KR20080052002A - Image forming apparatus - Google Patents

Abstract

An imaging apparatus is provided to shorten a time for performing double-faced printing by a simple structure and improve printing efficiency. A paper feeding part and a developing part engage with the first driving motor(M1) by a plurality of middle gears and receive power. A fusing part(30), a paper discharging part, and an inverting part engage with the second driving motor(M2) by a plurality of middle gears and receive power. The fusing part includes a fusing roller(31). The fusing roller is connected with the second driving motor by the first one-way gear(60).

Description

Image forming apparatus

1 is a view schematically showing an image forming apparatus according to the present invention.

2 is a diagram schematically illustrating an internal driving structure of the image forming apparatus according to the present invention.

3 is a perspective view showing a one-way gear of the image forming apparatus according to the present invention.

* Description of symbols on the main parts of the drawings *

1..Main body 3..Register roller

10. Feeder 13. Pick-up roller

20. Development 22. Photosensitive drum

30. Fixing unit 31. Fixing roller (heating roller)

40..Medium 41,42.Medium roller

50..Inversion 51,52..Duplex roller

60. 1st Way Gear 61 .. Fixed Roller

62..Non-fixing roller 63..Hub clutch

66 .. 2nd Way Gear 67 .. Main Gear

68..Booth Gear

M1 .. 1st drive motor M2 .. 2nd drive motor

P..Paper

The present invention relates to an image forming apparatus, and more particularly, to an image forming apparatus capable of double-sided printing.

BACKGROUND OF THE INVENTION An image forming apparatus such as a laser printer or a copying machine using an electrophotographic method generally includes a one-side printing apparatus for forming desired image information on only one surface of a printing paper and a double-side printing apparatus for forming desired image information on both sides of the printing paper. In particular, in the case of the duplex printing apparatus, the duplex printing is made possible by guiding the sheet reversing unit to reenter the image forming unit (developing unit).

In addition, the conventional image forming apparatus includes two driving motors, and the first motor drives the image forming unit, the paper feeding unit, and the inverting unit, and the second motor drives the fixing unit and the discharge unit.

Therefore, since the speed at the time of conveying the paper for the back printing becomes the same as the paper conveying speed at the time of the one side printing as described above, there was a problem that the duplex printing efficiency is much lowered.

In order to overcome this disadvantage, there was a method of increasing the paper feed speed during the back printing relatively, but in this case, when the paper front end reaches the image forming unit or the feeding roller (register roller), which is the one-side printing path, it is connected by multiple gears. Due to the time delay between the image forming unit and the inverting unit, a difference occurs between the feed rate when printing on one side and the feeding speed when printing on both sides. Therefore, in order to prevent this, an idle gear, a clutch, etc. are additionally required, which increases the manufacturing cost.

The present invention is to solve the above problems of the prior art, an object of the present invention is to provide an image forming apparatus that can improve the printing efficiency by reducing the time required for double-sided printing with a simple structure.

The image forming apparatus according to the present invention for achieving the above object is provided with a feed unit, a developing unit, a fixing unit, a discharge unit and an inverting unit for double-sided printing, the image forming apparatus is provided with a first and second drive motors for driving each unit In the, the feeder and the developing part are engaged with the first drive motor by a plurality of intermediate gears to receive power, and the fixing unit, the discharge unit and the inverting part are engaged with the second drive motor by a plurality of intermediate gears to receive power.

In addition, the fixing unit of the image forming apparatus according to the present invention includes a fixing roller, and the fixing roller is connected to the second driving motor and the first one-way gear.

In addition, the first one-way gear of the image forming apparatus according to the present invention comprises a main fixed gear that meshes with the second driving motor and a non-fixed gear that engages with the fixing roller, and the inverting portion includes a duplex roller. It is connected to the two-drive motor and the second one-way gear, the main gear of the second one-way gear meshes with the main fixed gear of the first one-way gear, and the auxiliary gear meshes with the duplex roller.

In addition, the inverting portion of the image forming apparatus according to the present invention includes a duplex roller, the duplex roller is connected to the second drive motor and one-way gear.

In addition, the rotational speed of the second driving motor for driving the duplex roller of the inverting portion when printing both sides of the image forming apparatus according to the present invention is faster than the rotational speed during single-sided printing.

In addition, the rotation speed of the duplex roller of the image forming apparatus according to the present invention is varied by the rotation speed of the second driving motor.

