JP2002127446A - Printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printer wherein a complex operation such a timing of ejection of ink which is controlled by a software controlling is eliminated and the reliability of a software can be enhanced. SOLUTION: When a flag 15b attached to a carriage 15 moves across a photosensor 21, a photosensor 8 for detecting non-ejection is turned on. When the flag 15b passes through the sensor 21, the sensor is released from the light- blocking condition and then the sensor 21 turns off and the ejection of ink for detection non-ejection is started. At that time, the photosensor 8 is warmed and the stable detection is started.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus such as a facsimile provided with means for detecting abnormal ink ejection.

Here, printing includes applying ink to all ink supports to which ink is applied, such as cloth, thread, paper, sheet material, etc., and the printing apparatus includes various information devices or their output devices. The present invention is applicable to these printers.

[0003]

2. Description of the Related Art With reference to FIG. 9, the configuration of a printing apparatus provided as output means in a conventional facsimile apparatus will be schematically described.

[0004] A plurality of print papers P are stored in a cassette 151 in a stacked manner.
It is fed out one by one and sent out to the transport roller 153.
The sheet is further conveyed to the printing section B. This print section B
Is an inkjet system, has a print head that reciprocates in the main scanning direction (perpendicular to the paper surface) and has a large number of ink discharge ports (for example, 128 ink discharge ports) in a row. An image is printed on the upper surface using ink ejected from the head. The printed paper P after image printing is conveyed to a discharge section along a lower guide 155 by a discharge roller pair 154 disposed downstream of the print section B, and is discharged by a discharge roller 156 and a discharge roller 157 to a discharge stacking section. The paper is discharged onto the paper stacker 158 and stacked.

The print head has a built-in ink tank,
Equipped with a cartridge type ink jet print head that can be replaced with a new one for each print head when the ink runs out.To enable color printing while miniaturizing the device main body, cartridges for black printing and color The print cartridge can be installed in any of the print cartridges. The black print cartridge has 128 ink discharge ports for discharging only black ink, and the color print cartridge has 64 ink discharge ports.
It has 24 ink ejection ports and ink tanks for the four colors for each of the three principle ink ejection ports, yellow, cyan, and magenta. The outer shapes of the black print cartridge and the color print cartridge are the same, so that the ink capacity per color of the color print cartridge is less than one-fourth of the ink capacity of the black print cartridge. .

[0006] Here, various printing apparatuses for printing on print media such as paper and OHP sheets have been proposed. Among them, the printing apparatus directly ejects ink from a print head onto print paper. Attention has been paid to a printing apparatus having advantages such as low running cost and quiet printing operation.

In applying the above printing apparatus to a facsimile machine, it is necessary to detect an unprintable state such as out of ink or defective ejection in order to reliably print received image information. As a detection method, a predetermined number of inks are ejected into a gap between the light emitting element and the light receiving element of the transmission type photo sensor, and a change in the sensor output is detected by utilizing the fact that the ink blocks light. It is conceivable to use a technique for detecting an ink ejection abnormality caused by a decrease in the remaining amount or a head abnormality.

The transmission type photosensor can project substantially parallel light toward the light receiving element by integrally forming a lens on the light emitting surface of the light emitting element. On the light receiving surface of the light receiving element, a hole of about 0.7 mm × 0.7 mm is formed on the optical axis by a mold member, and the detection range is about 0.7 mm in the height direction and about 0 in the width direction in the entire region between the light receiving and emitting. Narrow down to 0.7 mm.
The optical axis connecting the light emitting element and the light receiving element is arranged in parallel with the ink ejection orifice row of the print head, and the interval between the light emitting element and the light receiving element is wider than the ink ejection orifice row of the print head. When the positions of the ink ejection port arrays are matched, all the ink droplets ejected from each ink ejection port of the print head can pass through the detection range between the light emitting element and the light receiving element. When the ink droplet passes through this detection range, the ink droplet blocks light from the light emitting element side, reduces the amount of light to the light receiving element side, and can obtain a change in output of the light receiving element.

Here, if the output of the transmission type photosensor changes by a certain amount or more, it is determined that the output is normal.

Conversely, if the output change is equal to or less than a certain amount, the printing operation is performed until the ink ejection is detected as abnormal and a return operation to the ink ejection normal state such as suctioning the ink from the ejection port is performed. , And accepts facsimile reception or stores received data in a memory.

[0011] Such a technique is considered to be an effective means because it is possible to detect abnormal ink ejection without adding a special component to the print head.

It is assumed that the above-described ink ejection abnormality detection is always executed for all the ink ejection ports after completion of printing each page.

The control of software for realizing the detection of non-ejection of ink will be described with reference to FIGS. 10 and 11. FIG.

In the non-ejection detection operation, the carriage is moved so as to pass the non-ejection detection sensor and eject ink toward the detection sensor. The detection sensor detects this ink and checks whether or not the ink has been ejected. For this,
The detection LED is turned on just before the carriage passes through the sensor, and ink is ejected shortly before reaching the sensor. After the carriage passes the sensor, the detection LED
Turn off.

