JPH0627964B2 - Image recorder - Google Patents

Description

TECHNICAL FIELD The present invention relates to an image recording apparatus, and more particularly to an image recording apparatus using a photoconductor.

BACKGROUND ART Various types of methods have been proposed as an image forming apparatus of a type that receives an electric signal of an image and records a desired image on a recording paper, but a printer using an electrophotographic method (hereinafter referred to as laser beam printer Called) is currently used as a typical non-impact printer because it is capable of high-speed printing, printing on plain paper, low noise, and high reliability.

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

In FIG. 1, reference numeral 1 is a semiconductor laser that emits a laser beam and is modulated by an image signal. The modulated laser light is made into laser light having a predetermined beam diameter in the beam expander 3 and enters the polyhedral reflecting mirror 4. The polyhedral reflecting mirror 4 has a plurality of reflections and is rotated at a predetermined speed by a constant speed rotation motor 5. An image is formed as spot light on the photosensitive drum 2 by the image forming lens 6 having the f-θ characteristic. As the photosensitive drum 2, an amorphous Si photosensitive body, an OPC photosensitive body (organic photosensitive body) long wavelength sensitivity-improved amorphous Se photosensitive body, or the like is used.

The surface of the photoconductor is uniformly charged by the charger 7 and then scanned by a laser beam to form an electrostatic latent image.
This latent image is developed by the developing device 8. The developed image is transferred onto the transfer material 9 by the transfer charger 10 and separated from the photoconductor 2 by the separation charger 11. Then, the fixing device 12 fixes the developed image on the transfer material 9.

In recent years, not only in copying machines but also in printers of this type, not only is a single image formed on one side of a recording material,
There is an increasing demand for a multiple printer that records one image on top of another image and a double-sided printer that records an image on a screen.

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

The recording material on which an image is formed by the method of FIG. 1, that is, the transfer material that has passed through the fixing device 12 is conveyed to the path 16 or the path 17 by the conveyance path changing pawl 15 which operates according to the double-sided or multiplex recording signal. It Here, in the case of a double-sided recording signal, the transfer material is sent through the transport path 16, and in the case of a multiplex recording signal, the transfer material 17 is sent. The selection of this path is performed by the pawl 18. Next, by the operation of the paper feed roller 19, the developed image on the photosensitive drum 2 is transferred onto the transfer material again by the transfer charger 10 through the transport path 20, and a double-sided or multiple image is formed.
After that, the transfer material is separated from the photoconductor drum 2 by the separation charger 11 and is fixed and recorded again by the fixing device 12.

As described above, in the double-sided or multi-recording printer using the conventional electrophotographic printer, 1. The transfer material conveyance path is long, which leads to an increase in the size of the apparatus, and at the same time, the transfer material jams in the conveyance path at a high rate.

2. Contamination of the transfer charger or separation charger is likely to cause transfer failure or separation failure, and it is necessary to regularly clean the charger and replace the charging wire.

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

Such problems are likely to occur.

OBJECT OF THE INVENTION It is an object of the present invention to provide an image recording apparatus having a simple transport path and capable of double-sided recording.

Another object of the present invention is to provide an image recording apparatus having a simple transport path and capable of multiple recording.

Still another object of the present invention is to provide a high speed image recording apparatus.

The present invention that achieves the above object is an image recording apparatus that forms an image by transferring a toner image formed on two electrophotographic photosensitive members, a first recording medium and a second recording medium, onto one recording medium. First and second transfer rotators that rotate in contact with each other and in contact with the respective photoconductors, and means for forming a toner image on each of the first and second photoconductors, And a means for feeding the recording material to a transfer area where the photoconductor and the transfer rotator are in contact with each other, and the recording material fed by the feeding means is provided only between the first photoconductor and the transfer rotator. To form a toner image on the recording material, and after passing between the first photoconductor and the transfer rotator, the first and second transfer rotators support the recording material. It passes through between the transfer rotary body and the second
The toner image is formed on the recording material through the space between the transfer rotary member and the photosensitive member.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 is a sectional view of the basic configuration of the image recording apparatus according to the present invention. This image recording apparatus has a first photoconductor drum 31a, a second photoconductor drum 31b, which are photoconductors, and a first transfer roller 32a and a second transfer roller 32b, which are press rotators that are in pressure contact with them. Then, the transfer rollers 32a and 32b also come into pressure contact with each other. The respective crimps are designated by the reference numerals 35, 36 and 37.
As the photoconductor drums 31a and 31b, an OPC photoconductor in which an organic optical semiconductor is provided on the surface of a rigid cylinder, an amorphous Si photoconductor in which an a-Si optical semiconductor is provided, or the like can be used. The transfer rollers 32a and 32b are formed by forming a surface layer made of a synthetic resin having a high compression elasticity on a rigid cylinder.
In this embodiment, the first photosensitive drum 31a and the second photosensitive drum 31b have the same diameter, but they do not necessarily have to have the same diameter. Although the transfer roller 32 is shown as having a smaller diameter than the photosensitive drum 31a, it may have a larger diameter. In that case, three or more photosensitive drums can be combined with one transfer roller.

