JP3757672B2 - Image forming apparatus and conveyance control method for image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus, and more particularly, to control when a transfer sheet is conveyed at a high speed.
[0002]
[Prior art]
In image forming apparatuses such as copiers, printers, and facsimile machines, the time from the start of copying processing until the first copy paper is output (first copy time), and the copy paper per unit time The number of output sheets has been regarded as important.
[0003]
In order to improve these performances, it is desirable that the transfer of the transfer paper is carried out substantially continuously without delay in the image forming apparatus.
For this reason, when transporting from the paper feed tray or forming a double-sided image at a first transport speed that is twice that of the normal second transport speed at which the transfer paper passes through the registration roller, the photosensitive drum, and the fixing roller. It is preferable to use an image forming apparatus that performs reverse refeeding conveyance.
[0004]
The state of such an image forming apparatus is shown in FIG. In this way, when switching to a plurality of transport speeds, the loop forming roller 182 disposed in the transport path upstream of the registration roller 185 having a constant speed is switched using a clutch mechanism. Yes.
[0005]
That is, the loop forming roller 182 transports the transfer paper p at the first speed when transporting paper from the paper feed tray or reverse refeeding. However, the transfer paper p is transferred to the registration roller 185 and the loop forming roller. The loop forming roller 182 conveys at a second conveyance speed equal to that of the registration roller 185 when being nipped and conveyed by both of them.
[0006]
In this case, in the loop forming roller 182 that transports at a plurality of transport speeds, the electromagnetic clutch C1 is first turned on to transmit the rotational force from the drive source M1 to the loop forming roller 182 (FIGS. 6A and 6C). Thereafter, the electromagnetic clutch C2 is turned on to transmit the rotational force from the drive source M2 to the loop forming roller 182 (FIGS. 6B and 6C). During the period in which the electromagnetic clutch C2 is on, the registration roller is also driven by M2 at the same time (FIG. 6D).
[0007]
[Problems to be solved by the invention]
However, when a clutch mechanism is used for switching the conveyance speed, a switching time and a response time are required. When a general electromagnetic clutch is used, there is a response variation of about 50 milliseconds. Due to the presence of such variation in response, it is necessary to increase the transfer interval of the transfer paper, which sacrifices high speed.
[0008]
Further, when there are n types of transport speeds, n or (n-1) electromagnetic clutches are required.
When there are a plurality of m transport paths such as a paper feed cassette and a manual feed cassette, m times the number of electromagnetic clutches is required.
[0009]
For the reasons described above, problems such as an increase in the number of parts and a decrease in reliability and a problem of a decrease in high speed due to variations in response time have occurred. Accordingly, an object of the present invention is to realize an image forming apparatus having a simple configuration and causing no variation in response time when a transfer sheet is conveyed using a loop forming roller.
[0010]
[Means for Solving the Problems]
That is, the present invention for solving the above problems is as described below.
(1) The invention according to claim 1 is a photoconductor on which a toner image is formed, a transfer device for transferring the toner image formed on the surface of the photoconductor to transfer paper, and a transfer paper on which the toner image is transferred Is provided upstream of the registration rollers to form a loop in the transfer paper. An image forming apparatus comprising: a loop forming roller; a driving source that drives the registration roller and the loop forming roller; and a drive control unit that controls a driving state of the driving source. the a first driving source for driving the registration roller, independently provided for each of the second drive source for driving the loop forming roller, said drive control means, said register and said transfer sheet A first conveyance speed for causing the loop to be formed by contacting the roller is higher than a second conveyance speed for conveying the transfer sheet from the registration roller to the photosensitive member. performs control, when said conveying the transfer sheet to the photosensitive body, performs control for conveying drives and the resist roller and the loop forming roller by a second driving source and the first driving source An image forming apparatus characterized by that.
[0011]
In the present invention, the first drive source for driving the registration roller and the second drive source for driving the loop forming roller are independent, and when transferring the transfer paper onto the photosensitive member, Control is performed to drive and convey the registration roller and the loop forming roller by the second driving source.
