JPH1031372A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device which can be compositely utilized as a sensor part for controlling image forming timing or controlling the jamming of a recording medium by monitoring the power source fluctuated state of a transfer electrification part and detecting the fed recording medium at a position where a transfer means is arranged. SOLUTION: A recording paper detection circuit 410 has a counter inside, starts counting in accordance with output from a paper leading edge sensor 347, and fetches the counted value by the counter in timing when the change of the transfer voltage of each electrifier is detected. Then, the delay amount of a delay part 206 is decided and stored in a memory 411. A transfer electrifier 323 is controlled in terms of constant current through a transfer current control circuit 403 and the change of impedance occurring because the recording paper reaches the electrifier 323 is shown as the change of transfer voltage. By detecting the change of the transfer voltage at the time of carrying the recording paper, the recording paper is detected at the transfer position. The delay amount for the images on four photoreceptor drums is decided according to the measured time at such a time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus provided with a transfer charging means for transferring a developer developed on an image carrier to a recording sheet fed.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine, when recording paper is delivered by a motor, rollers, or the like, the recording paper is detected at various positions to control various paper feeding operations and to perform a copy process. Power supply control required for

At this time, the detection of the recording paper has been performed by detecting optical interruption or reflection using an optical element such as a photo interrupter.

[0004]

However, when arranging a photointerrupter or the like in the apparatus, there are some places where the installation position is limited spatially or there are places where optical detection is impossible.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the first to ninth inventions according to the present invention is to monitor a power supply fluctuation state of a transfer charging unit. An image which can be used as a sensor unit for detecting a recording medium fed at a position where a transfer unit is disposed, and for controlling image forming timing, jam control of the recording medium, and registration correction control. It is an object to provide a forming device.

[0006]

According to a first aspect of the present invention, there is provided a transfer unit for transferring an image developed on an image carrier to a recording medium to be conveyed, and a power supply supplied to the transfer unit. A monitoring unit that monitors a state; and a detection unit that detects a paper feeding state of the recording medium with respect to the transfer unit from a power fluctuation state monitored by the monitoring unit.

According to a second aspect of the present invention, there is provided a first control means for controlling an image forming timing for the image carrier based on a detection result of the detection means.

According to a third aspect of the present invention, there is provided a second control means for controlling a feeding state of the recording medium based on a detection result of the detection means.

According to a fourth aspect of the present invention, the second control means determines a paper feed jam from a feeding state of the recording medium based on a detection result of the detection means.

According to a fifth aspect of the present invention, there are provided a plurality of transfer means for sequentially superimposing and transferring images formed on a plurality of image carriers arranged side by side onto a fed recording medium, and Monitoring means for monitoring a power fluctuation state supplied to the means;
Detecting means for detecting a feeding state of the recording medium to each transfer means from a power fluctuation state monitored by the monitoring means.

According to a sixth aspect of the present invention, there is provided a first control means for individually adjusting the image forming timing for each image carrier based on the detection result of the detection means.

According to a seventh aspect of the present invention, the first control means individually adjusts the image forming timing for each image carrier based on the detection result of the detection means to adjust the image forming timing on each image carrier. The image writing position is corrected.

An eighth invention according to the present invention is provided with second control means for controlling the feeding state of the recording medium based on the detection result of the detection means.

In a ninth aspect according to the present invention, the second control means determines a paper feed jam from a feeding state of the recording medium based on a detection result of the detection means.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

[First Embodiment] FIG. 1 is a schematic cross-sectional view illustrating the configuration of a color image forming apparatus according to a first embodiment of the present invention, and corresponds to, for example, an image processing apparatus that performs LED exposure in a quadruple tandem system. The present invention can be applied to a case where the image exposure source is not limited to the LED array but is a laser. The image processing apparatus includes a reader unit 300 and a printer unit 362.

In the reader section 300, 101 is a CCD
An original image is converted into an electric signal by an image sensor (CCD). 311 is a substrate on which the CCD 101 is mounted;
Reference numeral 312 denotes an image processing unit, which will be described later in detail. 301 is a platen glass (platen), 302 is a document feeder (DF)
The lower surface of the document feeder 302 is a mirror surface pressure plate.

