JPH0516327U - Recording paper transport mechanism of printer using continuous recording paper - Google Patents

Abstract

(57) [Abstract] [Purpose] A recording paper conveyance mechanism for a printer that uses continuous recording paper that can be reliably separated from the photosensitive drum during standby for image formation. [Structure] A back tension roller 11 that is driven to rotate in the conveyance direction of the fan hold paper 20 on the side of the photosensitive drum 1 on which the fan hold paper 20 is introduced, and an upper side of the back tension roller 11 that sandwiches the conveyance path of the fan hold paper 20. A back tension roller pair 10 configured by a rotatable driven roller 12 arranged in pressure contact is arranged.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention is a recording paper conveyance mechanism for a printer using continuous recording paper, which is configured to form an image on continuous recording paper by using electrophotography and which is configured so that the transfer charger is retracted from the transfer operation position while waiting for printing. Regarding

[0002]

[Prior Art]

 Conventionally, a so-called electrophotographic method in which a photoreceptor on the surface of a photosensitive drum is exposed to form a latent image, a toner is attached to the latent image for development, toner is transferred to recording paper, and is fixed by a fixing device An image forming apparatus that uses a printer is known, and one of them is an electronic photograph that prints information on folding continuous paper with a feed hole called so-called fan hold paper that is used in conventional line printers. There is a printer. The fan-hold paper is designed so that it can be cut at the perforations at each page as perforations, and is supplied in a laminated state in which the perforations are alternately folded in opposite directions.

In such a printer that forms an image on continuous recording paper, it is necessary to start image formation from a fixed position from the upper end of the page (that is, perforations). Exposure, development, and transfer action sections are arranged around the drum to perform various actions in accordance with the rotation of the photosensitive drum. The exposed section of the photosensitive drum is moved to the transfer position by the rotation of the photosensitive drum. Since the transfer is performed up to now, it is necessary to match the exposure start portion to a fixed position from the perforation of the continuous paper at the start of image formation (that is, to start image formation from the constant position from the perforation). Before the image formation starts, it is necessary to move (rotate) the photosensitive drum relative to the continuous paper to adjust the image formation start position (so-called cueing). If the continuous recording paper remains in contact with the photosensitive drum (transfer operation state) at the time of this cueing, the photosensitive member on the surface of the photosensitive drum will be scratched or worn and the life of the photosensitive drum will be shortened. However, there is a problem that the continuous paper is soiled by the residual toner (toner adheres to the streak-shaped contact portion along the longitudinal direction of the photosensitive drum to generate a so-called black streak). For this reason, the applicant previously configured the transfer charger so that it can be separated from the position where it acts on the photosensitive drum, and during image formation, the transfer charger is placed in the position where it acts on the photosensitive drum and the continuous recording paper is pressed against the photosensitive drum. The transfer charger is retracted from the transfer operation position (separated from the photosensitive drum) during standby for image formation, and the continuous recording paper is released from the photosensitive drum by pressing the continuous recording paper against the photosensitive drum. Suggested things. The transfer charger is retracted in synchronism with the stop of the continuous recording paper conveyance at the end of image formation.

[0004]

[Problems to be solved by the device]

 However, even if the transfer charger separates from the photosensitive drum and the continuous recording paper is not pressed against the photosensitive drum at the time of completion of image formation (during image formation standby) as described above, The continuous recording paper released from pressing is loosened at the area, and even if the transfer charger retracts, the essential continuous recording paper does not retract but keeps contacting with the photosensitive drum, and as a result, becomes dirty when printing is restarted. There was the problem of (creating black streaks).

[0005]

[The purpose of the device]

 The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a recording paper feeding mechanism of a printer that can continuously separate the continuous recording paper from the photosensitive drum during standby for image formation.

[0006]

[Means for solving the problem]

 In order to achieve the above object, the recording paper transport mechanism of the printer using the continuous recording paper according to the present invention forms an image on the continuous recording paper by using the electrophotographic method. In the downstream side of the transport direction of the continuous recording paper, the continuous recording paper transport drive means is provided, and the transfer charger is configured to retreat from the transfer operation position while waiting for image formation. On the upstream side in the carrying direction, a tension applying means for applying a force to the continuous recording paper in a direction opposite to the carrying direction is provided. Further, the tension applying means is arranged in reverse contact with the reverse drive roller which is rotationally driven in the direction opposite to the continuous recording paper conveying direction, and is arranged in pressure contact with the reverse drive roller sandwiching the continuous recording paper, and is driven to rotate in the continuous recording paper conveying direction. And a possible pressing roller.

