JPS60234389A - Laser light modulator circuit - Google Patents

Abstract

PURPOSE:To decrease the loss of power of an electric current driving measure for modulation, and improve the response, by a method wherein when the modulation of laser light is carried out, the electric current driving measure which flows the electric current to a semiconductor laser under threshold value electric current generating light oscillation is always driven as well as the electric current driving measure which is connected with this in parallel is ON/OFF controlled. CONSTITUTION:The first electric current driving measure 257 which flows the electric current under the threshold value, in which a semiconductor laser 259 generates light oscillation, to the semiconductor laser 259, and the second electric current driving measure 258 connected to the electric current driving measure 257 in parallel, are provided, and when the modulation of the laser light is carried out, the first electric current driving measure 257 is always driven as well as the second electric current driving measure 258 is made ON/OFF controlled. Hereby, sufficient modulation operation can be carried out even if small electric power transistor is used for the second electric current driving measure 258. Furthermore, since it is possible to make small the driving current of the second electric driving measure, the responsibility can be improved than in the case the modulation is carried out by one transistor, and also the control of minute light output will be possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention 1] The present invention relates to a laser light modulation circuit that controls and modulates a current supplied to a semiconductor laser.

[Technical Background of the Invention and its Problems] Conventionally, modulation transistors have been used to modulate semiconductor lasers. Usually, the modulation frequency of this modulation transistor is about 4 to 10 MHz, and fast response is required. Therefore, modulation transistors are used for high frequencies. However, high-frequency transistors suffer from power loss due to their junction capacitance.
The drawback was that large current transistors had to be placed in order to compensate for this power loss.

UObject of the Invention 1 The present invention has been made in view of the above-mentioned circumstances, and aims to reduce the loss power of the current drive means for modulation, improve the responsiveness of the current drive means, and perform minute modulation control. The object of the present invention is to provide a laser light modulation circuit that can perform the following steps.

[Summary of the Invention 1] The outline of the present invention for achieving the above object is to provide a laser light modulation circuit that modulates laser light by controlling the current supplied to a semiconductor laser, in which a current equal to or less than the equivalent current at which the semiconductor laser causes optical oscillation is used. The first step is to pass a current of
and a second current driving means connected in parallel with the first current driving means, and when modulating the laser light, the first current driving means is constantly driven and the second current driving means is connected in parallel with the first current driving means. , is characterized in that the second current driving means is controlled in a 0N10FF manner.

In the following margin [Embodiment 1 of the Invention] Hereinafter, a description will be given with reference to an illustrated embodiment to which a water valve and light are applied.

FIG. 1 is a block diagram of a system for recording information on a recording medium by means of a sea beam. Information from a host system 1 (electronic computer, word processor main body, etc.) that supplies information is given to a data control unit 2. The data control unit 2 converts the information given from the host system 1 into data corresponding to dots and stores it in the page memory.

This stored dot image data is transferred to the print control unit 10.
Send to 0.

The print control section 100r writes the input dot image data onto a recording medium by modulating a laser beam, develops and transfers it, and prints the dot image data on a recording sheet.

FIG. 2 shows a detailed view of the line grooves of a printer 300 having a video interface, and the printer 300 incorporates the printing control section 100 shown in FIG. 1.

In FIG. 2, 300 is the printer body, 301 is
photoreceptor for recording information by laser beam,
Reference numeral 302 denotes a static elimination lamp for eliminating the charge on the photoreceptor 301 to its initial state. It is composed of 12 red LEDs. Numeral 303 is a static elimination lamp for increasing transfer efficiency, and like the static elimination lamp 302, it is composed of a plurality of red LEDs.

304 is a charging charger for uniformly charging the photoreceptor 301 to a predetermined potential; 305 is the photoreceptor 301;
A transfer chiller 306 is for transferring the developed toner onto the paper, and a peeling charger 306 is for separating the paper after transfer from the photoreceptor.

307 is a second developer for developing an electrostatic latent image written on the photoreceptor 301 by the C+1- beam; 308 is a component of the developer 307, which transfers the toner to the photoreceptor; This is a magnetic roller for attaching the electrostatic latent image on the body 301, and rotates in the direction of the arrow.

309 is a toner probe 71 that comes into contact with the developer of the magnetic roller and measures the edge-specific density of the developer; 310 removes the toner remaining on the photoreceptor 301 after transfer; This is a cleaning blade for.

311 is the video data input from the data control unit,
312 to a laser scanner for scanning, modulating, and recording a laser beam on the photoreceptor 301;
31 is an octahedral polygon mirror for guiding a laser beam from a laser diode onto the photoreceptor 301;
3 is a ski II motor for rotating the polygon mirror 312 at high speed, and 314 is an f/θ motor for keeping the scanning speed of the laser beam on the photoreceptor 301 constant.
It's a lens. 315 and 316 are reflecting mirrors for guiding the laser beam from the scanner unit 311 to the photoreceptor 301.

317 is an upper cassette that can hold 500 sheets of paper.
378 is an upper paper feed roller for not taking out sheets one by one from the upper cassette 317; 319 is an upper paper out switch for detecting that there is no paper in the upper cassette 317; and 320 is the "two-stage" switch. A noise detection switch is installed in the cassette 317 (a 1L cassette consisting of 4 pits that detect marks for identifying the cassette). 321 is a lower paper feed roller, and 323 is a lower paper out switch. , 324 indicate the lower tier pressure plate 1-receive detection switches, respectively.Furthermore, the upper tier side has a structure in which 250 sheets can be stored and the curry 1~ on the lower tier side can also be used.

325 is a manual feed switch for detecting paper inserted from the manual feed guide 326; 327 is the manual feed switch for detecting paper inserted from the manual feed guide 326;
A manual paper feed roller 32 for transporting the paper after the insertion is confirmed by the alpha feed switch 325;
Reference numeral 8 denotes a switch to the manicoars 1, which detects the paper conveyed by the manual paper feed roller 327.

Reference numeral 329 denotes lenses 1 to 21-ra for synchronizing the image developed on the photoreceptor 3011- with the paper.

330 is a conveyor belt for generally transporting the paper separated by the peeling charger 306 to the joseki;
31 is a fixing device for fixing the image on the rolled paper; 332 is a fixing roller; 333 is a heater lamp for heating the fixing roller; 334 is a surface of the fixed roller; Glue mister for detecting temperature, 3
35 is a paper discharge roller; 336 is a ↑)1 paper switch for detecting the paper discharged from the fixing device 331;
.

337 is a cooling fan for cooling the inside of the printer 300, and 338 is a cooling fan that rotates the charging controller 304 degrees. f
-f-t+-17305 A high voltage transformer that generates high voltages to be applied to the peeling derager 306, the developing device, and the magnet roller 308, respectively.

339 generates DC voltage used for each control 11
- The power supply unit fFff, 340 controls the printer 300.
There is one PC board per unit.

342 is installed near the photoreceptor 301 (the photoreceptor 30
A thermistor with very low thermal resistance is used to detect the drum temperature.

FIG. 3 is a perspective view showing an outline of the first part where information is recorded on the photosensitive element f* 301 by a laser beam. In FIG. 3, 1 emitted from the semiconductor laser 344
The norther beam is corrected into parallel light by the collimator lens 343, and the parallel light is passed through the polygon mirror 31.
-C is applied to one side of the 3 octahedron. Since the polygon mirror 313 is rotated at high speed in the direction of the -C1 arrow by the scan motor 312, the laser beam incident on the polygon mirror passes through the f/θ lens 314,
The beam scanning range 348 is scanned from left to right. A portion of the laser beam within the beam scanning range 348 is guided by a reflecting mirror 345 to a beam detector 346 . Therefore, each time one of the polygon mirrors 313 performs one horizontal scan, the beam detector 34G detects the laser beam being scanned. Further, the laser beam that is not applied to the reflecting mirror 345 within the beam scanning range 348 is irradiated onto the photoreceptor 301 . In Figure 3, the location where the laser beam is scanned on the photoreceptor 301 is 3.
49. 30/I represents a charger, and 347 represents a sheet of paper. As shown in FIG. 2, in an actual printer, the laser beam that has passed through the f/θ lens 314 is not directly irradiated onto the photoreceptor 301, but is reflected by the reflecting mirrors 315 and 31G. C
Although it is guided by the photoreceptor 310, it is conveniently shown in FIG.
- Reflection mirrors 315 and 316 are not shown, and one norther beam that has passed through the f/θ lens 314 is directly directed to the photoreceptor 30.
1 is shown as if it were irradiated.

11th regarding the configuration of the reflecting mirror 345)
．． See the explanation with reference to Figure 2. As shown in the figure, this repulsion mirror 345 is connected to the support member 4 located outside the beam incident area.
56 J is removed by a screw 455 via a leaf spring 454, and a fine adjustment screw 457 is installed in the T portion of this leaf spring 454 (the reflection mirror 371 is removed).
It is equipped so that the angle of 5 can be changed.

As is clear from FIG. 2, the Ray-scanner unit 1 shown in FIGS. 3 and 42 is shielded from the outside to prevent the scanning beam from leaking. The detection result of the beam detection by the beam detector 346 is then placed at an appropriate position on the scanning panel shown in FIG.
'3 is now displayed.

FIG. 4 is an explanatory diagram of the bus sensor in front of the registration roller. Manual stop switch 328 in Figure 2
The register 394 only detects manually fed paper, whereas the register front pass lenser 394 detects paper when paper is fed from a cassette. In FIG. 4, the paper fed from the lower cassette 317 and the lower cassette 321 by either the upper paper feed roller 318 or the lower paper feed roller 322 is fed along the paper guide plate to the registration roller 329. be done. At this time, if paper feeding is performed correctly, the light emitted from the light emitting diode 393 is blocked by the paper, and the light does not enter the registration roller front bus sensor 394, so that the fed paper can be confirmed. Furthermore, if the paper is not fed correctly, the paper will not reach the position of the registration roller front path sensor, and the light from the light emitting diode 393 will continue to be input to the registration roller front path sensor. ,
It can be recognized that the paper is not being fed.

Figure 5 shows the inversion 1-ray 3 to option unit 1.
7, which is a schematic diagram of 81, the printer 300 normally has a second
As shown in the figure, a non-reversing type printer 397 is installed.If such a non-reversing type is used, the first printing paper will be on the bottom side, so Since data must be sent from the last page from the information providing device (bost system 1), the method of filing information in system 1 to host 1 becomes complicated.(,
'Yg, in order to compensate for the drawbacks mentioned above, the book reversing tray 3
81 is essential.

In FIG. 5, the paper that has passed through the paper ejection roller 335 of the printer 300 is transported by transport rollers 382 and 383.
(-The sheet is stored in the tray 384 in an inverted form from when it passes through the sheet discharge roller 335.

Therefore, the printed side of the paper is on the bottom side.C1 The first page is on the bottom side, but if you take out the paper from the tray 384 and turn the printed side of the paper on the front side, the first page will be on the top side and the last page will be on the bottom side. The page is on the lower side, and the above-mentioned drawbacks of the non-reversible tray 397 can be solved. In the figure, 385 is a paper stopper that can be slid according to the length of the printing paper in the conveyance direction. 388 is a paper presser actuator to prevent the paper stored in the tray from floating up, and 395 is a paper presser actuator for making sure that the paper is properly stored in the tray 384.
391 is a light emitting diode for checking the presence or absence of paper in the tray 384; 392 is a tray sensor on the light receiving side; Paper 390 is in tray 384
If the tray sensor 392 is within the tray sensor 392, no light will shine on the tray sensor 392, and if there is no paper 390, the presence or absence of the paper 390 can be detected by shining light on the tray sensor 392.

FIG. 44 shows the other systems of the paper presence/absence and paper full detection units. This causes the actuator 38 to rotate around the pivot point 386.
8 is provided, and a lever 398 is provided in series above,
Cover the tip of the lever (3°C) 8 with the solenoid 389 as the separating means and the coil 387 as the release means and turn it in one direction with a force of ζ1 d3 until the paper is stored in the paper storage section 390. Then, move the lever 398 -U, and detect this state by means of detecting means, for example, Fj number sensors 401, 402.
As detected by 1 no (there is.
In the various states of 88, the position of al is "paper full", a2
The position a3 becomes "1 paper available" and the position a3 becomes "no paper". The separating means 389 separates the actuator 388 at least while the paper 390 is being discharged and moved into the paper discharge 1 to ray 38/lI (or when the actuator 388 should be separated and the paper should be detected, for example, during printing operation or stoppage). The solenoid 389 is turned off in synchronization with the state signal of the actuator 388, and the sensing operation is performed.
8, and the ejection operation is not hindered. .

Note that each sheet of paper sent into the paper ejection tray is detected by the paper ejection switch 395, and the contents are stored in the paper ejection memory counter (RAM 107 in FIG. 13), which will be described later.
C is counted and the number of sheets is detected. When the C11 paper becomes full 1, it is displayed on the tray full lamp 358 in FIG. 6 and the memory counter is cleared.

FIG. 6 is a detailed diagram of the operation panel of printer 300.

In FIG. 6, C1350 is the top cover of the printer 300, 351 is the front cover, 352 is the maintenance cover, and the above-mentioned note 1) is the front cover 351.
is opened in the direction of the arrow when the paper jam, toner replenishment, etc.
2 has a structure that opens at the top, but the front cover 35'1 cannot be heard unless the front cover 35'1 is pointed in the direction of the arrow, to prevent operator's erroneous operation.

353 is a 6-digit mechanical counter, which is incremented by 1 each time a sheet of paper is printed. 354 is a select switch that selects online/offline + 3 <l
J corresponds to the select switch 354 and is a select lamp that lights up when online.

35G is a single digit seven leg LIE D, error details when serviceman yells, maintenance mode,
357 is a power lamp that indicates that the printer 300 is powered on; 358 is the inverted tray unit 38;
Reference numeral 1 indicates a tray full lamp for indicating that the printing paper is full, and reference numeral 359 indicates a color 1cD indicator for displaying details of the printer's @fabric status. 1 explained so far
- Tarkaran 353 to CD display 359 is always operated or displayed. Next, parts that cannot be operated unless the maintenance cover 352 is removed will be explained. The following parts should only be operated by service personnel.
It is written by E.

403 is a maintenance switch for selecting maintenance mode and replacement mode, and 406 is an indicator lamp indicating that maintenance mode is low.

407 is an indicator lamp indicating that it is in exchange mode;
404 indicates each mode a,
a selection switch 408 for making a selection; a selection lamp 408 indicating every four guns that can be selected by the selection switch 404;
405 is a death switch for selecting prints 1 to 7 and performing the above-mentioned maintenance, replacement, and operation in each mode of prints 1 to 1, and 360 is a main exposure switch for The polycomb for adjustment, 361 indicates the polycomb for exposure adjustment, and the above-mentioned 360 and 361 both have a structure in which an adjustment screwdriver is inserted and turned, and the maintenance cover 352 You cannot turn it by hand while listening to it.

FIG. 7 is a detailed diagram of the 1cD display 359, and the function of each display segment will be explained below.

371.372 is a segment indicating the standby, ready state, etc. of the printer 300. When the printer 300 is on standby until the fuser is ready, both 371 and 372 are lit, in the ready state only 371 is lit, and when printing is in progress, 371.3372 is lit. of! X
The lights are off.

373 indicates the paper feeding unit's 1 ＼ signal, which blinks in a single segment to indicate the paper feeding status (- also blinks at the same time).

Rope) 5, hand 7 L modero, blasphemous manual feed designation 365.
When the first stage cassette 1 is entered, the cassettes 1 to 364 flash, and when the lower cullet is displayed, the lower cullet 363 flashes.

