Mechanism for preventing paper from being sucked back for printer

Abstract

The utility model relates to a mechanism for preventing paper from being sucked back for a printer, which comprises a printer body, a paper delivery roller, a transmission gear, a cam and a transmission cap, the paper delivery roller can be rotatably arranged on the printer body, and the transmission gear is sleeved on the periphery of the paper delivery roller and is arranged close to the end part of the paper delivery roller; the cam and the transmission cap matched with the transmission gear are arranged at the end of the paper delivery roller, the matching structure forms a roller shaft one-way rotation restraining structure, when the transmission gear rotates forwards, linkage with the paper delivery roller can be achieved through the cam and the transmission cap, and the paper delivery roller rotates forwards along with forward rotation of the transmission gear and corresponds to image printing and paper delivery states. When the transmission gear rotates reversely, the cam is in contact linkage with the transmission cap and the paper delivery roller through axial movement of the cam, and when the transmission gear rotates reversely due to the difference, the paper delivery roller is kept static, so that paper is prevented from being sucked back, and when the paper is not discharged out of the printer, the printing action of the next piece of paper can be carried out, and the printing speed of the printer is increased.

Description

Technical Field

[0001] The utility model relates to the technical field of printers, in particular to a printer paper suction-back prevention mechanism. Background Art

[0002] Printers are widely used, and higher requirements are placed on their performance. Among them, paper jams are common problems in the use of printers. In the prior art, printers mainly improve the paper rubbing part to avoid paper jams caused by repeated paper feeding.

[0003] For example, the Chinese utility model patent "Paper stop mechanism, paper feed unit and image forming device" with authorization announcement number CN204124862U (application number 201420449311.1) discloses a paper stop mechanism that uses a swingable stopper and a paper stopper, thereby preventing paper re-feeding and paper jams through the cooperation of the stopper and the paper stopper. However, since the paper output roller and the transmission gear always rotate synchronously, under human factors or other factors, the paper is easily sucked back into the printer as the transmission gear rotates, thereby causing a paper jam.

[0004] Therefore, further improvements are needed to be made to the current paper suction-back prevention mechanism of the printer. Utility Model Content

[0005] The first technical problem to be solved by the utility model is to provide a printer which can avoid the reversal of the paper output roller and thus solve the problem of paper sucking back in view of the current status of the prior art.

[0006] The technical solution adopted by the utility model to solve the above technical problems is:

[0007] A printer paper sucking back prevention mechanism comprises a printer body, a paper discharge roller, and a transmission gear, wherein the paper discharge roller is rotatably arranged on the printer body, the transmission gear is sleeved on the outer circumference of the paper discharge roller and arranged near the end thereof, and further comprises:

[0008] A cam, wherein the outer end surface of the transmission gear is provided with a shaft sleeve extending outwardly along the paper discharge roller, and the cam is sleeved on the shaft sleeve so as to move circumferentially and axially along the shaft sleeve, and the outer end surface of the transmission gear is also provided with a first limiting tooth arranged around the outer periphery of the shaft sleeve, and correspondingly, the inner end of the cam is provided with a second limiting tooth which can be relatively engaged with or relatively disengaged from the first limiting tooth;

[0009] The transmission cap is arranged at the outer end of the paper discharge roller and rotates synchronously with the paper discharge roller. The outer end of the cam is provided with a third limiting tooth extending outward. Correspondingly, the inner end of the transmission cap is provided with a fourth limiting tooth that can form a circumferential limit with the third limiting tooth.

[0010] Preferably, the first limiting teeth are multiple and arranged at intervals along the circumferential direction on the outer end face of the transmission gear, and the height of each of the first limiting teeth in the axial direction gradually increases along the forward direction of the transmission gear, thereby forming a first limiting step at its end; the second limiting teeth are multiple and arranged at intervals along the circumferential direction on the inner end face of the cam, and the height of each of the second limiting teeth in the axial direction gradually decreases along the forward direction of the transmission gear, and a second limiting step that can be engaged with the first limiting step is formed at its starting end. The above structure is adopted to facilitate the linkage between the transmission gear and the cam as the transmission gear rotates forward, and the cam rotates forward as the transmission gear rotates forward, and then drives the paper output roller to rotate forward through the transmission cap, and this state corresponds to the process of printing images and the process of spitting out paper.

