JPS63189348A - Image forming device - Google Patents

Abstract

PURPOSE:To make the vertical position relation between the surface and rear face of a sheet coincident by providing the first and second feedback means reversing the surface/rear face relation of an image-formed medium twice respectively and the first and second temporary storage means. CONSTITUTION:The first and second stackers 24, 25 are provided below a sensitive body drum 12 and communicated to a heat roller 18 via transfer paths 16d, 16h. The stackers 24, 25 are also communicated by 1st and 2nd guides 26, 27 of circular arc shape. For the double copying with this constitution, the sheet transferred with an image on the surface is sent to the first stacker 24 and temporarily waits, with its rear face kept upward. Next, for the copying on the rear face, the sheet is mounted on the second stacker 25 via the first guide 26, with its surface kept upward and the vertical position relationship kept unchanged. Furthermore, the sheet passes a transfer path 16i and is sent to a transfer section 17 for the copying on the rear face.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention 1 (Industrial Application Field) This invention relates to an image forming apparatus, and relates to, for example, an improvement in an image forming apparatus capable of forming images on both sides of an image forming medium.

(Prior Art) Conventionally, an image forming apparatus has been used as an apparatus for forming an image of an original image on paper, which is an image forming medium. Among these, there are devices that can make copies on only one side and devices that can make copies on both sides, depending on the functionality when forming an image on the paper.

FIG. 4 schematically shows an image forming apparatus capable of double-sided copying.The upper part of the image forming apparatus body 10 has a lid that can be opened and closed, and an original image holder for placing an original image to be copied. A placing section 11 is formed, and a photosensitive drum 12 for forming an electrostatic latent image on the original image is installed below the original image placing section 11 and near the center of the main body 10 of the image forming apparatus. ing. Further, a developing unit 13 is disposed on the upper right side of the photosensitive drum 12, and a paper feed cassette 14 is detachably attached to the outside right side of the image forming apparatus main body 10.

Then, the paper is taken out by the paper feed roller 15 that comes into pressure contact with the paper in the paper feed cassette 14, and the paper is taken out from the paper transport path 16a.
In the transfer section 17, the image formed by the photosensitive drum 12 and the developing device unit 13 is transferred onto a sheet of paper.

The paper on which the image has been transferred is transported by the paper transport path 16b to the heat roller 18 and fixed thereon, but after this fixing process, whether the paper is to be copied on one side or both sides,
Alternatively, even for single-sided copying, the paper conveyance path differs depending on whether development is required multiple times (for example, multiple colors).

That is, in the case of single-sided copying and only one development, after passing through the heat roller 18, the paper passes through the paper conveyance path 16c, and then from the paper ejection roller 19 to the ejection tray installed outside the left side of the image forming apparatus main body 10. It is discharged at 20.

In addition, in the case of single-sided copying and multiple development, and in the case of double-sided copying, after passing through the heat roller 18, the transport roller 21
By driving the sheet a, the sheet is sent to the stacker 22 set below the photoreceptor drum 12 along the sheet transport path 16d. Here, in the case of single-sided copying, the conveyance roller 21b
The paper is transported again to the transfer unit 11 via the paper transport path 16e, and after transferring an image in the second color, for example, it is transferred to the paper output tray 20 along the same path as in the case of one-time development described above. is discharged to. On the other hand, in the case of double-sided copying, the paper is transferred from the stacker 22 to the paper reversing unit 23 along the paper transport path 16f by driving the transport roller 21c.

Then, the paper reversed by the paper reversing unit 23 is conveyed to the transfer unit 17 via the paper conveyance path 16C by the conveyance roller 21d, and is transferred to the paper output tray 2 through the same path as for single-sided copying.
Ejected to 0.

(Problems to be Solved by the Invention) In an image forming apparatus having such a configuration, in the case of double-sided copying, in order to reverse the front and back sides of the paper on which the image has been transferred, the paper is placed in the stacker 22. After the paper is loaded, the paper reversing section 23 performs this work. However, when the front and back sides of the paper are reversed in the paper reversing section 23 in this way, while the first sheet is in the paper reversing section 23, the next sheet is kept waiting in the stacker 22, and the first sheet is It remains in a standby state until it is sent out from the section 23.

