JPH0229217B2 - ZOKIROKUHOHO - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to improvements in technology in the fields of printing, copying, etc.
That is, the present invention relates to an improvement in a method of forming an image on a recording medium, particularly to an improvement in a method of forming images on both sides of a recording medium.

[Prior art]

Conventionally, the process of forming images on both sides of a recording medium is to first perform the step of forming an image on one side of a large number of recording bodies, temporarily store this in a stacker, and then apply the process of forming an image on one side. It was a process in which the step of forming images was performed on a large number of recording bodies. In the image forming process using dry electrophotography, the image transferred from the primary image forming body to the recording medium is an unfixed image, and it cannot be fixed by simply leaving it as is; a fixing step is required. , the image forming process is not completed until the transfer process and the fixing process are completed. In this case, the process of forming an image on one side of the recording medium is performed on a large number of sheets, the ones that have already been recorded on one side are temporarily stored, and then the process of forming an image on the other side is performed on a large number of sheets. This process was essential for the configuration of a recording device that performs double-sided recording.

[Problem that the invention seeks to solve]

Machines that automatically record on both sides of a recording medium have been put to practical use in printers, copying machines, etc., but as explained above, conventionally, a recording medium that has already been recorded on one side was temporarily stored in a stacker. The mechanism is such that the paper is stored on one side and then re-fed when recording on the other side, which makes the device complicated, and paper jams occur during re-feeding. There were problems such as difficulty in obtaining reliability. To solve this problem, for example, Japanese Patent Laid-Open No. 121132/1983 proposes an apparatus that uses two photoreceptors to record from both sides of the recording medium without storing the recording medium. However, it is not practical because the apparatus becomes large and there are problems in transporting the recording medium.

Therefore, the present invention solves these problems, and although it has a double-sided recording function, it can be made into a relatively compact recording device, and sufficient reliability can be ensured, making it suitable for practical use. The purpose of the present invention is to provide a recording method that is highly versatile and capable of high-speed recording.

[Means for solving problems]

The above purpose includes a step of forming a first electrostatic image on an image forming member and then developing it to form a first toner image, a step of transferring the first toner image to a first intermediate transfer member, and a step of transferring the first toner image to a first intermediate transfer member. a step of forming a second electrostatic image on the image forming body and then developing it to form a second toner image; a step of transferring the second toner image to a second intermediate transfer body; and a step of transferring the second toner image to the first intermediate transfer body. A recording paper is sandwiched between the first toner image on the transfer body and the second toner image on the second intermediate transfer body, and the three toner images pass through the pressure contact part in synchronization, and the recording paper This is achieved by an image recording method comprising the step of simultaneously forming the first toner image and the second toner image on both sides of the image.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An automatic double-sided copying machine that is an embodiment of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a schematic diagram showing the first step of the image recording process according to the present invention.

In the figure, 1 is an automatic document feeder, and document D
is fed out by a feeding member 2, conveyed to a conveying belt 3 stretched by a driven roller and a tension roller, and placed on a document table glass 4. The original D exposed on the original platen glass 4 is stored in the original holder 5. Charger 6g and exposure optical system 6 (6a and 6b are light sources, 6C, 6d and 6
(e is a mirror, 6f is a fixed lens) The electrostatic latent image formed on the drum-shaped charge carrier 7 by being charged and exposed reaches the developing device 7 as the charge carrier 7 rotates in the direction of the arrow. The toner is developed to form a visible image 9.

According to the present invention, the photoreceptor used as the charge holding member 7 is preferably one having excellent heat resistance and surface strength for the reasons described below, such as an alumofous hydrogenated/nitrided silicon photoreceptor, an alumofous hydrogenated - Examples include a carbonized silicon photoreceptor and a network-structured arsenic/selenium photoreceptor.

In addition to the above-mentioned inorganic photoreceptors, for example, poly-N-vinylcarbazole and 2,4,7-trinitro-9
-Organic photoreceptors containing fluorenone can also be used.

Furthermore, although a drum-shaped photoreceptor is used in this embodiment, a belt-shaped photoreceptor may also be used.