374 is a transport system (regist (]-ra 329 and later)
It flashes when the number is 7. In this case, the paper feed segment also blinks at the same time as in the case of a paper feed jam. 375 indicates that the gutter collected by the cleaning blade 310 in FIG.
It blinks when the tank (not shown) is full. 376 blinks when the developer 307 runs out of toner (not shown). , 377
．． 378 blinks when a serviceman error, which will be described later, occurs. 379 blinks when an operator roll, which will be described later, occurs. 380 blinks if there is no paper in the selected cassette. 362 displays the size of the selected set. For example, if the 10-tier cassette side is selected and the A4 vertical paper cassette is selected, Δ4-R lights up, and if 80 is selected in the manual feed mode, 80 lights up. 363 is lit when the lower cassette is selected, 364 is lit when the 11th cassette is selected, and 365 is lit when manual feed is selected. 3
66 represents the shape of the printer 300 and is always lit.
367 represents the photoreceptor 301, which is always lit; 368
369 represents the shape of the upper part of the printer 300, which is always on except when the transport section is jammed, and 369 indicates the transport section jam (37
4 is blinking), the above 368 is lit alternately. Reference numeral 370 indicates five segments that display the conveyance state of the paper, and one segment moves from the right side to the left side while lighting up.

. FIG. 8 is a schematic block diagram of the data control section 2 in FIG. 1. The data control unit 2 converts the character code information and image information sent from the host system 1 into a dot-compatible page memory 20-1- corresponding to the printing area of paper-1- of the printer 300. Make me remember. The stored data on the page memory 20 is sent to the printer 300 for printing.

The data control unit 2 is configured to accept two types of information. One is character code information (JIS
In this case, the character generator 15 generates a character pattern corresponding to the character "-" and stores the dot information of the character pattern on the page memory 20. The other is image information, and in this case, it is already input in the form of dot information, so it is stored in the page memory 20 as is. Hereinafter, an overview of the data control section 2 will be explained with reference to FIG.

Information from the host system 1 is sent to the C interface 50 via the signal line S01, and the information is further stored in the data control section 3.

Signal line S between interface 50 and host system 1
O2 is sent from the host system 1. The data strobe signal and the control signal line SO3 are the low signal and status signal line from the data control unit.

The format of the information sent from the host system 1 is shown in FIGS. 9 and 10. The format example in Figure 9 is the format for character code information, where the character identification code indicating that it is character code information and the set size code indicating the size of paper to be printed are for one page. It is included at the beginning of.

Thereafter, character code data are entered in the order of the first line, second line, . Further, character=1-code data for one line is made up of a code indicating the character size, a character code, and a 1F code indicating the delimitation of one line of data.

Figure 10 shows the format 1 for image information, where the image information is shown and the paper size identification code indicating the size of paper to be printed is placed at the beginning of one page of data. It's in. After that, 1 line.

2 lines... Image data is entered in the order of m lines. Furthermore, since one line of data is specified by the paper size identification data, the data control unit 2 automatically determines the specified data by the U count size. It has become.

The input information from the distributor ``a4'' is processed as follows.The information that has entered the distributor 4 is always input from the distributor 4 to the decoder 5 via the output line S○4.First, In the case of character code information, when the character identification code shown in FIG. The main control unit 6 determines that the input information is character code information, and sends a message to the distributor 4 via the signal line SO6.
A command is given to input the next paper size data into the page-]-dodoparagraph control circuit 7. Therefore, the paper size data is input from the distributor 4 to the page buffer control circuit via the data line SO7. The next 1st line, 2nd line・
...The data up to the n-th row is input from the distributor 4 to the page code buffer 77 via the data line SO8. At this time, the character code data is stored in the memory area on the page code buffer 9 designated by the address counter 8. When the input of character code information for one page into the page code buffer is completed and the END code shown in FIG. 9 is detected by the decoder 5, the main control unit 6. page]-de buffer control circuit 7
END code detection is transmitted to each. When the page buffer control circuit 7 confirms through the signal line SO9 that input of character codes for one page into the page code buffer 1 is completed, data is stored in the page memory 20 in units of dots.

FIG. 11 shows the correspondence between memory spaces on the page memory 20 and sheets. In FIG. 11, broken lines indicate the outside of each sheet. In other words, 25 is the leading edge of the paper (common to all sizes), 2
4 is the left edge of the paper (common to all sizes), 28 is the right edge of △51 size paper, 27 is the right edge of A4 size paper, 26 is A3 size paper
Right edge of size paper, 31 is rear edge of A5 size paper, 30
29 indicates the trailing edge of A4I size paper, and 29 indicates the trailing edge of A3 size paper. 32 is the address AD of the address counter 19 for reading 1 and the address counter 18 for loading.
Indicates the point of R(0,0). Here, ADR(0,0
) means that both the vertical direction address (ΔD RV) and the horizontal direction address (ΔD R+-1> are O'. In other words, the write address counter 18 and the read address counter 18 19 is a vertical address (ADRV>) and a horizontal address (ADRV>) as shown in FIG.
ADRH>, ADRV represents a vertical address (arrow b in FIG. 11), and ADR+1 represents a horizontal address (arrow C in FIG. 11).

43 is A 34j, the last horizontal address of the chair paper (
A3HE), 44 is the horizontal address (A3HE) of A4 size paper
/lt IE), 45 is the horizontal address of A5 size paper (
A5HE). Similarly, 46 is the last vertical address of A3 size paper <A3VE), 47 HaA/l
+M, <(7) l direct address (A4vE), 48 is A
Represents a vertical address (A5VE) of 5 digits. 33 is A size vertical address ADRV-〇, horizontal address A
D RH = A 31-I E point ADR (0
, A3HE), 34 is similarly niL"i(' ADR(0
, A4HE), 35 is ADR(0, A31-IF
3) are shown respectively. In addition, 36 is the point ADR (A3VF) of the vertical at L/s ADRV=' (A3VE) and the horizontal 7 L/s A D RH=0 of the A3 lease.

0) and 37 are ADR (A4VE, 0) in the same way.

38 indicates DR (5VF, O), respectively.

39 is △3 size vertical address ADRV=△3VE,
Horizontal address △D R+-1-A 31-I DR to point E (A3VE, A38E), similarly 40
, △ DR (A4VF, △ 4 1-(E)
, 4 1 +, ADR (△5VE, △5HE) is shown.

The character pattern is stored as a dot image in the page memory 20 having the memory space as described above (this is done as follows.Page code buffer 7' 9 J: 1st line character' noise data) It is read by the page code buffer control circuit 7 via the signal line 310.The character size types in this embodiment are basically two types of fonts: 40 x 40 degrees and 32 x 32 dots.
The control circuit 7 determines the character size based on the read character size code, and sends the determination signal to the page memory control circuit 17 via the signal line S11 and to the character generator 15 via the signal line S1.3. The page memory control circuit '17 controls the line break pitch and the character size change using the character size determination signal, and the character generator 15 changes the character size and rear.

Character codes after the character size data are stored in a line address counter 11 in a line buffer 10 with memory capacity for one line.
is specified and transferred to the Iζ area.

1ij worth of characters] - When the transfer of the driver to the row buffer 10 is completed, the row address counter 11 returns to the initial address (0). First, page memory 2 of the first vertical line of the character font (line 57 in Figure 11)
A jump to 0 is performed.

Here, the line/scan counter 13 has an initial value (0,
-C is set to O), and the value of the write address input 1 counter 18 is ADR (0, 0). The character code data in the line buffer 10 is read out sequentially from the first digit with a constant recycle, and is sequentially latched into the output lug 12 in order to synchronize the line counter 13. The first character code ('T' character in this example) is output lug 1.
2, the output of the character=1-dodo line/scan counter 13 is synthesized by the synthesis circuit 14 and input to the character generator 15 as a character pattern selection code. Here, to explain the configuration of the line 7/scan counter 13, the upper 6 bits 1- are a counter for counting scanning lines, that is, a counter in the vertical direction of a character pattern. goes to 0・3
9 plus, line feed pitch control counts 912 minutes and returns to O'.

The lower three pits 1 are horizontally oriented counters of the character pattern, 40 x 4. For O dot fonts, count O to 4 plus character pitch control to 101.
(This is because the output of the character generator 15 is 8-bit parallel).

Below, the font size is 40X40. The operation will be explained when the horizontal spacing between characters is 8 bits, and the vertical spacing of one character is 8 bits. As mentioned above, when the first character code (“T”) is sent to the output lug 12, that character code and the output of the line/scan counter 13 are combined in the synthesis circuit 14, and the character generator 15 selects a character pattern. The code is input to the character generator 15 as a code. At this time, the value of the line/skilleno counter is (0, O), so 4-Yarakutaji "
The output of the generator 15 is the vertical direction 'O' of the character pattern.
' line, horizontal direction '0' data (8 hits)
is output. The output data of the character generator 15 is latched at -H by the output latch 16 in order to synchronize the loading into the page memory 20, and then sent to the page memory control circuit 17.
The data is written to the page memory 200 address specified by the write address counter 18. In this case, since the value of the write address counter 18 is ↑ as AD, R (0, 0), it is written to the vertical address '0' and the horizontal address '0'. When writing of the 1-byte character pattern is completed, the value of the line/scan counter changes to (0, 1>), and the value of the write address counter 1B also changes to ADR (0, 1>). Therefore, the character generator 15 outputs the data of the character pattern at the ``O'' line in the vertical direction and the ``th line in the horizontal direction'', which is latched by the output latch 16 as described above, and then stored in the page memory 20. It is written to address ADR (01).In this way, when the last data (data at '4'4') in the vertical 'O' line of one character pattern is completed, the line/scan The counter's (direct is (0)
, 5), 8-inclusive address counter 18 is ADR (0, 5)
). The horizontal spacing between characters is 8 dots (1 byte)
Therefore, the output of the character generator 15 is forced to all 0' by the command from the page code buffer control circuit 7, and the AD of the page memory 20 is
0' is written to address R (0, 5), and after the write operation is completed, the row address counter is incremented by 1' and the row buffer 1 is
The next character code from 0 is set in the output latch 12. Also, the line/suki V/n counter is o, o), p
The address counter 18 for + includes t at ADR (0, 6). Therefore, next, the data of the 0'th line in the vertical direction of the character pattern "0" is read/written to the page memory 20. At this time, the address counter 18 for old data is
,6),(0,7),(0,8),(0゜9>,(0,
△) and sequentially go up from 1 to 1, and write the character pattern data of O to the address specified by the write address 7J counter 18 with /v.

Is it the value of write address counter 18 (0° [3)?
, line, / Sunirunno J counter 13 value is (0°5)
Then, 0' is written to the page memory 20 as in the previous book, and after the write operation is completed, the row address counter is incremented by 1', and the next character code is set in the output latch 12 from the row buffer 10. be done.

The IC, line 2/scan counter 13 is (0°0)
, the write address counter 18 becomes ADR (0°C). In this way, the character pattern data of line 0' in the set direction is sequentially written into the page memory 20, and when the L I-' code is output to the output of the -C line buffer 10, 'lF']-de detection signal is output line S1
/l is transmitted to the page code buffer control circuit 7, and the operation of inputting and outputting the character pattern from the -1-Yaractage generator 15 is stopped. After that, the write address counter 18 is sequentially incremented by 1 and forced to 0.
' is written to the page memory 20 and proceed with lυ. Then, if the value of the -1 feed address counter 18 is currently specified as A3 size, the value of ADR (0, A3HF), that is, the first
1 When the 33rd point is reached, the above-mentioned forced 'O' After the write operation, the write address counter 18 becomes ADR (1, O),
The row address counter 11.18 (0) and the line/scan counter 13 are set to (1, O), respectively. Then, T', which is the character code of the first character in the line buffer 10, is set in the output latch 12 again. Then, the character pattern data of the ``1'' line row in the vertical direction of the character pattern is written into the page memory 20. Similarly, the vertical direction '2' of the C character pattern.

3'...''When the read/write operation up to the 39'th line is completed, the write address counter 18 becomes ADR<28.0.
), the row address counter 11 is (0).

The line/scan counter 13 (ma(28, O)) is set respectively. This completes the writing operation of character pattern data for one line, but next, the line feed pitch is every 48 lines, so there are 8 lines left. 'O' is forcibly written to the page memory 20 for 8 lines.
' When writing is completed, write address counter 18
The address value of is the point 61 in FIG.
The row address counter 11 is (O) at D R (30, O).
).

The line and /scan counters are each set to their initial values (0, 0>). This completes the repeat writing operation, including the line feed pitch for one line.
Then, the next second line of character code data is transferred from the page coat buffer 9. When the transfer of character code data is completed, the row address counter 11 returns to the initial address (0). Thereafter, character pattern data on the second line is written in the same manner as writing the character pattern data on the first line. Therefore, when the input/output operation of the character pattern data on the second line is completed, the address value of the write address counter is ADR (60, 0), and the row address counter 11 is (
O) and line/scan counters are set to (0, O), respectively. In this way, the character codes of each line are sequentially patterned and the pattern data is written onto the page memory 20. Then, when a fl 'END' code indicating the last line is detected from the line buffer, the data writing operation of the character pattern is stopped. Then, the page code buffer 7 control circuit 7 forcibly sets the output of the output generator 15 to 0' via the signal line S13, and notifies the page memory control circuit 17 that writing of the character pattern data has ended.

After receiving the write end signal, the page memory control circuit 17 performs a 39-point ADR (A3VE) in FIG. ,A,
3HF)) Forcibly occupy 0'. Soshide No. 11
0' is written to the point in FIG. 39, and the entire operation of writing character pattern data for one page of the specified paper size to the page memory 20 is completed. The write address counter 18 is ADR (0, 0), the row address counter 11
is (O), line/scan counter 13 is (0,0)
All are initialized to .

Next, a case where the data sent from the host system 1 is image information will be described. When the image identification code shown in FIG. 10 is input to the decoder 5, the output of the decoder 5 is input to the main control section 6 via the signal line SO5. Main control section 6
It then determines that the input information is image information, and instructs the distributor 4 to input the next paper size data to the page memory control circuit 17 via the signal line SO6.

Therefore, the paper size data is sent from the distributor 4 to the data line SO7.
The data is input to the page memory control circuit 17 via the page memory control circuit 17. Next image data 1, 2. ...The image data up to m is sent from the distributor 4 to the page memory 20 via the data line S15.
is input. The method of inputting image data to the page memory 20 is performed as follows. When the page memory control circuit receives the paper size identification code, it stores the next image data at 32 points in Figure 11 (address ΔDR (0, O)).
The write address counter 18 is set to ADR (
0, O). Then, the data length for one line in the horizontal direction is determined from the paper size identification code by referring to a table in the page memory control circuit 17. Therefore, if the paper size of the image information to be input into the page memory 20 is A4, the data length of one line will be a value up to 44 points <A4HE) in FIG. 11, that is, A4HE'. Naturally, the length of the image information per line sent from the host system 1 is 'A4H'.
E', so image data 12 and image data 2 in FIG. ...Image data mj (data length is A4V)
F', and the number m of image data is the value of 47 points in FIG. 11, that is, A4VE'. Therefore, to the page memory 20, image data 1 in FIG. 10 is transferred to 32 points ΔDR (0,0) and 34 points AD in FIG.
R (0°△4HE), image data 2 is a line of 51 points, image data 3 is a line of 52 points 1...
...The image data m is a 37-point line, so the final address is a 40-point ADR (A4VE, A41-IF
). Image information is written into the page memory 20 while controlling the write address counter 18 in this manner.

The character pattern data 13 written in the page memory 20 in this manner is sequentially outputted to the latch 21 . Gate circuit 23. Data to be printed is sent to the print control section through the interface 22 and the interface bus S17. In Fig. 8, 8.17 is a status data line from the print control unit, 818 is a command data line for specifying the operation mode, etc. to the print control unit, and S19 and S20 are strobe signals when sending command data and print data. S21 is a busy signal line from the print control unit, S22 is a horizontal synchronization signal line from the print control unit, S23 is a page end signal line that also indicates the end of print data, and S24
is a ready signal line of the print control unit, S25 is a printer 1 to request signal line that indicates a printable state, and 826 is a select signal line (826) that specifies the data content of the data line in the interface bus 817. 2 lines).

Reference numeral 827 is a print start signal line that instructs the print control section to start a print operation.

To explain in more detail when data is sent to the print control section, printing from the data control section 2 is started via the start signal line S27.
In response, the print control section sends a horizontal synchronization signal S22.

