JP2005123890A - Image reader, and image recording processor using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reader capable of suppressing floating dusts from being carried to a reading position and preventing or suppressing occurrence of a streaky image. <P>SOLUTION: A lattice-shaped slit part 18a is opened in a reading entrance guide 18 arranged on an upstream side of a first reading conveyance part where a surface image of a document is read from below reading glass 21 in a document feeding direction. Dust (x) is dropped before dust (x) is taken to the reading position 20 by the conveyed original. A charging member 33 effective for dust collection of a minute object is fitted to a lower side being a back side of a feeding path of the slit part 18a. Not only dust (x) which naturally falls but dust (x) is drawn near by electrostatic force. Nonwoven fabric of permanent electro static charge can be used for the charging member 33. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image recording processing apparatus such as a copying machine, a facsimile machine, and a scanner, and an image reading apparatus used for document processing in the image recording processing apparatus.

  Some image reading apparatuses constituting a copying machine or the like have an image reading unit called a sheet-through method in which an image reading unit that stops an image reading unit and moves an original to read an image. In such a sheet-through type image reading unit, image defects due to the retention of foreign matter at the reading position is a serious problem. That is, adhesive materials such as re-peelable sticky notes (for example, Post-it (registered trademark)), glue on cut and pasted documents, inks and correction fluids that have not completely dried, erasers, or rubber debris on transport rollers and transport belts. When the document has just adhered to the reading position, or when dust, toner dust, or other floating substances such as dust do not adhere to the reading position, but are present at the reading position, the document is read at the same time. Thus, foreign matter may appear as streaks in the document transport direction in the read image.

  By the way, the sheet-through type image reading unit is often configured to include a reading glass for protecting the reading unit and for matching the original with the focal position of the reading unit. Further, such a reading glass is often used that has been subjected to a surface treatment such as a surfactant treatment or a conductive treatment so as to make it difficult for an adherent to adhere or a suspended matter to stay. However, it is not possible to completely prevent the adhesion of sticky materials and the retention of suspended matters as described above.

  In addition, the idea for preventing adhesion of sticky foreign matter to the reading position and staying of suspended matter is exclusive, and it is difficult to achieve at the same time. That is, in such a configuration, when the document is conveyed so that the document is brought into contact with the reading glass, the sticky substance as described above may adhere to the reading glass. Can be expected to be removed from. On the other hand, when the original is conveyed so that the original does not come into contact with the reading glass, the adhesive substance does not adhere to the reading glass, but it cannot be expected that floating substances are removed from the reading position by the original.

  Although it is relatively infrequent that the adhering material adheres to the reading unit, if it adheres, the streak image becomes very conspicuous. Also, it is relatively difficult to remove even after cleaning. On the other hand, when suspended matter stays in the reading unit, the streak of the image may not be so noticeable and can be removed relatively easily by cleaning, but the frequency of occurrence is relatively high. In any case, if you notice the occurrence of streak images after reading the image, you need to read the image again after cleaning and removing the stagnant matter that causes the streak. Is troublesome for the operator.

Conventionally, the adhesive glass and suspended matter are automatically cleaned by the operator, or by providing some cleaning means such as a cleaning member such as a brush or a scraper on the image reading device, or directing the airflow to the reading position, etc. In addition, for floating substances, a method has been proposed and implemented, such as providing an inclined part on the reading glass and dropping the floating substance on the lower part of the inclination.
Japanese Patent Laid-Open No. 11-305495 JP-A-10-210201 JP 11-146140 A

  However, when the size of an object becomes small, the force acting on the object is dominated by the adhesive force or electrostatic force proportional to the area (square of the dimension) rather than the inertial force proportional to the volume (the cube of the dimension). Due to the dimensional effect, paper dust and other floating objects are very small objects with a small size and mass, so they can be blown away by inertia force by applying physical force with a cleaning member or air current, A method of providing an inclined portion and sliding off from the reading position by gravity may not always be effective. In addition, another problem arises that the apparatus for that purpose becomes large-scale and the current reading section configuration must be changed significantly.

