JP2000159395A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To invariably provide a good image with no image tip positional drift by providing a control means correcting the drive start time of a registration roller to align a sheet and the tip position of a toner image. SOLUTION: When a counter reaches 3000 sheets or above (step 121), the process goes to the next step for a drift correction action, it is confirmed that five or more sheets of A4 size exist (steps 122, 123), then the process goes to the next step. The corrected conveyance time is calculated (step 127), the drift of the drive timing of a registration roller is calculated (step 127), the timing of spring clutch-on is obtained then the counter is cleared (step 130), and the correcting action of the drive timing of the registration roller is completed. Each time the counter reaches 3000 sheets of copies or above thereafter, these steps are repeated to automatically correct the drive timing of the registration roller, and a position correction is automatically made for a toner image on a photoreceptor and the tip of the sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an image forming apparatus for correcting the driving of a registration roller for supplying a sheet in synchronization with the leading end of a toner image on a photosensitive member in an electrophotographic apparatus or the like.

[0002]

2. Description of the Related Art In an image forming apparatus such as an electrophotographic apparatus, in order to synchronize the leading end position of a sheet and the position of a toner image on a photoreceptor at the time of transfer, a sheet supplied from a sheet cassette or the like is kept stationary. After being once stopped by the registration roller and the leading ends thereof are aligned, the driving of the registration roller is started in accordance with the toner image on the photosensitive member, and the sheet is conveyed in the direction of the transfer position.
The registration roller is connected to and driven by a main motor via a clutch or the like.During the repetition of the copying operation, the clutch is deviated in drive timing due to deterioration of the clutch or contamination in the machine, and thus the driving of the registration roller. The positional deviation between the toner image and the leading edge of the sheet has occurred due to the timing shift.

For example, as shown in FIG. 7, when a connection between a shaft 1 driven by a main motor and a registration roller 2 is made via a general-purpose electromagnetic spring clutch 3, a current flows through a coil by an electric signal during drive transmission. The spring 4 winds around the drive shaft 5 which is the shaft of the registration roller 2, and the drive shaft 5 and the registration roller 2 start moving when the winding is completed. Accordingly, the drive shaft 5 is gradually scraped off by the spring 4 while the electromagnetic spring clutch 3 is used, so that the time required for the connection of the drive by the electromagnetic spring clutch 3 is gradually delayed as shown in FIG. It is generally known that this phenomenon occurs. Therefore, the electromagnetic spring clutch 3 in which the time required for connection is gradually delayed is
Actually, the main motor and the registration roller 2 of the image forming apparatus
When this is used as a connection means, the paper conveyance start timing is delayed and this is one of the factors that cause the image leading edge position shift.

Conventionally, in order to correct the displacement of the leading edge of the image, a service technician visually confirms the formed image at the time of the periodic inspection to recognize the presence or absence of the leading edge of the image.
When the image tip position is shifted, the apparatus main body is set to the correction mode by changing the correction code, and the driving timing of the registration roller is manually corrected while forming the image and checking the image.

[0005]

Conventionally, when an image tip position shift occurs, a service engineer manually corrects the drive timing of the registration rollers while checking the formed image visually during a periodic inspection.

For this reason, the time required for the maintenance at the time of the periodic inspection is long, and the efficiency of the maintenance is reduced. On the other hand, the inside of the apparatus varies depending on the use environment of the image forming apparatus. Before the inspection, there is a case where the image tip position shift is remarkable, and in that case, it is necessary to call a service person and request maintenance for correcting the tip position shift. In addition, the period of the periodic inspection has tended to be longer in recent years, and a problem has arisen that the frequency of maintenance requests other than the periodic inspection due to the displacement of the image leading edge position increases.

Accordingly, the present invention has been made to solve the above-mentioned problems, and automatically corrects the shift of the driving timing of the registration roller to always obtain a good image free from the image tip position shift. An object is to provide an excellent image forming apparatus.

