JP2575107Y2 - Recording paper transport mechanism of printer using continuous recording paper - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention uses a continuous recording paper which forms an image on a continuous recording paper by using an electrophotographic method and in which a transfer charger is retracted from a transfer operation position during a printing standby. The present invention relates to a recording paper transport mechanism of a printer.

[0002]

2. Description of the Related Art Conventionally, a latent image is formed by exposing a photoreceptor on the surface of a photosensitive drum, toner is adhered to the latent image and developed, and the toner is transferred to recording paper and fixed by a fixing device. 2. Description of the Related Art An image forming apparatus using an electrophotographic method is known. One of them is an electronic printing apparatus that prints information on a foldable continuous sheet having a perforated hole called a so-called fan hold sheet which is the same as that used in a conventional line printer or the like. There is a photographic printer. The fan hold paper is configured to be cuttable with perforations at each page, and is supplied in a stacked state alternately folded in the reverse direction at the perforations.

In such a printer for forming an image on continuous recording paper, image formation must be started from a fixed position from the upper end (ie, perforation) of a page. Exposure, development,
Each of the transfer operation portions is disposed and performs each operation in accordance with the rotation of the photosensitive drum. Since the exposed portion of the photosensitive drum reaches the transfer position by the rotation of the photosensitive drum, the transfer is performed. In order to make the exposure start portion coincide with a fixed position from the perforation of the continuous paper at the start of image formation (ie, to start image formation from a fixed position from the perforation), It is necessary to relatively move (rotate) the photosensitive drum to adjust the image formation start position (so-called cueing). During this cue,
If the continuous recording paper is kept in contact with the photosensitive drum (transfer operation state), the photoconductor on the surface of the photosensitive drum is damaged or worn, thereby shortening the life of the photosensitive drum. (The toner adheres to a streak-like contact portion along the longitudinal direction of the photosensitive drum to form a so-called black streak). For this reason, the present applicant has previously configured the transfer charger so as to be able to be separated from the operation position with respect to the photosensitive drum, set the transfer charger to the operation position with respect to the photosensitive drum during image formation, and pressed the continuous recording paper against the photosensitive drum side. During standby for image formation, the transfer charger is retracted from the transfer operation position (separated from the photosensitive drum), and the pressing of the continuous recording paper against the photosensitive drum is released so that the continuous recording paper is separated from the photosensitive drum. Proposed. The retraction of the transfer charger is performed in synchronization with the stop of the conveyance of the continuous recording paper at the end of the image formation.

[0004]

However, as described above, at the end of image formation (during image formation standby), the transfer charger is separated from the photosensitive drum and the pressing of the continuous recording paper against the photosensitive drum is released. Even in this case, the continuous recording paper that has been released from being pressed against the photosensitive drum is slackened at the relevant portion, and even if the transfer charger is retracted, the continuous recording paper that is essential does not retract and continues to contact the photosensitive drum. , Becomes dirty when printing is resumed (black stripes are generated)
There was a problem.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above circumstances, and has as its object to provide a recording paper transport mechanism for a printer that uses continuous recording paper that can reliably separate the continuous recording paper from a photosensitive drum during image formation standby. And

[0006]

In order to achieve the above object, a recording paper transport mechanism of a printer using continuous recording paper according to the present invention is provided downstream of the photosensitive drum in the transport direction of the continuous recording paper.
A conveyance drive unit for conveying the continuous recording paper is provided, and the photosensitive drum is provided.
The continuous recording paper transport
A reverse drive roller driven to rotate in a direction opposite to the feeding direction;
A pressing member that sandwiches the continuous recording paper between the drive roller and
It is a thing. When the image formation is stopped, the transfer
The roller is retracted from the transfer operation position, and the reverse roller is
After the evacuation of the charger, it is configured to rotate for a predetermined time.
Have been. Thus, the reverse rotation roller is transferred to the transfer charger.
After the evacuation, the motor is driven to rotate for a predetermined time,
Continuous recording as the transfer charger retracts when image formation is stopped
Even if the paper is slack, remove the slack (by rotating the reverse rotation roller).
It can be solved by driving backward. Toes
Make sure that the continuous recording paper is loose and touches the photosensitive drum.
Can be prevented. In addition, the above pressing member is continuously
It is configured as a driven roller that can be driven and rotated in the recording paper conveyance direction.
If it is formed, continuous recording between the reverse rotation roller and the driven roller
When the recording paper tries to skew, the driven roller and continuous recording paper
Skew can be suppressed by friction with

