JPH03128853A - Image formation apparatus - Google Patents

Abstract

PURPOSE:To absorb impact of a transfer material which enters a fixing portion to prevent the impact from being transmitted to a transfer portion by providing a transport belt moved along the upper surface of a suction deck formed to be turned down at the corners and a suction means for sucking a transfer material to the transport belt through suction holes of the suction deck. CONSTITUTION:A transfer material S which has passed through a transfer portion X is sucked towards a transport belt 33 by a suction device 40, and transported to a fixing portion Y by the friction with the transport belt 33. At this time, as a suction deck 20 for supporting the transport belt 33 is formed to be turned down at the corners, the transfer material S is bent like a mountain in the vicinity of the top portion 22 of the suction deck by its firmness to form a gap with the transport belt 33 and produce a slack in such a manner as to surround the gap. Accordingly, when the leading end of the transfer material S enters the fixing portion Y and the impact at that time is transmitted towards the trailing end side of the transfer material S, the impact is absorbed as defor mation of the slack portion not to be transmitted to the transfer portion.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to image forming apparatuses such as copying machines, printers, and facsimiles.

[Conventional technology]

In image forming apparatuses that use powder toner, the toner transferred to the transfer material in the transfer section is heated and fixed to the transfer material in the fixing section, or in small image forming apparatuses, the toner is transferred from the transfer section to the fixing section. Because the distance is short, the leading edge of the transfer material during transfer may enter the fixing section, and the impact at that time is transmitted to the transfer material located in the transfer section, which may disturb the transferred toner image and cause poor image quality. .

For this reason, two so-called air suction type conveyor devices are installed between the transfer section and the fixing section, and by changing their conveyance speeds, slack is formed in the transfer material between the two conveyor devices, and this slack is removed. An image forming apparatus designed to absorb the impact upon entering the fixing section has been proposed in Japanese Utility Model Application Laid-Open No. 63-138554.

[Problem to be solved by the invention]

However, the image forming apparatus requires a special mechanism or control device for switching the transfer material conveyance speed of the conveyor device, which has the problem of complicating and increasing the size of the apparatus.

[Means to solve the problem]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and in an image forming apparatus, a conveying device for conveying a transfer material from a transfer section to a fixing section is provided with a suction deck formed in an angular shape. The apparatus includes a conveyance heald that moves along the upper surface of the suction deck, and a suction means that sucks the transfer material onto the conveyance belt through suction holes provided in the suction deck.

[Effect]

According to the configuration, the transfer material that has passed through the transfer section is sucked toward the conveyor belt by the suction device, and is conveyed to the fixing section by friction with the conveyor belt.

At this time, since the suction deck that supports the conveyor belt is formed in a curved shape, the transfer material bends in a mountain shape near the top of the suction deck due to its own stiffness, and the gap between the conveyor belt and the transfer material is bent. A gap is formed between the two, and slack is created surrounding this gap.

Therefore, when the leading edge of the transfer material enters the fixing section and the impact at that time is transmitted toward the rear body of the transfer material: 11, this impact is absorbed as deformation of the slack portion and transmitted to the transfer section. There isn't.

〔Example〕

The present invention will be explained in detail below.

In the image forming apparatus shown in FIG. 1, the outer peripheral surface of a photoreceptor 1 rotating in the direction of arrow a is charged by a charger 2, and the charged area is exposed to image light 3 to form an electrostatic latent image. This electrostatic latent image is visualized as a toner image by the developing device 4, and the toner image is transferred onto a transfer material at a portion (hereinafter referred to as "transfer portion") X facing the transfer charger 5.

The transfer material is fed one sheet at a time from the paper feed section 6, and is transferred to the transfer section
sent to.

The transfer material that has passed through the transfer section is discharged.

Next, the conveyance device 9, which is the gist of the present invention, will be explained.

The conveying device 9 is generally composed of a suction deck 20, a conveyor device 30, and a suction device 40.

As shown in FIG. 3, the suction deck 20 has an upper guide surface 21 formed in a U-shape with a predetermined angle α, and a top portion 22 of the suction deck 20 is shifted from the center toward the fixing section. The slope 23 on the side is longer than the slope 24 on the fixing section side. In addition, suction holes 25° and 26 are provided on the sides of the slopes 23 and 24, respectively, and the suction holes 2 on the transfer section side
The opening area of No. 5 is larger than the opening area of the transfer section side suction hole 26.

