JPH02548A - Device for formation of image - Google Patents

Abstract

PURPOSE:To accurately determine the write ending position of a sheet by outputting a video clock signal which becomes the stop of an output at the write ending position of the sheet from a printing side, and stopping the output of a video data signal from a host side to the printing side on the basis of the clock signal. CONSTITUTION:Video clock signals IVCLK1, IVCLK2 synchronized with the write ending position of a sheet are output from an interface circuit 519 of a 2-color LBP 199 to a host system 500, and video data signals IVDAT1, IVDAT 2 are fed from the system 500 to the circuit 519 of the LBP 199 on the basis of the clock signal. Thus, no deviation occurs at the output end timing of the data signal from the system 500. Accordingly, the write ending position of the sheet in the LBP 199 can be accurately determined.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a printing method such as a laser printer that includes a step of scanning a laser beam to form an electrostatic latent image on a photoreceptor. The present invention relates to an image forming apparatus suitable for use in apparatuses.

(Prior Art) In the case of this type of conventional image forming apparatus, as shown in FIG. 25, for example, the printing side 1 is constituted by a printer 2, and the host side 3 is constituted by a controller 4. Then, by sending a status signal from the printer 2 to the controller 4 and sending a command from the controller 0 to the printer 2, the system status can be checked based on the system status. A command is sent to cause the printer 2 to operate 1i1Jfll.

Further, when controlling the printer 2, the printer 2 outputs a horizontal synchronization signal to the controller 4, and the controller 4 sends a video data signal to the printer 2 based on the horizontal synchronization signal.

However, when sending the video data signal from the controller 6 of the host side 5 to the printing side 1, the video data signal was sent only based on the horizontal synchronization signal output from the printing side 1. The writing end position was often inaccurate.

(Problems to be Solved by the Invention) In other words, in the case of a conventional image forming apparatus, video data indicating the end position of paper writing is simply transmitted from the host side based only on a horizontal synchronization signal output from the printing side. Since a signal is sent to the printing side, and thereby the printing side finishes writing on the paper, there is a problem that the writing end position on the paper may become inaccurate.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an image forming apparatus that can accurately determine the end position of writing on paper.

[Structure of the Invention] (Means for Solving Problems) In order to achieve the above object, the present invention is composed of a printing side and a host side that sends various data signals to the printing side. The present invention is characterized in that a video clock signal is outputted from the host side and output is stopped at the end position of paper writing, and based on this video clock signal, transmission of the video data signal from the host side to the printing side is stopped.

(Function) With this configuration, the video data signal is sent from the host side to the printing side based on the video data signal from the printing side that is synchronized with the writing end position of the paper, so the video data signal from the host side is There is no difference in the signal transmission end timing. Therefore, it is possible to accurately determine the end position of paper 1 on the printing side.

(Embodiment) FIG. 1 is a block diagram schematically showing an embodiment of an image forming blade to which the present invention is applied.

The image forming apparatus of this embodiment has two colors L constituting the printing side.
BPI 99 and host system 500 (M child computers,
(external device such as a word processor) via a transmission controller (not shown) (interface circuit, etc.). And, the two-color LBP199 is the host system 5
00 accepts two types of dot image data.
The laser beams of each tree are modulated to perform 8 writing onto the photoreceptor (image carrier), and the two types of written dot image data are independently developed and transferred onto recording paper. being done.

That is, this two-color laser beam printer (laserB
In the real print 13r (hereinafter referred to as two-color LBP) 199, a first charger 2 is provided around the photoconductor 200 as shown sequentially along the rotation direction indicated by the arrow.
01. Table 1 100 Lightning Level Sensor 202. First shoulder imager 203.
Second charger 204. Table 2 100 Lightning Level Sensor 205. Second image carrier 206. Pre-transfer charger 207, transfer charger 208.
Peeling charger 209゜Cleaner 210 and N remover 211
is arranged, and Table 1 100 Lightning Level Sensor 202
The second laser beam 310 is irradiated onto the photoreceptor 200 between the first developing device 203 and the first developing device 203, and the first B light is produced.
The second developing device 206
A laser beam 310 is irradiated to perform a second exposure.

Further, the control section of the two-color LBP of this embodiment has a block configuration as shown in Fig. 2g2.

The control unit of this two-color LBP has a CPU 501 as the control center, a ROM 502 in which a system program is stored, a ROM 503 in which a data table is stored, a RAM 504 used as a working memory, a timer 505, and an I10 data input. It basically includes an output device 506, a print data writing control circuit 513, and an interface circuit 519.

The contents of the data table stored in the ROM 503 are as shown in FIG.
data for the first color top margin υ1tIl, address (4002), (4003) data for second color top margin control, address (4004), (4005)
contains data for left margin control.

Addresses (4006) and (4007) contain bottom margin control data for paper size A3, and address (400
8) (4009) contains data for controlling the light margin of the same paper size. Below, tables corresponding to various paper sizes are similarly included up to the address (4083).

From address (4090) is data for top margin coarse adjustment, from address (4080) is data for top margin fine adjustment, from address (4000) is data for left margin coarse adjustment, from address (4100) is data for left margin fine adjustment. Data and address (4120) contain two-beam scanning length correction data, which correspond to switches 1 to n, respectively.

These margin control data, coarse adjustment data, and fine adjustment data are used as set data for a margin control counter and a binary counter of a print data write control circuit 513, which will be described later.

Address (6000) (6001) contains first development bias data for red toner, address (6002>(6002)
003) contains second developing bias data. Below is the first toner, green toner and black toner. Similarly, the second developing bias data is included up to the address (600F), and the developing bias I of the process control circuit 522, which will be described later.
Used as set data for II.

Addresses (6100) (6101) contain target surface potential table data for the first charging potential control, and
This is the reference value for C.

Addresses (6102) and (6103) contain error table data at the time of convergence, and represent the allowable control range for the target surface potential.

Addresses (6104) and (6105) contain initial control output table data, which is the set value of the first electrification charger that is output at the beginning during warming up.

Addresses (6106) and (6107) contain minimum correction table data.

Address (6108) (6109) is surface potential limit table data, address (610A>(610B) is control output upper limit table data, address (,610C)
(6100) contains control output lower limit table data, and the surface potential limit table data, the control output upper limit table data, and the control output lower limit table data are used for self-diagnosis of the control system.

Below, the table corresponding to the second charging potential control similarly includes up to address (611B). Address (6120
) contains charging potential temperature correction table data in a temperature range of 10'' from 0 to 40°C, which serves as temperature correction data for the target surface potential table data of 25°C.

A timer 505 is a general-purpose timer that generates basic timing signals for controlling paper conveyance, photoconductor rotation processes, and the like.

The input/output device 506 outputs display data to the operation display section 507, inputs various switch data, etc., inputs inputs to each detector 508 in the control section, and a motor.

Output to a drive circuit 509 that drives drive elements 510 such as clutches and solenoids, output to a drive circuit 511 that drives a laser scan motor 512 for scanning two laser beams, detection of potential sensors, temperature sensors, etc. Itll outputs the high voltage power supply 523 etc. in response to the signal input.
The input/output of the process control circuit 522 is performed.

The print data write control circuit 513 includes a first laser modulation circuit 514 that performs optical modulation of the first semiconductor laser 302 for writing image data of the first color, and a second laser modulation circuit 514 that performs optical modulation of the first semiconductor laser 302 for writing image data of the first color. A second laser conversion circuit 521 that performs optical modulation of the semiconductor laser 303 is driven and controlled to write the print data of the video image transferred from the host system 500 to a predetermined position on the photoreceptor. . At this time, the beam detector 51B using a high-speed response PIN diode detects one of the two light beams being scanned by the laser scan motor, and the beam detector 517 detects one of the two light beams being scanned by the laser scan motor. 518
A high-speed comparator digitizes the analog signal from the controller to create a horizontal synchronizing pulse, which is then sent to the print data write control circuit 513.

The interface circuit 519 connects the host system 500
It outputs status data to the host system 500 and receives command data and print data from the host system 500.

Further, a power supply device 520 is provided to supply power to each part of the control section.

