JPH02178190A - Image former - Google Patents

Abstract

PURPOSE:To stack each sheet in page order by discharging the sheet that finished its image formation to either sheet container, where an image formed on one side comes to be turned to the bottom side, out of a first or second sheet container. CONSTITUTION:A sheet where a toner image is fixed by a fixing unit 10 and an image is formed at one side, is led into a combined paper discharge tray and turnover conveyor 13 on a body part 23 by paired discharge rollers 11, 12, and also guided to a first paper discharge tray 14 so as to turn the image to the bottom side, then it is stacked in page order at one side print. On the other hand, when a duplex print is the case, it is turned over in a direction orthogonal with the feed direction by a first turnover conveyor, to from the feeding direction by a second turnover part 17 and fed onto a second discharge tray 15, and further it is fed to the inside of the body 23 again from a second conveying means of the second turnover part 17 by way of a conveyor 21, thus an image is formed at the opposite side. Thus, the image is formed in the page order and can be stacked in pile in the same manner.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image forming apparatus such as a copying machine or a printer, and particularly to an apparatus that automatically forms images on both sides of a sheet.

In a conventional automatic double-sided image forming apparatus, an image is formed on one side of a sheet in the image forming section, and then the image is reversed (reversing means reversing the front and back sides of the sheet) and the sheet is fed again to the image forming section. There is a need. In this case, in order to make the image easy to view, the image must be formed so that the image on one side and the image on the opposite side are aligned in both the vertical and horizontal directions.

For this reason, conventionally, a method has been used in which a sheet with an image formed on one side is switched banked to change the front-back direction of the sheet and then reverse it. However, with this method, if image information is formed in the sheet feeding direction, it is possible to form images that are aligned vertically and horizontally on both sides, but images are formed in the direction perpendicular to the sheet feeding direction. If it is, the images will not be aligned on the front and back of the sheet. As a result,
The feeding direction of the sheet will be restricted (for example, A4
(When forming a horizontally written image on size paper, it is necessary to feed the image horizontally), the width of the image forming apparatus needs to be widened, which results in an increase in the size of the apparatus.

On the other hand, there is a converting device that inverts the sheet so that the left and right sides of the conveyance direction are reversed during conveyance after an image is formed on one side, and a sheet that switches banks and reverses the sheet so that the front and back of the conveyance direction are reversed. An image forming apparatus having a converting device has been proposed (see Japanese Patent Application Laid-Open No. 172162/1983). Since a device for switching back is required, an extra conveyance path and space for switching back are required.

In addition, in single-sided and double-sided image formation, the sheet surface after image formation is reversed, so if the sheets are ejected as is, the sheets will not be stacked in page order, and in both single-sided and double-sided image formation, the sheets will not be stacked in page order. To stack,
A special reversal switching mechanism is required in the discharge path,
There is a problem that the device becomes larger.

Furthermore, in such devices, since the reversal is performed in an intermediate tray inside the device, it is not possible to visually confirm the image formed on one side, and in double-sided image formation, the first image on one side is Since the sheets are stacked in a stacked manner, the driver has to use his/her hands to visually check this.

On the other hand, in a recording device, when a sheet with an image formed on one side is reversed in the feeding direction and conveyed to the image forming section again to form an image on the back side, the image for that page is transferred from the downstream side in the opposite direction. A device has also been proposed that aligns the vertical direction of images when double-sided recording is performed (Japanese Patent Laid-Open No. 62-18
6277, 62-265672 to 265676).

However, such a device requires the provision of a reverse memory.

In addition, with conventional image forming apparatuses, in order to perform so-called job separation, in which sheets with different types of images are separated and stacked, a dedicated device is required for this purpose. It was not possible to achieve this goal.

Problem to be Solved by I'1 The present invention solves the above-mentioned problems in the prior art.The invention as claimed in claim 1 provides a method for printing images in page order in both single-sided and double-sided image formation. An object of the present invention is to provide an image forming apparatus that can form images and stack them in the order of pages. To provide an image forming device capable of forming a double-sided image in which image information is aligned in the same direction for an image on one side and an image on the opposite side for images in both the feeding direction and the direction perpendicular thereto. The invention according to claim 3 provides, in addition to the problem of the invention according to claim 2, an image forming apparatus equipped with a job separate mode in which discharged sheets can be separated and stacked. The task is to do so.

