JP2000172090A - Transfer device of printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To excellently transfer a developed image to various recording material by varying the interval in the recording material conveyance direction of a recording material guide means provided on the upstream and downstream sides of a transfer means in the recording material conveyance direction. SOLUTION: Blades 18 and 29 which guide form conveyance are provided on the upstream and downstream sides of a transfer unit 10 in the form conveyance direction and fitted to support frames 30 and 31, which are fitted to a transfer frame 32 so that they can move. The interval L between the tips of the blades 28 and 29 is varied according to a form ream weight and the thickness of a form. A form different from a form which is used so far is stored in a form hopper, information based upon the change is sent to a controller, a shaft 35 is rotated with a signal based upon the change, and an eccentric cam 36 is changed in the position where it comes into contact with the blades 28 and 29; and the blades 28 and 29 are moved to set transfer width L suitable to the form to be used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a transfer device of a printing device for transferring a developed image formed on an image carrier to a recording material.

[0002]

2. Description of the Related Art As a prior art of the present invention, for example,
No. 0-107862 is known. 60-
According to Japanese Patent No. 107862, a photosensitive drum rotatably supported as an image carrier is shown, and a transfer device provided opposite to the surface of the photosensitive drum and a recording material are provided between the photosensitive drum and the transfer device. A tractor that conveys (printing paper) and conveys printing paper that has passed between the photosensitive drum and the transfer device to a subsequent stage; a lower separator and an upper separator provided on the upstream and downstream sides in the paper conveyance direction with respect to the transfer device; And a mechanism for moving the lower separator and the upper separator toward and away from the surface of the photosensitive drum, wherein the paper conveyed by the tractor is brought into contact with the surface of the photosensitive drum by the lower separator and the upper separator. FIG. 1 shows a laser beam printer in which a toner image formed on a photosensitive drum by a transfer device is transferred to paper. There.

In this type of printing apparatus, the recording material used is not limited to one type, and various types such as thin paper and thick paper are selected and used. In the case of thin paper, it is easy to transport along the transport path because the rigidity of the paper is weak, but in the case of thick paper, if the paper is forcibly transported along the transport path because of the rigidity of the paper, the paper will be loaded with a load There is a risk that the speed will fluctuate. Therefore, in the above conventional configuration, it is considered that the position of the lower separator and the upper separator is centered on the recording material having high rigidity, and the lower separator and the upper separator are located at a position where the conveyance of the recording material having high rigidity does not occur. The distance between the leading end of the lower separator and the leading end of the upper separator in the paper transport direction is fixed and fixed.

[0004]

However, the diversification of recording materials used has further advanced, and the amount of continuous paper is 64 g / m ^2.
１５157 g / m ² and the range is wide. Also, the thickness of the paper is in the range of about 80 μm to 180 μm.

At the time of transfer, the paper is brought into close contact with the surface of the photosensitive drum by an electrostatic attraction force and a pressing force by the lower separator and the upper separator. At this time, the force for contacting the photosensitive drum side acts on the thick paper due to the strong rigidity of the paper itself, but the force for contacting the photosensitive drum side hardly occurs for thin paper, and the contact with the photosensitive drum does not occur. It was not performed well and a problem occurred in transferability.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a transfer device of a printing apparatus capable of performing good transfer of a developed image to various recording materials.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an image carrier which is supported so as to be movable endlessly, a transfer means provided opposite to the surface of the image carrier, and a transfer means provided between the image carrier and the transfer means. First conveying means for conveying the recording material toward the recording medium, second conveying means for conveying the recording material having passed between the image carrier and the transfer means to a subsequent stage, and upstream and downstream of the transfer means in the recording material conveyance direction. And a recording material guiding means supported on the image carrier so as to be able to approach / separate from the surface of the image carrier.
The recording material conveyed by the first and second conveying means is brought into contact with the surface of the image carrier by the recording material guide means, and the developed image formed on the image carrier is transferred to the recording material by the transfer means. In a transfer device of a printing apparatus, recording is performed by a recording material guide unit provided on the upstream side in the recording material conveyance direction with respect to the transfer unit, and a recording material guide unit provided on the downstream side in the recording material conveyance direction with respect to the transfer unit. This is achieved by providing a means for varying the interval in the material transport direction.

[0008]

An embodiment of the present invention will be described below in detail with reference to the drawings.