Hereinafter, an image forming apparatus according to the present invention will be described in detail with reference to the accompanying drawings. Here, the present embodiment is illustrated as an example of a multi-function printer capable of double-sided printing, but the present invention is not limited thereto, and may be applied to an image forming apparatus such as an inkjet printer or a copying machine through appropriate modification and modification.

1 schematically shows an image forming apparatus according to the present invention. Referring to the drawings, the image forming apparatus of the present invention includes a paper feeding unit 10 for supplying paper P, a developing unit 20 for developing an image on paper, and an image developed by applying heat and pressure to the paper. And a fixing unit 30 for fixing to the paper, a discharge unit 40 for discharging the finished paper to the outside, and an inverting unit 50 for double-sided printing.

The paper feeding unit 10 includes a paper tray 11 on which paper P is loaded, and a spring 12 elastically supporting the paper tray 11. The paper loaded in the paper tray 11 is picked up one by one by the pickup roller 13 and moved to the developing part 20 side through the feed roller 14.

The developing unit 20 includes a photosensitive drum 22 having an electrostatic latent image formed on the surface by the laser scanning 21, a charging roller 23 for charging the photosensitive drum 22, and a photosensitive drum 22. A developing roller 24 for developing the formed electrostatic latent image into a visible image, and a transfer roller 25 for pressing the sheet toward the photosensitive drum 22 so that the visible image of the photosensitive drum 22 is transferred to the sheet.

The fixing unit 30 fixes the visible image transferred to the paper by applying heat and pressure. The fixing unit 30 is provided to face the heating roller 31 and the heating roller 31 for applying heat to the paper to which the toner is transferred. It consists of a pressure roller 32 to maintain a constant fixing pressure between the heating roller 31.

The discharge unit 40 includes a plurality of discharge rollers 41 and 42 installed so that the paper passing through the fixing unit 30 can be transferred to the stacking unit 2 provided on the upper portion of the image forming apparatus main body 1. .

The reversing unit 50 is rotated by the discharge rollers 41 and 42 before the paper printed on one side for exiting the exiting unit 40 is printed along the paper conveying path separately provided in the main body 1. The reentry into the developing unit 20 and the fixing unit 30 includes a plurality of duplex rollers 51 and 52 positioned on the paper conveying path.

2 schematically shows an internal drive structure of the image forming apparatus according to the present invention. Referring to the drawings, the image forming apparatus of the present invention is operated by the first driving motor (M1) and the second driving motor (M2), the paper feeding portion 10 and the developing portion 20 through a plurality of intermediate gears The first driving motor (M1) is meshed with, the fixing unit 30, the discharge unit 40 and the inverting unit 50 is engaged with the second drive motor (M2) through a plurality of intermediate gears to receive power.

According to the present invention, the fixing roller 31 of the fixing unit 30 (illustrated as a heating roller 31 in the drawing, but the pressure roller 32 is also possible) is the first driving motor M1 and the first one-way gear ( Connected via 60). Since the one-way gear is a technique for the main pipe, the first one-way gear 60 is the main fixed gear 61 and the non-fixed gear 62, the main fixed gear 61 and the subsidiary gear. A hub clutch 63 disposed between the fixing gear 62, and protrusions 64 and 65 inclined to correspond to each other on the inner surface of the fixing gear 62 and one end of the corresponding hub clutch 63; Is formed. Therefore, when the main fixing gear 61 rotates in one direction, the projections 64 and 65 mesh with each other and transmit power to the unfixed gear 62, and when the rotation is performed in the other direction, the projections 65 are different projections. While passing (64), the power is not transmitted to the fixed gear (62).

That is, since the fixing roller 31 meshes with the main fixed gear 61 of the first one-way gear 60 via the second driving motor M2 and the intermediate gear, when the forward rotation in the one-side printing direction is performed, Power of the second driving motor M2 is transmitted, but power is not transmitted when the second driving motor M2 reversely rotates for duplex printing. This facilitates the removal of the paper when the paper is jammed in the fixing unit 30, and does not drive the fixing unit 30 when the second driving motor M2 is reversely rotated for duplex printing. This is to extend the life of the product.

In addition, the duplex roller 51 of the inversion unit 50 is connected to the second driving motor M2 and the second one-way gear 66 via the intermediate gear.

That is, the duplex roller 51 is connected to the second driving motor (M2) and the second one-way gear 66, preferably the main gear 67 constituting the second one-way gear 66 is the first The main fixing roller 61 of the one-way gear 60 is engaged, and the sub-gear 68 is engaged with the duplex roller 51.

