JPH08190280A - Image forming device - Google Patents

Abstract

PURPOSE: To prevent generation of a drum flaw due to speed difference between the circumferential speed of a photoreceptor drum and the moving speed of a transfer belt by confirming matching of the both speed, and actuating the transfer belt unit in a transfer position. CONSTITUTION: The image forming device is provided with the photoreceptor drum 3 and the transfer belt unit 60 equipped with the transfer belt 68 disposed opposite to the photoreceptor drum 3. Moreover, the device is provided with a contacting/leaving means 110 of the transfer belt unit 60, the photoreceptor drum driving device 30, a transfer belt driving mans, the first speed detection means for detecting the circumferential speed of the photoreceptor drum 3, the second speed detection means for detecting the moving speed of the transfer belt 68, and the control means. The photoreceptor drum driving device 30 and the transfer belt driving means are respectively drive-controlled based on the image forming start signal by the control means, and the contact/uncontact means 110 is actuate-controlled when the circumferential speed of the photoreceptor drum 3 matches with the moving speed of the transfer belt 68, based on the respective detection signals from the first speed detection means and the second speed detection signal 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 machine such as an electrophotographic device or an electrostatic recording device, and more particularly, a transfer device for transferring a toner image formed on the outer peripheral surface of a photosensitive drum onto a transfer paper. The present invention relates to an image forming machine including a transfer belt unit.

[0002]

2. Description of the Related Art In an image forming machine, a transfer system using corona discharge is generally used as a system for transferring a toner image formed on a photosensitive drum onto a transfer paper. However, this transfer method using corona discharge has problems that the transferability at high humidity is poor and that transfer failure is likely to occur due to dirt on the corona wire, wrinkles on the transfer paper, and the like. As a means for solving such a problem, a driving roller, a driving roller arranged at a distance from the driving roller, a transfer belt stretched between the driving roller and the driving roller, A transfer belt unit including a transfer roller arranged opposite to the photoconductor drum with the transfer belt interposed therebetween is arranged opposite to the photoconductor drum, and a high voltage is applied to the transfer roller to move the transfer belt. Transfer method transfer, in which the toner image formed on the surface of the photoconductor drum is sequentially attracted and transferred to the transfer paper supplied between the photoconductor drum and the transfer belt by being charged to a predetermined polarity. The device is, for example, Japanese Patent Application Laid-Open
No. 345183. In an image forming machine equipped with a transfer device of such a transfer system, the transfer belt unit is easily deformed or deteriorates early when the transfer belt is pressed against the photosensitive drum even when the transfer belt is not transferred. Is separated from the photosensitive drum. At the same time when the copy start switch is turned on, the photosensitive drum and the transfer belt are driven and the transfer belt unit is operated to the transfer position.

[0003]

There is no problem when the photosensitive drum and the transfer belt are driven by the same motor, but in the case where the photosensitive drum and the transfer belt are driven by different motors, Since a manufacturing error occurs in the rise time of the motors, a time difference occurs before both motors reach the specified rotation speed. Therefore, a speed difference occurs between the peripheral speed of the photosensitive drum and the moving speed of the transfer belt until both motors reach the specified rotation speed.
Therefore, when the transfer belt unit is moved to the transfer position and the transfer belt is pressed against the photosensitive drum until both motors reach the specified rotation speed, the surface of the photosensitive drum is abraded by the speed difference. May cause damage or damage to the drum. Further, since the photosensitive drum and the transfer belt, which have different peripheral speeds and moving speeds, come into contact with each other, the load on both motors for driving them increases, and the time required for both motors to reach the specified speed increases. is there.

The present invention has been made in view of the above points, and its main technical problem is to confirm that the peripheral speed of the photosensitive drum and the moving speed of the transfer belt are the same, and then the transfer belt unit is confirmed. It is an object of the present invention to provide an image forming machine capable of eliminating the above-mentioned inconvenience caused by the above-mentioned speed difference by operating the transfer position to the transfer position.

Another technical problem of the present invention is that the transfer is performed before the transfer belt unit is operated to the transfer position after confirming that the peripheral speed of the photoconductor drum and the moving speed of the transfer belt match. An object of the present invention is to provide an image forming machine capable of shortening an image forming time by executing a so-called primary sheet feeding operation of conveying a sheet to a position immediately before a transfer belt unit.

[0006]

In order to achieve the above-mentioned technical object, according to the first invention, a photosensitive drum on which a toner image is formed on an outer peripheral surface, a driving roller, and an interval between the driving roller are provided. A transfer belt unit having a driving roller arranged in a stand-by manner, a driving roller and a transfer belt stretched on the driving roller and arranged to face the photosensitive drum, and the transfer belt unit. A contact / separation unit for operating the transfer position and the non-transfer position, a photosensitive drum driving unit for rotating the photosensitive drum, a transfer belt driving unit for operating the transfer belt, and a peripheral speed of the photosensitive drum are detected. First speed detecting means, second speed detecting means for detecting the moving speed of the transfer belt, and drive control of the photosensitive drum driving means and the transfer belt driving means based on an image formation start signal. Rutotomoni, based on the detection signal from the speed detecting means and the second speed detecting means of the first,
An image, comprising: a control unit that controls the operation of the contact / separation unit to operate the transfer belt unit to the transfer position when the peripheral speed of the photosensitive drum and the moving speed of the transfer belt match. A forming machine is provided.

According to the second aspect of the invention, the photosensitive drum on the outer peripheral surface of which a toner image is formed, the driving roller, the sliding roller arranged at a distance from the driving roller, the driving roller, and the driving roller. A transfer belt unit having a transfer belt stretched around a moving roller and arranged to face the photosensitive drum, a contacting / separating unit for operating the transfer belt unit at a transfer position and a non-transfer position, and the photosensitive member. A transfer paper supply device for supplying transfer paper between the body drum and the transfer belt unit,
Photosensitive drum driving means for rotating the photosensitive drum, transfer belt driving means for operating the transfer belt, transfer paper supply roller driving means for driving the transfer paper supply device, and peripheral speed of the photosensitive drum For detecting the moving speed of the transfer belt, a second speed detecting means for detecting the moving speed of the transfer belt, and drive control of the photosensitive drum driving means and the transfer belt driving means based on an image formation start signal. In addition, the transfer paper supply roller driving means is driven to control the primary feeding of the transfer paper to the position immediately before the transfer belt unit, and the detection signals from the first speed detecting means and the second speed detecting means are provided. Based on the above, when the peripheral speed of the photosensitive drum and the moving speed of the transfer belt match, the contact / separation device is operated and controlled to operate the transfer belt unit to the transfer position. Image-forming machine is provided which is characterized by comprising a stage, a.

