JP4585698B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a document feeding device that feeds a document to an image reading position for reading a document image and then discharges the document. The An image forming apparatus such as a copying machine or a printer, which is provided in the apparatus main body and forms an image on a sheet based on image information read at a document reading position In Related.
[0002]
[Prior art]
Conventionally, a document feeder automatically feeds a document to an image reading position of an image reading device that reads the document. In many cases, the image reading apparatus is provided on the upper part of the main body of the image forming apparatus.
[0003]
Note that the manuscript includes not only a manuscript on which text is written but also a manuscript on which an image such as a character, a figure, or a picture is written on a sheet. In addition, the sheet includes plain paper, cardboard, and a thin sheet made of resin that is a substitute for plain paper.
[0004]
The image reading apparatus reads a document based on reflected light that is reflected by irradiating light onto the document conveyed on the platen glass. As an example of an image reading method, there is a so-called flow reading method in which an original is read by moving the original over a fixed light source. Therefore, the document feeder is required to allow the document to pass stably over the light source that is the image reading position.
[0005]
As a method for conveying an original, there is a method in which an original is pressed against a platen glass with a belt. In addition, there is a method in which a roller having a certain amount of static electricity and having a large inertia attracts a document by the static electricity and rotates and conveys the document. Further, there is a method in which a roller formed in a hollow shape and formed with a plurality of holes sucks the air in the roller, sucks the document, rotates it, and conveys it.
[0006]
However, in recent years, with a high-speed copy by a digital image forming apparatus combined with digital reading, memory storage, etc., in a transport-type document feeder that transports a document by a belt or the above roller, a belt, a roller, etc. It took a long time to stop, and it was difficult to cope with high-speed copying.
[0007]
Further, when the image reading apparatus reads a document on which images are formed on both sides, the document feeding apparatus must perform a reverse feeding operation of inverting the document and feeding it to the image reading position. When this reverse feeding operation is performed, the document feeder reverses the document by reversing the belt and rollers, so that it takes time to return to the normal conveyance speed after the belt and rollers are reversed. It was difficult to cope with the high speed of formation.
[0008]
In addition, the conveyance type document feeder that conveys the above belts, rollers, and the like is required to be compact as a unit and to reduce costs.
[0009]
For this reason, as a document feeder corresponding to a high-speed image forming apparatus, a conveyance unit is provided on each of the upstream side and the downstream side with respect to the image reading position so that the document can be delivered and the image reading position It is indispensable to have a configuration in which a restraining means such as a belt or a roller for firmly restraining the document or a document conveying means is not provided at a position opposite to the document.
[0010]
[Problems to be solved by the invention]
However, if the document feeder does not include the belt, roller, or other restraining means that presses the document at the image reading position, the document conveyance state at the image reading position becomes unstable, and the document being read vibrates. As a result, the image of the manuscript may be blurred.
[0011]
In particular, when the trailing edge of the document from the pair of conveying rollers on the upstream side of the image reading position comes off, image blur caused by vibration of the trailing edge of the document due to a separation shock, unevenness of the document transportation speed, or the like (more specifically, the present invention In this embodiment, which will be described with reference to FIG.
[0012]
Further, due to image blurring, there has been a problem that the reading of the original by the image reading device becomes inaccurate, and the image formed on the recording medium by the image forming device becomes a blurred image.
[0013]
In order to cope with this problem, as shown in FIG. 10, in the conventional document feeder, a mylar 50 is provided in the upper guide 7 a upstream from the image reading position 8, and the inside of the introduction path 7 is conveyed by this mylar 50. An incoming document is pressed against the platen glass 21 as close to the image reading position 8 as possible to prevent image blurring caused by vibration of the rear end of the document due to a release shock, unevenness in the document transport speed, or the like.
[0014]
However, when the mylar 50 or the like is used, when the document D comes into contact with another member and becomes jammed and stops near the mylar, when the user pulls out the document, the mylar 50 is turned up, It may be deformed. In such a case, the force of pressing the document of the mylar 50 is weakened, and the mylar 50 may not be able to reliably press the document against the platen glass 21.