[0007]

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 transport mechanism of a printer using continuous recording paper according to the present invention is applied. The illustrated electrophotographic printer is
This is a so-called laser beam printer, which prints or forms an image on characters or image information input from a computer or the like on fan-hold paper 20 which is continuous recording paper by electrophotography, and outputs it. Around the photosensitive drum 1, a toner cleaning unit 2, a charge removing 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, and so on. The transfer units 7 are respectively arranged in a predetermined order along the rotation direction of the drum 1, the fixing device 8 is arranged in front of the fan hold paper 20 in the transport direction, and
The tractor 9 is arranged in the transport path of the fan hold paper 20 from the printer to the fixing device 8.

As shown in an enlarged view of FIG. 2, the transfer section 7 swings the corona charger 71 at both ends thereof at a fulcrum 73 on a bracket (not shown) provided upright on the chassis 1A of the laser beam printer apparatus. Possibly pivoted arm 72
The arm 72 is oscillated and biased by a spring 75 interposed between the lower surface of the arm and the chassis 1A to hold the arm 72 in a retractable manner. The corona charger 71 is located at a predetermined position where the corona charger 71 performs a transfer operation on the photosensitive drum 1. Further, a pressing member 76 having a substantially semicircular cross section is mounted on the arm 72 on the tip side (on the side where the fan hold paper 20 is introduced) from the holding position of the corona charger 71.
When 1 is in the transfer operation position, the pressing member 76 presses the fan-hold paper 20 toward the photosensitive drum 1 so as to be in close contact with the transfer operation position. On the lower surface of the arm 72, a lever portion 72A on which a pin 77 is horizontally planted is protruded, and the operating means (not shown) moves the pin 77 toward the fan hold paper 20 discharging direction to move the arm. 72 is driven clockwise 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 FIG.

On the side of the transfer section 7 where the fan hold paper 20 is introduced, upper and lower guides 1U and 1D which are formed downward at a predetermined angle and bent upward toward the transfer section 7 on the way. The fan hold paper 20 is vertically spaced apart from each other by a predetermined distance.
The recording paper reaches the transfer section 7 through a recording paper conveyance path formed between D and D. A pair of back tension rollers 10 as tension applying means is arranged on the fan hold paper 20 introduction side of the upper and lower guides 1U and 1D. The back tension roller pair 10 includes a back tension roller 11 as a reverse drive roller that is driven to rotate in a direction opposite to the transport direction of the fan hold paper 20 by a driving unit described below under the transport path of the fan hold paper 20. In addition, a driven roller 12 as a pressing roller formed of a material having elasticity such as rubber and having a high friction coefficient is rotationally driven by a motor or the like on the upper side of the back tension roller 11 sandwiching the conveyance path of the fan hold paper 20. The fan hold paper 20 is rotatable without being pressed and arranged with a predetermined pressing force. As shown in a plan view of FIG. 5, the fan hold paper 20 has a length that covers substantially the entire area in the width direction.

The fixing device 8 is constructed by pressing a pressure roller 82 under a heat roller 81 heated by a heat source such as a halogen lamp provided therein.
The toner transferred by the transfer unit 7 to the upper surface of the fan-hold paper 20 is fused by heating and pressing the fan-hold paper 20 between the fan-hold papers 1 and 82. As a result, the heat roller 81 is driven to rotate at a peripheral speed equal to the peripheral speed of the photosensitive drum 1.
The transport of the fan hold paper 20 is performed while the fixing operation is performed by the rotation of. The tractor 9 is configured by linking a tractor belt 91 having a projection that fits into a feed hole at a side end of the fan hold paper 20 between pulleys so that its orbit coincides with the transport path of the fan hold paper 20. I have.

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 tractor 9
1 is driven by one motor 30 (driving means) as shown in FIG. 1 and a driving force transmission path from the motor 30 to the fixing device 8 and the tractor 9 is provided. A clutch 40 is provided, and when 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 on / off operation of the clutch 40. The operation of the motor 30 and the clutch 40 is controlled by the control device 50 of the laser beam printer, and the swing of the transfer unit 7 is also controlled by the control device 50 (not shown).

