JPH0725535A - Electrophotography device - Google Patents

Abstract

PURPOSE:To provide an electrophotography device by which the speed of fast printing can be improved. CONSTITUTION:When printing wherein the number of print paper sheets by printing information from a host computer is one or less is performed, a driving part 37 is automatically driven before a paper sheet 21 reaches a switching member 31, so as to make the face-up state wherein a conveyance passage is short, and the switching member 31 connected to the driving part 37 is rotated around a switching member shaft 31b, so as to switch the state to the face-up state where the conveyance passage is short.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus such as a laser printer.

[0002]

2. Description of the Related Art In a general laser printer, it has become possible for a user to select whether to eject an image surface of a sheet in an upward (face-up) or downward (face-down) state by switching means such as a lever.

A conventional electrophotographic apparatus will be described below. FIG. 2 is a side view of the conventional electrophotographic apparatus in a face-down state.

In FIG. 2, reference numeral 1 denotes an image carrier having a resin belt such as polyethylene terephthalate as a base material and a photosensitive receiving layer such as selenium (Se) coated on its outer peripheral surface in a thin film form. The image carrier 1 is in the form of a belt, is banded by two image carrier transport rollers 2 and 3 arranged vertically, has a vertical plane between the image carrier transport rollers 2 and 3, and has a drive motor. By rotating the image carrier conveying rollers 2 and 3 by the above-mentioned operation, the image carrier convey rollers 2 and 3 rotate in the direction of arrow A. Further, on the peripheral surface of the image carrier 1, along the image carrier rotation direction A, a charger 4, an exposure optical system 5, yellow (Y), magenta (M),
The developing devices 6Y, 6M, 6C and 6B for accommodating the cyan (C) and black (B) color developers, the intermediate transfer member unit 7, the image carrier cleaning device 8 and the neutralizer 9 are provided. The charger 4 includes a charging wire 10 made of a tungsten wire or the like, a shield plate 11 made of a metal plate, and a grid plate 12. By applying a high voltage to the charging line 10, the charging line 10 causes corona discharge, and the image carrier 1 is uniformly charged via the grid plate 12. Reference numeral 13 is an exposure light beam of image data emitted from the exposure optical system 5. In an example of a laser printer, the exposure light beam 13 is controlled by a signal from a host computer or the like, and a plurality of electrostatic latent images corresponding to specific components among a plurality of predetermined color components on the image carrier 1 are controlled. Form an image. The developing devices 6Y, 6M, 6C and 6B for the respective colors are removably stacked in a storage portion provided in the machine body. The intermediate transfer member unit 7 includes three intermediate transfer member conveying rollers 15, 16 and 17 supporting a belt-shaped intermediate transfer member 14 made of a conductive resin or the like, and the image carrier 1 to the intermediate transfer member 14. It has an intermediate transfer roller 18 which is arranged so as to face the image carrier 1 with the intermediate transfer member 14 interposed therebetween for transferring the above development. Here, the surface perimeter of the intermediate transfer member 14 is nominally equal to the surface perimeter of the image carrier 1. Reference numeral 19 denotes an intermediate transfer member cleaning device for scraping off the residual toner on the intermediate transfer member 14, which is separated from the intermediate transfer member 14 while a composite image is formed on the intermediate transfer member 14, and is used for cleaning. It abuts the intermediate transfer member 14 only when it is used. Reference numeral 20 is a paper cassette that stores paper 21. Paper 21
Are fed one by one from the paper cassette 20 to the paper transport path 23 by the paper feed roller 22. Reference numeral 24 is a registration roller for aligning the positions of the composite image formed on the sheet 21 and the intermediate transfer member 14, and is in pressure contact with the driven roller 25. Reference numeral 26 denotes a paper transfer roller for transferring the composite image formed on the intermediate transfer member 14 onto the paper 21, and rotates in contact with the intermediate transfer member 14 only when the composite image is transferred onto the paper 21. Reference numeral 27 denotes a fixing device including a heat roller 28 having a heat source inside and a pressure roller 29,
The composite image transferred onto the paper 21 is pressed by the heat roller 28 and the pressure roller 29 by the pressure and heat as the paper is rotated.
And fix it to form a color image. Reference numerals 30a and 30b denote a first paper discharge roller pair provided on the downstream side of the fixing device 27. Reference numeral 31 is a switching member for switching the conveyance path of the paper 21 to either the first paper ejection tray 32 or the second paper ejection tray 36, and the switching member 31 has a switching arm portion 31a. The switching member 31 and the switching arm portion 31a are rotatably supported by a shaft 31b.
It rotates integrally around the switching member shaft 31b. 32
Is a first paper ejection tray provided on the side of the machine body, and is rotatably supported by a hinge 32a.
Are in contact with and separated from the switching arm portion 31a. 33 is paper 2
1 is an inversion guide that guides 1 upward. Reference numerals 34a and 34b denote a second pair of paper discharge rollers provided in the machine upper discharge port 35. Reference numeral 36 is a second paper discharge tray provided on the upper part of the machine body.

