JP3027411B2 - Paper ejection device of image forming apparatus - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a facsimile, and a printer.

[Conventional technology]

In an image forming apparatus such as a laser printer, a document,
There is a demand for stapling or filing the recording paper that has been discharged onto the paper discharge section where an image such as a diagram is formed, and there is a demand for aligning the recording paper that has been discharged. It is necessary to improve the stackability, which is precision.

However, in a conventional apparatus of this type, the recording paper discharged and stacked in the paper discharge unit is perpendicular to the recording paper transport direction due to a variation in the parallelism and mechanical characteristics of the paper feeding and transport mechanism and each unit. Shift occurred in the horizontal direction, which is an unfavorable direction, and sufficient stackability was not obtained.

Factors that reduce this stackability include, for example,
The following are mentioned.

(1) Deviation of the recording paper in the mechanical device The widthwise guide in the paper cassette is set to be slightly wider than the standard width of the recording paper in consideration of the cutting variation of the recording paper. Depending on where the recording paper is placed in the width direction in the cassette, the recording paper is offset in the recording apparatus.

For example, the recording paper is shifted during conveyance due to variations in the outer shape accuracy, the pressing force of both side ends, the positional accuracy, the parallelism, and the like of the conveyance roller pair in the conveyance mechanism in the recording apparatus.

The magnitude of the curl of the recording paper causes a magnitude of resistance due to friction with the members constituting the transport path, and the recording paper is shifted.

(2) Deterioration of stackability when paper is discharged from the paper device to the paper discharge unit.

Since the recording paper discharged from the paper discharging device falls onto the mounting table of the paper discharging unit and is placed thereon, there is no restriction on the recording paper at the time of falling, and the mounting position varies due to air resistance or the like.

Among these factors, regarding the above factor (1), it is known that in a double-sided printing in which images are formed on both the front and back sides of a recording sheet, a jogger is provided on a double-sided mounting portion to correct the printing position on the front and back sides. However, in this case, it is necessary to provide a jogger, which has led to an increase in complexity of the apparatus and an increase in cost. Regarding the factor (2), it is known that an operation-type tray is provided in the paper discharge unit. However, if the deviation of the recording paper in the mechanical device before the paper discharge unit is not suppressed, It is not a complete measure.

[Problems to be solved by the invention]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the related art, and has as its object the simple configuration of correcting the horizontal direction of recording paper at the stage of discharging to a paper discharge unit. It is an object of the present invention to provide an image forming apparatus capable of performing such operations.

[Means for solving the problem]

In order to achieve the above object, the invention according to claim 1 includes a paper feeding means for feeding a recording sheet via a conveyance path to a recording section provided with an optical system unit and a latent image carrier, and a discharging section from the recording section. An image forming apparatus having a paper discharging device for transporting recording paper to a paper section, wherein a transporting member of the transporting device for applying a transport force to the recording paper is moved in a direction perpendicular to the recording paper transporting direction during the recording paper discharging operation. Moving means for moving; moving amount setting means for setting a moving amount by the moving means; adjusting means for adjusting a horizontal latent image forming position on the latent image carrier by the optical system unit; And an adjustment amount setting means for setting an adjustment amount according to (1), wherein the movement amount is set according to the adjustment amount.

According to a second aspect of the present invention, there is provided a sheet feeding means for feeding a recording sheet to a recording section having an optical system unit and a latent image carrier via a conveyance path, and conveying the recording sheet from the recording section to a discharge section. And forming an image by conveying one surface of the recording paper to the recording unit to form an image, and then conveying the back surface of the one surface of the recording paper to the recording unit to form an image Thus, in an image forming apparatus for forming an image on both the front and back sides of a recording sheet, a conveying member of the conveying apparatus for applying a conveying force to the recording sheet during a recording sheet discharging operation after the image is formed on the rear side Moving means for moving in a direction perpendicular to the conveying direction; moving amount setting means for setting a moving amount by the moving means; and a lateral direction on the latent image carrier by the optical system unit for forming an image on the back surface. Adjusting means for adjusting the latent image forming position of the image forming apparatus, and adjusting means for setting an adjustment amount by the adjusting means. Adjusting amount setting means, wherein the moving amount is set according to the adjusting amount.

[Action]

The lateral shift of the recording paper in the image forming apparatus is unique to each apparatus, and the direction and the amount of the shift are substantially constant.

On the other hand, if the conveying member is moved in a direction perpendicular to the recording and conveying direction during the recording sheet discharging operation, the horizontal position of the recording sheet discharged to the discharging section can be changed.