The conveyor device 30 consists of a pair of rollers 3L32 and a conveyor belt 33 having a plurality of holes (not shown).The rollers 31 and 32 are arranged on the transfer section side and the fixing section side of the suction deck 20, rollers 31,3
2 and the conveyor belt 3 so as to surround the suction device 20.
3 and is supported along the upper guide surface 21 of the suction deck 20 between rollers.

The suction device 40 is arranged under the suction deck 20,
The air on the belt is sucked through the suction holes 25 and 26 of the suction deck 20 and through the holes of the conveyance heald 33.

In the above configuration, the transfer material S that has passed through the transfer section
．． It is attracted by the suction air sucked downward from 26 and is attracted to the conveyor belt 33 .

The transfer material S attracted to the conveyor belt 33 is transferred to the roller 31,
With the movement of the conveyor belt 33 that moves around the suction deck 20 based on the rotation of 32, the sheet is conveyed in the direction of arrow m, moves upward along the slope 23 on the transfer section side of the suction deck 20, passes through the top portion 22, It goes down along the fixing side slope 24.

Also, on the way down along the slope 24, the suction device 4
0, it is attracted by the suction air sucked downward from the suction hole 26 and is attracted to the conveyor belt 33. However, the suction hole 26 on the fixing section side has a smaller opening area than the suction hole 25 on the transfer section side, and the suction force F of the suction hole 26 on the fixing section side is
is smaller than the suction force F1 of the sloped hole 25 on the transfer section side.

As described above, the transfer material S is conveyed along the upper guide surface 21 of the suction deck 20, and moves in a curved state near the top 22 of the suction deck.

That is, in the vicinity of the top portion 22, the transfer material S moves in a lifted state from the conveyor belt 33, and a slack Sa is formed in the transfer material itself.

In the fixing device 10, an upper fixing roller 51 and a lower fixing roller 5
2 are rotating in the directions of arrows A and C, respectively, and the leading edge of the transfer material S that has passed through the conveyance device 9 is guided to the contact area (fixing section) Y of rollers 51 and 52. At this time, the leading edge of the transfer material S hits the outer peripheral surface of either the upper or lower roller, and the impact causes the transfer material S being transported in the transport device 9 to move backward relative to the belt 33 moving on the fixing section side slope 24. However, the amount of retraction is absorbed by the deformation of the slack Sa. In addition, part of the impact is also transmitted to the transfer material S moving on the transfer section side slope 23. Here, the suction force F of the suction device 40 against the transfer material S is increased, so the transfer material S However, it does not move backward relative to the conveyor belt 33.

Therefore, the toner image transferred to the transfer material S at the transfer portion X is not disturbed, and a high-quality image is obtained.

Incidentally, the bending angle α of the top portion 22 of the suction deck varies depending on the stiffness of the transfer material S used in the image forming apparatus, and is approximately 150,170 in the case of plain paper commonly used in copying machines, printers, facsimile machines, etc. ' is appropriate, and a range of 160 to 165 degrees is most preferable for forming slack Sa.

In the above explanation, the suction forces F, F2 on the transfer material S on both sides are changed by changing the sizes of the suction holes 25 on the transfer section side and the suction holes 26 on the fixing section side. Two devices 40 are provided, and the air volume of the suction device connected to the suction hole 25 on the transfer section side is made larger than the air volume of the suction device connected to the suction hole 26 on the fixing section side, thereby creating a difference in suction force. You may also do so.

〔Effect of the invention〕

As is clear from the above description, the image forming apparatus according to the present invention does not require any mechanism or control to switch the drive during image formation, and has a simple configuration that reduces the impact of the transfer material entering the fixing section. It is possible to prevent it from being absorbed and transmitted to the transfer section.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of the image forming apparatus, FIG. 2 is a sectional view of the conveying device, and FIG. 3 is a perspective view of the suction deck. 9... Conveyance device, 20... Suction deck, 21
...Top guide surface, 22..Top part, 25. 26...
・Suction hole, 30...Conhair device, 31.32...
Roller, 33...conveyor belt, 40...suction device, X
...Transfer section, Y...Fixing section, S...Transfer material, Fl,
F2... Suction power.

Claims (1)

[Claims] (1) In an image forming apparatus that transports a transfer material onto which a toner image has been transferred in a transfer section to a fixing section, and here fixes the toner image to the transfer material, transport that transports the transfer material from the transfer section to the fixing section. equipment,
A suction deck formed in a V-shape, a conveyor belt that moves along the upper surface of the suction deck, and a suction device that sucks the transfer material toward the conveyor belt through suction holes provided in the suction deck. An image forming apparatus comprising: