JPH0445942A - Ink jet recorder - Google Patents

Abstract

PURPOSE:To prevent effectively an occurrence of a curl of a material to be recorded regardless of the type of the material to be recorded even when a large quantity of striking ink is used for images by providing means for enforcing the material to be recorded to have projecting and recessed cross section in the direction approximately perpendicular to the conveying direction of the material at the time of delivery of the material after recording, and controlling the enforcing means according to the type of the material to be recorded. CONSTITUTION:A material to be recorded 23 on which an image is recorded at a record head is delivered while being enforced to have a projecting and recessed cross section in the direction perpendicular to the conveying direction. Such an enforcement is performed by delivering the material to be recorded 23 to a tray 27 through a roller 30 consisting of paper delivery upper rollers in tandem 28 and paper delivery lower rollers in tandem 29 arranged in staggered form in the direction of paper width. It is enforced to have projecting and recessed cross section in the direction perpendicular to the conveying direction even when a curl is to be formed with a recording face outside due to striking with a large quantity of ink and expansion of the recording face.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inkjet recording apparatus that performs recording by ejecting ink from a recording head onto a recording material.

(Prior Art) Recording devices such as printers, copiers, and facsimile machines record images consisting of dot patterns on sheet-like recording materials such as paper and thin Plasdec thin plates based on image information. It is configured.

The recording device may be an inkjet type,
It can be divided into wire dot type, thermal type, laser beam type, etc. Among them, inkjet type (inkjet recording apparatus) is configured to perform recording by ejecting ink onto a recording material.

Inkjet recording apparatuses have advantages such as low noise because they are non-impact type, and the ability to easily record color images using multicolored inks.

In this inkjet recording device, images are formed using liquid, so if the recording material is a liquid-absorbing material such as paper, the expansion of the recording surface causes curling (warping) with the recording surface facing outward when the paper is ejected. This may result in poor stacking performance on the paper discharge tray.

Therefore, as a conventional method to prevent this curl,
LJ with forced direction to curve the recording surface inward when paper is ejected
A method has been adopted to do this.

(Technical problem to be solved by the invention) However,
With the conventional forced application method, when recording with a large amount of droplets (ink ejection volume), such as color recording, the recording material loses its stiffness, and this, combined with the expansion of the recording surface due to droplet injection, causes the forced application. Even after the paper is attached, there is a problem in that the recording material curls on the paper ejection tray with the recording surface facing outward when the paper is ejected.

This curling is noticeable when the recording material loses its stiffness immediately after being ejected, and even if the paper is ejected while forming a reverse loop at the time of ejecting, the recording material without stiffness will immediately turn the recording surface outward. This causes curling, which makes it difficult to handle the recording material and causes paper jams at the paper discharge section.

Furthermore, when using a recording material that is inherently strong, such as 0I (P film), if it has poor water absorption or has a slow water absorption rate, the forcible attachment may actually distort the recorded image. .

The present invention has been made in view of such conventional technical problems, and it is possible to effectively prevent curling of recording materials, regardless of the type of recording material, even in the case of images that require a large amount of ink to be deposited. An object of the present invention is to provide an inkjet recording device that can improve handling, eliminate paper jams, and increase the versatility of recording materials.

(Means for Solving the Problems) The present invention provides an inkjet recording device that performs recording by ejecting ink from a recording head onto a recording material, and when discharging the recording material after recording, the A means for forcibly attaching the recording material is provided so that the cross section in a direction substantially perpendicular to the conveying direction has an uneven shape, and the forcibly attaching means is controlled according to the type of the recording material. By doing this, even in the case of images that require a large amount of ink, regardless of the type of recording material, curling of the recording material can be effectively prevented, improving handling and eliminating paper jams. The present invention provides an inkjet recording device that can enhance the versatility of recording materials.

[Example〕 Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 5 is a longitudinal sectional view showing an example of the configuration of an inkjet recording apparatus to which the present invention is applied.

In the fifth article, 10 is a part of a scanner that reads a document and converts it into an electrical signal.

