main scans (11) on the surface of the photoreceptor drum 10, simultaneously forming two lines of exposure in the longitudinal direction of the drum. At the same time as the main scanning 11 ends, the photosensitive drum 10 is rotated by a drive mechanism (not shown), that is, sub-scanning (12) is performed. Then,
The image data of the third line and the fourth line are read out to the shift registers 23 and 24, and the above-described process is repeated.

By creating multiple beams as described above, the polygon rotation speed and video rate are 1/1 for the number of beams n.
It becomes n. Therefore, in the above example, it becomes 2. In the case of a single-beam laser printer, in order to increase the speed, it is necessary to increase the rotation speed of the polygon mirror and the modulation speed of the beam by the image signal, and to achieve this, the motor that drives the polygon mirror must be It is necessary to increase the electric power, which causes problems such as noise, heat generation, and shortened lifespan. On the other hand, by creating a multi-beam system, the disadvantages of a single beam can be overcome.

[Problem that the invention seeks to solve]

However, in the conventional modulation signal distribution device, the control circuit for driving the plurality of semiconductor laser drivers alternately or sequentially is complicated, and the image memory for one page is required. .

[Means for solving problems]

The present invention has been made in view of the above, and in order to perform multi-beam modulation control with a simple configuration and without requiring image memory for one page, data for one scanning line is used. The present invention provides a modulated signal distribution device that has twice the number of memory memories as the number of beams, allocates two memories to each beam, and uses one memory for writing and the other for reading.

[Effect]

According to the modulated signal distribution device of the present invention, serial image data is written to one of the tm line memories provided for each beam, and the written data is read out in parallel with the written data of other beams. This simplifies the control circuit and eliminates the need for one page of image memory.

〔Example〕

Hereinafter, the modulated signal distribution device according to the present invention will be explained in detail.

FIG. 1 shows an embodiment of the present invention, and the same reference numerals are used for the same parts as in FIG. 4, so redundant explanation will be omitted. A shift register 30 that sequentially outputs data and an image write signal clock CL when chip selection is performed.
Line buffers 31, 32, 33 and 34 into which image data is written in synchronization with K, and a chip select signal (W/R) for operating each of the line memories 731 to 34 based on the line synchronization signal StS. A chip selector 35 that generates a signal, a signal doubling circuit 36 that outputs a signal with the cycle of the line synchronization signal SLS doubled, and a signal doubling circuit 36 that outputs a signal with the cycle of the line synchronization signal SLS doubled, and a signal doubling circuit 36 that outputs a signal with the cycle of the line synchronization signal SLS, and the data read out from the line buffer 31 or 33 in synchronization with the image signal successive clock CLKR. A shift register 37 sends data to the semiconductor laser driver 25 in accordance with a synchronization signal output from a signal doubling circuit 36, and a shift register 37 stores data read out from line buffers 32 and 34 in synchronization with a clock CLK*. , a shift register 38 that sends data to the semiconductor laser driver 26 in accordance with the synchronization signal output from the signal doubling circuit 36.
It is configured by providing each of the following.

The operation of the above configuration will be explained with reference to the time chart of FIG. Image signal writing clock CL
Kw, line synchronization signal SL, and image signal readout clock CLKM are each output at regular intervals. The image signal is written from the shift register 30 to the line buffers 31 to 34 in order as data ■, data ■, data ■, etc. in synchronization with St and S, and the clock CLK
Each data is output from line buffers 31 to 34 to shift register 37 or 38 in synchronization with R. A pair of line buffers connected to each of the shift registers 37 and 38 are set to a write-enabled or read-enabled state by the chip selector 35, and data is read only from the read-enabled line buffers.

Here, the operation of each part will be explained divided into time intervals (i) to (V).

(a) Section (i) In the digital real image data, data ■ is sent by the shift register 30 to the line buffer 31 as data ■. At this time, the line buffer 31 is write-enabled by the chip selector 35, and data is written to the line buffer 31 in accordance with the clock CLKw. At this time, the line buffer 32 is also write enabled (written after writing to the line buffer 31 is completed), and the line buffer 32
and 34 are in read enable. Therefore, only the line buffers 33 and 34 can read data, and each output data is sent to the semiconductor laser driver 37.
．． 38. This read timing is CI, K
.

determined by The frequency f1 of CLKR is (,=
It is given as 0.5X (frequency f-H of CLKW).

(II) Section (ii) The digital real image data is sent by the shift register 30 to the line buffer 32 as data ■. At this time, line buffers 31 and 32
is write-enabled, and line buffers 33 and 34 are read-enabled. Therefore, the output data of the line buffer 33 is output to the shift register 37, and the output data of the line buffer 34 is output to the shift register 38.

(c) Section (iii) The digital real image data is sent by the shift register 30 to the line buffer 33 as data (2). At this time, line buffers 31 and 32
is read-enabled, and line buffers 33 and 34 are write-enabled.

