KR20060024237A - Feeding apparatus of duplex printer - Google Patents

Abstract

The conveying apparatus of the disclosed duplexer includes a printing path in which paper fed from a paper cassette is printed, a duplex conveying path for conveying paper from the duplex roller to the printing path during duplex printing, and a duplex conveying path installed on the duplex conveying path to print the paper. And a power transmission unit which transfers power to the duplex transfer unit to transfer the duplex transfer unit and the driving member so that the duplex transfer unit transfers the paper only in a predetermined direction.

According to the present invention, unlike the conventional conveying apparatus, by using only one driving source to convey the paper, the structure is simplified, and the number of parts can be reduced.

Description

Feeding apparatus of duplex printer

1 is a cross-sectional view schematically showing a conventional duplexer.

2 is a cross-sectional view schematically showing a duplexer according to a preferred embodiment of the present invention.

3 is a perspective view showing a transfer device of the duplexer.

4 is a perspective view of the transfer device of the double-sided printing machine in FIG.

5 is a view for showing the power transmission to the duplex roller of the transfer device shown in FIG.

6 is a view showing a power transmission unit for transmitting power to the duplex transfer unit of the transfer apparatus shown in FIG.

7 is a view showing the operation of the guide member.

<Description of the symbols for the main parts of the drawings>

100 ... pick-up rollers 110, 190 ... feeding rollers

115 ... paper-aligner 120 ... photoreceptor

125 ... Transfer 130                 

140 ... decal 145 ... guide member

C ..... Printing Path D ..... Duplex Feed Path

200 ... Drive 202, 204 ... Drive member

235.Duplex roller 250.Power train

252 ... 3rd driven gear 254 ... 1st driven gear

256 ... 2nd driven gear 270, 290 ... Duplex transfer section

270 ... 1st feed section 272 ... 1st directional rotatable driven gear

274 2nd directional rotatable driven gear 280 belt

290 ... 2nd transfer part K ..... duplexer feeder

The present invention relates to a duplexer, and more particularly to a transfer device of the duplexer.

In recent years, the spread of the Duplex printer which can print on both sides of printing paper is expanding. The duplexer operates by printing on one side of the paper first, then changing the orientation of the paper and printing on the other side again. Therefore, the duplexer needs a separate transfer path for transferring the once-printed paper back to the printing path. The part within the press forming this path is called the duplex transfer path.

1 is a cross-sectional view schematically showing a conventional duplexer.

Referring to Fig. 1, a conventional duplexer includes a paper feed cassette (not shown), feeding rollers 10 and 90, a registration roller 15, a developing device (not shown), and a photosensitive member 20. ), Transfer unit 25, fixing unit 30, decal unit 40, duplex roller 50, duplex transfer unit 61, 62, 63, 64, 65 and two drive sources 45 60).

The optical scanning unit (not shown) scans the light corresponding to the image information to the photoconductor 20 to be described later according to a computer signal so that an electrostatic latent image is formed on the outer circumferential surface of the photoconductor 20. The optical scanning unit (not shown) includes a light source (not shown) for scanning a laser beam, and a beam deflector (not shown) for deflecting the laser beam irradiated from the light source.

The developing apparatus (not shown) is in the form of a cartridge, and has a housing (not shown) that forms an exterior, a developing roller (not shown), a toner layer regulating portion (not shown), a supply roller (not shown), and an agitator therein. , Not shown) is installed. Also, a toner storage unit (not shown) for accommodating toner as a developer is provided inside the housing (not shown). The developing apparatus (not shown) is replaced with a new one when all the toner contained in the toner storage unit (not shown) is used up.

The developing roller (not shown) attaches the toner contained in the housing (not shown) to its outer circumference and supplies the toner to the photosensitive member 20. A developing roller (not shown) contains toner in the form of a solid powder, and these toners are supplied to an electrostatic latent image formed on the photosensitive member 20 to develop a toner image. A developing bias voltage for supplying these toners to the photosensitive member 20 is applied to a developing roller (not shown).                         

A developing gap of a predetermined interval may be maintained between the photosensitive member 20 and a developing roller (not shown). The force from the photosensitive member 20 to the developing roller (not shown) is generated by the electric field, and the charged toner is transferred while vibrating and reciprocating in the developing region formed between the developing gaps.