Therefore, the moving amount is set by the moving amount setting means so that the recording paper is discharged to a predetermined position of the paper discharging unit while canceling the direction and the amount of the deviation, and this setting is performed during the recording paper discharging operation. The conveying member is moved in a direction perpendicular to the recording paper conveying direction by the moving means in accordance with the moving amount, thereby acting to discharge the recording paper to a predetermined position of the paper discharge section.

〔Example〕

An embodiment in which the present invention is applied to a laser printer as an image forming apparatus will be described.

FIG. 1 is a diagram showing a schematic configuration of a laser printer having a plurality of paper feeding and conveying mechanisms.

A printer body 1 of the laser printer includes an optical system unit 3 for optically operating a photosensitive drum 2 as a latent image carrier, a developing device 4, a photosensitive drum 2, a cleaning device 5, a transfer separation charger 6, and the like. A process unit 7 for performing a recording process, including:
The image forming apparatus includes a paper cassette 8 and a second paper cassette 9, and a fixing unit 10 for fixing the toner image on the recording paper developed by the process unit 7 by applying heat and pressure.
Further, as a paper discharge unit for receiving the recorded recording paper, the first paper discharge tray 11 and the second paper discharge tray 12 are provided on the upper part of the printer main body 1, and are fixed to the left side of the printer main body 1 so as to be swingable. A third paper discharge tray 13 that can be stored during use is provided.

Further, the printer main body 1 turns over a separate large-volume paper feed unit 14 used as necessary as a so-called option and a recording paper recorded on one side of the fixing unit 10 and supplies it to the process unit 7 again. Reversing unit for 15
It is mounted on an optional unit comprising:

The first paper feed cassette 8, the second paper feed cassette 9, and the large-volume paper feed unit 14 are provided with paper feed rollers 16, 17, and 18, respectively, for sequentially sending out recording paper. A registration roller 19 and a registration sensor 20 for positioning the recording paper and the image to be recorded in the recording paper feed direction are provided in front of the registration roller 19. Above the base of each of the first paper discharge tray 11, the second paper discharge tray 12, and the third paper discharge tray 13, a first paper discharge roller pair 21 and a second paper discharge roller pair for discharging recording paper are respectively provided. 22, a third discharge roller pair 23 are provided, and the first discharge roller pair 21 and the second
The movement of the discharge roller pair 22 in the axial direction is controlled by a movement control mechanism, which is a moving means described later. Fixing unit
The recording paper exiting 10 is transferred to a first discharge tray 11 and a second discharge tray.
12, a first switching claw 24 for switching to which of the third discharge tray 13 and the reversing unit 15 the sheet is conveyed, and which of the first discharge tray 11 and the second discharge tray 12 A second switching claw 25 for switching whether to convey the recording paper is provided. In the conveyance path from the first switching claw 24 to the second switching claw 25, a first conveyance roller pair 26 and a lower discharge sensor 27 are provided.
Is provided, and a second discharge roller pair from the second switching claw 25 is provided.
A second conveyance roller pair 28 and an upper sheet discharge sensor 29 are provided in the conveyance path extending to 22.

The reversing unit 15 switches the transport path between receiving the recording paper conveyed from the printer main body 1 and sending out the received recording paper toward the registration rollers 19 of the printer main body 1. A switching claw 30 is provided, and a reversing portion entrance sensor 3 is provided near the third switching claw 30.
1. A reversing section exit sensor 32 and a table exit sensor 33 are provided in a transport path from the third switching claw 30 to the registration roller 19 of the printer body 1.

Each of the above sensors detects the leading edge or the trailing edge of the recording paper in the transport path, and detects a jam based on whether the recording paper reaches or passes the sensor position within a predetermined time, and displays a jam as necessary. The lower sheet ejection sensor 27 and the upper sheet ejection sensor 29 are provided with a first
It is also used to control the movement of the discharge roller pair 21 and the second discharge roller pair 22.

FIG. 2 is a diagram showing a configuration of the optical system unit 3 in FIG. The optical system unit 3 includes a laser diode 40 for emitting laser light, a collimator lens 41 for condensing the laser light to narrow the spot, a cylindrical lens 42, and a polygon mirror for optically scanning with a polygonal rotating mirror. 43, an Fθ lens 44 for correcting the direction of the laser beam so that the scanning of the light spot on the photoconductor is linear, a mirror 45 for changing the direction of the laser beam to a position below the photoconductor, and the beginning of each scanning cycle Synchronous detection sensor for detecting
46, an optical housing 47 for housing these optical members in a light-shielded manner.

