JP7147438B2 - Image reading device, image forming device and image reading method - Google Patents

Description

The present invention relates to an image reading device, an image forming device, and an image reading method.

Conventionally, misalignment of the photoelectric conversion element occurs due to twisting or distortion of the reading device during attachment, or due to variation in the arrangement position of each element when forming the reading device by arranging a plurality of photoelectric conversion elements. It is known.

Japanese Patent Application Laid-Open No. 2002-200000 discloses a technique for reading an image of a reference line, detecting a positional deviation of a reading device, and correcting the image position.

By the way, in recent years, when the reading range cannot be covered by one reading device, a plurality of reading devices are used.

However, according to the conventional image position correction technology, the size of the member holding the reference line must be increased as the reading range is expanded, and the cost is high in order to achieve the same degree of scale accuracy as with a small size. There was a problem of becoming

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and an object of the present invention is to achieve the same degree of accuracy as a small-sized position reference member at low cost even if the reading range is expanded.

In order to solve the above-described problems and achieve the object, the present invention provides at least two reading devices arranged in a predetermined direction perpendicular to the direction in which an object to be read is conveyed; a position reference member having a reference pattern serving as a reference for correcting relative positions between devices and moving relative to the reading device in a direction orthogonal to the predetermined direction; and at least two reading devices. correction value calculation means for calculating a correction value, which is a deviation of the relative position of each of the reading devices and between the reading devices, based on the reading result of the position reference member by the reading device, wherein the position reference member A first position reference member for correcting a relative position between devices and a second position reference member for correcting a relative position within the reading device, wherein adjacent ends of the first position reference member and the end of the second position reference member are positioned in the same reading area in the same reading device.

According to the present invention, even if the reading range is expanded, it is possible to achieve the same level of accuracy as a small-sized position reference member at low cost.

FIG. 1 is a schematic diagram showing an example of the configuration of a printing system according to the first embodiment. FIG. 2 is a block diagram showing an example of electrical connections of hardware in the printing system. FIG. 3 is a schematic diagram showing how the reading device and the position reference member are installed. FIG. 4 is a diagram exemplifying the arrangement relationship between the reading device and the position reference member. FIG. 5 is a diagram exemplifying the positional relationship between the reading device and the recording paper. FIG. 6 is a diagram exemplifying the relative positional deviation of the arrangement of the position reference members. FIG. 7 is a functional block diagram showing the functional configuration of the printing system. FIG. 8 is a diagram showing a method of calculating correction values for misalignment in the main scanning direction between reading devices. FIG. 9 is a diagram showing a method of calculating correction values for positional deviation in the sub-scanning direction between reading devices. FIG. 10 is a diagram showing a method of calculating a correction value for misregistration in the main scanning direction within the reading device. FIG. 11 is a diagram showing a method of calculating a positional deviation correction value in the sub-scanning direction within the reading device. FIG. 12 is a diagram for explaining correction of the reading device in the main scanning direction. 13A and 13B are diagrams for explaining correction in the sub-scanning direction of the reading device. FIG. 14 is a flowchart schematically showing the flow of processing executed by the printing system. FIG. 15 is a flowchart schematically showing the flow of processing in the correction value calculation mode. FIG. 16 is a flowchart schematically showing the flow of processing in read mode. FIG. 17 is a perspective view of the appearance of the image reading apparatus according to the second embodiment. FIG. 18 is a side view partially showing the internal structure of the image reading device.

Exemplary embodiments of an image reading apparatus, an image forming apparatus, and an image reading method will be described in detail below with reference to the accompanying drawings. In the following, the case where the image reading device and the image forming device are applied to a printing system including a printing device such as a commercial printing machine (production printing machine) that continuously prints a large number of sheets in a short time is taken as an example. It is described, but not limited to.

(First embodiment)
[Description of the hardware configuration of the printing system]
FIG. 1 is a schematic diagram showing an example of the configuration of a printing system 1 according to the first embodiment. As shown in FIG. 1, a printing system 1 as an image forming apparatus includes a paper discharge unit 102, a cooling unit 103, a drying unit 104, an image forming unit 105, a registration unit 106, a pre-coating unit 107, and a paper feed unit 108 .

The paper feed unit 108 accommodates a recording medium to be processed (an object to be transported), and supplies the recording medium to the imaging unit 105 or the like in the subsequent stage. Examples of the recording medium include, but are not limited to, recording paper (transfer paper), and examples include coated paper, thick paper, OHP (Overhead Projector) sheets, plastic films, copper foils, and the like, on which images can be recorded. Any medium may be used. In the present embodiment, the processing target (conveyed object) is a recording medium on which an image is formed. transported object).

The pre-coating unit 107 coats the recording paper (transfer paper), which is the processing target (transported object) supplied from the paper feeding unit 108, with the pre-coating liquid. As a result, the ink ejected by the image forming unit 105 can be applied even to different recording papers.

A registration unit 106 is a unit that adjusts the transport timing and position of the recording paper with respect to the image forming unit 105 .

The image forming unit 105 is an inkjet printing apparatus, and forms an image by ejecting ink onto recording paper. In the present embodiment, an inkjet printing apparatus is used as the image forming unit 105, but the present invention is not limited to this, and an electrophotographic printing apparatus may be used.

The drying unit 104 has a role of drying the ink adhered to the recording paper by the image forming unit 105 and making it familiar.