According to the third aspect of the invention, the photosensitive drum on which the toner image is formed on the outer peripheral surface, the driving roller, the sliding roller arranged at a distance from the driving roller, the driving roller and the driving roller are provided. A transfer belt unit having a transfer belt stretched around a moving roller and arranged to face the photosensitive drum, a contacting / separating unit for operating the transfer belt unit at a transfer position and a non-transfer position, and the photosensitive member. A photosensitive drum driving means for rotating the body drum, a transfer belt driving means for operating the transfer belt, and a driving control of the photosensitive drum driving means and the transfer belt driving means based on an image formation start signal, After a lapse of a predetermined time from driving the photosensitive drum driving means and the transfer belt driving means, the contact / separation means is operated and controlled to move the transfer belt unit to the transfer position. Image-forming machine is provided which is characterized by comprising a Mel control means.

According to the fourth aspect of the invention, the photosensitive drum on which the toner image is formed on the outer peripheral surface, the driving roller, the sliding roller arranged at a distance from the driving roller, the driving roller and the driving roller are provided. A transfer belt unit having a transfer belt stretched around a moving roller and arranged to face the photosensitive drum, a contacting / separating unit for operating the transfer belt unit at a transfer position and a non-transfer position, and the photosensitive member. A transfer paper supply device for supplying transfer paper between the body drum and the transfer belt unit,
Based on a photoconductor drum drive means for rotating the photoconductor drum, a transfer belt drive means for operating the transfer belt, a transfer paper supply roller drive means for driving the transfer paper supply device, and an image formation start signal. The photosensitive drum drive means and the transfer belt drive means are drive-controlled, and the transfer paper supply roller drive means is driven to control the primary feeding of the transfer paper to a position immediately before the transfer belt unit, and the photosensitive body An image, comprising: a drum driving means and a control means for controlling the operation of the contacting / separating means to move the transfer belt unit to a transfer position after a predetermined time has elapsed after driving the drum driving means and the transfer belt driving means. A forming machine is provided.

[0010]

In the image forming machine according to the present invention, when the image forming start signal is issued, the control means drives and controls the photosensitive drum driving means and the transfer belt driving means. Then, the control means controls the operation of the contacting / separating device based on the detection signals from the first speed detecting means and the second speed detecting means when the peripheral speed of the photosensitive drum and the moving speed of the transfer belt match. Move the transfer belt unit to the transfer position.

Further, in the image forming machine according to the present invention, when the image forming start signal is issued, the control means drives and controls the photosensitive drum driving means and the transfer belt driving means, and also drives the transfer paper supply roller driving means. Then, the primary feeding of the transfer paper is controlled up to the position immediately before the transfer belt unit. The control means includes the first speed detecting means and the second speed detecting means.
When the peripheral speed of the photosensitive drum and the moving speed of the transfer belt match based on the detection signal from the speed detecting means, the contact / separation device is controlled to operate the transfer belt unit to the transfer position.

Further, in the image forming machine according to the present invention, when the image forming start signal is issued, the control means drives and controls the photosensitive drum driving means and the transfer belt driving means and sets the timer to a predetermined time. Then, the control means controls the operation of the contacting / separating means to move the transfer belt unit to the transfer position after a lapse of a predetermined time after driving the photosensitive drum drive means and the transfer belt drive means.

Further, in the image forming machine according to the present invention, when the image forming start signal is issued, the control means drives and controls the photosensitive drum driving means and the transfer belt driving means, and sets the timer to a predetermined time, Further, the transfer sheet supply roller driving means is driven to control the primary sheet feeding of the transfer sheet up to the position immediately before the transfer belt unit. Then, the control means controls the operation of the contacting / separating means to move the transfer belt unit to the transfer position after a lapse of a predetermined time after driving the photosensitive drum drive means and the transfer belt drive means.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A more detailed description will be given below with reference to the accompanying drawings showing a preferred embodiment of an image forming machine constructed according to the present invention.

FIG. 1 is a schematic block diagram showing an embodiment of an image forming machine to which the present invention is applied, and FIG. 2 is a fragmentary view of the image forming machine showing a transfer device equipped in the image forming machine of FIG. 1 is a front view, FIG. 3 is a schematic perspective view of a transfer sheet supply driving means equipped in the image forming machine of FIG. 1, and FIG. 4 is a transfer belt driving means and transfer roller and discharge roller driving equipped in the image forming machine of FIG. It is a schematic perspective view of a means.

An image forming machine 2 to which the present invention shown in FIG. 1 is applied.
Includes a photosensitive drum 3 that is rotatably mounted. The photoconductor drum 3 is rotationally driven in the direction of arrow A by a photoconductor drum driving means described later. Around the photosensitive drum 3, as viewed in the direction of rotation indicated by arrow A, a charging corona discharger 4, a developing device 5, a transfer device 6,
A cleaning unit 8 and a discharge lamp 9 are provided. The image forming machine 2 shown in the figure has an irradiation lamp 10, a first mirror 11, and a lamp arranged above the photosensitive drum 3.
An optical system including a second mirror 12, a third mirror 13, a lens 14, and a fourth mirror 15 is provided. This optical system irradiates an original placed on an original placing transparent plate (not shown) with an illumination lamp 10, and a reflected light image thereof is reflected by a first mirror 11, a second mirror 12, a third mirror 13, and a lens. An image is formed on the outer peripheral surface of the photoconductor drum 3 via 14 and the fourth mirror 15. The image forming machine 2 includes a transfer paper supply device 16 for supplying the transfer paper to the transfer device 6. The transfer sheet supply device 16 includes a transfer sheet cassette 17 for storing transfer sheets, a transfer sheet delivery roller 18, a separation roller pair 19, a guide path 20, a conveyance roller pair 21, a guide path 22, and a registration roller pair 23. There is. On the upstream side of the registration roller pair 23,
A transfer sheet detecting means SW1 for detecting the leading end of the transfer sheet conveyed to the guide path 22 is provided. The above-mentioned rollers of the transfer paper supply device 16 configured in this manner are rotationally driven in the directions indicated by arrows by transfer paper supply roller driving means described later. Further, a fixing roller pair 24 and a discharge roller pair 25 are provided on the transfer paper delivery side of the transfer device 6, and these rollers are rotationally driven in the directions indicated by arrows by drive means described later.

