JP2000321028A - Thickness measuring device and thickness measuring method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To easily and accurately measure the thickness of a sheet, a film, a plate and the like by using a dot printing means and an image reading means. A thickness measuring device includes a dot forming element, a print head, a carriage, a print head drive control unit, and a thickness measurement object transport unit (51, 5).
2) printing means 1 and thickness measurement target 2
The image sensor 3 reads the thickness detection pattern DP composed of the outward path pattern DP1 and the return path pattern DP2 printed at 00, and the thickness detection pattern DP read by the image sensor is subjected to pattern analysis to calculate the thickness of the thickness measurement target. It is characterized by including a calculating means (pattern recognition program PRprg) and a display device 121 for outputting a thickness calculation result by the thickness calculating means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thickness measuring apparatus and a thickness measuring method having a simple structure capable of accurately measuring the thickness of a sheet or a film by combining printing and image reading.

[0002]

2. Description of the Related Art For example, ink jet printers in recent years tend to have higher resolution, and drive timings of nozzles formed in a print head in forward and backward paths are adjusted according to the thickness of a print medium. I have.
In general, an ink jet printer employs a BiD (bidy) driving method, that is, a method of driving nozzles formed in a print head in a forward path and a backward path of a carriage. In the BiD (by-die) driving method, unless the drive timings of the nozzles in the forward path and the return path are appropriately adjusted according to the print medium thickness, an image formed on the forward path (forward path image) and an image formed on the return path (forward image) (Return image), and the quality of the printed image is degraded. The quality degradation caused by the difference between the forward image and the backward image becomes more remarkable as the resolution becomes higher.

For this reason, it is normally preferable to allow a user to input a numerical value of the print medium thickness, and to adjust the above-described nozzle drive timing according to the input value.

[0004]

However, in practice, it is almost impossible for a user to have a print medium thickness measuring device, so it is not practical to "let the user input a print medium thickness numerically". It was previously thought.

[0005] In addition, ordinary people are not limited to print media,
You may want to know the thickness of a sheet, film, plate, or the like, but in reality, there is almost no special device such as a thickness measuring device owned by the general public. For this reason, it is common for ordinary people to not even have the idea of measuring the thickness of sheets, films, plates, and the like.

The present invention has been proposed in order to solve the above-mentioned problems. The present invention has been proposed in which the thickness of a sheet, film, plate or the like can be easily and accurately adjusted by using dot printing means and image reading means. Numerical measurement,
It is an object of the present invention to provide a thickness measuring device and a thickness running lowering method by a completely new method.

[0007]

SUMMARY OF THE INVENTION In an ink jet printer or a dot impact printer, as the thickness of the print medium changes, the paper gap (the distance between the nozzle or impact pin and the print medium) also changes. For example, in the case of an ink jet printer, if the driving timing of the nozzle is not adjusted according to the size of the paper gap, the trajectory of the ink droplet ejected from the nozzle deviates from the original trajectory. As a whole, the print quality is degraded in the main scanning direction (forward direction or backward direction).

The inventor of the present invention has determined the size of the paper gap,
We focused on the fact that there is a certain relationship between the size of the shift between the images of the forward and return paths. The present invention has been made based on the knowledge that the magnitude of the paper gap can be known by knowing the magnitude of the shift between the images of the forward and backward paths, and therefore the thickness of the print medium can be known.

The thickness measuring device of the present invention has a dot forming element, a print head, a carriage, a print head drive control section, a printing means including a thickness measuring object conveying means, and an image sensor. . The dot forming element is disposed with a gap between the dot forming element and a thickness measurement target (hereinafter, simply referred to as a “measurement target”), and is provided in the print head. Here, the dot forming element is a nozzle or an impact pin. A print head is mounted on the carriage and reciprocates linearly. This reciprocation moves at a constant speed in the print area. The print head drive control unit drives the dot forming element so that the thickness detection pattern is printed on the measurement object during the forward movement and the backward movement of the carriage. Further, the measuring object transporting means transports the measuring object at a predetermined feed pitch in the sub-scanning direction. It goes without saying that the reciprocating movement of the carriage and the driving of the dot forming elements are performed when the conveyance of the measurement target is stopped. The thickness detection pattern includes a forward path pattern and a return path pattern, and can be formed from a straight line parallel to the sub-scanning direction or a solid figure as described later. The image sensor reads the thickness detection pattern printed on the measurement target as image data.

