JPS60233613A - Beam scanning device - Google Patents

Abstract

PURPOSE:To confirm whether a scanning beam is irradiated or not by providing a beam detector, reflecting mirror, etc., where the scanning beam traveling outside a specific range is passed. CONSTITUTION:Part of the laser beam within a beam scanning range 345 is guided to a beam detector 346 through a reflecting mirror 345. Therefore, a beam detector 346 detects the scanning laser beam in every horizontal scan by one surface of a mirror 313. Further, the remainder of said beam within the scanning range 348 mirror which is not incident on the mirror 345 illuminated the photosensitive body 301. In this case, the beam passed through the lens 314 does not illuminates the photosensitive body directly, but be reflected by reflecting mirrors 315 and 316 and guided to the photosensitive body. Then, the mirror 345 is fitted on a support member 456 placed outside the beam incident area through a leaf spring with a screw 455, and a fine adjusting screw 457 is provided under this spring 454 to vary the angle of the mirror 345.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a beam-type scanning device that scans a photoreceptor, which is a recording medium, with a beam and records information on the recording photoreceptor. The purpose is to make it possible to confirm whether or not this is occurring.

[Technical background of the invention and its problems] For example, a charged recording photoreceptor is scanned with a laser beam to record information on the recording photoreceptor, the recorded latent image is developed, and the developed information is A beam-type scanning device has been developed that transfers toner onto paper and fixes the transferred toner on the paper using heat. In such a scanning device, the laser beam that scans the recording photoreceptor to record information may harm the visual organs if viewed directly, so the laser beam must not leak outside from the area where the laser beam is scanned. It is necessary to shield it. but,
On the other hand, in order to be able to confirm whether or not the recording apparatus is recording normally, it is necessary to be able to confirm whether or not the scanning laser beam is properly incident on the recording photoreceptor. However, there was nothing that met the demands of both parties.

[Object of the Invention] An object of the present invention is to provide a beam-type scanning device that can confirm whether or not a scanning beam is irradiated without using expensive equipment.

[Summary of the Invention] The configuration of the present invention to achieve the above object is that in a device that scans a predetermined range with a beam, a means for guiding the beam outside the predetermined range and detecting it is provided, and an output of the detection means is provided. is displayed on the surface of the scanning panel based on the

(The following is a margin) [Embodiment of the Invention] Hereinafter, a description will be given with reference to an illustrated embodiment to which the present invention is applied.

FIG. 1 is a block diagram of a system for recording information on a recording medium by a laser 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 100 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 IIIR diagram of a printer 300 having a video interface, and the printer 300 incorporates the print control unit 100 shown in FIG.

In FIG. 2, 300 is the printer body, 301 is
photoreceptor for recording information by laser beam,
Reference numeral 302 denotes a snow removal lamp for removing the electric charge from the photoreceptor 301 to an initial state, and is composed of a plurality of 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 charger for uniformly charging the photoreceptor 301 to a predetermined potential; 305 is the photoreceptor 301;
A transfer charger 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 developing device for developing the electrostatic latent image written on the photoreceptor 301 by a laser beam;
08 is a component of the developing device 307, and is a magnet roller for attaching the toner to the electrostatic latent image on the photoreceptor 301, which rotates in the direction of the arrow.

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

311 is the video data input from the data control unit,
A laser scanner unit 312 scans and modulates a laser beam onto the photoreceptor 301 for recording.
01, an octahedral polygon mirror 313 for rotating the polygon mirror 312 at high speed;
A scan motor 314 is an f/θ lens for keeping the scanning speed of the laser beam on the photoreceptor 301 constant. 315 and 316 are the scanner units 31;
This is a reflecting mirror for guiding the laser beam from one side to the photoreceptor 301.

317 is an upper cassette that can hold 500 sheets of paper.
318 is an upper paper feed roller for taking out sheets of paper one by one from the upper cassette 317; 319 is an upper paper out switch that detects when there is no paper in the upper cassette 317; 320 is an upper power set 317; This is an upper cassette size detection switch consisting of 4 bits for detecting a size identification mark. 321 is a lower paper feed roller, 323 is a lower paper out switch, 324
indicate the lower cassette size detection switch. In addition, the upper section can store 250 sheets of paper from the lower section, and can also be used with cassettes.

325 is a manual feed switch that detects the paper inserted from the manual feed guide 326; 327 is a manual paper feed roller that conveys the paper after the insertion is confirmed by the manual feed switch 325; 32
Reference numeral 8 denotes a manual stop switch that detects the paper conveyed by the manual paper feed roller 327.

Reference numeral 329 denotes a registration roller for synchronizing the image developed on the photoreceptor 301 and the paper.

330 is a conveyor belt for conveying the paper separated by the peeling charger 306 to a fixing device; 331 is a fixing device for fixing the toner on the transferred paper;
332 is a fixing roller, 333 is a heater lamp for heating the fixing roller, 334 is a screwdriver for detecting the surface temperature of the fixing roller, 335 is a discharge roller, and 336 is paper discharged from the fixing device 331. This is a paper ejection switch for detecting paper that has been removed.

337 is a cooling fan for cooling the inside of the printer 300, and 338 is the charger 304 and the transfer charger 305. A high-voltage transformer that generates high voltages to be applied to the peeling charger 306, the developing device, and the magnet roller 308, respectively.

339 is a power supply device that generates DC voltages used for each control, and 340 is a PC board unit that controls the printer 300.

342 is a photoconductor 301 provided near the photoconductor 301;
A thermistor with extremely low thermal resistance is used in the drum temperature sensor to detect the temperature of the drum.

FIG. 3 is a perspective view schematically showing a portion for recording information on the photoreceptor 301 using a laser beam. In FIG. 3, a laser beam emitted from a semiconductor laser 344 is corrected into parallel light by a collimator lens 343, and the parallel light is applied to one surface of an octahedron of a polygon mirror 313. Since the polygon mirror 313 is rotated at high speed in the direction of the arrow by the scan motor 312, the laser beam incident on the polygon mirror
The beam scans the beam scanning range 3 through the f/θ lens 314.
48 ranges are scanned from left to right. A part of the laser beam within the beam scanning range 348 is reflected by the reflecting mirror 3.
45 to a beam detector 346. Therefore, each time one horizontal scan by one surface of the polygon mirror 313 is performed, the beam detector 346 detects the laser beam being scanned. Further, the laser beam that is not incident on the reflection mirror 345 within the beam scanning range 348 is irradiated onto the photoreceptor 301 . In FIG. 3, the location where the laser beam is scanned on the photoreceptor 301 is shown at 349. 30
4 represents an electrostatic charger, and 347 represents a sheet of paper. Incidentally, as shown in Fig. 2, the actual printer has an f/θ lens 3.
14 is not directly irradiated onto the photoconductor 301, but is guided to the photoconductor 310 by being reflected by reflection mirrors 315 and 316; however, for convenience in FIG.
6 is not shown in the figure, and the laser beam that has passed through the θ lens 314 is directly irradiated onto the photoreceptor 301.

Here, the configuration of the reflecting mirror 345 will be explained with reference to FIG. 42. As shown in the figure, this reflecting mirror 345 is attached to a support member 456 located outside the beam incidence area with a screw 455 via a plate spring 454, and a fine adjustment screw 457 is attached to the bottom of the plate spring 454.
is provided so that the angle of the reflecting mirror 345 can be changed.

As is clear from FIG. 2, the laser scanner unit shown in FIGS. 3 and 42 is shielded from the outside to prevent the scanning beam from leaking. The results of beam detection by the beam detector 346 are displayed at appropriate positions on the scanning panel shown in FIG.

FIG. 4 is an explanatory diagram of the registration roller front pass sensor 394. Manual stop switch 3 in Figure 2
28 only detects manually fed paper, whereas the purpose of the registration roller front path sensor 394 is to detect paper during paper feeding from a cassette. In FIG. 4, the paper fed from the upper 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 no light enters the registration roller front path sensor 394, so that the fed paper can be confirmed. Furthermore, if the paper is not fed correctly, the paper does not reach the position r of the registration roller front path sensor, and the light from the light emitting diode 393 continues to enter the registration roller front path sensor. To,
It can be recognized that paper has not been fed.

FIG. 5 shows a reversing tray 381 which is an optional unit.
FIG. Normally, the printer 300 is equipped with a non-reversible tray 397 as shown in FIG.

When such a non-reversing type is used, the first printing paper is on the bottom side, so the information delivery device (host system 1) has to send data from the last page, so the host There is a drawback that the method of filing information in system 1 becomes complicated. Therefore, the book reversing tray 381 is indispensable in order to compensate for the above-mentioned drawbacks.

In FIG. 5, the paper that has passed through the paper ejection roller 335 of the printer 300 is transported by the conveyance port nib 382 and 383.
The paper is stored in the tray 384 in an inverted form compared to when it passes the paper ejection roller 335.

Therefore, since the printing side of the paper is on the bottom side, the first page is on the bottom side, but if you take out the paper from the tray 384 and the printing side of the paper is on the front side, the first page will be on the top side. In this case, the last page is on the bottom 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 holding actuator to prevent the paper stored in the tray from floating; 395 is a paper ejection switch to confirm that the paper is properly stored in the tray 384; and 391 is the presence or absence of paper in the tray 384. 392 is a tray sensor on the light receiving side. When the paper 390 is in the tray 384, the tray sensor 392 is not irradiated with light, and when there is no paper 390, the tray sensor 392 is irradiated with light, so that the presence or absence of the paper 390 can be detected.

FIG. 44 shows another example of the paper presence/absence and paper full detection section. This causes the actuator 38 to rotate around the pivot point 386.
8 is provided, and a lever 398 is provided in series above,
The tip of the lever 398 is biased in one direction by a solenoid 389 as a separating means and a coil 387 as a releasing means, and the lever 398 is moved depending on the state in which paper is stored in the paper storage section 390. is detected by a detection means, for example, a plurality of sensors 401 and 402. In the various states of the actuator 388, the position 81 is "1 paper full", the position a2 is "paper present", a
Position 3 is in the "out of paper" state. The separating means 38
Reference numeral 9 separates the actuator 388 at least while the paper 390 is being discharged into the paper output tray 384, and activates the solenoid in synchronization with the current state signal when the paper should be detected, for example, during a printing operation or when the paper is stopped. 389 is turned off,
The separation of the actuator 388 is released, and a detection operation is performed. Therefore, the discharging leading end of the paper 390 does not collide with the actuator 388, and the discharging operation is not hindered.

Note that each sheet of paper sent into the paper ejection tray is detected by a paper ejection switch 395, and the contents are counted by a paper ejection memory counter (RAM 107 in FIG. 13), which will be described later, to detect the number of sheets. When one sheet becomes full, 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, 350 is a top cover of the printer 300, 351 is a front cover, and 352 is a maintenance cover.
If a paper jam or toner replenishment occurs, open it in the direction of the arrow and process it. Further, the maintenance cover 352 is
Although the front cover 351 has a structure that can be opened from the top, it cannot be opened unless the front cover 351 is opened in the direction of the arrow, to prevent the operator from operating incorrectly.

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 for selecting online/offline, and 355 is a select lamp that corresponds to the select switch 354 and lights up when online.

356 is a 1-digit seven-segment LED that displays the error details when a serviceman is called, the mode number when in maintenance mode, etc., and 357 is the printer 30.
A power lamp that indicates that the power is turned on.
Reference numeral 358 indicates a tray full lamp that indicates that the reversible tray unit 381 is full of printing paper, and 359 indicates color LC and D indicators that display details of the operating status of the printer. The total number 353 to LCD display 359 described above are constantly operated or displayed. Next, the maintenance cover 352
This section explains the parts that cannot be operated without opening the . The following parts are to be operated only by service personnel.