[0011] Preferably, the end surface of the first limiting tooth forms a first guiding inclined surface, and the end surface of the second limiting tooth forms a second guiding inclined surface that can slide and cooperate with the first guiding inclined surface when the transmission gear and the cam are in a state of relative rotation. When the transmission gear is reversed, the two guiding inclined surfaces can slide and cooperate and gradually disengage from each other to eliminate the linkage between the cam and the transmission gear.

[0012] Preferably, the third limiting teeth are multiple and are arranged at intervals along the circumferential direction at the outer end of the cam, and the outer end surface of the cam between two adjacent third limiting teeth forms a third guiding inclined surface that gradually extends toward the direction of the transmission gear along the forward direction of the transmission gear, and the end of the fourth limiting tooth is slidably matched with the third guiding inclined surface. This structure can cooperate with the reverse rotation of the transmission gear to allow the cam to reciprocate along the axial direction, and under the action of the fourth limiting tooth of the transmission cap, it assists in achieving the generation or elimination of the linkage between the cam and the transmission gear.

[0013] Preferably, when the end of the fourth limit tooth corresponds to the highest point of the third guide slope, the first limit step is engaged with the second limit step, and the transmission gear, cam and transmission cap form a paper discharge driving component that drives the paper discharge roller to rotate forward as the transmission gear rotates forward. Preferably, when the end of the fourth limit tooth corresponds to the lowest point of the third guide slope, the first limit step is relatively disengaged from the second limit step, and the transmission gear, cam and transmission cap are relatively separated to form an anti-sucking back component that makes the paper discharge roller stationary as the transmission gear reverses. The above structure is adopted to assist in realizing the generation or elimination of the linkage between the cam and the transmission gear, and switching to the paper discharge state or the anti-sucking back state.

[0014] Preferably, a transmission structure is provided between the inner wall of the cam and the outer wall of the sleeve, which can drive the cam to rotate with the positive rotation of the transmission gear and gradually separate the cam from the sleeve with the reverse rotation of the transmission gear. This structure facilitates driving the cam to move axially with the positive and reverse rotation of the transmission gear, thereby achieving separation or approach of the cam and the transmission gear.

[0015] Preferably, the outer peripheral wall of the sleeve is provided with a first clamping foot close to the first limiting tooth and gradually protruding along the forward rotation direction of the transmission gear, and correspondingly, the inner peripheral wall of the cam is provided with a second clamping foot extending along the axial direction and gradually protruding along the reverse rotation direction of the transmission gear. Preferably, when the first clamping foot is in a state of relative clamping engagement with the second clamping foot as the transmission gear rotates forward, the cam rotates forward along with the transmission gear; when the first clamping foot is in a state of relative disengagement from the second clamping foot as the transmission gear rotates reversely, the cam and the transmission gear are released from linkage.

[0016] In order to facilitate connection, a support seat is provided on the printer body, and the paper discharge roller is rotatably constrained on the support seat by means of a mounting sleeve.

[0017] Compared with the prior art, the utility model has the following advantages: a cam and a transmission cap matched with the transmission gear are arranged at the end of the paper discharge roller of the utility model, and the matching structure constitutes a one-way rotation constraint structure of the roller shaft. When the transmission gear rotates forward, the cam and the transmission cap can be used to realize linkage with the paper discharge roller. The paper discharge roller rotates forward along with the forward rotation of the transmission gear, corresponding to the printing image and paper discharge status. When the transmission gear is reversed, the cam moves axially to contact and link with the transmission cap and the paper discharge roller. When the transmission gear is reversed due to an abnormality, the paper discharge roller remains stationary, thereby preventing the paper from being sucked back, and when the paper is not spit out of the printer, the printing action of the next sheet of paper can be performed, thereby improving the printing speed of the printer. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a partial structural schematic diagram of a printer according to an embodiment of the utility model;

[0019] Figure 2 This is the paper suction-back prevention mechanism (paper output state) of the embodiment of the utility model;

[0020] Figure 3 This is the paper suction-back prevention mechanism (anti-suction-back state) of the embodiment of the utility model;

[0021] Figure 4 This is an assembly diagram of the transmission gear and the cam of the embodiment of the utility model;

[0022] Figure 5 It is a transmission gear diagram of an embodiment of the utility model;

[0023] Figure 6 This is a cam diagram of an embodiment of the utility model. DETAILED DESCRIPTION

[0024] The present invention will be described in further detail below in conjunction with the accompanying drawings.

