JP2000128386A - Sheet carrying device and image forming device furnished with sheet carrying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a specified interval when the interval of sheets is narrowed on a sheet carrying device. SOLUTION: A sheet carrying device is furnished with sheet feeding means 372, 373 to feed sheets from a sheet loading means 36 on which the sheets are loaded, a first sheet carrying means 374, a second sheet carrying means 378, and a third sheet carrying means 377 arranged in sequence toward the downstream in the feeding direction of the sheets from the sheet loading means and to carry the sheets, a sheet interval judging means 379 to judge whether the interval of the sheets is a specified interval or not by detecting passing of the sheets between the second sheet carrying means and the third sheet carrying means and a control means to control at least the first sheet carrying means and the second sheet carrying means out of the sheet feeding means and the first sheet carrying means and the second carrying means so as to carry the sheets with the specified interval in accordance with judgement of the sheet interval judgement means.

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 such as an electrophotographic copying machine, an analog copying machine, a color copying machine, a printer, and a page printer.

[0002]

2. Description of the Related Art Conventionally, when an image is formed at a high speed in, for example, an electrophotographic image forming apparatus, the image forming speed is controlled by the image forming process in addition to the feeding and conveyance of the transfer paper sheet. That is, a series of operations of latent image formation, development, transfer of a toner image to a transfer sheet, and fixing are performed at high speed. For example, in order to realize an image forming apparatus capable of forming 60 images per minute for an image forming apparatus capable of forming 30 images per minute, it is necessary to feed and transport the transfer paper. In addition, the driving speed required for the image forming process is set to double.

[0003]

However, in the above-described conventional example, in order to realize high-speed image formation, it is required to speed up the image forming process in addition to the transfer of the transfer paper. Was needed.

This means that, for example, in forming a latent image in an image forming process, in a digital image forming apparatus, it is necessary to operate the image processing means and a latent image forming means such as a laser at a high speed. When developing an image forming apparatus capable of forming 60 images per minute for an image forming apparatus capable of forming an image of the same type, the image processing unit or the like having the image clock frequency doubled is required. It had been.

In the analog image forming apparatus, it is necessary to double the driving speed of a document scanner for scanning a document to be copied.

Further, in both cases, an image forming process such as development and transfer of a toner image is, so to speak, the most important technique in an electrophotographic image forming apparatus, and it takes a long time to determine its configuration and method. Consideration time was required, and development of an image forming apparatus accompanying high-speed image formation required a great deal of resources.

(Purpose) The present invention is directed to a sheet conveying apparatus capable of setting a normal interval when a sheet interval becomes narrow, and an image forming apparatus provided with the apparatus without changing the image forming process speed. It is an object of the present invention to provide an image forming apparatus having a high image forming efficiency and a high productivity by making the interval between sheets fed to a copy section substantially constant.

[0008]

According to a first aspect of the present invention, there is provided a sheet conveying apparatus for feeding a sheet from a sheet stacking unit on which sheets are stacked, and feeding the sheet from the sheet stacking unit. A first sheet conveying unit, a second sheet conveying unit, and a third sheet conveying unit that are arranged in order in the downstream of the direction to convey the sheet, and between the second sheet conveying unit and the third sheet conveying unit. Detecting the passage of the sheet and determining whether or not the interval between the sheets is a predetermined interval; and conveying the sheet at a predetermined interval based on the determination by the sheet interval determining unit. Control means for controlling at least the first sheet conveying means and the second sheet conveying means among the sheet feeding means, the first sheet conveying means and the second sheet conveying means. To have.

In the first sheet conveying apparatus of the present invention, the sheet is fed from the sheet stacking means by the sheet feeding means, and the sheet is conveyed by the first, second and third sheet conveying means. I have.

At this time, the sheet interval judging means detects the sheet interval and judges whether or not it is a predetermined interval. Based on this judgment, the control means controls at least the first and second sheet conveying means. Thus, when the interval between the sheets is narrow, the sheet can be fed at a predetermined interval.

According to a second sheet conveying apparatus of the present invention, the control means starts the third sheet conveying means to start conveying the previous sheet, and then determines the next conveyed sheet by the sheet interval judging means. Based on the time it takes to detect
The conveyance control of the next conveyed sheet is performed.

