JPS6187170A - Electrostatic recorder - Google Patents

Abstract

PURPOSE:To attain both-side recording by developing an electrostatic image formed by an electrostatic image forming means for forming an electrostatic image on a dielectric rotary body rotated synchronously with the rotation of plural transfer rotary bodies which can be rotated which being pressed into contact with each other. CONSTITUTION:An electrostatic image is formed on an upper dielectric drum 31a by a recording head 40a and developed by a developing device 50a and the 1st developed image is formed on the drum 31a, transferred to a transfer roller 32a with pressure by the 1st press contact part 35 in accordance with the rotation of the drum 31a, and carried to the 3rd press contact part 37. Similarly, an electrostatic image is formed on a lower dielectric drum 31b by a recording head 40b and developed by a developing device 50b and the 2nd developed image is formed on the drum 32b, transferred to a transfer roller 32b by the 2nd press contact part 36 in accordance with the rotation of the drum 31b and carried to the 3rd press contact part 37. Consequently, pictures can be simultaneously recorded on both the surfaces of recording paper 55c.

Description

DETAILED DESCRIPTION OF THE INVENTION Page 1 of 1 The present invention relates to an image forming apparatus, and particularly to an electrostatic recording apparatus.

11. Various methods have been proposed as image forming apparatuses that record a desired image on recording paper or the like in response to an electrical signal of an image, but in particular, electrophotographic printers (hereinafter referred to as laser beam printers) is currently used as a typical non-impact printer because it is capable of high-speed printing, can print on plain paper, has low noise, and is highly reliable.

FIG. 1 shows a perspective view of one example of such a laser beam printer.

In FIG. 1, l is a semiconductor laser that emits laser light, which is modulated by an image signal. The modulated laser light is converted into a laser light having a predetermined beam diameter by a beam expander 3 and is incident on a polyhedral reflecting mirror 4. The polyhedral reflecting mirror 4 has a plurality of reflecting mirrors and is rotated at a predetermined speed by a constant speed rotation motor 5. Mo and f-θ
An image is formed on the photosensitive drum 2 as a spot light by an imaging lens 6 having special characteristics. As the photosensitive drum 2, an amorphous Si photoreceptor, an OPC photoreceptor (organic photoreceptor), an amorphous Si photoreceptor with improved long wavelength sensitivity, or the like is used.

The surface of the photoreceptor is uniformly charged by a charger 7, and then scanned by laser light to form an electrostatic latent image.

This latent image is developed by a developing device 8. The developed image is transferred onto the transfer material 9 by a transfer charger 1O, and separated from the photoreceptor 2 by a separation charger 11. Thereafter, the developed image on the transfer material 9 is fixed by the fixing device 12.

In recent years, not only copiers but also printers of this type have developed multi-layer printers that not only form a single image on one side of a recording material, but also multiplex printers that record one image on top of another, and printers that print images on both sides. There is a growing demand for double-sided printers that can record images.

FIG. 2 shows an example of a double-sided, multi-printer system using a laser beam printer to meet such demands.

A recording material on which an image has been formed by the method shown in FIG. 1, that is, a transfer material that has passed through the fixing device 12.

The paper is conveyed to a path 16 or 17 by a conveyance path changing pawl 15 that operates in response to a double-sided or multiplex recording signal. Here, in the case of a double-sided recording signal, the transfer material is sent through the conveyance path 16, and in the case of a multiplex recording signal, the transfer material is conveyed through the conveyance path 17. The selection of this path is performed by pawl 1B of the 0th order.

The developed image on the photoreceptor drum 2 is transferred onto the transfer material again by the transfer charger 1O through the conveyance path 20 by the operation of the paper feed roller 19, thereby forming a double-sided or multiple image. Thereafter, the transfer material is separated from the photoreceptor drum 2 by a separation charger 11, and is again fixed and recorded by a fixing device 12.

As described above, in conventional double-sided or multi-recording printers using electrophotographic printers, the following problems arise: 1. The transport path for the transfer material is long, which leads to an increase in the size of the device and at the same time increases the rate of jams of the transfer material in the transport path. .

2) Defects in transfer and separation tend to occur due to dirt on the transfer charger and separation charger, requiring periodic cleaning of the charger and replacement of the charging wire.

3. Because the conveyance path of the transfer material is long, it takes time to perform double-sided or multiple recording.

Problems such as these are likely to occur.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an electrostatic recording device that has a simple conveyance path and is capable of double-sided recording. Another object of the present invention is to provide an electrostatic recording device that has a simple conveyance path and is capable of multiple recording.

Yet another object of the present invention is to provide a high speed electrostatic recording device.