The carriage stops its operation and moves to the next position. The moving distance of the carriage is long enough to discharge to the detection sensor.

Since the shorter the lighting time of the detection sensor LED is, the longer the life of the sensor is, the lighting time is shortened as much as possible.

FIG. 10 is a software flow chart for controlling the on / off state of the LED of the sensor and controlling the ink ejection and the carriage motor for this detection operation.

In step S1, the carriage operation is started, and a timer for a non-discharge detection sensor and a discharge timer for a non-discharge detection are started.

In step S2, it is checked whether the timer for the non-discharge detection sensor has reached the sensor ON (active) time. If Yes, proceed to Step S3.

In step S3, the non-discharge detection sensor is turned on. Restart the timer for the non-discharge detection sensor. This is to turn off the detection sensor.

In step S4, it is checked whether or not the non-discharge detection discharge timer has reached the discharge start time. Ye
If s, the process proceeds to step S5.

In step S5, ink ejection for non-ejection detection is started. The sensor also starts checking for the passage of ink.

In step S6, it is checked whether the timer for the non-ejection detection sensor has reached the sensor off time. Yes
If so, the process proceeds to step S7.

In step S7, the non-discharge detection sensor is turned off to terminate the detection.

FIG. 11 is an explanatory diagram of processing related to print control of the facsimile machine. Here, there are seven process processes P1 to P7.

This is done by determining the priority order and performing P1 according to various cases such as a print operation state and a stop state.
To P7 are different.

Here, the non-discharge detection operation state will be described. The four non-discharge detection controls of P2, the interface control of P3, the carriage motor control of P4, and the ink discharge control of P7 are processed in parallel or in order. You.

[0028]

However, in the above technique, a considerable load is imposed on the processing of the CPU which realizes various processings for the carriage operation and the non-ejection detection. Although recent CPUs can process at high speed at low cost, the lighter the load, the better the performance of the whole apparatus.

Software processing becomes complicated in order to improve reliability and achieve accuracy.

The software timer (1) discharges ink for non-discharge detection toward the sensor with high accuracy.
(2) In order to minimize ink consumption,
(3) In order to shorten the on-time of the sensor LED as much as possible, it is necessary to provide a wait time from when the sensor LED is turned on to when the sensor LED is sufficiently stable for detection.
For example, it takes about 10-100 milliseconds for the LED to stabilize.

[0031]

According to one aspect of the present invention, there is provided a printing apparatus for performing printing using a head for discharging ink on a print medium based on image data. The ejection abnormality detection means for detecting an abnormality is placed near the detection means for detecting the position of the carriage, and the length of the flag for detecting the position of the carriage is set to a predetermined length. In this method, the control unit activates the ink discharge abnormality detecting unit when the unit crosses the unit and starts the ink discharge.

According to the above arrangement, arranging the ink discharge abnormality detecting means near the carriage position detecting means and executing the discharge detecting process can improve the discharge accuracy for the detection and the detection process. This simplifies software processing, reduces the load on detection processing, and improves reliability.

Further, by detecting the ink discharge by the position sensor of the carriage, one carriage sensor can be omitted and the cost can be reduced.

Further, if two carriage sensors are used, the mechanical flag for the sensor can be made smaller than the cost, and the degree of freedom in designing the mechanism can be improved. Further, the moving speed of the carriage can be increased, and the degree of freedom in designing the ink ejection detection sequence is increased.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A configuration of a printing apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a main part of a facsimile machine as an embodiment of the printing apparatus of the present invention, FIG. 2 is an enlarged perspective view of the printing section shown in FIG. 1, and FIG. FIG. 3 is a block diagram illustrating a configuration of the facsimile machine illustrated in FIG. 2.

First, a schematic configuration of the facsimile apparatus will be described with reference to FIG.

In FIG. 1, A is a reading unit for optically reading an original, B is a printing unit which is a printing device, and C is a sheet cassette and sheets such as printing paper loaded thereon are separated and supplied to a printing unit B. It is a paper feed unit.

In the reading unit A, the original S is indicated by an arrow F
Are transported along a document transport path indicated by. That is, the document S is stacked on the document tray 41 of the reading unit A with the image side facing down. The stacked originals S are separated and conveyed one by one from below by a separation piece 45 and a separation roller 46,
The sheet is conveyed by the separation roller 46 to the reading position of the reading sensor 48.

The reading sensor 48 arranges a light source (not shown) and a photoelectric conversion element facing the light source in a line in the main scanning direction of reading, and has a length corresponding to the width of the image surface of the document S. At least a line sensor that converts an image of the document S into an electric signal. Reference numeral 49 denotes a white roller which suppresses the lifting of the document S with respect to the reading sensor 48, and at the same time, conveys and discharges the document S in the conveying direction (sub-scanning direction). The discharged documents S are sequentially stacked on a document discharge tray 51. The separation roller 46 and the white roller 49 are driven to rotate by a reading motor (not shown).