The control device 50 controls the operation of the motor 30, the clutch 40 and the transfer section 7, as shown in the timing chart of FIG. That is, at the start of printing preparation, the rotation of the motor 30 is started with the clutch 40 disengaged, and after a predetermined time (t1) has elapsed, printing is started simultaneously with the start of printing.
0 and the transfer unit 7 is returned to the transfer operation position. At the time of printing completion, the clutch 40 is disengaged at the same time as printing is completed, and the transfer unit 7 is retracted from the transfer operation position. After a predetermined time (t2), the rotation of the motor 30 is stopped. Stop. That is, at the start of printing preparation, first, the photosensitive drum 1 and the back tension roller 11 are driven to rotate, 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 unit 7 is transferred. When 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, and the transfer unit 7 is retracted from the transfer operation position. After a predetermined time (t2), the photosensitive drum 1 and the back tension are moved. The roller 11 is stopped.

The laser beam printer constructed as described above operates as follows. During image formation, the photosensitive drum 1 is rotated (sub-scanned) while its surface is main-scanned (exposed) in the direction of the rotation axis by a laser beam from a scanning optical system 5 to form an electrostatic latent image. The toner image is made to adhere to the developing unit 6 to form a toner image (development), and the toner image is transferred onto the fan-hold paper 20 by the transfer unit 7 and the toner image is fixed on the fan-hold paper 20 by the fixing device 8. And output. Fan hold paper 20
As described above, the fixing device 8 conveys and drives the photosensitive drum 1 at a speed equal to the peripheral speed. However, since the back tension roller 11 is rotationally driven in a direction opposite to the conveying direction of the fan hold paper 20, the back tension roller 11 is rotated. Rotates to prevent the fan hold paper 20 from being transported, and tension is applied to the fan hold paper 20 between the fixing device 8 and the back tension roller 11. The transport inhibiting force W1 of the back tension roller 11 is determined by the coefficient of dynamic friction μ of the peripheral surface of the back tension roller 11.
1 and the pressing force F by the driven roller 12 (W1 =
Here, μ1 × F) is set so that the conveyance prevention force W1 by the back tension roller 11 does not affect the conveyance speed of the fan hold paper 20. Thereby, 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 as shown in FIG.
The transfer unit 7 passes through a recording paper conveyance path formed by 1D.
The fan hold paper 20 is pushed up to the photosensitive drum 1 side by a pressing member 76 on the front side of the corona charger 71, and the upper surface thereof contacts the portion of the photosensitive drum 1 facing the corona charger 71 to perform transfer. .

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 preventing the conveyance of the fan hold paper 20 at all. For the movement of the driven roller 12 in a direction causing a slip with respect to the driven roller 12, the frictional force of the driven roller 12 acts so as to prevent the movement of the fan hold paper 20, and this acts on the back tension roller pair 10. It acts to suppress the skew of the introduced fan hold paper 20. That is, assuming that the coefficient of static friction 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 given by W2 = μ1 × F + μ2 × F. By changing the coefficient of static friction μ2 of the peripheral surface of the roller 12, the movement inhibiting force W <b> 2 of the fan hold paper 20 in the direction in which the driven roller 12 slips without changing the transport inhibiting force W <b> 1 of the fan hold paper 20. Can be changed. That is, in the present embodiment, the fact that the transport speed of the fan hold paper 20 is reduced to a predetermined value or less due to the transport inhibiting force W1 of the back tension roller pair 10 means that the fixing device 8 that transports the fan hold paper 20 is driven. This is not preferable because the slippage occurs between the heat roller 81 and the fan-hold paper 20, which causes a disturbance in the fixed image, and the conveyance stopping force W <b> 1 does not affect the conveyance speed of the fan-hold paper 20. Although there is an upper limit due to the fact that the driven roller 12 has to be set, the transport inhibiting force W
The force W2 for preventing movement of the fan-hold paper 20 in the direction in which it slides on the driven roller 12 without increasing
Can be increased.

At the end of printing, first, simultaneously with the end of printing, the driving of the fixing device 8 and the tractor 9 is stopped, and the transfer section 7 is retracted from the transfer operation position. Since the pressing of the fan hold paper 20 against the photosensitive drum 1 by the transfer unit 7 is released by the retreat of the transfer unit 7, the fan hold paper 20 is slackened, but at this time, the back tension still in the driving state is still being driven. The roller 11 is transported by the slack in the direction opposite to the introduction direction, and the slack is eliminated as shown in FIG.
And separate. The transport path of the fan hold paper 20 is as follows.
It goes without saying that the transfer section 7 is set to be in a path that does not come into contact with the photosensitive drum 1 by applying tension in the retracted state (by eliminating slackness).