403 is a maintenance switch for selecting maintenance mode and replacement mode; 406 is an indicator lamp indicating that the device is in maintenance mode.

407 is an indicator lamp indicating that it is in exchange mode;
404 is a selection switch that selects the operation mode number in each mode; 408 is a selection lamp that indicates that the selection operation by the selection switch 404 is possible; 405 is a test print mode selection and the above-mentioned maintenance, replacement, and test print. 360 is a main exposure adjustment volume which will be described later, and 361 is a shadow exposure adjustment volume. Further, both the volumes 360 and 361 have a structure in which an adjustment screwdriver is inserted and turned, and cannot be turned by hand with the maintenance cover 352 open.

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

371.372 is a segment that indicates the standby, ready status, etc. of the printer 300. When waiting until the fuser is ready, 371 and 372 are both lit. When the printer is ready, only 371 is the car light, and when printing is in progress, both 371 and 372 are off. do.

373 blinks when a jam occurs in the paper feeding section, and the segment indicating the paper feeding status also blinks at the same time.

That is, the manual feed designation 365 blinks in the manual feed mode, the upper cassette 364 blinks in the upper cassette mode, and the lower cassette 363 blinks in the lower cassette mode.

374 blinks if there is a jam in the conveyance system (registration roller 329 or later). At this time, the paper feed segment also blinks at the same time, as in the case of a paper feed jam. 375 blinks when the toner pack (not shown) is full of toner collected by the cleaning blade 310 in FIG. 376 blinks when the toner hopper (not shown) of the developing device 307 runs out of toner. 377 and 378 blink when a serviceman error, which will be described later, occurs. 379
blinks when an operator call, which will be described later, occurs.

380 blinks if there is no paper in the selected cassette. 362 displays the size of the selected paper.

For example, if the upper cassette side is selected and the A4 vertical paper cassette, A4-R lights up, and if 86 is selected in the manual feed mode, 86 lights up. 363 lights up when the lower cassette is selected, 364 lights up when the slipper side cassette is selected, and 365 lights up when manual feed is selected. 366 is printer 30
It represents the shape of 0 and is always lit, 367 is the photoreceptor 30
1, which is always on; 368, which represents the top shape of the printer 300, is always on, except when the conveyance section is jammed; and 369, when the conveyance section is jammed (when the above-mentioned 374 is blinking), the above-mentioned 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 stores the dot information and image information on the dot-compatible page memory 20 corresponding to the printing area on the paper of the printer 300 after data conversion. Further, the stored data on the page memory 20 is sent to the printer 300 to perform a printing operation.

The data control unit 2 is configured to accept two types of information. In other words, one is character code information (JIS8
In this case, the character generator 15 generates a character pattern corresponding to the character code, and stores the dot information of the character pattern on the page memory 2o. 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 interface 50 via the signal line S01, and the information is further stored in the data latch 3.

Signal line 8 between interface 50 and host system 1
02 is sent from the host system 1. The data strobe signal and other control signal line S03 are a busy signal and status signal line from the data control device.

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 for character code information, where a character identification code indicating that it is character code information and a paper size code indicating the size of the paper to be printed are placed at the beginning of one page. There is.

Thereafter, character code data is entered in the order of the first line, second line, . . . nth line, and finally an END code indicating the end of data for that page. Further, character code data for one line is made up of a code indicating the character size, a character code, and an LF code indicating the delimitation of one line of data.

FIG. 10 shows a format for image information, in which an image identification code indicating image information and a paper size identification code indicating the size of paper to be printed are entered at the beginning of one page of data. After that, 1 line.

2 lines... Image data is contained in the order of m lines. Furthermore, since the data for one line is specified by the paper size identification data, it is automatically determined by counting the specified data on the data control unit 2 side. There is.

The input information from the distributor 4 is processed as follows. Information that has entered the distributor 4 is always input from the distributor 4 to the decoder 5 via the output line So4. First, regarding the case of character code information, when the character identification code shown in FIG. 9 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. The main control unit 6 determines that the input information is character code information, and instructs the distributor 4 to input the next paper size data to the page code buffer 7 control circuit 7 via a signal line 806. . Therefore, the paper size data is input from the distributor 4 to the page code buffer control circuit via the data line S07. The next 1st line, 2nd line......n
The data up to the row is input from the distributor 4 to the page code buffer via the data line SO8. At this time, the character code data is stored in the memory area on the page code buffer 79 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. EN to each page code buffer control circuit 7.
Inform D code detection. When the page buffer control circuit 7 confirms through the signal line S09 that input of character codes for one page into the page code buffer 7 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 A5 size paper, 27 is the right edge of A4 size paper, 26 is the right edge of A3 size paper, 31 is the rear edge of A5 size paper, 30 is the right edge of A4 size paper The trailing edge 29 indicates the trailing edge of A3 size paper. 32 is the address ADR (0) of the read address counter 19 and the write address counter 18.
, 0) points. Here, ADR (0,0) indicates that both the vertical address (ADRV) and the horizontal address (ADRH) are '0°. That is, the write address counter 18 and the read address counter 19 are stored in the vertical direction address <ADRV>, !, as shown in FIG. :Horizontal direction 7 dos L/su (ADRH) J
ADRV represents a vertical address (arrow b in FIG. 11), and ADRH represents a horizontal address (arrow C in FIG. 11).

43 is the last horizontal address of A3 size paper (A3HE
), 44 is the horizontal address of A4 size paper (A4HE)
, 45 is the horizontal address of A5 size paper <A38E). Similarly, 46 is the last vertical address of A3 size paper (A3VE), 47 is the vertical address of A4 size (A4VE), and 48 is the vertical address of A5 size paper (A5
VE). 33 is A size vertical address ADR
V=0. Point A of horizontal address ADRH=A38E
DR(0, A3HE), 34 is similarly ADR(0,
A4HE), 35 indicates ADR('O, A5HE), respectively. 36 is the A3 size vertical address ADRV
= (A3VE), horizontal address ADRH = O (7) point ADR (A3VE.

0), 37ha Jii] 1. :t, TADR(A4VE
, O).

38 does not show ADR (A5VE, O), respectively.

39 is the A3 size vertical address ADRV=A3VE,
Point ADR(A) of horizontal address ADRH=A38E
3VE, A3HE>, similarly 40 is ADR (A4
VE, A4HE), 4.1 is ADR(A5VE, A5
The character pattern is stored as a dot image in the page memory 20, which has a memory space of 1° or more, as shown in FIG. The character size data of the first line is read from the page code buffer 9 via the signal line 810 to the page code buffer control circuit 7.

The type of font size in this example is 40×40°32×3
The page code buffer 1 control circuit 7 determines the character size based on the read character size code, and sends the determination signal to the signal line 8.
11 to the page memory control circuit 17, a signal line 81
3 to the character generator 15. The page memory control circuit 17 controls the line feed pitch and character pitch based on the character size determination signal, and the character generator 15 switches the character size area.

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.
will be transferred to the specified area.

When the transfer of one line of character code data to the line buffer 10 is completed, the line address counter 11 returns to the initial address (
Return to 0). First, the first vertical line of the character font (line 57 in FIG. 11) is written into the page memory 20.

Here, at j, the line/scan counter 13 is set to the initial value (0
, 0>, and write address counter 1
The value of 8 is ADR (0, 0). row buffer 1
The character code data of 0 is sequentially read out in a constant cycle starting from the first digit, and latched in the output latch 12 in order to synchronize with the line counter 13. The first character code (“T” character in this example) is the output latch 12.
When latched, the character code and the output of the line/scan counter 13 are synthesized in the synthesis circuit 14 and used as a character pattern selection code for the character generator 15.
It is input to the character generator 15. here,
To explain the configuration of the line/scan counter 13, the upper 6 bits are a counter that counts scanning lines, that is, a counter in the vertical direction of the character pattern.
Count the line feed pitch control line and return to O'.

The lower 3 bits serve as a counter in the horizontal direction of the character pattern, and in the case of a 40x40 dot font, it counts O to 4 plus the character pitch control and returns to dOl (because the output of the character generator 15 is 8 bits parallel). ).

Below, the font size is 40X40. The operation in the case where the horizontal distance between characters is 8 bits and the vertical distance between one character is 8 bits will be described. As mentioned above, the first character code ('
T') is set in the output latch 12, the character code and the output of the line/scan counter 13 are combined in the synthesis circuit 14, and the character generator 15 outputs the code as a character pattern selection code for the character generator 15.
is input. At this time, since the value of the line/scan counter is (0,, O), the character generator 15 outputs the data (8 bit) is output. The output data of the character generator 15 is latched at -H by the output latch 16 in order to synchronize writing to the page memory 20, and written to the address on the page memory 20 specified by the write address counter 18 by the page memory control circuit 17. be included. In this case, since the value of the write address counter 18 is ADR (0, 0), it is written to vertical address "O' and horizontal address '0'. Then, the 1-byte character pattern When writing is completed, the value of the line/scan counter becomes (0,
1), and the value of the write address counter 18 also changes to ADR(0, 1>. Therefore, the output of the character generator 15 is the ``0'' line in the vertical direction and the ``1 degree'' in the horizontal direction of the character pattern. After the th data is output and latched in the output latch 16 as described above, the page memory 2
It is written to the ADR (0,1) address of 0. In this way, the end (
When the writing of data ('4'4' data) is completed,
The value of the line/scan counter is (0, 5>), and the write address counter 18 is DR (0, 5>).The horizontal spacing between characters is 8 dots (1 byte), so the character All outputs of the generator 15 are forced to "
O' is written to address ADR (0, 5) of the page memory 20, and after the write operation is completed, the row address counter is incremented by "1" and the next character code is output from the row buffer 10. It is set in the latch 12. Also, the line/
The scan counter becomes (0, 0), and the write address counter 18 becomes ADR (0, 6). Therefore, the next operation is to write the data of the 0' character pattern vertically on the "0" line into the page memory 20. At this time, the write address counter 18 is set to ADR (0, 6), (0, 7). ), (0
, 8), (0°9), and (0, A), and the character pattern data of 0 is written to the address specified by the writing address counter 18, respectively.

Then, the value of the write address counter 18 is (0°B),
When the value of the line/scan counter 13 becomes (0°5), 0' is written to the page memory 20 as described above, and after the write operation is completed, the row address counter becomes plus 1.
1', and the next character code is set in the output latch 12 from the line buffer 10.

Further, the line/scan counter 13 becomes (0°0), and the write address counter 18 becomes ADH (0°0).

In this way, the character pattern data of the 0'th line in the vertical direction is sequentially written into the page memory 20.
When the 'LF' code is output to the output of the line buffer 10, the 'LF' code detection signal is transmitted to the page code buffer control circuit 7 through the output line 814, and the writing operation of the character pattern from the character generator 15 is stopped. do. From then on, the write address counter 18 is sequentially incremented by ``1'' and ``O'' is forcibly written to the page memory 20.Then, the value of the write address counter 18 indicates that A3 size is currently specified. AD
When the value of R(0, A3HE>, that is, the 33rd point in FIG. /Scan counter 13 is (
1, 0>, respectively. Then, 'T', which is the first character code from the line buffer 10, is set in the output latch 12 again. Then, the character pattern data of the ``1'' line in the vertical direction of the character pattern is written into the page memory 20. In the same way, the vertical direction of the character pattern is "2'."

