JPH02120868A - image forming device - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention includes a transfer means for transferring an image on an image carrier onto a transfer material, and a fixing means for fixing the transferred image on the transfer material. The present invention relates to an image forming apparatus.

[Background Art] As the image forming apparatus of the present invention, various printers such as a copying machine 1 using electrophotographic technology, a printer using a laser beam, a liquid crystal shutter, or an LED can be used. As an example of these, a laser beam printer (hereinafter referred to as LBP) using a laser beam will be explained.

FIG. 6 shows a schematic diagram of the configuration of an example of a conventional LBP.

Reference numeral 100 denotes an exterior casing of the printer, in which an image forming means mechanism is incorporated. The exterior casing has a structure that can be divided into a lower half 100A and an upper half 100B.
With respect to A, the upper half-rest 100B is the rear end side hinge shaft 101
It can be opened as shown by the two-dot chain line or closed as shown by the solid line.

To briefly explain the configuration of this example, a transfer material S such as paper is stored in a cassette 109, and the cassette 109 is attached to the main body. The transfer material S is transferred to 1 by the pickup roller llO.
The sheets are separated and fed one by one and conveyed by a pair of conveyor rollers 111a and 1llb.
and registration rollers 11 by guides 112 and 113.
Sent up to 4. The transfer material S is sent by a registration roller 114 to an image carrier 103 that forms an image in synchronization with the image signal, the image on the image carrier 103 is transferred by a transfer charger 116, and then transferred to a conveyor belt 117.
is sent to the fixing device 118 by Here, the transfer material S is sandwiched between a pair of fixing rollers 119, the image is fixed thereon, and the image is fixed at the discharge port 100.
Ejected from 0.

On the other hand, images are mainly generated by a process cartridge 102 that houses a laser scanner 107 that scans a laser light source (not shown) disposed in the upper half 100B in the axial direction of the image carrier 103, and a process cartridge 102 that houses various process devices that perform a well-known electrophotographic process. Formation takes place. Here L is laser scanner 1
A laser beam 108 scanned by the laser beam 07 is a mirror that guides the laser beam to the image carrier 103.

The main components inside the process cartridge 102 include an image carrier 103, a charger 104, a developer 105,
This is a cleaning device 106.

However, the conventional LBP, which is configured to transport the transfer material after transfer in a substantially lateral direction and guide it to the fixing section as shown in FIG. 6, has the following problems.

l) In order to remove the jammed transfer material S, it was necessary to open the large upper half 110B containing the image carrier, and the operability was not very good.

2) The size of the main body becomes large, and a large space is required to install one main body. In particular, the space above and below the fixing device becomes wasted.

There were other problems.

[Object of the Invention] The present invention has been made in view of the above problems, and an object of the present invention is to provide a small and inexpensive image forming apparatus.

[Structure of the Invention] In order to achieve the above object, the present invention includes a movable image carrier, a transfer means for transferring an image on the image carrier to a transfer material, and a transfer means for transferring an image on the image carrier to a transfer material. In an image forming apparatus having a fixing unit that fixes an image, the position of the fixing unit of the fixing unit is set from vertically above the transfer unit with respect to the position of the transfer unit that transfers the image from the image carrier to the transfer material. It is also characterized in that it is arranged tilted toward the fJj carrier side.

[Embodiment] An embodiment of the image forming apparatus of the present invention will be described below with reference to the drawings.

FIG. 1 shows a cross-sectional view of the LBP. The main body L of the apparatus is divided into a fixed side IA and an opening/closing side IB that divides and opens/closes the transport path of the transfer material S. The opening/closing side IB supports the transfer material S so as to be freely openable and closable around a hinge shaft 2. are stored in a cassette 3, and when the paper feed roller 4 rotates, they are pressed by the paper feed roller 4 and separated one by one by a butt 5 made of a high friction material.

The transfer material S separated one by one is sent to a pair of registration rollers 7 by a pair of guide plates 6, synchronized with the image formed on one image carrier 8, and sent along a transfer guide 25 to a transfer section. Here, the transfer section constitutes a contact section by an image carrier 8 and a transfer roller 9 that is in pressure contact with the image carrier 8, and the image is transferred to the transfer material S at this transfer section, and the transfer material S is sent to the fixing device 10. The fixing device IO includes a heater roller 11 that has a built-in heater and heats it, and a pressure roller 1 that presses the transfer material S against the heater roller 11.
There are 2 pairs of rollers, and the transfer material S is transferred to the heater roller 11.
A substantially arc-shaped guide 13 and an outer device 4 provided on the side opposite to the unfixed image on the transfer material to guide the image to the contact area between the pressure roller 12 and the pressure roller 12. It is composed of separation claws 15 and the like.

