JP3512570B2 - Image forming device - Google Patents

Description

Detailed Description of the Invention TECHNICAL FIELD OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly to prevention of defective image generation when image formation is restarted.

[0002]

2. Description of the Related Art In a color copying machine which superimposes an image on an intermediate transfer member and outputs color superimposition, a scanner exposure lamp of a scanner is turned on when a reference mark for color superimposition is detected, and the amount of light generated by the scanner exposure lamp is increased. The scanning scan was started after measuring a constant time required for the value to reach a predetermined value and stabilize. Then, after a lapse of the forward movement time of the scanner determined by the size of the original and the copy magnification, the scanner exposure lamp is turned off and the scanner is restored. In this way, since the scanner exposure lamp timed the stable time of the scanner to start the scanning, the scanning timing was shifted due to an error of the timer or the like which measured the stable time of the scanner exposure lamp, and the toner image of each color was There was a case where it slipped.

On the other hand, in the color copying machine disclosed in Japanese Patent Laid-Open No. 3-186866, the scanner exposure lamp is turned on based on the detection of the mark for the previous image formation as shown in FIG. Then, the output of the scanner exposure lamp is stabilized, and the scanning is started based on the detection of the mark serving as the reference for starting the image formation, whereby the deviation of the toner image of each color is prevented.

[0004]

However, in the above-mentioned color copying machine, it is not possible to know in advance when the mark is detected in the image formation of the first color, and therefore the scanner exposure lamp is started at the same time when the pretreatment of the image formation is started. Was turned on, or turned on after a lapse of a predetermined delay time, or the intermediate transfer member was rotated one extra time before image formation to obtain the timing.

If the intermediate transfer member is rotated one extra time, the output time of one transfer sheet is delayed. If the positional relationship between the reference mark and the mark sensor that detects the reference mark depending on the stop position of the intermediate transfer member is not managed, the lighting time of the scanner exposure lamp may be short, which may cause uneven density. In addition, there is a possibility of lighting more than necessary, which will affect the life of the lamp.

Further, when the exposure timing of the next color is generated from the detection of the reference mark of the image formation of the previous color, for example, when the expansion mode is set when the memory is not used, If the image forming interval between the previous color and the next color is long, the intermediate transfer member will rotate many times. Has a short stabilization time with respect to the charged state of the photoconductor, which may cause uneven density.

The present invention has been made to solve the above disadvantages, and an object thereof is to improve the quality of a formed image.

[0008]

An image forming apparatus according to the present invention comprises a relative position detecting means, a mark detecting time predicting means and a time comparing means, and the relative position detecting means indicates a mark moving position and a mark for alignment. The relative position relationship with the position of the mark sensor to be detected is detected and stored, and the mark detection time predicting means is a mark sensor for detecting the position and the mark moving position for alignment detected by the relative position detecting means at the start of image formation. predicting a time from the relative positional relationship to the detection of the mark for alignment and the position of the termination Sequence
If a command to start the next image formation comes during
The time comparison means compares the time until the mark for alignment is detected by the mark detection time prediction means with the time until the photosensitive member is in a stable charged state, and the time until the alignment mark is detected. If time photoreceptor is shorter than the time required to stabilize it is to a mark detection signal from Ma Kusensa avoid a reference for transfer to the photoconductor of the image, the photosensitive before the charged state of the photosensitive member is stabilized Prevents the transfer of images to the body.

Further, the image forming apparatus is provided with a relative position detecting means, a mark detecting time predicting means and a time comparing means, and the relative position detecting means is a mark stop position and a mark for position alignment when the intermediate transfer member is stopped emergency. The mark detection time predicting means detects the relative positional relationship with the position of the mark sensor, and the mark detection time predicting means detects the mark stop position for alignment detected by the relative position detecting means at the start of image formation and the mark for detecting the mark. It predicts a time until detecting the mark for positioning the relative positional relationship between the position of the sensor, exit
-If the motion suddenly stopped during the
When an image formation start command is received at the stop position
In addition, the time comparison means detects the alignment mark by comparing the time until the mark detection time prediction means detects the alignment mark predicted by the mark detection time prediction means with the time until the photosensitive member is in a stable charged state. If the time until is shorter than the time until the photosensitive body is stable, and a mark detection signal from Ma Kusensa avoid a reference for transfer to the photoconductor of the image, after the intermediate transfer member has an emergency stop It prevents the transfer of an image to the photoconductor before the charged state of the photoconductor is stabilized.