The supply roller (not shown) supplies the toner so that the toner is attached to the developing roller (not shown). An agitator (not shown) swings the toner at a predetermined speed so that the toner in the toner storage unit (not shown) is not hardened, and transfers the toner toward the supply roller (not shown).

The toner layer regulating unit (not shown) is fixed at one side to the housing (not shown) and the other side is in contact with the developing roller (not shown) to regulate the height of the toner adhered to the outer circumferential surface of the developing roller, and toner to a predetermined polarity. Triboelectrically charged.

The photoconductor 20 coated with the photoconductive material layer by a deposition method or the like on the outer circumferential surface of the cylindrical metal drum is rotated in a predetermined direction, and is installed such that a part of the outer circumferential surface is exposed. The photosensitive member 20 is charged to a predetermined potential by a charging roller (not shown), and an electrostatic latent image corresponding to an image to be printed by light irradiated from a light scanning unit (not shown) according to the computer signal as described above. This is formed on the outer circumferential surface thereof. The outer circumferential surface exposed to the outer circumference of the photoconductor 20 faces the transfer part 25.

A charging bias voltage is applied to a charging roller (not shown) in order to charge the outer circumference of the photosensitive member 20 to a uniform electric potential.

The transfer section 25 is provided so as to face the outer circumferential surface of the photosensitive member 20, and a transfer bias voltage having a polarity opposite to that of the toner image is applied so that the toner image developed on the photosensitive member 20 is transferred to the paper. The toner image is transferred to the paper by the electrostatic force acting between the photosensitive member 20 and the transfer section 25. The toner image developed on the outer circumferential surface of the photosensitive member 20 may be transferred to a sheet passing between the transfer portion 25 and the photosensitive member 20 by the contact pressure between the photosensitive member 20 and the transfer portion 25.

The fixing unit 30 includes a heat roller 32 and a pressure roller 34 installed to face the heat roller 32, and fixes the toner image to the paper by applying heat and pressure to the toner image transferred to the paper. The heat roller 32 is provided to be opposed to the pressure roller 34 in the axial direction as a heat source for permanently fixing the toner image. The pressure roller 34 is installed to face the heat roller 32 so as to apply a high pressure to the paper to fix the toner image on the paper.

The decal part 40 removes the curl of the paper in which the curl was generated by the heat while passing through the fixing part 30.

The duplex roller 50 rotates in both directions in association with the first driving source 45 to discharge the paper conveyed along the printing path A or to convey the paper transferred to the duplex conveying path B. FIG. That is, in the single-sided printing, the duplex roller 50 discharges the paper conveyed along the printing path A, and in the case of the double-sided printing, the duplex roller 50 rotates in reverse to transfer the paper to the duplex conveying path B. FIG.

The duplex transfer unit 61, 62, 63, 64, 65 operated in conjunction with the second drive source 60 are installed on the duplex transfer path B to transfer the paper transferred from the duplex roller 50 to the printing path A. Transfer to.

The duplexer also includes a paper feed cassette (not shown) on which paper is loaded. The pickup roller 5 is provided above the paper cassette and picks up the sheets loaded in the paper cassette and picks them out one by one.

The feeding rollers 10 and 90 provide a conveying force for conveying the picked sheet and the sheet conveyed along the duplex conveying path B to the sheet sorter 15 side. The registration roller 15 aligns the paper so that the toner image can be transferred to a desired portion of the paper before the paper passes between the photosensitive member 20 and the transfer unit 25.

Hereinafter, look at the operation and operation of the conventional duplexer and the duplexer transfer device.

The photosensitive member 20 is charged at a uniform potential by a charging bias voltage applied to a charging roller (not shown). The optical scanning unit (not shown) irradiates the photosensitive member 20 with light corresponding to the image information. When light is scanned, only the scanned portion is selectively discharged to lower the potential, and the output pattern formed by the potential difference is an electrostatic latent image.

On the other hand, the toner inside the toner storage unit (not shown) is stirred by a stirrer (not shown), and is supplied to a developing roller (not shown) to which a developing bias voltage is applied by a supply roller (not shown). The toner adhered to the outer circumference of the developing roller (not shown) is thinned to a uniform thickness by a toner layer restricting portion (not shown). At this time, the toner is charged while being rubbed by the developing roller (not shown) and the toner layer regulating unit (not shown). The toner adhered to the outer circumference of the developing roller (not shown) is attached to a peak latent image formed on the outer circumference of the photoconductor 20, and the toner image is developed on the photoconductor 120.

