JP2915605B2 - Ink jet recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus, for example, an ink jet recording apparatus having functions such as a facsimile, a copying machine or a printer, and an ink jet apparatus used as an output device such as a multifunction machine or a workstation having the functions. It relates to a recording device.

[0002]

2. Description of the Related Art The non-impact recording method has recently attracted attention in that the generation of noise during recording is extremely small to a negligible level. Among them, an ink jet recording method which has a possibility of high-speed recording and can perform recording on so-called plain paper without requiring a specific fixing process is an extremely effective recording method.

A recording head applied to an ink jet recording apparatus generally has a fine liquid discharge port (orifice), a liquid path, an energy acting section provided in a part of the liquid path, and a liquid acting in the energy acting section. An energy generating means for generating droplet forming energy to be generated.

[0004] As an energy generating means for generating such energy, a recording method using an electromechanical transducer such as a piezo element or the like, an electromagnetic wave such as a laser is irradiated, and the liquid there absorbs the electromagnetic wave to generate heat. And a recording method using an energy generating means for discharging and flying droplets by the action of the heat, or an energy generating means for discharging the liquid by heating the liquid by an electrothermal converter such as a heating element having a heating resistor. There is a recording method using the like.

Among them, a recording head used in an ink jet recording method for discharging a liquid by thermal energy has a high density liquid discharge port (orifice) for discharging a recording droplet to form a flying droplet. Since they can be arranged, it is possible to record at a high resolution.

[0006] Among them, a recording head using an electrothermal transducer as a thermal energy generating means can easily be made compact as a recording head as a whole, and has made a remarkable improvement in technology and reliability in recent semiconductor fields. Technology and micro-machining technology can be fully utilized, and it is easy to make it multi-nozzle and high-density mounting because it can be easily made longer and more planar (two-dimensional). It is possible to provide an inkjet recording head with good productivity and low production cost, and an apparatus having this head.

In general, an ink jet recording head manufactured through a semiconductor manufacturing process using an electrothermal transducer as an energy generating means is provided with a liquid path corresponding to each orifice. An electrothermal converter is provided as means for applying thermal energy to the liquid filling the path to discharge the liquid from the corresponding orifice to form flying droplets. In addition, the liquid paths are configured such that liquid is supplied from a common liquid chamber communicating with each liquid path.

Conventionally, as shown in FIG. 13, a head block in which a plurality of recording heads for ejecting ink can move between a recording position and a recovery position by a first moving means, as shown in FIG. 7X, a recording head unit (recording head unit) 1X, and a pair of registration rollers 6X for transporting the recording medium.
6Y, a belt transport unit 4X, and a recovery cap unit (recovery cap unit) 2X that can be moved between a standby position and a recovery position by a second moving unit. And
After the recording suspension period or the like, the recording head unit 1X and the recovery cap unit 2X are moved to the respective recovery positions, whereby the respective recording heads are capped by the recovery cap unit 2X, and the idle discharge mode is selected when the recording operation is ON. When the power to the apparatus main body is turned on or after a long standby state, the ink pressure circulation mode is selected and the ink pressure circulation is performed.

The recording paper sensor 5X is provided in the vicinity of the fixing paper discharge section 3X remote from the recording head unit 1X.
During recording, the recording medium is moved to the pair of registration rollers 6X and 6X.
The recording medium is detected by the recording paper sensor 5 within a predetermined time elapse set in the controller from the time when the recording paper sensor 5 is detected.
X, the controller determines that a stagnation (jam) of the recording medium has occurred, and
A command for stopping the conveyance unit including X is output to the drive source of the conveyance unit, and the recording operation of each recording head is stopped. Even when the stagnation occurs, the recording head unit 1X and the recovery cap unit 2X are held at the recording position and the standby position, respectively, so that the recording heads are not capped, and the stagnation is caused by the recording head unit 1X. When the error occurs in the vicinity, the operator moves the belt transport unit 4X downward to provide a required space between the recording head unit 1X and the belt transport unit 4X, thereby performing the staying process.

[0010]

In the conventional ink jet recording apparatus described above, the recording head unit is held at the recording position even if a stagnation (jam) of the recording medium occurs during recording, and each recording head is moved. Since the configuration is not capping, there are problems as described below.

During the staying process, the ink in the nozzles of each print head thickens, and ink ejection failure occurs during printing after the process, thereby deteriorating printing quality. In addition, when recording is performed using coated paper or BPF (back print film) paper in addition to plain paper as a recording medium, especially when the stagnation occurs near the recording head unit, paper floating in the air Powder and coat powder enter the nozzles of each recording head, causing clogging of the nozzles.

Further, since the recording paper sensor is provided at a position further away from the recording head unit, if the above-mentioned stagnation occurs near the recording head unit, the time when the stagnation actually occurred and the stagnation are detected by the controller. Therefore, the difference between the time at which the actual retention has occurred and the time at which the recording operation of each recording head is stopped by the controller is also long. As a result, a large amount of ink is ejected from each recording head and adheres to the transport belt and other members, and thus there is a problem in that the processing takes a lot of time and labor.

The present invention has been made in view of the above-mentioned problems of the prior art.
When the recording medium stays, the recording head is automatically capped to prevent the ink in the nozzle from thickening and prevent paper dust and coated paper from entering the nozzle, thereby improving the recording quality. It is an object of the present invention to provide an ink jet recording apparatus having improved image quality.

