JP2004237533A - Printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printer having a function for measuring sharpness in which quantitative quality control (QC) of sharpness can be carried out easily at the installation site. <P>SOLUTION: The printer capable of recording a two-dimensional image on a recording material comprises a pattern generating means generating at least a test pattern for measuring the sharpness, a density measuring means consisting of a light source for illuminating a recording image being outputted and a photosensor, and a means for outputting the measurements from the measuring means. Sharpness can be grasped quantitatively by a CTF measuring system, or the like, in this printer. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technical field of various printers such as a thermal recording method and a photothermography. More specifically, the present invention has a sharpness measurement function, and quantitative management (image quality control, The present invention relates to a printer capable of performing QC).
[0002]
[Prior art]
Conventionally, in the medical field, various diagnostic image acquisition devices using X-rays and the like have been used. X-ray imaging devices, CR (Computed Radiography) devices, CT (Computed Tomography) Apparatuses, MRI (magnetic resonance imaging) apparatuses, etc. have come to practical use.
[0003]
Medical image information acquired by these apparatuses is reproduced as a hard copy on a recording material such as a film by a printer and used for medical diagnosis by a specialist.
A medical diagnosis using such an image is usually performed by using a monochrome (black and white) image and viewing a fine structure based on a difference in density of the image. For this reason, medical diagnostic images are required to have a sufficiently high sharpness.
[0004]
Therefore, it is necessary to perform the printer QC so as to always maintain a constant quality by paying more attention to the sharpness of medical diagnostic images output from the printer than other characteristics.
[0005]
Conventionally, with regard to the sharpness of the above-described image, a method of measuring the output image using, for example, a microdensitometer has been adopted, but this requires a large measuring device and requires a large installation place. Or the measurement operation is complicated, and there is a problem that it is not suitable for the measurement at the installation site (hospital etc.).
[0006]
Various evaluation methods have been proposed for the image quality of the image from the image output device. For example, Patent Literature 1 uses means for calculating a spatial frequency component using at least one of density information, lightness information, and chromaticity information of an image to be evaluated, and uses the spatial frequency of the visual system as the calculation result. An image quality evaluation method that performs correction according to characteristics is disclosed.
[0007]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-39486
[Problems to be solved by the invention]
In other words, the image sharpness is preferably measured quantitatively by CTF (Contrast Transfer Function) measurement or the like, but for the reasons described above, in practice, it is actually replaced by visual inspection. There are many points ahead.
[0009]
The present invention has been made in view of the above circumstances, and its object is to solve the problems in the prior art, and to provide a sharpness measurement function so that the installation location can be easily quantitatively related to sharpness. It is an object of the present invention to provide a printer that can perform easy management (QC).
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a printer according to the present invention is a printer configured to be able to record a two-dimensional image on a recording material by recording means, and generates a pattern for generating at least a test pattern for measuring sharpness. A sharpness measurement test generated by the pattern generation means, and a density measurement means comprising an illumination light source and an optical sensor for illuminating the output recorded image, and a measurement result output means by the measurement means A pattern is recorded on the recording material, the sharpness is measured by relatively moving the recording material and the concentration measuring means in a one-dimensional direction, and the measurement result is output to the output means. To do.
[0011]
Here, the density measuring unit measures a sharpness measurement test pattern recorded on the recording material in at least one of a main scanning direction by the recording unit or a sub-scanning direction orthogonal thereto. Is preferred.
[0012]
In the printer according to the present invention, it is preferable that both the transmissive recording material and the reflective recording material can be selectively used as the density measuring means.
[0013]
In the printer according to the present invention, it is preferable that a management function of the measurement result by the measurement unit is provided in addition to the above units. Further, it is preferable to use a CTF measurement pattern as the test pattern for sharpness measurement, but the present invention is not necessarily limited to this.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0015]
FIG. 1 is a schematic side view showing a configuration of a thermal recording type printer having a sharpness measuring function according to an embodiment of the present invention.