Reference numerals 303 and 304 denote light sources (halogen lamps or fluorescent lamps) for illuminating the original, 305 and 306 deflectors for condensing the light from the light sources 303 and 304 on the original,
7, 308 and 309 are mirrors; 310 is a lens for condensing reflected light or projection light from the original on the CCD 101;
A carriage 14 accommodates the halogen lamps 303 and 304, the reflectors 305 and 306, and the mirror 307. 31
5 is a carriage that houses the mirrors 308 and 309, 31
An interface (I / F) unit 3 inputs and outputs image signals to and from an external device. Reference numeral 316 denotes a driving unit, and the carriage 31
4,315 is driven. Reference numeral 361 denotes an operation unit of the apparatus.

When the moving speed of the carriage 314 is V, the driving of the carriage 315 is controlled by the driving unit 316 so as to have a moving speed of V / 2. The setting of the moving speed is determined based on the setting of the optical path length.
The carriages 315 and 316 are controlled to scan (sub-scan) the entire surface of the document by mechanically moving in a direction perpendicular to the electrical scanning (main scanning) direction of the CCD 101.

Next, regarding the configuration of the printer unit 362,
This will be described in detail.

In the printer section 362, 317 is an M image forming section for forming an M image, 318 is a C image forming section for forming a C image, 319 is a Y image forming section for forming a Y image, and 320 is a K image forming section. A K image forming unit for forming an image of
Since each configuration is the same, the M image forming unit 317 will be described in detail, and description of the other image forming units will be omitted.

In the M image forming unit 317, reference numeral 342 denotes a photosensitive drum, on which a latent image is formed by light from the LED array 214. A primary charger 321 charges the surface of the photosensitive drum 342 to a predetermined potential to prepare for forming a latent image. A developing unit 322 containing magenta toner develops a latent image on the photosensitive drum 342 to form a toner image. Note that the developing device 322 includes a sleeve 353 for applying a developing bias to perform development. Reference numeral 323 denotes a transfer charger, which discharges electricity from the back of the transfer belt 333 to form a toner image on the photosensitive drum 342.
The image is transferred to recording paper on the transfer belt 333. In the present embodiment, a cleaner portion is not provided because transfer efficiency is high, but it goes without saying that there is no problem even if the cleaner portion is attached.

Next, a procedure for forming an image on a recording sheet will be described.

The recording paper stored in the cassettes 340 and 341 is supplied onto the transfer belt 333 by paper feed rollers 336 and 337 one by one by pickup rollers 338 and 339. The fed recording paper is charged by the adsorption charger 346. Reference numeral 348 denotes a transfer belt roller which drives the transfer belt 333 and charges the recording paper or the like in a pair with the attraction charger 346 to attract the recording paper or the like to the transfer belt 333. Reference numeral 347 denotes a paper edge sensor, which is a transfer belt 333.
Detect the leading edge of the upper recording paper or the like. Note that the paper tip sensor 3
The detection signal of 47 is sent from the printer unit 362 to the reader unit 300.
To the drive unit 316. This signal is used as a sub-scanning synchronization signal, and based on this signal, the driving unit 316 is used.
Drives the carriages 314 and 315 described above,
D101 is driven.

Thereafter, the recording paper is conveyed by a transfer belt 333, and is transferred to the image forming units 317 to 320 by the MC.
A toner image is formed on the surface in the order of YK. The recording paper that has passed through the K image forming unit 320 is discharged from the transfer belt 333 after being discharged by the discharging charger 349 in order to facilitate separation from the transfer belt 333. Reference numeral 350 denotes a peeling charger, which prevents image disturbance due to peeling discharge when recording paper or the like is separated from the transfer belt 333. The separated recording paper or the like is charged by pre-fixing chargers 351 and 352 and then heat-fixed by a fixing device 334 to fix the toner image 335 in order to compensate for toner attraction and prevent image disturbance. Is discharged to the paper discharge tray.

