JPS6311964A - Image forming device - Google Patents

Abstract

PURPOSE:To carry a transfer material at the same carrying speed when the image on an image carrier is transferred to prevent slippage in color and disturbance in image by respectively sending control signals produced by a single reference signal generating means to drive controlling sections of the 1st and 2nd carrying means. CONSTITUTION:When a transfer material S passes through a 3rd image forming station Pc, the transfer material S is separated from a carrying belt 42 and carried into a fixing section 50. In the fixing section 50, an unfixed toner image is fixed to the transfer paper S by means of an upper and lower fixing rollers 51a and 51b, whose transfer material carrying speeds are controlled to the same transfer material carrying speed of the carrying belt 42 under the control of a fixing section drive controlling section 59. After fixing the toner image, the transfer material S is discharged into a discharge tray 35 by means of a discharge roller pair 53. Since the transfer material carrying speeds of the carrying belt 42 and upper and lower fixing rollers 51a and 51b are controlled to the same speed in accordance with the same reference signal from one reference signal generator 60, an excellent image output which is free from color slippage can be obtained on the transfer material S.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to an image forming apparatus such as a copying machine, a facsimile EIJ machine, and a laser beam printer. The present invention relates to a multiple image forming apparatus.

(b) Conventional technology Conventionally, image forming apparatuses such as electronic copying machines have
It has a series of m feeding paths for ejecting the transfer material on which the image has been fixed after being fixed to the outside of the machine. In this case, if there is a difference in the transfer material conveyance speed of each conveyance section that constitutes the conveyance path, the speed difference may cause a reduction in image quality. For example, in an electrophotographic apparatus 1 as shown in FIG. transcribed. On this occasion,
The transfer material S is attracted to the transfer belt 5 by the corona emitted from the transfer charger 6. Next, the transfer material S is attracted to a conveyor belt 9 by a suction 8I made of a fan 7, and is transferred to a fixing section 1 having fixing rollers 10a and 10b.
1 and is discharged from the device. By the way, when the transfer material S straddles the transfer belt 5 and the conveyor belt 9, the speed of the conveyor belt 9 is faster than that of the transfer belt 5 (and the transfer material adsorption force of the conveyance belt 9 is greater than the adsorption force of the transfer pels 1-5). If it is stronger, the transfer material S will slip in the transfer section 3, causing disturbances in the transferred image.

In addition, in an apparatus in which the transfer material S is directly transported from the transfer belt 5 to the fixing section 11 without the above-mentioned transport belt 9, the transfer material S is held and transported between the fixing rollers 10a and 10b of the fixing section 11. The clamping and conveying force is usually much larger than the transfer material adsorption and conveying force of the transfer belt 5. Therefore, when the same transfer material S is applied to both the fixing section 11 and the transfer section 3, the fixing rollers 10 a, 10
If the circumferential speed of b is faster than the circumferential speed of the transfer belt 5, the transfer material S will be pulled by the fixing rollers 10a and 10b, and the slippage in the transfer section 4 will increase, causing transfer misalignment on the transfer material S.

Therefore, there is an image forming apparatus in which the drive of each transport section is controlled so that there is no difference in transport speed between the transport sections.

For example, in an electrophotographic full-color image forming apparatus 20, as shown in FIG. The first to third image carriers (!!5 optical drums) 23a, 23b, 23C, and these image carriers 23
The images are sequentially conveyed to the transfer sections 26a, 26b, and 26C, which are composed of transfer chargers 25a, 25b, and 25C corresponding to the image carriers 23a, 23b, and 23c, respectively, and are deposited on the image carriers 23a, 23b, and 23c. The cyan, magenta, and yellow color toner images formed are superimposed and transferred. Next, the transfer material S is conveyed to the fixing section 27, where the toner image is fixed while being held and conveyed by fixing rollers 29a and 29b, and then discharged out of the apparatus.

The surface speed of the conveyor belt 22 is detected by, for example, a speed detecting means provided on the belt driving roller 30, and the drive of the conveying belt 22 is controlled so that the transfer material conveying speed is constant based on a detection signal from the speed detecting means. There is. this is,
If there is a difference in transfer material conveyance speed between the transfer sections 26a, 26b, and 26c, it not only causes color overlapping deviations on the transfer material S, but also expands and contracts the image information, making it difficult to output accurate images. This is because it cannot be done. Furthermore, the fixing roller 29a
, 29b feeds back a signal from the encoder of the fixing roller drive motor to a dedicated circuit that controls the drive motor, and this signal and a reference signal used to drive and control the conveyor bell 1-22 are By comparing with another reference signal, the drive is controlled so that the transfer material S is transported at the same speed as the transport belt 22.