The operation of the conventional electrophotographic apparatus configured as described above will be described below.

In FIG. 2, first, a high voltage is applied to a charging wire 10 in a charger 4 connected to a high-voltage power source to cause corona discharge, and the surface of the image carrier 1 is uniformly -700V to -800V.
It is charged to about V. Next, the image carrier 1 is rotated in the direction of the arrow A, and an exposure beam such as a laser beam corresponding to a predetermined black (B) of a plurality of color components is formed on the surface of the image carrier 1 which is uniformly charged. When 13 is irradiated, the electric charge disappears in the irradiated portion on the image carrier 1 and an electrostatic latent image is formed. On the other hand, the developing device 6B in which the black developer contributing to the development is stored is brought into contact with the image carrier 1 by the separating / connecting means (not shown) according to the information from the host computer or the like. The other developing devices 6Y, 6M and 6C are separated from the image carrier 1. When a potential difference is applied between the developing device 6B and the image carrier 1 while bringing the developer into contact with the image carrier 1 at this contact position, the developer is applied to the electrostatic latent image portion formed on the image carrier 1. The toner adheres to form a visible image and the development is completed. The developing device 6B which has completed the development is moved from the contact position with the image carrier 1 to the separation position by the separating / contacting means.

Next, for example, when the color of cyan (C) is selected, the developing device 6C comes into contact with the image carrier 1 to start the development of cyan. In the case of a printer using four colors, the developing operation is sequentially repeated four times to form four color black (B), cyan (C), magenta (M), and yellow (Y) toner images on the intermediate transfer member 14. Form a superimposed composite image. The composite image thus formed is applied to the paper transfer roller 26 with a high pressure and is transferred to the paper 21 sent from the paper cassette 20 along the paper transport path 23 by the pressure, and then transferred to the fixing device 27. The toner is sent and fixed there by heat and the sandwiching pressure of the heat roller 28 and the pressure roller 29 to form a color image. The paper 21 that has passed through the fixing device 27 reaches the first paper discharge roller pair 30a and 30b.

In the state shown in FIG. 2, the switching member 31 opens the conveying path on the side of the reversing guide 33 on the downstream side of the first paper discharge roller pair 30a, 30b, and is integrated with the switching member 31. Switch arm 31a provided
Is an operating protrusion 32b at the bottom of the first paper ejection tray 32.
And the conveyance path on the side of the first paper discharge tray 32 is closed. Therefore, the first paper discharge roller pair 30
The paper 21 having the image surface facing up to a and 30b is sent to the reversing guide 33 with the image surface facing right in FIG. 2, and the image surface faces downward by the second pair of discharge rollers 34a and 34b. In this state, the sheet is discharged to the second sheet discharge tray 36. That is, in the state shown in FIG. 2, the sheet 21 is ejected with its image surface facing downward, and the face-down state is output.

On the other hand, in the state shown in FIG. 3, the user rotates the first paper output tray 32 around the hinge 32a from the state shown in FIG. 2 so that the first paper output tray 32 is provided below the first paper output tray 32. The operating projection 32b is also rotating. As a result, the switching arm portion 31a that comes into contact with the actuating projection 32b and the switching member 31 that is integral with the switching arm portion 31a are connected to the switching member shaft 3.
It rotates in the counterclockwise direction in FIG. 3 around 1b, and the switching member 31 closes the entrance of the reversing guide 33. In this state, the paper 21 is ejected by the first paper ejection roller pair 30a, 30b.
When the paper is fed, the paper 21 is fed to the first paper ejection tray 32 with the image surface facing upward, as shown by the chain line arrow in FIG.
Be delivered to. That is, in the state shown in FIG. 3, the face-up state is output.

[0010]

The speed of the first print is important as the function of the electrophotographic apparatus. However, in the above configuration, when the number of prints is 1 or less, if the switching member 31 is in the face-down state, the length of the conveyance path inside the machine until the paper 21 is discharged is in the face-up state. Since it is longer than that, the speed of the first print will decrease. Further, in order to increase the speed of the first print, the user needs to intentionally switch the switching member to the face-up state, which is very troublesome.

[0011]

In order to solve the above-mentioned problems, the present invention solves the above problems by first ejecting a sheet in a face-up state in which the image surface faces upward and in a face-down state in which the image surface faces downward. When the number of prints is 1 or less, a second discharge tray that is discharged in 1), a switching member that selectively switches the paper conveyance path to either the first discharge tray or the second discharge tray, A drive unit that operates the switching member so that the paper is discharged to the first discharge tray.

