JPH03128852A - 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 positioning a conveyer apparatus on the up-stream side in the transport direction of a transfer material above a downstream side conveyer apparatus in a connection portion both conveyer apparatus. CONSTITUTION:A difference in level is firmed between two adjacent conveyer apparatus 20 and 30, and a transfer material S sent from a transfer portion is separated from the conveyer in the above difference-in-level portion to form a slack. Accordingly, when the leading end of the transfer material enters a fixing portion and the impact at that time is transmitted towards the trailing end of the transfer material S', the impace is absorbed as deformation of the slack portion. The sucking force of a suction device 31 on the fixing portion Y side for the transfer material S is set smaller than that of an upstream side suction device 21, so that when the transfer material S enters the fixing portion Y, the transfer material S can form a large slack naturally and without strain.

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, but 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 that is still being transferred 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 purpose, 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 Japanese Utility Model Application Publication No. 63-138554 proposes an image forming apparatus designed to absorb the impact when the image forming apparatus enters the fixing section.

[Problem to be solved by the invention]

However, the image forming apparatus requires a special mechanism and control equipment to switch the transfer material conveyance speed of the conveyor device, making the apparatus complicated and large.

In addition, in order to create slack in the transfer material with a speed difference, the only way is to weaken the suction force of the conveyor device on the transfer material or to increase the speed difference. However, if the suction force is weakened, the impact from the fixing section is likely to be transmitted to the transfer section, and there is a risk that the entire transfer material may be lifted and the unfixed image may be disturbed. On the other hand, if the speed difference is increased, stress is likely to be applied to the transfer material, which may also disturb the unfixed image.

[Means to solve the problem]

Therefore, the present invention has been made to solve the above-mentioned problems, and a plurality of conveyor devices equipped with suction devices are arranged in the area from the transfer section to the fixing section, and at least two adjacent conveyor devices are connected to each other. At the connection between the two, the conveyor device on the upstream side in the conveyance direction of the transfer material is positioned above the conveyor device on the downstream side, and the suction force of the conveyor device on the transfer section side toward the transfer material is made larger than that on the fixing side. be.

[Function] According to the above structure, a step is formed between the two adjacent competitor devices, and the transfer material sent from the transfer section separates from the conveyor at the step and forms a slack. Therefore, when the leading edge of the transfer material enters the fixing section and the impact at that time is transmitted toward the rear end of the transfer material, this impact is absorbed as deformation of the slack portion. In addition, the suction force on the transfer material of the suction device on the fixing section side is weaker than that of the suction device on the upstream side, so when the transfer material enters the fixing section, the transfer material naturally and naturally bends a lot. be able to. Further, since the suction force of the suction device on the transfer section side against the transfer material is greater than that of the suction device on the downstream side, even if deformation occurs in the slack portion, the deformation force will not be transmitted to the transfer section. Therefore, the toner image transferred to the transfer material at the transfer section is not disturbed.

〔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 It is discharged onto the tray 12.

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

The conveying device essentially consists of a first conveyor device 20 and a second conveyor device 30, each of which is associated with a suction device 21.31.

In the conveyor device 20.30, two rollers 22 and 23
．． (a plurality of bells having a predetermined width surrounding 32 and 33)
24 and 34 are respectively wound, and are configured to rotate in the directions of arrows A and C by a drive device (not shown). Also, the bell located at the top between the rollers) 24.3
Suction decks 25.35 are provided along the lower surface of each of the belts 4, and air on the belt is sucked downward by a suction device 21.31 through suction holes 26.36 provided in these suction decks 25.35. It looks like this.

The conveyor device 20.30 connects the downstream roller 23 of the first conveyor device 20 located upstream with respect to the transport direction of the transfer material S (direction of arrow m) to the second conveyor located downstream. It is located above the upstream roller 32 of the device 30, and a step is provided at the connection portion thereof. Furthermore, by making the air volume of the suction device 21 larger than the air volume of the suction device 31, the suction force F acting on the transfer material S conveyed by the belt 24 acts on the transfer material S conveyed by the heald 34. It should be larger than the suction force F2. It should be noted that providing a difference in suction force can also be achieved by varying the opening area of the suction holes 26 and 36.

In the conveying device 9 having the above configuration, the transfer material S sent from the transfer section is pulled by the belt 24, and the belt 2
4 and moves in the direction of the arrow along with the belt 24.

Next, the transfer material that has reached the downstream side of the first conveyor device 20 goes down the step and is conveyed onto the heald 34 of the second conveyor device 30 . Then, at a portion facing the suction hole 36 , the sheet is attracted by the satanylon air of the suction device 31 , comes into close contact with the heald 34 , and moves to the fixing device 10 together with the belt 34 . Further, a slack A is formed in the transfer material S passing through the stepped portion.

In the fixing device 10, an upper fixing roller 10a and a lower fixing roller 10b rotate in the directions of arrows d and e, respectively.
The leading edge of the transfer material S that has passed through the second conveyor device 30 is guided to the contact area (fixing section) Y of the rollers 10a and 10b. At this time, when the leading edge of the transfer material S hits the outer peripheral surface of either the upper or lower roller, the impact causes the transfer material S being conveyed on the second conveyor device 30 to retreat relative to the belt 34, causing the step to The transfer material S curves as shown in FIG. 3, and the amount of retreat of the transfer material S is absorbed there. Here, since the suction force F2 of the suction device 31 on the fixing side is weaker than the suction force F of the suction device 21 on the transfer side, the transfer material S naturally forms a large slack at the stepped portion. It has good absorption of impact force. The impact is also transmitted to the portion of the transfer material S that is being conveyed to the first conveyor device 20, but here, the suction force F of the suction device 20 against the transfer material S is large, and a small force Since the transfer material S is not moved backward relative to the belt 24, the impact is not further transmitted to the transfer section side. Therefore, the toner image transferred to the transfer material S at the transfer section X is not disturbed, and a high-quality image can be obtained.

In addition, in the above explanation, there are two
Although a case has been described in which one conveyor device 20, 30 is installed, the present invention can also be applied to an image forming apparatus provided with even more conveyor devices.

〔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 structure that absorbs the impact of the transfer material entering the fixing section. can be prevented from being transmitted to the transfer section.

In addition, the suction force on the transfer material of the conveyor device on the fixing side is weaker than that on the transfer side, so the transfer material naturally creates a large slack at the step between the conveyor devices and enters the fixing section. It is possible to sufficiently absorb the impact when the transfer is performed and prevent this impact force from being transmitted to the transfer section.

On the other hand, the suction force on the transfer material of the conveyor device on the transfer section side is made stronger than that on the fixing section side, and the transfer material is strongly held there, so that the impact is not transmitted to the transfer section.

Therefore, a high-quality image can be obtained without transfer deviation at the transfer section or disturbance of unfixed images.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of the image forming apparatus, and FIGS. 2 and 3 are sectional views of the conveying device. 9...Conveyor device, 20.30...Conveyor device, 2]
, 3]...Suction device, X...Transfer section, Y...Fixing section, S...Transfer material, F,,F2 Suction force.

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, a suction device is provided in an area from the transfer section to the fixing section. At least two adjacent conveyor devices are arranged such that the upstream conveyor device in the transfer direction of the transfer material is located above the downstream conveyor device at the connection point between the two, and the transfer section side An image forming apparatus characterized in that the suction force of the conveyor device against the transfer material is greater than that of the fixing side.