With this horizontal synchronizing signal S22, each data of the 32-point line in FIG. S2
2, the address is sequentially changed line by line according to S23, and the page end signal S23 is sent from the print control section.
This operation is repeated until the page end signal MS23 is received, and the data in the designated area of the page memory 20 is sent to the print control unit.Then, when the page end signal MS23 is received, data sending is forcibly stopped. . The print control section outputs the page end signal S23 at the same timing as the horizontal synchronization signal S22. Also, in relation to the memory addresses in Figure 11, the last line △3 of the memory area for that paper size is output to the 46 point 1, and the output from the print control unit is at the same timing as or earlier than the 47 point for A4. Ru.

Further, in the page memory control circuit 17, the page memory 20
J: When the sending of print data starts, one read address counter and 18 write address counters are always set.
If the value of the read address counter is larger, control is performed to permit a write operation to the memory area for which the data transmission has been completed.

Therefore, the loss of writing time to the page memory 20 is greatly reduced.

FIG. 13 shows a block diagram of the print control section 100 in FIG. 1. In FIG. 13, 101 is the print control section 100.
A microprocessor 102 is an interrupt control circuit for controlling interrupts to the microprocessor 101, and a command signal line S30. Page end signal line S29 from print data write control circuit 19. Interrupt request signals from each of the timeout signal lines 828 from the general-purpose timer 103 are sent to the microprocessor 10.
Tell 1. A general-purpose timer 103 generates basic timing signals for controlling paper conveyance, drum rotation processes, and the like. In this embodiment, this general-purpose timer 103 has 10
It is set to m5ec. Reference numeral 104 is a ROM (read only memory), which contains all control programs for operating the print control section 100. 105
are the same <ROM and contain a data table different from that of the ROM 104. The contents of the data table are
Shown in Figure 5 (△). In Figure 145 (A>, the address <
4-000,4001) is data for top margin control in case of paper size △3.

Addresses < 4002, 4003 are bottom margin control data, addresses (4004, 4005) are left margin control data, addresses (4006, 400
7), the data for lie 1-margin control is
). Similarly, the address (4008-4.00
F> contains data for controlling the top, bottom, left, and right margins for paper size B4.

Each address below (up to address (4087))! Contains margin control data corresponding to paper size F. Soshi-C1
These margin control data are used as set data for a margin control counter in a print data write control circuit 119, which will be described later.

Addresses (4,100 to 41FF) contain a dupple of command codes for specifying operations from the data control section 2, and are used for checking command codes from the data control section 2. The content of the command is a top/bottom margin change table.

These include a top margin adjustment table, a cassette upper/lower adjustment table, a cassette/manual feed adjustment table, etc. Addresses (4200 to 4.2 FF) contain data on the charging characteristics of the photosensitive drum 301, including five types of data A to F. This data is used for temperature correction control of the charging charge V304, which will be described later. Addresses (4300 to 43FF>) are exchange data tables, including photosensitive drum 301, developer 30
Contains each replacement cycle data of the developer in 7 and the fixing roller 332.

Addresses (4400 to 47FF) serve as a control timer table containing various timer values for performing printing operations, such as each process timing and paper feed timing.

106 is a RAM (random access memory), which is a working memory, and includes a timer (TIM) A as shown in FIG.

Contains a paper size register B, . . . , E2 (stores cassette size data based on signals from cassette size detection switches 320 and 324, which will be described later), status register 6, and other contents. The microprolet't
-101 compares the cassette size stored in the paper size register with the size of recording information (image data, etc.) from an external device sent from the data control unit 2,
If the size is thicker (pull it) to the cassette 1, it will issue a print operation command to the print control unit 100 in the subsequent stage.Therefore, even if the print paper is larger than the information sent from the outside, it will print. It is possible to improve the utilization rate.1
Reference numeral 07 is a non-volatile RAM, and the data in the memory is retained even when the power is turned off. In addition, the non-volatile generation RA
The data contents in M are shown in FIG. 45(B). Figure 45 (
In B), the address (6000) contains the drum characteristic number input from the operation unit in the exchange mode.
The address (6100) contains jam information when a jam occurs, and is used to prevent forgetting to dispose of jammed paper in the machine when the power is turned off in the event of a jam. Address (6200) is a paper discharge tray counter that counts the sheets in the reversing tray 381, and is incremented by 1 each time one sheet of paper is sent to the reversing tray 381. When this count value reaches a predetermined value, the tray becomes full and a message is displayed on the operation unit to prompt the operator to take out the paper from the tray. Further, the main paper discharge tray counter is automatically cleared when paper is removed from the tray by the operator. Therefore, even if the power is turned off, the number of sheets remaining in the tray is kept in the book counter.

Address (6300) is a drum exchange counter, which counts up by 1 for each print. When the value of this counter reaches the value of the replacement table (drum) shown in FIG. 45 (A>), the operator is informed by the display on the operating section that the drum should be replaced.

Address (64, OO) is a developer exchange counter, which is incremented by 1 for each print as in the case of drum exchange, and the value of this counter corresponds to the value of the exchange table (developer) in Fig. 45 (A). Displayed on the operation panel when the target is reached.

Address (6500) is a fixing roller replacement counter, which is counted up by 1 for each print as in the case of drum replacement, and when it reaches the value in the replacement table (fixing roller) shown in FIG. 45 (Δ), the operation panel to be displayed.

108 is a power supply sequence circuit, and the non-volatile generation RA
It has the function of preventing erroneous operation when turning on or turning off the power of M107. 399 is a power supply device that supplies power to the control section. Reference numeral 110 denotes an input/output boat that outputs display data to the operation display section 111 and reads data on each operation switch. Reference numeral 112 denotes an input port for reading input data from each detector 113 in the print control section 100. 116 is a motor, high voltage power lamp, solenoid,
Drive elements such as fans and heaters are shown. 115 is a drive circuit for the drive element 116; 114 is a drive circuit for the drive circuit 1;
This is an output port that provides an output signal to 15. 312 is a laser scan motor for operating the laser beam, 118 is a drive circuit thereof, and 117 is an input/output port that provides a drive control signal to the drive circuit.

344 is a semiconductor laser, 120 is a laser modulation circuit that performs optical modulation of the semiconductor laser, and 346 is a beam detector that detects the light beam operated by the laser scan motor, and a high-speed response PIN diode is used. It's been done.

121 is a high-speed comparator that digitizes the analog signal from the beam detector and creates a horizontal synchronizing pulse; 119 is a high-speed comparator that digitizes the analog signal from the beam detector; This is a print data write control circuit that controls writing to the test pattern and generates a test pattern print error. Reference numeral 122 is an interface circuit that controls output of the data stator to the data control section 2, reception of command data and print data from the data control section 2, and the like.

The details of the main blocks in FIG. 13 will be explained below. Figure 14 shows various detectors 11 in Figure 13.
FIG. 3 is a detailed circuit diagram of No. 3. In FIG. 14, signals from various detectors are input to a multiplexer 139. In the multiple playback mode, the select signal 331 causes the 8-bit signal S32 to select the input ports 1-112 in FIG.
is input.

320 is a single-stage cassette 1 size detection switch,
It is composed of four switches, and the paper size is expressed by the combination of them. 324 is a size detection switch for the lower cassette 1, and its configuration is the same as that of the upper cassette size detection switch. Reference numeral 319 is a cassette upper paper out switch, and the switch is turned on when there is no paper left in the cassette. 323 is a lower paperless switch. , 123 is a pass sensor in front of the registration roller, and a CDS light receiving element is used. This sensor has a bias voltage applied through a resistor.
The output voltage changes depending on the presence or absence of paper (not shown). Therefore, by inputting the output to the comparator 124 to which the reference voltage ref1 is applied, a signal for determining the presence or absence of paper can be obtained.

Reference numeral 326 indicates a manual feed switch that detects the paper from the manual feed guide 325, 336 indicates a paper ejection switch located on the fixing roller section, and 395 indicates a paper ejection switch located on the paper ejection tray section. Reference numeral 125 indicates a toner out detection switch for detecting the absence of toner in the toner box, and 126 indicates a toner full detection switch which operates when the toner bag is full of toner.

Reference numeral 127 is a sensor for detecting the specific toner concentration of the developer (probe concentration detection sensor), and a photodiode is used. A bias voltage is applied to this sensor via a resistor, and the output voltage changes depending on the toner concentration. Therefore, by inputting the output to the comparator 128, since the reference voltage vrer2 is applied to the other input terminal of the comparator 128, a signal of 1 or O is obtained when the toner concentration is above or below the specified value, respectively.

129 is 0N10FF by opening and closing the front cover.
130 is a temperature fuse installed in the fixing device, and 131 is an MC relay that turns the driving cloth source (+24VB) on and off. Since one side of the temperature fuse 130 is connected to the power source -1-24V A, if the temperature fuse 130 is blown out due to the operation of the fixing device, the MC relay 131 is turned off and the driving power source is turned off. Further, the temperature fuse 130 has a resistance R
One of the resistors RO1 is connected to the resistor RO2.
and the input of the comparator 132. Also=
The other input of the 1 amparator 132 is the reference voltage Vref3.
is applied. Therefore, when temperature fuse 130 blows, the input of comparator 132 becomes OV. Therefore, the comparator 132 outputs a temperature fuse blowout detection signal. 133 is a destination selection switch, and specifically, by turning this switch ON/OFF,
The ON state is for domestic use (A and B sizes), and the OFF state is for the US (legal and letter size). Therefore, for example, even if the combination of codes by the upper or lower cassette size switches (4 pieces) is the same, the paper size of either domestic 2 or US paper size is selected depending on the state of this switch.

134 is a jam release switch, which is installed inside the front cover. This switch is a switch that is turned ON for confirmation after the operator calls for a paper jam or full toner, after the operator clears the jam or replaces the toner bag. Therefore, after the above processing, this switch is ONL.

Otherwise, the jam or full toner display on the operation panel will not be cleared. Reference numeral 92 is a paper discharge tray sensor shown in FIG. 5 that detects paper in the tray. A thermistor 334 detects the temperature of the fixing device, and the temperature detected by this thermistor is controlled to be constant. The output of the thermistor 334 is connected to the resistor RO3 and to the input sides of the amparators 136 and 137. Therefore, the input voltage of the comparator changes as the resistance value of the thermistor 334 changes due to temperature.

That is, as the temperature increases, the input voltage increases.

The other input terminal of the comparator 136 has a resistor RO6
A voltage divided by and RO7 is applied, and the output of the amparator 136 changes depending on whether it is higher or lower than the divided reference voltage. Also, resistors RO6 and R
A resistor RO8 is connected to the connection point of O7, and one end of the resistor RO8 is connected to the collector of transistor 138. Therefore, when this 1-transistor 138 is turned on by the input signal (power save signal) S3, the comparator 13
The reference voltage of 6 is lowered by resistor RO8, and the fuser temperature control is lower than when transistor 138 is 0FFI. Therefore, the power consumption of the fixing device becomes low and the fixing device enters a power save state. Also, comparator 13
The reference voltage 7 is given by the voltage division of resistors RO4 and RO5. Since the reference voltage of the comparator 137 is set considerably lower than the reference voltage of the comparator 136, it is possible to detect a temperature drop in the fixing unit due to heater disconnection or heater drive circuit failure during printer operation. can. The output 333 of the comparator 136 is input to a multiplexer 139 and read by the microprocessor 101.

Note that this input signal is used to detect the ready state of the fixing device. Further, it is used as a drive signal for the fixing device heater lamp 333 in FIG. 15.

342 is a drum temperature sensor that detects the temperature near the photoreceptor 301. The output side of thermistor 342 is connected to resistor R58 and the input of operational amplifier 270. Therefore, the resistance value of the thermistor 342 also changes depending on the temperature change near the photoreceptor 301. Therefore, operational amplifier 2
The input voltage of 70 also changes. The operational amplifier 270 outputs a low voltage when the temperature of the photoreceptor 301 is low, and a high voltage when the temperature is high. operational amplifier 2
70 is a voltage follower, and its output is
It is connected to the input of the A/D converter 271. Then, the output voltage of the operational amplifier 270 is converted into a digital value by the A/D converter 271 and read by the microprocessor 101 through the multiplexer 139. This A/D-converted temperature data of the photoreceptor 301 is used for later (e) charging correction of the photoreceptor 301. 44
0 is a cassette upper/lower adjustment switch, 441 is a cassette/manual feed adjustment switch, and 442 is a top margin adjustment switch.

FIG. 15 is a detailed block diagram of the drive circuit 115 and output element 116 in FIG. 13. In FIG. 15, 141 is a developer motor, and a DC-driven Hall motor is used. Reference numeral 140 is a driver for the developer motor, which performs PLL control. 143 is a fixing device motor, and a DC-driven Hall motor is used.

142 is a driver for the fuser motor 143;
Performs PLL control. 145 is a fan motor for cooling the inside of the machine, and a DC-driven Hall motor is used. 144 is a driver for the cooling fan motor, which is similar to the developer and fixing device driver described above;
LL speed control is not performed. Reference numeral 147 is a motor for driving the photosensitive drum 301, and a four-phase pulse motor is used. 146 is a driver for the drum motor 147, which employs a constant current 1-2 phase excitation system. The speed is approximately 1200 PPS, which is the speed at which vibrations are less likely to occur. 149 is a registration motor that drives the registration roller 329 and manual feed roller 327, and is a pulse motor. 148 is a driver for the registration motor, which uses a constant voltage two-phase excitation system. The speed is about 400PPS.

Note that when the registration motor 149 rotates in the normal direction, the registration roller 329 rotates, and when the rotation direction is reversed, the manual feed roller 327 rotates. These are transmitted via a one-way clutch.

151 is a lower paper feed roller 322 and an upper paper feed roller 3
The paper feed motor that drives 18 is a pulse motor. As above, forward and reverse rotations are transmitted via a one-way clutch. Reference numeral 150 denotes a driver for the paper feed motor 151, which uses constant voltage two-phase excitation similarly to the registration motor driver 148. The speed is about 400PPS.

Reference numeral 302 denotes a static elimination lamp that removes residual charges from the photoreceptor 301-1 before charging, and is composed of a plurality of red LEDs. R10 is a current control resistor for the static elimination lamp 302, and 152 is a driver for the static elimination lamp 302. 303 has a pre-transfer static elimination lamp C placed before the transfer charge V to increase transfer efficiency, and has multiple red LEDs.
It consists of R11 is a current control resistor for the pre-transfer static elimination lamp, and 153 is a driver for the pre-transfer static elimination lamp. 158 is a solenoid for the toner collection blade, and when this solenoid is turned on, the photoconductor 301
The blade 310 is pressed against. 154 is a driver for the blade solenoid 158. Reference numeral 159 denotes a toner replenishment motor for replenishing i~lunar from the toner hopper to the developing device 307. When this toner replenishing motor rotates, the toner is supplied from the toner hopper to the developing device 307.
Replenish toner. The operation of the toner replenishing motor 159 is performed according to the output of the sensor after detecting the prologue concentration shown in FIG. 14. 155 is the toner supply motor 1
59 driver. 131 is an MC relay that works in conjunction with the door switch similar to that shown in FIG. 14, and 15
6 is its driver. As shown in FIG. 15, the power supply side common for motors, lamps, etc. for which the MC relay 131 is omitted is connected to the contact 163 of the MC relay 131, and the other contact is connected to the +24VB power supply. When ON l, T,
The structure is such that the motor and lamp can be operated.

304 is a charger for charging, and the case of the charge V- is connected to the ground of the aircraft body.

The corona discharge wire of the charger is connected to the high voltage power supply 338.
is connected to the output terminal of the charging high voltage power supply 160,
For the input of the high voltage power supply for charging, the high voltage output is 0N10FF=
An analog control signal line S36 for changing the high voltage output current is connected to the signal line S35. Further, the analog control signal line 836 is connected to the D/A converter 165, and the data on the charging voltage control data line S37 from the microprocessor 101 causes the D/A converter 165 to
"c is converted into an analog voltage and controls the output current of the high-voltage power source for charging. 306 is a charger for peeling, and the peeling charger 306 is connected to the output of the high-voltage power source for peeling 161. The high-voltage power source for peeling has an AC output and A transfer charger 305 is used to transfer the developed toner on the photoreceptor 301 onto paper, and the transfer charger is connected to the output of the transfer high-voltage power supply 62.The transfer high-voltage power supply is connected to the transfer high-voltage power supply 62. In addition to the charger output, a developer bias power source is also incorporated, and its output line 838 is connected to the developer magnet roller 308. This voltage applies a bias voltage to the magnet roller 308, providing a developing bias. 33 is a heater lamp of the fixing device, and one side is connected to one side of the 8C100V power supply.