The converted signal is given to the recording head section 21 of the recording section (inkjet recording device section) 20 as a drive signal.

Sheet-shaped recording materials 23, such as paper or thin plastic plates, stored in the case 1-22 are sent out sheet by sheet toward the heald conveyance section 24 along the guide means 34 in the direction of arrow A, when necessary.

An image is recorded on the recording material 23 by the recording/rad section 21 when it passes through the belt conveyance section 24 , and is sent out to a paper discharge tray 27 via a fixing section 25 and a paper discharge section 26 .

A pair of paper discharge rollers 30 including a paper discharge roller 28 and a paper discharge lower roller 29 are provided in the paper discharge section 26 .

Note that 31 is a recovery cap section, which has a function of keeping the recording head section 21 in a recordable state at all times.

Here, in the recording head section 21, a plurality (for example, four) of line-type recording heads are disposed in which the ejection ports are multiplied in a line shape and are elongated to the extent that they cover the paper width of the recording material. High-speed full color recording is possible.

In the case of full color, these recording heads 33A, 33B, 33C133D can be recording heads that use cyan, magenta, yellow, and black inks, for example.

The recording head 33 (any one of the recording heads 33A to 33D, or all of them) is an inkjet recording head that ejects ink using thermal energy, and is an inkjet recording head that ejects ink using thermal energy. It is equipped with a converter.

Further, the inkjet recording heads 33A to 33D perform recording by ejecting ink from ejection ports by the growth of bubbles due to film boiling caused by thermal energy applied by the electrothermal converter.

In the scanner part 10, 11 is a document, and 12 is a document scanning unit that scans the document.

The original scanning unit I/12 includes a rod array lens 13.
, 1-magnification color separation line sensor (color image sensor)
14, an exposure means 15 is built-in.

At least the document scanning unit 12 scans the document 11 on the document table.
When moving and scanning in the direction of arrow B to read an image, the exposure lamp in the exposure means 15 in the document scanning unit 1-12 is turned on, and the reflected light from the document 11 is guided by the rod array lens 13 to produce color information. The light is focused on a same-magnification color separation line sensor (hereinafter referred to as a reading sensor) 14, which is a reading sensor, and reads the color image information of the original 11 for each color, and converts it into an electrical digital signal.

This digital signal is sent to the recording section 20.

Drive signals based on these signals are supplied to the recording heads 33A to 33D for each color, ink is ejected, and an image is formed.

FIG. 6 shows the recording head 33 (the recording head 3 in FIG. 5).
3A to 33D (representing an arbitrary recording head); FIG.

In FIG. 6, a predetermined gap (for example,
Discharge port surface 3 facing each other with a distance of about 0.5 to 0.8 mm)
6, a plurality of discharge ports 37 are formed at a predetermined pitch in the vertical direction, and both:j! An electrothermal converter (thermal energy generator such as a heating resistor) 4 as a discharge heater is installed along the wall surface of each liquid path 39 that communicates the liquid chamber 38 and each discharge port 37.
0 is placed.

Each discharge heater 40 is activated based on the image signal (recorded information).
is driven (energized) to generate bubbles in the ink in the liquid path 39, and the pressure of the bubbles forms flying ink droplets, causing the ink droplets (dots) to adhere to the recording material 23 while recording. Let's do it.

Therefore, according to the present invention, in an inkjet recording apparatus that performs recording by discharging ink from the recording head 33 onto the recording material 23, when the recording material 23 is ejected after recording, the conveyance of the recording material 23 is carried out. A means for forcibly attaching the recording material 23 is provided so that the cross section in a direction substantially perpendicular to the direction has an uneven shape, and the means for forcibly attaching the recording material 23 is determined based on the type (size, material, etc.) of the recording material 23. An inkjet recording apparatus is provided which is characterized in that it is controlled according to.

First Embodiment: FIG. 1 is a schematic perspective view showing the paper discharge state in the first embodiment of the inkjet recording apparatus according to the present invention, and FIG. 2 is a schematic perspective view of the paper discharge section in the embodiment of FIG. FIG. 2 is a schematic perspective view showing the configuration.

