Developing device and printer

Abstract

The utility model relates to a developing device which comprises a bracket, the two ends of the photosensitive drum are rotationally supported on the bracket; the developing roller is parallel to the photosensitive drum and two ends of the developing roller are rotatably supported on the bracket; the first elastic piece is arranged on the bracket and elastically pressed at the driving end of the developing roller along the radial direction of the developing roller, and the first elastic piece has a trend of elastically pressing the developing roller towards the photosensitive drum; the second elastic piece is arranged on the bracket and elastically pressed at the non-driving end of the developing roller along the radial direction of the developing roller, and the second elastic piece has a trend of elastically pressing the developing roller towards the photosensitive drum; the elastic force of the second elastic piece is smaller than that of the first elastic piece. The developing device can effectively overcome the left-right gap difference between the photosensitive drum and the developing roller in the transmission process. The utility model further relates to a printer which comprises the developing device. The printer can print images with uniform imaging concentration.

Description

TECHNICAL FIELD

[0001] The utility model relates to a developing device, and the utility model also relates to a printer using the developing device. BACKGROUND

[0002] The developing device is a core component in the printer, and the developing device in the laser printer mainly comprises a toner cartridge, a photosensitive drum, a charging roller and a developing roller. When the laser printer performs a printing work, the charging roller uniformly charges the surface of the photosensitive drum to make the surface of the photosensitive drum obtain a certain potential, and then the photosensitive drum is exposed to a laser beam carrying image information to form an electrostatic latent image on the surface of the photosensitive drum.

[0003] In order to ensure the printing image effect, a relatively stable gap needs to be maintained between the developing roller and the photosensitive drum. However, the current developing device is prone to material shrinkage due to the characteristics of the materials used in the components. The size changes after the material shrinkage, and the gap between the developing roller and the photosensitive drum changes with the material shrinkage. At the same time, the photosensitive drum is easily affected by the gear meshing tension during the driving rotation, which causes the gap between the photosensitive drum and the developing roller at the driving end to increase, while at the non-driving end, the gap between the photosensitive drum and the developing roller becomes smaller due to the pressing force, resulting in inconsistent gap width between the photosensitive drum and the developing roller at the driving end and the non-driving end, and further affecting the printing image effect.

[0004] In addition, as the printing work progresses, carbon powder will scatter at both ends of the developing roller during rotation, which further affects the gap between the developing tube and the photosensitive drum, and further affects the printing image effect. Utility Model Content

[0005] The first technical problem to be solved by the utility model is to provide a developing device that can effectively overcome the gap difference between the photosensitive drum and the developing roller during transmission.

[0006] The second technical problem to be solved by the utility model is to provide a printer that can print images with uniform imaging density.

[0007] The technical solution adopted by the utility model to solve the above-mentioned first technical problem is as follows: A developing device comprises a bracket,

[0008] The photosensitive drum is rotatably supported at both ends on the support frame;

[0009] The developing roller is rotatably supported at both ends on the support frame in parallel to the photosensitive drum;

[0010] The first elastic member is arranged on the support frame and elastically presses the driving end of the developing roller in the radial direction of the developing roller, and has a tendency to elastically press the developing roller towards the photosensitive drum;

[0011] The second elastic member is arranged on the support frame and elastically presses the non-driving end of the developing roller in the radial direction of the developing roller, and has a tendency to elastically press the developing roller towards the photosensitive drum; the elastic pressing force of the second elastic member is smaller than that of the first elastic member.

[0012] In order to facilitate the rotation assembly of the photosensitive drum on the support frame, a hub is connected to the end of the photosensitive drum, a first shaft sleeve is sleeved outside the hub, and the first shaft sleeve is embedded on the support frame.

[0013] In order to effectively solve the problem that the flying carbon powder pollutes the developing roller, and avoid the influence of the flying carbon powder on the gap distance between the developing roller and the photosensitive drum, a second shaft sleeve is sleeved on the end of each end of the developing roller, and the second shaft sleeve is embedded on the support frame.

[0014] The second shaft sleeve extends inward in the axial direction and has an extension part, and the support frame is provided with a cleaning member attached to the outer surface of the extension part.

[0015] In order to facilitate the elastic pressing effect of the elastic member on the developing roller, a bushing is sleeved on the end of each end of the developing roller, the bushing is embedded on the support frame, and the first elastic member and the second elastic member elastically press the bushing at the corresponding end.