[0008]

According to the present invention, as a first means for solving the above-mentioned problems, an apparatus main body having an image forming means for forming a toner image on an image carrier, and a sheet provided on the apparatus main body are provided. A supply unit, a sheet transport path extending from the sheet supply unit via the image carrier of the image forming unit to a sheet discharge unit, and a paper supply path provided between the sheet supply unit and the image carrier in the sheet transport path. A registration roller for transporting the paper supplied from the paper supply means in synchronization with the toner image on the image carrier; a driving means for driving the registration roller; The corrected transport time of the paper is compared with the reference transport time of the paper passing through the paper transport path at the time of initializing, and the drive start time of the registration roller by the driving means is corrected to thereby correct the paper and the toe. - in which provision and control means for aligning the leading end position of the image.

According to the present invention, as a second means for solving the above-mentioned problems, an apparatus main body having an image forming means for forming a toner image on an image carrier, a paper supply means provided in the apparatus main body, A sheet conveying path extending from the sheet supplying unit to the sheet discharge unit via the image carrier of the image forming unit; and the sheet supplying unit provided between the sheet supplying unit and the image carrier in the sheet conveying path. Roller for transporting the paper supplied from the image carrier in synchronization with the toner image on the image carrier, driving means for driving the registration roller, and correction transport of the paper passing through the paper transport path during correction The driving start time of the registration roller by the driving means is corrected so that the time coincides with the reference conveyance time of the paper passing through the paper conveyance path at the time of initializing, and the paper and the toner image are corrected. It is intended to provide a control means for aligning the tip position.

[0010] The present invention also provides a third aspect for solving the above problems.
Means, an apparatus main body having an image forming means for forming a toner image on an image carrier, a paper supply means provided in the apparatus main body, and a paper discharge from the paper supply means via the image carrier of the image forming means. And a sheet provided from the sheet supply means in the sheet conveyance path and reaching the image carrier, and synchronized with the toner image on the image carrier. A registration roller for transporting the registration roller, a driving unit for driving the registration roller,
After calculating the difference between the corrected transport time of the paper passing through the paper transport path at the time of correction and the reference transport time of the paper passing through the paper transport path at the initial time, the calculated difference is calculated by the driving means. There is provided control means for correcting the driving start time of the roller to align the leading end positions of the sheet and the toner image.

According to a fourth aspect of the present invention, there is provided an apparatus body having image forming means for forming a toner image on an image carrier, a sheet supply means provided in the apparatus body, and A sheet transport path extending from the sheet supply unit to the paper discharge unit via the image carrier of the image forming unit; and a paper supply path provided between the sheet supply unit and the image carrier in the sheet transport path. A registration roller that conveys the supplied paper in synchronization with the toner image on the image carrier, a driving unit that drives the registration roller, and two points that sandwich the registration roller in the paper conveyance path during correction After calculating the difference between the corrected transport time of the paper passing through the gap and the reference transport time of the paper passing between two points sandwiching the registration roller at the initial time, the calculated difference That the registration roller drive start time correction to the paper and the toner - is intended to provide a control means for aligning the leading end position of the image.

According to a fifth aspect of the present invention, there is provided an apparatus body having image forming means for forming a toner image on an image carrier, a sheet supply means provided in the apparatus body, and A sheet conveying path extending from the sheet supplying unit to the sheet discharge unit via the image carrier of the image forming unit; and the sheet supplying unit provided between the sheet supplying unit and the image carrier in the sheet conveying path. Roller for transporting the paper supplied from the image carrier in synchronization with the toner image on the image carrier, driving means for driving the registration roller, and upstream of the registration roller in the paper transport path. A first sensor and a second sensor provided downstream of the registration roller in the paper transport path, and detecting a transport time of the paper passing between the first sensor and the second sensor; Detecting means, a storage means for storing a reference transport time of the sheet detected by the detecting means at the time of initializing, and a corrected transport time of the sheet detected by the detecting means at the time of correction and stored in the storage means. After calculating the difference from the reference transport time, the calculated length is provided with control means for correcting the drive start time of the registration roller by the drive means to align the leading end positions of the paper and the toner image. It is.

