JPH04269767A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain excellent image quality while keeping the precision of an image forming position such as printing and copying positions to a sheet. CONSTITUTION:Two side plates 32a and 32b facing each other are fixed and erected on the bottom plate 31 of a device main body, and a sliding/guiding members 35, 39, 41, and 43 for attaching each unit of an image forming device and positioning members 36, 38, 40, 42, and 44 are provided on only the side plates. The positioning reference of each unit is only a single side plate, so that the accurate positioning of each unit can be attained and the excellent image quality can be obtained.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, such as a copying machine, a printer, or a facsimile machine, in which a paper feeding unit, an image forming unit, a conveying unit, a fixing unit, etc. are removably attached to the main body of the apparatus.

0002

2. Description of the Related Art Image forming apparatuses such as copying machines, printers, facsimile machines, etc., in which a paper feeding unit, an image forming unit, a conveying unit, a fixing unit, etc. are removably attached are well known in the art. This will be explained with reference to FIG.

In FIG. 6, a paper feed unit 2 is removable from the front side of the bottom plate 1 of the apparatus main body, a developing unit 3 is removable from the side plate 4 from the right side, and an optical writing unit 5 is removable from the upper unit 6 from above. Each unit is guided and positioned by a different member.

0004

[Problems to be Solved by the Invention] As mentioned above, the positioning of each unit is affected by the accumulation of component dimensions of each member, making it impossible to maintain the accuracy of the copying or printing position on the paper, and the tip Image quality is affected by misalignment of the registration or horizontal registration margin position, or occurrence of skew.

An object of the present invention is to eliminate the above-mentioned inconveniences in an image forming apparatus, to facilitate the attachment and detachment of each unit, and to maintain the accuracy of copying or printing positions on paper to obtain good image quality.

[0006]

[Means for Solving the Problems] According to the present invention, the above-mentioned problems are solved by forming the sliding guide members and positioning members of each removable unit on the same side plate fixed to the main body of the apparatus.

[0007] Furthermore, in order to solve the above problems, the present invention proposes that the side plate is a molded product.

Furthermore, in order to solve the above-mentioned problems, the present invention proposes that each unit is biased against the positioning member after being installed.

[0009]

[Function] Each unit of the image forming apparatus is slidably guided and positioned only by the side plates fixed and erected on the bottom plate of the apparatus, so the reference for positioning each unit is a single common side plate, and therefore each unit Accurate positioning is now possible.

0010

Embodiments Hereinafter, embodiments of the present invention will be explained using a laser printer shown in FIGS. 1 to 5. In Figure 1,
A first paper feed cassette 11 and a second paper feed cassette 12 are arranged below the printer 10. First paper cassette 11
The transfer paper P loaded on the paper is sent out by a paper feed roller 13, and after passing through an intermediate conveyance path 14, a pair of registration rollers 15, 15
It reaches the transfer section 16 through the. Reference numeral 17 denotes an image forming unit including a photoreceptor belt, a developing toner magazine 18 is arranged on the right side of this image forming unit, and an optical writing unit 19 is arranged below it. The transfer paper P onto which the toner image has been transferred in the transfer section 16 is then transferred to the fixing unit 2.
The sheet is pressed and fixed by the pair of fixing rollers 21 and 21 of No. 0, and is discharged to the first paper discharge tray 23 via the pair of paper discharge rollers 22 and 22.

When the switching claw 24 is in the illustrated position, the transfer paper P is not discharged to the first paper discharge tray 23, but is discharged to the second paper discharge tray 26 via the conveyance path 25. When the switching claw 27 is in the position shown in the figure, the transfer paper is transferred to the conveyance path 25.
Then, it reaches a pair of reversing rollers 28, 28 for double-sided printing, and by reversing the pair of reversing rollers, it passes through a pair of feed rollers 29, 29 and reaches a pair of registration rollers 15, 15 again. 30 is a paper feed tray for printing postcards.

In FIG. 2, side plates 32a and 32b are vertically fixed on both sides of a main body bottom plate 31. The side plates 32a and 32b are precisely positioned with respect to the main body bottom plate 31, and are reinforced by attaching stays 33 and 34 between the side plates.