The other end is connected to the second contact 164 of the MC relay 131, and the other end is connected to the heater drive circuit 166. Therefore, the heater lamp 333 is connected to the MC relay 1.
It operates only when 31 is ON. Also, heater drive circuit 1
Two input signals 833 and 839 are input to 66, and S33 is the thermistor 33 in the fixing device shown in FIG.
4, which is a density control signal for the fixing device. S
39 is a forced OFF signal for the heater lamp 333 from the microprocessor-101.

Figure 16 shows the laser scan motor 3 in Figure 13.
12 and its driving circuit 118. FIG. 16th
In the figure, 312 is a circuit diagram inside the laser scan motor. LO2, LO3, and LO4 indicate motor coils, and 180, 181, and 182 are ball elements that detect the position of the motor rotor, respectively. 183,18
4,185 is a comparator for the Hall elements 180, 181, 182, the output of which is connected to the base of the power transistors 171, 172, 173 which drive the motiles LO2, LO3, LO4 in the drive circuit 118, and resistors R26, R27. , R28.

Furthermore, base resistors R23, R2 are connected between the bases and emitters of the power transistors 171, 172, and 173.
4 and R25 are connected to each other. As the rotor of the motor rotates, the Hall elements 180, 181, 182
are turned on in the order of 180, 181, and 182.

Therefore, the outputs of comparators 183, 184, and 185 are also 1.
The level becomes LOW in the order of 83, 184, and 185. Therefore, the power transistors 173, 172, and 171 are turned on in the order of LO2, LO3, LO4, and the driving voltage is applied to the laser scan motor 312
rotates. In addition, the output of the comparator 185 is passed through a diode DO2 to a resistor R30 and a capacitor CO6,
The signal is inputted to a frequency division counter 175 through a waveform shaping circuit including an inverter 174. The outputs of output ends Q1 and Q2 of the frequency dividing counter 175 are connected to motor speed switching gates 176 and 177, and the output of the speed switching gate is passed through an OR gate 178 to a PLL (phase, lock, loop) control IC. FG large input is connected. Further, one input of the speed switching gate 176177 is connected to the output of the speed control signal line 840 and the inverted output of the signal line A. Therefore, when 840 is at the LOW level, the switching gate 177 is enabled and the output of 01 of the frequency division counter is the PLI-control! llIC167's "
When S40 is at HIGH level, the switching gate 176 is enabled, and the output of the frequency division counter 175Q2 is inputted to the FG large input of the PLI-control l0167. Here, to briefly explain the input/output signals of the PLL control IC 167, the P/S terminal (PLAY/5TOP> stops at the treble level and starts at the LOW level).

In the case of HIGH level, the common power of both terminals of AGC and APC becomes HIGH level. FGIN is the rotation motor pulse signal input from the motor to be controlled.

N1. N2 is a signal for switching the frequency division number of the reference frequency divider inside this IC, 33/4b is a switching signal for the motor rotation speed, CPO
UT is the crystal reference frequency division output signal, CPIN is the reference frequency input, and LD is the lock detection signal. When the motor rotation speed is within the lock range, it is at l-I IGH level, otherwise it is L.
OW level is output. AFC is the output of the motor's speed control system, and PLL is the output of the 8-bit D/A converter inside the IC. APC is the output of the motor's phase control system.
This is the output of the 8-bit D/A converter inside the IC.

Also, the XOI connected to the PLLIC167 is a crystal oscillator for generating a reference frequency (CC)1. GO2 is an oscillation capacitor.

The output terminals of the eight FC and APC of the PLL control IC 167 form an adder circuit with resistors R12 and R13, and are connected to one side input terminal of the A pair 168. operational amplifier 1
68 + side input terminal, +12V is connected to resistors R14 and R1
A voltage divided by 5 is applied. A negative feedback circuit is formed by the resistor R16 and CO3, and in particular, the capacitor CO3 serves as a bypass filter.

Therefore, the amplification degree of the operational amplifier 168 is such that it has a characteristic of attenuating inputs having a certain frequency or higher. The output of the operational amplifier 168 is connected to an input terminal of a pulse width modulation switching regulator IC 169. 169
is a commercially available pulse width modulation switching regulator IC. Book l0169 and power 1 to transistor 1
70. Diode D01. Coil LO1, capacitor C
Together with O5, it constitutes a down switching regulator circuit. In the input/output of IC169, one terminal is a comparison reference voltage terminal, and the reference voltage output terminal V inside TC169.
A reference voltage obtained by dividing the RFF voltage by resistors R17 and R18 is applied. The DEADT IME terminal regulates the maximum pulse width of the output, and connects the VRFF to the resistor R.
19, and a voltage divided by R20 is applied.

C1 and C2 are output terminals, and the pulse width changes depending on the voltage value of the input terminals. In other words, when the + side input terminal voltage is lower than the one side input terminal voltage, C1 and C2 are LOW.
The path width on the level side becomes smaller, and the width in which power 1 to transistor 170 is turned on also becomes smaller.

Therefore, the voltage across the capacitor CO5 also becomes smaller.

Moreover, if the + side input terminal voltage is higher than the one side input terminal voltage, 01. The pulse width of C2 increases, and the voltage across capacitor CO5 also increases.

The rotation speed control of Scan Tanabata-312 will be explained below.

Rotation start signal S42 of scan motor 312 is LOW
When the level is reached, the AFC of P l-1 control IC167
, AFC Ryokawa force is at IOW level until the aforementioned lock signal S41 is output, so operational amplifier 1
The output of 68 is a +''IGH level voltage. Therefore, the output pulse width of the regulator IC 169 is as high as 169, and the voltage across the capacitor CO5 is about +16V. Since any one of the Hall elements 180, 181, 182 is turned on at the position where the motor rotor is stopped, the motor coils LO2, L03,
The coils corresponding to the Hall elements 180, 181, and 182 of LO4 are excited, and the scan motor 312 starts rotating. The scan motor 312 then rotates at the top. The level of speed control signal line S40 is now HIGH
Therefore, the Q2 output of the frequency division counter 175 is
It is applied to the FG input terminal of the PIL control IC 167. Therefore, the frequency division counter 175 functions as an 8 frequency division circuit. The frequency of the signal applied to FGIN is P L-LI0
When reaching approximately 96% of the reference frequency inside the 169, the lock signal LD S41 becomes HIGH.The FC and APC output levels are not fixed at 10W level (OV), but are
It is switched to the output voltage of the L I C internal D/A converter. Therefore, from now on, the scan motor 312 is controlled to a constant speed by the speed control system output AFC and the phase control system output APC.

Further, in this embodiment, when a print command is not received from the data control unit 2 for a certain period of time (approximately 5 minutes), the scan motor enters a standby state and the output of the speed control line S40 is L.
Become OW level. Therefore, the frequency divider 175 divides the frequency from the previous frequency by 8 to 4, so the scan motor has a rotation speed of 4/8, that is, 1/2. This is to perform half-speed control as described above in order to prevent problems with reliability of the motor's bearings, etc., from occurring if the motor rotates at high speed for a long period of time. In this embodiment, during printing operation, that is, during high-speed rotation, approximately 12. OOOrpm, approximately 600 during standby
Orpm.

FIG. 17 is a detailed circuit diagram of the laser modulation circuit 120 and the semiconductor laser 344 in FIG. 13.

In Fig. 17, C1344 is a semiconductor laser diode, which consists of a one-node diode body 25 that emits light.
It also consists of a monitoring diode 260 which is a photodetecting means for monitoring the output beam intensity from the laser diode 259. Reference numeral 257 is a high frequency transistor which is a voltage-current conversion means (or first current driving means) and performs optical modulation of the laser diode 259. Resistor R50 is a current detection resistor, 258 is a transistor serving as a second current driving means for passing a bias current to the laser diode 259, and R51 is a current limiting resistor thereof.
R52 is the base current limiting resistor of transistor 258. 254, 255, 256 are laser diodes 25
9. Each analog switch has a high speed analog switch for applying modulation to the gate (G).
When a voltage of l-( level is applied, the resistance between the drain (D) and source (S) becomes low and turns ON. When a voltage of IOW level is applied to the gate (G), conversely, the resistance becomes high and turns OFF. The output power of the laser 259 has three levels in this laser printer.
By turning on the analog switch 254 with an output P(ON) that almost completely removes the charged charge of 01, the laser diode 259 turns on the output P(ON).
becomes.

The second part corresponds to the black background on the paper, and is located on the photoreceptor 301.
In order to leave the electrical charge on the top as it is, the analog switch 25
By turning on the laser diode 259, the output of the laser diode 259 is turned off, that is, the output becomes P (OFF). The third one is for increasing the printing density of one dot line with the output P (St-1) between the first output P (ON) and the second output P (0 "F"), and the analog switch 255 is used to increase the print density of one dot line. By turning on the laser diode 259, the output P(S
H) (details of P(,5l-1) will be described later).

Resistors R42 and R43 are analog switches 254°255
．． Short circuit protection resistance when changing 0N10FF of 256, 249
, 250, 251 are the analog switches 254, 25
5,256 gate drivers. CO9, C10
, C11 is a speed-up] sensor, R47
, R48, R49 are the gate drivers 249, 25
The input resistance is 0.251.

246 is a 3NAND gate 1-, and when all three gate inputs are at HIGH level, the output becomes LOW level, turning on the alilog switch 254, and the laser diode 259 changes to the output P (ON> state). The first of the three input gates is connected to the output of the inverter 253, and the input of the inverter 253 is connected to the print data signal 547 (printing is not done at the IOW level, which prints at HIGH level).The second is invar
The input of the inverter 252 is connected to the shadow signal S48 (shadow on at HIGH level, off at LOW level). The third is connected to a laser enable signal 849 (laser enable at HIGH level, laser forced OFF at LOW level). Therefore, the output of the NAND gate 246 is LOW.
The conditions for this level are when the laser enable signal S49 is 1''IGH, the shadow signal 848 is LOW, and the print data signal 847 is OW. Next, 247 is 3NA
3 at the ND gate. all gate inputs are 1-11
When the level reaches G + - level, the output becomes LOW level, the analog switch 255 is turned on, and the laser diode 259 enters the output P (SH) state. The first of the three input gates is connected to the shadow signal 848, the second to the output of the inverter 253 which is the inverted signal of the print data signal S47, and the third to the laser enable signal S49. Therefore, the NAN
The conditions for the output of the D gate 247 to be LOW level are when the laser enable signal S49 is HIGH, the shadow signal 848 is HIGH, and the print data signal $47 is low and OW. Next, 248 is a 2OR gate, and when one of the two gate inputs becomes LOW level, the output becomes l-OW level, turns on the analog switch 256, and turns on the laser diode 259.
becomes the OFF state output P (OFF) state.

245 is a sample-and-bold IC, which converts the output of 25 laser diodes into the shadow output P (St
-1).

A N A 1. , OG-INPUT is an analog voltage input to be sampled, SΔMPI EC is a connection terminal for a hold capacitor CO8, and 5TROBL is a sampling strobe signal terminal, which is connected to a sample strobe signal S46. 237 is an operational amplifier with FET input, which constitutes a voltage follower circuit. DO3 is a Zener diode that regulates the output of laser diode 259 to be within the maximum rating. Further, the resistor R40 and the capacitor CO7 constitute an integrating circuit, and the resistor R41 is a discharging resistor that discharges the charge of the capacitor CO7 at a constant rate. 236 is an analog switch whose gate (G) is buffer 2
44, and a sample signal S45 is input to the input of the buffer 24/l. 253 is a transistor for level conversion, and R39 functions as a current limiting resistor when charging the capacitor CO7. R38 is transistor 2
35 is a base current limiting resistor, 234 is a comparator which is a comparison means, and this comparator is composed of resistors R34,
It has a hysteresis characteristic due to the action of R35.

] The output voltage of the laser monitor amplifier 232 is applied to the input side of the comparator 234 through the resistor R34. 232 is an amplifier for the output of the photodiode 260 that detects the optical output from the laser diode 259, and serves as current-voltage conversion means. Resistor R32゜R33, VROl is the operational amplifier 2
This is a resistor that regulates the amplification degree of 32. Therefore, by changing the volume VRO1, the amplification degree of the operational amplifier 232 can be changed. R31 is an output load resistance of the photodiode 260 in the semiconductor laser 3/I4, and a voltage proportional to the output current of the photodiode 260 is obtained. FIG. 19 shows the relationship between the short circuit current 1 s and the optical output PO of the photodiode 260.

In FIG. 19, ls indicates the monitor current, and 1]0 indicates the optical output of the laser diode 259. The output of P(ON) is approximately 6 mw, the output of P(SH) is approximately 4 mw, and the output of P(O
FF) is set to O. Also l A-A, l A-
8 represents two types of laser diode monitor characteristics. Normally, the Polycomb VROI is adjusted so that the output voltage of the operational amplifier 232 is about 3V when the laser diode optical output is 5mW. Therefore, even the characteristics of graphs LA-A and LA-B in FIG. 19 can be adjusted by the volume VROI.

238 is a comparator for checking whether the laser diode 259 is emitting light, and the output voltage of the operational amplifier 232 is applied to the negative input. In addition, on the negative side, the voltage is divided by resistors R36 and R37 (
In this case, a voltage of approximately 2.0 V is applied. Therefore, the laser diode 259 emits light, and its output changes from LOW level to HrGl-level, and a laser ready signal 843 is output. Further, a laser light amount setting voltage is applied to one input terminal of the comparator 234. The set voltage is given from either analog switch 240 or 241. That is, the analog switch 240 is turned ON when the laser output P(ON> is set), and the output voltage of the voltage follower 239 is applied to one side input of the comparator 234.The input terminal of the voltage follower 239 has a first voltage. The main exposure adjustment volume 360, which is a variable means, is inputted with a voltage divided by the resistor R45, and by varying the main exposure adjustment volume 360, the voltage at one terminal of the comparator 234 also changes. 241 is turned ON when the laser output P (SH) is set, and the voltage obtained by dividing the output voltage of the voltage follower 239 by the resistor R46 and the shadow exposure adjustment polycomb 361 which is the second voltage variable means is applied to the comparator 234. Provided to one side input terminal.The above Porty Schiff A lower 23
9, Ana 1 cog switch 240, 241, main exposure adjustment volume 360. Resistor R45, shadow exposure adjustment polycomb 361. The resistor R46 constitutes a light output setting means. Further, a circuit that compares the voltage detected by the monitor photo diode A-260 and amplified by the monitor amplifier 324 with a set voltage by the comparator 234, and integrates the comparison value is referred to as optical output stabilizing means.

The analog switches 240 and 241 are switched by the main exposure setting signal 844. That is, when the main exposure setting signal S44 is at the LOW level, the output level of the inverter 242 is 1-IJGI-.
It becomes the i level and the analog switch 241 is turned on. Further, when the main exposure setting signal S44 is at the HIGH level, the output of the buffer 243 becomes the l-11GH level and the analog switch 240 is turned on. The outputs (S side) of the analog switches 240 and 241 are also input to the voltage follower 261, and are used to correct the threshold level of the horizontal synchronization pulse detection comparator of the beam detection circuit described later.
The output S50 of is used.

Next, the current-output characteristics of the laser diode used in this printer will be explained. Figure 18 is I
It is a graph of F-Po characteristics. TC=O°C is the IF-Pa characteristic when the case temperature of the laser diode 344 is 0°C, same <TC=25°C is when the case temperature is 25°C, TC=5
0°C is the IF-Po characteristic when the case temperature is 50°C. Taking the characteristics of the case temperature TC=25° C. as an example, when the current IF without flowing through the laser diode 259 is gradually increased from 0, the optical output po starts to be output from a point of about 50 mA. Then, at the point of fF=68mA, the P(O
The optical output of N) is 6 mw.