3'... When the write operation up to the 39th line is completed, the write address counter 18 is set to ADR (28,0
), the row address counter 11 is (0).

The line/scan counters 13 are set to (28, 0), respectively. This completes the writing operation of character pattern data for one line, but next, since the line feed pitch is every 48 lines, 101 is forcibly written to the page memory 20 for the remaining eight lines. and 8 lines of j O
When the writing of l is completed, the writing address counter 18
The address value of is at point 1 in FIG.
The row address counter 11 is (O) at ADR (30,0).
.

The line/scan counters are each set to their initial values (0, 0>). This completes all write operations including the line feed pitch for one line. Character code data is transferred from the page code buffer 9. When the transfer of character code data is completed, the line address counter 11 returns to the initial address (0). After that, the same operation as writing the character pattern data in the first line is performed. Writing of the character pattern data on the second line is performed. Therefore, when the writing 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 address value of the row address counter 11 is ( 0
), the 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, as soon as an ``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 1 control circuit 7 forcibly sets the output of the character generator 15 to 101 via the signal line S13, and notifies the page memory control circuit 17 that writing of character pattern data has ended.

After receiving the write end signal, the page memory control circuit 17 selects the final memory address (39 point ADR (A3VE) in FIG. , A3
1-IE)) tF Forcibly write 0'. and the 11th
Writing "O'" at the point in FIG. ), row address counter 1
1 is (0), line/scan counter 13 is (0,0
) are all initialized.

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 805. The main control unit 6 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 s06.

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. ...Image data up to l 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, the page memory control circuit continues the process (image data is transferred to 32 points (address ADR (0, O) in FIG. 11).
The write address counter 18 is set to ADR (
0,0). Then, the data length for one line in the horizontal direction is determined as J: by referring to the table in the page memory control circuit 17 based on the paper size identification code.

1. Therefore, if the paper size of the image information to be input into the page memory 20 from now on is A4, the data length of one line is the value up to 44 points (A48E) in FIG.
That is, A4HE'. Naturally, the length of the image information per line sent from the host system 1 is 'A'.
4 HE ', so image data 19 image data 2 in FIG. ...The data length of image data m is "A4VE', and the number of image data ■ is as shown in Fig. 11 47
The point value is A4VE'. Therefore, the image data 1 in FIG. 10 is stored in the page memory 20 as follows.
Figure 11, 32-point ADR (0, O) to 34-point ADR (0°A4HE), image data 2 is a 51-point line, image data 3 is a 52-point line...
...The image data I is a 37-point line, so the final address is a 40-point ADR (A4VE, A4HE
). 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 output 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 817. In FIG. 8, 817 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, S19 and S20 are strobe signal lines when sending command data and print data,
S21 is a busy signal line from the print control unit, S22 is
826 is a horizontal synchronization signal line from the print control section, S23 is a page end signal line that also indicates the end of print data, S24 is a ready signal line of the print control section, S25 is a print request signal line that indicates a printable state. A select signal line (2 lines) that specifies the data content of the data line in the interface bus 817.

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 unit, printing from the data control unit 2 is started via the start signal line 827.
In contrast, the print control section sends a horizontal synchronization signal 822.

This horizontal synchronizing signal 822 first sequentially sends out 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 S23 is received, and the data in the designated area of the page memory 20 is sent to the print control unit.When the page end signal S23 is received, the data sending is forcibly stopped. In the print control section, the page end signal 823 is output at the same timing as the horizontal synchronization signal 822. In addition, in correspondence with the memory addresses in FIG. 11, the last line A3 of the memory area of the paper size has 46 points 1 to 46 points, and A4 has 46 points.
It is output from the print control unit at the same timing as 7 points or earlier.

Further, in the page memory control circuit 17, the page memory 20
When the sending of print data starts, the values of the read address counter 19 and the write address counter 1h are always compared, and if the value of the read address counter 19 is larger, the sending of that data is finished. control is performed to permit write operations to the memory area that has been accessed. 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 2102 for controlling each unit in the microprocessor 101 is an interrupt control circuit for controlling interrupts to the microprocessor 101, and a command signal line 330. 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. A ROM (read only memory) 104 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 the 45th
Shown in Figure (A). In figure M45 (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) respectively contain write margin control data. Similarly, addresses (4008 to 400F>) contain data for controlling the top, bottom, left, and right margins for paper size B4.The following margins correspond to various paper sizes up to address (4087). Contains control data.These margin control data are sent to the print data write control circuit 11, which will be described later.
This is used as set data for the margin control counter in 9.

Addresses (4100 to 41FF) contain a table of command codes for specifying operations from the data control unit 2, and are used for checking command codes from the data control unit 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 42FF) contain data on the charging characteristics of the photosensitive drum 301, including five types of data A to F. This data is then used for temperature correction control of the charging charger 304, which will be described later. Addresses (4300 to 43FF) are an exchange data table, and photosensitive drum 301. It contains replacement cycle data for the developer in the developing device 307 and the fixing roller 332.

The addresses (4400 to 47FF) are 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 microprocessor
101 compares the cassette size stored in the paper size register with the size of recorded information (image data, etc.) from an external device sent from the data control unit 2, and determines that the cassette size is larger. The subsequent printing control section 100
It is designed to issue printing operation commands to the printer. Therefore, it is possible to print even if the printing paper is larger than the size of the information sent from the outside, and the usability can be improved. Reference numeral 107 is a non-volatile RAM, and the data in the memory is retained even when the power is cut off. Further, the data contents in the nonvolatile generation RAM are shown in FIG. 45(B). In Fig. 45<8), the address (6000) contains the drum characteristic number input from the operation unit in the exchange mode, and the address (6100) contains the jam information at the time of jam occurrence. It is used to prevent forgetting to dispose of jammed paper inside the machine when the power is turned off. address(
Reference numeral 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 maintained by 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 operation section that the drum should be replaced.

Address (6400) is the developer exchange counter, which is incremented by 1 for each print as in the case of drum exchange, and when the value of this counter reaches the value of the exchange table (developer) in Figure 45 (A>). displayed on the operation panel.

Address (6500) is a fixing roller replacement counter, which is incremented by 1 for each printing as in the case of drum replacement, and when it reaches the value in the replacement table (fixing roller) in FIG. 45(A), it is displayed on the operation unit. .

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 port 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 board 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 PIN diode that responds at high speed is used. There is.

121 is a high-speed comparator for digitizing the analog signal from the beam detector and creating a horizontal synchronization pulse; 119 is a high-speed comparator for digitizing the analog signal from the beam detector; This is a print data write control circuit that controls writing to the test pattern and generates test pattern print data. 122 is an interface circuit that controls output of status data 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 multiplexer, an 8-bit signal S32 is inputted to the input port 112 in FIG. 13 by a select signal S31.

Reference numeral 320 denotes an upper cassette size detection switch, which is composed of four switches, and the combination of these switches indicates the paper size. , 324 is a lower cassette size detection switch, which has the same configuration as the upper cassette size detection switch. Reference numeral 319 is a cassette upper paper out switch, which is turned on when the cassette runs out of paper. 323 is an upper paperless switch. 123 is a pass sensor in front of the registration roller, and a CDS light receiving element is used. This sensor is
A bias voltage is applied through a resistor (not shown), and the output voltage changes depending on the presence or absence of paper. Therefore, by inputting the output to the comparator 124 to which the reference voltage Vre[1 is applied, a signal for determining the presence or absence of paper can be obtained.

Reference numeral 326 indicates a manual feed switch for detecting 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 ref2 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 provided in the fixing device, 131 is a drive power supply (+24VB>
This is an MC relay that turns N10FF. Since one of the temperature fuses 130 is connected to the power supply +24VA,
When the temperature fuse 130 is blown due to an abnormality in the fixing device, the MC relay 131 is turned off and the driving power is turned off.
F is given. Further, the temperature fuse 130 is connected to a resistor RO1, and one end of the resistor RO1 is connected to a resistor RO2 and an input of a comparator 132. Further, a reference voltage Vref3 is applied to the other input of the comparator 132. Therefore, when the temperature fuse 130 blows, the input of the comparator 132 becomes Ov. Therefore, the comparator 132 outputs a temperature fuse blowout detection signal. 133 is a destination selector switch, and specifically, this switch is set to 0N10FF, so that the ON state is for 8 and B size for domestic use, and the OFF state is for the United States (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, depending on the state of this switch, the
Select one of the paper sizes for the US.

134 is a jam hit switch, which is installed inside the front cover. Is this switch ON to confirm after the operator has cleared the jam or replaced the toner bag when a paper jam or toner full operator call occurs? It is a switch. Therefore, unless this switch is turned ON after the above processing, the jam or full toner display on the operation panel will not be cleared. Reference numeral 392 is a paper discharge tray sensor for detecting paper in the tray shown in FIG. 334
is a thermistor that detects the temperature of the fixing device, and is controlled so that the detected temperature of this thermistor is constant. Thermistor 3
34 output is resistor RO3 and comparator 136.137
connected to the input side of the 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 RO7 is applied, and the output of the comparator 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 the transistor 138. Therefore, when this transistor 138 is turned on by the input signal (power save signal) 83, the comparator 136
The reference voltage of is lowered by resistor RO8, and the temperature control of the fuser is lower than when transistor 138 is OFF. Therefore, the power consumption of the fixing device becomes low and the fixing device enters a power save state. Further, the reference voltage of the comparator 137 is given by the voltage division of the resistors RO4 and R○5. Since the reference voltage of the comparator 137 is set much 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. And output S3 of comparator 136
3, one side is input to the multiplexer 139,
Read by 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, the input voltage of the operational amplifier 270 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. The operational amplifier 270 serves as a voltage follower, and its output 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 charge correction of the photoreceptor 301, which will be described later. 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 a PLL like the developer and fuser driver described above.
No speed control is performed. 147 is the photosensitive drum 30
1 drive motor, and uses a 4-phase pulse motor. 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 40
It is about 0 PPS.

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 5322 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 on the photoreceptor 301 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.

A pre-transfer static elimination lamp 303 is placed in front of the transfer charger to increase transfer efficiency, and is composed of a plurality of red LEDs. 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. Reference numeral 158 denotes a solenoid for a toner collection blade, and when this solenoid is turned on, the blade 310 is pressed against the photoreceptor 301. 154 is a driver for the blade solenoid 158. Reference numeral 159 denotes a toner replenishment motor for replenishing toner from the toner hopper to the developing device 307, and as this toner replenishing motor rotates, toner is replenished from the toner hopper to the developing device 307. The operation of the toner supply motor 159 is performed according to the output of the prologue concentration detection sensor shown in FIG. 14. 155 is a driver for the toner supply motor 159. 131 is an MC relay that operates in conjunction with the door switch similar to that shown in FIG. 14, and 156 is its driver. Then, as shown in Fig. 15, M
The power supply side common for motors, lamps, etc. that excludes the C relay 131 is connected to the contact 163 of the MC relay 131, and the other contact is connected to the +24VB power supply.Therefore, when the MC relay 131 is turned on, the It has a configuration that allows the motor and lamp to operate.

304 is a charger for charging, and the case of the charger 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,
An 0N10FF signal line S35 for high voltage output and an analog control signal line S36 for changing the high voltage output current are connected to the input of the high voltage power source for charging. Further, the analog control signal line 836 is connected to the D/A converter 165,
Data from the charging voltage control data line 337 from the microprocessor 101 is converted into an analog voltage by the D/A converter 165 to control the output current of the charging high voltage power source. 306 is a peeler charger, and the peeler charger 306 is connected to the output of the high voltage power source 161 for peeler. The high-voltage power source for peeling has an AC output.