Details of the main blocks in FIG. 2 will be explained below.

FIG. 4 is a diagram showing details of interface signals between the interface circuit 519 and the host system 500 in FIG. 2. In the figure, D7-Do is an 8-bit bidirectional data bus, and IDSTA is a selection signal for the data bus, and is used as a status data bus to the host system 500 or as a command data bus from the host system 500. choose whether to do so. l
5TB is a strobe signal for latching the command data in the interface circuit, and IBSY is a signal for permitting transmission of the strobe signal 15TB and for reading status data.

rH8YN1 is the horizontal synchronization signal for the first color and print data 1
Request a line to be sent.

IVCLKl is a video clock signal for the first color and requests transmission of one dot of print data.

IPENDI is the page end signal of the first color and notifies the end of the line.

The host system 500 is the IH8YNI, IVCLK
It sends out the video data signal IVDATI of the dot image data of the first color based on IPENDl, and stops sending it when IPENDl is received.

Similarly, IH8YN2 is the second color horizontal synchronization signal, IVC
LK2 is the second color video clock signal, IPEND2
is the second color page end signal, and the host system 50
0 is the video data signal IVDA of the second color dot image data based on the IH3YN2 and IVCLK2.
It transmits T2 and stops transmitting when it receives IPEND2. This video data signal IVDAT1, IVDA
T 2 Get Sent to the print data write control circuit.

The above relationship is shown in FIG.

IPRDY is a signal indicating that the two-color LBP 199 is ready, IPREQ is a signal from the host system 500.
IPRME is a prime signal that initializes the two-color 1-BP 199, and IPOW is a signal that indicates that the two-color LBP 199 is energized.

Next, details of commands and statuses used in the two-color LBP 199 are shown in FIGS. 6 and 7, respectively.

In FIG. 6, SR1 to SR7 are status request commands corresponding to statuses 1 to 7 in FIG.
is the cassette upper stage paper feed specification command, C3TL is also the lower stage specification command, VSYNC is the host system 500
A command that specifies the start of sending print data, SPl
, SP2. DPl is a command that specifies the print mode,
SP1 is a printing operation for only the first color, and SP2 is a printing operation for only the second color. DPI is a mode that specifies printing operations for both the first color and the second color. MFI to 9 each indicate a manual feed mode designation command.

In FIG. 7, during paper transport, paper is being fed 2
A status indicating that paper is being transported within the color LBP 199. A VSYNC request is a status indicating that the two-color LBPI 99 has received a command to start printing and is now ready to receive print data. For manual feed, the paper feed mode is manual feed. status, status indicating the status of the selected cassette in the cassette paper feeding mode, print mode 1st color, 2nd color,
The two colors are the status indicating the selected print mode status, cassette size (upper row) and cassette size (lower row)
are the status indicating the size code of the cassette installed in the device, toner color (first color), and toner color (second color), respectively.
Color) is the status that indicates the toner color code of the developing device installed in the device, Test/Maintenance is the status that indicates the test/maintenance state, Data resend request is the status that indicates that rain printing is required due to a jam, etc., and Wait The status inside indicates that the two-color LBP is in a warm-up state of the fixing device, and the operator call indicates that an operator call factor of status 5 has occurred. Serviceman call indicates that a serviceman call factor of status 6 has occurred. Toner bag replacement indicates that the toner bag is full of toner, no paper indicates that there is no paper in the specified cassette, and paper jam indicates that paper has jammed inside the machine. No toner of the first color indicates that there is no more toner in the first developer, and no toner of the second color indicates that no more toner exists in the second developer.

The second laser failure indicates that the second laser diode does not reach a specified output or the beam detector cannot detect the beam. The second laser failure indicates that the second laser diode does not reach a specified output. Scan motor failure indicates that the scan motor does not reach the specified number of rotations even if 12i1 is light during normal operation, or that the rotation speed deviates from the specified rotation speed for some reason after the specified rotation speed. Each position sensor failure indicates that the surface potential of the photoreceptor cannot be detected, and the number of retransmitted sheets indicates the number of sheets that need to be reprinted when the data retransmission request status occurs.

FIG. 8 is a detailed circuit diagram of the first laser modulation circuit 514, the first semiconductor laser 302, the second laser modulation circuit 521, and the second semiconductor laser 303 in FIG. , R First, the first loser modulation circuit 514 and the first semiconductor laser 302 will be explained.

In FIG. 8, 302 is a first semiconductor laser diode, which is composed of a laser diode 812a that emits light;
It consists of a monitoring photodiode 811a that monitors the output beam intensity from the laser diode.

809a is a high frequency transistor and a losser diode 8
12a is optically modulated. A resistor R29a is a current detection resistor, 810a is a transistor for passing a bias current to the first loser diode 812a, R30a is a current limiting resistor thereof, R27a is a base current limiting resistor of the transistor 810a, and 817a is an inverter. Inverter 8
The input of 1a is the first router diode enable signal LD.
ONIO is input, and when this signal becomes LOW level, the transistor 810a is turned on, and a bias current flows through the first loser diode 812a. 80
7a and 808a are high-speed analog switches for modulating the losser diode 812a, and when a voltage of 1-11GH level is applied to the gate (G) of each analog switch, the drain (D) and source ( S) becomes low resistance and becomes ON state. When a LOW level voltage is applied to the gate (G), the resistance becomes high and turns off. R21a is an analog switch 807a, 8
Short circuit protection resistance during 0N-OFF change of 08a, 813a
, 814a are the analog switches 807a, aos
This is the gate driver for a. GO2a and C03a are speed-up capacitors, and R24a and R25a are input resistances of the gate drivers 813a and 814a. 815a and 816a are EXCLIJS I VE
-OR gate, which changes depending on the output of the 2AND gate 820a. The output of the 2AND gate 820a is low when either of the two gates/inputs becomes low level.
The output of the EXCLUS rVE-OR gate 815a becomes 1-0W level, and the analog switch 807a is turned on, and the output of the EXCLUS rVE-OR gate 815a is turned on.
12a is in the ON state.

The condition that the output of the AND gate 820a becomes LOW level is that the first video data signal @IVDAT10 is LOW.
level, or when the M1 sample signal SAMPIO is at the oW level. The inputs of the 2AND gate are both l-11G)-Lebel's Tokiha, fnEEXcLL
Js rVE-OR'y''-output of 816a is LOW
level, and the analog switch 7-808a is turned to O.
N, and the losser diode 812a is turned off.

806a is an operational amplifier and constitutes a voltage follower circuit. [)01 is a Zener diode, and the output of the losser diode 812a is within the maximum rating 4
The 1MM system is in place. In addition, the resistor R19a and C○1a constitute an integrating circuit, and R20a is the capacitor C01.
This is a discharge resistor that discharges the charge of a at a constant rate.

804a is an analog switch whose gate (G) is connected to inverter 805a;
The first sample signal SAMP10 is inputted to the input of the first sample signal SAMP10.

803a is a transistor for level conversion, R22a is a base current limiting resistor of the transistor 803a, and R18a is a current limiting resistor when charging the capacitor C01a. 802a is a comparator, and this comparator has hysteresis characteristics due to the action of resistors R14a and R15a.

The resistor R14 is connected to the input side of the comparator 802a.
The output voltage of the first router monitor amplifier 801a is applied through a. 801a is a losser diode 812
This is an amplifier for the output of the photodiode 811a that detects the optical output from the photodiode 811a. Resistors R12a, R13a, V
ROla is a resistor that regulates the amplifier of the operational amplifier 801a. Therefore, by changing VROla, the amplifier of operational amplifier 801a can be changed.

R11a is a load resistor for the output of the photodiode in the first loser diode, and a voltage proportional to the output current of the photodiode 811a is obtained across the resistor R11a. Since the output current of the photodiode 811a is proportional to the optical output of the laser diode 812a, the optical output of the laser diode 812a can be adjusted by varying the volume VRO1a.

818a is a comparator for checking whether or not the first loser diode is emitting light, and the output voltage of the operational amplifier 801a is applied to the negative input. Further, a voltage divided by resistors R16a and R17a is applied to the slave side input.