[0025] like Figures 1 to 6As shown, the printer paper suction prevention mechanism of this embodiment includes a printer body 1, a paper discharge roller 2, a transmission gear 3, a cam 4, a transmission cap 5, a driving wheel 6, a belt 7 and a support seat 8. The paper discharge roller 2 is rotatably arranged on the printer body 1. The support seat 8 is arranged on the printer body 1. The paper discharge roller 2 is rotatably constrained on the support seat 8 by assembling a shaft sleeve 81. The transmission gear 3 is sleeved on the outer periphery of the paper discharge roller 2 and arranged near its end. The driving wheel 6 is arranged at the rear side of the transmission gear 3 and connected to the driving source. The belt 7 is connected between the driving wheel 6 and the transmission gear 3 to drive the transmission gear 3 to rotate.

[0026] The outer end surface of the transmission gear 3 is provided with a shaft sleeve 31 extending outward along the paper discharge roller 2. The cam 4 is sleeved on the shaft sleeve 31 and can move circumferentially and axially along the shaft sleeve 31. The outer end surface of the transmission gear 3 is also provided with a first limiting tooth 32 arranged around the periphery of the shaft sleeve 31. Correspondingly, the inner end of the cam 4 is provided with a second limiting tooth 41 that can be relatively engaged with or relatively disengaged from the first limiting tooth 32; the transmission cap 5 is provided at the outer end of the paper discharge roller 2 and rotates synchronously with the paper discharge roller 2. The outer end of the cam 4 is provided with a third limiting tooth 42 extending outward. Correspondingly, the inner end of the transmission cap 5 is provided with a fourth limiting tooth 51 that can form a circumferential limit with the third limiting tooth 42.

[0027] The first limiting teeth 32 are multiple and arranged at intervals along the circumferential direction on the outer end surface of the transmission gear 3. The height of each first limiting tooth 32 in the axial direction gradually increases along the forward direction of the transmission gear 3, thereby forming a first limiting step 321 at its end; the second limiting teeth 41 are multiple and arranged at intervals along the circumferential direction on the inner end surface of the cam 4. The height of each second limiting tooth 41 in the axial direction gradually decreases along the forward direction of the transmission gear 3, and forms a second limiting step 411 at its starting end that can be engaged with the first limiting step 321. The above structure is adopted to facilitate the linkage between the transmission gear 3 and the cam 4 with the forward rotation of the transmission gear 3. The cam 4 rotates forward with the forward rotation of the transmission gear 3, and then drives the paper discharge roller 2 to rotate forward through the transmission cap 5. This state corresponds to the process of printing images and the process of spitting out paper.

[0028] The end surface of the first limiting tooth 32 forms a first guiding inclined surface 322, and the end surface of the second limiting tooth 41 forms a second guiding inclined surface 412 that can slide with the first guiding inclined surface 322 when the transmission gear 3 and the cam 4 rotate relative to each other. When the transmission gear 3 reverses, the two guiding inclined surfaces can slide and gradually disengage from each other to eliminate the linkage between the cam 4 and the transmission gear 3.

[0029] There are multiple third limiting teeth 42 and they are arranged at intervals along the circumferential direction at the outer end of the cam 4. The outer end surface of the cam 4 between two adjacent third limiting teeth 42 forms a third guiding inclined surface 421 that gradually extends toward the transmission gear 3 along the forward direction of the transmission gear 3. The end of the fourth limiting tooth 51 is slidably matched with the third guiding inclined surface 421. This structure can cooperate with the reverse rotation of the transmission gear 3 to allow the cam 4 to reciprocate along the axial direction. Under the action of the fourth limiting tooth 51 of the transmission cap 5, the linkage between the cam 4 and the transmission gear 3 is assisted to be generated or eliminated.

[0030] When the end of the fourth limiting tooth 51 corresponds to the highest point of the third guiding inclined surface 421, the first limiting step 321 and the second limiting step 411 are engaged with each other, and the transmission gear 3, the cam 4, and the transmission cap 5 form a paper discharge driving assembly that drives the paper discharge roller 2 to rotate forward as the transmission gear 3 rotates forward. When the end of the fourth limiting tooth 51 corresponds to the lowest point of the third guiding inclined surface 421, the first limiting step 321 and the second limiting step 411 are relatively disengaged, and the transmission gear 3, the cam 4, and the transmission cap 5 are relatively separated to form an anti-sucking back assembly that makes the paper discharge roller 2 stationary as the transmission gear 3 reverses. The above structure is adopted to assist in realizing the generation or elimination of the linkage between the cam 4 and the transmission gear 3, and switch to the paper discharge state or the anti-sucking back state.

