JPH0773322B2 - Image information supply device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an image information supply device that supplies image information to an image output device.

[Conventional technology]

FIG. 3 is a perspective view of a laser beam printer showing an example of this type of apparatus. Reference numeral 21 is a laser oscillator, 22 is a reflection mirror, and a laser beam emitted from the laser oscillator 21 is guided to a modulator 23. A beam expander 24 expands the beam diameter of the parallel light. Reference numeral 25 is a motor such as a synchronous motor, which rotates the polyhedral rotating mirror 26 at a constant speed. 27 is f ・ θ
The imaging lens having the characteristics sweeps the laser beam LB scanned by the polygon mirror 26 in parallel and uniformly forms an image on the photosensitive drum 28. 29 is a charger, which uniformly charges the photosensitive drum 28. Reference numeral 30 denotes a developing device, which wets the latent image formed on the photosensitive drum 28 with a developing material such as toner. A transfer charger 31 transfers the visualized toner image onto the recording paper 32. 33 is a cleaner section for collecting the remaining developer.
A beam detector 34 is composed of a photoelectric conversion element having a fast response time, such as a PIN diode, detects the position of the laser beam LB to be swept, and outputs a detection signal E2 (described later). Reference numeral 35 denotes a drum rotation position detector, which is composed of, for example, a well-known Hall element utilizing the Hall effect,
When the magnet 36a mounted on the disk 36 mounted coaxially with the 28 passes the drum rotation position detector 35 in response to the rotation of the photosensitive drum 28, the rotation of the photosensitive drum 28 is caused by the Hall effect. Detect the position. By this detection signal E1 (described later), the start of the drum rotation direction and recording paper
Determine the transport start timing of 32. Paper feed rollers 37 and 38 feed the recording paper 32. Note that the modulator 23 uses an acousto-optic device that utilizes a known acoustic effect.

Conventionally, this type of device is configured as described above, and image information sent from a host computer or the like that is an external device, that is, character codes, print control data, etc., is once edited for each page for several pages. And store it in the page memory. The image information for one page stored in the page memory is sequentially read and converted into dot data according to the character code. Then, according to the converted dot data, for example, in the laser beam printer, the laser beam
The latent image is formed on the photosensitive drum 28 by controlling the modulation of LB into an on / off signal according to the dot data. Subsequently, the formed latent image is developed with a developer such as toner, the toner image transferred to the conveyed recording medium, for example, the recording paper 32 is transferred, and the toner image transferred to the recording paper 32 is heated. The desired image is obtained by fixing and outputting.

Such printers are available in various print densities according to the intended use.

There is DPI (dot per inch) as a unit for expressing the printing density of the printer, and it is customary to express it by the number of printing dots per inch. For example, if the print density is 240 DPI, printing is performed with a density of 240 dots per inch.

[Problems to be solved by the invention]

However, the recording density of the printer is minute according to the purpose of the user, that is, the accuracy is required such as drawings and circuit diagrams, and the recording density is not required so much.
For example, it is used for general document output. The former has a recording density of 400,480 DPI, and the latter generally has a recording density of 240 DPI.

Also, in the US and Europe for general document output
A 300DPI printer is used and 240D for Kanji output.
A PI printer is being used.

However, the recording density of the printer is set at the time of shipment of the printer, and each printer can print only the unique recording density that is set, and in particular, the one with the recording density of 480 DPI can be used for Kanji output. However, there is a problem that the user has to purchase a printer for kanji output, which is extremely uneconomical.

Conventionally, a device for supplying image information to a printer uses an oscillator provided with a frequency corresponding to the recording density of the printer as an oscillator for generating a carrier clock for carrying the image information, or an oscillator using a changeover switch. It was something to choose.

However, the former requires a dedicated image information supply device individually according to the recording density of the printer, which makes management difficult.
The latter has a problem that the setting of the changeover switch has to be done one by one at the time of factory shipment, which causes a cost increase.

The present invention has been made to solve the above-mentioned problems, and eliminates the troublesome adjustment of the carrier frequency at the time of factory shipment with a simple configuration, and improves the versatility of the image supply device, thereby improving the market. An object of the present invention is to obtain an image information supply device that can be easily maintained in a computer.

[Means for solving problems]

The image information supply apparatus according to the present invention is the image information supply apparatus connected to an image output apparatus having a scanning unit that scans modulated light modulated according to image information at different scanning speeds according to recording density, Input means for inputting a sync signal output from the image output device for each scanning of the modulated light, monitoring means for monitoring the frequency of the sync signal input by the input means, and an output means for monitoring the frequency of the sync signal. Selection means for selecting the carrier frequency of the image information to be output to the image output device.

[Action]

According to the present invention, the carrier frequency of the image information to be supplied to the image output device is selected in accordance with the frequency of the synchronizing signal monitored by the monitoring means, and the carrier frequency is selected according to the recording density in the image output device connected with a simple structure. The optimum carrier frequency of image information is automatically selected.