Next, the flow of the printing paper P in the printing unit B and the paper feeding unit C will be described.

The print paper P is transported along a print paper transport path indicated by an arrow G in FIG. That is, the print paper P stacked on the paper feed tray 1 of the paper feed unit C is
The paper is picked up by the paper feed roller 2 and the retard roller 3 and sent to the print unit B by the paper feed roller 2. In the printing unit B, printing is performed on the printing paper P by the printing head 5 as printing means. After the printing paper B is conveyed in the apparatus by a certain distance, the printing paper P is discharged by discharging rollers 6 as discharging means. The sheets are discharged and stacked on a paper stacker.

Next, referring to FIG.
A specific configuration of the printing unit will be described.

In FIG. 2, the print head 5 of the present embodiment has a built-in and integrated ink tank (ink container), and can be replaced with a new one for each print head when ink runs out. Equipped with an inkjet print head. Note that the print head 5 may be of a type that can separate only the ink tank from the head.

The print head 5 used in this embodiment is
It is an ink jet type print head. Both the black print cartridge and the color print cartridge can be replaced as appropriate. The black print cartridge has a resolution of 360 dpi and 128 ink ejection ports are arranged in a line. With the arranged ink ejection port row,
The ink is ejected from the ejection port at the tip of the ink ejection port by the pressure of the film boiling generated in the ink by the heat generated by the electrothermal conversion element provided in the ink ejection port.

On the other hand, the color print cartridge has a row of ink discharge ports arranged in a line like the black print cartridge, and has 64 black ink discharge ports.
Each of the three primary colors of yellow, cyan, and magenta has 24 ink ejection ports. The outer shape of each cartridge is the same. The ink capacity per color of the color print cartridge is one fourth or less of the ink capacity of the black print cartridge.

Reference numeral 15 denotes the direction in which the print paper P is transported (sub-scanning direction, arrow G) while holding the print head 5 with high precision.
Is a carriage for reciprocating in the direction orthogonal to the direction, ie, the main scanning direction (the direction of arrow H), and is slidably held by the guide rod 16 and the abutting portion 15a. The reciprocation of the carriage 15 is performed by a pulley 17 and a timing belt 18 driven by a carriage motor (not shown). At this time, a print signal and electric power supplied to the print head 5 are supplied from the electric circuit of the apparatus main body by the flexible cable 19. The print head 5 and the flexible cable 19 are connected to each other by pressing the contacts to each other. When a specific contact of the print head 5 is opened and the connection is detected, which of the monochrome cartridge and the color cartridge is mounted will be described later. It is possible for the CPU to perform the recognition.

Reference numeral 20 denotes a cap which functions as ink receiving means, and is arranged corresponding to a position (home position) where the carriage 15 waits. The cap 20 is moved up and down as needed, and when it is raised, it comes into close contact with the print head 5 and covers the surface including the ink discharge ports forming a line to prevent evaporation of ink and adhesion of dust.

In this embodiment, the print head 5
A carriage home sensor 21 provided on the apparatus main body and a light shielding plate 15b provided on the carriage 15 are used to position the and the cap 20 so as to be relatively opposed to each other. The carriage home sensor 21
A transmission type photo interrupter is used, and when the carriage 15 moves to the standby position, light emitted from a part of the carriage home sensor 21 emits light to the light shielding plate 15.
It detects that the transmission is blocked by b.

The print paper P is fed upward from the lower side in FIGS. 1 and 2, is bent horizontally by the paper feed roller 2 and the paper guide 22, and is conveyed in the direction of arrow G (sub-scanning direction). You. Feed roller 2 and paper discharge roller 6
Are driven by print motors (not shown), respectively, and convey the print paper P in the sub-scanning direction with high precision in conjunction with the reciprocation of the carriage 15 as necessary. Reference numeral 23 denotes a spur, which is formed of a material having high water repellency, and comes into contact with the surface of the print paper P only at the peripheral portion having a blade shape. The spurs 23 are arranged at a plurality of locations facing the discharge roller 6 and at a predetermined distance in the main scanning direction by a bearing member (not shown). The unfixed image on the print paper P immediately after printing is provided. Print paper P without touching the image
Are guided and transported.

The photo sensor 8 constituting the discharge abnormality detecting means is disposed between the cap 20 and the end of the print paper P at a position facing the ink discharge port array of the print head 5. This photo sensor 8 is a print head 5
Is a transmission type photo interrupter that directly optically detects ink droplets ejected from the ink ejection openings of the print head 5, clogging of the ink ejection openings of the print head 5 and the ink liquid passage communicating therewith, and the remaining amount of ink in the ink supply system. The presence or absence of the ink ejection abnormality of the print head 5 due to the decrease can be determined from the output.