[0016] Preferably, the support frame is provided with a mounting groove in communication with the mounting space of the bushing in the elastic pressing direction of the first elastic member and the second elastic member, respectively, and the first elastic member and the second elastic member are arranged in the corresponding mounting groove.

[0017] In order to facilitate the assembly of the elastic member and avoid the displacement of the action point of the elastic member on the developing roller, a protrusion is arranged on the bushing, and the elastic member is positioned relative to the protrusion.

[0018] In order to avoid the displacement of the bushing due to the elastic pressing effect of the elastic member, the outer surface of the bushing has a positioning surface in the form of a plane, and the support frame has a limiting surface matched with the positioning surface.

[0019] In order to further avoid the displacement of the bushing due to the elastic pressing effect of the elastic member, the outer surface of the bushing is provided with a positioning member, and the support frame is provided with a positioning groove for the positioning member.

[0020] The utility model discloses a technical scheme that solves the second technical problem is as follows: a printer, including aforementioned developing device.

[0021] Compared with the prior art, the utility model has the advantages that the developing device in the utility model uses two elastic members with different elastic pressures to act on the driving end and the non-driving end of the developing roller, so as to compensate for the gap difference between the two ends of the photosensitive drum and the developing roller caused by the tensioning force in the transmission process, make the gap between the two ends of the photosensitive drum and the developing roller consistent, and further ensure the uniformity of the left and right developing gaps and improve the uniformity of the left and right concentrations of the printed image.

[0022] The printer applied with the developing device has higher image imaging quality. BRIEF DESCRIPTION OF DRAWINGS

[0023] Fig. 1 It is the perspective view of the developing device in the utility model embodiment.

[0024] Fig. 2 It is the perspective exploded view of the developing device in the utility model embodiment.

[0025] Fig. 3 It is the sectional view of the developing device in the utility model embodiment.

[0026] Fig. 4 It is the sectional view of another section of the developing device in the utility model embodiment. DETAILED DESCRIPTION

[0027] The utility model will be described in further detail in combination with the embodiment of the drawings.

[0028] As Figs. 1 to 4 Indicated, the developing device in the utility model embodiment, including support 1, photosensitive drum 2, developing roller 3, first elastic member 4 and second elastic member 5.

[0029] Wherein support 1 is mainly used for supporting installation photosensitive drum 2, developing roller 3, of course, in order to realize developing work, still support setting has charging roller, cleaning doctor, powder doctor etc. component on support 1. The support 1 determines its form according to the specific design of the internal structure of the printer, simply, support 1 is provided with two oppositely arranged support plates.

[0030] The photosensitive drum 2 is rotatably supported at both ends on the support 1. Specifically, in order to realize driving of the photosensitive drum 2, a wheel hub 21 is connected at least at the driving end of the photosensitive drum 2, and a first shaft sleeve 22 is sleeved outside the wheel hub 21. The limiting structure can adopt various existing structures that can realize relative limiting of two components. In the embodiment, the wheel hub 21 is provided with a stepped surface to realize limiting sleeving of the first shaft sleeve 22 on the wheel hub 21, so as to avoid left and right movement of the first shaft sleeve 22 relative to the wheel hub 21. The first shaft sleeve 22 is embedded on the support 1, thereby realizing rotatable support of the end of the photosensitive drum 2 on the support 1. The non-driving end of the photosensitive drum 2 is provided with or without the wheel hub 21 as needed. When the wheel hub 21 is provided, the assembly mode thereof on the support 1 is the same as that of the driving end. When the wheel hub 21 is not provided, the first shaft sleeve 22 is directly sleeved on the non-driving end of the photosensitive drum 2, and then the rotatable support of the other end of the photosensitive drum 2 on the support 1 is realized through embedding of the first shaft sleeve 22 on the support 1.

[0031] The developing roller 3 is parallel to the photosensitive drum 2 and is rotatably supported at both ends on the support 1. In the embodiment, the second shaft sleeve 31 is sleeved on the end of each of the two ends of the developing roller 3, and the second shaft sleeve 31 is embedded on the support 1. In this way, the rotatable support of the developing roller 3 on the support 1 is realized through the second shaft sleeve 31.

