JP2005338685A - Document size detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the probability of erroneous detection of a document size detection device caused by an operation habit of a user, as a result of switching a document cover to an automatic document feeder from a platen cover. <P>SOLUTION: The document size detection device uses an opening/closing detection means for outputting a continuous value matching an angle at which the document cover is opened/closed. Based upon the output of the opening/closing detection means, a document size judgement means judges a document size. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a document size detection device used in a copying machine, a facsimile, a scanner, and the like, and more particularly to a document size detection device that detects the size of a document placed on a platen glass.

  In general, an image reading apparatus, a copying machine, or the like has a function of automatically detecting an original size and performing image reading and image formation conforming to the original size. Or a desired operation | work can be performed only by mounting on platen glass. That is, in the copying machine, there is no need for the operator to select a recording sheet, and the machine automatically selects a recording sheet suitable for the document size and performs copying.

  A document reading device having a function of reading a document by conveying the document to a reading position by an automatic document feeder and a function of reading a document placed on a platen glass is generally used. Therefore, there is a need for a document size detection device that detects the size of a document to be conveyed and a document size detection device that detects the size of a document placed on a platen glass.

  In the document size detection device that detects the size of the document placed on the platen glass, the document size is detected in the operation of opening the document cover, placing the document on the platen glass, and closing the document cover. Therefore, it is not desirable to impose a special operation on the operator for detecting the document size. In addition, a method of performing a pre-scan for document size detection prior to a main scan of a document is not desirable because the total time required for document reading becomes long.

  For this reason, a technique for detecting the document size in the process of closing the document cover has been developed and put into practical use.

  FIG. 1 shows a typical example of the prior art for detecting the size of a document on a platen glass.

  The document 2 is placed on the platen glass 3 with the document cover 1 opened, and then the document cover 1 is closed and the document is read.

  In the process of closing the document cover 1, the open / close detection means SB detects the closing operation of the document cover 1, and at the timing when this detection signal is received, the document size determination means 4 reads the outputs of the document size detection means SA1 and SA2, Determine the document size. The open / close detection means includes a switch that is turned on / off when the document cover is closed to a certain angle.

  The document size determination unit 4 reads the outputs of the document size detection units SA1 and SA2 and determines the document size at the timing when the signal of the open / close detection unit SC that detects that the document cover 1 is completely closed is received.

  The document size determination performed at the detection timing of the opening / closing detection unit SB is mainly determination for a blank document, and the document size determination performed at the detection timing of the opening / closing detection unit SC is determination for a color paper document.

  Reading of the document size detection means SA1 and SA2 is on / off reading, and the document size is determined based on whether each document size detection means is on or off.

  However, since the opening / closing operation of the document cover is not constant and varies in the opening / closing speed, the handling of the document cover, etc., there is a problem that an error occurs in the on / off timing of the opening / closing detection means SB, and erroneous detection occurs. Technology to prevent false detection has been developed.

  In Patent Document 1, an error is detected by detecting the document size based on a signal that detects the bending of the document cover, a signal that the document cover is opened at a predetermined angle, and a signal from the document size detection unit. It has been proposed to prevent detection.

Japanese Patent Application Laid-Open No. 2004-228620 proposes detecting the document size based on a signal that detects the document size based on a closing operation signal of the document cover and a document size detection signal at the start of copying.
JP-A-10-221788 JP-A-9-243331

  The conventional technique for detecting the size of a document on the platen glass is unsatisfactory because the probability of erroneous detection cannot be sufficiently reduced.

  This is mainly due to an error in the operation of the open / close detection means SB in FIG. 1 that determines the document size detection timing. In particular, when a platen cover having only a document holding function is switched to an automatic document feeder as a document cover, a detection error occurs due to a difference in the operation timing of the open / close detection means SB.

  Further, erroneous detection occurs due to the slow speed of the opening and closing operation of the document cover. That is, based on the operation timing of the opening / closing detection means SB, the output of the document size detection means SA1 and SA2 is read after a predetermined time from the operation timing, but the document size detection means is different depending on whether the closing operation is slow or fast. A difference occurs in the level of the detection signal, and erroneous detection is performed. The probability of erroneous detection further increases due to the combination of the operation error of the open / close detection means SB and the slow operation of the document cover.