In addition to the above objects, the invention according to claim 2 provides an ink jet recording apparatus in which the amount of ink adhering to a conveyor belt and other members is reduced, and the time and labor required for the processing are reduced. The purpose is to:

[0015]

In order to achieve the above-mentioned object, the present invention provides an ink jet recording head which discharges ink by arranging a plurality of ink jet recording heads in a conveying direction of a recording medium. In an ink jet recording apparatus for forming a plurality of ink jet recording areas corresponding to each of the heads, a recovery unit including a cap for capping each of the plurality of ink jet recording heads, and the plurality of ink jet recording heads are formed by the ink jet recording. A head moving means for moving a head to a recording position for performing ink-jet recording on the recording medium by the cap, and a capping position for capping the ink-jet recording head by the cap; Detecting means for detecting the recording medium when the recording medium passes upstream of the ink jet recording head in the transport direction, and a predetermined means which is set in advance when performing recording. Control means for controlling the head moving means so as to move the plurality of inkjet recording heads from the recording position to the capping position when the recording medium is not detected by the detection means within a time period, The detection means and the ink jet recording head are alternately arranged in order from the upstream side in the transport direction.

[0016]

Further, the control means causes the recovery means to execute a recovery process in the idle discharge mode as the ink jet recording head is moved to the capping position, or moves the ink jet recording head to the capping position. The recovery means performs recovery processing in the ink pressurizing and circulating mode with the movement, or the recovery means moves the ink jet recording head to the capping position, and causes the recovery means to execute the idle discharge mode and the ink application mode. A recovery process in the pressure circulation mode may be executed.

The ink jet recording head is a full line type in which a plurality of ejection ports are provided over the entire width of the recording area of the recording medium, or ejects ink using thermal energy. An electrothermal converter for generating thermal energy may be provided.

[0019]

According to the first aspect of the present invention, the recording medium is sequentially conveyed to the ink jet recording head, where the recording is performed, and then the recording medium is discharged, but the recording medium is jammed for some reason. In this case, the control unit can detect the stagnation because the recording medium is not detected by the detection unit within a predetermined time set in advance by the control unit. After the detection, the control means controls the head moving means to move each of the plurality of ink jet recording heads from the recording position to the capping position. Here, since the detecting means and the ink jet recording heads are alternately arranged in order from the upstream side in the conveying direction of the recording medium, any one of the plural ink jet recording areas arranged in the conveying direction of the recording medium. Even if the recording medium stays due to conveyance failure, the time when the stay actually occurred,
Since the difference between the time when the stay is detected by the control means is short, that is, the time lag is short, the time when the stay actually occurs and the time until the printing operation (ejection operation) of the print head is stopped by the control means. And the difference becomes shorter.

[0020]

According to the second aspect of the present invention, after the capping, the control means causes the recovery means to execute the recovery processing in the idle discharge mode, whereby the idle discharge operation of the ink jet recording head is automatically performed. In the third aspect of the present invention, after the capping, the control means causes the recovery means to execute the recovery processing in the ink pressure circulation mode, whereby the ink pressure circulation operation of the ink jet recording head is automatically performed.

In the invention described in claim 4, after the capping, the control means causes the recovery means to execute the recovery processing in the idle discharge mode and the ink pressurizing and circulating mode, so that the idle discharge operation of the ink jet recording head and the ink The pressurized circulation operation is performed automatically.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the ink jet recording apparatus of the present invention will be described with reference to the drawings. First, the overall configuration of the first embodiment of the ink jet recording apparatus will be described with reference to FIG.

The ink jet recording apparatus having a copying function comprises a printer section 14 and a scanner section 17 installed above the printer section 14. The upper surface of the scanner section 17 is a document table on which a glass plate is fitted, and the document 15 is placed with its image side face down.
Below the glass plate, a document scanning unit 16 in which an exposure unit 16a, a rod eye lens 16b, and a 1: 1 color separation line sensor 16c are respectively disposed is arranged inside a scanner unit 17 in the direction of arrow A and in the direction opposite thereto. It is mounted so that it can reciprocate.

The original 15 is scanned by the original scanning unit 16.
Is read, the original scanning unit 16
Illuminates the image of the original 15 by turning on the exposure lamp of the exposure means 16a and moves and scans in the direction of arrow A from the position shown in FIG. The light is guided by the lens 16b and condensed on the same-size separation line sensor 16c. The same-size separation line sensor 16c reads the image of the document 15 as color-specific image information and converts it into an electric digital signal. The electrical digital signal is transmitted to a recording head unit 10 which is a recording unit for each color of the printer unit 14 described later.

On the other hand, at the bottom of the printer unit 14, a paper feed cassette 9 for storing cut paper, which is a recording medium cut to a predetermined size, is detachably mounted. Is provided with a manual feed portion 8 for manually supplying the recording medium. Between each of the paper feed cassette 9 and the manual feed unit 8 and a later-described transport belt unit 1, there are a plurality of feed paths for feeding the recording medium from the paper feed cassette 9 or the manual feed unit 8 to the transport belt unit 1. And a pair of rollers and a guide plate. A pair of registration rollers 7a, 7 that finally feed the recording medium out of the plurality of pairs of rollers.
b, the recording medium is guided at predetermined timing by the guide plates 6a,
The sheet is sent out toward the conveyor belt section 1 along 6b.

A plurality of guide plates and a pair of rollers are arranged in a row on the left side of the conveyor belt unit 1 in the figure, and a recording medium on which an image has been recorded is transferred from the conveyor unit 1 to the fixing and discharging unit 12. It is configured to pass through and be discharged to the tray 13. A recording paper sensor 5A is provided in the vicinity of the fixing paper discharge unit 12 as in the related art. Reference numeral 11 denotes a known recovery cap unit as recovery means, which will be described later. The recovery cap unit 11 is for capping each recording head of the recording head unit 10.

