JPH0514613A - Scanner - Google Patents

Abstract

PURPOSE:To provide a scanner in which the timing from the carrying start of an original till the read start of an original picture is quickly, easily and accurately adjusted. CONSTITUTION:When the tip of paper for adjusting timing reaches an exposed position, a high level output signal is inputted to the terminal G2 of a subscanning counter 76 from a digital comparator 72. Terminals G1, G2 of the subscanning counter 76 receive an output signal from a CPU 75 and the digital comparator 72 and only when an input signal to the terminal G1 is at a high level and an input signal to the terminal G2 is at a low level, a signal SH inputted to an input terminal IN from a clock generating section 70 is counted. When the carrying of paper is once stopped and restarted, the CPU 75 sends a high level signal to the input terminal G1 of the subscanning counter 76, the subscanning counter 76 starts the counting of the signal SH till the output of the digital comparator 76 reaches a high level and the CPU 75 writes the count to a memory 80.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanner for reading a document image.

[0002]

2. Description of the Related Art Generally, a scanner is used as a peripheral device of a digital computer or is incorporated in an image forming apparatus such as a digital copying machine and used as a document image reading apparatus. Also, an automatic document feeder is attached to such a scanner, and a CCD is fed by a document feeding roller.
(Photoelectric conversion element) It is also possible to automatically send a document through an image sensor. In this case, it is necessary to configure the image sensor to start reading the document image at a predetermined timing after the document transport roller starts transporting the document.

That is, for example, in a digital copying machine equipped with a scanner with an automatic document feeder, in order to match the original image with the copied image formed on the paper, it is necessary to install the copying machine or perform periodic inspection. First, it is necessary to adjust the timing between the conveyance of the document and the reading of the document image in the scanner.

For example, in the conventional timing adjusting method in a copying machine equipped with a scanner having a document circulating type automatic document feeder, a special document for timing adjustment is prepared, the document for timing adjustment is first copied, and the timing is adjusted. The adjustment original and the copied image are compared to measure the distance deviation between the images, and the distance deviation is converted into a time deviation, and this time data is stored in a battery. It is to write in a memory that is backed up such as RAM (random access memory).

That is, actual copying is performed, the amount of deviation from the position of the toner image formed on the paper is measured, the timing value at which the original image is properly placed on the paper is set, and this timing value is stored in the memory. The document feeding is controlled based on the stored timing value.

[0006]

In such a conventional scanner, the original image is copied in order to fit it properly on the sheet, and the timing adjustment original is compared with the copied image to cause a time lag. Since the amount has to be obtained, there is a problem that the operation for obtaining the displacement amount is complicated and time-consuming.

Therefore, the present invention is to provide a scanner capable of quickly, easily and accurately adjusting the timing from the start of document transportation to the start of reading of a document image.

[0008]

A scanner having a document reading unit for reading a document image at a document reading position and starting reading the document image by the document reading unit at a predetermined timing after the start of conveyance of the document, A measuring unit that measures the time interval from the start of conveyance of the adjustment paper to the detection of the leading edge of the paper by the document reading unit, a storage unit that stores data of the time interval measured by the measurement unit, and a storage unit. And a setting means for setting a predetermined timing based on the stored time interval data.

[0009]

When adjusting the timing from the start of the conveyance of the document to the start of the reading of the document image, the time interval from the start of the conveyance of the timing adjustment sheet to the detection of the leading edge of the sheet by the document reading means is Based on the output, the measuring means measures the data, and the measured time interval data is stored in the storage means. The setting means sets the above timing based on the data of the time intervals stored in the storage means. Therefore, the timing adjustment can be completed only by scanning the sheet for timing adjustment once, and the timing adjustment from the start of feeding the original to the start of reading the original image can be performed quickly, easily and accurately. ..

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, an example in which the scanner according to the present invention is applied to a digital copying machine will be described as this embodiment.

FIG. 3 is a sectional view showing the overall construction of a digital copying machine equipped with an embodiment of a scanner according to the present invention.

As shown in FIG. 1, the digital copying machine 10 of this embodiment is provided with a scanner section 11, a laser printer section 12, a multi-stage sheet feeding unit 13 and a sorter 14.

A two-sided automatic document feeder (RDF) 15 is installed above the scanner unit 11, and the scanner unit 11
Is composed of a document placing table 16 made of transparent glass, a movable scanner unit 17, and a position control device for controlling the position of the scanner unit 17.

