JP4535030B2 - Pendulum gear mechanism - Google Patents

Description

The present invention relates to a pendulum gear mechanism including a pendulum gear, and more particularly to a pendulum gear mechanism that can be easily assembled.

In the printer, it is necessary to perform a so-called jam processing for removing paper when a paper jam occurs in the paper transport mechanism. As one method for enabling jam processing, a pendulum gear is provided in the gear train of the paper transport mechanism, and the pendulum gear is separated from the gear train by rotating the motor that drives the paper transport mechanism in reverse. It has been known. By separating the pendulum gear from the gear train, a part of the rollers of the paper transport mechanism becomes free, and the jammed paper can be pulled out.

  Unlike the normal gear, the pendulum gear must be mounted so that the shaft can be moved. When the paper transport mechanism is assembled, it cannot be temporarily fixed. Depending on the assembly method, it may be difficult to assemble the paper transport mechanism. There is.

  An object of the present invention is to provide a pendulum gear mechanism that can temporarily fix a pendulum gear and that can be easily assembled.

In order to achieve this object, the invention described in claim 1 includes a pendulum gear (121), a mounting plate (GP) that movably supports a shaft (121a) of the pendulum gear (121), a pendulum gear ( 121) always attached to the first gear (103), the second gear (122) capable of meshing with the pendulum gear (121), and the mounting plate (GP), and the shaft ( A friction member (141) that contacts the pendulum gear (121) at a position facing the first gear (103) across 121a) and applies a frictional force to the pendulum gear (121) in the rotation direction of the pendulum gear ; Depending on the rotation direction of the first gear (103), the pendulum gear (121) is engaged between a meshing position where it meshes with the second gear (122) and a separation position where it does not mesh with the second gear (122). Move and pendulum gear 121) is formed with a flange (121d) protruding from its tooth surface, and a pendulum gear (121) temporarily fixed to the mounting plate (GP) is connected to the first gear (121) via the collar (121d). The pendulum gear (121) is prevented from falling by being hooked on.

  In this invention, since the fall of the temporarily fixed pendulum gear (121) is prevented using the collar (121d), the assembling work is facilitated.

  In the pendulum gear mechanism according to claim 1, as in claim 2, the collar (121d) may be formed at the end of the pendulum gear (121) on the side of the mounting plate (GP).

  3. The pendulum gear mechanism according to claim 1 or 2, wherein the first gear (103), the pendulum gear (121), and the second gear (122) are provided in the paper transport mechanism of the printer. You may make it comprise a gear train.

  The pendulum gear mechanism according to claim 3, wherein the first gear (103), the pendulum gear (121), and the second gear (122) are included in the paper transport mechanism of the printer. You may make it comprise these gear trains.

  In order to facilitate understanding of the present invention, reference numerals in the accompanying drawings are appended in parentheses, but the present invention is not limited to the illustrated embodiment.

Hereinafter, an embodiment in which the pendulum gear mechanism according to the present invention is applied to a paper transport mechanism of a laser beam printer will be described with reference to FIGS.

  FIG. 1 is a cross-sectional view showing an example of a laser beam printer in which the gear of the present embodiment is used. As shown in FIG. 1, a paper feed cassette 10 for storing stacked paper is mounted at the lower part of the laser beam printer 1. The paper feed cassette 10 is detachable and can be taken out by pulling it out in the direction of arrow P through the handle 13. The paper pressing plate 12 of the paper feeding cassette 10 is biased upward by a pressing spring (not shown), whereby the uppermost layer of paper stacked on the paper pressing plate 12 is provided in the main body of the printer 1. The sheet feeding roller 14 is rotated so as to rotate in the direction indicated by the arrow, and only one sheet is separated and fed by the action of the separation pad 15.

  A process cartridge 20 is disposed above the paper feed cassette 10. The process cartridge 20 is also detachable in the same manner as the paper feed cassette 10 and is pulled out in the direction of arrow Q when the toner is replaced. The process cartridge 20 is a scorotron type that contacts the paper and transfers the toner, a transfer roller 22 that faces the photosensitive drum 21, and a corona discharge to charge the surface of the photosensitive drum 21 to a positive potential. Development cartridge comprising a photosensitive member cartridge 20A having a charger 28, a developer chamber 24 in which toner is accumulated, a developing roller 25 for supplying toner to the photosensitive drum 21, and a supply roller 27 for supplying toner to the developing roller 25. 20B. The developer chamber 24 is provided with an agitator 24a for stirring the toner.