[0031] A transmission structure is provided between the inner wall of the cam 4 and the outer wall of the shaft sleeve 31, which can drive the cam 4 to rotate with the positive rotation of the transmission gear 3 and can gradually separate the cam 4 from the shaft sleeve 31 with the reverse rotation of the transmission gear 3. This structure facilitates driving the cam 4 to move axially with the positive and reverse rotation of the transmission gear 3, thereby realizing the separation or approach of the cam 4 and the transmission gear 3.

[0032] The outer peripheral wall of the shaft sleeve 31 is provided with a first clamping foot 311 close to the first limiting tooth 32 and gradually protruding along the forward rotation direction of the transmission gear 3. Correspondingly, the inner peripheral wall of the cam 4 is provided with a second clamping foot 43 extending along the axial direction and gradually protruding along the reverse rotation direction of the transmission gear 3. When the first clamping foot 311 is in a state of relative clamping engagement with the second clamping foot 43 as the transmission gear 3 rotates forward, the cam 4 rotates forward with the transmission gear 3; when the first clamping foot 311 is in a state of relative disengagement from the second clamping foot 43 as the transmission gear 3 rotates reversely, the cam 4 and the transmission gear 3 are released from linkage.

[0033] When the structure of this embodiment is used:

[0034] The belt 7 drives the transmission gear 3 to rotate forward, and the transmission gear 3 drives the cam 4 to rotate forward through the transmission structure. At this time, the contact part between the outer side of the cam 4 and the transmission cap 5 will rotate from the lowest point to the highest point. After reaching the highest point of the cam, the positions of the transmission gear 3, the cam 4, and the transmission cap 5 are relatively fixed. Since the transmission cap 5 is fixed on the paper discharge roller 2, the paper discharge roller 2 will realize forward rotation accordingly.

[0035] The belt 7 drives the transmission gear 3 to reverse, and the transmission gear 3 disengages from the cam 4 through the transmission structure while driving it intermittently in a slightly positive direction. At this time, the contact part between the outer side of the cam 4 and the transmission cap 5 will rotate from the highest point to the lowest point. After reaching the lowest point of the cam 4, the cam 4 and the transmission gear 3 are in a circumferential contact linkage state, and the transmission gear 3 reverses, but the cam 4 remains stationary, and the paper output roller 2 fixed to the transmission cap 5 will also remain stationary.

[0036] With the above structure, even if the paper with the image printed on it is not ejected out of the printer normally due to human factors or other factors, it will not be sucked back into the printer, and the printer will not have malfunctions such as paper jams.

[0037] In the specification and claims of the present invention, terms indicating directions, such as "front", "rear", "up", "down", "left", "right", "side", "top", "bottom", etc., are used to describe various exemplary structural parts and elements of the present invention, but these terms are used here only for the purpose of convenience of description and are determined based on the exemplary orientations shown in the accompanying drawings. Since the embodiments disclosed in the present invention can be arranged in different directions, these terms indicating directions are only used as explanations and should not be regarded as limitations. For example, "up" and "down" are not necessarily limited to directions opposite to or consistent with the direction of gravity.

Claims

1. A printer paper suction prevention mechanism, comprising a printer body (1), a paper discharge roller (2), and a transmission gear (3), wherein the paper discharge roller (2) is rotatably arranged on the printer body (1), and the transmission gear (3) is sleeved on the outer circumference of the paper discharge roller (2) and arranged near the end thereof, characterized in that: Also includes A cam (4), the outer end surface of the transmission gear (3) is provided with a shaft sleeve (31) extending outwardly along the paper discharge roller (2), the cam (4) is sleeved on the shaft sleeve (31) and can move circumferentially and axially along the shaft sleeve (31), the outer end surface of the transmission gear (3) is also provided with a first limiting tooth (32) arranged around the outer periphery of the shaft sleeve (31), and correspondingly, the inner end of the cam (4) is provided with a second limiting tooth (41) that can be relatively engaged with or relatively disengaged from the first limiting tooth (32); A transmission cap (5) is arranged at the outer end of the paper discharge roller (2) and rotates synchronously with the paper discharge roller (2); the outer end of the cam (4) is provided with a third limiting tooth (42) extending outward; correspondingly, the inner end of the transmission cap (5) is provided with a fourth limiting tooth (51) capable of forming a circumferential limit with the third limiting tooth (42).