[0015]
Further, when the document is being transported, dust such as toner printed on the document adheres to the platen glass 21, and in some cases, adheres to the image reading position 8 of the platen glass 21 to read the image. When a document read at position 8 is image-formed on a recording medium by the image forming apparatus, black streaks may enter the recording medium, which may deteriorate image quality.
[0016]
The present invention provides a document feeding device that allows a document to pass through a document reading position without causing vibration or unevenness in the document conveyance speed. The Image forming apparatus for accurately forming an image on a recording medium in a main body The It is intended to provide.
[0017]
[Means for Solving the Problems]
In order to achieve the above object, the present invention Image forming apparatus Is an image reading device that reads an image of a document conveyed on a platen glass at an image reading position. The image reading device can be opened and closed freely When assembled, send the document onto the platen glass With document feeder , Image forming means for forming an image on a sheet based on image information of a document read by the image reading device. And The document feeder is The introduction conveying unit that conveys the document to the image reading position from obliquely above to the image reading position, and the gap that allows passage of the document conveyed to the image reading position by the introduction conveying unit. Document guide means disposed opposite to the image reading position, and a document conveyance speed that is higher than the document conveyance speed of the introduction conveyance means when a document that has been read at the image reading position is received downstream of the document guide means And a document support guide unit having a document guide surface for guiding the document guided by the document guide unit to the discharge and transport unit, and the document support guide unit. The document feeder Vertical with respect to the main unit The document feeder is movably provided Said Assembled in an image reader In a closed state Then The lower part of the document support guide means is The image reading device A recess provided below the upper surface of the platen glass In contact with By preventing downward movement The upstream end side of the document guide surface is located below the platen glass, and the downstream end side of the document guide surface is a portion where the document guide means guides the document and a portion where the discharge conveyance means discharges the document. It is characterized in that it is positioned in the vicinity of an imaginary line connecting the two, and the conveyed document is guided to the discharge conveying means.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention And reference examples A document feeder and a copier equipped with the apparatus will be described with reference to the drawings.
[0025]
The document feeder can be installed not only in a copying machine but also in the main body of an image forming apparatus such as a printer. Therefore, the apparatus provided with the document feeder is not limited to a copying machine. In addition, this embodiment And reference examples The original feeding apparatus automatically supplies a plurality of originals continuously to the reading position, but can also supply them one by one manually by the user. Therefore, the document feeder is not limited to the automatic document feeder.
[0026]
(Copier)
FIG. 1 is a schematic front sectional view of a copying machine (image forming apparatus) 28.
[0027]
At the upper part of the copying machine main body 1, there is provided a document feeder 2 that conveys the document to the image reading position 8 and discharges it. The CPU 29 of the control means provided in the main body 1 of the copying machine 28 mirrors the reflected light obtained by irradiating the document passing through the image reading position 8 using the illumination system 13 according to the control program provided inside. 14, the image is recorded by projecting on an optical element (CCD or other element) 15 or a photoconductor.
[0028]
The photosensitive drum (image forming means) 16 is irradiated with light corresponding to the recorded document image to form a latent image. The latent image becomes a toner image by toner supplied from a toner supply device (not shown). The cassette 17 accommodates a recording medium (sheet) S such as paper or plastic film.
[0029]
A recording medium S is supplied from the cassette 17 between the photosensitive drum 16 and the transfer unit 18 in accordance with a recording signal from the CPU 29. On the recording medium S, the toner image formed on the photosensitive drum 16 is transferred by the transfer unit 18. Then, the recording medium onto which the toner image has been transferred is sent to the fixing device 19 to fix the toner image.