Furthermore, the relative position detection means or a moving distance and the mark sensor one round mark for positioning that comes with the intermediate transfer member to detect the mark for alignment et al
Position detecting relative positions of the mark and the mark sensor for positioning the moving distance to the mark moving position for location registration. Or, when the intermediate transfer body stops in an emergency, the relative position
The detection means is the alignment marker attached to the intermediate transfer member.
The mark sensor is used to align the movement distance of one round
Position from when the mark is detected until the intermediate transfer body stops
From the moving distance of the alignment mark to the alignment mark
The relative position of the mark sensor is detected.

Further, when the end sequence is normally completed, the relative positional relationship between the alignment mark and the mark sensor for detecting the mark is always the same, and the image formation start instruction is input before the image is formed. The time until transfer is kept constant, and a stable and good image is formed.

Further, the mark detection time predicting means next detects the alignment mark from the relative positional relationship between the position of the alignment mark moving position detected by the relative position detection means and the position of the mark sensor for detecting the mark. And the time until the detection of the mark for alignment that serves as a reference for forming an image is predicted, and the time comparison means detects the mark for alignment that serves as a reference for forming the image predicted by the mark detection time prediction means. from the time until the scanner, the document
The exposure timing of the exposure lamp that exposes the document to optically read the image is determined to ensure the minimum time required for the exposure lamp of the scanner to stabilize. Alternatively,
Mark detection time prediction method when the intermediate transfer body stops in an emergency
Is a mark stop for alignment detected by the relative position detection means.
Relative between the stop position and the position of the mark sensor that detects the mark
Next, the alignment mark is detected from the physical positional relationship.
For alignment as a reference until time and image formation
The time comparison means predicts the time until
This is the standard for forming the image predicted by the
From the time until the mark for alignment is detected to the scanner
, Exposing the original to optically read the original image
The exposure timing of the exposure lamp
EXPOSURE lamp to ensure a minimum time required to stabilize.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The image forming apparatus of the present invention forms an image on a photoconductor with reference to the detection of alignment marks attached to the intermediate transfer body, and forms the formed image on the intermediate transfer body. In an image forming apparatus that performs transfer and transfer from an intermediate transfer member to a transfer paper, prevents transfer of the image to the photosensitive member before the charged state of the photosensitive member is stable, and waits until the image is transferred to the photosensitive member. It saves time.

Normally, the image forming apparatus does not leave a history such that an abnormal image is formed on the photosensitive member after the image is transferred onto the transfer paper, and the charging strocol charger (hereinafter referred to as "charging CH"). In order to turn off the developing bias and the developing bias sequentially according to the layout, the transfer body and the photoconductor are rotated for a while. The post-processing sequence after completion of image formation will be referred to as an end sequence.

When a command to start the next image formation is received during the end sequence, if the mark detection is always enabled without managing the mark detection timing, if the charging CH has already been turned off. Writing may be started before the stable charged area is formed on the photoconductor to cause density unevenness in the image.

Therefore, the image forming apparatus includes a relative position detecting means, a mark detection time predicting means, and a time comparing means. The relative position detecting means detects and stores the relative positional relationship between the mark moving position for position alignment and the position of the mark sensor that detects the mark. The mark detection time predicting means detects the alignment mark from the relative positional relationship between the position of the alignment mark moving position detected by the relative position detection means at the start of image formation and the position of the mark sensor for detecting the mark. Predict time. The next image shape during the end sequence
When a command to start the formation is received, the time comparison means compares the time until the mark detection time prediction means detects the alignment mark predicted with the time until the photosensitive body becomes a stable charged state. , if the time to detect the mark for alignment is shorter than the time until the photosensitive body is stable, and a mark detection signal from Ma Kusensa avoid a reference for transfer to the photoconductor of the image, It prevents the transfer of an image to the photoconductor before the charged state of the photoconductor is stabilized. In order to detect the relative positional relationship between the moving position of the alignment mark and the position of the mark sensor that detects the mark, the relative position detecting means detects one round of the alignment mark attached to the intermediate transfer member. The relative position detecting means stores the moving distance of one round of the positioning mark attached to the intermediate transfer member and the positioning mark after the mark sensor detects the positioning mark. The relative position of the alignment mark and the mark sensor is detected from the moving distance to the mark moving position. The moving distance from the mark sensor detecting the alignment mark to the alignment mark moving position is obtained from the count value of the encoder by providing a counter such as an encoder on the intermediate transfer member.