  The photosensitive cartridge 20A and the developing cartridge 20B can be disassembled from each other. However, when the process cartridge 20 is removed from the main body of the printer 1, both are pulled out in an integrated state. On the front side of the printer 1, there is provided a cover 33 whose lower end is rotatably attached to a rotary shaft 33a. The cover 33 is rotated clockwise in FIG. 2 to open the front side of the printer 1. Thus, the process cartridge 20 can be attached and detached.

  As shown in FIG. 1, a pair of registration rollers 31 and a registration roller 32 are rotatably mounted between the process cartridge 20 and the paper feed cassette 10.

  Above the process cartridge 20, a laser generator (not shown) that emits a laser beam, a polygon mirror (pentahedral mirror) 41 that is driven to rotate, a lens 42, a reflection mirror 43, a reflection mirror 44, a lens 45, and a reflection mirror A laser scanner unit 40 having 46 is attached. As shown in FIG. 1, the laser beam L shaken by the polygon mirror 41 is irradiated to the photosensitive drum 21 through the lens 42, the reflecting mirrors 43 and 44, the lens 45 and the reflecting mirror 46, and An electrostatic latent image is formed on the surface.

  On the left side of the process cartridge 20, a fixing unit 50 for fixing the toner on the paper is provided. The fixing unit 50 is provided with a heating roller 51 for heating and melting the toner on the transferred paper, and a pressing roller 52 disposed so as to face the heating roller 51 and pressing the fed paper toward the heating roller 51. And a pair of transport rollers 53 and 54.

In FIG. 1, a shooter 61 for reversing the direction of the sheet as necessary is attached to the left of the transport rollers 53 and 54 so as to be rotatable around a rotation shaft 62. Further, on the right side of the rotation shaft 62, a pair of paper discharges for supporting the paper transported along the shooter 61 and discharging the paper to a paper discharge tray 70 formed on the upper surface of the printer 1. Roller 64,
65 is attached.

  Next, a paper feeding operation will be described. When the paper supply roller 14 is rotated at a predetermined timing, the paper is discharged from the paper supply cassette 10 one by one. The sheet is reversed by the action of the guide 35, the position of the leading end is adjusted by the registration roller 31 and the registration roller 32, and then conveyed between the photosensitive drum 21 and the transfer roller 22.

  On the other hand, the surface of the photosensitive drum 21 charged by the charger 28 is irradiated with laser light emitted from the laser scanner unit 40 to form an electrostatic latent image. When the electrostatic latent image on the photosensitive drum 21 faces the developing roller 25, the toner conveyed through the supply roller 27 and the developing roller 25 makes the electrostatic latent image obvious, and the toner image becomes the photosensitive member. The image is transferred onto a sheet passing between the drum 21 and the transfer roller 22.

  The sheet on which the toner image is transferred next passes between the heating roller 51 and the pressing roller 52. At this time, the toner image is fixed on the sheet by applying heat and pressure to the toner image on the sheet. .

  Further, the sheet passes between the transport rollers 53 and 54 and is transported along the shooter 61, and then is discharged from the discharge rollers 63 and 64 to the discharge tray 70 with the printing surface facing down (face-down). Is done. When the shooter 61 is flipped up to the back side of the printer 1, the paper is discharged to the back side of the printer 1 with the printing surface facing up (face-up).

  FIG. 2 is a diagram illustrating a feeding mechanism of the printer 1. As shown in FIGS. 2 and 3, a motor gear 101 is attached to the output shaft of the DC motor M, the motor gear 101 meshes with the teeth 102 a of the gear 102, and the teeth 102 b of the gear 102 mesh with the teeth 103 a of the gear 103. The teeth 103b of the gear 103 mesh with the gear teeth 21a formed on the outer periphery of the photosensitive drum 21. Thus, the photosensitive drum 21 can be rotated clockwise in FIGS. 1 and 2 by rotating the motor M forward and rotating the motor gear 101 counterclockwise in FIG.

  The teeth 103a of the gear 103 are meshed with a gear 51a attached to the heat roller 51 via the pendulum gear 105 and the gear 106, whereby the driving force of the motor M is transmitted to the heat roller 51. Further, the gear 106 is engaged with the paper discharge roller 65 through a gear train (not shown). Therefore, when the motor M is rotated forward and the motor gear 101 is rotated in the counterclockwise direction, the heat roller 51 and the paper discharge roller 64 are rotated in predetermined directions indicated by arrows, respectively.