2. The printer paper suction prevention mechanism according to claim 1, characterized in that: The first limiting teeth (32) are multiple and are arranged at intervals along the circumferential direction on the outer end surface of the transmission gear (3); the axial height of each of the first limiting teeth (32) gradually increases along the forward rotation direction of the transmission gear (3) to form a first limiting step (321) at its end; the second limiting teeth (41) are multiple and are arranged at intervals along the circumferential direction on the inner end surface of the cam (4); the axial height of each of the second limiting teeth (41) gradually decreases along the forward rotation direction of the transmission gear (3) to form a second limiting step (411) at its starting end that can be engaged with the first limiting step (321) for limiting.

3. The printer paper suction prevention mechanism according to claim 2, characterized in that: The end surface of the first limiting tooth (32) forms a first guiding inclined surface (322), and the end surface of the second limiting tooth (41) forms a second guiding inclined surface (412) which can be slidably matched with the first guiding inclined surface (322) when the transmission gear (3) and the cam (4) are in a state of relative rotation.

4. The printer paper suction prevention mechanism according to claim 2, characterized in that: The third limiting teeth (42) are multiple and are arranged at intervals along the circumferential direction at the outer end of the cam (4); the outer end surface of the cam (4) between two adjacent third limiting teeth (42) forms a third guiding inclined surface (421) that gradually extends toward the transmission gear (3) along the forward rotation direction of the transmission gear (3); and the end of the fourth limiting tooth (51) is slidably matched with the third guiding inclined surface (421).

5. The printer paper suction prevention mechanism according to claim 4, characterized in that: When the end of the fourth limiting tooth (51) corresponds to the highest point of the third guiding inclined surface (421), the first limiting step (321) and the second limiting step (411) are engaged with each other, and the transmission gear (3), the cam (4) and the transmission cap (5) form a paper discharge driving assembly that drives the paper discharge roller (2) to rotate forwardly as the transmission gear (3) rotates forwardly.

6. The printer paper suction prevention mechanism according to claim 4, characterized in that: When the end of the fourth limiting tooth (51) corresponds to the lowest point of the third guiding inclined surface (421), the first limiting step (321) is relatively disengaged from the second limiting step (411), and the transmission gear (3) is relatively separated from the cam (4) and the transmission cap (5) to form an anti-sucking component in which the paper output roller (2) is stationary as the transmission gear (3) reverses.

7. The printer paper suction prevention mechanism according to any one of claims 1 to 6, characterized in that: A transmission structure is provided between the inner wall of the cam (4) and the outer wall of the shaft sleeve (31), which can drive the cam (4) to rotate as the transmission gear (3) rotates forward, and can gradually separate the cam (4) from the shaft sleeve (31) as the transmission gear (3) rotates reversely.

8. The printer paper suction prevention mechanism according to claim 7, characterized in that: The outer peripheral wall of the shaft sleeve (31) is provided with a first clamping foot (311) close to the first limiting tooth (32) and gradually protruding along the forward rotation direction of the transmission gear (3); correspondingly, the inner peripheral wall of the cam (4) is provided with a second clamping foot (43) extending in the axial direction and gradually protruding along the reverse rotation direction of the transmission gear (3).

9. The printer paper suction prevention mechanism according to claim 8, characterized in that: When the first clamping pin (311) rotates forwardly with the transmission gear (3) and is relatively engaged with the second clamping pin (43), the cam (4) rotates forwardly with the transmission gear (3); when the first clamping pin (311) rotates backward with the transmission gear (3) and is relatively disengaged from the second clamping pin (43), the cam (4) and the transmission gear (3) are disengaged.

10. The printer paper suction prevention mechanism according to any one of claims 1 to 6, characterized in that: The printer body (1) is provided with a support seat (8), and the paper discharge roller (2) is rotatably constrained on the support seat (8) by means of a mounting shaft sleeve (31).

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