Further, during the sequence, for example, when the device is opened and the operation is suddenly stopped, it is unknown where the alignment mark is stopped, and if the mark detection is always enabled, Similar to the case where the start command in the end sequence is received, there is a possibility that the image formation is started in a state where the photoconductor is not stable.

Therefore, the image forming apparatus is provided with a relative position detecting means, a mark detecting time predicting means and a time comparing means, and the relative position detecting means uses a mark stop position and a mark for position alignment when the intermediate transfer member is brought to an emergency stop. The mark detection time predicting means detects the relative positional relationship with the position of the mark sensor, and the mark detection time predicting means detects the mark stop position for alignment detected by the relative position detecting means at the start of image formation and the mark for detecting the mark. The time required to detect the alignment mark is predicted from the relative positional relationship with the position of the sensor . End
When the operation suddenly stopped during the end sequence, and
If a command to start image formation is received at the stop position,
In this case, the time comparing means compares the time until the mark for detecting alignment predicted by the mark detection time predicting means with the time until the photosensitive member is in a stable charged state, and detects the mark for aligning. If the time to is shorter than the time until the photosensitive body is stable, and a mark detection signal from Ma Kusensa avoid a reference for transfer to the photoconductor of the image, after the intermediate transfer member has an emergency stop The transfer of an image onto the photoconductor is prevented before the charge state of the photoconductor is stabilized. In order to detect the relative positional relationship between the mark stop position for position alignment and the position of the mark sensor for detecting the mark, the relative position detecting means detects one round of the position of the alignment mark attached to the intermediate transfer member. The moving distance of one minute is stored in advance, and the relative position detecting means detects the moving distance of one round of the positioning mark attached to the intermediate transfer member and the mark sensor detects the positioning mark, and then the intermediate transfer member. The relative position of the alignment mark and the mark sensor is detected from the moving distance of the alignment mark until the stop.
A counter such as an encoder is provided on the intermediate transfer member to obtain the count value of the encoder from the moving distance of the position adjustment mark from when the mark sensor detects the position adjusting mark to when the intermediate transfer member is stopped.

Further, when the end sequence is normally completed, the distance between the alignment mark and the mark sensor for detecting the mark is always the same, and from the input of the image formation start instruction to the image output. The time may be fixed. The stop position is determined based on the mark position predicting means detecting the mark position during the operation of the intermediate transfer member.

The image of the original for obtaining a color-superimposed image
The scanner exposure lamp was turned on after detecting the mark of the timing of the scanner exposure lamp that exposes the original to optically read the image, and the scanning scan was started after the delay time of the stable time had elapsed. In order to secure a time for stabilizing the exposure of the scanner exposure lamp in image formation, the number of revolutions of the intermediate transfer body, which is the image formation cycle for the first color, is increased. Therefore, the mark detection time predicting means as a reference for forming an image from the relative positional relationship between the stop position when the moving position <br/> location or the intermediate transfer member of the mark and the mark sensor for alignment has emergency stop The time until the mark for alignment is detected is predicted, and the time comparison means starts the exposure of the scanner exposure lamp by the time required at least for the exposure of the exposure lamp to be stable before the time predicted by the mark detection time prediction means. I did it.

[0021]

1 is a block diagram of an image forming apparatus according to an embodiment of the present invention. As shown in the figure, the image forming apparatus includes a printer 1, a scanner 2, a paper feeding unit 3, and a document feeder 4.
And a sorter 5. The printer 1, the scanner 2, the paper feeding unit 3, the document feeder 4 and the sorter 5 respectively have a printer control unit 100, a scanner control unit 200, a paper feed control unit 300, a document feeder control unit 400 and a sorter control as shown in FIG. The system control unit 800 controls the printing process, the image reading process, the paper feeding process, the document conveying process, and the sorting process under the control of the system control unit 800.