FIG. 2 shows the direction in which each unit is attached to the side plates 32a and 32b. That is, the paper feed cassette 11 is viewed from the front side, and the developing toner magazine 18 is viewed from the front side above the image forming unit 1.
7 from the upper side of the front side to the lower side, the fixing unit 20 from the upper side to the lower side, and the optical writing unit 19 from the opposite side of the front side, respectively. Then, the positioning member is attached.

A guide member 35 for the paper feed cassette 11 is protruded from the lower inner surface of the side plate 32b shown in FIG. 3, and a positioning hole 36 for the paper feed cassette is provided below this guide member. Furthermore, a guide groove 11a corresponding to the guide member 35 is provided on the side surface of the paper feed cassette 11. When the guide groove 11a is inserted into the guide member 35 and the paper feed cassette 11 is inserted into the main body of the apparatus, a wheel (not shown) attached to the lower side of the paper feed cassette is fitted into the positioning hole 36 when it is fully inserted. This positions the paper feed cassette.

Further, on the inner surface of the side plate 32b, there are a guide member 37 and a positioning hole 38 for the developing toner magazine 18, and the magazine is provided with a guide protrusion 18a and a stopper (not shown) corresponding to these.

For the image forming unit 17, a guide member 39 and a positioning hole 40 are provided in the side plate 32b. Correspondingly, the arrangement of the guide section and the positioning section in the image forming unit 17 is the same as described above.

A guide member 41 and a positioning protrusion 42 are provided on the inner surface of the side plate 32b of the fixing unit 20, as shown in FIGS. 3 and 4. Corresponding guide members and positioning recesses are arranged in the fixing unit 20 in response to these guide members and positioning protrusions.

For the optical writing unit 19, the side plate 32b
As shown in FIGS. 3 and 5, there is a guide protrusion 4 on the inner surface of the
3 and a positioning hole 44 are provided. On the other hand, the optical writing unit 19 is provided with a corresponding guide groove 19a and a positioning protrusion.

After each unit is installed, it is biased by an elastic member (not shown) such as a spring, or fastened with a screw or the like. Furthermore, the positioning of each unit in the thrust direction perpendicular to the paper plane of FIG. 3 is performed by urging each unit using an elastic member provided on one of the side plates.

In addition to the units described above, it is also possible to configure the intermediate conveyance path 14 shown in FIG. 1 as a unit, and provide guide members and positioning members therefor on the inner surfaces of the side plates 32a and 32b.

[0021]

Effects of the Invention Since each unit of the image forming apparatus is accurately positioned, the accuracy of image formation in printing on paper, copying, etc. is improved, and good image quality can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a laser printer to which the present invention is applicable.

FIG. 2 is a perspective view showing the mounting direction of each unit on both side plates provided on the bottom plate of the main body according to the present invention.

FIG. 3 is a plan view showing the inner surface of the side plate provided with guide members and positioning members for each unit.

FIG. 4 is a perspective view showing a fixing unit guide member and a positioning protrusion.

FIG. 5 is a perspective view showing a guide protrusion and a positioning hole for an optical writing unit.

FIG. 6 is an exploded perspective view of a conventional printer in which each unit is detachable.

[Explanation of symbols]

10 Laser printer 11
Paper cassette 11a
Guide groove 14 Intermediate conveyance path 17
Image forming unit 18
Developing toner magazine 18a
Guide protrusion 19 Optical writing unit 19a Guide groove 20 Fixing unit 32a, 3
2b Side plate 35, 37, 39, 41 Guide member

Claims (4)

[Claims] 1. An image forming apparatus in which a paper feeding unit, an image forming unit, a transport unit, a fixing unit, etc. are removably attached to the apparatus main body, wherein a sliding guide member and a positioning member of each of the removable units are attached to the apparatus main body. An image forming apparatus characterized in that the image forming apparatus is formed on the same fixed side plate. 2. The image forming apparatus according to claim 1, wherein the side plate is a molded product. 3. The image forming apparatus according to claim 1, wherein each unit is biased against a positioning member after being attached. 4. The image forming apparatus according to claim 1, wherein each unit is fixed with a screw after being attached.