[0010] The thickness measuring device of the present invention further has a thickness calculating means and a display device.
The thickness of the object to be measured is calculated by pattern analysis of the thickness detection pattern read by the image sensor, and the display device outputs the thickness calculation result calculated by the thickness calculation means as a numerical value on a screen.

When the thickness detection pattern is a straight line parallel to the sub-scanning direction formed during the forward movement and the backward movement of the carriage, these straight lines are formed on the forward movement or on the backward movement. Morphological features can be included. For example, a straight piece on the outward path and a straight piece on the return path are formed so as to be shifted from each other in the sub-scanning direction, or the color and type (for example, a solid line, a broken line, etc.) of the straight piece on the forward path and the straight piece on the return path are different. Thus, it is possible to detect whether the two straight lines are formed on the outward path or the return path. At this time, the thickness calculating means can measure the distance between the two straight lines by a well-known pattern analysis method, and can detect the thickness of the thickness detection target based on the measured value.

Further, the thickness detection pattern can be a solid figure partially overlapping each other. For example, when the thickness of the object to be measured is large, the overlap area between the solid figure formed on the outward path and the solid figure formed on the return path becomes large. A filled figure can be formed so that the overlapping area with the filled figure is reduced. In this case, the thickness calculating means can measure the area of the filled figure by a well-known pattern analysis method, and can detect the thickness of the thickness detection target based on the measured value.

In the thickness measuring apparatus of the present invention, the thickness calculating means may have a table or a function for obtaining the actual thickness of the object whose thickness is to be measured from the measurement result of the detection pattern. For example, with the platen gap (the distance between the stage supporting the thickness measurement medium and the print head) maximized, two reference samples of known thickness (one thick and one thin) The above-mentioned thickness detection pattern is printed, and the value of the detection pattern (the distance between the straight lines and the overlapping area of the filled figure with respect to the actual measurement target) is obtained and stored in a table. Then, for example, by interpolating between the numerical values indicated by the two detection patterns, the thickness of the unknown measurement target can be obtained in correspondence with the distance between the straight lines and the overlapping area of the filled figure. The number of reference samples is not limited to two but three
There can be more than one. These reference samples are
Attached to a thickness measuring device of the present invention sold as a product, the user can perform interpolation processing between numerical values indicated by a plurality of detection patterns and store the result in a table.
Further, prior to product shipment, interpolation processing between numerical values indicated by a plurality of detection patterns may be performed in a factory and stored in a table.

According to the thickness measuring method of the present invention, there are provided (a) a step of setting an object to be measured, and (b) a step of linearly reciprocating the dot forming element with a gap between the object and the object to be measured. (C) driving the dot forming element so that the thickness detection pattern is printed on the measurement target during the forward movement and the return movement of the dot formation element; and (d) the thickness detection pattern printed on the measurement target. (E) analyzing the thickness detection pattern input from the image to calculate the thickness of the measurement target, and (f) displaying and outputting the calculation result of the thickness of the measurement target. And

Also in the thickness measuring method of the present invention, the thickness detection pattern is a straight line formed during the forward movement and the backward movement of the dot forming element. In the step of calculating the thickness of the object to be measured, which includes the morphological features of the formed object, the distance between the straight lines is measured, and the thickness of the object to be detected can be detected based on the measured value. Further, the thickness detection pattern is a filled figure partially overlapped with each other formed during the forward movement and the backward movement of the carriage, and in the step of calculating the thickness of the measurement object, the area of the filled figure is measured. The thickness of the thickness detection target can be detected based on the measured value.

