JPH02544A - Device for formation of image - Google Patents

Abstract

PURPOSE:To eliminate the irregularity of the recording position of a sheet by feeding a video data signal from a host side to a printing side on the basis of a horizontal synchronizing signal output from the printing side and a video clock signal output from the printing side after a predetermined period of time is elapsed from the synchronizing signal. CONSTITUTION:A host system 500 feeds video data signals IVDAT1, IVDAT2 of dot image data to an interface circuit 519 on the bias of its horizontal synchronizing signal and video clock signal, etc. Thus, even if the system 500 does not calculate to output the data signal, a video data signal is synchronized with the clock signal from a 2-color LBP 199 after a predetermined period of time is elapsed from the output of the synchronizing signal from the LBP 199, and fed from the system 50 to the printing side. Accordingly, the LBP 199 eliminates a delaying factor for an electrostatic latent image forming operation with a laser beam, thereby suppressing the irregularity of the recording position of a sheet.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Field of Application) The present invention is applicable to a printing method such as a laser printer that includes a step of scanning a laser beam to form a static N 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 4 to the printer 2, the system status can be checked based on the system status. This command is sent to control the printer 2. Further, when controlling the printer 2, the printer 2 outputs a horizontal synchronization signal to the controller 4, and the controller 4 outputs a video data signal to the printer 2 based on the horizontal synchronization signal.
It is designed to be sent to.

However, when sending the video data signal from the controller 4 of the host side 3 to the printing side 1, the video data signal was sent based on the horizontal synchronization signal output from the printing side 1. There was a problem in that there was a high rate of variation in the recording position.

(Problems to be Solved by the Invention) In other words, in the case of the conventional image forming apparatus 2, the video data signal is sent from the host side to the printing side based only on the horizontal synchronization signal output from the printing side. For example, in a laser printer, when a laser beam is scanned by a printer unit to form an electrostatic latent image on a photoreceptor, printing from the host side is affected by the time required for a tan processing on the host side. There may also be a delay in the timing of sending the video data signal to the side. As a result, conventionally, there has been a problem in that the rate of variation in recording positions on paper increases.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an image forming apparatus in which variations in recording positions on paper are eliminated.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention is composed of an printing side and a host side that sends each insertion data signal to the printing side. A video data signal is sent from the host side to the printing side based on a horizontal synchronization signal outputted from the printing side and a video clock signal outputted from the printing side after a predetermined period of time has elapsed since the horizontal synchronization signal. shall be.

The video data signal is transmitted from the video data signal.

(Function) With this configuration, when sending a video data signal from the host side to the printing side, the host side does not have to perform arithmetic processing to send the video data signal, and the video data signal is output from the printing side. After a certain period of time has elapsed since the horizontal synchronization signal, a video data signal is sent from the host side to the printing side in synchronization with the video clock signal from the printing side. Therefore,
For example, in a laser printer, on the printing side, error factors in the operation of forming an electrostatic latent image using a laser beam are eliminated, and variations in recording positions on paper are eliminated.

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

The image forming apparatus of this embodiment has two colors L constituting the printing side.
The BP 199 and a host system 500 (external devices such as electronic meters, word processors, etc.) are coupled via a transmission controller (interface circuit, etc.), not shown. Then, the two-color LBP 199 receives 2fl type dot image data from the host system 500, modulates each of the two laser beams, executes the dot image data onto the photoreceptor (@carrier), and performs n-type dot image data. The two types of dot image data generated are independently developed and transferred onto recording paper.

That is, this two-color laser beam printer (1aserB
In the eag+ printer (hereinafter referred to as two-color LBP) 199, a first charger 2 is provided around the photoreceptor 200 as shown sequentially along the rotation direction indicated by the arrow.
01. Table 1 Matrix position sensor 202. First developer 203.
2nd band W device 204. Table 2 100 Lightning Level Sensor 205. Second present f! a device 206. Pre-transfer charger 207, transfer belt N H2
08, a peeling zone f2 device 2o9° cleaner 21OF3 and a static eliminator 211 are arranged, and a first looser beam 309 is irradiated onto the photoreceptor 200 between the first surface myoelectric potential sensor 202 and the first developer 203. and the first exposure is performed.
Further, a second laser beam 310 is irradiated between the second surface potential sensor 205 and the second phenomenon detector 2.degree.6 to perform a second exposure.

In addition, the IIJ control part of the two-color LBP in this example is the second one.
The block configuration is as shown in the figure.

The control unit of this two-color LBP uses a CPLI501 as the υj control center, and a ROM500 in which a system program is stored.
2, a ROM 503 in which a data table is stored, a RAM 504 used as a working memory, a timer 505, an I10 data input/output device 506, a print data 1211 circuit 513, and an interface circuit 519. We are fully prepared.

The contents of the data table stored in the ROM 503 are as shown in FIG.
contains first color top margin control data and address (4
002) and (4003) contain second color top margin control data, and addresses (4004) and (4005) contain left margin control data.

7) 'Lz (4006) (4007) has paper size A.
Bottom margin control data and address (4
008) and (4009) respectively contain write margin control data for the same paper size. Below, tables corresponding to various paper sizes are similarly included up to the address (4083).

From address (4090), data for top margin coarse adjustment, from address (40BO), data for top margin fine adjustment, from address (40DO), data for left margin coarse adjustment, from address (4100), 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 includes addresses (600F>) and is used as set data for controlling the developing bias of the process control circuit 522, which will be described later.

