JP2628810B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a PPC, a printer,
The present invention relates to an image forming apparatus such as a facsimile and, more particularly, to control of sheet conveyance timing.

[0002]

2. Description of the Related Art Generally, in a transfer type image forming apparatus for transferring a document image (an electrostatic latent image or a visible image) formed on a photoreceptor onto a sheet to obtain a copy, the sheet conveyed by a conveying unit After the start of conveyance of the sheet, a registration means is provided for feeding the sheet in a timely manner so as to correspond to the image position on the photosensitive member. The registration means has a very important function to play a timely delivery in order to match the sheet on which the image is transferred to the image position on the photoconductor.

In the above-described paper feed timing control method, the phase of a rotating body that rotates synchronously with the photosensitive body is detected by a microswitch, and the solenoids of the clutches of the respective paper conveying means are operated in accordance with a signal generated by the microswitch. Had been activated. However, there is a variation in response time from when the signal is generated by the microswitch to when the solenoid actually operates. For this reason, it cannot be expected that the sheet transport operation is performed at an accurate timing. Furthermore,
Especially in the case of thin paper, the pressing force of the transport roller
Wrinkling is likely to occur, and for thick paper,
There are drawbacks such as that the conveyance becomes impossible due to the insertion angle of the nip portion of the conveyance roller.

In order to cope with the above, as shown in FIG. 6, there is provided a resist member which is disposed downstream of the sheet conveying means and prevents the advance of the sheet at the first position and releases the inhibition at the second position. There is disclosed an image forming apparatus provided with a sheet transport unit configured to move from a first position to a second position in mechanical cooperation with an optical scanning member of a document (Japanese Patent Publication No. 2746462). Reference).

In FIG. 6, when the main switch is turned on, the original placing table 1 moves to the original exposure position, and when the copy button is pressed, the original placing table 1 starts moving and starts exposing the original. The sheet is fed by sheet transport rollers 7a and 7b. When the leading edge of the sheet abuts against the resist plate 32 and is aligned so as to be parallel to the axis of the photoconductor 3, the upper roller 7a stops and the lower roller 7b idles. I do. Therefore,
The forked portions 31a and 31b of the lever 28 descend to lower the resist plate 32 and open the transport path 36. When the transport path 36 is opened, the sheet is sent again to the photoconductor 3 by the sheet transport rollers 7a and 7b. After the trailing edge of the sheet has passed through the resist plate 32, the pin 20 is moved from the raised portion 19b to the groove portion 19 again.
When returning to a, the resist plate 32 closes the transport path 36 again.

[0006]

However, according to the above-mentioned technique, the document table is stopped with the registration plate lowered and the conveyance path opened due to a paper jam or the like, and the document table is returned to the home position. When the paper is inserted when the printer is restarted, the paper is conveyed toward the photoreceptor because the conveyance roller is activated, and the timing may be shifted, resulting in erroneous copying.

In view of the above, in the present invention, when the optical system scanning unit is stopped with the transport path opened and the optical system scanning unit is restarted without returning to the home position, paper is inserted. Another object of the present invention is to provide an image forming apparatus capable of preventing insertion of paper and preventing erroneous copying.

[0008]

This onset bright [Means for solving problems], along the transport path and the image forming unit to transfer to the paper after the visualized document image formed on the photosensitive member, the paper from the opening photosensitive In an image forming apparatus having a paper transport unit that transports the paper to the body, a transport blocking unit that locks the leading edge of the paper transported along the transport path and temporarily waits for the paper before the photoconductor , a blocking position to prevent the progression of the paper to engage with the conveyance blocking portion, to take a blocking release position directing to release the locked state of the sheet conveying blocking portion the sheet to the photoreceptor, rotatable The registered resist guide and the resist guide at a predetermined timing
A switching mechanism for switching between a posture and an unblocking posture, and a registration mechanism, which is provided in the registration guide, is displaced to a position such that it comes into contact with a sheet inserted from a paper feed port in front of the sheet conveyance unit when the registration guide is in the blocking position; A switch that is displaced to a position where it does not come in contact with the paper inserted from the paper feed port before the paper transport unit when the registration guide is in the blocking release position.
The paper transport unit includes a leading edge of the inserted paper.
The drive starts in response to contact with the switch, and the paper
The image forming apparatus is characterized in that the driving is stopped in response to the release of the switch .

