JP2007119113A - Paper feeding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To retain a balance of paper feeding force and separation resistance without troublesome user operation and to prevent failure of paper feeding when the loading number of paper sheets is varied and when various paper sheets with different thickness and rigidity are fed in a paper feeding device of low cost and small size. <P>SOLUTION: The paper feeding device is provided with a means for detecting total thickness of the paper loaded on a paper loading means of the paper feeding device and a means for detecting the kind of the paper. The optimum drive control condition is led out based on the paper total thickness detection result and the paper kind detection result and drive control of the separation paper feeding means is varied. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to stability of sheet feeding performance of a sheet feeding device that stacks and holds sheets and supplies them to a recording unit such as a printer and a reading unit such as a scanner.

  Many image recording devices and image reading devices include a paper feeding device. The sheet feeding device includes a sheet stacking unit that stacks a plurality of sheet materials such as recording and reading sheets, a sheet feeding unit that conveys the stacked sheets to a recording unit and a reading unit, and a plurality of sheets Separating means for separating so that only one sheet is conveyed.

  The paper feeding means is usually composed of a rubber roller, and abuts against the surface of the stacked paper with a predetermined pressing force to rotate, thereby generating a paper feeding force and transporting the paper.

  On the other hand, there are various types of separation means. The separation means includes a bank, a claw, a separation roller, or the like, and performs separation by applying resistance to other sheets so that only the uppermost sheet is not fed.

  At this time, if the paper feeding force is too small with respect to the resistance of the separating means, no paper is fed, and if the paper feeding force is too large, a plurality of papers are fed at once. This will cause a double feed error. In addition, when the balance between the sheet feeding force and the separation resistance is different between the left and right sides of the sheet, the sheet is obliquely fed obliquely, causing a paper jam error and reducing the quality of recording and reading.

  In order to perform a stable paper feeding operation in this way, it is important to stabilize the paper feeding force applied to the paper against the paper separation resistance. It changes depending on the pressing force with the paper. The pressing force of the paper feed rubber roller is often obtained by urging either the paper feed rubber roller or the paper stacking means against the other with a spring or the like, but the pressing force due to the spring bias varies depending on the number of sheets stacked. For this reason, the variation in the sheet feeding force increases. Also, in a paper feeding device that urges either the paper feed rubber roller or the paper stacking means with respect to the other, the variation in paper feed force and separation resistance also varies depending on the rotation angle depending on the number of sheets stacked. growing. Furthermore, since the friction coefficient between the paper feed rubber roller and the paper surface changes depending on the smoothness of the paper surface, the paper feed force varies greatly depending on the paper type. Separation resistance also varies depending on the thickness and rigidity per sheet.

As means for stabilizing the paper feeding performance of such a paper feeding device, using a motor, a solenoid, or the like, the urging force for either one of the paper feeding rubber roller or the paper stacking means can be varied to vary the paper feeding power variation. The form to reduce (for example, refer patent document 1) etc. are disclosed.
Japanese Patent Laid-Open No. 05-105254

  However, since these conventional techniques are provided with a drive source such as a motor or a solenoid, there are problems that the apparatus cost increases and the apparatus size increases. In addition, the means for deriving the optimum urging force for each type of paper is paper setting by user operation, or when paper is not detected by the paper sensor provided downstream in the paper feeding direction, non-delivery due to insufficient urging force Since it is a method of judging an error, there is a problem that a paper feed failure occurs due to a user's setting mistake, or that an optimal biasing force cannot be set unless a non-feed error occurs once. .

  Accordingly, an object of the present invention is to provide a sheet feeding force without complicated user operation even when various types of sheets having different sheet load, thickness, and rigidity are fed in a low-cost and small-sized sheet feeding device. The purpose of this is to maintain a balance between the separation resistance and the feeding failure.

  In order to achieve the above object, a sheet feeding device according to the present invention includes a separation sheet feeding unit and a drive control unit for the separation sheet feeding unit, and loads sheets from a sheet stacking unit that stacks and holds a plurality of sheets. A sheet feeding device that conveys one sheet at a time, comprising sheet total thickness detecting means for detecting the total thickness of sheets stacked on the sheet stacking means, and separating sheet feeding means based on the detection result of the sheet total thickness detecting means The drive control is changed.