11.According to the present invention, a plurality of transfer rotors are press-contacted to each other and are rotatable, and a plurality of dielectric rotors are respectively press-contacted to the transfer rotary bodies and are rotatable in synchronization with the transfer rotary bodies. , an electrostatic image forming means provided for each dielectric rotating body to form an electrostatic image on the dielectric rotating body; and an electrostatic image forming means for forming an electrostatic image on the dielectric rotating body; a means for developing an electrostatic image formed by the electrostatic image forming means, which is provided downstream of the electrostatic image forming means and upstream of the pressure contact portion between the dielectric rotating body and the transfer rotating body; Since an electrostatic recording device is provided that transfers a developed image from each dielectric rotating body at a plurality of press-contact parts, double-sided recording, multiplex recording, or high-speed recording is possible with a simple recording material conveyance path.

Support 1 FIG. 3 is a sectional view of the basic structure of the image forming apparatus according to the present invention. This image forming apparatus includes a first dielectric drum 31a and a second dielectric drum 31b, which are dielectric rotating bodies, and a first transfer roller 32a and a second transfer roller 32b, which are transfer bodies that are in pressure contact with them, respectively. The transfer rollers 32a and 32b also come into pressure contact with each other. The respective pressure contacts are designated by reference numerals 35, 36 and 37. The dielectric drums 31a and 31b are made of a dielectric material having a volume resistivity of 10 ohms/cm or more on the surface of a rigid cylinder, and are made of several tens of JL.
It has a thickness of m.

The transfer rollers 32a and 32b are rigid cylinders on which a surface layer made of a synthetic resin with high compressive elasticity is formed. In this embodiment, the first dielectric drum 31a and the second dielectric drum 31b are the same. Although the transfer roller 32 is shown as having a smaller diameter than the dielectric drum 31a, it may have a larger diameter. , three or more dielectric drums can be combined. Dielectric drum 31a
Surrounding the dielectric drum 31a are a recording head 40a, which is an electrostatic recording means, for repeatedly forming images on the surface of the dielectric drum 31a, a developing device 50a, a cleaning means 51a, and a static eliminator 52.
A is provided.

FIG. 4 shows a cross-sectional view of an electrostatic recording head used in the present invention, which generates ions with high current density, extracts them, and selectively applies them to the dielectric drum 31a, thereby discharging the drum. It charges imagewise. This device consists of an induction electrode 41 which is a first electrode extending in a first direction (horizontal direction in FIG. 4), and a discharge electrode (41) which is a second electrode extending in a second direction different from the first direction. finger electrodes) 42, and these electrodes constitute a matrix. A third electrode 43 is located on the opposite side of the second electrode 42 from the first electrode 41, and has a plurality of openings corresponding to the matrix.

The first electrode 41 and the second electrode 42 have a first Ms.
The electric body 44 is sandwiched between them.

The second electrode 42 and the third electrode 43 also sandwich a second dielectric 45 therebetween, and the second dielectric 45 has openings 46 corresponding to the plurality of openings in the third electrode 43. By selectively applying alternating voltages between the plurality of first electrodes 41 and second electrodes 42 of the recording head having this configuration, positive and negative ions are generated near the second electrodes 42 corresponding to selected portions of the matrix. occurs.

A bias voltage is applied between the second electrode 42 and the third electrode 43, and only ions with a polarity determined by this polarity are extracted from the positive negative ions, and these ions are
It passes through the opening 47 and charges the dielectric drum 31a provided opposite the opening 47. In this manner, electrostatic recording is performed by selectively driving the plurality of first electrodes 41 and second electrodes 42. This drive may be based on the output of an electronic computer or the output of a COD that reads the image.
What is disclosed in can be used.

The recording head 40a is rotated in the rotational direction of the first dielectric drum 31a.
A developing device 50a is provided downstream. As the developing device 50a, a known developing device used in electrophotographic devices and the like can be used.

In the first press-contact portion 35, the dielectric drum 31a and the transfer roller 32 are held in a press-contact state. A paper feed tray 54a serving as a recording material feeding means is attached to the first pressure contact portion 35.
Recording paper 55a, which is a recording material, is supplied from. Recording paper 55
For example, a is paper, cloth, plastic sheet, etc.

A cleaning means 5 is further downstream of the first pressure contact portion 35a.
1a is provided, which is a dielectric drum 31a after image transfer.
Remove any developer left on top. Cleaning means 51
As a, a known cleaning device used in electrophotographic devices can be used, but in the device of this embodiment, cleaning is not necessarily required because the image transfer efficiency is higher than that of a method using a transfer charger used in electrophotographic devices. No device is required, and good images can be obtained even if the cleaning device is removed.