In FIGS. 1 and 2, the recording material 23 on which an image has been recorded by the recording head section 21 is forcibly attached so that the cross section in the direction perpendicular to the conveyance direction C becomes uneven (or wave-shaped). It is discharged.

As shown in FIG. 2, this forced attachment is performed by passing the recording material through a pair of paper ejection rollers 30 consisting of a comb-shaped upper paper ejection roller 28 and a comb-shaped lower paper ejection roller 29 arranged in a staggered manner in the paper width direction. 23 onto the paper ejection tray 27.

Note that 28A and 29A in FIG. 2 indicate the roller shafts of the upper paper discharge roller 28 and the lower paper discharge roller 29, respectively.

According to this embodiment, in a color inkjet recording device 20 or the like as shown in FIG. 5, a large amount of ink is injected, and the recording surface (the upper surface of the recording material 23 in FIG. 1) expands, so that the recording surface Even if a curl is formed with the outer side being formed, the stiffness of the recording material 23 is improved to the desired strength because it is forcibly attached so that the cross section in the direction perpendicular to the conveying direction C has an uneven shape as shown in the figure. After being ejected, the recording material 23 can be prevented from curling on the paper ejection tray 27, and the stacking performance can be improved.

In the inkjet recording device 20, the recording material 23
is generally fed at a speed of about 100 mm/sec, for example.

Therefore, the maximum amount of printing by the recording head section 21 is set to 2.
When recording a high-density image on the entire surface using five colors, the recording material 23
This results in a loss of stiffness and a tendency to curl with the recording surface facing outward.

While the back surface of the recording material 23 is placed along the guide plate or the like in this state, curling of the recording material 23 can be suppressed.

However, when the paper is released from the guide plate, such as during paper ejection, it curls.

Therefore, as described above, a desired number of comb-shaped upper rollers 28 and lower rollers 29 are placed in a staggered manner (with mutual axes) as shown in FIG. By arranging the recording material 23 with shifted directions, it is possible to forcibly strengthen the stiffness of the recording material 23 in the conveyance direction, and it is possible to overcome the curling force caused by surface expansion.

In this way, even when paper is ejected and on the paper ejection tray 27,
The recording material 23 could be kept in a straight state (flat state).

By the way, with the above configuration, when recording an image on a thin plastic plate such as an OHP film that hardly curls even when a large amount of ink is applied, it may cause roller marks on the surface of the recording material or roller offset. It may occur.

Therefore, in this embodiment, a means is provided in the recording apparatus to detect whether the recording material 23 used is OHP film, BPF (bank print film), etc., and when these are detected or selected, the recording material 23 is ejected. By widening the distance between the upper paper roller 28 and the lower paper discharge roller 29, the pressure force acting on the recording material 23 is reduced.

Second Embodiment; FIG. 3 is a schematic front view showing a configuration example of a paper discharge section in a second embodiment of an inkjet recording apparatus according to the present invention.

Since various sizes are used as the recording material 23, it is required to be configured so that the above-mentioned effects can be reliably achieved for any of these sizes of recording materials.

Therefore, in this embodiment, by moving the axial direction (paper width direction) positions of the upper paper ejection roller 28 and the lower paper ejection roller 29 according to the size, the recording material 23 is always
The paper is ejected with both side edges of the paper being forced upward.

In FIG. 3, when adopting a sheet feeding configuration that matches the center part a of the recording material 23 depending on the type of recording material 23 (for example, B5 size to A3 size), the sheet is fed with B5-A3 vertically. When paper is to be fed, the paper rollers 2B and 29 are arranged as shown in FIG. 2
8. Move the rollers 29 to change the roller arrangement as shown in FIG. 3(B).

In this way, by controlling the positions of the paper ejection rollers 28 and 29 according to the feeding direction of the recording material 23, the edges of both sides of the recording material 23 can be adjusted regardless of the size of the recording material used. The recording material 23 can be forcibly attached upward.
An inkjet recording device was obtained in which both side edges of the inkjet recording device were not bent or caught in the conveyance path.