The visible image 9 thus formed on the charge carrier 7 reaches the transfer positions T, T' onto the two intermediate transfer members 10, 10' as the charge carrier 7 continues to rotate.

The intermediate transfer body 10, 10' according to the present invention has an endless belt shape (hereinafter referred to as an intermediate transfer belt),
The materials include a heat-resistant, elastic and adhesive transfer layer such as silicone rubber or Teflon rubber, and a heat-resistant substrate such as stainless steel plate, polyimide, polyimide amide, polyamide, polyester, and polyacrylate. A laminate composed of:

According to the present invention, the intermediate transfer belts 10 and 10' are stretched by transfer pressure rollers 11 and 11', tension rollers 12 and 12', and heat fixing rollers 13 and 13', respectively, and rotate. Can be done.

Therefore, the visible toner image 9 on the first charge carrier 7 obtained from the first object to be copied is first pressed against the surface of the charge carrier 7 by the transfer pressure roller 11, at the center of the right side in the figure. The image is pressed and transferred onto the transfer belt 10 at the transfer position T.

At this time, the intermediate transfer belt 10' on the left side of the figure, which presses and transfers the second visible toner image obtained from the second object to be copied, rotates to the left in the figure about the heating fixing roller 13'. The transfer press roller 11' is separated from the surface of the charge carrier 7.

The transferred image 9' transferred onto the intermediate transfer belt 10 as described above moves as the intermediate transfer belt 10 rotates, and is detected when the rear end of the transferred image 9' passes the transfer pressure roller 11. The rotation of the intermediate transfer belt 10 is detected by a member (not shown), and the rotation of the intermediate transfer belt 10 is stopped based on the detection signal. The intermediate transfer belt 10, which has stopped rotating, simultaneously rotates to the right in the figure about the heat fixing roller 13, and the transfer pressure roller 11 of the intermediate transfer belt 10 and the surface of the charge carrier 7 are separated from each other. Ru. (See FIG. 2) FIG. 2 is a schematic diagram showing the second step of the image recording process according to the present invention.

The second copy target of the next page (or back side) of the original D is exposed to light, developed with toner, and transferred to the charge carrier 7.
The visible image 9 formed thereon reaches the transfer position T' as the charge carrier 7 rotates. In synchronization with this, the intermediate transfer belt 10' on the left side of the figure rotates in the right direction about the heat fixing roller 13', and the transfer pressure roller 11' contacts the surface of the charge carrier 7 at the transfer position T'. Contact. At the same time, the intermediate transfer belt 10' starts rotating in the direction of the arrow in the figure.

Thus, the visible image 9 on the charge carrier 7 is transferred onto the intermediate transfer belt 10' by the pressing force of the transfer pressure roller 11' of the intermediate transfer belt 10'. When the rear end of the transferred image 9'' transferred onto the intermediate transfer belt 10' passes the transfer pressure roller 11', it is detected by a detection member (not shown), and the rotation of the intermediate transfer belt 10' is detected. It will be stopped based on the signal.

When the rotation of the intermediate transfer belt 10' stops, the intermediate transfer belt 10' again rotates to the left in the figure around the heating fixing roller 13', and the transfer pressure roller 11' presses the surface of the charge carrier 7. move away from

According to the present invention, after the intermediate transfer belt 10' is tilted to the left about the heating fixing roller 13', the rotation of the intermediate transfer belt 10' is reversed (in the direction of the dotted arrow in the figure). and intermediate transfer belt 1
The position of the transferred image 9'' formed on the intermediate transfer belt 10 is moved to a position that is relatively coincident with the position of the transferred image 9' that was previously formed on the intermediate transfer belt 10, and then based on the detection signal, Above intermediate transfer belt 1
Stop the reverse rotation of 0'. (See FIG. 3) FIG. 3 is a schematic diagram showing the third step of the image recording process according to the present invention.