First, the overall configuration of a printing apparatus to which the present invention is applied will be described with reference to FIG. In FIG.
Reference numeral 1 denotes a laser beam printer serving as a printing device, and the photosensitive drum 21 starts rotating in the direction of an arrow based on a printing operation start signal from a controller 22 thereof. Photosensitive drum 2
1 rotates at a speed corresponding to the printing speed of the laser beam printer 1 and continues to rotate until the printing operation is completed. When the photosensitive drum 21 starts rotating, a high voltage is applied to the corona charger 2, and the surface of the photosensitive drum 21 is uniformly charged with, for example, a positive charge.

The rotary polygon mirror 3 is a laser beam printer 1
As soon as the power is turned on, the motor starts rotating, and the constant-speed rotation is maintained with high accuracy while the power is turned on. A laser beam output from a light source 4 composed of a semiconductor laser, a light emitting diode, or the like is reflected by the rotating polygon mirror 3 and irradiated while scanning the photosensitive drum 21 through the fθ lens 5.

When the character data or graphic data converted into the dot image is sent from the controller 22 to the laser beam printer 1 as an on / off signal of the laser beam, the portion where the laser beam is irradiated on the surface of the photosensitive drum 21 and the irradiation are performed. And a so-called electrostatic latent image is formed. When the photosensitive drum area holding the electrostatic latent image reaches a position facing the developing device 6, toner is supplied to the electrostatic latent image, and a portion on the photosensitive drum 21 where the charge on the photosensitive drum 21 has disappeared due to the irradiation of the laser beam. For example, the toner charged to a positive charge is attracted by static electricity,
A toner image is formed thereon.

The continuous paper 7 stored in the paper hopper 11 is rotated by the paper transport tractor 8 in synchronization with the timing at which the toner image of the print data formed on the photosensitive drum 21 reaches the transfer position. And transfer device 1
It is transported between 0.

The toner image formed on the photosensitive drum 21 is sucked onto the sheet 7 by the action of the transfer unit 10 which applies a charge of the opposite polarity to the toner image on the back side of the sheet 7.

In this manner, the sheet 7 set in the sheet hopper 11 is transferred to the sheet transport tractor 8 and the transfer unit 1.
0, the sheet is conveyed to the fixing device 12 via the sheet conveying tractor 9 and the buffer plate 24. The sheet 7 arriving at the fixing device 12 is preheated by a preheater 13 and then heated and pressed by a nip formed by a pair of fixing rollers including a heating roller 14 having a heater lamp 25 and a pressure roller 15. The toner image is nipped and conveyed, and the toner image is fused and fixed on the sheet 7.

The paper 7 sent out by the heating roller 14 and the pressure roller 15 is sent out to the stacker table 19 side by the paper sending out roller 16 and
The swinging fins 17 are alternately folded along the perforations by the swinging operation of the swing fins 17, and the folding state is adjusted by the rotating paddle 18.
Stacked on top of 9. The area that has passed the transfer position of the photosensitive drum 21 is cleaned by the cleaning device 20, and is prepared for the next printing operation.

In FIG. 1, reference numeral 23 denotes a display screen for displaying information based on the state of the laser beam printer 1 during a printing operation. Further, the above-described buffer plate 24 is provided with the paper transport tractor 9 and the fixing rollers 14 and 1.
This is to absorb the slack or tension generated in the sheet 7 when the sheet conveyance speed difference occurs between the sheets 5.
Reference numeral 26 denotes a web member provided so as to be in contact with the surface of the heating roller 14 and to be able to be wound, and is used for cleaning the surface of the heating roller 14 and applying a release agent to the surface of the heating roller 14. Things.

Next, a detailed configuration of the transfer device according to the present invention will be described with reference to FIG.

The transfer unit 10 is detachably supported on a guide rail 27 provided on a fixing member such as a frame of a laser beam printer. A blade 28 for guiding the sheet conveyance is provided on the upstream side of the transfer unit 10 in the sheet conveyance direction, and a blade 29 for guiding the sheet conveyance on the downstream side of the transfer unit 10 in the sheet conveyance direction. The blades 28, 29 are mounted on support frames 30, 31. The support frames 30 and 31 are attached to the transfer frame 32. Here, the support frames 30, 31 are located at positions indicated by solid lines in FIG.
It is attached to the transfer frame 32 so as to be movable between the positions indicated by broken lines.

The transfer frame 32 is connected to an output shaft of a motor 34 via a connecting member 33. When the motor 34 is driven, the blade 28 is connected via the connecting member 33, the transfer frame 32 and the support frames 30, 31. , 29 approach or separate from the surface of the photosensitive drum 21.