Here, the transport belt unit 1 provided at the center of the printer unit 14 will be described with reference to FIG.

The transport belt 1a is a recording medium (recording paper)
13a has a width sufficient to convey 13a, and the rotating shafts which are rotatably supported at an appropriate distance are wound around a parallel driving roller 1b, driven roller 1c and two tension rollers 1d, 1e, It is under tension of 2-5 kg. The transport belt 1a is made of a chargeable material and is insulated from other portions, and its outer peripheral surface is a transport surface for attracting and transporting the recording medium 13a. Further, the transport belt 1a has a two-layer structure, and the transport surface side is an insulating layer having a volume resistance of 10 ¹² Ω · cm or more, and the inner peripheral side is a conductive layer having a volume resistance of 10 ⁸ Ω · cm or less. A platen 1f of an appropriate length is disposed immediately below the upper traveling path of the transport belt 1a in the drawing, and the transport surface of the transport belt 1a traveling on the platen 1f is configured to form a plane. ing.

The drive roller 1b, which is located on the left side in the figure, of the two drive rollers 1b and the driven roller 1c is connected to a drive source such as an electric motor (not shown) via well-known drive transmission means (not shown). The driving belt 1 is rotated in the direction of arrow B by the driving of the driving source, so that the transport belt 1a is rotated in the direction of arrow B. On the transport surface (outer peripheral surface) of the transport belt 1a,
The charging roller 1g of the charger 2 is in contact with the charging roller 1g. The charging roller 1g is made of a conductive material such as metal or conductive rubber, and has a width equal to or wider than the width of the transport belt 1a. Grounded. Conveyor belt 1a
A voltage of several hundreds to several thousand volts is applied to the transfer surface by the charger 2.

Next, details of the recording head unit mounted above the conveyor belt will be described with reference to FIG.

The recording head unit 10 has four full-line type recording heads 4a to 4d for recording an image by ejecting ink from ejection ports and attaching the ink to a recording medium 13a, and is arranged in the head block 3 with high accuracy. It was done. The head block 3 can be moved between a recording position and a recovery position by a first moving means, which will be described later, including a gear and the like. The first moving means includes a driving motor, a driving circuit for controlling the driving motor, and the like. It is operated by a driving means described later.

The recording heads 4a to 4d are connected to ink tanks (not shown) for storing inks of cyan, magenta, yellow, and black, respectively, and eject the inks of the recording heads 4a to 4d. The discharge port forming surface having a plurality of discharge ports arranged in parallel is the transport belt 1a.
At a position above the predetermined gap L from the transfer surface of the sheet.
As described above, the platen 1f is disposed directly below the traveling path on the upper side in the drawing of the transport belt 1a, and the transport surface of the transport belt 1a traveling on the platen 1f forms a flat surface, and L can be held accurately. Recording paper sensors 5a to 5d as detection means fixed to the head block 3 are respectively located on the sides of the recording heads 4a to 4d, and these four recording paper sensors 5a to 5d are connected to the transport belt. 1a, the recording medium 1 passing in front of the recording heads 4a to 4d
3a, which is connected to a controller (not shown) as a control unit, which will be described later. That is, the recording paper sensors 5a to 5d are arranged in the vicinity of the recording heads 4a to 4d, respectively. As shown in FIG. 2, the recording paper sensor and the recording head are sequentially arranged from the upstream side in the transport direction of the recording medium 13a. Are alternately arranged, the recording paper sensors 5a to 5d and the recording heads 4a to 4d are positioned.

Here, an example of one of the four recording heads 4a to 4d used in the above-described recording head unit will be described.

In FIG. 3, the recording head 4a is a full line type having a discharge port forming surface in which a plurality of discharge ports 31 are formed in a row over the entire width of the recording area of the recording medium. In order to discharge ink from the discharge ports 31, an electrothermal converter 30 for generating thermal energy to which an applied voltage is supplied is provided for each ink liquid path. Then, by applying a drive signal, heat energy is generated in the electrothermal transducer 30 to cause film boiling and form bubbles in the ink liquid path. The ink is ejected from each of the ejection ports 30 by the growth of the bubbles.

Next, the details of the recovery unit will be described.
This will be described with reference to FIG.

The recovery cap unit 11 is horizontally moved between a standby position and a recovery position by a known second moving means including a slide table, a rail, and the like. A recovery system container fixed to the slide table;
Is formed at the lower part of. The discharge ink port 25 is connected to a discharge ink tank (not shown) via a tube (not shown). The space inside the recovery system container 19 is divided into five spaces by four partition plates 24a to 24d, and ink absorbers 21a to 21d are arranged in the four spaces among them. These four
The two ink absorbers 21a to 21d are disposed at an interval equal to the interval between the four recording heads 4a to 4d,
As the material, RVF (polyvinyl resin), which is a highly water-absorbing sponge, is suitable, and a material having excellent durability may be used.

The four aperture members 23a to 23d are respectively driven by driving means (not shown) so that the ink absorbers 21a to 21d can be pressed against the holding members 22a to 22d. The absorbed ink can be squeezed out. The ink seal 20 serving as a lid is fixed to the upper end of the recovery system container 19.

In this embodiment, the recording head is normally
At the time of non-printing, the ink is left while leaving the ink inside the ink discharge port. A recovery cap unit having a cap that can be joined to the ejection port forming surface or the ejection port formation surface side of the recording head was provided, and when the recording was not performed, the cap and the recording head were joined to cover the recording head, so to speak. Evaporating the ink liquid in the liquid path by sealing from the surrounding atmosphere in this state, filling the air layer of the joint part with the vapor of the ink, and setting the space formed by the cap and the recording head to the saturated vapor pressure of the ink. In addition, the viscosity of the ink and the drying of the ink in the liquid path are prevented.