The method of forming a developed image according to an image signal on the photosensitive drum 31a is as described in the above-mentioned conventional example. That is, around the photoconductor drum 31a, a charging unit 40a for uniformly charging the photoconductor 31a, and a laser for forming an electrostatic latent image corresponding to an image signal on the uniformly charged photoconductor surface. Light irradiation means 41a (hereinafter referred to as latent image forming means), developing means 50a for visualizing an electrostatic latent image, and cleaning means 51.
a, static elimination means 52a is provided.

The latent image forming means 41 in the rotating direction of the first photosensitive drum 31a.
A developing device 50a is provided downstream of a. As the developing device 50a, a known developing device used in an electrophotographic device or the like can be used.

At the first pressing portion 35, the photosensitive drum 31a and the transfer roller 32a are held in a pressed state.
The first press contact portion 35 is provided with a paper feed table 54 which is a recording material feeding means.
Recording paper 55a, which is a recording material, is supplied from a. Chart paper 5
5a is, for example, paper, cloth, plastic sheet, or the like.

The cleaning means 5 is provided further downstream of the first press contact portion 35a.
1a is provided, which is a photosensitive drum 31a after image transfer.
Remove the developer left over. Cleaning means 51
As a, a known cleaning device used in an electrophotographic apparatus or the like can be used. However, in the apparatus of this embodiment, the image transfer efficiency is higher than that in the method using the transfer charger used in the electrophotographic apparatus, and therefore cleaning is not necessarily performed. No device is required and good images can be obtained with the cleaning device removed.

A static eliminator 52a is provided further downstream of the cleaning means 51a.
Is provided. This is to remove the electric charge remaining on the photoconductor drum 31a after cleaning to prepare for the next image formation. As the static elimination means 52a,
A static elimination method using light is desirable. The developed image formed on the photoconductor 31a by the above-mentioned method is transferred to the recording paper 55a or the transfer roller 32 at the first pressing portion 35 as described later.
can be pressure transferred to a. Photoconductor drum 31 after transfer is completed
Residual developer of a is removed by the cleaning unit 51a, and residual charges are removed by the static eliminator 52a.

On the other hand, the second photosensitive 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 photosensitive drum 31a is provided around it. Regarding the constitution and operation of these means,
Since it is the same as the case of the photoconductor drum 31a, the detailed description will be omitted by adding “a” at the end of the reference number instead of “b”.

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

As will be apparent from the following description, depending on the embodiment, one of the paper feed trays, such as the paper feed tray 54a and the paper feed tray 54, may be used.
b is unnecessary.

Photosensitive drum 31a, transfer roller 32a, transfer roller 3
2b and the photosensitive drum 31b are held so as to be elastically displaceable relative to each other to facilitate the 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.

FIGS. 4-1 to 4-3 show an example in which, in addition to the constitution of the present invention, another supply means for the recording paper 55c is provided. In this example, images are simultaneously recorded on both sides of the recording paper 55c. First, each drum and each roller start to rotate in the directions of arrows A, B, C and D at the same peripheral speed by a drive system (not shown).

First photoconductor drum, that is, the upper photoconductor drum 3
An electrostatic latent image is formed on the surface 1a by the latent image forming means 41a, the latent image is developed by the developing device 50a, and a first developed image is formed on the photosensitive drum 31a. This is an image to be recorded on the surface of the recording paper 55c, for example. As shown in FIG. 4A, this developed image reaches the first pressure contact portion 35 with the rotation of the photosensitive drum 31a, where it is pressure-transferred to the transfer roller 32a and transferred to the transfer roller 32a.
Along with the rotation of a, the third pressure contact portion 37 is reached (the 4-2nd
Figure).

On the other hand, at the same time as the image formation by the latent image forming means 41a, an electrostatic latent image is also formed on the lower photosensitive drum 31b by the latent image forming means 41b, and the latent image is developed by the developing device 5.
0b to develop the second developed image into the photosensitive drum 3
It is formed on 1b. This is an image to be recorded on the other surface of the recording paper 55c, that is, the back surface in this example.
As shown in FIG. 4-2, this developed image reaches the second pressure contact portion 36 with the rotation of the photosensitive drum 31b, and is pressure-transferred to the transfer roller 32b there, and the third pressure contact portion 37 with the rotation of the transfer roller 32b. (Fig. 4-2).