FIG. 2 is a block diagram showing a detailed configuration of the image processing unit 312 shown in FIG. 1. The same components as those in FIG. 1 are denoted by the same reference numerals. FIG. 3 is a block diagram illustrating a configuration of the printer processing unit of the printer unit 362 illustrated in FIG. Hereinafter, the configuration and operation will be described.

The original on the original platen glass 301 shown in FIG. 1 reflects light from the light sources 303 and 304, and the reflected light is guided to the CCD 101 and converted into an electric signal. CCD
Reference numeral 101 denotes a three-line CCD in which R, G, and B filters are independently provided. The R, G, and B line CCDs are arranged with a predetermined offset. The three-line CCD is fixed as shown in FIG. 1, and when the carriages 314 and 315 move, reflected light of the original image is incident on the CCD 101 and the original image is read. The document position read at the same timing with respect to the document set on the glass 301 has a certain offset. The electric signal (analog image signal) converted by the CCD 101 is input to the image processing unit 312. The signal input to the image processing unit 312 is the signal of the clamp & Amp. The sample and hold (S / H) is performed by the & S / H & A / D unit 102, and the dark level of the analog image signal is clamped to the reference potential.

Thereafter, the signal is amplified to a predetermined amount (the processing order is not limited to the notation order), A / D converted, and
It is converted into a digital signal of 8 bits for each GB and output. Clamp & Amp. The RGB signals output from the & S / H & A / D unit 102 are subjected to shading correction and black correction by a shading unit 103, and then connected and connected.
It is input to an MTF (Medulation Transfer Function) correction & original detection unit 104. The connection & MTF correction & original detection unit 104 has a CC composed of RGB 3-line CCDs arranged with a predetermined offset as described above.
By adjusting the amount of delay given to the read signal read by each line CCD in D101 for each line, the signal timing is corrected so that the read positions of the three lines become the same.

In the MTF correction, since the reading MTF changes depending on the reading speed and the magnification, the change is corrected, and the document detection scans the document on the platen glass 301 to confirm the document size. The input masking unit 105 corrects the spectral characteristics of the CCD 101 and the spectral characteristics of the light sources 303 and 304 and the reflectors 305 and 306 on the digital signal whose read position timing has been corrected. The output of the input masking unit 105 is input to a selector 106 that can be switched with an external I / F signal from an external I / F unit 114. The signal output from the selector 106 is subjected to a color space compression & background removal & LOG conversion unit 107 and a background removal unit 115.
Is input to After the signal input to the background removal unit 115 is removed from the background, the signal is input to a black character determination unit 116 that determines whether or not the document is a black character in the document, and a black character signal is generated from the document.

The color space compression / background removal / LOG converter 107 to which the output of the other selector 106 is input.
Then, color space compression determines whether the read image signal is within the range that can be reproduced by the printer, and if so, corrects it so that the image signal is within the range that can be reproduced by the printer. . Then, a background removal process is performed, and the CMY signals are converted from the RGB signals by LOG conversion.
Convert to a signal.

Then, the timing of the output signal of the color space compression / background removal / LOG conversion unit 107 is adjusted by a delay 108 in order to correct the signal generated by the black character determination unit 116 and the timing. These two types of signals are used as the moiré removing unit 1
At 09, the moiré is removed, and the scaling processing unit 110 performs scaling processing in the main scanning direction. 111 is UCR & Masking &
CMY processed by the scaling unit 110 in the black character reflection unit
The signal is generated as a CMYK signal by the UCR process, corrected by the masking processing unit to a signal output from the printer, and the determination signal generated by the black character determination unit 116 is fed back to the CMYK signal. The signal processed by the UCR & masking & black character reflection unit 111 is subjected to density adjustment by the γ correction unit 112 and then subjected to smoothing or edge processing by the filter unit 113. The signal processed as described above is converted from an 8-bit multilevel signal to a binary signal by a binary conversion unit 201 shown in FIG.
Any of the error diffusion method and the improved error diffusion method may be used.)

FIG. 3 is a block diagram for explaining a data processing configuration of the printer unit 362 shown in FIG.

