JPH0566633A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent copying error by preventing insertion of paper before a paper carrying part by stopping an optical scanning part when a resist guide takes a prevention release attitude, and the paper is not carried toward a photosensitive body from a paper carrying part even when the paper is inserted from a paper feeding opening when the optical scanning part is started again without being returned to a home position. CONSTITUTION:When the paper is inserted, since the resist guide 63 takes the prevention attitude, and a paper carrying part 53 is driven by the paper in contact with a switch 120 and the paper is carried to the photosensitive body 52 side. Thus, a leading tip of the paper is restrained to a carrying prevention part 61, and the paper is made to temporarily stand by before the photosensitive body 52. Then, the resist guide 63 is changed over from the prevention attitude to the prevention release attitude to release the restrained state of the paper restrained to the carrying prevention part 61 at a specified timing, and the paper is fed toward the photosensitive body 52. When the leading tip of the paper reaches the photosensitive body 52, the contact between the switch 120 and the paper is eliminated, and the paper carrying part 53 is not driven.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 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 paper conveyance timing.

[0002]

2. Description of the Related Art Generally, in a transfer type image forming apparatus for transferring a document image (electrostatic latent image or visible image) formed on a photoconductor onto a sheet to make a copy, a sheet conveyed by a conveying section. After the start of the conveyance, the registration means is provided for timing and feeding the paper so as to correspond to the image position on the photoconductor. The registration means has a very important function of playing a role of sending the image on the photosensitive member at a timing so as to align the sheet on which the image is transferred.

In the paper feed timing control system as described above, a micro switch detects the phase of a rotating body that rotates in synchronism with the photosensitive member, and the solenoid of the clutch of each paper conveying means is activated in response to a signal generated by the micro switch. It was working. However, there is variation in the response time from the generation of a signal by the microswitch to the actual actuation of the solenoid. Therefore, it cannot be expected that the paper transport operation will be performed at an accurate timing. Furthermore,
Especially in the case of thin paper, the pressing force of the transport roller causes
If thick paper is used, wrinkles are likely to occur.
There is a drawback such that the conveyance roller cannot be conveyed due to the insertion angle of the nip portion of the conveyance roller.

Therefore, in order to deal with the above, as shown in FIG. 6, there is provided a resist member arranged downstream of the sheet conveying means for preventing the sheet from advancing at the first position and releasing the block at the second position. There is disclosed an image forming apparatus provided with a sheet conveying unit configured to move from a first position to a second position mechanically interlocking with an optical scanning member of a document (Japanese Patent Publication No. 2-7462). (See the official gazette).

In FIG. 6, when the main switch is turned on, the document placing table 1 moves to the document exposing position, and when the copy button is pressed, the document placing table 1 starts moving to start the document exposure. The sheet is fed by sheet conveying rollers 7a and 7b, and when the leading edge of the sheet hits the registration 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. To 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 again transported toward the photoconductor 3 by the sheet transport rollers 7a and 7b. After the trailing edge of the sheet passes through the resist plate 32, the pin 20 moves 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, in the above technique, the original placing table is stopped with the resist plate lowered and the conveyance path opened due to a paper jam or the like, and the original placing table is returned to the home position. When a sheet is inserted when the sheet is re-started, the sheet is conveyed toward the photoconductor because the conveying roller is activated, and the timing may be shifted to cause miscopy.

In view of the above, according to the present invention, a sheet is inserted when the optical system scanning unit is stopped with the conveyance path opened and the optical system scanning unit is restarted without returning to the home position. Another object of the present invention is to provide an image forming apparatus capable of preventing the insertion of sheets and preventing miscopying.

[0008]

According to the present invention, there is provided an image forming section which visualizes an original image formed on a photosensitive member and then transfers the image onto a sheet, and a sheet from a sheet feeding port to a conveying path. In an image forming apparatus having a sheet conveying unit that conveys the sheet to the photoconductor along the conveying path, the leading end of the sheet conveyed along the conveying path is locked to temporarily hold the sheet in front of the photoreceptor. And a lock releasing means for releasing the locked state of the paper locked by the conveyance blocking portion at a predetermined timing to supply the paper to the photoconductor. Registers that are rotatable so as to have a blocking posture that locks the sheet to prevent the sheet from advancing and a blocking release state that releases the locked state of the sheet in the conveyance blocking section and guides the sheet to the photoconductor. A guide is provided, and the registration guide is fed in front of the paper transport unit in the blocking posture. A switch is provided that drives the paper transport unit by touching the paper inserted from the mouth, and does not touch the paper inserted from the paper feed port before the paper transport unit in the blocking release position and does not drive the paper transport unit. It has been done.