The image forming machine 2 configured as described above is
While the photoconductor drum 3 is driven to rotate in the direction of arrow A, the charging corona discharger 4 charges the photoconductor on the photoconductor drum 3 substantially uniformly to a specific polarity, and then is not illustrated by the irradiation lamp 10. The original placed on the original placing transparent plate is irradiated and the reflected light image thereof is reflected by the first mirror 11, the second mirror 12, the third mirror 13, the lens 14 and the fourth mirror.
The photosensitive drum 3 is scanned and exposed through the mirror 15 to form an electrostatic latent image on the photosensitive drum 3. After that, the electrostatic latent image on the photosensitive drum 3 is developed into a toner image by the developing device 5. On the other hand, the transfer paper stored in the transfer paper cassette 17 of the transfer paper supply device 16 is sent out from the transfer paper delivery roller 18, and the separation roller pair 19, the guide path 20, the conveying roller pair 21, the guide path 22 and the registration roller pair 23 are provided. And transferred to the transfer device 6. The transfer paper conveyed to the transfer device 6 is transferred between the photoconductor drum 3 on which the toner image is formed and a transfer belt of the transfer device 6, which will be described later, so that the toner image is transferred and then fixed by the fixing roller pair 24. Then, it is discharged from the discharge roller pair 25. Further, the cleaning unit 8 removes the toner adhering to the outer peripheral surface of the photoconductor drum 3 which has undergone the transfer process as described above, and further, the charge removal lamp 9 irradiates the photoconductor surface with the charge removal light. , The electricity is removed.

Next, the transfer device 6 will be described with reference to FIG. The illustrated transfer device 6 includes a transfer belt unit 60 and a unit housing 70 that houses and supports the transfer belt unit 60.

The transfer belt unit 60 comprises a support frame 61 and support plates 62, 62 fixed to the front and rear ends of the support frame 61 (in FIG. 2, the support plate 62 on the rear end side). Only shown). A drive roller 63 is arranged on the front support plate 62 and the rear support plate 62. The drive roller 63 is formed of a hollow material made of an aluminum alloy, and a rotary shaft 631 is attached to the front end and the rear end thereof.

The drive roller 63 is mounted on the support plate 62.
And a transfer roller 65 disposed between the driving roller 63 and the drive roller 64, and a transfer roller 65 disposed between the transfer roller 65 and the drive roller 64. The tension roller 66 provided and the earth roller 52 provided between the transfer roller 65 and the drive roller 63 are provided. The driven roller 49 is made of a columnar material made of an aluminum alloy, has rotary shafts formed at both ends thereof, and is rotatably supported by the support plate 62. The transfer roller 65 includes a rotating shaft 651 formed of a cylindrical material made of steel, and a sponge-like roller portion 652 mounted on the outer peripheral surface of the rotating shaft 651 with a conductive adhesive. 651 is rotatably supported by the support plate 62. Roller part 652
Is formed by impregnating a roll member formed of foam such as urethane foam or silicon foam with a conductive substance such as carbon and having a volume electric resistance value of 10 ² to
It is set to 10 ⁹ Ωcm. The transfer roller 65
The rotary shaft 651 is configured such that a predetermined voltage is applied at a predetermined timing by the voltage applying means 200 shown in FIG. The tension roller 66 is made of a columnar material made of an aluminum alloy, has rotary shafts formed at both ends thereof, and is rotatably supported by the support plate 62. Like the tension roller 66, the earth roller 67 is also made of a columnar material made of an aluminum alloy, and has rotary shafts formed at both ends thereof.
It is rotatably supported by 2 and is body-grounded by an appropriate earthing means.

An endless transfer belt 68 is wound around the drive roller 63, the driven roller 64, the transfer roller 65, the tension roller 66 and the earth roller 67 mounted on the support plate 62 as described above. The transfer belt 68 is made of a semiconductive material such as polychloroprene and has a volume electric resistance value of 10 ⁹ to 10 ^9.
It is set to ¹² Ωcm.

Next, the unit housing 70 for accommodating and supporting the transfer belt unit 60 will be described. The unit housing 70 in the illustrated embodiment has a front side wall (not shown), a rear side wall 71, a bottom wall 72, a left side wall 73 and a right side wall 74, and the upper side is open. It is integrally formed. Above the left and right side walls 73 of the front and rear side walls 71, a bearing mounting portion 621 provided on a support plate 62 that pivotally supports a rotation shaft 631 of the drive roller 63 of the transfer belt unit 60 is rotatably supported. A circular support hole 711 is formed. The bearing mounting portion 6 provided on the support plate 62 in the circular support hole 711.
21 is fitted, the transfer belt unit 60 is supported so as to be rotatable around the bearing mounting portion 621. The bottom wall 72 is provided with a sliding rail 721 that is formed so as to project downward and extends from the front end to the rear end. An opening 722 is formed in the center of the bottom wall 72.

Left side wall 73 of the unit housing 70
On the side, a waste toner storage portion 75 is formed in the front-rear direction along the left side wall 73. A toner conveying member 76 is arranged below the waste toner container 75. The toner conveying member 76 includes a rotating shaft 761 and a spiral blade 762 attached to the rotating shaft 761, and the rotating shaft 761 is transmission-coupled to a driving device (not shown).

In the unit housing 70, the transfer belt unit 60 is arranged along the waste toner container 76.
Means 8 for cleaning the transfer belt 68 of
0 is set. The cleaning means 80 in the illustrated embodiment includes a holder 81 and a cleaning blade 8.
2 and a paper dust removing member 83. Holder 81
Is a channel-shaped member having a length substantially the same as the width of the transfer belt 68, and includes a mounting portion 811 and a supporting portion 812. Support part 812 of the holder 81
A mounting member 84 is fixed to the central portion of the. The mounting member 84 is provided with a hole 841 having a circular cross section, which is formed at a base portion of the mounting member 84 and penetrates in the longitudinal direction and has an opening 842 in a part thereof.
3 is integrally formed. A support shaft 85 for rotatably supporting the mounting member 84 is provided on the bottom wall 72 of the unit housing 70. The support shaft 85
Has two parallel surfaces corresponding to the diameter of the hole 841 and corresponding to the opening width of the opening 842 on the outer periphery. To attach the mounting member 84 to the support shaft 85, the opening 842 is made to correspond to two parallel surfaces formed on the support shaft 85, and the hole 841 is fitted into the support shaft 85 from above,
By pivoting the mounting member 84 by approximately 90 °, the actuated lever 843 is positioned so as to project from the opening 722 formed in the bottom wall 73 as shown in the figure. The cleaning blade 82 is made of urethane rubber or the like and has a length approximately the same as the width of the transfer belt 68, and is fixed to the mounting portion 811 of the holder 81 by an adhesive or the like. The edge of the cleaning blade 82 is pressed against the surface of the transfer belt 68 as shown in the figure during transfer, and scrapes off the toner adhering to the transfer belt 68. The paper dust removing member 83 is made of a foam material such as sponge, and has a length substantially the same as the width of the transfer belt 68 like the cleaning blade 82, and an adhesive agent or the like is attached to the mounting portion 811 of the holder 81. Is stuck by. The paper dust removing member 83 is arranged downstream of the cleaning blade 82 in the operating direction of the transfer belt 68. The paper dust removing member 83 has a function of removing the paper dust attached to the transfer belt 68, which is difficult to remove with the cleaning blade 82. A seal plate 77 is mounted on the upper end of the left side wall 73 of the unit housing 70 so as to cover the waste toner container 75. The seal plate 77 extends from the front side wall to the rear side wall 71.