[0030]
When images are formed on both sides of the recording medium, the recording medium on which the image on one side is fixed by the fixing device 19 passes through the double-sided path 20 provided on the downstream side of the fixing device 19, and is turned upside down by a switchback conveyance path 32 on the way. Then, it is sent again between the photosensitive drum 16 and the transfer unit 18. As a result, the toner image is also transferred to the back surface of the recording medium. Finally, the toner image is fixed on the recording medium by the fixing device 19 and discharged to the outside.
[0031]
( Embodiment Original document feeder)
FIG. Embodiment 2 is a schematic front cross-sectional view of the document feeder 2 of FIG. FIG. 3 is an enlarged view of a main part of the document feeder 2.
[0032]
The document transport path around the image reading position is formed in a U-shape so as to shorten the length of the document feeder in the document transport direction, and guides the document diagonally from the upper side to the lower side of the image reading position 8. Thus, after the image reading position is guided, the image is guided obliquely upward.
[0033]
In FIG. 2, the document feeder 2 guides the document supplied from the document feeder 4 (see FIG. 1) through the introduction path 7 by introduction conveyance roller pairs (introduction conveyance means) 6a and 6b. It feeds to the reading position 8.
[0034]
A platen glass 21 is provided at the image reading position 8. Below the platen glass 21, an image reading unit (including an illumination system 13 and a mirror 14) ( Image reading device ) 33 is installed. Above the platen glass 21, a reading roller 22 (document guide means) is provided along a direction perpendicular to the document transport direction with a gap A between the platen glass 21 and the upper surface. The gap A is thick paper (basis weight, about 100 g / m) based on the experimental results. ² To about 150 g / m ² ) Is set to about 0.3 mm to about 0.5 mm. The numerical value of the gap A is not particularly limited, and it is needless to say that it can be appropriately set according to conditions such as the document conveyance speed and size, and the document thickness.
[0035]
The reading roller 22 rotates at substantially the same peripheral speed as the document conveyance speed so as not to cause resistance for document conveyance, but has a frictional resistance that does not become resistance for document conveyance. Does not have to rotate.
[0036]
Disposed on the downstream side of the image reading position 8 are a discharge path 9 that is bent with a predetermined curvature in the upper part of the figure, and a jump table 23 that is located at the entrance of the discharge path 9 and guides the document to the discharge path 9. ing. The discharge path 9 is provided with discharge conveyance roller pairs (discharge conveyance means) 10a and 10b.
[0037]
As shown in FIGS. 2 and 3, the document guide surface 23a of the jump table 23 guides the leading edge of the document that has passed through the gap A to a common tangent line (virtual line) B between the reading roller 22 and the discharge conveyance driving roller 10a. Inclined to do. The outer periphery of the reading roller 22 and the outer periphery of the discharge conveyance driving roller 10a are parts for guiding the document.
[0038]
Based on FIGS. 4 and 5, the drive configuration of each roller of the document feeder 2 will be described.
[0039]
The document feeder 2 is configured to drive each roller by a document supply motor M1 and a conveyance motor M2 that can freely rotate forward and backward. FIG. 4 is a diagram showing a drive transmission system on the document introduction side of the document supply motor M1. FIG. 5 is a diagram illustrating a drive transmission system on the document discharge side of the conveyance motor M2.
[0040]
In FIG. 4, the rotational force of the normal rotation of the document supply motor M1 is transmitted from the pulley P1 to each roller via the timing belt T1 and the pulley P2. The rotational force of the pulley P2 is transmitted in the order of the gear Z1, the gear Z2, and the gear Z3 attached to the drive shaft 34 of the document supply roller 4a. The document supply roller 4a rotates in the direction in which the document is supplied.
[0041]
A pulley P3 is also provided on the drive shaft 34 of the document supply roller 4a. The rotational force of the drive shaft 34 is also transmitted to the pickup roller 4b via a timing belt T2 stretched between the pulley P3 and the pulley P4 provided on the shaft 35 of the pickup roller 4b.