In a third sheet conveying apparatus according to the present invention, the control means drives the third sheet conveying means, and after the conveyance of the previous sheet is completed, the next sheet conveyed by the sheet interval judging means. The conveyance control of the next conveyed sheet is performed based on the time until the detection.

According to a fourth aspect of the present invention, in the above-mentioned sheet conveying apparatus, the control means determines a time based on a time from when the preceding sheet is detected by the sheet detecting means to when the next sheet to be conveyed is detected. The conveyance control of the next conveyed sheet is performed.

In a fifth sheet conveying apparatus according to the present invention, the sheet interval determining means determines that a delay occurs when the sheet interval is longer than a predetermined interval, and determines that the sheet interval is longer than the predetermined interval. When it is short, it is determined to arrive early.

In a sixth sheet conveying apparatus according to the present invention, when the control means determines that the distance between the previous sheet and the next sheet is small,
The second sheet conveying means is stopped, the interval between the next sheet and the previous sheet is set to a predetermined interval, and the next sheet is conveyed for a time corresponding to the time delayed for the next sheet. The interval between the next sheet and the further next sheet is delayed to the predetermined interval.

According to a seventh sheet conveying apparatus of the present invention, when the distance between the previous sheet and the next sheet is narrow,
The second sheet conveying means is stopped, the interval between the next sheet and the previous sheet is set to a predetermined interval, and when the next sheet is conveyed, the sheet feeding means and the second sheet conveying are controlled. The starting with the means is delayed by a predetermined time.

According to an eighth aspect of the present invention, when the control means determines that the distance between the previous sheet and the next sheet is small,
Stopping the second sheet conveying means for a predetermined time, and delaying the start of the sheet feeding means and the second sheet conveying means for a predetermined time when controlling the conveyance of the next sheet. It has become.

According to a ninth sheet conveying apparatus of the present invention, the first
The sheet conveying means and the third conveying means have registration rollers.

An image forming apparatus according to the present invention includes any one of the first to ninth sheet conveying devices and an image forming means for forming an image on a sheet sent by the sheet conveying device. Have.

Since the image forming apparatus of the present invention includes a sheet conveying device capable of conveying a sheet at a predetermined interval, the image forming process can be performed at a high speed without changing the image processing speed.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an image forming apparatus 1 according to the present invention.
1 shows a schematic cross-sectional front view of a digital copying machine as an example.

The sheet includes paper, a thin sheet as a substitute for paper, and the like. In the copying machine of the present embodiment, the sheet on which an image is formed is referred to as a "document" and the sheet on which the image is formed is referred to as a "transfer". Paper ".

The digital copying machine 10 has a reader unit 1
The printer unit 2 is provided on the lower part.

The reader unit 1 includes a document table 1 on which a document is placed.
1, a document pressure plate 12 for pressing a document placed on a document table 11 from above, a light source 13 for irradiating an image surface of the document, a plurality of mirrors 14, 14 and a lens 15 for guiding light reflected from the image surface of the document. The main component is an image processing unit 16 which is a photoelectric conversion unit having a function of performing photoelectric conversion of the reflected light by a CCD and performing various image processing on the obtained electric signals.

The image processing section 16 includes a CCD (not shown)
It has image processing functions such as / D conversion, S / H, shading correction, masking correction, scaling, and LOG conversion.

The operation of the reader unit 1 will be described.

A document is placed on a document table 11 such that the image surface faces downward, and the document is pressed from above by a document pressure plate 12. The light source 13 moves in the direction of arrow K1 while irradiating light, and scans the image surface of the document. The reflected light image from the image plane is transmitted to the CCD through a plurality of mirrors 14 and lenses 15.
It is imaged on, where it is photoelectrically converted to an electrical signal.

The image signal, which has been converted into an electric signal, is subjected to various image processing in the image processing section 16 and then transmitted to the next printer section 2.

As shown in FIG. 1, the printer unit 2 includes an image control unit 17 for converting an electric signal sent from the reader unit 1 into a signal for driving a laser, a laser element 18, and a photosensitive drum 30 described later. Scanner 19 that scans the surface of the lens with a laser beam, and a photosensitive drum 30 described later
And the fixing unit 39 disposed at the most downstream side as main components.