Address (6100) (6101) has 1st band 7I11
Contains target surface potential table data for position control.
The standard value is 5°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 (610G)
(610D) contains control output lower limit table data, and the surface potential limit table data, the control output upper limit table data, and the υItll 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 for a temperature range of 10°C to 40'C, which is 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. It performs input/output of a process control circuit 522 that controls the output of a high-voltage power supply 523 and the like in response to input signals.

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 modulation circuit 521 that performs optical modulation of the semiconductor laser 303 is driven and controlled to write 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 518 using a high-speed response PIN diode detects one of the two light beams being scanned by the laser scan motor, and the beam detection circuit 517 detects one of the two light beams being scanned by the laser scan motor. The analog signal from 518 is digitized by a high-speed comparator to create a horizontal synchronization pulse, and this is used to write print data.
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 unit 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 3 bits
Whether the bidirectional data bus, ID5TAG, is used as a status data bus to the host system 500 using the data bus selection signal, the host system 500
Select whether to use it as a command data bus. 15TB is a strobe signal for latching the above command data in the interface circuit, 188Y
is a signal for permitting transmission of the frJ strobe signal l5T8 and for permitting reading of status data.

I1-ISYN1 is a horizontal synchronizing signal for the first color and requests transmission of one line of print data.

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

IPEND1 is the page end signal of the first color and notifies the end of the line.

The host system 500 is the IH3YN1.1VCL.
Based on KI, the video data signal IVDATI of the first color dot image data is sent out, and when IPEND1 is received, the sending is stopped.

Similarly, IH8YN2 is the second color horizontal synchronization signal, IV
CLK2 is the second color video clock signal, IPEND
2 is the page end signal of the second color, and the host system 5
00 is the video data signal [V
Sends DAT2, and stops sending when IPEND2 is received. This video data signal IVDATI, IVDAT
2 is sent to the control circuit including print data 1. The above relationship is shown in FIG.

IPRDY is a signal that informs that the two-color LBP 199 is in a ready state, IPREQ is a signal that allows the host system 500 to send a print start signal IPRNT,
IPRME is a prime signal that sets the two-color LBPI 99 in an initial state, and IPOW is a signal that informs that the two-color LBP 199 is energized.

Next, details of commands and statuses used in the two-color LBPI 99 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.
J is the cassette upper stage paper feed designation command, C3TL is also the lower stage designation command, VSYNG is the host system 50
Command that specifies the start of sending print data from 0, SP
l, SF3. DPl is a command that specifies the print mode, SPl is a mode that specifies printing operation for only the first color, SF3 is a printing operation for only second color, and DPI is a mode that specifies printing operation for both the first color and second color. . MF1 to MF9 indicate manual feed mode designation commands, respectively.

In FIG. 7, during paper transport, paper is being fed 2
Status indicating that paper is being transported in color 18P199, VSYNC request is status indicating that 2-color LBP 199 has received a command to start printing and is ready to receive print data, and manual feed is in manual feed mode. The status indicates that the upper/lower cassette is in the selected cassette in the cassette paper feeding mode, and the print mode is 1st color, 2nd color, 2nd color.
The color is the status indicating the selected print mode,
Cassette size (upper row) and cassette size (lower row) are the statuses that indicate the size code of the cassette installed in the device, and toner color (first color) and toner color (second color) are the toner colors of the developer device installed in the device. The status indicates the code, Test/Maintenance indicates the test/maintenance state, Data resend request indicates the need to reprint due to a jam, etc. During wait, the 2-color LAP is in the fuser warm-up state The operator call status indicates that the 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. Paper Out indicates that there is no paper in the specified cassette, Paper Jam indicates that paper has jammed inside the machine. No toner of the first color indicates that there is no toner in the first developing device, and no toner of the second color indicates that there is no toner in the second developing device.
A second laser failure indicates that the second laser diode does not reach the specified output or the beam detector cannot detect the beam.A second laser failure indicates that the second laser diode does not reach the specified output. Indicates that it is not reached. Scan motor failure indicates that the scan motor does not reach the specified number of rotations even after a certain period of time has passed, or that the rotation speed has deviated from the specified rotation speed for some reason after the specified rotation speed.
Potential sensor failure and second potential sensor failure each indicate that the surface potential of the photoconductor 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. 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 a losser diode enable signal LDO.
NIO is input, and when this signal becomes LOW level, the transistor 810a becomes ONL,...
A bias current flows through the first loser diode 812a.

807a and 808a are high-speed analog switches for modulating the losser diode 812a, and when a HIGH level voltage is applied to the gate (G) of each analog switch, the connection between the drain (D) and the source (S) becomes high. The resistance becomes low and turns ON. When a LOW level voltage is applied to the gate (G), the resistance becomes high and turns off. R21a is an analog switch 807a, 808
Short circuit protection resistance when a changes from 0N to OFF, 813a, 8
14a is a gate driver for the analog switch 807a, aoaa. C02a 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 IVE-OR
gate, which changes depending on the output of the 2AND gate 820a. The 2AND gate 820a outputs a LOW level when either of the two gate inputs becomes a LOW level, and the EXCLUSIVE-OR gate 815 outputs a LOW level.
The output of a becomes LOW level, the analog switch 807a is turned on, and the loop diode 812a is turned on.
It becomes N 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 the first sample signal SAMP10 is L
This is when the level is OW. When both inputs of the 2AND gate are at HIGH level, the EXCLUS IV
The output of the E-OR'7'' route 816a becomes LOW level, the analog switch 808a is turned on, and the M route is turned on.
The diode 812a is turned off.