In the figure, a binary conversion unit 201 converts an 8-bit multi-level signal into a binary signal (the conversion method may be any of a dither method, an error diffusion method, and an improved error diffusion method). .

The binary C output from the binary converter 201
The MYK signal is input to the buffer units 202 to 205,
These are input to the delay units 206, 207, 208, and 209, respectively, are given a predetermined delay, and print four colors at predetermined positions by adjusting the difference in the distance between the leading edge of the paper and each image forming unit. It becomes possible. Delay unit 20
6, 207, 208, and 209 are input to the LED driving units 210, 211, 212, and 213, and output signals of the respective driving units are used to form an LED array that is a block of a printer unit described later. Part 21
4, 215, 216, and 217 are configured to be driven.

Hereinafter, a drive control circuit of the transfer chargers 323, 326, 329 and 332 shown in FIG. 1 will be described with reference to FIG. The transfer chargers 323, 32
6, 329 and 332 are the same, and the transfer charger 323 will be described as an example.

FIG. 4 shows the transfer charger 323 shown in FIG.
It is a circuit block diagram which shows an example of a drive control circuit of 326,329,332.

In the drawing, 401 is a flyback transformer for generating a transfer voltage, L1 is a power supply side winding, L2
Is a load side winding, and L3 is a voltage monitoring auxiliary winding. 4
A transistor 02 switches a current from the DC power supply VDD to the flyback transformer 401. 403
Is a transfer current control circuit that performs PWM control on the transistor 402 based on the detection value of the transfer current detection resistor 404 so that the transfer current becomes constant.

The flyback voltage generated in the power supply winding L1 is transmitted to the load winding L2, smoothed by the rectifying diode 412 and the smoothing capacitor 405, and supplied to the transfer charger 323.

Reference numeral 406 denotes a resistor for discharging the smoothing capacitor 405, and 407 denotes a leak protection resistor.

A recording paper detection circuit 410 is provided with a voltage monitoring auxiliary winding L3 for facilitating the monitoring of the transfer voltage. The voltage is reduced, and then the voltage is smoothed by a rectifying diode 408 and a smoothing capacitor 409. Monitor the voltage. The recording paper detection circuit 410 has a counter inside, and starts counting in accordance with the output of the paper leading edge sensor 347, as described later, and operates at the timing when a change in the transfer voltage of each charger is detected. Capture the count value. Further, the delay amount of the delay unit 206 shown in FIG. 3 (the delay amount for adjusting the difference between the position of the leading edge of the paper and the distance between each image forming unit) is determined and stored in the memory 411.

In the first embodiment, the transfer charger 323 is
The constant current control is performed via the transfer current control circuit 403, and the impedance change due to the recording paper reaching the transfer charger 323 appears as a change in the transfer voltage.
This change is shown in FIG.

FIG. 5 is a characteristic diagram showing a change in the transfer voltage due to the arrival of the recording paper at the transfer charger 323 shown in FIG. 4. The vertical axis shows the transfer voltage, and the horizontal axis shows time.

In the first embodiment, the transfer charger 323 has an impedance of about 1000 MΩ and a transfer current of 1 μA.
And a transfer voltage of about 1000 V is generated. The impedance change due to the recording paper reaching the transfer charger 323 is about 10% in absolute value. In the first embodiment, the time when the impedance changes due to the change of 5% is defined as the recording paper arrival point.

Although only the transfer charger 323 and the delay unit 206 are shown in FIG. 4, the transfer unit 326 and the delay unit 207, the transfer unit 329 and the delay unit 208, and the transfer unit 33
2 and the delay unit 209. Further, the delay amount is stored in the memory 411 and is applied at the next time of forming an image on a recording sheet.

Hereinafter, the processing for determining the delay amount of the delay units 206 to 209 shown in FIG. 3 will be described with reference to the timing chart shown in FIG.

FIG. 6 shows the transfer charger 323 shown in FIG.
6 is a timing chart showing transfer voltage changes of 326, 329, and 332.