The outline of the operation of the laser printer shown in FIG. 2 will be described. This laser printer converts a character code or the like sent from a host device such as a computer or a word processor into a video signal of a dot pattern corresponding to the character code by a controller (character generator), and an engine driver of the printer body. Each control unit is controlled to perform recording. Recording papers are stacked and set in the first and second paper feed cassettes 8 and 9 and the large-volume paper feed unit 14, respectively. These paper cassettes 8, 9 or paper feed rollers 16,
One of 17, 18 is selectively driven according to the paper start command, the recording paper is sent out, and the leading end of the
When the recording paper reaches the registration rollers 19, the recording paper is pressed against the registration rollers 19, the skew of paper feeding is forced, and the paper feeding rollers 16, 17, or 18 are temporarily stopped.
After correcting the skew, the paper feed rollers 16, 17, or 18 are driven again, and the registration rollers 19 are also driven, and the recording paper is sent to the transfer section of the process unit 7.

As described above, the recording paper fed from the first and second paper feeding cassettes 8 and 9, the large-volume paper feeding unit 14 or the reversing unit 1515 is moved at the registration roller 19 in the recording paper feeding direction, that is, the sub-scanning direction. By adjusting the timing of feeding the paper from the registration roller 19 to the photoconductor, the relative positional relationship between the image on the photoconductor and the recording paper is adjusted.

On the other hand, generally no automatic adjustment means is provided in the horizontal direction of the recording paper, that is, in the main scanning direction. However, a lateral shift occurs while the recording paper is conveyed from the paper cassettes 8 and 9 and the large-volume paper supply unit 14 to the registration rollers 19.

In addition, when passing through the reversing unit 15, the deviation becomes large. When recording on one side of the recording paper and then recording on the other side, the recording paper exiting the fixing unit 10 is sent to the reversing unit 15 and after being reversed, reaches the registration roller 19 again and reaches again. I do. Since the transport path for the reversal is long, the recording paper may be shifted in the horizontal direction while being transported along the transport path.

The horizontal deviation of these paper feeds is caused by paper feed cassettes 8, 9,
It differs depending on the inclination of each unit of the large-volume sheet feeding unit 14 and the reversing unit 15 and the mechanism. Such a shift in the lateral direction changes the relative positional relationship between the photosensitive member and the recording paper, and the recorded image is recorded on the recording paper with a deviation. The deviation is unique to each machine,
Adjustments must be made precisely for each machine. Generally, such adjustment for each machine is performed by precisely performing mechanical adjustment of the transport path. But,
The adjustment work is time and labor consuming. In this embodiment, since the relative positional relationship between the image on the photosensitive member and the recording paper is adjusted by an electric operation as described later, the adjustment operation can be performed relatively easily.

Next, in the optical system unit 3, the on-cuff light emission of the laser diode 40 is controlled by a video signal synchronized with the control timing sent from the controller. The emitted laser beam passes through the lenses 41 and 42 and is incident on the polygon mirror 43 rotating counterclockwise. The reflected laser beam changes the reflection direction with the rotation of the polygon mirror 43 while changing the reflection direction. Go through 44. The passed laser beam arrives while moving from one end A to the other end B of the beam redirection mirror 45 and is reflected downward.

A charged photosensitive member of the process unit 7 is disposed below the beam direction changing mirror 45, and the irradiated laser beam forms a latent image on the photosensitive member depending on whether or not the photosensitive member is charged.

The formed latent image is developed by the developing device 4 of the process unit 7, transferred to a recording sheet, and fixed by the fixing unit 10 to perform recording.

When the first discharge tray 11 or the second discharge tray 12 is selected as the discharge tray, the recording paper discharged from the fixing unit 10 is guided to the upward conveying path by the first switching claw 24. Then, the sheet is further discharged to a selected one of the first and second discharge trays 11 and 12 by the second switching claw 25. When the third discharge tray 13 is selected as the discharge tray, the first switching claw 24 guides the third discharge tray 13 straight to the third discharge tray 13 and discharges the paper to the third discharge tray 13. The paper discharge to the third paper discharge tray 13 is a relatively straight conveyance path, and thus is suitable for a case where an envelope or the like in which curls or wrinkles easily occur is used as recording paper.

Next, a lateral registration adjusting device of the laser printer device in this example will be described.