For this reason, the copying process takes time, and improvements in efficiency, such as an increase in the number of copies per unit time, have been required.

In addition, in the case of double-sided copying, the vertical positional relationship of the surface of the paper,
The vertical positional relationship on the back side is reversed. Referring to FIG. 5, it is assumed that, for example, an image rAJ is transferred onto the paper P by the transfer unit 17. This paper P is conveyed to the stacker 22 along the paper conveyance path 16d as indicated by arrows a and b in the figure in order to perform double-sided copying.

Here, the paper P is placed on standby in the stacker 22, with the surface on which rAJ is not transferred, that is, the back surface facing up. Then, as shown by arrow C, the paper transport path 16
The paper P is conveyed to the paper reversing section 23 according to f. At this time, the vertical positional relationship of rAJ of the paper P is reversed. In this way, the paper P is transported along the paper transport path 160 according to the arrows d and e, but when the paper P returns to the transfer unit 17, the front and back sides are reversed, but the vertical positional relationship of the characters rAJ transferred to the front surface is In other words, the problem arises that the top and bottom positions of the front and back sides of the paper P do not match.

This invention was made in view of the above points, and it is possible to improve efficiency such as increasing the number of copies per unit time without requiring time for the copying process, and to improve the efficiency of the copying process by increasing the number of copies per unit time. It is an object of the present invention to provide an image forming apparatus in which the vertical positional relationship of the back surface is the same.

[Structure of the Invention] (Means for solving the R illumination point) That is, the present invention includes an image forming means for forming an image on an image forming medium according to image information, and an image forming means for forming the image by the image forming means. a conveying means for conveying the image forming medium; and a conveying means for conveying the image forming medium conveyed by the conveying means, and inverting the front and back sides of the image forming medium twice in order to re-image the image forming medium conveyed by the conveying means, depending on the type. first and second return means for returning the image forming medium to the image forming means; first temporary storage means provided in the first return means for temporarily storing the image forming medium; a second temporary storage means provided in the second temporary storage means in a positional relationship opposite to the first temporary storage means; The image forming apparatus is characterized by comprising a moving means for moving the image forming medium with its front and back sides reversed.

(Function) To explain the function of the present invention, for example, when double-sided copying is performed when the traveling direction of the paper and the longitudinal direction of the paper are aligned, the paper on which the image of the original image has been transferred is fixed. After that, it is held in the first temporary storage means. When copying is to be performed on the back side of the paper, the paper is sequentially transferred from the first temporary storage means along, for example, an arc-shaped guide member, without changing the vertical positional relationship and with the front and back sides of the paper reversed. The data is transferred to temporary storage means 2.

The image is transferred and fixed on the back side of the paper whose front and back sides have been reversed, and a double-sided copy is made in which the top and bottom positions of the front and back sides match.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of an image forming apparatus according to an embodiment of the present invention, in which the image forming apparatus body 10 has a lid that can be opened and closed at the top, and an original image is placed thereon for copying. A placing section 11 is formed, and at the bottom of this original image placing section 11 and near the center of the image forming apparatus main body 10, a photoreceptor drum 12 for forming an electrostatic latent image on the original image is installed. has been done. Further, a developing unit 13 is disposed on the upper right side of the photosensitive drum 12, and a paper feed cassette 14 is detachably attached to the outside right side of the image forming apparatus main body 10. Then, the paper is taken out by the paper feed roller 15 that comes into pressure contact with the paper in the paper feed cassette 14, and is transferred to the transfer section 17 along the paper transport path 16a where it is formed by the photosensitive drum 12 and the developing unit 13. The image is then transferred to the paper.

