JP2003246498A - Printer, line sensor and computer system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a printer, a line sensor and a computer system for grasping the positions of the upper end or the lower end and the side edges of a printed body with simple constitution. <P>SOLUTION: This printer is provided with a printing head movable in a main scanning direction to form dots on a printed body; a light emitting means for emitting light; and a line sensor in which light receiving elements for receiving the light emitted by the light emitting means are linearly arrayed. The printer is constituted to detect the output value change of the light receiving elements made by intercepting the light emitted by the light emitting means, by the edge of the printed body. The line sensor is provided so that the array direction of the light receiving elements is oblique to the main scanning direction. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing device, a line sensor, and a computer system.

[0002]

BACKGROUND ART A color inkjet printer, which is a typical printing apparatus, is already well known. This color inkjet printer includes an inkjet print head that ejects ink from nozzles, and is configured to record an image, a character, or the like by landing an ink droplet on a printing paper, which is an example of a printing medium. There is.

The print head is supported by a carriage that is an example of a movable member that includes the print head and has a nozzle surface formed with nozzles facing the print sheet, and is supported along a guide member. And moves in the width direction of the printing paper (main scanning), and ink is ejected in synchronization with this main scanning. Further, in recent years, a color inkjet printer capable of so-called borderless printing, which prints on the entire surface of a printing paper, has become popular because of the fact that an output result of the same image as a photograph can be obtained. By the borderless printing, for example, it is possible to print by ejecting ink without margins on the four edges of the printing paper.

By the way, in order to perform printing accurately at the position where dots should be formed on the printing paper, it is necessary to accurately grasp the position of the printing paper. Then, as one procedure for realizing this, the printing apparatus grasps the positions of the edges of the printing paper such as the upper end, the side edge and the lower end of the printing paper. In particular, in the case of the borderless printing, printing is performed also on the edge of the printing paper, so it is particularly important to accurately grasp the position of the edge of the printing paper.

Although some methods have been proposed for grasping the position of the edge of the printing paper, a light receiving element such as a photodiode for receiving light emitted from a light emitting means such as a light emitting diode is linearly arranged. There is a method of using the line sensor arrayed in. That is, this is a method of grasping the position of the edge of the printing paper by emitting linear light from the light emitting means and detecting a change in the output value of the light receiving element due to the edge of the printing paper blocking the light.

However, since the line sensor is formed by arranging minute light receiving elements in a line, the direction of the edge of the printing paper (for example, assuming that the printing paper is not bent, the directions of the upper end and the lower end are It is parallel to the main scanning direction, and the side edges, that is, the left edge and the right edge are parallel to the paper feeding direction) and the arrangement direction of the light receiving elements provided in the line sensor is parallel, or very close to parallel. In this case, it may be very difficult to detect the change in the output value. In addition, when the direction of the edge of the printing paper and the array direction of the light receiving elements have such a relationship, in order to prevent the edge of the printing paper from passing past the light receiving elements immediately, the relative position Although a countermeasure such as slowing down the moving speed may be considered, there is a possibility that the control circuit becomes complicated due to such a countermeasure.

Therefore, while avoiding these problems,
There is an inconvenience that a plurality of line sensors must be prepared in order to grasp the positions of the upper end or the lower end of the printing paper and its side end.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to grasp the positions of the upper end or lower end of a printing medium and its side ends with a simple structure. Printing device, line sensor, and
It is about realizing a computer system.

[0009]

The present invention is mainly directed to a print head movable in the main scanning direction for forming dots on a printing medium, a light emitting means for emitting light, and a light emitting means for emitting light by the light emitting means. A line sensor in which light receiving elements for receiving the emitted light are arranged in a line, and the change of the output value of the light receiving element due to the end of the printing medium blocking the light emitted by the light emitting means. In the printing device for detecting the above, the line sensor is provided so that the arrangement direction of the light receiving elements is oblique with respect to the main scanning direction.

Other features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS At least the following will be made clear by the description in the present specification and the accompanying drawings.

A print head movable in the main scanning direction for forming dots on a printing medium, a light emitting means for emitting light, and a light receiving element for receiving the light emitted by the light emitting means. A line sensor arranged linearly, wherein the end of the object to be printed interrupts the light emitted by the light emitting means and detects a change in the output value of the light receiving element, The printing apparatus, wherein the line sensor is provided so that the arrangement direction is oblique to the main scanning direction.

Since the line sensor is provided so that the arrangement direction of the light receiving elements is oblique with respect to the main scanning direction, the positions of the upper end or the lower end of the printing medium and its side ends can be simplified. Can be grasped.

Further, ink may be ejected from the print head to form dots on the printing medium.

In the so-called ink jet type printing apparatus for printing by ejecting ink from the print head,
In particular, since high quality of the printing result is required, the merit of the above means becomes greater.

Further, the change in the output value of the light receiving element due to the end of the printing medium sent in a predetermined feeding direction blocking the light emitted by the light emitting means is detected, and the printing medium is stopped. And moving the light emitting means and the line sensor in the main scanning direction to detect a change in the output value of the light receiving element due to the light emitted by the light emitting means blocking the edge of the printing medium. May be

With this configuration, the device configuration of the printing apparatus can be simplified.

Further, a change in the output value of the light receiving element due to the upper end of the printing medium sent in a predetermined feeding direction blocking the light emitted by the light emitting means is detected, and the printing medium is stopped. And, the light emitting means and the line sensor are moved in the main scanning direction to detect a change in the output value of the light receiving element due to the light emitted by the light emitting means blocking the side edge of the printing medium. It is also possible to detect a change in the output value of the light receiving element due to the lower end of the printing medium sent in a predetermined feeding direction blocking the light emitted by the light emitting means.

In this way, the object of the present invention can be achieved most effectively.

Further, the light emitting means and the line sensor may be moved according to the movement of the print head.

With this configuration, the print head, the light emitting means, and the moving mechanism of the line sensor can be shared.

The light emitting means may be included in the line sensor.

This is desirable in that it is not necessary to prepare the light emitting means separately from the line sensor.

Further, printing may be performed on the entire surface of the printing medium.

When printing is performed on the entire surface of the printing medium, since the printing is also performed on the edge of the printing paper, it is necessary to accurately grasp the position of the edge of the printing paper. The benefits will be greater.

Further, it has a print head movable in the main scanning direction for forming dots on the printing medium, and a light emitting means for emitting light, and for receiving the light emitted by the light emitting means. A line sensor in which the light receiving elements are linearly arranged, and the change in the output value of the light receiving elements due to the end of the printing medium blocking the light emitted by the light emitting means is detected. In a printing device that performs printing by ejecting ink from the entire surface of the printing medium, the line sensor is provided so that the arrangement direction of the light receiving elements is oblique with respect to the main scanning direction. Detecting the change in the output value of the light receiving element due to the upper end of the printing medium sent in a predetermined feeding direction blocking the light emitted by the light emitting means, and stopping the printing medium. mark The line sensor is moved in the main scanning direction according to the movement of the head, and the light emitted by the light emitting means detects a change in the output value of the light receiving element due to blocking the side end of the printing object, A printing apparatus, which detects a change in an output value of the light receiving element caused by blocking a light emitted from the light emitting means by a lower end of the printing medium sent in a predetermined feeding direction.

By doing so, all the effects described above are exhibited, and the object of the present invention is most effectively achieved.

Further, in a line sensor which is provided in the printing apparatus and in which light receiving elements for receiving the light emitted by the light emitting means provided in the printing apparatus are linearly arranged,
The line sensor is provided in the printing device such that an array direction of the light receiving elements is oblique to a main scanning direction in which a print head provided in the printing device can move.

With this configuration, the positions of the upper end or the lower end of the printing medium and its side end can be grasped with a simple structure.