A cooling unit 103 cools the recording paper heated by the drying unit 104 .

In the case of single-sided printing, the cooling unit 103 sends the printed matter, which is the recording paper on which the image is formed, to the subsequent paper discharge unit 102 . On the other hand, the cooling unit 103 sends the recording paper on which the image is formed to the reversing path 109 in the case of double-sided printing.

The reversing path 109 reverses the front side and the back side of the recording paper and conveys it by switching back the recording paper. The recording paper transported by the reversing path 109 is transported again to the image forming unit 105, the image forming unit 105 forms an image on the surface opposite to the previous one, and the drying unit 104 and the cooling unit 103 dry and cool the paper. It is sent to the subsequent discharge unit 102 as a printed matter.

The paper discharge unit 102 receives the paper output of the printed material generated through the image forming unit 105 , the drying unit 104 and the cooling unit 103 .

In addition, the image forming unit 105 detects the edge of the conveyed recording paper and the position of the image recorded on the recording paper in order to correct the relative position between the plurality of reading devices and for each pixel of one reading device. A detection device 200 is provided.

The detection device 200 includes a reading device 201 and a position reference member 202. As shown in FIG.

The reading device 201 can be realized by, for example, a CIS (Contact Image Sensor) in which a plurality of imaging elements (CMOS image sensors) are arranged in a line. The reading device 201 receives reflected light from an object to be read and outputs an image signal. Specifically, the reading device 201 scans the transport position of the recording paper on which the image is formed by the image forming unit 105 and the image forming position on the recording paper. Further, the reading device 201 uses the position reference member 202 as a reading target.

The CIS applied to the reading device 201 generally has a configuration in which a plurality of sensor chips 210 (see FIG. 4) having a plurality of pixels are arranged in the main scanning direction to ensure the required effective reading length in the main scanning direction. Known for

The position reference member 202 is a reference plate for correcting the mounting position of each sensor chip 210 of the reading device 201 configured by a plurality of sensor chips 210 . By correcting the attachment position of each sensor chip 210 of the reading device 201 using the position reference member 202 in this manner, highly accurate image position detection is performed.

If the reading device 201 expands or contracts due to the influence of heat generated by the surrounding members, it does not function as an absolute position reference, resulting in deterioration of the position detection accuracy. Therefore, the position reference member 202 is made of a material that has a linear expansion coefficient lower than that of the substrate of the reading device 201 and that expands and contracts due to the influence of the ambient temperature in position detection so small that it can be ignored. In this embodiment, the position reference member 202 is made of glass in consideration of the assumed temperature change range and linear expansion coefficient. Note that the material of the position reference member 202 is not limited to this, and quartz glass or the like is preferably used in order to achieve highly accurate medium position detection when the temperature change range of the reading device 201 is wide. be.

FIG. 2 is a block diagram showing an example of electrical connections of hardware in the printing system 1. As shown in FIG.

As shown in FIG. 2, the printing system 1 has a configuration in which a controller 10, an engine section (Engine) 60, and an engine section (Engine) 70 are connected by a PCI bus. The controller 10 is a controller that controls the overall control of the printing system 1, drawing, communication, and input from an operation panel 100 that is an operation display unit. The engine unit 60 is an engine that can be connected to the PCI bus, and is, for example, a scanner engine such as the detection device 200 or the like. The engine section 60 includes an image processing section such as error diffusion and gamma conversion in addition to the engine section. The engine section 70 is an engine that can be connected to the PCI bus, and is, for example, a print engine section such as the image forming unit 105 or the like.

The controller 10 includes a CPU (Central Processing Unit) 11, a north bridge (NB) 13, a system memory (MEM-P) 12, a south bridge (SB) 14, a local memory (MEM-C) 17, an ASIC (Application Specific Integrated Circuit) 16 and a hard disk drive (HDD) 18 , and a north bridge (NB) 13 and ASIC 16 are connected by an AGP (Accelerated Graphics Port) bus 15 . The MEM-P 12 further has a ROM 12a and a RAM 12b.

The CPU 11 performs overall control of the printing system 1, has a chipset consisting of NB13, MEM-P12 and SB14, and is connected to other devices via this chipset.

The NB 13 is a bridge for connecting the CPU 11 with the MEM-P 12, SB 14 and AGP bus 15, and has a memory controller for controlling reading and writing with respect to the MEM-P 12, a PCI master and an AGP target.

The MEM-P 12 is a system memory used as a memory for storing programs and data, a memory for developing programs and data, a drawing memory for a printer, etc., and consists of a ROM 12a and a RAM 12b. The ROM 12a is a read-only memory used as a memory for storing programs and data, and the RAM 12b is a writable and readable memory used as a memory for developing programs and data, a drawing memory for a printer, and the like.

SB 14 is a bridge for connecting NB 13 with PCI devices and peripheral devices. The SB 14 is connected to the NB 13 via a PCI bus, to which a network interface (I/F) unit and the like are also connected.