In the single-sided printing, the paper is taken out from the paper feed cassette (not shown) by the pickup roller 5. The paper is conveyed by the feeding roller 10, fed and aligned by the paper sorter 15, and passes between the photosensitive member 20 and the transfer unit 25. At this time, when a transfer bias voltage is applied to the transfer section 25, the toner image formed on the photosensitive member 20 is transferred to the paper. Toner remaining on the outer circumferential surface of the photoconductor 20 after transfer is removed by a cleaning member (not shown) and accumulated in the waste toner storage unit (not shown). The fixing unit 30 applies heat and pressure to the toner image formed on the paper after transfer to fix the toner image on the paper. The decal unit 40 removes curl from the paper on which curl is generated when passing through the fixing unit 30. The paper passing through the decal unit 40 is discharged out of the duplexer via the duplex roller 50 and loaded on the discharge tray (not shown). In the single-sided printing as described above, the paper is discharged through a printing path (A) and the duplex roller 50 to the discharge stage (not shown).

In the duplex printing, the paper is transferred to the duplex roller 50 via the printing path A in the single-side printing as described above. After the rear end of the paper is conveyed to the duplex roller 50, the duplex roller 50 rotates in the reverse direction and conveys the paper to the duplex feed path (B). The paper conveyed along the duplex feed path B is fed by the duplex feed units 61, 62, 63, 64, 65 and the feeding roller 90, fed and aligned by the paper sorter 15, and duplex printing. Proceeds. The paper conveyed along the printing path A is discharged to a discharge bin (not shown) via the duplex roller 50.

As described above, according to the related art, since two driving sources 45 and 60 are installed, two motors are required, which causes more noise and requires more space. In addition, as a plurality of rollers are required for the duplex transfer portions 61, 62, 63, 64, 65, the weight of the transfer apparatus increases, and the number of parts of the drive portion increases.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems described above, and an object thereof is to provide a transfer device of a duplex printing press with a simple driving method and structure.

According to the present invention, a double-sided printing device is a conveying apparatus comprising: a printing path for printing paper fed from a paper cassette; A duplex roller for conveying the sheet having passed through the printing path; A duplex transfer path for transferring the paper from the duplex roller to the printing path when duplex printing; A drive member for transmitting power in association with a drive source rotating in both directions; A duplex transfer unit installed on the duplex transfer path to transfer the paper to the printing path; A power transmission unit interlocked with the driving member and transmitting power to the duplex transfer unit so that the duplex transfer unit transfers the paper only in a predetermined direction; It is characterized by including.

The duplex roller may be rotated in both directions so as to transfer the paper conveyed along the printing path in conjunction with the driving member to the discharge and the duplex conveying path.

The duplex transfer unit is connected to the driving source and transfers the paper conveyed from the duplex roller along the duplex transfer path, the first transfer unit having a rotary shaft and a roller coupled thereto; A second conveying part which conveys the paper conveyed from the first conveying part toward the printing path; And a first one-way rotary driven gear and a second one-way rotary driven gear which are in contact with the power transmission unit to transfer the driving force transmitted from the driving member to the rotary shaft in one direction only. It is preferably installed coaxially, the first transfer portion and the second transfer portion is preferably linked to the belt coupling.

The power transmission unit includes a plurality of driven gears interlocked with the driving member, wherein the driven gears mesh with the first driven gear and the second general rotating driven gear that mesh with the first one-way rotary driven gear. And a second driven gear, wherein the first driven gear and the second driven gear each have a driving force in a different rotational direction so that the first feeder transfers the paper only in one direction regardless of the rotational direction of the drive member. It is characterized in that the transfer to the one-way rotary driven gear and the second one-way rotary driven gear.

The conveying apparatus of the duplex printer guides the paper passing through the printing path to the duplex roller, and selectively transfers the paper so that the paper is conveyed from the duplex roller to the duplex conveying path during duplex printing. It is preferable to further include a guide member for guiding.

Hereinafter, with reference to the accompanying drawings looks at with respect to the transfer device of the duplexer according to a preferred embodiment of the present invention and the duplexer to which it is applied.

2 is a cross-sectional view schematically showing a double-sided printer according to a preferred embodiment of the present invention, Figure 3 is a perspective view showing a portion K shown in Figure 2, Figure 4 is a perspective view of only the transport device in FIG. 5 is a view showing a power transmission to the duplex roller of the transfer device shown in Figure 4, Figure 6 is a view showing a power transfer unit for transmitting power to the duplex transfer unit of the transfer device shown in FIG. 7 is a view showing the operation of the guide member.