The printer controller 100 includes a CPU 101, a ROM 102, a RAM 103, a serial communication controller 104, a write control IC 105, as shown in FIG.
Laser light source control unit 106, IO controller 10
7, main motor 110, drum motor 111, developing motor 112, revolver motor 113, replenishment motor 11
4, a polygon motor 115, a mark sensor 150, a revolver home position sensor 151 (hereinafter referred to as “revolver HP sensor”), a fixing unit 160, a power supply unit 170, an electrometer circuit 180, and a toner adhesion amount sensor circuit 181. Hereinafter, the toner adhesion amount sensor is referred to as a P sensor. The CPU 101 is a part that controls the printer 1 according to a control program stored in the ROM 102 in advance. Further, the CPU 101 includes a relative position detecting means 101a, a mark detection time predicting means 101b, and a time comparing means 101c.
With. The relative position detecting means 101a detects and stores the relative positional relationship between the position of the mark movement for alignment and the position of the mark sensor 150 for detecting the mark for alignment shown in FIG. Mark detection time prediction means 101
b is the time until the alignment mark is detected from the relative positional relationship between the alignment mark movement position detected by the relative position detection unit 101a at the start of image formation and the position of the mark sensor 150 that detects the mark. Predict. The time comparison means 101c is the mark detection time prediction means 101b.
Compares the time required to detect the alignment mark predicted by the above with the time until the photoconductor 10 becomes a stable charged state, and stabilizes the photoconductor 10 time until the alignment mark is detected. If the time is shorter than the time to, the mark detection signal from the mark sensor 150 is controlled not to be used as a reference for forming an image on the photoconductor 10. The writing control IC 105 is connected to the laser light source control unit 106 and the polygon motor 115 to control the exposure of the image. The drum motor 111 drives the photoconductor 10 and the intermediate transfer member 30.

As shown in FIG. 4, the IO controller 107 has a register clutch (hereinafter referred to as "register C") on the output side.
L ”. ) 130, a manual feed CL 131, a manual feed pickup solenoid 132, a charge eliminating lamp 133, an intermediate transfer member cleaning contact / separation solenoid 134, and a lubricant application solenoid 135 are connected, and the registration sensor 1 is connected to the input side.
40, manual feed paper end sensor 141, black cartridge sensor 142, color cartridge sensor 143,
The door switch 144 and the paper discharge sensor 145 are connected.

Further, the printer 1 is used as a driving portion in FIG.
As shown in FIG. 3, the photoconductor 10 includes a revolver unit 20, which includes developing units 21, 22, 23, and 24 for KCMY (black, cyan, magenta, and yellow), an intermediate transfer body 30, and a writing unit 40.

A sequence for forming a full-color image in the normal mode with the image forming apparatus having the above configuration will be described with reference to the signal chart of FIG.

Upon receiving the image formation start command, the image forming apparatus turns on the charge eliminating lamp 11 and the drum motor 111 to start the image forming cycle. As a result, the photoconductor 10
Rotates counterclockwise, and the intermediate transfer member 30 rotates clockwise. When the portion of the photoconductor 10 in contact with the static elimination lamp 11 at the time of turning on the static elimination lamp 11 reaches the charging position, a charging scotron charger (hereinafter, referred to as “charging C
"H". ) Turn on 12. When the portion on which the charging CH12 is in contact reaches the developing position when the charging CH12 on the photoconductor 10 is turned on, the developing bias DC, the developing bias AC, and the developing motor 112 are turned on. Further, when the portion contacting the developing devices 21, 22, 23, and 24 when the developing bias on the photoconductor 10 is turned on reaches the image transfer position to the intermediate transfer member, a belt transfer charger (hereinafter, referred to as “belt transfer charger”). 16) is turned on. In addition, the developing devices 21, 22 stopped at the developing position
When the colors 23 and 24 are different from the designated development color (eg, black), the revolver unit 20 is rotated after the developing bias is turned on, and the developing device 21 of the designated development color is moved to the developing position.

The intermediate transfer member 30 rotates to rotate the mark sensor 15
When 0 is detected as a reference mark, a scan start command for the first color (black) is transmitted. When the electrostatic latent image of the first color (black) on the photoconductor 10 is developed and the transfer to the intermediate transfer body 30 is completed, the revolver unit 20 is set so that the developing device 22 of the second color (for example, cyan) comes to the developing position. Rotate.
When the transfer to the intermediate transfer body 30 is completed, the cleaning unit 34 that has been in contact with the intermediate transfer body 30 until then is released so that the image on the intermediate transfer body 30 is not erased.
Then, when the reference mark detection interrupt of the mark sensor 150 is input again, the scan start command for the second color (cyan) is transmitted. As with the first color (black), the untransferred image is superimposed on the intermediate transfer body 30. After that, the revolver unit 20 is rotated so that the developing device 23 for the third color (magenta) is moved to the developing position. The third color (magenta) and the fourth color (yellow) are similarly developed and the image is superimposed on the intermediate transfer body 30.