However, in the case where printing is paused in a low-humidity environment or for a long period of time, even if the above-described capping is performed to prevent the ink liquid in the liquid path from evaporating, the ink viscosity may increase. In some cases, it may not be possible to prevent non-ejection or unstable ejection of ink from the ejection ports during printing after the printing suspension period. In the present invention, the problem of whether or not ink is ejected for the first time after a pause is hereinafter referred to as a “first problem”. In order to solve this first problem, an ink circulating pressurizing means for driving a recovery pump to circulate and pressurize the ink and discharge the ink from all the ejection ports of the recording head is also used. When the state of non-discharge is slight, the entire energy generating means of the head is driven to perform the same ink discharge operation as that for recording on paper or the like. This is not ejection for performing image recording, and is hereinafter referred to as “idle ejection” in the present invention.

As described above, when the ink dries due to the non-recording state for a long time and the viscosity increases and the inside of the discharge port and / or the liquid path is fixed, the ink is pressurized and circulated, and In the case where the recording state is relatively short and the fixing state is slight, the recording head is restored to a state in which printing can be performed by idle discharge operation.

Next, a recording member suitably used in this embodiment will be described.

In the ink jet recording system, recording is performed by flying small droplets of a recording liquid called ink and attaching the droplets to the surface of a recording paper such as paper. It is necessary that the print is not blurred. Further, the ink adhered to the recording member is quickly absorbed into the inside thereof, and particularly, even when inks of different colors adhere to the same portion in a short time, there is no phenomenon of ink flowing out or bleeding. The spread of printing dots,
It is preferable that the characteristics be such that the sharpness of the image quality is not impaired.

These characteristics may not be sufficiently satisfied with copy paper called plain paper used in an electrophotographic copying machine or the like or other general recording paper. In these papers, printing with only one color or superimposing two colors often provides a satisfactory image quality to some extent. For example, when printing a full-color image by superimposing three or more colors of ink, as in the case of printing and recording, When the amount of ink adhering to the paper increases, there may be cases where a sufficiently satisfactory image quality record is not obtained.

In the ink jet recording apparatus of the present embodiment, paper satisfying the above-mentioned characteristics is disclosed in Japanese Patent Application Laid-Open No. 56-1485.
No. 83, it is preferable to use a recording member provided with a coating (for example, finely divided silica) on a base paper so as to obtain the above characteristics. The ink is deposited on the coated surface of the recording member.

Therefore, in this embodiment, when recording an image using three or more colors of ink for higher quality image recording, the image recording is performed using coated paper, one color or two colors of ink. In this case, non-coated paper (paper not coated above) is selected and used. However, it does not matter even if image recording is performed using one color or two colors of ink on coated paper.

Next, the mechanism for moving the head will be described with reference to FIGS. 5, 6 and 7A through 7C, which are schematic top views and schematic cross-sectional views of the main part of the printer section. I do.

FIGS. 5 and 6 show the printer unit viewed from the upper side in FIGS. 2 and 4, respectively, and FIG.
(C) to (C) are cross-sectional views. Reference numeral 26 denotes a recovery system unit drive section as drive means, which is composed of two first and second drive motors, and the first and second drive motors.
It comprises a first and a second drive circuit for controlling the drive of each drive motor. A belt pulley 2001 is fixed to the output shaft of the first drive motor,
The driving force of the driving motor is the same as the belt pulley 2001,
The data is transmitted to a head block driving unit 2004 as a first moving unit, which is a head moving unit, via a timing belt 2002 and a timing belt 2003. The head block driving unit 2004 is provided with a helical gear pair 2005 having a twist angle of 45 °, a spur gear 2006 and 2007, and a worm speed reducer 2008 for converting the driving direction into a right-angle direction, and input by a belt. The drive is finally transmitted to the rack gear 2009 via the spur gear train.
The drive of the rack gear 2009 is transmitted to the rack 2010 provided in the head block 3 and converted into the vertical movement of the head block 3.

The head block 3 is provided with cams 2011 and 2012 at its front and rear portions, respectively. The cams 2011 and 2012 move along the inner surfaces of the head block moving rails 2013 and 2014, respectively. Then, the recording head is moved in the vertical direction. As a result, the head block 3 can be moved only by driving from the drive source side due to the characteristics of the worm speed reducer 2008, and the head frame itself falls naturally due to the weight of the plurality of heads mounted in the head block 3. There is no such accident, and the position of the head block 3 can be fixed at the position where the driving of the motor is stopped.

FIGS. 7A to 7C are cross-sectional views of main parts of the head moving mechanism. The head stop position includes the head recovery position (capping position), printing (recording) position,
There are three retracted positions. 7A shows a recovery position (capping position), FIG. 7B shows a printing (recording) position, and FIG. 7C shows a retreat position. Each of these position detections is accurately performed by the light shielding plate 2021 provided on the head block 3 shielding the detection units of the sensors 51a to 51c arranged corresponding to the respective stop positions.

Next, the drive mechanism of the head recovery device will be described. As shown in FIGS. 5 and 6, a drive wire pulley 2015 is fixed to the output shaft of the second drive motor of the recovery system unit drive unit 26 described above, and the driving force of the second drive motor is transmitted to the drive wire pulley 2015. You. The driving wire pulley 2015 includes a driving wire 201.
6 are wound, and both ends of the wire are respectively connected to the recovery container 1 via tension pulleys 2017 and 2018.
9 is attached to a wire bridging member 2019 attached to 9.