The image forming section 21 includes a photosensitive drum 30 rotatably supported in a direction indicated by an arrow, and a photosensitive drum 3 disposed around the photosensitive drum 30 substantially in the rotation direction.
, A developing device 20 for developing an electrostatic latent image on the photosensitive drum 30, a photosensitive drum 3
A transfer charger 35 for transferring the toner image on the transfer paper P to the transfer paper P;
A cleaner 34 for removing transfer residual toner adhered to the photosensitive drum 30, a cleaner blade 34a for scraping residual toner adhered to the photosensitive drum 30 inside the cleaner 34, an auxiliary charger 33 for removing static electricity, and a pre-exposure for removing residual charge. The lamp 32 and the like are configured as main components.

The developing device 20 further includes a developing roller 20.
a is provided. The developing roller 20 a rotates in a direction opposite to the photosensitive drum 30 so as to develop a toner image on the photosensitive drum 30.

The transfer paper P, which is a sheet on which the toner image has been transferred, is fixed by a fixing unit 39 by a conveying belt 38 before fixing.
Here, the fixing rollers 39a and 39b rotate and convey the transfer paper P to be pressurized, and are heated and pressurized to fix the toner image on the surface. Finally, the transfer paper P after fixing is discharged to a discharge tray 41 outside the copying machine main body by the post-fixing transfer belt 42.

A feeding and transporting unit for feeding and transporting the transfer paper P includes:
A sheet feeder having a transfer path for the transfer sheet P, an upper sheet feed cassette 36, a lower sheet feed cassette 37, a sheet feed roller and a transfer roller on the most upstream side in the transfer direction of the transfer sheet P, and a multi-sheet feeder 43 and the like.

Since the transfer paper feed path is straight from the multi paper feeder 43, various transfer papers having different transfer paper qualities such as material and size can be supplied to the image forming section 21. I can do it.

FIG. 2 is a block diagram showing a control system of the digital copying machine 10.

The copying machine 10 is entirely controlled by a system controller 101. Therefore, the system controller 101 mainly drives the respective loads in the copier 10, collects and analyzes information of sensors and the like, and in addition to the image processing unit 16 and the image control unit 17 described above, the operation unit 102, that is, the user interface Is responsible for the exchange of data.

Inside the system controller 101,
The CPU 101a is mounted to fulfill the role described above. The CPU 101a similarly executes various sequences related to a predetermined image forming sequence by a program stored in the ROM 101b mounted on the system controller 101. At this time, a RAM 101c for storing rewritable data that needs to be temporarily or permanently stored is also mounted. RA
The M101c includes, for example, a high-voltage set value to the high-voltage control unit 105 described later, various data described later, and the operation unit 102
Is stored. In addition, the CPU 101a includes timers such as a delay timer, a paper feed timer, a pre-registration timer, and a determination timer, which will be described later. Control such as detection and setting of the counts of these timers is performed by the timer unit 101d.

Next, the first of the system controller 101
The data exchange between the image processing unit 16, the image control unit 17, and the operation unit 102, which is the role of, will be described.

The system controller 101 and the image processing section 16 convert the image signal from the CCD (not shown) into an image, such as A / D conversion, S / H, shading correction, masking correction, scaling, and LOG conversion, as described above. Processing is being performed. The system controller 101, in addition to transmitting the specification setting value data of each unit required for the image processing, receives a signal from each unit, for example, a document image density signal, and outputs a high-voltage control unit 105 and an image Control unit 1
7 is set to perform optimal image formation.

The system controller 101 defines an image size for forming an image with the image controller 17,
The laser is optimally controlled based on the digital video data subjected to the image processing. That is, in the copying machine, settings necessary for performing the PWM processing of the laser emission are performed.

The system controller 101 operates the operation unit 1
02, in addition to obtaining information such as the copy magnification and the density set value set by the user, information on the state of the copying machine, for example, information on the number of formed images and whether or not an image is being formed, occurrence of a jam and its location And the like are sent to the user to indicate the above.

Next, the second of the system controller 101
The driving of each load in the copying machine and the information collection and analysis of sensors will be described.