As described above, the recording paper detection circuit 410 (internal counter) starts timing when the paper leading edge sensor 347 detects the leading edge of the recording paper sent from the paper feed rollers 336 and 337. . Next, the intermediate time value at the timing when the transfer voltage change is detected by the transfer charger 323 is represented by “T
1 ". Similarly, the intermediate time value of the transfer charger 326 is set to “T2”, the intermediate time value of the transfer charger 329 is set to “T3”, and the time value of the transfer charger 332 is set to “T4”.
And The measured time values T1, T2, T3, and T4 are the delay time values TT1, TT2, TT3, and TT4 of the delay units 206, 207, 208, and 209, respectively. After completion of the clocking, the clocking time values T1, T2, T3, and T4 are stored in the memory 411 shown in FIG. 4 and applied at the next time of forming an image on a recording sheet. It is updated when the switch is turned on.

The toner image is formed on the surface of the recording paper conveyed by the transfer belt 333 in the image forming units 317 to 320 in the order of MCYK. Then, the images of the respective drums are accurately aligned based on the delay time values TT1, TT2, TT3, and TT4. The recording paper that has passed through the K image forming unit 320 at the last stage is transferred to the transfer belt 333.
In order to facilitate separation from the transfer belt 331, the toner is removed from the transfer belt 333 after the charge is removed by the charge removal charger 349.

As described above, the change in the transfer voltage when the recording paper is conveyed is detected, and the recording paper can be detected at the transfer position. At this time, the amount of delay for the images of the four photosensitive drums is determined based on the measured time. As a result, even if there is a temporal change such as the paper conveyance speed or the distance between the drums, the image positional relationship at the transfer position is self-adjusted, and the image positions among the four photosensitive drums can be matched.

[Second Embodiment] In the first embodiment,
A case has been described in which the voltage change of the transfer chargers 323, 326, 329, and 332 is monitored to adjust the image position by delaying the image recording timing.
3, 326, 329 and 332 may be monitored to determine whether a jam has occurred. Hereinafter, the embodiment will be described. That is, in the second embodiment, in an image forming apparatus that forms a color image using four photosensitive drums, it is detected that the recording paper has reached the transfer position by observing (monitoring) a voltage change of the transfer charger. The JAM (paper jam) state is determined by using this method.

FIG. 7 is a block diagram for explaining a main configuration of an image forming apparatus according to a second embodiment of the present invention.

In the figure, 501 is a flyback transformer for generating a transfer voltage, L4 is a power supply side winding, L5
Is a load side winding, and L6 is a voltage monitoring auxiliary winding. 5
A transistor 02 switches the current from the DC power supply VDD to the flyback transformer 501. 503
Is a transfer current control circuit that performs PWM control on the transistor 502 based on the detection value of the transfer current detection resistor 504 so that the transfer current becomes constant.

The flyback voltage generated at the power supply winding L4 is transmitted to the load winding L5, smoothed by the rectifier diode 512 and the smoothing capacitor 505, and supplied to the transfer charger 323.

Reference numeral 506 denotes a resistor for discharging the smoothing capacitor 505, and 507 denotes a leak protection resistor.

Reference numeral 510 denotes a recording paper detection circuit, which is provided with a voltage monitoring auxiliary winding L6 for facilitating the monitoring of the transfer voltage. Monitor the voltage. 5
Reference numeral 11 denotes a sequence controller, which is a CPU (not shown).
The apparatus includes a RAM and a ROM, and determines the occurrence state of the recording paper conveyance jam based on the recording paper detection timing (shown in FIG. 8) of the recording paper detection circuit 510, and controls the stop of the image forming sequence and the warning display. The sequence controller 511 generally controls a normal image forming sequence.

In the second embodiment, as in the first embodiment, the transfer chargers 323, 326, 329, and 332 are
The constant current control is performed, and the impedance change due to the recording paper reaching the transfer charger appears as a change in the transfer voltage (see FIG. 5). The transfer chargers 323, 3
26, 329, 332 have an impedance of about 100
The transfer current is 0 MΩ, the transfer current is 1 μA, and a transfer voltage of about 1000 V is generated. Recording paper is transferred to chargers 323 and 32
The impedance change due to reaching 6,329,332 is about 10% in absolute value, and in the second embodiment, the changed level of 5% or more is set as the recording paper detection level.