The unit housing 70 constructed as described above is mounted on the slider 101 mounted on the body housing 100 with the slide rail 721 formed on the bottom wall 72 and positioned at a predetermined position. After that, it is fixed to the machine housing 100 by fixing means (not shown). The machine housing 100 is provided with a contacting / separating means 110 for rotating the transfer belt unit 60 upward about a bearing mounting portion 621 to press the transfer belt 68 against the photosensitive drum 3. Contact / separation means 11
Reference numeral 0 has a solenoid SOL which is a drive source.
The plunger 112 of the solenoid SOL is connected by a connecting pin 115 to the other end of a lever 114, one end of which is attached to an operating shaft 113 rotatably supported by a front plate and a rear plate (not shown) that form the housing 100. It is connected. One end of a contacting / separating operating lever 116 formed of spring steel is attached to each end of the operating shaft 113 (in FIG. 2, the contacting / separating operating lever 11 on the rear end side is mounted).
Only 6 is shown). This operating lever 116 for contact and separation
The other end of the transfer belt unit 60 is disposed at a position facing the lower surfaces of the support plates 62, 62 of the transfer belt unit 60 through openings (not shown) formed at the front and rear ends of the bottom wall 72 of the unit housing 70. Has been done. Further, a cleaning operation lever 117 made of spring steel is attached to the central portion of the operation shaft 113 so as to come into contact with the upper surface of the operated lever 843 formed on the mounting member 84 of the cleaning means 80. The actuated lever 843, the cleaning actuating lever 117, the actuating shaft 110, the lever 114, and the like are arranged such that the holder 81 on which the cleaning blade 83 and the paper dust removing member 83 are mounted is moved in the operating direction of the transfer belt unit 60 by the contacting / separating means. A corresponding actuating mechanism is configured to be actuated by a solenoid SOL which is a drive source common to the contacting / separating means. A return spring 118 is provided between the lever 114 and the housing 100. Therefore, when the solenoid SOL is deenergized, the lever 114 is shown by a two-dot chain line in FIG. 2 due to the spring force of the return spring 118. It is located in the non-transfer position.

The operation of the contacting / separating means 110 configured as described above will be described. As shown in FIG. 2, the solenoid S
When OL is urged and the plunger 112 is actuated to the right in the figure, the lever 114 causes the actuating shaft 113 to rotate counterclockwise in the figure. Therefore, the contact / separation actuating lever 116 is swung upward around the actuating shaft 113, and the transfer belt unit 60 is swung upward around the driving roller 63 by the swing of the approach / separating actuating lever 116. The transfer belt 68 is pushed up and positioned at the transfer position where the transfer belt 68 is pressed against the outer peripheral surface of the photosensitive drum 3. on the other hand,
The cleaning actuating lever 117 mounted on the actuating shaft 110 is swung downward, so that the mounting member 84 having the actuated lever 843 in contact with the actuating lever 117 is centered on the support shaft 85. At 2, it is rotated clockwise. As a result, the holder 81 to which the mounting member 84 is attached operates at the position shown in FIG. 2, and the edge portion of the cleaning blade 82 attached to the holder 81 is pressed against the transfer belt 68. In addition, the paper dust removing member 83 attached to the holder 81 in this state
Are brought into contact with the transfer belt 68. When the solenoid SOL is deenergized and the return spring 118 positions the lever 114 at the position indicated by the chain double-dashed line in FIG. 2, the actuating shaft 113 is rotated clockwise in FIG. Therefore, as shown by the chain double-dashed line in FIG. 2, the contact / separation actuating lever 116 mounted on the actuating shaft 113 is swung downward, and the transfer belt unit 60 is swung downward about the drive roller 63 by its own weight. The lower surface of the support plate 62 is the bottom wall 72 of the unit housing 70.
To stop and come to a state of the non-transfer position shown by the chain double-dashed line in FIG. On the other hand, the cleaning actuating lever 117 mounted on the actuating shaft 113 is swung upward, so that the mounting member 84 having the actuated lever 843 in contact with the actuating lever 117 is centered on the support shaft 85. 2 is rotated counterclockwise in FIG.
As a result, the holder 81 to which the mounting member 84 is attached operates at the position shown by the chain double-dashed line in FIG.
The cleaning blade 82 attached to the No. 1 is separated from the transfer belt 68.

Next, the drum driving means for rotating the photosensitive drum 3 will be described with reference to FIG. The photosensitive drum driving means 30 in the illustrated embodiment includes an electric motor M1 which is a driving source. A drive toothed pulley 302 is attached to a drive shaft 301 of the electric motor M1, and a timing belt is attached to the drive toothed pulley 302 and a drum drive toothed pulley 303 attached to the rear end of the photosensitive drum 3. 304 is wound. Therefore, when the drive shaft 31 of the electric motor M1 rotates in the arrow D1 direction, the photosensitive drum 3 is rotationally driven in the arrow A direction via the drive toothed pulley 302, the timing belt 304, and the drum drive toothed pulley 303. The electric motor M1 is equipped with a rotary encoder RE1 for detecting the rotation speed of the drive shaft 301, and the rotary encoder RE1 sends a detection signal to a control means described later. The rotary encoder RE1 functions as speed detecting means for detecting the peripheral speed of the photosensitive drum 3.

A transfer paper supply roller driving means for rotating and driving the respective rollers of the transfer paper supply device 16 will be described with reference to FIG.
Will be described with reference to. The transfer paper supply roller driving means 40 in the illustrated embodiment includes an electric motor M2 which is a drive source. A drive toothed pulley 402 is mounted on a drive shaft 401 of the electric motor M2. A roller drive gear 403 is attached to a rotary shaft 181 of the transfer paper feed roller 18 which constitutes the transfer paper supply device 16 via an electromagnetic clutch CL1. Pair of the above-mentioned judgment rollers 1
A roller drive gear 404 is mounted on a rotary shaft 181 of a drive roller 190 that constitutes one of the nine rollers. A transmission gear 405 that meshes with both roller drive gears 403 and 404 is rotatably supported by a machine body housing (not shown). A toothed pulley 406 is integrally formed on the side surface of the transmission gear 405. A drive roller 210 that constitutes one roller of the pair of transport rollers 21.
A roller driving gear 407 is mounted on the rotating shaft 211 of the above through an electromagnetic clutch CL2. A transmission gear 408 meshing with the roller drive gear 407 is rotatably supported by a machine body housing (not shown). This transmission gear 4
A toothed pulley 409 is integrally formed on the side surface of 08. A roller drive gear 410 is attached to a rotary shaft 231 of a drive roller 230 that constitutes one of the registration roller pair 23 via an electromagnetic clutch CL3. The roller drive gear 410 is transmission-coupled to the transmission gear 408 via an intermediate gear 411 and an intermediate gear 412 that are rotatably supported by a body housing (not shown). Drive toothed pulley 402 and toothed pulley 406 mounted on the drive shaft 401 of the electric motor M2
The timing belt 413 is wound around the toothed pulley 409. In the figure, 414 and 415 are the intermediate portion between the toothed pulley 406 and the toothed pulley 409, and the drive toothed pulley 402 and the toothed pulley 409.
It is a tension pulley that presses the timing belt 412 at an intermediate portion between and. Therefore, the electric motor M
When the second drive shaft 401 rotates in the direction of arrow D2, each of the rollers is rotated in the direction indicated by the arrow.