The photo sensor 8 used in the present embodiment uses an infrared LED as a light emitting element, and a lens is integrally formed on the LED light emitting surface so that substantially parallel light can be projected toward the light receiving element. . A phototransistor is used for the light-receiving element, and a hole of 0.7 mm × 0.7 mm is arranged on the optical axis by a molding member on the light-receiving surface of the light-receiving element. 0.7m
m, narrowed down to 0.7 mm in the width direction. Further, an optical axis connecting the light emitting element and the light receiving element is arranged in parallel with the ink ejection port row of the print head 5, the interval between the light emitting element and the light receiving element is wider than the length of the ink ejection port row of the print head 5, When the position of the optical axis is aligned with the position of the ink ejection port array of the print head 5, all ink droplets ejected from each ink ejection port of the print head 5 can pass through the detection range between the light emitting element and the light receiving element. I have. When the ink droplet passes through the detection range, the ink droplet blocks light from the light emitting side, reduces the amount of light to the light receiving side, and obtains a change in the output of the phototransistor as the light receiving element.

Next, the main part of the electric circuit of the facsimile apparatus of this embodiment will be described with reference to the block diagram shown in FIG.

In FIG. 3, reference numeral 24 denotes a control unit for controlling the entire printing apparatus, which is used as a CPU 25 such as a microprocessor, a ROM 26 storing a control program of the CPU 25 and various data, and a work area of the CPU 25. And a RAM 27 for temporarily storing various data. The print head 5 is connected to a control unit via a flexible cable 19,
A control signal from the control unit to the head and a signal line for identifying whether the head is a black print cartridge or a print cartridge are coupled to the print head 5. The output of the photo sensor 8 is digitized by an A / D conversion circuit 28 and can be analyzed by the CPU 25. The carriage motor 30 is a motor whose rotation angle can be controlled by the number of pulse steps by the motor drive circuit. The carriage motor 30 and its motor drive circuit 32 and the motor drive circuit 3 of the print motor 31
3. The reading motor 52, its motor drive circuit 53, and the carriage home sensor 21 are also connected to the control unit 24.
Further, the control unit 24 has a document image reading sensor 48, a printer interface 54 for receiving a print command as a printer from an external computer as a transmitting device that holds image data after transmission, and does not hold image data after transmission. An image data input device such as a line control circuit 55 that receives transmission data from an external facsimile device as a transmission device via a public telephone line and receives reception data is also connected, and performs facsimile transmission / reception, copying, and transmission from an external computer. It is configured so that it functions as a printer. here,
The part for printing the facsimile reception data is an example of the first image data printing means, and the part for printing the image data transmitted from the external computer is the second image data printing means.
And a portion for printing image data read by a document image reading sensor is a document image printing means.

Next, in the present embodiment, C shown in FIG.
The sequence of the ink ejection abnormality detection executed by the PU 25 will be described with reference to the flowchart shown in FIG. 4 and the schematic diagram of the printing unit shown in FIG.

As shown in FIG. 4, when a printing unit operation factor such as copy, facsimile reception, or a print command from an external computer occurs in the standby state (step S1), the printing unit operation factor is copied.
The control unit determines either facsimile reception or a print command from an external computer (step S
2). If it is determined that facsimile reception is performed, it is detected whether the cartridge is for black print or color print (step S3). If it is determined that the cartridge is a black print cartridge, the print paper P is picked up, and one page of image data is printed using the 128 ink ejection ports of the black print cartridge (step S4).
As the carriage 15 reciprocates, the carriage home sensor 21 detects the absolute home position of the carriage 15 (step S5). All the ink ejection ports of the head are located between a position P2, which is about 2 mm beyond the detection position of about 2 mm before the position of the preset ink ejection port array 5a of the print head reaching the detection position of the photosensor 8, and a position P2. 128) at a frequency of 6 kHz (step S6). The number of ink ejections is determined by the moving speed of the carriage and the ejection range. Here, for example, 80
Discharge and discharge. During the continuous ejection, the output of the photo sensor 8 is sampled through the A / D conversion circuit 28 shown in FIG. 3 (step S7). The CPU 25 determines whether or not the sensor output data exceeds a certain value (step S8).

The operation from step S4 to step S8 is a procedure for detecting the presence or absence of ink.
Here, if it does not reach a certain value, it is determined that there is no ink,
Perform error operation. For example, in the case of facsimile, the image data is stored in the memory, an error is displayed, the printing operation is completed, and the image data stored in the memory is printed when the cartridge is replaced (step S9). If the output data is equal to or more than a certain value and the next page exists, the pickup of the next sheet is started and the same operation is repeated. If the next page does not exist, the process returns to the standby state. (Step S10).

If it is determined in step S3 that the cartridge is a color print cartridge, one page of image data is printed using the 64 black ink ejection ports of the color print cartridge (step S11). ), Carriage 15 as in step S5.
Is detected (step S12). Then, using only the 64 ink ejection ports for black ink, the positions P1 and P
Ink is continuously ejected during the interval between Step 2 and Step 2 (Step S1).
3). Next, the sensor output is sampled as in step S7 (step S14). The CPU 25 determines whether or not the sensor output data exceeds a certain value (step S15). Here, if the value does not reach the predetermined value, it is determined that there is no ink, and an error operation is performed (step S9). If the sensor output data is equal to or more than a certain value and the next page exists, the pickup of the next sheet is started, and the same operation is repeated. If not, the process returns to the standby state (step S16).

If it is determined in step S2 that the print mode is a copy mode other than facsimile reception or that the printing unit is caused by a print command from an external computer (printer mode), the above-described series of ink presence / absence detection operations is not performed and one page is printed. Is performed (step S17), and if the next page exists (Yes in step S18)
s) The printing operation is continued, and when the next page does not exist (No in step S18), the process returns to the standby state when the process is completed.

Although the above configuration has been described in connection with an example in which an A / D conversion circuit is used to perform high-speed sampling, a sensor circuit using an inexpensive operational amplifier without using the A / D conversion circuit is used. It is also possible to set a constant threshold value for.

Next, the principle of ejection of the print head used in the printing apparatus of this embodiment will be described.

The print head section applied to the printing apparatus of this embodiment is generally provided with a fine liquid discharge port (orifice), a liquid path, an energy operation section provided in a part of the liquid path, and the operation section. Energy generating means for generating droplet forming energy to act on the liquid.

As an energy generating means for generating such energy, one using an electromechanical transducer such as a piezo element, irradiating an electromagnetic wave such as a laser or the like, absorbing the liquid therein to generate heat, and Ejects droplets by the action of
There is a type in which the liquid is caused to fly, or a type in which the liquid is discharged by heating the liquid with an electrothermal converter. Among them, a print head unit used in an ink jet printing method in which a liquid is discharged by thermal energy has a high density of liquid discharge ports (orifices) for discharging a droplet for printing and forming a flying droplet. Because of this, it is possible to print with high resolution.

A print head using an electrothermal converter as an energy generating means can be easily made compact as a whole as a print head, and has recently been improved in technology and reliability in the field of semiconductors. It can make full use of the advantages of remarkable IC technology and micro-machining technology, and it is easy to make it longer and more planar (binary). It is possible to provide an ink-jet printing head unit which is mass-produced with good productivity and inexpensive in manufacturing cost.

In the ink-jet print head manufactured through the semiconductor manufacturing process using the electrothermal transducer as the energy generating means, liquid paths corresponding to the respective ink discharge ports are generally provided. An electrothermal converter is provided as a means for applying thermal energy to the liquid filling the liquid path and discharging the liquid from the corresponding ink discharge port to form a flying droplet. Has a structure in which liquid is supplied from a common liquid chamber communicating with each liquid path.

As for the method of manufacturing the ink discharge section, the applicant of the present invention provided a solid layer for forming at least a liquid path on the first substrate and an active energy ray curing method for forming at least a wall of the liquid path. After sequentially stacking the active material layer and the second substrate, a mask is stacked on the second substrate, and an active energy ray is irradiated from above the mask, so that at least the liquid in the active energy ray-curable material layer A method has been filed in which at least a liquid path is formed by curing the wall of the path as a constituent part, removing the uncured part of the solid layer and the uncured part of the active energy ray-curable material layer from between the two substrates. 62-2534
No. 57).

From the detection of the home position in step S5 in FIG. 4, the continuous ejection from the ink ejection port in step S6, the sampling of the sensor output in step S7 and the operation flow from step S11 to step S14 are also described.
Supplementary explanation will be given with reference to the flow of FIG.

In FIG. 6, the carriage operation starts in step S1. Next, in step S2, it is checked whether the carriage has moved to the position P1 (whether the home position sensor has been turned on). If the sensor is turned on, the non-discharge detection sensor is turned on in step S3. In step S4, it is checked whether the carriage has moved to the position P2 (whether the home position sensor has been turned off). If it is turned off, ink discharge for non-discharge detection is started in step S5, and at the same time, detection is started by the non-discharge detection sensor. Further, a non-discharge detection sensor timer is started in order to make a timing for turning off the non-discharge detection sensor.

In step S6, it is checked whether the timer has reached the sensor off time. If Yes, the non-discharge detection sensor is turned off in step S7 to end the detection.

Next, FIG. 7A, FIG. 7B and FIG.
The non-ejection operation will be described with reference to FIG.

FIG. 7A is a front view of the carriage immediately before the home position sensor 21 is turned on.
The arrow H direction is the moving direction of the carriage. The front part of the light-shielding plate (hereinafter, referred to as a flag) 15b of the carriage 15 is where the sensor 21 starts to cross.

When the flag 15b crosses the sensor 21, the non-discharge detection sensor in step S3 of FIG. 5 is turned on. Reference numeral 8 denotes a non-discharge detection sensor. Even if the sensor is turned on by a certain software, the light-emitting diode (LED) of the sensor 8 actually warms up and waits for several milliseconds for the detection characteristics of the sensor to stabilize. Time (weight) is required.

FIG. 7B shows a state where the rear portion of the flag 15 b has passed the sensor 21. At this time, the sensor 21 is turned off after the light blocking state is released, and the ink discharge for detecting non-discharge is started in step S5. Arrow F indicates the direction of ink ejection, and reference numeral 15d indicates a mark on the flag for explaining the positional relationship between the row of ink ejection ports and the flag in the direction of arrow H. At this time, the sensor 8 can also start warming detection. The time required for the sensor to stabilize is determined by the length of the flag 15b in the direction of the arrow H and the moving speed of the carriage.

For example, if the length of the flag is 10 mm and the speed of the carriage is 20.0 mm / sec, it takes 50 milliseconds from when the sensor 21 is turned on to when it is turned off. That is, the wait time of the sensor 8 = the length of the flag ÷
The length of the flag or the speed of the carriage can be determined according to the relationship of the speed of the carriage. This is the first point of the present invention.

In this case, software processing is simpler than the method shown in FIG.

The position 15 indicating the ink discharge port array 5a
In terms of the distance between d and the left end of the flag 15b in FIG. 6 and the distance between the sensor 21 and the sensor 8, the ink discharge start position is determined.

If the position 15d of the ink discharge port array 5a has the same positional relationship as the left end of the flag 15b, the ink is discharged from the near side by the distance between the sensor 21 and the sensor 8.

As the position 15d approaches the right end of the flag 15b, the discharge starts at a position closer to the sensor 8. In this manner, the ejection position can be determined by the distance between the flag 15b and the ink ejection port array 5a in the direction of the arrow H (main scanning direction), that is, the position where the flag 15b is attached to the ink ejection port array 5a. Let L be the distance between the two sensors, L1 be the distance between the ejection start position and the ejection detection sensor, and L2 be the distance between the ink ejection port array and the rear end (left end in the figure) of the flag.

[0079]

## EQU1 ## L = L1 + L2. This is the second point of the present invention.

Conventionally, in order to position the ink discharge port array 5a of the print head 5 and the photo sensor 8 so as to be relatively opposed to each other, a home position sensor is used in the same manner as the positioning with the cap 20 described above. The distance from the position of the ink ejection orifice array to the optical axis of the photo sensor 8 when the user is at the home position is set as a constant in a software sequence while taking into account the speed of the carriage in advance. It is necessary to perform a serious operation such that the sensor 8 is accurately aligned with the optical axis of the sensor and the sensor 8 is turned on in advance before detection.

However, according to the present invention, the speed of the carriage,
If the length of the flag, the time until the sensor is stabilized, the distance between the sensor 21 and the sensor 8, and the distance between the ink ejection port array and the flag in the main scanning direction are determined, a troublesome constant is obtained in advance, and the constant is determined in the sequence. There is no need to put it in.

FIG. 7C is a front view illustrating the relationship between the head 5, the sensor 21, and the sensor 8 as the paper feeding direction G. 5a is an ink ejection port array.

(Second Embodiment) Hereinafter, another embodiment of the printing apparatus of the present invention will be described with reference to FIGS. 8 (a) and 8 (b).

FIG. 8A is a front view in which the first carriage home position sensor is turned on, and FIG. 8B is a front view in which the second carriage home position sensor is turned on.

Each of the first position in the first embodiment,
This applies to the second position. Therefore, the same control as the control flow of FIG. 6 in the first embodiment can be applied to the second embodiment.

A feature of this embodiment is that the wait time for the sensor 8 is determined not by the length of the flag but by the distance between the first carriage sensor 21a and the second carriage sensor 21b. That is, the relationship of the wait time of the sensor 8 = the distance between the carriage sensors / the carriage speed is obtained.

The present invention includes a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for discharging ink, particularly in an ink jet printing method. The present invention provides an excellent effect in a print head and a printing apparatus of a type in which a change in the state of ink is caused by energy. This is because such a method can achieve higher density and higher definition of the print.

The typical configuration and principle are described, for example, in US Pat. Nos. 4,723,129 and 4,740.
It is preferable to use the basic principle disclosed in the specification of Japanese Patent No. 796. This method is a so-called on-demand type,
Although it can be applied to any type of continuous type, in particular, in the case of the on-demand type, it can be applied to a sheet holding liquid (ink) or an electrothermal converter arranged corresponding to the liquid path. Applying at least one drive signal corresponding to the printing information and providing a rapid temperature rise exceeding nucleate boiling, causing the electrothermal transducer to generate thermal energy, causing film boiling on the heat-acting surface of the printhead. This is effective because bubbles can be formed in the liquid (ink) corresponding to this drive signal on a one-to-one basis. The liquid (ink) is ejected through the ejection opening by the growth and contraction of the bubble to form at least one droplet. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of a liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. If the conditions described in U.S. Pat. No. 4,313,124 relating to the rate of temperature rise of the heat acting surface are adopted, more excellent printing can be performed.

As the configuration of the print head, in addition to the combination of the discharge port, the liquid path, and the electrothermal converter (linear liquid flow path or right-angled liquid flow path) as disclosed in the above-mentioned respective specifications, A configuration using U.S. Pat. No. 4,558,333 or U.S. Pat. No. 4,459,600 which discloses a configuration in which the heat acting portion is arranged in a bending region is also included in the present invention. In addition, Japanese Unexamined Patent Application Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal converter for a plurality of electrothermal converters, and an aperture for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration is based on JP-A-59-138461, which discloses a configuration corresponding to a discharge unit. That is, according to the present invention, printing can be performed reliably and efficiently regardless of the form of the print head.

Further, the present invention can be effectively applied to a full line type print head having a length corresponding to the maximum width of a print medium that can be printed by a printing apparatus. As such a print head, a configuration that satisfies the length by combining a plurality of print heads,
Any one of the structures as a single print head integrally formed may be used.

In addition, even in the case of the serial type as described above, a print head fixed to the apparatus main body or an electric connection with the apparatus main body or ink from the apparatus main body by being attached to the apparatus main body. The present invention is also effective when a replaceable chip-type print head that can be supplied or a cartridge-type print head in which an ink tank is provided integrally with the print head itself is used.

It is also preferable to add a print head discharge recovery means, preliminary auxiliary means, and the like as the configuration of the printing apparatus of the present invention, since the effects of the present invention can be further stabilized. Specifically, heating is performed on the print head using capping means, cleaning means, pressurizing or suction means, an electrothermal converter, another heating element, or a combination thereof. Pre-heating means for performing the pre-heating and pre-discharging means for performing the discharging other than the printing can be used.

Further, the type and the number of the print heads to be mounted are, for example, one for one color ink.
In addition to those provided with only a plurality of inks, a plurality of inks may be provided corresponding to a plurality of inks having different print colors and densities. That is, for example, the print mode of the printing apparatus is not limited to the print mode of only the mainstream color such as black, but may be any of a print head integrally formed or a combination of a plurality of print heads. The present invention is also very effective for an apparatus provided with at least one of the full-color print modes using mixed colors.

In addition, in the embodiment of the present invention described above, the ink is described as a liquid.
An ink that solidifies at room temperature or below and softens or liquefies at room temperature may be used, or the ink jet method controls the viscosity of the ink by adjusting the temperature of the ink itself within the range of 30 ° C to 70 ° C. In general, the temperature is controlled so that is within the stable ejection range, and therefore, a liquid in which the ink is in a liquid state when the use print signal is applied may be used. In addition, in order to positively prevent temperature rise due to thermal energy by using it as energy for changing the state of the ink from a solid state to a liquid state, or to prevent evaporation of the ink, the ink is solidified in a standing state and heated. May be used. In any case, the application of heat energy causes the ink to be liquefied by the application of heat energy according to the print signal and the liquid ink to be ejected, or to start solidifying when it reaches the print medium. The present invention is also applicable to a case where an ink having a property of liquefying for the first time is used. In such a case, the ink is held in a state of being held as a liquid or solid substance in the concave portion or through hole of the porous sheet as described in JP-A-54-56847 or JP-A-60-71260. Alternatively, it may be configured to face the electrothermal converter. In the present invention, the most effective one for each of the above-mentioned inks executes the above-mentioned film boiling method.

In addition to the above, the printing apparatus of the present invention may be used as an image output terminal of an information processing apparatus such as a computer, a copying apparatus combined with a reader or the like, or a facsimile apparatus having a transmission / reception function. May be adopted.

[0096]

As described above, according to the present invention,
As in the conventional case, the timing of ink ejection and the time until the detection sensor is stabilized are expected, and the complicated operation of controlling by software control can be omitted. This improves the reliability of the software, that is, the reliability of the device.

Further, since the software control is simplified, the processing time of the CPU can be spared, which can be allocated to other software processing. This is also effective in increasing the speed of the entire system.

Further, since the software control is simplified, it is possible to use an inexpensive CPU which is slightly slower, unlike the conventional case where only a CPU capable of high-speed processing is used. Cost reduction is possible.

Further, by providing a home position sensor of the carriage without providing a new photo sensor for detecting ink non-ejection, the cost of the apparatus is not increased.

In a preferred embodiment, the position of the two carriages can be determined by using two carriage position sensors. The advantage over the other embodiments is that the size of the flag can be reduced. If the flag to be attached to the carriage or the head is too large, the degree of freedom in mechanical design is limited, which is advantageous in improving the degree of freedom in mechanical design.

Further, the fact that the distance between the two carriage sensors is easily increased (there is a limit to the enlargement of the flag), there is room for selection of the moving speed of the carriage. There is also an effect that the speed of the carriage can be determined in terms of noise.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a facsimile apparatus as an embodiment of a printing apparatus according to the present invention.