The printer 10 shown in FIG. 1 performs thermal image recording on a thermal recording material such as a light-transmissive thermal recording film (hereinafter simply referred to as film) F having a predetermined size such as a half-cut size. , A transport unit 16, a recording unit 20 that records a thermal image on the film F by the thermal head 18, a tray 22 that receives the recorded film, and a sharpness measurement function unit 24.
[0016]
The film F is a transparent PET (polyethylene terephthalate) or the like as a support, and a thermal recording layer is formed on one side thereof. For example, the film F is a laminate of about 100 predetermined units, Housed in magazine 26.
The magazine 26 has a lid 28, is inserted into the apparatus through an insertion port formed in the printer 10, and is loaded into a predetermined position of the loading unit 12 by a known means using a guide, a stopper, or the like. The
[0017]
The transport unit 16 has a function of taking out the film F from the magazine 26 loaded in the loading unit 12 and transporting the film F to the recording unit 20. The transport unit 16 uses a sucker 30 that sucks the film F and a pair of transport rollers. 32, a conveyance guide 34, a cleaning roller pair 36, an opening / closing mechanism (not shown), and the like.
[0018]
First, an outline of the basic operation of the printer 10 according to this embodiment configured as described above will be described.
In the printer 10, when an instruction to start recording is issued, the above-described opening / closing mechanism opens the cover 28 of the magazine 26, and the suction cup 30 sucks one film F, takes it out from the magazine 26, and feeds a pair of transport rollers 32. To supply. The film F supplied to the transport roller pair 32 is transported to the cleaning roller pair 36 while being guided by the transport guide 34, and the recording unit is configured to remove dust and dirt attached to the recording surface by the upper cleaning roller in the drawing. 20 is sent.
[0019]
The recording unit 20 includes the thermal head 18, the platen roller 38, the conveyance guide 40 and the discharge roller pair 44 a and 44 b, the drive control unit 46, a cooling fan (not shown) for the thermal head 18, and the like. ing.
[0020]
The thermal head 18 includes a heat storage layer (glaze layer), a heating element arranged in one direction (main scanning direction, a direction perpendicular to the paper surface in FIG. 1) composed of a heating resistor and an electrode, a glaze composed of a protective layer, and the like. This is a known thermal head having a thermal head main body having a heat sink and a heat sink fixed to the thermal head main body. Each heating element of the thermal head 18 is driven, for example, by pulse modulation in accordance with the recorded image by the drive control unit 46.
[0021]
Here, as a recorded image (or a part thereof), a test pattern for sharpness measurement generated by the above-described pattern generating means is recorded according to a predetermined recording method (details will be described later).
The platen roller 38 rotates at a predetermined speed while holding the film F in a predetermined position, sandwiches the film F together with the thermal head 18 (the glaze thereof), and has a predetermined recording speed in the sub-scanning direction orthogonal to the main scanning direction. Carry in.
[0022]
The film F transported from the cleaning roller pair 36 is transported in the sub-scanning direction while being sandwiched between the platen roller 38 and the thermal head 18 (the glaze thereof) and scanned by the thermal head 18 (heating element array). . In parallel with this conveyance, the drive control unit 46 drives each heating element of the thermal head 18 according to the image data, thereby heating the heating resistor, and the film F is heated accordingly to develop color. , An image is recorded.
The film F on which the image is recorded is conveyed by the discharge roller pair 44a and 44b and discharged to the tray 22 as a hard copy.
[0023]
The sharpness measuring function unit 24 manages (checks) the sharpness using the test pattern for measuring the sharpness recorded on the film F in the printer 10, and includes the sharpness control unit 48 and the sharpness control unit 48. Degree measuring means 50.
[0024]
The sharpness control unit 48 performs recording / measurement of the test pattern for sharpness measurement generated by the above-described pattern generating means on the film F and controls various processes according to the measurement results. When the operation is performed, an instruction is given to the drive control unit 46 as necessary, and the test pattern is recorded by the thermal head 18, or the measurement result of the recorded test pattern is received, and processing is performed accordingly. It is a part.