In order to solve the above-mentioned problems, the present invention has an image forming unit that forms an image on a fed sheet and discharges the sheet, and then the sheet on which an image has been formed on one side is again printed with the image on one side. In an image forming apparatus that conveys to a forming section and forms an image on the opposite side, the invention according to claim 1 provides: a first sheet container for receiving the sheet on which an image is formed and the sheet to be discharged; a second sheet container for receiving the sheet; a first Vi feeding means for inverting and guiding the sheet from the first sheet container to a second sheet container; and a second conveyance means for guiding the sheet on which the image has been formed, either of the first or second sheet container, in which the image formed on the one side faces the bottom side of the container. The invention according to claim 2 is characterized in that the sheet is discharged into a sheet container including a first sheet container that receives the sheet on which an image is formed and is discharged, and a second sheet container that receives the sheet that has been guided to the first sheet container. a sheet container, a 1yIi conveying means for inverting and guiding the sheet from the first sheet container to a second sheet container, and a second conveying means for inverting and guiding the sheet from the second sheet container to the image forming section. The 11th Il transporting means has a longitudinal reversing transporting means for reversing the sheet in the direction of receiving and transporting the sheet;
4. The apparatus according to claim 3, further comprising: a lateral reversing conveyance means for reversing the sheet in a direction perpendicular to the receiving and feeding direction of the sheet, and the reversing direction is selected depending on the direction of the image formed on the sheet. In addition to the invention of claim 2, the invention provides that the vertical reversal conveyance means selectively stops conveyance of the sheet at a plurality of positions in a direction in which the sheet is received and conveyed within the first or second sheet container. and the horizontal reversal conveyance means,
The stopped sheet is conveyed in a direction perpendicular to the receiving and feeding direction, and the sheet is discharged into the first sheet container or the second sheet container.

According to the invention of claim 1, first and second IJIi transport means and first and second sheet containers are provided, and the sheet on which image formation has been completed is transferred to one of the first and second sheet containers. Since the sheet is ejected to one of the sheet containers in which the image formed on one side faces the bottom side of the container, for example, in an apparatus that forms an image on the top side of the sheet, in the case of single-sided image formation, By discharging the sheets into one sheet container and, in the case of double-sided image formation, discharging the sheets into a second sheet container, the sheets can be stacked in page order in any image formation.

According to the invention of claim 2, the first and second sheet conveying means and the first and second sheet containers are provided, and the first conveying means is a longitudinal reversing conveying means for reversing the sheet in the sheet feeding direction and the direction perpendicular to the sheet feeding direction. and a horizontal inversion conveyance means, so that one of the conveyance means is selected in accordance with the direction in which image information is formed, and the sheet is reversed and fed from the second sheet container to the image forming section by the second conveyance means. By feeding, it is possible to form vertically and horizontally aligned images in both the sheet feeding direction and the direction perpendicular thereto, without switching back during this period.

In the invention of claim 3, in addition to the above, the sheets are selectively stopped at a plurality of positions in the feeding direction within the first or second sheet container by the vertical reversing conveying means, and the sheets are stopped at a plurality of positions in the feeding direction by the horizontal reversing conveying means. Since the discharged sheets are stacked in the first or second sheet container, there is no need to provide a dedicated device for job separation.

χ-Example-1 FIG. 1(a) is a longitudinal sectional view showing an example of an image forming apparatus to which the present invention is applied. 1 and 2) show that the image forming apparatus of FIG. 1(a) is configured to be dockable by three units: an upper part, a main body part 23, and a lower part.

In this embodiment, the image forming section includes a charger 5 disposed around the photoreceptor drum 4, a laser beam writing device 6, a developer 7,
Transfer charger 8, cleaning device 9, and fixing device l
It is composed of O1 paper feed trays I and 2, registration rollers 3, paper discharge rollers 11, 12, 21, and the like.

The sheets fed from the paper feed tray I or 2 are timed by the registration rollers 3 and are transferred to the photoreceptor drums 4.
The image is transported to the transfer unit.

The latent image formed on the photosensitive drum 4 by the laser beam writing device 6 is developed as a toner image by the developing device 7, and after the toner image is transferred onto the sheet being fed by the transfer charger 8, The fixing device 10 heats and fixes the image.

A sheet with a fixed toner image and an image formed on one side is
The sheet is reversely conveyed by the paper rollers 11 and 12 and the conveyance path therebetween, and guided to the paper discharge tray/reverse conveyance device I3 at the upper part of the main body section 23. This device 13 includes a first sheet container,
The second sheet container and the second sheet conveying means each include a first discharge tray 14, a second sheet discharge tray 15, and a first reversing conveyance device 16 (see FIG. 2).