[0032] During printing, with rotation of the developing roller 3, the two ends of the developing roller 3 will be polluted by scattered toner in the non-working area of the two ends of the developing roller 3, and the scattered toner between the developing roller 3 and the end of the photosensitive drum 2 will also affect the spacing between the developing roller 3 and the photosensitive drum 2. In order to solve the problem, the developing device in the embodiment is further provided with a cleaning piece 6 for cleaning the scattered toner at the two ends of the developing roller 3. The cleaning piece 6 can be selected to be cleaning cotton, which has a deformation capability and can be well attached to the outer surface of the end of the developing roller 3 to realize cleaning. Specifically, the second shaft sleeve 31 at each of the two ends extends an extension 310 in the axial direction. The extension 310 is clamped between the end of the developing roller 3 and the end of the photosensitive drum 2. Under the elastic force of the first elastic piece 4 and the second elastic piece 5, the extension 310 abuts against the photosensitive drum 2. The extension 310 can avoid the developing roller 3 and the photosensitive drum 2 being too tightly pressed, so that the gap between the developing roller 3 and the photosensitive drum 2 is always equal to the wall thickness of the extension 310, thereby keeping a relatively stable spacing between the two. The cleaning piece 6 is arranged on the support 1 and is attached to the outer surface of the extension 310. In order to facilitate installation of the cleaning piece 6, an installation piece 14 for installing the cleaning piece can be arranged on the inner side wall of the support 1. The cleaning piece is installed on the installation piece 14.

[0033] As described in the background, the photosensitive drum 2 is susceptible to the gear meshing tension during the driving rotation, resulting in the gap between the photosensitive drum 2 and the developing roller 3 at the driving end increasing, while at the non-driving end, the photosensitive drum 2 and the developing roller 3 are subjected to the pressing force, and the gap between them becomes smaller, thereby causing the gap widths between the photosensitive drum 2 and the developing roller 3 at the driving end and the non-driving end to be inconsistent, and further resulting in the printing density being inconsistent in the image printing. In the embodiment, the problem is solved by the first elastic member 4 and the second elastic member 5.

[0034] The first elastic member 4 is arranged on the bracket 1 and is pressed against the driving end of the developing roller 3 in the radial direction of the developing roller 3, and the first elastic member 4 has a tendency to press the developing roller 3 towards the photosensitive drum 2. The second elastic member 5 is arranged on the bracket 1 and is pressed against the non-driving end of the developing roller 3 in the radial direction of the developing roller 3, and the second elastic member 5 has a tendency to press the developing roller 3 towards the photosensitive drum 2. The pressing force of the second elastic member 5 is smaller than that of the first elastic member 4. The elastic forces of the first elastic member 4 and the second elastic member 5 are determined during the product development stage. Based on the constraint of the pressing forces of the first elastic member 4 and the second elastic member 5, the two ends of the developing roller 3 can compensate for the gap difference between the two ends of the photosensitive drum 2 and the developing roller 3 caused by the tension during the transmission process under the pressing forces of the first elastic member 4 and the second elastic member 5, so that the gap widths of the two ends of the photosensitive drum 2 and the developing roller 3 are consistent.

[0035] In order to facilitate the pressing effect of the elastic members on the developing roller 3, the ends of the developing roller 3 are also sleeved with a bushing 32, which is located outside the second shaft sleeve 31 and is embedded in the bracket 1. The first elastic member 4 and the second elastic member 5 are pressed against the bushing 32 at the corresponding end.

[0036] In order to maintain the stable pressing direction of the first elastic member 4 and the second elastic member 5, the bracket 1 is provided with a mounting groove 11 in communication with the mounting space of the bushing 32 in the pressing direction of the first elastic member 4 and the second elastic member 5, and the first elastic member 4 and the second elastic member 5 are arranged in the corresponding mounting groove 11. The accuracy of the pressing force direction of the first elastic member 4 and the second elastic member 5 is constrained based on the mounting groove 11.

[0037] In addition, in order to facilitate the assembly of the elastic members and avoid the displacement of the action point of the elastic members on the developing roller 3, a protrusion 321 is arranged on the bushing 32, and the elastic members are positioned relative to the protrusion 321. The end of the elastic member can be connected to the protrusion 321 by a fixed connection, or the relative positioning between the elastic member and the protrusion 321 can be achieved by a relative position constraint such as a spring sleeve on the protrusion 321.