  Such a problem cannot be solved by Patent Documents 1 and 2.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems in the prior art for detecting the document size of a document placed on a platen glass, and to provide a document size detection device with a very low probability of erroneous detection. Objective.

The object of the present invention is achieved by the following invention.
1.
Platen glass on which the document is placed,
A document cover that is rotatably supported in the vicinity of one end of the platen glass and is movable to an open state that opens the platen glass and a closed state that covers the platen glass,
A document size detecting means having a light emitting element for irradiating a document and a light receiving element for receiving reflected light from the document, and disposed below the platen glass;
An open / close detecting means for detecting an open / close angle of the document cover and outputting a change in the open / close angle as a continuous value; and
A document size determination unit that reads an output of the document size detection unit and determines a document size when the document cover is closed to a predetermined angle from the output of the opening / closing detection unit;
A document size detecting device having
The document size determination means is detected based on an output level Lmax of the opening / closing detection means when the document cover is completely opened and an output level Lmin of the opening / closing detection means when the document cover is completely closed. A document size detection apparatus that determines timing and executes at least one document size detection.
2.
2. The document size detection according to claim 1, wherein the document size determination unit performs the document size detection when an output of the open / close detection unit reaches a predetermined value between the output levels Lmax and Lmin. apparatus.
3.
Platen glass on which the document is placed,
A document cover that is rotatably supported in the vicinity of one end of the platen glass and is movable to an open state that opens the platen glass and a closed state that covers the platen glass,
A document size detecting means having a light emitting element for irradiating a document and a light receiving element for receiving reflected light from the document, and disposed below the platen glass;
An open / close detection means for detecting an open / close angle of the document cover and outputting a change in the open / close angle as a continuous value; and
A document size determination unit that reads an output of the document size detection unit and determines a document size when the document cover is closed to a predetermined angle from the output of the opening / closing detection unit;
A document size detecting device having
The document size detecting means has a plurality of sensors arranged at different distances from a rotation axis for opening and closing the document cover,
The document size detection device, wherein the document size determination means executes at least one document size detection at a timing set based on a high / low switching timing of one output of the plurality of sensors.
4).
4. The timing according to claim 3, wherein the set timing is a timing at which the opening / closing detection means outputs a level higher than a level of output by the opening / closing detection means corresponding to the high / low switching timing. Document size detection device.
5).
5. The document size detection apparatus according to 3 or 4, wherein the high / low switching timing is a high / low switching timing on the most open side of the document cover among outputs of the plurality of sensors.
6).
When the output level Lmax of the opening / closing detection means when the document cover is fully opened and the output level Lmin of the opening / closing detection means when the document cover is completely closed,
5. The document size detection apparatus according to item 4, wherein the predetermined value is a value between Lmax and Lmin.
7).
7. The document size detection apparatus according to any one of claims 1 to 6, wherein the document size determination unit executes another document size detection in a state where the document cover is almost completely closed.
8).
7. The document size detection apparatus according to 2 or 6, further comprising a storage unit that stores information of the predetermined value.
9.
9. The document size detection apparatus according to 8, wherein the information is rewritable.

  According to the invention described in any one of claims 1 to 9, erroneous detection of the document size due to a deviation of the document size detection timing caused by the detection error of the opening / closing of the document cover by the opening / closing detection means is satisfactorily prevented. .

  According to the first, second, or sixth aspect of the present invention, the detection is performed by removing the offset error due to the difference in the angle detection of the open / close detection means between the platen cover having no document conveying function and the automatic document conveying device. Size detection errors that are likely to occur when replacing the automatic document feeder are extremely small.

  According to the invention of claim 3, 4 or 5, the high / low switching of the original document size detecting means and the high / low switching of the original size detecting means by the original cover are reliably separated and detected. The probability of occurrence of false detection can be made extremely low.

  According to the sixth aspect of the invention, the sizes of the blank original and the colored original can be reliably and accurately detected.

  According to the seventh or eighth aspect of the invention, it is possible to set the performance of the document size detecting device to the maximum during the manufacturing process, installation of the device, maintenance, and the like.

  FIG. 2 is a diagram showing a figure document size detection apparatus according to the embodiment of the present invention.

