JP2009151089A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact and light-weight printer which keeps excellent image quality by preventing an image forming section from being distorted even in a state where an original cover section is opened in an image forming apparatus having an original reading section. <P>SOLUTION: The image forming apparatus has a first frame including and holding the image forming section, and a second frame supporting the original reading section. The second frame is provided on the outside of a range where the first frame is projected from above, and is connected to the first frame so that it is displaced to the lower side of the apparatus. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a printer and a copying machine, and more particularly to an image forming apparatus provided with a document reading unit.

  2. Description of the Related Art Conventionally, an image forming apparatus capable of achieving high rigidity and light weight while preventing image distortion and the like in a facsimile machine, a copying machine, or a multifunction machine (MFP) having a function as a facsimile machine, a copying machine, and a printer. (See Patent Document 1).

According to this conventional apparatus, as shown in FIG. 10, the structure of the image forming unit is constituted by the mold frame 12, and the metal bottom plate forming the bottom surface of the image forming apparatus main body excluding the sheet feeding cassette unit. The mold frame 12 is supported by the (bottom plate member) 21. The original reading unit 9 is made up of the three columns 13, 14, 15 erected at the three corners of the bottom plate 21 and the box-shaped side plate (support side plate) 16 provided at the remaining one corner. I support it.
JP 2003-84517 A

  However, the conventional apparatus described above has the following problems.

  In recent multi-function machines, a model in which an automatic paper feed mechanism is provided in a document reading unit becomes standard as a result of an increase in the number of documents to be read, and the weight of the document reading unit tends to increase as the support sheet size of the document reading unit increases. It is in.

  In many cases, the multifunction peripherals are connected via a network, and the document reading unit and the image forming unit can be operated independently. That is, there may be a situation in which another user operates the image forming unit from the network while the user opens the automatic paper feeding mechanism of the document reading unit.

  When the automatic paper feeding mechanism is opened, the load on the side with the rotation center of the automatic paper feeding mechanism becomes large, and the image forming unit is distorted by the load of the automatic paper feeding mechanism and the document reading unit. When the image forming unit performs a printing operation in a state where the image forming unit is distorted, a problem that a good image cannot be obtained occurs.

  In the above-described conventional method, it is necessary to significantly strengthen the column supporting the document reading unit in order to prevent distortion of the image forming apparatus even when the weight of the document reading unit is increased and the automatic paper feeding mechanism is opened. . If the thickness of the column is increased in order to increase the strength of the column, there is a problem that the apparatus becomes larger and the apparatus weight also increases.

  In order to solve the above-described problems, the present invention provides an image forming apparatus having a document reading unit that reads a document and an image forming unit that forms an image on a recording material, and a first frame that includes and holds the image forming unit. A second frame that supports the document reading unit, and the second frame is provided outside a range in which the first frame is projected from above, and is below the apparatus with respect to the first frame. It is characterized by being connected to be displaceable.

  As described above, according to the present invention, it is possible to efficiently support the load of the document reading unit and prevent the occurrence of image distortion and the like.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a diagram showing an image forming apparatus according to an embodiment of the present invention. First, the document reading unit 100 and the image forming unit 101 will be described.

  As shown in FIG. 1, a document reading unit 100 is disposed above an image forming unit 101 that forms an image on a recording material. A document reading unit 100 that reads a document is a flat bed type document reading unit, and has a document reading surface on the upper surface and is a document pressing unit that can be freely opened and closed with respect to a base unit 103 in which document reading means 102 is stored. A pressing plate 104 is provided. The document pressing plate 104 is provided with an automatic document feeding mechanism 105 and a document stacking unit 106 which are automatic document supply units.

  FIG. 2 is a perspective view showing a state in which the document pressing plate 104 is opened, and the exterior of the image forming unit 101 is not shown for ease of explanation. As shown in FIG. 2, the document pressing plate 104 is connected to the base portion 103 by a document pressing plate rotation center 107a, 107b so as to be opened and closed. That is, the document pressing portion is supported so as to be rotatable with respect to the document reading portion.

  Then, the document pressing plate 104 is opened, the document is placed on the base portion 103, the document pressing plate 104 is closed, and then the document reading unit 102 is moved along a rail (not shown) to read the document.

  When reading an original using the automatic original feeding mechanism 105, the original is stacked on the original stacking unit 106 with the original pressing plate 104 closed. The original passes through the original reading means 102 on which the automatic original feeding mechanism 105 is stationary, and the original is read. When reading an original using the automatic document feeding mechanism, the original can be read continuously, so that a large amount of originals can be read efficiently. However, since the automatic document feeding mechanism 105 is installed on the document pressing plate 104, the total weight of the document reading unit 100 becomes heavy. This completes the description of the document reading unit 100.