Reference numeral 305 is a transfer charger for transferring the developed toner on the photoreceptor 301 onto a sheet of paper, and the transfer charger is connected to the output of a high voltage transfer electric current [62]. In addition to the transfer charger output, the high-voltage transfer power source also incorporates a developer bias power source, and its output line 838 is connected to the developer magnet roller 308. This voltage applies a bias voltage to the magnet roller 308 to provide a developing bias. 33 is a heater lamp of the fixing device, one side of which is connected to one of the power sources of the ACI OOV.

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 S33 and 839 are input to 66, and S33 is the thermistor 33 in the fixing unit 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, L03, and LO4 are motor coils, and 180, 181, and 182 are Hall elements that detect the position of the motor rotor, respectively. 183:18
4.185 is a comparator for the Hall elements 180, 181.182, and its output is connected to the base of the power transistors 171, 172 and 173 which drive the motoriles LO2, LO3, 104 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 are turned on in the order of 173, 172.
rotates. In addition, the output of the comparator 185 is passed through the diode 002 to the resistor R30 and the capacitor C0,6.
, and is input to a frequency dividing counter 175 through a waveform shaping circuit including an inverter 174. Frequency division counter 175
The outputs of the output terminals Q1 and Q2 are connected to the motor speed switching gates 176 and 177, and the output of the speed switching gate passes through the OR gate 178 to the PLL (
(phase, lock, loop) control IC's FG large input is connected. Also, the speed switching gate 176177
The output of the speed control signal line 840 and its inverted output are connected to one input of the speed control signal line 840. Therefore 840 is LOW
In the case of level, the switching gate 177 is enabled and the output of 01 of the frequency division counter is applied to the FG of the PLL control IC 167.
When S40 is at HIGH level, the switching gate 176 becomes valid and the output of the frequency division counter 175Q2 is inputted to the FG large input of the PLL control IC 167. Here, to briefly explain the input/output signals of the PLL control ICl67, the P/S terminal (PLAY/5TOP) is HIGH.
It stops at level and starts at LOW level.

In the case of HI G +- 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 the signal to switch the frequency division number of the reference frequency divider inside this IC, 33/45 is the motor rotation speed switching signal, CPO
UT is a crystal reference frequency division output signal, CPIN is a reference frequency input, and LD is a lock detection signal, which outputs a HIGH level when the motor rotation speed is within the lock range, and a LOW level otherwise. AFC is the output of the motor speed control system and the output of the 8-bit D/A converter inside the PLL IC.
PC is the output of the motor phase control system and is the output of the 8-bit D/A converter inside the PLLIG. Also PLLIC16
xol connected to 7 is a crystal oscillator for generating a reference frequency, and COl and CO2 are oscillation capacitors.

The AFC and APC output terminals of the PLL control IC 167 constitute an adder circuit with resistors R12 and R13, and an operational amplifier 16.
It is connected to one side input terminal of 8. operational amplifier 168
A voltage obtained by dividing +12■ by resistors R14 and R15 is applied to the input terminal on the child side. Further, a negative feedback circuit is formed by the resistor R16 and the capacitor CO3, and the capacitor CO3 in particular functions 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. operational amplifier 16
The output of 8 is a pulse width modulation switching regulator I.
It is connected to the ten input terminal of C169. 169 is a commercially available pulse width modulation switching regulator IC.
It is. This IC 169 and power transistor 170. The diode DO1, coil LO1, and capacitor CO5 constitute a down switching regulator circuit. In the input/output of the IC 169, one terminal is a comparison reference voltage terminal, and a reference voltage obtained by dividing the voltage of the reference voltage output terminal VREF inside the IC 169 by resistors R17 and R18 is applied. The DEADT IME terminal regulates the maximum pulse width of the output, and connects the VREF to the resistors R19 and R.
A voltage divided by 20 is applied. 01. C
2 is an output terminal, and the pulse width changes depending on the voltage value of the input terminal. That is, when the + side input terminal voltage is lower than the one side input terminal voltage, the path width on the LOW level side of C1 and C2 becomes small, and the power transistor 170 becomes
The width of N also becomes smaller.

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

Moreover, when the + side input terminal voltage is higher than the one side input terminal voltage, contrary to the above, the pulse width of C1 and C2 becomes large and the voltage across the capacitor CO5 also increases.

The rotation speed control of the scan motor 312 will be explained below.

The rotation start signal 842 of the scan motor 312 is 1, -
When the o w level is reached, the AF of PLL control IC167
Since the voltages of C and APC are at the LOW level until the aforementioned lock signal S41 is output, the operational amplifier 168 outputs a voltage of t IIGI - level. Therefore, the output pulse width of the regulator IC169 becomes large, and the voltage across the capacitor CO5 becomes about +16V. Since any one of the Hall elements 180, 181, and 182 is turned on at the position where the motor rotor is stopped, the motor coils LO2, L03,
Of the LO4, the coils corresponding to the Hall elements 180, 181, and 182 are excited, and the scan mode Ij312 starts rotating. The scan motor 312 then speeds up its rotation. The level of the speed control signal line 840 is now HIGH.
Since it is at H, the Q2 output of the frequency division counter 175 is applied to the FG input terminal of the PLL 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 PLLIC1
When it reaches about 96% of the reference frequency inside the 69, the lock signal LD S41 becomes I I G l-1 and AFC,A
The PC output level is not fixed to LOW level (OV), but P
Switched to the output voltage of the LLIC 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 AP'C.

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, about 6ooo during standby
rpm.

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

In FIG. 17, 344 is a semiconductor laser diode, which is composed of a laser diode main body 259 that emits light, and a monitoring photodiode 260 that is a light detection means that monitors the intensity of the output beam 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. Resistance R
50 is a current detection resistor, 258 is a laser diode 2
59 is a transistor which is a second current driving means for flowing a bias current, R51 is its current limiting resistor, R5
2 is a base current limiting resistor of the transistor 258.

254, 255, and 256 are high-speed analog switches for modulating the laser diode 259, and when a voltage of HIG)-Level is applied to the gate (G) of each analog switch, the drain (D) and source (S )
The resistance between the two becomes low and the ON state is reached. When a LOW level voltage is applied to the gate (G), it becomes high resistance and turns OFF.
become a state. The output power from the laser 259 has three levels in this laser printer. First, by turning on the analog switch 254 with the output P (ON) to almost completely remove the electrical charges on the photoreceptor 301 in a portion corresponding to the white background on the paper, the laser diode 259 outputs the output P (ON). It becomes P (ON).

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
6, the output of the laser diode 259 becomes OFF, that is, P(OFF>.The third output is the output P(SH) between the first output P(ON) and the second output P(OFF)(7). ) to increase the printing density of one dot line, and by turning on the analog switch 255, the laser diode 259 outputs the output P.
(SH) (details of P(3H) 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 driver. CO9, CIO
, C11 is a speed-up capacitor, R47,
R48 and R49 are the gate drivers 249 and 250
, 251 input resistance.

246 is a 3NAND gate, and when all three gate inputs become HIGH level, the output becomes LOW level, turning on the analog switch 254, and the laser diode 259 becomes in the output P (ON) state. 3
The first of the two 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 at HIGH level, no printing at LOW level). The second is inverter 25
The input of the inverter 252 is connected to the output of the inverter 252, and the shadow signal 848 (shadow on at HIGH level,
(OFF when set to LOW). The third signal is connected to a laser enable signal 849 (high level: laser enable; LOW: forced laser OFF).

Therefore, the condition that the output of the NAND gate 246 becomes OW level is that the laser enable signal 849 is HIGH.
H, shadow signal S48 is LOW, print data signal 84
7 is when it is OW. Next, 247 is a 3NAND gate, and when all three gate inputs become HIGH (level), the output becomes LOW level, turning on the above-mentioned blog switch 255, and the laser diode 259 becomes in the above-mentioned 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 347, and the third to the laser enable signal S49. The conditions for the output of the NAND gate 247 to be LOW level are that the laser enable signal 849 is HIGH and the shadow signal S48 is HIGH.
GH, when the print data signal S47 is LOW. Next, 248 is a 2OR gate, and when one of the two gate inputs becomes LOW level, the output becomes 10W level, turns on the analog switch 256, and laser diode 259 turns OFF state output P ( OFF) state.

245 is a sample-and-hold IC, which converts the output of the laser diode 259 into the shadow output P (S
H).

ANALOG-INPtJT is the analog voltage input to sample, SAMPLEC is the hold capacitor CO8
The connection terminal 5TROBE is a sampling strobe signal terminal and is connected to the sample strobe signal 846. 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. Also, the resistor R40 and capacitor CO7 constitute an integrating circuit, and the resistor R41
is a discharge resistor that discharges the charge of the capacitor CO7 at a constant rate. 236 is an analog switch whose gate (G) is connected to a buffer 244, and a sample signal 845 is input to the input of the buffer 244. 253 is a transistor for level conversion, and R39 functions as a current limiting resistor when charging the capacitor CO7. R38 is a base current limiting resistor of the transistor 235, and 234 is a comparator serving as comparison means. This comparator has a hysteresis characteristic due to the action of resistors R34 and 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 23
This is a resistor that regulates the degree of amplification. Therefore, the volume V
By changing RO1, 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 344, and a voltage proportional to the output current of the photodiode 260 is obtained. Optical output P of photodiode 260
The relationship between short circuit current is and O is shown in FIG. 1st
In FIG. 9, is indicates the monitor current, and Po indicates the optical output of the laser diode 259. The output of P(ON> is approximately 6n+w, the output of P(SH) is approximately 4mw, and the output of P(OFF
) is O. Further, LA-A and LA-8 represent two types of laser diode monitor characteristics.

Normally, the volume VRO1 is adjusted so that the output voltage of the operational amplifier 232 is about 3V when the laser diode optical output is 6111W. Therefore, the characteristics of both graphs LA-A and LA-8 in FIG. 19 can be adjusted by the volume VRO1.

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 + side input. Also-
A voltage divided by resistors R36 and R37 (in this case, it is set to 2.0 mm) is applied to the side.

Therefore, the laser diode 259 emits light and its output is about 211IW bell, which changes from the LOW level to l-110H.
The level changes and a laser ready signal 843 is output. Further, a laser light 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. A voltage is input to the input terminal of the voltage follower 239 after being divided by a main exposure adjustment volume 360, which is a first voltage variable means, and a resistor R45.
By varying 0, the voltage at one terminal of the comparator 234 also changes. Further, the analog switch 241 is turned on when the laser output P (SH) is set, and the output voltage of the voltage follower 239 is connected to the resistor R46 and the second
A shadow exposure adjustment volume 36 is a voltage variable means for
A voltage divided by 1 is applied to one input terminal of the comparator 234. The above voltage follower 239, analog switches 240, 241, main exposure adjustment volume 360. Resistor R45, shadow exposure adjustment volume 361. The resistor R46 constitutes a light output setting means. Further, a circuit that compares the voltage detected by the monitor photodiode 260 and amplified by the monitor amplifier 324 with a set voltage by the comparator 234, and integrates the comparison value is called an 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 a LOW level, the output level of the inverter 242 becomes a HIGH level, and the analog switch 241 is turned on. Further, when the main exposure setting signal 844 is at the HIGH level, the output of the buffer 1243 becomes the IGH level and the analog switch 240 is turned on. Also, the output (S side) of the analog switches 240 and 241 is The output 850 of the voltage follower 261 is also input to the voltage follower 261, and is used to correct the threshold level of a horizontal synchronizing pulse detection comparator of a beam detection circuit, which will be described later.