Further, a computer main body, a display device connectable to the computer main body, and a printing device connectable to the computer main body, the printing being movable in the main scanning direction for forming dots on an object to be printed. A head, a light emitting means for emitting light, and a line sensor in which light receiving elements for receiving the light emitted by the light emitting means are arranged in a line, and the end of the printing medium is the light emitting means. A printing device for detecting a change in an output value of the light receiving element due to blocking of light emitted by the line sensor, wherein the line sensor is provided so that an array direction of the light receiving elements is oblique with respect to the main scanning direction. A computer system comprising: a printing device characterized by being provided.

The computer system thus realized is superior to the conventional system as a whole system.

=== Example of Overall Configuration of Apparatus === FIG. 1 is a block diagram showing the configuration of a printing system as an example of the present invention. This printing system includes a computer 90 and a color inkjet printer 20 as an example of a printing device. The printing system including the color inkjet printer 20 and the computer 90 can also be called a “printing device” in a broad sense.
Although not shown, the computer 90, the color inkjet printer 20, a display device such as a CRT 21 or a liquid crystal display device, an input device such as a keyboard or a mouse, a drive device such as a flexible drive device or a CD-ROM drive device, or the like. , A computer system has been built.

In the computer 90, the application program 9 is executed under a predetermined operating system.
5 is working. A video driver 91 and a printer driver 96 are incorporated in the operating system, and print data PD to be transferred to the color inkjet printer 20 is output from the application program 95 via these drivers. Application program for retouching images 9
Reference numeral 5 performs desired processing on the image to be processed, and displays the image on the CRT 21 via the video driver 91.

When the application program 95 issues a print command, the printer driver 9 of the computer 90
6 receives the image data from the application program 95, and receives it from the color inkjet printer 20.
To print data PD to be supplied to. Inside the printer driver 96, a resolution conversion module 97, a color conversion module 98, a halftone module 99,
Rasterizer 100, user interface display module 101, UI printer interface module 102, color conversion lookup table LUT
And are provided.

The resolution conversion module 97 plays a role of converting the resolution of the color image data formed by the application program 95 into the print resolution. The image data whose resolution has been converted in this way is still image information composed of three color components of RGB. Color conversion module 98
Refers to the color conversion lookup table LUT,
For each pixel, the RGB image data is converted into multi-tone data of a plurality of ink colors that the color inkjet printer 20 can use.

The color-converted multi-tone data is, for example, 25
It has 6 gradation values. The halftone module 99 executes so-called halftone processing to generate halftone image data. The halftone image data is rearranged by the rasterizer 100 in the order of data to be transferred to the color inkjet printer 20, and output as final print data PD. Print data P
D includes raster data indicating the dot formation state during each main scan and data indicating the sub-scan feed amount.

User interface display module 1
01 has a function of displaying various user interface windows related to printing, and a function of receiving user input in those windows.

The UI printer interface module 102 has a function of interfacing between a user interface (UI) and a color ink jet printer. The user interprets a command instructed by the user interface and sends various commands COM to the color inkjet printer, or conversely, interprets the command COM received from the color inkjet printer and performs various displays on the user interface. .

The printer driver 96 realizes the function of transmitting and receiving various commands COM, the function of supplying the print data PD to the color ink jet printer 20, and the like. The program for realizing the functions of the printer driver 96 is supplied in the form recorded in a computer-readable recording medium. Examples of such a recording medium include a flexible disk, a CD-ROM, a magneto-optical disk, an IC card, a ROM cartridge, a punch card, a printed matter on which codes such as a bar code are printed, and an internal storage device (RAM, ROM, etc.) of a computer. memory)
Also, various computer-readable media such as an external storage device can be used. It is also possible to download such a computer program to the computer 90 via the Internet.

FIG. 2 shows a color ink jet printer 2.
It is a schematic perspective view which shows an example of the main structures of 0. The color inkjet printer 20 includes a paper stacker 22.
A paper feed roller 24 driven by a step motor (not shown), a platen 26, a movable carriage 28 having a print head for forming dots, a carriage motor 30, and a traction driven by the carriage motor 30. It comprises a belt 32 and a guide rail 34 for the carriage 28. Further, the carriage 28 is equipped with a print head 36 having a large number of nozzles and a line image sensor 29 as an example of a line sensor described in detail later.

The printing paper P is taken up by the paper feed roller 24 from the paper stacker 22 and moves on the surface of the platen 26 in the paper feed direction (hereinafter also referred to as the sub-scanning direction) as an example of the feed direction of the material to be printed. Sent. Carriage 28
Is pulled by the pulling belt 32 driven by the carriage motor 30 and moves along the guide rail 34 in the main scanning direction. The main scanning direction means two directions perpendicular to the sub scanning direction as shown in the figure. The paper feed roller 24 is also used for the paper feeding operation for supplying the printing paper P to the color inkjet printer 20 and the paper discharging operation for discharging the printing paper P from the color inkjet printer 20.

=== Configuration Example of Line Image Sensor ==
= FIG. 3 is a sectional view schematically showing an example of the line image sensor 29.

The line image sensor 29 is attached to the carriage 28, and has a case 2, a glass plate 3, and a light emitting section 38 as an example of a light emitting means including a light emitting diode, and a light emitting section circuit including the light emitting section 38. Board 4
a, a light receiving element 40 for receiving the light emitted by the light emitting means including a phototransistor, a light receiving element circuit board 4b having a plurality of the light receiving elements 40,
The reflector 8 and the lens array 9 are provided. A control chip (not shown) is also mounted on the circuit boards 4a and 4b.

The case 2 is made of synthetic resin, for example, and is formed in a relatively elongated box shape extending in a certain direction.

The glass plate 3 is mounted on the upper surface of the case 2 so as to close the upper opening of the case 2.

The light emitting section 38 serves as a light source, and is provided on the light emitting section circuit board 4a.

The reflector 8 efficiently guides a part of the light emitted from the light emitting portion 38 to a predetermined area on the surface of the glass plate 3 in the direction of the area with a high reflectance. It has the function of reflecting light. The light emitted from the light emitting portion 38 passes through the predetermined area on the surface of the glass plate 3 and does not exist with respect to the printing paper P facing the line image sensor 29 or at the facing position. In this case, the platen 26 is linearly irradiated. The lens array 9 has a plurality of SELFOC lenses held in a block-shaped lens holder. The lens array 9 includes a glass plate 3 and a light receiving element 40.
Is provided between the light receiving elements 40 and the printing paper P or the platen 26, and reflects the light passing through the glass plate 3 into a plurality of light receiving elements 40.

The plurality of light receiving elements 40 are arranged in a line on the light receiving element circuit board 4b. The light linearly applied to the printing paper P or the platen 26 is reflected by the printing paper P or the platen 26, and the reflected light is received by each of the plurality of light receiving elements 40 arranged on the line. It has become so. For example, in this embodiment, 152 light receiving elements 40 are arranged on a line, and the arrangement direction thereof coincides with the direction of penetrating the paper surface of FIG. The reflected light received by the light receiving element 40 is converted into an electric signal, and the magnitude of the electric signal is measured as an output value of the light receiving element 40 according to the intensity of the received reflected light.

In the above description, in order to obtain the intensity of the received reflected light, the magnitude of the electric signal is measured after converting the reflected light into an electric signal, but the present invention is not limited to this. Instead, it is only necessary to be able to measure the output value of the light receiving element 40 according to the intensity of the received reflected light.

=== Exemplary Configuration around Carriage === Next, the configuration around the carriage will be described. Figure 4
FIG. 3 is a diagram showing a configuration around a carriage 28 of the inkjet printer.