The sheet guided to the first paper discharge tray 14 is reversed from the direction perpendicular to the feeding direction within the first reversing conveyance device 16, or is reversed from the sheet feeding direction via the second reversing section 17, It is conveyed onto the second discharge tray 15. The second reversing unit 17 tilts the transport rollers 18, 19 and the switching guide 20, which are also part of the 11th Ic transport means, and among these, the transport roller 19 and the switching guide 20 constitute a part of the 211th transport means as an example. do. This second reversing section 17
The sheet on the second paper discharge tray 15 is conveyed to the inside of the main body section 23 via the conveyance roller 21 by the second vIi conveyance means, and an image is formed on the opposite side.

In the above-described operation, in this embodiment, the first paper ejection tray 14 is a tray for stacking ejected paper on pages in single-sided printing, and the second paper ejection tray 15 is used for single-sided printing, with the printed side facing up. It is used as a discharge tray for stacking sheets in the form of paper sheets and as a tray for stacking discharged sheets in pages for double-sided printing, and these selections are made by mode control of the print signal.

Note that the paper ejection tray/reversing conveyance device 13 and the second reversing section 1
7 can be tonked to the main body part 23 as a unit. When the sheet feeding reference of the main body section 23 is the central reference, the second reversing section 17 is fixed with respect to the main body section 23, and the paper ejection tray/reversing conveyance device 13 is set relative to the main body section 23. It can also be constructed so that the position can be moved in a direction perpendicular to the sheet feeding direction in accordance with the sheet size (FIG. 2 shows that it is movable by a length l).

FIG. 2 shows a cross section of the paper discharge tray/reversing conveyance device 13 (an axial cross section of the paper discharge roller I2).

The first reversing conveyance device 16 of the device 13 has a vertical reversing conveying means for reversing the sheet from the feeding direction and a horizontal reversing conveying means for reversing the sheet from a direction perpendicular to the feeding direction, and FIG. 2 shows the main parts of these. An example is shown.

The transport belt 24, which is part of the vertical reversal means, is a rubber belt arranged in Pulley 33.34 (see Fig. 3 (A)), and the upper and lower surface is a solenoid device.
A pivoting guide 25, 28 driven by 29 is brought into selective contact.

? The surfaces of the L movement guides 25 and 28 are coated with a low friction material such as Teflon. Also, the friction guide 25.
The opposite end of the conveyor belt 24 at 28 selectively contacts the surface of a conveyor roller 27,30 forming part of the transversal conveyor means.

In addition, in FIG. 1(a) and FIG. 2, the first and second
The feeding means section 111i is configured to be able to open the conveyance path in the directions of arrows A, B, and C, making it easy to clear sheets from jams.

FIG. 3(a) is a longitudinal sectional view including the conveyor belt 24,
FIG. 3) is a perspective view of the conveyor belt 24.

The sheet conveyed from the paper ejection roller 12 is transferred to the conveyor belt 2
It is sandwiched between the 4% and 1% moving guides 25 and conveyed in the feeding direction (rightward in the figure).

When the leading edge of the sheet is detected by the sensor 36, the solenoid 26 is attracted and the conveyor belt 24 is driven by the motor 35. The motor 35 stops a predetermined time after the rear end of the sheet is detected by the sensor 36.

4(a) to 4(d) show a method for reversing and conveying a sheet from the first ejecting tray 14 onto the second ejecting tray 15 from a direction perpendicular to the sheet feeding direction using a horizontal reversing conveying means. 1. The method of discharging paper into the second Haigi tray 14 and 15 is shown.

FIG. 4(a) shows that the sheet is placed on the conveyor belt 2 as described above.
4 shows a state in which the conveyor belt 24 has stopped after being conveyed by the conveyor belt 24. In this state, the conveyance roller 27, which forms part of the horizontal reversal conveyance means, and the Ti motion guide 25 are not in contact with each other.