Therefore, the output data of the line buffer 31 is output to the shift register 37, and the output data of the line buffer 32 is output to the shift register 38.

(d) Section (iv) The digital real image data is sent by the shift register 30 to the line buffer 34 as data (2). At this time, line buffers 31 and 32 are read enabled, and line buffers 33 and 34 are read enabled.
is write enabled. Therefore, each output data of the line buffers 31 and 32 is transferred to the shift register 37.
and on each of the three days.

(v) Section (v): Same as in (i), serial image data from the shift register 30 is written to the line buffers 31 and 32, and data is transferred from the line buffers 33 and 34 in the read enable state. is output to shift registers 37 and 38. Thereafter, the same process as described above is repeated.

As is clear from Fig. 2, according to the apparatus shown in Fig. 1, two parallel image signals with a frequency of % (because CLK* is set to 4 (7) 0.5 times CLK) (during this parallel output, data is serially written to the remaining line buffers).

FIG. 3 shows another embodiment of the present invention. The same parts as in FIG. While it was applied to multi-beam laser printers,
This embodiment is directed to a multi-beam laser printer using three beams. To this end, this embodiment includes a driver 40 for driving the third semiconductor laser 13, a shift register 41 for supplying data to the driver 40, and a shift register 30 that is added in response to an increase in the number of beams. Line buffers 42 and 43 for writing and reading serial image data output from
Constructed in addition to the illustrated embodiment.

The connections between line buffers 31 to 34 and 42.43 and shift register 37.38 and old are as follows: line buffers 31 and 34 for shift register 37, line buffers 32 and 42 for shift register 38, and line buffers 32 and 42 for shift register 41. On the other hand, it is a combination of line buffers 33 and 43.

In the above configuration, line buffers 31, 32 and 3
Writing and reading processing is performed separately into a group of 3 and a group of line buffers 34, 42 and 43,
When one group is in write enable state, the other group is in read enable state.

To explain it in accordance with FIG. 2, sections (1) and (ii
), the data ■ to ■ are sequentially written to the line buffers 31 to 33 via the shift register, and the data in the section (iii
) and (iv), data ■ to ■ are read out from line buffers 31 to 33 and transferred to shift registers 37 and 38.
．． 41. During this parallel data read time, the serial image data (data ■ to ■) is transferred to the line buffers 34, 42, 4 via the shift register 30.
3 each. Therefore, the clock CL K R in the embodiment of FIG. 3 is set to f8~'o/3.

Above, the cases where the number of beams is 2 and 3 have been illustrated, but even if the number of beams increases further, the line buffer is multiplied by 2N for the number of beams N, and the data from the line buffer is transferred. The present invention can be applied by simply increasing the number of registers by N times.

〔Effect of the invention〕

As explained above, according to the modulation A3 distribution device of the present invention, two memories are provided for each beam to store data for one scanning line, and when one is being read, data is written to the other. Since reading and writing can be performed simultaneously, the control circuit can be simplified, and there is no need to use an image memory for one page, making real-time processing possible. Moreover, it is possible to reduce the cost of the system.

Furthermore, since serial image data can be written in real time, connection with general lines is possible.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a time chart showing the operation of each part of the embodiment of FIG. 1, and FIG. 3 is a block diagram showing another embodiment of the present invention. FIG. 4 is a block diagram showing an example of a conventional modulated signal distribution device, and FIG.
The figure is a configuration diagram of an optical system showing an example of a multi-beam laser printer to which a modulated signal distribution device is applied, FIG. 6 is a time chart showing the operation of the device of FIG. 4, and FIG. 7 is a diagram of the printer of FIG. Optical path explanatory diagram. Explanation of symbols 1.2.13... Semiconductor laser, 20... Line synchronization signal generation section, 25, 26.4
0...Semiconductor laser driver, 30...Shift register, 31-34.42.43...Line buffer, 35...
...Chip selector, 36...Signal doubling circuit, 37, 38.41...Shift register. Patent applicant Fuji Xerox Co., Ltd. Agent Patent attorney Shin Matsuhara 2 Same person Seiji Muraki Same person Same person Jun Ueshima - Same person Hiroaki Sakai? 1 Figure 5 Q Figure 6 41m4L No. 70y7
-------J]'=shirtrt-No. 70

Claims (2)

[Claims] (1) In a multi-beam laser scanning device that simultaneously generates multiple laser beams with different modulation contents to simultaneously form multiple scanning lines on a sensitive material surface, one of the image data for modulating the laser beam. Each beam has two memories that temporarily store scanning line segments.
A modulated signal distribution device characterized in that when one memory writes, the other memory is used for reading. (2) A control means is provided for sequentially writing to the memory to be written in in units of one scan, and for simultaneously reading from all of the memories to be read from the memory. A modulated signal distribution device according to claim 1.