Referring to the drawings, the duplexer according to a preferred embodiment of the present invention, a paper feed cassette (not shown), feeding rollers (110, 190), a paper sorter (Registration roller, 115), a developing device (not shown) And the photosensitive member 120, the transfer unit 125, the fixing unit 130, the decal unit 140, the guide member 145, the duplex roller 235, and the duplex transfer unit 270, 290. It is provided.

The optical scanning unit (not shown) scans the light corresponding to the image information to the photoconductor 120 to be described later in accordance with a computer signal to form an electrostatic latent image on the outer circumferential surface of the photoconductor 120. The optical scanning unit (not shown) includes a light source (not shown) for scanning a laser beam, and a beam deflector (not shown) for deflecting the laser beam irradiated from the light source.

The developing apparatus (not shown) is in the form of a cartridge, and has a housing (not shown) that forms an exterior, a developing roller (not shown), a toner layer regulating portion (not shown), a supply roller (not shown), and an agitator therein. , Not shown) is installed. Also, a toner storage unit (not shown) for accommodating toner as a developer is provided inside the housing (not shown). The developing apparatus (not shown) is replaced with a new one when all the toner contained in the toner storage unit (not shown) is used up.

The developing roller (not shown) attaches the toner contained in the housing (not shown) to its outer circumference and supplies the toner to the photosensitive member 120. A developing roller (not shown) contains toner in the form of a solid powder, and supplies these toners to an electrostatic latent image formed on the photosensitive member 120 to develop the toner image. A developing bias voltage for supplying these toners to the photosensitive member 120 is applied to a developing roller (not shown).                     

A developing gap of a predetermined interval may be maintained between the photosensitive member 120 and a developing roller (not shown). The force from the photosensitive member 120 to the developing roller (not shown) is generated by the electric field, and the charged toner is transferred while vibrating and reciprocating in the developing region formed between the developing gaps.

The supply roller (not shown) supplies the toner so that the toner is attached to the developing roller (not shown). An agitator (not shown) swings the toner at a predetermined speed so that the toner in the toner storage unit (not shown) is not hardened, and transfers the toner toward the supply roller (not shown).

The toner layer regulating unit (not shown) is fixed at one side to the housing (not shown) and the other side is in contact with the developing roller (not shown) to regulate the height of the toner adhered to the outer circumferential surface of the developing roller, and toner to a predetermined polarity. Triboelectrically charged. As the toner layer regulating portion, it is preferable to use a metal plate having elastic force.

The photoconductor 120 coated with the photoconductive material layer by a deposition method or the like on the outer circumferential surface of the cylindrical metal drum is rotated in a predetermined direction, and is installed such that a part of the outer circumferential surface is exposed. The photosensitive member 120 is charged to a predetermined potential by a charging roller (not shown), and an electrostatic latent image corresponding to an image to be printed by light irradiated from a light scanning unit (not shown) according to a computer signal as described above. This is formed on the outer circumferential surface thereof. The outer circumferential surface exposed to the outer circumference of the photosensitive member 120 faces the transfer part 125.

A charging bias voltage is applied to a charging roller (not shown) in order to charge the outer circumference of the photosensitive member 120 to a uniform potential. Instead of a charging roller (not shown), a corona discharger (not shown) may be employed.                     

The transfer unit 125 is provided to face the outer circumferential surface of the photosensitive member 120, and a transfer bias voltage having a polarity opposite to that of the toner image is applied so that the developed toner image is transferred to the paper. The toner image is transferred to the paper by the electrostatic force acting between the photosensitive member 120 and the transfer part 125. The toner image developed on the outer circumferential surface of the photoconductor 120 may be transferred to a sheet passing between the transfer unit 125 and the photoconductor 120 by the contact pressure between the photoconductor 120 and the transfer unit 125.

The fixing unit 130 includes a heat roller 132 and a pressure roller 134 installed to face the heat roller 132, and fixes the toner image to the paper by applying heat and pressure to the toner image transferred to the paper. The heat roller 132 is installed to be axially opposed to the pressure roller 134 as a heat source for permanently fixing the toner image. The pressure roller 134 is installed to face the heat roller 132 to apply a high pressure to the paper to fix the toner image on the paper.