[0042]
One end side of a pair of elevating arms 4c and 4c that support the pickup roller 4b is attached to the drive shaft 34 of the document supply roller 4a. When the lift arms 4c and 4c are rotated by the rotation of the drive shaft 34 in the direction in which the document is supplied (the normal rotation drive of the document supply motor M1), the pickup roller 4b is lowered to contact the document. When the pickup roller 4b comes into contact with the document, the drive shaft 34 is idled with respect to the lifting arm 4c by the spring clutch X and the spring clutch Y.
[0043]
The registration drive roller 5a is connected to the motor M1 by a timing belt T3 stretched between a pulley P5 provided on the drive shaft 36 and a pulley P6 provided coaxially with the pulley P2. During normal rotation, the one-way clutch OW1 provided in the pulley P5 is prevented from rotating.
[0044]
The reverse rotation force of the document supply motor M1 is transmitted from the pulley P1 to the pulley P2 via the timing belt T1. The rotational force of the pulley P2 is transmitted from the pulley P6 provided coaxially with the pulley P2 to the pulley P5 attached to the drive shaft 36 of the registration drive roller 5a via the timing belt T3. As a result, the registration driving roller 5a rotates in the direction in which the document is supplied.
[0045]
At this time, the reverse rotation force of the document supply motor M1 is also transmitted to the drive shaft 34 of the document supply roller 4a. By the reverse rotation of the drive shaft 34, the elevating arm 4c rotates counterclockwise and raises the pickup roller 4b. Due to the reverse rotation of the drive shaft 34, the document supply roller 4a also attempts to reverse. However, the document supply roller 4a is not rotated by the one-way clutch OW2 provided inside the document supply roller 4a.
[0046]
The raised elevating arm 4c abuts against a regulating member (not shown) and is restricted from rotating. The drive shaft 34 is idled with respect to the lifting arm 4c by the spring clutch Z.
[0047]
In FIG. 5, the rotational force of the drive motor M2 is transmitted from the pulley P7 provided on the drive shaft 37 of the drive motor M2 to the pulley P8 via the timing belt T4. The rotational force transmitted to the pulley 8 is transmitted from the pulley P9 provided coaxially with the pulley P8 to the pulley P10 attached to the shaft 38 of the discharge conveyance drive roller 10a via the timing belt T6. As a result, the discharge conveyance drive roller 10a rotates forward or backward.
[0048]
Further, the rotational force transmitted to the pulley P10 is transmitted to the pulley P11 attached to the shaft 39 of the introduction conveyance drive roller 6a via the timing belt T7. As a result, the introduction conveyance drive roller 6a also rotates forward or backward.
[0049]
Further, the rotational force of the conveying motor M2 transmitted to the pulley P8 via the timing belt T4 is attached to the shaft 40 of the reverse drive roller 11a via the timing belt T5 from the pulley P12 provided coaxially with the pulley P8. Is transmitted to the pulley P13. As a result, the reverse driving roller 11a is also rotated forward or backward.
[0050]
Further, a pressure contact solenoid 30 is connected to the reverse driven roller 11b as a drive source for separating the reverse roller pair 11 in FIG. The pressure contact solenoid 30 presses the reverse driven roller 11b against the reverse drive roller 11a when excited (ON), and releases the pressure contact when the excitation is released (OFF). When the excitation of the press contact solenoid 30 is released, the reverse driven roller 11b is pulled by a spring (not shown) and moves away from the reverse drive roller 11a.
[0051]
Further, in the transport path for guiding the document, an empty sensor S1 that detects that the document is placed on the document placement unit 3, and the document that is transported between the feeding unit 4 and the registration roller pair 5. A registration sensor S2 that detects the edge of the document, a lead sensor S3 that is provided upstream of the image reading position 8 to detect the edge of the document, and a discharge sensor S4 that detects the edge of the document discharged from the image reading position 8. Are provided respectively.
[0052]
These sensors S1, S2, S3, and S4 are connected to a CPU 29 that controls driving of the entire apparatus. The CPU 29 controls the rotation of the motors M1 and M2 described above and the excitation control of the pressure contact solenoid 30 based on the detection signals from the sensors.