Next, a transfer belt driving means for driving the transfer belt 68 of the transfer belt unit 60 will be described with reference to FIG. The transfer belt drive means 50 in the illustrated embodiment is an electric motor M3 that is a drive source.
Is provided. A drive toothed pulley 502 is mounted on a drive shaft 501 of the electric motor M3. on the other hand,
A roller drive gear 503 is mounted on the rotary shaft 631 of the drive roller 63. The roller drive gear 94 meshes with a transmission gear 504 which is rotatably supported by a body housing (not shown). A toothed pulley 505 is integrally formed on the side surface of the transmission gear 504. The toothed pulley 505 and the drive shaft 5 of the electric motor M3.
Drive toothed pulley 502 mounted on 01 and a transmission gear 5 rotatably supported by a machine body housing (not shown).
A timing belt 508 is wound around a toothed pulley 507 integrally formed on the side surface of 06. In the figure, reference numeral 509 denotes a drive toothed pulley 502 and a toothed pulley 507.
It is a tension pulley that presses the timing belt 508 at an intermediate portion between and. Therefore, when the drive shaft 501 of the electric motor M3 rotates in the direction of the arrow D3, the drive roller 63 is rotated in the direction indicated by the arrow and the transfer belt 68.
Is operated in the direction of arrow B. The electric motor M
A rotary encoder RE3 for detecting the rotation speed of the drive shaft 501 is attached to the rotary shaft 3, and the rotary encoder RE3 sends a detection signal to a control means described later. This rotary encoder RE3 is provided with an arrow B on the transfer belt 68.
It functions as speed detecting means for detecting the moving speed in the direction. The transfer belt driving means 50 also functions as a driving means for driving the fixing roller pair 24 and the discharge roller pair 25. A roller drive gear 510 is mounted on a rotary shaft 241 of a drive roller 240 that constitutes one roller of the fixing roller pair 24.
Reference numeral 10 is transmission-coupled to the transmission gear 504 through an intermediate gear 511 and an intermediate gear 512 which are rotatably supported by a machine housing (not shown). A drive toothed pulley 513 is attached to the rotary shaft 251 of the drive roller 250 that constitutes one of the discharge roller pair 25. On the other hand, the transmission gear 51 that meshes with the transmission gear 506.
4 is rotatably supported by a body housing (not shown), and a timing belt 515 is wound around a toothed pulley 515 integrally formed on the side surface of the transmission gear 514 and the drive toothed pulley 513. . Therefore, when the drive shaft 501 of the electric motor M3 rotates in the direction of arrow D3,
The fixing roller pair 24 and the discharge roller pair 25 are rotationally driven in the directions indicated by arrows.

The image forming machine 2 is equipped with the control means 550 shown in FIG. The control means 550 is composed of a microcomputer, and has a central processing unit (CPU) 551 that performs arithmetic processing according to a control program,
Read only memory (RO
M) 552, a readable / writable random access memory (RAM) 553 for storing calculation results, and a timer 55
4 and an input / output interface (I / O) 555. The control means 550 includes the transfer paper detection means SW1, the copy start switch SW2, and the electric motor M1.
And rotary encoder R for detecting the rotation speed of M3
The electric motors M1, M2, M3, the electromagnetic clutches CL1, CL are input with signals from E1 and RE3, etc.
2, the solenoid SOL and the voltage applying means 20
The control signal is output to 0 or the like. The control means 250
Also controls the operation of the charging corona discharger 4, the developing device 5, the cleaning unit 7, the discharge lamp 8, the irradiation lamp 9 and the like.

The image forming machine according to the present invention is configured as described above, and one embodiment of the operation from when the copying start switch SW2 is turned on to when the copying operation is started will be described with reference to the flowchart shown in FIG. Explain. The control means 550 checks whether or not the copy start switch SW2 has been turned on and turned on (step S1). When the copy start switch SW2 is turned on, the control means 55
0 advances to step S2 to drive the electric motors M1, M2 and M3. After driving the electric motors M1, M2 and M3 in step S2, the control means 550 proceeds to step S3 to check whether or not the flag is cleared. Here, first, the case where the flag is not cleared will be described. If the flag is not cleared in step S3, the control means 550 proceeds to step S4 to execute the primary paper feeding operation, and energizes the electromagnetic clutches CL1 and CL2. When the electromagnetic clutches CL1 and CL2 are urged, the transfer paper feed roller 18 and the drive roller 210, which constitutes one of the pair of conveyance rollers 21, are rotationally driven.
Transfer paper cassette 17 The top transfer paper placed on the transfer paper cassette 17 is sent out by the transfer paper sending roller 18, and the paper feed roller pair 19 (the separation roller pair 19 does not have an electromagnetic clutch attached, so the electric motor M2 is driven). At the same time, it is rotationally driven) and is conveyed toward the registration roller pair 23 by the conveyance roller pair 21. After energizing the electromagnetic clutches CL1 and CL2 in this way, the control means 550 proceeds to step S5 to check whether or not the transfer paper detection means SW1 arranged upstream of the registration roller pair 23 is turned on. . If the transfer sheet detecting unit SW1 is not turned on, the transfer sheet has not reached the transfer sheet detecting unit SW1, and therefore the process proceeds to step S9 described later. Step S5
If the transfer paper detecting means SW1 is turned on at, it is judged that the transfer paper has reached the transfer paper detecting means SW1, and the control means 550 sets the timer (T) 254 to T1 (step S6). The set time T1 is a time required for the leading edge of the transfer sheet to reach the registration roller pair 23 after passing the transfer sheet detection means SW1, and is set to, for example, 0.1 second. Next, the control means 550
Is the elapsed time T from when the transfer sheet detecting means SW1 is turned on.
It is checked whether S has reached the set time T1 (step S7). Then, if the elapsed time TS has not reached the set time T1, step S9 described later is performed.
If the elapsed time TS has reached the set time T1, the control means 550 proceeds to step S8 to deactivate the electromagnetic clutches CL1 and CL2 to move the transfer paper feed roller 18 and the transport roller pair 21. Stop. At this time, the leading edge of the transfer sheet is nipped by the pair of registration rollers 23, and the primary sheet feeding operation ends. Then, the control means 550 proceeds to step S9 to clear the flag, and further proceeds to step S13. Step S
In 13, the control means 550 checks whether or not the primary paper feeding operation is completed and the solenoid SOL is turned on. This time, the primary paper feeding is completed, but the solenoid SOL is not turned on, so the control means 550 returns to the step S3.