Further downstream of the cleaning means 51a is a static eliminator 52a.
is provided. This is to remove charges remaining on the dielectric drum 31a after cleaning and prepare for the next image formation.

In operation, an image due to electrostatic charge is formed on the dielectric drum 31a by the recording head 40a, the electrostatic charge image is developed by the developing device 50a, and the developed image is recorded in the first pressure contact portion 35 as described later. The image can be pressure-transferred onto the paper 55a or the transfer roller 32a. After the transfer is completed, residual developer is removed from the dielectric drum 31a by a cleaning means 51a, and residual charge is further removed by a static eliminator 52a.

On the other hand, the second dielectric drum 31b is provided in pressure contact with the second transfer roller 32b at the second pressure contact portion 36, and the same means as in the case of the dielectric drum 31a are provided around it. Regarding the structure and operation of these means, see Part 1.
Since this is the same as the case of the dielectric drum 31a, the detailed explanation will be omitted by replacing the raJ at the end of the reference numeral with rbJ.

The first transfer roller 32a and the second transfer roller 32b are in pressure contact with each other at a third pressure contact portion 37, and the recording paper 55a is inserted into the pressure contact portion from the paper feed tray 54a.

As will become clear from the description below, depending on the embodiment, one of the paper feed trays, for example, the paper feed tray 54a and the paper feed tray 54.
b is unnecessary.

The dielectric drum 31a, the transfer roller 32, and the dielectric drum 31b are held so that they can be elastically displaced relative to each other, thereby facilitating insertion of the recording paper into the pressure contact portion.

Next, various embodiments of the developing device according to the present invention will be described in detail.

5-1 to 5-3 show the first embodiment.

In this embodiment, images are simultaneously recorded on both sides of the recording paper 55a. First, each drum and each roller are moved by arrows A, B, and C by a drive system (not shown).
and start rotating in the direction of D at the same circumferential speed.

The first dielectric drum, i.e. the upper dielectric drum 3
An electrostatic image is formed on 1a by the recording head 40a, the latent image is developed by the developing device 50a, and a first developed image is formed on the dielectric drum 31a. This is, for example,
This is an image to be recorded on the surface of the recording paper 55c. This developed image is transferred to the dielectric drum 3 as shown in Figure 5-1.
As the transfer roller 1a rotates, it reaches the first pressure contact part 35, where it is pressure-transferred to the transfer roller 32a, and as the transfer roller 32a rotates, it reaches the third pressure contact part 37 (FIG. 5-2).

Meanwhile, at the same time as the image is formed by the recording head 40a, the lower dielectric drum 31b is also formed by the recording head 40a.
0b forms an electrostatic image, the latent image is developed by the developing device 50b, and a second developed image is formed on the dielectric drum 31b. This is an image to be recorded on the other side of the recording paper 55c, that is, the back side in this example. This developed image is shown in the v1 electric drum 3 as shown in FIG. 5-2.
As the transfer roller 1b rotates, it reaches the second pressure contact part 36, where it is pressure-transferred to the transfer roller 32b, and as the transfer roller 32b rotates, it reaches the third pressure contact part 37 (FIG. 5-2).

The recording paper 55c is fed from the paper feed tray 54c to the third pressure contact portion 37.
When the material is fed in the direction of the arrow and passes through the third pressure contact portion 37, the transfer roller 3 is applied to the front and back surfaces of the material.
The developed image is transferred from the transfer roller 2a and the transfer roller 32b simultaneously under pressure. In this way, in this embodiment, images are simultaneously recorded on both sides of the recording paper 55c. The start of image formation by the recording head 40a, the start of image formation by the recording head 40b, and the feeding of the recording paper 55c to the third pressing section 37 are timed so that each image is formed at an appropriate position on the recording paper 55c. There is. Note that in this embodiment, the first and second paper feed trays 54a and 54b are unnecessary.

According to this embodiment, double-sided recording is performed using an extremely simple recording paper conveyance path. Further, since the two dielectric drums and the two transfer rollers each have the same diameter, image formation by the two recording heads can be performed simultaneously.

6-1 to 6-3 show other embodiments of the present invention. In this embodiment, multiple recording is performed in which two types of images are recorded in a superimposed manner. First, each drum and each roller start rotating at the same circumferential speed in the directions of arrows A, B, C, and D, respectively, by a drive system (not shown).