Further, in the thickness measuring method according to the present invention, in the step of calculating the thickness of the object to be measured, the thickness is measured with reference to a table or a function for obtaining the actual thickness of the object to be measured from the measurement result of the detection pattern. It can also be detected.

In the present invention, an ink jet printer can be used as the printing means, a scanner separate from the ink jet printer can be used as the image sensor, and a computer can be used as the thickness calculating means.
In this case, a detection pattern is printed on at least two reference samples by an ink-jet printer, and this is taken into a computer by a scanner, and the numerical value (the distance between the straight lines and the overlapping area of the filled figure described above) indicated by the detection pattern and The relationship between the reference sample and the actual thickness is stored in the computer. The computer prepares an interpolation program between the numerical values indicated by the detection patterns, for example, interpolates between the numerical values indicated by the detection patterns of the two reference samples, and displays a table or a table indicating the value of the detection pattern for an arbitrary thickness of the measurement target. Interpolation functions can be created. The user prints a detection pattern on an object of unknown thickness using the inkjet printer, captures the detection pattern into a computer using a scanner, and measures the thickness of the object of unknown thickness using the table or the interpolation function. can do. This measured value is displayed on a display device (display) of the computer.

The present invention can be applied to a printer with a scanner function as described in the embodiments. In this case, the thickness calculating means is incorporated in a printer with a scanner function, and the display device can also be provided in the printer.

If it is not desired to print the detection pattern on the object to be measured for thickness such as paper, a sheet holder or the like sandwiched between sheets of paper or the like made of a synthetic resin of a filer type should be used as the object for thickness measurement. Can be. In this case, the detection pattern is printed on the sheet holder. Then, the thickness of the paper or the like can be measured by subtracting the thickness of the sheet holder from the measured thickness of the measurement target. Since the detection pattern printed on the sheet holder made of a synthetic resin is usually easy to erase, the sheet holder can be used repeatedly.

[0020]

FIG. 1 shows an embodiment of a thickness measuring apparatus 100 to which an ink jet printer with a scanner is applied. The printing unit 1 includes a carriage 4 on which the print head 2 and the image sensor 3 are mounted, a transport mechanism 51 for intermittently transporting the measurement target 200 in the sub-scanning direction, a transport control unit 52 for controlling the transport mechanism 51, and the carriage 4. A carriage drive mechanism 61 for reciprocating in the main scanning direction and a carriage drive control unit 62 for controlling the carriage drive mechanism 61;
It includes a print head drive control unit 7 for driving (a dot forming element in the present invention), a storage device 8 having an EEPROM 81, an encoder unit 9 including a linear scale 91 and an optical detection unit 92, and a processing device 10. Further, a platen 11 is formed below the print head 2 and the image sensor 3, and a printer housing (not shown) is formed.
Is provided with a user interface 12.

The transport mechanism 51 includes a pulse motor 511, a transport roller 512, and the like.
The transport pulse MTP is sent to one pulse motor 511 to transport the measurement target 200 intermittently in the sub-scanning direction.

The carriage driving mechanism 61 includes a pulse motor 611, a timing belt 612, and the like. The carriage drive control unit 62 sends a carriage drive pulse CDP to the pulse motor 611 of the carriage drive mechanism 61, and while the conveyance of the measurement target 200 is stopped, the carriage 4
Is reciprocated at a constant speed in the print area.

The EEPROM 81 has a reference thickness setting program BTSprg and a pattern recognition program PRprg.
And the like, and the detection pattern DP and the table TBL. In the present embodiment, the detection pattern DP is composed of two sub-scanning direction straight pieces DP1 and DP2 slightly shifted from each other in the sub-scanning direction (see FIGS. 2A, 2B, 3A, and 3A described later). (B)). In addition, the table TBL includes “thickness” described later.
And the relationship between the “value” and “the numerical value indicated by the detection pattern” are written.