[0009]

In the above means for solving the problems, when the sheet is inserted, the resist guide is in the blocking posture, so that the sheet comes into contact with the switch to drive the sheet conveying section to convey the sheet to the photoconductor. Then, the leading edge of the sheet is locked by the conveyance blocking portion and the sheet is temporarily on standby in front of the photoconductor.

Then, at a predetermined timing, the registration guide is switched from the blocking posture to the blocking release posture in order to release the locked state of the paper locked in the conveyance blocking portion, and the paper is fed toward the photoconductor. When the leading edge of the paper reaches the photoconductor,
The switch does not contact the paper and the paper transport unit is not driven. At this time, when the optical system scanning unit is stopped and the optical system scanning unit is restarted without returning to the home position, even if the paper is inserted from the paper feed port, the paper does not contact the switch and the paper The conveyance section is left undriven, and the insertion of the sheet is blocked before the sheet conveyance section. Therefore, the sheet does not have to be conveyed toward the photoconductor by the sheet conveying section, and the timing is not shifted so that a miscopy does not occur.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 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 is reversely moved, and FIG. 3 is FIG. Front view showing the position of the switch in the state of
FIG. 4 is a view showing a state in which the optical system scanning unit is normally rotated and returned to the home position, and FIG. 5 is a front view showing a position of the switch in the state of FIG.

In the figure, reference numeral 50 denotes an apparatus main body, and 51 denotes an optical system for reciprocally moving forward and backward (left and right) on the apparatus main body 50 for optical scanning of an original to expose an original image on a photoconductor 52. A scanning unit, 53 is a sheet conveying unit that conveys a sheet to the photoconductor 52, 54 is an image forming unit that visualizes an original image formed on the photoconductor 52, and then transfers the sheet to the sheet, and 56 is transferred to the sheet. A fixing unit for fixing the toner image, which includes a sheet conveying unit 53, a photoconductor 52, and an image forming unit 5 in the apparatus main body 50.
4 and the fixing unit 56 are sequentially installed. Incidentally, reference numeral 57 in the figure denotes a carrying frame arranged along the carrying path, and 58.
Is a manual feed guide, and 59 is a paper feed port.

As shown in FIG. 1, the image forming section 54 is provided with a photosensitive member 5.
A charging charger, a developing device, a transfer charger, and a cleaner are sequentially arranged around the circumference of 2, and a document image is formed on the outer peripheral surface of the photoconductor 52 uniformly charged by the charging charger, and then the document image is formed. Is visualized as a toner image by a developing device, the toner image is transferred to a sheet by a transfer charger, and the residual toner is collected by a cleaner. The image forming unit 54 is supported by the image forming frame 54a. In the figure, reference numeral 55 does not show a transfer charger and other components of the image forming unit 54.

The fixing unit 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. The toner image transferred to is fixed. In this embodiment, the leading end of the sheet conveyed from the sheet conveying section 53 along the conveying path is locked,
The conveyance blocking unit 61 for temporarily holding the sheet in front of the photoconductor 52 and the locked state of the sheet locked by the conveyance blocking unit 61 are released at a predetermined timing to supply the sheet to the photoconductor 52. An unlocking means 62 is provided.

The conveyance blocking portion 61 is composed of a concave portion integrally provided on the conveyance frame 57 between the photoconductor 52 and the manual feed guide 58, and the side wall surface of the photoconductor 52 of the concave portion is engaged with the leading edge of the paper. It functions to stop the advance of the sheet and maintain the positional relationship between the sheet and the photoconductor 52, that is, to regulate the start position of the sheet. The unlocking means 62
Is disposed in the concave portion of the conveyance preventing portion 61, and when the optical system scanning portion 51 is reversed (moves leftward), the paper conveyance preventing portion 6 is conveyed.
1 and take a blocking posture to block the progress of the paper,
When the optical system scanning unit 51 is rotated in the normal direction (moved to the right), the registration is made rotatable so as to take a blocking release posture in which the paper is locked in the conveyance blocking unit 61 and guides the paper to the photoconductor 52. It comprises a guide 63 and a switching mechanism 64 for switching the resist guide 63 between a blocking posture and a blocking releasing posture according to the movement of the optical system scanning section 51.

The resist guide 63 is formed in a substantially U-shape in cross section so that the upper surface thereof serves as a sheet conveying surface to the photoconductor 52, and is provided upright from the bottom surface of the conveying preventing portion (recess) 61. It is supported by the support piece 80 via a horizontal shaft 81. Then, 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 before the paper transport unit 53 in the blocking posture as shown in FIGS. A micro switch 120 is provided which drives the transport unit 53 and does not contact the sheet inserted from the paper feed port 59 in front of the sheet transport unit 53 in the blocking release posture and does not drive the sheet transport unit 53. The micro switch 120 includes a switch main body 121 and a contactor 122 disposed on the switch main body 121 to contact the paper and sense the insertion of the paper. Then, the contact 122
Is tiltable in the sheet advancing direction as the sheet advances with respect to the switch body 121.