At various points inside the copying machine 10, motors, DC loads such as clutches / solenoids, and sensors such as photointerrupters and microswitches are provided. That is, the system controller 101 controls the conveyance of the transfer paper and the drive control of each unit by appropriately driving the motor and the respective DC loads, and various sensors monitor the operation. Therefore, the system controller 101 controls each motor by the motor control unit 107 based on the signal from the various sensor signal processing unit 109 connected to the various sensors,
The DC load control unit 108 operates the clutch / solenoid to smoothly advance the image forming operation. Further, the system controller 101 sends various high-voltage control signals to the high-voltage control unit 105 so that the primary charger 31, the auxiliary charger 33, the transfer charger 35, the developing roller An appropriate high voltage is applied to 20a.

Further, each of the fixing rollers 39a and 39b in the fixing unit 39 has a built-in fixing heater 111 for heating the roller, and each heater is turned on / off by an AC driver 110. I have. At this time, the fixing rollers 39a, 39b
Is provided with a thermistor 104 for measuring its temperature.
The A / D 103 converts a change in the resistance value of the thermistor 104 according to a change in the temperature of each of the fixing rollers 39a and 39b into a voltage value, and then inputs the voltage value to the system controller 101 as a digital value. The above-described AC driver 110 is controlled based on the temperature data.

Next, with reference to FIG. 3, a description will be given of the paper feeder 40 for feeding and transferring the transfer paper P to the transfer position of the photosensitive drum 30 in the printer unit 2.

The paper feeding / conveying section 40 comprises a paper feeding section 44, a pre-registration correction section 45, a sheet interval determination section 46, a main registration correction section 47 and the like.

The paper supply section 44 is provided with a cassette 36 containing transfer paper (here, the upper cassette will be described.
A similar operation is performed for the lower sheet cassette 37). A roller 3 that picks up transfer sheets one by one from
71, a B roller 372 and a C roller 373 for separating the picked-up transfer sheets one by one.

The pre-registration correction unit 45 is provided with the B roller 37
2 and a pre-registration roller 374 for registering the transfer paper P separated by the C roller 373, a pre-registration sensor 375 used for controlling the pre-registration roller, and the like.

The paper interval determination unit 46 determines the interval between transfer papers when the transfer paper P is continuously fed.
2, a pre-registration roller 378 is provided in addition to a determination timer (not shown) provided in the CPU 101a of FIG.

The registration correcting section 47 detects a registration roller 376 for registering the transfer sheet when transferring the image latent image on the drum surface to the transfer sheet, and detects that the transfer sheet P reaches the registration roller 376. It is composed of a registration sensor 377 and the like.

In this copying machine, the transfer paper P is stored in the cassette 3
A, B, and C rollers 371 and 37 for extracting from rollers 6
A second driving source for driving the pre-registration roller 374 of the pre-registration correction 45 for conveying the transfer paper P, a fourth driving source for driving the pre-registration roller 378,
The third drive sources for driving the registration rollers 376 of the registration correction unit 47 are constituted by independent drive sources, respectively. In the present embodiment, the DC motors M1 (402) and M2 (4
03), M3 (404), and M4 (405).

Referring to FIG. 4, the paper feeding section 44 will be described in more detail. The paper feed unit 44 includes a paper feed pickup unit and a separation / conveyance unit.

The paper feeding section 44 is a section for feeding the transfer paper by an A roller 371 which picks up the transfer paper P one by one from the cassette 36 in which the transfer paper P is stored. The A roller 371 picks up the transfer paper by moving up and down according to a predetermined paper feed interval timing.

Next, a separation mechanism for separating the picked-up transfer paper one by one will be described. This separating mechanism portion includes a B roller 372 and a C roller 373 opposed to each other in FIG.
Are portions that convey one transfer sheet picked up by the A roller 371 by rotating each. Also, A
When a plurality of transfer papers are picked up by the roller 371, the C roller 373 is rotated in the reverse direction (rotated in the direction of the arrow), and the first (upper) transfer paper is separated by the B and C rollers 372 and 373. Thereafter, the lower (transfer) transfer paper P is dammed and separated. Here, when the paper is fed by the A roller 371, depending on the behavior of the first (upper) transfer paper P and the subsequent (lower) transfer paper, the transfer paper may be shifted with respect to the ON timing of the driving of the A roller 371. P is B, C rollers 372, 37
The amount of overrun passing through No. 3 varies. This variation is corrected by the pre-registration correction unit 47 described above.