[0025]
The sharpness measuring means 50 measures the test pattern recorded on the film F being conveyed between the discharge roller pair 44a and 44b when performing QC related to the sharpness, and the illumination light source 50a. And the optical sensor 50b.
Here, since the light transmissive film F is the measurement object, the sharpness measuring means 50 is configured to measure transmitted light. However, when the measurement object is not light transmissive, so-called reflected light measurement is performed. Needless to say, this is a configuration for use.
[0026]
In the measurement here, the sharpness of the film F in one or both of the main scanning direction and the sub-scanning direction may be measured.
First, the measurement in the main scanning direction is performed. In this case, it is preferable to temporarily stop the film F at a predetermined position. Further, when measurement in the sub-scanning direction is performed, the measurement can be performed without using a child that stops the film F. Specific operations (movements) in both measurements will be described later. [0027]
FIG. 2 is a schematic side view showing a configuration of a photothermographic printer having a sharpness measuring function according to another embodiment of the present invention.
The printer 60 shown in FIG. 2 is a photothermographic printer that records an image on a light transmissive film-like photosensitive heat-developable recording material (hereinafter referred to as recording material A). 62, an exposure unit 64, a heat development unit 66, a tray 68 for receiving a recorded film, and a sharpness measurement function unit 70. Here, the photosensitive heat-developable recording material is a recording material in which a latent image is recorded by exposure and is colored by heat development to visualize the latent image.
[0028]
Here, the recording material A is normally stored in the magazine 72 as a laminate of 100 sheets or the like and loaded into the printer 60, as in the case of the film shown in the previous embodiment.
The supply unit 62 is a part that supplies the recording material A to the exposure unit 64, and includes a loading unit 74 of the magazine 72, single-wafer means using a suction cup 76 and a supply roller pair 78, and conveyance roller pairs 80 and 82. Configured.
In the supply unit 62, the suction cup 76 sucks one sheet of recording material A, removes it from the magazine 72 and supplies it to the supply roller pair 78, and the supply roller pair 78 supplies the recording material A to the conveyance roller pairs 80 and 82. The conveyance roller pairs 80 and 82 convey the recording material A to the exposure unit 64.
[0029]
The exposure unit 64 is a part that exposes the recording material A imagewise by light beam scanning exposure, and includes an exposure unit 84 that exposes the recording material A and a sub-scanning conveying unit 86.
The exposure unit 84 is a known light beam scanning device. As shown in FIG. 3, the light source 88 of the light beam L, the polygon mirror 90 as an optical deflector, the fθ lens 92, the mirror 94, and a drive control unit. 91 and the like.
In the exposure unit 84, the drive control unit 91 drives the light source 88 with pulse modulation, for example, according to the recorded image. In this way, the light beam L modulated in accordance with the recording image emitted from the light source 88 is deflected in the main scanning direction (the direction perpendicular to the paper surface in FIG. 2) by the polygon mirror 90, and the fθ lens 92. The light is incident and imaged at a predetermined recording position by the mirror 94.
[0030]
On the other hand, the sub-scanning conveying means 86 holds the recording material A at the recording position by a pair of conveying rollers 96 and 98 arranged with the recording position (scanning line) in between, and a direction orthogonal to the main scanning direction. It is conveyed in the direction of arrow y.
Here, as described above, since the light beam L is deflected in the main scanning direction, the recording material A is two-dimensionally scanned and exposed by the light beam modulated in accordance with the recorded image, and the latent image is recorded. (It is formed.
[0031]
Next, the recording material A on which the latent image is recorded by the exposure unit 64 is conveyed by the conveying roller pair 99 and the like, and is conveyed to the heat developing unit 66.
The heat developing unit 66 is a part that heat-develops the recording material A to visualize the latent image, and includes a heating drum 100, an endless belt 102, and a peeling claw 104.