[0009]

According to the present invention, the registration guide has a blocking posture.
When the paper from the paper feed port is inserted to have a state in which taking, the paper
Tip to abut the switch, the drive start of the sheet conveying portion of the
Is, Ru is conveyed sheets to the photoconductor side. Depending on the paper transport
Sheet conveyed Te, the tip of that is engaged with the transport blocking portion, Ru temporarily stand in front of the photosensitive member.

Thereafter, the registration guide is operated by the switching mechanism.
If is switched to enter blocking release position from deter posture at a predetermined timing, the sheet is Ru is supplied toward the photosensitive member. So
When the paper leaves the switch, the paper transport
Is stopped . So, for example, the registration guide
Optical scanning unit is stopped when the blocking release state, device is restarted without feeding back the optical scanning unit to the home position, be inserted sheet feeding port, the paper does not come into contact with the switch since, the driving of the paper conveying portion is Ru or <br/> or der that is stopped. Therefore, the paper is not conveyed toward the photoconductor by the paper conveyance unit, and the rotation of the photoconductor and the supply of the paper are performed.
Offset timing with the sheet is missed the copy is generated
There is no. Also, in response to the switch on / off, the paper
Since the feed unit is driven / stopped, the paper transport unit is constantly driven.
Power consumption can be reduced compared to
Thus, the running cost of the apparatus can be reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a diagram showing a state before a sheet is inserted in an image forming apparatus according to an embodiment of the present invention, FIG. 2 is a diagram showing a state when an optical system scanning unit moves backward, and FIG. Front view showing the position of the switch in the state of
FIG. 4 is a diagram showing a state when the optical system scanning unit moves forward and returns to the home position, and FIG. 5 is a front view showing the positions of the switches in the state shown in FIG.

Referring to FIG. 1, reference numeral 50 denotes an apparatus main body; and 51, an original image is formed on a photoreceptor 52 by reciprocating on the apparatus main body 50 for optical scanning of the original so as to be freely reversible (left and right). An optical scanning section 53, a paper transport section 53 for transporting the paper to the photoreceptor 52, an image forming section 54 for visualizing the original image formed on the photoreceptor 52 and then transferring it to the paper, and a reference numeral 56 A fixing section for fixing the toner image transferred to the sheet, the apparatus main body 50 includes a sheet transport section 53, a photoreceptor 52, an image forming section 54, and a fixing section 56 in this order. Incidentally, 57 in the figure
Is a transport frame fixedly arranged along the transport path, 58
Is a manual feed guide, and 59 is a paper feed port.

The image forming section 54 includes, as shown in FIG.
2, a charging charger, a developing device, a transfer charger, and a cleaner are sequentially arranged. An original image is formed by forming an original image on the outer peripheral surface of the photoconductor 52 uniformly charged by the charging charger. Is developed into a toner image by a developing device, the toner image is transferred to paper by a transfer charger, and residual toner is collected by a cleaner. The image forming unit 54 is supported by an image forming frame 54a. In the drawing, reference numeral 55 denotes a transfer charger and other components of the image forming unit 54 are not shown.

The fixing section 56 includes a heating roller 56a having a built-in heater, and a pressure roller 56b which is pressed against the heating roller 56a from below and is driven to rotate, and is sandwiched between the rollers 56a and 56b to form a sheet. To fix the transferred toner image. Then, in this embodiment, the leading end of the sheet conveyed along the conveyance path from the sheet conveyance unit 53 is locked,
A transport blocking unit 61 for temporarily suspending the sheet in front of the photoconductor 52, and releasing the locked state of the paper locked by the transport blocking unit 61 at a predetermined timing to supply the sheet to the photoconductor 52. An unlocking means 62 is provided.