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. TO=O℃ is the IF-Po characteristic when the case temperature of the laser diode 344 is O℃,
Same < TC=25℃, when case temperature is 25℃, TC=50
°C is the IF-Po characteristic when the case temperature is 50 °C. Taking the characteristic of case temperature TC=25° C. as an example, when the current IF flowing through the laser diode 259 is gradually increased from 0, the optical output po starts to be output from the point of about 5 On+A. Then, at the point of IF=68mA, the above P (
ON) optical output is 6 mw.

Therefore, even when TO=0°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 is always IFB is supplied to reduce the power loss of the laser modulation transistor 257. Therefore, the operation of the laser modulation transistor 257 is guaranteed to be extremely stable even at high temperatures due to the action of the bias current IFB. Also, if the amount of change in current required to modulate the laser is, for example, TC = 25°C, the value is 1F25 - IFB.Compared with directly driving the current of <lF25 with the transistor 257, the light amount stabilization will be described later. The accuracy of the movement can be improved considerably. 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. In this laser light amount stabilizing circuit, the light amount from the laser diode 259 is detected by the monitor photodiode 260, and the short circuit current Js of the photodiode 260 is controlled so as to always be a constant amount. In this case, as is clear from FIG. 19, the monitor short-circuit current IS and the optical output po of the laser diode 259 are in a perfect proportional relationship, so the monitor current ■
If 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 Fig. 7 is turned on, and a bias current (approximately 3
On+A) flows.

Also, at this time, since the print data signal S47 and the screen signal 5II8 are both at LOW level, only the input to the gate 246 among the gates 246, 247, and 248 becomes l' (I G l-level). Output is LO
W level becomes analog switch 254, 255, 25
6, the analog switch 254 is in the ON state. Furthermore, when the sample signal S45 becomes l-I I G l-(, 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 base of the laser modulation transistor 257 is also OV.
It becomes v. Therefore, at this point, the laser diode 24
Only the bias current flows through the transistor 9, and the laser diode does not emit light, as can be seen from the characteristics shown in FIG. Photodiode 260 for laser diode monitoring
Since the laser is not emitting light, the monitor current is
is 0, and the output of the operational amplifier 232 is oV, so the output of the comparator 234 is LOW.
level, and the transistor 235 is turned off.

Since the transistor 235 is OFF, the capacitor CO
7 is charged through resistors R39 and R40. The time constants of the resistor R39°R40 and the capacitor 007 during charging are selected to be approximately 20 to 50 IIISeC.

If this value is very small, the response of the stabilization circuit will be too fast,
Fluctuations in the laser light output level increase. Moreover, if it is too large, the responsiveness will deteriorate and it will take time for the optical output to stabilize. As the capacitor CO7 is chipped, the output voltage of the voltage follower 237 also gradually increases. Therefore, as the base voltage of the laser modulation transistor 257 increases, a current flows to the collector. The transition at this time was 1257(1)koL
/') Evening'R flow 1c is (VB-VBE(SAT>3/R
The current value is 50. 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 IC increases, and the 7-ode current IF of the laser diode 259 becomes approximately 50 mA (TC
=25°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, so that the voltage at the ten input terminals of the operational amplifier 232 increases, and the output voltage is also a value obtained by amplifying the input voltage. Output. and op amp 23
Since the amplification degree of 2 is adjusted in advance by the volume VRO1 so that the output voltage of the operational amplifier 232 is approximately 0.5V for the output 1mW of the laser diode 259, the optical output of the laser diode 259 increases, and the output voltage of the operational amplifier 232 increases to approximately 2.
mw, when the output voltage of the operational amplifier 232 reaches approximately 1V, the output signal of the comparator 238, that is, the laser ready signal S43 changes from LOW to 1-IIGH level. Since the main exposure setting signal 844 is at LOW level, it is passed to the one side input terminal of the comparator 234 through the analog switch 241 to the shadow exposure level (light output P (
SH)) voltage is applied. This voltage is applied to the photoreceptor 30
The shadow exposure level voltage is set according to the sensitivity characteristics of 1 by a shadow exposure setting volume 361 in the operation section. Assume now that the voltage is 2.0V, which corresponds to an average optical output of 4 mW. Therefore, the optical output of the laser diode 259 increases and the voltage at the input terminal of the comparator 234 becomes 2. When the voltage exceeds OV, transistor 235
turns on, and capacitor CO7 is discharged through resistor R40. Therefore, the base voltage of the laser modulation transistor 257 also decreases, and the laser diode 2
The optical output of 59 is less than 4mW. When the optical output of the laser diode 259 becomes 4mW or less, the comparator 23
The + side input terminal voltage of No. 4 also becomes 2.0 V or less, and the transistor 235 is turned off again.

Then, the capacitor CO7 is charged up again through the 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 01 in FIG. 20 and becomes stable. After the laser ready signal 843 becomes HIG)I level, the microprocessor 101 outputs a shadow level sample strobe signal S46 after a predetermined time t6 has passed through the output port. When the sample strobe signal is output, the sample hold IC 245
The voltage VOI (FIG. 20) of the capacitor CO7 input to the NALOG-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) is applied to the output OUT of the sample and hold IC.
continues to be output.

Next, when the sample and hold operation of the shadow level P (SH) is completed, the microprocessor 101 outputs the output capo-1.
The main exposure setting signal S44 is switched to HIGH level through ~. 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 adjusted according to the sensitivity characteristics of the photoreceptor 301 by the main exposure setting knob 3 in the operation section.
It is assumed that a voltage of 3, OV, which corresponds to an average optical output of 5 mw, is currently being output with the voltage set by 60. Therefore, the output of the comparator 234 goes to the LOW level because the input terminal on one side is switched to 3.0■, and the transistor 235 turns 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. When the optical output of the laser diode 259 is around 6 mW, the output voltage v232 of the operational amplifier 232 is about 3 V.
become. When the output voltage of the operational amplifier 232 becomes 3■ or more, the comparator 23
The output of 4 changes to 110H, and the transistor 235 turns OFF.
N, and capacitor CO7 is discharged through resistor R40. Therefore, the base voltage of the laser modulation transistor 257 also decreases, and the laser diode 259
The light output will be less than 6mW. laser diode 25
When the optical output of 9 becomes less than 6mW, the comparator 234
The + side input terminal voltage of the transistor 235 also becomes 3.0 V or less, and the transistor 235 is turned off again. And again capacitor C
O7 is charged up through resistors R39 and R40, and the optical output of laser diode 259 becomes 6 mW or more.

In this way, the comparator 234 repeats the oNloFF operation at a constant cycle when the optical output of the laser diode 259 is around 6 mW. And the resistors R39 and R40
Due to the integral effect of
It becomes stable as it approaches figure VO2. When the setting of the main exposure level is completed, the microprocessor 101
The operation of a sampling timer, which will be described later, is started to write print data onto the photoreceptor 301. The sample timer is triggered one after another at a constant period T each time a laser beam detection signal, which will be described later, arrives, and outputs the sampling signal 845 only in a portion other than the print data write operation, that is, in the period shown in FIG. 20a. And print data S
47 and shadow data 848, the sample signal 845 is at a LOW level, so the analog switch 236 is turned off. Therefore, the laser diode 25 is activated by the print data D4.7 and the shadow signal S48.
9 is a laser diode 259 in the printing area to be modulated.
The optical output level of P (ON), P (
There are three levels: SH) and P (OFF). That is, first, the print data conversion 8S47 is OFF, that is, LO
When the shadow signal is OFF at W level, that is, it is LOW level (the output of printing is white), the NAND gate 246 is established and only the analog switch 254 is ON.
Therefore, 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)=6II1w. Second
The print data signal 847 is OFF and the shadow signal is ON.
In the case of (the printing output is halftone), the NAND gate 247 is established and the analog switch 25
5 is turned on, and the output voltage VO of the sample and hold IC 245 is applied to the base of the modulation transistor 257.
1 is applied, and the optical output of the laser diode 259 is P
(SH)-4mw. The third is print data signal 847
is ON and the shadow signal is OFF (black output is printed), the OR gate 248 is established and only the analog switch 256 is turned ON. Therefore, the base of the modulation transistor 257 is shot to GND and becomes ov, so the optical output of the laser diode 259 is P (O
FF)=0 and no light is emitted. In this manner, the first printing is performed. When printing is completed, the microprocessor 101 sets the main exposure setting signal 844 to LOW level again through the output port, and resets the shadow exposure level P (SH). Therefore, comparator 234
The voltage at one side of the input terminal becomes 2.0V, which is the setting voltage for the shadow exposure level. Therefore, the transistor 235 is turned on, and the capacitor CO7 is discharged and the VC
O7 is getting 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, and when the same current is passed through the laser diode 259, the optical output po decreases. It ends up. Therefore, in order to obtain the same optical output, IF is the current △IF corresponding to the characteristic curve shifted to the right.
only has to be increased. Therefore, capacitor CO
The voltage VCO7 of step 7 is set to VO3 which is higher than the first setting voltage VO1 by the voltage ΔV1 corresponding to the ΔIF, and the optical output of the laser diode 259 is set to P(SH)=4 mw, which is the same as the first setting. Ru. and the first
Similarly to the second time, the sample strobe signal 846 causes the sample hold IC 245 to output the shadow exposure level P(
ON) is set. At this time as well, the operation corresponds to the temperature rise in the case of the laser diode 344, and the voltage of the capacitor CO7 is set to VO4, which is higher by the correction voltage Δv2 due to the temperature rise, and the second printing is performed after the setting. In this way, the shadow exposure level P(S
H) and the main exposure level P(ON) are very accurately maintained at constant levels by the function of the 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 when printing data is being written. Furthermore, for the shadow exposure level, a sample bold operation is performed before the start of printing of each character, 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 the island value increases, and the shadow level is an auxiliary element compared to the fluctuation of the main exposure level, so even if it fluctuates a little, it does not have much effect on the print quality. In addition, photoreceptor 2
When changing the setting voltage input to the comparator 234 according to the sensitivity characteristics of 01, the main exposure setting volume 360 is adjusted. This main exposure setting volume 360 is adapted to vary the input voltage of the voltage follower 239. Therefore, by varying the main exposure setting volume 360, the light output setting voltage at P (ON) can be adjusted. On the other hand, the light output setting voltage at P (SH) is determined by connecting the output voltage of the voltage follower 239 to the resistor R46 and the shadow exposure setting volume 361.
The pressure is divided by Therefore, by adjusting the main exposure setting volume 360, the light output setting voltage at P (ON) and P (SH) times changes proportionally, and the constant relationship between recording density and applied voltage is maintained. can be kept. Therefore, when P(ON), P(S
The adjustment becomes simple without requiring the complicated operation of varying and adjusting the set voltage for H).