  The sheet feeding device according to the present invention includes a separation sheet feeding unit and a drive control unit for the separation sheet feeding unit, and feeds sheets one by one from a sheet stacking unit that stacks and holds a plurality of sheets. An apparatus comprising: a paper type detection unit that detects a type of paper stacked on the paper stacking unit; and a drive control of the separation paper feeding unit is changed based on a detection result of the paper type detection unit. To do.

  The sheet feeding device according to the present invention includes a separation sheet feeding unit and a drive control unit for the separation sheet feeding unit, and feeds sheets one by one from a sheet stacking unit that stacks and holds a plurality of sheets. An apparatus comprising: a total sheet thickness detecting unit that detects a total thickness of sheets stacked on the sheet stacking unit; and a sheet type detecting unit that detects a type of sheets stacked on the sheet stacking unit, The drive control of the separation sheet feeding unit is changed based on the detection results of the total sheet thickness detection unit and the sheet type detection unit.

  According to such a configuration, the sheet feeding device according to the present invention changes the drive control of the separation sheet feeding unit according to the total thickness of the sheets stacked on the sheet stacking unit, so even when the sheet loading amount changes. It is possible to stably perform the paper feeding operation while maintaining a balance between the paper feeding force and the separation resistance.

  In addition, since the paper feeding device according to the present invention changes the drive control of the separation paper feeding unit according to the type of paper loaded on the paper stacking unit, even when feeding various types of paper having different thickness and rigidity. It is possible to stably perform the paper feeding operation while maintaining a balance between the paper feeding force and the separation resistance.

  In addition, since the sheet feeding device according to the present invention changes the drive control of the separation sheet feeding unit according to both the total thickness and the type of sheets loaded on the sheet loading unit, the sheet type changes in addition to the sheet loading amount. Even in such a case, it is possible to maintain a balance between the sheet feeding force and the separation resistance and perform the sheet feeding operation stably.

  Since the total paper thickness detection and the paper type detection are performed in a state where the paper is stacked on the paper stacking means, it is possible to derive the optimum drive control condition before the paper feeding operation is started and regardless of the user setting. , Paper feeding failure can be prevented in advance.

  As described above, by providing the paper feeding device according to the present invention in an image recording device, an image reading device, and an image reading and recording device, there is no image recording error or image reading error due to poor paper feeding, and an easy-to-use device. Can be provided to the user.

Example 1
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a recording apparatus including a paper feeding device according to an embodiment of the present invention.

  The recording apparatus 1 includes a recording unit 3 that records characters and images on the sheet material 2, a sheet feeding unit 4 that feeds the sheet material 2 to the recording unit 3, and a sheet fed from the sheet feeding unit 4. A transport unit 5 that transports the material 2 to the recording unit 3 and a control board 10 that controls the operation of the mechanism of each unit are provided.

  The sheet feeding unit 4 includes a sheet material stacking unit 6 on which a plurality of sheet materials 2 are stacked, a separation sheet feeding mechanism 7 that separates the sheet material 2 from the sheet material stacking unit 6 one by one, and the separated sheet feeding. And a drive mechanism (not shown) for driving the mechanism 7.

  In the sheet material stacking section 6, a plurality of sheet materials 2 are stacked on a pressure plate 16 that is rotatably attached to the base 15. The pressure plate 16 is attached so as to be inclined with respect to the apparatus installation horizontal plane. Since the sheet material 2 mounted on the sheet material stacking unit 6 is stacked in an inclined state, the sheet material 2 is biased downward by gravity, and its front end is fixedly provided on the base 15. Has been hit.

  The pressure plate 16 has a rotation center R in the vicinity of the upper end, is urged toward the paper feed roller 11 by a pressure plate spring 17, and is regulated by a control cam included in a drive mechanism (not shown). That is, when the control cam releases the restriction, the pressure plate 16 is urged to rotate clockwise in the drawing by the pressure plate spring 17, and the uppermost surface of the stacked sheet material 2 comes into contact with the paper feed roller 11. Next, the sheet feeding roller 11 in contact with the uppermost surface of the sheet material 2 rotates clockwise in the drawing, so that a sheet feeding force is applied to the sheet material 2. On the other hand, when the control cam engages with the pressure plate 16, the pressure plate 16 is rotated counterclockwise in the drawing and separated from the paper feed roller 11.

  Next, the total sheet thickness detecting unit and the sheet type detecting unit according to the present embodiment will be described with reference to FIG.