The ink jet printer shown in FIG.
A carriage 2 in which a paper feed motor (hereinafter, also referred to as a PF motor) 31 for feeding paper and a print head 36 for ejecting ink onto the print paper P are fixed and driven in the main scanning direction.
8, a carriage motor (hereinafter also referred to as a CR motor) 30 for driving the carriage 28, a linear encoder 11 fixed to the carriage 28, and a linear encoder code plate 12 having slits formed at predetermined intervals. ,
A rotary encoder 13 (not shown) for the PF motor 31
A platen 26 that supports the printing paper P, a paper feed roller 24 that drives the PF motor 31 to convey the printing paper P, a pulley 25 attached to the rotation shaft of the CR motor 30, and a pulley 25. And a tow belt 32.

Next, the linear encoder 11 and the rotary encoder 13 will be described. Figure 5
Linear encoder 11 mounted on carriage 28
It is explanatory drawing which showed the structure of.

The linear encoder 11 shown in FIG.
A light emitting diode 11a, a collimator lens 11b,
The detection processing unit 11c is provided. Detection processing unit 11c
Is a plurality of (for example, four) photodiodes 11d,
The signal processing circuit 11e and, for example, two comparators 11
It has fA and 11fB.

When the voltage VCC is applied to both ends of the light emitting diode 11a via a resistor, light is emitted from the light emitting diode 11a. This light is condensed into parallel light by the collimator lens 11b and the code plate 12 for the linear encoder is used.
Pass through. The linear encoder code plate 12 has a predetermined interval (for example, 1/180 inch (1 inch = 2.5
4 cm)) is provided with a slit.

The parallel light that has passed through the linear encoder code plate 12 enters each photodiode 11d through a fixed slit (not shown) and is converted into an electric signal. Four
The electric signal output from each photodiode 11d is processed in the signal processing circuit 11e, and the signal output from the signal processing circuit 11e is a comparator 11fA,
The comparison is performed at 11 fB, and the comparison result is output as a pulse. The pulses ENC-A and ENC-B output from the comparators 11fA and 11fB become the output of the linear encoder 11.

FIG. 6 is a timing chart showing the waveforms of the two output signals of the linear encoder 11 when the CR motor is rotating normally and when rotating reversely.

As shown in FIGS. 6 (a) and 6 (b),
In both cases of the forward rotation and the reverse rotation of the CR motor, the phases of the pulse ENC-A and the pulse ENC-B differ by 90 degrees. When the CR motor 30 is rotating normally, that is, when the carriage 28 is moving in the main scanning direction, the pulse ENC-A is 90 degrees more than the pulse ENC-B as shown in FIG. 6A. When the phase advances only by and the CR motor 30 rotates in the reverse direction, as shown in FIG.
The pulse ENC-A lags the phase of the pulse ENC-B by 90 degrees. Then, the pulse ENC-A and the pulse E
One cycle T of NC-B is equal to the time for which the carriage 28 moves in the slit interval of the linear encoder code plate 12.

Then, the rising edges and rising edges of the output pulses ENC-A and ENC-B of the linear encoder 11 are detected, the number of detected edges is counted, and the CR motor 30 is based on this count value.
The rotational position of is calculated. This count is "+" when one edge is detected while the CR motor 30 is rotating normally.
1 "is added, and when it is reversed," -1 "is added when one edge is detected. The period of each of the pulses ENC-A and ENC-B is the time from when one slit of the linear encoder code plate 12 passes through the linear encoder 11 to when the next slit passes through the linear encoder 11. They are equal and the phases of the pulse ENC-A and the pulse ENC-B differ by 90 degrees.
Therefore, the count value "1" of the above count corresponds to 1/4 of the slit interval of the linear encoder code plate 12. Thus, by multiplying the count value by 1/4 of the slit interval, the amount of movement of the CR motor 30 from the rotational position corresponding to the count value "0" can be obtained based on the multiplied value. At this time, the resolution of the linear encoder 11 is 1/4 of the slit interval of the linear encoder code plate 12.

On the other hand, in the rotary encoder 13 for the PF motor 31, the rotary encoder code plate 14 is the PF.
It has the same configuration as the linear encoder 11 except that it is a rotating disk that rotates in accordance with the rotation of the motor 31, and outputs two output pulses ENC-A and ENC-B. The amount of movement of the PF motor 31 can be calculated.

=== Example of Electrical Configuration of Color Inkjet Printer === FIG. 7 is a block diagram showing an example of the electrical configuration of the color inkjet printer 20. The color inkjet printer 20 includes a buffer memory 50 that receives a signal supplied from a computer 90, an image buffer 52 that stores print data, a system controller 54 that controls the overall operation of the color inkjet printer 20, and a main memory 56. And an EEPROM 58. The system controller 54 further includes a main scanning drive circuit 6 for driving the carriage motor 30.
1 and a sub-scanning drive circuit 62 for driving the paper feed motor 31.
And a head drive circuit 63 that drives the print head 36,
Light emitting unit 38 of line image sensor 29, light receiving element 40
The line image sensor control circuit 65 for controlling the above, the linear encoder 11 described above, and the rotary encoder 13 described above are connected. The line image sensor control circuit 65 also includes an electric signal measuring unit 66 for measuring an electric signal converted from the reflected light received by the light receiving element 40.

The print data transferred from the computer 90 is temporarily stored in the buffer memory 50. In the color inkjet printer 20, the system controller 54 reads necessary information from the print data from the buffer memory 50, and based on this, the main scanning drive circuit 61, the sub-scanning drive circuit 62, the head drive circuit 63, etc. A control signal is sent to it.

The image buffer 52 stores print data of a plurality of color components received by the buffer memory 50. The head drive circuit 63 is the system controller 5
The print data of each color component is read from the image buffer 52 in accordance with the control signal from the No. 4, and the nozzle array of each color provided in the print head 36 is driven in accordance with this.

=== Example of Nozzle Arrangement of Print Head === FIG. 8 is an explanatory diagram showing a nozzle arrangement on the lower surface of the print head 36. The print head 36 has a black nozzle row and a color nozzle row, which are arranged on a straight line along the sub-scanning direction. In the present specification, the “nozzle row” is also referred to as a “nozzle group”.

There are 18 black nozzle rows (indicated by white circles).
It has zero nozzles # 1 to # 180. These nozzles # 1 to # 180 are arranged at a constant nozzle pitch k · D along the sub-scanning direction. Here, D is a dot pitch in the sub-scanning direction, and k is an integer. The dot pitch D in the sub-scanning direction is the main scanning line (raster line)
Is equal to the pitch. Hereinafter, the integer k representing the nozzle pitch k · D will be simply referred to as “nozzle pitch k”. The unit of the nozzle pitch k is "dot", which means the dot pitch in the sub-scanning direction.

In the example of FIG. 8, the nozzle pitch k is 4 dots. However, the nozzle pitch k can be set to an arbitrary integer.

The color nozzle row is a yellow nozzle group Y.
(Shown by white triangles), a magenta nozzle group M (shown by white squares), and a cyan nozzle group C (shown by white diamonds). In this specification, the nozzle group for chromatic color ink is also referred to as a “chromatic color nozzle group”. Each chromatic color nozzle group has 60 nozzles # 1 to # 60. The nozzle pitch of the chromatic color nozzle group is the same as the nozzle pitch k of the black nozzle row. The nozzles of the chromatic color nozzle group are arranged at the same sub-scanning positions as the nozzles of the black nozzle row.

During printing, ink droplets are ejected from each nozzle while the print head 36 moves together with the carriage 28 in the main scanning direction at a constant speed. However, depending on the printing method, not all nozzles are always used, and only some nozzles may be used.

=== First Embodiment === Next, a first embodiment of the present invention will be described with reference to some drawings. In the present embodiment, by using the line image sensor 29 described above, the upper end of the printing paper P,
The side edge and the lower edge are sequentially grasped.

<< Understanding Upper Edge Position >> First, an example in which the upper edge position of the printing paper is grasped using the line image sensor 29 will be described with reference to FIGS. 9 and 10. FIG. 9 is a diagram schematically showing the positional relationship among the print head 36, the line image sensor 29, and the print paper P.
6 is a flowchart for explaining an example of grasping the upper end position of the printing paper by using the line image sensor 29.