806a is an operational amplifier and constitutes a voltage follower circuit. 001 is a Zener diode
The output of the diode 812a is regulated to be within the maximum rating. Further, the resistors R19a and C01a constitute an integrating circuit, and R20a' is a discharge resistor that charges the capacitor C01a by 111 charges at a constant value of υ1. 804a is an analog switch whose gate (G) is connected to inverter 805a;
The first sample signal SAMP10 is input to this input. 803a is a transistor for level conversion, R22a is a base current limiting resistor of transistor 803a, and R18a
802a is a comparator which has a hysteresis characteristic due to the action of resistors R14a and R15a.

The paper 11j' is on the input side of the comparator 802a.
The output voltage of the first router monitor amplifier 801a is applied through the CR 14a. A photodiode 801a detects the optical output from the first loser diode 812a.
This is an amplifier for the output of 11a. Resistors R12a, R13
a, VRO1a is a resistor that regulates the amplifier of the operational amplifier 5oia. Therefore, by changing VROla, the amplifier of operational amplifier 801a can be changed. R11a is a load resistance for the output of the photodiode in the first loser diode, and this resistance R11a
A voltage proportional to the output current of the photodiode 811a is obtained across both ends of the photodiode 811a. 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 5oia is applied to the - inputs. Further, a voltage divided by resistors R16a and R17a is applied to the + 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.
IG) - level changes to LOW level, and the 1st Loser day signal @LRDY10 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 ten input terminals of the voltage follower 819 have exposure: II! A voltage divided by a 1 volume 821 and a resistor R31 is input, and by varying the exposure adjustment volume 821, the output voltage of the voltage follower 819 is also changed.

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 LDON1 ([10W level is reached, a bias current flows through the first loser diode 812a.
When the sample signal SAMP10 becomes LOW level, the analog switches 804a and 807a 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 not ONL. Therefore, the first rule
A current flows through the diode 812a to such an extent that it does not emit light. At this time, since no current flows through the first photodiode 811a, the output of the comparator 802a is L.
Since the voltage becomes OW level and the transistor 803a is turned off, the capacitor C01a is charged through the resistors R18a and R19a. The time constants of the resistors R18a, R19a and capacitor C01a during this charging are selected to be approximately 20 to 50+n5ec.

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.

The transistor 81 is connected to the first loser diode 812a.
A summation current of the bias current from 0a and the collector current from the transistor 809a flows, and when the summation current exceeds the threshold current of the first loser diode 812a, the second loser diode 812a emits light. When the first loser diode 812a emits light, a current flows through the first photodiode 811a for monitoring, 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. Ru. operational amplifier 80
When the output voltage of 1A exceeds the voltage divided by the resistors R16a and R17a, the output of the comparator 818a, that is, the first router signal @LRDY10 changes from HIGH to LOW.
It becomes OW level. When the output voltage of the operational amplifier 801A exceeds the one input terminal voltage of the comparator 802a, that is, the first router light amount setting voltage, the comparator 802a
The output of 02a changes from LOW to HIGH level, transistor 803a turns on, and capacitor C01a is discharged through resistor R19a. Therefore,
The base voltage of the modulation transistor 809a also decreases, and the optical output of the first loser diode decreases. When the optical output of the first loser diode decreases, the voltage at the manual input terminal of the comparator 802a also becomes lower than the set voltage of the second loser diode, and the transistor 803a is turned off again, and the capacitor C0 is turned off again.
1a is a resistor R18a.

It is charged up through R19a. In this way, when the optical output of the first loser diode 812a reaches the previous set voltage of the first loser light, the comparator 802a gradually repeats ON-OFF at around the first set voltage of the first loser light. The optical output of the first loser diode 812a is stabilized 1
When the CPU 501 confirms that the first loser ready signal LRDYIO has become a 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 SA for each line outside the print area.
The MP10 is set to LOW level for a certain period of time, and the analog switch 804a is turned on.

807a is turned on to stabilize the laser tip.

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 VDAT10 is sent out from the host system 500.
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 optical ffil constant voltage of the laser diode 812b, that is, to the bk- input terminal of the comparator 802. Therefore, by varying the exposure adjustment volume 821, the output voltage of the voltage follower 819 also changes, so the voltage at one input terminal of the comparators 802a and 802b changes simultaneously. Therefore, the optical output of the first laser diode 812a and the optical output of the second laser diode 812b can be adjusted simultaneously by making the exposure volume 821 variable.

FIG. 9 is a detailed circuit diagram of the beam detection circuit 517 and beam detector 518 in FIG. 2. In Figure 9, 5
18 is a beam detector that uses a PIN diode with very fast response.

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. Further, R46 is a positive feedback resistor for providing hysteresis characteristics, and 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 positive input terminal voltage of the comparator 825, and the comparator 825 outputs a negative pulse H3YO.

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 from the beam starting point 900 at time O by the next surface of the polygon mirror. Begin the beam. 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 80.

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 of paper size 86.

dl is the distance from the beam detection point 902 to the writing start 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. d and d indicate the effective printing range in 80 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 represents A6 paper and 918 represents A3 paper. 904,905,906゜907.908
, 909 show the same positions 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. Reference numeral 915 represents the trailing edge of the ○ size paper, and 914 represents the data writing end point of the ○ 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 write 11111
The main function of one circuit 513 is that the host system 500
The print data is sent to the laser modulation circuits 514 and 521 in order to be written in a predetermined area on the photoreceptor 200 according to the size of the paper to be printed. It also sends out signals necessary to the laser light output stabilization circuits of the laser modulation circuits 514 and 521. It also sends timing signals necessary for sending print data to the host system 500.

