JPH0553448A - Electrophotographic recording device - Google Patents

Abstract

PURPOSE:To easily and surely set a transfer belt as preset, improve the belt performance, and provide a high-quality density by arranging belt tension detecting means on the transfer belt and side plate of a recording device. CONSTITUTION:A record carrier conveying means is constituted of at least a transfer belt 11 suspended on a sheet feed side roller 13 and a sheet separation side roller 12, and the sheet feed side roller 13 or the sheet separation side roller 12 can be moved in the belt longitudinal direction for adjustment. Belt tension detecting means 25, 26 displaying fixed quantities are arranged on both sides of both end sections of the transfer belt 11 and the fixed section of the record carrier conveying means faced to each other, and the change quantity of the transfer belt 11 in response to the fixed quantity of the fixed section of the record carrier conveying means is detected to set belt tension. The detecting means 25, 26 are arranged on the end section of the transfer belt 11 of the transfer unit of an electrophotographic recording device and the side plate 24 of the record carrier conveying means. The belt tension can be easily and surely set, and a high-quality image can be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic recording apparatus capable of recording on various types of paper by applying electrophotographic technology.

[0002]

2. Description of the Related Art In recent years, the demand for recording information on various types of paper has increased, and in response to this, the paper is adsorbed and conveyed to an endless transfer belt, and the toner image on the photoconductor is transferred to this paper. There is a way to reproduce the information. This method requires the optimum belt tension setting in order to extend the life of the transfer belt and obtain high image quality. For example, JP-A-56-15
Japanese Patent No. 4775 proposes a structure in which the bracket 24a on the driven roller 20 side is adjusted in the longitudinal direction so that the tension of the transfer belt can be adjusted. here,
The following problems occurred. For example, the transfer unit 10
It is assumed that the main configuration of is configured as shown in FIG. Here, 12 is a paper separating side roller, 13 is a paper feeding side roller, 14 is a cleaner facing roller, 17 is a transfer device, and 15 is a paper pressing roller arranged between the transfer device 17 and the paper feeding side roller 13. The transfer belt 11 includes rollers 12, 13, 14, 1
It is stretched around 5, and is rotated and run at a constant speed in the direction of arrow b by the sheet feeding side roller 13. Here, the photosensitive drum 1 is shown by a dotted line. The recording paper 6 is adsorbed and conveyed onto the transfer belt 11 and sent in the direction of arrow b, and the toner image on the photosensitive drum 1 is transferred onto the recording paper 6. In this example, the paper feed side roller 13
Is used as the drive roller, the paper separation side roller 12 may be used as the drive roller.

When a voltage of 4.5 to 6 kV was applied to the transfer device 17, image information having sufficient density could be reproduced. Here, 16 is a belt cleaner for removing the toner adhering to the transfer belt 11.

However, in the configuration of FIG. 3, the tension of the transfer belt is grasped quantitatively while measuring the incorporated belt circumference, and the feed side roller 13 is finely adjusted (adjusted) in order to correspond to a predetermined target value. The mechanism was not shown), and was set afterwards. Therefore, the setting was not easy.

[0005]

As described above, the good example of the transfer belt transfer method proposed in the conventional example also has a difficulty in setting the belt tension.

It is an object of the present invention to provide an electrophotographic recording apparatus which applies scanning line-shaped light by a laser printer to attach toner to develop the image, so that the belt tension can be set easily and surely such as transfer belt and paper. The detection means is arranged at the end portion of the side plate of the recording medium conveying means, and the belt tension adjusting device is used to set the tension to a predetermined value while detecting the belt expansion, thereby obtaining a high image quality.

[0007]

SUMMARY OF THE INVENTION The present invention is directed to a photoconductor, a means for uniformly charging the photoconductor, an exposing means for scanning and exposing the photoconductor with a light output controlled by image information, and a fine powder toner. Developing means including a developing device for developing a toner image on the photoconductor by means of: a recording medium carrying means for carrying and carrying the recording medium; and the recording medium by bringing the recording medium into contact with the photosensitive body. In an electrophotographic recording apparatus having a transfer unit for transferring a toner image to the photosensitive member, a cleaning unit for removing the toner image remaining on the photoconductor after the transfer process, and a control unit for controlling these, the recording medium conveying unit is At least a transfer belt is stretched around a paper feed side roller and a paper separation side roller. The feed side roller is movable in the longitudinal direction of the recording medium conveying means, and the transfer belt and the recording medium conveying means are fixed. Disposed belt tension sensing means to the ends of both opposed to the parts, made from these opposing distance, in the electrophotographic recording apparatus characterized by sensing the tension, certainly easy belt tension setting,
A high quality image can be obtained.

[0008]

By arranging the detecting means at the end portion of the transfer belt of the transfer unit of the electrophotographic recording apparatus and the side plate of the recording material conveying means, the belt tension can be adjusted very easily and can be set in a short time, thus providing a high quality image. Can be obtained.

[0009]

The present invention will be described in detail below with reference to the embodiments shown in the drawings. It should be noted that the sizes and arrangement relationships of the following components are merely examples, and the present invention is not limited to these.

