Duplexing Gear Unit for Office Equipment

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Amberly Webster
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1 NTN TEHNIL REVIEW No New Product uplexing Gear Unit for Office Equipment Tsutomu MIW uplex printing is widely used in current copy machines and printers as a measure to protect the environment. Those copy machines and printers generally use reversal mechanisms to reverse paper by using forward and reverse rotation of the paper feed roller. NTN has developed a uplexing Gear Unit for Office Equipment without using an electric motor for forward and reverse rotation. This new unit only uses one-way rotation, which is created by another drive system. This report introduces the structure and function of this product. 1. Foreword uplex printing-photocopying machine and printer models are increasingly marketed for their ability to help reduce paper consumption as well as contribute to environmental conservation. For duplex printing, a reversal mechanism is necessary for reversing the paper stock. With a typical reversal mechanism, a paper stock having undergone printing on its front side is switched back by reversing the running direction of the drive motor to the paper feed roller and then printing is resumed on the back side of paper stock. NTN has developed a unique uplexing Gear Unit for office equipment that would replace a motor dedicated to the reversal mechanism and a drive motor component such as a fusing section used to mechanically switch the direction of rotation reducing energy consumption and cost. The uplexing Gear Unit is available in two types, each having unique input scheme. They are two-input one-output type (hereinafter two-input duplexing gear unit ) and one-input one-output type (hereinafter oneinput duplexing gear unit ) (Table 1). 2. Explanation of two-input duplexing gear unit 2.1 escription of operation 1) forward rotation mode When the first input gear is turned in the forward direction, the spring clutch locks the first input gear, causing the output gear engaged with the spring clutch to turn in the forward direction. uring this course, the second reverse input gear turns in the forward direction together with the output gear (Fig. 1). 2) reverse rotation mode When the second input gear is turned in the reverse direction, it comes into contact with the unlock hook of the spring clutch, causing the diameter of spring clutch to reduce. s a result, the spring clutch is unlocked; thereby interrupting drive power transmission from the first input gear to the output gear. When the second input gear is further turned, it comes into contact with the output gear while reducing the diameter of the spring clutch and unlocking the spring clutch, causing the output gear to turn in the reverse direction (Fig. 2). pplication Engineering ept. Industrial Sales headquarters -129-

rotation] [forward rotation] ppearance -130- imensions Features Gear O 26 overall length 28 mm This type consists of three gears first input gear, output gear and second input gear.

2 NTN TEHNIL REVIEW No Table 1 Summary of direction change unit Two-input uplexing Gear Unit (two-input one-output type) One-input uplexing Gear Unit (one-input one-output type) [reverse rotation] [forward rotation] [forward rotation] ppearance imensions Features Gear O 26 overall length 28 mm This type consists of three gears first input gear, output gear and second input gear. When the first input gear turns in the forward direction, the output gear turns in the direction same as that of the first input gear [forward rotation]. Next, when the second input gear turns in the reverse direction, the output gear can turn in the direction same as that of the second input gear, regardless of the rotation direction of the first input gear [reverse rotation]. Gear O 30 overall length 44 mm This type consists of three gears (first) input gear, output gear and control gear. When the control gear is allowed to freely rotate and the input gear is turned in the forward direction, the control gear turns in the direction same as that of the output gear [forward rotation]. Incidentally, when the control gear is braked to stop its rotation (locked state), the output gear turns in the reverse direction [reverse rotation]. Note that the control gear is braked with a solenoid or forward rotation mode Engagement point of spring clutch with output gear (engaged with spring clutch, and turns in the forward direction) of first input gear O Fig. 1 Forward rotation of two input type direction change unit reverse rotation mode Unlock hook (spring clutch) (comes into contact with second input gear, and turns) of first input gear of second input gear ( reduces its diameter.) Unlock and torque transmission section (second input gear) Fig. 2 Reverse rotation of two input type direction change unit O

intermediate shaft engaged with the spring clutch to turn in the forward direction and the output gear to turn in the forward direction as well.