In FIG. 12, 830 is the laser modulation circuit 514, 5
21 and UEI]? -j'-') 11 included 11 Jt 11 times This is an input/output port for sending and receiving signals necessary for ilJ control within 1513. The counter 831 is composed of a counter 1 timer that performs write I control of print data and V control such as laser light output sampling, and the setting of the operation mode and the preset value of the counter 1 timer can be programmably performed by the CPU 501. It is something.

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 inputted to the beam detection signal H8YD, which is the output of the beam detector circuit 517.
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 beam detection signal H8YO is input to the gate input G6. A 1500 KHz clock is input to the clock input CK6 of the timer 865. Output SMP of the timer 865
TD is input to one of the 2OR gates 877, and the 2O
The output of the R gate 877 is the first sample signal SAMP10.
．． As the second sample signal SAMP20, the respective rules are
The modulation circuit 514. 2NA in the second laser modulation circuit 517
It is sent via ND gates 886 and 887. Said 2N
The other input of AND gate 886 is T10 boat 830.
output second laser diode enable signal L[)ON
ll 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 first and second sample signals SAMP20 can be inhibited independently. Similarly, the second laser diode enable signal LDON21 output from the T10 boat 830 is input to the other input of the 2NAND gate 887, so that the second sample signal SAMP20 can be independently inhibited. Also, 2OR gate 877
The output laser test signal LDTSI of the T10 boat 830 is inputted to the other input of the , and by setting the laser test signal LDTS1 to )(rGH level), the first semiconductor laser 302 and the second semiconductor laser 303 are forced to emit light. The T10 boat 830 is inputted with the laser ready signal LRDY10 and the second laser ready signal @LRDY20, and by determining the first and second laser ready signals in the forced emission state of each laser. , you can 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 H8YO 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 and is input to the T10 boat 830. The aforementioned F/Fs 866 and 887 are also reset by the output of the 2OR gate 869. The input of the 2OR gate 869 is the first . The second 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 MH2) corresponding to the minimum modulation unit of the laser beam, 1 dot.

837.838 is the same J-KF/ as 834.835 above.
F constitutes a quaternary counter, but J-KF/F83
7, an n-bit binary counter 84 is input to J-.
5 carryout output CO is input via an inverter 846.

J-KF/F834, 835, 837.838 performs a toggle operation in synchronization with the CK input when the input to J- is HIGH, and the input to J- is LOW.
When it reaches the W level, its Q output interrupts the toggle operation. As a result, when the pulse interval during normal operation is set to "1", the Q output second video crawl signal VCKY21 of the J-KF/F838 in the subsequent stage is r
It becomes 5/4J, which means that it has been extended by 1/4 clock. The preset input Do-Dn of the n-bit binary counter 845 is connected to the main power Q of the n-bit latch 847.
O~Qn are connected, and the setting value is set by CPU501.
It is possible to set a value according to Dip-sw etc. with . The above setting value is for setting the carry-out number of the n-bit binary counter 845 between one line (while LSTl is at HIGH level), and as a result, r
This is used to set the number of 5/4J clocks to be generated. Inverter 839. The shift register 840°2NOR gates 841 and 842 are connected to the n-bit binary counter 845.
This is a circuit that provides a predetermined operation.

The second video clock signal VCKY21 is a scanning signal of two laser beams 1. It is used to correct the difference between the two. In this case, the first video clock signal VCKX 21 may be specified for the laser beam of officer 1 having a long scanning length, and the second video clock signal VCKY21 may be specified for the laser beam of fL2 having a short scanning length. Reference numeral 848 denotes a selector for specifying the selection based on the output CHGCK of the I10 port 830.

Next, a correction method will be explained using an example. For example, if laser beam 1 with a long scanning length is 200 am and laser beam 2 with a short scanning length is 19911 am, the difference in scanning length is 1
It becomes 11. 2400 if the resolution is 12 lines/1m
It is sufficient to stretch the video clock signal VCKY21 of the laser beam with a short scanning length by 12 dot clocks per dot clock (200x12>.Here, in one correction, the video clock signal VCKY21 is stretched by 1/4 dot clock, so 2400
Between dot clocks, the correction for 1/4 dot clock is 1.
Performed 2x4-48 times.

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 IMH2) obtained by dividing 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 laser beam can be corrected at the same time. The correction of the error is D
Adjustment can be made in units of 8 dot clocks by changing the settings of both counters depending on the IP-8W, etc. The reason for setting it in units of 8 tod 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 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 whose one input is the output LMCTO of the left margin counter 863.

The other input is the output RMCTO of the line 1-margin counter 864 via an inverter 874, so the output of the 2AND gate 875 represents the horizontal printing area.

The output of the 2AND gate 875 is sent to the shift register 86.
8, the signal is shifted by four dot clocks, and the horizontal print area signal HPEN1 is output from the Q output.