The recovery system container 19 is slidable on a slide shaft 2020 via a slide bearing (not shown) on the rear side, and a slide roller 2030 slides on the rail 2031 on the front side. As a result, the drive from the recovery system unit drive unit 26 is converted into reciprocation of the recovery system container 19, and the recovery system container 19 is moved from the recovery position, that is, the capping position, to the retracted (standby) position. The stop position of the recovery system container 19 is the position shown in FIG. 6, that is, the recovery position, and the position shown in FIG. 5, that is, the retracted (standby) position (at the time of printing). Sensors (photo interrupters, etc.) in which provided light shielding plates (not shown) are arranged corresponding to respective stop positions.
The detection is accurately performed by shielding the detection unit from light.

Next, the control unit of this embodiment will be described.

As shown in FIG. 8, each of the recording heads 4a to 4d
The first, second, third and fourth predetermined times respectively corresponding to (see FIG. 2) are set in advance.
8, the recording medium 13a is detected within the first, second, third and fourth predetermined times from when the recording medium 13a is detected by the pair of registration rollers 7a and 7b (see FIG. 1).
If not detected by at least one of the recording paper sensors 5a to 5d, the first drive motor 52 issues a command to move the head block 3 and the recovery cap unit 11 to the recovery position.
And second driving circuit 5 of second driving motor 53
4 and 55, respectively.
Drive motor of the conveyance means including
The printing operation (ejection operation) of 4d is stopped. Here, the first, second, third and fourth predetermined times are longer as the latter.

Next, the image recording operation of this embodiment will be described in detail with reference to FIGS.

The image of the original 15 placed face down on the original platen on the upper surface of the scanner section 17 is read as image information of each color by the original scanning unit 16 and converted into an electric digital signal. Printer section 14
To the recording head unit 10. On the other hand, the recording medium 13a that has been sent from the paper feed cassette 9 or the manual feed unit 8 and has reached the registration rollers 7a and 7b is sent out toward the transport belt unit 1 along the guide plates 6a and 6b at a predetermined timing. The recording medium is attracted by the static electricity to the conveying surface of the rotating conveying belt 1a and passes below the discharge port surface of each recording head of the recording head unit 10 for each color. At this time, the recording heads are connected to the registration rollers 7a and 7b.
In accordance with the timing when the recording medium 13a is sent out, ink is ejected from the ejection port of each recording head based on the electric digital signal, and the image is recorded on the recording medium 13a moving while being attracted to the transport surface. Record The recording medium 13 a on which the image has been recorded passes through the fixing paper discharge unit 12 and is discharged to the tray 13. The recording of the image is performed on the surface opposite to the surface adsorbed on the transport surface of the recording medium 13a.

During recording of the image, the recording medium 13 is located upstream of the recording head unit 10 for some reason.
a occurs, the recording medium 13a does not pass in front of each of the recording heads 4a to 4d within a first predetermined time set in advance by the controller 18, and is not detected by the recording paper sensor 5a. Sends instructions for moving the recording head unit 10 and the recovery cap unit 11 to the recovery position, respectively, in the respective drive circuits 54, 5 of the first drive motor 52 and the second drive motor 53.
5 and stops the driving operation of the driving motor of the conveying means including the conveying belt unit 1 and the recording operation (ejection operation) of each of the recording heads 4a to 4d. Next, the controller 18 executes the head protection sequence described below by selecting the idle ejection mode, and performs the staying process during the execution.

That is, as shown in FIG. 9A, of the recording head unit 10 at the recording position and the recovery cap unit 11 at the standby position, first, the recording head unit 10 is raised to the head-up position. After being moved (see FIG. 9B), the recovery cap unit 1
1 is moved to the recovery position (see FIG. 9C). Next, the recording head unit 10 is lowered to perform unit closing, that is, capping (FIG. 10A).
And FIG. 4). As a result, the lower end of the head block 3 (see FIG. 2) is engaged with the ink seal 20 (see FIG. 4) of the recovery cap unit 11, and the ejection port forming surfaces of the recording heads 4a to 4d are spaced at a constant interval. Each of the ink absorbers 21a to 21d is exposed to an appropriate humid atmosphere formed by the recovery container 19, the ink seal 20, and the four partition plates 24a to 24d.

Thereafter, an arbitrary number of ink ejection pulses are given to all the nozzles of each of the recording heads 4a to 4d, and the ink droplets ejected from the ejection openings of each of the recording heads 4a to 4d absorb the respective inks. It is absorbed by hitting the bodies 21a to 21d. As a result, each of the recording heads 4a to 4a
The thickening of the ink in the nozzle d is prevented, and no ink non-discharge occurs during the next printing.

After the above idle discharge operation, the recording head unit 10 is raised and moved to the head-up position (FIG. 1).
0 (B)), on the other hand, after the recovery cap unit 11 is moved to the standby position (see FIG. 10 (C)), the recording head unit 10 is lowered to the recording position (see FIG. 9 (A)). ), Normal recording is performed in this state.

When the recording medium 13a stays on the downstream side of the recording head unit 10, the recording medium 13a is moved to the recording paper sensor 5A (FIG. 1) within a fifth predetermined time set in advance by the controller. ), The controller 18 issues a command to move the recording head unit 10 and the recovery cap unit 11 to the recovery position, respectively, in the first drive circuit 54.
And to the second drive circuit 55, respectively.
The driving motor of the conveying means including the belt conveying section 1a and the recording operation of each of the recording heads 4a to 4d are stopped. Next, the controller 18 executes the above-described head protection sequence by selecting the idle ejection mode.