In the third step of the image recording process, images are transferred and fixed simultaneously on both sides of the recording paper by heating fixing rollers 13 and 13'. In this third process, the recording paper P is fed from the paper feed cassette 14 at the same time as the intermediate transfer belt 10' starts to reverse rotation, and its leading edge is heated at an intermediate position between the intermediate transfer belts 10 and 10'. When approaching the fixing rollers 13, 13', a detection signal is activated, and the intermediate transfer belts 10 and 10', which can carry the transferred images 9' and 9'' at relatively coincident positions with the recording paper P as the center, simultaneously move. It starts rotating in the direction of the arrow, and is brought into pressure contact with the heating fixing rollers 13 and 13' with the recording paper P in between, so that the toner images are transferred and fixed on both sides of the recording paper P at the same time.

Recording paper P on which the image has been transferred and fixed as described above
is ejected in the direction of the arrow in the figure, and the double-sided recording of the image is completed. When the recording of both images is completed, the intermediate transfer belt 10 returns to its original position, returns to the configuration shown in FIG. 1, and the next image recording is performed.

On the other hand, the charge holding body 7 after the pressure transfer of the toner visible image 9 is transferred to the charge removing device 1 in the same manner as in the normal process.
5 and a cleaning device 16, the charges are removed and cleaned, respectively, and the materials are reused.

According to the present invention, since the toner image is heat-fixed using two intermediate transfer belts, the intermediate transfer belt is constantly exposed to heat by the heat-fixing roller, and the intermediate transfer belt that retains this heat is As already mentioned, since the toner image is transferred from the charge carrier by pressure contact, it is particularly preferable that the charge carrier is made of a photoreceptor that is heat resistant and has good surface strength. That's right.

Furthermore, in the present invention, the first image is not necessarily transferred to the intermediate transfer member on the right side of the figure, and then the second image, for example, the image of the next page or the back page of the original, is transferred to the intermediate transfer belt on the left side of the figure. There is no need to transfer the first image to the intermediate transfer belt on the left in the diagram.
Then, the image of the next page or the back page of the document may be transferred to the right intermediate transfer belt. Furthermore, although the intermediate transfer belt is not provided with a cleaning device in the present invention, it is of course possible to arrange a cleaning device at an appropriate location as required.

In the embodiment described above, one primary image forming body is used to transfer images to these two intermediate transfer bodies, but it is also possible to use two primary image forming bodies and make the intermediate transfer body correspond to each of them. It is also possible to take this configuration. In this way, exposure, development, and primary transfer can be performed simultaneously on both sides of the image, making high-speed recording possible.

Furthermore, although the embodiment described earlier is a copying machine,
For example, the present invention can be effectively used in a printer that forms a latent image or an unfixed image on a primary image forming member using electrical signals or the like.

〔Effect of the invention〕

The automatic double-sided copying machine equipped with an automatic document feeder used in the method of the present invention simultaneously transfers images onto two intermediate transfer bodies stretched by mutually adjacent heat fixing members onto both sides of recording paper. Since it can be thermally transferred and fixed, it has the advantage of being able to make double-sided copies in a one-touch process and having a small and simple structure.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram showing the first step of the image recording process according to the present invention, FIG. 2 is a schematic block diagram showing the second step of the above recording process, and FIG. It is a schematic configuration diagram showing three processes. 1... automatic document feeder, 7... charge holder, 8...
Developing device, 9... visible image, 9' and 9''... transferred image,
10 and 10'...intermediate transfer body, 11 and 1
1'...Transfer pressure roller, 12 and 12'...Television roller, 13 and 13'...Heat fixing roller, P...Recording paper, T and T'...Transfer position.

Claims (1)

[Claims] 1 A step of forming a first electrostatic image on an image forming member and then developing it to form a first toner image, a step of transferring the first toner image to a first intermediate transfer member, a step of forming a second electrostatic image After the image is formed on the image forming member, it is developed to form a second toner image, a step of transferring the second toner image to a second intermediate transfer member, and a step of transferring the second toner image to the first intermediate transfer member. A recording paper is sandwiched between the first toner image and the second toner image on the second intermediate transfer body, and the three toner images pass through the pressure contact section in synchronization, and the two toner images are applied to both sides of the recording paper. An image recording method comprising the step of simultaneously forming a first toner image and a second toner image.