JPS60169878A - Electrophotographic recording device - Google Patents

Abstract

PURPOSE:To perform uniform electrostatic charge before image exposure and electrostatic charge for toner image transfer from a photosensitive drum to transfer paper with one electrifier by switching outputs. CONSTITUTION:A photosensitive drum 1 is charged electrostatically uniformly by the electrifier 10 and exposed to image light L, and toner development is carried out by a developing device 3. Transfer paper sent toward the photosensitive drum 1 is charged electrostatically by the electrifier 10 from the reverse surface to transfer the toner image to the transfer paper. A separating destaticizer 5 destaticize the transfer paper, which is separated from the photosensitive drum 1; and the toner image is fixed by a fixing device 6. Resistances connected to the grid of the electrifier 10 are switched to generate a high output during main electrostatic charge and a low output during transfer operation.

Description

Detailed Description of the Invention <Technical Field of the Invention> The present invention relates to a drum-shaped photoconductor having a photosensitive layer on its surface, a sheet-shaped photoconductor attached to a drum-shaped base, or a belt-shaped photoconductor that is A series of operations are performed by rotating the device, including charging, image exposure, and development.

Regarding the improvement of an electrophotographic device having functions such as transfer, static elimination, and cleaning, more specifically, an electrophotographic device that is improved so that it can be used as a part of image forming process equipment and has a compact and simple configuration. This relates to a recording device.

<Technical background of the invention and its problems> In a conventional electrophotographic recording apparatus, in order to perform a plurality of discharge steps, it is necessary to arrange a plurality of corona dischargers, for example, around a photoreceptor drum.

FIG. 6 is a schematic configuration diagram showing an example of a conventional electrophotographic recording apparatus.

In FIG. 6, reference numeral 1 denotes a photosensitive drum having a photosensitive layer on its surface, and the photosensitive drum 1 is supported by a shaft 9 so as to rotate in the direction of the arrow.

Various process devices for image formation are arranged around the photoreceptor drum l. As the photoreceptor drum 1 rotates, it is uniformly charged by a 411-layer corona discharger 2, and then an optical image of the original is formed by an exposure device (not shown) at the tip of i, K. (or a laser beam modulated by recording) L is irradiated, and the photoconductor tram I
- An electrostatic latent image is formed on J2.

The electrostatic latent image formed on the photoreceptor drum 1 is then developed with colored toner particles in the developing section 3 to form an original (recorded) toner image on the photoreceptor drum l'-.

The photoreceptor drum 1 further rotates, and the paper feed path is changed to B at the transfer section.
It comes into contact with the transfer paper fed in at a timing synchronized with the position of the image on the photoreceptor drum 1, and is charged with a polarity different from that of the toner by the action of the transfer corona discharger 4 from the back side of the transfer paper. Corona discharge is performed, and the toner image formed on the photoreceptor drum 1'' is transferred to the transfer paper side. Subsequently, the transfer paper is peeled off from the photoreceptor drum 1 by a peeling and charge-eliminating corona discharger 5 and sent to a fixing section 6.
A desired recorded image (copy) is obtained.

On the other hand, the photosensitive drum 1 is optically neutralized in the static eliminating section 7,
Further, in the cleaner part 8, the residual toner on the photosensitive drum 1 is removed by a far run, a blade, etc. to complete the copying (recording) cycle and prepare for the next copying (recording) cycle.

The above-mentioned copying (recording) process is just one example; - during the copying (recording) cycle, at least two corona dischargers are normally required for charging and transfer; In the case where static electricity removal is performed using light and a corona discharger 7I is used in conjunction with four corona dischargers, four corona dischargers are required. Furthermore, there is another process in which a front band 7L and secondary charging are added, and in this case, the required number of corona dischargers will further increase.

Each of these corona dischargers has a high voltage Tl according to its function.
Normally, one source is prepared, and considering the number and space of image forming process equipment placed around the photoreceptor,
The device configuration-1-1 has the problem of becoming complicated and large-sized, which leads to high costs.

<Objective of the Invention> In view of the points mentioned above, the present invention shares a part of the image forming process equipment, has a simple configuration of the apparatus, and achieves its compact size, light weight,
Our goal is to provide low-cost electronic photographic recording devices! In order to achieve this object, the present invention provides an electrophotographic recording apparatus having functions such as charging, image exposure, development 1 transfer, static elimination, and cleaning, in which the photoreceptor is A charger/transfer member disposed opposite to the photoreceptor in order to perform charging prior to image exposure and transfer the toner image (formed on the photoreceptor described in 2) in the second mode. A corona discharge device, and a means for selectively energizing the charging and transferring corona discharge device to the first or second mode in the operation of the electrophotographic recording device. has been done.

<Embodiment of the Invention> Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram of an electrophotographic recording apparatus embodying the present invention, and the same parts as those of the conventional apparatus shown in FIG. 6 are designated by the same reference numerals.

In FIG. 1, reference numeral 1 denotes a photoreceptor drum, and the photoreceptor drum 1 is, for example, a selenium (Se) photoreceptor provided on a conductive substrate such as aluminum (AI), and is held on a shaft 9. It is configured to be rotatable in the direction of the middle arrow.