First, the user gives an instruction to print using the application program 95 or the like (step S2). When the application program 95 that receives this instruction issues a print command, the computer 9
The printer driver 96 of 0 receives the image data from the application program 95, and converts it into the print data PD including the raster data indicating the dot formation state at each main scan and the data indicating the sub-scan feed amount. Further, the printer driver 96 supplies the print data PD to the color inkjet printer 20 together with various commands COM. The color inkjet printer 20 receives these by the buffer memory 50 and then transmits them to the image buffer 52 or the system controller 54.

Further, the user can instruct the user interface display module 101 that the size of the printing paper P and the borderless printing should be performed. The user's instruction is the user interface display module 10
1 and sent to the UI printer interface module 102. The UI printer interface module 102 interprets the instructed instruction,
The command COM is transmitted to the color inkjet printer 20. The color inkjet printer 20 receives the command COM by the buffer memory 50,
It is transmitted to the system controller 54.

The color ink jet printer 20 is based on the command transmitted to the system controller 54.
The sub-scanning drive circuit 62 drives the paper feed motor 31 to feed the printing paper P (step S4).

Next, the system controller 54 drives the CR motor 30 by the main scanning drive circuit 61 to move the carriage 28 to a predetermined position (hereinafter, also referred to as the first position).
To perform positioning (step S6). And
The amount of movement of the CR motor 30 from the reference position is obtained based on the output pulse of the linear encoder 11, and the amount of movement, in other words, the first position of the carriage 28 is stored (step S8).

Further, the system controller 54 has the line image sensor 2 provided on the carriage 28 positioned by the line image sensor control circuit 65.
9 to control the light emitting portion 3 of the line image sensor 29.
8 emits light toward the platen 26 (step S1)
0).

As described above, the light emitted from the light emitting portion 38 passes through a predetermined area on the surface of the glass plate 3 and is linearly irradiated to the platen 26 facing the line image sensor 29. It The light radiated on the line is reflected by the platen 26, and the reflected light is received by each of the plurality of light receiving elements 40 arranged on the line.

The line image sensor 29 includes a plurality of light receiving elements 4 provided in the line image sensor 29.
So that the array direction of 0s is oblique to the main scanning direction,
It is provided on the carriage 28. In the present embodiment, as shown in FIG. 9, the line image sensor 2 is arranged so that the angle formed by the arrangement direction and the main scanning direction is 45 degrees.
9 is provided. Therefore, the light emitted on the line forms an angle of 45 degrees with the main scanning direction. The angle is not limited to 45 degrees.

Next, when the printing paper P is further fed by the paper feed motor 31 as shown in FIGS. 9A and 9B, the printing paper P is eventually fed as shown in FIG. 9B. The upper end blocks the light emitted from the light emitting unit 38 (step S12). At this time, since the incident destination of the light emitted from the light emitting unit 38 changes from the platen 26 to the printing paper P, the magnitude of the electric signal which is the output value of the light receiving element 40 of the line image sensor 29 which receives the reflected light. The size changes. Then, the magnitude of the electric signal is measured by the electric signal measuring unit 66, and it is detected that the upper end of the printing paper P has passed the light.

Further detailed description will be added with reference to FIG. FIG. 11 is a diagram showing a positional relationship between the printing paper P and the plurality of light receiving elements 40.

In FIG. 11, the arrangement direction of the plurality of light receiving elements 40 is 45 degrees with respect to the main scanning direction. Further, in order to facilitate understanding, the number of light receiving elements 40 is 16, and the light receiving elements 40 are drawn in an enlarged scale as compared with the printing paper P.

Further, the printing paper P may be bent (obliquely) fed or fed, and in this case, strictly speaking, the most advanced one in the paper feeding direction is the upper end. It is the left end or the right end. In the present embodiment, the right end of the upper end (located at the lower left in the figure) is fed first in the paper feed direction.

The output value of each light receiving element 40 differs depending on where the received light is reflected. That is, the magnitude of the electric signal which is the output value of the light receiving element 40 which receives the light reflected by the printing paper P and the magnitude of the electric signal which is the output value of the light receiving element 40 which receives the light reflected by the platen 26 are different. In FIG. 11, each light receiving element 40
Is indicated by a square, the light receiving element 40 that receives the light reflected by the printing paper P is a white square block, and the light receiving element 40 that receives the light reflected by the platen 26 is a shaded square. Shown in blocks.

In FIG. 11A, the first to third blocks from the top are the light receiving elements 40 which receive the light reflected by the printing paper P, and the fifth to 16th blocks are reflected by the platen 26. The light receiving element 40 receives the emitted light. The fourth block, which is a shaded area between the two, is a part of the printing paper P and a part of the platen 26.
The light receiving element 40 that receives the light reflected by
The magnitude of the electric signal which is the output value of the light receiving element 40 is
It is between the 1st to 3rd blocks and the 5th to 16th blocks.

FIG. 11B is a diagram showing the positional relationship between the printing paper P and the plurality of light receiving elements 40 when the printing paper P is further fed from the state of FIG. 11A. In the figure, the 1st to 8th blocks from the top are the light receiving elements 40 that receive the light reflected by the printing paper P, and the 10th to 16th blocks are the light receiving elements that receive the light reflected by the platen 26. 40, and the ninth block is the light receiving element 40 that receives the light reflected by the printing paper P and the platen 26.

In the state of FIG. 11A, the system controller 54 obtains the movement amount of the PF motor 31 from the reference position based on the output pulse of the rotary encoder 13, and the movement amount is expressed in other words. Then, the feed amount of the printing paper P is stored (step S14).

Further, even in the state of FIG. 11B, the system controller 54 uses the rotary encoder 13
The movement amount of the PF motor 31 from the reference position is calculated based on the output pulse of
The feed amount of is stored (step S16).

Next, the system controller 54 obtains one of the left end and the right end of the upper end that is fed first in the paper feed direction in the paper feed direction.

A method for obtaining such a position will be described with reference to FIG. FIG. 12 is a diagram for explaining an example of a method for obtaining a position in the paper feeding direction, which is one of the left end and the right end of the upper end of the printing paper P, which is fed first in the paper feeding direction.

Two straight lines rising to the right shown by solid lines in the figure represent the upper end of the printing paper P. In addition, one straight line descending to the right, which is also shown by a solid line in the figure, represents a plurality of light receiving elements 40 arranged on the line.

The left end of the upward-sloping straight line shown in the figure is the upper end of the right end of the printing paper P (hereinafter, also referred to as the upper right end).
The right end of the straight line represents the left end of the upper end of the printing paper P (hereinafter, also referred to as the upper left end). The right and left are reversed with respect to the straight line and the upper end of the printing paper P because the paper feeding direction is from the upper side to the lower side in the drawing.

Further, a straight line rising to the right (hereinafter also referred to as a straight line X) shown above in the drawing and a straight line descending to the right (hereinafter also referred to as a straight line Z) showing a plurality of light receiving elements 40 arranged linearly. 11A corresponds to FIG. 11A, and a plurality of light receiving elements 40 arranged linearly with a straight line rising to the right (hereinafter, also referred to as a straight line Y) shown below in the drawing. The relative relationship of the downward-sloping straight line shown corresponds to FIG. Therefore, at the intersection A of the upward-sloping straight line and the downward-sloping straight line shown in the upper part of the figure, the fourth light receiving element 40 from the above is located, and the rightward rising line shown in the lower part of the figure. At the intersection B of the straight line and the straight line descending to the right, the ninth light receiving element 40 from the above is located.

Further, as shown in the figure, a point C is an intersection point when a line is drawn from the point A to a straight line Y in parallel with the paper feeding direction. Further, an intersection point when a line is drawn from the point B to a straight line connecting the points A and C in parallel with the main scanning direction is defined as a point D.