An electrostatic image is formed on the first dielectric drum 31a, that is, the upper dielectric drum 31a, by the recording head 40a, and the latent image is developed by the developing device 50a, and the first developed image is formed on the dielectric drum 31a. formed on top. This is, for example, the first image to be recorded on the front surface of the recording paper 55a. This developed image, as shown in Figure 6-1,
As the dielectric drum 31a rotates, it reaches the first pressure contact part 35, where it is pressure-transferred onto the recording paper 55a conveyed in the direction of the arrow at the timing when the leading edge is aligned with the first image (Fig. 6-2). ).

In this embodiment, the recording paper 55a is wound around the transfer roller 32a by a means 56 that electrostatically or mechanically holds the recording paper 55a on the transfer roller 32a.
As shown in Figure 2, it continues to rotate along with it.

Meanwhile, at the same time as the image is formed by the recording head 40a, an electrostatic image is similarly formed on the lower dielectric drum 31b by the recording head 40b.

The latent image is developed by the developer 50b, and a second developed image is formed on the dielectric drum 31b. This is recording paper 5
This is the second image to be recorded on the same side of 5a, that is, the front side in this example. This developed image is No. 6-2
As shown in the figure, as the dielectric drum 31b rotates, it reaches the second pressure contact part 36, where it is pressure-transferred to the transfer roller 32b, and as the transfer roller 32b rotates, it reaches the third pressure contact part 37.

The recording paper 55a wound around the transfer roller 32a is fed into the third pressure contact part 37 by the rotation of the transfer roller 32a, and when passing through the third pressure contact part 37, the front surface of the paper 55a, that is, the first A second developed image is further pressure-transferred from the transfer roller 32b onto the surface on which the image has already been recorded.

In this way, in this embodiment, the first and second images are multiple-transferred onto one surface of the recording paper 55a, and the first and second images are transferred onto one surface of the recording paper 55a.
is discharged. Start of image formation on the recording head 40a, start of image formation on the recording head 40b, and start of image formation on the recording head 40b, and the first
The feeding to the pressure contact section 35 is timed so that each image is formed at an appropriate position on the recording paper 55a. Note that also in this embodiment, the second and third paper feed trays 54b, 54c
is not necessary. Of course, conversely, multiple recording may be performed using the pressure contact section 37 using only the second paper feed table.

Furthermore, as a modification of this embodiment, the first developing device 50
If the colors of the developer in a and the second developer 50b are different,
Two-color strip weight recording can be performed.

Further, the recording paper 55a that has passed through the third pressure contact section 37 can be triple- or three-color multi-transferred to the second pressure contact section with the rear end of the recording paper as the leading edge by a switchback mechanism (not shown).

7-1 to 7-4 show still other embodiments. In this example, up to multiplex recording in the third pressure contact section 37,
- Same as the embodiment in Figure 3.

After multiple recording is performed on the front surface by the third pressure contact portion 37, the recording paper 55a is wound around the second transfer roller 32b in the same way as the recording paper 55a is wound around the first transfer roller 32a. −
As shown in Figure 3, it continues to rotate along with it.

On the other hand, a third image is further formed by the recording head 40b, and then developed and reaches the second pressure contact portion 36. Here, the third image is transferred to the other surface of the recording paper 55a, that is, the back surface. The second image formation by the recording head 40b, that is, the formation of the third image, is synchronized with the feeding of the recording paper 55a to the second pressure contact portion.

In this way, according to this embodiment, not only can double-sided recording be performed on the recording paper, but also multiple recording can be performed on one side.

8-1 to 8-3 show still another embodiment. In this embodiment, images are simultaneously formed on both recording sheets 55a and 55b.

First, each drum and each roller start rotating at the same circumferential speed in the directions of arrows A, B, C, and D, respectively, by a drive system (not shown).

An electrostatic image is formed on the first dielectric drum 31a, that is, the upper dielectric drum 31a, and the recording head 40a, and the latent image is developed by the developing device 50a. It is formed on the body drum 31a. This is an image to be recorded on one side of the recording paper 55a.

As shown in FIG. 8-1, this developed image reaches the first press-contact part 35 as the dielectric drum 31a rotates, and there, it moves in the direction of the arrow at the timing when the tip is aligned with the image on the dielectric drum 31a. Pressure transfer is performed on one side (upper side) of the fed first recording paper 55a (FIG. 8-2).

In parallel with this, an electrostatic image is formed by the recording head 40b on the second dielectric drum 31b, that is, the lower dielectric drum 31b, and this latent image is developed by the developer 50b, The developed image is a dielectric drum dielectric drum 31
formed on b. This is an image to be recorded on one side of the recording paper 55b. As shown in FIG. 8-1, this developed image is transferred to the first
It reaches the pressure contact part 35, where it is pressure-transferred onto one side (lower side) of the first recording paper 55b fed in the direction of the arrow at the timing when the leading edge is aligned with the image on the dielectric drum 31b. (Figure 8-2).