The decal unit 140 removes curl of paper from which curl is generated by heat while passing through the fixing unit 130.

The guide member 145 is installed on the guide shaft 147 to guide the paper passing through the printing path C to the duplex roller 235, and the duplex transfer path D from the duplex roller 235 during duplex printing. The paper feed path is selectively guided to feed the paper. The guide member 145 guides the transport path of the paper while operating to approach or space the print path C.

The duplex roller 235 rotates in both directions in conjunction with the driving members 202 and 204 to be described later to discharge or transfer the paper conveyed along the printing path C to the duplex conveying path D. That is, in the single-sided printing, the duplex roller 235 discharges the paper conveyed along the printing path (C), and in the double-sided printing, the duplex roller transfers the paper passing through the guide member 145 in the duplex transfer path (D). Transfer to.

The duplex transfer units 270 and 290 are installed on the duplex transfer path D to transfer the paper transferred from the duplex roller 235 to the printing path C.

The duplexer also includes a paper feed cassette (not shown) on which paper is loaded. The pickup roller 100 is provided above the paper cassette and picks up one sheet of paper loaded in the paper cassette.

The feeding rollers 110 and 190 provide a conveying force for conveying the picked sheet and the sheet conveyed along the duplex feed path D to the sheet sorter 115 side. The registration roller 115 aligns the paper so that the toner image can be transferred to a desired portion of the paper before the paper passes between the photosensitive member 120 and the transfer unit 125.

Hereinafter, with reference to Figures 3 and 4, looks at in detail the configuration of the transfer device (K) of the double-sided printing press.

Referring to the drawings, the transfer device (K) of the double-sided printer is a printing path (C), duplex roller 235, duplex transfer path (D), drive members (202, 204), power transmission unit 250 ) And duplex transfer portions 270 and 290.

The printing path (C) is a path through which paper fed from a paper cassette (not shown) is printed, and the duplex transfer path (D) is a path through which paper is fed from the duplex roller 235 to the printing path (C) during duplex printing. .                     

The driving members 202 and 204 operate in conjunction with the driving source 200 which rotates in both directions to transmit power to the duplex roller 235 and the power transmission unit 250. In this embodiment, the driving member includes a first driving member 202 that receives power from the driving source 200, and a second driving member 204 that transmits power to the duplex roller 235 and the power transmission unit 250. Equipped. The first driving member 202 and the second driving member 204 are coaxially rotated in the same direction and transmit power to the duplex roller 235 and the power transmission unit 250.

Referring to FIG. 5, the second driving member 204 is installed to be linked with the driving source 200 to transmit the driving force transmitted from the driving source 200 to the first idle gear 210. The second idler gear 212 is installed on the coaxial 214 with the first idler gear 210, and transfers a sheet of paper by transmitting a driving force to the driving roller 213 installed on the coaxial 214. At the position facing the driving roller 213, a shaft 215 is provided in parallel with the shaft 214, and the paper is conveyed along the printing path C therebetween.

The driving force transmitted to the first idle gear 210 is transmitted to the duplex gear 230 through a plurality of idle gears 220 and 225 sliding with the second idle gear 212 installed in the coaxial 214.

The duplex roller 235 transfers the paper to the discharge or duplex transfer path D using the driving force transmitted from the duplex gear 230 installed in the coaxial 232 as described above. In the position opposite to the duplex roller 235 is provided with an idle roller 240 for sliding with a predetermined pressure on the duplex roller 235.

Referring to FIG. 4, the duplex transfer units 270 and 290 include a first transfer unit 270 and a second transfer unit 290. The first transfer unit 270 is interlocked with the driving source 200, and transfers the paper transferred from the duplex roller 235 along the duplex transfer path D. The first transfer unit 270 includes a rotation shaft 275 and a roller 276 coupled thereto. At one side thereof, the first and second one-way rotary driven gears 272 and 274 which transmit the driving force transmitted from the driving members 202 and 204 to the rotation shaft 275 in one direction only by sliding with the power transmission unit 250 are provided. It is provided coaxially with the rotating shaft 275. The first and second one-way rotatable driven gears 272 and 274 transmit the driving force only in the direction in which the paper is conveyed along the duplex transfer path D to the printing path C, and the driving force in the opposite direction. Install to idle without transmission.