On the other hand, when the image formation is started, the image forming apparatus feeds the transfer paper from the paper feed cassette. Then, a paper transfer charger (hereinafter, referred to as “paper transfer CH”) 3 for transferring the image on the intermediate transfer body 30 to the transfer paper 3
When the front end of the toner image on the intermediate transfer member 30 reaches 3 the registration of the transfer paper and the toner image is performed so that the front end of the transfer paper coincides with the front end of the toner image. In this way, when the transfer paper passes through the paper transfer CH33 which is superposed on the toner image on the intermediate transfer body 30 and connected to the positive potential power source, the transfer paper is charged with a positive charge by the corona discharge current,
The toner image is transferred. The charges charged on the transfer paper are discharged when passing through the position of a discharging core (not shown) provided at a stage slightly behind the paper transfer CH33. The transfer paper carrying the toner image is sent to the fixing unit 52 by the carrying belt 51. The fixing unit 52 heats and pressurizes the transfer paper to fix the toner image on the transfer paper.

When the transfer of the fourth color (yellow) is completed, the revolver prepares for repeat by rotating the revolver so that the developing device 21 of the first color (black) comes to the developing position. or,
At the same time, the cleaning unit 34 is also brought into the contact state from the released state to clean the transfer residual toner after the paper transfer on the intermediate transfer body 30 to prepare for the next image formation.

When the image forming apparatus transfers all the images onto the transfer paper, it shifts to the end sequence as shown in the signal chart of FIG. 7 and the flowchart of FIG. The image forming apparatus turns off the belt transfer CH16,
Transfer CH1 when the upper belt transfer CH16 is turned off
When the portion in contact with 6 reaches the position of the charging CH12, the charging CH12 is turned off (steps S1, S
2). Further, when the charging CH12 of the photoconductor 10 is turned off, the developing bias and the developing motor 112 are turned off when the portion in contact with the charging CH12 reaches the developing position (steps S3 and S4). From this point, the mark sensor 150 for detecting the alignment mark attached to the intermediate transfer body 30 is in a standby state for mark detection (step S5), and after the mark detection (step S6).
The drum motor 111 is turned on until the mark moves to the predetermined position, and the charge removal lamp 11 is turned off at the same time when the mark moves to the predetermined position and the drum motor 111 is turned off (steps S7 to S9).

In the image forming apparatus, after the image is transferred onto the transfer paper as described above, the charging CH 12 and the developing bias are adjusted according to the layout so as not to leave a history such that an abnormal image is left on the photoconductor 10. The intermediate transfer body 30 and the photoconductor 10 are rotated for a while in order to sequentially turn off.

When the next image forming start command is received during the end sequence, the relationship between the detection timing of the alignment mark attached to the intermediate transfer member 30 and the charged area on the photosensitive member 10 is determined. If the registration mark detection is always enabled without management, writing may start before the stable charged area is formed on the photoconductor 10 and uneven density may occur in the image of the first color.

Therefore, the printer control unit 100 stores the positional relationship between the position of the alignment mark during operation of the intermediate transfer member 30 and the mark sensor 150 for detecting the mark. The relative position detecting means 101a is used for alignment.
The relative position relationship between the moving position where the mark is moving and the position of the mark sensor 150 that detects the alignment mark is detected and stored in the RAM 103, and the mark detection time prediction means 101b uses the relative position at the start of image formation. Detection means 1
01a predicts a time until detecting the mark for positioning the relative positional relationship between the position of the mark sensor 150 for detecting the mark moving position and the mark for positioning detected, the time comparison means 101c mark detection The time until the alignment mark detected by the time predicting means 101b is compared with the time until the photosensitive member 10 is in a stable charged state, and the time until the alignment mark is detected is the photosensitive member. If the time is shorter than the time required for the photosensitive member 10 to stabilize, the mark detection signal from the mark sensor 150 is controlled not to be used as a reference for forming an image on the photosensitive member 10, and the photosensitive member 10 is exposed before the charge state becomes stable. It prevents the transfer of an image to the body 10. The operation in this case will be described with reference to the signal chart of FIG. 9 and the flowchart of FIG.

