JP2002079663A - Apparatus and method for inspecting recording element of printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To specify malfunctioning nozzles accurately by a simple constitution. SOLUTION: Odd number nozzles for a black ink are driven to record a check line 45a for the odd number nozzles. Then, after a recording paper 17 is sent, even number nozzles for the black ink are driven to record a check line 45b for even number nozzles. In the same manner, check lines 45c-45h for yellow, magenta and cyan colors are recorded. A line sensor 46 having light-receiving elements 46a arranged to positions corresponding to the lines 45a-45h is set. The line sensor 46 is moved parallel to a horizontal scanning direction M by a scanning mechanism 67. A density of recording pixels P of each of lines 45a-45h is read by each light-receiving element 46a synchronously with the parallel movement. The nozzle which records a pixel P2 having the density not reaching a predetermined value is specified as the malfunctioning nozzle. Since a gap is formed between the recording pixels P, the malfunctioning nozzle can be specified surely.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for inspecting recording elements of a printer, and more particularly to an apparatus and method for inspecting recording elements which can easily inspect the state of each recording element.

[0002]

2. Description of the Related Art Printers that record images on recording paper include printers using an ink jet head and printers using a thermal head. In these printers, the printing element may malfunction for some reason. For example, in an ink jet printer, ink clogging occurs at a nozzle that discharges ink, and the ink discharge amount is reduced or ink is not discharged.
In this case, streaky color unevenness and density unevenness occur in the recorded image.

[0003]

Conventionally, when a recorded image is observed, if streak-like color unevenness or density unevenness occurs, the mode is switched to a head cleaning mode to perform cleaning and ink clogging. And abnormalities in the ejection direction are eliminated. In the cleaning process, the ink is vigorously ejected from each nozzle, the nozzle is sucked from outside to suck out the ink, and the periphery of the nozzle is wiped. As described above, in the case of manual observation, the detection of ink clogging is delayed, and an image may be recorded in a state where print quality is deteriorated. In a home-use printer that enjoys printing personally, such a decrease in recording quality does not have much effect, but when used for business use, the delay in finding malfunctions of the recording element causes a large number of defective prints. Therefore, it is desired to reliably and easily find a malfunction of the printing element.

In recent years, the density of nozzles of an ink jet head has been increased, and high-quality images can be recorded. Accordingly, it has become difficult to easily identify a defective nozzle.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to provide a printing element inspection apparatus and method which can reliably and easily find a malfunction of a printing element. .

[0006]

According to a first aspect of the present invention, there is provided a printing element inspection apparatus for a printer, comprising:
In the arrangement direction of each recording element, the recording elements are driven at intervals of n (n is a natural number) to record the first recording element check line of n intervals, and then the recording elements to be driven are changed to n. A head state check line recording unit for recording a second recording element check line by driving the recording elements one by one, and sequentially recording each check line up to the (n + 1) th recording element check line in the same manner; For reading the state of the recording element with a sensor and inspecting the state of the recording element.

The number of the recording elements to be driven may be plural in addition to one as in the first aspect of the present invention, and may be plural in the case of the second aspect of the present invention. The pixel is recorded in accordance with, and based on this, a defective element or the like is specified for each of a plurality of recording elements. It is preferable that the sensor includes a light receiving element, and the light receiving element is moved in the arrangement direction of the recording elements to read the density of each recording pixel on each recording element check line. Further, it is preferable that the sensor is configured by arranging the light receiving elements at a recording pitch of each recording element check line in a direction orthogonal to the arrangement direction of the recording elements. Further, the sensor may be configured by arranging the light receiving elements in the arrangement direction of the recording elements so as to correspond to each pixel by a check line.

It is preferable that the recording head is an ink jet head, and that an ink discharge state of a nozzle of the ink jet head is inspected by the head state check line to perform an alarm or a head recovery measure.

According to a seventh aspect of the present invention, in the printer printing element inspection method, the number of printing elements is n in the array direction of each printing element.
(N is a natural number), the first recording element check line is printed every n recording steps, and then the recording elements to be driven are different, and the second recording element is also driven every n recording steps. A check line is recorded, and thereafter, the n + th
Each check line is printed up to the first print element check line, and the density of each print pixel on the first to (n + 1) th check lines is read by a sensor to detect a malfunction of the print element. It should be noted that, in addition to one drive element, a plurality of drive elements may be used. In this case,
A defective element is specified in units of a plurality of recording elements.

[0010]

FIG. 1 is a schematic view showing an ink jet printer according to the present invention. Inkjet printer 9
Is a paper feed unit 10, an image recording unit 11, a recording paper reservoir 1
2, a cutter unit 13 and a sorter 14.
The paper supply unit 10 includes a paper supply roller 16 in a recording paper magazine 15.
Is rotated to pull out the recording paper 17 from the magazine 15. The pulled out recording paper 17 is sent to the image recording unit 11. In the present embodiment, the recording paper 17 has a width of A4 size, and enables the printing of A4 size. However, the width and the recording length of the recording paper 17 may be appropriately changed.

The image recording section 11 includes a pair of first and second conveying rollers 20 and 21, a thermal head 22 for preheating, and an ink jet head 23. The first and second transport roller pairs 20 and 21 are rotationally driven by a motor 19 via a driver 18 to nip and transport the recording paper 17. These first and second transport roller pairs 20, 2
1, a preheating thermal head 22 and an ink jet head 23 are mounted. These heads 2
Reference numerals 2 and 23 are arranged in parallel with the recording paper width direction (main scanning direction) orthogonal to the recording paper 17 feeding direction. Platen rollers 24 and 25 are disposed below the preheating thermal head 22 and the inkjet head 23, and these platen rollers 24 and 25 support the recording paper 17.

The preheating thermal head 22 includes a shift mechanism 2
6 is configured to be movable up and down. When recording is performed by the inkjet head 23, the recording paper 17 is lowered to sandwich the recording paper 17 between the platen roller 24, and the recording paper 17 is preheated by each heating element. The shift mechanism 26 is set at a retracted position apart from the recording paper 17 except during recording. As shown in FIG. 2, the thermal head 22 is provided with a number of heating elements 27 arranged in a line in the main scanning direction M. The preheating is performed to dry the ejected ink on the recording paper 17 in a short time at the time of recording by ink ejection.

Therefore, as shown in FIG. 1, each heating element 27 of the thermal head 22 is driven and controlled via a head driving unit 30. Drive data for each heating element 27 is sent to the head drive unit 30 from a system controller (hereinafter simply referred to as a controller) 31. The drive data is determined based on the ink ejection amount of the inkjet head 23. A relatively large amount of preheating energy is applied to the pixel recording area by the heating element 27 of the thermal head 22 for a pixel having a large ink ejection amount. In addition, a relatively small amount of preheating energy is applied to the pixel recording area by the heating element 27 of the thermal head 22 for a pixel having a small ink ejection amount.

From the viewpoint of cooling after preheating, the distance L between the thermal head 22 and the ink jet head 23 is preferably as small as possible. Then, the preheating start position of the thermal head 22 and the recording start position of the ink jet head 23 are specified according to the distance L, and the ink jet head 23 is adjusted to the preheating start position on the recording paper 17.
Is controlled so as to start recording.

As shown in FIG. 3, the inkjet head 23 has nozzles 35, 36, 37, and 38 for line recording of yellow (Y), magenta (M), cyan (C), and black (K). Are arranged in the main scanning direction M. As is well known, a piezo element is arranged in the ink flow path near each of the nozzles 35 to 38 in the inkjet head 23. By contracting and expanding the ink flow path by the piezo element, ink is ejected and supplied.

For this reason, as shown in FIG. 1, the driving of each piezo element is controlled by an ink jet head driving section 39. The inkjet head driving section 39 supplies a driving signal corresponding to the image data to each piezo element. The controller 31 is connected to the inkjet head driving unit 39. The controller 31 has a frame memory 40
Are connected, and image data from an image reading device or an image output device is written in the frame memory 40.

The controller 31 obtains driving data of the piezo element for each nozzle 35 to 38 of each color based on the image data of each color. This drive data is sent to the inkjet head drive unit 39. Then, the controller 31
Each piezo element is driven via the head drive unit 39 in synchronization with the feeding of the recording paper 17. As a result, ink droplets of a size and quantity corresponding to the image data are ejected toward the recording paper 17, and the ink droplets adhere to the recording paper 17. Therefore, a full-color image is recorded on the recording paper 17 by Y, M, C, and K ink adhesion.

In this embodiment, high-quality printing is realized by using both the dot diameter control method and the dot density control method as the gradation expression method. May be adopted. The nozzles of each color are formed at a constant pitch in the sub-scanning direction S, and the piezo elements of each color are driven by shifting the image data to be printed by that amount. Therefore, eventually, ink droplets based on the same color image data are recorded on the same line.

The memory 31a of the controller 31 stores mark creation data. Based on the mark creation data, the controller 31 records a cut mark 42 and a sort mark 43 at the boundary of each image 41 as shown in FIG. In the present embodiment, the recording paper 17
A rectangular cut mark 42 is recorded on one side edge and a rectangular sort mark 43 is recorded on the other side edge.

The memory 31a of the controller 31 stores data for creating a head state check pattern 45. Based on this creation data, the controller 31 performs
As shown in FIG. 5, a head state check pattern 45 is recorded together with the cut mark 42 on the leading end of the recording paper 17.

FIG. 5 is an enlarged plan view showing the head state check pattern 45. The head state check pattern 45 includes a plurality of check lines 45a to 45 for each color.
5h. Check line 45a-45h
Are arranged in the main scanning direction M at a predetermined pitch so that the pixels P due to ink ejection from each nozzle can be detected for each nozzle. The check lines 45a to 45h are arranged in the sub-scanning direction S by the pitch. In the present embodiment, the pitch is set to two nozzles, and recording pixels P are recorded one by one. Therefore, two check lines 45a to 45h are provided for each color. Although each pixel P is recorded at the maximum density in this embodiment, it may be formed with a constant density value such as an intermediate density or another density. Also,
The recording form of the check lines 45a to 45h may be any number of nozzles (n is a natural number) such as every two nozzles and every three nozzles (see FIGS. 6 to 9) in addition to each nozzle. ,
In this case, n + 1 check lines are recorded.

As described above, since a gap is formed between the pixels P corresponding to the nozzles to be inspected, it is possible to easily grasp the correspondence between the pixels P and the nozzles 35 to 38 on which the pixels P are recorded. Also, head state check pattern 4
Even when the array density of the light receiving elements 46a is not as high as the density of the recording pixels P when reading 5 with the line sensor 46 described later, the recording is performed so as to provide a gap in each pixel P in this manner. 38 and the pixels P thereby can be easily and surely associated with each other by the line sensor 46.

As shown in FIG. 1, a controller 31 has a pulse generator 51 for detecting a feed amount of the recording paper 17.
Is provided. The pulse generator 51 is a recording paper 1
7 generates a pulse number proportional to the feed amount of the recording paper 17. The controller 31 includes the pulse generator 5
The number of pulses from 1 is counted to determine the recording paper feed amount per unit time. Based on this feed amount, the controller 3
1 is a thermal head 22 or an inkjet head 23
Is determined. Further, the driving data of each heating element 27 is corrected according to the feeding speed of the recording paper 17. For example, as the recording paper 17 is fed faster, the amount of heating by each heating element 27 is increased. When the feeding of the recording paper 17 becomes slow, the amount of heating by each heating element 27 is reduced. Further, when the feed speed of the recording paper 17 is close to "0", the heating amount is set to "0" so that the recording paper 17 is not unnecessarily heated. Instead of using the pulse generator 51, the feed motor 19 may be simply constituted by a pulse motor, and the various timings may be determined by counting the number of drive pulses of the motor.

The recording paper reservoir 12 includes a conveying roller pair 21 of the image recording unit 11, a movable guide 55, and a cutter unit 13.
Between the pair of transport rollers 21 and 56 by providing a speed difference (including stopping one of the rollers 56a) between the drive roller 21a and the drive roller 56a. Then, the recording paper 17 is suspended and temporarily stored.

The movable guide 55 includes a pair of conveying rollers 21 and 5.
6, and is rotatably attached to the rotation shaft of the drive roller 21a. The movable guide 55 is used for the recording paper 17.
The leading end of the movable guide 55 is guided to the transport roller pair 5 when the leading end of the recording paper 17 passes.
6 is a guide position (indicated by a two-dot chain line) close to the entrance side of the nip portion, and after the leading end of the recording paper 17 has passed, a retract position (indicated by a solid line) where the recording paper 17 is temporarily stored in a loop. ). When the recording paper 17 hangs down in the space where the movable guide 55 is retracted, the recording paper 17
Is temporarily stored.

The cutter unit 13 includes first, second, and third pairs of transport rollers 56, 57, 58, a check line reading unit 60, and a cutter 61. Each of the transport roller pairs 56 to 58 is driven to rotate by a motor 62. The rotation of the motor 62 is controlled by the controller 31 via the driver 63. The cutter 61 is controlled by the controller 31 via the driver 64, and cuts the recording sheet 17 including the cut mark 42 and the sort mark 43 at the boundary position of each image, and cuts the print 70 for each image.

The check line reading section 60 includes a mark sensor 65, a line sensor 46, and a scanning mechanism 67, as shown in FIG. Mark sensor 65
Is provided with a light receiving element 65a for detecting the cut mark 42 and the sort mark 43, and sends a mark detection signal to the controller 31. In the present embodiment, the cut mark 42
The identification of the sort mark 43 is performed based on the recording position. If it is formed on one of the side edges, it is determined as a cut mark, and if it is formed on the other side, it is determined as a sort mark.

The controller 31 controls the cut mark 42
Further, by controlling the rotation of the motor 62 based on the detection signal of the sort mark 43, each image boundary portion of the recording paper 17 is sent to the cutter 61 in order, and as shown in FIG. To cut twice. As a result, the cut mark 42 and the sort mark 43 at the boundary are cut off, and a print 70 for each image 43 is obtained. The prints 70 are collected on the tray 75 after cutting. Further, based on the detection signal of the sort mark 43, the controller 31 controls the sorter 14 to set a new tray 75 at the print drop position. Thus, each print 70 is inserted into one tray 75 for each order and is bundled for each order.

The sorter 14 is configured by arranging a number of trays 75 on a belt conveyor 76. Then, based on the detection signal of the sort mark 43, the belt conveyor 76 is driven to rotate by the mounting pitch of each tray 75, so that a new tray 75 is set at the print drop position.

At the time of setup immediately after power-on, the controller 31 checks the check line 4 recorded on the leading end of the recording paper 17 by the check line reading unit 60.
Read 5a-45h. First, the recording paper 17 is stopped so that each of the check lines 45a to 45h is positioned at the scanning position of the line sensor 46 based on the detection signal of the cut mark 41. The line sensor 46 includes a light receiving element 46
a are arranged in the sub-scanning direction S, and the pitch is the same as the recording pitch of each of the check lines 45a to 45h. The scanning mechanism 67 translates the line sensor 46 in the main scanning direction M.

The controller 31 synchronizes with the movement of the line sensor 46 in the main scanning direction M by the scanning mechanism 67,
The read signal from the line sensor 46 is received. The controller 31 measures the density of each pixel P based on the read signal, and when the density does not exceed a predetermined reference value,
The nozzle on which the pixel P is recorded is specified as a malfunction nozzle. For example, in FIG. 5, since the density of the second pixel P2 on the yellow odd-numbered check line 45a is low, the third nozzle that records this pixel P2 is determined to be a malfunctioning nozzle.

When a malfunction nozzle is detected, a cleaning process is performed on the nozzle. In this cleaning process, the recording paper 17 is returned, and the ink is ejected from the malfunctioning nozzle with a larger ejection amount than usual and more vigorously than usual to the recording area adjacent to the head state check lines 45a to 45h. The nozzle is cleaned. Thereafter, similarly, the head state check line 45a including the malfunctioning nozzle is recorded, and by reading the head state check line 45a in the same manner, it is determined whether the clogging of the malfunctioning nozzle has been resolved. . In this embodiment, the recording paper 17 is returned by a predetermined amount, and ink is discharged to a recording area adjacent to the head state check lines 45a to 45h to perform cleaning, thereby suppressing useless use of the recording paper 17. The returning process of the recording paper 17 may be omitted.

If an erroneous nozzle is detected and an erroneous operation is detected even after cleaning of the nozzle, an alarm is issued and an operator is notified of ink clogging. In response to the alarm, the operator selects a separate cleaning mode and cleans the nozzle. In this cleaning mode,
For example, the ink inside the nozzles is heated by a heating element (not shown), and the ink is ejected vigorously to perform efficient cleaning. Instead of or in combination with such cleaning by ink ejection, cleaning by ink suction or wiping of ink adhered to nozzles may be performed. The ink suction is performed by the head recovery processing unit 77. In the head recovery processing unit 77, the inkjet head 24 is displaced to the recovery processing position, a suction head is applied from outside the nozzle, and the nozzle is cleaned by sucking out ink by suction.
In the wiping process of the attached ink, cleaning is performed by wiping the ink attached to the nozzles. If ink clogging is not eliminated by such various cleaning processes, replacement of the inkjet head or the like is performed.

Next, the operation of the present embodiment will be described. When the power is turned on and the printer enters the setup mode, the recording paper 1
First, head state check lines 45a to 45 as shown in FIG.
h is recorded. This head state check line 45a
In the printing of .about.45h, first, the odd-numbered nozzles among the nozzles are driven, and the first check line 45a for checking the state of the odd-numbered nozzles is printed. Next, after the recording paper 17 is fed by a predetermined amount, a second check line 45b for checking the state of the even-numbered nozzles is recorded. These check lines are recorded for each color of K, Y, M, and C.

The head state check pattern 45 including the check lines 45a to 45h of each color is sent to the cutter unit 13, where the check line reading unit 60
The density of each pixel P on each of the check lines 45a to 45h is read. When the density of each pixel does not reach the predetermined density, the controller 31 determines that the nozzle that has printed this pixel is malfunctioning. If there is a malfunctioning nozzle,
The recording paper 17 is returned by a fixed amount, and an unsatisfactory nozzle ejects a larger amount of ink than usual and a more vigorous amount of ink than usual to an unrecorded area adjacent to the head state check pattern 45, so that nozzle cleaning is performed. Done.
Thereafter, the check line including the malfunction nozzle is recorded again, and the malfunction check is performed in the same manner.

If a malfunction is still detected after nozzle cleaning, an alarm is issued to notify the operator of ink clogging. In response to the alarm, the operator selects a separate cleaning mode and cleans the nozzle.

When the head state check processing is completed and there is no malfunction nozzle, printing is started by operating a print start key or the like. In printing, first, the recording area is preheated by the thermal head 22 according to the ink ejection amount. Next, ink is ejected from the inkjet head 23 onto the preheated recording paper 17 to record a full-color image. Since the recording paper 17 of the ejected ink is preheated in advance, the ink is efficiently dried.

As shown in FIG. 4, a cut mark 42 is recorded at the boundary of each image 41. Further, at the break of each order, a sort mark 43 is recorded. Cutter part 1
In 3, based on the detection signal of the cut mark 42 or the sort mark 43, the boundary portion including these marks 42, 43 is cut at the planned cut lines 71, 72.

At the start of recording, a cut mark 42 is recorded at the leading edge of the image 41, so that the margin at the leading end of the recording paper is cut off based on this. When the sort mark 43 is detected, each image is cut off at the sort mark position in the same manner as the cut mark 42, and a sort signal indicating the break of each order is sent.
When the recording of a series of images is completed and the next image is not recorded, after the recorded portion is separated by the cutter unit 13,
The leading end of the recording paper 17 is returned to the second conveying roller pair 21 of the image recording unit 11, and the printing paper 17 enters a print standby state.

In the above embodiment, as shown in FIG. 5, a line sensor 46 in which light receiving elements 46a are arranged in the sub-scanning direction S is provided.
All the check lines 45a to 45h are read, but instead, as shown in FIG. 6, a reading sensor 80 including four light receiving elements 80a is sent in the main scanning direction M by the scanning mechanism 81, and each color is read. Check line 82a ~
82d may be read at one time. In this embodiment, 3
The first to fourth four check lines 82a to 82d in which three pixels P are recorded by driving the nozzles one by one are shown. In this case, after reading the check lines 82a to 82d of one color, the recording paper 17 is fed by a predetermined amount, and the check lines 8a to 82d of the next color are read.
By reading 3a to 83d and repeating the following,
The head status check lines of the four color nozzles are read.

FIG. 7 shows that a sensor 85 having one light receiving element 85a is replaced by a scanning mechanism 86 in the sub-scanning direction S for each of the check lines 82a to 82d and 83a to 83d instead of the sensor having four light receiving elements. An embodiment is shown in which each check line is read one by one. In this case, after the reading, the recording paper 17 is fed by one line, the next check line is read, and thereafter, this is repeated to read the head state check pattern.

Also, instead of moving the sensors 80 and 85 in the main scanning direction M, as shown in FIG.
A line sensor 90 in which light receiving elements 90a are arranged is provided for each check line 8 in synchronization with the feeding of the recording paper 17.
2a to 82d and 83a to 83d may be read. In this case, check lines 82a to 82d,
Since the nozzles 83a to 83d are printed with n nozzles skipped (in the illustrated example, three nozzles skipped), it is possible to easily associate the print pixel P with the nozzle on which the print pixel P is printed, and to easily identify the malfunctioning nozzle. It can be detected with high accuracy. In this case, by setting the array density of the light receiving elements 90a equal to or higher than the array density of the nozzles, a malfunctioning nozzle can be specified with high accuracy.

As shown in FIG. 9, the light receiving element 91a
Check lines 82a-82d, 83a-
When using the line sensor 91 reduced to a pixel density of about 83d, a scanning mechanism 92 for moving the line sensor 91 by one nozzle in the main scanning direction M may be provided. In this case, after reading one check line,
By shifting the line sensor 91 in the main scanning direction M by the pitch of one nozzle before reading the next check line, the density of each recording pixel P can be reliably read in the same manner. Can be specified with high accuracy.

In the above embodiment, the head state check pattern 45 is set in the setup mode when the power is turned on.
Is recorded to monitor the head state, but the monitoring of the head state may be performed at appropriate intervals. For example, the head state check pattern 45 may be recorded at the leading end position or the trailing end position of the leading image of each order, or may be recorded at the leading end position or the trailing end position of each image. Further, the head state check pattern 45 may be recorded every time a fixed number of images are recorded. For example, 10
When the recording paper 17 is replaced after recording the images, or when a predetermined time, for example, 10 minutes, has passed and the leading end of the image passes, the head state check pattern 4 is used.
5 may be recorded. Also, this head state check pattern 45 is recorded in an inspection process in factory assembly,
Detection of a defective head or the like may be performed.

In the above embodiment, the pattern reading section 60 for reading the head state check pattern 45 is incorporated in the printer, but it may be provided separately from the printer. For example, a defective nozzle may be specified using a flatbed scanner or the like as a pattern reading unit.

Before recording the head state check pattern 45, ink may be ejected from each nozzle to perform head cleaning, and thereafter, the head state check pattern 45 may be recorded. The head cleaning is performed by ejecting ink to the recording paper 17 and may be performed with an ink receiving pad facing the ink jet head, though not shown, in addition to performing the ink cleaning on the recording paper 17.

In the above embodiment, a plurality of check lines 45a to 45h are arranged and a head state check pattern 4
5 are formed, but they may be formed separately. For example, when a check line is recorded for each image, a head state check pattern for K is recorded on the first image, a head state check pattern for Y is recorded on the next image, and M The head state check pattern for C may be separated and recorded in the next image, as in the head state check pattern for C.

In the above embodiment, the driving data of each heating element is changed in accordance with the ink ejection amount, and the preheating amount is increased in an area where the ink ejection amount is large so that the ink is dried efficiently. However, the preheating by the thermal head may be performed by simply driving each heating element uniformly.
In addition to the preheating by the thermal head, preheating may be performed by incorporating a heater in the platen roller.

Instead of preheating or in combination with preheating, the ink may be dried by blowing hot air after discharging the ink. In this case, a drying device, for example, a hot air head is provided, and hot air is blown onto the recording paper after ink ejection. The ink may be naturally dried without using a preheating device or a drying device.