First, since the relative position of the first position of the carriage 28 stored in step S8 and the ninth light receiving element 40 located at the intersection B with the carriage 28 from the top is known, the main information of the point B from both information is known. The position a in the scanning direction can be obtained. Note that the numerical value a is a value based on the position of the upper right end of the printing paper P in the main scanning direction for convenience, but is not limited to this and may be another position.

Further, paying attention to the paper feeding direction, the difference p between the positions of points A and C on the drawing is as it is, the feeding amount of the printing paper P stored in step S14 and the printing paper P stored in step S16. It represents the difference from the feed amount. Therefore,
The difference p can be obtained from the numerical values stored in steps S14 and S16.

Further, the distance b of the straight line AB shown in the figure is known because it is the distance from the fourth light receiving element 40 from the top to the ninth light receiving element 40 from the top.

Next, from the numerical values a, b, and p, the position in the paper feeding direction of either the left end or the right end of the upper end that is fed first in the paper feeding direction (upper right end in this embodiment) is determined. Ask. As shown in the drawing, the position is represented by, for example, a difference q in the paper feeding direction relative to the point B.

Since the angle formed by the straight line AC and the straight line AB is 45 degrees as described above, AD = DB = b / √2. Therefore, as is clear from the figure, DC = p−b / √2. If the angle between straight line BD and straight line BC is θ, tan
Since θ = DC / DB, tan θ is a numerical value p and a numerical value b
Can be expressed as

Also, as is clear from the figure, q = a × ta
Since there is a relationship of nθ, the numerical value q to be obtained can be represented by the numerical values a, b and p.

In this way, steps S8, S14,
From the numerical value stored in S16 and the known numerical value, the position in the paper feeding direction of one of the left end and the right end of the upper end that is fed first in the paper feeding direction (in the present embodiment, the upper right end) is obtained. (Step S18). That is, according to the above procedure, the upper end of the printing paper P can be precisely grasped using the line image sensor 29.

Next, as shown in FIGS. 9B and 9C, the system controller 54 operates the sub-scanning drive circuit 6
The paper feed motor 31 is driven by 2 to feed the print paper P so that the upper right end of the left end and the right end of the upper end, which is advanced in the feeding direction, reaches a predetermined position (step S20). ).

In this embodiment, as shown in FIG. 9C, in order to perform borderless printing, the upper right end is the uppermost portion of the print head (the uppermost portion in the paper feeding direction, but in FIG. 9). Indicates the nozzle located at the bottom) and feeds the print paper P to reach the nozzle. The paper feed amount in this case can be obtained, for example, from the distance in the paper feed direction between the uppermost part of the print head and the light receiving element 40 and the above-mentioned numerical value q.

The nozzle arrangement of the print head has already been described with reference to FIG. 8. However, in order to facilitate understanding, in FIG. 9, it is composed of a row of nozzle groups, and A print head provided with eight nozzles is shown as an example.

After the paper feed, the system controller 54 ejects ink from the print head to start borderless printing on the print paper P (step S22).

In the above, in steps S14 and S16, the amount of movement of the PF motor 31 from the reference position is obtained, and the amount of movement is stored as the feed amount of the printing paper P, and the difference p But step S1
The reference position for obtaining the movement amount of the PF motor 21 in 6 is set as the position of the PF motor 31 in step S14.
You may obtain said numerical value p.

Further, in the above, the first position is the predetermined position, but it may be any position. When the first position is the predetermined position, the subsequent procedure of storing the first position, that is, step S8 may be omitted.

In the above, at the intersection A,
Although the fourth light receiving element 40 from the top is located and the ninth light receiving element 40 from the top is located at the intersection B, these are not necessarily the fourth or ninth light receiving element 40. No need. Moreover, it is not necessary to determine in advance which number light receiving element 40 is located at each intersection. These matters also apply to the case of grasping the side end position and the lower end position, which will be described later, as they are.

<<< Understanding Side Edge Position >>> Next, an example in which the side edge position of the printing paper is grasped using the line image sensor 29 will be described with reference to FIGS. 13 and 14.
FIG. 13 shows the print head 36 and the line image sensor 29.
FIG. 14 is a diagram schematically showing the positional relationship between the printing paper P and the printing paper P, and FIG. 14 is a flowchart for explaining an example of grasping the side edge position of the printing paper using the line image sensor 29.

As described above, the system controller 54
Starts ejecting ink from the print head to start borderless printing on the printing paper P (step S22). The system controller 54 drives the PF motor 31 by the sub-scanning drive circuit 62 to feed the printing paper P, and drives the CR motor 30 by the main-scanning drive circuit 61 to move the carriage 28 to perform main printing. To do.

Then, along with the actual printing, in other words, with the movement of the carriage 28 in the main scanning direction, the side edge position of the printing paper is grasped. The system controller 54 controls the line image sensor 29 provided on the carriage 28 by the line image sensor control circuit 65, and emits light from the light emitting section 38 of the line image sensor 29 toward the platen 26 (step S).
24).

Further, as described above, the light emitted from the light emitting section 38 passes through a predetermined region on the surface of the glass plate 3 and faces the line image sensor 29.
6 is irradiated linearly. The light radiated on the line is reflected by the platen 26, and the reflected light is received by each of the plurality of light receiving elements 40 arranged on the line.

Further, as described above, the line image sensor 29 is provided on the carriage 28 so that the arrangement direction of the plurality of light receiving elements 40 provided in the line image sensor 29 is oblique with respect to the main scanning direction. ing.
In this embodiment, as shown in FIG. 13, the line image sensor 29 is provided so that the angle formed by the arrangement direction and the main scanning direction is 45 degrees. Therefore, the light emitted on the line forms an angle of 45 degrees with the main scanning direction.

Next, as shown in FIGS. 13A and 13B, the system controller 54 drives the CR motor 30 by the main scanning drive circuit 61 to move the carriage 28. Eventually, as shown in FIG. 13B, the light emitted from the light emitting unit 38 blocks the side edge of the printing paper P (step S26). At this time, since the incident destination of the light emitted from the light emitting unit 38 changes from the platen 26 to the printing paper P, the magnitude of the electric signal which is the output value of the light receiving element 40 of the line image sensor 29 which receives the reflected light. The size changes. Then, the magnitude of the electric signal is measured by the electric signal measuring unit 66, and it is detected that the side edge of the printing paper P has passed the light.

Further detailed description will be added with reference to FIG. FIG. 15 is a diagram showing a positional relationship between the printing paper P and the plurality of light receiving elements 40.

In FIG. 15, the arrangement direction of the plurality of light receiving elements 40 is 45 degrees with respect to the main scanning direction. Further, in order to facilitate understanding, the number of light receiving elements 40 is 16, and the light receiving elements 40 are drawn in an enlarged scale as compared with the printing paper P.

Further, the printing paper P may be bent (obliquely) fed or fed. In the present embodiment, the right edge as the side edge of the printing paper P is shown in FIG. In this figure, since the paper feed direction is set to the direction shown in the figure, the left side of the straight line descending to the right is the region related to the platen 26, and
The right side is an area related to the printing paper P.

The output value of each light receiving element 40 differs depending on where the received light is reflected. That is, the magnitude of the electric signal which is the output value of the light receiving element 40 which receives the light reflected by the printing paper P and the magnitude of the electric signal which is the output value of the light receiving element 40 which receives the light reflected by the platen 26 are different. In FIG. 15, each light receiving element 40
Is indicated by a square, the light receiving element 40 that receives the light reflected by the printing paper P is a white square block, and the light receiving element 40 that receives the light reflected by the platen 26 is a shaded square. Shown in blocks.

