JPS59204069A - Transfer device - Google Patents

Abstract

PURPOSE:To form a transfer device which does not cause a speed variation of a carrying belt by providing a driving part for driving an endless belt, on a roughly linear shifting part of the endless belt. CONSTITUTION:A screen belt 2 is constituted of a mesh of a tetron fiber, and moved in the direction as indicated with an arrow by driving rollers 64, 65. When belt joints 2a, 2b pass through the driving roller 64 and the backup roller 65, the thickness is varied, therefore, it is necessary to constitute the backup roller 65 of an elastic body such as rubber, etc., or to constitute so that a distance between the centers of the driving roller 64 and the backup roller 65 is variable. When the belt joint passes through the pair of driving rollers, a pitch line 2C is roughly linear, and is in about the center of a thickness of the belt, therefore, a circumferential speed V1 of the driving roller 64 and a circumferential speed V2 of the belt are the same, and the circumferential speed of the belt is not varied.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transfer device for a copying machine, a printing machine, a recording machine, and various other machines equipped with a mechanism for conveying a sheet to each transfer section using a conveyor belt.

Conventionally, in this type of device, for example, a color printer i
At t, the sheet is a screen belt (transport belt)
Since the image is electrostatically attracted to the image forming apparatus and conveyed through each transfer section of a plurality of electrostatic image forming units, fluctuations in the transfer speed of the screen belt cause transfer deviations (color streaks).

This screen belt 2 is usually made by cutting a fabric, butting the ends together, and pasting seam tapes 2a and 2b on the seams to create an endless belt (first
figure).

This screen belt 2 is driven by a drive roller 4 at a radius RI whose drive pitch line is approximately at the center of FIG.

However, when the seam tapes 2a and 2b of the screen belt 2 are applied to the drive roller 4, the drive pitch line becomes R2, which is greater than R1, as shown in FIG. 2, and the belt speed 1 is increased only at that time.

This speed fluctuation results in a speed fluctuation (increase in speed) of the sheet on the screen belt, which causes elongation of the transferred image and color misalignment between each color, which is an undesirable drawback for multi-transfer color images, for example. It is something that you have.

Therefore, an object of the present invention is to provide a novel transfer device that is improved in view of these drawbacks.

Another object of the present invention is to provide a water transmission device in which the speed of the conveyor belt does not fluctuate.

That is, the main structure of the present invention that can achieve the above object is a transfer device having an endless belt on which a sheet is placed and driven and conveyed through each transfer section, and a drive section for driving the endless belt. The transfer device is characterized in that it is provided at a substantially linear transfer portion of the endless belt.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. FIG. 3 is a sectional view of a laser beam printer to which the present invention is applied.

In FIG. 1, the apparatus of this example incorporates four sets of electrophotographic laser beam printer mechanisms as a plurality of sets of image forming mechanisms. In the figure, 1 is the main unit box of the device, ■・■・
(2) IV indicates the first to fourth 4-meter laser beam printer mechanisms (hereinafter simply referred to as plink mechanisms) that are sequentially arranged from the right side to the left side in the drawing in the main machine box 1.

The printers 3.4 and 62.61 are freely rotatably supported by idler rollers disposed below the right barrel of the first printer mechanism ρ and diagonally below the left of the fourth printer mechanism . 64
．． 65 is a drive roller of the present invention, which is driven by a drive source (not shown).

An IJ belt 2 is suspended around a group of rollers 3, 4, 62, 63, 64, and 65. This screen belt °2 is composed of a mesh of Tetron fibers, and moves in the direction of the arrow shown in the figure from the driving port to the rear 64.65VC.

Reference numeral 5 denotes a paper feeding mechanism disposed on the right side of the machine frame, 6 an image fixing device disposed on the left end thereof, and 7 a glint exit from the machine.

The printer mechanisms 1 to 2 have substantially the same structure. That is, each printer mechanism includes a drum-type electrophotographic photoreceptor 9 as an image carrier (hereinafter simply referred to as a drum) which is rotationally driven in the direction of the arrow around a shaft 8, and a drum-shaped electrophotographic photoreceptor 9 (hereinafter simply referred to as a drum) that is rotated around the drum in the direction of rotation of the drum. It consists of a charging device 10, a developing device 11, a transfer discharge device 12, a cleaning device 16, and a laser beam scanner 14 placed above the photoreceptor 9.

Laser beam scanner 14 semiconductor lasers.

It consists of a polygon mirror, an f-theta lens, a light shielding plate, etc., and receives the input of a time-series electric digital pixel signal S calculated and output from an image reading device and a computer (not shown in the figure).
A laser beam L modulated in accordance with the signal is oscillated to scan the drum surface portion between the charging device 1o and the developing device 11 in the direction of the drum generatrix, thereby exposing the drum surface.

However, the developing device 11 of the first printer mechanism I is
The developing toner of Y) is applied to the second one, which is macenter (M).
) development toner, the third one contains cyan (C) development toner, and the fourth one contains black (BK) development toner. The laser beam scanner 14 of the printer '+D 2M I in text box 1 receives the pixel signal 5 (Y) corresponding to the yellow component image of the color image, and the signal S corresponding to the mazetsuk component image in the second mechanism ■. (M), but that of the sixth mechanism ■ has a signal 5 (
C), and the signal S (BK) corresponding to the black component image is input to that of the fourth mechanism (2).

When the power is turned on to the apparatus, the laser beam scanner 14 of each printer mechanism I to Iv and other required process equipment are energized or rotated, and the heater of the fixing device 6 is energized, etc. , the device will perform a warming-up operation. Then, when the laser is turned on, the scanner reaches a predetermined number of revolutions, and the fixing roller reaches a predetermined temperature, the present grinter equipment becomes ready.