Therefore, when the first loser diode 812a emits light and its output exceeds the voltage divided by the resistors R16a and R17a, the output level of the comparator 818a becomes H.
The level changes from the IGH level to the LOW level, and the Loser Ready signal LRDYIO is output.

Further, a laser light amount setting voltage is applied to one input terminal of the comparator 802a. The output of the voltage follower 819 is applied to the set voltage. The exposure adjustment volume 8 is connected to the input terminal of the voltage follower 819.
21 and resistor R31 is input, and by varying the exposure adjustment volume 821, the output voltage of the voltage follower 819 also changes.

Next, the first loser modulation circuit 514 and the second loser diode 30
The second operation will be explained. First, when the first loser diode enable signal LDON10 becomes LOW level, a bias current flows through the first loser diode 812a. Next, the first
When the sample signal SAMPI O goes to LOW level,
The analog switches 804a and 807a/fi are turned on, but since the capacitor C01a is not charged, the output of the voltage follower 806a is OV, and the modulation transistor 809a is ONL. Therefore, a current flows through the first loser diode 812a to such an extent that no light is emitted. At this time, the first photodiode 8
Since no current flows through 11a, comparator 802a
Since the output becomes LOW level and the transistor 803a is turned off, the capacitor C01a is charged through the resistors R18a and R19a. Resistors R18a, R19a, capacitor C when charging
The time constant of 01a is selected to be approximately 20 to 50 IllSeC.

If this value is very small, the response of the stabilization circuit will be too fast,
Fluctuations in the laser light output level become large. Moreover, if it is too large, the responsiveness will deteriorate and it will take time for the optical output to stabilize. By charging the capacitor C01a, the output voltage of the voltage follower 806a also gradually increases. Therefore, as the base voltage of the laser modulation transistor 809a increases, a current flows to the collector. A sum current of the bias current from the transistor 810a and the collector current from the transistor 809a flows through the first loser diode 812a, and when the sum current exceeds the threshold current of the first loser diode 812a, the diode 812
a emits light. When the first loser diode 812a emits light, the first monitor photodiode 811
A current flows through a, the voltage at the t input terminal of the operational amplifier 801A increases, and the output voltage is also an amplified value of the input voltage. The output voltage of the operational amplifier 801A is
a, when the voltage exceeds the voltage divided by R17a, the output of the comparator 818a, that is, the second loser ready signal LRD
Y10 changes from HIGH to LOW level. When the output voltage of the operational amplifier 801A becomes higher than the one input terminal voltage of the comparator 802a, that is, the set voltage of the first loser light, the output of the comparator 802a changes from LOW to HI.
The level becomes GH, the transistor 803a is turned on, and the capacitor C01a is discharged through the resistor R19a.

Therefore, the base voltage of the modulation transistor 809a also decreases, and the optical output of the first loser diode decreases. No. 1 rule
When the optical output of the diode decreases, the comparator 80
The voltage at the input terminal 2a also becomes lower than the set voltage of the first laser light ffi, and the transistor 803a becomes 0FFL again, and the capacitor C01a is charged up again through the resistors R18a and R19a. In this way, the first loser diode 8
Once the light output of the light source 12a reaches the set voltage of the first loser light m, it then reaches the comparator 80 near the set voltage of the first loser light m.
2a is slowly turned ON and OFF repeatedly, and the optical output of the first loser diode 812a becomes stable.

When the CPU 501 confirms that the first loser ready signal LRDY10 has become LOW level via the I10 port, it starts the operation of a sample timer, which will be described later, and outputs the first sample signal SAM every line outside the print area.
P10 is set to LOW level for a certain period of time, and the analog switch 8048 is turned on.

Turn on 807a to stabilize the amount of laser light.

Next, when the two-color LBP 99 becomes ready for printing and the first video data signal VDAT10 is sent from the host system 500, the first video data signal VDATIO
The analog switches 807a and 808a alternately turn ON and OFF in response to
The first loser diode 812a is modulated by a, and dot image data is written onto the photoreceptor 200.

The second laser modulation circuit 514 and the first semiconductor laser 30
2 has been described in detail, the second laser modulation circuit 521
The second semiconductor laser 303 also has a similar configuration, but the second semiconductor laser 303 has a similar configuration.
The output of the voltage follower 819 is applied to the light amount setting voltage of the laser diode 812b, that is, the input terminal of the comparator 802bk-. Therefore, by varying the exposure adjustment volume 821, the output voltage of the voltage follower 819 also changes, so the comparator 8
One input terminal voltage of 02a and 802b changes simultaneously. Therefore, the optical output of the first loser diode 812a and the second
The light output of the laser diode 812b is adjusted to the exposure volume 82.
By making 1 variable, they can be adjusted at the same time.

FIG. 9 is a detailed circuit diagram of the beam detection circuit 517 and beam detector 518 shown in FIG. In Figure 9,
518 is a beam detector and has a very fast response PIN
It uses a diode.

Furthermore, this beam detector 518 serves as a reference pulse when writing print data onto the photoreceptor 200, and the generation position of this pulse must always be stable.

The anode side of the beam detector 518 is connected to one input terminal of a high speed comparator 825 through a load resistor R41 and a resistor R44. Also, the + of the high-speed comparator 825
A voltage divided by resistors R42 and R43 is applied to the side input terminal through R45. Further, a capacitor C10 for noise removal is connected in parallel to the resistor R43. In addition, R46 is designed to have hysteresis characteristics.
The positive feedback resistor C11 is a feedback capacitor for applying feedback at high speed to improve the output waveform.

Next, the operation will be explained. When the laser beam passes over the beam detector 518 at high speed, a pulse current flows through the beam detector 518, and a positive pulse voltage is generated at one input terminal of the comparator 825.

This pulse voltage is compared with the voltage at the + side input terminal of the comparator 825, and the comparator 825 outputs a negative pulse H8YO.

FIG. 10 is a diagram showing a one-time scan range of the laser beam on the photoreceptor 200 and the positional relationship of beam detection positions, data writing positions, etc. within the range.

In Fig. 10, 900 is the beam scanning start point, 901 is the beam scanning end point, and the beam that has reached the beam scanning end point 901 is moved to the next surface of the polygon mirror at time BO from the beam starting point 900 to the next beam. Start. 902 indicates the beam detection starting point of the beam detector 518; 903
9 shows the left end surface of the photoreceptor, and 910 also shows the right end surface. 904 represents the left end surface of paper, 909 represents the right end surface of paper size A3, and 907 represents the right end surface of paper size 86.

905 is the data writing start point, 908 is the paper size A3
The data writing end point 906 represents the data writing end point for paper size 80.

d2 is the distance from the beam detection point 902 to the 1-include starting point,
d3 represents the distance to the A6 size writing end point and d4 represents the distance to the A3 size writing end point. Further, dl represents the range of one scan of the beam.

d5 and d6 indicate the effective printing range in 86 and A3, respectively. As can be seen from this drawing, since the paper of this printer is always fed based on the left end surface of the paper, the printing start point 905 from the beam detection device 902 is the same for each paper size. Therefore, data may be written after a period of time corresponding to the distance from the beam detector 518 detecting the beam to the writing start point.

FIG. 11 shows the paper size and print area portion of FIG. 10 not only in the horizontal direction but also in the entire paper.

In FIG. 11, 917 is the set for 6, and 918 is the ta for A3. 904,905,906°907.90
8,909 shows the same position as in FIG.

911 is the leading edge of the paper, 913 is the data writing start point in the vertical direction of the paper, 912 is the trailing edge of the A3 size paper, 916 is the A
Indicates the end point of data writing for 3 sizes. 915 represents the trailing edge of the A6 size paper, and 914 represents the data writing end point of the 〇 size.

FIG. 12 shows the print data write control circuit 51 in FIG.
FIG. 3 is a detailed circuit diagram of No. 3. This print data writing control circuit 5
The main function of 13 is a laser modulation circuit 51 for writing print data from the host system 500 into a predetermined area on the photoreceptor 200 according to the size of the paper to be printed.
Send on 4.521. Additionally, the laser modulation circuit 514.
The necessary signals are sent to the laser light output stabilization circuit of 521. It also sends timing signals necessary for sending print data to the host system 500.