The ASIC 16 is an image processing IC (Integrated Circuit) having hardware elements for image processing, and serves as a bridge connecting the AGP bus 15, PCI bus, HDD 18 and MEM-C 17, respectively. This ASIC 16 includes a PCI target and AGP master, an arbiter (ARB) that forms the core of the ASIC 16, a memory controller that controls the MEM-C 17, and multiple DMACs (Direct Memory) that rotate image data by hardware logic. Access Controller) and a PCI unit that transfers data between the engine section 60 and the engine section 70 via the PCI bus. A USB 40 and an IEEE 1394 (the Institute of Electrical and Electronics Engineers 1394) interface (I/F) 50 are connected to the ASIC 16 via a PCI bus. Operation panel 100 is directly connected to ASIC 16 .

The MEM-C 17 is a local memory used as an image buffer and code buffer, and the HDD 18 is a storage for storing image data, programs, font data, and forms.

The AGP bus 15 is a bus interface for graphics accelerator cards proposed for speeding up graphics processing, and speeds up the graphics accelerator card by directly accessing MEM-P12 with high throughput. is.

The program executed by the printing system 1 of the present embodiment is a file in an installable format or an executable format, and can be stored on a computer such as a CD-ROM, a flexible disk (FD), a CD-R, a DVD (Digital Versatile Disk), or the like. may be recorded on a recording medium readable by .

Furthermore, the program executed by the printing system 1 of this embodiment may be stored on a computer connected to a network such as the Internet, and provided by being downloaded via the network. Also, the program executed by the printing system 1 of this embodiment may be provided or distributed via a network such as the Internet.

[Description of detection device 200]
Next, the detection device 200 will be described.

FIG. 3 is a schematic diagram showing how the reading device 201 and the position reference member 202 are arranged. As shown in FIG. 3, the position reference member 202 is provided on a rotating member (revolver) 203 that is rotationally driven by a motor 204 . The position reference member 202 is moved by a rotating member 203 that is rotated at a constant speed by a motor 204 . The position reference member 202 is arranged on the opposite surface of the reading device 201 at a predetermined timing as the rotating member 203 rotates.

The rotating member 203 is also provided with a reading background 205 used for detecting the edge of the conveyed recording paper and the position of the image recorded on the recording paper. The position reference member 202 and the reading background 205 are selectively switched to a position facing the reading device 201 by rotating the rotating member 203 driven by the motor 204 .

Further, the reason why the position reference member 202 is rotated is to move the position reference member 202 at a constant speed in the sub-scanning direction so that the position reference member 202 can detect the mounting inclination of the reading device 201 in the sub-scanning direction. This is for reading the primary and secondary scales (see FIG. 4), which are reference patterns that include lines that are arranged and extend in a predetermined direction.

In FIG. 3, the position reference member 202 is attached to the rotating member 203 so as to move the position reference member 202 at a constant speed in the sub-scanning direction, but the present invention is not limited to this. For example, the position reference member 202 may be provided so as to be linearly movable.

Next, the positional relationship between the reading device 201 and the position reference member 202 will be described.

Here, FIG. 4 is a diagram exemplifying the positional relationship between the reading device 201 and the position reference member 202, and FIG. As shown in FIG. 4, in the present embodiment, a plurality of reading devices 201 (201a, 201b) are arranged in a direction (main scanning direction) a perpendicular to the conveying direction (sub-scanning direction) b of the recording paper. It is As shown in FIG. 5, the plurality of reading devices 201 (201a, 201b) are not arranged over the entire width of the recording paper P because the width of the recording paper P, which is the reading range, is large. are arranged at both ends of the recording paper P, respectively.

Two types of position reference members 202 (202a, 202b) are arranged for these reading devices 201 (201a, 201b). The position reference member 202a, which is the first position reference member, and the position reference member 202b, which is the second position reference member, are arranged on a straight line with respect to the main scanning direction a. If the position reference members 202a and 202b are arranged on a straight line with respect to the main scanning direction a, the plurality of position reference members 202 (202a and 202b) can be simultaneously scanned by the reading device 201 (201a and 201b). Since it can be read, it is advantageous in that it takes a short time to read the position reference member 202 (202a, 202b) between sheets. Also, the paper interval can be shortened to improve productivity.

As shown in FIG. 4, a predetermined primary and secondary scale X is arranged on the position reference member 202 (202a, 202b). As shown in FIG. 4, the main and sub-scales X arranged on the position reference members 202 (202a, 202b) are formed by lines parallel to the main scanning direction (predetermined direction) of the reading device 201 (hereinafter "horizontal lines"). ) and perpendicular lines extending in a direction perpendicular to the main scanning direction of the reading device 201 (hereinafter referred to as “vertical lines”).

As shown in FIG. 4, vertical lines are drawn corresponding to each sensor chip 210 on the position reference member 202 (202a, 202b) so that each sensor chip 210 on the substrate of the reading device 201 can be read. arranged at intervals. Also, the horizontal lines are arranged between the vertical lines.

Incidentally, as shown in FIG. 4, by creating a gap between the vertical line and the horizontal line on the position reference member 202 (202a, 202b), if the vertical line is read, the horizontal line is within the reading range of the reading device 201. The coordinates of the vertical line can be calculated even if the

The position reference member 202 a functions as a reference for correction between the reading devices 201 . The position reference members 202a are arranged so that the main and subscales X are positioned corresponding to the sensor chips 210 of the adjacent reading devices 201, respectively.

The position reference member 202b functions as a reference for correction within the reading device 201. FIG. The position reference member 202b is arranged so that the main and subscales X are positioned corresponding to all the sensor chips 210 of each reading device 201. FIG.