The recording paper 55c is fed from the paper feed table 54c to the third pressure contact portion 37,
When it is fed in the direction of arrow K and passes through the third pressure contact portion 37, it is transferred to the front surface and the back surface of the transfer roller 3,
At the same time, the developed image is pressure-transferred from 2a and the transfer roller 32b. In this way, the recording paper 55 is used in this embodiment.
Images are recorded on both sides of c at the same time. Latent image forming means 41
The start of image formation of a, the start of image formation of the latent image forming means 41b, and the feeding of the recording paper 55c to the third press contact portion 37 are timed so that each image is formed at an appropriate position on the recording paper 55c. There is. In this embodiment, the first and second paper feed trays 54a and 54b are unnecessary.

5-1 to 5-3 show an embodiment of the present invention. In this embodiment, multiple recording is performed in which two types of images are recorded in an overlapping manner. First, each drum and each roller start to rotate in the directions of arrows A, B, C and D at the same peripheral speed by a drive system (not shown).

An electrostatic latent image is formed by the latent image forming means 41a on the first photosensitive drum 31a, that is, the upper photosensitive drum 31a, and the latent image is developed by the developing device 50a,
Image is formed on the photosensitive drum 31a. This is, for example, the first image to be recorded on the front surface of the recording paper 55a. As shown in FIG. 5A, the developed image shows the first pressing portion 3 as the photosensitive drum 31a rotates.
5, the pressure is transferred to the recording paper 55a conveyed in the direction of the arrow K at the timing of aligning the leading edge with the first image (FIG. 5-2).

In this embodiment, the recording paper 55a is electrostatically or mechanically wound around the transfer roller 32a by means 56 for holding the recording paper 55a on the transfer roller 32a, and the fifth
It continues to rotate with it, as shown in Figure 2.

On the other hand, simultaneously with the image formation by the latent image forming means 41a, an electrostatic latent image is similarly formed on the lower photosensitive drum 31b by the image forming means 41b, and the latent image is developed by the developing device 50.
and the second developed image is developed by the photosensitive drum 31.
formed on b. This is the second image to be recorded on the same surface of the recording paper 55a, that is, the front surface in this example. This developed image is, as shown in FIG. 5-2, the second pressure contact portion 36 as the photosensitive drum 31b rotates.
Then, the pressure is transferred to the transfer roller 32b, and reaches the third pressure contact portion 37 as the transfer roller 32b rotates.

The recording paper 55a wound around the transfer roller 32a is fed into the third pressure contact portion 37 by the rotation of the transfer roller 32a, and when passing through the third pressure contact portion 37, the surface of the front surface, that is, the first pressure contact portion 37a. The second developed image is 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 multiply transferred onto one surface of the recording paper 55a, and the recording paper 55a
Is discharged. The start of image formation by the image forming means 41a, the start of image formation by the image forming means 41b, and the feeding of the recording paper 55a to the first press contact portion 35 are timed so that each image is formed at an appropriate position on the recording paper 55a. ing. Also in this embodiment, the second and third paper feed trays 54b and 54c are unnecessary. Of course, conversely, multiple recording may be performed by the press contact portion 37 using only the second paper feed table.

Further, as a modified example of this embodiment, the first developing device 50
If the colors of a and the developer of the second developing device 50b are made different,
Two-color multiplex recording can be performed.

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

6-1 to 6-4 show still another embodiment. In this example, up to the multi-recording in the third pressure contact section 37, the 5-1st to 5th
3 is the same as the embodiment in FIG.

After the 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 manner as the winding around the first transfer roller 32a, and the sixth −
The rotation continues with it as shown in FIG.

On the other hand, the latent image forming means 41b further forms a third image, which is then imaged 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 of the latent image forming means 41b, that is, the formation of the third image, is timed with the feeding of the recording paper 55a to the second pressure contact portion.

In this way, according to the present embodiment, double-sided recording can be performed on the recording paper, and multiple recording can be further performed on one side.

Figures 7-1 to 8-3 show still another embodiment. In this embodiment, images are simultaneously formed on both recording papers 55a and 55b. First, each drum and each roller is driven by a drive system (not shown) so that the arrows A, B and C respectively
And starts to rotate in the direction of D at the same peripheral speed.