In FIG. 12, 830 is a laser modulation circuit 514.5.
This is an input/output port for sending and receiving signals necessary for control within the 21 and print data write control circuit 513. The 831 is composed of a counter 1 timer that controls writing of print data, laser light output sampling, etc., and the setting of the operation mode and the preset value of the counter 1 timer can be programmably performed using the CPLI501. be.

865 is a laser light output sample timer and gate manual G6
The beam detection signal H8YD, which is the output of the beam detector circuit 517, is input to the beam detection signal H3.
The timer operation starts after YO changes from LOW to HIGH level, and the timer operation is set to end before the beam detector 518 detects the next beam.

Therefore, the timer 865 is activated every time the timing detection signal 1-ISYO is input to the gate input G6. A 1500 KHz clock is input to the clock input CK6 of the timer 865. Output S of the timer 865
MPTD is input to one of the 2OR gates 877, and the output of the 2OR gates 877 is the first sample signal SAMP.
IO, and a second loser modulation circuit 514 as the second sample signal SAMP20, respectively. 2 in the second laser modulation circuit 517
It is sent through NAND gates 886 and 887. The other input of the 2NAND gate 886 is the I10 port 8.
Loser diode enable signal LDON for output of 30
11 is input, and the first sample signal SAM is input independently.
It is now possible to prohibit P10. Similarly, the above 2
A laser diode enable signal LDONZ1 is input, and the second sample signal SAMP20 can be inhibited independently. Similarly, the other input of the 2NAND gate 887 has the second output of the I10 boat 830.
A laser diode enable signal LDON21 is input, and the second ensemble signal SAMP20 can be inhibited independently. Also, 2OR gate 877
The output laser test signal LDTS1 of the I10 port 830 is input to the other input of the first semiconductor laser 302. by setting the laser test signal LDTS1 to HIGH level. The second semiconductor laser 303 can be forced to emit light. A first laser ready signal LRDY10 and a second laser ready signal LRDY20 are input to the I10 port 830, and the first laser ready signal LRDY10 and the second laser ready signal LRDY20 are inputted to the I10 port 830. By cutting off the second laser ready signal, it is possible to check whether each laser is emitting light.

866 is a D-type F/F that generates the line start signal LST1, which is set by the beam detection signal H3YO and reset by the rise of the sample timer output SMPTO. 867 is a D-type F/F that generates a beam detection ready signal LDOT1, which is input to the I10 boat 830. The aforementioned F/Fs 866 and 867 are also reset by the output of the 2OR gate 869. The input of the 2OR gate 869 is the first . A second laser diode enable signal.

A crystal oscillator 832 serves as a reference clock for image clock pulses, and its oscillation frequency is approximately 32 MHz. 834.
835 constitutes a quaternary counter with J-KF/F,
The output of the crystal oscillator 832 is rotated by 4 minutes to generate a first video clock VCKX21 (approximately 8 MHz) corresponding to one dot, the minimum modulation unit of the laser beam.

837.838 is J-KF/ same as above 834,835
F constitutes a quaternary counter, but JKF/F837
An n-bit binary counter 845 is input to J- of
A carry-out output CO is inputted via an inverter 846.

For J-KF/F834, 835, 837, and 838, when the input to J- is high (HIG), its Q output performs a toggle operation in synchronization with the clock input CK, and the input to J- is low
When the Q output reaches the OW level, the toggle operation is interrupted. As a result, the Q output second video cloak signal @VCKY21 of the J-KF/F838 in the subsequent stage is 15/1 when the pulse interval during normal operation is "1", and when the carry-out output CO of the n-bit binary counter 845 is generated. 4J, which means that it has been extended by 1/4 clock. The main power Qo-Qn of the n-bit latch 847 is connected to the preset inputs DO to Qn of the n-bit binary counter 845, and the set value is determined by the CPU 50.
1 allows you to set a value according to [)ip-sw, etc. The above setting value is for one line (LSTl is HIGH)
The n-bit binary counter 845
This is to set the carry-out number of "5/4" clock generation as a result.

Inverter 839. The shift register 840°2NOR gates 841 and 842 are connected to the n-bit binary counter 8.
This circuit provides a predetermined operation to 45.

The second video clock signal VCKY21 has a scanning length of two laser beams 1. It is used to correct the difference between the two. In this case, the laser beam of the driver 1, which has a long scanning length, is supplied with the first decoder signal CKX21. A second video clock signal VCK is applied to the A2 laser beam with a short scanning length.
Just specify Y21. Reference numeral 848 indicates a filleter that performs this designation using the output CHGCK of the f10 port 830.

Next, a correction method will be explained using an example. For example, if the laser beam hi1 with a long scanning length is 200 mra and the laser beam fL2 with a short scanning length is 199 mm, the difference in scanning length will be 11RI11. If the resolution is 12 lines/mm, 12 per 2400 dot clocks (200X12)
It is sufficient to extend the video clock signal @VCKY21 of the laser beam magazine 2, which has a short scanning length, by the amount of the Todd clock. Here, in one correction, the 1/4 dot clock is expanded, so the 1/4 dot clock correction is performed 12x4=48 times during the 2400 dot clocks.

Therefore, in the n-bit binary counter 845, the clock input CP of the n-bit binary counter is 1/
Since it is a 4-dot clock, its carryout is 9.
600 (2400x4) 4 while counting clocks
It is enough to output 8. In other words, the preset value may be set so that one carry occurs every 200 counts.

836 is a binary counter, and its Q2 output HCT31 is an 8-dot clock (approximately 1 MHz) obtained by dividing the frequency of the first video clock VCKX21 by 8. 863 is a left margin counter that sets the data writing start point from the beam scanning start point.

864 is a write margin counter that sets the data writing end point from the beam scanning start point. The line start signal LSTI is applied to the gate input G4 of the left margin counter 863 and the gate input G5 of the left margin counter 864.

Clock input CK of the left margin counter 863
4 and the clock input CK of the write margin counter
The 8-dot clock HCT31 is input to 5. Both counters account for fluctuations in the data writing start point and data writing end point due to mechanical installation errors of the beam detector 518.
This and the beam can be corrected at the same time. The correction of the error is D
If you change the settings of the counter for both swords according to the IR-8W etc., you can adjust it in 8-dot clock units. The reason for setting it in units of 8 dot clocks is that even if the data writing start position and data writing end position on the paper are shifted by 8 dots, it is within the permissible range, and furthermore, the above-mentioned error can be easily adjusted. It is. The set value of the light margin counter changes depending on the paper size.

875 is a 2AND gate, and one input is the output LMCTO of the left margin counter 863, and the other input is the output RMCTO of the right margin counter 864, which is input via the inverter 874.
The output of AND gate 875 represents the horizontal print area.

The output of the 2AND gate 875 is sent to the shift register 86.
8, it is shifted by 4 dot clocks, and the horizontal printing area signal @
HPENI is output from the Q output.

The horizontal print area signal 1-IP E N 1 is input to the CE input of the n-bit binary counter 850 and the shift register 854 . The n-bit binary counter 850 and the 2NAND gate 849. n bit latch 8
51. J-KF/F852 has a circuit configuration that can shift the data write start point to the right in 1-dot units.
The output of F/F852 is the first horizontal printing area signal HPEN
Output BI. The n-bit binary counter 850
The preset inputs DO to Qn are used to set the number of right shifts and are connected to the output of the n-bit latch 851, and the set value can be set by the CPU 501 to a value corresponding to D1p-SW and the like. The shift register 854 and the shift register 855. The inverter 853 has a circuit configuration that shifts the horizontal print area signal HPEN1 to the right by two dot clocks, and the output of the shift register 855 outputs a second horizontal print area signal HPENAI. This is because the first horizontal print area signal HPENBI is shifted to the right by two dot clocks even at the minimum set value.