→ Problems to be Solved by the Invention By the way, the reference signal for controlling the drive of the conveyor belt 22 and the reference signal for controlling the drive of the fixing rollers 29a and 29b are independent, so the reference signal is Due to variations in the emitted crystals or changes in humidity, a slight difference occurs in the transfer material conveyance speed between the conveyance belt 22 and the fixing rollers 29a and 29b. As a result, the fixing roller 29a,
If the transfer material conveyance speed of the transfer material 29b is faster than the transfer material conveyance speed of the conveyor belt 22, there is a risk of color overlapping deviations on the transfer material S or expansion and contraction of image information, leading to a decrease in the image quality of the obtained image output. There is. In addition, in order to avoid this color overlapping shift and image expansion/contraction, the fixing roller 2 is
The transfer material conveyance speed of the fixing rollers 29a, 29b is set slower than the transfer material conveyance speed of the conveyor belt 22.
In some cases, a loop is formed in the transfer material S between the transfer belt 22 and the transfer belt 22. However, this is the front and rear transfer material S.

An extra interval for loop formation must be ensured between the steps S, which is a problem that limits the image forming speed, especially in high-speed image forming apparatuses.

(b) Means for solving the problem The present invention aims to solve the above-mentioned problems, and includes a single reference signal generating means, and an m-motion control section of the first conveying means. The present invention is characterized in that a reference signal supply means is provided for supplying a control reference signal from the single reference signal generation means to the drive control section of the second conveyance means.

Function: Based on the above-mentioned configuration, the drive control units of the first and second conveying means that convey the transfer material for transferring the image on the image carrier each have a control reference generated by a single reference signal generating means. A signal is sent, and the first and second conveyance means are driven and controlled based on the same control reference signal, and convey the transfer material at the same conveyance speed during image transfer on the image carrier.

(f) Example Embodiments of the present invention will be described below along with the drawings.

As shown in FIG. 2, the full-color copying apparatus M1 has first, second, and third image forming stages Pa, Pb, and Pc approximately in the center of the apparatus main body 31, and a large number of image forming stages Pa, Pb, and Pc on the sides. A transfer material feeding unit 34 including a paper feeding cassette 32 for storing transfer material S, a pickup roller 33, etc. is provided, and a discharge tray 35 is provided on the other side. The image forming stations Pa, Pb, and Pc each include an image forming section 3 equipped with dedicated photosensitive drums 36a, 36b, and 36c, respectively. a, 37b, 37c are arranged,
Each of the image forming sections 37a, 37b, and 37c is provided with a dedicated charger, a developer, a transfer charger, and a cleaning device around the photosensitive drums 36a, 36b, and 36c, respectively. Furthermore, these image forming stations Pa
, Pb, and Pc are provided with dedicated laser beam scanners 39 a, 39 b, and 39 c, respectively, and these laser beam scanners 39 a, 39
b, 39 c are semiconductor lasers, polygon mirrors,
It consists of an f-theta lens, etc., receives an input of an electrical digital image signal, and scans a laser beam modulated in accordance with the signal in the generatrix direction of the photosensitive drums 36a, 36b, 36c. are exposed to light to form latent images on these photosensitive drums 36a, 36b, and 36c.

Further, below the image forming stations Pa, Pb, and PC, there are transfer units 41 a, 41 b, and 41 c, each of which includes the photosensitive drums 36 a, 36 b, and 36 c, and transfer chargers 40 a, 40 b, and 40 c, and the like. These transfer parts 41a and 41b.