The horizontal print area signal HPENI is input to the GE large input of the n-bit bino-recounter 850 and to the shift register 854. the n-bit binary counter 850;
2NAND gate 849. n-bit latch 851. J-
KF/F852 has a circuit configuration that can shift the data write start point to the right in units of one dot, and J-KF/F85
The output of No. 2 outputs the first horizontal printing m-area signal HPENBI. Preset inputs DO to Dn of the n-bit binary counter 850 marked with # are used to set the shift number for right shift, and are connected to the output of the n-bit latch 851, and the set value is set by the CPU 501 according to Diρ-SW, etc. can be set. The shift register 854 and the shift register 855. The inverter 853 is connected to the horizontal printing area signal HP.
The circuit is configured to shift ENI to the right by two dot clocks, and the output of the shift register 855 is the second horizontal print area signal HPENA1. 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 the AND gate 857 is a first video clock signal VC indicating the video clock signal for the first horizontal printing area decrement.
LKB1, one of the inputs of the AND gate 857 is the first horizontal print area signal HPENB1. The other is the Y1 output of the selector 848. Also, the output of the AND gate 856 is a second
video clock signal VCLKA1F, AND gate 8
One of the inputs of 56 is the second horizontal printing area signal HPEN.
AI, and the other is the Y2 output of the selector 848.

As described above, the first horizontal print area signal HPENB1. The first video clock signal VCLKB1 is used to correct errors in the scanning start points of the two laser beams. In this case, the second horizontal printing area signal HPENA1. Second video clock signal V
It is sufficient to specify CLKA1, specify the first horizontal printing area signal ()-IPENBI, and first video clock signal VCLKB1 to the laser beam of Sl having a slow scanning start point, and adjust the error d.

The selector 858 is a selector that performs the designation, and is performed by the output CHGI 2 of the 110 port 830.

859 to 862 are counters for setting the data writing start point and data writing end point in the vertical direction (paper traveling direction), and 859 is a counter for setting the data writing start point for the first color.
A page top counter 860 is a first page end counter that sets the data writing end point for the first color.861 is a second page top counter that sets the data writing start point for the second color.862 is the data for the second color. This is a second page end counter that sets the write end point.

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 of each counter 859 to 862 = cK
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 PTCTIO of the first page top counter 859; the other input is the output PECTl 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 2AND 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 are inputted to the I10 port 830.
Color page end signal IPEND20 to host system 5
Send to 00.

878 is the first color horizontal synchronization signal IH8YNIO,
79 is a ZNAND gate that sends the second color horizontal synchronization signal TH8YN20 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 IVDT10 from the host system 500 to the first loser modulation circuit 514 as the first video data signal VDAT10.
It is an ND gate.

885 is the second color video data signal IVDT20 from the host system 500, and the second laser modulation circuit 521
3 to be sent as a second video data signal VDAT20 to
It is a NAND gate.

888 is an inverter that sends the first loser diode enable signal LDON10 to the first loser modulation circuit 514;
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 section that operates in response to a control command issued from the control section of the two-color LBP 199 will be described in detail according to the flowcharts shown in factors 15 to 24.

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

FIG. 15 shows the self-diagnosis and warming-up processes of the two-color L8P199.

In FIG. 15, the operator turns on the power supply 520.
Then, the system program 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 A112). Note that if you are in test print mode (
Step 107 (Yes), test print processing is executed (Step A109), and if the maintenance mode is maintained, maintenance processing is executed (Step All0).

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 does not become ready even after 30 seconds have elapsed since it was turned on (step A113 negative, A115 affirmative), trouble 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 remover II 2
Each of the 11 lamps is turned on (step 118), and through delay processing (step 119), the first laser diode 302, the second laser diode 303, the laser test,
Each of the pre-transfer chargers 208 is turned on (step A120).

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).
Yes), each beam detection ready is checked using the horizontal synchronization signal H8YNC (step A128). Note that if the first laser diode 302 is out of order (step 122 negative), the second laser failure process (step A124> is executed), and if the second laser diode 303 is out of order (step 123 negative), Second laser failure processing (step A
l25) is executed. In addition, horizontal synchronization signal H8YN
If the beam is not detected at C (No in step 126),
Beam detection failure processing (step A127) is executed.

After the subsequent delay processing (step AI 29), the stripping charger 2
09 is turned on (step A130), and after a delay process (step A131), the warming-up potential υJtil as shown in FIG. 70 is executed (step A132). Note that step A132 is a process to enable printing as quickly as possible during the first printing.

After the subsequent delay processing (step A133), 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 developer 203, the clutch of the second developer 206, the first charger 201 .
Second belt? Each of the W units 204 is turned off. Step A
138, the drum motor of the photoreceptor 200, the snow remover 21;
1. Loser diode 302. Second laser diode 303. Each of the motors of the fixing device 222 is turned off.

In step A140, the blade solenoid is turned off.

Thereafter, when the fixing device 221 becomes ready (step 141 is affirmative), the self-diagnosis and warming-up processes in steps A101 to A141 are completed, and the 16th
Proceed to the routine shown in the figure.

FIG. 16 shows a two-color LBP1 for the host system 500.
99 and issues a print request when the status of each part is determined to be normal from the host system 500.

In FIG. 16, first, a determination is obtained from the host system regarding the contents of status 5 (steps A142 to △1).
45). That is, in step A142, it is determined whether or not to replace the toner pack. If you need to replace it (
(Yes in step A142), wait for the toner bag to be replaced (step A146), and complete the replacement (step A1).
46 (Yes, A147), the process proceeds to step A143. In step A143, it is determined whether the empty switch of the first developing device 203 is set to 0N10FF to determine whether or not there is no toner of the first color. If there is no first color toner (step A1
43 (Yes), check whether it is the second color mode based on status 1 (Step A148), if it is the first color mode and two-color printing mode (Step A148, No),
When the supply of the first color toner to the first developing device 203 is completed (step A149 is affirmative), the process proceeds to step A144 at A150. If it is the second color mode (step A148 affirmative), step A149. Skip step A150A
Proceed to 144. In step A144, the second yA imager 2
0N10FF of the empty switch 06 determines whether or not there is no second color toner. If there is no second color toner (step A144 affirmative), check whether the mode is the first color mode based on status 1 (step A151).
, if the mode is the second color mode and the two-color printing mode (step A151 negative), the second color toner supply to the second developing device 206 is completed (step A152 affirmative, A153), and the process proceeds to step 145. Furthermore, if it is the first color mode (step A151 affirmative), steps A152 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 that specifies the first color mode (step A154 is affirmative), the first color mode is set to status 1 (step A157), and if there is a command that specifies the second color mode (step A155 is affirmative). ),
The second color mode is set for status 1 (step A158).