The image transferred onto the transfer material S is fixed in the fixing section, which is the contact portion between the heater roller 11 and the pressure roller 12, and the transfer material S is discharged from the paper discharge port 1c and placed on the tray 16 by 1!1 m. . Furthermore, there is a flapper 17 between the fixing section and the paper discharge port 1c, and by switching this, the conveying direction of the transfer material S can be changed, and the transfer material S can be moved to the paper discharge port Ic.
Paper can also be ejected from D. At this time, the transfer material S is oriented in the opposite direction from when it was discharged from the discharge port tC, with the image surface facing upward.

On the other hand, regarding the image forming section, the image forming section scans a laser beam in the axial direction of a process cartridge 18 and an image carrier 8, which are detachably attached to a main body in which well-known image forming process equipment is housed in a single container. In this embodiment, which is roughly divided into a scanner 19, an OPC (organic photoconductor) drum is used as the image carrier.

The inside of the process cartridge 18 will be described briefly.

A uniform negative charge is applied to the image carrier 8 by the charging roller 20, and a latent image is formed by laser light emitted from the scanner 19 according to the image information and exposing the image area. The toner t in the developing container 21 is sent to the developing section 23 by the stirring plate 22 and is thinly coated on the developing sleeve 24 . This toner t is negatively charged and reversely developed on the image carrier 8 according to the latent image formed on the image carrier 8, and is transferred to the transfer material S at the transfer section described above. In the above embodiments, reversal development is employed, but it goes without saying that one-pass development may also be used.

The image transfer section will now be described in more detail with reference to FIGS. 2 to 4. 2 is a partially enlarged view of the registration roller pair 7 to the fixing section 10 of the present invention, FIG. 3 is a partially enlarged view of the transfer section, and FIG. 4 is a partially enlarged sectional view of FIG. 3 viewed from below. .

The transfer section is composed of the image carrier 8 and the transfer roller 9 as described above. Here, the transfer material S before and after the transfer section
We will describe the behavior of After passing through the pair of registration rollers 7, the leading edge of the transfer material S is conveyed along the transfer guide 25 and first comes into contact with the image carrier 8, and is placed on the image carrier side of the contact area N between the image carrier 8 and the transfer roller 9. (Fig. 3). Here, in order to prevent the leading edge of the transfer material S from breaking and failing to enter the transfer section, the transfer material S is guided so as to come into contact with the hard image carrier 8 first, and its leading edge is uniformly guided to the transfer section. .

As shown in FIG. 3, the transfer roller 9 is composed of a conductive metal shaft 9-8 and a semi-conductive rubber sponge 9-2.
is pressed by a spring, etc. Further, the transfer roller 9 is supplied with a positive current having a polarity opposite to the electric charge of the toner image on the image carrier 8 from its metal shaft 9-1, so that the electrostatic charge on the low-density photographic material S during transfer by pressure contact is applied to the transfer roller 9. Stable transfer can be performed.

Furthermore, when a transfer roller is used, compared to when a transfer corona discharger is used, there is less loss of charge applied to the transfer material, and the electrostatic adhesion between the transfer material S and the image carrier is weakened, so the transfer material S can also be stably separated.

Since the transfer material S after the minute Ill is released from the restraint of the image carrier 8 and the transfer roller 9 at the other end A of the contact area N of the transfer roller 9, the conveyance direction B of the transfer material S is approximately at the point A. 8, and the transfer material S is stably carried out in this direction.

In this way, the transfer material S can be restrained by the transfer roller 9 at the transfer section, so that it can be carried out stably. As shown in FIG. It can be carried out by tilting toward the carrier 8 side. Also 1
In this embodiment, there is no need for a member to convey the transfer material between the transfer section and the fixing section.

In this example, when A4 size paper weighing 70g/■2 is used, and the fixing section of the fixing device is located above the transfer section, about 70 seconds, the angle θ formed by the conveying direction B and the vertical direction should be set to 12 @ or less. I was able to set it. Therefore, the fixing device is approximately 15 wus
Since it can be placed inside the main body, the space below the fixing device is not wasted, which allows the main body to be made smaller and costs to be reduced. Here, if the above-mentioned θ is made larger than 12''', the transfer material will bend downward under its own weight, resulting in unstable conveyance, or the unfixed image on the transfer material will come into contact with the equipment on the image carrier 8 side, causing the image to become unfixed. Note that this θ varies depending on the distance between the transfer section and the fixing section, the stiffness of the paper, the size of the paper, etc.