Next, the case where the flag is cleared in step S3 will be described. Step S3
If the flag is cleared in step S10, the control means 550 proceeds to step S10 to check whether the peripheral speed DV of the photosensitive drum 3 and the moving speed BV of the transfer belt 68 are equal. The peripheral speed DV of the photosensitive drum 3 and the moving speed BV of the transfer belt 68 are controlled by the control means 55.
0 is calculated based on the detection signals from the rotary encoders RE1 and RE3 that detect the rotation speeds of the electric motors M1 and M3. Peripheral speed DV of the photosensitive drum 3
Can be obtained on the basis of the reduction ratio based on the number of teeth of the drive toothed pulley 302 and the number of teeth of the drum drive toothed pulley 303, the outer diameter of the photosensitive drum 3, and the rotation speed signal from the rotary encoder RE1. it can. Also,
The moving speed BV of the transfer belt 68 is determined by the number of teeth of the drive toothed pulley 502, the number of teeth of the toothed pulley 505, the number of teeth of the transmission gear 504, and the number of teeth of the roller drive gear 503, and It can be obtained based on the outer diameter of the drive roller 63 and the rotation speed signal from the rotary encoder RE3. Copy start switch SW
Immediately after 2 is turned on and the electric motors M1 and M3 are driven, the rotational speeds of both motors rarely match, and therefore the peripheral speed DV of the photosensitive drum 3 and the moving speed BV of the transfer belt 68 are normally set. Is not equal to
Proceed to 12 to set the flag. In addition, although rarely, in step S10, the peripheral speed DV of the photosensitive drum 3 is
And the moving speed BV of the transfer belt 68 are equal to each other, even if the transfer belt unit 60 is moved to the transfer position and the transfer belt 68 is pressed against the photoconductor drum 3, the above problem does not occur. In order to move the belt unit 60 to the transfer position, the process proceeds to step S11 to energize the solenoid SOL. If the solenoid SOL is energized in step S11, the control means 550 determines in step S11.
In step 12, a flag is set, and the flow advances to step S13 to check whether or not the primary sheet feeding operation is completed and the solenoid SOL is turned on. In this case, since the primary paper feeding is not performed in any case, the control means 550
Returns to step S3 and checks whether the flag is cleared. This time, since the flag has been set in step S12, step S4
Through step S9, the primary sheet feeding operation is executed. As described above, even if the flag is cleared first, most of them perform the primary sheet feeding operation before moving the transfer belt unit 60 to the transfer position. When the primary paper feeding operation is executed as described above, the control means 550
In step S13, it is checked whether or not the primary sheet feeding operation is completed and the solenoid SOL is turned on. Even if steps S10 to S12 are first performed from step S3 as described above, most of them perform the primary sheet feeding operation before moving the transfer belt unit 60 to the transfer position as described above. Therefore, the solenoid SOL is not turned on, and the control means 550 returns to step S3. In addition, like this time, the above step S
3 is first executed from step S10 to step S12, and rarely the peripheral speed DV of the photosensitive drum 3 and the transfer belt 68
When the transfer belt unit 60 is moved to the transfer position, the solenoid SOL is turned on. Therefore, when the primary sheet feeding operation of steps S4 to S9 is completed, the control means 550 controls the step S14. Proceed to and execute the copy operation.

When the primary sheet feeding operation is completed as described above and the process proceeds to step S3 again, the control means 550 checks whether or not the flag is cleared, but this time, the flag is cleared in step S9. Therefore, the process proceeds to step S10, and it is checked whether the peripheral speed DV of the photosensitive drum 3 and the moving speed BV of the transfer belt 68 are equal. In step S10, the peripheral speed DV of the photosensitive drum 3 and the moving speed B of the transfer belt 68 are set.
If V is not equal, the process proceeds to step S12, which will be described later, and the peripheral speed DV of the photosensitive drum 3 and the transfer belt 68 are
If the moving speeds BV of the two match, the above problem does not occur even if the transfer belt unit 60 is moved to the transfer position and the transfer belt 68 is pressed against the photosensitive drum 3, so the control means 550 proceeds to step S11. Energize the solenoid SOL. When the solenoid SOL is energized, the plunger 112 is operated to the right in the figure as described above, and the contact / separation operating lever 11 is operated via the lever 114 and the operating shaft 113.
Since 6 is swung upward around the operating shaft 113,
The transfer belt unit 60 is rotated upward about the drive roller 63 and is positioned at the transfer position where the transfer belt 68 is pressed against the image carrier 3. In this way, when the transfer belt unit 60 is positioned at the transfer position,
The control means 550 sets a flag in step S12, proceeds to step S13, and ends the primary paper feeding operation.
Moreover, it is checked whether or not the solenoid SOL is turned on. This time, the primary sheet feeding is completed as described above, the solenoid SOL is also turned on in step S11 and the transfer belt unit 60 is positioned at the transfer position, so the control means 550 proceeds to step S14 to execute the copying operation. To do.

Next, another embodiment of the present invention will be described with reference to the flowchart shown in FIG. Control means 55
0 checks whether or not the copy start switch SW2 is turned on and turned on (step P1). If the copy start switch SW2 is turned on, the process proceeds to step P2 to drive the electric motors M1, M2 and M3. With
The timer (T) 254 is set to T2. The set time T2 is a time required for the electric motors M1 and M2 to reach a specified rotational speed and for the peripheral speed DV of the photosensitive drum 3 and the moving speed BV of the transfer belt 68 to coincide with each other. It is set to 1.0 to 2.0 seconds. When the electric motors M1, M2 and M3 are driven and the timer (T) 254 is set to T2 in step P2, the control means 550 proceeds to step P3 to check whether the flag is cleared or not. If the flag is not cleared, the control means 550 executes steps P4 to P9 similar to the primary sheet feeding operation of steps S4 to S9 in the embodiment shown in FIG. 6, and shifts to step P13. To do. In step P13, the control means 550 checks whether or not the primary sheet feeding operation is completed and the solenoid SOL is turned on, as in step S13 of the embodiment shown in FIG. This time, the primary paper feeding is completed, but the solenoid S
Since the OL is not turned on, the control means 550 returns to step P3.