Reference numeral 1 denotes a document cover. In the illustrated example, a platen cover having only a document suppressing function and not having a document conveying function is used. However, an automatic document conveying device may be used.
The document holding cover 1 is supported at the right end by the image forming apparatus so that it can be opened and closed by rotation. Reference numeral 3 denotes a platen glass, and the document 2 is placed on the platen glass 3. SA1 and SA2 constitute a document size detecting means, which is a sensor composed of a light emitting element that irradiates the document, which is composed of LEDs, and a light receiving element, which is composed of a phototransistor and that receives reflected light from the document. In the figure, two sensors are shown, but several sensors for detecting the document size in the vertical and horizontal directions are provided. A line sensor that detects the length of the document can also be used. Reference numeral 4 denotes a document size determination unit composed of a CPU, which controls the entire document size detection device and performs size detection. Reference numeral 5 denotes storage means composed of a nonvolatile memory, which stores information on the timing of document size detection described later. Reference numeral 6 denotes an operation unit. An operation for instructing the storage unit 5 to write the timing information is performed from the operation unit 6.

  Reference numeral SB denotes an open / close detecting means for detecting opening / closing of the document cover, and includes a disk-shaped sliding resistor 7, an electrode 8 that contacts the sliding resistor 7, an actuator 9 that moves up and down by opening / closing the document cover 1, and an actuator 9. The lever 10 is connected and rotates in conjunction with the upper and lower sides of the actuator 9.

  The sliding resistor 7 is integrated with the lever 10, and the sliding resistor 7 rotates according to the opening / closing angle of the document cover 1, and the rotation angle of the sliding resistor 7 is detected by the electrode 8, and is continuously The value is output.

  In copying, the document cover 1 is opened, the document 2 is placed on the platen glass 3, and the document cover 1 is closed, whereby document scanning means (not shown) scans the document 2 and reads the document image. The document scanning means is a well-known device that moves along the platen glass 3 while irradiating the document 2 to scan the document and read an image.

  FIG. 3 shows the operation of the document size detection apparatus according to Embodiment 1 of the present invention. In the figure, w indicates the output of the open / close detection means SB, x indicates the output of the sensor SA1, and y indicates the output of the sensor SA2. As shown in the figure, the open / close detection means SB outputs the maximum level Lmax in a state where the document cover 1 is fully opened, and continuously decreases as the document cover 1 is closed, thereby completely closing the document cover 1. The lowest level Lmin is output in the state.

  The sensors SA1 and SA2 are at a low level because the reflected light of the irradiated light does not enter the sensors SA1 and SA2 when the document cover 1 is open, and are parallel to the platen glass 3 in the process of closing the document cover 1. When the position is close to, the document cover 1 is irradiated and the reflected light enters the sensors SA1 and SA2, and the outputs of the sensors SA1 and SA2 are switched from the low level to the high level. When the document cover 1 is not completely parallel to the platen glass 3, the distance between the document cover 1 and the platen glass 3 varies depending on the distance from the rotation axis 1 a of the document cover 1. The sensor SA1 and the sensor SA2 have different high / low switching timings as shown in the figure.

  When detecting the document 2 on the platen glass 3, the sensors SA1 and SA2 receive reflected light from the document and output a high level as indicated by a dotted line. In the illustrated example, the document 2 is detected as indicated by the dotted line by the sansa SA1 and the document is not detected by the SA2. As described above, the presence or absence of the document 2 is detected by reading the outputs of the sensors SA1 and SA2 at the timing when the reflected light from the document cover 2 is not received, and the document size is detected by reading the outputs of the plurality of sensors. The

  In the figure, two sensors are shown. However, a plurality of sensors are arranged in parallel in the vertical and horizontal directions of the original, and an actual used original such as an A series, a B series, an inch series, or an irregular size is used. All sizes can be detected.

  The document size determination unit 4 reads the outputs of the sensors SA1 and SA2 at timings T1 and T2, and performs document size detection.

  Timing T1 is the detection timing of a blank document, and outputs high level when there is a document and low level when there is no document, from sensors SA1 and SA2. Timing T2 is a detection timing of a colored paper document, and outputs a low level when the document is present and a high level when the document is absent.

  Accordingly, the document determination means 4 performs document size detection at timing T1 and document size detection at timing T2 by the opposite logic processing.

  Timing T1 is when the output of the opening / closing detection means SB reaches a predetermined first level L1, and timing T2 is when the opening / closing detection means SB reaches a predetermined second level L2.