FIGS. 4 and 4) show a state in which a sheet is being reversely conveyed from the first discharging tray 14 to the second discharging tray 15. The solenoid device 26 is released, and the friction guide 25 is released from contact with the conveyance belt 24 by a spring (not shown) and comes into contact with the conveyance roller 27 . Simultaneously with the release of the solenoid 26 or after a predetermined period of time, the conveying roller 27 is driven to rotate in the direction of the arrow in the figure, and the sheet passes through the reversing guide 31 and its leading edge reaches the nip between the conveying roller 30 and the friction guide 28. The sheet reaches the nip portion for a predetermined period of time to correct the skew of the sheet. This operation is performed by detecting the leading edge of the sheet by the sensor 38 and controlling the drive timing of the conveying roller 30.

Next, when the sheets are discharged from this state into the second tray 15 and stacked, the conveying roller 30 is stopped after the trailing edge of the sheet passes the sensor 38 and is discharged and stacked on the tray 15. Control.

FIG. 4(C) shows a state in which the sheet is not discharged onto the second reversing tray 15 and is further conveyed from the second reversing section 17 to the main body section 23 of the apparatus. After the trailing edge of the sheet passes the sensor 3 days and is conveyed to a predetermined position on the conveyor belt 24, the paper ejection roller 30 is stopped, and at the same time or after a predetermined time, the solenoid 29 is sucked and the sheet is placed on the conveyor belt 24. make it stop. The subsequent operation will be explained with reference to FIG.

FIG. 4(d) shows the case where the sheets are returned to the first discharge tray 14 from the state shown in FIG. 4(b) and are stacked therein. After visually checking the image formed on one side of the sheet on the second ejecting tray 15-1, the conveying roller 3
By rotating the 0.27 in the opposite direction, the sheet can again be guided onto the second output tray 14 and stacked therein.

Next, FIG. 5(a) shows a case where the sheet is reversed and conveyed from the first paper tray 14 to the second paper discharge tray 15 from the feeding direction side by the vertical reversal conveyance means.

The sheet conveyed from the paper ejection roller 12 is transferred to the conveyor belt 2
4 and the friction guide 25 to the conveyance roller 18, and from there, it is conveyed to the conveyance roller 19 via the reversal switching guide 20 section.
The paper is conveyed onto the second paper discharge tray 15 by the following. Here the second
When stacking sheets in the paper tray 15, the conveyor belt 24 conveys the sheets to a predetermined position as shown in FIG. 4(C).
8 and rotate the conveyance roller 30 counterclockwise in the figure.

FIG. 5(b) shows a case where the sheet on the second loitering tray 15 is reversely conveyed to the main body section 23 again. Conveyance roller 18
, the sheet is conveyed onto the second discharge tray 15 by the reversal switching guide 20 and the conveyance roller 19, and after the trailing edge of the sheet passes the sensor 39, the reversing switching guide 20 is moved to the state shown in FIG. 5(a) by a solenoid (not shown). to the state shown in FIG. 5(b), and at the same time the transport roller 19 and the transport belt 2
4 is reversely rotated, the sheet is conveyed, reversed and fed to the main body section 23. Even when the paper is reversely fed from the state shown in FIG. 4(C), the operations after switching of the reversal switching guide 20 are performed.

FIGS. 6(a), 6(a), and 6(c) are explanatory views when executing a job separate mode in which discharged sheets are sorted and stacked by sheet type.

The conveyor belt 24 is detected by the sensor 36 shown in FIG. 3(a).
As shown in FIG. 6(a), depending on the type of information, for example, the conveyor belt 24 can be moved in the feeding direction A, B, or
Stop the seat at any position C, and then
) As shown in FIG. 6(C), after releasing the solenoid 26 and sandwiching the sheet between the friction guide 25 and the conveying roller 27, the conveying roller 27 is rotated in the direction of the arrow for a predetermined period of time. As shown in ↑WWi, sheets can be separated and stacked by type.The above example shows the case where sheets are stacked on the first paper output tray 14, but the fourth
By performing the same operation from the state shown in figure (C), the second
The job separate mode can also be executed in the discharge tray 15.

In the above embodiment, the first paper discharge tray 14 and the second paper discharge tray 15 are arranged in two stacked layers, one above the other, and the vertically reverse conveying means and the horizontally reverse conveying means between these trays are used to separate the jobs. However, even in the case of an image forming apparatus with only one paper ejection tray, it is necessary to have a vertical conveying means that can set multiple positions in the sheet feeding direction and a sheet feeding direction perpendicular to the feeding direction. By providing a lateral conveying means for discharging sheets, it is possible to accurately separate and stack sheets at a plurality of positions on the conveying direction side, thereby performing job separation.