The main and subscales X at the ends of the adjacent position reference members 202 (202a, 202b) are located in the reading area of the same sensor chip 210. FIG.

Next, the positional relationship between the reading device 201 and the recording paper P will be described.

Interval A shown in FIG. 5 represents the relative position between sensor chips 210 (pixels) within one reading device 201 . Interval B in FIG. 5 represents the relative position between the plurality of reading devices 201 (201a, 201b). If the distance A and the distance B are known values, the reading device 201 (201a, 201b) is positioned at both ends of the recording paper P as shown in FIG. The edge of P and the position of the image recorded on the recording paper P can be accurately detected.

By the way, the arrangement of the position reference members 202 (202a, 202b) as shown in FIG. 5 is strictly an ideal arrangement. In practice, the reading device 201 (201a, 201b) includes various manufacturing variations and mounting variations. Here, FIG. 6 is a diagram exemplifying the relative positional deviation of the arrangement of the position reference members 202 (202a, 202b).

FIG. 6A shows the deviation (main scanning direction) between the reading devices 201 (201a, 201b). Such a deviation occurs due to variations in assembly of the reading device 201 (201a, 201b).

FIG. 6B shows the deviation (sub-scanning direction) between the reading devices 201 (201a, 201b). Such a deviation occurs due to variations in assembly of the reading device 201 (201a, 201b).

FIG. 6C shows the deviation (main scanning direction) within the reading device 201 (201a, 201b). Such a deviation occurs due to variations in manufacturing of the reading devices 201 (201a, 201b) and temperature fluctuations over time.

FIG. 6D shows the deviation (sub-scanning direction) within the reading device 201 (201a, 201b). Such a deviation occurs due to variations in assembly of the reading device 201 (201a, 201b).

FIG. 6(e) shows the deviation (sub-scanning direction) within the reading device 201 (201a, 201b). Such a deviation occurs due to manufacturing variations of the reading device 201 (201a, 201b).

The reading device 201 (201a, 201b) cannot accurately detect the edge of the recording paper P and the position of the image recorded on the recording paper P unless the misalignment shown in FIG. 6 is corrected.

Therefore, in the present embodiment, the misalignment shown in FIG.

[Description of Functional Configuration of Printing System 1]
Next, the functions exhibited by the CPU 11 of the printing system 1 executing the programs stored in the HDD 18 and ROM 12a will be described. Here, description of conventionally known functions will be omitted, and the positional deviation correction function of the reading device 201 (201a, 201b), which is a characteristic function of the printing system 1 of the present embodiment, will be described in detail. describe.

FIG. 7 is a functional block diagram showing the functional configuration of the printing system 1. As shown in FIG.

As shown in FIG. 7, the CPU 11 of the printing system 1 functions as a reading control section 110, a motor control section 111, and a correction value calculation section 112. FIG.

In this embodiment, the characteristic functions of the printing system 1 are realized by the CPU 11 executing a program. Some or all of them may be realized by dedicated hardware circuits.

The motor control unit 111 outputs a drive signal to the motor 204 to rotationally drive the rotating member 203 . The motor control unit 111 also outputs a drive stop signal to the motor 204 to stop the rotation of the rotating member 203 .

The reading control unit 110 outputs a reading start signal to the reading device 201 (201a, 201b) to start reading by the reading device 201 (201a, 201b). Further, upon receiving a read signal from the reading device 201 (201a, 201b), the reading control unit 110 outputs a reading end signal to the reading device 201 (201a, 201b), and the reading device 201 (201a, 201b) finish reading.

The correction value calculator 112 functions as a correction value calculator. The correction value calculation unit 112 controls the motor control unit 111 and the reading control unit 110, and calculates correction values between the reading devices 201 (201a, 201b) and within the reading devices 201 (201a, 201b). More specifically, the correction value calculation unit 112 controls the motor control unit 111 to position the position reference member 202 (202a, 202b) facing the reading device 201 (201a, 201b), and controls the reading control unit 110. and read by the reading device 201 (201a, 201b). Further, the correction value calculator 112 calculates a correction value and stores the calculated correction value in the HDD 18, RAM 12b, or the like, which is a storage unit.

The reading background 205 is positioned opposite the reading device 201 (201a, 201b) under the control of the motor control unit 111 when detecting the edge of the conveyed recording paper or the position of the image recorded on the recording paper. Let me. In this state, the CPU 11 of the printing system 1 reads the edge of the conveyed recording paper and the position of the image recorded on the recording paper with the reading device 201 (201a, 201b), and reads data stored in the HDD 18, RAM 12b, etc. The reading result is corrected based on the correction values between the devices 201 (201a, 201b) and the correction values within the reading devices 201 (201a, 201b).

Next, calculation of the correction value in the correction value calculator 112 will be described.

First, correction of misalignment in the main scanning direction between the reading devices 201 (201a and 201b) will be described.

FIG. 8 is a diagram showing a method of calculating correction values for misalignment in the main scanning direction between reading devices. As shown in FIG. 8A, first, the correction value calculator 112 reads vertical lines of the position reference member 202a with the sensor chips 210 predetermined for each of the adjacent reading devices 201 (201a, 201b). In addition, in FIG. 8A, the area indicated by the frame A1 on the position reference member 202a is the reading area of the sensor chip 210. As shown in FIG.