In FIG. 15A, the first to tenth blocks from the top are the light receiving elements 40 that receive the light reflected by the platen 26, and the twelfth to sixteenth blocks are reflected by the printing paper P. The light receiving element 40 receives the emitted light. The diagonal line between the two is 11
The second block represents the light receiving element 40, which is partly the printing paper P and partly receives the light reflected by the platen 26. The magnitude of the electric signal which is the output value of the light receiving element 40 is It is between the 1st to 10th blocks and the 12th to 16th blocks.

FIG. 15B is a diagram showing the positional relationship between the print paper P and the plurality of light receiving elements 40 when the carriage 28 is further moved in the main scanning direction from the state of FIG. 15A. In the figure, the first to fourth blocks from the top are the light receiving elements 4 that receive the light reflected by the platen 26.
0, the 6th to 16th blocks are the light receiving elements 40 that receive the light reflected by the printing paper P, and the 5th block are the light receiving elements that receive the light reflected by the printing paper P and the platen 26. 40.

In the state of FIG. 15A, the system controller 54 obtains the movement amount of the CR motor 30 from the reference position based on the output pulse of the linear encoder 11, and the movement amount is expressed in other words. Carriage 28
The position (hereinafter, also referred to as the second position) is stored (step S28).

Further, also in the state of FIG. 15B, the system controller 54 obtains the moving amount of the CR motor 30 from the reference position based on the output pulse of the linear encoder 11, and the moving amount is In other words, the carriage 2
The position 8 (hereinafter, also referred to as the third position) is stored (step S30). Next, the system controller 54 obtains the inclination of the printing paper P.

A method for obtaining such an inclination will be described with reference to FIG. FIG. 16 is a diagram for explaining an example of a method for obtaining the inclination of the printing paper P.

Two parallel straight lines shown by solid lines in the figure represent a plurality of light receiving elements 40 arranged on the lines. Further, another straight line (hereinafter, also referred to as a straight line X2) different from the above two straight lines also shown by the solid line in the drawing represents the right end of the printing paper P.

Further, of the two straight lines parallel to each other, the straight line shown on the left side of the drawing (hereinafter, also referred to as straight line Y2)
The straight line X2 and the straight line X2 correspond to each other in FIG. 15 (a), and the straight line X2 and the straight line shown on the right side of the two mutually parallel straight lines in the figure.
The relative relationship of is corresponding to FIG. Therefore, at the intersection A of the straight line X2 and the straight line Y2, the eleventh light receiving element 40 from the above is located, and the straight line X2
At the intersection B of the line Z2 and the line Z2, the fifth light-receiving element 40 from the above is located.

Further, as shown in the figure, a point C is an intersection point when a line is drawn from the point A to a straight line Z2 in parallel with the main scanning direction. Further, an intersection point when a line is drawn from the point B to the straight line Y2 in parallel with the paper feeding direction is set as a point D.

First, the distance a between AC can be obtained from the second position of the carriage 28 stored in step S28 and the third position of the carriage 28 stored in step S30.

Further, the distance b of the straight line BC shown in the figure is known since it is the distance from the fifth light receiving element 40 from the top to the eleventh light receiving element 40 from the top.

Next, the inclination of the printing paper P is obtained from the numerical values a and b. As shown in the figure, the inclination is represented by, for example, an angle θ formed by the straight line BD and the straight line BA.

Since the angle formed by the straight line CA and the straight line CB is 45 degrees as described above, ∠CBA + ∠CAB = 135 degrees.
Also, from the law of sine, a / sin (∠CBA) = b / s
in (∠ CAB) is established.

Therefore, ∠CBA can be solved,
As is clear from the figure, θ = 45 degrees-∠CBA, so
Finally, θ can be represented by numerical values a and b.

In this way, steps S28 and S30
Printing paper P from the values stored in
Is calculated (step S32).

The inclination thus obtained is obtained by, for example, moving the carriage 28 in the main scanning direction to print the start position of ink ejection to the printing paper P and the end position of ink ejection. It is effectively used to determine each nozzle of the head 36. As described above, since the plurality of nozzles of the print head 36 are arranged in the paper feeding direction, when the print paper P is tilted, the start position and the end position are slightly different for each nozzle. is there.

Note that, in the above, the light receiving element 4 due to the emitted light blocking the right end of the side edges of the printing paper P
Although it was decided to detect the change in the output value of 0, the printing paper P
It is also possible to detect a change in the output value of the light receiving element 40 due to blocking the left end of the side edges of the light receiving element 40. It may be detected.

<<< Understanding Bottom Position >>> Next, an example in which the line image sensor 29 is used to find the lower end position of the printing paper will be described with reference to FIGS. 17 and 18. FIG.
FIG. 17 shows the print head 36 and the line image sensor 29.
19 is a diagram schematically showing the positional relationship between the printing paper P and the printing paper P, and FIG. 18 is a flowchart for explaining an example in which the line image sensor 29 is used to grasp the lower end position of the printing paper.

As described above, the system controller 54
Is the carriage 2 while feeding the print paper P in the paper feed direction.
8 is moved in the main scanning direction, ink is ejected from the print head 36 provided on the carriage 28 to perform borderless printing (step S22). The sub-scan drive circuit 62 drives the paper feed motor 31 to feed the print paper P in the paper feed direction, and the main scan drive circuit 61 drives the carriage motor 30 to move the carriage 28 in the main scan direction.
The ink is ejected from the print head 36 by driving
The print head 36 is driven by the head drive circuit 63, respectively.

The color ink jet printer 20 continuously carries out the operation of step S22. However, for example, when the paper feed amount of the printing paper P reaches a predetermined amount, the following operation is carried out.

First, the system controller 54 drives the CR motor 30 by the main scanning drive circuit 61 to move the carriage 28 to a predetermined position (hereinafter, also referred to as a fourth position).
To position (step S36). Then, based on the output pulse of the linear encoder 11, C
The movement amount of the R motor 30 from the reference position is obtained, and the movement amount, in other words, the fourth position of the carriage 28 is stored (step S38).

Further, the system controller 54 is provided with the line image sensor 2 provided on the carriage 28 positioned by the line image sensor control circuit 65.
9 to control the light emitting portion 3 of the line image sensor 29.
Light is emitted from 8 toward the printing paper P (step S4).
0).

As described above, the light emitted from the light emitting portion 38 passes through a predetermined area on the surface of the glass plate 3 and is applied to the printing paper P facing the line image sensor 29.
It is irradiated linearly. Then, the light irradiated on the line is reflected by the printing paper P, and the reflected light is received by each of the plurality of light receiving elements 40 arranged on the line.

Further, as described above, the line image sensor 29 is provided on the carriage 28 so that the arrangement direction of the plurality of light receiving elements 40 provided in the line image sensor 29 is oblique with respect to the main scanning direction. Has been. In the present embodiment, as shown in FIG. 17, the line image sensor 29 is provided so that the angle formed by the arrangement direction and the main scanning direction is 45 degrees. Therefore, the light emitted on the line forms an angle of 45 degrees with the main scanning direction.

Next, when the print paper P is further fed by the paper feed motor 31 as shown in FIGS. 17 (a) and 17 (b), the print paper P is eventually fed as shown in FIG. 17 (b). The lower end blocks the light emitted from the light emitting unit 38 (step S42). At this time, the incident destination of the light emitted from the light emitting unit 38 is the printing paper P from the platen 2
6, the magnitude of the electric signal, which is the output value of the light receiving element 40 of the line image sensor 29 that receives the reflected light, changes. Then, the magnitude of the electric signal is measured by the electric signal measuring unit 66, and it is detected that the lower end of the printing paper P has passed the light.

Further detailed description will be added with reference to FIG. FIG. 19 is a diagram showing the positional relationship between the printing paper P and the plurality of light receiving elements 40.

In FIG. 19, the arrangement direction of the plurality of light receiving elements 40 is 45 degrees with respect to the main scanning direction. Further, in order to facilitate understanding, the number of light receiving elements 40 is 16, and the light receiving elements 40 are drawn in an enlarged scale as compared with the printing paper P.