Therefore, even when TC=O°C, the optical output po starts to be output at a point of about 40 mA, so by turning on the transistor 258, the bias current IFB is always maintained when the laser enable signal 849 is at the HIGH level. The power loss of the laser modulation transistor 257 is reduced. Therefore, extremely stable operation of the laser modulation transistors 1 to 257 is guaranteed even at high temperatures due to the action of the bias current IFB. In addition, if the amount of change in current required to modulate the laser beam is, for example, TC = 25°C, the value of 1F25 - IFB should be used. Compared to directly driving the current of 1F25 with the transistor 257, the light intensity is stabilized as described below. The accuracy of the conversion operation can be predicted quite well.

Furthermore, as is clear from the graph, the output of the laser diode itself varies considerably depending on the temperature, so the light amount stabilizing circuit is required. The stabilizing circuit detects the amount of light from the laser diode 259 with a monitor photodiode 260, and is controlled so that the short circuit current is of the photodiode 260 is always constant. This is because, as is clear from FIG. 19, the monitor short-circuit current Is and the laser diode 259
Since the optical output PO is in a perfect proportional relationship, if the monitor current 1 s is kept constant, the optical output PO is always kept constant.

Furthermore, since the temperature-related drift of the photodiode 260 is very small, even if the temperature changes, the amount of change in optical output can be ignored. Next, the operation of the above-mentioned optical output stabilizing circuit will be explained using FIGS. 17 and 20.

In FIG. 20, when the laser enable signal S49 and the sample signal 845 both go to HIGH level, the first
The transistor 258 in Figure 7 is turned on, and a bias current (approximately 3
0mA) flows.

Also, at this time, since both the print data signal S47 and the shadow signal 848 are at LOW level, the gate 2
Out of the analog switches 254, 247, and 248, the inputs of only the gate 246 are all at the HIG level, so the output becomes the LOW level, and the analog switch 254 among the analog switches 254, 255, and 256 is turned on. In addition, when the lean pull signal S/15 becomes HIGI-(, the analog switch 236 is turned ON. At this time, the capacitor CO7 is not yet charged, so the output of the operational amplifier 237 is OV, and the laser modulation is performed. The base of the transistor 257 also becomes OV. Therefore, at this point, only the bias current flows through the laser diode 249, and the laser diode does not emit light, as can be seen from the characteristics shown in FIG. 18. Photodiode 260 for monitoring the laser diode Since the laser is not emitting light, the monitor current Is is O, and the output of the operational amplifier 232 is OV.] The output of the comparator 234 becomes LOW level, and the transistor 235 is turned off.

Since the transistor 235 is OFF, the capacitor C'
07 is charged through resistors R39 and R40.

be done. This resistance when being charged is R39゜R40
, the time constant of capacitor CO7 is selected to be approximately 20 to 50 msec. If this value is very small, the response of the stabilizing circuit will be too fast, and the fluctuations in the optical output level of the laser will become large. Moreover, if it is too large, the responsiveness will deteriorate and it will take time for the optical output to stabilize. By charging the capacitor CO7, the voltage follower 23
7's output voltage also gradually increases. Therefore, as the base voltage of the laser modulation transistor 257 rises, a current flows to the collector. At this time, the collector current Ic of the transistor 257 is (VB-VBE(SAT))/R5
The current value of 0 is loud. A sum current IF of the bias current IFB from the transistor 258 and the current IC from the transistor 257 flows through the laser diode 259 . Then the current 1c increases and the laser diode 2
The forward current IF of 59 is approximately 50mA (TC=2
5° C.), the laser diode 259 emits light. When the laser diode 259 emits light, the monitor current of the monitor photodiode 260 flows in accordance with the emitted light output, and the A amplifier 23
The →-input terminal voltage of 2 increases, and its output voltage is also an amplified value of the input voltage. and op amp 232
The amplification degree of is adjusted in advance by the volume VRO1 so that the output voltage of the operational amplifier 232 is approximately 0.5 V for the output of the laser diode 259 of 1 mW, so the optical output of the laser diode 259 increases and the output voltage of the operational amplifier 232 is approximately 0.5 V.
w, When the output voltage of the operational amplifier 232 reaches approximately 1V, the output signal size of the comparator 238, that is, the laser ready signal S43 changes from i, OW to )-ITGl- level. Since the main exposure setting signal 344 is at LOW level at one side input terminal of the comparator 234, the shadow exposure level (light output P(
St-1)) Voltage is applied. This voltage depends on the sensitivity characteristics of the photoreceptor 301.The shadow exposure level voltage is
It is set by a shadow exposure setting polycomb 361 in the operation section. Now, the voltage corresponding to the average value of 4mW of optical output is 2. Suppose that Ov. Therefore, when the optical output of the laser diode 259 increases and the voltage at the input terminal of the comparator 234 exceeds 2.0■, the transistor 2
35 is turned on, and capacitor CO7 is discharged through resistor R40. Therefore, the base voltage of the laser modulation transistor 257 also decreases, and the optical output of the laser diode 259 becomes 4 mW or less. When the optical output of the laser diode 259 becomes 4 mW or less, the →-side large input terminal voltage of the comparator 234 becomes 2.0 V or less, and the transistor 235 is turned off again.

Then, capacitor C7 is charged up again through resistors R39 and R40. Then, the laser diode 259 again changes its optical output around 4 mW, and the comparator 234 repeats the 0N10FF operation at a constant cycle. In addition, since this comparator 234 has hysteresis characteristics, comparison judgment becomes stable.
Be able to make reliable judgments. And the resistor R3
9 and R40, the voltage across the capacitor CO7 approaches the value of VOl in FIG. 20 and becomes stable. After the laser ready signal 343 becomes HIGH level, the microb[] processor 101 outputs a shadow level sample strobe signal S46 after a predetermined time t6 has elapsed through the output port. Sample strike [J-
When the output signal is output, the sample hold IC 245
The voltage VO1 (FIG. 20) of the capacitor CO7 input to the ANALOG-INPUT input terminal is sampled and held, and the voltage is stored in the hold capacitor CO8. Therefore, after the sample strobe signal is turned off, the control voltage VO1 for outputting the shadow level P(SH) continues to be output to the output OU1- of the sample and hold IC.

Next, when the sample and hold operation of the shadow level P(SH) is completed, the microprocessor 101 switches the main exposure setting signal S44 to HIG + - level through the output port. Therefore, the output voltage of the voltage follower 239 is applied to one input terminal of the comparator 234 through the analog switch 240. The output of the voltage follower 239 has the main exposure level (light output P (
ON)) voltage is being output. This voltage is applied to the photoreceptor 30
It is assumed that the voltage is set by the main exposure setting polycomb 360 in the operation unit according to the sensitivity characteristics of 1, and that a voltage of 3.0■ corresponding to an average light output of 5 mw is currently being output. . Therefore, the output of the comparator 234 has one input terminal set to 3. L due to switching to OV
The signal becomes OW level and the transistor 235 is turned off. Therefore, as the capacitor CO7 is further charged up, the base voltage of the laser modulation transistor also increases, and the optical output of the laser diode 259 also increases. And the optical output of the laser diode 259 is (3m
When it comes to around w, the output voltage V232 of the operational amplifier 232
becomes approximately 3V. When the output voltage of the operational amplifier 232 becomes 3■ or higher, the output of the comparator 234 changes to 1-11 GH, the transistor 235 turns on, and the capacitor CO7 becomes the resistor R4.
Discharged through 0. Therefore, the base voltage of the laser modulation transistor 257 also decreases, and the optical output of the laser diode 259 becomes 5 mW or less. When the optical output of the laser diode 259 becomes less than 3 mW, the voltage at the + side input terminal of the comparator 234 also becomes less than 3.0 V, and the transistor 235 is turned off again.
The capacitor CO7 is charged up again through the resistors R39 and R40, and the optical output of the laser diode 259 becomes 5 mW or more.

In this way, the comparator 234 repeats the 0N10FF operation at a constant cycle when the optical output of the laser diode 259 is around 6 mW. And the resistors R39 and R4
Due to the integral effect due to 0, the voltage of capacitor CO7 becomes
It approaches 0 figure VO2 and becomes stable. When the setting of the main exposure level is completed, the microprocessor 101 starts the operation of a zumbling timer, which will be described later, and writes print data to the photoreceptor 301. The sample timer is triggered one after another at a constant period T every time a laser beam detection signal, which will be described later, comes, and outputs the sampling signal S45 only in a portion other than the print data writing operation, that is, in the section shown in FIG. 20a. Since the sample signal 84.5 is at the LOW level in the section of the print data 847 and the shadow data 848, the analog switch 236 is turned off. Therefore, the laser diode 25 is activated by the print data D47 and the shadow signal 848.
9 is a laser diode 259 in the printing area to be modulated.
The optical output level of P (ON), P (
SH), P (OFF>).The first is when the print data signal s47 is OFF, that is, OFF.
'NAND' when the shadow signal is OFF or LOW level at W level (white output for printing)
Gate 246 is established and only analog switch 254 is turned OFF.
N, the main exposure level voltage VO2 is applied to the base of the modulation transistor 257, and the optical output of the laser diode 259 becomes P(ON)=6 mw. The second case is when the print data signal S47 is OFF and the shadow signal is ON (the printing output is halftone), and N
AND gate 247 is established and analog switch 255
is turned on, and the output voltage VO1 of the sample and hold IC 245 is applied to the base of the modulation transistor 257.
is applied, and the optical output of the laser diode 259 is P(
S)-1)-4mw. The third is the print data signal 84
7 is ON and the shadow signal is OFF (the output of printing is black), the OR gate 248 is established and only the analog switch 256 is turned ON. Therefore, the base of the modulation transistor 257 is connected to GND and OV
Therefore, the optical output of the laser diode 259 is P (
OFF) = 0 and no light is emitted. In this manner, the first printing is performed. As soon as printing is completed, the microprocessor 101 sets the main exposure setting signal 344 to LOW level again through the output port, and resets the shadow exposure level P (SH). Therefore comparator 2
The voltage at one side input terminal of 34 becomes 2.OV. which is the setting voltage of the shadow exposure level. Therefore transistor 2
35 is turned on, the capacitor CO7 is discharged, and the VCO7 becomes smaller. In order to explain the optical output stabilization operation of the laser diode, it is assumed that the case temperature of the laser diode 344 increases by .DELTA. during the second printing operation. As is clear from the characteristic diagram in Figure 18, as the case temperature increases, the IF-Po characteristic curve of the laser diode shifts to the right.
When the same current is passed through the laser diode 259,
The optical output PO will decrease. Therefore, in order to obtain the same optical output, {circle around (2)} must be increased by the current ΔIF corresponding to the shift of the characteristic curve to the right. Therefore, the voltage VCO7 of the capacitor CO7 is set to VO3 which is higher than the first set voltage VO1 by the voltage △V1 corresponding to IF, and the optical output of the laser diode 259 becomes the first set voltage VO1.
P(S'l-1-1)=4 is set, which is the same as the setting for the second time. Then, like the first time, sample strobe signal S4
6, the shadow exposure level P (ON) is set in the sample hold IC 245. At this time as well, the operation corresponds to the rise in the temperature of the case of the laser diode 344, and the voltage of CO7 is set to VO4, which is higher by the correction voltage △v2 due to the rise in humidity, and after setting, printing of the same number on cylinder 2 is performed. . In this way, the shadow exposure level P (St-1) and the main exposure level P (ON
> is maintained at a constant level very accurately by the function of a stabilizing circuit, thereby making it possible to perform high quality printing. Incidentally, as described above, the main exposure level P (ON) performs a light amount stabilizing operation so that the light output is always kept constant except during writing of print data. Furthermore, for the shadow exposure level, a sample hold operation is performed before each print starts, and unlike the main exposure level, a light amount stabilization operation during the print writing operation is not performed. This is because the circuit becomes complicated and expensive, and because the exposure level is an auxiliary element compared to fluctuations in the main exposure level, and even if it fluctuates somewhat, it does not have much of an effect on print quality. In addition, when changing the setting voltage input to the comparator 234 according to the sensitivity characteristics of the photoreceptor 201, the adjustment is made by changing the main exposure setting volume 360.

This main exposure setting polycomb 360 is adapted to vary the input voltage of the voltage follower 239.

Therefore, by varying the main exposure setting polycomb 360, the light output setting voltage at P (ON) can be adjusted. On the other hand, the optical output setting voltage at P(SH) is obtained by dividing the output voltage of the voltage follower 239 by the resistor R46 and the shadow exposure setting volume 361. Therefore,
By adjusting the main exposure setting volume 360, the light output setting voltage when P (ON) and when P (St-1>) changes proportionally, thereby maintaining a constant relationship between recording density and applied voltage. Therefore, the adjustment becomes simple without requiring the complicated operation of varying and adjusting the set voltages for both P(ON> and P(SH) times as in the past).

FIG. 21 is a detailed circuit diagram of the beam detection circuit 121 and beam detector 346 in FIG. 13.

In FIG. 21, 346 is a beam detector that uses a PIN diode with very fast response. Further, this beam detector 346 is connected to the photoreceptor 301 as shown in FIG.
What is the reference pulse used when writing print data to the printer, and its pulse width and pulse generation position must be extremely accurate.

Therefore, if the pulse width, pulse generation position, etc. vary with each beam scan caused by the rotation of the polygon mirror 313, the writing start point on the photoreceptor 301 will vary, resulting in poor print quality. The anode side of the beam detector 346 is connected through a load resistor R52 and a resistor R55 to one side input terminal of a high-speed comparator 262, which is a comparison means. In addition, resistors R53 and R5 are connected to the G side input terminal of the comparator 262.
A voltage divided by 4 is applied through the resistor R56. Further, a capacitor C12 for noise removal is connected in parallel to the resistor R54. Further, R57 is a positive feedback resistor for providing hysteresis characteristics, and C13 is a feedback capacitor for applying high-speed feedback to improve the output waveform.

In addition, a diode D is connected to the + side input of the comparator 262.
A variable threshold voltage S50 is applied through a 40° resistor R57. This threshold variable voltage 850 is the output of the analog switch 240 or 241 (output of the optical output setting means) (see FIG. 17). FIG. 22 shows the relationship between the one-side terminal input waveform of the comparator 262, that is, the output waveform of the beam detector 346, the →-side terminal voltage of the comparator 262, and the relationship between the output waveform of the comparator 262 at that time. When the laser beam passes over the beam detector 346 at high speed, a pulse current flows from the beam detector (PIN diode), and the waveforms a and b in FIG. 22 are input to one input terminal of the comparator 262. Now comparator 262 +
The voltage of the side input terminal is the threshold variable voltage S50
Assuming that a low voltage VO6 is always applied because VO6 is not applied, the output waveform of the comparator 262 will be the output waveform shown by the dotted line in the case of waveform a, and the output waveform shown by the solid line in the case of waveform A. Here, waveform a shows a waveform when the sensitivity of the photoreceptor 301 is low and the laser output during the main exposure is 6 mW or more, and conversely, a waveform when the sensitivity of the photoreceptor 301 is high and the laser output is 5 mW or less. As can be seen from this output waveform, when the voltage on one side of the comparator 262 is kept constant, the output waveform changes significantly depending on the amount of light incident on the beam detector 346. Therefore,
By using the threshold variable voltage S50, when the light intensity of the laser beam is large, the voltage is corrected to VO5, and when it is small, the voltage is corrected to VO6.
As shown in FIG. 22, the output waveform can be kept almost constant.

FIGS. 23A and 23B are configuration diagrams of the beam detector (PIN diode) 346. Figure 23 (A), (
In B), 410 is a light receiving element, 411 is an electrode wire, 41
2 is a mask plate, 413 is a laser scanning beam, 414 is a light receiving element mounting base, and 415 is an output lead wire. The PIN diode used in this example has a photodetector shape of 2.5x2.5n+m and a response time of 4n5ec.
belongs to.