  FIG. 3 is a view showing a method for attaching the pendulum gear 105. As shown in FIG. 3, the pendulum gear 105 is attached between the main frame MF and the gear plate GP via a shaft 105a. A guide hole 105A extending in the circumferential direction of the gear 103 is formed in the gear plate GP, and a similar guide hole (not shown) is also formed in the main frame MF. Further, the pendulum gear 105 includes teeth 105 b that mesh with the teeth 103 a of the gear 103 and teeth 105 c that mesh with the teeth 106 a of the gear 106.

As shown in FIGS. 2 and 3B, the pendulum gear 105 is in contact with a friction wire 131 attached to the gear plate GP. The friction wire 131 contacts the pendulum gear 105 at a position facing the gear 103 with the shaft 105 a interposed therebetween, and causes a frictional force to act on the rotation of the pendulum gear 105. As shown in FIG. 4, the friction wire 131 is fixed using an attachment portion 132, an attachment portion 133 and a hole 134 formed on the gear plate GP, and the tip portion 131 a of the pendulum gear 10 from the main frame MF side.
5 is in contact with the vicinity of the outer peripheral end. 3 indicates the direction of the acting force that the friction wire 131 applies to the pendulum gear 105.

  When the motor M is rotated forward, the shaft 105a of the pendulum gear 105 rotates clockwise along the guide hole 105A by the force received from the gear 103 and the frictional force received from the friction wire 131, and the pendulum gear 105 The position is shown by the solid line in FIG. At this time, the teeth 105c of the pendulum gear 105 mesh with the teeth 106a of the gear 106, and the heat roller 51 and the like rotate in a predetermined direction. On the other hand, when the motor M is reversed, the shaft 105a of the pendulum gear 105 rotates counterclockwise along the guide hole 105A due to the force received from the gear 103 and the frictional force received from the friction wire 131. 105 moves to the position indicated by the chain line in FIG. As a result, the teeth 105c of the pendulum gear 105 are separated from the teeth 106 of the gear 106, and the heat roller 51 and the like can be freely rotated. Accordingly, it is possible to perform processing (jam processing) for removing paper jammed in the fixing unit 50.

  Thus, the friction wire 131 extends from the gear plate GP and contacts the pendulum gear 105 so as to hold the pendulum gear 105 from the main frame MF side. For this reason, it is possible to temporarily fix the pendulum gear 105 to the main frame side using the friction wire 131. Therefore, when assembling the feeding mechanism, the pendulum gear 105 is not likely to drop, and the assembling work is facilitated. Moreover, since the unit price of the wire used for the friction wire 131 is lower than that of the leaf spring, the cost of the apparatus can be reduced.

  In addition, the friction wire 131 is fixed using the attachment portion 132, the attachment portion 133, and the hole 134 formed in the gear plate GP, but the hole 134 is formed at a position approaching the shaft 105a of the pendulum gear 105. Therefore, the space for attaching the friction wire 131 can be gathered in a compact manner, and the entire apparatus can be reduced in size.

  On the other hand, as shown in FIG. 2, a gear 110 that meshes with the teeth 103a via gears 108 and 109 is coupled to a drive gear (not shown) of the developing cartridge 20B. The drive gear meshes with the shaft 24c, the developing roller 25, and the supply roller 27 via a gear train (not shown) provided in the developing cartridge 20B. For this reason, when the motor M is rotated forward, the shaft 24c, the developing roller 25, and the supply roller 27 rotate in predetermined directions indicated by arrows.

  Further, the gear 103 of the paper transport mechanism 120 that transmits the driving force of the motor M toward the paper feed roller 14 and the registration roller 32 meshes with the teeth 103 a of the gear 103. The paper transport mechanism 120 includes a pendulum gear 121 that meshes with the teeth 103 a of the gear 103, a gear 122 that can mesh with the pendulum gear 121, a planetary clutch 123 that meshes with the gear 122, and a planetary clutch 124 that meshes with the planetary clutch 123. With. As shown in FIG. 2, the planetary clutch 123 is engaged with a gear 32 a coaxial with the registration roller 32, and the rotation / non-rotation of the registration roller 32 is controlled by the clutch 123. A gear (not shown) provided coaxially with the paper feed roller 14 meshes with the gear 122 via the planetary clutch 124, and rotation / non-rotation of the paper feed roller 14 is controlled by the clutch 124.

FIG. 5 is a cross-sectional view showing the vicinity of the pendulum gear 121. As shown in FIGS. 2 and 5, the pendulum gear 121 is attached between the main frame MF and the gear plate GP via a shaft 121a. A guide hole 121A extending in the circumferential direction of the gear 103 is formed in the gear plate GP, and a similar guide hole (not shown) is also formed in the main frame MF. The pendulum gear 121 includes teeth 121b that mesh with the teeth 103a of the gear 103 and teeth 121c that mesh with the gear 122.