According to the present invention, the control means drives the registration roller by comparing the transport time of the paper passing through the paper transport path with the reference transport time of the paper passing through the paper transport path at the time of initializing. Correcting the start time eliminates the need for a serviceman to manually perform the image tip position correction operation during maintenance, thereby reducing maintenance.In addition, the tip position shift of the image can be reduced according to the need for deterioration of the clutch or use environment. It can be automatically corrected and always obtains a high-quality image with the tip position corrected properly.
This eliminates the need for serviceman calls and improves serviceability and reliability.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in FIGS. FIG. 1 shows the internal configuration of the entire electrophotographic apparatus. An image forming unit 11 for performing charging, exposure, development, transfer, peeling, cleaning, charge removal, fixing, and the like is built in an apparatus main body 10. An automatic double-sided device 12 having a reversing guide 12a and a transport roller 12b is provided at a lower part of the sheet feeding device. 13 is mounted. On the right side of the apparatus main body 10, a paper feed tray 14 for supplying paper P to the apparatus main body 10 by hand is provided.

On the other hand, a drum-shaped photoreceptor 20 as an image carrier is disposed substantially at the center of the apparatus main body 10, and a charging charger is provided around the photoreceptor 20 along the rotation direction thereof.
A charger 21, an LED erasing array 22, an exposure unit 23a of an exposure device 23, a developing device 24, a transfer charger 25, a peeling charger 26, a cleaning device 27, and a charge removing device 28 are sequentially arranged. The exposure device 23 converts the original placed on the original placing table 7 provided on the upper surface of the apparatus main body 10 into a reflector 5.
The light image reflected from the original is illuminated by an exposure lamp 51 surrounded by a reference numeral 0 and guided to a lens 55 through first to third mirrors 52 to 54 in sequence, and then the light image transmitted through the lens 55 is converted to a light image. , And the fourth to seventh mirrors 56 to 59 are sequentially guided to the photoconductor 20. Reference numeral 48 denotes moving means for scanning and moving the exposure lamp 51, the mirrors 52 to 54, 56 to 58, and the lens 55.

Further, in the apparatus main body 10, the paper supplied from the paper supply cassette device 13 or the paper supply tray 14 is transferred to the apparatus main body 1 via a transfer position facing the photosensitive member 20.
Paper transport path 3 leading to a paper discharge tray 8 provided on the left side of
1 is formed.

A pair of registration rollers 32 and an automatic duplexer 1 are provided upstream of the photoconductor 20 in the paper transport path 31.
2, paper P from the paper cassette unit 13 and the paper tray 14
First to third pickup rollers 41a to 41
41c, first to third separation rollers 42a to 42c, first and second conveyance rollers 43a and 43b are provided, and a conveyance belt 47, a fixing device 33, and a conveyance roller 3 are provided on the downstream side.
4, a gate 35 and a paper discharge roller pair 36 are arranged.
Further, a registration sensor 37 for detecting passage of the sheet P and an exit (hereinafter, referred to as EXIT) are provided upstream of the registration roller 32 and downstream of the conveyance roller 34 in the sheet conveyance path 31.
The microcomputer 62, which is provided with a sensor 38, calculates an average value of the time from when the rear end of the first sheet P passes through the registration sensor 37 to when the fifth sheet P passes through the EXIT sensor 38. And the paper transport time.

The shaft 32a of the registration roller 32
Is connected via a gear or a belt (not shown) to a drive shaft 60a driven by a main motor 60 as drive means, and via an electromagnetic spring clutch 61 as connection means. It is designed such that the drive is transmitted from the drive shaft 60a to the shaft 32a and the registration roller 32 by the connection operation.