In the above embodiment, as shown in FIG.
In each of the inkjet heads 23, the Y, M, C, and K nozzles 35 to 38 are formed in a line shape. However, the invention is not limited to this, and a plurality of inkjet heads in which nozzles of each color are divided and arranged are used. The present invention may be carried out for those that have been. For example, as shown in FIG. 10, a K inkjet head 110 having a nozzle for black ink,
Two print stages 112, 1 using ink jet heads 111 having respective nozzles of Y, M, and C for each color.
13, the print stages 112, 11
The thermal heads 114 and 11 are respectively provided on the recording surface side at the upstream side in the recording paper feeding direction.
5 is provided. Reference numeral 116 denotes a leading edge sensor that detects the leading edge of the recording paper 17, and 117 denotes a mark sensor that detects a cut mark.
The recording start position is specified based on the 17 output signals.

Each of the print stages 112, 113
During this time, the recording paper 17 between the print stage 113 and the cutter unit 13 is provided with a slack 17a, and a slight feed fluctuation of the recording paper 17 in each of the print stages 112 and 113 is transmitted to another print stage. I try not to be. Then, the amount of ink ejected to the unit heating area on the recording paper by one heating element is obtained from the image data, and the amount of heating is controlled according to the amount of ink ejected to the unit heating area. Thus, when the ejection amount is large, the heating amount is increased, and the ink is dried efficiently and in a short time.

Also in this embodiment, each head 11
Using 0,111, the head state check pattern 45
(See FIG. 5) at the leading or trailing edge of the image. By reading the head state check pattern 45 by the check line reading unit 60, a malfunction nozzle is specified. In FIGS. 10 and 11, the same components as those of the embodiment shown in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted. Further, instead of the thermal heads 114 and 115, a warm air head 130 as shown in FIG. 11 may be used.
A warm air head is disposed downstream of 0, 111 in the recording paper feed direction.

As shown in FIG. 11, the inkjet head for K 120, the inkjet head 121 for Y,
The print stages 125 to 12 are provided with an inkjet head 122 for C and an inkjet head 123 for C.
8, each of these print stages 125 to 128
The warm air heads 130, 131, 132, and 133 are provided downstream of the respective heads 120 to 123 in the recording paper feed direction. Then, using each of the heads 120 to 123, the head state check pattern 45 is recorded at the leading end or the trailing end of the image, and is read by the check line reading unit 60, thereby specifying the malfunction nozzle. Also in this embodiment, by arranging the thermal head at the position as shown in FIG. 10, the recording paper is preheated by the thermal head instead of the warm air heads 130 to 133, and the ejected ink is dried. Is also good.

As shown in FIG. 3, the nozzles 35 to 3 for each color
8 may be formed in a plurality of lines in addition to being formed in one line. In this case, the nozzle density in the main scanning direction is reduced by an amount corresponding to the increase in the number of lines, thereby facilitating the manufacture. Further, instead of the nozzle having a length corresponding to the entire width of the recording paper 17, a plurality of inkjet heads having a short length in the width direction of the recording paper are used, and these are combined to form an ink jet head having a long width in the width direction of the recording paper. A head may be configured. In the case of such an ink jet head as well, by providing n + 1 check lines in which pixels are recorded at intervals of n pixels in the main scanning direction, malfunction nozzles can be specified with high accuracy.

In the above embodiment, the pixels P are associated with the nozzles on which the pixels P are recorded in a one-to-one relationship. However, the relationship is not limited to one-to-one, and as shown in FIG. The density of the pixels 100 recorded by the nozzles is detected, and if the detected density does not reach the predetermined value, cleaning may be performed on all of the plurality of nozzles at once. FIG.
In this example, one pixel 100 is recorded on the recording paper 101 by skipping two nozzles and two nozzles as a unit, whereby each check line 102a, 102b, 103
a and 103b. In this case, using a sensor 104 having a detection area 104a corresponding to the pixel,
The malfunctioning nozzles are specified for each group of two. Each of the check lines 102a, 102b, 103a,
The configuration of 103b is not limited to the illustrated one, and various modes are possible. For example, m successive nozzles in the arrangement direction of the nozzles are driven at intervals of n (m, n is a natural number of 2 or more, and n ≧ m), and the first print element check line of n intervals is set. Then, the second check line is recorded by driving the nozzles at different intervals and driving the m nozzles in succession and recording the second check line. Thereafter, similarly, each check is performed up to the (n + 1) th check line. Record the line.

In the above-described embodiment, the present invention is applied to the line printer that records one line at a time in the width direction of the recording papers 17 and 101. In addition, as shown in FIG. The present invention may be applied to a serial printer 163 that scans and records the recording paper 162 in the width direction by using the printer. Note that reference numeral 1
Reference numeral 64 denotes a guide rod for guiding the head carriage 161 in the width direction of the recording paper 162, and reference numeral 165 denotes a recording rod 162.
3 shows a platen member that supports the platen.

When recording the head state check pattern in the serial printer 163, each nozzle is driven sequentially while moving the head carriage 161 in the main scanning direction, and each pixel is obliquely printed with respect to the recording paper 162. Record.

FIG. 14 shows an example of a head state check pattern in the serial printer 163.
The (A) head state check pattern 170 indicates that the recording paper 162 is fed one pixel at a time in the sub-scanning direction S and that the inkjet head 1 is moved by the head carriage 161.
The nozzle 60 is obtained by moving the nozzle 60 in the main scanning direction M and sequentially driving the nozzles in conjunction with this movement. The head state check pattern 170 includes pixels P that are separated in the width direction of the recording paper 162.

The head state check pattern 171 shown in FIG. 14B is obtained by moving the ink jet head 160 in the main scanning direction M by the head carriage 161 without sending the recording paper 162, and interlocking this movement with each nozzle. It is obtained by driving sequentially. The head state check pattern 171 is composed of pixels P which are arranged in a direction obliquely intersecting the width direction of the recording paper 162 and are scattered.

FIG. 14C shows an example of a head state check pattern 172 employed when the number of nozzles is large. In this embodiment, each nozzle is set in the sub-scanning direction S
, And the nozzles of each group are sequentially driven to form a head state check pattern including a plurality of oblique lines.

In the above-described serial printer, the cut mark and the sort mark may be formed by changing the number of times of the head state check pattern and the cleaning pattern, the recording position, the recording order of each color, and the like.

In the above embodiment, ink clogging in each nozzle of the ink jet head and malfunctions of the drive elements and drive circuits of the nozzles are detected. A defect may be detected. For example, when checking for a malfunction of the printing element of the thermal head, the malfunction is corrected by correcting the heating drive data of the malfunctioning printing element. The present invention is not limited to a thermal printer, and the present invention may be applied to a printer that exposes an instant film with a light emitting element head in which a large number of light emitting elements are arranged.

In the above embodiment, the ink jet heads 23, 110, 111, 120-1 having the piezo elements are used.
Although 23 is used, various mechanisms for ejecting ink may be applied. For example, a flow control valve system comprising a piezo element and a diaphragm, a thermal ink jet system in which a heating element is used to heat ink liquid to generate bubbles and eject ink, and an ink droplet is formed by using an electrode. A continuous ink jet system that applies electric charge, collects unnecessary droplets with a deflection electrode on a baffle plate, and discharges necessary ink droplets on recording paper, applies a high voltage according to image signals, and uses this high voltage Various ink jet systems such as an electrostatic suction ink jet system in which ink droplets are sucked onto recording paper and an ultrasonic ink jet system in which ink droplets are generated by vibrating an ink liquid using ultrasonic waves may be used.
Further, the ink used may be other color inks such as light magenta and light cyan in addition to Y, M, C and K.

Although the roll type recording paper is used in the above embodiment, a cut sheet type recording paper may be used instead. In this case, the head state check pattern is recorded outside the image recording area. If necessary, a sort mark may be recorded in addition to the head state check pattern. Parts outside the image recording area including these check patterns and sort marks are cut off by a cutter as necessary.

In the above embodiment, the head state check lines 45a to 45h, 82a to 82d, 83a to 83d
Pixel P is recorded at a constant density, but a check line with a different recording density may be provided for each density. In this case, the operating state of each recording element at each density can be checked. In a printer that uses light ink to improve the gradation expression in a low-density area, a head state test may be performed on the nozzles for the light ink. In this case, similarly to the above-described embodiment, a head state check line is recorded, and the density of each pixel on the head state check line is detected to identify a defective nozzle. Since the density of this light ink is lower than that of normal ink, the defective nozzle is specified by changing the threshold value, increasing the gain, or changing the ink ejection amount.

[0066]

According to the present invention, the recording elements are driven at intervals of n (n is a natural number) in the arrangement direction of each recording element, and the first recording element check line of n steps is recorded. A recording element different from the recording element driven by the first recording element check line, and the recording elements are driven at intervals of n to record the second recording element check line. By recording each check line up to the recording element check line and reading each recording pixel of the first to (n + 1) th check lines with a sensor, the operation failure of the recording element is detected. Can be detected. In particular, in the case of a recording element for image recording in which the recording elements are arranged at a high density, it is necessary to use a sensor having a high-density mounting light-receiving element corresponding to this recording element. By using the recorded check line, it is possible to accurately identify a malfunctioning recording element using a low-cost sensor having a low mounting density of light receiving elements.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an ink jet printer of the present invention.

FIG. 2 is an enlarged front view showing a preheating thermal head.

FIG. 3 is an enlarged front view showing the ink jet head.

FIG. 4 is a plan view showing a cut mark, a sort mark, and a head state check pattern.

FIG. 5 is a schematic diagram showing a head state check pattern and a check line reading unit.

FIG. 6 is a schematic diagram illustrating a check line reading unit according to another embodiment.

FIG. 7 is a schematic diagram illustrating a check line reading unit according to another embodiment.