Normally, in a laser printer, as shown in FIG. 2, a laser beam is scanned by a polygon mirror 43 and provided at a specific position in the optical system unit 3 corresponding to a position before a writing start position of an image on a photoconductor. Synchronous detection sensor
The scanning laser beam is detected by 46, and the detection output is used as a synchronization detection signal in the main scanning direction. As shown in FIG. 3, a signal Z indicating the writing start position of the image is generated at a fixed time after the generation of the synchronization detection signal, and then a signal W indicating the writing end position at a certain time determined by the size of the recording paper. appear.

In this example, the generation point of the signal Z indicating the writing start position of the image is adjusted according to the shift of the horizontal registration position, and the relative positional relationship between the image on the photoconductor and the recording paper is adjusted.

 FIG. 4 is a block diagram of an electrical unit for that purpose.

In FIG. 1, a dip switch 50 is a switch for setting a writing start position of an image common to the first and second sheet cassettes 8 and 9, a dip switch 51 is a switch for setting an image writing start position of the mass feeding unit 14, The dip switch 52 is a switch for setting an image writing start position on a recording sheet passing through the reversing unit 15. These dip switches are, for example, four-digit binary numbers as shown in FIG.
This dip switch is connected to a first discharge roller pair (to be described later).
It is also directly connected to the main body control unit 53 for controlling the movement of the pair 21 and the second discharge roller pair 22.

The multiplexer 54 is provided with a selection signal from the main body control unit 53 including the CPU, I / O, memory, etc.
Selection signal indicating which of 8, 9, 14, and 15 is selected)
Thus, one of the dip switches 50, 51, 52 is selected and connected to a preset (programmable) counter 55.

The preset counter 55 is reset every time a synchronization detection signal is generated, and an initial value for counting an image writing start position is preset by the contents of the dip switches 50, 51, and 52, and becomes a reference for image writing from that point. The image clock WCLK (WRITE CLOK) is counted and output to the decoder 56.

The decoder 56 decodes a specific value of the output of the preset counter 55 and outputs the writing start position signal Z and the image writing end position signal W of FIG.

The main body control unit 53 is a control device that includes a CPU, an I / O, a memory, etc., captures image data in synchronization with an image clock WCLK in response to a print request from a controller, and controls the entire printer. .

The control device 57 such as a motor is a control device that executes the operation of each unit of the printer device in accordance with an instruction from the main body control unit 53.

The controller 58 is located between the host device 59 and the printer device, and converts information such as an ASCII code sent from the host device 59 into character pattern image data and sends it to the printer.

 Next, the operation of writing position adjustment will be described.

Cassettes 8 and 9, high-volume paper feed unit 14, reversing unit 15
When the recording paper arrives at the registration rollers 19, the position in the horizontal direction is not fixed due to the inclination of each unit and the mechanical loss. Therefore, in order to check the lateral shift of each unit in advance and correct the shift before recording an image, a correction value (adjustment value) corresponding to the amount to be corrected is set in the dip switches 50, 51, and 52. Keep it. The operation of setting the correction amount to the dip switches 50, 51, 52 by examining the misregistration of this lateral resist is performed when the machine is used for the first time, etc.
Usually there is no need to reset.

Upon receiving a print request from the controller 58,
If the main unit control unit 53 is not in the BUSY state, the drive control unit
A control signal is sent to 57 to drive the optical system unit 3.
When the synchronization detection signal is output by the synchronization detection sensor 46,
An image clock occurs.

Further, the main body control unit 53 detects whether the unit designated by the user for use is the sheet cassette, the large-volume sheet feeding unit or the reversing unit 15, and determines the value of the DIP switch corresponding to the designated unit. A selection signal is sent to multiplexer 54 for selection. Based on the selection signal, the multiplexer 54 switches the DIP switches 50, 51, 52
The output of the selected dip switch is set to the lower bit of the programmable counter 55. The counter 55 is set to the initial value as described above, and thereafter, upon receiving the synchronization detection signal, starts counting the image clock WCLK from that point. When the count value becomes 00H, a carry is output and transmitted to the main body control unit 53 via the decoder 56, and the time is defined as the start of image writing (Z in FIG. 4).

For example, when the counter 55 and 8 bits, sets the value of the DIP switch to the data terminal b0 to b3, to connect the data terminal b4 to b7 of the upper bits to V _CC.

