JP2558826B2 - Image forming device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electronic copying machine or a laser printer, and in particular, temporarily accommodates a sheet in a sheet conveyance path and aligns the width of the sheet. The present invention relates to an image forming apparatus including a width adjusting unit.

2. Description of the Related Art For example, in an electronic copying machine capable of performing double-sided copying, an intermediate tray that temporarily accommodates paper in the re-feeding conveyance path for copy paper that has completed copying on one side has a poor accommodation to improve the recovery from the intermediate tray. A width adjusting mechanism is provided in order to suppress the occurrence of jams during paper feeding. For example, JP-A-61-2544
In No. 31, when the paper copied on one side is conveyed to the intermediate tray, the motor rotates and the movable regulation plate is set to the maximum distance from the fixed regulation plate, and then the motor is rotated forward to move. The regulation plate was moved closer to the fixed regulation plate, and the motor and the motor were rotated for a while after the side edges of the paper were detected by the lamps and light-receiving elements provided above and below this movable regulation plate, and the distance between the regulation plates had been conveyed. The width of the paper is adjusted by making it slightly narrower than the width of the paper, and then rotating the motor in the reverse direction to stop the movable regulation plate while making it slightly wider than the width of the paper.

However, in the above-mentioned conventional example, since the lamp and the light receiving element are used as means for detecting the side edge of the paper,
If paper powder, toner, or the like adheres to either one of these lamps or light receiving elements, there is a possibility that erroneous detection or detection failure may occur. Further, it is difficult to reliably detect the side edge of the sheet due to variations in the lamp, spread of the luminous flux, irregular reflection, and the like.

The present invention has been made in view of such points,
An object of the present invention is to provide an image forming apparatus capable of always accurately detecting the side edge of a sheet regardless of the adhesion of paper powder, toner, etc., and improving the reliability of width alignment.

Means for Solving the Problems In order to achieve the above object, the present invention includes a width adjusting unit that temporarily accommodates a paper in a paper conveying path and adjusts the width of the paper. An image forming apparatus including a guide plate, a second guide plate that can be driven in a direction parallel to the first guide plate and perpendicular to the first guide plate, and a drive unit that drives the second guide plate. A pressure sensor which is arranged on at least one inner wall of the guide plate and responds to the pressure of the sheet applied to the one guide plate, and the second sensor which approaches the first guide plate for width adjustment. Control means for controlling the drive means is provided so as to control the return of the guide plate based on the output of the pressure sensor.

Operation According to this structure, first, the second guide plate is driven so as to approach the first guide plate as the drive means operates. Then, when the first guide plate comes into contact with the sheet conveyed to both guide plates, a force is applied to the pressure sensor provided on one guide plate, and an output signal is generated from this pressure sensor. The control unit inputs this output signal and controls the drive means in the reverse direction based on the signal. Therefore, the second guide plate is returned in the direction away from the first guide plate.

Example An example shown in the drawings will be described below.

FIG. 2 schematically shows the structure of an electronic copying machine capable of double-sided copying, and (1) is its frame. (2) is a photosensitive drum that rotates at a low speed, and this drum (2)
Around the periphery of, along the rotation direction thereof, a charging section (3), an exposing section (4), a developing section (5), a transfer section (6), a separating section (7),
A cleaning unit (8) and a charge eliminating unit (9) are provided in this order. (10) is an exposure lamp. (11) shows a contact glass, and (12) shows an original pressing member.
The light emitted from the exposure lamp (10) and reflected by the document is guided to the exposure unit (4) through the range systems (13) and (14).
The developing section (5) has a developing roller (15). Paper is applied to the transfer unit (6) from the paper feed unit (16) or the paper refeed unit (17). The fed paper is the exposure drum (2)
After the upper toner image is transferred, it is supplied from the separating section (7) to the fixing section (19) through the conveying section (18), and the fixing is performed there. (20) shows a first roller for fixing, and (21) shows a second roller which is in pressure contact with it. The fixed paper is discharged onto the paper discharge tray (24) by the discharge rollers (22) and (23). Paper feed cassette (25a) in the paper feed section (16)
(25b) (25c), paper feed rollers (26a) (26b) (26c), paper feed rollers (27a) (27b) (27c), etc. are provided. The re-feeding unit (17) is used for double-sided copying, and is a reversing unit (37) for reversing the sheet on which one side of the image has been fixed through the fixing unit (19). Conveyor rollers (29) and (30) that send the paper to the (50), a reverse discharge switch (31) that detects the passage of the paper, and an inclined table (3 that slides the paper down.
2) Consists of a width adjusting unit (33) for temporarily accommodating the paper sent from the tilting table and for adjusting the width of the paper, a forward feed roller (34), conveying rollers (35) (36), etc. ing.