In addition, when the conveyance direction is set vertically, it is necessary to convey the public transfer material S whose conveyance direction from the transfer section is unstable along with the guide 13, and due to frictional electrification with this guide 13, the undefined state on the transfer material S However, according to this embodiment, the conveyance direction of the transfer material S from the transfer section is adjusted to the guide 13.
Since it is tilted to the opposite side, contact with the guide 13 can be minimized, and therefore, disturbances in the unfixed image due to frictional charging between the transfer material S and the guide 13 can be eliminated.
You can obtain stable, high-quality images.

Furthermore, as shown in FIG. 1, in this embodiment, the transfer material S is conveyed in a substantially vertical direction to shorten the length of the conveyance path, and mechanical parts such as drives are mounted on the left side of the apparatus, and electrical and optical parts are mounted. is placed on the right side of With this configuration, the reliability of transporting the transfer material S can be improved, and maintenance can also be facilitated.

Furthermore, in this embodiment, the fixing device 10 can be placed above the process cartridge 18, so that the main body can be made smaller and costs can be reduced.

FIG. 4 shows a sectional view of FIG. 3 when viewed from below.

The transfer roller 9 has its shaft 9-. Hold a gear 9° at one end of the
Gear 9-3 is gear 8-1 fixed to the end of image carrier 8.
Normally, the hardness of the rubber contact 9-2 of the transfer roller 9 and the pressing force of the transfer roller are regulated. The distance between the transfer roller 9 and the image carrier 8 is kept constant, or a spacer 9-4 made of a slidable resin or the like is provided on the transfer roller 9, and this is used to control the rotation of the image carrier 8 as shown in the figure. Central axis 8-2. Alternatively, if the transfer roller 9 and the image carrier 8 are brought into contact with the surface 8-3 at the end of the non-image area of the image carrier 8, a constant distance can be maintained between the transfer roller 9 and the image carrier 8, and the contact area N of the transfer roller 9 can be maintained. The amount or contact force can be regulated more stably.

Another embodiment will be described with reference to FIG. FIG. 5 is a cross-sectional view of the transfer section in the axial direction. Unlike the transfer roller of the above embodiment, a conventional transfer corona charger 116 is used as the transfer means, and both sides of the non-image area of the transfer material S are charged with the transfer corona. A rotating roller 26 that slides on the outer periphery of the container 116 to press the transfer material S against the image carrier 103 and is driven is provided. By sandwiching the transfer material S between the rotating roller 26 and the image carrier 103, the transfer corona charger 116 can also achieve almost the same effect as the transfer roller. In this example, by fitting the rotating roller 26 and the transfer corona charger 116, the position of the transfer corona charger 116 can be determined accurately. Further, by providing an elastic layer around the outer periphery of the rotating roller 26, transmission of vibrations to the image carrier 103 can be reduced, and the image carrier 103 does not need to be damaged even when the opening/closing section is opened or closed due to a jam or the like.

[Effects of the Invention] As described above, according to the present invention, the position of the fixing section is inclined toward the image carrier side from the vertically above the transfer section with respect to the position of the transfer section. The space below the means is not wasted, and a compact and inexpensive image forming apparatus can be obtained.

[Brief explanation of drawings]

FIG. 1 is a main sectional view of a laser beam printer showing an embodiment of the present invention; FIGS. 2, 3, and 4 are enlarged sectional views of a transfer section showing an embodiment of the present invention; FIG. FIG. 3 is a sectional view of a transfer section showing another embodiment of the present invention. FIG. 6 is a main sectional view of a conventional LBP. 1--Device main body 2...Hinge shaft 3...Cassette 4...Paper feed roller 5...Pad 6...Guide plate pair 7...Registration roller pair 8...Image carrier 9...Transfer roller 10--Fuser 11--Heater roller 12--Pressure roller 13--Guide 14--Outer device 5--Separation claw 16--Tray 17-- - Flapper 18... Process cartridge 19... Scanner 20... Charging roller 21 -... Developing container 22... Stirring plate 23 -... Developing section 24... Developing sleeve 25... Transfer guide 26...Rotating roller

Claims (5)

[Claims] (1) In an image forming apparatus including a movable image carrier, a transfer means for transferring an image on the image carrier to a transfer material, and a fixing means for fixing the image transferred onto the transfer material, An image characterized in that the position of the fixing section of the fixing means is inclined toward the image carrier side rather than vertically above the transfer section with respect to the position of the transfer section that transfers the image from the image carrier to the transfer material. Forming device. (2) The image forming apparatus according to claim (1), wherein the transfer means is provided in contact with the image carrier. (3) The image forming apparatus according to claim (2), wherein the transfer means includes a transfer rotating body. (4) The image forming apparatus according to claim (1), wherein the fixing means includes a pair of rotating bodies. (5) The image forming apparatus according to claim (3), wherein the transfer means rotates via a power transmission means provided at an end of the image carrier.