FIG. 3 shows a control system 7 of the registration roller 32.
FIG. The microcomputer 62, which controls the entire apparatus main body 10 and controls the driving of the electromagnetic spring clutch 61 of the registration roller 32 and also serves as control means for correcting the drive control, includes various switches for controlling the apparatus main body 10. Sensors (not shown) or a control panel 66 and the like are connected, and a registration sensor 37 and an EXIT sensor 38 are connected via resistors 40a to 40d to detect the passage of the paper P and measure the transport time. It consists of The microcomputer 62 has a ROM (Read Only Memory) 67 for storing a program for controlling the apparatus main body 10 and various switches and sensors, and data and images from the resist sensor 37, the EXIT sensor 38, and the like. A RAM (random access memory) 68 for storing formation conditions and the like is connected. Further, a driver IC 71 for controlling the current of the electromagnetic spring clutch 61 is connected to the microcomputer 62.

Next, the operation will be described. When adjusting the driving timing of the registration roller 32 to adjust the image leading end position during the shipping inspection of the normal apparatus main body 10, A4
(Or LT) size paper P is passed five sheets, a normal copying operation is performed, and if the deviation between the toner image and the leading end position of the paper P is within the specification of all five sheets, the adjustment is completed, and other adjustment steps are performed. Proceed to.

Here, in a normal copying operation, the image forming means 11 sequentially performs the steps of charging, exposing, and developing the photoreceptor 20 to form a toner image on the photoreceptor 20 while feeding the paper P. The sheet is conveyed from the cassette device 13 or the sheet feed tray 14 to the registration roller 32, temporarily stopped at the position of the registration roller 32, and then conveyed to the transfer position in synchronization with the toner image on the photoconductor 20. After the toner image is transferred at the transfer position, the sheet P is peeled off from the photoreceptor 20, the toner image is fixed via the transport belt 47 and the fixing device 33, and discharged in the direction of the discharge tray 8 to complete the manual copying operation. I do. still,
After the transfer is completed, the photosensitive member 20 is cleaned by the cleaning device 27 and the static elimination device 28.
After that, the next copy is made possible.

Using the tip position adjustment process at the time of shipping inspection for performing such a copy operation, a reference transport time (hereinafter referred to as (data A)) used for correcting the drive timing of the registration roller 32 described later is set. I do. That is,
At the time of completing the leading edge position adjustment process at the time of shipping inspection using A4 (or LT) size paper P, which is frequently used,
The time when the rear end of the first sheet P passing through the sheet transport path 31 passes through the registration sensor 37 is defined as 0 (zero).
The sheet conveyance time until the rear end of the fifth sheet P passes through the EXIT sensor 38 is measured, and the average value when the fifth sheet P is passed is stored in the RAM 68 as (data A).

More specifically, as shown in the flowcharts of FIGS. 4 and 5, in the adjustment mode at the time of shipping inspection, various necessary adjustment codes are input from the control panel 66, and in step 100, the tip position adjustment mode is set. After confirming the adjustment code AJ = 1 to be performed, an adjustment value is set in step 101. If the mode is not the tip position adjustment mode in step 100, the process proceeds to another adjustment mode. Step 10
If the adjustment value set has been set in step 2, step 10
Proceed to 3 to execute the tip position confirmation mode.

In the tip position confirmation mode, the number of set is 5, A4
(Or LT) size paper P, step 10
At step 6, five sheets of A4 (or LT) size paper P are set in the sheet cassette 13 and at step 107 the print key is turned on from the control panel 66 to start copying, and the routine proceeds to step. If it is confirmed in step 108 that the copy key is turned on, the flow advances to step 110 to perform a calculation set of (data A), which is the transport time of the sheet P at the time of the initial operation, while performing the same operation as in the normal copying. In other words, during the same operation as the continuous copying of five sheets of paper at the time of initializing, the time when the rear end of the first sheet P has passed the registration sensor 37 is set to 0 (zero), and the rear end of the fifth sheet P is set. Measured the transport time of the paper P until the paper passed the EXIT sensor 38, and measured the five papers P
Is divided by the set number = 5, an average value of the transfer time is calculated, and this is set as a reference transfer time (data A).
In (1), (data A) is stored in the RAM 68, and the operation of the front end position confirmation mode is completed. Then, the flow returns to step 100 to perform other adjustment modes required at the time of shipping inspection.