FIGS. 7 and 8 are diagrams showing the order in which double-sided images are formed by the image forming apparatus of this embodiment, and show the case where the images are reversed by a horizontal reversing conveyance means and a vertical reversing conveyance means, respectively. The selection of the horizontal reversal conveyance means and the vertical reversal conveyance means is made in accordance with the direction of the image formed on the sheet. That is,
When forming an image in a direction perpendicular to the sheet feeding direction (for example, when forming an image to be written horizontally on an A4 size sheet by vertically feeding the sheet), use a horizontal reversing conveyance means to form an image in the direction perpendicular to the sheet feeding direction. (for example, A4
When an image to be written horizontally on a size sheet is formed by horizontally feeding the sheet, a vertically reversing conveying means is used.

In FIG. 7(a), an image in a direction perpendicular to the feeding direction is formed on one side of the sheet fed to the image forming section (step l), and this sheet is placed on the first ejecting tray 14. (Step 2). Next, the sheet is reversely conveyed from the first discharge tray 14 to the second discharge tray 15 by the horizontal reversal conveyance means (step 3), and further conveyed by the second conveyance means, reversed, and fed again to the image forming section. (Step 4). Then, as shown in FIGS. 7 to 7), an image is formed on the opposite side (step 5) to complete a double-sided image, which is then reversely conveyed from the first discharging tray 14 to the second discharging tray 15, and then transferred to the second discharging tray 15. The sheet is discharged into the tray 15 with the first side on which the first image is formed facing down (step 6). FIG. 7(C) shows a state where up to the sixth page has been printed and discharged and stacked in this manner.

With such an operation, it is possible to form an image in which the image directions are aligned both vertically and horizontally on one side and the opposite side with respect to image information in the direction perpendicular to the sheet feeding direction, and also in double-sided printing. Sheets can be discharged and stacked on page Jl. Furthermore, if the inside of the second locomotive tray 15 is configured to be visible, the state of the sheet printed on one side can be visually recognized when it is conveyed, and after the double-sided image is formed, the state of the sheet is discharged and stacked. Since the print status on the opposite side can be visually confirmed, operability is improved.

When producing a print on only one side, please refer to Figure 7 (a).
) After step 2 is completed, the sheets can be stacked in page order by stacking the sheets in the first paper tray 14. Also, in this case, Fig. 4(d)
As explained in , for example, once the first page sheet is
By transporting the sheets to the paper output tray 15, checking the image surface 1111 there, and stacking the output sheets again in the first paper output tray 14, the driver can check the copy status without bothering the driver. . Furthermore, by controlling the print mode, it is also possible to stack single-sided printing on the second paper discharge tray 15 with the printed side facing up.

If printing is completed for each sheet as described above, compared to the method of printing only on the negative side and stacking the sheets on the intermediate tray, problems such as page 1 ejection being disrupted when a jam occurs can be eliminated.

Note that if double-sided image formation is performed using the method described above, A4
In the case where an image is written horizontally in the short side direction of a standard size such as the above, the width of the device can be made small, thereby preventing the device from increasing in size.

FIG. 8 shows a case where image information is formed in the sheet feeding direction, and a double-sided image is formed by reversing the sheet from the feeding direction. The image forming order is the same as in the case of FIG. 7, so the explanation will be omitted.

In this case as well, it is possible to visually check the image surface in either one-sided or double-sided image formation, and the sheets can be stacked in page order, and the sheets can be aligned vertically and horizontally on one side and the opposite side. You can obtain a clear image.

According to this method, for example, when a horizontally written image is formed on an A4 size sheet in the short side direction,
By horizontally feeding this sheet to form an image, the time required for image formation in a copying machine or the like is shortened.

In the image forming apparatus of this embodiment described above, the first haishi tray 1
4. The second paper ejection tray 15 and the like are arranged above the main body part 23, but by doing so, the sheet conveyance system can be shortened and simplified.
Since the tray is opened, it becomes easier to visually check the inside of the tray.

In addition, in this embodiment, the first discharge tray 14 is placed on the lower stage, and the second
Although the paper ejection tray 15 is arranged on the upper stage, in an image forming apparatus that transfers the image to the lower surface of the sheet above the photoreceptor 4, for example, the first ejecting tray is arranged on the upper stage and the second ejecting tray is arranged on the lower stage. The present invention can be applied in the same manner and the same effect can be obtained by arranging it in .