This position control device is a scanner unit.
The position control device includes a scanner motor 18 for driving the motor 17, a pulley 19, and a wire 20 stretched between the scanner motor 18 and the pulley 19, and the position control device moves the scanner unit 17 along the longitudinal direction of the document table 16. It is configured so that it can be moved and stopped at a predetermined position.

The scanner unit 17 includes a lamp reflector assembly 21 for exposing a document, a CCD linear image sensor 22, a plurality of reflecting mirrors 23 for guiding a reflected light image from the document to the CCD linear image sensor 22, and reflected light from the document. A lens 24 for forming an image on the CCD linear image sensor 22 is included.

When scanning an original placed on the original placing table 16, the scanner section 11 reads the original image while the scanner unit 17 moves along the lower surface of the original placing table 16 and uses the RDF 15. In this case, the document image is read while the document is being conveyed while the scanner unit 17 is stopped at a predetermined position below the RDF 15.

The image data obtained by reading the original image with the scanner unit 17 is subjected to various processing by the image processing control unit included in the digital copying machine 10, and then the image processing control unit has it. Once stored in the memory, the image data in the memory is given to the laser printer unit 12 in accordance with the output instruction to form an image on a sheet.

The laser printer unit 12 is a manual document tray 2
5. A laser writing unit 26 and an electrophotographic process unit 27 for forming an image are provided.

The electrophotographic process section 27 comprises a charging device, a developing device, a transfer device, a peeling device, a cleaning device and a static eliminator around the photosensitive drum 27a according to a well-known mode. Based on the image data read from the memory of the processing controller, the laser writing unit 26 causes the laser beam to scan, thereby causing the photosensitive drum.
An electrostatic latent image is formed on the surface of 27a, the formed electrostatic latent image is visualized with toner, and the toner image is formed on the surface of the paper conveyed from the multi-stage paper feeding unit 13 or the manual feed tray 25. It is configured to electrostatically transfer, fix, and send the copied sheet to the sorter 14.

The multi-stage paper feeding unit 13 includes a first cassette 28,
Second cassette 29, third cassette 30, fourth cassette
31 and a fifth cassette 32 which can be optionally added. In the multi-stage paper feeding unit 13, the papers are sent out one by one from the papers stored in these cassettes and are conveyed toward the laser printer unit 12.

Next, the structure and operation of the RDF 15 will be described.

FIG. 4 is a sectional view of the RDF 15 attached to the scanner unit 11 of the digital copying machine 10 of FIG.

The RDF 15 sets a plurality of set originals as one.
It is configured to automatically feed the document one by one to the scanner unit 11 so that the scanner unit 17 can read one side or both sides of a document according to an operator's selection.

As shown in the figure, the RDF 15 includes a document tray 40 for setting a document 41, a document pickup roller 42 driven via an electromagnetic clutch (not shown), a pair of transport rollers 43, and a transport path of the document 41. Change lever 44 that can be switched between solenoids and a document support drum (platen roller) that can rotate in two directions (the direction of the arrow shown in the figure)
45, left and right supply rollers 46L and 46R for feeding the document 41 in cooperation with the platen roller 45, a transparent document supporting glass 47,
Left and right document guides 48L and 48R, left and right document ejection rollers
Solenoid driven left and right movable guides 50L and 50 that cooperate with 49L and 49R and document discharge rollers 49L and 49R, respectively.
R, solenoid driven movable document discharge guide 51, document discharge conveyance path 52, paper discharge roller pair 53, paper discharge tray 54, solenoid driven rotatable document reverse guide 55, document reverse guide 55
Is provided with a reversing conveyance path 56 whose one side is formed, a reversing conveyance roller pair 57 driven via an electromagnetic clutch, and a rotating shaft 58.

The distance between the platen roller 45 and the document supporting glass 47 is preferably set larger than the thickness of the document 41.

The document detecting sensor S1 ...
The signals from the document detection sensors S1 to S5, which are respectively output when the document 41 is detected, are sent to a controller (not shown).

This controller operates various electromagnetic clutches and solenoids at predetermined timings to be described later, so that a document reading position (exposure position) as described later.
The document 41 is configured to be conveyed via P.

Next, the operation of the RDF 15 will be described.

When copying only one side of the original 41, a plurality of originals 41 are set on the original tray 40 and input through an operation panel (not shown) provided in the digital copying machine 10 of FIG. Enter the copy mode (one-sided scanning of original, number of copies, copy density, etc.) with the key.