Further, at the time of non-recording or after the recording suspension period,
As in the conventional case, the recording head unit 10 and the recovery cap unit 11 are moved to the recovery position to perform capping, and when the recording operation is ON, the idle discharge mode is selected to perform the idle discharge operation. At the time of input or after a long standby state, an ink pressurizing and circulating mode to be described later is selected to perform ink pressurizing and circulating.

According to this embodiment, each of the recording paper sensors 5a to 5a
5 d are provided near the recording heads 4 a to 4 d, respectively. Therefore, when the recording medium 13 a stays near the recording head unit 10, the time when the stay actually occurred and the time when the Because the difference from the time when is detected is short, that is, the time lag is short,
The difference between the time when the actual staying occurs and the time until the printing operation (ejection operation) of each of the print heads 4a to 4d is stopped by the controller 18 is shortened.

In this embodiment, the controller selects the idle-discharge mode and automatically performs the idle-discharge operation after the stagnant state of the recording medium is detected. However, the present invention is not limited to this. The ejection operation does not necessarily have to be performed.

Next, a second embodiment will be described.

When the controller 18 in the ink jet recording apparatus of the present embodiment detects that the recording medium 13a has stayed, the controller 18 issues a command to move the head block 3 and the recovery cap unit 11 to the recovery position, respectively. After output to the drive circuits 54 and 55 of the second drive motor 53, respectively, the ink pressurizing and circulating mode is selected. The other configuration is the same as that of the first embodiment. Next, regarding the operation of the present embodiment,
A description will be given with emphasis on the points different from those of the first embodiment.

The controller 18 controls the recording medium 13a.
Is detected, the recording head unit 10 and the recovery cap unit 11 are moved to the recovery positions, respectively, and the recording heads 4a to 4d are capped (see FIG. 10A and FIG. 11A). ).

In this state, since the ink pressurizing and circulating mode is selected by the controller 18, the ink absorbers 21a to 21d held at a fixed interval for each of the recording heads 4a to 4d are moved by moving means (not shown). The recording heads 4a to 4d are respectively raised and come into contact with the ejection port forming surfaces of the recording heads 4a to 4d.

In this state, ink is forcibly supplied to each of the recording heads 4a to 4d by ink supply pumps (not shown), and the inside of each of the recording heads 4a to 4d is pressurized. As a result, the ink in each of the recording heads 4a to 4d is circulated to remove bubbles therein, and pressurized ink droplets 26a to 26d are also discharged from the nozzles from the discharge ports. As a result, dust and the like adhering to each ejection port forming surface are also removed and cleaned together with the ejection ink. The ink ejected from the ejection port is temporarily removed from each ink absorber 21a.
To 21d, but the ink absorbers 21a to 21d
Are saturated with ink, the ink absorbers 21a to 21a
Ink droplets 26a to 26d fall into the recovery system container 19 from 21d, and the dropped waste ink is sent to the waste ink tank through the waste ink port 25 through the waste ink hose (FIG. 11B). reference). The pressurization circulation time, that is, the drive time of the supply pump is usually about 0.5 seconds to several seconds.
When the pressurized circulation is completed, the ink absorbers 21a to 21a-2
1d is separated from each of the recording heads 4a to 4d. In this state, when each of the aperture members 23a to 23d is driven, the ink absorbers 21a to 21a which are substantially saturated
21d is squeezed by the squeezing members 23a to 23d, and ink droplets 27a to 27d fall from the ink absorbers 21a to 21d (see FIG. 12A). As a result, the absorption capacity of each of the ink absorbers 21a to 21d is restored, and preparations are made for the next ink absorption. Next, each of the aperture members 23a to 23d returns to the standby position, and each of the ink absorbers 21a to 21d again comes into contact with each of the ejection port forming surfaces of each of the recording heads 4a to 4d (see FIG. 12B). As a result, in the state shown in FIG.
At this stage, the ink that has not been completely absorbed from each ejection port forming surface because 1d is almost saturated is completely cleaned by the contact of the ink absorbers 21a to 21d. is there. Thereafter, each of the ink absorbers 21a to 21d is lowered by the moving means and returns to the state shown in FIG.

After the above-described ink pressurizing and circulating operation, the recording head unit 10 is raised and moved to the head-up position (see FIG. 10B), while the recovery cap unit 11 is moved to the standby position. In this state, normal recording is performed (see FIG. 10C).

Also, during non-printing or after a printing pause, the printing head unit 10 and the recovery cap unit 11 are moved to the recovery position and capping is performed as in the conventional case, and the idle discharge mode is selected when the printing operation is ON. The idle press operation is performed, and the ink pressurizing and circulating mode is selected and the ink pressurizing and circulating is performed when the power to the installation main body is turned on or after a long standby state.

Next, a third embodiment will be described.

When the controller 18 of the ink jet recording apparatus of the present embodiment detects that the recording medium 13a has stayed, the controller 18 issues a command for moving the head block 3 and the recovery cap unit 11 to the recovery position, respectively. After the output to each of the drive circuits 54 and 55 of the second drive motor 53, the idle discharge mode and the ink pressurizing and circulating mode are sequentially selected. The other configuration is the same as that of the first embodiment.

In this embodiment, when the recording medium stays, after each recording head is capped,
The idle discharge operation described in detail in the first embodiment and the ink pressurizing and circulating operation described in detail in the second embodiment are sequentially performed, and the other operations are the same.