  The first level L1 and the second level L2 are set as a percentage smaller than 100, where the highest level Lmax−the lowest level Lmin is 100. That is, the levels L1 and L2 are set to values that fall between Lmax and Lmin. L1 is preferably an intermediate value between Lmax and Lmin, and L2 is preferably a value close to Lmin. Both predetermined values are set to values at which the timings T1 and T2 are sufficiently separated from the high and low switching points T3 and T4 of the sensors SA1 and SA2.

  Since the predetermined levels L1 and L2 are relative values set using the maximum level Lmax and the minimum level Lmin in this way, errors due to differences in individual characteristics of the document size detection device, differences in installation conditions, and the like. It is extremely small, and the probability of erroneous size detection can be made extremely low.

  In particular, the timing T1 for detecting the size of the most common blank document in the past has been highly variable due to the characteristics of individual document size detection devices and installation conditions, and erroneous determination is likely to occur. Such misdetection is often caused when the platen cover and the automatic document feeder are replaced. Between the output of the open / close detecting means SB at the time of the platen cover and the output of the open / close detecting means SB at the time of the automatic document feeder. This is due to an offset error that produces a certain output difference. The detection method described above can satisfactorily prevent erroneous determination represented by an offset error.

  Information on the predetermined levels L1 and L2 is stored in the storage means 5. The information stored in the storage means 5 is set by adjustment at the time of factory shipment of the apparatus, and then installed at the operation position of the apparatus, for example, when the document cover is switched from the platen cover to the automatic document feeder, maintenance is performed. It is rewritten to the optimum value at the time of service call.

  FIG. 4 shows a case where erroneous detection occurs due to the characteristics and installation conditions of the document size detection apparatus. FIG. 4 shows an example in which the document size is detected after the output of the document size detection sensor SA1 is reversed because the timing T1 approaches the timings T3 and T4. In this example, the document cover 1 is closed by the closing operation. It is erroneously determined that the reversal of the original document size detection means SA1 to the high level is due to document detection.

  In this embodiment, such erroneous detection is well prevented.

  FIG. 5 shows the operation of the document size detection apparatus according to Embodiment 2 of the present invention. In the figure, the level L3 of the output of the document opening / closing detection means SB is a value at the high / low switching timing T3 when the output of the sensor SA1 is switched from the low level to the high level.

  The timing T1 for detecting the size of the blank original is set to the timing when the output of the open / close detection means SB becomes a level L4 higher than the level L3 by a predetermined value. The timing T2 for detecting the size of the colored paper document is set to the timing when the output of the open / close detection means SB becomes a level L5 lower than the level L3 by a predetermined value. As described above, since the document size detection timings T1 and T2 are set based on the high / low level switching timing T3 of the sensor SA1, the switching timing and the document size detection timing approach each other as shown in FIG. Erroneous detection is prevented.

  Note that erroneous detection is likely to occur in the case of the original size detection timing T1, that is, in the case of detecting the size of a blank original that is detected with the original cover 1 being opened to some extent, so that the plurality of sensors SA1, SA2,. Document size detection timings T1 and T2 are set with reference to the switching timing at which switching is earliest, that is, the timing corresponding to the angle at which the opening angle of the document cover 1 is the largest. The sensors SA1, SA2,... Are arranged at different distances from the rotation axis ta of the document cover 1, but the sensor arranged at the position closest to the rotation axis 1a switches at the earliest time, so The switching point of the output of the near sensor is used to determine the document size detection timing.

  The setting is performed by opening and closing the document cover 1, monitoring the outputs of the plurality of sensors SA1, SA2,..., Reading the output T3 at the earliest timing T3 and the output L3 of the opening / closing detection means SB at the timing T3. The predetermined value is adjusted, and levels L4 and L5 are set and stored in the storage means 5.

  In the copying process and the document reading process, the document size determination unit 4 determines the document size based on the information of the levels L4 and L5 stored in the storage unit 5 and the outputs of the sensors SA1 and SA2.

  FIG. 6 shows the operation of the document size detection apparatus according to the third embodiment of the present invention.

  In the present embodiment, the probability of erroneous detection is further reduced by combining the first embodiment and the second embodiment.

