JPH08202096A - Image forming device - Google Patents

Abstract

(57) [Summary] [Purpose] The probability of occurrence of jam is low, the time for paper passing is short, and there is no drop in fixing temperature.
An object is to provide an image forming apparatus that can save space. [Structure] OHP sheet 18 on first paper feed tray 16
An image forming unit 9 including a first paper feeding unit 22 for feeding the sheet and a transfer unit 7 for transferring the formed image to the OHP sheet 18.
A fixing unit 11 for fixing the image transferred by the transfer unit 7 onto the OHP sheet 18, a paper discharging unit 14 for discharging the OHP sheet 18 or the interleaf sheet 19, and the first paper feeding unit 22. A transfer paper transport path 23 for transporting the OHP sheet 18 from the transfer unit 7 to the paper discharge unit 14 through the transfer unit 7 and the fixing unit 11, and a interleaf sheet 19 on the second paper feed tray 17. The second paper feed unit 28 and the interleaf sheet conveyance path 29 for directly conveying the interleaf sheet 19 from the second paper feed unit 28 to the paper ejection unit 14 are provided.

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 such as a copying machine.

[0002]

2. Description of the Related Art OHP sheets (over head projector sheets) are formed of a transparent synthetic resin sheet or film, and are usually used in copying machines to copy image information for meetings, research presentations, briefing sessions, etc. Used as a slide manuscript. When a plurality of OHP sheets are stacked, it is usually necessary to sandwich a soft thin paper called an interleaving sheet (interleaving sheet) between the OHP sheets for surface protection.

However, when a plurality of OHP sheets on which an image is formed are stacked on the discharge tray, it is very efficient to manually insert the interleaving sheets between the OHP sheets. Is bad.

Therefore, conventionally, there is an image forming apparatus capable of automatically performing such work. This image forming apparatus is provided with an OH
The P sheet is stacked, and the interleaf sheet is stacked in one of the other paper feed trays. Then, the OHP sheet and the interleaving sheet are alternately fed and sequentially transported on the transfer sheet transport path to the transfer section, the fixing section, and the discharge tray. At this time, the transfer unit transfers the image only to the OHP sheet.
In the fixing unit, the image transferred on the OHP sheet is fixed. Therefore, the OHP sheet on which the image is formed and the interleaf sheet on which the image is not formed are alternately discharged onto the discharge tray.

[0005]

However, in the above-described image forming apparatus, since the interleaf sheet stacked on the paper feed tray is conveyed through the transfer section and the fixing section along the transfer sheet conveying path, there is a probability that a jam will occur. Becomes higher. Also, in the fixing unit,
Heating and pressing are performed without distinction between the HP sheet and the interleaf sheet. Therefore, every time the interleaf sheet is conveyed, the heat of the fixing unit is taken away by the interleaf sheet. Furthermore, since the interleaf sheet is conveyed through the same conveyance path as the OHP sheet, the time during which the interleaf sheet is conveyed (usually, the time when an image can be formed on the transfer sheet) is wasted.
There is a problem of low productivity.

On the other hand, there is an interleaf sheet supply device for an OHP sheet as disclosed in Japanese Utility Model Laid-Open No. 5-75252. This supply device is a device separate from the image forming device, and includes a paper feed tray on which interleaf sheets are stacked. Then, the OHP sheet discharged from the sheet discharge port of the image forming apparatus and the interleaf sheet are superposed in the supply device, and are discharged to the discharge tray of the supply device.

As a result, since the interleaf sheet is not conveyed through the transfer section and the fixing section, it is possible to reduce the probability of occurrence of jam and shorten the time during which the sheet can be passed. it can. Furthermore, since the heat of the fixing unit is not taken away by the interleaf sheet, it is possible to save energy and prevent the fixing temperature from dropping.

However, since the feeding device disclosed in Japanese Utility Model Laid-Open No. 5-75252 is a device separate from the image forming apparatus, it cannot save space.

The present invention has been made in view of the above problems, and has a low probability of jamming, a short time in which a sheet can be passed, a fixing temperature does not drop, and a space is saved. It is an object of the present invention to provide an image forming apparatus capable of performing the above.

[0010]

According to the first aspect of the present invention,
First feeding of transfer sheets stacked on the first feeding tray
Sheet feeding section, an image forming section including a transfer section that transfers the formed image to the transfer sheet, a fixing section that fixes the image transferred by the transfer section onto the transfer sheet, and a transfer sheet or slip sheet. A sheet discharging section for discharging the sheet, a transfer sheet conveying path for conveying the transfer sheet from the first sheet feeding section to the sheet discharging section through the transfer section and the fixing section, and a second sheet feeding tray. A second paper feed unit for feeding the interleaf paper stacked thereon and a interleaf paper conveyance path for directly conveying the interleaf paper from the second paper feed unit to the paper ejection unit are provided. It was

According to a second aspect of the present invention, the second sheet feeding tray in the image forming apparatus according to the first aspect is placed on the same horizontal plane as the first sheet feeding tray having a small size corresponding to the transfer sheets to be stacked. It was installed in parallel.