The correction value calculation unit 112 can specify the pixel position of the vertical line of the position reference member 202a on the sensor chip 210 from the reading result, as shown in FIG. 8B.

The correction value calculation unit 112 can accurately calculate the main scanning distance between the reading devices 201 (201a and 201b) from the above results, and can calculate the deviation from the ideal position as a correction value.

Next, correction of positional deviation in the sub-scanning direction between the reading devices 201 (201a and 201b) will be described.

FIG. 9 is a diagram showing a method of calculating correction values for positional deviation in the sub-scanning direction between reading devices. As shown in FIG. 9A, first, the correction value calculation unit 112 rotates the rotating member 203 to move the position reference member 202a in the sub-scanning direction at a constant speed, while moving the horizontal line of the position reference member 202a to A predetermined sensor chip 210 is used to read each adjacent reading device 201 (201a, 201b). In addition, in FIG. 9A, the area indicated by the frame A2 on the position reference member 202a is the reading area of the sensor chip 210. As shown in FIG.

The correction value calculation unit 112 can specify, from the result of reading, in which line of the number of reading lines the horizontal line of the position reference member 202a is located (sub-scanning position), as shown in FIG. 9B.

The correction value calculation unit 112 can accurately calculate the sub-scanning distance between the reading devices 201 (201a and 201b) from the above results, and can calculate the deviation from the ideal position as a correction value. In addition, when taking into account variations in pixel positions within the sensor chip 210, calculation may be performed by averaging in the sub-scanning direction.

As described above, according to the method shown in FIGS. 8 and 9, it is possible to calculate correction values for deviations in the main scanning direction and sub-scanning direction between adjacent reading devices 201 (201a and 201b).

It should be noted that when calculating correction values for deviations in the main scanning direction and sub-scanning direction between adjacent reading devices 201 (201a and 201b), horizontal lines of the position reference member 202 and vertical lines of the position reference member 202 are read. It doesn't matter which one comes first.

Next, correction of misalignment in the main scanning direction within the reading device 201 (201a, 201b) will be described.

FIG. 10 is a diagram showing a method of calculating a correction value for misregistration in the main scanning direction within the reading device. As shown in FIG. 10A, first, the correction value calculator 112 reads vertical lines of the position reference member 202b corresponding to all sensor chips 210 of the reading device 201 (201a, 201b). In addition, in FIG. 10A, the area indicated by the frame A3 in the position reference member 202b is the reading area of all the sensor chips 210. As shown in FIG.

As shown in FIG. 10B, the correction value calculation unit 112 determines, based on the result of the reading, that the vertical line of the position reference member 202b corresponds to the pixel position of each sensor chip 210 of the reading device 201 (201a, 201b). It is possible to identify whether

The correction value calculator 112 can calculate the position of the sensor chip 210 in the reading device 201 (201a, 201b) from the above results, and can calculate the deviation from the ideal position as a correction value.

Next, correction of positional deviation in the sub-scanning direction within the reading device 201 (201a, 201b) will be described.

FIG. 11 is a diagram showing a method of calculating a positional deviation correction value in the sub-scanning direction within the reading device. As shown in FIG. 11A, first, the correction value calculation unit 112 rotates the rotating member 203 to move the position reference member 202a in the sub-scanning direction, while all the sensors of the reading device 201 (201a, 201b) are A horizontal line on the position reference member 202b corresponding to the chip 210 is read. In addition, in FIG. 11A, the area indicated by the frame A4 on the position reference member 202b is the reading area of each sensor chip 210. As shown in FIG.

Based on the reading result, the correction value calculation unit 112 determines, as shown in FIG. position) can be specified.

The correction value calculation unit 112 can calculate the sub-scanning distance within the reading device 201 (201a, 201b) from the above results, and can calculate the deviation from the reference position as a correction value if an arbitrary sensor chip 210 is used as the reference position. Note that, when taking into consideration variations in pixel positions within the sensor chip 210, calculation may be performed by averaging in the sub-scanning direction.

As described above, according to the method shown in FIGS. 10 and 11, it is possible to calculate correction values for deviations in the main scanning direction and the sub-scanning direction within the reading device 201 (201a, 201b).

When calculating correction values for deviations in the main scanning direction and the sub-scanning direction in the reading device 201 (201a, 201b), reading of horizontal lines on the position reference member 202 and reading of vertical lines on the position reference member 202 are different. , whichever comes first.

Next, correction of the reading device 201 (201a, 201b) in the main scanning direction will be described in detail.

FIG. 12 is a diagram for explaining correction of the reading device in the main scanning direction. As shown in FIG. 12, by calculating the leading pixel position of each sensor chip 210 of the reading device 201 (201a, 201b), all pixel positions of the reading device 201 (201a, 201b) can be calculated.

A method of calculating the top pixel of the sensor chip 210 with an arbitrary chip number n will be described below. Let M be the number of pixels in each sensor chip 210 . Let N be the number of sensor chips 210 in the reading device 201 (201a, 201b).

First, a method for calculating the top pixel of the sensor chip 210 of the chip number n of the reading device 201a will be described.