Next, the case where the flag is cleared in step P3 will be described. Step P3
If the flag is cleared at, the control means 550 proceeds to step P10 and the elapsed time TS after driving the electric motors M1 and M2 is the set time T.
Check if 2 has been reached. When the process directly proceeds from step P3 to step P10, the elapsed time TS after driving the electric motors M1 and M2 is the set time T
2 has not been reached, the control means 550 uses the step P1.
In step P13, the flag is set, and in step P13, it is checked whether the primary sheet feeding operation is completed and the solenoid SOL is turned on. Since the primary paper feeding is not performed anyway this time, the control means 550 returns to step P3 to check whether the flag is cleared or not. Since the flag has been set in step P12 this time, the primary sheet feeding operation of steps P4 to P9 is executed. In this way, even when the flag is cleared first, the primary sheet feeding operation is executed before the transfer belt unit 60 is moved to the transfer position. When the primary sheet feeding operation is executed as described above, the control means 550 checks in step P13 whether the primary sheet feeding operation is completed and the solenoid SOL is turned on. Even if steps P10 to P12 are first executed from step P3 as described above, the primary sheet feeding operation is executed before the transfer belt unit 60 is moved to the transfer position as described above, so the solenoid is used. The SOL is not turned on, and the control means 550 returns to step P3.

When the primary sheet feeding operation is completed as described above and the process moves to step P3 again, the control means 550 checks whether or not the flag is cleared, but this time, the flag is cleared in step P9. Therefore, the process proceeds to step P10, and it is checked whether the elapsed time TS after driving the electric motors M1 and M2 has reached the set time T2. In step P10, when the elapsed time TS after driving the electric motors M1 and M2 has not reached the set time T2, the process proceeds to step P12 described later, and the elapsed time after driving the electric motors M1 and M2. When TS reaches the set time T2, the control means 550 causes the electric motors M1 and M2 to reach the specified rotation speed so that the peripheral speed DV of the photosensitive drum 3 and the moving speed BV of the transfer belt 68 match. Then, the process proceeds to step P11 to energize the solenoid SOL. When the solenoid SOL is energized, the plunger 112 is actuated to the right in the figure as described above, and the contact / separation actuation lever 116 is actuated via the lever 114 and actuation shaft 113.
Is oscillated upward about the operating shaft 113, the transfer belt unit 60 is rotated upward about the drive roller 63, and the transfer belt 68 is positioned at the transfer position where the transfer belt 68 is pressed against the image carrier 3. In this way, when the transfer belt unit 60 is positioned at the transfer position, the control means 550 sets a flag in step P12, the process proceeds to step P13, the primary sheet feeding operation is completed, and the solenoid SOL is turned on. Check if there is. This time, the primary paper feeding has finished as above,
Since the solenoid SOL is also turned on in step P11 and the transfer belt unit 60 is positioned at the transfer position, the control means 550 proceeds to step P14 and executes the copying operation.

[0037]

The transfer device of the image forming machine according to the present invention is configured as described above, and according to the first invention, drive control of the photosensitive drum drive means and the transfer belt drive means based on the image formation start signal. In addition, based on the detection signals from the first speed detecting means and the second speed detecting means,
When the peripheral speed of the photoconductor drum and the moving speed of the transfer belt match, the contact / separation means is operated to move the transfer belt unit to the transfer position, so when the transfer belt is pressed against the photoconductor drum, Since there is no speed difference between the peripheral speed of the body drum and the moving speed of the transfer belt, it is possible to prevent the surface of the photosensitive drum from being scraped or the damage to the drum due to the speed difference between the two. Also,
According to the present invention, when the transfer belt is pressed against the photosensitive drum as described above, there is no speed difference between the peripheral speed of the photosensitive drum and the moving speed of the transfer belt. The load on both motors will not increase. Further, according to the present invention, since the transfer belt is pressed against the photoconductor drum as described above after the moving speed of the transfer belt and the peripheral speed of the photoconductor drum coincide with each other, it is possible to drive both of them. The motor reaches the specified speed in a short time, and thus the image forming time can be shortened.

Further, according to the second aspect of the invention, until the peripheral speed of the photosensitive drum and the moving speed of the transfer belt match as described above, the transfer belt unit is operated to the transfer position. In the meantime, since the transfer paper supply roller driving means is drive-controlled to execute the primary paper feeding operation of transporting the transfer paper to the position immediately before the transfer belt unit, the image forming time can be shortened.

Further, according to the third invention, the photosensitive drum driving means and the transfer belt driving means are driven and controlled based on the image formation start signal, and the photosensitive drum driving means and the transfer belt driving means are driven. Since the contact / separation unit is controlled to operate to move the transfer belt unit to the transfer position after a predetermined time has elapsed, the photosensitive drum driving unit and the transfer belt driving unit are regulated when the transfer belt is pressed against the photosensitive drum. And the peripheral speed of the photosensitive drum and the moving speed of the transfer belt match. Therefore, the above-mentioned inconvenience caused by the speed difference between the two is eliminated, and the same effect as the first aspect of the invention can be obtained.

Further, according to the fourth aspect of the invention, after the photosensitive drum drive means and the transfer belt drive means are driven as described above, the contact / separation means is operated and controlled to transfer the transfer belt unit after a predetermined time has elapsed. The image forming time is shortened because the transfer sheet supply roller driving means is controlled to drive the transfer sheet to the position immediately before the transfer belt unit before the sheet is moved to the position. be able to.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an image forming machine to which the present invention is applied.

FIG. 2 is a front view of a main part of the image forming machine showing a transfer device equipped in the image forming machine of FIG.

FIG. 3 is a schematic perspective view of a transfer sheet supply driving unit equipped in the image forming apparatus of FIG.

FIG. 4 is a schematic perspective view of a transfer belt driving unit, a transfer roller and a discharge roller driving unit which are provided in the image forming apparatus of FIG.

5 is a schematic block diagram of a control unit equipped in the image forming apparatus of FIG.

FIG. 6 is a flowchart showing an embodiment of the operation of the control means of FIG.

7 is a flowchart showing another embodiment of the operation of the control means of FIG.