[0053]
An outline of the document conveying operation by the document feeder 2 when an image is formed on one side of the document will be described.
[0054]
Documents D are placed on the document placing unit 3 by the user, separated one by one by the feeding unit 4, and sequentially fed into the document feeding device 2. Subsequently, the document D is received by the registration roller pair 5 and temporarily stopped, a loop is formed, and the skew feeding is corrected. The document D whose skew has been corrected is introduced into the introduction path 7 when the registration roller pair 5 is started. Then, the document D is sent to the image reading position 8 by the introduction conveyance roller pair 6. As the document passes through the image reading position 8, the image formed on the surface of the document is read by the image reading unit 33. The document that has passed the image reading position 8 is sent through a discharge path 9 by a discharge conveyance roller pair 10 and discharged onto a discharge tray 12.
[0055]
An outline of the document conveying operation by the document feeder 2 when images are formed on both sides of the document will be described.
[0056]
First, as described above, when the document passes through the image reading position 8, an image on one side (front surface) is read. Thereafter, the original is transported through the discharge path 9 by the discharge transport roller pair 10 and is turned upside down by the switchback transport of the reverse roller pair 11. Then, the inverted document is sent again to the registration roller pair 5, and the skew is corrected by the registration roller pair 5 in the same manner as when reading the front surface. The document whose skew has been corrected passes through the introduction path 7 and the image formed on the front surface (in this case, the back surface) is read at the image reading position 8. Finally, the document passes through the discharge path 9 and is discharged onto the discharge tray 12.
[0057]
As described above, the document feeder 2 is configured to read the image of the document by the image reading unit 33 at the image reading position 8 by conveying the document in the direction of arrow C (see FIG. 2). In consideration of the stability of the document being conveyed, the reading roller 22 that does not act as a load when the document enters at the image reading position 8 prevents the conveyed document from being lifted. The flutter is suppressed. If the document conveyance speed by the introduction conveyance roller pair 6 is faster than the document conveyance speed by the discharge conveyance roller pair 10, there is a possibility that the document is slack inside the introduction path 7 and the discharge path 9. In this case, since it is impossible to suppress the shock due to the release of the slack, the document conveyance speed of the discharge conveyance roller pair 10 is usually slightly higher than the document conveyance speed of the introduction conveyance roller pair 6.
[0058]
However, when the document conveyance speed of the discharge conveyance roller pair 10 is slightly higher than the document conveyance speed of the introduction conveyance roller pair 6, the document D has the introduction conveyance roller pair 6 and the reading roller 22 as shown in FIG. The introduction path 7 and the discharge path 9 are conveyed along the upper side of the drawing between the discharge conveyance roller pair 10 in a tensioned state. However, when the trailing edge of the document D comes out of the introduction conveyance roller pair 6, the tensioned state of the document D is released as shown in FIG. Then, the document swells downward in the direction of the arrows of the introduction path 7 and the discharge path 9 due to its own weight and the elasticity of the document itself, and comes into contact with the lower surface. At this time, the portion of the document facing the image reading position 8 vibrates. In addition, the moving speed of that portion increases for a moment.
[0059]
Since the document receives only the conveying force of the discharge conveyance roller pair 10, it continues to be conveyed by the discharge conveyance roller pair 10. For this reason, the portion of the document D that swells downward approaches the common tangent line B. However, while the portion that bulges downward approaches the common tangent line B, the portion of the document that faces the image reading position 8 is temporarily stopped.
[0060]
Due to the vibration of the document and the unevenness of the document transport speed, the document is blurred and the image of the document is also blurred. This document blur causes reading of the reading unit 33 to be inaccurate and causes blurring of an image formed on a recording medium by a copying machine.
[0061]
Therefore, in the document feeder 2 of the present embodiment, the document guide surface 23a of the jump base 23 is a document that has passed through a gap A on a common tangent line B between the reading roller 22 and the discharge conveying drive roller 10a as shown in FIG. The document D is always supported at the position of the common tangent line B on the downstream end side of the document guide surface 23a.
