JPH05307296A - Image forming device - Google Patents

Abstract

PURPOSE:To attain miniaturization and to evade the complexity of a constitution by arranging an image reading sensor on a recording paper carrying path on the downstream side of a resist roller of an image forming part composed of a rear exposing device. CONSTITUTION:A read original is carried by making use of the recording paper carrying path 6, and a reading sensor 20 is arranged on the carrying path 6. For instance, when this image forming device functions as a facsimile transmission part, a changeover lever 16 is changed over to an image reading side to stop the heating of a fixing roller 14 and the bias power supply of a developing device 5, respectively, and then, an image reading paper on whose front surface an image is formed is inserted into the end of the entrance of the resist roller 12 by a paper feeding tray 18. The resist roller 12 is rotated so that the read original inserted to pass on the circumference of a photosensitive drum 4 is read by the sensor 20, then carried by a transfer roller 13 and the fixing roller 14 in accordance with the rotation of the drum 4, and then ejected on a paper ejecting surface 1a in a state where the image is formed on the front surface via a paper ejecting opening.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus in which an exposing means is arranged in a photosensitive drum carrying a toner image, and particularly, it is used as a fax machine or an image scanner in addition to the function as a copying machine and a printer. The present invention relates to a possible image forming apparatus.

[0002]

2. Description of the Related Art In recent years, a so-called plain paper printer, which forms an image by an electrophotographic system instead of a conventional thermal paper system, has been widely used as an image forming unit incorporated in a fax machine. Has a structure in which all the process means from exposure to charging are arranged around the photoconductor drum, so that it is inevitably large in height, in other words, it must be a thick type, and space saving is also required. In order to achieve this, if the configuration is such that all the paper feed cassettes are housed in the apparatus, the above-mentioned thickening is further amplified, and in addition, in the apparatus, an image reading unit is additionally provided in order to have a transmission function as a fax. This necessitates an increase in the size of the device inevitably.

In order to solve such a defect, a light output corresponding to image information is provided on the inner peripheral side of a photosensitive drum formed by laminating a transparent conductive layer and a photoconductive layer on a transparent support. At the same time as or immediately after the exposure means for generating is arranged and the light output of the exposure means is focused to form a latent image on the photoconductor layer (hereinafter, the latent image forming step is referred to as exposure or exposure step). After the latent image is made into a visible image (toner image) through a developing unit facing the photoconductor drum, the toner image can be transferred onto plain paper through a transfer roller or other transfer unit. An image forming apparatus (Japanese Patent Laid-Open No. 58-153957, etc., hereinafter referred to as a backside exposure apparatus) has been proposed. In such an apparatus, an exposure means is built in, so that an independent charger is unnecessary. Due to its advantages, it is extremely advantageous for miniaturization. .

For this reason, in recent years, there is an increasing tendency to apply the backside exposure device to the image forming portion of a fax machine.

[0005]

However, even with the above configuration, the image reading section must be incorporated in the fax separately from the image forming section including the rear exposure device, and as a result, the apparatus configuration is not so great. Does not lead to miniaturization. In view of the drawbacks of the prior art, the present invention is configured such that the image reading unit can be incorporated into a part of an image forming unit including a back exposure device, and thereby a fax or image can be formed without providing an independent image reading unit. An object is to provide an image forming apparatus that can smoothly function as a scanner. Another object of the present invention is to provide an image forming apparatus capable of having a printer, a copying machine, a fax machine, and a plurality of functions of an image scanner in one machine.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a read original is configured to be conveyed by using a recording paper conveying path formed in a backside exposure device, and a reading sensor is arranged on the conveying path to form an image. The first feature is that it is readable.
This makes it possible to share the image forming conveyance path and the image reading conveyance path, and since it is sufficient to simply add a reading sensor to the conventional rear exposure apparatus, the apparatus configuration is simplified and downsized. Can be easily achieved.

However, in order for the transport path to function as an image reading device, it is not enough to simply dispose the reading sensor on the transport path, and the timing of transporting the image reading paper and
It is necessary to synchronize the reading times of the reading sensors with good consistency. Therefore, a second feature of the present invention is that the reading sensor is arranged on the downstream side of the registration means and the registration means is used to establish the synchronization.

In this case, the upstream side of the registration means may be made common, but in the case of the present invention, since the conveyance path is made common, the heating of the fixing roller and the bias power source of the developing device are used in the image reading operation. In the case of image forming operation, it is necessary to heat the fixing roller and turn on the bias power supply of the developing device respectively in the case of the image forming operation, which not only complicates the switching operation but also exposes the image erroneously during the image reading operation. This may cause development, which is not preferable.

Therefore, as set forth in claim 2, a first paper feed portion for guiding the read original and a second paper feed portion for guiding the recording paper for image formation are provided at the entrance end of the registration means, and these are switched. It is preferable to be configured so that it can be selectively fed to the registration means side by means. As a result, by switching the switching means to the image reading side, the first paper feeding section is opened, the heating of the fixing roller and the bias power source of the developing device are stopped,
On the other hand, by switching the switching means to the image forming unit side,
The second paper feeding unit is opened, and the heating of the fixing roller and the bias power source of the developing device are turned on respectively, whereby both functions can be achieved smoothly.