When the print switch on the operation panel of the digital copying machine is pressed, the main motor (not shown) of the RDF 15 starts rotating.

Next, the clutch of the document pickup roller 42 is turned on, and the rotating document pickup roller 42 is rotated.
Feeds only the uppermost original of the plurality of originals 41 set on the original tray 40. At this time, the conveyance roller pair
The clutch of 43 also turns on at the same time, and the pair of transport rollers 43
Is also driven to rotate.

When the leading end of the fed document 41 reaches the first document detection sensor S1, the solenoid of the change lever 44 is excited, and the change lever 44 is moved from the position shown by the alternate long and short dash line in FIG. 4 to the position shown by the solid line. Is switched to. Further manuscript 41
As the feeding is continued, the leading edge of the document 41 is guided along the side surface of the change lever 44 and guided toward the fourth document detection sensor S4.

After the leading edge of the document 41 is detected by the fourth document detection sensor S4, the conveyance of the document 41 is temporarily stopped at the timing when the document 41 is supported by the platen roller 45 and the right supply roller 46R. To do.

Next, at a predetermined timing, the clutch of the right transport roller 46R is turned on, and the document supporting glass 47R is turned on.
The feeding of the original document 41 is again started to the exposure position P.

The platen roller 45 rotates the exposure position P in the clockwise direction while the document 41 is pressed against the surface of the platen roller 45 by the document guide 48R on the right side. Pass from right to left. At the exposure position P, the image data of the document 41 is read by the scanner unit 17.

The timing from the resumption of the conveyance by the conveyance roller 46R to the start of the scanning by the scanner unit 17 is adjusted according to the present invention as described later.

The document 41 that has passed the exposure position P passes under the document guide 48L on the left side, and the document discharge roller 49L on the left side.
Will be transported to. The leading edge of the document 41 is the document discharge roller 49L
The left movable guide 50L
The solenoid is excited, and the movable guide 50L is pressed against the document discharge roller 49L with the document 41 being sandwiched.

As a result, the document discharge roller 49 is attached to the document 41.
The conveyance force is given by the frictional force of L, and the document 41 is guided along the upper surface of the document discharge movable guide 51.
After passing through 52, the paper is discharged onto the paper discharge tray 54 by the paper discharge roller pair 53.

The fifth document detection sensor S5 provided in the document discharge / transport path 52 detects the rear end of the document 41, and detects the document 41.
Is for determining that the paper has been discharged onto the paper discharge tray 54.

When a plurality of originals 41 are set on the original tray 40, the next original is fed at the timing when the trailing edge of the previous original passes the exposure position P.

The original tray 40 is provided with an original detection sensor (not shown) for detecting whether or not the original 41 is set, and the above operation is repeated until the last original 41 is exhausted.

Next, when copying both sides of the document 41,
When the print switch on the operation panel of the digital copying machine is pressed, the document pickup roller 42 feeds only the uppermost one of the plurality of documents 41 set on the document tray 40.

When the leading edge of the fed document 41 reaches the first document detection sensor S1, the clutch of the transport roller pair 43 is turned on, and the transport roller pair 43 is also driven to rotate. At this time, the solenoid of the change lever 44 is in the non-excited state, the change lever 44 is at the position shown by the alternate long and short dash line in FIG. 4, and the leading edge of the document 41 is guided toward the second document detection sensor S2. To be done.

The document 41 that has passed through the second document detection sensor S2
With the leading edge of the left side being sandwiched between the platen roller 45 and the left side supply roller 46L, the clutch of the left side conveyance roller 46L is turned off, and the conveyance of the document 41 is once stopped.

Next, at a predetermined timing, the transport roller 46L
The clutch is turned on again, and the feeding of the original 41 is started again to the exposure position P of the original supporting glass 47.

The platen roller 45 rotates the exposure position P in the counterclockwise direction while the document 41 is pressed against the surface of the platen roller 45 by the document guide 48L on the left side.
The document 41 passes through the exposure position P from left to right in FIG.
In this way, the exposure scanning of one side of the document 41 is started. The scanner unit 17 waits for the transport roller 46L to resume transport.
Similarly, the timing until the scanning by is started is adjusted according to the present invention.

The document 41 that has passed the exposure position P passes under the document guide 48R on the right side, and the document discharge roller 49R on the right side.
Sent to. The solenoid of the movable guide 50R on the right side is excited at the timing when the leading edge of the document 41 reaches the document discharge roller 49R, and the movable guide 50R is pressed against the document discharge roller 49R with the document 41 being sandwiched.