When a command to start the next image formation is received during the end sequence, the printer controller 100 causes the charging CH
Check whether 12 is on or off, and charge CH12
When is on, it is determined that the charged state of the photoconductor 10 is stable, and the subsequent mark detection signal is determined to be valid (steps S11 and S12). When the charging CH12 is off, the mark detection time predicting means 101b reads the position of the mark moving position for alignment stored in the RAM 103 by the relative position detecting means 101a from the RAM 103 and reads it.
Predicting time t ₁ required to detect the mark from the positional relationship between the mark sensor 150 for detecting a moving position and the mark of the mark for leaving the alignment (step S13).

Next, the time comparison means 101c reads the time t ₂ until the charged state of the photoconductor 10 is stored in advance from the RAM 103 or the ROM 102 (step S14), and the estimated time t ₁ until the mark is detected. Compared with the time t ₂ until the charged state of the photoconductor 10 stabilizes (step S15), the estimated time t ₁ until the mark is detected is the time t ₂ until the charged state of the photoconductor 10 stabilizes.
If longer is judged to enable subsequent mark detection signal (step S12), the time until the expected time t ₁ required to detect the mark is stabilized charging state of the photosensitive member 10 t ₂
If it is shorter, it is determined that the next mark detection signal should be invalid, and even if the mark detection signal is input, it is discarded. In order for the relative position detecting means 101a to detect the relative positional relationship between the mark moving position for position adjustment and the position of the mark sensor 150, for example, the RAM 103 or the ROM 10 is used.
In FIG. 2, the moving distance for one round of the positioning mark attached to the intermediate transfer body 10 is stored in advance, and the relative position detecting means 101a stores the moving distance for one round of the positioning mark stored in the RAM 103 or the ROM 102. match position from the mark sensor 150 detects the mark for alignment and
The relative position of the alignment mark and the mark sensor 150 is detected from the moving distance to the false mark moving position . From the movement distance of the alignment mark from the position where the mark sensor 150 detects the alignment mark to the alignment mark movement position , for example, the intermediate transfer member 30.
Alternatively, a counter such as an encoder may be provided to obtain from the count value of the encoder, or may be obtained by measuring the mark moving time with a timer.

Further, when the operation is suddenly stopped by opening the door, for example, during the termination sequence, it is unknown where the alignment mark is stopped. When the start command is received at the stop position, if the mark detection is always enabled, the image formation may start in the unstable state of the photoconductor 10 as in the case of receiving the start command in the end sequence. is there. Therefore, the relative position detecting means 101a detects and stores the relative positional relationship between the position of the mark for stopping the position when the intermediate transfer body 10 is stopped in an emergency and the position of the mark sensor 150 for detecting the mark for the position. The mark detection time predicting means 101b determines the position of the mark for alignment from the relative positional relationship between the position of the mark for stopping alignment detected by the relative position detecting means 101a at the start of image formation and the position of the mark sensor 150 for detecting the mark. Time comparison means 1 for predicting the time until detection of
Reference numeral 01c is the time until the mark for alignment, which is predicted by the mark detection time predicting means 101b, is detected and the photosensitive member 10
When the time until the alignment mark is detected is shorter than the time until the photoconductor 10 stabilizes, the mark sensor 150 is compared.
The mark detection signal from is not used as a reference for forming an image on the photoconductor 10 to prevent the image from being transferred to the photoconductor 10 before the charged state of the photoconductor 10 is stabilized. The image transfer timing is controlled in the same sequence as in the above case.

Further, based on the mark position predicting means 101a predicting the mark position during rotation of the intermediate transfer member, a mark for alignment and a mark sensor 15 for detecting the mark.
The distance between 0 and 0 may always be the same at the end of the normal sequence to make the time from the input of the image formation start instruction to the image output constant and to form a stable and good image. .