[0032]
The heating drum 100 is a drum having a built-in heating source, the surface of which is heated to a temperature corresponding to the heat development temperature of the recording material A, and rotates around the shaft 100a so as to be recorded together with the endless belt 102. A is nipped and conveyed.
The endless belt 102 is stretched around four rollers 106 a to 106 d and pressed so as to be wound around the heating drum 100.
The peeling claw 104 peels the recording material A from the heating drum 100, and is configured to lightly contact and detach from the heating drum 100.
[0033]
The recording material A carried into the heat developing unit 18 by the conveyance roller pair 99 is carried between the heating drum 100 and the endless belt 102, is thermally developed while being conveyed according to the rotation of the heating drum 100, and is exposed by exposure. The recorded latent image becomes a visible image. When the leading end of the recording material A is conveyed in the vicinity of the peeling claw 104, the peeling claw 104 lightly contacts the heating drum 100 and enters between the heating drum 100 and the recording material A, and the recording material A is heated to the heating drum. Peel from 100.
After the thermal development, the recording material A peeled off from the heating drum 100 by the peeling claw 104 is discharged to the tray 68 by the discharge roller pair 112 (112a, 112b).
[0034]
The sharpness measuring function unit 70 performs sharpness management (checking) using the test pattern for measuring the sharpness recorded on the recording material A in the printer 60. Similarly, a sharpness control unit 114 and a sharpness measuring unit 116 are included.
These are basically the same as the sharpness measurement function unit 24 of the printer 10 described above, and the sharpness control unit 114 measures the sharpness generated on the recording material A by the pattern generation means described above. The test pattern is recorded and measured, and various processes are controlled in accordance with the measurement results. When performing these operations, an instruction is given to the exposure unit 64 (exposure unit 84) as necessary. This is a part for recording the test pattern and receiving a measurement result of the recorded test pattern and performing a process corresponding thereto.
[0035]
Hereinafter, the QC relating to the sharpness in the printers 10 and 60, that is, the operation of the sharpness measuring function unit 24 and 70 will be described.
Since both have basically the same function, in the following description, the printer 10 will be described as a representative example, and only the differences will be described for the printer 60.
[0036]
When the printer 10 issues a QC execution instruction regarding sharpness, the film F is supplied to the recording unit 20 as in normal image recording, and the drive control unit 46 under the instruction from the sharpness measurement function unit 24. However, the thermal head 18 is driven in accordance with the test pattern for measuring the sharpness, the test pattern is recorded on the film F, and conveyed toward the tray 22.
[0037]
On the other hand, also in the printer 60, the recording material A is supplied to the exposure unit 64 in the same manner as in normal image recording, and the drive control unit 91 performs the test under the instruction from the sharpness control unit 114 of the sharpness measurement function unit 70. The light source 88 is modulated and driven in accordance with the pattern, and a latent image of the test pattern is recorded on the recording material A, thermally developed by the heat developing unit 66, and conveyed toward the tray 68 by the discharge roller pair 112a and 112b.
[0038]
The test pattern used here is not particularly limited, and various patterns used for sharpness measurement can be used. Here, as a preferable example, a CTF measurement pattern 52a in the main scanning direction and a CTF measurement pattern 52b in the sub-scanning direction as shown in FIG. 4 are recorded as test patterns. It should be noted that a portion other than this pattern is preferably a black solid 54.
[0039]
The sharpness measuring means 50 is disposed in the middle of the path through which the platen roller 38 and the discharge roller pairs 44a and 44b discharge the film F on which the test pattern is recorded onto the tray 22. Here, first, the case where the sharpness measurement means 50 performs the sharpness measurement in the sub-scanning direction will be described.
In this case, the sharpness measuring means 50 performs the measurement while passing a portion where the test pattern is recorded on the film F through a predetermined position between the discharge roller pair 44a and 44b.