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.
The 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, the + side input terminal of the comparator 262 has resistors R53 and R5.
A voltage divided by 4 is applied through the resistor R56. Further, a capacitor CI2 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 D4 is connected to the + side input of the comparator 262.
Threshold variable voltage S through 0° resistor R57
50 is applied. This threshold variable voltage S
50 is the output of the analog switch 240 or the analog switch 241 (output of the optical output setting means) (see FIG. 17). FIG. 22 shows the relationship between the input waveform of one terminal of the comparator 262, that is, the output waveform of the beam detector 346, and the positive terminal voltage of the comparator 262, and the relationship between the output waveform of the comparator 2.62 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) to one input terminal of the comparator 262 as shown in FIG.
, b are input. Assuming that the voltage at the + side input terminal of the comparator 262 is always a low voltage VO6 because the threshold variable voltage S50 is not applied, the output waveform of the comparator 262 is a waveform a.
In the case of , the output waveform is as shown by the dotted line, and in the case of waveform , the output waveform is as shown by the solid line. Here, waveform a shows a cut-off waveform when the sensitivity of the photoreceptor 301 is low and the laser output during the main exposure is 611 IW or more, or conversely, when the sensitivity of the photoreceptor is high and the laser output is 5 mW or less. As can be seen from this output waveform, when the positive voltage 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. 23(A) and 23(B) 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, 4 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 light receiving element size of 2.5 x 2.5 mm and a response time of 4 n5 ec.

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 in accordance with 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 is the 27th!
The waveform is shown in Figure 1. 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, the light receiving cable 41
By attaching a mask 412 that does not allow the laser beam 413 to pass on the light-receiving surface of the laser beam 413, cracking of the output waveform when the beam passes on the end face is prevented. The mask 4
12 is a light receiving element 4 as shown in FIGS. 23(A) and 23(B).
The laser beam 4 is provided with a four-cornered window in a structure that does not include the end face portion of the laser beam 10 and the lead-out portion of the electrode wire 411.
13 is configured such that light hits 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 noise-free waveform like 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:
In order to write the print data S57 from 2 to a predetermined area on the photoreceptor 301 according to the size of the paper to be printed, the parallel print data S57 is serially converted and 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 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 for transmitting and receiving signals necessary for control within the laser modulation circuit 120 and 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.
+-IZ. 190 is a circuit that generates an image clock and generates a pulse (approximately 8 MHz>) corresponding to the minimum modulation unit of a laser beam, 1 dot. 191 is a circuit for serially converting print data in bytes (8 bits) received from the interface circuit. control counter, 192
211 is a multiplexer that selects between 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; , 213 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;
215 is a decoder for generating a signal for controlling the test pattern generation circuit. 226, 227, and 228 are flip-flops for synchronizing print data and shadow data sending timings.

Here, the details of the counters 187 and 188 will be explained. A counter 275 determines the timing for laser beam correction for each line (horizontal scanning line), counts based on the reference clock signal 853, and generates a sample signal 375 used for light amount correction and line start. 276 is a counter for determining the horizontal recording start position, which is counted based on the Q7 output (video first dot unit signal) S83 from the control counter 191 and outputs a 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 883, and outputs a write margin signal S85 indicating the data writing end position. Reference numeral 278 is a counter for positioning the start of recording in the vertical direction, and the count is based on the output of the gate 198 which uses the input/output port 186 to output the leading edge position of the paper (page top) signal ff1s74 and the Q output of the flip-flop 204. and generates a page top count output 876.

Numeral 279 is a vertical recording end positioning counter which counts based on the output of gate 198 and outputs page end count signal 877 as described above. 280
A vertical test pattern control counter performs counting based on the Q output of the flip 70 knob 240 and outputs a test pattern control signal S79.

FIG. 26 shows the interface circuit 12 in FIG.
2 is a detailed circuit diagram of No. 2. In FIG. 26, 263 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 Inter 7Ace data bus 859. Reference numeral 266 indicates a decoder for the data selection signal S60 that specifies data on the data bus S59, and 269 indicates a control circuit for the BUSY signal that controls the data sending timing to the data control section 2 when receiving command data and print data.

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 the data bus 859.
Data on the data bus 859 is selected by a combination of two signals C0M and ID5TA. 861 is I PRD
A signal indicating that the print control unit 100 is in a ready state at Y.

S62 is IPREQ, a signal that allows the data control unit 2 to send the print start signal IPRNT, and S63 is IPE
Upon receiving this signal at ND, the data control section 2 side stops sending out the print data.

864 is IH8YN, a request signal to send one line of print data, S65 is IPRNT, a print start command signal, S3
0 is a strobe signal for commands and print data, abbreviated as l.
5TB, 866 is IBSY and the strobe signal 830
This is a signal that permits transmission of the status data and permission for the data control unit 2 to read the status data.

Commands and print data are sent to the receiver/receiver 2
65 is output to the output line S72 when the status identification signal S68 is OFF. Data on output line S72 is transferred to data latch 26 by strobe signal 830.
It is latched to 4. In the case of command data, it is latched to the input/output port 263, and after identifying the command, the specified operation of the command is executed. In the case of print data, it is sent to the print data write control circuit from the output line S59. Also, the status data is sent as follows. By receiving a status request command on the print control unit 100 side, the status contents corresponding to the command are set in the status data output 871 of the input/output capos 1 to 263. The set status data S71 is input to the transceiver/receiver 265. The input data is the status identification signal 86
8 is ON, it is output onto the data bus 859.

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 save 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, MF1-9 are manual feed mode designation commands, 78M1-4 are top/bottom margin designation commands that designate 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 status indicates that the button has been pressed, the VSYNC request indicates that the print control unit 100 has received a command to start printing and is ready to receive print data, and the manual feed status indicates that the paper feed mode is manual feed mode. The upper/lower cassette status indicates the status of the selected cassette in the cassette feeding mode, and the top/bottom margins are the top/bottom margins selected by the top/bottom margin commands (78M1 to 78M4). status, cassette size (
(upper row) and cassette size (lower row) indicate the size code of the installed cassette.Status 6Test/Maintenance indicates that the test/maintenance status is in progress.Data resend request indicates that reprinting is required due to a jam, etc. During wait, the status indicates that the printer is in a warm-up state of the fixing unit. During power save, the status indicates that the printer is in power save mode by the power save command (PSON). Operator call indicates that an operator call factor of status 4 has occurred. Serviceman call indicates that a serviceman call factor of status 5 has occurred. Tray full indicates that there are more than a specified number of sheets in the paper output tray and the tray is full. Toner bag replacement indicates that the toner pack is full of toner. Paper jam indicates that paper has jammed inside the machine. No Toner indicates that there is no more toner in the toner hopper. Cover open indicates that the front door is not closed. A timing error indicates that there was a problem in transferring print data. A fixing device failure indicates that there is an abnormality in the fixing device, such as a heater disconnection or a temperature fuse out. A laser failure indicates that the laser diode does not reach its specified power or that the beam detector is unable to detect the beam. Scan motor failure indicates that the scan motor does not reach the specified rotation speed even after a certain period of time has elapsed since startup, or that the scan motor deviates from the specified rotation speed for some reason after reaching the specified rotation 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 0 by the next surface of the polygon mirror 313. Begin beam scanning. 418 indicates the 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 indicates the data writing start point of the same A3 size paper, and 422 similarly indicates the data writing end point.

423 is the left end surface of paper size A6, 424 is the right end surface, 425 is the data writing start point of the same size, 42
Similarly, 6 represents the end point of data writing. Also 4
27 represents the center point of the paper.

d4 is the distance from the beam scanning 418 to the A3 size writing start point, d5 is the same < distance to the A6 size writing start point, d6 is the same, same < distance to the A6 size writing end point 426, d7 is the distance Each represents the distance to the writing end point of A3 size. d8 represents the distance from the beam detection point 418 to the right end surface 420 of A3 size paper. Further, d3 represents the range of one scanning of the beam. (114, d9.dlo indicate the effective printing range for A3 and 80, respectively.As is clear from this drawing, the paper feed of this printer always centers around the paper center point 427, so the beam detector position 418 depends on each paper size. The starting points for printing data are different from each other, so the beam detector 346 detects the beam according to the paper size and writes data after a period of time corresponding to the distance from each writing starting point. Instead of performing such control, this printer does not use a paper edge feed 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 Although it is set to 3IIll, it is possible to change this to O.Also, printers that use conventional edge-feed conveyance usually require a margin of about 8 to 101m1, which means that a fairly large portion of the paper will not be printed. There is a drawback.

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 end point of A3 size data writing. 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 I PRDYO (861
) becomes printable.

At the same time, the print start signal IpREQo (862) becomes active. Next, the laser enable signal LDON1
(S49) rises to 1'. This signal 849 turns on transistor 258 in FIG. At this time,
The data flip-flops 226 to 228 in FIG. 25 are not set, so the print data signal 847 and the shadow signal 848 are both "0".The laser enable 849 is "1" and the print data is O. , since the shadow signal 848 is O', the gate 24 in FIG.
6 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 a laser ready signal LRDYI (843) is generated. Next, a sample signal SMPTO (875) is generated from the counter 275 in synchronization with the horizontal synchronization signal 1-1sYO (854). This signal S75 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 the light amount correction for each line is performed. PTCTO (876) is the counter that determines the leading edge of the paper (page top counter)
The output signal, PECTO (877), is the output signal of the counter (page end counter) that determines the end position of the paper.When the timing for writing the image is reached, the 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 (873) appears and from that point H8YNCi77
Start counting the lines. In the same way, specify how many lines to write from that position (end position). In order to be able to change this specified value, a top margin 920 and a hot margin nE are provided. When the above specification is made, the PT is set before the leading edge of the paper as soon as VSYNC arrives.
An OP signal is output. For example, if a margin of 5II1m is required, count the number of lines including that margin.

If the top value is 110l1, data corresponding to that amount 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 starts, and when the count is finished, it starts up. Game 1'-2011' in Figure 25 is where you decide where to write in this way. LSTO (S78) is the Q output of flip-flop 204 for synchronization and is set by -ISYNC and reset when the sample timer signal rises.

This reset line is connected to the LDON signal (849
), and the reset line normally does not work, but a reset is forced. Upon reset, the Q output of the flip-flop 204 is generated, and the clock generation circuit 190 operates to count the clocks from the oscillator 189. This clock generation circuit 190 is an oscillator 189
The clock from the line is divided by four, and a bit-by-bit signal is output only while the line start signal LST is set. This output has two types of signals S82 and 8 with different phases.
It's now 87. As a result, synchronization for -lines is achieved. VDATl is the print data signal (847),
The signal is output as serial data by the operation of the /S conversion shift register 210. That is, the P/S conversion shift register 210 receives the signal 882 from the clock generation circuit 190.
However, when the load signal is not applied, the output 886 is O' (no laser writing),
When the load signal 888 is input, data D5 to DI2 are 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 where you actually want to 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).
The data is 69 in Figure 29. dlo) and a write margin counter 277 (data are dll and d12 in FIG. 29). In this case, the set defines the distance between the left and right sides based on the center of the paper. When the LST signal (87B) is output in synchronization with the H8YNC signal, the flip-flop 196 is set, which causes the gate 198 to flicker and the counter 276 to start 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 right margin NRm, 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, and the gate 1
99 determines the horizontal direction, so both gate outputs are (
It will be written at the point when 1, 1>. At this timing, the load signal is output, and the data 886 from the shift register 210 is serially converted and sent.

Line memory out signal LMOT (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 flip 70 knob 2.
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 DOUT of the line memory 213 or 214 is alternately read out. line memory 213
．． The writing timing to 214 is also the gate 217.21.
8 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 (S81) will be explained with reference to FIG. 43 as well.