Further, the scanner exposure lamp 206 is turned on after the mark detection of the timing of the scanner exposure lamp 206 when a color superposed image is obtained, and the scanning scanning is started after the delay time t ₁ for the stable time has elapsed to start the image data. Was sent to the printer 1, but if the minimum required stabilization time is long, the time from mark detection to image writing on the photoconductor 10 will also be long, so in the image forming cycle of the first color It is necessary to further increase the number of turns of a certain intermediate transfer body 30. Therefore, as shown in FIG. 11, the mark detection time predicting means 101b is the relative position detecting means 101a.
Based on the relative positional relationship between the position of the mark sensor 150 and the position of the mark moving position or the mark stop position for position detection detected by the mark sensor, the time until the next mark for position alignment is detected and the reference position for forming an image. The time until the mark is detected for detection is estimated, and the time comparison unit 101c stabilizes the scanner exposure lamp 206 from the time until the mark for alignment, which is a reference for forming an image, predicted by the mark detection time prediction unit 101b is detected. The exposure of the scanner exposure lamp 206 is started before the minimum time t ₂ required for scanning, to secure the minimum time required for the scanner exposure lamp 206 to stabilize, and to detect the next mark. If it takes a long time for the scanner exposure lamp 206 to stabilize, the number of revolutions of the intermediate transfer member 30 should not be increased. I tried to stay.

In the above embodiment, the case of forming a color image has been described, but it may be applied to the case of forming a monochrome image.

[0040]

As described above, the present invention predicts the time until the alignment mark is detected from the relative positional relationship between the alignment mark movement position and the position of the mark sensor at the start of image formation. Then during the end sequence
When came start instruction of image formation, when the time to detect the mark for alignment predicted shorter than the time until the photoreceptor is stabilized, the image a mark detection signal from Ma Kusensa Since it is not used as a reference for the transfer to the photoconductor, it is possible to prevent the image from being transferred to the photoconductor before the charged state of the photoconductor is stabilized, and uneven color or the like occurs in the formed image. Can be prevented.

Further, when the intermediate transfer member is in an emergency stop, the time until the alignment mark is detected is predicted from the relative positional relationship between the alignment mark stop position and the position of the mark sensor at the start of image formation. And during the end sequence
The motion is suddenly stopped, and the image is displayed at that stop position.
When receiving the instruction of the start of image formation, when the time to detect the mark for alignment predicted shorter than the time until the photoreceptor is stabilized, a mark detection signal from Ma Kusensa image Since it is not used as a reference for the transfer to the photoconductor, it is possible to prevent the image from being transferred to the photoconductor before the charged state of the photoconductor is stabilized.

Further, after the positioning mark attached to the intermediate transfer member is moved for one round and the mark sensor detects the positioning mark, the positioning mark is detected .
Movement distance to the peak movement position, or until the intermediate transfer body is stopped.
Since the relative position of the alignment mark and the mark sensor is detected from the movement distance of the alignment mark in,
The relative position of the mark and the mark sensor can be easily detected.

Furthermore, since the distance between the alignment mark and the mark sensor for detecting the mark is always the same when the normal sequence ends, the time from the input of the image formation start instruction to the image output is fixed. In addition, it is possible to stably form a good image.

Furthermore, the mark moving position for alignment or
Predicts and predicts the time to detect the mark for alignment, which is the reference for forming an image, based on the relative positional relationship between the mark stop position when the intermediate transfer body stops in an emergency and the position of the mark sensor that detects the mark. The original is exposed in order to optically read the image of the original from the scanner from the time until the mark for alignment, which is the reference for forming the image, is detected .
Since the exposure timing of the exposure lamp is determined, the minimum time required for the exposure lamp of the scanner to stabilize can be secured, and an increase in the number of turns of the intermediate transfer member can be suppressed.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a basic configuration of an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a control block configuration of an embodiment of the present invention.

FIG. 3 is a configuration diagram of a printer control unit.

FIG. 4 is a connection diagram of an IO controller.

FIG. 5 is a configuration diagram of a driving portion of the printer.

FIG. 6 is a signal chart showing a normal image forming operation.

FIG. 7 is a signal chart showing a normal end sequence.

FIG. 8 is a flowchart for stopping the drum motor in a termination sequence.

FIG. 9 is a signal chart when an image formation instruction is received during the end sequence.

FIG. 10 is a flowchart when an image formation instruction is received during the end sequence.

FIG. 11 is a signal chart for controlling lighting of a scanner exposure lamp.

FIG. 12 is a signal chart for controlling lighting of a conventional scanner exposure lamp.