A conveyor belt 42 constituting the first conveyor means is disposed so as to pass through 41c, and the conveyor belt 42 is wound around a drive roller 43 and a driven roller 45, and
It rotates in the direction of the arrow by a belt drive motor 46 connected to 3. Further, a pair of registration rollers 47 is provided upstream of the conveyor belt 42 , and an adsorption charger 49 is provided adjacent to the pair of registration rollers 47 . The fed transfer material S is timed by a pair of registration rollers 47 and transferred to a conveyor bell).
42, and the conveyor belt 4 is charged by an adsorption charger 49.
2 is electrostatically attracted. Further, a fixing section 50 is disposed between the conveyance belt 42 and the discharge tray 35, and the fixing section 50 is disposed with upper and lower fixing rollers 51a and 51b constituting a second conveyance means. has been done. The upper fixing roller 51a is provided with a fixing section drive motor 52.
are connected, and the upper and lower fixing rollers 51a and 51b are rotated in the direction of the arrow by the drive of the fixing unit drive motor 52. In addition, these upper and lower fixing rollers 51g, 51
A pair of ejection rollers 53 is provided adjacent to b, and the pair of ejection rollers 53 ejects the transfer material S fixed by the fixing section 50 onto the ejection tray 35.

On the other hand, as shown in FIG. 1, a pulse generator such as an encoder 55 is directly connected to the conveyor belt drive motor 46 that drives the conveyor belt 42.
At step 5, a rotation signal of the conveyor belt drive motor 46 is input to the belt drive control section 56. Further, a pulse generator 57 is connected to the fixing section drive motor 52, and a rotation signal of the fixing section drive motor 52 is input from the pulse generator 57 to a fixing section drive control section 59. Furthermore, a reference signal generator 60 such as a single crystal oscillator and a frequency divider 61 are provided, and the reference signal generated from the single reference signal generator 60 is frequency-divided by the divider 61. The same reference signal is transmitted to the belt drive control section 56 and the fixing section drive control section 5.
9 respectively. Then, the belt drive control section 56
Then, the reference signal is compared with the rotation signal of the conveyor drive motor 46 input from the encoder 55, and the belt drive control section 56 controls the rotation signal so that the signal from the encoder 55 is always constant. Controls the conveyor belt drive motor 46. Similarly, in the fixing unit drive control unit 59, the rotation signal of the fixing unit drive motor 52 from the pulse generation N57 is compared with the reference signal, and the fixing unit drive control unit 59
The fixing unit drive motor 52 is controlled so that the signal from the pulse generator 57 is always constant.

The full-color copying machine MM1 having the above-mentioned configuration first uses the laser beam scanner 39a of the first image forming station Pa.
The pixel number corresponding to the cyan component image of the color image is
A pixel signal corresponding to the magenta component image is input to the laser beam scanner 39b of the second image forming station Pb, and a pixel signal corresponding to the yellow component image is input to the laser beam scanner 39C of the third image forming station Pc. . First, a latent image of a cyan component color is formed on the photosensitive drum 36a of the first image forming station Pa, and then the latent image is converted into a visible image (cyan toner image) using a developer having an antoner in a developing device. be done.

On the other hand, the transfer material S fed onto the conveyor belt 1-42 from the transfer material feeding section 34 is driven by the conveyor belt 42, which is driven at a constant speed under the control of the belt drive control section 56. It is adsorbed to the surface by the adsorption charger 49, and the conveyor belt 4
2, and is transported to the transfer section 41a of the first image forming station Pa, where it is transferred to the transfer charger 40a.
The cyan toner image is transferred by. Next, a latent image of magenta component color is formed at the second image forming station Pb, and then a magenta toner image is formed by a developing device, and the magenta toner image is transferred to the transfer material S transported by the transport belt 42. is transferred to a predetermined position. Further, at the third image forming station Pc, an image of the yellow component color is formed in the same manner as described above, and yellow!・The image is transferred. Then, the transfer material S
When the transfer material S passes through the third image forming station Pc, the transfer material S is separated from the transport belt 42 and transferred to the fixing section 50. Therefore, the transfer material S is transferred to the fixing section drive control section 5.
9, the unfixed toner image is fixed by the upper and lower fixing rollers 51a and 51b, which are controlled to the same transfer material transport speed as the transfer material transport speed of the transport belt 42, and then onto the discharge roller pair 53. and is discharged onto the discharge tray 35.

At this time, the transfer material S transported to the transport belt 42 and the upper and lower fixing rollers 51a and 51b, which are controlled to the same transfer material transport speed based on the same reference signal from the single reference signal generation N60, has the following characteristics: It is possible to obtain good image output without color shift.

It should be noted that since there is no need for an unnecessarily large gap between the adjacent transfer materials S, there is no problem in increasing the conveyance speed of the transfer materials S.