An electrostatic latent image is formed by the latent image forming means 41a on the first photosensitive drum 31a, that is, the upper photosensitive drum 31a, and the latent image is developed by the developing device 50a,
Image is formed on the photosensitive drum 31a. This is an image to be recorded on one surface of the recording paper 55a.
As shown in FIG. 7A, this developed image reaches the first pressure contact portion 35 with the rotation of the photosensitive drum 31a, and there, in the direction of arrow K, at the timing where the leading end is aligned with the image on the photosensitive drum 31a. The fed first recording paper 55a
Is pressure-transferred to one surface (upper surface) of (FIG. 7-2).

In parallel with this, the latent image forming means 41b is formed on the second photoconductor drum 31b, that is, the lower photoconductor drum 31b.
An electrostatic latent image is formed by the above, and the latent image is developed by the developing device 50b, and a second developed image is formed on the photoconductor drum 31b. This is an image to be recorded on one surface of the recording paper 55b. As shown in FIG. 7A, this developed image reaches the second pressure contact portion 36 with the rotation of the photosensitive drum 31b, and there the arrow K indicates the timing at which the front end is aligned with the surface image on the photosensitive drum 31b. The pressure-transferred one surface (lower surface) of the second recording paper 55b fed in the direction (FIG. 7-2).

Thus, according to this embodiment, both the pressure contact parts 35 and 36 are
Since it is possible to simultaneously perform recording on the respective recording papers, the recording processing capability, that is, the recording speed as a whole can be increased.

As a typical operation mode of this embodiment, the latent image forming means 4 is used.
1a and 41b are operated at the same time so that both recording papers 55a
And 55b are sent to each pressure contact portion at the same timing, but in a state where both the photoconductor drums 31a and 32b and the transfer rollers 32a and 32b are continuously rotated,
If each latent image forming means 41a and 41b is driven at an independent timing and the feeding timing of both recording papers is matched with the drive timing of each latent image forming means, recording is performed independently at each pressure contact portion. Can be done. Even in this case, since the recording is performed at two places, the processing capacity is improved.

The recording information given to each latent image forming means may be the same or different.

The embodiments of the present invention have been described in detail above.
It is configured as one device including all of the means shown in the drawings, or one in which a switchback mechanism is added to these means, and is configured as shown in FIGS. 5-1 to 5-3, 6-1 to 6-4, and 7- At least 2 of the operations of the embodiment of FIGS.
Individuals may be included as a selectively executable mode.

As the latent image forming means, a known L
An ED array or an optical shutter utilizing an electric field birefringence effect (for example, a liquid crystal shutter, a PLZT shutter, a Kerr effect shutter) or the like can also be used.

Effects of the Invention As described above, according to the present invention, double-sided recording, multiplex recording, or high-speed recording can be performed with a simple recording material conveying path.

[Brief description of drawings]

FIG. 1 is a perspective view of a known recording apparatus. FIG. 2 is a sectional view of the recording apparatus of FIG. FIG. 3 is a sectional view showing the main part of the image recording apparatus according to the present invention. FIGS. 4-1 to 4-3 are cross-sectional views showing image forming examples. 5-1 to 5-3 are sectional views showing a first embodiment of the present invention. 6-1 to 6-4 are sectional views showing a second embodiment of the present invention. FIGS. 7-1 to 7-3 are sectional views showing a third embodiment of the present invention. Explanation of reference numerals 31a, 31b: Photoconductors 32a, 32b: Transfer rotators 41a, 42b; Latent image forming means 50a, 50b: Developing means

Front page continuation (72) Inventor Hidemi Egami 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Nagaho Hosono 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-55-157757 (JP, A) JP-A-57-63559 (JP, A) JP-A-54-121132 (JP, A) Actual development 62-51357 (JP, U) United States Patent 3697171 (US, A)

Claims (1)

[Claims] 1. An image recording apparatus for forming an image by transferring a toner image formed on two electrophotographic photosensitive members, a first and a second electrophotographic photosensitive member, onto a single recording material. The first and second transfer rotators that also rotate in contact with each photoconductor, the means for forming a toner image on each of the first and second photoconductors, and the photoconductor and the transfer rotator contact each other. And a means for feeding the recording material to the transfer area, and the recording material fed by the feeding means is passed only between the first photoconductor and the transfer rotating body to form a toner image on the recording material. And after passing between the first photoconductor and the transfer rotator, after passing between the first and second transfer rotators from the state in which the recording material is supported by the first transfer rotator, Further, it is possible to select to form a toner image on the recording material through the space between the second transfer rotary member and the photosensitive member. Characteristic image recording device.