〔Example〕

FIG. 1 is a block diagram showing the configuration of an image information supply device showing an embodiment of the present invention. Regarding the structure,
Description will be made with reference to FIG.

In this figure, reference numeral 1 is an input control unit that interfaces text information A consisting of character codes, which is communicated from the host computer. Reference numeral 2 denotes a page memory in which the previously stored text information A is sequentially erased by the text information A input to the input control unit 1. A main control unit 3 refers to the character pattern generation unit 4 to convert the character code read out from the page memory 2 into dot pattern information B for each character and store it in the scan buffer 5. The scan buffer 5 is composed of a first scan buffer 5a, a second scan buffer 5b, and the like, and can alternately read and write in parallel. The main controller 3 also sends to the selector 10 a clock selection signal J for selecting the carrier frequency of the dot pattern information B constructed in the scan buffer 5 according to the input pulse signal F2. A read control unit 6 is a read signal C sent from the main control unit 3.
The dot pattern information B is alternately read from the first scan buffer 5a or the second scan buffer 5b in accordance with the above. A parallel-serial converter 7 converts the dot pattern data D read by the read control unit 6 and sends it to an image forming unit (not shown). Reference numeral 8 denotes a flip-flop (hereinafter, referred to as FF), which is set by the detection signal E1 output from the drum rotation position detector 35 and sends a pulse signal F2 to the main control unit 3. Reference numeral 9 is a counter, which is output from the beam detector 34. Counts the detection signal E2 and counts the counter data CD
Is sent to the main control unit 3. 10 is a selector, which is the main control unit 3
The clock generators 11a to 11b are selected according to the clock selection signal J sent from the CPU. The selector 10 outputs the selected carrier frequency signal K to the parallel-serial converter 7.

The FF8 is reset by the reset signal G sent from the main control unit 3. H is a drum rotation signal, which the main controller 3 sends to a drive system (not shown) that drives the photosensitive drum 28. I is a conveyance start signal, and the main controller 3 causes the paper feed rollers 37, 3
8 is sent to a drive system (not shown) that drives 8. F2 is FF8
The pulse signal is output according to the detection signal E1 input to the OR circuit OR and the main control unit 3. F1 is a pulse signal output from the main control unit 3 and is output to the OR circuit OR, and the OR output F3 sets the counter 9.

Next, the operation will be described.

The text information A composed of character codes sent from a host computer serving as an external device or a magnetic tape device is temporarily stored in the page memory 2 by the input control unit 1 and stored in the page memory 2 by the main control unit 3. The written text information A is read in order from the beginning. At the beginning of the text information A, a control code for designating the recording density of the printer is entered as a control code from the host computer.

The main controller 3 outputs a pulse signal F1 to the counter 9 before writing an image. As a result, the counter 9 counts the frequency of the detection signal E2 output from the beam detector 34 for a predetermined time and outputs the counter data CD to the main controller 3.
The main control unit 3 monitors the count data CD, and when the change state thereof, for example, the recording density changes from 240 DPI to 300 DPI, the frequency of the detection signal E2 input to the counter 9 is 300 /
Since it becomes 240 times, if the count data CD at 240 DPI is 24, the count data CD will be 30 at 300 DPI. Therefore, a clock selection signal J for selecting the carrier frequency of the dot pattern data D is set in the selector 10 according to the change of the count data CD, and the clock generator 11 is set.
A selector 10 selects an appropriate clock from a to 11d, and a carrier frequency signal K for carrying the dot pattern data D is sent to the read control unit 6 and the parallel-serial converter 7. Next, the main control unit 3 converts the character code read from the page memory 2 into character dot pattern information B by referring to the character pattern generation unit 4, and by repeating this for one line, the character dot pattern information B Among them, the information for one scanning line is stored in the scan buffer 5. When the dot pattern information is stored in the scan buffer 5,
Since the main controller 3 outputs the drum rotation signal H to the printing unit (not shown), the photosensitive drum 28 starts to rotate and the magnet 36a mounted on the disc 36 causes the drum rotation position detector 35.
When it passes, the detection signal E1 is output and EE8 is set, so that the OR output F3 becomes HIGH. Since the pulse signal F1 is at the LOW level in the printing state, at this point the counter 9
Is cleared, the counter 9 sets the beam detector 34
The count of the detection signal E2 from is started. Pulse signal F2
Is sent to the OR circuit OR and is also sent to the main control unit 3, so that the read signal C is output to the read control unit 6 and the dot pattern from the scan buffer 5 is synchronized with the carrier frequency signal K. The reading of the information B is started. The dot pattern information B read by this is converted into serial data by the parallel-serial converter 7 in the subsequent stage in synchronization with the carrier frequency signal K, and then sent out to a printing unit (not shown) so that it is projected onto the photosensitive drum 28. It is irradiated as information. The main control unit 3 senses the value of the counter 9 and counts the value at which the photosensitive drum 28 rotates and reaches the position where the leading edge of the text information irradiated on the photosensitive drum 28 and the leading edge of the recording paper 32 coincide. When the value reaches, the conveyance start signal H is output, the paper feed rollers 37 and 38 rotate in synchronization with the conveyance start signal H, and after 221 sheets of recording paper have been conveyed, stop.