  Therefore, the present invention compares the retention of foreign matter at the reading position of the sheet-through type image reading unit with an effective method for a minute object in consideration of the above-described size effect and the current standard reading unit configuration. The purpose is to prevent or reduce the image by a method that can be easily mounted, and to prevent the generation of streak images due to the above-described causes.

  An image reading apparatus according to claim 1 of the present invention is a sheet-through type image reading apparatus in which a reading unit that reads a document image is stationary and a document to be read is moved to read the document image. A dust collecting means is arranged in the vicinity of the image reading position and upstream in the moving direction of the document.

  According to a second aspect of the present invention, in the image reading apparatus according to the first aspect, the dust collecting means uses a charging member.

  According to a third aspect of the present invention, in the image reading apparatus of the second aspect, a charging air filter is used as the charging member.

  According to the fourth aspect of the present invention, in a sheet-through type image reading apparatus that reads a document image by moving a document to be read by stopping a reading unit that reads the document image, in the vicinity of the image reading position of the reading unit. In addition, an opening leading to the outside of the image reading surface of the reading means is provided on the upstream side of the moving direction of the original, and a dust collecting means is disposed at a portion of the opening that is outside the image reading surface of the reading means. Features.

  According to a fifth aspect of the present invention, in the image reading apparatus according to the fourth aspect, the dust collecting means uses a charging member.

  According to a sixth aspect of the present invention, in the image reading apparatus of the fifth aspect, a charging air filter is used as the charging member.

  According to the seventh aspect of the present invention, in the image reading apparatus according to any one of the fourth to sixth aspects, the dust collecting means passes from the image reading surface of the reading means through the opening and goes out of the image reading surface of the reading means. It is a means for generating a flowing airflow.

  According to an eighth aspect of the present invention, in the image reading apparatus according to the seventh aspect, the means for generating the airflow uses a fan.

  An image recording processing apparatus according to claim 9 is characterized by using the image reading apparatus according to claims 1 to 8.

  The present invention can reduce floating dust from being brought to the reading position, and can prevent or reduce the generation of streak images.

  In addition, the present invention can be configured with an effective dust collection of a minute object and a safe and simple mechanism.

  The best mode for carrying out the present invention will be described below with reference to the embodiments shown in the drawings.

  FIG. 1 is a schematic sectional view showing an embodiment of an image recording processing apparatus for forming an image such as a copying machine using an image reading apparatus according to the present invention. The present invention relates to a general apparatus for conveying an image to be read whose image is to be read to a fixed reading device unit and reading an image while conveying the document at a predetermined speed. An example is an automatic document processing apparatus (hereinafter referred to as ADF) as an example. Of course, the present invention is not limited to this embodiment.

  The basic configuration, operation, and operation of this embodiment will be described with reference to FIG. 1 and control block diagrams (FIGS. 2 and 3). In the figure, A is a document setting unit for setting a document bundle to be read, B is a separation feeding unit for separating and feeding individual documents from the set document bundle, and C is a primary abutment of the fed document. A registration portion that serves to align and draw and convey a document after alignment, D is a turn portion that turns the conveyed document and conveys the document surface toward the reading side (downward), and E is a surface image of the document Is a first reading conveyance unit for reading from below the contact glass, F is a second reading conveyance unit for reading the back side image of the document after reading, and G is a discharge unit for discharging the document on which the front and back readings are completed to the outside of the apparatus. A paper unit H is a stack unit for stacking and holding originals after reading, and a control unit is a controller unit 100 for controlling a series of operations and a drive unit for driving a conveyance operation as shown in FIGS. 101-1 And a 5.

  The original bundle 1 for image reading is set on the original table 2 including the movable original table 3, and in this example, the original surface is set upward. Further, the width direction of the document bundle 1 is positioned in a direction perpendicular to the conveyance direction by a side guide (not shown). The document set is detected by the set filler 4 and the set sensor 5 and transmitted to the main body control unit 111 by the I / F 107. Further, as the document length detection sensors 30 and 31 provided on the document table surface, a reflection type sensor or an actuator type sensor that can detect even one document is used. Determine. That is, a sensor arrangement that can determine at least whether the document size is vertical or horizontal is necessary.