Further, if there is a command specifying the two-color printing mode (step A156 affirmative), 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 it remains OFF ( Step A161 (No), the process returns to Step Δ142, and if it is turned on (Step A161 Yes), the print request is turned off (Step A162), 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 checked based on status 1 whether the mode is the second color mode. 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 A177i4 constant), step A178
is skipped and proceeds to step △179.

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 A1
80), proceed to step A181. If it is the second color mode, step A180 is skipped and the process proceeds to step A181.

In step A181, 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 υ 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 turned on.

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

If it is the second color mode (step A187ti fixed), step A188 is skipped and the process proceeds to step A190, and as shown in FIG.
Ill will be performed (step A189).

In step A191 following the delay processing in step 190, it is checked based on status 1 whether the mode is the first color mode. If the first color is not [- (step A191 negative), the developing bias 409 of the second developing device 206 is set to 0NL (
Step A192), then proceed to step A194. If it is the first color mode (step A191 portrait), step A
192 and proceeds to step A194,
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). ), the process proceeds to step A199, and the paper feed motor is turned off after the delay process in step A208 (step A209). If it is determined that the paper is in the lower stage, step A195 is skipped, and the paper feed motor is reversed to perform lower paper feeding (step A197) in the delay process (step A196).
), proceed to step A199, and proceed to step A208
After the delay processing, the paper feed motor is turned off (step A).
209).

In step 199, it is checked based on the status 1 whether or not the mode is the second color mode. 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 synchronization signal H3YNC, 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 page top 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 VSYNC command is held (
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 the image @ writing starts, and then,
Based on status 1, it is confirmed whether the mode is two-color printing mode (step A211). Then, if it is the first color mode and the second color mode (step A211 negative),
The process proceeds to step A213, and if it is the two-color mode (step A211 affirmative), the process proceeds to step A213, and at the same time, the first charging potential control as shown in FIG. 70 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 processing in step A214, and if it is the second color mode (
(Yes in step 213), the process proceeds to step 216 after the delay processing in step A215.

In step 216, when the registration motor is turned on and the total counter is turned on, the total counter is turned off after delay processing (A217) and the process proceeds to step A221, and at the same time, after execution of a delay corresponding to 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 positive), the first color image writing is completed and I
PENDI 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
4 (affirmative), when there is first color toner in the first developing device 203 (step A231 negative), second development! 2nd on 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, if there is no toner of the first color in the first developing device 203 ((Yes in Step A231) and there is no toner of the second color in the second developing device 206 (Yes in Step A232), the printer is ready for printing as shown in FIG. IPRDY is turned off (
Step A252).

Further, even if there is no first color toner in the first developing device 203 (step A231 affirmative), there is second color toner in the second developing device 206 (step A232 negative), and both the first color and the second color are present. If both are the same color (step A233 affirmative), when the second color printing mode designation command is issued (step A234 portrait), the developing bias 409 of the first developing unit 203 and its clutch are turned off ( Step A235), the charging potential control of the first charger 201 is stopped, and the first charger 201 is turned off (Step A235).
236), the second color mode of status 1 is set (step A237>, and the print request IPREQ is O
N (step A248).

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
(Yes), the developing bias 409 of the first developing device 203 and its clutch are turned off (step A235), and the charging potential control of the first charging device 201 is stopped.
1 is turned off (step A236), the second color mode setting of status 1 is executed (step A237),
Print request ■PREQ 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 affirmative), 2nd color image writing is completed 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, affirmative), even if there is no second color toner in the second developing device 206 (step A240, affirmative), there is first color toner in the first developing device 203 (step A241, negative); If all the colors are the same (step A242
(affirmative), when a command specifying the first color printing mode is issued (affirmative in step A243), the developing bias 409 of the second developing device 206 and its clutch are turned off (step 244), and the charging of the second charger 204 is turned off. The potential 'IA' is stopped, the second charger 204 is turned off (step A245a), the first color mode of status 1 is set (step A245b), and the print request IPREQ is sent as shown in FIG. is turned on (step A248).

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 A229 it is determined based on the status 5 whether or not the second color toner is out. And step A228
．． If there is no toner at A229, the print ready IPRDY is turned off as shown in FIG. 67 (step A252>).

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 1 as shown in FIG. 22! I! position υ11
11 twice (step A230). In addition, in the routine of steps A221 to A24B, step A
By deleting the judgments in steps 232 and 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 devices. In the figure, after the process of turning on the print request IPREQ in step A248, IPRN'r
Judgment process of waiting for ON for 5 seconds (steps A249, A25
0) is executed and IPRNT turns ON (step A249 is affirmative), the print request IPREQ turns OFF.
F (step A251), and it is determined whether the print mode has been changed (step A266>).

If the print mode is changed, skip step A266.
Yes), return to step A177, and step A177~
Between steps A194 and 1 while checking status 1.
The developing device 203 or the second developing device 206 is made ready for development.