[0007]

[Example of device]

 Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of an electrophotographic printer to which an embodiment of a recording paper conveying mechanism of a printer using continuous recording paper according to the present invention is applied. The illustrated electrophotographic printer is a so-called laser beam printer, and prints or forms an image of character or image information input from a computer or the like on a fan-hold paper 20 which is a continuous recording paper by an electrophotographic method and outputs it. It is a thing. Around the photosensitive drum 1, a toner cleaning unit 2, a charge eliminating unit 3, a charging unit 4, a scanning optical system 5 for guiding a laser beam onto the photosensitive drum 1, a developing unit 6. The transfer portions 7 are arranged in a predetermined order along the rotation direction of the drum 1, and the fixing device 8 is arranged in front of the fan-hold paper 20 in the conveying direction, and the fan from the photosensitive drum 1 to the fixing device 8 is arranged. The tractor 9 is arranged in the conveyance path of the hold paper 20.

As shown in an enlarged view of FIG. 2, the transfer unit 7 has a corona charger 71 at both ends thereof, which is supported at a fulcrum 73 on a bracket (not shown) standing on the chassis 1A of the laser beam printer. The arm 72 is swingably supported so as to be parallel to and retractable from the photosensitive drum 1. The arm 72 is interposed between the lower surface of the arm 72 and the chassis 1A. The corona charger 71 held by the spring 75 is oscillated and urged so that the corona charger 71 is at a predetermined position where the corona charger 71 transfers to the photosensitive drum 1. Further, a pressing member 76 having a substantially semicircular cross section is mounted on the tip side of the arm 72 from the holding position of the corona charger 71 (on the side where the fan hold paper 20 is introduced), and the corona charger 71 is at the transfer operation position. At this time, the pressing member 76 presses the fan hold paper 20 toward the photosensitive drum 1 to bring it into close contact with the transfer operation position. On the lower surface of the arm 72, a lever portion 72A in which a pin 77 is horizontally planted is projected, and by operating an operating means (not shown) in the discharge direction side of the fan hold paper 20, a lever portion 72A is operated. The arm 72 is oscillated in the clockwise direction in the figure against the urging force of the spring 75, and the corona charger 71 is retracted downward from the transfer operation position in the figure as shown in the third figure.

On the introduction side of the fan hold paper 20 from the transfer section 7, the introduction side is formed downward at a predetermined angle and is bent upward toward the transfer section 7 midway. , 1D are vertically separated from each other by a predetermined distance, and the fan hold paper 20 reaches the transfer portion 7 through a recording paper conveyance path formed between the upper and lower guides 1U, 1D. .. A back tension roller pair 10 as a tension applying means is arranged further on the fan hold paper 20 introduction side than the upper and lower guides 1U and 1D. The back tension roller pair 10 is provided with a back tension roller 11 as a reverse driving roller which is rotationally driven in a direction opposite to the conveying direction of the fan hold paper 20 by a driving unit described below under the conveying path of the fan hold paper 20. In addition, the driven roller 12 as a pressing roller formed of a material having elasticity such as rubber and having a high friction coefficient is sandwiched by the back tension roller 11 on the upper side of the conveyance path of the fan hold paper 20 and is rotated by a motor or the like. It is configured so that it can be rotated without being driven, and is arranged in pressure contact with a predetermined pressing force. As shown in the plan view of FIG. 5, the fan hold paper 20 has a length over substantially the entire width direction.

The fixing device 8 is constituted by disposing a pressure roller 82 under pressure on a heat roller 81 heated by a heat source such as a halogen lamp provided therein, and a fan hold between both rollers 81 and 82. By sandwiching the paper 20 and heating and pressing it, the toner transferred by the transfer unit 7 is fused to the upper surface of the fan-hold paper 20, and the heat roller 81 is provided around the photosensitive drum 1 by a driving means described later. The heat roller 81 is driven to rotate at a peripheral speed equal to the rotation speed, and the fan roller 20 is conveyed while the fixing operation is performed by the rotation of the heat roller 81. The tractor 9 is constructed by linking a tractor belt 91 having a projection fitted into a feed hole at a side end of the fan hold paper 20 with its orbital track aligned with the conveyance path of the fan hold paper 20 and linking between the pulleys. There is.

Here, the rotation of the photosensitive drum 1, the rotation of the back tension roller 11 of the back tension roller pair 10, the rotation of the heat roller 81 of the fixing device 8, and the rotation of the tractor belt 91 of the tractor 9 are as shown in FIG. It is driven by one motor 30 (driving means), and a clutch 40 is provided in a driving force transmission path from the motor 30 to the fixing device 8 and the tractor 9. While the motor 30 is being driven, the drive control can be performed independently of the photosensitive drum 1 and the back tension roller 11 by the intermittent operation of the clutch 40. The operation of the motor 30 and the clutch 40 is controlled by the controller 50 of the laser beam printer, and the swinging of the transfer section 7 is also controlled by the controller 50 (not shown).

