JPH0566632A - Image forming device - Google Patents

Abstract

PURPOSE:To stop an optical scanning part when a resist guide is in a restraining release attitude and to prevent inserting of paper preventing copying error even when the paper is inserted when the optical scanning part is started again without being returned to a home position. CONSTITUTION:When the paper is inserted, it is carried to a photosensitive body 52 side by a paper carrying part 53. At this time, a restraining attitude is taken by the resist guide 63, and the leading tip of the paper is restrained by a carrying restraining part 61, and the paper is made to temporarily standby before the photosensitive body 52. Then, the resist guide 63 is changed over from the retraining attitude to the restraining release attitude to release the restrained state of the paper restrained to the carrying restraining part 61 at a specified timing and the paper is fed toward the photosensitive body 52. At this time, a carrying path extending from a feeding opening 59 of the paper to the paper carrying part 53 is shut off by a shut off part 120 of the resist guide 63 along with the changing over of the restraining release attitude, and the insertion of the paper is restraining.

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. 8, there is provided a resist member arranged downstream of the sheet conveying means for preventing the advance of the sheet 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. 8, 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 and starts 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, when the document placing table lowers the resist plate and stops at the position where the conveyance path is opened due to a paper jam or the like, the document placing table is returned to the home position. If the sheet is inserted when the sheet is restarted without doing so, the sheet may be conveyed toward the photoconductor due to the conveyance roller being activated, and the timing may be shifted to cause miscopy.

In view of the above, according to the present invention, even if 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, the paper is inserted. An 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 inserted from the paper feed port of the paper in the blocking release posture. In which blocking unit for blocking the conveying path to the sheet conveying portion is provided.

[0009]

In the above means for solving problems, when a sheet is inserted, it is conveyed to the photosensitive member side by the sheet conveying section. At this time, since the registration guide is in the blocking posture, the leading edge of the sheet is locked by the conveyance blocking section and the sheet is temporarily waiting 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. At this time, even if a sheet is inserted when the optical system scanning unit is stopped and is restarted without returning the optical system scanning unit to the home position, the blocking unit of the registration guide is accompanied by the switching of the blocking release posture. Since the conveyance path from the paper feed port to the paper conveyance unit is blocked, the insertion of the paper is prevented before the paper conveyance unit. Therefore, the sheet does not have to be conveyed toward the photoconductor by the sheet conveying section, and the timing does not shift so that a miscopy does not occur.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An 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 front view of a relevant part, and FIG. 3 is a plan view of a relevant part.
FIG. 4 is a diagram showing a state in which the optical system scanning unit moves in the reverse direction,
FIG. 5 is a front view showing the position of the blocking portion in the state of FIG. 4,
FIG. 6 is a diagram showing a state in which the optical system scanning unit is normally rotated and returned to the home position, and FIG. 7 is a front view showing the position of the blocking unit 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 section 56 is provided with 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 provided integrally with 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.

As shown in FIGS. 2 and 3, 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 the conveying preventing portion (concave portion) 61. It is supported via a horizontal shaft 81 by a support piece 80 which is erected from the bottom surface of the. At the front end of the registration guide 63 (the end portion on the manual feed guide 58 side), as shown in FIGS. 6 and 7, a blocking unit 120 that blocks the transport path from the paper feed port 59 to the paper transport unit 53 in the blocking release posture. Is provided. The blocking portion 120 is a plate-shaped member and is integrally formed with the resist guide 63. And the blocking unit 6
As shown in FIGS. 4 and 5, when the registration guide 63 is in the blocking posture, the paper is fed from the paper feed port 59 to the paper transport unit 53.
A through hole 121 is formed for passing through (see FIGS. 5 and 7).

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 a vicinity of the optical system scanning section 51 of the apparatus main 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, 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. As shown in FIG. 3, one end of the drive roller 70 is rotatable about a horizontal axis 131 supported by a support piece 130 provided upright from the registration guide 63. The driven roller 71 is connected to the registration guide 63. Is rotatably supported by the registration guide 63 so that when the registration guide 63 takes the prevention posture, the registration guide 63 is pressed against the drive roller 70 and rotated further than in the prevention posture. In the figure, 132 is a bearing and 133 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.
The driving roller 70 and the driven roller 71 are driven. At this time, since the registration guide 63 is in the blocking posture,
As shown in FIGS. 4 and 5, the paper P passes through the through hole 121 of the blocking unit 120 of the resist guide 63 and is conveyed to the photoconductor 52 side. Then, the leading edge of the sheet is locked by the conveyance blocking unit 61, its progress is blocked, and the sheet stands by before the photoconductor 52.
At this time, as shown in FIG. 4, the optical system scanning unit 51 is driven to rotate the driving roller 70 and the driven roller 71, and at the same time, the optical system scanning unit 51 is moved in the reverse direction toward the left side for scanning the original, and when the left side is full, the scanning is performed.
As shown, move to the right (normal rotation).