[0012]
That is, since the switching of the conveyance speed by the loop forming roller is realized by the control of the second drive source, it is not necessary to use an electromagnetic clutch, and there is no response time variation or delay.
[0014]
(2) According to a second aspect of the invention, the drive control unit, according to claim 1 Symbol of the by second drive source control is performed to drive by switching the loop forming roller into a plurality of transport speed, characterized in that Image forming apparatus.
[0015]
In the present invention, since the drive control means performs control to switch the loop forming roller to a plurality of transport speeds, it is possible to switch and control the transport speed of the loop forming rollers independently of the registration rollers.
[0017]
In the invention of (1) , the transfer paper is transported from the registration roller to the photoconductor, and the transfer paper is transported from the registration roller to the photoconductor. Since the control is performed so that the first conveyance speed and the second conveyance speed are different from each other, the conveyance speed of the loop forming roller is switched independently of the registration rollers. It becomes possible to control.
[0018]
The invention of (1) is the image forming apparatus according to claim 4, wherein the first transport speed is higher than the second transport speed. In the present invention, control is performed so that the first conveyance speed for forming the loop by abutting the transfer paper against the registration roller is higher than the second conveyance speed for conveying the registration roller to the photosensitive member. Therefore, high-speed image formation becomes possible.
[0028]
( 3 ) The invention according to claim 3 is a photoconductor on which a toner image is formed, a transfer device for transferring the toner image formed on the surface of the photoconductor to a transfer paper, and a transfer paper on which the toner image is transferred A paper feed tray for storing the paper, a registration roller that transports the transfer paper that is sent out and abutted from the paper feed tray onto the photoconductor, and upstream of the registration roller for transporting the transfer paper to the registration roller. A plurality of conveying paths provided; a plurality of loop forming rollers respectively provided in the plurality of conveying paths to form a loop on the transfer paper; a common drive source for driving the plurality of loop forming rollers; and the driving an image forming apparatus configured with a drive control means for controlling the driving state of the source, the drive control means, the formation of the loop abutted against the transfer sheet to the registration roller First transport speed to Migihitsuji is, performs control the transfer sheet such that the faster than the second conveying speed to perform the transport to the photoreceptor from the registration roller, the rotation of the drive source An image forming apparatus characterized in that control is performed to independently drive each loop forming roller by switching directions.
[0029]
In this invention, it becomes possible to drive a plurality of loop forming rollers independently by switching the rotation direction of a common drive source. For this reason, even when there are a plurality of transport paths, there is no need to use an electromagnetic clutch when switching the loop forming roller to be driven or switching the transport speed, and there will be no variation or delay in response time. .
In the present invention, the first conveyance speed for causing the transfer paper to abut against the registration roller to form a loop is the second conveyance speed for carrying the transfer paper from the registration roller to the photosensitive member. Control is performed so that the speed is higher than the conveyance speed and the rotation direction of the driving source is switched to control each loop forming roller independently. The roller conveyance speed can be switched and controlled, and high-speed image formation is possible.
[0030]
( 4 ) In the invention according to claim 4 , the drive control means causes the drive source to feed each of the loop forming rollers to a plurality of transport speeds so that the transfer paper is transported at different transport speeds in the plurality of transport paths. The image forming apparatus according to claim 4, wherein control for driving is performed while switching to the image forming apparatus.
[0031]
In the present invention, since control for switching each loop forming roller to a plurality of transport speeds is performed, it is possible to switch and control the transport speed of each loop forming roller independently of the registration rollers.
[0032]
(5) The invention according to claim 5 is a photoconductor on which a toner image is formed, a transfer device for transferring the toner image formed on the surface of the photoconductor to transfer paper, and a transfer paper on which the toner image is transferred A paper feed tray for storing the paper, a registration roller that transports the transfer paper that is sent out and abutted from the paper feed tray onto the photoconductor, and upstream of the registration roller for transporting the transfer paper to the registration roller. A plurality of conveying paths provided; a plurality of loop forming rollers respectively provided in the plurality of conveying paths to form a loop on the transfer paper; a common drive source for driving the plurality of loop forming rollers; and the driving An image forming apparatus configured to include a drive control unit that controls a drive state of the source, wherein the drive control unit switches each rotation direction of the drive source to change each loop. The driving control unit performs control for independently driving the forming rollers, and the drive control unit controls the plurality of loop forming rollers by the driving source so that the transfer paper is transported at different transport speeds in the plurality of transport paths. The image forming apparatus is characterized in that it is controlled to be switched to a different conveyance speed.