Let A be the length of each sensor chip 210 corresponding to the vertical line of the position reference member 202b read by the sensor chip 210 of the chip number 1 and the sensor chip 210 of the chip number n of the reading device 201a, and the actual chip number 1. and the sensor chip 210 with the chip number n is the distance between the chips from the sensor chip 210 with the chip number 1 to the sensor chip 210 with the chip number n. is expressed by the following formula (1).
Sum of distances between chips = BA (1)

From the above, the corrected top pixel of the sensor chip 210 with the chip number n is the sum of the deviation of the inter-chip distance between the top pixel of the sensor chip 210 with the chip number n before correction and the sensor chip 210 with the chip number n. , as in the following equation (2).
First pixel after correction of sensor chip 210 with chip number n
= (M x (n-1)) + 1 + B-A (2)

Next, a method of calculating the leading pixel of the sensor chip 210 of the chip number n of the reading device 201b will be described.

First, the distance between the reading device 201a and the reading device 201b is obtained.

Let C be the interval between the vertical lines of the position reference member 202a read by the sensor chip 210 of the chip number N of the reading device 201a and the sensor chip 210 of the chip number 1 of the reading device 201b, and the actual chip number N of the reading device 201a. and the sensor chip 210 of chip number 1 of the reading device 201b is D, the distance between the reading device 201a and the reading device 201b is given by the following formula (3 )become that way.
Distance between reading device 201a and reading device 201b=DC (3)

In addition, the head pixel of the sensor chip 210 with the chip number n in the reading device 201b is as follows when considered in the same manner as in the reading device 201a.
First pixel after correction of sensor chip 210 with chip number n
= (M x (n-1)) + 1 + FE (4)
E: Length of each sensor chip 210 corresponding to the vertical line of the position reference member 202b read by the sensor chip 210 with chip number 1 and the sensor chip 210 with chip number n of the reading device 201b F: Actual chip number 1 between the vertical lines of the position reference member 202b corresponding to the sensor chip 210 of the chip number n

From the above, since the leading pixel of the sensor chip 210 of the chip number n of the reading device 201b is all pixels of the reading device 201a after correction+equation (3)+equation (4), the following equation (5) is obtained.
(M×N)+B'-A'+D-C+(M×(n-1))+1+FE (5)
A': Length of each sensor chip 210 corresponding to the vertical line of the position reference member 202b read by the sensor chip 210 with chip number 1 and the sensor chip 210 with chip number N of the reading device 201a B': Actual chip Distance between vertical lines of the position reference member 202b corresponding to the sensor chip 210 of number 1 and the sensor chip 210 of chip number N

From the above, the first pixel of the sensor chip 210 of the chip number n of the reading device 201a and the reading device 201b can be obtained by the formulas (2) and (5). Therefore, the m-th pixel of the sensor chip 210 of the chip number n of the reading device 201a is
Formula (2) + (m-1) (6)
The m-th pixel of the sensor chip 210 of the chip number n of the reading device 201b is
Formula (5) + (m-1) (7)
becomes.

Next, the correction of the scanning device 201 (201a, 201b) in the sub-scanning direction will be described in detail.

Correction of the entire sub-scanning position is a combination of FIGS. 9 and 11. FIG. At that time, the sub-scanning positions of the position reference member 202a and the right position reference member 202b, or between the position reference member 202a and the left position reference member 202b, may deviate due to assembly variations, so correction is required for that amount. becomes. A case will be described below in which the position reference member 202a and the right position reference member 202b are read by the reading device 201b and corrected. The same applies to the case where the position reference member 202a and the left position reference member 202b are read by the reading device 201a and corrected.

13A and 13B are diagrams for explaining correction in the sub-scanning direction of the reading device. (1) shown in FIG. 13A is the amount of sub-scanning deviation between the reading devices 201a and 201b, and (2) shown in FIG. 13A is the amount of sub-scanning deviation between the position reference members 202a and 202b. quantity. Also, N is the number of chips in each reading device 201 (201a, 201b), and n is an arbitrary chip number.

A method of obtaining the correction value of each chip sensor 210 of the reading device 201b when the sensor chip 210 of the chip number N of the reading device 201a is used as a reference will be described below. Note that the method for obtaining the correction value in the reading device 201a is as shown in FIG. 11, and therefore will be omitted.

The sensor chip 210 of the chip number N of the reading device 201a, the sensor chip 210 of the chip number 1 of the reading device 201b, the horizontal line of the position reference member 202a, the sensor chip 210 of the chip number 1 of the reading device 201b, the sensor chip of the chip number n. At 210, horizontal lines on the position reference member 202b are read while the rotating member 203 is rotated.

As shown in FIG. 13B, the horizontal line position read by the sensor chip 210 of the chip number N of the reading device 201a is set as the reference (0), and the position reference member 202a is set to the chip number 1 of the reading device 201b. If the position of the horizontal line read by the sensor chip 210 of the reading device 201b is defined as G, and the position of the horizontal line read by the sensor chip 210 of the chip number 1 of the reading device 201b is defined as H, the position of the position reference member 202a and the position reference member 202b is defined as H. The amount of sub-scanning deviation is
HG
is.

Further, when the horizontal line position of the position reference member 202b read by the sensor chip 210 of the chip number n of the reading device 201b is I, the correction amount for the sub-scanning position of the sensor chip 210 of the chip number n of the reading device 201b is:
I-(H-G)
becomes. HG is a deviation of the horizontal line position between the position reference members 202 (202a, 202b) serving as a reference, and is not a deviation of the reading device 201 (201a, 201b).