The document 41 conveyed by being sandwiched by the movable guide 50R and the document discharge roller 49R is guided to the reversing conveyance path 56, and is conveyed by the reversing conveyance roller pair 57 toward the third document detection sensor S3. It

When the leading edge of the document 41 reaches the third document detecting sensor S3, the solenoid of the document reversing guide 55 is excited to cause the document reversing guide 55 to move from the position indicated by the solid line about the pivot shaft 58 thereof to the alternate long and short dash line. The reversal conveyance path 56 is opened by rotating along the arrow shown in the figure to the position indicated by. At the same time, the solenoid of the change lever 44 is excited and the change lever 44
Is switched from the position indicated by the alternate long and short dash line to the position indicated by the solid line.

The leading edge of the original 41 is further provided with a pair of reverse conveying rollers 57.
It is guided by the conveyance roller pair 43 by the side of the change lever 44, which is switched to the position shown by the solid line, and is guided toward the fourth document detection sensor S4. Then, when the leading edge of the document 41 is sandwiched between the platen roller 45 and the right supply roller 46R, the conveyance of the document 41 is temporarily stopped.

In this state, the reverse conveyance path length (from the contact point of the platen roller 45 and the supply roller 46R to the fourth document detection sensor S4, the change lever 44, the conveyance roller pair 43, the third document detection sensor S3, If the length of the document is longer than the length between the movable roller pair 57 and the reversing conveyance path 56 and the contact point between the movable guide 50R and the document discharge roller 49R), rotation of the document reversing guide 55 causes Since the reverse conveyance path 56 is open, even if the leading edge of the document is stopped, the portion of the document after the reverse conveyance roller pair 57 is moved from the position sandwiched by the reverse conveyance roller pair 57 to the movable guide 50R. A natural flexure is formed between the position sandwiched between the sheet and the document discharge roller 49R.

Reversing conveyance path by rotation of the document reversing guide 55
The open degree of 56 depends on, for example, the size of the document detected by a document size detection device (not shown) capable of detecting the document size, or the size of the document input by the operator through the input keys on the operation panel. The opening degree may be set in advance so that the reversal conveyance path 56 is opened.

Next, after the trailing edge of the document 41 has passed the exposure position P, the document is fed again to the exposure position P of the document supporting glass 47 at the timing with the scanner unit 17.

On the platen roller 45, the document 41 is guided by the document guide 48.
While being pressed against the surface of the platen roller 45 by R, the exposure position P is rotated in the clockwise direction, and the document 41 passes through the exposure position P from right to left in FIG. At the exposure position P, the image data of the document 41 is changed to the scanner unit 17
Read by

The original 41 that has passed the exposure position P passes below the original guide 48L on the left side and the original discharge roller 49L on the left side.
Will be transported to. The leading edge of the document 41 is the document discharge roller 49L
The left movable guide 50L
The solenoid of is excited and the movable guide 50L is pressed against the document discharge roller 49L while the document 41 is sandwiched, and the document 41
To transport.

When the reading of the image on the second side of the document 41 is completed, the solenoid of the document reversing guide 55 is de-energized, the document reversing guide 55 returns to the position shown by the solid line, and the leading edge of the next document 41 is reached. It waits to guide the sheet to the reverse conveyance roller pair 57.

The document 41 conveyed by being sandwiched between the movable guide 50L and the document discharge roller 49L is guided along the upper surface of the document discharge movable guide 51, passes through the document discharge / conveyance path 52, and a pair of discharge rollers. The sheet is discharged onto the sheet discharge tray 54 by 53.

When a plurality of originals 41 are set on the original tray 40, when the rear end of the original passes the exposure position P at the time of scanning exposure of the second surface of the previous original, the next Will be sent.

The above-mentioned operation is repeated until the last document 41 is left on the document tray 40. FIG. 5 is a plan view showing an example of a marker on a sheet for timing adjustment.

After the conveyance of the document 41 by the right supply roller 46R or the left supply roller 46L is restarted, the timing until the leading edge of the document 41 reaches the exposure position P and the scanning by the scanner unit 17 starts is as follows. For example, by using the sheet 60 for timing adjustment shown in FIG. 5, adjustment can be performed as described later.