Third Embodiment: FIG. 4 is a schematic front view showing a configuration example of a paper discharge section in a third embodiment of an inkjet recording apparatus according to the present invention.

In this embodiment, the upper paper ejection roller 28 and the lower paper ejection roller 29 constituting the paper ejection roller pair 30 are each formed of nine rollers.

These comb-shaped paper ejection upper roller 28 and paper ejection lower roller 29 are constructed by inserting eccentric crank-shaped shafts 28A and 29A into the centers of the rollers. There is an uneven shape (as shown in the figure) between
A staggered paper passing section is formed.

In this embodiment, the roller 29B at the left end of the lower paper discharge roller 29 is rotationally driven by being rotated by a driving force from a conveying means (not shown) (belt conveying section 24 in FIG. 5).

Further, the rollers forming the lower paper discharge roller 29 are connected to each other by a joint roller 29C so that rotational force can be transmitted, and when the left end roller 29B rotates, the other rollers also rotate as a result.

In this way, the comb-shaped lower paper discharge rollers 29 are configured such that each roller rotates (rotates) in the conveying direction.

FIG. 4A shows the arrangement of the pair of paper discharge rollers 30 when recording materials 23 of each size of B4, B5, A3, and A4 are passed in the vertical direction.

Figure 4 (B) shows B5 and A4 size recording materials 2.
The arrangement of the paper ejection row 30 when paper is passed horizontally is shown, and this arrangement is obtained by rotating the upper and lower eccentric shafts 28A and 29A by 180 degrees from the arrangement of (A) in Fig. 4. be.

By controlling the rotational position according to the size of the recording material as shown in (A) and (B) in Figure 4, it is possible to always force both side edges upward in all sizes. .

FIG. 4C shows a state in which the eccentric shafts 28A and 29A of the upper and lower discharge rollers 28, 29 are rotated 90 degrees from the state shown in FIG. 4A.

As mentioned above, in this example as well, OHP film B
When recording on PF (back print film), etc., there is almost no curling even if a large amount of ink is applied. Therefore, with the roller arrangement of (A) and (B) in Figure 4, the surface of the recording material is roller marks or roller offset may occur.

Therefore, in this embodiment, a means is provided in the recording apparatus to detect whether the recording material 23 used is OHP film, BPF (pack print film), etc., and when these are detected or selected, the recording material 23 is ejected. The upper paper roller 28 and the lower paper discharge roller 29 eccentric shafts 28A and 29B are rotated approximately 90 degrees from the state shown in FIG. 4(A), and the state shown in FIG. 4(C) is
The sheet passing portion between the upper and lower conveyance rollers 28 and 29 is controlled to be approximately linear as shown in FIG.

By adopting the above-described configuration, it is possible to forcibly attach the recording material 23 with a desired pressure depending on the size and material of the recording material 23 so that the cross section in the direction perpendicular to the conveying direction has an uneven shape, and the recording material 23 can be ejected. An inkjet recording device capable of preventing subsequent curling was obtained.

Furthermore, even if the sizes of the recording materials 23 are different, simply by controlling the rotational positions of the roller shafts 28A and 29B, it is possible to always forcibly attach both edges of the recording materials 23 upward. An inkjet recording device was obtained in which both side edges of the inkjet recording device 23 can be prevented from being bent or caught in the conveyance path.

Furthermore, even if the material of the recording material 23 is different, the forced attachment of the recording material 23 can be done under the appropriate conditions (including the case where the recording material 23 is not forcibly attached by simply passing the paper) by simply controlling the rotational positions of the roller shafts 28A and 29B. Thus, an inkjet recording apparatus was obtained which can prevent roller marks from forming on the surface of a recording material and roller offset from occurring.

In each of the above embodiments, the types of the recording material 23 are different in size and material. Even when the characteristics are different, the same implementation can be performed and the same effect can be achieved.