The user interface 12 includes a display 121, a reference thickness setting button 122, and a thickness measurement button 1.
23.

Hereinafter, the operation of the thickness measuring apparatus of FIG. 1 will be described in detail.

Although the maker of the thickness measuring apparatus 100 can write data in the table TBL prior to shipment from the factory, in this embodiment, the user uses the reference sample having a known thickness to store the data in the table TBL. Shall be written.

In this embodiment, in order to write data into the table TBL, two reference samples BS1, BS
2 is used. These reference samples BS1 and BS2 are
For example, the thickness is provided to the user by the manufacturer of the thickness measurement device 100, and one (BS1) is thick and the other (BS2) is thin.

When the user turns on the reference thickness setting button 122 of the user interface 12, the processing device 10
The reference thickness setting program BTSprg is started. The reference thickness setting program BTSprg allows the user to input the actual thickness of the reference sample BS1 via the user interface 12, and instructs the display 121 to set the reference sample BS1 to a feeder (not shown).
When the user sets the reference sample BS1 in the feeder according to the instruction, the reference sample BS1 includes
Two straight pieces DP1 and DP2 are printed. The position of the carriage (nozzle drive timing) when these linear pieces DP1 and DP2 are formed is arbitrary.
In addition, the position of the carriage when forming the straight piece DP1 may be the same as or may be apart from the position of the carriage when forming the straight piece DP1 (in the present embodiment, a fixed distance). L away).

FIG. 2A is a diagram showing the position of the carriage 4 and the trajectory of ink droplets when the linear pieces DP1 and DP2 are printed on the reference sample BS1.
(B) shows the print result of the straight pieces DP1 and DP2.

When the linear pieces DP1 and DP2 are printed, the reference thickness setting program BTSprg transports the reference sample BS1 in the reverse direction, and then transports the reference sample BS1 in the forward direction again, and sends the linear pieces DP1 and DP2 to the image sensor 3.
To read. Then, the reference thickness setting program BTSprg performs pattern analysis on the straight pieces DP1 and DP2 to determine the distance between the two straight pieces. The distance between the straight pieces DP1 and DP2 takes a positive or negative value.

The distance between the two straight lines does not need to be a standard unit such as “inch” or “millimeter”, but may be an arbitrary length (for example, the number of dot pitches depending on the resolution of the scanner). It can be.

The reference thickness setting program BTSprg allows the user to input the actual thickness also for the reference sample BS2, and instructs the setting of the reference sample BS2 to a feeder (not shown). Thereby, the reference sample BS2
, Two straight pieces DP1 and DP2 are printed. At this time, the position of the carriage when printing two straight pieces DP1 and DP2 is based on the reference sample BS.
1 is the same as the carriage position when the linear pieces DP1 and DP2 are printed. Reference thickness setting program BT
Sprg is the linear piece D for the reference sample BS1 as well.
P1 and DP2 are subjected to pattern analysis to determine the distance between the two straight-line pieces. FIG. 3 (A) shows a straight piece D on the reference sample BS2.
Carriage 4 when P1 and DP2 are printed
3B and the trajectory of the ink droplet. FIG. 3B shows the print results of the straight pieces DP1 and DP2. The positional relationship between the straight pieces DP1 and DP2 printed on the reference sample BS2 is the positional relationship between the straight pieces DP1 and DP2 printed on the reference sample BS1 (see FIGS. 2A and 2B).
Is reversed. That is, the distance between the straight pieces DP1 and DP2 shown in FIGS. 3A and 3B is negative.

The reference thickness setting program BTSprg is based on the actual thicknesses of the reference samples BS1 and BS2 and the distance between the straight pieces DP1 and DP2, and the thickness of the unknown measurement object is printed at this time. Each straight piece D
A table TBL is created by calculating the relationship between the predicted value of the distance between P1 and DP2.