Further, the printing paper P may be bent (obliquely) fed or fed, and in this case, strictly speaking, only the bottom end is fed in the paper feeding direction. It is the left end or the right end. In the present embodiment, the left end of the lower end (located at the upper right in the figure) is fed farthest in the paper feed direction.

The output value of each light receiving element 40 differs depending on where the received light is reflected. That is, the magnitude of the electric signal which is the output value of the light receiving element 40 which receives the light reflected by the printing paper P and the magnitude of the electric signal which is the output value of the light receiving element 40 which receives the light reflected by the platen 26 are different. In FIG. 19, each light receiving element 40
Is indicated by a square, the light receiving element 40 that receives the light reflected by the printing paper P is a white square block, and the light receiving element 40 that receives the light reflected by the platen 26 is a shaded square. Shown in blocks.

In FIG. 19A, the first to third blocks from the top in the figure are the light receiving elements 40 that receive the light reflected by the platen 26, and the fifth to 16th blocks are reflected by the printing paper P. The light receiving element 40 receives the emitted light. The fourth block, which is a shaded area between the two, is a part of the printing paper P and a part of the platen 26.
The light receiving element 40 that receives the light reflected by
The magnitude of the electric signal which is the output value of the light receiving element 40 is
It is between the 1st to 3rd blocks and the 5th to 16th blocks.

FIG. 19B is a diagram showing the positional relationship between the printing paper P and the plurality of light receiving elements 40 when the printing paper P is further fed from the state of FIG. 19A. In this figure, the first to eighth blocks from the top are the platen 26.
Is the light receiving element 40 that receives the light reflected by the printing paper P, the tenth to sixteenth blocks are the light receiving elements 40 that receive the light reflected by the printing paper P, and the ninth block is the printing paper P and the platen 26. The light receiving element 40 receives the light reflected by.

In the state of FIG. 19A, the system controller 54 obtains the movement amount of the PF motor 31 from the reference position based on the output pulse of the rotary encoder 13, and the movement amount is expressed in other words. Then, the feed amount of the printing paper P is stored (step S44).

Also in the state of FIG. 19B, the system controller 54 uses the rotary encoder 13
The movement amount of the PF motor 31 from the reference position is calculated based on the output pulse of
The feed amount is stored (step S46).

Next, the system controller 54 obtains the position in the paper feed direction of either the left end or the right end of the lower end that is fed later in the paper feed direction (lower left end in the present embodiment) (step). S48). The position can be obtained by a method similar to the above-described method for obtaining the position in the one of the left end and the right end of the upper end that is fed first in the paper feed direction. That is, according to the above procedure, the lower end of the printing paper P can be precisely grasped by using the line image sensor 29.

Although the fourth position is the predetermined position in the above, it may be an arbitrary position. Further, when the fourth position is the predetermined position, the subsequent procedure of storing the fourth position, that is, step S38 may be omitted.

The procedure for sequentially grasping the upper end, the side end, and the lower end of the printing paper P using the line image sensor 29 has been described above based on the embodiment.

As described in the background art section, since the line image sensor 29 is an array of minute light receiving elements 40, the direction of the edge of the printing paper P and the light received by the line image sensor 29. When the arrangement directions of the elements 40 are parallel or extremely close to each other, it may be very difficult to detect the change in the output value of the light receiving element 40 described above. Therefore, in order to grasp the positions of the upper end or the lower end of the printing paper P and its side end while avoiding these problems, a plurality of line image sensors 29 are used.
The inconvenience of having to prepare is generated.

Therefore, by providing the line image sensor 29 so that the arrangement direction of the light receiving elements 40 is inclined with respect to the main scanning direction, the upper end or the lower end of the printing paper P and its side end can be structured with a simple structure. The position of can be grasped.

A program for performing the above processing is stored in the EEPROM 58, and the program is executed by the system controller 54.

=== Other Embodiments === The printing apparatus and the like according to the present invention have been described based on one embodiment, but the embodiments of the present invention described above facilitate understanding of the present invention. However, the present invention is not limited thereto. The present invention can be modified and improved without departing from the spirit of the invention, and it goes without saying that the present invention includes equivalents thereof.

Although the printing paper has been described as an example of the printing object, a film, a cloth, a thin metal plate or the like may be used as the printing object. Further, a computer main body, a display device connectable to the computer main body, the printer according to the above-described embodiment connectable to the computer main body, an input device such as a mouse and a keyboard, and a flexible disk drive provided as necessary. Device and C
A computer system having a D-ROM drive device can also be realized, and the computer system realized in this way is superior to the conventional system as a whole system.

The printer according to the above-described embodiment may have some of the functions or mechanisms of the computer main body, the display device, the input device, the flexible disk drive device, and the CD-ROM drive device. For example, the printer is configured to include an image processing unit for performing image processing, a display unit for performing various displays, and a recording medium attaching / detaching unit for attaching / detaching a recording medium recording image data captured by a digital camera or the like. Good.

Although the color ink jet printer has been described in the above embodiment, the present invention can be applied to a monochrome ink jet printer and also to a printer other than the ink jet system. INDUSTRIAL APPLICABILITY The present invention is generally applicable to a printing apparatus that prints on an object to be printed, for example, a facsimile apparatus or a copying machine.

However, in a so-called ink jet type printing apparatus which prints by ejecting ink from the print head, a high quality of the printing result is particularly required, and therefore the merit of the above means becomes greater. Further, in the above embodiment, in the case of grasping the upper end or the lower end of the printing paper, the output value of the light receiving element due to the edge of the printing paper sent in the predetermined feeding direction blocking the light emitted by the light emitting unit When detecting the change and grasping the side edge of the printing paper,
The printing paper is kept stationary, and the light emitting unit and the line image sensor are moved in the main scanning direction to change the output value of the light receiving element due to the light emitted by the light emitting unit blocking the edge of the printing paper. Although the detection is performed, the invention is not limited to this. For example, regardless of which edge of the printing paper is grasped, only the light emitting unit and the line image sensor are moved, or only the printing paper is moved. Then, the above detection may be performed.

However, in the latter case, there arises a disadvantage that a mechanism for moving the light emitting portion, the line image sensor and the printing paper in both the main scanning direction and the sub scanning direction is required. Therefore, the above embodiment is more preferable in that the device configuration of the color inkjet printer can be simplified.

Further, in the above embodiment, the change of the output value of the light receiving element due to the upper end of the printing paper fed in the predetermined feeding direction blocking the light emitted by the light emitting portion is detected, and the printing paper is stopped. And, by moving the light emitting unit and the line image sensor in the main scanning direction, the change in the output value of the light receiving element due to the light emitted by the light emitting unit blocking the side edge of the printing paper, Although it has been decided to detect the change in the output value of the light receiving element due to the lower end of the printing paper sent in the predetermined feeding direction blocking the light emitted by the light emitting unit, the present invention is not limited to this, for example, The detection may be performed only on the upper end and the side edge of the printing paper, or the detection may be performed only on the lower end and the side edge of the printing paper.

However, the above-described embodiment is more advantageous in that the object of the present invention is most effectively achieved by performing the above-mentioned detection for all of the upper end, the side end, and the lower end of the printing paper. desirable.

In the above embodiment, the light emitting section and the line image sensor move according to the movement of the print head. However, the present invention is not limited to this. The light emitting unit and the line image sensor may be separately movable in the main scanning direction.

However, by doing so, the above-described embodiment is more preferable in that the moving mechanism of the print head, the light emitting portion and the line image sensor can be shared.

Further, in the above-mentioned embodiment, the light emitting section is provided in the line image sensor, but the present invention is not limited to this, and, for example,
Separate devices such as a light emitting device and a light receiving device may be configured.

However, by doing so, the above embodiment is more preferable in that it is not necessary to prepare the light emitting portion separately from the line image sensor.