The transport inhibiting portion 61 is formed of a concave portion provided integrally with the transport frame 57 between the photosensitive member 52 and the manual feed guide 58, and the side surface of the concave portion of the photosensitive member 52 is related to the leading edge of the sheet. The function of stopping the advance of the sheet and maintaining the positional relationship between the sheet and the photoconductor 52, that is, regulating the start position of the sheet. Lock release means 62
Is disposed in a concave portion of the transport blocking unit 61 and transfers the sheet to the transport blocking unit 6 when the optical system scanning unit 51 rotates in the reverse direction (moves leftward).
1 to prevent the paper from advancing.
When the optical system scanning unit 51 rotates forward (moves to the right), the resist that is rotatable so as to release the locked state of the paper in the conveyance blocking unit 61 and take a blocking releasing position to guide the paper to the photoconductor 52. It comprises a guide 63 and a switching mechanism 64 for switching the registration guide 63 between a blocking posture and a blocking releasing posture in accordance with the movement of the optical system scanning unit 51.

The registration guide 63 is formed in a substantially U-shape in cross section so that the upper surface thereof becomes a paper conveyance surface to the photoconductor 52, and is erected from the bottom surface of the conveyance prevention portion (recess) 61. It is supported by a support piece 80 via a horizontal axis 81. As shown in FIGS. 2 to 5, the front end of the registration guide 63 (the end on the side of the manual feed guide 58) comes into contact with the paper inserted from the paper feed port 59 in front of the paper conveyance unit 53 in the blocking position, and A micro switch 120 is provided that drives the transport unit 53 and does not contact the paper inserted from the paper feed port 59 in front of the paper transport unit 53 in the blocking release posture and does not drive the paper transport unit 53. The micro switch 120 includes a switch main body 121 and a contact 122 disposed on the switch main body 121 and configured to contact a sheet and detect insertion of the sheet. Then, the contact 122
Are tiltable with respect to the switch body 121 in the paper advancing direction as the paper advances.

As shown in FIG. 1, the switching mechanism 64 includes a first lever 90 rotatably supported in the vicinity of the optical system scanning section 51 of the apparatus main body 50, and the same in the vicinity of the optical system scanning section 51 of the apparatus main body 50. The optical system scanning unit 51 is rotatably supported by
At the time of forward rotation, the first lever 90
When the optical system scanning unit 51 rotates in the reverse direction, the second lever 91 releases the contact with the first lever 90 to allow the first lever 90 to rotate. A connection lever 92 connected to the other end and pressing the registration guide 63 toward the blocking position; and a connection lever 92 provided on the optical system scanning unit 51. When the optical system scanning unit 51 rotates in the reverse direction, the second lever 91
, The second lever 91 is rotated in the first lever contact release direction to release the pressing of the connecting lever 92 on the registration guide 63 from the blocking posture side,
94, and a biasing spring 95 for biasing the registration guide 63 toward the blocking release position.
The posture of the registration guide 63 is switched mechanically in conjunction with 1.

The first lever 90 and the second lever 91
Are formed in a substantially rectangular shape, and face each other,
It is supported by support pieces 102 and 103 vertically suspended from the upper surface of the apparatus main body 50 via pins 100 and 101. The connecting lever 92 has a pin 110 at the lower end of the first lever 90.
Has been fixed through.

The lever contact members 93 and 94 are arranged so as to correspond to the original image exposure distance of the optical scanning unit 51. The urging spring 95 is a coil spring, one end of which is mounted on the bottom surface of the recess 61 serving as a blocking member, and the other end of which is mounted on the lower surface of the registration guide 63. Further, the paper transport section 53 includes a driving roller 70 and a driven roller 71 which is pressed against the driving roller 70 from below and rotates following the rotation of the driving roller 70. Transport. The driving roller 70 is rotatable about a horizontal axis 130, and the driven roller 71 moves the registration guide 63 when the registration guide 63 assumes the blocking position.
Is further rotatably supported by the registration guide 63 so as to be further pressed against the drive roller 70 and driven to rotate as compared with the stop position. In the drawing, reference numeral 131 denotes a paper guide.