With the above method, even if the sub-scanning positions of the position reference member 202a and the position reference member 202b are deviated, it is possible to correct the deviation of the chip sub-scanning position of the reading apparatus as a whole.

Next, the flow of processing executed by the printing system 1 will be described.

Here, FIG. 14 is a flow chart schematically showing the flow of processing executed by the printing system 1. As shown in FIG. As shown in FIG. 14, the correction value calculator 112 first determines whether or not it is in the correction value calculation mode (step S1).

When the correction value calculation unit 112 determines that it is in the correction value calculation mode (Yes in step S1), the position reference member 202 (202a, 202b) is arranged at a position facing the reading device 201 (201a, 201b). A correction value calculation mode process for calculating a correction value is executed (step S2). On the other hand, when the correction value calculation unit 112 determines that it is not in the correction value calculation mode (No in step S1), the reading device 201 (201a, 201b) is positioned facing the reading background 205 and the recording paper is read. Mode processing is executed (step S3).

FIG. 15 is a flowchart schematically showing the flow of processing in the correction value calculation mode. As shown in FIG. 15, in the correction value calculation mode, the correction value calculation unit 112 first controls the motor control unit 111 to move the position reference member 202 (202a, 202b) to the position facing the reading device 201 (201a, 201b). (step S21).

Next, the correction value calculator 112 executes horizontal line reading (sub-scanning) of the position reference member 202 (202a, 202b) (step S22). More specifically, the correction value calculator 112 controls the motor controller 111 to rotate the position reference members 202 (202a and 202b), and controls the reading controller 110 to rotate the reading device 201 (201a and 201b). to read the horizontal line of the position reference member 202 (202a, 202b).

Next, the correction value calculation unit 112 calculates sub-scanning correction values between the reading devices 201 (201a and 201b) and within the reading devices 201 (201a and 201b), and stores them in a storage unit such as the HDD 18 for each calculation item ( step S23).

Next, the correction value calculator 112 executes vertical line reading (main scanning) of the position reference member 202 (202a, 202b) (step S24). More specifically, the correction value calculation unit 112 controls the motor control unit 111 to position the position reference member 202 (202a, 202b) facing the reading device 201 (201a, 201b), and controls the reading control unit 110. Then, the vertical lines of the position reference member 202 (202a, 202b) are read by the reading device 201 (201a, 201b).

Next, the correction value calculation unit 112 calculates main scanning correction values between the reading devices 201 (201a and 201b) and within the reading devices 201 (201a and 201b), and stores them in a storage unit such as the HDD 18 for each calculation item ( step S25).

With the above, the correction value calculation unit 112 ends the processing of the correction value calculation mode.

FIG. 16 is a flowchart schematically showing the flow of processing in read mode. As shown in FIG. 16, in the reading mode, the correction value calculation unit 112 first controls the motor control unit 111 to position the reading background 205 opposite the reading device 201 (201a, 201b) (step S31).

Next, the correction value calculation unit 112 controls the reading control unit 110 to read the edge of the conveyed recording paper and the image position recorded on the recording paper with the reading device 201 (201a, 201b) (step S32). ).

Next, the correction value calculator 112 corrects the reading result based on the correction value calculated in the correction value calculation mode (step S33).

If it is not the final recording sheet (No in step S34), the correction value calculation unit 112 repeats the processes of steps S32 and S33 for all target recording sheets.

When the correction value calculation unit 112 determines that the final recording sheet has been read (Yes in step S34), the processing in the reading mode ends.

As described above, according to the present embodiment, the position reference member 202a, which is the first position reference member for correcting the relative position between the reading devices, and the position reference member 202a in the reading device do not need to be long. By dividing it into the position reference member 202b, which is a second position reference member for position correction, and calculating the correction value for each, even if the reading range is expanded, the same degree of accuracy as that of a small-sized position reference member can be achieved. It can be realized at low cost.

A position reference member 202a, which is a first position reference member for correcting relative positions between reading devices, and a position reference member 202b, which is a second position reference member for correcting relative positions within a reading device. By clarifying the division of functions, the hardware configuration and control can be simplified, resulting in an inexpensive configuration.

(Second embodiment)
Next, a second embodiment will be described.

The second embodiment differs from the first embodiment in that a scanner unit used for MFP (Multifunction Peripheral/Printer/Product) is applied as a modified example of the medium position detection device 200 . Hereinafter, in the description of the second embodiment, the description of the same portions as those of the first embodiment will be omitted, and the portions different from those of the first embodiment will be described.

FIG. 17 is a perspective view showing the appearance of an image reading device 400 according to the second embodiment. The image reading device 400 is a modified example of the medium position detection device 200 and is a scanner unit used in MFPs and the like.

As shown in FIG. 17, the image reading device 400 has a contact glass 410 on the top surface. Contact glass 410 is formed in a substantially rectangular shape. The image reading apparatus 400 includes a reading device 201 (see FIG. 18) that moves in the sub-scanning direction b within the image reading apparatus 400 and reads linearly in the main scanning direction a. The reading device 201 reads an original placed on the contact glass 410 .

Further, the image reading device 400 further has a slit 411 . A glass 411 a is fitted in the slit 411 . The reading device 201 can read the position reference member 202 (see FIG. 18) through this slit 411 . Furthermore, a bridge 412 is formed between the contact glass 410 and the slit 411 .