That is, as shown in the figure, black markers 61 are provided on both sides at one end of the timing adjusting paper 60. Alternatively, a black solid paper for adjusting the timing, which is painted black on both sides, may be used.

Next, the timing adjustment using the timing adjustment sheet 60 will be described.

When the timing adjustment is performed, first, referring to FIG.
The document leading edge adjustment mode is selected by the input key of the operation panel (not shown) provided in the digital copying machine 10 of FIG. 5, and then the timing adjustment paper 60 shown in FIG. Set it on the document tray 40 of the RDF 15 so that it is on the advancing side.

FIG. 1 is a block configuration diagram of an embodiment of a timing adjusting circuit of a CCD sensor included in a scanner according to the present invention, and FIG. 2 is a time chart showing a sequence of operations of main elements of the circuit of FIG. It is a chart.

As shown in these figures, the clock generator
Reference numeral 70 is configured to generate a clock signal CK for controlling the main scanning of the CCD sensor 90 for each pixel and a signal SH for controlling the timing of the main scanning of the CCD sensor 90.

The CCD sensor 90 corresponds to the CCD linear image sensor 22 shown in FIG. 3, and is driven by the clock signal CK and the signal SH. The signal SH is obtained by dividing the frequency of the clock signal CK.

The analog data output from the CCD sensor 90 is output by the A / D (analog / digital) converter 71.
For example, it is digitally converted into 8-bit binary data and input to the digital comparator 72 and the sub-scanning cutout unit 73.

On the other hand, the clock signal CK is the main scanning counter.
Input to 74 input terminal IN. The main scanning counter 74 is configured to activate the digital comparator 72 when the main scanning reaches the middle of the width of the timing adjusting sheet. That is, the main-scanning counter 74 counts the number of pixels in the main-scanning with the signal SH as a reference, and when it counts up to a value preset by the central processing unit (CPU) 75, the output terminal OUT of the main-scanning counter 74 goes high. The level is set and the digital comparator 72 is activated.

In the embodiment shown in FIG. 5, since the black marker 61 of the timing adjusting paper 60 is located at the center in the width direction of the paper, the count value of the main scanning counter 74 is set to the total number of pixels in the main scanning. 1/2 value (eg 400 DPI, main scan width 300 m
m, and the total number of pixels is 5000, the count value can be preset to 2500).

The digital comparator 72 has a leading edge of the paper 60 for timing adjustment, more specifically, the marker 61 has an exposure position P.
It is configured to be able to detect the timing to reach the. When the data input from the A / D converter 71 is 8-bit data, and the white level is 0 gradation and the black level is 256 gradations, for example, the threshold value of the digital comparator 72 is set in advance to an intermediate value 128 thereof. If set, the output terminal OUT of the main scanning counter 74 becomes a high level when the main scanning proceeds to the central area of the timing adjusting paper 60, that is, when the marker 61 reaches the exposure position P, the digital comparator 72 outputs. The output terminal OUT goes high. This high-level output signal is input to the input terminal G2 of the sub-scanning counter 76.

The sub-scanning counter 76 receives the signal SH from the clock generator 70 at the input terminal IN, the output signal from the CPU 75 at the input terminal G1, and the output signal from the digital comparator 72 at the input terminal G2. Sub-scanning counter
The 76 is configured to count the signal SH input to the input terminal IN only when the output signal from the CPU 75 is high level and the output signal from the digital comparator 72 is low level.

The CPU 75 is configured to control the clutch of the right supply roller 46R and the clutch of the left supply roller 46L included in the RDF 15 of FIG. 4 via the inverter 77. As described above, the CPU 75 turns on the clutch 78 of the supply roller 46R or the clutch 79 of the supply roller 46L when temporarily stopping the conveyance of the document and restarting the conveyance when reading the image on the back surface or the front surface of the document ( At the same time as point (a) in FIG. 2, a high level signal is sent to the input terminal G1 of the sub-scanning counter 76.

Therefore, the sub-scanning counter 76 starts counting the signal SH when the clutch 78 or 79 is turned on (time (a) in FIG. 2) in order to restart the conveyance of the original,
The signal SH is output until the output terminal OUT of the digital comparator 72 becomes high level, that is, until the point (b) in FIG. 2 at which the leading edge of the paper 60 for timing adjustment reaches the exposure position P.
Count the number of times. The CPU 75 reads this count value via the DATA OUT signal line, and has a built-in memory (for example, RAM) in the CPU 75 backed up by a battery.
Write to 80.