As shown in FIG. 1, the width adjusting unit (33) has a fixed guide plate (39) formed by bending one end of a bottom plate (38) upward, and an elongated hole (40) on the bottom plate (38). An elastic member (42) having one end fixed and the other end free to the inner wall of the movable guide plate (41). A pressure sensor (43) with which the other end contacts is provided. The pressure sensor (4
A piezoelectric element is used in this embodiment as 3), but another element that responds to the applied pressure may be used. A motor (44) and a drive wire (45) moved by the motor are arranged on the back surface of the bottom plate (38), and the movable guide plate (41) is fixed to the drive wire (45).

FIG. 3 shows a circuit system that controls the drive of the motor (44). In the figure, reference numeral (46) is a control unit, which is composed of, for example, a microcomputer. The control section (46) has a plurality of I / O cells (47) (48) (49), and exchanges signals with external circuits via the I / O cells. When the reverse discharge switch (31) pushed into the re-feeding conveyance path (50) is turned on, the ON signal is converted into the normal rotation drive signal of the motor input to the control section (46). (Five
1) is a motor drive circuit, which operates based on a control signal given from a control section (46) to drive a motor (44). The output of the pressure sensor (43) is the amplifier (52) and A /
It is input to the control unit (46) through the D converter (53).

 The operation will be described below with reference to the flowchart.

In FIG. 4, when the copy start switch is turned on, the copy paper fed from the paper feed unit (16) is transferred to the transfer unit (6), separation unit (7), conveyance unit (18), fixing unit (19). ),
It is sent to the re-feeding conveyance path (50) via the reversing section (37). Meanwhile, the movable guide plate (4
1) is moved to a position that is sufficiently wider than the paper size.
The control unit (46) monitors that the reverse discharge switch (31) is turned on in step (# 1), and when the switch (31) is turned on, the timer set and the motor ( 44) Forward rotation is performed. The timer in this case may be the one built in the microcomputer that constitutes the control section (46). Here, the timer set means a set of a timer flag and a set of a counter value.

This timer set, as shown as the [Timer1] interrupt routine in FIG.
Check the state of the timer flag with, and if the timer flag is cleared, proceed to NEXT. If it is set, the counter value is decremented by 1 in step (# 105), and the counter is incremented in the next step (# 110). It is judged whether the decremented result is 0 from the value. If it is not 0, it proceeds to NEXT, and if it is 0, the motor (44) is rotated forward in step (# 115), and step ( # 120) to clear the timer flag. This interrupt routine is executed every 1 msec.

In this way, when the motor (44) rotates in the normal direction, the movable guide plate (41) moves in a direction approaching the fixed guide plate (39). Then, the width adjustment unit (3
3) When the paper that has entered the movable guide plate (41) hits,
Pressure is applied to the pressure sensor (43) via the elastic member (42), and a relatively large output is produced from the pressure sensor. The output signal is amplified by the amplifier (52) and then the A / D converter (5
It is converted to a digital value in 3) and input to the control section (46). The control unit (46) takes in the signal via the I / O cell (49) and determines whether or not the signal is equal to or more than a preset reference value (# 3). When the value is less than the reference value, the output of the pressure sensor (43) and the reference value are repeatedly compared. When the value exceeds the standard value, proceed to step (# 4) and set the motor (44).
Reverse. The reverse rotation of this motor is a movable guide plate (41)
Is moved (returned) in the direction away from the fixed guide plate (39).

Next, in step (# 5), after waiting for the output of the pressure sensor (43) to become smaller than the reference value, the process proceeds to step (# 6) to set the timer and stop the motor. This interrupt routine [Timer2] will be described with reference to FIG. In this step, the state of the flag of the timer is determined in step (# 200). If the flag is cleared, the process proceeds to NEXT. If it is set, the counter value is incremented by 1 in step (# 205).
Decrement. Then, in step (# 210), it is judged whether or not the result becomes 0. If not 0, NEXT
If it is 0, the motor (44) is turned off at (# 215), and then the timer flag is cleared at step (# 220) to proceed to NEXT.