In this type of recording device, if the laser is not emitted over the entire axial direction of the photoreceptor 301, for example, a small size paper (such as B5 or A4 paper 458 shown in FIG. 43) In many cases, printing is performed only on the paper, and as a result, toner and the like do not adhere to the area near both ends that are not used. Further, even if the paper is of a large size (for example, the paper 461 in FIG. 43), there is an unused area, and even if the paper is of a small size, the used area is within the shaded area 459). If an area where toner does not adhere for a long period of time is provided in this way, 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 LDAONI (S81) is generated immediately after printing for one sheet of paper is completed, and within this generation period, the print data signal VDATI
(847) is forcibly applied, and by this operation, lines (images) 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. The above drawbacks have been eliminated. In this case, the timing for writing line data is the data LDAT one step before the final stage data LDATn in the data of the line memory out signal LMOT1 (880).
The signal is generated when a predetermined time tx has elapsed from the falling edge of n-1. Note that such lines are not necessarily drawn periodically after each sheet of paper has been printed, but are drawn on a lot-by-lot basis (for example, every 10 sheets or 100 sheets).
You may also set it so that it is written for each page).

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). do.

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 7-lip 70-tubes 2.
26 to 228 and the gate 231 on the output side thereof. Among them, flip-flop 227 is 'm7'
For determining shadows based on level changes in the i direction (line direction), the flip 70 knob 228 is used in the vertical direction (vertical direction).
This contributes to shadow discrimination based on changes in the level of the shadow. That is, if the serial data to be written is read from the line memory 213 and sets the flip-flop 226, the data in the previous line direction is stored in the 7-lip flop 227, so the current data is set to 0', for example. When the previous data is "1", the shadow signal 848 is output.Similarly, the data of the previous line and the data of the current line are connected to the gate 2.
For example, when the data of the current line is "O" and the data at the same horizontal position of the previous line is 1', the flip 70 knob is set and a shadow signal is generated. A shadow signal is also generated when .
1 (S48).

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 character "謹" is 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.
T1. ．． Characteristic diagram 01 shows the relationship between the surface potential of the photoreceptor and exposure energy in the upper left area of the figure. Characteristic diagrams R1 and R2 show the relationship between the exposure position and the surface potential in the upper right area of the figure.
are shown respectively. In this figure, among the characters in Figs. 33 and 34, "8" in the X direction and "1" in the Y direction.
4 to 21''. As shown in FIG. 33, the characteristics PATI and R1 of the pattern shown and the third
The characteristics PAT2 and R2 of the patterns shown in FIG. 4 are different. In particular, regarding the development characteristics, it can be seen that at a certain level of development, the width D2 of R2 in FIG. 34 is larger than the width D1 of R1 in FIG. FIG. 35 is a characteristic diagram showing the relationship between the exposure position and the exposure energy. The energy of P(ON) during laser irradiation is, for example, 6 mw, and the energy of P(SH
) is, for example, 4nlW.

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. The third intensity located at (
Recording is performed using a halftone beam,
Determination of this specific relationship can be carried out by, for example, assuming that beam scanning is performed sequentially for each horizontal line. (b) determining that the recorded data changes to data that does not contribute to character formation, and scanning the unintentionally recorded data portion immediately after the change with a beam of a third intensity; and (b) scanning the current line in the horizontal line. The data is compared with the data of the previous line in the vertical direction corresponding to that position, and as in (a) above, when significant recorded data changes to unintentionally recorded data, the unintentionally recorded part immediately after the change is scanning with a beam with an intensity of .

Note that when adding the shadow, it may be applied regardless of the type of recorded information (for example, text information and image information), but
It is preferable to use this method only when dealing with textual information. In this case, as shown in the flowchart in FIG. 55 (A), the microprocessor determines whether the flow is "Shadow" or not. If it is something (for example, image information), I disable "shadow" and let it do it automatically. The command in this case is rsONF shadow 0N10F shown in Figure 27.
It is FJ. Or on the panel part [Shadow 0N10
An FFJ switch may be provided so that the operator can select it arbitrarily.

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 print quality of one dot line is increased, the print 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 of the charging high-voltage power supply circuit 160, and this shows a high-voltage electric 1ON10FF 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 charger 304; a current/voltage conversion circuit 450 that inputs the current flowing to the charger 304 and converts it into a voltage;
The operational amplifier 449 has one input as the output of the current/voltage conversion circuit 450 and the other input as the output of the control reference voltage generation circuit 448. The control reference voltage generation circuit 448 is controlled by an analog control signal 836 to output 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 is generated based on this, and the current of the charging charger at this time is determined. Current/
The output voltage is applied to the voltage conversion circuit 450, and the output voltage and the 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 △■O
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°C.
3 shows a characteristic diagram showing the relationship between the drum inflow current ID and the surface potential ■O, 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 800■ for the drum with characteristic 451 in FIG. ■Inflow current change amount △ID' corresponding to O'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.
The inflow current 10 can be adjusted by changing the voltage 6 to 2V, 4V, and 6V. Figure 41 shows
Analog input current (D/A converter 165 in Figure 15)
For example, if the temperature of the drum 301 is detected by the temperature sensor 342 (thermistor in FIG. 14) and the analog control signal 836 is applied in response to the temperature change. good.

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
The value DAT obtained by subtracting the temperature data DT25 of the cutting drum in degrees Celsius is read. Next, the reference data DV2 at a temperature of 25℃
5 is read, DV25+'D8V 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.
o, and further read the feedback error data DΔV. Next, read the reference data DV25 at a temperature of 25°C, calculate DV25+D△V, and calculate the 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
), the control input signal 835 of the charging high-voltage power supply 160 is turned on to perform 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 ◎ 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, thereafter, the characteristics of the drum currently in use 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 defects such as fogging due to a decrease in print density, a decrease in print density, or an increase in charging potential, and it is possible to always provide clear prints. Further, in this embodiment, by inputting (external setting) information classifying the temperature characteristics of the photoreceptor, correction is performed accordingly, so that temperature correction of charging characteristics can be performed with extremely high accuracy. Therefore, variations in the temperature characteristics of the photoreceptor itself can be alleviated, 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.

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 3 is turned off.
84 is confirmed to be full (FULL), and furthermore, it is confirmed whether the mode is test print mode, maintenance mode, or replacement mode. If there is no problem, the MC relay 131 will turn on, and the fuser heater lamp 333 will turn on.
ON, the scan motor 312 turns ON and timer A (
TIMA) starts. When timer ATIMA counts a predetermined time t1, mechanical parts such as the drum motor and developer motor are turned on, and then TIMA counts a predetermined time t1.
When counting 2, the laser 344 is turned on. T.I.
When time t25 is counted by MA, it is determined whether the laser is ready or not, and if yes (Y), then TIM
When A = [26 is counted, the transfer charger, laser, developer motor, and developing sleeve bias are turned off, and further, when the time of TIMA = t 27 has passed, the drum motor, heat roller motor, static elimination lamp, and pre-transfer static elimination lamp are turned off. Become. Next, at the timing of TIMA=t29, it is determined whether the scan motor is ready or H8'YNC ready, and if YES (Y), TIMA is stopped (see FIG. 47).

Next, a determination is made as to whether it is a “treyful in status 4”,
It is determined whether the toner bag is replaced or not, and whether or not there is no toner. If the tray is full, the tray full flag is set to O' after paper is removed from the output tray, and the output tray counter is set. If you reset the toner pack and change the toner pack, the reset will be performed when the state returns to its original state.
In the case of toner replenishment, reset 1~ is performed at the stage of recovery. After passing through the above flow, it is then determined whether or not it is "power saving" in "Status 3", and if no (N), then it is determined whether "No paper" in "Status 4" is in progress. , if YES (Y), "Cassette paper out detection ON"
J or not is determined, NO (if N>, there is no paper" flag is set to 0°, and if "Fuser Ready", the [Status Waiting" flag is set to "O'). Next, IPRDYO
N, becomes IPREQON, "Pa';7-1?-7 middle"
If there is no problem, ITMA starts. When TIMA=toi, the registration motor 149 rotates in reverse, and when TIMA=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" or not, and if no (N), it is determined whether it is rIPRNT ONJ or not (Yes<Y).
If so, it becomes rlPREQ 0FFJ. Next, it is determined whether or not timer E (TIME) is in operation, and if it is in operation, it is determined that rTIIVjE=t3O, and YES (
If Y), it becomes a TIME stop and the transfer shutter 3
05. Peeling charger 306. Developer motor 41. Each of the fixing device motors 43 is turned on. r
If TIME=t 30J, TIME is stopped and the flow shifts to O (see FIG. 48).

Next, TIMA starts and plaid solenoid 158
is turned ON, and rTIMA=tIJ turns on the developer motor 41. Static elimination lamp 302. Pre-transfer static elimination lamp 303. Each of the drum motors 47 is turned on. rTIMA=
At t2J, the transfer charger 305. Fuser motor 43
becomes ON.

□ The power charger 306 turns ON when rTIMA=t3J, and then turns TIMA O' when rTIMA=t4J.
Start again from . Next, it is determined whether the cassette is in the "manual feed" mode or not, and whether the cassette is in the upper or lower tier.
After waiting until MA=t 5J, the paper feed motor 51 is reversed and lower paper is fed. Next, the laser 344 is turned on when rTIMΔ-t5J, and the charger 304 is turned on when rTIMA=t6J.

rTIMA=, Check whether laser ready is present at t7j, and if yes (Y), rV in "Status 1"
sYNc request" flag is set to 1'. Thereafter, timer B (TIMB) is started and the flow shifts to (2) (see FIG. 49).

Next, the paper feed motor 151 is stopped at rTIMA=31J,
rVsYNc command received” and select YES (Y).
If so, it is determined whether rTIMB<t32J, and if yes (Y), TIMB is stopped, the "page top" and "page end counters" start counting, and the image writing process is completed. Timer 〇, D (TIMC,
D>, TIM at rTIMA=t 34J
A stop, paper feed motor 151 is stopped. Then rTI
Mc/D=t At 35J, the registration motor 149 rotates forward, the total counter 354 turns on, and rTIMc/D-13
6" 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" is determined, and if yes (Y), an image writing end IPEND pulse is output. After that, each counter is set to +1 and "tray full", "drum replacement", and "developer replacement" are performed.

If it is "heat roller replacement", each status will be displayed. Incidentally, if the determination result of the above rVsYNc:I cloak received is NO (N), the charger 304 is turned off at rTIMB=t46, and the laser 344 is turned off at r'TIMB-t47J. Hack charger 304 OFF, rTIM
B=t 47J and laser 344. Hatari charger 3
06. Turn off the developer motor 141 and rTIM.
B=t 48J and transfer charger 305. The fuser motors 143 are turned OFF, and the drum motors 147 . Static elimination lamp 302. Turn off the pre-transfer static elimination lamps 303, rTIMB=t50"
turns off the plaid solenoid 158.

Also, in the flow of rTIMB<t 32J, -(N)
If so, then it is determined that rTIMB<t 33J, and no (
N), TIMB stop and TIMA start. After that, turn on the plaid solenoid 158 and rT
At the stage of IMA=tIj, the developer motor 141. Drum motor 147. Static elimination lamp 302. Pre-transfer static elimination lamp 3
03 is ON and 1- respectively. and rTIMΔ−t2
When J, transfer charger 305. The fixing device motor 143 is turned on, and the sharpener charger 306 of rTIMA=t3J is turned on. Next, it is determined whether rTIMA=t4J or not, and timer A is stopped by -H and restarted. The developer motor 141. Transfer charger 305. Hakrijaja 306. Each of the fixing device motors 143 is turned on. rTTMA=t5
Laser 344 is ON at J, FTIM=t6J is charging charge v304ON, rTIMA=t 7J determines whether the laser is ready or not, and if yes (Y), TIMA
(Figure 50 above).