On the other hand, a pair of heat rollers 18 are set on the left side of the transfer section 17 on an extension of the paper transport path 16b, and further on the left side of the heat roller 18 are a paper transport path 16C and a pair of paper ejection rollers. 19 are provided. A paper discharge tray 20 is installed outside the left side of the image forming apparatus main body 10 to receive paper on which an image is formed.

Further, a first stacker 2 is located below the photoreceptor drum 12.
4, and a second stacker below this first stacker 24.
stackers 25 are set respectively. These first and second stackers 25 are connected to the paper conveyance path 16d.
and the heat roller 18 at 16h, and the second stacker 25 is connected to the transfer unit 1 at the paper conveyance path 16i.
7 has been contacted. These paper conveyance paths 16
d, 16h and 16i are transport rollers 21a, respectively.
, 21e and 21f.

Further, the first stacker 24 and the second stacker 25 are also connected by a first guide 26 and a second guide 27 having an arc shape.

FIG. 2 shows the first stacker 24 and the second stacker 25, and the first guide 26 is arranged in a direction perpendicular to the paper conveyance paths 16d and 16h (on the left side in the figure), which serve as paper inlets. The second guide 27 is provided on the same side as the paper transport paths 16e and 16i, that is, in the direction orthogonal to the first guide 26. A pickup roller 2 is provided at the entrance of the first guide 26.
A paper feed member 29 with a number 8 is supported on the first stacker 24 by a shaft 30 . Similarly, the second guide 2
A paper feed member 32 having a pickup roller 31 also at the entrance of the stacker 7 is supported by the first stacker 24 by a shaft 33.

Next, the operation of this embodiment will be explained.

There are three types of image forming apparatuses depending on the type of copying and the type of development. The first case is one-sided copying and development is required only once, the second is one-sided copying and development is required multiple times, and the third is double-sided copying.

First, in the case of single-sided copying and development is required only once, the original image to be copied is placed on the original image placement section 11, and copying is started by a switch (not shown). Then, photoreceptor drum 1
2 and the developer unit 13, and the image is transferred by the transfer unit 17 to the paper that is taken in by the paper feed roller 15 from the paper feed cassette 14 and then transferred along the paper conveyance path 16a. be done. The transferred paper is then moved along the paper transport path 16b to the heat roller 18.
After being transferred to and fixed by this heat roller 18,
The paper is discharged from the paper discharge roller 19 to the paper discharge tray 20 via the paper conveyance path 16c. The above operations are performed for the desired number of sheets.

Next, if one-sided copying requires multiple development steps (for example, multiple colors), the steps up to the fixing step are the same as those described above for only one development step, so we will explain everything from placing the original image to the fixing step. omitted. Then, the paper fixed by the heat roller 18 is transferred to the paper transport path 16h by the drive of the transport roller 21e, and is placed on standby in the second stacker 25. Here, once the desired number of sheets has been copied for the first time, the sheets are taken out from the second stacker 25 by a drive system (not shown) and transferred to the conveyance roller 21f.
The paper is then transferred to the transfer unit 17 again via the paper transport path 16i. After a new color image is transferred to the paper in the second development process in the transfer section 17, the paper is transferred to the heat roller 18 along the paper transport path 16b and fixed again. Ru. The sheet fixed in this way is discharged from the paper transport path 16c to the paper discharge tray 20 via the paper discharge roller 19.

Finally, the case of double-sided copying will be explained with reference to FIG.

In the case of double-sided copying, the intermediate route differs depending on the directionality of the paper. First, as a frequently used paper conveyance path 16a to 16e116h, 16i, etc., the traveling direction is the longitudinal direction of the paper. In this case as well, the steps up to the first fixing step are the same as in the two types of copying examples described above.

For example, the paper P, on which the image rAJ has been transferred to one side (front surface) in the transfer unit 17, moves along the paper transport path 1 along the illustrated arrow f.
The surface is fixed by a heat roller 18 via 6b.