In this way, the paper for timing adjustment
As shown in FIG. 2, the time interval T1 or T2 from when the conveyance of 60 is once stopped and the supply roller 46R or 46L resumes the conveyance of the sheet 60 until the CCD sensor 90 detects the leading edge of the sheet 60 is as shown in FIG. Based on the output signal from the CCD sensor 90, it is measured according to the resolution of the signal SH and stored in the memory 80. The time intervals T1 and T2 are time intervals obtained as a result of the adjustment by the back surface and the front surface of the paper 60 for timing adjustment.

Therefore, in order to measure the time interval T1 or T2 and store it in the memory 80, it is sufficient to scan the timing adjusting paper 60 only once. The signal SH
Is the clock of the crystal oscillator of the clock generator 70, but the data from the CCD sensor 90 is the signal SH.
Is output in units (that is, in line units), the resolution of the signal SH is practically sufficient.

In normal reading of an original, depending on whether the image on the back or front of the original is read, the CP
U75 is the above-mentioned time interval T1 or T stored in the memory 80.
By writing the value of 2 into the sub-scanning counter inside the sub-scanning cutout unit 73, the timing of reading the original image by the CCD sensor 90 is set. Therefore, after the supply roller 46R or 46L starts conveying the original to be copied, the reading of the original image is started at the timing of the above-mentioned time interval T1 or T2.

Since the CPU 75 presets the number of effective pixels in the main-scan cut-out section 81 according to the size of the original to be copied, the output of the main-scan cut-out section 81 is sent to the image processing section 82 as effective image data, and the image is processed. Image processing (MTF correction, shading, density conversion, scaling processing, etc.) is performed in the processing unit, and the image data is output to the laser writing unit 26 in FIG.

The CCD sensor 90 is an embodiment of the document reading means of the present invention. The digital comparator 72, the main scanning counter 74, the CPU 75 and the sub scanning counter 76 are an embodiment of the measuring means of the present invention. The memory 80 is an embodiment of the storage means of the present invention. Sub-scanning cutout unit 73 and CPU 75
Is an embodiment of the setting means of the present invention.

According to the above-described embodiment, the timing from the start of feeding the original to the start of reading the original image is automatically stored in the memory by scanning the timing adjusting sheet once, so that the timing The adjustment can be automated. Therefore, the timing adjustment can be processed quickly, easily and accurately, which contributes to the improvement of the serviceability, productivity and reliability of the scanner. In addition, timing adjustment can be easily performed without specialized knowledge.

[0080]

As described above, according to the present invention, the document reading unit for reading the document image at the document reading position is provided, and the document reading unit starts reading the document image at a predetermined timing after the conveyance of the document starts. A scanner, measuring means for measuring a time interval from the start of conveyance of the timing adjusting paper to the detection of the leading edge of the paper by the document reading means, and a memory for storing data of the time interval measured by the measuring means. Means and setting means for setting a predetermined timing based on the data of the time interval stored in the storage means. Therefore, from the start of feeding the original to the start of reading the original image quickly, easily and accurately. The timing can be adjusted.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a timing adjustment circuit of a CCD sensor included in a scanner according to the present invention.

FIG. 2 is a time chart showing a sequence of operations of main elements of the circuit of FIG.

FIG. 3 is a cross-sectional view showing the overall configuration of a digital copying machine including an embodiment of a scanner according to the present invention.

4 is a cross-sectional view of the RDF attached to the scanner unit of the digital copying machine of FIG.

FIG. 5 is a plan view showing an example of a marker on a sheet for timing adjustment.

[Explanation of symbols]

 10 Digital copying machine 11 Scanner section 15 RDF 22 CCD linear image sensor 46R, 46L Conveying roller 71 A / D converter 72 Digital comparator 73 Sub scanning cutout section 74 Main scanning counter 75 CPU 76 Sub scanning counter 77 Inverter 80 Memory 90 CCD sensor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H04N 1/12 Z 7037-5C

Claims (1)

Claims: What is claimed is: 1. A scanner which comprises an original reading unit for reading an original image at an original reading position, and which starts reading the original image by the original reading unit at a predetermined timing after the start of conveyance of the original. Measuring means for measuring the time interval from the start of the conveyance of the timing adjusting paper to the detection of the leading edge of the paper by the document reading means, and a memory for storing the data of the time interval measured by the measuring means. A scanner comprising: a means and a setting means for setting the predetermined timing based on the time interval data stored in the storage means.