An example of the contents of the table TBL is shown in FIG.
Shown in In FIG. 4, reference samples BS1 and BS2
Are shown in bold.

Next, the user sets the measurement target 2 whose thickness is unknown.
The process of measuring the thickness of the sheet No. 00 will be described with reference to the flowchart of FIG. First, the user presses the thickness measurement button 12 on the user interface 12.
When 3 is turned on, the processing device 10 starts the pattern recognition program PRprg (step S1). The pattern recognition program PRprg instructs the setting of the measurement target 200 on the feeder (not shown) via the display 121, and the user sets the measurement target 200 on the feeder according to the instruction (step S2). Thereafter, the nozzle 21 is driven, and two straight pieces DP1 and DP2 are printed on the measurement target 200 (Step S3). At this time, two straight pieces DP1 and DP2
Is the same as the carriage position when the linear pieces DP1 and DP2 are printed on the reference samples BS1 and BS2.

When the linear pieces DP1 and DP2 are printed, the pattern recognition program PRprg transports the measurement object 200 in the reverse direction, and then transports the measurement object 200 in the forward direction again. Reading is performed (step S4). Then, the pattern recognition program PRprg analyzes the pattern of the straight pieces DP1 and DP2 to determine the distance between the two straight pieces and obtains the table TB
L, the thickness of the measurement object corresponding to the distance between the two linear pieces is determined, and the measurement result of the thickness of the measurement object 200 is displayed on the display 1.
21 (step S5). Thereby, the user can know the thickness of the measurement target 200 as a numerical value such as “millimeter”.

As can be seen from the above embodiment, the measurement target 2
The measurement accuracy of the thickness of 00 depends on the resolution of the image sensor 3 but does not depend on the resolution of the encoder unit 9. Therefore, as a printing unit in the present invention, an ink jet printing mechanism having a relatively low resolution or a dot impact printing mechanism can be adopted.

In the above-described embodiment, an example in which the printing means 1 and the image sensor 3 are mounted on the carriage 4 has been described. However, a normal printer can be used as the printing means and an image scanner can be used as the image sensor. A computer system including a printer and an image scanner can be used as the thickness measuring device of the present invention.

In the above embodiment, the reference sample BS
Table T using two straight pieces BS1 and BS2 as
Although the BL has been created, the table TBL can be created with three or more straight pieces. Also, in the above embodiment. Although the thickness of the measurement target is determined with reference to the table TBL, the thickness of the measurement target may be determined by a function using the distance between the straight pieces DP1 and DP2 as an independent variable instead of the table TBL. Further, in the above embodiment, the reference sample BS is a straight piece, but two solid figures can be employed instead of the straight piece. In this case, for example, when the thickness of the measurement target is thin, the overlapping portion between the filled figure on the outward path and the filled figure on the return path becomes small (or becomes large), and when the thickness of the measurement object is large, the overlapping part becomes large. Set the position of the filled figure so that it becomes (or becomes smaller). Thus, the pattern recognition program PRprg can calculate the thickness to be measured by determining the area of the solid image read by the image scanner.

[0040]

According to the present invention, it is possible to easily and accurately measure the thickness of a sheet, a film, a plate, and the like by using the dot printing means and the image reading means.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a thickness measuring device showing one embodiment of the present invention.

FIG. 2A is a diagram showing a position of a carriage and a trajectory of an ink droplet when linear pieces DP1 and DP2 are printed on a reference sample BS1, and FIG.
FIG. 9 is a diagram illustrating print results of P1 and DP2.

FIG. 3A is a diagram showing a position of a carriage and a trajectory of an ink droplet when linear pieces DP1 and DP2 are printed on a reference sample BS2, and FIG.
FIG. 9 is a diagram illustrating print results of P1 and DP2.