  The movable document table 3 is configured to move up and down in the directions of arrows a and b shown in the figure by a bottom plate raising motor 105. When the set filler 4 and the set sensor 5 detect that a document is set, the bottom plate raising motor 105 is moved. The movable document table 3 is raised so that the uppermost surface of the document bundle 1 comes into contact with the pickup roller 7 by rotating 105 forward. The pickup roller 7 is operated by the pickup motor 101 in the directions indicated by arrows c and d by the cam mechanism, and the movable table 3 is lifted and pushed by the upper surface of the document on the movable table 3 to rise in the arrow c direction. The upper limit can be detected by the rise detection sensor 8.

  When the print key is pressed down from the main body operation unit 108 and a document feed signal is transmitted from the main body control unit 111 to the DF control unit 100 via the I / F 107, the pickup roller 7 is rotated by the forward rotation of the paper feed motor 102. Is rotated to pick up several (ideally one) originals on the original table 2. The rotation direction is a direction in which the uppermost document is conveyed to the sheet feeding port. The paper feeding belt 9 is driven in the paper feeding direction by the normal rotation of the paper feeding motor 102, and the reverse roller 10 is driven to rotate in the reverse direction to the paper feeding by the normal rotation of the paper feeding motor 102, and the uppermost document and the document under it. Are separated, and only the uppermost document can be fed.

  More specifically, the reverse roller 10 is in contact with the paper feeding belt 9 at a predetermined pressure, and when the paper is in direct contact with the paper feeding belt 9 or in contact with one sheet of original, the reverse roller 10 rotates. Therefore, when the document is rotated counterclockwise and two or more originals enter between the sheet feeding belt 9 and the reverse roller 10, the rotation force is set to be lower than the torque of the torque limiter. The reverse roller 10 rotates in the clockwise direction, which is the original driving direction, and pushes back an excess document, thereby preventing double feeding. The document separated into one sheet by the action of the paper feeding belt 9 and the reverse roller 10 is further fed by the paper feeding belt 9, the leading edge is detected by the abutting sensor 11, and the pull-out roller 12 is further stopped. I hit it. Thereafter, the sheet feeding motor 102 is stopped in a state where it is sent by a predetermined distance from the detection of the butting sensor 11 and as a result is pressed against the pull-out roller 12 with a predetermined amount of bending. As a result, the driving of the paper feeding belt 9 is stopped.

  At this time, when the pickup roller 7 detects the abutting sensor 11, the pickup roller 7 rotates the pickup motor 101 to retract the pickup roller 7 from the upper surface of the document, and sends the document only by the conveying force of the paper feed belt.

  By such an operation, the leading edge of the document enters the nip of the pair of upper and lower rollers of the pull-out roller 12, and the leading edge is aligned (skew correction). The pull-out roller 12 has a skew correction function, and is a roller for transporting a skew-corrected document to the intermediate roller 14 after separation, and is driven by a reverse rotation of the paper feed motor 102. At this time, that is, when the paper feed motor 102 rotates in reverse, the pull-out roller 12 and the intermediate roller 14 are driven, but the pickup roller 7 and the paper feed belt 9 are not driven. A plurality of document width sensors 13 are arranged in the depth direction and detect the size in the width direction perpendicular to the conveyance direction of the document conveyed by the pull-out roller 12. Further, the length of the document in the conveying direction is detected from the motor pulse by reading the leading edge and the trailing edge of the document with the butting sensor 11.

  When the document is transported from the resist section C to the turn section D by driving the pull-out roller 12 and the intermediate roller 14, the transport speed at the resist section C is set higher than the transport speed at the read transport section E. Thus, the processing time for sending the document to the reading unit is shortened. When the leading edge of the document is detected by the reading entrance sensor 15, deceleration is started at the same time as the document feeding speed is set to the same speed as the reading conveyance speed before the leading edge of the document enters the nip between the upper and lower rollers of the reading inlet roller 16. The reading motor 103 is driven to rotate forward to drive the reading inlet roller 16, the reading outlet roller 23, and the CIS outlet roller 27.