According to the present invention, the tip of the blade 28 and the blade 2
9 is characterized in that the distance L from the leading edge (hereinafter referred to as “transfer width”) is varied based on the continuous paper amount and the thickness of the paper. Hereinafter, a configuration for changing the transfer width L will be described.

When the sheet stored in the sheet hopper 11 shown in FIG. 3 is changed to a sheet different from the sheet used so far, the information based on the change is transmitted to the controller 22 and the change based on the change is performed. For example, the shaft 35 shown in FIG. 1 is rotated by a signal, the contact position of the eccentric cam 36 provided on the shaft 35 with the blades 28 and 29 is changed, and the blades 28 and 29 are moved to be suitable for the paper to be used. The transfer width L is set.

Next, the relationship between the thickness of the paper used and the transfer width L will be described in detail with reference to FIG. Blade 2 of FIG.
Regarding positions 8, 29, the solid line position indicates the use of thick paper, and the dashed line position indicates the use of thin paper. In this embodiment, the transfer width L
Is L '<L "when L' is thick paper and L" is thin paper. That is, in the case of thin paper, the transfer width L is set large, and the winding angle θ with respect to the surface of the photosensitive drum 21 (the winding angle θ is a line connecting the rotation center (not shown) of the photosensitive drum 21 and the tip of the blade 28) Is defined by the angle between the rotation center of the photosensitive drum 21 and the line connecting the tip of the blade 29), and the electrostatic attraction between the sheet 7 and the photosensitive drum 21 during transfer is increased as compared with thick paper. Let it.
In particular, in the case of a configuration in which the paper 7 is transported by a tractor, the paper 7
There is a tendency that speed fluctuation due to backlash or catch between the feed hole and the tractor pin occurs. However, since the transfer width L increases, the paper easily follows the surface of the photosensitive drum 21, so that the transfer between the photosensitive drum and the paper at the time of transfer is performed. The relative speed difference can be reduced, and consequently the transfer deviation can be reduced.

[0023]

As described above, according to the present invention, the recording material guide means provided upstream of the transfer means in the recording material transport direction, and the recording material guide means provided downstream of the transfer means in the recording material transport direction. The present invention provides a transfer device of a printing apparatus capable of performing good transfer of a developed image to various types of recording materials, since the device includes means for varying a distance between the recording material guide unit and the recording material conveyance direction. it can.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a transfer device of the present invention.

FIG. 2 is an explanatory diagram illustrating a relationship between a sheet thickness and a transfer width.

FIG. 3 is an overall configuration diagram of a printing apparatus to which the present invention is applied.

[Explanation of symbols]

7 ... paper, 10 ... transfer unit, 21 ... photosensitive drum, 27 ... guide rail, 28,29 ... blade, 30,31 ... support frame, 32 ... transfer frame, 33 ... connection member, 3
4 ... motor, 35 ... shaft, 36 ... eccentric cam.

Continuation of front page (72) Inventor Yukio Omeme 1060 Takeda, Hitachinaka-shi, Ibaraki F-term in Hitachi Koki Co., Ltd. (Reference) 2H032 AA02 BA05 BA12 BA19 BA23 BA25 3F101 FB04 FB05 FE02 FE11 FE17 LA07 LB03

Claims (3)

[Claims] An image carrier supported endlessly; transfer means provided opposite to the surface of the image carrier; and a transfer member for conveying a recording material between the image support and the transfer means. 1 transport means, a second transport means for transporting the recording material having passed between the image carrier and the transfer means to a subsequent stage, and provided upstream and downstream of the transfer means in the recording material transport direction,
Recording material guide means supported so as to be able to approach / separate from the surface of the image carrier, wherein the recording material conveyed by the first and second conveyance means is brought into contact with the surface of the image carrier by the recording material guide means. And a transfer device of a printing device for transferring the developed image formed on the image carrier to the recording material by the transfer device, wherein a recording material guide unit provided on the upstream side in the recording material conveyance direction with respect to the transfer unit. And a means for varying the distance in the recording material conveyance direction from a recording material guide means provided downstream of the transfer means in the recording material conveyance direction. 2. The transfer device according to claim 1, wherein the interval is changed based on a continuous amount of a recording material to be used. 3. The transfer device according to claim 1, wherein the distance increases as the thickness of the recording material decreases.