  As shown in FIGS. 2 and 5, the pendulum gear 121 is in contact with a leaf spring 141 attached to the gear plate GP. The leaf spring 141 contacts the pendulum gear 121 at a position facing the gear 103 with the shaft 121 a interposed therebetween, and causes a frictional force to act on the rotation of the pendulum gear 121.

When the motor M is rotated forward, the shaft 121a of the pendulum gear 121 rotates counterclockwise along the guide hole 121A due to the force received from the gear 103 and the frictional force received from the leaf spring 141. Is at the position indicated by the solid line in FIG. At this time, the teeth 121 c of the pendulum gear 121 are engaged with the gear 122, and the driving force of the motor M can be transmitted to the paper feed roller 14 or the registration roller 32.
On the other hand, when the motor M is rotated in the reverse direction, the shaft 121a of the pendulum gear 121 rotates clockwise along the guide hole 121A by the force received from the gear 103 and the frictional force received from the leaf spring 141. Moves to the position indicated by the chain line in FIG. As a result, the teeth 121c of the pendulum gear 121 are separated from the gear 122, and the paper feed roller 14 and the registration roller 32 can freely rotate. Therefore, it is possible to remove the paper jammed around the paper feed roller 14 and the registration roller 32 (jam processing).

  As shown in FIG. 5, a collar 121d is formed around the pendulum gear 121 so as to protrude from the tooth surface of the tooth 121b to the outer periphery. The collar 121d abuts on the outer peripheral end of the gear 103, so that the pendulum gear 121 is prevented from falling off toward the main frame MF. Moreover, since the pendulum gear 121 moves in the circumferential direction of the gear 101, the pendulum gear 121 does not move out along the guide hole 121 </ b> A so that the 121 d does not escape from the outer peripheral end of the gear 103. Therefore, it is possible to temporarily fix the pendulum gear 121 to the gear plate GP side by utilizing the engagement between the collar 121d and the gear 103. Therefore, when assembling the feeding mechanism, the pendulum gear 121 is not likely to fall, and the assembling work is facilitated.

  A pendulum gear, such as the pendulum gear 121, which is provided with a collar to prevent a drop during temporary fixing may be used for the gear train of the fixing mechanism of the printer.

Sectional drawing of the laser printer to which the pendulum gear mechanism of this Embodiment is applied. The figure which shows the paper conveyance mechanism of a laser printer. It is a figure which shows a pendulum gear, a is a figure which shows a guide hole, (b) is sectional drawing in the plane which passes along the axial center of a pendulum gear. The perspective view which shows the attachment method of a friction wire. Sectional drawing which shows the gear train of the fixing mechanism containing a pendulum gear.

103 gear (first gear)
105 pendulum gear 105a shaft 106 gear second gear 121 pendulum gear 121a shaft 121d collar 122 gear (second gear)
141 Leaf spring (friction member)
131 Friction wire (friction member)
132 Mounting part (Mounting part)
133 Mounting part (Mounting part)
134 hole (mounting part)
GP gear plate (mounting plate)

Claims (4)

With pendulum gear,
A mounting plate that movably supports the pendulum gear shaft;
A first gear that always meshes with the pendulum gear;
A second gear capable of meshing with the pendulum gear;
A friction member attached to the attachment plate, contacting the pendulum gear at a position facing the first gear across the shaft, and applying a frictional force to the pendulum gear in the rotation direction of the pendulum gear ; Prepared,
Depending on the direction of rotation of the first gear, the pendulum gear moves between a meshing position that meshes with the second gear and a disengagement position that does not mesh with the second gear;
The pendulum gear is formed with a flange protruding from its tooth surface, and the pendulum gear temporarily fixed to the mounting plate is hooked on the first gear via the collar, so that the pendulum gear falls. A pendulum gear mechanism characterized by preventing the above.   2. The pendulum gear mechanism according to claim 1, wherein the collar is formed at an end of the pendulum gear on the mounting plate side.   3. The pendulum gear mechanism according to claim 1, wherein the first gear, the pendulum gear, and the second gear constitute a gear train provided in a paper transport mechanism of a printer. 4. The pendulum gear mechanism according to claim 3, wherein the first gear, the pendulum gear, and the second gear constitute a gear train of a fixing mechanism included in a paper transport mechanism of the printer. 5.

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