The laser beam 413 is scanned at a constant speed in the direction of the arrow in FIG. 23<A) by the rotation of the polygon mirror 313. When the laser beam 413 passes over the light receiving element 410, an output current flows according to the optical output of the laser beam 413. At this time, the input waveform of the one side input terminal of the comparator 262 in FIG. 21 becomes the waveform shown in FIG. 24. In FIG. 24, input waveform 1 is a waveform when there is no mask on the light receiving element 410, and noise is generated before and after the output waveform. This is mainly intended for cases where the light receiving element 410 itself is used for detecting light that is originally stationary or for detecting light that has a very slow speed even when it is being scanned, and the parallelism of the end surface of the light receiving element 410 is There are quite a lot of bad elements, and when the laser beam passes through their end faces, the output current becomes unstable. Therefore, in order to solve these problems, a mask 412 that does not allow the laser beam 413 to pass is attached on the light receiving surface of the light receiving element 410 to prevent output waveform cracking when the beam passes on the end surface. The mask 412
As shown in FIG. 23 (A>, (B)), the light receiving element 410
The laser beam 413 has a structure in which a square window is opened in the end face part and the part not including the electrode wire 411 lead-out part.
The light is made to fall on the light receiving element 410 only when it passes through the four corner windows. With such a structure, the accuracy, particularly the parallelism, of the window portion of the mask is increased, so that the input waveform to the comparator 262 can be a waveform that does not contain noise, as shown in input waveform 2 in FIG. 24.

FIG. 25 is a detailed circuit diagram of the print data write control circuit 119 in FIG. 13. The main functions of this print data write control circuit 119 are as follows:
The parallel print data S57 is serially converted so as to fit the print data 857 from No. 2 onto a predetermined area on the photoreceptor 301 according to the size of the paper to be printed, and is sent to the laser modulation circuit 120. In addition, the print data S
A shadow signal for improving print quality is generated from the data contents of 57 and sent to the laser modulation circuit 120 together with the print data. Further, the laser modulation circuit 120 sends out signals necessary for setting the optical output. Further, a timing signal for controlling the output from the print data control section 2 is sent to the interface circuit 122. The other is to generate test printing patterns necessary for maintenance.

In FIG. 25, 186 is an input/output port 187 for sending and receiving signals necessary for control within the laser modulation circuit 120 and the print data writing control circuit 119;
A counter/timer 188 controls the writing position of print data, test pattern generation, laser light output sampling, and the like. 189 is a crystal oscillator that serves as the reference clock for the image clock pulse and has an oscillation frequency of approximately 32M.
It is HZ. Reference numeral 190 is a circuit for generating an image mill, which generates a pulse (approximately 8 MHz) corresponding to one dot, the minimum modulation unit of a laser beam. 191 is a control counter for serially converting the print data in bytes (8 bits) received from the interface circuit; 192 is a circuit that generates a test pattern used during maintenance;
211 is a multiplexer that selects test pattern data and print data from the interface circuit 122; 210 is a shift register that converts the 8-bit parallel data from the multiplexer 211 into serial data;
13 and 214 are line memories for temporarily storing print data, and the memory capacity is 4096 bits; 212 is an address counter for the line memories 213 and 214;
15 is a decoder for generating a signal for controlling the test pattern generating circuit. 226, 227, and 228 are 7 lips and 70 pieces for synchronizing the print data and shadow data sending timings.

The details of the counters 187 and 188 will now be explained. A counter 275 determines the timing for correcting the laser light intensity of the line (horizontal scanning line), and counts based on the reference clock signal S53, and generates a sample signal S75 used for light intensity correction and line start. 276 is a counter for determining the horizontal recording start position, which is counted based on the Q7 output (bidet 1 unit signal) S83 from the control counter 191 and outputs the horizontal recording start position (left margin) signal S84. . A counter 277 determines the recording end position in the horizontal direction, and counts based on the video 8-dot unit signal S83, and outputs a data write end position (write margin) signal 8S85. 278 is a counter for positioning the start of recording in the vertical direction, and counts based on the output of the gate 198 which uses the paper leading edge position (page top) signal S74 outputted from the input/output port 186 and the Q output of the flip-flop 204. The page top count output S76 is generated.

279 is a vertical recording end positioning counter which counts based on the output of the gate 198 as described above and outputs a page end count signal S77. 280
is a vertical test pattern control counter which performs counting based on the Q output of the flip 70 knob 240 and outputs a test pattern control signal 879.

FIG. 26 shows the interface circuit 12 in FIG.
2 is a detailed circuit diagram of No. 2. In FIG. 26, T263 is an input/output port that receives command data and print start command signals from the data control unit 2, and sends status data and ready status signals of the print control unit to the data control unit 2. , 264 is an 8-bit latch for both command and print data.

265 is a transceiver/receiver for the interface data bus S59. 266 is data bus 85
Data selection signal for specifying 9F data = f for s6o
Reference numerals 21-da and 269 indicate BUSY signal control circuits that control the timing of data transmission to the j0'-data control unit 2 when command data and print data are received.

Next, details of the interface signal will be explained. In FIG. 26, 859 is a bidirectional 8-bit data bus, and S60 is a data selection signal on data bus 359.
Data on the data bus S59 is selected by a combination of two signals DC0M and ID5TA. S61 is IPRD
A signal indicating that the print control unit 100 is in a ready state at Y.

862 is IPREQ, a signal that allows the data control unit 2 to send the print start signal IPRNT, S63 is IPE
Upon receiving this signal at ND, the data control section 2 side stops sending out the print data.

S64 is IH3YN, which is a request signal to send one line of print data, S65 is IPRNT, which is a print start command signal, and S65 is IPRNT, which is a print start command signal.
30 is a strobe signal for commands and print data, abbreviated as l5TB, and 866 is IBSY, the strobe signal Q.
This is a signal that permits transmission of S30 and permits reading of status data on the data control unit 2 side.

Commands and print data are sent to transceiver/receiver 26
The status identification signal S68 is output to the output line S72 of 5.
It is output when it is FF. The data on output line S72 is transferred to data latch 264 by strobe signal S30.
latched to. In the case of command data, it is latched to the input/output port 263 and the prescribed operation of the identified command is executed. In the case of print data, it is sent from an output line 859 to the print data write control circuit. Furthermore, the transmission of the status data is carried out as follows. By receiving a status request command on the print control unit 100 side, the status content corresponding to the command is set to the status meter output 871 of the input/output port 263. The set status data S71 is input to the transceiver/receiver 265. The input data is output onto the data bus 359 when the status identification signal 868 is ON.

Details of commands and statuses used in the print control section 100 are shown in FIGS. 27 and 28, respectively.

In FIG. 27, SR1-SR6 are status request commands corresponding to status list 6 in FIG.

PSON is a power save command that reduces the power consumption of the fuser 331, and PSOF is a command to cancel the power save state.When not recording, the power rape command PSON reduces the power consumption of the fuser 331 to save power, and Sometimes power save cancellation command P
The SOF allows the power to be increased to normal values to fix the toner. C3TU is a cassette upper stage paper feed specification command, C3TL is also a lower stage specification command,
VSYNC is a command that instructs the data control unit 2 to start sending print data, MFI~9 are manual feed mode specifying commands, 78M1~4 are top/bottom margin specifying commands that specify the print start position on paper, and SOF is a shadow command. The commands for forcibly turning off exposure are shown below.

In Fig. 28, during paper conveyance, the status indicates that paper is being fed and the paper is being conveyed into the printer, and the select switch ON is the select switch 354 of the operation unit.
The VSYNC request status indicates that the print control unit 100 has received a command to start printing and is now ready to receive print data, and the manual feed status indicates that the paper feed mode is manual feed mode. The status to notify, upper/lower cassette is the status indicating the status of the selected cassette in the cassette feeding mode, and top/bottom margin is the status of the top/bottom margin selected by the top/bottom margin commands (78M1 to 78M4). status, cassette size (
1st row) and cassette size (lower row) indicate the size code of the installed cullet.Test/Maintenance indicates the test/maintenance status.Data resend request requires reprinting due to jam etc. During wait, the status indicates that the printer is in a warm-up state of the fixing unit. During power rape, it indicates that the printer is in power save mode by the power save command (PSON>). Status 4 indicates that an operator call factor has occurred.Serviceman call indicates that a serviceman call factor of status 5 has occurred.Tray full indicates that there are more than the specified number of sheets in the paper output tray. does not indicate that it is full.Toner pack replacement indicates that the toner bag is full of toner.Paper jam indicates that paper has jammed inside the machine.No toner indicates that there is toner in the toner bag. A cover oven indicates that the front door is not closed.A timing error indicates that there was a problem with the transfer of print data.A fuser failure indicates a fuser heater burnout, temperature FtJSE burnout, etc. , indicates that there is an abnormality in the fuser.Laser failure indicates that the laser diode does not reach the specified output or the beam detector cannot detect the beam.Scan motor failure This indicates that the specified rotational speed is not reached even when the specified rotational speed is reached, or that the specified rotational speed deviates from the specified rotational speed for some reason after reaching the specified rotational speed.

Heat roller replacement indicates that the fuser roller counter shown in FIG. 15 has reached a specified value and that the fixing roller needs to be replaced. Drum replacement similarly indicates when the drum replacement counter reaches a specified value and the drum needs to be replaced, and developer replacement similarly indicates when the developer replacement counter reaches a specified value and the developer needs to be replaced. .

FIG. 29 shows the positional relationship between one scanning range of the laser beam including the beam scanning section 349 on the photoreceptor 301 in FIG. 3, and the beam detection position and data writing position that fall within the scanning range. FIG. In FIG. 29, 416 is the beam scanning start point, 417 is the beam scanning end point, and the beam that has reached the beam scanning end point 417 is moved to the next surface from the beam scanning starting point 416 at time O by the next surface of the polygon mirror 313. Begin beam scanning. 418 indicates a beam detection starting point of the beam detector 346, 428 indicates the left end surface of the photosensitive drum, and 429 similarly indicates the right end surface. 419 represents the left end surface of a sheet of paper size A3, and 420 similarly represents the right end surface. 421 represents the left end surface of a sheet of paper size A3, and 420 similarly represents the right end surface. 421 is the same A
The data writing start point 422 also indicates the data writing end point for the three sizes of paper.

423 is the left end surface of the paper size 80, 424 is the right end surface, 425 is the data writing start point of the same size, 426
Similarly, each represents the end point of data writing. Also 42
7 represents the center point of the paper.

d4 is the distance from the beam scan 418 to the A3 size writing start point, d5 is the same < distance to the A6 size writing start point, d6 is the same < distance to the A6 size writing end point 426, d7 is A3 size Each represents the distance to the writing end point. d8 represents the distance from the beam detection point 418 to the right end surface 420 of A3 size paper. Also, d3 represents the range of one scanning of the beam, d14. d9. d10 indicates the effective printing range in A3 and 80, respectively. As is clear from this drawing, the paper feed of this printer is always centered around the paper center point 427, so the starting point for printing from the beam detector position 418 differs depending on the paper size. detector 346
It is necessary to write data after a period of time corresponding to the distance from when the beam is detected to each writing start point. Instead of performing such control, this printer does not employ a paper edge feeding mechanism, so it is possible to print on the entire surface of the paper. In this embodiment, the left and right margins on the left and right sides of the paper are set to 3IllIIl, but they can be set to 0. In addition, conventional printers that perform edge-feeding conveyance usually require a margin of about 8 to 110 l1, which has the disadvantage that a considerable portion of the paper is not printed.

FIG. 30 shows the paper size and print area portion of FIG. 29 not only in the horizontal direction but also over the entire surface of the paper. In FIG. 30, 436 represents A6 paper and 437 represents A3 paper. 419,420°421.422,423,4
As for 24,425,426.427, the same positions as in FIG. 29 are shown. 430 represents the leading edge of the paper, 432 represents the data writing start point in the vertical direction of the paper, 431 represents the trailing edge of the A3 size paper, and 433 represents the data writing end point of the A3 size. 434 represents the trailing edge of the paper of size 0, and 435 represents the end point of writing data of size 6.

Next, the operation of the component device will be explained with reference to the time charts of FIGS. 31 and 32.

Ready signal rPRDYO (861) of print control unit 100
becomes ready for printing.

At the same time, the print start signal IPREQO (862) becomes active. Next, the laser enable signal “LDONI”
(849) rises to '1'. This signal 849 turns on transistor 258 in FIG. At this time, the data flip-flops 226 to 228 in FIG.
is not set, so the print data signal 847 and the shadow signal 34B are both O'. Since the laser enable 849 is '1', the print data is O', and the shadow signal 848 is lOl, the gate 246 in FIG. 17 is established and the analog switch 254 is turned on, causing the laser diode 259 to emit light.

Then, the monitor photodiode 260 operates, the operational amplifier 239 operates via the operational amplifier 232, and the laser ready signal LRDY1 (S43) is generated.

Next, a sample signal SMPTO (S75) is generated from the counter 275 in synchronization with the horizontal synchronization signal H8YO (854). This signal 875 is used to set the time corresponding to the distance d3 (distance of one line) between 416 and 417 in FIG. 29 that defines the paper size. This allows the light amount to be corrected for each line and is used as a line start signal. That is, this signal 875
The gate 193 in FIG. 25 opens, and the gate 194 opens.
A sample signal 845 is generated from the sample signal S
45 turns on the analog switch 236 via the gate 244 in FIG. 17, a correction signal is given to the laser diode 259, and thus light intensity correction is performed for each line. PTCTO (S76) is the counter that determines the leading edge of the paper (page top counter)
The output signal PECTO (S77) is the output signal of a counter (page end counter) that determines the end position of the sheet. When the time comes to write the image, VS
Sends the status of the YNC request to the external device. Due to the stiffness, a VSYNC command is issued, and when it is received, P
TOP (S73) appears and from that point start counting the number of H8YNC lines. In the same way, specify the number of lines to be written from that position (the ending position). A top margin nT and a hot margin OE are provided to allow this specified value to be changed. If the above specification is made, when VSYNC comes, PTOP will start before the leading edge of the paper.
A signal is output. For example, if a 5 mm margin is required, count the number of lines including that margin.

If the top value is 10111111, the corresponding data will be set in the timer. The position of the bottom can be determined in the same way. Once the data is set in the timer, the gate is opened and the count is started, and when the count is finished, it starts up. Gate 201 in FIG. 25 determines where to write in this way. LSTO (S78) is the Q output of flip-flop 204 for synchronization, is set by H3YNC, and is reset when the sample timer signal rises.

This reset line is connected to the LDON signal (349
), and the reset line normally does not work, but is forced to reset. The reset generates the Q output of the flip 70 tube 204, and the clock generation circuit 190 operates to count clocks from 18 oscillators. This clock generation circuit 190 is the oscillator 18
The clock from 9 is divided by 4 and a bit-by-bit signal is output only while the line start signal LST is set. This output becomes two types of signals 882 and 887 with different phases. As a result, synchronization for -lines is achieved. VDATI is the print data signal (S47),
The data is output as serial data by the operation of the P/S conversion shift register 210. That is, the P/S conversion shift register 210 receives the signal 88 from the clock generation circuit 190.
However, when the load signal 388 is not applied, the output 886 is l 01 (no laser writing), and when the load signal 388 is applied, the data D5~
D12 is serially converted and output.

At this time, gates 207 to 209 provide 1 to 8 bits.
It will be loaded every cycle. Here, the generation timing of the load signal will be explained.

When there is a place to actually write, data must be set every time the paper size changes, but the counter that controls this is the left margin counter 276 (Fig. 25).
Data are shown in Figure 29 d 9. dlo) and write margin counter 277 (data is 611.d12 in Figure 29).
). In this case, the set defines the distance between the left and right sides based on the center of the paper. H3YN
When the LST signal (878) is output in synchronization with the C signal, the flip-flop 196 is set, which causes the gate 19 to
8 sparkles and the counter 276 starts counting. In this case, the video clock is not counted bit by bit, but once every 8 bits. When the count output that comes out every 8 bits is set in accordance with the left margin N1m1 and the right margin NRI11, counting is performed in synchronization with the LST signal (S78). Then, it starts up after setting and outputting the count number. Therefore, the gate 201 determines the vertical direction,
Since the gate 199 determines the horizontal direction, writing is performed at the point when both gate outputs become (1, 1). At this timing, the load signal is output, and the data S86 is serially converted from the shift register 210 and sent out.