FIG. 8 is a schematic diagram illustrating a check line reading unit according to another embodiment.

FIG. 9 is a schematic diagram illustrating a check line reading unit according to another embodiment.

FIG. 10 is a schematic view showing another embodiment using two sets of an ink jet head and a thermal head.

FIG. 11 is a schematic view showing another embodiment using four sets of ink jet heads and hot air heads.

FIG. 12 is a schematic diagram showing another embodiment in which a plurality of adjacent nozzles are driven to identify malfunctioning nozzles in a group unit.

FIG. 13 is a schematic diagram illustrating a main part of the serial printer.

FIG. 14 is a plan view showing an example of a head state check pattern in a serial printer.

[Explanation of symbols]

Reference Signs List 9 inkjet printer 10 paper feed unit 11 image recording unit 12 sorter 13 cutter unit 17, 101 recording paper 20, 21 transport roller pair 22, 114, 115 thermal head 23, 110, 111, 120 to 123, 160 inkjet head 41 image 45 , 170-172, head state check patterns 45a-45h, 82a-82d, 83a-83d, 1
02a, 102b, 103a, 103b Check line 46 Line sensor 60 Check line reading unit 61 Cutter 67, 81, 86, 92 Scanning mechanism 70 Print

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kiyotaka Kaneko 798- Address Miyagidai, Kaisei-cho, Ashigara-gun, Kanagawa Prefecture (72) Inventor Yasuyuki Hosono 798- Address Miyagidai, Kaisei-cho, Ashigara-gun, Kanagawa Fuji Photo Film Incorporated F term (reference) 2C056 EA08 EB27 EB40 HA58 2C057 AF72 AL36 AL37 AP83

Claims (8)

[Claims] 1. A printer that prints an image on a recording sheet by relatively moving a recording sheet or a recording head using a recording head having a plurality of recording elements arranged in a line, wherein recording is performed in an arrangement direction of the recording elements. The first printing element check line of n steps is printed by driving the elements by n (n is a natural number), and the second printing element is driven by the same n steps by changing the printing elements to be driven. And a head state check line recording unit for recording each check line up to the (n + 1) th print element check line in order in the same manner, and reading the head state check line with a sensor.
Means for inspecting the state of the recording element. 2. A printer for recording an image on a recording sheet by relatively moving a recording sheet or a recording head using a recording head having a plurality of recording elements arranged, wherein the recording elements are continuously arranged in the arrangement direction of the recording elements. The m recording elements to be driven are driven at intervals of n (m, n is a natural number of 2 or more, and n ≧ m) to record a first recording element check line that is skipped by n, and then the recording to be driven The second print element check line is printed by driving the elements in succession by n and skipping the m print elements in a similar manner, and thereafter, in the same manner, each check line is sequentially printed up to the (n + 1) th print element check line. A head status check line recording unit, and the head status check line is read by a sensor,
Means for inspecting the state of the printing element in units of a plurality of printing elements. 3. The sensor according to claim 1, wherein the sensor includes a light receiving element, and the light receiving element is moved in a direction in which the recording elements are arranged to read the density of each recording pixel on each recording element check line. 3. A recording element inspection device for a printer according to claim 1. 4. The recording apparatus according to claim 3, wherein said light receiving elements are arranged at a recording pitch of each recording element check line in a direction orthogonal to an arrangement direction of said recording elements to constitute said sensor. Device inspection device. 5. The sensor according to claim 1, wherein the sensor includes a light receiving element, and the light receiving element is arranged in an array direction of the recording elements in correspondence with each pixel by the check line. Printer recording element inspection device. 6. The recording head is an inkjet head, and inspects an ink ejection state of a nozzle of the inkjet head by the head state check line,
6. The apparatus according to claim 1, wherein an alarm or a head recovery measure is performed. 7. A printer for recording an image on a recording sheet by relatively moving a recording sheet or a recording head using a recording head in which a plurality of recording elements are arranged, and recording in an arrangement direction of the recording elements. The first printing element check line of n steps is printed by driving the elements by n (n is a natural number), and the second printing element is driven by the same n steps by changing the printing elements to be driven. Then, similarly, each check line is sequentially recorded up to the (n + 1) th print element check line in the same manner, and the density of each print pixel of the first to (n + 1) th check lines is read by a sensor. And detecting a malfunction of the printing element. 8. A printer that prints an image on a recording sheet by relatively moving a recording sheet or a recording head using a recording head in which a plurality of recording elements are arranged, wherein the recording elements are continuously arranged in the arrangement direction of the recording elements. The m recording elements to be driven are driven at intervals of n (m, n is a natural number of 2 or more, and n ≧ m) to record a first recording element check line that is skipped by n, and then the recording to be driven The second print element check line is recorded by driving the m elements in succession by skipping n elements with different elements, and thereafter, similarly, each check line is sequentially recorded up to the (n + 1) th print element check line. A printing element inspection method for a printer, wherein a malfunction of the printing element is detected by reading a density of each printing pixel on the first to (n + 1) th check lines by a sensor.