Thereafter, the paper transport path 1 is driven by the transport roller 21a.
6d, it is transferred to the first stacker 24 as shown by arrow q. In this first stacker 24, the paper P is kept on standby until a predetermined number of copies have been completed, but at this time the paper P has its back side facing up. Then, after placing the image to be copied on the back side on the original image placement section 11, copying is started again by a switch (not shown). Then, the paper P is first moved through the paper transport path 1 by a drive system (not shown).
The paper is fed by a pickup roller 28 provided in a direction perpendicular to the direction in which the paper is carried in from 6d, and is transported to the second stacker 25 along the first guide 26 as shown by the arrow and 1.
transported to. Here, when the paper P is transferred onto the second stacker 25 along the first guide 26, the paper P is turned from the back side to the front side again. That is, although the first guide 26 causes the sheet P to be turned over from the front side to the back side, the vertical positional relationship of the sheet P at that time remains unchanged.

Then, the paper P carried out from the second stacker 25 in the direction of the arrow j is transferred again to the transfer unit 11 in the direction of the arrow k via the paper carrying path 16e by the carrying roller 21f. However, at this time, the paper is sent to the transfer unit 17 so that the surface opposite to the surface on which rAJ is transferred, that is, the back surface, is in pressure contact with the photoreceptor drum 12, and the vertical positional relationship between the front and back surfaces of the paper is It is a match.

The paper P transferred with the same vertical positional relationship in this way is transferred from the paper transport path 16b to the heat roller 18 and fixed thereon, and then from the paper ejection roller 19 to the paper ejection tray via the paper transport path 16C. It is designed to be discharged to 20.

In addition, even in the case of double-sided copying, if the longitudinal direction of the paper is used in a direction perpendicular to the paper conveyance path, etc., the first The only difference is the transfer route of the paper P from the stacker 24 to the second stacker 25.

That is, the paper waiting in the first stacker 24 is fed by the pickup roller 31 provided in the same direction as the direction of transport into the paper transport path 16d.
It is conveyed to the second stacker 25 along the second guide 27. Then, the paper is transferred from the second stacker 25 to the transfer section 17 via the paper transport path 16i.

In this way, two
An image forming apparatus having two stackers 24 and 25 includes:
After one-sided copying is completed, the sheets are sequentially supplied from the first stacker 24 to the second stacker 25 to reverse the front and back sides of the sheets, and at the same time, the sheets with the front and back sides reversed are sequentially transferred to the transfer section 17. Since the information is transferred, the number of copies per unit time can be increased. Furthermore, in the case of double-sided copying, which is frequently used, in which the paper is set so that the longitudinal direction of the paper coincides with the direction of travel thereof, the vertical positional relationship between the front and back sides of the paper will match.

[Effects of the Invention] As described above, according to the present invention, efficiency is improved such as increasing the number of copies per unit time without requiring time for the copying process, and the front and back sides of the paper on which images are formed are improved. It is possible to provide an image forming apparatus in which the vertical positional relationship of the images corresponds to each other.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an image forming apparatus according to an embodiment of the present invention, FIG. 2 is an explanatory diagram showing the first stacker and second stacker in FIG. 1, and FIG. FIG. 4 is a schematic diagram of a conventional image forming apparatus, and FIG. 5 is an explanatory diagram showing the flow of double-sided copying in the apparatus shown in FIG. 4. 16a to 16i...Paper conveyance path, 17...Transfer section,
18... Heat roller, 24... First stacker, 25... Second stacker, 26... First guide, 27... Second guide. Applicant's agent Patent attorney Takehiko Suzue b Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Scope of Claims] An image forming means for forming an image according to image information on an image forming medium; a conveying means for conveying the image forming medium on which the image has been formed by the image forming means; a first and a second means for reversing the front and back sides of the image forming medium transported by the image forming means twice in order to re-image the image forming medium according to the type and returning the image forming medium to the image forming means; a first temporary storage means provided in the first feedback means and for temporarily storing the image forming medium; and a first temporary storage means provided in the second feedback means; a second temporary storage means provided in an opposing positional relationship, and the image forming medium temporarily stored from the first temporary storage means to the second temporary storage means is turned upside down. An image forming apparatus comprising: a moving means for moving the image forming apparatus.