In the above configuration, when a sheet is inserted from the paper feed port 59 through the manual feed guide 58 in the state shown in FIG.
Since the registration guide 63 is in the blocking position, as shown in FIGS.
, And drives the drive roller 70 and the driven roller 71 of the sheet transport unit 53 to transfer the sheet P to the photosensitive member 52.
To the side. Then, the leading end of the paper is
1 and the movement thereof is blocked, and waits before the photoconductor 52. At this time, as shown in FIG.
At the same time as the drive roller 70 and the driven roller 71 are driven, the document is rotated in the reverse direction toward the left side for document scanning, and when fully filled, moves toward the right side (forward rotation) as shown in FIG.

When the lever contact member 93 provided on the scanning unit 51 comes into contact with the second lever 91 as the optical system scanning unit 51 moves to the normal rotation side, the second lever 91 is rotated clockwise. Tilt to release contact with the first lever 90. Then, the first lever 90 enters the free state, and the pressing of the connecting lever 92 against the registration guide 63 is released. Along with this, the registration guide 63 is moved by the urging spring 95.
Is rotated upward by the urging force of (1), and is switched from the blocking position to the blocking releasing position. Therefore, the driving roller 70 and the driven roller 71
The paper is started toward the photoreceptor 52 by the driving force of. In addition, the driven roller 71 moves upward together with the switching of the blocking release posture of the registration guide 63, so that the pressing force against the driving roller 70 is increased.

When the leading end of the sheet reaches the photosensitive member 52, the contact of the sheet with the contact 122 of the switch 120 stops, and the driving of the drive roller 70 is stopped .
At this time, when the optical system scanning unit 51 is stopped due to a cause such as a paper jam, device without feeding back the optical scanning unit 51 to the home position is restarted, as shown in FIG. 4,
Even if the paper P is inserted from the paper feed port 59, the switch 1 is switched with the switching of the blocking release posture of the registration guide 63.
Since the contact 122 of 20 is located on the lower side of the manual guide 58, the leading end of the sheet P does not contact with the contactor 122, the drive roller 70 remains stopped. Therefore, the paper is not conveyed toward the photoconductor 52 by the paper conveyance unit 53, and the insertion of the paper can be prevented before the paper conveyance unit 53. Therefore, the time between the rotation of the photoconductor and the supply of the paper is reduced. > timing is shifted, causing no mistake copy. Ma
A driving roller in response to ON / OFF of the switch 120;
Since the driving roller 70 is driven / stopped, the driving roller 70 is constantly driven.
Power consumption can be reduced compared to when
Can reduce the running cost of the equipment
You.

When the scanning of the original is completed, as shown in FIG. 2, the optical system scanning section 51 changes to the left (reverse) movement, and the lever contact member 94 contacts the first lever 90 to move it counterclockwise. Tilt around. Accordingly, the connecting lever 92
The resist guide 63 against the urging force of the urging spring 95.
Is rotated downward and pressed to switch from the block release position to the block position, the optical system scanning unit 51 returns to the home position, and the copy operation ends. At this time, the contact 122 of the microswitch 120 is located at substantially the same position as the manual feed guide 58 in accordance with the switching of the blocking posture of the registration guide 63, so that when the next paper P is inserted from the paper feed port 59, The driving roller 70 and the driven roller 71 are driven in contact with the leading end of the sheet P, and the sheet P can be inserted.

Further, the transport blocking section 61 is formed integrally with the transport frame 57 disposed along the transport path, and the transport blocking section 61 is engaged with the leading edge of the sheet to temporarily hold the sheet in front of the photoconductor 52. Since the start position of the paper is regulated by making it stand by, the start position of the paper is determined only by the positional accuracy of the transport frame with respect to the photoconductor. Variations in the positional relationship with the start position of the sheet can be suppressed and the sheet can be held accurately. Therefore, even when the locked state of the paper locked by the transport blocking unit 61 by the unlocking means 62 is released at a predetermined timing and the paper is supplied to the photoconductor 52, variations in the leading end position of the paper occur. Therefore, it is possible to prevent the position of the leading edge of the image on the sheet from being shifted.