Next, another embodiment of the present invention will be described based on FIG.

Note that the same parts as those of the full-color copying apparatus M described above are given the same reference numerals, and a description thereof will be omitted.

As shown in FIG. 3, the copying apparatus M2 of this embodiment has a conveyor belt 42 constituting a first conveying means, as well as a fixing belt 42 constituting a second conveying means, like the full-color copying apparatus M1 described above. 50. An optical system 67 consisting of a light source 65, a SELFOC array 66, etc. is provided above the conveyor belt 42, and an image forming section 69 is configured below the SELFOC array 66.

Further, a developing device 70 is provided adjacent to the image forming section 69.

The copying machine M2 receives, for example, 2. ．． A recording material S' such as zero paper is supplied by a pickup roller 33 to a pair of registration rollers 47, and placed on a conveyor belt 42 at a timing determined by the pair of registration rollers 47.

Next, when the recording medium S' is conveyed to the image forming section 69 by the conveyance belt 42, the reflected light from the document 71 collected by the self-checker 66 is reflected onto the recording medium S'.
At this time, a latent image is formed on the recording medium S'. Then, the recording medium S' is further conveyed by the conveying belt 42 and reaches the developing device 70, and '7g!' on the recording body S'! I(t
! is developed and sent to the fixing unit 50, where it is held and conveyed by upper and lower fixing rollers 51a and 51b, where the image (↑) is fixed and output onto the output tray 35. .

At this time, the forwarding belt drive motor that drives the conveyor belt 42 of the device M2 and the fixing section drive motor that rotates the upper and lower fixing rollers are connected to each other from a single reference signal generator 60, as in the above-mentioned full color copying device M1. The drive is controlled based on the same reference signal generated, and the transport bell! -42 and the upper and lower fixing rollers 51a and 51b have the same recording medium S' conveyance speed, and a good image without disturbance can be obtained on the recording medium S'.

In addition, in the above-mentioned first and second embodiments, the conveyor belt 1
Although the configuration is such that a pulse generator such as an encoder is used to obtain rotation signals of the respective drive motors for driving and controlling the upper and lower fixing rollers of the fixing section, the present invention is not limited to this.
It may also be configured with a speed detection word disposed on the surface of a conveying means such as a conveying belt or a fixing roller, or the like, from which speed fluctuations of these conveying means can be extracted as an electrical signal.

Alternatively, the first and second conveyance means (eg, a conveyance roller on the paper feeding side or a conveyance section upstream of the fixing section) may be used.

(G) As described in detail, according to the present invention, the drive control units of the first and second conveyance means for conveying the transfer material for transferring the image on the image carrier each have a single standard. Since the control signal generated by the signal generating means is sent, the transfer material during image transfer on the image carrier can be conveyed at the same speed,
It is possible to prevent image disturbances such as color overlapping deviations or expansion/contraction of image information due to differences in the conveyance speeds of the conveyance means that convey the transfer material during image transfer.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a drive control section for the conveying means in the transfer section and fixing section of a color copying apparatus according to an embodiment of the present invention, FIG. 2 is a side view of the full-color copying apparatus, and FIG. Copying side views according to other embodiments, FIGS. 4 and 5 are side views of conventional image forming apparatuses. M, , M2... Image forming device (full color copying device,
(nasophotographing device), 42... transfer unit conveyance means (Wll
bevel), 51a, 51b...conveyance means of the fixing section (upper and lower rollers), 56...drive control section of the first conveyance means (belt drive control section), 59 drive control section of the second conveyance means (Fixing unit drive control unit), 60...
・Single reference signal generation means (reference signal generator), 6
1...Reference signal supply means (frequency divider).

Claims (2)

[Claims] (1) An image bearing member, a first conveying means and a second conveying means for conveying a transfer material for transferring an image on the image bearing body,
In an image forming apparatus comprising a conveying means and a transfer section provided within a conveying area of the second conveying means, and driving and controlling the first and second conveying means respectively, a single reference signal is generated. and a reference signal supply means for supplying a control reference signal from the single reference signal generation means to the drive control section of the first conveyance means and the drive control section of the second conveyance means. An image forming apparatus characterized by: (2) The first conveyance means is a conveyance means of a transfer section that transfers the transfer material, and the second conveyance means is a conveyance means of a fixing section that fixes the transfer material. 1
The image forming apparatus described in .