[Explanation of symbols]

 2: Image forming machine 3: Image carrier 4: Charging corona discharger 5: Developing device 6: Transfer device 8: Cleaning unit 9: Static elimination lamp 10: Irradiation lamp 11: First mirror 12: Second mirror 13 : Third mirror 14: Lens 15: Fourth mirror 16: Transfer paper feeding device 17: Transfer paper cassette 18: Transfer paper sending roller 19: Separation roller pair 20: Guide path 21: Conveying roller pair 22: Guide path 23 : Registration roller pair 30: Photosensitive drum drive device 40: Transfer paper supply roller drive means 50: Transfer belt drive means 60: Transfer belt unit 61: Support frame 62: Support plate 63: Drive roller 64: Driven roller 65: Transfer roller 66: Tension roller 67: Earth roller 68: Transfer belt 70: Unit housing 75: Waste toner storage section 76 Toner conveying member 80: Cleaning means 100: Machine housing 101: Slider 110: Contact / separation means 113: Operating shaft 114: Lever 116: Contact / separation operating lever 117: Cleaning operation lever 200: Voltage applying means 301: Electric motor M1 Drive shaft 302: Drive toothed pulley 303: Drum drive toothed pulley 304: Timing belt 401: Electric motor M2 drive shaft 402: Drive toothed pulley 403: Roller drive gear 404: Roller drive gear 405: Transmission gear 406: Tooth Pulley 407: Roller drive gear 408: Transmission gear 409: Toothed pulley 410: Roller drive gear 411: Intermediate gear 412: Intermediate gear 413: Timing belt 414: Tension pulley 415: Tension pulley 501: Electric motor M3 Drive shaft 502: Drive toothed pulley 503: Roller drive gear 504: Transmission gear 505: Toothed pulley 506: Transmission gear 507: Toothed pulley 508: Timing belt 509: Tension pulley 510: Roller drive gear 511: Intermediate gear 512 : Intermediate gear 513: Drive toothed pulley 514: Transmission gear 515: Toothed pulley 516: Timing belt 550: Control means 551: Central processing unit (CPU) 552: Read only memory (ROM) 553: Random access memory (RAM) 554: Timer 555: Input / output interface 621: Bearing mounting portion 631: Driving roller rotation shaft 651: Transfer roller rotation shaft 652: Transfer roller roller portion 721: Sliding rail 843: Actuated lever M1: Electric motor M2: Electric motor M3: Electric motor CL1: Electromagnetic clutch CL2: Electromagnetic clutch CL3: Electromagnetic clutch RE1: Rotary encoder RE2: Rotary encoder RE3: Rotary encoder SW1: Transfer paper detection means SW2: Copy start switch

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Rio Uchida 1-2-2 Tamatsukuri, Chuo-ku, Osaka Mita Engineering Co., Ltd. (72) Yuzuru Nanjo 1-2-2 Tamatsukuri, Chuo-ku, Osaka Mita Within Kogyo Co., Ltd. (72) Inventor, Yuki Ito 1-22 Takumazo, Chuo-ku, Osaka Mita Kogyo Co., Ltd.

Claims (4)

[Claims] 1. A photosensitive drum on the outer peripheral surface of which a toner image is formed, a driving roller, a driving roller arranged at a distance from the driving roller, and a driving roller and the driving roller. And a transfer belt unit having a transfer belt arranged to face the photoconductor drum, a contacting / separating means for operating the transfer belt unit to a transfer position and a non-transfer position, and a rotary drive for the photoconductor drum. Photoconductor drum drive means, transfer belt drive means for operating the transfer belt, first speed detection means for detecting the peripheral speed of the photoconductor drum, and second speed for detecting the moving speed of the transfer belt. And a driving means for controlling the photosensitive drum driving means and the transfer belt driving means based on the image forming start signal, and the first speed detecting means and the second speed detecting means. Control means for actuating and controlling the contacting / separating means to actuate the transfer belt unit to the transfer position when the peripheral speed of the photosensitive drum and the moving speed of the transfer belt match based on the detection signal. Image forming machine characterized by. 2. A photosensitive drum on the outer peripheral surface of which a toner image is formed, a drive roller, a driving roller arranged at a distance from the driving roller, and a driving roller and the driving roller. And a transfer belt unit having a transfer belt disposed so as to face the photoconductor drum, a contacting / separating unit that operates the transfer belt unit to a transfer position and a non-transfer position, the photoconductor drum and the transfer belt. A transfer paper supply device for supplying a transfer paper between the unit, a photosensitive drum driving means for rotating the photosensitive drum, a transfer belt drive means for operating the transfer belt, and a drive for the transfer paper supply device. The transfer paper supply roller driving means for urging, the first speed detecting means for detecting the peripheral speed of the photosensitive drum, the second speed detecting means for detecting the moving speed of the transfer belt, and the image forming opening. The photosensitive drum drive means and the transfer belt drive means are drive-controlled based on a signal, and the transfer paper supply roller drive means is driven to control the primary feeding of the transfer paper to a position immediately before the transfer belt unit, and , Based on the detection signals from the first speed detecting means and the second speed detecting means, when the peripheral speed of the photosensitive drum and the moving speed of the transfer belt match, the contact / separation device is operated and controlled. An image forming machine comprising: a control unit that operates the transfer belt unit to a transfer position. 3. A photosensitive drum on the outer peripheral surface of which a toner image is formed, a driving roller, a driving roller disposed at a distance from the driving roller, and a driving roller and the driving roller. And a transfer belt unit having a transfer belt arranged to face the photoconductor drum, a contacting / separating means for operating the transfer belt unit to a transfer position and a non-transfer position, and a rotary drive for the photoconductor drum. Photoconductor drum drive means, transfer belt drive means for operating the transfer belt, drive control of the photoconductor drum drive means and the transfer belt drive means based on an image formation start signal, and the photoconductor drum drive means And a control means for operating and controlling the contacting / separating means to move the transfer belt unit to a transfer position after a predetermined time has elapsed after driving the transfer belt driving means. Image-forming machine, characterized by comprising. 4. A photosensitive drum on the outer peripheral surface of which a toner image is formed, a driving roller, a driving roller arranged at a distance from the driving roller, and a driving roller and the driving roller. And a transfer belt unit having a transfer belt disposed so as to face the photoconductor drum, a contacting / separating unit that operates the transfer belt unit to a transfer position and a non-transfer position, the photoconductor drum and the transfer belt. A transfer paper supply device for supplying a transfer paper between the unit, a photosensitive drum driving means for rotating the photosensitive drum, a transfer belt drive means for operating the transfer belt, and a drive for the transfer paper supply device. The transfer paper supply roller driving means, and the drive control of the photosensitive drum drive means and the transfer belt driving means based on the image formation start signal, and the transfer paper supply roller drive Means for driving the transfer sheet to the position immediately before the transfer belt unit for primary feeding, and for driving the photosensitive drum driving means and the transfer belt driving means, the contacting / separating means is operated after a predetermined time has elapsed. An image forming machine comprising: a control unit that controls the operation and operates the transfer belt unit to a transfer position.