In this invention, it becomes possible to drive a plurality of loop forming rollers independently by switching the rotation direction of a common drive source. For this reason, even when there are a plurality of transport paths, there is no need to use an electromagnetic clutch when switching the loop forming roller to be driven or switching the transport speed, and there will be no variation or delay in response time. . Since the control for switching each loop forming roller to a plurality of transport speeds is performed, the transport speed of each loop forming roller can be switched and controlled independently of the registration rollers.
( 6 ) The invention according to claim 6 is characterized in that one of the plurality of transport paths is a transport path for transporting the transfer paper from the manual feed tray . The image forming apparatus according to any one of the above.
[0033]
In the present invention, control is performed to switch each loop forming roller to a plurality of transport speeds, one of which is a transport path from the manual feed tray, which enables high-speed transport from the manual feed tray.
[0038]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing an example of the electrical configuration of the main part of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram showing the overall configuration of the image forming apparatus according to the embodiment of the present invention. 3 is a side sectional view showing a mechanical configuration of the image forming apparatus according to the embodiment of the present invention.
[0039]
First, the entire image forming apparatus will be described with reference to FIGS. In FIG. 2, reference numeral 10 denotes an automatic document feeder (hereinafter also referred to as ADF), which is a device for carrying a document for reading. An image reading unit 20 optically scans and reads a document to generate image data. An image forming unit 50 records image data on a recording medium (hereinafter referred to as transfer paper) p by electrophotography.
[0040]
Reference numeral 100 denotes a CPU as a control means for controlling each unit, and controls each unit according to a processing program (not shown).
Reference numeral 110 denotes an operation unit for performing various operations such as selecting and specifying the number of copies, enlargement / reduction ratio, transfer paper size (A4, A4R, B5, B5R), and starting copying, and the operation results are transmitted to the CPU 100. The
[0041]
An ADF control unit 120 controls the document conveyance of the ADF 10 and controls the document conveyance state in accordance with an instruction from the CPU 100. Reference numeral 130 denotes an image memory as storage means for storing the compressed image data, and is composed of a memory capable of storing (storing) and reading (output).
[0042]
A read image processing unit 140 processes image data read by the image reading unit 20. A compression / decompression circuit 150 performs a compression process for writing the image data processed by the read image processing unit into the image memory 130 and a decompression process for decompressing the compressed image data read from the image memory 130. It is. Reference numeral 160 denotes a recorded image processing unit that processes image data that has been decompressed and returned to its original state for image formation.
[0043]
Reference numeral 170 denotes a drive control unit that controls the driving state of a driving source, which will be described later, and controls transfer paper conveyance. This is the second drive source.
[0044]
FIG. 3 is a configuration diagram showing a cross-sectional configuration of the image forming apparatus used in the embodiment of the present invention. In FIG. 3, a plurality of documents d with the surface of the first page of the document facing up is placed on the document placement portion 11 of the ADF 10 capable of carrying both sides of the document. The first sheet of the document sent out through the rollers 12 a and 12 b is conveyed through the roller 13.
[0045]
At this time, the original surface of the original d is irradiated by the light source 23, and the reflected light forms an image on the light receiving surface of the CCD 28 which is a photoelectric conversion means via the mirrors 24, 25 and 26 and the imaging optical system 27. Here, the light source 23, the mirrors 24, 25, and 26, the optical system having the imaging optical system 27 and the CCD 28, and the optical system driving means (not shown) constitute the image reading unit 20.