Further, during non-recording or after a recording pause period, the recording head unit 10 and the recovery cap unit 11 are moved to the recovery position and capping is performed as in the conventional case, and the idle discharge mode is selected when the recording operation is ON. The idle press operation is performed, and the ink pressurizing and circulating mode is selected and the ink pressurizing and circulating is performed when the power to the installation main body is turned on or after a long standby state.

In each of the above embodiments, the head block is provided with a plurality of (four) recording heads. However, the present invention is not limited to this, and the number of recording heads is one. The present invention can also be applied to the present invention, and correspondingly, only one recording paper sensor may be provided.
Although the recording head using an electrothermal converter as an energy generating means has been described in detail, the present invention is also applicable to an ink jet recording apparatus equipped with an electromechanical converter such as a piezo element or a recording head using an electromagnetic wave such as a laser. The invention can be applied. Further, the first moving means and the second moving means may be configured to operate using the driving force of the common driving means.

The present invention provides an excellent effect particularly in an ink jet recording apparatus provided with a bubble jet type recording head proposed by Canon Inc.

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. By applying at least one drive signal corresponding to the recording information and giving a rapid temperature rise exceeding nucleate boiling, heat energy is generated in the electrothermal transducer, and the film is heated on the heat-acting surface of the recording head. As a result, bubbles in the liquid (ink) can be formed in one-to-one correspondence with the drive signal, which is effective. By discharging the liquid (ink) through the discharge opening by the growth and contraction of the bubble,
Form at least one drop. 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. The driving signal in the form of a pulse is disclosed in U.S. Pat. Nos. 4,463,359 and 4,345,526.
Those described in the specification of No. 2 are suitable.
Further, if the conditions described in US Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

As the configuration of the recording head, in addition to the combination of a discharge port, a liquid path, and an electrothermal converter (a linear liquid flow path or a right-angled liquid flow path) as disclosed in the above-mentioned respective specifications, The present invention is also effective for a configuration using U.S. Pat. No. 4,558,333 or U.S. Pat. No. 4,459,600 which discloses a configuration in which a heat acting portion is arranged in a bending region. In addition, Japanese Unexamined Patent Publication (Kokai) No. 123670/1984 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 pressure waves of thermal energy. The present invention is also effective as a configuration based on Japanese Patent Application Laid-Open No. 59-138461, which discloses a configuration corresponding to a discharge unit.

Further, as a full-line type recording head having a length corresponding to the maximum recording medium width that can be recorded by the image recording apparatus, a combination of a plurality of recording heads as disclosed in the above-mentioned specification can be used. However, the present invention can more effectively exhibit the above-described effects, although it may be either a configuration satisfying the length or a configuration as a single recording head formed integrally.

In addition, a replaceable chip-type recording head which can be electrically connected to the apparatus main body or supplied with ink from the apparatus main body by being attached to the apparatus main body, or the recording head itself. The present invention is also effective when a cartridge type recording head provided integrally is used.

Further, it is preferable to add a preliminary auxiliary means or the like to the recording head provided as a configuration of the image recording apparatus of the present invention since the effect of the present invention can be further stabilized. To be more specific, a cleaning means, a preheating means using an electrothermal transducer or another heating element or a combination thereof, and a preliminary ejection mode for performing a different ejection from recording for the recording head. Is also effective for performing stable recording.

Further, the recording mode of the image recording apparatus is not limited to the recording mode of only the mainstream color such as black, and the recording head may be integrally formed or a combination of plural recording heads. The present invention is also very effective for an image recording apparatus provided with at least one of full colors by color mixture.

In the embodiments of the present invention described above, the ink is described as a liquid. However, the ink is solidified at room temperature or lower, and is softened or liquid at room temperature. Generally, the temperature is controlled within the range of not less than 70 ° C. and the temperature is controlled so that the viscosity of the ink is in the stable ejection range. Good. In addition, positively prevent the temperature rise due to thermal energy by using the energy of the state change of the ink from the solid state to the liquid state, or use ink that solidifies in a standing state to prevent evaporation of the ink. In any case, thermal energy such as one in which the ink liquefies and is ejected as an ink liquid by application of the thermal energy according to the recording signal, and one in which the ink already starts to solidify when reaching the recording medium. The use of an ink that liquefies for the first time is also applicable to the present invention. In such a case, the ink is disclosed in JP-A-54-56.
No. 847 or Japanese Unexamined Patent Publication No. Sho 60-71260, in which the porous sheet is opposed to the electrothermal converter in a state of being held as a liquid or solid substance in the concave portions or through holes of the porous sheet. It may be. In the present invention, the most effective one for each of the above-mentioned inks is
This is to execute the film boiling method described above.

[0085]

Since the present invention is configured as described above, the following effects can be obtained.

According to the first aspect of the present invention, the ink jet recording head is capped by the cap of the recovery means immediately after the recording medium stagnation occurs. The ink does not easily increase in viscosity, and paper powder, coat powder, and the like do not enter the nozzle, so that clogging of the nozzle can be prevented. As a result, no ink ejection failure occurs during printing after the above-described processing, thereby improving printing quality. Further, the ink adhered to the ejection port forming surface of the ink jet recording head does not drop onto the transport belt or other members, and further, during the processing, an operator's hand or clothes may touch the ejection port forming surface of the ink jet recording head. Since there is no contact, the hands and clothes are not stained with ink, and adverse effects such as clogging and impact are not exerted on the ink jet recording head. further,
Even when the recording medium stays near the ink jet recording head, the amount of ink adhering to the conveyor belt and other members is reduced, so that the time and labor required for processing the ink are reduced.