Then, as shown in FIG. 6, the optical system scanning section 51
When the lever abutment body 93 provided on the scanning unit 51 abuts the second lever 91 in accordance with the forward movement of the second lever 91, the second lever 91 is tilted clockwise and abuts against the first lever 90. To cancel. 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 registration guide 63 is rotated upward by the urging force of the urging spring 95 to switch from the blocking posture to the blocking release posture. Therefore, the sheet starts toward the photoconductor 52 by the driving force of the driving roller 70 and the driven roller 71. At this time, the through hole 121 of the blocking unit 120 is located below the manual feed guide 58 according to the blocking posture of the registration guide 63, as shown in FIG.
Since it is not in communication with the paper feed port 5
9 to the paper transport unit 53 (driving roller 70, driven roller 7
The transport route to 1) is blocked. The driven roller 7
1 moves up together with the switching of the blocking release posture of the registration guide 63, thereby increasing the pressure contact force to the drive roller 70.

When the document scanning is completed, the optical system scanning section 51 changes to the leftward (reverse) movement as shown in FIG. 4, 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, and the next sheet P can be inserted. After that, the optical system scanning unit 51 returns to the home position and the copy operation ends.

As described above, when the resist guide 63 is in the posture of releasing the blocking, the sheet feeding port 59 of the sheet is formed by the blocking section 120.
Since the conveyance path from the sheet conveyance unit to the sheet conveyance unit 53 is cut off, the optical system scanning unit 51 is stopped when the resist guide 63 is in the blocking release posture due to a paper jam or the like, and the optical system scanning unit 51 is returned to the home position. Even if a sheet is inserted when the sheet is restarted without any action, the blocking section 120 of the registration guide 63 prevents the sheet from being inserted in front of the sheet conveying section 53. Therefore, the paper is conveyed by the paper conveyance unit 53 to the photoconductor 52.
Since it does not have to be transported toward the sheet, there is no chance of mis-copying due to timing deviation.

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 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, and the start position of the paper is determined by the positional accuracy of the transport frame with respect to the photoconductor. Therefore, as compared with the related art in which the start position of the paper is regulated by the resist plate, it is possible to suppress variation in the positional relationship between the photoconductor and the start position of the paper and accurately hold the same. 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 embodiment, if the upper portion of the blocking portion of the registration guide is located below the manual feed guide in the blocking posture to allow the passage of the sheet, the blocking portion has a through hole for passing the sheet. It may not be formed.

Further, the same effect can be obtained even if the conveyance blocking portion is integrally formed with the image forming frame for supporting the photoconductor and the locked state of the paper is released by the locking release means. Further, the switching mechanism is configured to detect forward / reverse movements of the optical system scanning unit with a micro switch and operate a solenoid in response to a signal generated by the micro switch to switch the guide member between two positions of a blocking posture and a blocking release posture. Good.

Furthermore, in the above embodiment, the switching means is the first lever, the second lever, the connecting lever, and the lever abutment body so as to mechanically interlock with the optical system scanning section to switch the posture of the guide member. Also, an example in which the biasing spring is used has been described, but other than this, a structure that mechanically interlocks with the optical system scanning unit to switch the guide member between two positions of a blocking posture and a blocking releasing posture may be used.

[0028]

As is apparent from the above description, according to the present invention, when the resist guide is in the blocking release position, the conveying path from the sheet feeding port to the sheet conveying section is cut off by the blocking section. Even when a sheet is inserted when the system scanning unit is stopped when the resist guide is in the blocking release posture and is restarted without returning the optical system scanning unit to the home position, it is possible to prevent the sheet insertion. Therefore,
There is an excellent effect that the timing is not shifted and a miscopy does not occur.

[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 front view of the same main portion.

FIG. 3 is a plan view of the same main part.

FIG. 4 is a diagram showing a state in which the optical system scanning unit moves in the reverse direction.

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

FIG. 6 is a diagram showing a state when the optical system scanning unit moves in the normal direction and returns to the home position.

FIG. 7 is a front view showing the position of the blocking portion in the state of FIG.

FIG. 8 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 Blocking Section

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. A blocking guide is provided, and a registration guide that is rotatable so as to take a blocking release state of the transport blocking unit and guide the sheet to the photoconductor is provided in the blocking guide. Occasionally, a blocking unit is installed to block the transport path from the paper feed port to the paper transport unit. An image forming apparatus characterized by being.