[0040]
That is, as shown in FIG. 5, the film F on which the test pattern (TP) is recorded passes between the illumination light source 50a of the sharpness measuring means 50 and the optical sensor 50b, and the illumination light source 50a (here, As a preferred example, a laser diode (LD) is used) and an optical sensor 50b (same as a phototransistor), and the measurement is performed in a state where the light intensity is adjusted by adjusting the light emission intensity of the LD.
[0041]
As an example, the result of reading the CTF measurement pattern 52b (see FIG. 6A) in the sub-scanning direction as a measurement target by the optical sensor 50b (phototransistor) is as shown in FIG. 6B, for example. Suppose that
The sharpness control unit 48 calculates a CTF curve as shown in FIG. 6C from the density waveform of FIG. 6B and the density of the high density solid part 54 and the low density solid part 56, Is output to an output unit (not shown). The output unit may be provided in the printer main body, or may be provided in a place away from the printer (a place close to the operator).
[0042]
According to the above embodiment, the sharpness measurement test pattern is automatically recorded on the film F, the recorded test pattern is automatically measured, and the result is output to notify the operator. Therefore, when the performance of the printer changes and the quality of the output print (image on the film F) decreases, it is detected immediately, and sharpness degradation that is a problem particularly in medical images is deteriorated. It will be discovered early.
[0043]
In the description of the operation of the above embodiment, the printer 10 shown in FIG. 1 is taken as an example. However, the operation of the printer 60 shown in FIG. 2 is exactly the same, and the same effect can be obtained.
[0044]
In the above-described example, the case where the printer according to the present embodiment performs the measurement of the sharpness in the sub-scanning direction (and the QC based on the result) has been described. However, the present invention is not limited to this. Of course, it is possible to measure the sharpness in the main scanning direction.
[0045]
When measuring the sharpness in the main scanning direction, the sub-scanning CTF measurement pattern 52b shown in FIG. 4 is recorded as a test pattern and measured.
Here, in a normal printer, the film F is not conveyed in the main scanning direction. Therefore, when measuring the sharpness in the main scanning direction, the film F is temporarily stopped and the measuring means is moved in the main scanning direction. Move to, and measure.
[0046]
In this case, the measuring means may be a dedicated means for measuring in the main scanning direction, or may be used also as a means for measuring in the sub-scanning direction. Further, when the printer 10 has a density measurement unit for shading correction, this may be used as a measurement unit for measurement in the main scanning direction.
Further, in the measuring means for measuring the sharpness in the main scanning direction, it is preferable that the beam spot shape of the measuring light is a flat shape that is long in the sub-scanning direction in order to eliminate the adverse effects due to noise.
[0047]
The above measurement operation can be handled in the same manner in the case of the printer 60.
Further, as is clear from the above description, it is sufficient to record only the test pattern that is actually the measurement target on the film F (or the recording material A). In other words, when only the sharpness measurement in the main scanning direction is performed, only the test pattern for that purpose may be recorded, and when only the sharpness measurement in the sub-scanning direction is performed, only the test pattern for that purpose may be recorded. Good.
[0048]
Each of the above-described embodiments shows an example of the present invention, and the present invention should not be limited to these, and appropriate modifications or improvements are made without departing from the scope of the present invention. Needless to say, it may be.
[0049]
For example, the pattern generation means for generating the sharpness measurement test pattern may be a pattern that can be captured once, such as a display device, or a pattern that is captured by multiple captures. In the latter case, intermittent conveyance of the film F (or recording material A) is required.
[0050]
The sharpness measurement results obtained as described above are preferably accumulated in time series and used for monitoring changes in printer performance. For this, for example, it is preferable to use the CTF value at the Nyquist frequency in the main / sub-scanning direction. For this purpose, it is necessary to mount a necessary amount of memory functions in the sharpness control unit 48 described above.
[0051]
FIG. 7 exemplifies a part of a table showing the change with time of the CTF value at the Nyquist frequency in the main / sub-scanning direction. By outputting such a table (or graphed data: see FIG. 8) to the display monitor via the printer user interface, the quality of the output image of the printer can be easily grasped. Is possible.