In the above embodiments, the present invention is applied to a line type recording head 33 that covers the recording area in the paper width direction of the recording material 23.
Although the description has been given using an example of application to a line-type inkjet recording apparatus 20 using A to 33D, the present invention is also applicable to a serial scan-type inkjet recording apparatus using a recording head mounted on a carriage, etc. The present invention can be similarly applied to inkjet recording apparatuses using other recording methods, and similar effects can be achieved.

Further, in the above embodiment, four recording heads 33A to 3
Although the case of a full-color inkjet recording device using 3D has been described, the present invention is applicable to monochrome recording using one recording head, or gradation recording using multiple recording heads with the same color but different densities. Regardless of the number of recording heads, such as an inkjet recording device (it can be applied in the same way and can achieve the same effects).

The present invention provides particularly excellent effects in inkjet recording apparatuses using the bubble jet recording head proposed by Canon Co., Ltd., such as Infusiera 1.

As for typical configurations and principles thereof, it is preferable to use the basic principles disclosed in, for example, US Pat. No. 4,723,129 and US Pat. No. 4,740,796.

This method can be applied to both the so-called on-demand type and the continuous type, but especially in the case of the on-demand type, it is necessary to place the liquid (ink) on the sheet or liquid path where it is held. By applying at least one drive signal to the electrothermal transducer that corresponds to the recorded information and causes a rapid temperature rise exceeding nucleate boiling,
This method is effective because it generates thermal energy in the electrothermal transducer to cause film boiling on the heat-active surface of the recording head, resulting in the formation of bubbles in the liquid (ink) in one-to-one correspondence with this drive signal.

Due to the growth and contraction of these bubbles, liquid (
ink) to form at least one droplet.

If this drive signal is in the form of a pulse, bubble growth and contraction will occur immediately and appropriately, so liquids with particularly excellent responsiveness (
Ink) can be ejected, which is more preferable. As this pulse-shaped drive signal, those described in US Pat. No. 4,463,359 and US Pat. No. 4,345,262 are suitable.

Further, if the conditions described in US Pat. No. 4,313,124 concerning the temperature increase rate of the heat acting surface are adopted, even more excellent recording can be achieved.

The configuration of the recording head includes, in addition to the combined configuration of ejection ports, liquid paths, and electrothermal converters (straight liquid flow path or right-angled liquid flow path) as disclosed in the above-mentioned specifications, a heat acting section. US Pat. No. 4,558,333 and US Pat. No. 4,459,600 disclose a configuration in which the
The present invention also includes a configuration using the specification of the above specification.

In addition, Japanese Patent Application Laid-open No. 123670 of 1982 discloses a configuration in which a slit that is located in common with a plurality of electrothermal converters is used as a discharge part of the electrothermal converters, and an open source that absorbs pressure waves of thermal energy is disclosed. The present invention is also effective with a configuration based on Japanese Patent Application Laid-Open No. 138461 of 1982, which discloses a configuration in which holes correspond to discharge portions.

Furthermore, as a full-line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the recording apparatus, the length can be increased by combining multiple recording heads as disclosed in the above-mentioned specification. Either a configuration that satisfies the above requirements or a configuration as a single recording head formed integrally may be used, but the present invention can more effectively exhibit the above-mentioned effects.

In addition, a replaceable chip-type recording head that is attached to the device body enables electrical connection to the device body and ink supply from the device body, or a chip-type recording head that is installed integrally with the recording head itself. The present invention is also effective when a cartridge type recording head is used.

Further, it is preferable to add recovery means, preliminary auxiliary means, etc. for the recording head, which are provided as a configuration of the recording apparatus of the present invention, because the effects of the present invention can be further stabilized.

Specifically, these include capping means, cleaning means, pressure or suction means, preheating means for the recording head using an electrothermal transducer or another heating element, or a combination thereof. It is also effective to perform a preliminary ejection mode in which ejection is performed separately from printing in order to perform stable printing.