[0046]
In FIG. 3, when reading an original d placed on the platen glass 21 with the reading surface facing downward, the optical system is scanned along the platen glass 21 for reading.
[0047]
When reading the document d while being conveyed, the reading is performed with the light source 23 and the mirror 24 fixed under the second platen glass 22. Then, the read image data of the document d is sent from the CCD 28 to a read image processing unit 140 (not shown).
[0048]
When the original d is conveyed on both sides by the ADF 10, when the first page of the original d is read, the original d is conveyed again to the roller 13 via the reverse roller 14, and the image on the back side of the original is read by the image reading unit. 20, and the read image data is sent to the read image processing unit 140.
[0049]
In this way, the document d from which the images on the front surface and the back surface are read is reversed again by the reversing roller 14 and is discharged and stacked on the paper discharge tray 16 with the front surface facing downward.
[0050]
The image data read by the image reading unit 20 in this manner is subjected to predetermined image processing by the read image processing unit 140 and then compressed by the compression / decompression circuit 150 and stored in the image memory 130.
[0051]
On the other hand, the transfer paper p is fed out from the paper feed cassette 30 on which the transfer paper is stacked by the transport roller 181 and transported to the image forming unit 50. Further, the transfer paper p is sent out from the manual feed tray 31 by the transport roller 183 and transported to the image forming unit 50.
[0052]
The transfer sheet p conveyed to the image forming unit 50 is fed to the surface of the photosensitive drum 51 serving as an image carrier after being timed by a registration roller 185 near the entrance. That is, a first transport path from the paper feed cassette 30 to the registration rollers 185 and a second transport path from the manual feed tray 31 to the registration rollers 185 are provided.
[0053]
Image data is input from the recorded image processing unit 160 to the image writing unit 40, and a laser beam corresponding to the image data is irradiated onto the photosensitive drum 51 from a laser diode in the image writing unit 40 to form an electrostatic latent image. . The electrostatic latent image is developed by the developing unit 53 to form a toner image on the photosensitive drum 51.
[0054]
This toner image is transferred to the transfer paper p by the transfer section 54 below the photosensitive drum 51. Then, the transfer paper p in contact with the photosensitive drum 51 is separated by the separation unit 55. The transfer paper p separated from the photosensitive drum 51 enters the fixing unit 59 via the transport mechanism 58, and the toner image is fixed by heat and pressure. In this way, an image is formed on the transfer paper p.
[0055]
Note that when reversal re-feeding is necessary when forming a double-sided image, the transfer paper p on which the toner image is fixed is conveyed downward through the guide 61 and enters the reversing unit 63. Next, the transfer paper p that has entered the reversing unit 63 is sent out again by the reverse conveying roller 65, and is sent again to the image forming unit 50 via the reverse conveying path 64. In the image forming unit 50 where the image formation on one side of the original d has been completed, the toner remaining on the photosensitive drum 51 is removed by the cleaning unit 56 to prepare for the next image formation.
[0056]
In this state, the other side of the transfer paper p (the side on which no image is formed yet) is carried into the image forming unit 50 to form an image. The transfer paper p separated from the photosensitive drum 51 by the separation unit 55 enters the fixing unit 59 again through the transport mechanism 58 and is fixed. In this way, the transfer paper p on which image formation on the back surface and the front surface is completed, or the transfer paper p on which image formation on one surface is completed is discharged outside the apparatus.
[0057]
Here, details of the periphery of the drive control means 170 will be described with reference to FIG. As shown in FIG. 1, the drive control means 170 includes an oscillation source (oscillator) 171 that generates a basic clock having a predetermined frequency, a frequency divider 172 that divides the basic clock according to settings from the CPU 100, and a basic clock. A frequency divider 173 that divides frequency by setting a frequency dividing ratio from the CPU 100, a driver 174 that generates a drive pulse for driving the stepping motor SMa from the frequency-divided signal divided by the frequency divider 172, and a frequency divider 173 A driver 175 for generating a drive pulse for driving the stepping motor SMb from the divided signal.