Further, in this copying machine, in order to suppress the above-mentioned variation, the rotation speed of the motor M1 (402) of the first drive source is increased to thereby stably feed the paper with less variation in the overrun amount shown in FIG. Is going.

FIGS. 5 and 6 are flow charts showing a control procedure of the controller 101 of the copying machine according to the present invention, and show an example of sheet feeding and conveyance control of transfer paper.

When the paper feed control is started, step S is executed.
In step 501, if a delay timer, which will be described later, is counting, the process waits until the count ends.

Next, in step S502, the system controller 101 sets the CPU 101a every time a transfer sheet to be fed is sent out of the sheet cassette 36.
It is determined whether or not it is the last copy. If it is not the last sheet, in step S503, a sheet feed timer (not shown) is started in order to obtain the timing of sheet feed conveyance control of the next transfer sheet. Almost simultaneously, step S
In step 504, the A roller 371 is operated to feed the transfer paper.

Next, in step S506, a pre-registration timer for obtaining a timing for re-conveying the transfer sheet stopped later by the pre-registration correction section 45 is started immediately after the transfer sheet is fed from the sheet cassette 36. , Step S5
At step 06, the transfer paper is detected by the pre-registration sensor 375, and at step S507, the DC motor M2 (403) is stopped to stop the transfer paper at the pre-registration correction unit 45. If counting is in progress, wait until counting is completed. During this time, the transfer paper is pre-registered. Here, the delay timer is set by feed control of the previous transfer sheet when the transfer of the previous transfer sheet is delayed by a predetermined time or more, and the delay timer is set for the next transfer sheet by the timing of delay detection of the transfer sheet. Control to delay the sheet feeding (determination in step S501),
Alternatively, control for delaying re-transport from the pre-registration correction unit 45 (determination in step S508) is performed.

Next, in step S509, if the pre-registration timer is counting, the process waits until the count is completed. In step S510, the DC motor M2 (403) is operated, and the pre-registration correction unit 45 removes the stopped transfer paper. Re-transport.

Next, in step S511, the judgment sensor 3
If the transfer paper is detected by 79, step S512
It is determined whether or not the determination sensor use flag is set, and if not, in step S513,
The determination sensor use flag is set, and the process jumps to step S523. Note that the determination sensor use flag is set by the paper feed conveyance control of the previous paper when the conveyance of the previous paper has not been earlier arrived or delayed for a predetermined time with respect to the further previous paper. Then, the detection of the delay or the early arrival of the next transfer sheet is performed.

When it is determined in step S512 that the determination sensor use flag is set, in step S514, the count value of the determination timer for detecting delay and early arrival of the transfer sheet with respect to the previous transfer sheet is input. And
In step S515, the count value of the determination timer is set to CP.
Sent to U101a, the system controller 101 determines whether or not the reference value is within a predetermined range (the count value is equal to or greater than the predetermined range value). Jump to step S521.

The start and end of the count of the determination timer may be any of the following three cases.

In the first case, the registration roller 376 is started immediately after the previous transfer sheet is started to be conveyed, and ends when the leading edge of the next transfer sheet is detected by the determination sensor 379.

In the second case, the registration roller 376 is started immediately after the previous transfer sheet has been conveyed, and ends when the leading edge of the next transfer sheet is detected by the determination sensor 379.

The third case starts when the leading edge of the previous transfer sheet is detected by the determination sensor 379, and ends when the leading edge of the next conveyed transfer sheet is detected.

If it is determined in step S515 that the time has not been delayed (early arrival or normal arrival), the flow advances to step S515.
At 516, it is determined whether or not the count value of the determination timer has arrived early with respect to the reference value in the predetermined range (whether the count value is equal to or less than the predetermined range value), and it is determined that the wearer has not arrived early. In step S513, the determination sensor use flag is set in step S513, and the process jumps to step S523.

If it is determined in step S516 that the player has arrived early, in step S517, the DC motor M4 (405) and, if necessary, the DC motor M2
(403) is stopped, and the transfer sheet is stopped by the determination unit.

Next, in step S518, an early arrival timer for stopping and delaying the early arrival of the transfer paper that has arrived early is started. In step S519, when the counting of the early arrival timer is completed, step S520 is performed.
And a DC motor M4 (405) and, if necessary, a DC
By operating the motor M2 (403), the transfer paper is transported again.