FIG. 4 is a vertical sectional view showing an example of the laser printer according to the present invention.

A cylindrical photosensitive drum 1 having a base made of, for example, a grounded aluminum tube and having a photosensitive layer thereon and rotating in the direction of arrow a has a size of, for example, an outer diameter of 100 mm (= The circumference is 314 mm) and the length is 304 mm. Charger 2 for uniformly charging the surface of the photosensitive drum 1
Is a scorotron configuration with a grid. The photosensitive drum 1 is charged to −650V in this example.

In this example, the exposure apparatus 3 is composed of a semiconductor laser diode, a rotary polygon mirror, a scanner motor for rotating the rotary polygon mirror at high speed, a lens group for focusing the laser light with high precision, a mirror group, and the like. Turning on / off the laser light emission based on image information
F control is performed to perform exposure while scanning in the length (rotation axis) direction of the photosensitive drum 1. As a result, the electric charge at the location exposed to the light disappears, and an electrostatic latent image is formed on the photosensitive drum 1.

The developing device 4 forms (develops) an information image (toner image) on the photosensitive drum 1. Although details of the developing device 4 are omitted, in the present invention, the photosensitive drum 1 is exposed by scanning.
A reversal development method is adopted in which a toner image is formed at the location where the charged electric charge disappears. The recording paper 6 in the cassette 5 is extracted by the paper feed side roller 7 and sent to the inside of the apparatus, the paper is adjusted by the registration roller 8, and the conveyance timing is accurately set.
Then, the recording paper 6 is sent to the next transfer unit 10 along the transport guide 9. In this example, the transfer unit 10
Is for transferring the image information on the photosensitive drum 1 to the recording paper 6 while the recording paper 6 is being conveyed.
1, paper separation side roller 12, paper feed side roller 13, cleaner facing roller 14, paper pressing roller 15, cleaner 1
Includes 6. Paper separating side roller 12 and paper feeding side roller 1
3, cleaner facing roller 14, paper pressing roller 15
Is attached to a side plate (not shown) of the transfer unit 10.

The transfer belt 11 is stretched around four shafts 12 to 15. The recording paper 6 sent to the transfer unit 10 is transferred onto the transfer point t by the transfer belt 11 which moves in the direction of arrow b.
Will be sent to.

The belt cleaner 16 removes the toner adhering to the transfer belt 11.

The transfer device 17 is detachably attached to the transfer unit 10 and generates a transfer electric field for transferring image information (hereinafter referred to as a toner image) on the photosensitive drum 1 to the recording paper 6. The side plate (not shown) is further fixed to the substrate 18.

The static eliminator 19 neutralizes the electric charges of the recording paper 6 and the transfer belt 11 so that abnormal discharge does not occur when the recording paper 6 is separated from the paper separation side roller 12, and generates an AC corona.

Since the transfer belt 11 and the recording paper 6 receive a transfer electric field at the transfer device 17, the transfer belt 11 and the recording paper 6 are electrostatically attracted to each other when the static eliminator 19 is not operating, 6 is not affected by disturbance such as running wind,
Driving is extremely stable.

When the transfer unit 10 transfers the toner image on the photosensitive drum 1 to the recording paper 6, it is held upward by the cam mechanism 20 so that the photosensitive drum 1 and the recording paper 6 come into contact with each other. At this time, the transfer unit 10 is lowered as indicated by the dotted line, and the photosensitive drum 1 and the recording paper 6 are driven so as not to contact each other.

Reference numeral 21 denotes a fixing device for fixing the toner image transferred on the recording paper 6.

Reference numeral 22 is a cleaning device for removing the toner image remaining on the photosensitive drum 1 after the transfer.

An eraser 23 irradiates the cleaned photosensitive drum 1 with light so as to cleanly remove the charged charges of the photosensitive drum 1.

The control circuit device 100 is mainly composed of a microprocessor, and is based on a command signal and an image signal from a higher-order image information generating device, an operation panel provided in the laser printer or signals from various sensors. Control each device.

FIG. 1 is a more detailed explanatory view of the present invention, and since the left and right are substantially symmetrical, only one side is shown. For example, a transfer unit 1 including an endless semiconductive transfer belt 11, a paper feed side roller 13, a paper separation side roller 12, and a side plate 24.
0 (the paper pressing roller 15 shown in FIGS. 3 and 4 is not shown). Each of the detecting means 25 and 26 and the tension adjusting device 31 of the transfer belt 11 which display the scale graduations on both ends of the transfer belt 11 and also display the same scale graduation on the upper side of the opposing side plate 24 as described above.
It consists of FIG. 2 is an enlarged view of a main part of the tension adjusting device 31. The tension adjusting device 31 includes a support fitting 27 for the paper feed side roller 13, a fixing screw 28, and an adjusting spring 2.
9 and adjusting screw 30, by moving the adjusting screw 29 in the direction of the arrow, the sheet feeding side roller 13 can be moved in the longitudinal direction of the recording medium conveying means including the transfer belt 11 and the like.

