Developing device and laser printer

Abstract

The utility model relates to a developing device which comprises a photosensitive drum and a developing roller which are arranged in parallel, and plate bodies are respectively clamped between two ends of the photosensitive drum and the developing roller. According to the developing device, the plate body is clamped between the end parts of the photosensitive drum and the developing roller, so that the gap distance between the photosensitive drum and the developing roller is ensured, and the gap distance between the photosensitive drum and the developing roller can be controlled through the thickness of the plate body. The plate body product has multiple thickness specifications, low price and extremely high longitude. And compared with a circular ring structure, the grinding tool processing cost and the size control of the plate body have great advantages, and the control difficulty of mass production is low.

Description

Technical Field

[0001] The utility model relates to a developing device and also to a laser printer using the developing device. Background Art

[0002] A laser printer is a commonly used type of printer. Its working principle is to use a laser to scan the pattern to be printed on the surface of the photosensitive drum, then use electrostatic attraction to adsorb the coloring powder to form a pattern on the photosensitive drum, and finally fix it on the paper through heating and pressure to complete the printing.

[0003] Laser printers utilize different developing methods, with different developing device structures. Currently, there are two main developing methods used in laser printers: contact and non-contact. Non-contact development involves maintaining a constant gap between the photosensitive drum and developing roller in the developing device, without contact. This method offers advantages such as low torque, minimal wear, low cost, and high operational stability.

[0004] Currently, the primary method for maintaining this gap is to use a self-lubricating material, injection-molded into circular sleeves on both ends of the developer roller. By applying a certain pressure, the photosensitive drum and developer roller are brought close together and maintain a constant distance. Specifically, the photosensitive drum and developer roller are separated by circular sleeves, which are freely mounted on the outer diameters of the developer roller at both ends and rotate freely on aluminum tubes. A spring is installed between the powder hopper and the waste toner bin, and a connecting pin connects the two bins. As can be seen from the above structure, the circular sleeves separate the developer roller and the photosensitive drum. The spring force keeps the sleeves tightly attached to the photosensitive drum, ensuring a stable gap between the two rollers during printing. However, this circular sleeve structure presents the following issues. During the product development phase, gap-maintaining rings of various thicknesses must be evaluated and tested to select the optimal thickness. This requires designing molds of varying specifications to produce samples of varying thicknesses, which increases R&D costs and development time. In addition, since the gap between the photosensitive drum and the developing roller needs to be precisely controlled, the thickness of the ring needs to be controlled within a small tolerance range in all directions of the circumference, which also poses great challenges in the mass production control of the product. Utility Model Content

[0005] The first technical problem to be solved by the present invention is to provide a developing device that can stably control the distance between the photosensitive drum and the developing roller and has low difficulty in mass production control in response to the above-mentioned prior art.

[0006] The second technical problem to be solved by the present invention is to provide a laser printer using the aforementioned developing device in response to the above-mentioned prior art.

[0007] The technical solution adopted by the present invention to solve the first technical problem is: a developing device, comprising a photosensitive drum and a developing roller arranged in parallel, with a plate body sandwiched between the ends of the photosensitive drum and the developing roller.

[0008] In order to facilitate assembly, a frame assembly is also included. The frame assembly includes two frames arranged opposite to each other, and the photosensitive drum and the developing roller are rotatably arranged between the two frames.

[0009] As an improvement, first mounting holes are provided on the frame bodies at positions corresponding to the photosensitive drums, and both ends of the photosensitive drums are rotatably supported in the first mounting holes of the two frame bodies through first flanges.

[0010] As an improvement, a second mounting hole is provided on the frame body at a position corresponding to the setting position of the developing roller, and an annular bracket matching the second mounting hole is provided in the second mounting hole, and both ends of the developing roller are rotatably supported in the annular bracket through second flanges respectively;

[0011] The two frames are respectively provided with elastic members that press against the annular bracket. The elastic members have a tendency to press the annular bracket toward the photosensitive drum along a set straight line. The set straight line is a line connecting the first mounting hole and the second mounting hole.

[0012] In order to prevent the annular bracket from excessive displacement, a protrusion is provided on the outer surface of the annular bracket, and the two bracket bodies are respectively provided with a limiting groove for the protrusion on the corresponding annular bracket to be placed.

[0013] In order to effectively guide the pressing direction of the elastic member, guide grooves are provided on both frames along a set straight line direction, and the elastic member is arranged in the guide grooves.

[0014] Simply, the plate body is fixed on the frame body.

[0015] Preferably, mounting pieces are protrudingly provided on the inner surface of the frame at positions corresponding to between the photosensitive drum and the developing roller, and the plate body is fixed on the mounting pieces.

[0016] In order to facilitate the rapid installation of the plate body, the cross-section of the plate body is L-shaped, and the plate body includes a first plate surface and a second plate surface that are relatively vertical. The first plate surface is attached and fixed on the mounting member and clamped between the ends of the photosensitive drum and the developing roller. The second plate surface is attached to the inner surface of the frame. A limiting member is also provided on the inner surface of the frame, and a limiting hole is opened on the second plate surface for the limiting member to be inserted into.