According to a third aspect of the present invention, there is provided a double-sided conveying path for reversing the transfer sheet having passed through the fixing section and conveying it again to the transfer section through the interleaving sheet conveying path in the image forming apparatus according to the first or second aspect. It was formed by also using a part.

[0013]

According to the first aspect of the invention, since the interleaf sheet conveying path is provided in the main body of the image forming apparatus, it is not necessary to provide a peripheral device for interleaving the interleaf sheet outside the main body, thus saving space. In addition, since the interleaf sheet is not conveyed through the transfer section and the fixing section, the probability of occurrence of a jam is reduced and the time during which the sheet can be passed is shortened. Since the sheet does not take heat from the fixing section, energy saving is realized and the fixing temperature is prevented from dropping.

According to the second aspect of the present invention, the second paper feed tray is provided in an unused space next to the small-sized first paper feed tray, so that further space saving is realized. .

According to the third aspect of the present invention, a part of the double-sided conveying path is also used as the interleaf sheet conveying path, so that further space saving and cost reduction can be realized.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. The image forming apparatus of the present embodiment is applied to the copying machine 1, and the photosensitive drum 2 is provided in the central portion of the copying machine 1. Around the photosensitive drum 2, a charging device 3, a developing device 4, a transfer separator 5, and a charge eliminator 6 are provided according to an image forming process. A transfer portion 7 is formed by the photosensitive drum 2 and the transfer separator 5.
Further, between the charging device 3 and the developing device 4, there is formed an exposed portion 8 for exposing the photosensitive drum 2 by a scanner optical system described later. An image forming section 9 is formed by the photoconductor drum 2, the charger 3, the exposed portion 8, the developing device 4, the transfer separator 5 and the static eliminator 6. A pair of fixing rollers 10 is provided on the downstream side of the transfer section 7 (leftward in FIG. 1), and a fixing section 11 is formed. A paper discharge roller 12 is provided on the downstream side of the fixing roller 10. The copying machine 1 on the downstream side of the paper discharge roller 12
A discharge port (not shown) is formed on the side surface. A paper discharge tray 13 is supported below the paper discharge port.
The paper discharge roller 12, the paper discharge port, and the paper discharge tray 13 form a paper discharge unit 14. A paper discharge detection sensor 15 is provided between the paper discharge roller 12 and the paper discharge port.

In the lower part of the copying machine 1, four stages of paper feed tray insertion openings (not shown) are formed. At the top of these paper feed tray insertion openings, a small-sized paper feed tray 16 that is the first paper feed tray and a paper feed tray 17 that is the second paper feed tray are inserted in parallel. . Transfer paper OHP sheets 18 are stacked on the paper feed tray 16, and interleaving paper sheets 19 are stacked on the paper feed tray 17. Further, a paper feed tray 21 on which the transfer paper 20 is stacked is inserted in the lower three stages of the paper feed tray insertion opening. A sheet feeding device 22 as a first sheet feeding unit is provided on the side of the photosensitive drum 2 of each of the sheet feeding trays 16 and 21.

Further, the copying machine 1 includes the paper feeding device 22.
From the OHP sheet 18 or the transfer paper 20 to the paper discharge unit 14 through the transfer unit 7 and the fixing unit 11.
A transfer paper transport path 23 for transporting the sheet is formed. In addition,
A registration roller 24 is provided on the transfer paper transport path 23 in front of the transfer section 7.

A reversing device 26 having a tray 25 is provided below the fixing section 11. And
A double-sided conveyance path 27 is formed to convey the transfer paper 20 from the paper discharge unit 14 to the transfer unit 7 through the reversing device 26.

A sheet feeding device 28, which is a second sheet feeding section, is provided on the sheet ejection tray 14 side of the sheet feeding tray 17. An interleaf sheet conveyance path 29 for directly conveying the interleaf sheet 19 from the paper feeding device 28 to the paper ejection unit 14 is formed. This interleaf sheet conveyance path 29 is
A part of the double-sided conveyance path 27 is also used above the reversing device 26.

A first switching claw 30 is switchably provided at a branch point between the transfer paper transport path 23 and the double-sided transport path 27 between the paper discharge section 14 and the fixing section 11. ing. A second switching claw 31 is switchably provided at a branch point between the double-sided transport path 27 and the interleaf sheet transport path 29.