[0062]
For this reason, the document D is supported by the jump table 23 even when the trailing edge of the document D comes out of the carry-in / conveying roller pair 6, and has conventionally occurred between the reading roller 22 and the discharge / conveying roller pair 10. The downward movement is prevented and no longer swells.
[0063]
Therefore, the document feeder 2 can minimize the separation shock of the document D, transport the document at a constant document transport speed, and prevent the document image from blurring at the image reading position 8. .
[0064]
The document guide surface 23a may have the same shape as the document guide surfaces 44a and 44b of the jump piece 44 described later. Further, the member denoted by reference numeral 51 in FIG. 10 of the conventional example does not guide the document at the position of the common tangent.
[0065]
Further, the jump table 23 may be incorporated in the platen glass 21 on the image forming apparatus main body side, but is preferably provided on the main body 46 side of the document feeder 2. Further, the jump table 23 may be fixedly provided on the main body 46 side of the document feeder 2, but as shown in FIG. 3, a slide shaft 48 projecting from the jump table 23 is used for document feeding. It is preferable that the main body 46 of the document feeder 2 is movably inserted into a vertically long slot 49 formed in a part of the apparatus.
[0066]
When the jump table 23 is provided on the main body 46 of the document feeder, the following advantages are produced as compared with the case where the jump table is provided on the platen glass 21.
[0067]
image In general, the reading apparatus can cope with the continuous reading of the image reading unit 33, and also supports so-called fixed reading in which the original is placed on the platen glass 21 and the illumination system 13 is moved to read the original. It has become. Therefore, if the platen glass is provided with a jumping base, when placing the document on the platen glass, the jumping base must be avoided. For this reason, the document placed on the platen glass is limited in size. Furthermore, when the image reading unit 33 reads a part of a large-size document, the document is placed on the platen glass so as to cover the jump table, and the document may be damaged by the jump table. However, if the jump table is provided in the main body of the document feeder, it is not necessary to avoid the jump table when placing the document on the platen glass. For this reason, the document placed on the platen glass is not limited in size. Furthermore, when the image reading unit 33 reads a part of a large-size document, the document can be placed on the platen glass without covering the jump table, and the document is not damaged by the jump table.
[0068]
Further, when the jump stand is movably provided on the main body of the document feeder, the following advantages are produced.
[0069]
Document feeder The platen is provided so as to be openable and closable with respect to the platen glass 21 so that the original can be placed on the platen glass and fixed reading can be supported. For this reason, if the jump table is movably provided in the main body of the document feeder, an error in the position of the jump table 23 attached to the document feeder 2 is absorbed, and the document feeder is brought into close contact with the platen glass 21. The image reading unit 33 can reliably read the original. The jump table 23 may be fixedly provided on the document feeder 2, but in this case, it is necessary to provide the jump table 23 at a position that does not hinder the adhesion of the document feeder 2 to the platen glass 21.
[0070]
In the above configuration, the original is not swollen by the jump table 23. However, in order to simplify the structure, instead of the jump table 23, as shown in FIG. A bulge of the document may be prevented by a jump piece 44 extending upstream along the common tangent line B at the upstream end of the guide 9a.
[0071]
The document guide surface 44a of the jump piece 44 is formed at substantially the same position as the common tangent line B connecting the reading roller 22 and the discharge conveyance driving roller 10a. Further, the document guide surface 44b at the upstream end of the jump piece 44 is inclined in a direction away from the common tangent line B so that the leading edge of the document can be easily guided to the document guide surface 44a.
[0072]
Further, instead of the reading roller 22, as shown in FIG. 8, a reading guide plate (original guide means) 47 having a small frictional resistance against the original may be provided. In this case, the common tangent line B is a straight line that passes through the downstream end 47a of the reading guide plate 47 and the outer periphery of the discharge conveyance driving roller 10a.