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 body 50, and a vicinity of the optical system scanning section 51 of the apparatus body 50. Is rotatably supported by the optical system scanning unit 51.
Of the first lever 90 during normal rotation of the first lever 90
Of the second lever 91 that restricts the rotation of the optical system scanning unit 51 and releases the contact with the first lever 90 to allow the rotation of the first lever 90 when the optical system scanning unit 51 rotates in the reverse direction. A connecting lever 92, which is connected to the other end and presses the resist guide 63 toward the blocking posture side, is provided in the optical system scanning unit 51, and the second lever 91 is provided when the optical system scanning unit 51 is reversed.
A lever contact body 93 for rotating the second lever 91 in the first lever contact releasing direction to release the pressing of the connecting lever 92 against the registration guide 63 on the blocking posture side.
And an urging spring 95 for urging the resist guide 63 toward the blocking release posture.
The posture of the resist guide 63 is switched mechanically in conjunction with 1.

The first lever 90 and the second lever 91
Are formed in a substantially V shape so that they face each other.
It is supported by support pieces 102 and 103 vertically provided 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.
Is fixed through.

The lever contact members 93 and 94 are arranged so as to correspond to the original image exposure distance of the optical system scanning unit 51. The biasing spring 95 is a coil spring, one end of which is mounted on the bottom surface of the recess 61 that controls the blocking member, and the other end of which is mounted on the lower surface of the resist guide 63. Further, the sheet conveying section 53 is composed of a driving roller 70 and a driven roller 71 which is pressed against the driving roller 70 from below and rotates following the driving roller 70. The rollers 70 and 71 sandwich the sheet. Transport. The drive roller 70 is rotatable about the horizontal axis 130, and the driven roller 71 is configured to rotate the driven roller 71 when the registration guide 63 takes the blocking posture.
It is rotatably supported by the registration guide 63 so as to be pressed against the drive roller 70 and rotated further than in the blocking posture. Incidentally, 131 in the figure is a paper guide.

In the above structure, when a sheet is inserted from the sheet feed port 59 through the manual feed guide 58 in the state shown in FIG.
Since the resist guide 63 is in the blocking posture, as shown in FIGS.
Contacting the contact 122 of the sheet feeding section 53, the driving roller 70 and the driven roller 71 of the sheet transporting section 53 are driven to move the sheet P to the photosensitive member 52.
To the side. Then, the leading edge of the sheet is conveyed to the conveyance blocking portion 6.
It is locked at 1, and its progress is blocked, and it stands by before the photoconductor 52. At this time, the optical system scanning unit 51, as shown in FIG.
Simultaneously with the driving of the driving roller 70 and the driven roller 71, the document is scanned in the reverse direction toward the left side for scanning the document, and when it is full left, it is moved toward the right side (forward rotation) as shown in FIG.

When the lever abutment body 93 provided on the scanning unit 51 comes into contact with the second lever 91 as the optical system scanning unit 51 moves toward the forward direction, the second lever 91 is rotated clockwise. Tilt to release the contact with the first lever 90. Then, the first lever 90 becomes free, and the pressing of the connecting lever 92 against the registration guide 63 is released. Along with this, the resist guide 63 moves the bias spring 95.
Due to the urging force of the above, it rotates upward and switches from the blocking posture to the blocking release posture. Therefore, the driving roller 70 and the driven roller 71
The sheet starts toward the photoconductor 52 by the driving force of. It should be noted that the driven roller 71 moves upward together with the switching of the blocking release posture of the registration guide 63, thereby increasing the pressure contact force with respect to the drive roller 70.

When the leading edge of the paper reaches the photoconductor 52, the contact of the paper to the contact 122 of the switch 120 disappears and the drive roller 70 and the driven roller 71 are not driven. At this time, the optical system scanning unit 51 is stopped due to a paper jam or the like, and when the optical system scanning unit 51 is restarted without returning to the home position, as shown in FIG. Even when it is inserted from 59, since the contact 122 of the switch 120 is located below the manual feed guide 58 as the blocking release posture of the registration guide 63 is switched, the leading edge of the paper P is placed on the contact 122. The driving roller 70 and the driven roller 71 are not driven and are not driven. Therefore, the sheet does not have to be conveyed toward the photoconductor 52 by the sheet conveying section 53, and the insertion of the sheet can be prevented before the sheet conveying section 53, so that the timing does not shift and miscopy does not occur.