Further, a contact glass 32 is fixed on the upper portion of the copying machine 1. A document pressing plate 34 having an automatic document feeder 33 is provided on the contact glass 32. A scanner optical system 35 is provided below the contact glass 32.

In such a structure, the OHP sheet 1
A description will be given of the operation of copying an image on the image recording medium 8. First,
The scanner optical system 35 scans the document sequentially conveyed by the automatic document feeder 33 and placed on the contact glass 32, and the photoconductor drum 2 is charged by the charger 3. Then, in the exposed portion 8, the photoconductor drum 2 is exposed by the scanner optical system 35 in accordance with the image of the original, and an electrostatic latent image is formed. This electrostatic latent image is developed by the developing device 4. In parallel with this, the OHP sheet 18 is fed by the paper feeding device 22 and is conveyed on the transfer paper conveying path 23 to the transfer section 7. At this time, the OHP sheet 18 is conveyed according to the image on the photoconductor drum 2 by the registration roller 24, and the image on the photoconductor drum 2 is transferred by the transfer unit 7. After that, it is conveyed to the fixing unit 11 and heated and pressed by the fixing roller 10. This allows
The image is fixed on the OHP sheet 18. Further, the photoconductor drum 2 is destaticized by the destaticizer 6 after the image is transferred to the OHP sheet 18.

After that, the OHP sheet 18 is conveyed along the transfer sheet conveying path 23. At this time, the first switching claw 3
0 is switched, and the transfer paper transport path 23 from the fixing unit 11 to the paper discharge unit 14 is selected. And OHP sheet 1
8 is conveyed to the paper output unit 14. Therefore, OHP sheet 1
The reference numeral 8 designates a discharge tray 12 from a discharge port by a discharge roller 12.
It is ejected on top.

At this time, the paper discharge detection sensor 15
When the OHP sheet 18 is detected, the paper feeding device 28 operates and the interleaf sheet 19 is fed from the paper feeding tray 17.
At this time, the first switching claw 30 and the second switching claw 31 are switched to select the interleaf sheet conveyance path 29 from the paper feeding device 28 to the paper ejection unit 14. And the interleaf sheet 19
Is immediately conveyed to the paper discharge unit 14 along the interleaf sheet conveyance path 29. Therefore, the interleaving sheet 19 is used for the paper ejection roller 12
As a result, the sheets are stacked on the OHP sheet 18 discharged from the discharge port to the discharge tray 13.

Further, when the paper discharge detection sensor 15 detects the interleaving paper sheet 19, the document arranged on the contact glass 32 is scanned by the scanner optical system 35 and corresponds to the paper feed tray 16. The paper feeding device 22 operates to feed the OHP sheet 18, and an image is formed on the OHP sheet 18 in the same manner as the above-described operation.
The sheets are stacked on the interleaf sheet 19 stacked on the discharge tray 13.

It should be noted that the above-mentioned document is a desired number of OHP sheets.
After the sheet 18 is copied, it is conveyed by the automatic document feeder 33 and discharged. At this time, if another document is set in the automatic document feeder 33, the same operation as the above-described operation is repeated to obtain the desired number of OHP sheets 1.
8 is copied, and the interleaf sheet 19 is sandwiched between the OHP sheets 18.

When forming images on both sides of the transfer paper 20 in the copying machine 1 as described above, first, the transfer paper 20 is fed from the paper feed tray 21 by the paper feed device 22.
The image is formed by being sequentially conveyed to the transfer unit 7 and the fixing unit 11 along the transfer paper conveyance path 23. Next, the first switching claw 30 and the second switching claw 31 are switched to select the double-sided transport path 27. Then, the transfer paper 20 having an image formed on one side is conveyed to the reversing device 26 along the double-sided conveyance path 27. By the reversing device 26, a desired number of transfer papers 20 are conveyed from the paper discharge unit 14 side to the tray 25 and stacked, and then the transfer papers 20 are transferred from the paper discharge unit 14 side of the tray 25 to one.
The transfer paper 20 is conveyed sheet by sheet and the front and back sides of the transfer paper 20 are reversed. Then, the transfer sheet is conveyed to the transfer sheet conveying path 23 below the photosensitive drum 2 along the double-sided conveying path 27. And
Again, the transfer unit 7 and the fixing unit 11 are provided along the transfer paper transport path 23.
Are sequentially transported to. As a result, images are formed on both sides. At this time, the first switching claw 30 is switched to select a part of the transfer paper transport path 23 from the fixing unit 11 to the paper discharge unit 14. Then, the transfer paper 20 is conveyed to the paper output unit 14. Then, the paper is discharged onto the paper discharge tray 13 from the paper discharge port by the paper discharge roller 12.