[0052]
In each of the printers described in the above embodiments, the configuration example in which the sharpness measurement function unit is built in the printer main body has been shown, but the present invention is not limited to this. For example, the sharpness measuring means 50 configured as described above can be externally connected to the printer main body online and the measurement result can be supplied to the sharpness control unit 48.
[0053]
Further, in the above embodiment, the present invention is applied to the thermal recording apparatus using the thermal head and the photothermography. However, the present invention is not limited to these, and can be applied to other various printers. It is. Among them, the present invention is preferably used for a printer for medical use in which sharpness is regarded as important in order to make an appropriate diagnosis.
[0054]
Furthermore, the above-described sharpness measurement results are sent to an appropriate database (DB) installed at a location different from the installation location of the printer via the network, and accumulated, and the monitoring (QC) center, work It is also preferable to prepare for access from other devices connected to the network, such as stations (see FIG. 9).
[0055]
【The invention's effect】
As described above in detail, according to the present invention, a printer that has a sharpness measurement function and can easily perform quantitative management (QC) regarding sharpness at an installation site is realized. There is a remarkable effect of being able to.
[Brief description of the drawings]
FIG. 1 is a schematic side view showing a configuration of a thermal recording type printer having a sharpness measuring function according to an embodiment of the present invention.
FIG. 2 is a schematic side view showing a configuration of a photothermographic printer having a sharpness measuring function according to another embodiment of the present invention.
3 is a conceptual diagram of an exposure unit of the printer shown in FIG.
FIG. 4 is a diagram showing various patterns used for sharpness measurement.
FIG. 5 is a conceptual diagram of a sharpness measurement unit according to an embodiment.
6A is a diagram illustrating a test pattern for CTF measurement, FIG. 6B is a diagram illustrating data obtained by reading the test pattern, and FIG. 6C is a diagram illustrating a Fourier transform result of FIG.
FIG. 7 is a table summarizing changes over time of CTF values at Nyquist frequencies in the main / sub-scanning direction.
8 is a graph of the contents shown in FIG.
FIG. 9 is a schematic configuration diagram of a system including a printer according to the embodiment.
[Explanation of symbols]
10, 60 Printer 12, 74 Loading unit 16, 62 Supply unit 18 Thermal head 20 Recording unit 22, 68 Tray 24, 70 Sharpness measuring function unit 32, 80, 82, 96, 98, 99 Conveying roller pair 34 Conveying guide 36 Cleaning roller pair 38 Platen rollers 44a, 44b, 112a, 112b Discharge roller pair 48, 114 Sharpness control units 50, 116 Sharpness measuring units 52a, 52b Sharpness measuring test pattern 64 Exposure unit 66 Thermal development unit 84 Exposure unit 86 Sub-scanning conveying means 100 Heating drum 102 Endless belt 104 Peeling claw

Claims (5)

A printer configured to be able to record a two-dimensional image on a recording material by a recording means,
Pattern generating means for generating at least a test pattern for sharpness measurement;
Concentration measuring means comprising an illumination light source and an optical sensor for illuminating the recorded image to be output, and an output means for measuring results by this measuring means,
A test pattern for measuring the sharpness generated by the pattern generating means is recorded on the recording material, and the sharpness is measured by moving the recording material and the concentration measuring means relatively one-dimensionally. The printer outputs the measurement result to the output means. The density measuring means measures a sharpness measurement test pattern recorded on the recording material in at least one of a main scanning direction or a sub-scanning direction orthogonal to the recording means. The printer according to claim 1. The printer according to claim 1, wherein the density measuring unit includes both a transmissive recording material and a reflective recording material that can be selectively used. The printer according to claim 1, further comprising a measurement result management function in addition to each of the units. The printer according to claim 1, wherein a CTF measurement pattern is used as the sharpness measurement test pattern.

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