In this way, according to this embodiment, the re-pressure welding parts 35 and 36
Since recording can be performed simultaneously on each recording paper, the recording processing capacity, that is, the overall recording speed can be increased.

In a typical operating mode of this embodiment, the recording head is
0a and 40b at the same time, the front recording paper 55a
and 55b are sent to each pressure contact part at the same timing, but each recording head 40a and 40b is sent at an independent timing while both electronic drums 31a, 32b, 8 and transfer rollers 32a and 32b are continuously rotated. If the feeding timing of one recording paper is matched with the driving timing of each recording head, each press-contact portion can perform recording independently from the others. Even in this case, since recording is performed at two locations, processing capacity is improved.

Note that the recording information given to each recording head may be the same or different.

Each embodiment of the present invention has been described in detail above, but the third embodiment
5-1 to 5-3, 6-1 to 6-3, and 7- 1
At least two of the operations of the embodiments shown in Figures 7-3 and 8-1 to 8-3 may be selectively executable modes.

In addition to the above-mentioned electrostatic recording head, a needle electrode such as a known multi-stylus can also be used.

As explained above, according to the present invention, double-sided recording, multiplex recording, or high-speed recording is possible with a simple recording material conveyance path.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a known recording device. FIG. 2 is a sectional view of the recording apparatus of FIG. 1. FIG. 3 is a sectional view of a main part of an electrostatic recording device according to the present invention. FIG. 4 is a longitudinal sectional view showing an example of an electrostatic recording head used in the electrostatic recording apparatus of the present invention. 5-1~5-3r! ! J is a sectional view showing a first embodiment of the present invention. 6-1 to 6-3 are cross-sectional views showing a second embodiment of the present invention. 7-1 to 7-4 are cross-sectional views showing a third embodiment of the present invention. 8-1 to 8-3 are cross-sectional views showing a fourth embodiment of the present invention. Explanation of symbols 31a, 31b: Dielectric rotating bodies 32a, 32b: Transfer rotating bodies 40a, 40b: Electrostatic image forming means 50a, 50b = Developing means 10th 2nd rI! J Rattan 31m Box 4 Figure 5-1 Figure 5-2 Figure 5-3 Figure 6-1
Figure 6-2 Figure 6-3 Figure 7-1N Figure 7-2 Figure 7-3 Figure 7-4 Figure 8-1 Cause Figure 8-2 Figure 8''-3

Claims (1)

[Scope of Claims] 1) A plurality of transfer rotating bodies that are in pressure contact with each other and are rotatable; and a plurality of dielectric rotating bodies that are in pressure contact with the transfer rotary bodies and are rotatable in synchronization with the transfer rotary bodies, respectively; an electrostatic image forming means provided for each dielectric rotating body to form an electrostatic image on the dielectric rotating body; a means for developing the electrostatic image formed by the electrostatic image forming means, provided downstream of the forming means and upstream of the pressure contact portion between the dielectric rotary body and the transfer rotary body, and having a plurality of An electrostatic recording device characterized in that a developed image is transferred from each dielectric rotating body at a pressure contact portion. 2) The electrostatic recording device according to claim 1, further comprising a means for feeding the recording material to the pressure contact portion between the transfer rotary body and the dielectric rotary body, , the developed image is transferred from the dielectric rotary body to the transfer rotary body, the recording material is passed through a pressure contact part between the transfer rotary bodies, and the developed image is transferred from each transfer rotary body to each surface of the recording material at the pressure contact part. An electrostatic recording device characterized by simultaneous transfer. 3) In the electrostatic recording device according to claim 1, there is provided a means for feeding a recording material to one pressure contact portion between the transfer rotating body and the dielectric rotating body, and a means for feeding the recording material to one of the transfer rotating bodies. A recording material is passed through the one pressure contact part, a developed image is transferred from one dielectric rotating body to one surface of the recording material, and the recording material is transferred and rotated by the holding means. 1. An electrostatic recording apparatus characterized in that the developed image is transferred from the other transfer rotor to the same surface of the recording material at a pressure contact portion between the transfer rotors. 4) In the electrostatic recording device according to claim 1, there is provided a means for feeding a recording material to one of the pressure contact parts between the transfer rotating body and the dielectric rotating body, and a means for feeding the recording material to the other pressure contact part. 1. An electrostatic recording device, comprising a feeding means, and in each press-contact part, a developed image is transferred from each dielectric rotating body onto a recording material fed from a respective recording member feeding means.