As described above, by providing the interleaf sheet conveyance path 29 in addition to the transfer sheet conveyance path 23, the interleaf sheet 1
Since the sheet 9 is not conveyed through the transfer unit 7 and the fixing unit 11, the probability of jamming is reduced. Further, the interleaf sheet 19 is conveyed to the fixing roller 10 and the fixing roller 1
It won't take the heat of zero. Therefore, energy saving can be achieved, and a drop in fixing temperature can be prevented. Furthermore, FIG.
As shown in FIG. 5, the distance between the discharged OHP sheets 18 is such that almost one interleaving sheet 19 is discharged. However, FIG. 2 shows the paper discharge detection sensor 1 when the interleaf sheet 19 is stacked on either the paper feed tray 16 or 21.
5 (A) and the paper discharge detection sensor 1 in this embodiment
5 is a comparison with the operation (B) of FIG. Further, since the paper feed tray 17 is provided in an unused space beside the small size paper feed tray 16, the space can be further saved. Further, the double-sided conveyance path 27 and the interleaf sheet conveyance path 29
Since it is also used as a part of, it saves more space and
Cost reduction.

Although the OHP sheets 18 are stacked on the paper feed tray 16 in this embodiment, the paper feed tray on which the OHP sheets are stacked is not limited to the paper feed tray 16 and other paper feed trays 21 may be stacked. It does not matter which OHP sheet 18 is stacked.

Further, the paper discharge detection sensor 15 conveys the interleaf sheet 19 by detecting the OHP sheet 18, and conveys the OHP sheet by detecting the interleaf sheet 19, but the OHP sheet 18 and Interleaf sheet 1
The method of setting the timing of conveying 9 is not limited to this method, and another method may be used as long as the OHP sheet 18 and the interleaving sheet 19 are alternately stacked on the discharge tray. For example, a transfer paper sensor (not shown) is provided in the transfer paper conveyance path 23, and an interleaving paper sheet sensor (not shown) is provided in the interleaf paper transfer path 29 so that the transfer paper sensor detects the OHP sheet 18. Then, the interleaf sheet 19 is conveyed, and when the interleaf sheet sensor detects the interleaf sheet 19, the OHP sheet 18 is conveyed and the OHP sheet 1 is placed on the ejection tray 13.
8 and the interleaf sheet 19 may be alternately stacked.

[0032]

According to the first aspect of the present invention, since the interleaf sheet conveying path is provided in the main body of the image forming apparatus, it is not necessary to provide a peripheral device for interleaving the interleaf sheet outside the main body. In addition, since the interleaving sheet is not conveyed through the transfer section and the fixing section, it is possible to reduce the probability that a jam will occur, and to reduce the time during which paper can be passed. Further, since the interleaving paper sheet does not take heat of the fixing unit, it is possible to realize energy saving and prevent the fixing temperature from dropping.

According to the second aspect of the present invention, the second paper feed tray is provided in an unused space next to the first paper feed tray having a small size. Therefore, further space saving can be realized. it can.

According to the third aspect of the present invention, a part of the double-sided conveyance path is also used as an interleaf sheet conveyance path, so that further space saving can be realized and cost reduction can be realized. You can

[Brief description of drawings]

FIG. 1 is a vertical sectional front view showing a copying machine using an embodiment of the present invention.

FIG. 2 is a time chart showing the operation of a paper discharge detection sensor.

[Explanation of symbols]

 7 Transfer Section 9 Image Forming Section 11 Fixing Section 14 Paper Ejection Section 16 First Paper Feed Tray 17 Second Paper Feed Tray 18, 20 Transfer Paper 19 Interleaf Sheet 22 First Paper Feed Section 23 Transfer Paper Conveying Path 27 Double-sided transport path 28 Second paper feed section 29 Interleaf sheet transport path

Claims (3)

[Claims] 1. A first sheet feeding section for feeding a transfer sheet stacked on a first sheet feeding tray, and an image forming section including a transfer section for transferring an image formed image onto the transfer sheet. A fixing unit for fixing the image transferred by the transfer unit onto the transfer paper, a paper discharge unit for discharging the transfer paper or the interleaving sheet, and a transfer unit and the fixing unit from the first paper supply unit. A transfer sheet conveying path for conveying the transfer sheet to the sheet discharging section, and a second sheet feeding section for feeding the interleaf sheet stacked on the second sheet feeding tray,
An image forming apparatus comprising an interleaving sheet conveying path for directly conveying the interleaving sheet from the second sheet feeding section to the sheet discharging section. 2. The image according to claim 1, wherein the second paper feed tray is provided in parallel on the same horizontal plane as the first paper feed tray of a small size suitable for the transfer paper to be stacked. Forming equipment. 3. The interleaf sheet conveyance path is formed so as to also serve as a part of a double-sided conveyance path for reversing the transfer sheet that has passed through the fixing section and conveying it again to the transfer section.
The image forming apparatus described.