  The present embodiment is the same as the second embodiment in that the document size detection timings T1 and T2 are set based on the high / low switching timing T3 of the sensors SA1 and SA2, but the timings T1 and T2 are set. By setting the output levels L4 and L5 of the open / close detection means SB for determination using the maximum level Lmax and the minimum level Lmin of the output of the open / close detection means, erroneous detection is prevented.

  That is, the level L4a higher by Δ1 than the level L3 corresponding to the earliest switching timing T3 in the output switching of the sensors SA1 and SA2 is set as the level for determining the document size detection timing T1, and the level lower by Δ2 than the level L3. The level L5a for determining the document size detection timing T2 is set. Here, Δ1 and Δ2 are the difference between the highest level and the lowest level, that is, a percentage value smaller than 100, where Lmax−Lmin is 100.

  With this setting, all parameters for determining the document size detection timings T1 and T2 are specific to the apparatus. Therefore, the document size is detected at the optimal document size detection timing for each apparatus, and the document size is detected. False detection is prevented.

  Note that the information of the levels 4a and L5a is stored in the storage means 6 as described above, and can be rewritten as necessary.

It is a figure which shows the conventional document size detection apparatus. It is a figure which shows the original document size detection apparatus which concerns on embodiment of this invention. It is a figure which shows the action | operation of the original document size detection apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the case where a misdetection occurs. It is a figure which shows the action | operation of the original document size detection apparatus which concerns on Embodiment 2 of this invention. It is a figure which shows the action | operation of the original document size detection apparatus which concerns on Embodiment 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Document cover 2 Document 3 Platen glass 4 Document size determination means 5 Storage means 6 Operation part SA1, SA2 Sensor SB Open / close detection means

Claims (9)

Platen glass on which the document is placed,
A document cover that is rotatably supported in the vicinity of one end of the platen glass and is movable to an open state that opens the platen glass and a closed state that covers the platen glass,
A document size detecting means having a light emitting element for irradiating a document and a light receiving element for receiving reflected light from the document, and disposed below the platen glass;
An open / close detecting means for detecting an open / close angle of the document cover and outputting a change in the open / close angle as a continuous value; and
A document size determination unit that reads an output of the document size detection unit and determines a document size when the document cover is closed to a predetermined angle from the output of the opening / closing detection unit;
A document size detecting device having
The document size determination means is detected based on an output level Lmax of the opening / closing detection means when the document cover is completely opened and an output level Lmin of the opening / closing detection means when the document cover is completely closed. A document size detection apparatus that determines timing and executes at least one document size detection. 2. The document size detection unit according to claim 1, wherein the document size determination unit performs the document size detection when the output of the open / close detection unit reaches a predetermined value between the output levels Lmax and Lmin. Detection device. Platen glass on which the document is placed,
A document cover that is rotatably supported in the vicinity of one end of the platen glass and is movable to an open state that opens the platen glass and a closed state that covers the platen glass,
A document size detecting means having a light emitting element for irradiating a document and a light receiving element for receiving reflected light from the document, and disposed below the platen glass;
An open / close detection means for detecting an open / close angle of the document cover and outputting a change in the open / close angle as a continuous value; and
A document size determination unit that reads an output of the document size detection unit and determines a document size when the document cover is closed to a predetermined angle from the output of the opening / closing detection unit;
A document size detecting device having
The document size detecting means has a plurality of sensors arranged at different distances from a rotation axis for opening and closing the document cover,
The document size detection device, wherein the document size determination means executes at least one document size detection at a timing set based on a high / low switching timing of one output of the plurality of sensors. 4. The timing according to claim 3, wherein the set timing is a timing at which the opening / closing detection means outputs a level higher than a level of output by the opening / closing detection means corresponding to the high / low switching timing. The document size detection device described. 5. The document size detection according to claim 3, wherein the high / low switching timing is a high / low switching timing on the most open side of the document cover among outputs of the plurality of sensors. apparatus. When the output level Lmax of the opening / closing detection means when the document cover is fully opened and the output level Lmin of the opening / closing detection means when the document cover is completely closed,
The document size detection apparatus according to claim 4, wherein the predetermined value is a value between the Lmax and the Lmin. 7. The document size detection apparatus according to claim 1, wherein the document size determination unit performs another document size detection in a state where the document cover is almost completely closed. The document size detection apparatus according to claim 2, further comprising a storage unit configured to store the predetermined value information. 9. The document size detection apparatus according to claim 8, wherein the information is rewritable.

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