  When the registration sensor 17 detects the leading edge of the document, the registration sensor 17 decelerates over a predetermined conveyance distance, temporarily stops before the reading position 20, and transmits a registration stop signal to the main body control unit 111 via the I / F 107. Subsequently, when a reading start signal is received from the main body control unit 111, the document whose registration has been stopped is transported at an increased speed so as to rise to a predetermined transport speed before the leading end of the document reaches the reading position. At the timing when the leading edge of the document detected by the pulse count of the reading motor reaches the reading unit, the gate signal indicating the effective image area in the sub-scanning direction on the first surface is sent to the main body control unit 111 by the first reading unit. Sent until is removed.

  In the case of single-sided document reading, the document that has passed through the reading conveyance unit E is conveyed to the paper discharge unit G through the second reading unit F. At this time, when the leading edge of the original is detected by the paper discharge sensor 24, the paper discharge motor 104 is driven to rotate forward to rotate the paper discharge roller 28 counterclockwise. In addition, the discharge motor pulse count from the detection of the leading edge of the document by the discharge sensor 24 reduces the discharge motor drive speed immediately before the trailing edge of the document comes out of the nip of the pair of upper and lower rollers of the discharge roller 28 to discharge the document. Control is performed so that the document discharged onto the tray 29 does not jump out. In the case of double-sided document reading, DF control is performed on the second reading unit 25 when the document leading edge reaches the second reading unit 25 by the pulse count of the reading motor after the discharge sensor 24 detects the document leading end. A gate signal indicating an effective image area in the sub-scanning direction is transmitted from the unit 100 until the trailing edge of the original passes through the reading unit. The second reading roller 26 serves as a reference white part for obtaining shading data in the second reading unit as well as suppressing the floating of the original in the second reading unit.

  The second reading unit 25 includes a light source unit 200, a sensor chip 201, an amplifier 202, an A / D converter 203, an image processing unit 204, a frame memory 205, an output control circuit 206, and an I / F circuit 207.

  The following configuration will be described in detail. First, a conventional guide configuration upstream of the reading position in the ADF as described above will be described with reference to a cross-sectional view shown in FIG. As shown in FIG. 4, the original is conveyed by the reading entrance roller 16 in the reading section E, and is read by a reading means (not shown) below the reading glass 21 while being conveyed on the reading entrance guide 18 and the reading glass 21. At position 20, the image plane is read. The reading roller 19 and the reading guide plate 32 regulate the behavior of the document in the floating direction so that the document being read does not float.

  FIG. 5 is a sectional view showing a configuration example according to the first embodiment of the present invention. The reading entrance guide 18 is provided with a lattice-shaped slit portion 18a for dropping the dust x before the dust x is brought into the reading position 20 by the conveyed document. The opening width of the slit portion 18a may be set as appropriate in the document conveyance direction and its intersecting direction. The dust x that has naturally dropped by the slit portion 18a escapes to the outside of the image reading surface, specifically to the lower side, and is not brought into the reading position 20 (A). However, since there is not much dust x falling naturally, in the present invention, as shown in (B), a minute amount is formed on the lower surface side of the slit portion 18a of the reading inlet guide 18 on the back side with respect to the conveyance path. A charging member 33 effective for collecting the object is attached so that the dust x is attracted not only by the naturally falling dust x but also by electrostatic force. As the charging member 33, for example, a permanently charged non-woven fabric such as that used in recent air filters and masks can be used. These are highly available and can form a dust collecting mechanism relatively easily and inexpensively. Of course, other charging materials may be used.

  FIG. 6 shows a second embodiment according to the present invention. In this example, a flow path 34 is provided on the back side of the slit portion 18, and dust x is attracted to the slit portion 18 a by sucking air by the intake fan 35. It is simply discharged. If a general small intake fan or the like is used as the fan 35, the dust collection mechanism can be configured with high availability and relatively easily and inexpensively. In this example, the duct 36 constituting the flow path 34 is provided below the inlet guide 18, but of course, a special duct may not be provided if air flows in the machine.