[0087]

Further, if the idle discharge operation or the ink pressurizing and circulating operation is performed after the capping, the recording quality after that is further improved, and the recovery operation is completed during the staying process. Can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of a first embodiment of an ink jet recording apparatus of the present invention.

FIG. 2 is a detailed view of a main part at the time of recording in FIG.

FIG. 3 is a detailed view of a main part of a recording head according to the embodiment.

FIG. 4 is a detailed view of a main part at the time of capping in FIG. 1;

FIG. 5 is a top view of FIG. 2;

FIG. 6 is a top view of FIG. 4;

FIG. 7 is a plan view of a driving unit of the recording head.

FIG. 8 is a block diagram of a control unit according to the present embodiment.

FIGS. 9A and 9B are diagrams showing states of respective processes of a recording head unit and a recovery cap unit during a capping operation, wherein FIG. 9A shows a head up, FIG. 9B shows a unit close, and FIG. 9C shows a head down. I have.

FIG. 10 is a view similar to FIG. 9, wherein (A) is a cap and head-up, (B) is a unit open, (C)
Indicates head down.

FIGS. 11A and 11B are diagrams showing respective processes of states of a recording head unit and a recovery cap unit during ink pressurization and circulation in a second embodiment, wherein FIG.
(B) shows a nozzle part pressurizing step.

FIG. 12 is a view similar to FIG. 11, wherein (A) shows a drawing step and (B) shows a contacting step.

FIG. 13 is an overall configuration diagram of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conveying belt part 1a Conveying belt 1b Drive roller 1c Followed roller 1d, 1e Tension roller 1f Platen 1g Charging roller 2 Charger 3 Head block 4a, 4b, 4c, 4d Recording head 5A, 5a, 5b, 5c, 5d Recording paper sensor 6a, 6b Guide plates 7a, 7b Registration rollers 8 Manual feed unit 9 Paper feed cassette 10 Recording head unit (recording head unit) 11 Recovery cap unit (recovery cap unit) 12 Fixing and discharging unit 13 Tray 13a Recording medium 14 Printer unit 15 Document 16 Document scanning unit 16a Exposure means 16b Rod eye lens 16c 1: 1 disassembled line sensor 17 Scanner 18 Controller 19 Recovery system container 20 Ink seals 21a, 21b, 21c, 21d Ink absorbers 22a, 22b, 22c, 2 d Holding member 23a, 23b, 23c, 23d Aperture member 24a, 24b, 24c, 24d Partition plate 25 Discharge port 26 Recovery system unit drive unit (drive unit) 26a to 26d, 27a to 27d Ink droplet 30 Electrothermal converter 31 Discharge ports 51a, 51b, 51c Sensor 52 First drive motor 53 Second drive motor 54 First drive circuit 55 Second drive circuit 2001, 2002 Belt pulley 2003 Timing belt 2004 Head block drive unit 2005 Helical gear pair 2006, 2007 Spur gear 2008 Worm reducer 2009 Rack gear 2010 Rack 2011, 2012 Cam 2013, 2014 Head block moving rail 2021 Light shield plate 2015 Drive wire pulley 2016 Drive wire 2017, 2018 Tensile Npuri 2019 wire hung member 2020 slide shafts 2030 slide rollers 2031 Rail L gap

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasushi Murayama 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Setsu Uchida 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inside (72) Inventor Tatsuo Mitomi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masaharu Nemura 3-30-2, Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor ▲ Taka ▼ Yasuyuki Naka 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-2-78566 (JP, A) JP-A-62-20068 (JP) , A) JP-A-2-231147 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B41J 2/175 B41J 2/165

Claims (6)

(57) [Claims] 1. An ink jet recording method comprising: arranging a plurality of ink jet recording heads for discharging ink along a conveying direction of a recording medium to form a plurality of ink jet recording areas corresponding to the respective ink jet recording heads in the conveying direction. In the apparatus, a recovery unit including a cap for capping each of the plurality of inkjet recording heads, and recording the plurality of inkjet recording heads to perform inkjet recording on the recording medium by each of the inkjet recording heads A head moving means for moving a position and a capping position for performing capping of each of the ink jet recording heads by the cap, and arranged near each of the plurality of ink jet recording heads. Detecting means for detecting the recording medium when passing the upstream of the ink jet recording head in the transport direction; and when performing recording, the recording medium is detected by the detecting means within a predetermined time set in advance. Control means for controlling the head moving means so as to move the plurality of ink jet recording heads from the recording position to the capping position when not detected, and the detecting means in order from the upstream side in the transport direction. An ink jet recording apparatus, wherein the ink jet recording heads are alternately arranged. 2. The ink-jet recording apparatus according to claim 1, wherein said control means causes said recovery means to execute a recovery process in an idle ejection mode in accordance with moving said ink-jet recording head to said capping position. . 3. The ink-jet apparatus according to claim 1, wherein said control means causes said recovery means to execute a recovery process in an ink pressurization circulation mode in accordance with moving said ink-jet recording head to said capping position. Recording device. 4. The control means causes the recovery means to execute a recovery process in an idle discharge mode and an ink pressurization circulation mode as the inkjet recording head is moved to the capping position.
3. The ink jet recording apparatus according to claim 1. 5. The inkjet recording head according to claim 1, wherein the inkjet recording head is a full line type in which a plurality of ejection ports are provided over the entire width of a recording area of the recording medium. apparatus. 6. The inkjet recording head according to claim 1, wherein the inkjet recording head ejects ink using thermal energy, and includes an electrothermal converter for generating the thermal energy. Item 6. The ink jet recording apparatus according to item 1.