FIG. 4 is a diagram illustrating an example of a table showing a relationship between a measurement target thickness and a distance between straight pieces DP1 and DP2.

FIG. 5 is a flowchart illustrating a process of measuring the thickness of a measurement target whose thickness is unknown.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printing means 2 Print head 3 Image sensor 4 Carriage 7 Print head drive control part 8 Storage device 9 Encoder unit 10 Processing unit 11 Platen 12 User interface 21 Nozzle 51 Transport mechanism 52 Transport control part 61 Carriage drive mechanism 62 Carriage drive control part 81 EEPROM 91 Linear scale 92 Optical detection unit 100 Thickness measurement device 121 Display 122 Print medium thickness selection button 123 Thickness measurement button 200 Measurement target 511 Pulse motor 512 Transport roller 611 Pulse motor 612 Timing belt TBL Table DP Detection pattern DP1, DP2 Linear piece BTSprg Reference thickness setting program PRprg Pattern recognition program

Claims (8)

[Claims] 1. A dot forming element arranged to have a gap between a thickness measuring object, a print head on which the dot forming element is formed, and a print head mounted with the print head and linearly arranged in a main scanning direction. A print head drive control unit that drives the dot forming element so that a thickness detection pattern is printed on the thickness measurement target during the forward movement and the return movement of the carriage; and A printing unit having an object transporting unit, and an image sensor that reads, as image data, a thickness detection pattern formed of a forward path pattern and a return path pattern printed on the thickness measurement target, and a thickness detection pattern read by the image sensor. Thickness calculation means for calculating the thickness of the thickness measurement object by pattern analysis of the And a display device for outputting a thickness calculation result by the thickness calculating means. 2. The thickness detection pattern is a straight line parallel to the sub-scanning direction formed during the forward movement and the backward movement of the carriage, and these straight lines are formed on the forward movement or formed on the backward movement. 2. The method according to claim 1, further comprising a morphological feature, wherein the thickness calculating unit measures the distance between the straight lines and detects the thickness of the thickness detection target based on the measured value. 3. Thickness measuring device. 3. The thickness detection pattern is a filled figure partially overlapped with each other, formed during a forward movement and a backward movement of a carriage, and wherein the thickness calculating means measures an area of the filled figure. The thickness measuring apparatus according to claim 1, wherein the thickness of the thickness detection target is detected based on the measured value. 4. The apparatus according to claim 2, wherein said thickness calculating means has a table or a function for obtaining an actual thickness of the thickness measurement target from a measurement result of the detection pattern.
3. The thickness measuring device according to 1. 5. A step of setting a thickness measurement target, wherein a gap is provided between said thickness measurement target and said thickness measurement target.
Linearly reciprocating the dot forming element; during the forward movement and the backward movement of the dot forming element,
Driving the dot forming element so that a thickness detection pattern is printed on the thickness measurement target; reading a thickness detection pattern including a forward pass pattern and a return pass pattern printed on the thickness measurement target as image data A step of calculating a thickness of the thickness measurement target by pattern-analyzing the thickness detection pattern input as an image, and a step of displaying and outputting a calculation result of the thickness of the thickness measurement target. 6. The thickness detection pattern is a straight line parallel to the sub-scanning direction formed during the forward movement and the backward movement of the dot forming element. In the step of calculating the thickness of the measurement target, the distance between the straight lines is measured, and the thickness of the thickness detection target is detected based on the measured value. The thickness measuring method according to claim 5, wherein 7. The method according to claim 7, wherein the thickness detection pattern is a filled figure partially overlapped with each other and formed during the forward movement and the backward movement of the carriage. Measuring the area of the object, and detecting the thickness of the thickness detection target based on the measured value.
The thickness measurement method described in 1. 8. The step of calculating the thickness of the object to be measured is characterized in that the thickness is detected with reference to a table or a function for obtaining the actual thickness of the object to be measured from the measurement result of the detection pattern. The thickness measuring method according to claim 6.