  Next, the image forming unit 101 and the image forming process will be described.

  In FIG. 1, an image forming unit 101 includes a cassette 108 that stores sheets as recording materials. Further, this cassette 108 is detachably attached to the apparatus main body from the front in FIG. A pickup roller 109 is built in the right end portion of the cassette 108, and a sheet is conveyed from the cassette 108 in accordance with a print signal. A registration roller pair 110 is disposed on the downstream side. At this time, the registration roller pair 110 is stopped. Next, the sheet is conveyed to the image forming area by rotating the registration roller pair 110 in accordance with the timing of writing the image.

  The image forming area is formed by an intermediate transfer belt 111, a driving roller 112 for driving the intermediate transfer belt 111, and a driven roller 113. In the image forming area, the photosensitive drums 1a, 1b, 1c, and 1d, which are image carriers, and the primary transfer rollers 2a, 2b, 2c, and 2d, the laser scanner unit 114, the intermediate transfer belt cleaner 115, and the image are transferred to the sheet. For example, the secondary transfer roller 116 is used.

  Next, the image forming process will be described. After writing an electrical latent image on the photosensitive drum by the laser scanner unit 114, the latent image is developed by attaching toner to the latent image on each photosensitive drum by the developing roller. Then, four color images are sequentially placed on the intermediate transfer belt 111 by the primary transfer roller. The toner image created on the intermediate transfer belt 111 as described above is transferred onto the sheet by the nip between the secondary transfer roller 116 and the driving roller 112.

  Excess toner remaining on the intermediate transfer belt 111 is cleaned by the intermediate transfer belt cleaner 115 to prepare for the next image forming process. The above is the image forming process.

  Thereafter, the sheet is conveyed to a fixing unit, and heat and pressure are applied in a fixing unit (fixing device) 117 to fix the toner image on the sheet. The sheet is conveyed by a roller on the intermediate conveyance path 118, and is discharged onto the paper discharge tray 119 with the printing surface facing downward.

  As described above, since the sheet is transferred by each roller and sequentially fed to the downstream side, if the alignment between the rollers is shifted, the sheet is not conveyed straight, skewing occurs and print quality is impaired. Also, if the laser scanner unit 114 cannot write the laser to the exact position on the photosensitive drum due to the distortion of the frame, or if the photosensitive drum cannot transfer the toner to the exact position on the intermediate transfer belt, each color will shift. Will occur. The above is the description regarding the image forming unit 101.

Next, a frame configuration and a method of supporting each unit will be described with reference to FIG.
FIG. 3 is a perspective view in which the image forming apparatus is divided into parts. The image forming unit described in the description of the image forming unit 101, the pair of rollers for conveying the sheet, the fixing unit 117, the laser scanner unit 114, and the photosensitive drum are supported by the first frame 120. That is, the first frame contains and holds the image forming unit.

  The relative positions of the image forming unit, the sheet conveying roller, the fixing unit 117, the laser scanner unit 114, and the photosensitive drum are accurately determined by the front and rear side plates in the first frame 120.

  A unit that is not supported by the first frame 120, that is, a control board in which alignment does not affect image quality, and an electrical unit 121 such as a high-voltage power source and a low-voltage power source include a second frame 122 including leaf springs 123a, 123b, 123c, and 123d. Built in. That is, the second frame supports the document reading unit, and the rotation center of the document pressing unit is disposed on the second frame. In addition, the electrical unit 121 is fixed to the first frame with screws at a position indicated by a broken line in FIG.

  By incorporating the electrical unit 121 in the second frame 122 instead of in the first frame 120, the entire apparatus can be reduced in size.

  In this embodiment, the electrical unit 121 is fixed to the first frame 120 with screws. However, if the electrical unit 121 is disposed in the second frame, the second frame can be fixed to the first frame 120. Either may be fixed to 122.

  4 is an enlarged view before the plate spring 123b of the second frame is assembled. As shown in FIG. 4, the first frame 120 and the second frame 122 are screwed by the plate springs 123a, 123b, 123c, and 123d. Connect with.

  In addition to the leaf spring of the present embodiment, as shown in FIG. 5, the effect of the present invention can be obtained by utilizing the bending of the sheet metal 124, 125 itself of the second frame.

  In addition, as shown in FIG. 6, the second frame can be rotated with respect to the first frame by providing the first frame with a rotation center 128 of the second frame and connecting to the second frame. The effect of the present invention can be obtained even if it is disposed in the position.