In the above embodiment, borderless printing is performed, but the invention is not limited to this.

However, in the case of borderless printing, since the printing is also performed on the edge of the printing paper, it is necessary to accurately grasp the position of the edge of the printing paper. Further, in the above embodiment, the change in the output value of at least two light receiving elements is detected regardless of whether the upper edge, the side edge, or the lower edge of the printing paper is grasped, but the present invention is not limited to this. However, the change in the output value of only one light receiving element may be detected.

[0168]

According to the present invention, it is possible to realize a printing device, a line sensor, and a computer system for grasping the positions of the upper end or the lower end of a printing medium and its side ends with a simple structure.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a configuration of a printing system as an example of the present invention.

FIG. 2 is a schematic perspective view showing an example of a main configuration of a color inkjet printer 20.

FIG. 3 is a sectional view schematically showing an example of a line image sensor 29.

FIG. 4 is a diagram showing a configuration around a carriage 28 of the inkjet printer.

FIG. 5 is an explanatory view schematically showing a configuration of a linear encoder 11 attached to a carriage 28.

FIG. 6 is a timing chart showing waveforms of two output signals of the linear encoder 11 at the time of forward rotation and reverse rotation of the CR motor.

7 is a block diagram showing an example of the electrical configuration of the color inkjet printer 20. FIG.

FIG. 8 is an explanatory diagram showing a nozzle array on the lower surface of the print head.

9 is a diagram schematically showing the positional relationship among the print head 36, the line image sensor 29, and the print paper P. FIG.

FIG. 10 is a flowchart for explaining an example in which the line image sensor 29 is used to grasp the upper end position of printing paper.

FIG. 11 is a diagram showing a positional relationship between the printing paper P and the plurality of light receiving elements 40.

FIG. 12 is a diagram for explaining an example of a method of obtaining a position in the one of the left end and the right end of the upper end of the printing paper P, which is fed first in the paper feed direction.

FIG. 13 is a print head 36 and a line image sensor 29.
FIG. 6 is a diagram schematically showing the positional relationship between the print sheet P and the print sheet P.

FIG. 14 is a flowchart for explaining an example of grasping a side edge position of printing paper by using a line image sensor 29.

FIG. 15 is a diagram showing a positional relationship between a print sheet P and a plurality of light receiving elements 40.

16 is a diagram for explaining an example of a method for obtaining the inclination of the printing paper P. FIG.

FIG. 17 is a print head 36 and a line image sensor 29.
FIG. 6 is a diagram schematically showing the positional relationship between the print sheet P and the print sheet P.

FIG. 18 is a flow chart for explaining an example of grasping the lower end position of the printing paper by using the line image sensor 29.

FIG. 19 is a diagram showing a positional relationship between the printing paper P and the plurality of light receiving elements 40.

[Explanation of symbols]

2 Case 3 Glass plate 4a Light emitting part circuit board 4b Light receiving element circuit board 8 Reflector 9 Lens array 11 Linear encoder 12 Linear encoder code plate 13 Rotary encoder 14 Rotary encoder code plate 20 Color inkjet printer 21 CRT 22 Paper Stacker 24 Paper Feed Roller 25 Pulley 26 Platen 28 Carriage 29 Line Image Sensor 30 Carriage Motor 31 Paper Feed Motor 32 Traction Belt 34 Guide Rail 36 Print Head 38 Light Emitting Unit 40 Light Receiving Element 50 Buffer Memory 52 Image Buffer 54 System Controller 56 Main Memory 58 EEPROM 61 Main scanning drive circuit 62 Sub-scanning drive circuit 63 Head drive circuit 65 Line image sensor control circuit 66 Electrical signal measuring unit 9 0 computer 91 video driver 95 application program 96 printer driver 97 resolution conversion module 98 color conversion module 99 halftone module 100 rasterizer 101 user interface display module 102 UI printer interface module

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2C056 EB36 EB46 EC11 EC66 FA10                       HA58                 2C058 AB17 AC07 AC11 AD01 AE02                       GB05 GB13 GB30                 3F048 AA05 AB01 BA05 BB10 CC01                       DA08 DC15 EB37

Claims (10)

[Claims] 1. A print head movable in the main scanning direction for forming dots on a printing medium, a light emitting unit for emitting light, and a light receiving unit for receiving the light emitted by the light emitting unit. A line sensor in which elements are arranged in a line, and a printing device that detects a change in an output value of the light receiving element due to an edge of the object to be printed blocking light emitted by the light emitting means, A printing apparatus, wherein the line sensor is provided so that an arrangement direction of elements is oblique to the main scanning direction. 2. The printing apparatus according to claim 1, wherein ink is ejected from the print head to form dots on the printing medium. 3. The printing device according to claim 1, wherein an output of the light receiving element is obtained by blocking the light emitted by the light emitting means by an end of the printing medium sent in a predetermined feeding direction. The change in the value is detected, the printing medium is stopped, and the light emitting means and the line sensor are moved in the main scanning direction, so that the light emitted by the light emitting means blocks the edge of the printing medium. A printing apparatus, which detects a change in the output value of the light receiving element due to the above. 4. The printing apparatus according to claim 3, wherein a change in the output value of the light receiving element caused by blocking the light emitted by the light emitting means by the upper end of the printing medium sent in a predetermined feeding direction is performed. Detecting, by stopping the printing medium, and moving the light emitting means and the line sensor in the main scanning direction, the light emitted by the light emitting means blocks the side edge of the printing medium. Detecting a change in the output value of the light receiving element, and detecting a change in the output value of the light receiving element due to the lower end of the printing medium sent in a predetermined feeding direction blocking the light emitted by the light emitting means. Characteristic printing device. 5. The printing apparatus according to claim 3 or 4, wherein the light emitting unit and the line sensor move in accordance with movement of the print head. 6. The printing apparatus according to claim 1, wherein the light emitting unit is provided in the line sensor. 7. The printing device according to claim 1, wherein printing is performed on the entire surface of the printing medium. 8. A print head movable in the main scanning direction for forming dots on a printing medium, and a light emitting means for emitting light, for receiving light emitted by the light emitting means. A line sensor in which the light receiving elements are linearly arranged, and the change in the output value of the light receiving elements due to the end of the printing medium blocking the light emitted by the light emitting means is detected. In a printing apparatus that performs printing by ejecting ink from the entire surface of the printing medium, the line sensor is provided so that the arrangement direction of the light receiving elements is oblique with respect to the main scanning direction. Detecting the change in the output value of the light receiving element due to the upper end of the printing medium sent in a predetermined feeding direction blocking the light emitted by the light emitting means, and stopping the printing medium, and printing It said line sensor in accordance with the movement of the head is moved in the main scanning direction,
Detecting a change in the output value of the light receiving element due to the light emitted by the light emitting means blocking the side edge of the printing material, the lower end of the printing material sent in a predetermined feeding direction is detected by the light emitting means. A printing apparatus, which detects a change in an output value of the light receiving element due to blocking of emitted light. 9. A line sensor, which is provided in a printing apparatus and in which light-receiving elements for receiving light emitted by a light-emitting means provided in the printing apparatus are linearly arranged, wherein the arrangement direction of the light-receiving elements is A line sensor provided in the printing device so that a print head provided in the printing device is inclined with respect to a movable main scanning direction. 10. A computer main body, a display device connectable to the computer main body, and a printing device connectable to the computer main body, the printing being movable in a main scanning direction for forming dots on an object to be printed. A head, a light emitting means for emitting light, and a line sensor in which light receiving elements for receiving the light emitted by the light emitting means are arranged in a line, and the end of the printing medium is the light emitting means. A printing device for detecting a change in an output value of the light receiving element due to blocking of light emitted by the line sensor, wherein the line sensor is provided so that an array direction of the light receiving elements is oblique to the main scanning direction. A computer system comprising: a printing device characterized by being provided.