Although FIG. 7 shows only the transfer charger 323, the transfer chargers 326, 329, 33
The same applies to No. 2.

When the recording paper is detected, the information is transmitted to the sequence controller 511, and the sequence controller 511 determines the JAM according to the timing shown in FIG.

FIG. 8 shows the recording paper detection circuit 51 shown in FIG.
6 is a timing chart for explaining a recording paper detection timing by 0.

When image formation is started by the sequence controller 511, the recording paper is picked up by the pickup roller 33.
8, 339, the sheet is supplied onto the transfer belt 333 by sheet feed rollers 336, 337. In the second embodiment, the conveyance speed of the fed recording paper is 100 mm / sec.
Then, from the paper leading edge sensor 347 shown in FIG.
23 is 50 mm, the distance from the transfer charger 323 to the transfer charger 326 is 100 mm,
6 is 100 mm, and the distance from the transfer charger 329 to the transfer charger 332 is 100 mm.
mm.

The sequence controller 511 checks the detection level of the transfer charger 323 0.7 sec after the paper leading edge sensor 347 detects the recording paper, and makes a JAM determination. Next, the detection level of the transfer charger 326 is checked 1.7 seconds after the paper leading edge sensor 347 detects the recording paper, and the JAM is determined. Next, the paper edge sensor 3
The detection level of the transfer charger 329 is checked 2.7 sec after the detection of the recording paper by the 47, and the JAM is determined.

Next, 3.7 seconds after the paper edge sensor 347 detects the recording paper, the detection level of the transfer charger 332 is checked, and JAM judgment is made.

As described above, the change in the transfer voltage when the recording paper is conveyed is detected, and the recording paper can be detected at the transfer position. By performing this at a predetermined timing, it is possible to determine the occurrence of JAM without using a detecting unit such as an optical sensor.

Hereinafter, the correspondence between the first and second embodiments and the respective means of the first to ninth aspects and the operation thereof will be described with reference to FIG.

According to a first aspect of the invention, a transfer means (transfer charger 323) for transferring an image developed on an image carrier to a recording medium to be conveyed, and a power supply state supplied to the transfer means is monitored. Monitoring means (flyback transformers 401 and 5)
01, monitoring the transfer voltage fluctuation state via the voltage monitoring auxiliary windings L3, L6) and detecting means for detecting the feeding state of the recording medium to the transfer means from the power fluctuation state monitored by the monitoring means. (Recording paper detection circuits 410 and 51
0), and the paper feed state of the recording medium to the transfer charger 323 is detected from the power supply fluctuation state monitored by the recording paper detection circuits 410 and 510. Therefore, the transfer charger 323 is used as a part of the paper feed sensor. Can work.

According to the second aspect, the first control means (such as the delay unit 206) controls the image forming timing on the image carrier based on the detection result of the recording paper detection circuit 410. By functioning as a part of a paper feed sensor, an image forming position with respect to a recording medium can be adjusted.

According to the third aspect of the present invention, since the second control means (sequence controller 511) controls the feeding state of the recording medium based on the detection result of the recording paper detecting circuit 510, the transfer charger 323 is fed. By functioning as a part of the sensor, it is possible to monitor and control the state of feeding the recording medium.

The fourth invention is a sequence controller 5
11, a paper feed jam is determined from the feeding state of the recording medium based on the detection result of the recording paper detection circuit 510;
By making the transfer charger 323 function as a paper feed sensor and monitoring the feeding of the recording medium, a paper feed jam can be detected and determined.