[Explanation of symbols]

1 printer 2 scanner 10 photoconductor 20 revolver unit 21-24 developing device 30 Intermediate transfer body 34 Cleaning Section 100 Printer control unit 101a Relative position detection means 101b Mark detection time prediction means 101c time comparison means 150 mark sensor 206 Scanner exposure lamp 800 System control unit

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-5-150574 (JP, A) JP-A-7-92763 (JP, A) JP-A-6-289684 (JP, A) JP-A-7- 281536 (JP, A) JP 63-253962 (JP, A) JP 61-233753 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 21/14 G03G 21 / 00 370-540 G03G 15/01-15/01 117 G03G 15/16-15/16 103

Claims (7)

(57) [Claims] 1. An image is formed on a photoconductor based on detection of a registration mark attached to the intermediate transfer member, the formed image is transferred to the intermediate transfer member, and transferred from the intermediate transfer member to a transfer paper. In the image forming apparatus, the relative position detecting means, the mark detecting time predicting means and the time comparing means are provided, and the relative position detecting means includes a mark moving position for alignment and a position of a mark sensor for detecting the mark for alignment. The relative positional relationship is detected and stored, and the mark detection time predicting means is a relative positional relationship between the position of the mark moving position for alignment detected by the relative position detecting means at the start of image formation and the position of the mark sensor for detecting the mark. Predict the time from when the alignment mark is detected until the start of the next image formation comes during the end sequence.
In this case, the time comparison means compares the time until the mark detection time prediction means detects the alignment mark predicted by the mark detection time prediction means with the time until the photosensitive member is in a stable charged state, If the time until the detection is shorter than the time until the photoreceptor is stabilized, the image forming apparatus characterized by not a reference for forming an image of the mark detection signal from Ma Kusensa the photoreceptor. 2. An image is formed on a photoconductor on the basis of detection of alignment marks attached to the intermediate transfer member, the formed image is transferred to the intermediate transfer member, and transferred from the intermediate transfer member to a transfer paper. The image forming apparatus includes a relative position detecting unit, a mark detecting time predicting unit, and a time comparing unit, and the relative position detecting unit is a mark for position alignment and a mark for position alignment when the intermediate transfer member is in an emergency stop. The mark detection time predicting means detects the relative positional relationship with the position of the mark sensor and stores the mark. The mark detection time predicting means detects the mark stop position for alignment detected by the relative position detecting means at the start of image formation and the mark detecting mark. This is the case when the time until the alignment mark is detected is predicted from the relative positional relationship with the sensor position, and the operation suddenly stops during the end sequence.
At that stop position, an image formation start command was received.
In this case, the time comparison means detects the position alignment mark by comparing the time until the mark detection time prediction means detects the position alignment mark and the time until the photosensitive member is in a stable charged state. If the time to is shorter than the time until the photoreceptor is stabilized, the image forming apparatus characterized by not a reference for forming an image of the mark detection signal from Ma Kusensa the photoreceptor. 3. The relative position detecting means for the position adjustment based on the moving distance of one round of the position adjusting mark and the moving distance from the position where the mark sensor detects the position adjusting mark to the position for the position adjusting mark movement. The image forming apparatus according to claim 1, wherein a relative position between the mark and the mark sensor is detected. 4. The relative position detecting means moves a distance for one round of the positioning mark and the moving distance of the positioning mark from when the mark sensor detects the positioning mark to when the intermediate transfer member is stopped. The image forming apparatus according to claim 2, wherein the relative position between the alignment mark and the mark sensor is detected from the position. 5. The image forming apparatus according to claim 1, wherein the relative positional relationship between the alignment mark and the mark sensor for detecting the mark is always the same when the end sequence is normally completed. 6. A scanner having a scanner for optically reading an image of an original by exposing the original with an exposure lamp, and the mark detection time predicting means detects the mark moving position for alignment and the mark detected by the relative position detecting means. The time comparison means predicts the time until the next alignment mark is detected from the relative positional relationship with the position of the mark sensor to be detected, and the time until the alignment mark that serves as a reference for forming an image is detected. 2. The exposure timing of the exposure lamp of the scanner is determined from the time until the mark for alignment, which is a reference for forming an image, predicted by the mark detection time prediction means is detected.
The image forming apparatus described. 7. A scanner is provided which optically reads an image of an original by exposing the original with an exposure lamp, and the mark detection time predicting means detects the mark stop position for alignment and the mark detected by the relative position detecting means. The time comparison means predicts the time until the next alignment mark is detected from the relative positional relationship with the position of the mark sensor to be detected, and the time until the alignment mark that serves as a reference for forming an image is detected. The exposure timing of the exposure lamp of the scanner is determined from the time until the mark for alignment, which serves as a reference for forming an image, predicted by the mark detection time predicting means is detected.
The image forming apparatus described.