With the above-described configuration, when the transfer section 7 is retracted from the transfer operation position in the printing standby state, the looseness of the fan-hold paper 20 is eliminated, so that the photosensitive drum 1
As a result, the contact portion of the fan hold paper 20 becomes dirty (black streaks occur) when the photosensitive drum 1 idles (at the time of cueing) at the start of printing. That is not something. In the above embodiment, the back tension roller pair 10 is configured to have a length extending over the entire width of the fan hold paper 20. However, the present invention is not limited to this. The roller member may be arranged intermittently and can be changed as appropriate. In addition, static electricity may be generated because the back tension roller 11 and the fan hold paper 20 are rubbed during printing.
This can be avoided by forming the first roller or the driven roller 12 with a conductive member and also making the member holding the roller conductive, and connecting it to the chassis (earth) of the laser beam printer.

[0017]

As described above, according to the recording paper transport 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 during the standby for printing. It is possible to prevent the photosensitive drum from being kept in contact with the drum and to prevent dirt on the photosensitive drum from adhering to the continuous recording paper during cueing when printing is resumed. Further, the tension applying means has a configuration in which a pressing roller is disposed in pressure contact with a reverse driving roller which is driven to rotate in a direction opposite to the direction of transport of the continuous recording paper, so that the frictional force of the reverse driving roller applies tension to the continuous recording paper. And the skew can be suppressed by preventing the continuous recording paper from moving in the direction of causing slippage with respect to the pressing roller by the frictional force of the pressing roller,
By increasing the frictional force of the pressing roller, it is possible to increase the force for preventing the continuous recording paper from moving in the direction in which the pressing roller slides without increasing the tension on the continuous recording paper.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a laser beam printer to which a recording paper transport 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 unit and a reverse drive roller.

FIG. 3 is a view showing a state in which a transfer unit is retracted from FIG. 2;

FIG. 4 is a timing chart showing retraction of a transfer unit and operation control of a reverse drive roller.

FIG. 5 is a conceptual configuration diagram equivalent 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 drive means) 10 ... Back tension roller pair (tension provision means) 11 ... Back tension roller (reverse drive roller) 12 ... Follower roller (pressing roller) 20 ... Fan hold Paper (continuous recording paper) 71 Corona charger (transfer charger)

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Taizo Saito 2-36-9 Maeno-cho, Itabashi-ku, Tokyo Asahi Optical Industry Co., Ltd. (56) References JP-A-1-306268 (JP, A) JP-A JP-A-3-26571 (JP, A) JP-A-2-69275 (JP, A) JP-A-62-88764 (JP, A) JP-A-3-200981 (JP, A) JP-A-62-70947 (JP, A) , U) Japanese Utility Model Hei 2-95652 (JP, U) Japanese Utility Model 50-22728 (JP, Y1) (58) Fields investigated (Int. Cl. ⁶ , DB name) B41J 15/04-15/16 G03G 15/00 510-534 G03G 21/00 370-540

Claims (3)

(57) [Scope of request for utility model registration] An image is recorded on a continuous recording paper using electrophotography.
A printer for forming a photosensitive drum , the photosensitive drum being opposed to the photosensitive drum, and being connected to the photosensitive drum .
And a transfer charger for performing a transfer operation on the continuous recording paper.
In the printer, downstream of the photosensitive drum in the direction of conveyance of the continuous recording paper,
A transport drive unit for transporting the continuous recording paper is provided, and on the upstream side in the transport direction of the continuous recording paper from the photosensitive drum,
Reverse drive that rotates in the direction opposite to the direction of continuous recording paper transport
The continuous recording paper is sandwiched between the roller and the reverse driving roller.
And a pressing member disposed in pressure contact with the transfer charger.
And the reverse roller is further moved after the transfer charger is retracted.
Uses continuous recording paper characterized in that it is driven to rotate for a fixed time.
Printer paper transport mechanism. 2. The pressing member according to claim 1, wherein said pressing member moves in a conveying direction of the continuous recording paper.
A driven roller that can be driven and rotated.
A recording paper transport of a printer using the continuous recording paper according to claim 1.
Sending mechanism. 3. The peripheral surface of the driven roller is formed by an elastic member.
The continuous recording according to claim 2, wherein the recording is performed.
A recording paper transport mechanism for printers that use paper.