3 uplexing Gear Unit for Office Equipment 3. Explanation of one-input duplexing gear unit 3.1 escription of operation 1) forward rotation mode (control gear in free state) When the input gear is turned in the forward direction, the spring clutch locks the input gear, causing the intermediate shaft engaged with the spring clutch to turn in the forward direction and the output gear to turn in the forward direction as well. Note, however, that the braking means for the control gear is in the OFF state (free state) (Fig. 3). 2) forward rotation mode When the control gear is braked (locked state) by a braking pawl (*1), the unlock hook on the spring clutch comes into contact with the control gear, reducing the diameter of spring clutch: consequently, the spring clutch is unlocked blocking the transmission of drive power from the input gear to the output gear. When the input gear is further turned while the control gear remains in the braked state, the intermediate shaft stops rotation. s a result, the bevel gears rotate, causing the output gear to rotate in the reverse direction (Fig. 4). NOTE: Braking pawl (*1) is not included in the uplexing Gear Unit proper. n actual braking pawl requires use of a solenoid or forward rotation mode (control gear in free state) Engagement point of spring clutch with output gear of input gear (engaged with spring clutch, and turns in the forward direction) Braking pawl Fig. 3 Forward rotation of one input type direction change unit Intermediate shaft Bevel gear O ( in free state) forward rotation mode Unlock hook (spring clutch) Rotation of intermediate shaft stops. of input gear ( reduces its diameter.) Unlock section (control gear) Braking pawl Fig. 4 Reverse rotation of one input type direction change unit Intermediate shaft Bevel gear Bevel gears rotate. O Brake ON -131-

NTN TEHNIL REVIEW No.76 2008 4. Endurance test Endurance of each uplexing Gear Unit has been checked under NTN endurance test conditions (Table 2).

torque 0.1N m 0.1N m One cycle 3 sec. FW BW 3 sec. 3 sec. FW BW 3 sec. Endurance test rigs for uplexing Gear Unit are shown in Figs. 5 and 6 (Fig. 5 for two-input type, and Fig. 6 for one-input type).

4 NTN TEHNIL REVIEW No Endurance test Endurance of each uplexing Gear Unit has been checked under NTN endurance test conditions (Table 2). Table 2 Test condition of Endurance test (Test condition of NTN) ondition 1 (two-input) ondition 2 (one-input) Rotating speed 300min min -1 mbient temperature 100 Ordinary temperature Load torque 0.1N m 0.1N m One cycle 3 sec. FW BW 3 sec. 3 sec. FW BW 3 sec. Endurance test rigs for uplexing Gear Unit are shown in Figs. 5 and 6 (Fig. 5 for two-input type, and Fig. 6 for one-input type). The endurance test rig for two-input uplexing Gear Unit in Fig. 5 uses two motors the first input gear and the second input gear. Reverse rotation cycles are provided by disengagement and engagement with an The endurance test rig for one-input uplexing Gear Unit in Fig. 6 uses only one motor--the input gear. The brake for control gear is applied and released by an electromagnetic brake. Two-input uplexing Gear Unit Output-side load limiter (forward rotation) Reverse input gear electromagnetic clutch (reverse rotation) Fig. 5 Endurance test machine of two input type direction change unit One-input uplexing Gear Unit Output-side load limiter (forward rotation) electromagnetic brake Fig. 6 Endurance test machine of one input type direction change unit -132-

5 uplexing Gear Unit for Office Equipment 4.1 Test result Table 3 summarizes the results of endurance test. NTN studied the operation appearance quality of samples that underwent 300 thousands cycles (endurance requirement for ordinary printers), and learned that all the gears are free from any damage or fracture and function normally. 5. onclusion Society will increasingly become eco-conscience oriented. In this context, duplex printing function will be increasingly adopted even for less expensive photo copying machines and printers as this function can help reduce paper consumption. onsequently, there will be growing needs for cost reduction with the costs of components used for producing this function. The uplexing Gear Unit for office equipment NTN has recently developed is a unique product intended to serve for ecological conservation and value addition, and is characterized in that an electric motor dedicated to duplex printing is eliminated, paper feed direction can be mechanically switched over between forward direction and reverse direction, thereby duplex printing mechanism is available at a lower cost. NTN will further reduce cost, improve performance and propose new applications; thereby NTN will contribute to improve the environment and value. Table 3 Test results Two-input Gearing has certain degree of fouling, but each gear poses no problem. One-input Gearing has certain degree of fouling, but each gear poses no problem. ppearance after test Exterior state Operation quality Light contact has occurred on the outer circumference: no deformation at all. No problem with both forward rotation and reverse rotation Light contact has occurred on the outer circumference: no deformation at all. No problem with both forward rotation and reverse rotation Photo of author Tsutomu MIW pplication Engineering ept. Industrial Sales headquarters -133-

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