The control device 50 controls the operation of the motor 30, the clutch 40 and the transfer portion 7, as shown in the timing chart of FIG. That is, at the start of printing preparation, the rotational driving of the motor 30 is started with the clutch 40 disengaged, and after a lapse of a predetermined time (t1), the clutch 40 is connected simultaneously with the start of printing, and the transfer portion 7 is moved to the transfer operation position. When the printing is completed and the printing is completed, the clutch 40 is cut at the same time as the printing is completed, the transfer unit 7 is retracted from the transfer operation position, and the rotation of the motor 30 is stopped after a predetermined time (t2). That is, at the start of printing preparation, first, the photosensitive drum 1 and the back tension roller 11 are rotationally driven, the fixing device 8 and the tractor 9 are driven in synchronization with the start of printing after a predetermined time (t1), and the transfer portion 7 is moved. When the printing is completed and the printing is completed, the driving of the fixing device 8 and the tractor 9 is stopped at the same time as the printing is completed, the transfer section 7 is retracted from the transfer application position, and the photosensitive drum 1 is removed after a predetermined time (t 2). The back tension roller 11 is stopped.

The laser beam printer device configured as described above operates as follows. During image formation, while the photosensitive drum 1 is rotationally driven (sub-scanning), its surface is main-scanned (exposed) in the rotational axis direction by the laser beam from the scanning optical system 5 to form an electrostatic latent image. Toner is attached to the image in the developing unit 6 to form a toner image (development), the toner image is transferred onto the fan-hold paper 20 by the transfer unit 7, and the toner image is transferred onto the fan-hold paper 20 by the fixing device 8. Is fixed and output. The fan hold paper 20 is conveyed and driven by the fixing device 8 at a speed equal to the peripheral speed of the photosensitive drum 1 as described above, but the back tension roller 11 is rotationally driven in a direction opposite to the conveying direction of the fan hold paper 20. Therefore, the rotation of the back tension roller 11 acts so as to prevent the fan hold paper 20 from being conveyed, and tension is applied to the fan hold paper 20 between the fixing device 8 and the back tension roller 11. The conveyance blocking force W1 by the back tension roller 11 depends on the dynamic friction coefficient μ1 of the peripheral surface of the back tension roller 11 and the pressing force F by the driven roller 12 (W1 = μ1 × F). The conveyance blocking force W1 by 11 is set to a force that does not affect the conveyance speed of the fan hold paper 20. As a result, an appropriate tension (back tension) is applied to the fan hold paper 20 between the fixing device 8 and the back tension roller 11, and the recording paper conveyance formed by the upper and lower guides 1U and 1D as shown in FIG. The fan hold paper 20 reaching the transfer unit 7 through the path is pushed up to the photosensitive drum 1 side by the pressing member 76 on the front side of the corona charger 71, and the upper surface of the fan hold paper 20 faces the corona charger 71. And the transfer is performed.

Here, since the driven roller 12 of the back tension roller pair 10 rotates following the conveyance of the fan-hold paper 20, it does not contribute to the prevention of the conveyance of the fan-hold paper 20, but the fan-hold paper 20 does not. With respect to the movement of the driven roller 12 in the direction in which the driven roller 12 slips, the frictional force of the driven roller 12 acts so as to prevent the movement of the fan holder paper 20, which causes the back tension roller pair 1 to move. It acts so as to suppress the skew of the fan-hold paper 20 introduced to 0. Immediately, assuming that the static friction coefficient of the peripheral surface of the driven roller 12 is μ2, the force (holding force) W2 for preventing the movement of the fan hold paper 20 is W2 = μ1 × F + μ2 × F. By changing the static friction coefficient μ2 of the peripheral surface of the driven roller 12, the fan hold paper 20 is moved in the direction in which it slides with respect to the driven roller 12 without changing the conveyance blocking force W1 of the fan hold paper 20. The blocking force W2 can be changed. That is, in the present embodiment, the conveyance blocking force W1 of the back tension roller pair 10 reduces the conveyance speed of the fan hold paper 20 below a predetermined value, which means that the fixing device 8 that conveys and drives the fan hold paper 20. This is not preferable because it causes slippage between the heat roller 81 and the fan-hold paper 20 and disturbs the fixed image, and the conveyance blocking force W1 does not affect the conveyance speed of the fan-hold paper 20. Since there is an upper limit from the fact that the driven roller 12 has a large static friction coefficient μ2 on its peripheral surface, the driven roller 12 of the fan hold paper 20 can be applied to the driven roller 12 without increasing the conveyance inhibiting force W1. On the other hand, the movement preventing force W2 in the direction of causing slippage can be increased.