When the document scanning is completed, the optical system scanning section 51 changes to the leftward (reverse) movement as shown in FIG. 2, and the lever abutment body 94 abuts against the first lever 90, and this is moved counterclockwise. Lean around. Accordingly, the connecting lever 92
Resists the urging force of the urging spring 95 and resist guide 63
Is rotated downward and pressed to switch from the blocking release posture to the blocking posture, the optical system scanning unit 51 returns to the home position, and the copy operation ends. At this time, the contactor 122 of the microswitch 120 is located at substantially the same position as the manual feed guide 58 along 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 drive roller 70 and the driven roller 71 are driven in contact with the leading edge of the paper P, and the paper P can be inserted.

Further, the transport blocking portion 61 is integrally formed with the transport frame 57 arranged along the transport path, and the transport blocking portion 61 locks the leading end of the paper to temporarily hold the paper 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, and compared with the conventional technology in which the start position of the paper is regulated by the resist plate. The variation 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 conveyance blocking unit 61 by the locking release means 62 is released at a predetermined timing and the paper is supplied to the photoconductor 52, the leading end position of the paper varies. Since it is not present, it is possible to prevent the position of the leading edge of the image on the sheet from being displaced.

Further, the lock releasing means 62 is the switching mechanism 6
4, the movement of the resist guide 63 is controlled by the optical system scanning unit 51.
Since it is mechanically linked with, the responsiveness of the resist guide 63 with respect to the movement of the optical system scanning section 51 is eliminated, and the sheet can be fed with a certain timing so as to correspond to the image position on the photoconductor. it can. Furthermore, in the paper transport section 53, the drive roller 7 of the driven roller 71 is
If the pressure contact force against 0 remains small, uneven feeding of the paper occurs, but the driven roller 71 is moved to the registration guide 63.
When the registration guide 63 is in the blocking posture, the registration guide 63 is pressed against the driving roller 70 and further rotated when the registration guide 63 is in the blocking posture. A strong pressure contact force is applied to the roller 71, so that the paper can be reliably conveyed without providing a pair of conveyance rollers between the conveyance prevention unit 61 and the photoconductor 52.

The present invention is not limited to the above embodiments, and it goes without saying that many changes or modifications can be made to the above embodiments within the scope of the present invention. For example, in the above-described embodiment, the same effect can be obtained even if the conveyance blocking portion is integrally formed with the image forming frame that supports the photoconductor, and the locking state of the sheet is released by the locking release means.

Further, the switching mechanism detects the forward / reverse movement of the optical system scanning section by the micro switch, and actuates the solenoid in accordance with the signal generated by the micro switch to move the guide member between the blocking position and the blocking releasing position. The configuration may be switched. Furthermore, in the above embodiment, the posture of the guide member is switched mechanically in conjunction with the optical system scanning unit,
The example in which the switching means is composed of the first lever, the second lever, the connecting lever, the lever abutment body and the biasing spring has been described, but in addition to this, the guide member is mechanically interlocked with the optical system scanning section. It suffices if the configuration is such that it can be switched to two positions of the blocking posture and the blocking release posture.

[0028]

As is apparent from the above description, according to the present invention, when the optical system scanning unit is stopped when the resist guide is in the blocking release posture, the optical system scanning unit is restarted without returning to the home position. Even if the paper is inserted from the paper feed port, the paper does not come into contact with the switch and the paper transport unit remains undriven, so the paper does not have to be transported toward the photoconductor by the paper transport unit. There is an excellent effect that it is possible to prevent the miscopying by blocking the insertion of the paper before the transport section.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a state in which an optical system scanning unit moves in a reverse direction.

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

FIG. 4 is a diagram showing a state in which the optical system scanning unit moves in the normal direction and returns to the home position.

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

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

[Explanation of symbols]

 51 Optical System Scanning Section 52 Photosensitive Member 53 Paper Conveying Section 59 Paper Feeding Port 61 Conveying Blocking Section 62 Lock Release Unit 63 Registration Guide 120 Switch 122 Contact

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H04N 1/00 108 H 4226-5C

Claims (1)

[Claims] 1. An image forming unit that visualizes a document image formed on a photoconductor and then transfers the image onto a sheet, and a sheet conveying unit that conveys the sheet from a paper feed port to the photoconductor along a conveying path. In the provided image forming apparatus, the leading end of the sheet conveyed along the conveying path is locked to hold the sheet temporarily in front of the photosensitive member, and the conveyance blocking section. Lock release means for releasing the locked state of the sheet at a predetermined timing to supply the sheet to the photoconductor is provided, and the lock release means locks the conveyance blocking section to block the advance of the sheet. The resist guide is provided with a rotatable rotation guide so as to have a blocking posture and a blocking release position in which the sheet is locked in the transport blocking section and is guided to the photosensitive member. The paper is conveyed by touching the paper inserted from the paper feed port before the paper transport section Drives the image forming apparatus characterized by switch not to drive the sheet conveying portion does not contact the paper that has been inserted from the paper feed port is provided in front of the sheet conveying portion during blocking release position.