The misregistration of the lateral resist may be shifted to the left or right in the lateral direction by the machine, or may not occur at all.Therefore, there is no misalignment to cope with any of these. The value of the dip switch corresponding to the case where the horizontal resist is normal (correction amount 0) is set to 8H, for example, as shown on the left side in FIG. At this time, as shown in FIG. 6A showing the adjustment of the writing start position of the image, the position where the carry comes out of the counter 55 is at a distance of a predetermined constant value from the left end of the recording paper indicated by the solid line ( (Indicated by a dashed line).

When the position of the horizontal registration of the recording paper is shifted in the y direction in FIG. 6, the dip switch is set to be smaller than the normal value of 8H in order to adjust the shift. Then, the counter 55 outputs a carry after counting more than the normal case, so that the image writing start position is relatively relative to the recording paper (shown by the solid line) as shown by the broken line in FIG. 6B. Adjusted to be correct.

When the position of the horizontal registration of the recording paper is shifted in the x direction in FIG. 6, the dip switch is set to be larger than the normal value of 8H in order to adjust the shift. Then, the counter 55 outputs a carry after counting less than the normal case, so that the image writing start position is relatively correct with respect to the recording paper (shown by the solid line) as shown by the broken line in FIG. 6C. It is adjusted to become.

After outputting the carry of the writing start position of the image, the counter 55 continues counting, and when the count of the counter reaches a predetermined value, this is detected by the decoder 56 and a signal representing the writing end position W of the image is obtained. To the main unit control unit 53. Since the write end position differs depending on the size (width) of the recording paper, the decoder is provided in accordance with the detection by the recording paper size detection means provided in the paper feed cassette.
In step 56, the count value to be decoded is changed to detect an accurate writing end position on the recording paper.

Dip switches are provided for each unit of the paper feed system that affects the horizontal registration of the recording paper feed, so the horizontal deviation of the recording paper due to the characteristics of each unit can be adjusted only by setting the dip switch. Even if a paper feeding unit is used, a constant standard writing start position and writing end position can always be obtained.

In particular, the reversing unit 15 has a long transport path, and a switchback operation or the like is performed, so that the displacement tends to be large. Moreover,
When the reversing unit 15 is used, since the recording is performed on the front and back of the recording paper, the misalignment is conspicuous and precise adjustment is required. It becomes complicated and the adjustment work becomes troublesome. According to this example, the configuration for adjusting the lateral registration is simple, the control is easy, and the cost is also easy.

Next, the movement control of the first discharge roller pair 21 and the second discharge roller pair 22 will be described.

Even if the writing start position is adjusted so that the relative image writing start position with respect to the recording paper becomes correct, the positional deviation of the horizontal registration of the recording paper itself has not been eliminated. Shifts in the paper discharge position.

The displacement of the paper discharge position on the paper discharge tray is caused by a factor from the paper feed cassette to the paper discharge tray, but substantially coincides with the above-described positional deviation of the lateral registration. The dip switch is used to check the positional deviation of the lateral registration, to correct the deviation, and to record a document, so that the correction amount of the image writing start position is set. If the recording paper is moved in the horizontal direction by the correction amount of the writing start position, the recording paper can be discharged to a predetermined discharge position on the discharge tray.

Therefore, in the present embodiment, during the sheet discharging operation by the first sheet discharging roller pair 21 or the second sheet discharging roller pair 22, the roller pair is set to the correction amount of the image writing start position by the setting of the dip switches 50, 51, and 52. The recording paper is moved in the roller axis direction so that the recording paper is shifted only in the horizontal direction, thereby correcting the discharge position of the recording paper.

First, a roller moving mechanism for moving the first paper discharge roller pair 21 and the second paper discharge roller pair 22 in the roller axis direction will be described.

Since both roller pairs 21 and 22 are moved in the roller axis direction by the same mechanism, the roller moving mechanism of the second sheet discharging roller pair 22 will be described here.

FIG. 7 is a schematic structural view of this mechanism, FIG. 8 is an exploded view thereof, FIG. 9 is a view showing the main part thereof, and FIG. 10 is an arrow A in FIG.
FIG. 11 is a sectional view taken along line BB of FIG. 9,
FIG. 12 is a view showing the shape of the rotating shaft in FIG.