In the first copy (recording) cycle (first mode), this photosensitive drum 1 is first charged with a charging/transfer corona discharger 1.
Uniformly (for example, iE heavy charge) band due to the action of 0? ■To be done. The photoreceptor drum 1 continues to rotate, passes through the inactive stripping static eliminator corona discharger 5, and finally reaches the static eliminator 7.
pass through. At this time, the static eliminator 7 is inactive and does not act on the photosensitive drum 1.

When the photosensitive drum 1 rotates further and reaches the exposure section, (
A document placed on a document table (not shown) is optically scanned by an exposure device (not shown) in synchronization with the photoreceptor drum 1, and an optical image of the document obtained is formed on the photoreceptor drum 1. Obtain an electrostatic latent image.

Subsequently, the photosensitive drum 1 on which the electrostatic latent image has been formed is
The document is developed with negatively charged toner particles in the dormitory section 3, and a toner image of the document is formed on the photoreceptor drum l. The photosensitive drum 1 continues to rotate and moves to the next cleaner section 8.
pass through.

At this time, the cleaner section 8 is inoperative, being separated from the photoreceptor drum, and the photoreceptor drum 1 on which the toner image has been formed directly reaches the charging/transferring corona discharge device 10. The photosensitive drum 1 is the second
Enter the copy cycle (second mode).

In this second copy cycle, the charging/transferring corona discharge device 10 acts as a transfer device, and the transfer paper that has passed through the paper feed path in the direction from B comes into contact with the photoreceptor drum 1 at the same time, and the transfer paper The toner image is transferred to the transfer paper by a positive corona discharge that acts from the back side.

Thereafter, the transfer paper is peeled off from the photosensitive drum 1 by the next peeling and static eliminating discharger 5 (or other peeling device, etc.) and advances to the fixing section 6.

On the other hand, the photoreceptor drum 1 continues to rotate, and the residual charge is removed by receiving the electricity removal light activated by the electricity removal unit 7. Note that this static elimination step can also be performed by AC corona discharge or corona discharge with a polarity opposite to that of uniform charging, if necessary.

The photosensitive drum 1 further continues to rotate, and the remaining toner is removed by the cleaner section 8 which is in operation.
Finish the copy cycle and prepare for the next cycle.

In one cycle of image formation, in the embodiment described in J22, uniform charging, exposure, and development are completed in the first mode cycle of the first rotation of the photoreceptor drum l, and the toner image is formed in the second mode cycle of the second rotation. Each process of transfer, peeling, static elimination, and cleaning is performed, and one copy cycle is completed in two rotations.

In the above embodiment of the present invention, both functions of uniform charging in the first mode cycle and toner image transfer in the second mode cycle are performed by using the same charging/transfer corona discharge device and a common high-voltage storage. is configured to do so.

(The output of 10 to the corona discharge device for electrification and transfer is higher than the output for pre-charging than 11 for copying.
There is li-C. For this reason, as shown in FIG. 2, the corona discharge device 10 is constructed so that the charging output and the transfer output can be selected to their respective values.

FIG. 2 is a diagram showing an example of the configuration of a charging/transferring corona discharge device i used in the present invention.

In FIG. 2, a control grid 11 is provided near the opening of the corona discharge device 10, and this control grid 11 uniformly charges the photosensitive drum 1 in the first mode, and charges the photosensitive drum 1 uniformly in the second mode. A selection control means 12 is connected for controlling the corona discharge device 10 to transfer the toner image formed on the body drum 1. This selection control means 12 is composed of a selection means 13 and a control means 14.15, and receives a timing control section S for distinguishing between the first mode and the second mode from the device control section (not shown). It is configured so that the necessary corona discharge output is selected according to the timing of charging and transfer. For example, if a high output for uniform charging is required, control including a high resistance value is required. The control grid 11 is grounded via a means 14, and when a low output for transfer is required, the control grid 11 is grounded via a control means 15 including a low resistance value. Note that 16 is a DC high voltage power supply.

FIG. 3 shows a control grid 1 that matches the high output value of the corona discharge device 10, which performs the simplest charging and transfer corona discharge device.
1 is in a floating state and has one function of uniform charging, and is also grounded via a suitable resistor 17,
A part of the generated corona discharge is caused to flow to the ground side through the control grid 11, thereby lowering the effective corona and performing the other function of transfer.

The first selection control stage 12 connected to the control grid 11 is not limited to the example described above, and may be configured using an auxiliary power source. It's good to have someone with the ability to despise.

Further, as shown in FIG. 4, the output of the high voltage power supply 16 may be directly controlled by the control means 18 without using a control grid, so that at least two values of the output are selected.

FIG. 5 is a block diagram showing one form of cycle control for the apparatus of FIG. 1 described above.

In FIG. 5, the drum cycle unit 21 includes charging means 22. Transfer means 23. Peeling means 24. Static elimination means 25. Exposure means 26. a restraining leg configured to selectively derive an output for operating the developing means 27 and the cleaning means 28, and operating the charging, exposing and developing means 22, 26 and 27 in turn in the first mode cycle; The parts are output, transferred and peeled off in the second mode cycle.