Upon completion of printing, first, the driving of the fixing device 8 and the tractor 9 is stopped at the same time as the completion of printing, and the transfer unit 7 is retracted from the transfer operation position. The retracting of the transfer unit 7 releases the pressing of the fan-hold paper 20 on the photosensitive drum 1 by the transfer unit 7, so that the fan-hold paper 20 is loosened, but at this time, it is still in the drive state. The tension roller 11 conveys only the slack in the direction opposite to the introduction direction, and the slack is eliminated as shown in FIG. It is needless to say that the transfer path of the fan hold paper 20 is set so that the transfer section 7 does not come into contact with the photosensitive drum 1 by applying tension in the retracted state (by eliminating slack). Nor.

With the above-described configuration, when the transfer unit 7 is retracted from the transfer operation position during the print standby, the slack of the fan hold paper 20 is eliminated, and thus the contact state with the photosensitive drum 1 is maintained. As a result, when the photosensitive drum 1 idles at the start of printing (at the time of cueing), the contact portion of the fan-hold paper 20 becomes dirty (black streaks occur), which does not cause a problem. In the above embodiment, the back tension roller pair 10 has a length extending over the entire width of the fan hold paper 20, but the present invention is not limited to this. The roller members may be arranged intermittently and can be changed appropriately. Further, static electricity may be generated due to rubbing between the back tension roller 11 and the fan hold paper 20 during printing, but the back tension roller 11 or the driven roller 12 is formed of a conductive member and the member holding the roller is also conductive. This can be avoided by connecting to the chassis (ground) of the laser beam printer.

[0017]

[Effect of the device]

 As described above, according to the recording paper feeding mechanism of the printer using the continuous recording paper according to the present invention, the continuous recording paper is reliably retracted and separated from the photosensitive drum to contact the photosensitive drum during printing standby. Continuation can be prevented, and stains on the photosensitive drum can be prevented from adhering to the continuous recording paper at the time of cueing when printing is resumed. In addition, the tension applying means is configured such that the pressing roller is arranged in pressure contact with the reverse driving roller that is rotationally driven in the direction opposite to the conveying direction of the continuous recording paper, so that the friction force of the reverse driving roller causes the tension to be applied to the continuous recording paper. In addition, it is possible to prevent the skew by suppressing the movement of the continuous recording paper in the direction in which it slides with respect to the pressing roller due to the frictional force of the pressing roller. By increasing the frictional force of the pressing roller, the continuous recording paper can be prevented. It is possible to increase the force for preventing the continuous recording paper from moving in the direction in which it slides with respect to the pressure roller without increasing the tension on the pressure roller.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a laser beam printer to which a recording paper conveyance mechanism structure of a printer using continuous recording paper according to the present invention is applied.

FIG. 2 is a partially enlarged view of a transfer portion and a reverse drive roller portion.

FIG. 3 is a diagram showing a state in which a transfer unit is retracted from FIG.

FIG. 4 is a timing chart showing the retracting of the transfer portion and the operation control of the reverse driving roller.

FIG. 5 is a conceptual configuration diagram corresponding to a plan view of a reverse drive roller portion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Photosensitive drum 7 ... Transfer part 8 ... Fixing device (conveyance driving means) 10 ... Back tension roller pair (tension applying means) 11 ... Back tension roller (reverse driving roller) 12 ... Followed roller (pressing roller) 20 ... Fan hold Paper (continuous recording paper) 71 ... Corona charger (transfer charger)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Taizo Saito 2-6-9 Maenocho, Itabashi-ku, Tokyo Asahi Gaku Gakuin Kogyo

Claims (4)

[Scope of utility model registration request] 1. An image is formed on a continuous recording sheet by using an electrophotographic method, and a conveying driving means for the continuous recording sheet is provided downstream of a photosensitive drum in a conveying direction of the continuous recording sheet. In a configuration in which the transfer charger retreats from the transfer operation position during standby for image formation, a force in a direction opposite to the transport direction is applied to the continuous recording paper upstream of the photosensitive drum in the transport direction of the continuous recording paper. A recording paper conveying mechanism for a printer using continuous recording paper, characterized in that it is provided with a tension applying means for acting. 2. The tension applying means is arranged such that a reverse drive roller that is rotationally driven in a direction opposite to the direction in which the continuous recording paper is conveyed, and a reverse drive roller that is arranged in pressure contact with the continuous recording paper sandwiched between the reverse driving roller and the reverse drive roller. 2. A recording paper conveyance mechanism for a printer using continuous recording paper according to claim 1, wherein the recording paper conveyance mechanism comprises a pressing roller capable of being driven and rotated in a direction. 3. A recording paper feeding mechanism for a printer using continuous recording paper according to claim 2, wherein the pressing roller is formed by an elastic member with a peripheral surface thereof having a predetermined frictional force. 4. A recording paper conveying mechanism for a printer using continuous recording paper according to claim 2, wherein the reverse drive roller is configured to operate for a predetermined time after the transfer charger is retracted. ..