The output of AND gate 857 is a first video clock signal VC which is indicative of the first horizontal print area valve video clock signal.
In LKBI, one of the inputs of the AND gate 857 is the first horizontal print area signal @) (PENB1; the other is the Y1 output of the selector 848. The output of the AND gate 856 is the video clock of the second print area valve. One of the inputs of the AND gate 856 is the second video clock signal VCLKAI indicating the second horizontal print area signal 1''P.
ENA1. The other is the Y2 output of the selector 848.

As mentioned above, the first horizontal printing area signal 1-IPEN is a signal that allows the data writing σ■ starting point to be adjusted at the 41st position of 1 dot.
B 1 and the first clock signal VCLKB1 are used to correct errors in the scanning start points of the two laser beams. In this case, the laser of S2, which has a fast scanning start point,
M22 horizontal mark area signal 1-IPENA 1, 2nd
DR't') Dtsk signal V CL KAl is specified, and the first horizontal printing area signal HPENB1 . 1st clock signal VCLKB
It is sufficient to specify I and adjust the error d.

The selector 858 is a selector for making the specification, and is made by the output C)-IG12 of the 110 port 830.

859 to 862 are take 8 in the vertical direction (paper advancing direction)
This is a counter for setting the first data write start point and the data write end point. 859 is the first page top counter that sets the first color data write start point. 860 is the first page top counter that sets the first color data write end point. 1st page end counter, 861
is a second page top counter 862 which sets the start point of data writing for the second color. 862 is a second page end counter that sets the end point of data writing for the second color.

Gate inputs GO to G3 of each counter 859 to 862 have a page top signal PT which is the output of the I10 boat 830.
OP1 is connected. It is started by the VSYNC command.

Clock input CKo-CK of each counter 859 to 862
3 is connected to the line start signal LST1,
As a result, it is possible to count in units of one scanning line (in units of one dot). The method of setting each counter will be described later.

871 is a 2AND gate, one input is the output PTCT10 of the first page top counter 859, and the other input is the output PECT1 of the first page end counter 860.
Therefore, the output of the 2AND gate 871 becomes the first color vertical print area signal VPEN11.

873 is a 2AND gate, one input is the output PTCT20 of the second page top counter 861, and the other input is the output PECT2 of the second page end counter 862.
O is input through the inverter 872, and therefore the output of the 2ΔAND gate 873 becomes the second color vertical print area signal vPEN21.

The output PECT10 of the first page end counter and the output PECT2O of the second page end counter are input to the I10 port 830, and after the respective counting operations are completed, the first color page end signal IPENDIO and the second color page end signal IPENDIO are input to the I10 port 830.
Hesier >t' message@IPEND20 is sent to the host system 500.

878 is the first color horizontal synchronization signal I) A5YN10,
Reference numeral 879 is a ZNAND gate that sends the second color horizontal do-bright signal 1f-1sYN20 to the host system 500.

880 is the first color video clock signal rvCLKIO
, 881 is the second color video clock signal IVCLK
20 to the host system 500.

884 is a 3NA that sends the first color video data signal rVDT10 from the host system 500 to the first loser modulation circuit 514 as the first video data signal VDAT10.
It is an ND gate.

3N 885 sends the second color video data signal IVDT20 from the host system 500 to the second laser modulation circuit 521 as the second video data signal VDA20.
It is an AND gate.

888 is an inverter that sends a first loser diode enable signal LDONIO to the first loser modulation circuit 514; 8
89 is an inverter that sends a second laser diode enable signal LDON20 to the second laser modulation circuit 521.

FIG. 13 shows a timing chart of the main signals for one page in the two-color printing mode, and FIG. 14 shows a timing chart of the main signals for one line.

Next, the operation of each part that operates in response to a control command issued from the Lurie control part of the two-color L8P 199 will be described in detail according to each flowchart shown in FIGS. 15 to 24.

15 to 19 are flowcharts showing the overall operation of the two-color LBP.

FIG. 15 shows the self-diagnosis and warming-up processes of the two-color LBP 199.

In FIG. 15, the operator turns on the electric device 520eON.
Then, the system 10g stored in the ROM 502 starts, and first, the self-diagnosis process of steps A101 to AlO4 is executed, and when the door switch is ON (step A101 is negative), the door oven process (step A1
05), and the paper discharge switch is turned on, the manual stop switch is turned on, and the bus sensor is turned on to perform jam processing (step A106).

If it is not the test print mode or the maintenance mode (step 107 negative, step 108 negative), the heater lamp that heats the fixing device 221, which takes a relatively long time to reach the ready state, is turned on (step 111).
Warming-up processing is started, and then the fixing device 221
motor and scan motor 512 are turned on (step Δ112). Note that if you are in test print mode (
Step 107 Portrait>, a test print process is executed (step A109), and if it is in the maintenance mode, a maintenance process is executed (step A110).

When the scan motor 512 is turned on and becomes ready (step A113 affirmative), the blade solenoid is turned on (step A114). Note that if the scan motor 512 is not in the ready state even after 30 seconds have passed since it was turned on (step A113 negative, A115ti
(setting), failure processing for the scan motor 512 is performed (
Step 116).

After the subsequent delay processing (step 117), the drum motor of the photoreceptor 200, the developer motor 425, the clutch of the first developer 203, the clutch of the second developer 206, and the static eliminator 21
Each of the No. 1 lamps is turned on (Step 118), and through delay processing (Step 119), the No. 1 loser diode 3 is turned on (Step 118).
02, the second laser diode 303, laser test, and pre-transfer charger 208 are turned on (step △
120).

After the subsequent delay processing (step A121), if the failure of the first laser diode 302 and the second laser diode 303 is determined by the monitor (steps A122 and A123), if normal (step A122 is affirmative, step A123).
(affirmative), horizontal synchronization No. 12 HS YNC sees those beam detection ready (step Δ128). In addition,
If the first loser diode 302 is out of order (No in step 122), the first loser failure process (step Al24).
is executed, and if the second laser diode 303 is out of order (No in step 123), the second laser failure IJJ! l
! 1 process (step A125) is executed. Further, if the beam is not detected by the horizontal synchronization signal H8YNC (step 126 negative), beam detection failure processing (step A12
7) is executed.

After the subsequent delay processing (step A i 29 ), the stripping charger 209 is turned on (step A 130 ), and the delay processing (
After step A131), potential control during warming up as shown in FIG. 70 is performed (step A131).
132). Note that step A132 is a process for enabling printing as quickly as possible during the first printing.

After the subsequent delay processing (step Δ133), step A1
The process advances to steps 34 to A140. That is, step A13
4, the pre-transfer charger 207. Transfer charger 208. Each of the stripping chargers 209 is turned off. Step A136
Here, the developer motor 425, the clutch of the first developing device 203, the clutch of the second developing device 206, the first charger 201 .
Each of the second chargers 204 is turned off. Step A1
38, the drum motor of the photoreceptor 200, the static eliminator 211
, the first loser diode 302. Second laser diode 3
03. Each of the motors of the fixing device 222 is turned off. At step Δ140, the blade solenoid is turned off.

Thereafter, wait until the fixing device 221 becomes ready (step 141 is affirmative), complete the self-diagnosis and warming-up processes in steps A101 to A141, and proceed to step 16.
Proceed to a routine not shown.

FIG. 16 shows two colors 1 [3
The host system 500 reports the status of each part of the host system 500.
We accept the process of issuing a print request when the status of each part is determined to be normal.

In FIG. 16, first, a determination is obtained from the host system regarding the contents of status 5 <Proceed to step A142-A
145). That is, in step A142, it is determined whether or not to replace the toner bag. If there are six toner packs to be replaced (step A142Fj determined), the toner pack is replaced (step A146), and when the replacement is completed (step A146 affirmative, A147), the process proceeds to step Δ143. In step A143, it is determined whether or not the first color toner is out of the 0N10FF state of the empty switch of the first presenter 203. If there is no first color toner (Yes at step A143), check whether it is @2 color mode according to status 1 (Step Δ148), if it is the first color mode and 2 color printing mode (No at Step A148)
, the supply of the first color toner to the first developing device 203 is completed (go to step 149, affirmative), A150, and the process proceeds to step Δ144. In addition, if it is the second color mode (Step A148 Portrait, Step A149. Skip Step A150 and proceed to A144. In Step A144, the second developing device 2
0N10FF of the empty switch 06 determines whether or not there is no second color toner. No second color toner
) (Yes at step A144), the status 1 indicates whether the first color is [-] or not (step A151).
), if it is necessary in the second color mode and two-color printing mode (No in step A151), the second color toner supply to the second developing device 20G is completed (Yes in step A152, A153), and the process proceeds to step 145. If the mode is the first color mode (go to step 151), step Δ152 and A153 are skipped and the process proceeds to step 145.