Static elimination and cleaning means 23, 24, 25 and 2
8 is output. Here, the restraining portions supplied to the charging and transferring means 22 and 23 correspond to the signal S shown in FIGS. 2 and 3 above, and the charging and transferring corona discharge device IO is controlled according to each mode. It operates selectively for charging or transfer functions.

In FIG. 1 described above, the static eliminator 7 for removing the residual charge on the photoreceptor drum 1- after the toner image transfer is at least downstream of the charging/transferring corona discharge device 1o in the photoreceptor moving direction, and the cleaning device 8 It should be placed in the first class. By disposing the static eliminator 7 before the cleaning device 8 removes the residual toner on the photoreceptor drum 1, the electrostatic adhesion between the toner and the photoreceptor drum 1 is weakened, making cleaning easier. You can. Further, the static eliminator 7 is disposed downstream of the corona discharge device 10 and upstream of the developing device 3, and the static electricity of the photoreceptor drum 1 is eliminated before passing through the developing device 3 during the second rotation during one copy cycle. By doing so, when the toner passes through the developing device 3, there is no reproduction image due to the charge charged on the photoreceptor, making it more effective in terms of toner consumption and cleaning.

Furthermore, by disposing the cleaning device 8 just upstream of the corona discharge device 10, the cleaning operation is performed in the final step of the copy cycle. Therefore, by starting the next copy cycle immediately after the deposits on the photoreceptor drum 1 are completely removed, it is possible to minimize the chances of dust, toner, etc. adhering to the photoreceptor drum l as much as possible.

f. Zinc (ZnO), cadmium sulfide (CdS)
, an organic photoconductive substance, etc., and the charging, transfer polarity, and toner charging polarity may be selected depending on the type of photoreceptor used.

Further, the photoreceptor does not need to be integrated with the drum serving as the base, and a sheet-like photoreceptor may be wound around the drum-like base. Alternatively, a belt-shaped photoreceptor may be used.

Further, the exposure device may be of a reciprocating type with an original table (fixed lens mirror, etc.) or, conversely, of a fixed type with an original table (lens mirror, etc. moved reciprocally).

The present invention is applicable to any device in which the photoreceptor rotates along a predetermined path, the peripheral surface moves in one direction, and a recorded image can be exposed on the photoreceptor in synchronization with the movement.

<Effects of the Invention> As described above, according to the present invention, the band 7 is formed on the photoconductor in the first mode prior to image exposure, and in the second mode the band 7 is formed on the photoconductor in the second mode. In order to transfer a toner image, in the operation of a charging/transferring corona discharge device disposed to face the photoconductor and an electrophotographic recording device,
Since the charging/transferring corona discharge device described in 1 is provided with a means for selectively monitoring the charging/transferring corona discharge device, charging and transfer operations can be performed by a common corona discharge device. - Downsizing of electrophotographic recording devices.

It is possible to reduce the cost and also to simplify the device.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the configuration of an electrophotographic recording apparatus embodying the present invention, FIG. 2 is a configuration diagram showing an example of a charging/transferring corona discharge device used in the present invention, and FIGS. 3 and 4. 5 is a block diagram showing another example of a charging/transferring corona discharge device suitable for use in the present invention, FIG. 5 is a diagram showing the operation cycle relationship of the device of the present invention, and FIG. 6 is a diagram showing 4.1 of the conventional device .7
FIG. DESCRIPTION OF SYMBOLS 1... Photoreceptor tram, 3... Current 1'4 device, 7 Static eliminator, 8... Cleaning device, 10... Corona discharge device for charging and transfer, 11 Control grid, I2... Selection control Means, 13 Selection means, 14.15 Control means, 16 DC high voltage power supply, 21 Drum cycle unit, L Light image, S Timing control signal. Agent Patent attorney Aihiko Fukushi (and 2 others) Figure 1 Figure 2 t [ /Q , 41°

Claims (1)

[Scope of Claims] 1. In an electrophotographic recording apparatus having functions such as charging, image exposure, development, transfer, static elimination, and cleaning, in a first mode, the photoreceptor is charged prior to image exposure; In the second mode, in order to transfer the toner image formed on the photoreceptor, a charging and transfer corona discharge device is arranged to face the photoreceptor, and in the operation of the electrophotographic recording apparatus, An electrophotographic recording apparatus comprising means for selectively energizing the charging and transferring corona discharge device to the first or second mode. 2. The electrophotographic recording apparatus according to claim 1, wherein the corona discharge device is configured such that its output is controlled in accordance with the timing of selecting the charging function and the transfer function. . 3. Claims characterized in that the device that performs the static elimination function is disposed downstream of the charging and transfer corona discharge device and downstream of the device that performs the development function. The electrophotographic recording device according to item 1. 4. Claim 4, characterized in that the device that performs the cleaning function is disposed upstream of the charging and transferring corona discharge device and downstream of the device that performs the development function. The electrophotographic recording device according to item 1.