[0058]
In this embodiment, it is preferable that the single oscillation source 171 be used so that the synchronization can be improved and the cost can be reduced. However, an oscillation source may be provided corresponding to each of the drivers 174 and 175.
[0059]
Further, the loop forming roller 182 and the registration roller 185 constitute a transport roller for switching the speed while transporting a single transfer sheet. Here, the registration roller 185 is driven by a first drive source (stepping motor SMa), and the loop forming roller 182 is driven by a second drive source (stepping motor SMb). In order to realize such an independent drive source,
The frequency divider 172 and the frequency divider 173 of the drive control means 170 are configured such that the frequency division ratio is set independently from the CPU 100.
[0060]
The transmission unit 190 can distribute (switch) the rotational force from the stepping motor SMb to the loop forming roller 182 on the first transport path side and the loop forming roller 184 on the second transport roller side. It is. For this reason, the drive mechanism supplies a rotational force to one of the conveying rollers according to the rotation direction (forward / reverse rotation) of the stepping motor SMb.
[0061]
As this drive mechanism, for example, it is effective to provide one-way clutches (one-way clutches) in opposite directions to the respective conveyance rollers.
4 shows the rotation speed of the stepping motor SMb (FIG. 4A), the transfer paper conveyance speed by the loop forming roller 182 (rotational peripheral speed of the loop forming roller 182: FIG. 4B), and the loop forming roller 185. 5 is a characteristic diagram showing the transfer paper conveyance speed (rotational peripheral speed by the loop forming roller 185: FIG. 4C) and the rotational speed of the stepping motor SMb (FIG. 4D). Note that the rotation speed of the stepping motor SMa (FIG. 4D) corresponds to the transfer paper conveyance speed by the registration rollers 185.
[0062]
Here, in the period A in FIG. 4, the stepping motor SMb rotates in the cw (clockwise) direction, and the rotation in the cw direction is transmitted to the loop forming roller 182 via the transmission unit 190. As a result, the loop forming roller 182 can obtain the first conveying speed (2S). During the period A, the transfer paper p is abutted against the registration roller 185 on the first conveyance path side and conveyed until a loop is formed.
[0063]
In the period B in FIG. 4, the stepping motor SMb rotates in the cw (clockwise) direction, and the rotation in the cw direction is transmitted to the loop forming roller 182 via the transmission unit 190. As a result, the second conveyance speed (S) is obtained by the loop forming roller 182. Also, during this period B, the stepping motor SMa is also rotating, and the second conveying speed (S) is obtained by the registration roller 185. That is, during the period B, the transfer paper p is conveyed at the same conveyance speed (S) while being sandwiched between the loop forming roller 182 and the registration roller 185.
[0064]
Here, the first drive source for driving the registration roller 185 and the second drive source for driving the loop forming roller 182 are independent, and when the transfer paper p is conveyed onto the photosensitive member 51, the first drive source is driven. Control is performed so that the registration roller 185 and the loop forming roller 182 are individually driven and conveyed by the driving source and the second driving source, respectively. That is, since the switching of the conveyance speed by the loop forming roller 182 is realized by the control of the second drive source, there is no need to use an electromagnetic clutch as in the prior art, and the response time does not vary or delay.
[0065]
Further, since the loop forming roller 182 is driven by the stepping motor SMb, the transfer speeds (2S and S) can be easily switched and accurately controlled.
[0066]
Further, since the drive control unit 170 controls the first drive source and the second drive source separately, it is possible to switch and control the conveyance speed of the loop forming roller 182 independently of the registration roller 185. become.
[0067]
In addition, since control is performed so that the first transport speed and the second transport speed are different on the loop forming roller 182 side, the transport speed of the loop forming roller 182 is switched and controlled independently of the registration roller 185. It becomes possible.
[0068]
Further, the first transport speed (2S) for forming the loop by abutting the transfer paper p against the registration roller 185 is different from the second transport speed (S) for transporting from the registration roller 185 to the photoconductor 51. Since the speed is controlled to be high, the transfer paper can be conveyed quickly and high-speed image formation is possible.