The axis of the upper roller 60 and the axis of the lower roller 61 are supported by an apparatus side plate (not shown) so as to be movable in the horizontal direction while being parallel to each other.
They are connected by a lever 65 whose axial position is regulated by rings 63, 64. The lower end of this lever 65 has a second
A detection member 67 that is detected by a home position sensor 66 disposed at the home position of the paper discharge roller pair 22 is provided. Also, both rollers 60 and 61 are provided with a plurality of large-diameter portions at positions facing each other, and the large-diameter portions of each other are upper rollers.
The recording paper is conveyed by rotating while holding the recording paper between the pressed parts by its own weight or spring pressure. The shaft of the lower roller 61 is spaced at a predetermined interval from E
A pair of rings 69 is fixed, and an upper end of a transverse feed member 72 in which a rotary shaft 71 driven by a motor 70 penetrates a hole formed in a lower end of the transverse feed member 72 is provided in a gap between the E-ring pair 69. Intervening. The transverse feed member 72 is rotated by a ball 74 that partially enters a transverse feed groove 73 formed in the peripheral surface of the rotary shaft 71 and a hole formed in the wall surface of the hole of the transverse feed member 72. Is engaged. The rotating shaft 71 is rotatably supported by a bearing at a localization value in the apparatus, and a rotating force is transmitted by a motor 70 via a rotating shaft gear 75 and a motor gear 76.

When the motor 70 rotates, the rotation is transmitted to the rotating shaft 71 via the motor gear 76 and the rotating shaft gear 75, and the lateral feed member 72
Try to rotate through 74. However, since two points are regulated by the lower roller 61 and the rotating shaft 71, the transverse feed member 72 cannot rotate, and the ball 74 is not grooved on the circumferential surface of the rotating shaft 71.
The traverse member 72 moves in the direction 73 and is pushed by the ball 74 so that the traverse member 72 also moves in the lateral direction. Due to the lateral movement of the traverse member 72, the lower roller 61
The upper roller paired with the lower roller 61 shaft at the same time by pushing the E-ring pair on the shaft of 61
The 60 axis is also moved laterally. Then, by changing the rotation direction of the motor 70, the direction of the lateral feed of the conveying roller pair can be changed.

Next, the correction of the discharge position of the recording paper by the control of the motor 70 in the upper roller driving mechanism will be described.

In this example, a description will be given of a case where the discharge position of the recording paper is corrected for a double-sided print in which the conveyance distance is longer than that of the single-sided print and the deviation of the discharge position of the recording paper is relatively large.

In FIG. 7, reference numeral a denotes a second pair of discharge rollers 22 for printing only one side and discharging recording paper to the second discharge tray 12.
The position b of the recording paper in the vicinity and the position b in the vicinity of the second discharge roller pair 22 when performing the double-sided printing and discharging the recording paper to the second discharge tray 12 are shown. Since double-sided printing has a longer transport distance than single-sided printing, it is shifted by a predetermined amount in the horizontal direction with respect to single-sided printing. Here, this deviation amount is assumed. The discharge position when the mask printing is performed and the recording paper is discharged to the second discharge tray 12 is set as the reference discharge position, and the same applies when the recording paper that performs the double-side printing is discharged to the second discharge tray 12. The paper discharge position at the time of double-sided printing is corrected so that the paper is discharged in the opposite direction in the horizontal direction by this shift amount so that the paper is discharged to the paper discharge position. Then, as described above, in the correction of the image writing start position, for example, the deviation amount is determined by comparing the end positions of the image of the recording paper on which the image is recorded on both sides by performing double-sided printing. In addition, it substantially coincides with the amount of deviation of the lateral registration position during backside recording from the lateral registration position during frontside recording. Therefore, in order to correct the shift amount of the horizontal registration position by using the dip switch 52, the discharge position is corrected in the lateral direction in the opposite direction by the correction amount of the image writing start position on the recording sheet passing through the reversing unit 15. .

FIG. 13 is a functional block diagram of a main body control unit for performing such control.