Returning to FIG. 4, after passing through step (# 6), it is determined in step (# 7) whether or not all copying is completed. If NO, the process returns to step (# 1) and the above flow is repeated. If YES, go to NEXT. Incidentally, when the motor (44) is stopped in step (# 6), the movable guide plate (41) is stopped at the position of the sheet size 10α. When copying continuously,
The above operation is repeated every time the reverse discharge switch (31) is turned on.

In the present embodiment, the stop position of the movable guide plate (41) after returning may be the home position, but as described above, the time from the point where the movable guide plate returns based on the output of the pressure sensor. Is set appropriately so as to stop before the home position (in other words, α of the above-mentioned paper size 10α is set), and it takes a short time until the next width adjustment. Benefits are obtained. Then, in this case, the movable guide plate (41) always waits at a point separated from the side edge of the sheet by a distance irrespective of the size of the sheet. In the above-described embodiment,
Although the width adjusting unit in which one is the fixed guide plate and the other is the movable guide plate is illustrated, the invention is not limited to this, and both types may be movable guide plates. In the present specification, the first guide plate in the claims corresponds to the fixed guide plate 39 in the above embodiment, and the second guide plate corresponds to the movable guide plate 41. Also,
The drive means corresponds to the motor drive circuit 51 and the motor 44. The control means 46 corresponds to the control unit 46.

ADVANTAGEOUS EFFECTS OF INVENTION According to the present invention, the return of the second guide plate, which is moved so as to sandwich the paper between the first guide plate for width adjustment, is used as the output signal of the pressure sensor that responds to the contact pressure of the paper. Since the control is performed on the basis of the pressure sensor, the side edge of the sheet can always be accurately detected even if paper dust, toner, or the like is attached to the pressure sensor. Therefore, the reliability of the width matching operation is improved, and the occurrence of paper stock defects and jams can be avoided.

Further, since the second guide plate is turned back by the output of the pressure sensor, by setting the time until the second guide plate is stopped after the turning back, it is possible to set the following for any size of paper (however, smaller than the home position). The distance from the standby position for the width adjusting operation to the sheet side edge can be made uniform.

[Brief description of drawings]

FIG. 1 is a perspective view of a width adjusting unit portion in an image forming apparatus embodying the present invention, and FIG. 2 is a schematic view showing an entire electronic copying machine equipped with the width adjusting unit, and FIG. Is a block diagram showing a circuit for driving and controlling a motor, and FIGS. 4, 5, and 6 are flowcharts showing an operation flow. (33) …… Width adjustment unit, (39) …… Fixed guide plate, (41) …… Movable guide plate, (43) …… Pressure sensor, (44) …… Motor, (46) …… Control section, (50) …… Re-feeding conveyance path.

Front Page Continuation (72) Inventor Toshinobu Katabuchi 1-22 Tamatsukuri, Higashi-ku, Osaka, Osaka Prefecture Mita Industry Co., Ltd. (72) Eiji Nakajima 1-2-2 Tamatsukuri, Higashi-ku, Osaka City, Osaka Mita Industry Co., Ltd. In-house (72) Inventor Yoshiaki Tabata 1-2-2 Tamatsukuri, Higashi-ku, Osaka-shi, Mita Sanda Kogyo Co., Ltd. (72) Inventor Nobuyuki Hirata 1-2-28 Tamatsukuri, Higashi-ku, Osaka-shi, Osaka Mita Kogyo Co., Ltd.

Claims (3)

(57) [Claims] 1. A width aligning unit for temporarily accommodating a sheet in a sheet conveying path and aligning the sheet width,
The width adjusting unit includes a first guide plate, a second guide plate that can be driven in a direction parallel to the first guide plate and perpendicular to the first guide plate, and a driving unit that drives the second guide plate. In the image forming apparatus, the pressure sensor is disposed on at least one inner wall of the guide plate and responds to the pressure of the sheet applied to the one guide plate, and the first guide plate for width adjustment. The image forming apparatus is provided with a control means for controlling the driving means so as to control the return of the second guide plate approaching to the position based on the output of the pressure sensor. 2. The image forming apparatus according to claim 1, wherein the pressure sensor comprises a piezoelectric element. 3. The image forming apparatus according to claim 1, wherein the control means comprises a microcomputer.