  The document reading unit 100 is configured to be supported by the first frame 120 and the second frame 122, respectively. The document pressing plate rotation centers 107 a and 107 b of the document pressing plate 104 of the document reading unit 100 are arranged on the upper part of the second frame 122.

  Further, as shown in FIG. 7 which is a right side view of the main body and FIG. 8 which is a downward view of the main body, the first frame 120 includes first frame ground members 126a and 126b which are ground members for grounding to the ground. , 126c, 126d are disposed to support the first frame. The second frame grounding members 127a and 127b, which are grounding members for grounding to the ground, are also provided substantially below the document pressing plate rotation centers 107a and 107b. However, as shown in FIG. 7, when the document pressing plate 104 is closed, a gap of about 0.5 mm is provided between the ground and the second frame grounding member. The gap is 0.5 mm in this embodiment, but the second frame grounding member may be in contact with the ground in the closed state. In this embodiment, the second frame includes a grounding member having a gap when the document reading unit is not mounted on the surface on which the image forming apparatus is installed, and the grounding member is an image when the document reading unit is mounted. Grounding is performed on the same surface as the surface on which the forming apparatus is installed.

  By configuring the image forming apparatus as described above, as shown in FIG. 9, when the document pressing plate 104 is opened, the load applied to the rear side of the image forming unit 101 increases. However, since the second frame 122 is elastically deformed and the second frame grounding members 127a and 127b provided on the second frame 122 are grounded, the first frame 120 is not distorted. In FIG. 9, the second frame is drawn so as to be largely deformed, but in order to deepen the understanding, the elastic deformation is expressed larger than the actual one. Actually, the second frame grounding members 127a and 127b are grounded, and the gap between the second frame grounding member 127 and the ground of 0.5 mm or more is not deformed.

  As described above, the second frame is provided outside the range in which the first frame is projected from above, and is connected to the first frame so as to be elastically displaceable below the apparatus.

  Therefore, even when the image forming unit 101 performs the above-described image forming process with the document pressing plate 104 opened, the first frame 120 is not distorted due to the distortion due to the weight of the document reading unit 100. As a result, the alignment between the image forming unit and the sheet conveying roller and the fixing roller can be maintained normally, and skew feeding of the sheet can be prevented.

  Further, it is possible to prevent the image quality from being deteriorated due to a color shift that occurs because each color is not transferred to an accurate position on the intermediate transfer belt 111.

  In the present exemplary embodiment, the document reading unit is positioned above the image forming unit. However, the present invention can be applied to a paper discharge device, a personal computer, a display device, or the like.

1 is a diagram illustrating an image forming apparatus according to an embodiment of the present invention. Perspective view with document holding plate open Explanatory drawing of the first and second frames Enlarged view of leaf spring connection The figure which shows the connection method of the 1st, 2nd frame The figure which shows the operating method of the 1st, 2nd frame Figure showing the frame with the document holding plate closed View of the device from below Diagram showing the frame with the document holding plate open Figure showing a conventional example

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Document reading part 101 Image forming part 102 Document reading means 103 Base part 104 Document pressing plate 105 Automatic document feeding mechanism 106 Document stacking part 107a, 107b Document pressing plate rotation center 114 Laser scanner unit 120 First frame 122 Second frame 123a , 123b, 123c, 123d Leaf springs 124, 125 Second frame sheet metal 126a, 126b, 126c, 126d First frame ground member 127a, 127b Second frame ground member 128 Second frame rotation center

Claims (4)

In an image forming apparatus having a document reading unit that reads a document and an image forming unit that forms an image on a recording material,
A first frame that contains and holds the image forming unit, and a second frame that supports the document reading unit, and the second frame is provided outside a range in which the first frame is projected from above. An image forming apparatus, wherein the image forming apparatus is connected to the first frame so as to be displaceable below the apparatus.   The image forming apparatus according to claim 1, wherein the second frame is connected to the first frame so as to be elastically displaceable below the apparatus.   The document reading unit includes a document pressing unit having an automatic document supply unit, the document pressing unit is supported rotatably with respect to the document reading unit, and the rotation center of the document pressing unit is The image forming apparatus according to claim 1, wherein the image forming apparatus is disposed in the second frame.   The second frame includes a grounding member having a gap when the original reading unit is not mounted on a surface on which the image forming apparatus is installed, and the grounding member holds the image forming apparatus when the original reading unit is mounted. The image forming apparatus according to claim 1, wherein the image forming apparatus is grounded on the same surface as the installation surface.

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