Next, in step S521, when the transfer paper is delayed or prematurely arrived, a delay timer for delaying the conveyance of the next transfer paper by a predetermined time is started, and step S521 is executed.
At 522, the determination sensor use flag is reset so that the delay and early arrival detection by the determination sensor 379 is not performed on the next transfer sheet.

Next, in step S523, an image output timer for adjusting the timing of transferring the transfer paper and the timing of forming an image on the photosensitive drum 30 is started.
When the counting of the image output timer ends in step S524, an image is formed on the photosensitive drum 30 in step S525.

Next, in step S526, a registration timer for obtaining a timing for re-transporting the transfer paper stopped later to the registration unit 47 is started. At this time, the DC motor M3 (404) is stopped. In step S527, if the transfer sheet is detected by the registration sensor 377, a registration stop timer for stopping the leading end of the transfer sheet by forming a predetermined loop by the registration roller 376 is started in step S528, and step S529 is performed.
After the count of the registration stop timer ends, the DC motor M4 (405) and, if necessary, the DC motor M2 (403) are stopped in step S530, and the transfer sheet is stopped by the registration unit 47.

Next, in step S531, step S5
After the count of the registration-on timer started at 26 ends, at step S532, the DC motor M3 (40
4), DC motor M4 (405), and D
The transfer motor is operated again by operating the C motor M2 (403).

Next, in step S533, it is determined whether or not a determination sensor use flag for determining whether or not to perform delay and early arrival detection by the determination sensor 379 for the next transfer sheet is set. If the transfer has been performed (detection of delay and early arrival), in step S534, a determination timer for detecting delay and early arrival of the next transfer sheet is started, and the paper feed control ends.

Here, the control for feeding and transporting the next transfer sheet is performed when the count of the feed timer started in step S503 ends, and thereafter, the control for feeding and transporting the sheet until the final copy of the transfer sheet is repeated. Done.

In the above embodiment, the transfer control of the transfer paper in the digital copying machine is performed.
The present invention can be provided to other page printers such as a color copying machine and a printer, and the present invention is not limited to a digital copying machine.

[0078]

According to the sheet conveying apparatus of the present invention, when a sheet is fed from the sheet stacking means by the sheet feeding means and the sheet is conveyed by the first, second and third sheet conveying means, Is detected by the sheet interval determining means, and it is determined whether or not the distance is a predetermined interval. Based on this determination, the control means controls at least the first and second sheet conveying means to reduce the sheet interval. Can be sent at predetermined intervals.

The image forming apparatus of the present invention has a sheet conveying device capable of conveying a sheet at a predetermined interval when the interval between the sheets is narrowed. Therefore, the image forming apparatus can perform image forming without changing the image processing speed. Processing can be performed accurately at high speed.

[Brief description of the drawings]

FIG. 1 is a schematic front sectional view of a digital copying machine which is an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an example of a control system of the copying machine shown in FIG.

FIG. 3 is a schematic view of a portion that conveys a sheet from a cassette to a transfer position of a photosensitive drum.

FIG. 4 is a diagram illustrating a state in which sheets are fed from a cassette.

FIG. 5 is a flowchart illustrating a control procedure of a controller 101 of the copying machine of FIG. 1;

FIG. 6 is a flowchart showing a control procedure of a controller 101 of the copying machine shown in FIG. 1, following FIG. 5;

[Explanation of symbols]

 P Transfer paper (sheet) 10 Digital copier (image forming apparatus) 16 Image processing unit 17 Image control unit 21 Image forming unit (image forming unit) 30 Photosensitive drum 31 Primary charger 32 Pre-exposure lamp 33 Auxiliary charger 34 Cleaner 34a Cleaner blade 35 Transfer charging band 36 Upper paper cassette (sheet stacking means) 37 Lower paper cassette (sheet stacking means) 39 Fixing unit 40 Paper feed transport section 41 Paper discharge tray 44 Paper feed section (sheet feeding means) 45 Pre-register Correction unit (sheet conveyance unit) 46 Sheet interval judgment unit 47 Main registration correction unit (image formation conveyance unit) 101 System controller (control unit) 101a CPU (sheet interval judgment unit) 101b ROM 101c RAM 101d Timer unit (sheet interval judgment unit) ) 102 Operation unit 107 Motor control unit 109 Sensor signal processing unit 371 A roller (sheet feeding means) 372 B roller (sheet feeding means) 373 C roller (sheet feeding means) 374 Pre-registration roller (first sheet conveyance means) 375 Pre-registration sensor 376 Registration roller (third sheet conveyance means) 377 Registration sensor 378 Pre-registration roller (second sheet conveying means) 379 Judgment sensor (sheet interval judging means) 401 Solenoid (sheet feeding means) 402 DC motor M1 (sheet feeding means) 403 DC motor M2 (first sheet conveying means) 404 DC motor M3 (third sheet conveying means) 405 DC motor M4 (second sheet conveying means)