[0069]
Further, not only the loop forming roller 182 side but also the registration roller 185 side uses a stepping motor as a drive source, so that the conveyance speed can be easily maintained and controlled, and a loop is formed when the transfer paper p is conveyed to the photoreceptor 51. It becomes possible to maintain the state synchronized with the roller 182.
[0070]
In the period C in FIG. 4, the stepping motor SMb rotates in the ccw (counterclockwise) direction, and the rotation in the ccw direction is transmitted to the loop forming roller 184 via the transmission unit 190. As a result, the loop forming roller 184 obtains the first conveying speed (2S). During the period C, the transfer paper p is abutted against the registration roller 185 on the second conveyance path side and conveyed until a loop is formed.
[0071]
In the period D in FIG. 4, the stepping motor SMb rotates in the ccw (clockwise) direction, and the rotation in the ccw direction is transmitted to the loop forming roller 184 via the transmission unit 190. Thereby, the second transport speed (S) is obtained by the loop forming roller 184. Further, the stepping motor SMa is also rotating during the period D, and the second transport speed (S) is obtained by the registration roller 185. That is, during the period D, the transfer paper p is conveyed at the same conveyance speed (S) while being sandwiched between the loop forming roller 184 and the registration roller 185.
[0072]
Here, the effects obtained by the independent driving of the registration roller 185 and the loop forming roller 184 in the period C and the period D are equal to the effects in the period A and the period B described above.
[0073]
Further, when the period A to the period B and the period C to the period D are compared, the following effects can be obtained.
Here, a common drive source can be shared by a plurality of loop forming rollers respectively provided in a plurality of conveyance paths, and a plurality of loop forming rollers can be driven independently by switching the rotation direction of the common drive source. I have to. For this reason, even when there are a plurality of conveyance paths, it is not necessary to use an electromagnetic clutch when switching each loop forming roller to be driven, and variations in response time and delay do not occur.
[0074]
In addition, since control for switching each loop forming roller to a plurality of transport speeds is performed, it is possible to switch and control the transport speed of each loop forming roller independently of the registration rollers.
[0075]
Furthermore, one of the plurality of transport paths can be used as a transport path for transporting transfer paper from the manual feed tray, and high-speed transport can be performed from the manual feed tray.
[0076]
【The invention's effect】
As described above in detail, in the present invention, the first drive source for driving the registration roller and the second drive source for driving the loop forming roller are independent, and the transfer paper is conveyed onto the photoreceptor. In this case, control is performed such that the registration roller and the loop forming roller are driven and conveyed by the first driving source and the second driving source, respectively. That is, since the switching of the conveyance speed by the loop forming roller is realized by the control of the second drive source, it is not necessary to use an electromagnetic clutch, and there is no response time variation or delay.
[0077]
Further, in the present invention, a common drive source is shared by the respective loop forming rollers provided in the plurality of transport paths, and the plurality of loop forming rollers are independently driven by switching the rotation direction of the common drive source. Is possible. For this reason, even when there are a plurality of transport paths, there is no need to use an electromagnetic clutch when switching between a plurality of loop forming rollers to be driven and a transport speed, and variations in response time and delays do not occur.
[Brief description of the drawings]
FIG. 1 is a functional block diagram showing an electrical configuration of main parts of an image forming apparatus according to an embodiment of the present invention.
FIG. 2 is a functional block diagram showing an overall electrical configuration of the image forming apparatus according to the embodiment of the present invention.
FIG. 3 is a configuration diagram illustrating a mechanical configuration of an image forming apparatus according to an exemplary embodiment of the present invention.
FIG. 4 is an explanatory diagram showing a drive frequency pattern during operation of the image forming apparatus according to the embodiment of the present invention.
FIG. 5 is an explanatory diagram illustrating a state during operation of a conventional image forming apparatus.
FIG. 6 is an explanatory diagram illustrating a state during operation of a conventional image forming apparatus.