The transfer paper P as a transfer material is transferred to the paper feed guide 51 of the paper feed mechanism 5.
When it is inserted upward, its tip is detected by the first photointerrupter 52 and a start signal (start signal of the glint sequence) is generated.

In response to this start signal, the photoreceptors 9 of each printer mechanism I to (2) start rotating. The drive roller 64 is also driven at the same time,
Screen belt 2 also starts running in the direction of the arrow.

Transfer paper P has register pair 56. Paper feed guide 55. cash register/(
fix 56r The paper passes through the paper feed guide 57 and is supplied onto the screen belt 2. The transfer paper on the clean belt 2 receives corona discharge from the attraction charger 59 and is reliably attracted to the screen belt 2.

This charger 59 has a conductor guide 58 as a counter electrode.
is arranged, and it is particularly effective if this counter electrode 58 is grounded.

Furthermore, when the leading edge of the transfer paper P interrupts the downstream photointerceptors 0Y, 60M, 60C; are started sequentially. That is, the yellow version image as the color component of the color image is on the photoreceptor surface 9 of the first printer mechanism (■), the same magenta version image is on the second printer mechanism (■), and the same cyan version image is on the sixth mechanism (■). However, each parfocal image is formed in the fourth mechanism IV. The image forming principle in each printer mechanism is already well known as the Carlson process, so its explanation will be omitted.

Then, the transfer paper P is conveyed to the fixing device six times by the rotation of the rotation member 2, passing sequentially through the lower parts of the first to fourth printer mechanisms I-IV. The yellow plate image formed on the surface of the drum 9 of the first printer mechanism I on the paper surface by the transfer discharger 12 of the mechanism, and the yellow plate image formed on the surface of the drum 9 of the second printer mechanism H.
The same magenta version image, the same cyan version image of the 6th mechanism ■,
The parfocal images of the fourth mechanism (2) are sequentially superimposed and transferred to form a composite color image on the paper surface. When the paper passes through the fourth printer mechanism ■, it passes through a static eliminator 6 to which AC voltage is applied.
1, and is separated from the screen belt 2 without producing a discharge pattern.

The transfer paper P rides on the separation claw 61a and enters the fixing device 6, and the image formed thereon is fixed by the color toner, and is discharged from the output lower to the outside of the machine as a color image glint.

After the transfer paper P is discharged outside the machine, all rotations except the fixing device are stopped, and one print cycle is completed.

In order to detect the leading edge of the transfer paper P, each photo interrupter 60Y is arranged on the upstream side of the transfer section.

60M, 60C, and 60BK are photo interrogators arranged between each mechanism on the moving path of the screen belt 2 to the first to fourth printer mechanisms I to ■, which detect the sequential passage of the transfer paper P through each mechanism. The zero-order drive rollers 64 and 65, which serve to determine the image formation start timing of each mechanism, will be explained in more detail.

In FIG. 4, the screen belt 20i moving pitch line 2
Since C is approximately at the center of the belt thickness and the heald 2 is in contact with the drive roller 64 in a substantially straight line, the circumferential speed (1) of the drive roller 64 and the belt circumferential speed (2) are equal.

The backup loaf 65 may be formed of one surface and driven in order to apply a frictional force to the drive roller 64 and the belt 2 by pressing them against each other. Further, the backup roller 65 may be driven so as to have the same peripheral speed as the driving roller V1.

When the belt seams 2a and 2b pass through the driving roller 64.degree. and the backup roller 65, the thickness becomes 'f'. back amp roller 6
It is necessary to configure the distance between the centers of 5 to be variable.

In FIG. 5, the belt seam is shown passing through a pair of drive rollers. Pitch line 2CU, approximately straight line,
Since the belt is located approximately in the middle of the belt thickness, the drive roller 640 circumferential speed (1) and the belt circumferential speed V2 are the same, and there is no part where the belt circumferential speed changes. In this figure to -, the backup roller 65a is an elastic body, and in the Oi6 diagram showing an example of driven rotation, the backup roller 65b
The drive roller 64 and the bank up roller 65b are in pressure contact with each other so that the distance between their centers can be changed.

In this example as well, as in the previous example, the belt circumferential speed (2) does not change when the belt joint passes.

Now, in FIG. 6, the diameter of the drive roller 64 is
Basically, it is arbitrary, but if an arbitrary diameter is taken, if the roller 64 has eccentricity, the belt will cause speed fluctuations and color misregistration will occur.

Therefore, if the distance H between the transfer stations and the circumferential length πD of the drive roller in FIG. There will be no misalignment.

As explained above, according to the configuration of the present invention, even if a seam is formed on the endless belt, the conveying speed can be prevented from changing, so that image shift on the notebook being conveyed is prevented. Prevented. Therefore, as a result, even when the joint of the driving section l'J is transferred, the image forming process can be performed continuously without having to stop, and the speed can be increased.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views showing a conventional example, FIG. 6 is a cross-sectional view of a laser beam printer device to which the present invention can be applied, and FIGS. 4, 5, and 6 are main parts of the present invention. FIG. In the figure, 2 is a screen belt, 64 is a drive 11-
La, 65, 65a, 651) is Basokuasoglora. 1st item” ℃? So

Claims (1)

[Claims] In a transfer device having an endless belt on which a sheet is placed and driven to be conveyed through each transfer section, a drive section for driving the endless belt is provided in a substantially linear transfer section of the endless belt. Featured transfer device.