When the main controller 3 has finished writing the dot pattern information B for one page, it stops the write operation to the scan buffer 5, drops the read signal C and outputs the reset signal G, so that FF8 is cleared. Along with this, the counter 9 is also cleared. When the read signal C drops, the read control unit 6 stops the read operation at the time point when the dot pattern information B for one scanning line currently being read has been read, so that the irradiation of the text information on the photosensitive drum 28 ends. . The photosensitive drum 28 continues to rotate after this and continues to rotate.
When the magnet 36a on the 36 reaches the position of the drum rotation position detector 35, the detection signal E1 is output and the printing operation of the next page is started to set FF8.

2 (a) to (c) are schematic diagrams showing an example of print output according to the present invention, and FIG. 2 (a) shows enlarged characters when output is performed at a recording density fixed to the apparatus. b) shows enlarged print characters (for example, A) when the rotation speed of the motor 25 is increased without changing the rotation speed of the photosensitive drum 28, that is, when the scanning frequency is increased, and FIG. The enlarged print characters are shown when the number of rotations of 25 is increased and the carrier frequency signal K of the dot pattern information B is increased.

As can be seen from this figure, when the number of rotations of the motor 25 is increased without changing the number of rotations of the photosensitive drum 28, the recording density in the recording paper conveyance direction (arrow direction) increases, as shown in FIG. 2B. Since the characters to be printed become smaller in the vertical direction, in the present invention, by increasing the carrier frequency of the dot pattern information B and increasing the rotation speed of the motor 25, normal characters (certain fixed characters Characters with higher density than the output characters of recording density (shown in (a) of the same figure) ((c) of the same figure)
Reference) can be output. Incidentally, the rotation speed of the photosensitive drum 28 is usually not changed due to the stability of the printing paper conveyance system and the delicate potential holding characteristic of the photosensitive drum 28.

In the above embodiment, the case where one type of carrier frequency is selected from the clock generators 11a to 11b has been described, but the type of clock generator that can be selected by increasing the number of bits of the clock selection signal J, for example. Can be increased.

Needless to say, when the control command for designating the recording density from the host computer as an external device is not applied to the text information A, the image is output at a fixed recording density.

Further, in the above embodiment, the recording density changing operation in the laser beam printer has been described, but the present invention can be applied to an inkjet printer and the like. In this case, the same effect can be obtained by changing the feeding speed of the scanning drive system in the main scanning direction and the carrier frequency of the constructed image information.

In addition, the count data CD of the counter 9 is the clock generator.
If the values are far from the values used when selecting the frequencies 11a to 11d, the error can be detected and displayed as a scanner error.

〔The invention's effect〕

As described above, according to the present invention, means for inputting the synchronizing signal output from the image output device for each scanning of the modulated light, and monitoring for monitoring the frequency of the synchronizing signal input by the input means Since the means and the selecting means for selecting the carrier frequency of the image information to be output to the image output apparatus according to the output of the monitoring means are provided, the recording density in the image output apparatus connected with a simple structure can be improved. Since the carrier frequency of the image information according to it can be automatically selected, the troublesome adjustment of the carrier frequency at the time of factory shipment is eliminated, and the versatility of the image supply device is improved, so that it can be maintained in the market. Has the effect of being simplified.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an image information supply apparatus showing an embodiment of the present invention, FIGS. 2 (a) to (c) are schematic diagrams showing an example of print output according to the present invention, and FIG. It is a perspective view of a laser beam printer which shows an example of a device of a kind. In the figure, 1 is an input control unit, 2 is a page memory, 3 is a main control unit, 4 is a character pattern generation unit, 5 is a scan buffer,
6 is a read control unit, 7 is a parallel-serial converter, 8 is FF,
Reference numeral 9 is a counter, 10 is a selector, and 11a to 11d are clock generators.

Claims (1)

[Claims] 1. An image information supply device connected to an image output device having scanning means for scanning modulated light modulated according to image information at different scanning speeds according to recording density, wherein: Input means for inputting a synchronization signal output for each scan of the modulated light, monitoring means for monitoring the frequency of the synchronization signal input by the input means, and the image output device according to the output of the monitoring means. An image information supply device, comprising: a selection unit that selects a carrier frequency of the image information to be output to the image information supply device.