Therefore, the duplex roller 51 is always rotated in a direction opposite to the rotational direction of the delivery roller 41 when the second driving motor M2 is operated so that the rotation of the delivery roller 41 forward in one printing direction does not rotate. When the discharge roller 41 is reversely rotated for double-sided printing, it is rotated toward the developing unit 20 side (register roller 3). At this time, the fixing roller 31 does not rotate as described above.

On the other hand, the rotational speed of the second drive motor (M2) for driving the duplex roller 51 for double-sided printing is faster in the opposite direction than the rotational speed that was driving the fixing unit 30 and the delivery unit 40 during one-side printing It is preferable. This is because the overall duplex printing speed can be increased by increasing the rotation speed of the duplex roller 51. In order to increase the rotational speed of the duplex roller 51, the rotational speed of the second driving motor M2 may be increased. In this case, the duplex roller 51 and the discharge roller 41 may be faster than single-sided printing by adjusting the reduction ratio. It is preferable to rotate at the same speed.

Next, the printing operation of the image forming apparatus having the above configuration will be described in detail.

 When a signal about an image to be printed is input from the laser scanning 21 or an external computer for printing on one side, the first driving motor M1 operates to pick up the paper P loaded in the paper tray 11. 13), the leading edge of the paper passing through the register roller 3 of the main body 1 is aligned, and the developing portion 20 forms an electrostatic latent image on the paper. Subsequently, the second driving motor M2 operates to forward the paper having the electrostatic latent image passing through the fixing unit 30 to fix the image, and then discharge the paper to the stacking unit 2 through the discharge unit 40.

On the other hand, in duplex printing, the paper is conveyed through the discharge rollers 41 and 42 of the delivery unit 40 while the second driving motor M2 is reversely rotated before the paper printed on one side is discharged to the loading unit 3. The paper is conveyed to the path, and the duplex rollers 51 and 52 are rotated to reenter the paper into the register roller 3. At this time, the fixing roller 31 engaged with the second driving motor M2 and the first one-way gear 60 operates during the forward rotation of the second driving motor M2, but does not operate during the reverse rotation. The duplex roller 51 meshed with the second driving motor M2 and the second one-way gear 66 does not operate during forward rotation of the second driving motor M2 but operates during reverse rotation.

In addition, the rotational speed of the duplex roller 51 is increased by varying the rotational speed or gear ratio of the second driving motor (M2), so that the conveying speed of the paper printed on one side of the paper conveying path for printing on both sides is one side. Increased printing speed than printing speed improves overall printing speed.

As described in detail above, the image forming apparatus according to the present invention includes two driving motors, and separately operates the driving motor for driving the paper feeding unit and the developing unit and the driving motor for driving the fixing unit, the discharge unit, and the inverting unit, thereby printing one surface. The paper feed speed of paper and the paper feed speed of duplex printing can be easily adjusted.

In addition, the image forming apparatus according to the present invention facilitates control by connecting the rollers of the fixing unit and the reversing unit with one-way gears to the driving motor, respectively, in driving the fixing unit, the discharge unit, and the inverting unit by using one driving motor. Can be.

Claims (6)

An image forming apparatus comprising a paper feeder, a developing unit, a fixing unit, a discharge unit, and an inverting unit for double-sided printing, and provided with first and second driving motors for driving each unit. The paper feeding part and the developing part are engaged with the first driving motor by a plurality of intermediate gears to receive power. And the fixing unit, the discharge unit, and the inversion unit are engaged with the second driving motor by a plurality of intermediate gears to receive power. The method of claim 1, The fixing unit includes a fixing roller, And the fixing roller is connected to the second driving motor and the first one-way gear. The method of claim 2, The first one-way gear is composed of a main fixed gear that meshes with the second drive motor and an unfixed gear that engages with the fixing roller, The inversion unit is connected to the second drive motor and the second one-way gear, including a duplex roller, And the main gear of the second one-way gear meshes with the main fixed gear of the first one-way gear, and the sub-gear meshes with the duplex roller. The method of claim 1, The inversion unit includes a duplex roller, And the duplex roller is connected to the second driving motor and the one-way gear. The method according to claim 3 or 4, And a rotational speed of the second driving motor driving the duplex roller of the inversion unit in duplex printing is faster than a rotational speed in single-sided printing. The method of claim 5, And the rotation speed of the duplex roller is varied by the rotation speed of the second driving motor.

Images