Continued on the front page (72) Inventor Tatsuhito Kataoka 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Yoshihiro Funami 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Stock In-house F term (reference) 3F048 AA02 AB01 BA05 BB02 BB08 CA04 DA06 DB07 DC12 EB22 EB29 EB30 3F049 EA22 EA23 EA28 EA29 LA04 LA07 LB03 3F343 FA02 FB02 GA01 GB01 GC01 GD01 JA01 KB06 LA03 LC09 MA03 MA15 MB03 MB03

Claims (10)

[Claims] A sheet feeding unit configured to feed the sheet from a sheet stacking unit on which the sheet is stacked; and a sheet feeding unit that is sequentially arranged downstream from the sheet stacking unit in a sheet feeding direction. A first sheet conveying unit, a second sheet conveying unit, and a third sheet conveying unit that detect passage of the sheet between the second sheet conveying unit and the third sheet conveying unit; A sheet interval determining unit that determines whether the interval is a predetermined interval; and the sheet feeding unit and the first sheet feeding unit so that the sheet can be conveyed at a predetermined interval based on the determination by the sheet interval determining unit. Among the sheet conveying means and the second sheet conveying means,
Control means for controlling at least the first sheet conveying means and the second sheet conveying means. 2. The method according to claim 1, wherein the control unit starts the third sheet conveying unit and starts conveying the previous sheet, and then determines a next sheet to be conveyed until the sheet interval determining unit detects the next sheet. 2. The sheet conveying apparatus according to claim 1, wherein conveying control of the next conveyed sheet is performed. 3. The control means drives the third sheet conveying means to complete the conveyance of the previous sheet, and based on the time until the next sheet to be conveyed is detected by the sheet interval judging means. 2. The sheet conveying apparatus according to claim 1, wherein conveying control of the next conveyed sheet is performed. 4. The control unit according to claim 1, wherein the control unit determines a next sheet to be conveyed based on a time period from when the previous sheet is detected by the sheet detection unit to when a next conveyed sheet is detected. The sheet conveyance device according to claim 1, wherein the conveyance control is performed. 5. The apparatus according to claim 1, wherein the sheet interval determination unit determines that the sheet interval is longer than a predetermined interval, determines that the sheet is delayed, and detects that the sheet interval is shorter than a predetermined interval. The sheet conveying device according to claim 1, wherein: 6. When the interval between the previous sheet and the next sheet is narrow, the control unit stops the second sheet conveying unit and determines the interval between the next sheet and the previous sheet. The interval between the next sheet and the further next sheet is set to the predetermined interval by further delaying the conveyance of the next sheet by a time corresponding to the time when the next sheet is delayed. The sheet conveying device according to claim 1, wherein: 7. When the interval between the previous sheet and the next sheet is narrow, the control unit stops the second sheet conveying unit and determines the interval between the next sheet and the previous sheet. 2. The sheet conveying apparatus according to claim 1, wherein the start of the sheet supply unit and the second sheet conveying unit is delayed by a predetermined time when the next sheet is conveyed and controlled. . 8. When the interval between the previous sheet and the next sheet is narrow, the control means stops the second sheet conveying means for a predetermined time and further conveys the next sheet. 2. The sheet conveying device according to claim 1, wherein the start of the sheet feeding unit and the second sheet conveying unit is delayed by a predetermined time. 9. The sheet conveying apparatus according to claim 1, wherein said first sheet conveying means and said third conveying means have registration rollers. 10. The image forming apparatus according to claim 1, further comprising: a sheet conveying device, and an image forming unit that forms an image on a sheet sent by the sheet conveying device. Image forming device.