In this way, if there is no abnormality in the toner status of the first developing device 203 and the second developing device 206, reception of commands from the host system 500 is permitted. (Step A145).

If there is a command specifying the 10th printing mode (Yes at Step A154), the first color mode is set in Status 1 (Step A157), and if there is a command specifying the second printing mode (Yes at Step A155). ,
The second color mode is set for status 1 (step A158).

Furthermore, if there is a command specifying the two-color printing mode (step A1561), the two-color mode is set in status 1 (step A159).

Then, in the subsequent step A160, when the process of turning IPRDY ON and IPREQ ON is executed, the process of determining whether IPRNT has been turned ON is performed in the subsequent step A161, and if the IPRNT is turned ON or not, it remains O"F. If there is (no in step A161), the process returns to step A142, and if it is turned on (step Al61t6 fixed), the print request is turned off (step Δ162) and the process proceeds to the print processing after the routine shown in FIG.

In FIG. 17, steps A163 to A17
4, a process similar to the warming-up process routine is executed.

In the following step A177, it is determined based on the status 1 whether the mode is the second color mode or not. If it is not the second color mode (No in step A177), the clutch of the first developing device 203 is turned on and the first developing device 203 is driven (step A178), and the process advances to step A179. If it is the second color mode (step A177 affirmative), step △17
8 and proceeds to step A179.

In step A179, it is checked based on status 1 whether the mode is the first color mode. If the mode is not the first color mode (No in step A179), the clutch of the second developing device 206 is turned on and the second developing device 206 is driven (step Δ1
80), proceed to step A181. If it is the second color mode, step Δ180 is skipped and the process proceeds to step A181.

In step A181, the bias table data regarding the toner color of the first developing device 203 is read, and in the subsequent step A182, the read bias table data is set in the D/A converter 578, and in the subsequent step A1
In step A183, bias table data regarding the toner color of the second developing device 206 is read, and in the subsequent step A184, a process of setting the read bias table data in the D/A converter 584 is executed.

After the subsequent delay processing (step A185), potential control before first printing as shown in FIG. 22 is executed (
Step A186).

In the following step A187, it is checked based on status 1 whether the mode is the second color mode. If it is not the second color mode (No in step A187), the developing bias 409 of the first developing device 203 is ONI.

(Step A188), and the process advances to step A190.

If it is the second color mode (Yes at step 187), step A188 is skipped and the process proceeds to step A190, and second charging potential control is performed as shown in FIG. 22 (step A189).

In step 8 191 following the delay processing in step 190, it is checked based on status 1 whether or not the mode is the first color mode. If it is not the first color mode (No in step A191), the developing bias 409 of the second imager 206 is set to ONL,
, (step A192), the process proceeds to step A194. If it is the first color mode (Yes at step A191), the process skips step 192 and proceeds to step A194, and the first charging potential control is performed as shown in FIG. 22 (step A193).

In step A194, it is determined whether the paper feed cassette is in the upper or lower stage based on the status 1. If it is determined that the paper feed cassette is in the upper stage, the paper feed motor is driven in normal rotation to perform upper stage paper feeding (step A195). ), step A
199, and after the delay processing in step A208, the paper feed motor is turned off (step A209). If it is determined that the paper is in the lower stage, step A195 is skipped, and after delay processing (step A196), the paper feed motor is reversed to perform lower paper feeding (step A197).
, the process proceeds to step A199, and after the delay processing in step A208, the paper feed motor is turned off (step A2
09).

In step 199, it is checked based on status 1 whether the mode is the second color mode, and if it is not the second color mode (No in step A199), the process proceeds to step A202 after the delay processing in step A200. If it is the second color mode (Yes at step A199), the process proceeds to step A202 after the delay processing at step A201.

In step A202, beam detection ready is detected using the horizontal synchronizing signal H8YNC, and the process proceeds to step A204. Note that if beam detection is not ready (No in step A202), beam detection failure processing is executed.

In step A204, as shown in FIGS. 20 and 21, the base counter, page end counter,
A left margin counter, a right margin counter, and a two-beam scanning length correction value are set.

In the following step A205, a vSYNC request with status 1 is set, and the process waits for a VSYNC command (
Step A206), from the host system 500 to the VS
When the YNC command is sent, the VSYNC request is reset (step A207).

In the subsequent step A210 of FIG. 18, the top/bottom counter starts counting and image writing starts.
Based on status 1, it is confirmed whether the mode is two-color printing mode (step Δ211). Then, if it is the first color mode and the second color mode (step A211 negative), the process advances to step Δ213, and if it is the two color mode (step A211 affirmative), the process advances to step A213 and the seventh color mode.
The first charging potential control as shown in FIG. 0 is repeated five times (step A212).

In the following step 213, the second
Check whether it is in color mode. If it is not the first color mode (No in step 213), the process proceeds to step 216 after the delay process in step 214; if it is the second color toner (
After step 213 (portrait) and delay processing in step A215, the process proceeds to step 216.

In step 216, when the registration motor is turned on and the total counter is turned on, delay processing (A217) I
The total counter is turned OFF and the process proceeds to step A221, and after the execution is delayed by the paper size (A219),
The registration motor is turned off (step A220>).

In step A221, it is checked again whether the mode is the second color mode. If it is not the second color mode (step A22
1 negative), when the end of the first page is detected (step A222 affirmative), the first color and both image country ends and the IP
ENDI is pulsed (step A223), and the process advances to step A224. In step A224, it is checked whether the mode is the first color mode.

If status 1 is the first color mode (step A22
If the first color toner is present in the first developing device 203 (No in step A231), the second color toner is present in the second developing device 206.
Even if there is no color toner (step A238 affirmative), the 19th
As shown in the figure, the print request IPREQ is turned on (step A248>).

At this time, when there is no first color toner in the first developing device 203 (step A231 affirmative) and there is no second color toner in the second developing device 20G (step A232 affirmative), the print ready IPRDY is displayed as shown in FIG. is turned off (
Step A252).

Furthermore, even if there is no first color toner in the first developing device 203 (Sten 7A231M fixed), there is second color toner in the second BlaI'24206 (step A232 negative), and either the first color or the second color If both are the same color, (step A
233ti setting), when the second color printing mode setting command is issued (step A234 affirmative), the first developing device 2
03 developing bias 409 and its clutch are turned off (step Δ235), the charging potential υJ12IIlfi of the first charger 201 is stopped, and this first charger 201
is turned off (step A236), the second color mode of status 1 is set (step A237), and the print request fPREQ is turned on (step A24).
8).

On the other hand, when there is toner of the first color in the first developing device 203 (No in step A231) and there is toner of the second color in the second developing device 206 (No in step A238), a command for specifying the second color printing mode is issued. If there is (step A239
affirmative), the phenomenon bias 409 of the first developing device 203 and its clutch are turned off (step A235), and the first developing device 203 is turned off (step A235).
When the charge potential control of the charger 201 is stopped, this first charger 2
01 is turned off (step A236), and status 1
The second color mode setting is executed (step A237).
, print request TPI” (EQ is turned ON (step A248).

On the other hand, when it is determined in step A221 that the mode is the second color mode, and it is determined that the mode is not the first color mode in step A224, when the second page end is detected (step A
225 Portrait, 2nd color image is finished and IPEND
2 is output as a pulse (step A226), and the process advances to step A227.