After that, the apparatus main body 10 is installed on the user side. If the average value of the paper transport time at the time of the initial is changed by a serviceman's adjustment at the time of installation or the like, the changed value is used as the reference transport time. It is determined that there is (data A), and is replaced with (data A) stored in the RAM 68 at the time of shipping inspection.

Next, a description will be given of a tip position correcting operation for correcting a deviation of the drive timing of the registration roller 32 that occurs during the actual copying operation. The tip position correction operation during the copy operation is performed every 3000 sheets or more by counting up a counter (not shown) provided in the apparatus main body 10. That is, at the time of correction, A4 (or L
T) Assuming that the corrected transport time, which is the average value of the transport times when five sheets P of the size P are passed, is (Data B), the registration roller 32 calculated from {(Data B)-(Data A)} The driver IC 71 is controlled by the microcomputer 62 so as to accelerate the timing of turning on the shift length electromagnetic spring clutch 61.

More specifically, as shown in the flow chart of FIG. 6, while the copy operation is being performed in the ready state, it is confirmed in step 120 that the print key has been turned on. If the number is 3000 or more, the process proceeds to step 122 for a shift correction operation. At step 122, it is determined whether or not the user has set at least five sheets of paper P, and if it is five or more, it is determined at step 123 whether or not the paper P is A4 (or LT) size. , A4 (or LT) size, step 124
Proceed to. If the counter is not 3,000 or more in step 121, if the number of sheets P is not five or more in step 122, the sheet P is A4 (or L) in step 123.
T) If it is not the size, the process proceeds to step 126 to perform a normal copy operation, and after the copy is completed, it becomes ready and waits for the next copy.

In step 124, a calculation set of (data B), which is the correction transport time during the copying operation at the time of correction, is performed. That is, the reference transport time (data A)
During the continuous copying of five sheets of paper in the same manner as in the above, the time when the rear end of the first sheet P has passed the registration sensor 37 is set to 0 (zero), and the rear end of the fifth sheet p Measures the paper transport time up to the point when the EXIT sensor 38 is depressed, and sets the measured paper transport time for five sheets to the number =
Divide by 5 to calculate the average value of the transport time, use this as the corrected transport time (data B), and proceed to step 127. In step 127, the deviation of the drive timing of the registration roller 32 ((data B)-(data A)) = C is calculated, and in step 128, {(on timing of the electromagnetic spring clutch 61) -C} = (electromagnetic spring clutch) 61, the microcomputer 6
After the driver IC 71 (ON timing of the electromagnetic spring clutch 61) has been shortened by C, the counter is cleared in step 130, all the operation of correcting the drive timing of the registration roller 32 is completed, and the ready state is set to the next copy. To wait. After this, 3000 copies
Steps 120 to 130 each time the number of sheets reaches
Is repeated to automatically correct the drive timing of the registration roller 32, and the toner image on the photoconductor 20 and the leading end position of the paper P are automatically corrected.

With this configuration, the paper P can be used in the leading end position adjustment process at the time of initial inspection, such as during shipping inspection or installation.
After the reference transport time (data A) is calculated and stored in the RAM 68, the corrected transport time (data B) of the paper P is calculated at the time of the leading edge position correction for every 3000 copies or more, and (data A) and (data The drive timing of the electromagnetic spring clutch 61 is advanced by the microcomputer 62 by the length of the difference B), so that the shift of the drive timing of the registration roller 32 can be automatically corrected without waiting for maintenance by a serviceman as in the related art. It is possible to correct the displacement of the leading end position of the image at every predetermined copy cycle, so that a good image can always be obtained. Accordingly, there is no need for a maintenance request for tip position correction, so that serviceability is improved, and at the time of periodic inspection, a correction operation of the drive timing of the registration roller can be omitted, thereby improving maintainability.