The movement direction selection means 80 selects the rotation direction of the motor 70 according to the set value of the dip switch 52, and sends a selection signal to the motor 70 drive control circuit 81. The motor driving signal generating means 82 is provided with a motor 70 in the moving mechanism of the second discharge roller pair 22 for moving the recording paper in the lateral direction by the lateral correction amount of the discharge position in accordance with the set value of the dip switch 52. Is driven by the motor drive control circuit 81 during the paper discharge operation by the second paper discharge roller pair 22 after the passage detection signal of the trailing edge of the recording paper from the upper paper discharge sensor 29 is generated. It sends out a signal. Specifically, for example, the calculation of the drive time is a process of calculating the relationship between the set value of the dip switch 52 and the motor drive time using an arithmetic expression, a process of looking up a table storing the correspondence between the two as data, and the like. It is realized by. For example, assuming that there is a possibility that the positional deviation amount of the lateral registration of the machine may be up to ± 3, by setting the setting value of the dip switch 52 to one larger value or smaller value, for example, the image writing start position by / 2 is set. The relationship between the set value of the dip switch 52 and the correction amount of the image writing start position is set so that correction can be performed (for example, if the maximum deviation amount 3 is 3.6 mm, the image writing start position is corrected by 0.6 mm). If so, the relationship between the set value of the DIP switch 52 and the motor drive time is determined in the same manner. The generation of the drive signal of the above drive time is a counter that sets an initial value according to the above motor drive time, starts counting down by a signal from the upper paper ejection sensor 29, and outputs a signal when the count value becomes 00H. And output means for outputting a signal to the motor drive control circuit 81 during the counting operation of the counter. The return rotation signal generating means 83 is a return rotation signal for returning the moved roller pair 22 to a predetermined home position after the discharge operation is completed when the second discharge roller pair 22 or the like is moved for correction of the discharge position. Is to occur. Specifically, for example, when the motor drive signal is generated by the motor drive signal generating means 82, the motor is driven after completion of the paper discharge operation until the home position sensor 66 detects the return of the second discharge roller pair 22 to the home position. This is realized by a process of giving a drive signal to the drive control circuit 81.

 Next, the operation will be described.

When the set value of the dip switch 52 is 8H corresponding to the correction amount 0 of the image writing start position, the movement of the second conveying roller pair 22 is not performed.

In the case other than the set value of the dip switch 52, for example, the horizontal registration position is shifted to the left as in the case of FIG.
Accordingly, when the set value is set to AH as shown on the right side of FIG. 5 to correct the image writing start position to the left, the horizontal position of the recording paper near the second discharge roller pair 22 is set. Since the position in the direction is also shifted to the left as shown in FIG. 6,
When the trailing end of the recording sheet is further conveyed away from the second conveying roller pair 28 and the passage of the trailing end of the recording sheet is detected by the upper sheet ejection sensor 29, the motor 70 is rotated in a predetermined direction to rotate at the home position. The second discharge roller pair 22 is moved rightward by the same amount as the correction amount of the image writing start position corresponding to the set value AH. When the discharge of the recording paper onto the second paper discharge tray 12 is completed, the motor 70 is operated by the second paper discharge roller pair until the home position sensor 66 detects the return of the second paper discharge roller 22.
The motor 70 is stopped after rotating in the direction opposite to the direction in which the 22 is moving.

Similarly to the correction of the discharge position in the discharge using the second transport roller 22, the correction of the discharge position in the discharge using the first transport roller 21 is also performed.

As described above, according to the present embodiment, the deviation of the paper discharge position can be suppressed within the unit (/ 2) for correcting the image writing start position and the paper discharge position corresponding to the setting unit of the set value of the dip switch. The stacking accuracy on the paper discharge tray can be improved.

Further, since the lateral deviation of the recording paper is corrected by the paper discharge roller positioned immediately before the paper discharge unit, after the correction, the recording paper is further transported along a transport path that causes the lateral deviation. As a result, the lateral displacement does not occur again.

Further, since the dip switch for setting the correction amount of the image writing start position is also used for setting the correction amount of the discharge position, the number of components can be reduced.

In the above description of the embodiment, the case where the lateral displacement of the discharge position in the case of recording the double-sided print fed from the reversing unit 15 is corrected has been described. The present invention can also be applied to a sheet discharged to a sheet discharge section.

As means for setting a correction amount for correcting a lateral shift of the sheet discharge position, a correction amount setting means for the image writing start position is also used. However, instead of this, a correction amount setting for the sheet discharge position correction is used. Means may be provided separately.

〔The invention's effect〕

As described above, according to the first or second aspect of the present invention, the moving amount setting unit is configured to discharge the recording sheet to the predetermined position of the sheet discharging unit while canceling the shift of the sheet discharging position in the horizontal direction. The moving amount is set in the recording paper discharging operation, and the conveying member is moved in a direction perpendicular to the recording paper conveying direction by the moving means according to the set moving amount during the recording paper discharging operation. Since the paper is discharged to the predetermined position, the recording paper can be corrected in the horizontal direction at the stage of discharging to the paper discharge unit with a simple configuration, and the stackability of the recording paper in the paper discharge unit is improved.