According to a fifth aspect of the present invention, a plurality of transfer means (for transferring images formed on a plurality of image carriers (photosensitive drums 342 to 345) arranged side by side on a recording medium to be successively superimposed on each other). (Transfer chargers 323, 326, 329, 332)
Monitoring means for monitoring the power supply fluctuation state supplied to each transfer means (monitoring the transfer voltage fluctuation state via the voltage monitoring auxiliary windings L3 and L6 of the flyback transformers 401 and 501 (in the figure, the photosensitive drum) 342 only)))
And detecting means (recording paper detection circuits 410 and 510) for detecting a paper feeding state of the recording medium for each transfer means from a power fluctuation state monitored by the monitoring means. Are the transfer chargers 323, 32
6, 329, 332, the paper feeding state of the recording medium is detected, so that each of the transfer chargers 323, 326, 329,
332 can function as a part of each paper feed sensor.

According to a sixth aspect of the present invention, the first control means (the delay units 206 to 209 of the printer processing unit) individually sets the image forming timing for each of the photosensitive drums 342 to 345 based on the detection result of the recording paper detection circuit 410. Since the adjustment is performed, each transfer unit can function as a paper feed sensor, and the image forming position on each image carrier with respect to the recording medium can be adjusted.

According to a seventh aspect of the present invention, the delay units 206 to 209
Each of the photosensitive drums 342 based on the detection result of the detection unit
To 345 are individually adjusted to correct the image writing position on each of the photosensitive drums 342 to 345, so that each of the transfer chargers 323, 326, 329,
332 can function as a part of the paper feed sensor, and the registration on each of the photosensitive drums 342 to 345 can be matched.

According to the eighth invention, the second control means (sequence controller 511) controls the feeding state of the recording medium based on the detection result of the recording paper detecting circuit 510, so that each of the transfer chargers 323, 326 is controlled. , 329 and 332 function as a part of the paper feed sensor, and can monitor and control the feeding state of the recording medium.

The ninth aspect of the present invention relates to the sequence controller 5
11, a paper feed jam is determined from the feeding state of the recording medium based on the detection result of the recording paper detection circuit 510;
Each of the transfer chargers 323, 326, 329, and 332 can function as a paper feed sensor to monitor the feeding of the recording medium and detect and determine a paper feed jam.

The present invention may be applied to a system composed of a plurality of devices or to an apparatus composed of one device. Needless to say, the present invention can be applied to a case where the present invention is achieved by supplying a program to a system or an apparatus. In this case, by reading a storage medium storing a program represented by software for achieving the present invention into the system or the apparatus, the system or the apparatus can enjoy the effects of the present invention. .

Further, by reading and reading a program represented by software for achieving the present invention from a database on a network by a communication program, the system or apparatus can be
It is possible to enjoy the effects of the present invention.

According to each of the above embodiments, a change in transfer control (a change in impedance, a change in transfer current, a change in transfer voltage, etc.) to the transfer charger to which the recording paper is conveyed is detected, and the recording medium is indirectly detected. can do. Therefore, the recording medium can be detected at the position where the transfer charger is disposed (the position where it is conventionally difficult to attach the feeding sensor). Further, various controls, such as registration correction control and paper feed jam detection control, can be executed in accordance with the detected timing of the recording medium.

[0076]

As described above, the first embodiment according to the present invention is described.
According to the invention, since the detecting means detects the paper feeding state of the recording medium to the transfer means from the power fluctuation state monitored by the monitoring means, the transfer means can function as a paper feed sensor.

According to the second aspect, the first control means controls the image forming timing on the image carrier based on the detection result of the detection means, so that the transfer means functions as a paper feed sensor. The image forming position on the recording medium can be adjusted.

According to the third aspect, the second control means controls the feeding state of the recording medium based on the detection result of the detection means, so that the transfer means functions as a paper feed sensor, Can be monitored and controlled.

According to the fourth aspect of the present invention, the second control means determines the paper feed jam from the feeding state of the recording medium based on the detection result of the detection means. And feed monitoring of the recording medium can be monitored to detect and determine a paper feed jam.

According to the fifth aspect, since the detecting means detects the paper feeding state of the recording medium to each transfer means from the power fluctuation state monitored by the monitoring means, each transfer means functions as each paper feed sensor. be able to.

According to the sixth aspect, the first control means individually adjusts the image forming timing for each image carrier based on the detection result of the detection means, so that each transfer means functions as a paper feed sensor. Thus, it is possible to adjust the image forming position of each image carrier with respect to the recording medium.