In this embodiment, the transport time of the paper P is calculated by detecting the time during which the paper P passes through almost the entire section of the paper transport path 31 from the registration sensor 37 to the EXIT sensor 38. Therefore, not only the deviation of the driving timing of the registration roller 32 but also the overall deviation of the paper conveyance occurring in the entire paper conveyance path 31 such as the fixing device 33 can be corrected by the driving timing of the registration roller 32.

The present invention is not limited to the above-described embodiment, and can be changed without departing from the spirit of the present invention. For example, the connection means for transmitting the drive of the drive means to the registration roller is electromagnetically connected. It is not limited to a spring clutch. The position of the sensor for detecting the paper transport time is arbitrary as long as it can detect the drive timing of the registration roller, and the number of sheets required for calculating the average transport time of the paper is not limited. The cycle of performing the tip position correction is also optional as needed.

[0032]

As described above, according to the present invention, the deviation of the driving timing of the registration rollers can be automatically corrected and controlled every predetermined copy cycle, and the deviation of the image leading edge position can be easily adjusted at the required timing. And it is possible to always obtain a good image with no image tip position shift. Since the drive timing of the registration rollers is automatically corrected, there is no need for maintenance requests for correction of the drive timing, and there is no need for a serviceman to correct the drive timing of the registration rollers at the time of periodic inspection. Serviceability and maintainability can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating an apparatus main body according to an embodiment of the present invention.

FIG. 2 is a partial perspective view showing a registration roller according to the embodiment of the present invention.

FIG. 3 is a block diagram illustrating control of an electromagnetic spring clutch according to the embodiment of the present invention.

FIG. 4 is a flowchart illustrating an adjustment mode during shipping inspection according to the embodiment of the present invention.

FIG. 5 is a subroutine showing a tip position confirmation mode in the flowchart of the adjustment mode at the time of shipping inspection shown in FIG. 4 of the embodiment of the present invention.

FIG. 6 is a flowchart illustrating a correction operation of driving timing of a registration roller according to the embodiment of the present invention.

FIG. 7 is a partial perspective view showing a registration roller using a conventional electromagnetic spring clutch.

FIG. 8 is a graph showing the deterioration characteristics of a conventional electromagnetic spring clutch.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Device main body 11 ... Image forming means 13 ... Paper feed cassette device 20 ... Photoreceptor 25 ... Transfer charger 31 ... Paper conveyance path 32 ... Registration roller 33 ... Fixing device 37 ... Registration sensor 38 ... EXIT sensor 60 ... Main motor 61 ... Electromagnetic spring clutch 62 ... Microcomputer 66 ... Control panel 67 ... ROM 68 ... RAM 70 ... Control system 71 ... Driver IC

Claims (9)