The second transfer part 290 has a rotating shaft 292 and the rollers 294 coupled thereto. The second transfer unit 290 is installed in parallel with the first transfer unit 270 to transfer the paper transferred from the first transfer unit 270 to the printing path C along the duplex transfer path D. The first and second transfer parts 270 and 290 are coupled to the belt 280 at the pulleys 277 and 295 provided at one side thereof. As described above, the second transfer unit 290 receives the driving force from the first transfer unit 270 through the belt 280 to transfer the paper along the duplex transfer path D in the same direction as the first transfer unit 270. do.

Referring to FIG. 6, the power transmission unit 250 includes a plurality of driven gears 252, 254, and 256 that cooperate with the driving members 202 and 204. The third driven gear 252 is arranged to be engaged with the second idle gear 212 receiving power from the second driving member 204. The first driven gear 254 is engaged with the third driven gear 252 to receive a driving force, and is arranged to be engaged with the second driven gear 256 and the first one-way rotary driven gear 272 at the same time. The second driven gear 256 is meshed with the first driven gear 254 to receive a driving force, so that the second driven gear 256 is engaged with only the second one-way rotary driven gear 274 without being engaged with the first one-way rotary driven gear 272. Is placed. That is, the first one-way rotary driven gear 272 is disposed to mate with the first driven gear 254, and the second one-way rotary driven gear 274 is disposed to mate with the second driven gear 256. In the above configuration, the first driven gear 254 and the second driven gear 256 respectively transmit driving forces in different directions to the first transfer part 270, and the first and second installed in the first transfer part 270. Since the one-way rotatable driven gears 272 and 274 transmit power only in one direction, the first transfer part 270 rotates only in one direction regardless of the rotation direction of the driving source 200 and transfers paper. In the present embodiment, the case of three driven gears has been described as an example, but the present invention is not limited thereto and various modifications can be made.

Hereinafter, look at the operation and operation of the duplexer and the duplexer conveying apparatus according to a preferred embodiment of the present invention.

The photosensitive member 120 is charged at a uniform potential by a charging bias voltage applied to a charging roller (not shown). The optical scanning unit (not shown) irradiates the photoreceptor 120 with light corresponding to the image information. When light is scanned, only the scanned portion is selectively discharged to lower the potential, and the output pattern formed by the potential difference is an electrostatic latent image.

On the other hand, the toner inside the toner storage unit (not shown) is stirred by a stirrer (not shown), and is supplied to a developing roller (not shown) to which a developing bias voltage is applied by a supply roller (not shown). The toner adhered to the outer circumference of the developing roller (not shown) is thinned to a uniform thickness by a toner layer restricting portion (not shown). At this time, the toner is charged while being rubbed by the developing roller (not shown) and the toner layer regulating unit (not shown). The toner attached to the outer circumference of the developing roller (not shown) is attached to a peak latent image formed on the outer circumference of the photoconductor 120, and the toner image is developed on the photoconductor 120.

In single-sided printing, the paper is taken out from the paper feed cassette (not shown) by the pickup roller 100. The paper is conveyed by the feeding roller 110, fed and aligned by the paper sorter 115, and passes between the photosensitive member 120 and the transfer unit 125. At this time, when the transfer bias voltage is applied to the transfer unit 125, the toner image formed on the photosensitive member 120 is transferred to the paper. Toner remaining on the outer circumferential surface of the photoconductor 120 after transfer is removed by a cleaning member (not shown) and accumulated in the waste toner storage unit (not shown). The fixing unit 130 applies heat and pressure to the toner image formed on the paper after transfer to fix the toner image on the paper. The decal unit 140 removes curl from the paper on which the curl is generated when passing through the fixing unit 130. The paper passing through the decal unit 140 is discharged out of the duplexer through the duplex roller 235 and is loaded on the discharge tray (not shown). As described above, in the case of single-sided printing, the paper is discharged through a printing path C and the duplex roller 235 through a discharge tray (not shown).

In duplex printing, the paper is transferred to the duplex roller 235 via the printing path C at the time of single-side printing as described above. After the rear end of the paper is transferred to the duplex roller 235 via the guide member 145, the duplex roller 235 rotates in the reverse direction and conveys the paper to the duplex feed path (D). At this time, as shown in Figure 7, the guide member 145 is rotated in a direction close to the printing path (C) so that the paper is transferred to the duplex transfer path (D). The paper conveyed along the duplex feed path (D) is conveyed by the first conveying unit 270, the second conveying unit 290, and the feeding roller 190, and is fed and aligned by the paper sorter 115 to print on both sides. Proceeds. The paper conveyed along the printing path C passes through the original guide member 145 and is discharged through a duplex roller 235 to a discharge table (not shown).