The common use of the conveyance path as described in claim 1 also requires a means for discriminating whether the paper output to the paper discharge tray side is a read original or a recording paper. Therefore, the present invention is characterized in that, in claim 3, a conveying path is formed by utilizing a part of the peripheral surface of the photosensitive drum, and the sensor is arranged so as to face the peripheral surface of the drum. According to this feature, in the image forming operation, the image is formed on the same surface side as the photosensitive drum, while in the case of reading the original, the original surface is located on the opposite side to the photosensitive drum. Even if both papers are output on the common paper ejection tray, they can be easily distinguished, and misjudgment does not occur.

The use of the photosensitive drum as a reading roller as described above may not be preferable because residual toner on the surface of the drum adheres to the reading paper. In such a case, as described in claim 4, by forming the sensor so as to face the conveyance path that guides the recording paper after transfer to the fixing roller side, the above-mentioned defect can be solved, and in such a case By arranging the sensor on the opposite side of the photoconductor drum with the conveyance path sandwiched, the same effect as in claim 3 can be obtained.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described in detail below as an example with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described in this embodiment are not intended to limit the scope of the present invention thereto, but are merely illustrative examples. Not too much. Figure 1
Shows an internal structure of a fax machine which also serves as a printer according to an embodiment of the present invention. The main body of the apparatus is a thick rectangular frame body 1, and a lid body which can be opened and closed centering on the left end of a planar left upper surface. 1a is formed, and its right side is raised to a substantially one-sided trapezoidal shape through a vertical step.

On the other hand, on the inner bottom surface side of the frame body 1, a paper feed cassette 2 is housed in substantially the entire area thereof so as to be drawn out from the right side in the drawing, and a photoconductor drum 4 having an exposure head 3 inserted in the upper right side thereof. Further, the developing device 5 is disposed on the left side thereof, and the recording paper conveyance path 6 is formed from the right end side of the paper feed cassette 2 toward the upper surface side from the right side along the space around the photosensitive drum 4.

In the conveying path 6, a sheet feeding roller 11 is provided at the right end of the sheet feeding cassette 2, a registration roller 12 is provided at the upper portion of the right wall of the frame body,
A transfer roller 13 is provided on the top of the peripheral surface of the drum 4, and a fixing roller 14 is provided near the paper discharge opening 1b on the stepped portion on the upper surface of the frame. The peripheral surface of the drum 4 is located between the registration roller 12 and the transfer roller 13. Function as a part of the transport path 6a. Then, the contact type reading sensor 20 is arranged on the peripheral surface of the drum so as to face it. The sensor 20 reads the read document which is urged by the elastic member (not shown) toward the peripheral surface of the drum 4 and sent from the conveying path 6a when the document is read.

On the other hand, a paper feed tray 18 for a read document is attached to the right wall of the frame body facing the registration roller 12 through a switching lever 16 and a slit opening 17. By switching the switching lever 16 to the image reading side, the space between the paper feed tray 18 and the registration roller 12 is opened, and the heating of the fixing roller 14 and the bias power source of the developing device 5 are stopped respectively. By switching to the image forming unit side, the space between the conveyance path 6 and the registration roller 12 on the side of the paper feed cassette 2 is opened, and the heating of the fixing roller 14 and the bias power supply of the developing device 5 are turned on.

The developing device 5 is provided with a developing sleeve 51, which is located in the right opening of the toner accommodating portion having a substantially rectangular shape and is brought close to the photosensitive drum 4.
And a toner replenishing port is formed on the upper surface side of the housing portion 50, and the toner can be replenished by opening the lid 1a. Further, as is well known, the photosensitive drum 4 is formed by laminating a translucent conductive layer and a photoconductive layer on a translucent support sleeve, and is rotatable in the arrow direction. The exposure head 3 is composed of an LED array 3a that generates a light output corresponding to image information and a converging lens 3b (trade name: SELFOC lens), and is on a focal line connecting the photosensitive drum 4 and the developing sleeve 51. It is configured to form an image on the photoconductor layer located.

Next, the operation of this embodiment will be described. First, when functioning as a printer or fax receiver, the photoconductor drum 4 is rotated in the direction of the arrow while supplying a pulse signal corresponding to image information to the LED array 3a, so that the light output from the LED array 3a is focused. Sex lens 3b
When a latent image is formed on the photoconductor layer after being focused by the laser beam, the latent image is visualized (toner image) through a developing sleeve 51 disposed in proximity to the photoconductor drum 4 at the same time or immediately thereafter. To do.

On the side of the conveying path 6a, the recording sheet guided from the sheet feeding cassette 2 to the side of the conveying path 6 by the sheet feeding roller 11 is once made to stand by at the entrance end of the registration roller 12 via the switching lever 16, and then the toner is discharged. By rotating the registration roller 12 in synchronism with the image, the recording paper is inserted at the transfer position along the peripheral surface of the photosensitive drum 4, and the toner image is transferred onto the recording paper via the transfer roller 13, After the image is fixed by the fixing roller 14, the recording paper can be discharged through the paper discharge opening 12 with the image formed on the lower surface on the paper discharge surface (upper surface of the lid) 1a.