Effects of the Invention As described above, according to the present invention, in the invention of claim 1, first and second sheet containers and first and second conveying means are provided, and the sheet on which image formation has been completed is carried so that the image forming surface thereof is Since the sheets are finally discharged to the sheet container facing the bottom side, the sheets can be discharged and stacked in page order for either single-sided or double-sided images, and in the invention of claim 2, Vertical reversal or horizontal reversal is selected using the vertical reversal conveyance means and the horizontal reversal conveyance means, and the first
Reversely convey the sheet from the sheet container to the second sheet container,
Since the sheet is reversely fed from the top of the second sheet container to the image forming unit by the second conveyance means, images that are aligned vertically and horizontally on both sides of the double-sided image are formed without providing a switchback device in the conveyance path. In the invention of claim 3, in addition to the above, by providing a job separation mode, job separation can be performed without providing a dedicated device.

[Brief explanation of the drawing]

The drawings all show embodiments of the present invention, and FIG. 1 (August) is a vertical sectional view of the image forming apparatus, FIG. 3(a) is a vertical sectional view including the conveying belt portion, FIG. 3(b) is a perspective view of the conveying belt, and FIG. 4(a) is a cross-sectional view of the reversing conveyance device.
5(a) and 5(b) are explanatory diagrams of vertical reversal and reversal conveyance to the image forming section, and FIG. 6(a) is an explanatory diagram of horizontal reversal.
6(b) is a longitudinal sectional view thereof, FIG. 6(C) is a diagram showing the stacked state of the discharged sheets, and FIGS. FIG. 8 is an explanatory diagram showing the order of double-sided image formation. 13... Paper discharge tray and reversing conveyance device (first and second sheet containers, first conveyance means) 14... First loitering tray (first sheet container) 15... Second loitering Paper tray (second
sheet container) 16... first reversing conveyance device (first conveying means) 17... second reversing section (second conveying means) 18.
-... Conveyance roller (part of vertical reversal conveyance means) 19...
- Conveyance roller (part of the vertical reversal conveyance means and part of the second conveyance means) 20...Switching guide (part of the second conveyance means) 23.
... Main body (image forming section) 24... Conveyor belt (part of the vertically reversing conveying means and part of the second conveying means) 25.28-... Friction guide (vertical/horizontal reversing 2G, 29... Solenoid device (part of the vertical/horizontal reversing conveying means) 27.30... Conveying roller (part of the horizontal reversing conveying means) 31... Reversing Guide (part of horizontal reversal conveyance means) (1 idiot) Figure (b) Figure (a) (b) 2nd (c) (d) Figure q (C)

Claims (3)

[Claims] (1) Image forming in which an image is formed on one side of the sheet in an image forming unit that forms an image on a fed sheet and discharges the sheet, and then conveys the sheet again to the image forming unit to form an image on the opposite side. In the apparatus, a first sheet container receives the sheet to be imaged and discharged, a second sheet container receives the sheet guided to the first sheet container, and the sheet is transferred from the first sheet container to a second sheet container. a first conveyance means that inverts and guides the sheet to a container; and a second conveyance means that inverts and guides the sheet from the second sheet container to the image forming section; Alternatively, the image forming apparatus is characterized in that the sheet is discharged to any one of the second sheet containers in which the image formed on the first side faces the bottom side of the container. (2) Image formation in which an image is formed on a fed sheet and an image is ejected from the image forming section, and the sheet with an image formed on one side is conveyed again to the image forming section and an image is formed on the opposite side. In the apparatus, a first sheet container receives the sheet to be imaged and discharged, a second sheet container receives the sheet guided to the first sheet container, and the sheet is transferred from the first sheet container to a second sheet container. a first conveyance means that inverts and guides the sheet to a container; and a second conveyance means that inverts and guides the sheet from the second sheet container to the image forming section, the first conveyance means receiving and conveying the sheet. The image forming apparatus includes a vertical reversing conveying means for reversing the sheet in a direction, and a horizontal reversing conveying means for reversing the sheet in a direction perpendicular to the direction in which the sheet is received and fed, and the sheet is reversed according to the direction of the image formed on the sheet. An image forming apparatus characterized by selecting a direction. (3) The vertically reversing conveying means selectively stops conveying the sheet at a plurality of positions in the receiving and feeding direction of the sheet in the first or second sheet container, and the horizontally reversing conveying means 3. The image forming apparatus according to claim 2, wherein the stopped sheet is conveyed in a direction perpendicular to the receiving and feeding direction, and the sheet is discharged into the first sheet container or the second sheet container.