In such a configuration, one short side of the contact glass 410 and one long side of the slit 411 shown in FIG. 17 are adjacent to each other with the bridge 412 interposed therebetween.

FIG. 18 is a side view partially showing the internal structure of the image reading device 400. As shown in FIG. 18A shows a state where the reading device 201 is positioned below the slit 411. FIG. 18B shows a state where the reading device 201 is positioned below the contact glass 410. FIG.

An automatic document feeder (ADF) 420 is provided above the image reading device 400 . ADF 420 is opened and closed when a document is placed on contact glass 410 . 18(a) and 18(b) show a state in which the ADF 420 is closed. As shown in FIGS. 18A and 18B, the ADF 420 has a position reference member 202 on the bottom surface of the ADF 420 at a position facing the slit 411 when the ADF 420 is closed.

In FIG. 18( a ), the reading device 201 is positioned below the glass 411 a fitted in the slit 411 . In FIG. 18( a ), the reading device 201 reads the position reference member 202 through the glass 411 a of the slit 411 .

Note that FIG. 18A shows the position reference member 202 formed on the bottom surface of the ADF 420 and facing the slit 411 when the DF 420 is closed. However, the position reference member 202 need not be provided on the ADF 420, and the slit 411 may be provided with the position reference member 202 instead of the glass 411a.

In FIG. 18B , the reading device 201 is positioned below the contact glass 410 and reads the document D placed on the contact glass 410 . At this time, the reading device 201 reads the document D while moving in the sub-scanning direction b.

In such a configuration, even if the reading device 201 is obliquely attached to the position reference member 202, the same problem as described in the first embodiment occurs. The problem can be solved by a method similar to that of the embodiment.

In addition, in each embodiment, as the reading device 201, a CIS, which is a so-called equal-magnification optical system, is applied, but the reading device 201 is not limited to this. For example, the reading device 201 may be a so-called reduction optical reading device that includes a light source, a plurality of reflecting members (mirrors), an imaging lens, a linear image sensor, and the like. If the device can detect the position of , it is possible to improve the position detection accuracy.

In each of the above-described embodiments, an example in which the image reading apparatus and the image forming apparatus of the present invention are applied to a printing system including an inkjet printing apparatus has been described. It can also be applied to a printing system including a printing device of the type.

Further, in each of the above embodiments, an example in which the image reading apparatus and the image forming apparatus of the present invention are applied to a printing system including a printing apparatus such as a commercial printing machine (production printing machine) has been described. It is applicable to any image forming device such as a multi-function device, a copier, a printer, a scanner device, a facsimile device, etc. that has at least two functions out of a copy function, a printer function, a scanner function, and a facsimile function. be able to.

Furthermore, in each of the above-described embodiments, an example in which the image reading apparatus of the present invention is applied to position detection in the field of image formation has been described. It can be applied to position detection applications in the field.

The image reading apparatus of the present invention can also be applied to a banknote reading apparatus that determines whether a banknote is printed in a correct position and shape for the purposes of banknote discrimination and counterfeit prevention.

1 image reading device, image forming device 105 print engine section 112 correction value calculation means 201 reading device 202 position reference member 202a first position reference member 202b second position reference member

JP-A-10-093787

Claims (5)

at least two reading devices arranged in a predetermined direction perpendicular to the direction in which the object to be read is conveyed;
a position reference member having a reference pattern serving as a reference for correcting the relative positions of each of the reading devices and between the reading devices, and moving relative to the reading device in a direction orthogonal to the predetermined direction;
correction value calculation means for calculating a correction value, which is a relative positional deviation for each of the reading devices and between the reading devices, based on reading results of the position reference member by the at least two reading devices;
with
The position reference member includes a first position reference member for correcting the relative position between the reading devices and a second position reference member for correcting the relative position within the reading device,
The reference patterns positioned at the edge of the first position reference member and the edge of the second position reference member, which are adjacent to each other, are positioned in the same reading area in the same reading device,
An image reading device characterized by: The first position reference member and the second position reference member are arranged on a straight line with respect to the predetermined direction,
2. The image reading apparatus according to claim 1, wherein: The correction value calculation means is
calculating a main scanning deviation between the reading devices based on the vertical lines of the reference pattern of the first position reference member;
calculating a sub-scanning deviation between the reading devices based on the horizontal line of the reference pattern of the first position reference member;
calculating a main scanning deviation in the reading device based on the vertical lines of the reference pattern of the second position reference member;
calculating a sub-scanning deviation in the reading device based on the horizontal line of the reference pattern of the second position reference member;
3. The image reading apparatus according to claim 1, wherein: a print engine,
an image reading device according to any one of claims 1 to 3;
An image forming apparatus comprising: at least two reading devices arranged in a predetermined direction perpendicular to the direction in which the object to be read is conveyed; An image reading method in an image reading apparatus comprising a position reference member that moves relative to a reading device in a direction perpendicular to the predetermined direction,
a correction value calculation step of calculating a correction value, which is a relative positional deviation for each of the reading devices and between the reading devices, based on reading results of the position reference member by the at least two reading devices;
The position reference member includes a first position reference member for correcting the relative position between the reading devices and a second position reference member for correcting the relative position within the reading device,
the reference patterns positioned at the edge of the first position reference member and the edge of the second position reference member, which are adjacent to each other, are positioned in the same reading area of the same reading device;
An image reading method characterized by:

Images