[0073]
( Reference example Original document feeder)
In FIG. Reference example FIG. 2 is a schematic front sectional view of the document feeder 41 of FIG.
[0074]
Reference example The document feeder 41 is provided with a fan 27 incorporated in the main body 46 of the document feeder 41 from an air outlet 26 formed in the vicinity of the jump base 45 disposed at the same position as the conventional entrance of the discharge path 9. Air is blown out to urge the document in the direction of the arrow in FIG. 9 so that it is along a common tangent line B connecting the reading roller 22 and the discharge transport driving roller 10a. The air discharge start time is set to a time just before the trailing edge of the original leaves the introduction conveyance roller pair 6. The air outlet 26 and the fan 27 constitute air blowing means.
[0075]
Therefore, Reference example The document feeder 41 is also Book Similarly to the document feeder 2 of the embodiment, the document is prevented from bulging between the reading roller 22 and the discharge conveyance roller pair 10, the separation shock of the document D is minimized, and the document is kept constant. The image is conveyed at the conveyance speed so that the image of the document does not blur with respect to the image reading position 8.
[0076]
Instead of the reading roller 22, a reading guide plate (original guide means) 47 having a low frictional resistance against the original may be provided as shown in FIG. In this case, the common tangent line B is a straight line that passes through the downstream end 47a of the reading guide plate 47 and the outer periphery of the discharge conveyance driving roller 10a.
[0077]
As described above, the document feeder 2 according to the present embodiment. And the reference document feeder 41 denotes the position of the document transport surfaces 23a and 44a of the jump table 23 and jump piece 44 provided at the entrance of the discharge path 9, and the discharge roller 22 (or the downstream end 47a of the read guide plate 47) and the discharge transport. By making the tangent line B connecting to the roller 10 equal to or slightly higher than the tangent line B, the trailing edge of the document is prevented from bulging when the introduction conveyance roller pair 6 is separated, and the trailing edge of the document is vibrated. Thus, unevenness in the document conveyance speed is prevented.
[0078]
Thereby, the document feeder 2 of the present embodiment. And the reference document feeder No. 41 can prevent image blurring of the document by minimizing shocks on the document at the image reading position 8 and unevenness in the conveyance speed of the document.
[0079]
Also, Book Document feeder 2 of embodiment And the reference document feeder Unlike the prior art, 41 does not use a mylar 50 (see FIG. 10) that suppresses shocks such as vibrations that occur in the original. Therefore, an original caused by turning over mylar during jam processing, which was caused by using the mylar. It is possible to eliminate uncertain pressing, scraping of toner printed on the document, and the like.
[0080]
further, Book Document feeder 2 of embodiment And the reference document feeder 41 uses a jump table 23, a jump piece 44, and a fan 27 to minimize the shock to the original and unevenness in the conveyance speed of the original to prevent the image blur of the original. By making the document transport path linear, it is possible to prevent image blurring of the document by minimizing unevenness of the document transport speed without using the jump table 23, the jump piece 44, and the fan 27. . However, if the document transport path is made linear, the length of the document feeder in the document transport direction becomes long, and if incorporated in the main body of the copier, there is a possibility that it will protrude from the main body of the copier. For this reason, Book Document feeder 2 of embodiment And the reference document feeder 41 is formed in a U-shape to shorten the length of the document feeder in the document conveyance direction, and guides the document from an obliquely upper side to an obliquely lower side of the image reading position, thereby guiding the image reading position. After that, it is a precondition that the vehicle is guided obliquely upward.
[0081]
Further, since the copying machine 28 of the present embodiment is provided with a document feeding device in the main body 1 that can reliably read an image by the image reading device, accurate information of the document can be obtained, and a recording medium can be obtained. An accurate image can be copied.
[0082]
【The invention's effect】
The document feeder according to the present invention can pass through the image reading position without causing vibration or unevenness in the document conveyance speed in the document, so that the image can be reliably read by the image reading device. .