[Explanation of symbols]
10 ADF (automatic document feeder)
20 Image Reading Unit 30 Paper Feed Cassette 31 Manual Tray 40 Image Writing Unit 50 Image Forming Unit 100 CPU
110 Operation Unit 120 ADF Control Unit 130 Image Memory 140 Read Image Control Unit 150 Compression / Expansion Circuit 160 Recorded Image Processing Unit 170 Drive Control Unit 171 Oscillation Source 172 Frequency Divider 173 Frequency Dividers 174, 175 Driver 181 Transport Roller 182 Loop Forming Roller (On the first transport path)
183 Conveying roller 184 Loop forming roller (on the second conveying path)
185 Registration roller SMa First drive source (stepping motor)
SMb second drive source (stepping motor)
190 Transmitter

Claims (6)

A photoconductor on which a toner image is formed, a transfer device that transfers the toner image formed on the surface of the photoconductor to transfer paper, a paper feed tray that stores transfer paper on which the toner image is transferred, and the paper feed tray A registration roller that transports the transfer paper that has been delivered and abutted onto the photoconductor, a loop forming roller provided upstream of the registration roller to form a loop on the transfer paper, the registration roller and the loop An image forming apparatus configured to include a drive source that drives a forming roller, and a drive control unit that controls a drive state of the drive source,
The drive source is provided independently for each of a first drive source for driving the registration roller and a second drive source for driving the loop forming roller,
The drive control means causes the transfer paper to be transported from the registration roller to the photosensitive member at a first transport speed that causes the transfer paper to abut against the registration roller to form a loop. the second performs a control such that the faster transport speed, wherein when conveying the transfer sheet to the photosensitive body, the resist roller and said loop by said second driving source and the first drive source for Control to drive and drive the forming roller,
An image forming apparatus. The drive control means performs control to switch the loop forming roller to a plurality of transport speeds by the second drive source.
The image forming apparatus according to claim 1. A photoconductor on which a toner image is formed, a transfer device that transfers the toner image formed on the surface of the photoconductor to transfer paper, a paper feed tray that stores transfer paper on which the toner image is transferred, and the paper feed tray A registration roller that transports the transfer paper that has been delivered and abutted onto the photosensitive member, a plurality of transport paths provided upstream of the registration roller for transporting the transfer paper to the registration roller, A plurality of loop forming rollers provided in each of the plurality of conveying paths to form a loop; a common drive source for driving the plurality of loop forming rollers; and a drive control means for controlling a drive state of the drive source. An image forming apparatus configured to include:
The drive control means causes the transfer paper to be transported from the registration roller to the photosensitive member at a first transport speed that causes the transfer paper to abut against the registration roller to form a loop. The control is performed so as to be higher than the second transport speed, and the control is performed to independently drive each loop forming roller by switching the rotation direction of the drive source.
An image forming apparatus. The drive control means performs control to switch each of the loop forming rollers to a plurality of conveyance speeds by the drive source so that the transfer paper is conveyed at different conveyance speeds in the plurality of conveyance paths.
The image forming apparatus according to claim 3. Photoreceptor bets toner image is formed on the surface, the paper feed tray transferring device for transferring a transfer paper a toner image formed on the surface of the photosensitive member, the toner image is accommodated a transfer paper is transferred, the sheet feeding A registration roller that transports the transfer paper that has been delivered from and abutted on the tray onto the photosensitive member, a plurality of transport paths provided upstream of the registration roller for transporting the transfer paper to the registration roller, and transfer paper A plurality of loop forming rollers respectively provided in the plurality of transport paths to form a loop, a common driving source for driving the plurality of loop forming rollers, and a drive control means for controlling the driving state of the driving source An image forming apparatus configured to include:
Said drive control means, by switching the rotational direction of the driving source performs independently controlled to drive the respective loops forming roller, also, the drive control unit, the transfer sheet in the plurality of transport path Control to switch each of the loop forming rollers to a plurality of transport speeds by the drive source so as to be transported at different transport speeds;
An image forming apparatus. One of the plurality of transport paths is a transport path for transporting transfer paper from a manual feed tray.
The image forming apparatus according to claim 3 , wherein the image forming apparatus is an image forming apparatus.

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