[0017] The technical solution adopted by the present invention to solve the second technical problem is: a laser printer including the aforementioned developing device.

[0018] Compared with the prior art, the advantages of the present invention are as follows: the developing device and the laser printer using the developing device employ a plate sandwiched between the ends of the photosensitive drum and the developing roller to ensure a gap between them. Furthermore, the gap between the photosensitive drum and the developing roller can be controlled by the thickness of the plate. The plate offers a wide range of thicknesses, is inexpensive, and has high reliability. Furthermore, the plate offers significant advantages in mold processing costs and dimensional control over a circular ring structure, making mass production easier to manage. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a three-dimensional diagram of the developing device in the embodiment of the present utility model.

[0020] Figure 2 This is an exploded view of the developing device in the embodiment of the present utility model. DETAILED DESCRIPTION

[0021] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0022] like Figure 1 and Figure 2 As shown, the developing device in this embodiment includes a photosensitive drum 1, a developing roller 2, and a frame assembly.

[0023] The frame assembly includes two frames 4 spaced apart from each other, and the photosensitive drum 1 and the developing roller 2 are rotatably mounted between the two frames 4 in parallel.

[0024] Due to the working principle of the photosensitive drum 1 and the developing roller 2, a certain distance must be maintained between them. The required distance varies for developing devices of different sizes. Plates 3 are sandwiched between the ends of the photosensitive drum 1 and the developing roller 2. The thickness of these plates 3 controls the distance between the two rollers.

[0025] The specific installation structure of each component in the developing device is as follows.

[0026] The two frames 4 in the frame assembly are fixedly mounted within the printer body. First mounting holes 41 are defined on each frame 4, corresponding to the locations where the photosensitive drum 1 is mounted. The ends of the photosensitive drum 1 are rotatably supported within the first mounting holes 41 of the two frames 4 via first flanges 11, thereby securing the photosensitive drum 1 to the two frames 4.

[0027] The frame 4 has a second mounting hole 42 at the location corresponding to the developer roller 2. An annular bracket 43 is provided within the second mounting hole 42, matching the second mounting hole 42. The two ends of the developer roller 2 are rotatably supported within the annular bracket 43 via the second flange 21. However, the direct axial positioning structure of the first and second mounting holes 41 and 42 can lead to looseness or a loose fit due to tolerances, which can cause spacing errors between the photosensitive drum 1 and the developer roller 2. Therefore, to avoid the impact of tolerances on assembly accuracy and ensure the stability and accuracy of the spacing between the photosensitive drum 1 and the developer roller 2, in this embodiment, the developer roller 2 is elastically supported within the second mounting hole 42, allowing the developer roller 2 to move less radially relative to the photosensitive drum 1. The elastic pressure of the elastic support structure, combined with the structure of the plate 3 at the end, maintains a stable spacing position of the developer roller 2 relative to the photosensitive drum 1. Specifically, the two frames 4 are respectively provided with elastic members 5 that rest against the annular bracket 43. The elastic members 5 have a tendency to press the annular bracket 43 toward the photosensitive drum 1 along a set straight line. The set straight line is the line connecting the first mounting hole 41 and the second mounting hole 42 on the same frame 4.

[0028] In order to limit the range of movement of the annular bracket 43 along the set linear direction and prevent the annular bracket 43 from rotating and affecting the biasing direction of the elastic member 5, a protrusion 431 is provided on the outer surface of the annular bracket 43. The two frames 4 are each provided with a limiting groove 44 for receiving the corresponding protrusion 431 on the annular bracket 43. In this embodiment, the limiting groove 44 is slightly wider than the width of the protrusion 431, thereby ensuring the range of movement of the annular bracket 43 along the set linear direction while also limiting the rotation of the annular bracket 43. In other words, the constraint of the protrusion 431 by the limiting groove 44 effectively ensures the relative stability of the biasing direction of the elastic member 5, further ensuring that the developing roller 2 can maintain a tight pressure against the photosensitive drum 1 when installed on the frame 4. At the same time, based on the thickness of the plate 3, the spacing between the developing roller 2 and the photosensitive drum 1 can be maintained stably at the thickness of the plate 3.

[0029] At the same time, to facilitate the installation of the elastic member 5 and effectively maintain the direction of the elastic force of the elastic member 5, guide grooves 45 are provided on both frames 4 along a predetermined linear direction, and the elastic member 5 is disposed within the guide grooves 45. To facilitate the assembly of the elastic member 5, the guide grooves 45 are provided with a first positioning member 451, on which one end of the elastic member 5 is positioned. A second positioning member 432 is provided on the outer surface of the annular bracket 43, on which the other end of the elastic member 5 is positioned.

[0030] In addition, to facilitate the fixing of the plate 3 and prevent it from falling, in this embodiment, the plate 3 is fixed to the frame 4. Specifically, mounting members 40 are protruding from the inner surface of the frame 4 at positions corresponding to the positions between the photosensitive drum 1 and the developing roller 2, and the plate 3 is fixed to the mounting members 40.