Further, since the adjustment of the horizontal latent image formation position on the latent image carrier by the optical system unit and the adjustment of the recording paper discharge position at the paper discharge unit are performed, the image on the recording paper due to the shift of the horizontal registration is adjusted. Can be prevented from being displaced relative to each other, and the stackability of the recording paper in the paper discharge unit can be improved.

Further, since the moving amount of the conveying member is set according to the adjustment amount, the measurement for adjusting the paper discharge position can be omitted.

In particular, according to the second aspect of the present invention, in an image forming apparatus for forming an image on both sides of a recording sheet, the adjusting means adjusts a latent image forming position for forming an image on the back side. Since the moving means moves the conveying member during the paper discharging operation after the image formation on the back surface according to the amount, the conveying path of the recording paper in the apparatus is relatively long, and the lateral registration and the amount of lateral displacement Even in this type of image forming apparatus in which the deviation tends to be relatively large, these deviations can be effectively prevented.

[Brief description of the drawings]

FIG. 1 is a front view showing an example of a laser printer to which the present invention is applied. FIG. 2 is a diagram showing the configuration of the optical system unit in FIG. FIG. 3 is a diagram for explaining the relationship between the synchronization detection position and the image area and the adjustment of the horizontal registration position. FIG. 4 is a block diagram of the electrical unit. FIG. 5 is a diagram for explaining setting of an adjustment amount by a dip switch. FIG. 6 is a diagram for explaining the adjustment of the image writing start position, and FIG.
FIG. 3C shows the case where it is shifted in the y direction of FIG. 3, and FIG. 3C shows the case where it is shifted in the x direction of FIG. FIG. 7 is a schematic configuration diagram of a moving mechanism of a second paper discharge roller in FIG. FIG. 8 is an exploded view of the moving mechanism of FIG. FIG. 9 is a view showing a main part of the moving mechanism of FIG. FIG. 10 is a view not seen from the direction of arrow A in FIG. FIG. 11 is a sectional view taken along line BB of FIG. FIG. 12 is a view showing the shape of the rotating shaft in FIG. FIG. 13 is a functional block diagram of an electrical unit for controlling the moving mechanism of FIG. DESCRIPTION OF SYMBOLS 1 ... Printer body, 2 ... Photoreceptor drum 3 ... Optical system unit, 7 ... Process unit 8 ... 1st paper feed cassette, 9 ... 2nd paper feed cassette 11 ... 1st paper output tray, 12 Second discharge tray 13 Third discharge tray 14 Large-volume feeding unit 15 Reversing unit 21 First discharge roller pair 22 Second discharge roller pair 23 Second 3 discharge roller pair 28… second transport roller pair 29… upper discharge sensor 50,51,52… dip switch 53… main unit control unit 55… preset counter 60… upper roller 61… lower Roller 70 …… Motor 71 …… Rotating shaft 72 …… Side feed member 74 …… Ball 75 …… Rotating shaft gear

Claims (2)

(57) [Claims] 1. A paper feeding means for feeding a recording paper to a recording section provided with an optical system unit and a latent image carrier via a conveyance path, and a paper discharge for conveying the recording paper from the recording section to a paper discharge section. Moving means for moving a conveying member of the conveying device for applying a conveying force to the recording paper in a direction perpendicular to the recording paper conveying direction during the recording paper discharging operation; Moving amount setting means for setting a moving amount; adjusting means for adjusting a horizontal latent image forming position on the latent image carrier by the optical system unit; adjusting amount setting means for setting an adjusting amount by the adjusting means Wherein the moving amount is set according to the adjustment amount. 2. A sheet feeding means for feeding a recording sheet to a recording section provided with an optical system unit and a latent image carrier via a conveyance path, and a sheet discharging section for conveying the recording sheet from the recording section to a sheet discharging section. Having a device, after conveying one surface of the recording paper to the recording unit to form an image, by conveying the back surface of the one surface of the recording paper to the recording unit to form an image, In an image forming apparatus for forming an image on both sides of a recording sheet, during a recording sheet discharging operation after forming an image on the back side, a conveying member of the conveying apparatus for applying a conveying force to the recording sheet is moved in a recording sheet conveying direction. Moving means for moving in a vertical direction; moving amount setting means for setting a moving amount by the moving means; and a latent image on the latent image carrier by the optical system unit for forming an image on the back surface. Adjusting means for adjusting the forming position; adjusting amount setting means for setting an adjusting amount by the adjusting means; An image forming apparatus comprising: a step; and setting the movement amount according to the adjustment amount.