[0012]

According to the present invention, with the above-described structure, even if the user does not perform the switching operation one by one, when the number of prints is 1 or less, the first print is performed in the face-up state in which the sheet conveyance path is short, and the fast print speed Can be improved.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An electrophotographic apparatus according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a side view of an electrophotographic apparatus in a face-up output state according to an embodiment of the present invention.

Here, the same components as those in the above-mentioned conventional electrophotographic apparatus are designated by the same reference numerals and detailed description thereof will be omitted.

Reference numeral 37 is a drive unit such as a solenoid connected to the switching member 31 for rotating the switching member 31 about the switching member shaft 31b to switch between the face-up and face-down states.

The operation of the electrophotographic apparatus of the present invention constructed as above will be described below.

In FIG. 1, first, a high voltage is applied to a charging wire 10 in a charger 4 connected to a high-voltage power source to cause corona discharge, and the surface of the image carrier 1 is uniformly -700V to -800V.
It is charged to about V. Next, the image carrier 1 is rotated in the direction of the arrow A, and an exposure beam such as a laser beam corresponding to a predetermined black (B) of a plurality of color components is formed on the surface of the image carrier 1 which is uniformly charged. When 13 is irradiated, the electric charge disappears in the irradiated portion on the image carrier 1 and an electrostatic latent image is formed. On the other hand, the developing device 6B in which the black developer contributing to the development is stored is brought into contact with the image carrier 1 by the separating / connecting means (not shown) according to the information from the host computer or the like. The other developing devices 6Y, 6M and 6C are separated from the image carrier 1. When a potential difference is applied between the developing device 6B and the image carrier 1 while bringing the developer into contact with the image carrier 1 at this contact position, the developer is applied to the electrostatic latent image portion formed on the image carrier 1. The toner adheres to form a visible image and the development is completed. The developing device 6B which has completed the development is moved from the contact position with the image carrier 1 to the separation position by the separating / contacting means.

Next, for example, when the color of cyan (C) is selected, the developing device 6C comes into contact with the image carrier 1 to start the development of cyan. In the case of a printer using four colors, the developing operation is sequentially repeated four times to form four color black (B), cyan (C), magenta (M), and yellow (Y) toner images on the intermediate transfer member 14. Form a superimposed composite image. The composite image thus formed is applied to the paper transfer roller 26 with a high pressure and is transferred to the paper 21 sent from the paper cassette 20 along the paper transport path 23 by the pressure, and then transferred to the fixing device 27. The toner is sent and fixed there by heat and the sandwiching pressure of the heat roller 28 and the pressure roller 29 to form a color image. The sheet that has passed through the fixing device 27 reaches the first sheet discharge roller pair 30a, 30b.

In FIG. 1, when the number of printed sheets according to the print information sent from the host computer is 1 or less, the driving unit 37 automatically operates before the leading edge of the conveyed paper 21 reaches the switching member 31. The switching member 31 that is driven mechanically and is connected to the drive unit 37 is rotated counterclockwise about the switching member shaft 31b to switch to a face-up state in which the conveyance path is short. When the paper 21 is conveyed in this state, the paper 21 that has passed through the fixing device 27 and subsequently passes through the first paper discharge roller pair 30a, 30b is not guided upward by the switching member 31 and is first discharged in the shortest time. The sheet is discharged onto the paper tray 32 in a face-up state with the image surface facing upward.

[0020]

As described above, according to the present invention, the first discharge tray for discharging the paper in the face-up state with the image surface facing upward and the first discharge tray for discharging the paper in the face-down state with the image surface facing downward. The second discharge tray, a switching member that selectively switches the paper transport path to either the first discharge tray or the second discharge tray, and the switching member that switches the paper when the number of prints is one or less. Has a driving unit that operates so as to be discharged to the first discharge tray, so that the user does not have to operate each
When the number of prints is 1 or less, a short conveyance path is selected, and the speed of first print can be improved.

[Brief description of drawings]

FIG. 1 is a side view of an electrophotographic apparatus in a face-up output state according to an embodiment of the present invention.

FIG. 2 is a side view of a conventional electrophotographic apparatus in a face-down state.

FIG. 3 is a side view of a conventional electrophotographic apparatus in a face-up output state.

[Explanation of symbols]

 21 paper 31 switching member 32 first paper discharge tray 36 second paper discharge tray 37 drive unit

Claims (1)

[Claims] 1. An electrophotographic apparatus for performing printing on an image side of a sheet by an electrophotographic method, wherein a sheet is discharged in a face-up state in which the image side faces upward, and an image side faces downward. And a switching member that selectively switches the paper transport path to either the first discharge tray or the second discharge tray, and the number of prints. And a drive unit that operates the switching member so that the sheet is discharged to the first discharge tray when the number of sheets is one or less.