  Above the pressure plate 16, a sensor arm 24 on which a total sheet thickness detecting unit 26 and a sheet type detecting unit 25 are mounted is provided.

  The total sheet thickness detection means 26 includes an optical encoder mounted on the sensor arm 24 and an optical scale held on the base 15, and detects a rotation angle until the sensor arm 24 contacts the surface of the sheet material 2. By doing so, the total thickness of the sheet material 2 stacked on the pressure plate 16 is detected. On the other hand, the paper type detection means 25 includes a light source LED, a light sensor, and a photoelectric conversion element at the tip of the sensor arm 24, detects the amount of light reflected on the surface of the sheet material 2, and stores it in a memory provided on the control board 10. The paper type is determined by collating with the reflected light amount data for each held paper type.

  When a recording command is sent to the recording apparatus 1, the total thickness and type of the sheet material 2 stacked on the pressure plate 16 are detected prior to paper feeding. That is, the sensor arm 24 rotates counterclockwise in FIG. 3 so that the tip abuts against the surface of the sheet material 2, and the total sheet thickness detection unit 26 detects the total sheet thickness and the sheet type detection unit 25 detects the sheet type. Is called. Thereafter, the sensor arm 24 rotates clockwise and is separated from the surface of the sheet material 2, so that the sheet feeding operation is not hindered.

  The control circuit mounted on the control board 10 selects the drive control condition of the drive mechanism based on the detected total sheet thickness and sheet type.

  For example, when the total sheet thickness detecting unit 26 detects that the sheet material 2 is thick, the amount of rotation of the pressure plate 16 from the separated state until the uppermost surface of the sheet material 2 comes into contact with the sheet feeding roller 11 is small. For this reason, the spring force of the pressure plate spring 17 is strong. That is, since the sheet feeding force applied to the sheet material 2 is large, the sheet material 2 is likely to be fed, and extremely speaking, a double feed error is likely to occur. In such a case, the control circuit sets the drive control conditions to prevent double feed errors by setting the current and voltage applied to the motor that is the drive source to a low value or setting the motor speed to a low value. Select.

  On the contrary, when the total sheet thickness detecting unit 26 detects that the stacked thickness of the sheet material 2 is small, the rotation amount of the pressure plate 16 from the separated state until the uppermost surface of the sheet material 2 contacts the sheet feeding roller 11 is determined. Since there are many, the spring force of the pressure plate spring 17 is weak. That is, since the sheet feeding force applied to the sheet material 2 is small, the sheet material 2 is difficult to be fed, and in an extreme case, a non-feed error is likely to occur. In such a case, the control circuit sets the current and voltage applied to the motor as a drive source to a high value, sets the motor rotation speed to a low value, or causes the paper feed roller 11 to contact the surface of the sheet material 2. Drive control conditions are selected so as to prevent a non-transmission error by setting a long time from contact to start of rotation.

  When the total sheet thickness detecting unit 26 detects that the stacked thickness of the sheet material 2 is small and the sheet type detecting unit 25 detects that the sheet material 2 is thick paper such as glossy paper, And the resistance of the separation paper feeding mechanism 7 is increased, so that a non-feed error is more likely to occur. Even in such a case, the control circuit selects the drive control condition so as to prevent the non-transmission error.

  Since the drive mechanism including the paper feed roller 11 is driven based on the drive control condition selected in this way, the paper stacking amount changes or various papers having different thicknesses and rigidity are fed. However, the balance between the sheet feeding force applied to the sheet material 2 and the separation resistance is always maintained, and the occurrence of sheet feeding defects such as double feeding error, non-feeding error, and skew feeding is prevented, and stable feeding operation is performed. be able to. In addition, since the paper feeding device derives the optimum drive control condition before the paper feeding operation is started and without depending on the user setting, it is possible to prevent paper feeding failure.