[0038] In addition, in order to avoid the rotation displacement of the bushing 32 due to the elastic pressing of the elastic member, the outer surface of the bushing 32 is provided with a positioning surface 322 in a plane, and the support 1 is provided with a limiting surface 12 matched with the positioning surface 322. The outer surface of the bushing 32 can also be provided with a positioning member 323, and the support 1 is provided with a positioning groove 13 for the positioning member 323. Through the above structure, the rotation displacement of the bushing 32 due to the elastic pressing force of the elastic member can be effectively avoided, and the elastic member can only press the photosensitive drum 2 and the developing roller 3 in the direction of the photosensitive drum 2, so as to maintain the consistency of the gap between the photosensitive drum 2 and the developing roller 3 in the left-right direction.

[0039] The developing device in the utility model, use two elastic members of different elastic pressing force to act on the driving end and the non-driving end of the developing roller 3, so as to make up the gap difference between the two ends of the photosensitive drum 2 and the developing roller 3 caused by the tension force in the transmission process, make the gap between the two ends of the photosensitive drum 2 and the developing roller 3 consistent, and further ensure the left-right developing gap uniformity and improve the left-right image density uniformity.

[0040] The utility model also relates to a printer, including preceding developing device, the printer of having applied preceding developing device, image imaging quality is higher.

[0041] In the specification and claims of the utility model, the terms expressing direction, such as "front", "back", "up", "down", "left", "right", "side", "top", "bottom" and the like, are used to describe various example structural parts and elements of the present application, but these terms are only used for the purpose of convenient description, and are determined based on the example orientation shown in the drawings. Since the disclosed embodiments of the present application can be arranged in different directions, these terms expressing direction are only used for description and should not be regarded as limitation, for example, "up" and "down" are not necessarily limited to the direction opposite or consistent with the direction of gravity.

Claims

1. A developing device comprising a bracket (1); a photosensitive drum (2) rotatably supported at both ends on the bracket (1); a developing roller (3) rotatably supported at both ends on the bracket (1) in parallel with the photosensitive drum (2); characterized in that further comprising a first elastic member (4) provided on the bracket (1) and elastically pressing the driving end of the developing roller (3) in the radial direction of the developing roller (3), the first elastic member (4) having a tendency to elastically press the developing roller (3) toward the photosensitive drum (2); a second elastic member (5) provided on the bracket (1) and elastically pressing the non-driving end of the developing roller (3) in the radial direction of the developing roller (3), the second elastic member (5) having a tendency to elastically press the developing roller (3) toward the photosensitive drum (2), the elastically pressing force of the second elastic member (5) being smaller than the elastically pressing force of the first elastic member (4).

2. The developing device according to claim 1, characterized by: An end portion of the photosensitive drum (2) is connected with a hub (21), the hub (21) is externally limitedly sleeved with a first shaft sleeve (22), and the first shaft sleeve (22) is embedded on the bracket (1).

3. The developing device according to claim 1, characterized by: End portions of both ends of the developing roller (3) are each sleeved with a second shaft sleeve (31), and the second shaft sleeve (31) is embedded on the bracket (1). The second shaft sleeve (31) extends inward in the axial direction to have an extension portion (310), and the extension portion (310) is abutted against the photosensitive drum (2) by the first elastic member (4) and the second elastic member (5).

4. The developing device according to any one of claims 1 to 3, characterized by: End portions of both ends of the developing roller (3) are each sleeved with a bushing (32), and the bushing (32) is embedded on the bracket (1), the first elastic member (4) and the second elastic member (5) elastically pressing the bushing (32) at the corresponding end.

5. The developing device according to claim 4, characterized by: The bracket (1) is provided with a mounting groove (11) in communication with the mounting space of the bushing (32) in the elastically pressing direction of the first elastic member (4) and the second elastic member (5), respectively, and the first elastic member (4) and the second elastic member (5) are arranged in the corresponding mounting groove (11).

6. The developing device according to claim 4, characterized by: The bushing (32) is provided with a protrusion (321), and the elastic member is arranged in position relative to the protrusion (321).

7. The developing device according to claim 4, characterized by: An outer surface of the bushing (32) has a planar positioning face (322), and the bracket (1) has a limiting face (12) opposite to and matching the positioning face (322).

8. The developing device according to claim 4, characterized by: An outer surface of the bushing (32) is provided with a positioning member (323), and the bracket (1) is provided with a positioning groove (13) for the positioning member (323) to be arranged in.

9. The developing device according to claim 3, wherein: The bracket (1) is provided with a cleaning member (6) matching and attached to the outer surface of the extension portion (310).

10. A printer characterized by: The developing device comprises any one of claims 1 to 9.

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