Hereinafter will be described in detail the operation of the transfer device (K) of the duplex printer.

For description of the operation, the rotation direction of the duplex roller 235 is clockwise (CW) when the paper is fed from the duplex roller 235 to the duplex feed path D in the direction of the duplex roller 235. ) And the opposite direction is referred to as counterclockwise (CCW).

First, the paper is transported to the duplex roller 235 via the printing path (C). Referring to FIG. 5, the first driving member 202 receives the driving force from the driving source 200 and rotates in the counterclockwise direction (CCW). The second driving member 204 coaxially provided with the first driving member 202 also rotates in a counterclockwise direction (CCW), transmits a driving force to the first idle gear 210, and the first idle gear 210 is clockwise. Rotate in the direction CW. The second idler gear 212, which is provided coaxially with the first idler gear 210, also rotates clockwise (CW) and transmits a driving force to the driving roller 213 installed on the coaxial 214 to transfer the paper to the duplex roller 235. ) To the side. The idle gear 220 sliding with the second idler roller 212 rotates in a counterclockwise direction (CCW) and transmits the driving force to another idle gear 225 engaged with the driving force. The idle gear 225 rotates clockwise (CW) and transmits a driving force to the duplex gear 230. The duplex gear 230 receives the driving force from the idle gear 225 and rotates in a counterclockwise direction (CCW), that is, the paper is conveyed to the duplex roller 235 side through the printing path (C). When the paper is transported in the duplex transfer path D, the driving source 200 is reversed to transmit power to the first driving member 202.

In this case, the operation of the power transmission unit 250 and the duplex transfer units 270 and 290 will be described.

First, the paper is transported to the duplex roller 235 via the printing path (C).

Referring to FIG. 6, the first driving member 202 receives the driving force from the driving source 200 and rotates in the counterclockwise direction (CCW). The second driving member 204 coaxially provided with the first driving member 202 also rotates in a counterclockwise direction (CCW) and transmits a driving force to the first idle gear 210, and the first idle gear 210 is clockwise. Rotate in the direction CW. The second idler gear 212 provided coaxially with the first idler gear 210 also rotates in a clockwise direction CW. Since the third driven gear 252 is operated by meshing with the second idle gear 212, the third driven gear 252 rotates in the counterclockwise direction CCW. Since the first driven gear 254 is engaged with the third driven gear 252 to receive the driving force, the first driven gear 254 rotates in the clockwise direction CW. Since the driving force is transmitted by being engaged with the first unidirectional rotatable driven gear 272 and the first driven gear 254, the rotation is counterclockwise (CCW). At this time, since the first one-way rotary driven gear 272 transmits only a driving force in one direction, that is, clockwise (CW), the first one-way rotary driven gear 272 is idling to the first driven gear 254. The driving force transmitted by the above may not be transmitted to the first transfer unit 270. Since the second driven gear 256 meshes with the first driven gear 254 to receive the driving force, the second driven gear 256 rotates in the counterclockwise direction (CCW). Since the driving force is transmitted by being engaged with the second one-way rotary driven gear 274 and the second driven gear 256, it rotates in the clockwise direction CW. At this time, since the second one-way rotary driven gear 274 transmits only the driving force in one direction, that is, the clockwise direction CW, the driving force transmitted by the second driven gear 256 is transmitted to the first transfer unit 270. The second transfer part 290 coupled to the first transfer part 270 also rotates in a clockwise direction CW to transfer paper.

Let's look at the case where the driving source 200 is reversed to transfer the driving force.