  FIG. 7 shows a third embodiment according to the present invention. In this example, the case where the electrostatic force or the airflow alone has a weak force to attract the dust x and the dust collection effect is insufficient is considered. That is, it is configured to include a charging member 33a having air permeability, a flow path 34, and a fan 35, and the dust collection effect is further enhanced by the dust collection effect by intake air and the dust collection effect by electrostatic force. The charging member 33a and the fan 35 are the same as in the previous embodiment.

1 is a schematic cross-sectional view showing an embodiment of an image recording processing apparatus for forming an image such as a copying machine using an image reading apparatus according to the present invention. Control block diagram of the apparatus of FIG. Control block diagram of the apparatus of FIG. Sectional drawing which shows the guide structure of the conventional reading position upstream in the apparatus of FIG. Sectional drawing which shows the structural example which concerns on 1st Example of this invention. Sectional drawing which shows the structural example which concerns on 2nd Example of this invention. Sectional drawing which shows the structural example which concerns on 3rd Example of this invention.

Explanation of symbols

A: Document setting unit B: Separation feeding unit C: Registration unit D: Turn unit E: First reading conveyance unit F: Second reading conveyance unit G: Paper discharge unit H: Stack unit 1: Document bundle 2: Document table 2: Document table 3: movable document table 4: set filler 5: set sensor 7: pickup roller 8: table lift detection sensor 9: paper feed belt 10: reverse roller 11: abutment sensor 12: pull-out roller 13: document width sensor 14: intermediate roller 15: Reading entrance sensor 16: Reading entrance roller 17: Registration sensor 18: Reading entrance guide 18a: Slit portion 18b: Louver 19: Reading roller 20: Reading position 21: Reading glass 23: Reading exit roller 24: Paper discharge sensor 25: Second reading unit 27: CIS exit roller 28: paper discharge roller 29: paper discharge tray 30, 3 : Document length detection sensor 32: Reading guide plates 33 and 33a: Charging member 34: Flow path 35: Air intake fan 36: Duct 100: DF control unit 101: Pickup motor 102: Paper feed motor 103: Reading motor 104: Paper discharge Motor 105: Bottom plate raising motor 107: I / F
108: main body operation unit 111: main body control unit 200: light source unit 201: sensor chip 202: amplifier 203: A / D converter 204: image processing unit 205: frame memory 206: output control circuit 207: I / F circuit x: dust

Claims (9)

In a sheet-through type image reading apparatus in which a reading unit that reads an original image is stationary and an original to be read is moved to read the original image, in the vicinity of the image reading position of the reading unit and on the upstream side in the moving direction of the original An image reading apparatus comprising dust collecting means. 2. The image reading apparatus according to claim 1, wherein the dust collecting means uses a charging member. 3. The image reading apparatus according to claim 2, wherein a charging air filter is used as the charging member. In a sheet-through type image reading apparatus in which a reading unit that reads an original image is stationary and an original to be read is moved to read the original image, in the vicinity of the image reading position of the reading unit and on the upstream side in the moving direction of the original An image reading apparatus comprising: an opening communicating with an outside of the image reading surface of the reading unit; and a dust collecting unit disposed on a portion of the opening that is outside the image reading surface of the reading unit. 5. The image reading apparatus according to claim 4, wherein the dust collecting means uses a charging member. 6. The image reading apparatus according to claim 5, wherein a charging air filter is used as the charging member. 7. The image reading apparatus according to claim 4, wherein the dust collecting unit is a unit that generates an airflow that flows from the image reading surface of the reading unit through the opening and flows outside the image reading surface of the reading unit. An image reading apparatus characterized by the above. 8. The image reading apparatus according to claim 7, wherein the means for generating the airflow uses a fan. An image recording processing apparatus comprising the image reading apparatus according to claim 1.

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