[Claims] An apparatus main body having an image forming means for forming a toner image on an image carrier; a paper supply means provided in the apparatus main body; and a discharge means from the paper supply means via the image carrier of the image forming means. A sheet transport path reaching a paper section, and a sheet provided from the sheet supply means in the sheet transport path and reaching the image carrier is supplied from the sheet supply means to a toner image on the image carrier. A registration roller that conveys in synchronization, driving means for driving the registration roller,
Compensating the corrected transport time of the paper passing through the paper transport path at the time of correction with the reference transport time of the paper passing through the paper transport path at the initial time, and correcting the drive start time of the registration roller by the driving unit. An image forming apparatus comprising: control means for aligning the leading end positions of the sheet and the toner image. 2. An apparatus main body having an image forming means for forming a toner image on an image carrier, a paper supply means provided in the apparatus main body, and a discharge from the paper supply means via the image carrier of the image forming means. A sheet transport path reaching a paper section, and a sheet provided from the sheet supply means in the sheet transport path and reaching the image carrier is supplied from the sheet supply means to a toner image on the image carrier. A registration roller that conveys in synchronization, driving means for driving the registration roller,
The correction start time of the registration roller by the driving unit is corrected so that the corrected conveyance time of the paper passing through the paper conveyance path at the time of the correction coincides with the reference conveyance time of the paper passing through the paper conveyance path at the initial time. And a control unit for aligning the leading end positions of the paper and the toner image. 3. An apparatus body having an image forming means for forming a toner image on an image carrier, a sheet supply means provided in the apparatus body, and discharging from the sheet supply means via the image carrier of the image forming means. A sheet transport path reaching a paper section, and a sheet provided from the sheet supply means in the sheet transport path and reaching the image carrier is supplied from the sheet supply means to a toner image on the image carrier. A registration roller that conveys in synchronization, driving means for driving the registration roller,
After calculating the difference between the corrected transport time of the paper passing through the paper transport path at the time of correction and the reference transport time of the paper passing through the paper transport path at the initial time, the calculated difference is calculated by the driving means. An image forming apparatus comprising: a control unit configured to correct a driving start time of a roller to align a leading end position of the sheet and the leading end of the toner image. 4. An apparatus main body having an image forming means for forming a toner image on an image carrier, a paper supply means provided in the apparatus main body, and discharging from the paper supply means via the image carrier of the image forming means. A sheet transport path reaching a paper section, and a sheet provided from the sheet supply means in the sheet transport path and reaching the image carrier is supplied from the sheet supply means to a toner image on the image carrier. A registration roller that conveys the sheet synchronously, a driving means for driving the registration roller, and a correction conveyance time for the sheet passing between two points sandwiching the registration roller in the sheet conveyance path at the time of correction and the registration at the time of initialization. After calculating the difference from the reference transport time of the paper passing between two points sandwiching the roller, the calculated difference length corrects the driving start time of the registration roller by the driving means, and corrects the use time. And the toner - image forming apparatus characterized by comprising a control means for aligning the leading end position of the image, a. 5. An apparatus body having an image forming means for forming a toner image on an image carrier, a sheet supply means provided in the apparatus body, and discharging from the sheet supply means via the image carrier of the image forming means. A sheet transport path reaching a paper section, and a sheet provided from the sheet supply means in the sheet transport path and reaching the image carrier is supplied from the sheet supply means to a toner image on the image carrier. A registration roller that conveys in synchronization, a driving unit that drives the registration roller, a first sensor provided upstream of the registration roller in the paper conveyance path, and a downstream of the registration roller in the paper conveyance path. A second sensor provided in the first
Detecting means for detecting a transport time of the paper passing between the first sensor and the second sensor; storing means for storing a reference transport time of the paper detected by the detecting means at initial time; After calculating the difference between the corrected transport time of the paper detected by the means and the reference transport time stored in the storage means, the calculated difference length corrects the drive start time of the registration roller by the drive means. And a control unit for aligning the leading end positions of the paper and the toner image. 6. An apparatus body having an image forming means for forming a toner image on an image carrier, a sheet supply means provided in the apparatus body, and discharging from the sheet supply means via the image carrier of the image forming means. A sheet transport path reaching a paper section, and a sheet provided from the sheet supply means in the sheet transport path and reaching the image carrier is supplied from the sheet supply means to a toner image on the image carrier. A registration roller that conveys in synchronization, a driving unit that drives the registration roller, a first sensor provided upstream of the registration roller in the paper conveyance path, and a downstream of the registration roller in the paper conveyance path. A second sensor provided in the first
Detecting means for detecting a transport time of a predetermined number of sheets continuously passing between the sensor and the second sensor;
Storage means for storing a reference transport time of the paper obtained by the detection means at the time of initializing; and a correction transport time of the paper obtained by the detection means at the time of correction and the reference transport time stored in the storage means. Control means for correcting the driving start time of the registration roller by the driving means after calculating the difference, and aligning the leading end of the toner image with the sheet. Forming equipment. 7. The apparatus according to claim 1, wherein the control unit automatically corrects the driving start time of the registration roller for each predetermined number of image formation sheets.
The image forming apparatus according to any one of the above. 8. The image forming apparatus according to claim 1, wherein the driving unit includes a connection unit that controls driving or stopping of the registration roller. 9. The image forming apparatus according to claim 8, wherein the connecting means is an electromagnetic spring clutch.