FIG. 2 is an enlarged perspective view of a printing unit in the facsimile machine shown in FIG.

FIG. 3 is a block diagram of a control unit of the facsimile apparatus shown in FIGS. 1 and 2;

FIG. 4 is an operation flowchart of the facsimile apparatus including an ink non-discharge detection operation.

FIG. 5 is a schematic diagram showing a printing unit in the facsimile machine shown in FIG.

FIG. 6 is a control flowchart supplementing a non-ejection detection operation of the printing apparatus of the present invention.

FIGS. 7A to 7C are schematic diagrams of a non-ejection detection operation in the printing apparatus of the present invention, wherein FIGS. 7A and 7B are front views, and FIG. 7C is a side view. .

8A and 8B are schematic diagrams of a non-ejection detection operation in another embodiment of the printing apparatus of the present invention, where FIG. 8A is a front view, and FIG. 8B is a side view. is there.

FIG. 9 is a sectional view of an example of a conventional printing apparatus.

FIG. 10 is a schematic diagram of a non-ejection detection operation.

FIG. 11 is a block diagram of software processing of a printing unit in the facsimile machine.

[Explanation of symbols]

A reading unit B print unit C paper feed unit F ink discharge direction G paper feed direction (sub-scan direction) H carriage movement direction (main scan direction) P print paper (print medium) S original 1 paper feed tray 2 paper feed roller 3 retard Roller 5 Print head 5a Ink ejection port array 6 Discharge roller 8 Ink ejection detection photosensor (ink ejection abnormality detection means) 15 Carriage 15a Butting portion 15b Light shield plate (flag) 16 Guide rod 17 Pulley 18 Timing belt 19 Flexible cable Reference Signs 20 cap 21 photo sensor (carriage position detecting means) 21a first photo sensor (carriage position detecting means) 21b second photo sensor (carriage position detecting means) 23 spur 24 control unit 25 CPU 26 ROM 27 RAM 28 A D conversion circuit 30 Carriage motor 31 Print motor 32 Motor drive circuit 33 Motor drive circuit 41 Document tray 45 Separation piece 46 Separation roller 48 Reading sensor 49 White roller 51 Document ejection tray 52 Reading motor 53 Motor drive circuit 54 Printer interface 55 Line control circuit

Claims (10)

[Claims] 1. A printing apparatus that performs printing using a print head that discharges ink onto a print medium based on image data, wherein the ink detects abnormal ink discharge when the print head discharges ink. A discharge abnormality detection unit, at least one carriage position detection unit for detecting a position of a carriage on which the print head is mounted, and an ink discharge detection process by the ink discharge abnormality detection unit based on a detection result by the carriage position detection unit. And a control unit for starting the printing apparatus. 2. While the carriage moves from a first position to a second position distant from the first position, based on a detection result by the carriage position detection means that detects movement of the carriage, 2. The printing apparatus according to claim 1, wherein the detection by the ink discharge abnormality detection means and the discharge of the ink from the print head are started with a time difference. 3. The method according to claim 2, wherein the time difference between the start of the detection by the ink discharge abnormality detecting means and the start of the ink discharge is a time required for the ink discharge abnormality detecting means to be sufficiently stable for the detection. 2. The printing device according to 2. 4. The apparatus according to claim 3, wherein the time during which the ink discharge abnormality detecting means is stabilized from the start of driving is a time when the ink discharge abnormality detecting means is electrically, optically, or thermally stabilized. Printing device. 5. When the detection state of the carriage position detection means is A or B, the position of the carriage when the detection state changes from A to B is set to the first position, and the detection state is set to B. 3. The printing apparatus according to claim 2, wherein the position of the carriage when changing from A to A is a second position. 6. The time difference (t) from the first position to the second position is determined by setting a length of a position detection flag attached to the carriage or the print head to L, and a moving speed of the carriage. Is υ, t = L ÷ υ
3. The printing apparatus according to claim 2, wherein: 7. A printing apparatus according to claim 1, wherein said carriage position detecting means is arranged near said ink discharge abnormality detecting means. 8. When the ink discharge is detected by the ink discharge abnormality detecting means, the ink droplet at the start of the ink discharge lands at a position short of the ink discharge abnormality detecting means, and the carriage is positioned at a second position. The position of the ink ejection port array is L, where L is the distance between the carriage position detection means and the ink ejection abnormality detection means.
8. The distance L1 is defined as L = L1 + L2, where L1 is the distance between the discharge start position and the ink discharge abnormality detection means and L2 is the distance between the ink discharge port array and the rear end of the flag. The printing device according to the above. 9. The apparatus according to claim 1, wherein said carriage position detecting means includes a first detecting means for detecting said first position, and a second detecting means for detecting said second position. 2. The printing device according to 2. 10. The time difference (t) from the first position to the second position is represented by a distance L between the first detecting means and the second detecting means, and a moving speed of the carriage. 10. The printing apparatus according to claim 9, wherein when is set to υ, t = L ÷ υ.