If status 1 is the second color mode (step A22
7 (Yes), even if there is no second color toner in the second developing device 206 (step A240 direction determination), there is first color toner in the first developing device 203 (step A241 negative), and the first color and If both of the two colors are the same color (step A242
(Yes), when the command specifying the first color printing mode is issued (Yes at Step A243), the Kawaden bias 409 of the second developing device 206 and its clutch are turned off (Step 244), and the second charger 204 is turned off. The charging potential control is stopped and this 27th FI electric appliance 204 is turned off (
Step A245a>, after the first color mode of status 1 is set (step A245b), the print request IPREQ is turned on as shown in FIG.
step Δ248).

Also, in step A227, status 1 is the second
If the mode is other than the color mode, it is determined in step A228 whether the first color toner is out based on the status 5, and in step A22, it is determined based on the status 5 whether or not the second color toner is out. And step A22B
, A229, if there is no toner, the print ready IPRDY is turned OFF as shown in FIG. 67 (step Δ252).

Also, if there are first and second color toners (step A
228 negative, 229 negative), and at the same time proceed to step A248, the second band NT 1st place υ1i1 as shown in FIG.
] twice (step A230).
In the routine from 221 to △248, step A23
By omitting the determinations in step 2 and step 242, even if the toners in the first developing device 203 and the second developing device 206 are not the same color, continuous development can be performed by switching the developing device.

In FIG. 19, after the process of turning on the print request IPREQ in step A248, IPRNT is turned on.
Judgment process to hold for 5 seconds (steps A249, A250)
is executed and IPRNT turns ON (step A2
49M), the print request IPREQ is turned off <Step A251>, and it is determined whether the print mode has been changed (Step A266>).

If the print [-] code has been changed (step A266
Yes), return to step A177, and step A177~
During step A194, check the status 1 and
The developing device 203 or the second developing device 206 is made ready for development.

If the print mode has not been changed, skip step A26.
6 negative), return to step A194, and step A177
The processing from step A193 to step A193 is omitted.

However, in any printing mode, step A
Since the processes 142 to A174 are repeated without performing them, the recording operation continues without temporarily stopping the two-color LBP 199.

In contrast, when the judgment process of waiting for IPRNT ON for 5 seconds (steps A249 and A250) is executed,
If 5 seconds have elapsed (step A250), after the stop processing in steps A253 to A265, the process returns to step A142 and enters the special effects state where it waits for a command from the host system 500.

Also, if the print ready l PRDY is OFF, step A252), the print operation is not necessary.
After the stop processing in steps A253 to A265, the process returns to step A142 and enters a standby state for a command from the host system 500.

FIGS. 20 and 21 show step △204 in FIG. 17.
3 is a flowchart showing the processing of FIG.

In the subroutines shown in FIGS. 20 and 21,
The process of coarsely adjusting and setting the top margin from step 8101 to step 8107, the process of finely adjusting and setting the top margin from step 8114 to step B119, the process of finely adjusting the bottom margin from step B120 to step B123, and step B124 ~ Step 8128 to coarsely adjust the left margin; step 8129 to step B131 to coarsely adjust the right margin; step 8132 to step B136 to finely adjust the right margin; and step 8137 to step B136 to finely adjust the right margin. The processing is roughly divided into two beam scanning correction set processing of B141, and the details thereof are as shown in the figure.

That is, in the process of coarsely adjusting and setting the top margin in steps 3101 to 107, after reading the first color top margin table data D1 (step B101),
Read top margin coarse adjustment switch (step B1
02), and reads the top margin coarse adjustment table data D2 corresponding to the switch (step B103).
.

In the following step B104, the top margin coarse adjustment table data D2 is added or subtracted from the value of the first color top margin table data D1 to obtain a calculation result D3.

In the following step B105, if status 1 is not the two-color mode (step B105 negative), the calculation result D3 is used as the first color mode.
Set it in the page top counter 859 (step 8
106), Steps BIO8-B] Proceed to the routine for coarsely adjusting and setting the bottom margin in step BIO13. Also, if status 1 is two-color mode (determined in step B105),
The calculation result D3 is set in the second page top counter 861 (step B107), and the process is also performed in step 8108.
- Proceed to routine B113.

After reading the bottom margin table data D4 of the specified paper size in step 8108, in the following step 8109, the first color top margin table data D1 is added to the bottom margin tilt data D4 to obtain a calculation result D5.

In the subsequent step B110, the margin coarse adjustment table data D2 is added to the value of the calculation result D5, and the calculation result D6 is obtained.
get.

In the following step B111, if step 1 is not the second color mode (step B111 negative, the calculation result D6 is set to the first color mode).
Set the page end counter 860 (step B
113), the process advances to steps 8114 to B119, a routine for finely adjusting and setting the top margin. Further, if step 1 is the second color mode (step B111 affirmative),
Arithmetic results! f! D6 is set in the second page end counter 862 (step 13112), and step 8
Proceed to routines 114-819.

When the second color top margin table data D7 is read in step B114, the top margin fine adjustment switch is read in the subsequent step B115, and the subsequent step 811
In step 6, the top margin fine adjustment table data D8 corresponding to the switch is read.

In the following step B117, the margin coarse adjustment table data D2 is added to the value of the second color top margin table data D7.
and the fine adjustment table data D8 are added or subtracted to obtain a calculation result D9.

In the following step B118, if status 1 is not 2 colors [- (step 8118 negative), step 8120-
Proceed to the bottom margin fine adjustment set routine of 8123. Furthermore, if the status 1 is the two-color mode (step B118 affirmative), the PiJrt result D9 is set in the second page top counter 861 (step B119).
, similarly proceeds to the routine of step B120-8123.

At step 8120, the bottom margin table data D4
After adding the second color top margin table data D7 to obtain the calculation result 010, in the subsequent step B121, the margin rough adjustment table D8 is added or subtracted from the value of the calculation result 010 to obtain the calculation result 011.

If the status 1 is not the two-color mode in the subsequent step B122 (step B122 negative), steps 8124~
The program proceeds to the left margin coarse adjustment routine of 8128. Further, if the status 1 is the two-color mode (step B122 affirmative), the calculation result D11 is set in the second page end counter (step 8123), and the process similarly proceeds to the routine of steps 8124 to 8128.

In step B124, left margin table data 01
2 is read, the left margin coarse adjustment switch is read in the subsequent step B125, and the left margin coarse adjustment table data 013 corresponding to the switch is read in the subsequent step B126.

In the following step B127, the margin coarse adjustment table D13 is added or subtracted from the value of the left margin table data D12 to obtain the calculation result D14.

Continuation (When the calculation result D14 is set in the left margin counter 863 in step 8728, steps 8129 to
The process advances to B131, the light margin coarse adjustment set routine.

In step B129, the light margin table data D15 of the specified paper size is read, and in the subsequent step 8130, the coarse margin adjustment table data D13 is added or subtracted from the value of the light margin table data D15 to obtain a calculation result D16.

In the subsequent step B131, the calculation result D16 is set in the write margin counter 864, and steps 8132 to
The program proceeds to a routine for finely adjusting and setting the write margin of 8136.

Left margin y in step B132! The adjustment switch is read, and in the subsequent step B133, the left margin fine adjustment table data []17 corresponding to the switch 7.1 is read t9, and in the subsequent step B134, the table data D17 is read.
The value of is set in the n-bit latch 851.

In the subsequent step B135, the print area changeover switch is read, and in the subsequent step 8136, the I10 port 830 is set according to the print area changeover switch, and then steps 8137 to
The process advances to B141, a two-beam scanning length correction routine.

After reading the 2-beam scanning length correction switch in step B137, the scanning length correction table data D18 corresponding to the switch is read in the subsequent step 8138, and this table data 018 is transferred to the n-bit latch 84 in the subsequent step B139.
Set to 7.

In the following step 8140, the dot clock changeover switch is read, and in accordance with this dot clock changeover switch, in the subsequent step B141, r10 baud i-830 is set, and the process of step A204 shown in FIG. 17 is completed.

Figure 22 is a flow chart showing potential 1 control during warm-up and potential υ11211 of first print 6.7.
-It is a shade.