Next, it is determined whether or not the toner full detection switch 126' is ON, and if it is ON, a display is displayed, and if it is not, it is determined whether or not the toner empty detection switch 125J is ON, and a display is performed. Next, it is determined whether it is "manual feed 1" or not, and if it is not manual feed, it is then judged that "specified cassette paper is out", and if there is no paper, a message to that effect is displayed and the 5TPF (stop flag) is set to "1". Next, set timer E (T
IME). If the stop flag is “1”, set the 5TPF to “O” and print ready IPRD.
Turn Y off. If 5TPF is not 1, it is determined whether it is "manual feed 1" or not, and if it is "manual feed 1", TI is
ME stop, manual stop switch 328OF
F, manual feed O', TIMB stop, cassette paper out detection switch is determined to be 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 timer is in operation. Read all input information in the port input reading part. Then, the timer is stopped at rTIMC/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 register motor 149" is stopped. Then rTIME
-t After 4J, it is determined whether "THMA is in operation" or not (this is to determine whether the next sheet of paper is to be printed). TIME if TIMEA is in operation
to stop. After that, the charger 304 is turned off at [TIME=t 41J.

rTIME=t 42J and laser 344. Hakuli Charger 306. Each developer motor 141 is turned off. Transfer charger 305 with rTIME=t 43J
．． Turn off each fuser motor 143, rTIME=
At t44J, the drum motor 147 and the static elimination lamp 302.
The pre-transfer static elimination lamps 303 are each turned off (see FIG. 52).

FTIME=t 45J and plaid solenoid 158O
FF, TIME stop, determination of whether "Fuser temperature is normal" or not, determination of "Fuser temperature fuse stage", "Scan motor 312 ready", and "Door switch 129 OFF" are determined, depending on each status. , various processes are performed.

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 or not there is a "parity error", and if it is an error, the [Status DATA81J flag becomes "1", indicating an "illegal command error". If it is not a “parity error”, the “status request” is SR1
-6 is determined, and when 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 the "Top/Bottom Margin" is applied, and if so, "Top/Bottom Margin" is determined.
"Bottom Margin" is specified and "Status Set" is set to 1.
', and one of rDATA21-11 is specified. If it is not "Top/Bottom Margin", it is determined whether "manual feed designation" is specified, 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 is 1'.
Then, in status 4, the flow shifts to the paper out flag becoming 0'. 1 If the manual feed is not specified, it is determined whether or not the cassette is specified, and if it is the cassette, the upper/lower display paper size is displayed, the paper size register is set, and the manual feed status is changed. The status becomes 1, and the DTA41 flag is set to ``O''. It is determined whether there is no paper in the cassette, and if there is no paper, the flag is set to 1.
'. If the cassette is not specified, it is determined whether the [select lamp is lit] or not, and it is determined whether the online select lamp (specified by an external device, for example, the host side) is lit. If so, the select lamp is lit. If the select lamp is not lit, it is determined whether the select lamp is off. If YES, the select lamp is turned off. 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. 55(A), and if "power save" is in progress, the scan motor 312 is turned off.

The fuser is controlled to the power save temperature, [Status 3 power save flag 1], and when the power save is canceled, the scan motor 312ON1 is controlled to the fuser normal temperature, [Status 3 power save 7 lag 0]
], 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 5III or not, and if the result is NO (N), the top/bottom margin change table data D2 is read. Next, the calculation of top margin table data D1+margin change table data D2 is performed, and the contents of the top margin adjustment switch (442 in FIG. 14) are read. Next, the top margin adjustment table data D3 corresponding to the switch is read, 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 it is determined whether the top/bottom margin designation is 5 mm or not. If NO (N), the top/bottom margin change table data D2 is read, and the bottom margin table data D5 and the margin change table data are read. D2 is subtracted, the contents of the top margin adjustment switch 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 of the specified paper size is read. ,cassette/
Manual feed is determined. If the cassette is selected, the upper row (
If the cassette is not in the upper stage, it becomes the lower stage, and the cassette upper/lower stage adjustment switch (Fig. 14, 44)
and reads the cassette upper/lower adjustment table data D8 corresponding to the switch. The D8 is added to or subtracted from the value of the D7, and the calculation result D9 or the 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 Fig. 14), read the switch ← the corresponding cassette/manual feed adjustment table data D10, and then set the adjustment table data to the value of D7. 010 is added and subtracted, and the calculation result D11 is sent to the light margin counter 277.
Set to .

Next, left margin table data D1 for the specified paper size
2 is read, cassette/manual feed is determined,
If it is a cassette, it is determined whether it is the upper stage (standard) or not.
If the cassette upper/lower adjustment switch 440 is pressed, the contents of the cassette upper/lower adjustment switch 440 are read, and the cassette upper/lower adjustment table data D8 corresponding to the switch is read. The data D8 is set to the value of D12. Addition and subtraction are performed, and the calculated result D13 or the data DI2 is set in the left margin counter 276. Also, in the case of manual feeding, the contents of the cassette/manual feeding adjustment switch 441 are read and the cassette/manual feeding adjustment table data DIO corresponding to the switch is set. Read the data D10 and the data D12
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 IPRNTφ (865) is output, the print start permission signal IPREQφ (862) rises.

After that, the developer motor 141 etc. are turned on, and from time 14
At the gate t8, the paper feed motor 151 operates to transport 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 t11 is the data writing period). At time t, 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 IPREQφ (S62) falls, and after time tll, the registration motor 149 continues to rotate and stops until time t12. The laser diode 344 is then 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, but 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. In addition, both of them receive the print start command IPREQ after receiving the "manual feed command".
- so that φ (S62) rises. Figure 58 is 1
Indicates 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 due to paper setting, time t
At 01m, the registration motor 149 rotates slightly in the reverse direction and stops with the leading edge of the paper added, and at the time when the "manual feed command" is issued and IPREQφ (S62) rises, the registration motor 149 rotates in the reverse direction again and moves the paper to the transfer position. It is designed to be conveyed until it stops. Therefore, it is possible to print on paper from the cassette before issuing the "1 manual feed command".

The case shown in Fig. 59 is the case where the manual field switch 326 is turned on after the "manual feed command" is issued first, paper is set in the manual guide, and in this case, the 14 registration motors are turned on after the predetermined time t01 has elapsed. is continuously rotated in reverse to convey it to the transfer position. In both cases, the manual stop switch 328 is OFF.
After F (time t 20 > time t 2 after a predetermined period has elapsed)
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.

The flow transitions from the flow shown in FIG. 47.

The contents of ■ and @ 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.
When the replacement mode is selected, the flow moves to ◎, and it is determined whether to replace the drum, replace the developer, or replace the heat roller, and set the drum characteristic number, respectively.
"Developer replacement No. set", "Heat roller N.

Non-volatile generation RΔM 1 via the test key by “Set”
' Predetermined data processing for 07 is performed.

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 described above, the present invention provides beam detection means for detecting a scanning beam directed outside the scanning area, and performs straight beam detection in which the beam detection means detects the scanning beam. Since the display is displayed, it is possible to confirm whether or not the scanning beam is being irradiated without using an expensive device such as an infrared pure.

By arranging the beam detection display outside the shield that shields the scanning beam optical path from the outside, it is possible to confirm whether or not the scanning beam is being irradiated without worrying that the visual organs will be harmed by the scanning beam. .

Furthermore, by turning on and off the beam detection display according to the output of a timer that operates in response to the detection pulse of the beam detection means, the display time can be set to an appropriate constant time.

It should be noted that the present invention can be used not only for the above-mentioned recording apparatus but also for optical scanning type apparatuses in general.

(Margin below)

[Brief explanation of drawings]

FIG. 1 is a system block diagram showing the relationship between the device and external devices in the present invention, FIG. 2 is a schematic sectional view of the print control unit (printer) in the system diagram, and FIG. 3 is the laser scanner unit in FIG. 2. FIG. 4 is a schematic diagram showing the paper feeding section in FIG. 2, FIG. 5 is a schematic diagram showing an example of the paper discharging section in FIG. 2, and FIG. 7 is an enlarged plan view of the display section in FIG. 6, FIG. 8 is a block diagram showing an example of the data control section in FIG. 1, and FIG. , FIG. 10, and FIG. 12 are respectively format diagrams of data handled by the data control section, FIG. 11 is a correspondence diagram of the areas of the recording section in the data control section and paper, and FIG.
14 is a detailed circuit diagram of each detector in FIG. 13. FIG. 15 is a block diagram showing details of the drive circuit and output elements in FIG. 13. Figure 16 is similar to Figure 13 (circuit diagram showing details of pull motor drive circuit and laser scan motor, Figure 17).
The figure is a detailed circuit diagram showing the laser modulation circuit and semiconductor laser in Figure 13, Figures 18 and 19 are characteristic diagrams showing the relationship between the semiconductor laser and the optical output, and Figure 20 is the
Time chart for explaining the operation of the circuit in Figure 7, No. 21
The figure is a detailed circuit diagram showing the beam detection circuit and beam detector in Figure 13, Figures 22 and 24 are waveform charts for explaining the operation of the circuit in Figure 21, and Figures 23 (A) and (B). )
25 is a detailed circuit diagram of the print data write control circuit in FIG. 13, FIG. 26 is a circuit diagram of the interface circuit in FIG. 13, FIG. 27 is a relationship diagram between command abbreviations and functions used in the device of the present invention, FIG. 28 is an explanatory diagram showing the contents of status used in the device of the present invention, and FIG.
FIG. 9 is a diagram showing the relationship between the beam scanning position and the data writing position on the recording photoreceptor in FIG. 3, and FIG. 30 is a plan view showing the printing area of the entire surface of the paper including the paper size in FIG. 29. Figures 31 and 32 are time charts for explaining the operation of the circuit in Figure 25, Figures 33 and 34 are print pattern diagrams printed on paper, and Figures 35 and 36 are Figures 25 and 34. 37 is a characteristic diagram showing the relationship between exposure position, exposure energy, surface potential, and exposure energy and exposure position to explain the exposure control operation in the circuit of FIG.
38 to 41 are characteristic diagrams for explaining the operation of the circuit shown in FIG. 37, and FIG. 42 is a detailed block diagram of the high-voltage power supply for charging shown in FIG. Schematic diagram showing the relationship between
44 is an explanatory diagram showing the relationship between the recording photoreceptor and paper, FIG. 44 is a modification of the paper output tray shown in FIG. 5, and FIG.
A>, (B) and FIG. 46 are detailed diagrams of data recorded in each recording device in FIG. 13, a flowchart for explanation, and FIGS. 57 to 59 are for explanation of the operation of the apparatus of the present invention. The time charts of FIGS. 61 to 63 are relationship diagrams showing display numbers and their contents in the apparatus of the present invention. 346... Beam detection means, 345.454.457... Optical path adjustment means. Figure 18 Figure 19 l5 (OFF) Ya 51 Yuyue Figure 60 Figure movement I Figure 63

Claims (3)

[Claims] (1) Beam detection means that scans a predetermined range with a beam, and is arranged at a position where the scanning beam that goes outside the predetermined range passes, and adjusting the incident optical path of the scanning beam that enters the beam detection means. 1. A beam-type scanning device, comprising: an optical path adjusting means for detecting the scanning beam; and a beam detection display is displayed when the beam detecting means is detecting the scanning beam. (2) The beam type scanning device according to claim 1, wherein the beam detection display is performed outside a shielding member that shields the scanning beam optical path from the outside. (3) The beam type according to claim 1, wherein the beam detection display is performed by an output signal of a timer that operates for a certain period of time in response to a detection pulse output from the beam detection means.