Furthermore, the recording mode of the recording device is not limited to a recording mode of only mainstream colors such as black, but may also include a recording mode in which the recording heads are configured integrally or by a combination of multiple colors, or multiple colors of different colors, or The present invention is also extremely effective for devices equipped with at least one full color by color mixture.

In the embodiments of the present invention described above, the ink is explained as a liquid, but it is an ink that solidifies at room temperature or lower, and is softened or liquid at room temperature, or in the above-mentioned inkjet, the ink itself is heated at 30 degrees. C or above 70°C
Generally, the temperature is adjusted within the following range so that the viscosity of the ink is within the stable ejection range, so it is sufficient that the ink is in a liquid state when the recording signal is applied.

In addition, the temperature increase caused by thermal energy can be actively prevented by using it as energy for changing the state of the ink from a solid state to a liquid state, or the ink that solidifies when left standing is used to prevent ink evaporation. In any case, the ink may be liquefied by applying thermal energy in accordance with the recording signal and ejected as liquid ink, or it may already begin to solidify when it reaches the recording material. It is also applicable to the present invention to use ink that is liquefied only by thermal energy.

In such a case, the ink is held as a liquid or solid in the recesses or through-holes of the porous sheet and is held facing the electrothermal converter, as disclosed in Japanese Patent Application Laid-Open No. 54-56847. It is also possible to take a form like this.

In the present invention, the most effective method for the above-mentioned ink is the one that implements the above-mentioned film boiling method.

[Effects of the Invention] As is clear from the explanation below, according to the present invention, in an inkjet recording apparatus that performs recording by ejecting ink from a recording head onto a recording material, the recording material is ejected after recording. At the time of recording, a means for forcibly attaching the recording material is provided so that the cross section of the recording material in a direction substantially perpendicular to the conveying direction has an uneven shape, and the means for forcibly attaching the recording material to the recording material is Since the configuration is configured to control according to the type of recording material, even in the case of images with many ink spots, regardless of the type of recording material,
An inkjet recording apparatus is provided that can effectively prevent curling of a recording material, improve handling, eliminate paper jams, and increase the versatility of the recording material.

[Brief explanation of the drawing]

FIG. 1 is a partial perspective view schematically showing the paper discharge state in the first embodiment of the inkjet recording apparatus according to the present invention, and the second is a schematic diagram showing the configuration of the paper discharge section of the inkjet recording apparatus of FIG. 3 is a partial perspective view, FIG. 3 is a schematic partial front view showing the structure of a paper discharge section of a second embodiment of the inkjet recording apparatus according to the present invention, and FIG. 4 is a third embodiment of the inkjet recording apparatus according to the present invention. FIG. 5 is a longitudinal sectional view illustrating an inkjet recording apparatus to which the present invention is applied, and FIG. 6 is a schematic diagram illustrating the structure of the recording head in FIG. 5. Target 9 is a perspective view of the arch. Below, symbols representing main components in the drawings are listed. 20 =-recording section (inkjet recording device), 21-
m-recording head section, 23 =-recording material, 24th bell general feed section, 26-=-paper discharge section, 27''--paper discharge tray, 2
8-- Upper paper roller, 29-- Lower paper discharge roller, 3
0---Pair of paper discharge rollers, 33.33A to 33 D-11 recording head, 37---Discharge port, 39 liquid path, 40 -
Discharge heater (electrothermal converter).

Claims (3)

[Claims] (1) In an inkjet recording device that performs recording by ejecting ink from a recording head onto a recording material, after recording,
A forcing means is provided for forcibly attaching the recording material so that the recording material has an uneven cross section in a direction substantially perpendicular to the conveying direction when the recording material is discharged; An inkjet recording device characterized in that the inkjet recording device is controlled according to the type of recording material. (2) A claim characterized in that the recording head is an inkjet recording head that ejects ink using thermal energy and is equipped with an electrothermal converter for generating thermal energy. Item 1. The inkjet recording device according to item 1. (3) The inkjet recording apparatus according to claim 2, wherein the recording head discharges the ink from the discharge port by the growth of bubbles due to film boiling caused by the thermal energy applied by the electrothermal converter. .