The line memory out signal, MOT (880), is the output of OR gate 222. This controls which data from the line memories 213 and 214 is to be sent. That is, this sending timing is
Controlled by 03. That is, the output state of the flip-flop 203 changes every time a clock pulse is applied, and the gates 220 and 221 are opened alternately, so that the output DOtJT of the line memory 213 or 214 is alternately read out. line memory 21
The writing timing to 3,214 is also gate 2”17,
218 are opened alternately and controlled. This is done in order to facilitate processing by allowing data to be written and read at the same time when a shadow method, which will be described later, is employed.

Next, LDAONI (381) will be explained with reference to FIG. 43.

In this type of recording device, if the laser is not emitted over the entire surface of the photoreceptor 301 in the axial direction, it can only be used on small-sized paper (B5, A4, etc., such as paper 458 shown in FIG. 43). In many cases, printing is not performed, and as a result, toner and the like do not adhere to the area near both ends that are not used. Further, even in a large size sheet (for example, sheet 461 in FIG. 43), there is an unused area (even in the case of small size sheet 458, the used area is within the shaded area 459). If such an area is provided where toner does not adhere for a long period of time, there is a problem that when the blade scrapes off the adhered toner after recording, the contact resistance of the blade in the unadhered area becomes large and the surface of the photoreceptor is scratched. be. So with this device. As shown in the time chart of FIG. 31, the line data on signal LDAON1 (S81) is generated immediately after printing for one sheet of paper is completed, and the print data signal V DATI is generated within this generation period.
(847) is forcibly applied, and by this operation, lines 460 and 463 spanning the entire axial direction of the photoreceptor as shown in FIG. 43 are written after printing for one sheet of paper is completed. In this case, the line data write timing is set to the data LD immediately before the final stage data LDATn in the data of the line memory out signal LMOT, 1 (S80).
The signal is generated when a predetermined time tx has elapsed from the falling edge of ATn-1. Note that such lines are not necessarily limited to those that are written periodically after each sheet of paper has been printed. You can also set it to write.

Next, with reference to Figures 33 to 36, we will explain in detail the method used to make characters easier to see by adding a shadow to the printed characters (also called the shadow method). .

Determination as to whether or not to generate the shadow signal 848 is made by various gates 220 to 225 which alternately input the data of the line memories 213 and 214, and three flip 70 tabs 2.
26 to 228 and the gate 231 on the output side thereof. Among them, the flip-flop 227 is in the horizontal direction (
The flip-flop 228 contributes to determining a shadow based on a change in level in the vertical direction (line direction), and to determining a shadow based on a change in level in the vertical direction (vertical direction). That is, the serial data to be written from the line memory 213 is read out from the flip 70.
When the knob 226 is set, the data in the previous line direction is in the Noritub flop 227, so for example, when the current data is 0' and the previous data is 1', the shadow signal 848 is output. Ru. Similarly, the data of the previous line and the data of the current line are compared at the gate 223. For example, when the data of the current line is 0 and the data of the previous line at the same horizontal position is 1, the flip 70 knob is set. and a shadow signal is generated. Note that a shadow signal is also generated when both flip 70 tabs 227 and 228 are set. This state is expressed by the shadow out signal 5QLIT1 (S86) and the print data signal V in FIG.
DATI (847), shadow signal 5DAT1 (S
48).

FIG. 33 shows a conventional development pattern when the shadow method is not used, and FIG. 34 shows a development pattern when the shadow method is used. In this way, when the characters ``J'' are printed, a shadow is added to FIG. 32, making it very easy to see.

FIG. 36 is a characteristic diagram PA that intersects vertical line S1 and horizontal line S2 and shows the relationship between exposure position and exposure energy in the upper right area of the figure.
TI and PAT2 are shown in the upper left area of the figure as a characteristic diagram Q showing the relationship between the surface potential of the photoreceptor and the exposure energy, and in the lower left area of the figure as characteristic diagrams R1 and R2 showing the relationship between the exposure position and the surface potential, respectively. be. In this figure, among the characters in Figs. 33 and 34, "8" in the X direction and [14] in the Y direction.
-21J is extracted. As shown in the figure, the third
The characteristics PAT1 and R1 of the pattern shown in FIG. 3 are different from the characteristics PAT2 and R2 of the pattern shown in FIG. In particular, regarding the development characteristics, at a certain development level L, the width D1 of R1 in FIG.
It can be seen that the width D2 of R2 in the figure is larger. FIG. 35 is a characteristic diagram showing the relationship between the exposure position and the exposure energy, where the energy of P(ON) during laser irradiation is, for example, 6iw, and the energy of P(SH) when creating a shadow portion is, for example, 4n+w.

The above shadow method can be summarized as follows.

In a device that records recording information (character information, etc.) on a recording photoreceptor by beam scanning in accordance with differences in beam intensity, serial binary input data is transferred to beams having first and second intensities (the P (ON) and P(OFF)), and when the input data has a specific relationship, the first or second intensity intermediate beam is replaced with the first or second intensity beam. Recording is performed using a beam of a third intensity (halftone) located at the horizontal line. It is determined that the binary data changes from significant recorded data (data for forming characters) to unintentionally recorded data (data that does not contribute to character formation), and the unintentionally recorded data part immediately after the change is determined. (b) Compare the data of the current line in the horizontal line with the data of the previous line in the vertical direction corresponding to that position, and as in (a) above, When changing from recorded data to unintentionally recorded data, the unintentionally recorded portion immediately after the change is scanned with a beam of a third intensity.

Note that the shadow described above is added. In this case, this method may be adopted regardless of the type of recorded information (for example, text information or image information), but it is preferable to use this method only when handling text information. In this case, as shown in the flowchart (△) in Figure 55, the microprocessor
If it is text information, it will move to the Shadow JON flow, and if it is non-text information (e.g. image information), it will automatically do so by disabling "Shadow". That's what I do. The command in this case is rsONF shadow 0N10F shown in Figure 27.
It is FJ. Or panel part 2 [Shadow 0N10
．． An FFJ switch may be provided so that the operator can arbitrarily select it.

If the above-described shadow method is used, if the recorded information is character information, a "shadow" can be added, so that the printing quality can be improved. In particular, when recording with a high-density beam, the line "
Since "fading" can be prevented and, as a result, the printing density of one dot line is increased, the printing quality can be improved even for a high-dot Kanji font such as a 40x40 dot configuration. Furthermore, since the permissible range of the vertical deflection of the beam on the photoreceptor due to the "plane deflection" of the polygon mirror can be widened, the polygon mirror can be easily processed and has the advantage of being inexpensive.

In addition to character information, the shadow may also be applied to simple graphic information.

Next, regarding charge correction, FIGS. 37 to 41 and 56
This will be explained with reference to the flowchart shown in the figure.

FIG. 37 shows an example of the configuration in the charging high voltage power supply circuit 160, which is a configuration example of the high voltage power supply 0N10FF signal 8.
35, a voltage control circuit 445 whose operation is controlled by the voltage control circuit 445, a step-up transformer 446 which applies a frequency output to the primary side and generates a high-voltage output from the secondary side, and a step-up transformer 446 which rectifies the output of the step-up transformer 446. a high-voltage rectifier circuit 447 that applies a rectified output to the charging charger 304; a current/voltage conversion circuit 450 that inputs the current flowing to the charging charge +7304 and converts it into a voltage; and an output of this current/voltage conversion circuit 450. The operational amplifier 449 has one input as the control reference voltage generating circuit 448 and the output of the control reference voltage generating circuit 448 as the other input. The control reference voltage generation circuit 448 receives an analog control signal 836.
It is controlled by and outputs different control reference voltages. According to such a configuration, the output frequency of the voltage control circuit 445 is determined based on the output from the control reference voltage generation circuit 448, and a high voltage output horn is generated based on this, and the current of the current charging charger is is applied to the current/voltage conversion circuit 450, this output voltage and a reference voltage are compared by the operational amplifier 449, and a control operation is performed so that the two match, so that the output applied voltage can be stabilized.

Here, the contents of the analog control signal 836 will be explained in detail.

As shown in FIG. 38, the photoreceptor 301 has a characteristic that its surface potential changes significantly with temperature changes.

In the figure, the horizontal axis represents temperature, and the vertical axis represents surface potential change ΔVO.
This shows the type of drum: 451°452.45
Each type has different characteristics. Also, the 39th
The figure shows each drum 451,452.45 at a temperature of 25℃.
3 shows a characteristic diagram showing the relationship between the drum inflow current ID and the surface potential vO of No. 3, which is a proportional straight line. Therefore, in order to keep the surface potential constant, it is sufficient to change the drum inflow current ID. For example, in order to maintain a surface potential of 800V for the drum with characteristic 451 in FIG. Inflow current change amount △ID- corresponding to 'O
(Various characteristic data of the photoreceptor is stored in the RAM 107). Here, since the inflow current ID and the output current have a corresponding relationship as shown in FIG.
Analog signal (input voltage) S to reference voltage generation circuit 44
By changing 36 to 2V, 4V, and 6V, the inflow current ID can be adjusted. Figure 41 shows the analog input current (D/A converter 16 in Figure 15).
For example, the temperature of the drum 301 can be detected by the temperature sensor 342 (thermistor shown in FIG. 14), and the analog control signal S36 can be applied in response to the temperature change. Bye.

The charging correction is performed based on the above contents, and its operation will be explained based on FIG. 56. 14th
When the thermistor 342 shown in the figure detects the temperature of the drum, the A/D converter 271 converts it into a digital signal, and when the data conversion is completed, the temperature data DTn and the temperature 25
A value D△T is read by subtracting the temperature data DT25 of the drum' at ℃. Next, the reference data DV at a temperature of 25℃
25 is read, DV25+DΔV is calculated, and the calculation result DVn is output to the D/A converter 165. Then, by referring to the RAM 107, the drum characteristic data at address r6000J shown in FIG.
0 and further read the feedback error data DΔV. Next, read the reference data DV25 at a temperature of 25°C, calculate DV25+D△■, and the calculation result DVn
is output to the D/A converter 165. Then, Vn is applied to the analog input of the charging high voltage power supply 160 (836
) and the control input signal S35 of the charging high-voltage power supply 160 is turned on to perform the correction. The above correction is repeated every time the temperature changes to keep the surface potential of the drum constant.

Note that the characteristics of the various photoreceptors (drums) stored in the nonvolatile RAM 107 can be specified by the operator from the outside. That is, as shown in the flowchart ① in FIG. 60, when it is determined whether or not to replace the drum,
If the drum is to be replaced, the drum characteristic number is set and the test key is turned on, after which the drum characteristic number is written in the drum characteristic number area of the non-volatile RAM 107. Therefore, the characteristics of the currently used drum are always selected and corrections are made based on this.

When the charge correction described above is performed, the charge potential of the photoconductor is kept constant even if the temperature of the photoconductor changes due to changes in the external environment or temperature rise in the gas, so the charge potential based on temperature changes can be adjusted. It is possible to prevent the occurrence of problems such as fogging due to a decrease in the printing rate, a decrease in printing rate, or an increase in the charged potential, and it is possible to always provide clear printing. Furthermore, in this embodiment, by inputting (external setting) information classifying the density characteristics of the photoconductor, corrections are made accordingly, making it possible to perform temperature correction of charging characteristics with extremely high accuracy. , it is possible to alleviate variations in the temperature characteristics of the photoreceptor itself, and there is also the advantage that the range of specifications for the photoreceptor can be expanded.

Next, the flowcharts shown in FIGS. 47 to 56 and the flowcharts shown in FIGS.
The operation of the entire apparatus will be explained with reference to the time charts shown in FIGS.

After the power is turned on, the door switch 129 is turned off.

It is confirmed that the paper ejection switch 336 is OFF, the manual stop switch 328 is OFF, the pass sensor 123 is OFF, the temperature fuse 130 is not disconnected, and the paper ejection tray 384 is not full (FULL). The test print mode, maintenance mode, and exchange mode are checked.If there are no problems, the MC
The relay 131 is turned on, and the fuser heater lamp 33
3ON, scan motor 312 turns ON and timer A
(TIMA) starts. When the timer ATIMA counts a predetermined time t1, mechanical parts such as the drum motor and the developer motor are turned on, and when the timer ATIMA counts a predetermined time t2, the laser 344 is turned on.

When time t25 is counted by TIMA, it is determined whether the laser is ready or not, and if yes (Y), then T
IMA-[26 is 31 o'clock and the transfer charger, laser, developer motor, and developer sleeve bias are all O.
The drum motor, heat roller motor, static elimination lamp, and pre-transfer static elimination lamp are turned OFF when the time TIMA=t27 has elapsed. Then TIMA=t 29
Scan motor ready at the timing of 1-ISYNC
It is determined whether the device is ready, and if the answer is yes (Y), TIMA is stopped (see Figure 47).

Next, a determination is made as to whether it is a “treyful in status 4”,
It is determined whether "toner pack replacement" is required, and whether or not there is "toner out". If the tray is full, the "tray full" flag is set to "0" after paper is removed from the paper output tray, and the paper output tray counter is set to "0". "If the toner bag is replaced, the reset will be performed when the state returns to its original state, and in the case of toner replenishment, the reset will be performed once the state is restored. After passing through the above flow, the next status will be 1. If it is NO (N), then it is determined whether “Paper is out” in “Status 4”, and if YES (Y), it is determined whether or not “Power saving” is in progress. Paper out detection ON
It is determined whether the status is J or not. If NO (N), the ``out of paper'' flag is set to O', and if the ``fixer is ready'', the ``status waiting'' flag is set to ``0''. Next, IPRDYO
N, IPREQON, and it is determined whether "power saving" is in progress or "out of paper", and if there is no problem, r TMA starts. When TIMA=toi, the registration motor 149 rotates in reverse, and when IMA=t02, the registration motor 149 stops. At this stage, the leading edge of the paper is held between the paper feed rollers.

Next, it is determined whether it is manual feed J or not, and if no (N), it is determined whether rlPRNT ONJ or not, and yes (Y).
If so, it becomes rIPREQ 0FFJ. Next, it is determined whether or not the timer E (TIME) is in operation, and if it is in operation, it is determined that rTIME=t3O, and if YES (Y), TIME is stopped and the transfer shutter 3o5. Peeling 13It (Peeling) Charge r306. Developer motor 1
41. Each of the fixing device motors 143 is turned on. rT
If IME=t 30J, TIME stops and the flow shifts to O (see Figure 48).

Next, TJMA starts and plaid solenoid 158
turns on, rtIMA=t IJ, developer motor 1
41. Static elimination lamp 302. Pre-transfer snow removal lamp 303. Each of the drum motors 147 is turned on. rl-IMA
- Transfer charger 305 at t2J. Fuser motor 143
becomes ON.

At rTIMA=t 3J, the power charger 306 is turned on.
Then, when rTIMA=t4J, 4A is restarted from O' to T■. Next, whether it is "manual feed" or not.
The upper and lower cassettes are determined, and if the cassette is the upper cassette, the paper feed motor 151 is rotated forward to feed the upper cassette, and if the cassette is the lower cassette, r
After waiting until TIMA=t5J, the paper feed motor 151 is reversed to perform lower paper feeding. Next, turn on the laser 344 when rTIMA=t5J, and turn on the laser 344 when rTIMA=t6J.
At this time, the charger 304 is turned on.

rTIMA=t 7J checks whether it is laser ready or not, and if yes (Y), rV in "Status 1"
SYNC request" flag is set to 1'. After that, timer B (D-IMB) is started and the flow shifts to ◎ (Fig. 49).

Next, the paper feed motor 151 is stopped at rTIMA=31J,
rVsYNc command reception J is determined and yes (Y)
If so, it is determined whether or not rTIMB<t32J, and if yes (Y), TIMB is stopped, the "page top" and "page end counter" counts are started, and image writing processing is performed. Timer C, D (TIMC,
D), start TIM at rTIMA=t 34J
A stop, paper feed motor 151 is stopped. Then rTI
When Mc/D=t35J, the registration motor 149 rotates forward, the total counter 354 turns on, and rTIMc/D-t36
Use J to determine whether the toner concentration is high or low. If the density is low, the toner supply motor 159 is turned on.