[0031] In order to quickly assemble the plate body 3 so that the plate body 3 is located in a position attached to the surface of the photosensitive drum 1, improvements have been made to the shape of the plate body 3 and its mounting structure in this embodiment. Specifically, the cross-section of the plate body 3 is L-shaped, and the plate body 3 includes a first plate surface 31 and a second plate surface 32 that are relatively perpendicular. The first plate surface 31 is attached to the mounting member 40 and is clamped between the ends of the photosensitive drum 1 and the developing roller 2. The second plate surface 32 is attached to the inner surface of the frame 4. A limiting member 46 is also provided on the inner surface of the frame 4. The second plate surface 32 is provided with a limiting hole 321 for the limiting member 46 to be inserted into. When assembling the plate body 3, the limiting hole 321 on the plate body 3 is aligned with the limiting member 46 on the frame 4, and then the second plate surface 32 of the plate body 3 is attached to the inner surface of the plate body 3 so that the limiting member 46 is inserted into the limiting hole 321. At the same time, the first surface 31 of the plate body 3 is attached and fixed to the mounting member 40, thus quickly achieving the positioning and installation of the plate body 3. After the plate body 3 is fixed, the second surface 32 of the plate body 3 is exactly located between the photosensitive drum 1 and the developing roller 2. After the photosensitive drum 1 and the developing roller 2 are both installed on the frame 4, the developing roller 2 is attached to the second surface 32 of the plate body 3 via the elastic member 5, so that the photosensitive drum 1 and the developing roller 2 clamp the second surface 32 of the plate body 3. In this way, the distance between the photosensitive drum 1 and the developing roller 2 is stably maintained at the thickness of the plate body 3.

[0032] This developing device utilizes a plate 3 sandwiched between the ends of the photosensitive drum 1 and the developing roller 2 to maintain the gap between them. The gap can also be controlled by the thickness of the plate 3. The plate 3 is available in a variety of thicknesses and specifications, is inexpensive, and offers excellent stability. Furthermore, the plate 3 offers significant advantages in mold processing costs and dimensional control over a circular ring structure, making mass production easier.

[0033] The utility model also relates to a laser printer, comprising the aforementioned developing device.

[0034] In the specification and claims of the present invention, directional terms such as "front," "back," "up," "down," "left," "right," "side," "top," and "bottom" are used to describe various exemplary structural parts and elements of the present invention. However, these terms are used herein for convenience of description only and are based on the exemplary orientations shown in the accompanying drawings. Since the embodiments disclosed herein can be arranged in different orientations, these directional terms are intended for illustrative purposes only and should not be construed as limiting. For example, "up" and "down" are not necessarily limited to directions opposite to or consistent with the direction of gravity.

Claims

1. A developing device comprising a photosensitive drum (1) and a developing roller (2) arranged in parallel, characterized in that: A plate body (3) is respectively sandwiched between the two ends of the photosensitive drum (1) and the developing roller (2); It also includes a frame assembly, the frame assembly includes two frames (4) arranged opposite to each other, and the photosensitive drum (1) and the developing roller (2) are rotatably arranged between the two frames (4); The plate body (3) is fixed on the frame body (4); a mounting member (40) is protruded on the inner surface of the frame body (4) at a position corresponding to the position between the photosensitive drum (1) and the developing roller (2); and the plate body (3) is fixed on the mounting member (40); The cross section of the plate body (3) is L-shaped, and the plate body (3) includes a first plate surface (31) and a second plate surface (32) which are relatively vertical. The first plate surface (31) is attached to and fixed on the mounting member (40) and is clamped between the ends of the photosensitive drum (1) and the developing roller (2). The second plate surface (32) is attached to the inner surface of the frame (4). A limiting member (46) is also provided on the inner surface of the frame (4). A limiting hole (321) is provided on the second plate surface (32) for the limiting member (46) to be inserted into.

2. The developing device according to claim 1, wherein: The frame (4) is provided with a first mounting hole (41) corresponding to the location of the photosensitive drum (1), and both ends of the photosensitive drum (1) are rotatably supported in the first mounting holes (41) of the two frames (4) through first flanges (11).

3. The developing device according to claim 1, wherein: The frame (4) is provided with a second mounting hole (42) at a position corresponding to the setting position of the developing roller (2); an annular bracket (43) matching the second mounting hole (42) is provided in the second mounting hole (42); and both ends of the developing roller (2) are rotatably supported in the annular bracket (43) via a second flange (21); The two frames (4) are respectively provided with elastic members (5) that abut against the annular bracket (43), and the elastic members (5) have a tendency to press the annular bracket (43) toward the photosensitive drum (1) along a set straight line, and the set straight line is a line connecting the first mounting hole (41) and the second mounting hole (42).

4. The developing device according to claim 3, wherein: A protrusion (431) is provided on the outer surface of the annular bracket (43), and the two bracket bodies (4) are respectively provided with a limiting groove (44) for the protrusion (431) on the corresponding annular bracket (43) to be placed.

5. The developing device according to claim 3, wherein: Both frames (4) are provided with guide grooves (45) along a set straight line direction, and the elastic member (5) is arranged in the guide grooves (45).

6. A laser printer, characterized in that: The developing device comprises the developing device according to any one of claims 1 to 5.

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