If the print mode has not been changed (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 (Yes in step A250), after the stop processing in steps A253 to A265, the process returns to step A142 and enters a standby state waiting for a command from the host system 500.

If the print ready is IPRDYIfiOFF (step A252), no printing operation is required, so after the stop processing in steps A253 to A265, the process returns to step A142 and enters a standby state waiting for a command from the host system 500.

20 and 21 show step A204 in FIG. 17.
3 is a flowchart showing the processing of FIG.

In the subroutines shown in FIGS. 20 and 21,
A process for coarsely adjusting and setting the top margin from step 8101 to step B107, a process for finely adjusting and setting the top margin from step 8114 to step B119, a process for finely adjusting and setting the bottom margin from step 8120 to step B123, and step 8124 ~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 setting the top margin coarse adjustment in steps 8101 to 107, the first color top margin table data DID is taken (step B101), and the top margin coarse adjustment switch is read (step B10).
2) Also, read the top margin rough 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 B
106), the process advances to steps 8108 to B113, a routine for coarsely adjusting and setting the bottom margin. Moreover, if status 1 is two-color mode (step B105 affirmative),
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 designated paper size in step 8108, in the following step B109, the first color top margin table data D1 is added to the bottom margin table 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. Also, if step 1 is the second color mode (step 8111iJ fixed)
, set the calculation result D6 in the second page end counter 862 (step Bl 12), and similarly step 8.
The routine advances to steps 114-B19.

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.

If the status 1 is not the two-color mode in the following step 8118 (No in step 8118), step B12O-
Proceed to the bottom margin fine adjustment set routine of Bl 23. Further, if the status 1 is the two-color mode (step B118 affirmative), the calculation result D9 is set in the second page top counter 861 (step B119), and the routine similarly proceeds to steps 8120 to B123.

In step B120, 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 coarse adjustment table D8 is added to or subtracted from the value of the calculation result D10 to obtain the calculation result D11.

If the status 1 is not the two-color mode in the subsequent step B122 (step B122 negative), steps B124~
The process advances to the left margin coarse adjustment set routine of 8128. Further, if the status 1 is the two-color mode (step 81221 fixed), the calculation result D11 is set in the second page end counter (step 8123), and the routine similarly proceeds to steps 8124 to 8128.

In step B124, left margin table data D1
2 is read, the left margin coarse adjustment switch is read in the subsequent step B125, and the left margin coarse adjustment table data D13 corresponding to the switch is read in the subsequent step 8126.

In the following step B127, the margin rough adjustment table D13 is added or subtracted from the value of the left margin table data D12 to obtain the calculation result 014.

In the following step B128, the calculation result 014 is set in the left margin counter 863, and 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 B130, the rough margin adjustment table data 013 is added to or subtracted from the value of the light margin table data D, 15 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.

In step B132, the left margin fine II switch is read, and in the subsequent step B133, the left margin fine adjustment table data 017 corresponding to the switch is read, and in the subsequent step B134, the value of the table data D17 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 boat 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 D18 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, the I10 port 830 is set in the subsequent step B141, and the process in step A204 shown in FIG. 17 is completed.

FIG. 22 is a flowchart showing potential control during warm-up and potential control before first printing.

Potential control during warming up is performed using the first charging initial JI.
Read the value CHo T + of the 111it output from the table data (step Cl0I), and send the read value to the D/A.
It is set in the converter 576 (step C102).

Further, the value CHDT2 of the second charging initial υJIO output is read from the table data (Step C103), and the read value is set in the D/A converter 582 (Step C103).
104).

When the first charger 201 is turned on in the subsequent step ClO3, the first charging potential υ is increased as shown in FIGS. 23 and 24.
1 run is executed (step 0106). After the subsequent delay processing (step C107), when the second charger 204 is turned on in step 0108, the second charging potential υIII is applied as shown in FIGS. 23 and 24 (step C109).

And potential i, 1161! The number of potential control steps n is increased step C110), and when the potential control number n reaches 3, steps ClO3-Step C11l) are repeated.
When the rotation is performed, the first charger 201 and the second band m2s2
04 is turned off (step C112), and this potential control during warming-up is completed.

The potential control before the first print is performed when the status 1 is not the second color mode (step D101 negative).
The charger 201 is turned on (step 0102), and the seventh
As shown in FIG. 1 and FIG. 72, the first charging potential control is executed (step D103), and if only the first color mode is selected (affirmative in step D104), the potential control before first printing ends.

Also, 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 0107), and the potential υ1@ 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. As shown, the second charging potential υJlI
1 is executed (step D107), and the potential 1i111II before the first print ends.

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

Regarding the subroutines shown in 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). Then, either the first band NM level control or the second charging potential control is selected (step E103), and based on the data table in the ROM 503, in the case of the first charging potential control, steps 6104 to E109 are selected. Each process is executed,
In addition, in the case of second charging potential control, steps E113 to
Each process of step E118 is executed.

Then, in step E110 and step E119,
The first target surface potential data (VO81) and the second target surface potential data (VO82) are each corrected to correspond to the actual temperature of the photoreceptor 200, and corresponding correction data VO31- and VO32' are obtained.

In subsequent steps E111 and E120, the multi-values obtained in steps 6104 to E110 and
In order to store the multi-values obtained in steps E113 to E119 in a common register, arithmetic processing as shown in step E111 and step E120 is executed.

In the following steps E112 and E121, A/
The D converter 593 selects the first potential sensor 202 and the second potential sensor 205, respectively.