Next, in the case of functioning as a fax transmission unit in the above-mentioned apparatus, the switching lever 16 is switched to the image reading side to stop the heating of the fixing roller 14 and the bias power supply of the developing device 5, respectively (however, ,
The rotation of the fixing roller 14 is not stopped), the image reading paper having the image formed on the upper surface side is inserted from the paper feed tray 18 into the entrance end of the registration roller 12, and then the registration roller 12 is rotated to expose the photosensitive material. The read document inserted on the peripheral surface of the body drum 4 is read by the sensor 20, and after being conveyed by the transfer roller 13 and the fixing roller 14 in accordance with the rotation of the drum, the discharge surface 1a is discharged through the discharge opening 12.
It is possible to eject the paper with the image formed on the upper surface side. Therefore, the image forming paper and the image surface of the read original are discharged on the front and back sides, and the distinction between them is easy.

In FIG. 2, the reading sensor 21 is connected to the transfer roller 63.
Another embodiment of the present invention arranged on the downstream transport path 56 is shown, and the configuration thereof will be briefly described. In this apparatus, the upper portion of the front wall of the thick rectangular frame 1 whose longitudinal direction is set to the front and rear is set. Side is provided with a paper feed port 61 and a lower side is provided with a paper discharge port 62.
A paper feed tray 68 and a paper discharge tray 69 are attached to the Nos. 1 and 62. A substantially horizontal U-shaped recording paper conveyance path 6 is formed so as to connect the paper feed port 61 and the paper ejection port 62, a transfer roller 63 is arranged near the U-shaped top, and the upstream side of the transfer roller 63 is provided. A paper feed roller 61 and a registration roller 62 are provided on the conveyance path 6, and a fixing roller 64 is provided at a corner of the apparatus main body on the downstream side.

Then, the transfer roller 63 and the fixing roller 6
A conveyance guide 56 is formed on the lower surface side of the conveyance path 6 between the four, and the reading sensor 21 is arranged on the guide 56.
In this case, the surface of the transport guide 56 is preferably white.

According to this embodiment, since the conveying path 6 is formed in a U shape, it is reversed and ejected in the case of image formation and guided to the ejection tray 69 side, while it is the back side in the case of image reading. The read original with the image surface formed on the side is fed to the paper feed tray 68.
After passing through the registration roller 62 at the inlet end, the registration roller 62 is rotated to transfer the transfer roller 6
After the image is read on the surface of the transport guide 56 after passing through 3, the sheet can be discharged through the fixing roller 64 and the sheet discharge opening 70 with the image formed on the lower surface of the sheet discharge tray 69. .. Therefore, also in this embodiment, the image recording paper and the image surface of the read original are discharged on the front and back sides, and the distinction between them is easy.

[0023]

As described above, according to the present invention, by arranging the image reading sensor on the recording paper conveyance path on the downstream side of the registration roller of the image forming unit composed of the back exposure device, the image reading sensor is provided. It is possible to provide an image forming apparatus that can smoothly function as a fax machine or an image scanner without providing an independent image reading unit, and thereby it is possible to avoid downsizing and complicated structure.

According to the present invention, a printer can be
It can have multiple functions of a copying machine, a fax machine, and an image scanner, and its practical use is extremely large. And so on.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating an internal configuration of an image forming apparatus according to an exemplary embodiment of the present invention.

FIG. 2 is a schematic diagram showing an internal configuration of an image forming apparatus according to another embodiment of the present invention.

[Explanation of symbols]

 63 transfer roller 5 developing means 4 photoconductor drum 3 exposing means

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location H04N 1/028 Z 9070-5C 1/23 103 Z 9186-5C

Claims (4)

[Claims] 1. An image forming apparatus configured to transfer a toner image carried on a photosensitive drum having an exposing unit inserted therein to a recording sheet conveyed along a recording sheet conveying path, wherein the conveying path is provided. An image forming apparatus characterized in that a read original can be conveyed by utilizing it, and an image reading sensor is arranged at an arbitrary position on the conveying path on the downstream side of the registration means so as to face the conveying path surface. 2. A first paper feed unit for guiding a read document to an entrance end of the registration unit and a second paper feed unit for guiding recording paper for image formation are provided on the upstream side of the registration unit. The image forming apparatus according to claim 1, wherein the image forming apparatus is configured to be capable of being selectively fed to the registration means side through the switching means. 3. The image forming apparatus according to claim 1, wherein a conveying path is formed by utilizing a part of the peripheral surface of the photosensitive drum, and the sensor is arranged so as to face the peripheral surface of the drum. 4. The image forming apparatus according to claim 1, wherein the sensor is formed so as to face a conveyance path for guiding the recording paper after transfer to the fixing roller side.