According to the seventh aspect, the first control means individually delay-adjusts the image forming timing for each image carrier based on the detection result of the detection means and controls the image formation on each image carrier. Since the writing position is corrected, each transfer unit can function as a paper feed sensor, and the registration on each image carrier can be matched.

According to the eighth aspect, the second control means controls the feeding state of the recording medium on the basis of the detection result of the detection means. The feeding state of the medium can be monitored and controlled.

According to the ninth aspect, the second control means determines the paper feed jam from the feeding state of the recording medium based on the detection result of the detection means. By functioning as a sensor, the feeding of the recording medium can be monitored to detect and determine a paper feed jam.

Therefore, the recording medium fed at the position where the transfer means is disposed is detected, and the recording medium is combined and used as a sensor unit for controlling image formation timing, controlling the jam of the recording medium, and controlling registration correction. It has effects such as being able to do.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view illustrating a configuration of a color image forming apparatus according to a first exemplary embodiment of the present invention.

FIG. 2 is a block diagram illustrating a detailed configuration of an image processing unit illustrated in FIG. 1;

FIG. 3 is a block diagram illustrating a configuration of a printer processing unit of the printer unit illustrated in FIG.

FIG. 4 is a circuit block diagram showing an example of a drive control circuit of the transfer charger shown in FIG.

FIG. 5 is a characteristic diagram showing a transfer voltage change due to a recording sheet reaching the transfer charger shown in FIG. 4;

FIG. 6 is a timing chart showing a transfer voltage change of the transfer charger shown in FIG.

FIG. 7 is a block diagram illustrating a main configuration of an image forming apparatus according to a second exemplary embodiment of the present invention.

FIG. 8 is a timing chart illustrating recording paper detection timing by the recording paper detection circuit shown in FIG. 7;

[Explanation of symbols]

 323 Transfer charger 401 Flyback transformer 410 Recording paper detection circuit 411 Memory 206 Delay unit L3 Voltage monitoring auxiliary winding L6 Voltage monitoring auxiliary winding

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Naohisa Nagata 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Toshihiko 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inside (72) Inventor Shigemi Kumagai 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Takahiro Incorporated 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. ( 72) Inventor Yoshio Komaki 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Shigeo Yamagata 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (9)

[Claims] A transfer means for transferring an image developed on an image carrier to a recording medium to be conveyed; a monitoring means for monitoring a power supply state supplied to the transfer means; An image forming apparatus comprising: a detection unit configured to detect a paper supply state of the recording medium to the transfer unit from a power supply fluctuation state. 2. The image forming apparatus according to claim 1, further comprising a first control unit that controls an image forming timing on the image carrier based on a detection result of the detection unit. 3. The image forming apparatus according to claim 1, further comprising a second control unit that controls a feeding state of the recording medium based on a detection result of the detection unit. 4. The image forming apparatus according to claim 3, wherein the second control unit determines a paper feed jam from a feeding state of the recording medium based on a detection result of the detection unit. 5. A plurality of transfer means for sequentially superimposing and transferring images formed on a plurality of image carriers arranged side by side on a fed recording medium, and a power fluctuation state supplied to each transfer means An image forming apparatus comprising: a monitoring unit that monitors the paper supply state of the recording medium with respect to each transfer unit from a power supply fluctuation state that is monitored by the monitoring unit. 6. The image forming apparatus according to claim 5, further comprising a first control unit that individually adjusts an image forming timing for each image carrier based on a detection result of the detection unit. 7. The image processing apparatus according to claim 1, wherein the first control unit corrects an image writing position on each image carrier by individually delay adjusting an image forming timing for each image carrier based on a detection result of the detection unit. The image forming apparatus according to claim 6, wherein: 8. The image forming apparatus according to claim 5, further comprising a second control unit that controls a feeding state of the recording medium based on a detection result of the detection unit. 9. The image forming apparatus according to claim 8, wherein the second control unit determines a paper feed jam from a feeding state of the recording medium based on a detection result of the detection unit.