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

First, 1. A delay process is executed for a time corresponding to the travel distance between the second chargers 201 and 204 and the first and second surface muscle potential sensors 202 and 205, and the first. 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, a self-diagnosis is made as to whether or not the read value is greater than or equal to VOS+VouAX, according to the arithmetic expression: VS≧vos+voIJAX. If the result is above (step E124 affirmative), potential control error processing is executed. (Step E12
5). 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), check step by step how much it deviates from the target by, for example, 200V, 100V, 50V (steps E127 and E128).
．． E129>, processing is executed to set the control amount to the same size as ΔX1 or ΔX2), or twice, four times, and six times, respectively (steps E130.E131.E13).
2. 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.
At step 6, 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), 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, CHo T
After setting l=CHo T (step E139), CHDT+eD/A
The process of setting in the converter 576 is executed, and the process advances to step E145.

Also, if this determination result is M2 charger 204, Cl-
After setting 1o T 2 = CHD T (step E 141 ), CHD T
+ @The process of setting in the D/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 146 and subsequent steps in FIG. 24.

That is, if the potential is controlled before the first print (step 146 affirmative), the potential control number m is three times (step 150 affirmative), and the non-convergence due to potential control ends.
If this occurs up to twice, the process returns to step E122.

Also, if the potential during warming up is 2, 11 III (step E147 description), the potential control number layer is 1.
If it is 0 times (step 150 is affirmative), the potential υ1111 error process is executed (step E153), and if it is executed up to 9 times, the process returns to step E122.

Furthermore, if status 1 is not two-color mode (step E148 negative), the process returns to step E122, but if status 1 is two-color mode (step 148 affirmative),
The number of times of potential control is the first charger 201 and the second charger 204
In the case of the first charger 201, the potential υ control ends when the potential control is performed five times (step 150 is affirmative), and in the case of the second charger 204, the potential control ends twice. When this is done (step 154 affirmative), potential control ends.

As described above, in one embodiment of the present invention, as explained particularly with reference to FIGS. 4 and 10, two-color 18P199
interface circuit 519 to the host system 50
0 for each color, horizontal synchronization signal (IH8YN1.[H8Y
N2) requests transmission of one line of print data, and after a certain period of time has elapsed after the request for transmission of one line of print data, the video clock signal (IBCLKl, IVCLK2>
Requests the sending of print data. The host system 500 is configured to send video data signals ((IVDATI, IVDAT2) of dot image data to the interface circuit 519 based on the horizontal synchronization signal and video clock signal.

Therefore, the host system 500 can perform two-color LBP processing without performing arithmetic processing for sending video data signals.
After a certain period of time has elapsed since the horizontal synchronization signal is output from the two-color LBP 199, a video data signal is sent from the host system 500 to the mark 14 (ilIl) in synchronization with the video clock signal from the two-color LBP 199.
In step 199, there is no delay factor in the electrostatic latent image forming operation by the laser beam, and variations in the recording position on the paper can be suppressed.

[Effects of the Invention] As described above, the image forming apparatus to which the present invention is applied is capable of controlling the host computer based on the video clock signal from the printing side after a predetermined period of time has elapsed since the horizontal periodic signal was output from the print WA side. Since the system configuration is such that video data signals are sent from the side to the printing side, the cost of calculation processing time on the host side, which was a source of error in the electrostatic latent image forming operation using a laser beam in the conventional system configuration, is eliminated. can be done.

[Brief explanation of the drawing]

FIG. 1 is a block diagram schematically showing an embodiment of an image forming apparatus to which the present invention is applied, and FIG.
A block diagram showing the system configuration of color LBP, Figure 3 is R.
Figure 4 is a diagram showing the contents of the OM data table, Figure 4 is a diagram showing details of the interface signals between the interface circuit and the host system, Figure 5 is an explanatory diagram of the relationship between the interface signals and data writing positions, and Figure 6 is 2. Figure 7 is a detailed explanatory diagram of the commands used in color LBP, Figure 7 is a detailed diagram of each status used in two-color 1BP, Figure 8 is a block diagram showing details of the laser modulation circuit and semiconductor laser, Figure 9 10 is a circuit diagram showing details of the beam detection circuit and the beam detector, FIG. 10 is a diagram showing the relationship between the scanning range of the laser beam at one time and each position of the beam detection position and the data writing position. The figure shows the positional relationship of data writing positions on the entire paper, Figure 12 is a circuit diagram showing details of the print data write control circuit, and Figure 13 is a diagram of the print data omission 1iIJ @ signal in two-color printing mode. Timing chart, FIG. 14 is a timing chart of data write control signal for one line, FIGS. 15 to 19 are flowcharts showing the overall operation of the two-color LBP, FIGS. 20 and 21 are page top counters, A flowchart showing a subroutine for setting a page end counter, a left margin counter, a right margin counter, and a 2-beam scan length correction value; FIG. 22 is a flowchart showing a subroutine for potential control during warm-up and potential control before first printing; 23 and 24 are flowcharts showing a subroutine for band N potential control, and FIG. 25 is an explanatory diagram of a conventional image forming apparatus. 199...Two-color LBP 500...Host system 519...Interface circuit cost, cutting edge Yasuo Miyoshi■ Fig. 24 Co-Printing side 3 Host side Fig. 25

Claims (1)

[Claims] It consists of a printing side and a host side that sends various data signals to the printing side, and includes a horizontal synchronization signal output from the printing side and a video clock output from the printing side after a predetermined period of time has elapsed from this horizontal synchronization signal. Based on the signal
An image forming apparatus characterized in that a video data signal is sent from the host side to the printing side.