[0083]
In addition, the document guide support means allows the image reading position to pass through the document without causing vibration or unevenness of the document conveyance speed, so that the previously used mylar is not used. Thus, it is possible to eliminate uncertainness of the document pressing due to the turning of the mylar during the jam processing and the scraping of the toner printed on the document.
[0084]
In addition, the air blowing means can pass through the image reading position without causing vibration or unevenness in the document conveyance speed even with the air blowing means. Thus, it is possible to eliminate uncertainness of the document pressing due to the turning of the mylar during the jam processing and the scraping of the toner printed on the document.
[Brief description of the drawings]
FIG. 1 is a schematic front sectional view of a copying machine which is an image forming apparatus according to an embodiment of the present invention.
FIG. 2 of the present invention Embodiment It is a partial schematic front sectional view of the document feeder.
FIG. 3 of the present invention Embodiment FIG. 2 is a schematic front sectional view of a main part of the document feeder of FIG.
FIG. 4 is a diagram illustrating a drive transmission system on a document introduction side of a document supply motor.
FIG. 5 is a diagram illustrating a drive transmission system on a document discharge side of a conveyance motor.
FIG. 6 is a diagram for explaining deformation of a document when the trailing end of the document has slipped out of the introduction conveyance roller pair in the document feeder.
FIG. 4A is a state diagram of a document before exiting an introduction conveyance roller pair.
FIG. 6B is a state diagram of a document that has passed through a pair of introduction conveyance rollers.
[Fig. 7] Of the present invention It is a figure of the modification of the original feeding apparatus of embodiment.
[Fig. 8] Of the present invention It is a figure of the modification of the original feeding apparatus of embodiment.
FIG. 9 Reference example FIG. 2 is a schematic front sectional view of the document feeder.
FIG. 10 is a schematic front sectional view of a conventional document feeder.
[Explanation of symbols]
A gap
B Common tangent (virtual line)
D Manuscript
S Recording medium (sheet)
1 Copying machine (image forming device) body
2,41 Document feeder
6 Introduction conveyance roller pair (introduction conveyance means)
8 Image reading position
10 Discharge transport roller pair (discharge transport means)
16 Photosensitive drum (image forming means)
22 Reading roller (document guide means)
23 Jump stand (document support guide means)
23a Document guide surface
26 Air outlet (air spraying means)
27 Fan (Air blowing means)
28 Copying machine (image forming device)
33 Image reader ( Image reading device )
44 Jump piece (document support guide means)
44a Document guide surface
46 Document Feeder Body
47 Reading guide plate (document guide means)

Claims (1)

An image reading device that reads an image of a document conveyed on the platen glass at an image reading position ;
It said image reading apparatus is assembled openably to a document feeding device for feeding a document to the platen on the glass,
An image forming apparatus comprising: an image forming unit that forms an image on a sheet based on image information of a document read by the image reading device ;
The document feeder is
Introducing and conveying means for conveying the document to the image reading position from obliquely upward to obliquely downward of the image reading position;
Document guide means disposed opposite to the image reading position through a gap allowing passage of the document conveyed to the image reading position by the introduction conveying means;
A discharge conveying unit that receives the document that has been read at the image reading position on the downstream side of the document guiding unit and discharges the document obliquely upward on the downstream side at a document conveying speed equal to or higher than the document conveying speed of the introduction conveying unit;
A document support guide unit having a document guide surface for guiding the document guided by the document guide unit to the discharge conveyance unit,
The document support guide means, with respect to the document feeding device main body is provided to be movable in the vertical direction, when the document feeder ing the closed state assembled to the image reading apparatus, wherein The lower part of the document support guide means abuts against a recess provided below the upper surface of the platen glass of the image reading device , and is prevented from moving downward, so that the upstream end side of the document guide surface is Located below the platen glass, the downstream end side of the document guide surface is positioned in the vicinity of a virtual line connecting a portion where the document guide means guides the document and a portion where the discharge conveyance means discharges the document, Guiding the document to be conveyed to the discharge conveying means;
An image forming apparatus .

Images