The setting of the belt tension of the present invention will be described. As shown in FIG. 1, first, the transfer belt 11 and the side plate 2 are
4, the starting points x and y serving as the reference for both the detection means 25 and 26.
The tension adjusting screw 30 is moved in the direction of the arrow as described with reference to FIG. As shown in FIG. 1, for example, the scale on the transfer belt 11 may be adjusted to extend from x ′ to x ″ so as to correspond to the set scale y ″ on the side plate 24. As described above, setting is extremely easy. Although the detection means 25 and 26 and the belt tension adjusting device 31 are installed on both ends of the transfer unit 10, they may be similarly set on only one side. In the present invention, the detection means 26 is provided on the Mylar film having almost no expansion and contraction and set on the side plate 24. When the belt tension is set, both detecting means 25 and 26 are made to overlap with each other, so that the reading can be performed quickly. The detection means 26 on the side plate 24 is movable, so that the transfer belt 1 can be operated while running.
It is separated from 1, but only when the belt tension is set,
Since it is in contact with the transfer belt 11, the transfer belt is not damaged. Alternatively, the detection means 25, 2
By changing the configuration of No. 6, for example, the detecting means 25 was provided only on the transfer belt 11 as described above, and the belt elongation could be adjusted and set by preparing a scale equivalent to this. The detecting means 25 may be provided only on one side of the transfer belt by the above method. It is desirable that the scale as the detecting means 25 is arranged in the non-printed image portion of the transfer belt 11 that does not affect the printed image. As described above, the belt adjusting device 31 and the tension detecting means 25 and 26 can easily and surely set the predetermined belt tension.

The operation specifications of this example are described below.

Outer diameter of photosensitive drum 1: 100 mmΦ Moving speed of photosensitive drum 1: 125 mm / sec Number of exposure scanning lines: 400 lines / inch Development: Two-component reversal development method Transfer belt: Semiconductive belt made of an elastic material Paper feeding side Distance from roller center axis to transfer point t: 40 m
m Distance from the central axis of the paper feed side roller to the central axis of the paper pressing roller: 20 mm As an example, the belt tension was adjusted to about 5%, and good results were obtained for the printed images on the front and back sides of the paper.

In the present invention, the paper pressing roller is provided, but it is needless to say that the present invention can be applied without it. Further, the belt tension is set by moving the paper feed side roller, but a belt tension adjusting device may be installed on the paper separation side roller to move the paper separation side roller.

[0029]

As described above, by disposing the detecting means on the transfer belt and the side plate of the recording apparatus, the predetermined setting of the transfer belt stretched around the belt unit can be performed easily and surely, and the belt performance is improved. Was improved and a high quality density could be obtained. In addition, the service life has been significantly extended.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a main part of a transfer unit of the present invention.

FIG. 2 is an enlarged view of a main part of FIG. 1 of the present invention.

FIG. 3 is a cross-sectional view of the main configuration of the transfer unit of the present invention.

FIG. 4 is a vertical sectional side view of the laser printer of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Photosensitive drum, 2 ... Charging device, 3 ... Exposure device, 4 ... Developing device, 6 ... Recording paper, 8 ... Registration roller, 10 ... Transfer unit, 11 ... Transfer belt, 12 ... Paper separation side roller, 1
3 ... Paper feed side roller, 17 ... Transfer device, 21 ... Fixing device, 2
2 ... Cleaning device, 24 ... Side plate, 25, 26 ... Detecting means, 31 ... Belt tension adjusting device, 100 ... Control circuit.

Claims (4)

[Claims] 1. A photoconductor, means for uniformly charging the photoconductor, exposure means for scanning and exposing the photoconductor with a light output controlled by image information, and after the exposure, the photoconductor is developed with toner. Developing means including a developing device for forming a toner image on the top, recording body conveying means for mounting and conveying a recording body, and contacting the recording body with the photoconductor to transfer the toner image to the recording body. In an electrophotographic recording apparatus having a transfer unit, a cleaning unit for removing a toner image remaining on the photoconductor after the transfer process, and a control unit for controlling these, at least the recording medium conveying unit is a paper feed side roller. , Consisting of a transfer belt stretched around the paper separation side roller,
A belt tension detecting means for quantitatively displaying on both sides of both ends of the transfer belt and the fixed portion of the recording medium conveying means facing each other so that the feed side roller or the paper separating roller can be moved and adjusted in the belt longitudinal direction. Is provided, and the belt tension is set by detecting the amount of change of the transfer belt corresponding to the fixed amount of the fixed portion of the recording medium conveying means. 2. The belt tension detecting means according to claim 1, wherein the belt tension detecting means quantitatively displays on one side of both ends where the transfer belt and a fixed part of the recording medium conveying means are opposed to each other, and the belt is detected based on a change amount thereof. An electrophotographic recording device characterized by setting tension. 3. The belt tension detecting means according to claim 1, wherein the belt tension detecting means quantitatively displays on both sides of the end portion of the transfer belt, compares the detected variation amount with a reference value, and detects the belt tension on both sides of the transfer belt. An electrophotographic recording device characterized by being set. 4. The belt tension detecting means according to claim 3, wherein the belt tension detecting means is provided on one side of the end portion of the transfer belt, and the change amount is compared with a reference value to be detected to set the belt tension on one side. An electrophotographic recording device characterized by.