  In the present embodiment, the paper feeding device that urges the pressure plate 16 against the paper feeding roller 11 by the spring force of the pressure plate spring 17 has been described as an example. However, as shown in Patent Document 1, a motor, a solenoid, or the like is used. In the sheet feeding device in which the urging force of the pressure plate 16 with respect to the sheet feeding roller 11 is variable, driving conditions such as the motor and solenoid are selected based on the detection results of the sheet total thickness detecting means and the sheet type detecting means. And an optimal biasing force may be applied. For example, if it is determined that a double feed error is likely to occur based on the detection result of the total sheet thickness detection means or the paper type detection means, the biasing force is weakened. On the other hand, if it is determined that a non-feed error is likely to occur, the biasing force is By strengthening the sheet strength, the balance between the sheet feeding force applied to the sheet material 2 and the separation resistance is always maintained, and the occurrence of sheet feeding defects such as double feeding errors, non-feeding errors, and skew feeding can be prevented.

  In this embodiment, the paper feeding apparatus having both the total paper thickness detecting means and the paper type detecting means has been described as an example. However, either the total paper thickness detecting means or the paper type detecting means is used. The same effect can be obtained in the paper feeder provided with only the above. That is, in a paper feeding device having only the total paper thickness detecting means, it is possible to prevent a paper feeding failure such as a double feed error, a non-feed error, and skew feeding when the paper stacking amount changes. Alternatively, in a paper feeder equipped with only paper type detection means, when feeding various types of paper with different thicknesses and rigidity, it is possible to prevent the occurrence of paper feed defects such as double feed error, non-feed error, and skew feeding. it can.

(Example 2)
Below, 2nd embodiment which concerns on this invention is described using FIG. The paper feeding device in this embodiment includes only the paper total thickness detecting means. The total paper thickness detecting means 26 includes an optical scale that is integrally attached to the pressure plate 16 and an optical encoder that is held by the base 15.

  When a recording command is sent to the recording apparatus 1, the restriction by the control cam is released, the pressure plate 16 is urged to rotate clockwise in the figure, and the uppermost surface of the stacked sheet material 2 is brought into contact with the sheet feeding roller 11. Touch. At this time, the rotation angle of the pressure plate 16 from the separated state is detected by the total sheet thickness detecting means 26, and the total thickness of the sheet material 2 is detected. The control circuit selects the drive control condition of the drive mechanism based on the detected total sheet thickness as in the case of the first embodiment described above.

  According to the present embodiment, even in a lower-cost and small-sized paper feeding device, the balance between the paper feeding force applied to the sheet material 2 and the separation resistance is always maintained even when the paper stacking amount changes. It is possible to prevent the occurrence of paper feed defects such as double feed error, non-feed error, and skew feeding.

1 is a cross-sectional view of a recording apparatus including a paper feeding device according to an embodiment of the present invention. FIG. 4 is a detailed view of a total sheet thickness detecting unit and a sheet type detecting unit of the sheet feeding device according to the embodiment of the present invention. FIG. 6 is a detailed view of a total sheet thickness detecting unit of a sheet feeding device according to a second embodiment of the present invention.

Explanation of symbols

2 Sheet material 3 Recording unit 4 Paper feed unit 5 Transport unit 6 Sheet material stacking unit 7 Separation paper feed mechanism 10 Control board 11 Paper feed roller 15 Base 16 Pressure plate 17 Pressure plate spring 24 Sensor arm 25 Paper type detection means 26 Paper total thickness detection means

Claims (3)

  A sheet feeding device that includes a separation sheet feeding unit and a drive control unit for the separation sheet feeding unit, and conveys the sheets one by one from a sheet stacking unit that stacks and holds a plurality of sheets. A sheet feeding device comprising sheet total thickness detecting means for detecting the total thickness of stacked sheets, and changing drive control of the separation sheet feeding means based on a detection result of the sheet total thickness detecting means.   A sheet feeding device that includes a separation sheet feeding unit and a drive control unit for the separation sheet feeding unit, and conveys the sheets one by one from a sheet stacking unit that stacks and holds a plurality of sheets. A sheet feeding device comprising sheet type detection means for detecting the type of stacked sheets, and changing drive control of the separation sheet feeding means based on a detection result of the sheet type detection means.   A sheet feeding device that includes a separation sheet feeding unit and a drive control unit for the separation sheet feeding unit, and conveys the sheets one by one from a sheet stacking unit that stacks and holds a plurality of sheets. A total sheet thickness detecting unit for detecting the total thickness of the stacked sheets, and a sheet type detecting unit for detecting the type of the sheets stacked on the sheet stacking unit, the total sheet thickness detecting unit and the sheet type detecting unit The sheet feeding device is characterized in that the drive control of the separation sheet feeding means is changed based on the detection result.

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