Further, the unlocking means 62 is provided with the switching mechanism 6
4, the movement of the registration guide 63 is controlled by the optical system scanning unit 51.
Mechanically linked with the optical system scanning unit 51, the responsiveness of the registration guide 63 to the movement of the optical system scanning unit 51 does not vary, and the paper can be reliably sent in time to correspond to the image position on the photoconductor. it can. Further, in the paper transport section 53, the driving roller 7 of the driven roller 71
If the pressure contact force with respect to zero remains small, paper feeding unevenness occurs.
When the registration guide 63 is in the blocking release posture, the registration guide 63 is further pressed against the drive roller 70 and driven to rotate as compared with the registration guide 63 in the blocking position. A strong pressing force is applied to the driven roller 71, and the paper can be reliably transported without providing a transport roller pair between the transport blocking unit 61 and the photoconductor 52.

It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that many changes or modifications can be made to the above-described embodiment within the scope of the present invention. For example, in the above-described embodiment, the same effect can be obtained by forming the transport blocking unit integrally with the image forming frame supporting the photoconductor and releasing the locked state of the sheet by the locking release unit.

The switching mechanism detects the forward / reverse rotation of the optical system scanning unit with a microswitch, and operates a solenoid in accordance with a signal generated by the microswitch to move the guide member into two positions, a blocking position and a blocking releasing position. It is good also as a structure which switches. Furthermore, in the above embodiment, the posture of the guide member is switched in mechanical cooperation with the optical system scanning unit,
Although the switching means has been described as an example in which the first lever, the second lever, the connecting lever, the lever contact body, and the urging spring are used, the guide member is also mechanically interlocked with the optical system scanning unit. Any configuration may be used as long as the position can be switched between the blocking position and the blocking release position.

[0028]

As is apparent from the above description, according to the present invention, for example, when the registration guide is in the blocking release posture,
When the optical system scanning unit is stopped, the device is restarted without feeding back the optical scanning unit to the home position, be inserted sheets from the sheet feeding port, the paper is brought into contact with the switch
Therefore, the driving of the paper transporting unit remains stopped .
Therefore, since the paper is not conveyed toward the photoconductor by the paper conveyance unit, the time between rotation of the photoconductor and supply of the paper is not satisfied.
There is no mis-copying due to misalignment . Ma
In addition, the paper transport unit is driven in response to the switch on / off
/ Stopped, so if you always drive the paper transport
Power consumption can be reduced compared to
Running cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a state before a sheet is inserted in an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a state when an optical system scanning unit moves in a reverse direction;

FIG. 3 is a front view showing a position of a switch in a state of FIG. 2;

FIG. 4 is a diagram showing a state when an optical system scanning unit moves forward and returns to a home position.

FIG. 5 is a front view showing the position of the switch in the state of FIG. 4;

FIG. 6 is a diagram illustrating a sheet transport unit according to a conventional image forming apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 51 optical system scanning unit 52 photoreceptor 53 paper transport unit 59 paper feed port 61 transport blocking unit 62 locking release unit 63 registration guide 120 switch 122 contact

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication location H04N 1/00 108 H04N 1/00 108H

Claims (1)

(57) [Claims] An image forming section for visualizing an original image formed on a photoreceptor and transferring the same to paper, and a paper transport section for transporting the paper from a paper feed port to a photoreceptor along a transport path. an image forming apparatus comprising, engages the leading end of the sheet conveyed along the conveying path, a conveying blocking unit for temporarily waiting the paper in front of the photosensitive member, and to engage with the conveyance preventing portion A rotatable registration guide and a registration guide are provided so as to take a blocking position for preventing the sheet from advancing and a blocking release position for releasing the locked state of the sheet in the conveyance blocking portion and guiding the sheet to the photoconductor. Stopping posture and stopping solution at predetermined timing
A switching mechanism for switching to a release position, and a registration guide, which is provided in the registration guide, and is displaced to a position where it comes into contact with a sheet inserted from a paper feed port in front of the sheet conveyance unit when the registration guide is in a blocking position . a switch that is displaced to a position where it does not come into contact with the sheet inserted from the paper feed port in front of the sheet conveying unit in the blocking release position , and the sheet conveying unit includes: The leading edge of the inserted paper abuts the switch
Drive is started in response to the
An image forming apparatus, wherein the driving is stopped in response to the separation .