Potential control during warming up is as follows: 1. The value CHD T + of the first charging initial control output is read from the table data (step C10I), and the read value is set in the D/A converter 576 (step C102). Further, the second charging initial control output [CHDT7] is read from the table data (step C103), and the read value is set in the D/A converter 582 (step C104).

When the first charger 201 is turned on in the subsequent step ClO3, first charging potential control is executed as shown in FIGS. 23 and 24 (step C106). The subsequent delay processing (
After step C107), when the second charger 204 is turned on in step 0108, the second charging voltage level f+lI wJ is executed as shown in FIGS. 23 and 24 (step C109).

Then, step C110) increments the potential control number n.
, Steps 0105 to C111) are repeated until the potential control number n reaches 3 times, and when it is performed 3 times, the first charger 201 and the second charger 204 are turned off.
Then, in step C112, this warming-up potential υ1 is completed.

The potential tIII fit before the first print is the same unless the status 1 is in the second color mode (step D101
negative), the first charger 201 is turned on (step D1
02>, as shown in FIGS. 71 and 72, the first charged potential is executed (step D103), and if only the first color mode is present (step D104 t, jj constant), the potential before first printing is It becomes Hiiragi Y of control.

Moreover, if it is two-color mode (step D104 negative),
After the delay process (step D105), the second charger 204
is turned on, and the second charging potential control is executed as shown in FIGS. 71 and 72 (step D107), and the potential a before the first print ends.

Further, if the status 1 is the second color mode in the first step D101, only the second color mode is executed, so the second charger 204 is turned on (step D106), and as shown in FIGS. Second charging potential III
m is executed (step D107), and the potential υ1611 before the first print ends.

FIGS. 23 and 24 are flowcharts showing details of the charging potential control 15121 process.

In the rib routine according to FIGS. 23 and 24,
First, the A/D converter 593 detects the drum temperature detector 570.
is selected (step E101), and the photoreceptor 200
temperature measurement is performed (step E102), either the first charging potential control or the second charging potential control is selected (step E103), and the first band Ti potential control is selected based on the data table in the ROM 503. In this case, each process from step 0105 to step E109 is executed, and in the case where the second charging potential 11J is controlled, step E1 is executed.
Each process from step E13 to step E118 is executed.

Then, in step El10 and step E119, the first
The target surface potential data (VO81) and the second target surface potential data (VO32) are corrected, and each corresponding correction data VO31= and VO82' is increased by 1q.

In subsequent steps E111 and E120, in order to store each company obtained in steps E104 to E110 and each company obtained in steps E113 to E119 in a common register, arithmetic processing as shown in step E111 and step E120 is performed. is executed.

In the following steps E112 and E121, A
/ D converter 593 respectively sets the first potential sensor'? 202
and the second lightning level sensor 205 is selected.

Next, regardless of whether the first charging potential control or the second charging potential control is performed, each process from step E122 onwards is executed.

First, 1. A delay process is executed for a time corresponding to the travel distance between the second charger 201.204 and the first charger position sensor 202.205. The surface potential VS is measured by the second surface sensor 202, 205 (steps E122 to E123).

After the following steps, step E111 and step E
Processing is performed based on each data shown at 120.

That is, in step E124, according to the calculation formula VS≧Vos+VovAX, the read value is Vos+VoMA
Self-diagnose whether it is X or higher. If it is the above (step E124 affirmative), potential control error processing is executed. (Step E125). If it is less than (step E124 negative), the process advances to step E126.

In step E126, it is determined whether the read value is within the control range of the target value and the error table according to the formula Vs=Vos+Voz.

If not (step E126 negative), step by step check how much it deviates from the target by, for example, 200V, 100V, 50V (step El 27. El
28. El 29), fIllltlffl ΔX
The process of setting the size to be the same as, twice, four times, and six times the weight or ΔX2) is executed (step E13).
0. E131. E132. E133).

After this setting, the process proceeds to step E134, in which the charging output is set, and in the subsequent step E135, it is checked whether the charging output is larger than the maximum value, and in the subsequent step E13.
6r It is checked whether the charging output is smaller than the minimum value, and if it is too large or too small (step E135 affirmative, step E136 affirmative), potential control error processing is executed (step E137). ).

If the charging output is within the control range (step E135 negative, step E136 negative), step E1
38, it is determined whether the actual potential control target is the first charger 201 or the second charger 204.

If this determination result is the first charger 201, C1-1o
T+=C) (After setting 0 (step E139), a process of setting Cl-10T in the D/A converter 576 is executed, and the process advances to step E145.

Also, if this determination result is the second charger 204, CHo
After setting T 2 =CHD T (step E141), C)-ID is set to D/
The process of setting the A converter 582 is executed, and the process advances to step E145.

In step E145, the number of times of charging potential control is incremented, and the routine proceeds to step E146 and subsequent steps in FIG.

In other words, if the potential is controlled before the first print (step E146), the potential υr no @ several m is set three times (step E151 fi fixed), and the non-convergence due to potential control ends, and until that happens twice, the step Return to E122.

In addition, for potential control during warming up (step E147 affirmative), the number m of potential series control is 10 (step E151 affirmative), potential i control error processing is executed (step E153), and the number of times m is 10 (step E151 affirmative). is step E
Return to 122.

Also, if Status 1 is not in two-color mode (Stella
(step E148 negative), the process returns to step E122, but if status 1 is two-color mode (step E148 affirmative)
, the potential control vs. the first charge! 201 and second charger 20
4, if the first charger 201 performs potential control five times (step 1501'r fixed), the potential control will be set, and if it is the second charger 204, the potential will be controlled. When this is done twice (schedule 154M), potential control ends.

As described above, in one embodiment of the present invention, as explained in particular with reference to FIG. t'yD') signals (IVCLKl, IVCLK2) are output, and based on this video clock signal, video data number (■VDAT1.I Vl) Ar1) is sent from the host system 500 to the interface circuit 519 of the two-color LBP 199. Therefore, there is no deviation in the timing at which the transmission of video data signals from the host system 500 ends. Therefore, 2
It is possible to accurately determine the Δ-inclusive end position of paper for color L8P199.

[Effects of the Invention j As described above, the image forming apparatus to which the present invention is applied outputs a video clock signal synchronized with the end position of writing on paper from the printing side, and outputs a video clock signal 1. Since the system configuration is such that a video data signal is sent from the host 1 to the printing side based on the printing process, the end position IF of paper soaking on the printing side is accurate.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an outline of an embodiment of an image forming apparatus to which the present invention is applied, and FIG.
A block diagram showing the system configuration of LBP, Figure 3 is RO
A diagram showing the contents of the M data table, FIG. 4 is a diagram showing details of the interface signal between the interface circuit and the post system, FIG. Details of the commands used in color LBP.
Figure 8 is a block diagram showing details of the laser+f modulation circuit and semiconductor laser. Figure 9 is a circuit diagram showing details of the beam detection circuit and beam detection product. Figure 10 shows the relationship between the scanning range of the laser beam in one scan, the beam detection position, and the f-lighting position, and Figure 11 (shows the positional relationship of the data writing position on the entire paper). 12 is a circuit diagram showing the details of the print data 1M write control circuit, and FIG. 13 is a timing chart of the print data write control signal in the two-color print mode.
Figure 4 is a timing chart of the data writing ailJIII signal for one line, Figures 15 to 19 are flowcharts showing the overall operation of the two-color LBP, and Figures 20 and 21 are the page top counter and page end counter. counter, left margin counter, right margin counter and 2
A flowchart showing the subroutine for setting the beam scanning length correction value, Fig. 22 shows the potential υ1 during warm-up.
23 and 24 are flowcharts showing the subroutine for controlling the charging potentials i and lJ, and FIG. 25 is a flowchart showing the subroutine for controlling the potential before printing, and FIG. 25 shows a conventional image forming apparatus. FIG. 199...Two colors L B F) 500...Host system 519...Interface circuit

Claims (1)

[Claims] It consists of a printing side and a host side that sends various data signals to the printing side.The printing side outputs a video clock signal that stops outputting at the end position of paper writing, and based on this video clock signal, An image forming apparatus characterized in that transmission of a video data signal from the host side to the printing side is stopped.