The first driving member 202 receives the driving force from the driving source 200 and rotates in the clockwise direction CW. The second driving member 204 coaxially provided with the first driving member 202 also rotates in a clockwise direction CW and transmits a driving force to the first idle gear 210, and the first idle gear 210 is counterclockwise. Rotate in the direction CCW. The second idler gear 212 provided coaxially with the first idler gear 210 also rotates in a counterclockwise direction (CCW). Since the third driven gear 252 is operated by being engaged with the second idle gear 212, the third driven gear 252 rotates in the clockwise direction CW. Since the first driven gear 254 is engaged with the third driven gear 252 to receive the driving force, the first driven gear 254 rotates in the counterclockwise direction (CCW). Since the driving force is transmitted by being engaged with the first one-way rotary driven gear 272 and the first driven gear 254, it rotates in a clockwise direction CW. At this time, since the first one-way rotary driven gear 272 transmits only the driving force in one direction, that is, clockwise CW, the driving force transmitted by the first driven gear 254 is transmitted to the first transfer part 270. Since the second driven gear 256 is engaged with the first driven gear 254 to receive the driving force, the second driven gear 256 rotates in the clockwise direction CW. Since the driving force is transmitted by being engaged with the second one-way rotary driven gear 274 and the second driven gear 256, it rotates in a counterclockwise direction (CCW). At this time, since the second one-way rotary driven gear 274 transmits only the driving force in one direction, that is, clockwise (CW), the second one-way rotary driven gear 274 is idling to the second driven gear 256. The driving force transmitted by the above may not be transmitted to the first transfer unit 270.

That is, the duplex transfer units 270 and 290 are driven by the second one-way rotary driven gear 274 at the forward rotation of the drive source 200, and the first one-way rotary driven gear 272 at the reverse rotation of the drive source 200. Since only the driving force in the clockwise direction CW is transmitted, the paper transfers the paper only in one direction regardless of whether the driving source 200 is driven reversely.

According to the configuration as described above, the present invention can drive the printing path (C) and the duplex transfer path (D) with a single drive source 200, unlike the prior invention, the duplex transfer unit (270, 290) belt coupling As a result, the number of power transmission parts such as a roller installed in the duplex transfer path D can be reduced.

As described above, the transfer apparatus of the duplexer according to the present invention is simple in structure by transporting the paper using only one drive source, unlike the conventional invention using two drive sources, it is possible to reduce the number of parts. Since the driving source is reduced to one, the trouble caused by this is reduced, thereby simplifying maintenance.

In addition, by transmitting power to the duplex transfer unit using a belt, the number of power transmission parts can be reduced, and the number of assembly and space is easily facilitated, thereby improving productivity.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and those skilled in the art to which the art belongs can make various modifications and other equivalent embodiments therefrom. Will understand. Therefore, the true technical protection scope of the present invention will be defined by the claims below.

Claims (5)

Transfer of a duplex printer having a printing path in which paper fed from a paper cassette is printed, a duplex roller for conveying the paper passing through the printing path, and a duplex feed path for transporting the paper from the duplex roller to the printing path. In the apparatus, A drive member for transmitting power in association with a drive source rotating in both directions; A duplex transfer unit installed on the duplex transfer path to transfer the paper to the printing path; A power transmission unit interlocked with the driving member and transmitting power to the duplex transfer unit so that the duplex transfer unit transfers the paper only in a predetermined direction; Transfer device of the double-sided printing machine characterized in that it comprises. The method of claim 1, And the duplex roller rotates in both directions to transfer the paper conveyed along the printing path to the discharge medium and the duplex conveying path in association with the driving member. The method of claim 2, The duplex transfer unit, A first conveying unit having a rotating shaft and a roller coupled thereto to transfer the paper conveyed from the duplex roller in association with the driving source along the duplex conveying path; A second conveying part which conveys the paper conveyed from the first conveying part toward the printing path; Equipped, The first transfer part is provided with a first one-way rotary driven gear and a second one-way rotary driven gear coaxially with the rotary shaft, which are in contact with the power transmission unit to transfer the driving force transmitted from the driving member to the rotary shaft only in one direction. , The first conveying unit and the second conveying unit is a conveying apparatus of the double-sided printer, characterized in that interlocked by the belt coupling. The method of claim 3, The power transmission unit includes a plurality of driven gears interlocked with the driving member, wherein the driven gears mesh with the first driven gear and the second general rotating driven gear that mesh with the first one-way rotary driven gear. A second driven gear, Regardless of the rotational direction of the drive member, the first driven gear and the second driven gear each have a driving force in a different rotational direction so as to transfer the paper only in one direction. Transfer device of the double-sided printing machine, characterized in that the transfer to match the one-way rotary driven gear. The method according to any one of claims 1 to 4, And a guide member for guiding the paper passing through the printing path to the duplex roller, and selectively guiding the conveying direction of the paper so that the paper is transferred from the duplex roller to the duplex feed path during duplex printing. Transfer device of the double-sided printer, characterized in that.

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