1st page end interrupt-1 is determined, yes (Y)
If so, an image writing end IPEND pulse is output.

Add 1 to the customer service counter, and say "Trayful", [Drum replacement], and "Developer replacement".

If the heat roller is replaced, each status will be displayed.The determination result of "receiving the rVsYNc command" is as follows.
If no (N), the charge derailer 304 is turned off when rTIMB=t46, and the laser 3 is turned off when rTIMB=t47J.
44. Break charger 304 OFF, rTIMB=t
47J and laser 344. Hatari Charger 306. The developer motor 141 is set to oEE and rTIMI3=t, respectively.
Transfer charger 305.48J. Turn off the fuser motors 143 and turn off the drum motors 147.rTIMB=t49J. Static elimination lamp 302. Pre-transfer static elimination lamp 303
are turned OFF, respectively, and rTIMB=t 50'', the plaid solenoid 158 is turned OFF.

Moreover, in the flow of IT IMB<t 32j, −(N
>, then it is determined whether rTIMB<t33J, and if no (N), TIMB is stopped and TIMΔ is started. After that, turn on the plaid solenoid 158, and
TIMA=t At the IJ stage, the developer motor 141. Drum motor 147. Static elimination lamp 302. The pre-transfer static elimination lamps 303 are each turned on. and rTIMA=t
2J, the transfer charger 305. Fuser motor 143
is turned on, and when rTIMA=t3J, the group charger 306 is turned on. Next, it is determined whether rTIMA=t4J or not, and timer A is temporarily stopped and restarted. The developer motor 141. Transfer charger 305. Hakuli Charger 306. Each of the fixing device motors 143 is turned on. rTIMA=t5
At J, the laser 344 is ON, rTIM=-t At 6J, the charging charge is turned on at t304, rTIMA=t At 7J, it is determined whether or not the laser is ready, and if yes (Y), the TI
MA is stopped (see Figure 50 above).

Next, it is determined whether or not the toner full detection switch 126JON is on, and if it is ON, a display is performed, and if it is not, it is determined whether or not the toner out detection switch 125JON is on, and a display is performed. Next, a judgment is made as to whether or not it is manual feed. Set it to 1'. Next, timer F (TIME
). 5 if the stop flag is 1'
Set TPF to O' and print ready IPRDY to OF.
F Ic'l. 5 If TPF is not 1, a determination is made as to whether it is manual feed 1J or not, and if it is manual feed 1, T
IMF stop, manual stop switch 328O
It is determined whether the FF, manual feed O', 71MB stop, cassette paper out detection switch is ON or not, and then the print request ■PREQ is turned ON, and the flow shifts to ■ in FIG. ).

Next, the contents of the timer interrupt in each flow will be explained with reference to FIGS. 52 and 53.

This determines whether or not each of the timers A, B, C, D, and E is in operation, and counts up when each one is in operation. Read all input information in the port input reading part. Then, the timer is stopped at rTIMO/D=t 38J, and it is determined whether or not rTIME=t 39J. From then on, the operation of timer E (TIME) is continued, and at each time "toner replenishment motor 159J, r registration motor 149" is stopped. Then rTIME
-t4" and then determines whether "rTIMA is in operation" (
This is to determine whether the next sheet of paper will be printed). If TIMEA is in operation, TIME is stopped. After that, the charger 304 is turned off at [T11vlE=t41J.

rTIME=t 42J and Ray V-344, ha'y'
) Charger 306. Turn each developer motor 141 to O.
FF. rTIME=t 43J transfer charger 305. Turn off the fuser motor 143 and turn off the rTI.
ME=t 44J, drum motor 147, static elimination lamp 3
02. The pre-transfer static elimination lamps 303 are each turned off (see FIG. 52).

Plaid solenoid 158OF with "TIME-145"
F, TIME stop, determination of whether "Fuser temperature is normal", "F Fuser temperature Fucose stage", "Scan motor 3
"Is the door switch 129 ready?" and "Is the door switch 129 OFF?" are determined, and various processes are performed depending on each state.

Next, the contents of the command interruption in each flow will be explained with reference to FIG. 54. When command interrupt processing is started, it is determined whether there is a "parity error" or not. If it is an error, the flag of the status DATA81J becomes 1' and becomes an illegal command error 1. If it is not a “parity error”, the [status request] is SR1~
6, and if it is within the range, an output corresponding to one of them is generated. If none of the [Status Requests] apply, it is determined whether it is the "Top Dowel Rim Margin" or not, and if so, the [Top/Bottom Margin] is specified and the "Status Set" is set to 1'.
Then, any one of rDATA21 to rDATA11 is specified. If it is not [Top/Bottom Margin], it is determined whether or not it is "manual feed designation", and if yes (Y), manual feed display and paper size display are performed next, and the paper size register is set. Then, with the manual feed status set, the status becomes 1 and the rDATA41J flag becomes 1'.
Next, in status 4, the process moves to a flow in which the paper out flag becomes 0°. If it is not "manual feed specification", it is determined whether or not it is "cassette specification", and if "cassette specification J" is selected,
The lower display paper size is displayed, the paper size register is set, the manual feed status is reset, the status becomes 1, the DTA41 flag is 0', it is determined whether there is no paper in the cassette, and if there is no paper, the flag becomes '1'. . "
If the cassette is not specified, the select lamp lights up.
It is determined whether or not the online select lamp (specified by an external device, for example, the host side) is lit. If yes (Y), the select lamp is lit, and if the select lamp is not lit, It is determined whether or not the select lamp is off. If YES, the select lamp is turned off, and if )-(N), the process moves to the next flow.

Next, the flowcharts shown in FIGS. 55(A) to 55(C) will be explained.

In addition to the above-mentioned "shadow method", "power save" is included in FIG.

The fuser is controlled to the power save temperature and set to [Status 3 power save flag 1], and when power save is canceled, the scan motor 312 is turned ON, the fuser is controlled to the normal temperature, and the "Status 3 power save flag is set to O".
”, and if it is “Start image data transfer”, it is shown in Figure 55 (B
), the process moves to the flow of (C).

The paper size register is read, the top margin table data (Dl) of the specified paper size is read,
It is determined whether the top/bottom margin designation is 5mIR or not, and if the result is NO (N), the top/bottom margin change table data D2 is read. Next, the top margin table data D1 + margin change table data D2 are calculated, and the contents of the top margin adjustment switch (4422 in FIG. 14) are read. Next, the top margin adjustment table data D3 corresponding to the switch is read. Then, the margin adjustment table data D3 is added to and subtracted from the values of Dl and (DI+D2), and the calculation result D4 is set in the page top counter 278.

And bottom margin table data D for the specified paper size
5 is read and the top/bottom margin designation is 5mm.
If it is NO (N), the top/bottom margin change table data D2 is read, the bottom margin table data D5 and the margin change table data D2 are subtracted, and the top margin adjustment switch is The contents of 442 are read, and the top margin adjustment table data D3 corresponding to the switch is read. Next, the margin adjustment table data D3 is added to or subtracted from the value of D5 or (D5-D2), and the calculation result D4 is set in the page counter 279. Next, the light margin table data D7 for the specified paper size is read, and a cassette/manual feed is determined. If the cassette is selected, it is determined whether it is the upper stage (reference) or not, and if it is not the upper stage, it is the lower stage. /Read the lower adjustment table data D8. Add or subtract the above D8 to the value of the above D7, and the calculation result D9 or the above D7
is set in the write margin counter 277. If manual feed is specified, read the contents of the cassette/manual feed adjustment switch (440 in Figure 14), read the cassette/manual feed adjustment table data DIO corresponding to the switch, and then set the adjustment table data to the value of D7. DIO is added or subtracted, and the calculation result D11 is set in the write margin counter 277.

Next, the left margin table data I' for the specified paper size
) 12 is read, a cassette/manual feed is determined, and if it is a cassette, it is determined whether it is in the upper stage (reference) or not. The contents are read, and the cassette upper/lower adjustment table data D8 corresponding to the switch is read. Adding and subtracting the data D8 to the value of the D12,
The calculation result D13 or the data DI2 is set in the left margin counter 276. In the case of manual feed, the contents of the cassette/manual feed adjustment switch 441 are read, the cassette/manual feed adjustment table data DIO corresponding to the switch is read, and the data D10 and the data D are read.
12 is performed, and the calculation result D14 is set in the left margin counter 276.

The details of the cassette paper printing during the aforementioned flow are shown in the time chart of FIG. 57.

When the print start signal [PRNTφ (S65) is output, the print start permission signal IPREQφ (S62) rises. After that, the developing device motor 141 etc. are turned on, and from time 14 to t
8, the paper feed motor 151 operates to convey the paper in the cassette. At this time, the laser diode 344 is turned on at time t5, and data writing starts from time t7 (the diagonally shaded period from time t7 to t1'l is the data writing period). At time t9, the registration motor 149 rotates, and the data written on the photoreceptor is transferred to the paper. Data writing is performed until time t11 when IPRFQφ (862) falls, and after time t11 elapses, the registration motor 149 continues to rotate until time t12 and stops. The laser diode 344 is turned off at time t14.

FIGS. 58 and 59 are time charts for explaining the operation of printing on manual paper. In the following explanation, the differences from the case of printing on cassette paper described above will be explained.

In FIGS. 58 and 59, the paper feed motor 151 is not used, and the registration motor 149 is rotated in reverse to drive the paper feed roller, and is used for paper conveyance, and the registration roller is driven by forward rotation. ing. Also, after receiving the ``1 manual feed command'' for both parties, the print start command [PREQ
φ(362) is made to rise. FIG. 58 shows a case where paper is set in the manual feed guide before the "manual feed command" is generated, and when the manual feed switch 326 is turned on by setting the paper, thereafter at time tO1
After that, the registration motor 149 rotates slightly in the opposite direction and stops with the leading edge of the paper added, and the ``1 manual feed command'' is issued.
At the time when PREQφ (862) rises, the registration motor rotates in the reverse direction again to transport the paper to the transfer position and then stops. Therefore, it is possible to print on paper from the cassette before issuing the "manual feed command".

In the case shown in FIG. 59, the paper is set in the manual guide and the manual field switch 326 is turned ON after the "1 manual feed command is issued first." In this case, the registration motor 149 is is continuously rotated in reverse to convey it to the transfer position. In both cases, the manual stop switch 328 is OFF.
Time t2 after a predetermined period has passed since F (time t 20)
1, the registration motor 149 is stopped, so that a "jam" will not occur even if the paper set in the manual feed guide is longer than the displayed size. In the case of cassette paper, such consideration is not necessary since the size is specified. Therefore, even if the cassette paper runs out, printing can be performed by preparing paper of a size larger than the size of the information to be printed, and it is also possible to use paper of a size that is not in the standard. usage will increase.

Flow (2) is a transition from the flow shown in FIG. 47 above.

The contents of (1) and (2) will be explained with reference to FIG.

When the test print mode is selected, the flow shifts to (2), and the print specified by the print mode No. is executed via the test key. When the maintenance mode is selected, the flow moves to ■, and the maintenance mode operation of No. specified via the test key is executed.
After the replacement mode is selected, the process moves to step 2, where it is determined whether to replace the drum, whether to replace the developer, or whether to replace P1 to rollers, and select the drum characteristic number set, respectively.
With "Developer Replacement No. Set" and "Heat Roller No. Set", predetermined data is processed in the non-volatile RAM 107 via the test key.

FIG. 61 to FIG. 63 are correspondence diagrams showing correspondence between display numbers and respective contents.

(The following is a blank space) [Effects of the Invention] As detailed above, according to the present invention, a first current drive means for low frequency as a current drive means for a semiconductor laser;
It is possible to reduce the power loss in the second current driving means by providing a second current driving means for high frequency and allowing the first current driving means to take charge of approximately 1/2 of the driving current of the semiconductor laser. can. Therefore, even if a low power transistor is used as the second current driving means, sufficient modulation operation can be performed.

Furthermore, since the driving current of the second current driving means can be reduced, the response can be improved compared to the case where modulation is performed using one single transistor, and it is possible to control the optical output minutely.

Margin below

[Brief explanation of drawings]

FIG. 1 is a system block diagram showing the relationship between the device according to the present invention and external devices, FIG. 2 is a schematic sectional view of the print control unit (printer) in the system diagram, and FIG. A schematic perspective view showing the relationship between the laser scanner unit l~ and the recording photoreceptor, FIG. 4 is a schematic diagram showing the paper feeding section in FIG. 2, and FIG. 5 is an example of the paper ejection section in FIG. 2. 6 is a plan view showing the operation panel section of the device of the present invention, FIG. 7 is an enlarged plan view of the display section in FIG. 6, and FIG. 8 is an enlarged plan view of the data control section in FIG. 1. A block diagram showing an example, and FIGS. 9, 10, and 12 are respectively format diagrams of data handled by the data control unit.
The figure shows the correspondence between the area of the recording section in the data control section and the paper.
Figure 13 is a block diagram of the print control section shown in Figure 1, Figure 14 is a detailed circuit diagram of each detector in Figure 13, and Figure 14 is a detailed circuit diagram of each detector in Figure 1.
Figure 5 is a block diagram showing details of the drive circuit and output element in Figure 13, Figure 16 is a circuit diagram showing details of the motor drive circuit and laser scan motor in Figure 13, and Figure 17 is a block diagram showing details of the motor drive circuit and laser scan motor in Figure 13. (Detailed circuit diagram showing the laser modulation circuit and semiconductor laser; Figures 18 and 19 are characteristic diagrams showing the relationship between the semiconductor laser and optical output; Figure 20 is for explaining the operation of the circuit in Figure 17. time chart,
FIG. 21 is a detailed circuit diagram showing the beam detection circuit and beam detector in FIG. 13, and FIGS.
Waveform diagram for explaining the operation of the circuit in the figure, Figure 23 (△),
(B) is a front view showing an example of the structure of the beam detector;
25 is a detailed circuit diagram of the print data write control circuit shown in FIG. 13, FIG. 26 is a circuit diagram of the interface circuit in FIG. 13, and FIG. 27 is a detailed circuit diagram of the print data write control circuit shown in FIG. FIG. 28 is an explanatory diagram showing the contents of the data data used in the device of the present invention, and FIG. 29 is a diagram showing the relationship between abbreviations and functions, and FIG. Relationship diagram, Figure 30 is the second
Figure 9 is a plan view showing the print area of the entire surface of the paper including the paper size, Figures 31 and 32 are time charts for explaining the operation of the circuit in Figure 25, and Figures 33 and 34.
The figure shows the print pattern printed on the paper, and Figures 35 and 36 show the relationship between the exposure position, exposure energy, surface potential, exposure energy, and exposure position to explain the exposure control operation in the circuit of Figure 25. FIG. 37 is a detailed block diagram of the charging high-voltage power supply in FIG. 15, FIGS. 38 to 41 are characteristic diagrams for explaining the operation of the circuit in FIG. 37, and FIG. A schematic diagram showing the relationship between the laser scanner unit and the recording photoreceptor in FIG.
FIG. 43 is an explanatory diagram showing the relationship between the recording photoreceptor and paper, and FIG. 44 is a modification of the paper ejection tray shown in FIG.
5 (A), (B) and 46 are detailed diagrams of the data recorded in each recording device in FIG. 13, a flowchart for explaining the data, and FIGS. 57 to 59 show the operation of the apparatus of the present invention. Time charts for explanation, Figures 61 to 63
The figure is a relationship diagram showing display numbers and their contents in the device of the present invention. 257...first current driving means, 258...
. . . second current driving means, 344 . . . semiconductor laser. 153°゛') SEμI〃B.42 Figure 43 bJ

Claims (1)

[Claims] A first current drive means, which is included in the laser light modulation circuit J3 that modulates the laser light by controlling the current supplied to the semiconductor laser, causes the semiconductor laser to cause optical oscillation and causes a current below a threshold current to flow through the semiconductor laser; It has a second current driving means connected in parallel with the first current driving means, and when modulating laser light, the first current driving means is constantly driven and the second current driving means is constantly driven. Drive means 0N1
A laser light modulation circuit characterized by 0FF control.