JPH0444853A - inkjet recording device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an image forming section that forms an image on a recording medium by ejecting ink from an ejection port of a recording head, and an image forming section that forms an image on a recording medium in the image forming section. The present invention relates to an inkjet recording apparatus equipped with a roller that sends out an image.

[Prior Art] In a conventional inkjet recording apparatus, a recording medium such as a recording paper is sandwiched between the circumferential surfaces of a pair of conveyance rollers, and as the rollers rotate, the medium is conveyed onto a conveyance belt of an image forming section. The ink ejected from the ejection ports of the recording head adheres to the recording head while being moved by the conveyor belt, thereby forming an image.

Further, the pair of conveyance rollers has a function of determining a paper feed timing, which is the timing for sending the recording medium to the conveyance belt, and an ejection timing, which is the timing to discharge ink to the recording head, in addition to the functions of the pair of conveyance rollers. Some devices have a configuration in which the recording medium is sent onto a conveyor belt by registration rollers.

[Problems to be Solved by the Invention] In the conventional inkjet recording device described above, a paper jam or the like occurs during image formation, and the ink is not yet dry, such as on a recording medium where image formation is in progress. Media may need to be removed. in this case,
The recording medium is removed from the inkjet recording apparatus by being pulled back in the opposite direction to the direction in which it was sent out to the image forming section while being sandwiched between the circumferential surfaces of a pair of transport rollers or registration rollers. In this case, the recording medium”,
Another problem is that undry ink is not transferred to the circumferential surface of the conveyance roller or registration roller, and the recording medium is smeared when the ink sheet recording device is operated again after the recording medium is removed. There is.

Additionally, if ink is transferred to the circumferential surface of the registration roller, the ink may cause the registration roller and the recording medium to slip, impairing the registration roller's ability to determine paper feed timing and ejection timing. There is a problem with storing it away.

Furthermore, during image formation, the ink ejected from the recording head becomes a mist and floats, and is blown away from the image forming section by the wind inside the machine and onto the circumferential surface of the conveyance roller or registration roller. There is also the problem that the recording medium that is fed out by the conveyance roller or the registration roller becomes dirty.

The present invention has been made in view of the above-mentioned problems of the conventional technology, and removes stains on the conveyance roller or registration roller caused by transfer of ink from a recording medium, adhesion of ink mist, etc. It is an object of the present invention to provide an inkjet recording apparatus that can prevent a recording medium from being stained and does not impair the functions of registration rollers to determine paper feeding timing and ejection timing.

``Means for Solving the Problems'' The ink sheet recording apparatus of the present invention, which aims to achieve the above object, comprises an image forming section that forms an image on a recording medium by ejecting ink from a recording head. , an inkjet recording apparatus comprising a conveying roller for feeding the recording medium to the image forming section, wherein a cleaning means for removing ink adhering to the circumferential surface of the conveying roller is provided on the circumferential surface of the conveying roller. It is characterized by being provided in sliding contact with.

In addition, there is also a case in which the transport roller is a registration roller that has the function of determining the paper feed timing and the Kanoda timing in addition to the function of the transport roller.

The recording head ejects ink using thermal energy, and may be equipped with an electrothermal converter that generates the thermal energy, or eject ink over the entire width of the recording area of the recording medium. [It is also possible to use a full line type in which a square is formed.

[Function] In the inkjet recording apparatus of the present invention configured as described in 1-, the ink or ink mist adhering to the peripheral surface of the transport roller or registration roller is removed by the cleaning means, so that the ink or ink mist adhering to the peripheral surface of the transport roller or registration roller The ink or ink mist does not land on the recording medium that comes into contact with the circumferential surface of the roller and is sent to the image forming section.

[Example] An example of the inkjet recording apparatus of the present invention will be described based on the drawings.

First, a first example will be described.

As shown in FIG. 1, the inkjet recording apparatus of this embodiment includes a printer section 14 and a scanner section 17 installed at the negative side of the printer section 14.

The upper surface of the scanner section 17 is a document mounting table into which a glass plate is fitted, and the original g11B is placed with the image side facing down.

Below the glass plate, a document scanning unit 16 is provided with an exposure means 16a, a rod array lens 16bJ, and a same-magnification color separation line sensor 16c. It is attached so that it can be moved back and forth.

When the image of the original 15 is read by the original scanning unit 16, the original scanning unit 16 lights the exposure lamp of the exposure means t6a and moves in the direction of the arrow from the position shown in the figure while irradiating the image of the original N415 with light. During the movement and scanning, the reflected light from the image of the original 15 is guided by the rod array lenses 16b and focused on the same-magnification resolution line sensor 16C, and the same-magnification resolution line sensor 16c
The image on the original 15 is read as color-specific image information and converted into an electrical digital signal. This electrical digital signal is transmitted to an image forming section of the printer section 14, which will be described later.

On the other hand, at the bottom of the printer section 14 is a paper feed cassette 9 that stores cut paper, which is a recording medium cut into a predetermined size.
A manual feed tray 8 for manually feeding the recording medium 20 is mounted on the right side of the printer section 14 in the drawing.

On the right side of the paper feed cassette 9 in the drawing, there is a pair of paper feed rollers 21a, at least one of which is forcibly rotated.

21b are rotatably supported, and as the pair of paper feed rollers 21a and 21b rotate, the paper feed cassette 9
The recording medium pushed out is sandwiched and transported, and is sequentially guided between two curved guide plates and two pre-registration guide plates 2a and 2b, to a pair of registration rollers 1a.

1b. Further, on the left side of the manual feed tray 8 in the drawing, there is a pair of paper feed rollers 2.
A pair of manual feed rollers 22a having the same configuration as fa and 21b.
, 22b are rotatably supported, and the recording medium 20 fed to the manual feed tray 8 is the manual feed roller 22a.

22b is rotated, and is guided between two pre-registration guide plates 2a, 2b to be sent out to the pair of registration rollers la, lb.

The two front register guide plates 2a and 2b are spaced apart from each other as the recording medium advances in the feeding direction, and are adjacent to each other on the left side of each edge where the space between them narrows. The pair of registration rollers 1a and 1b are each rotatably supported, and at least one is forcibly rotated at a predetermined rotational speed.

By being forcibly rotated, the pair of registration rollers la and Ib pass between the two post-registration guide plates 7a and 7b while sandwiching the recording medium between their circumferential surfaces, and carry the recording medium to the image forming section, which will be described later. It has a configuration in which it is sent out onto a belt 11.

Here, the conveyance belt 11 that constitutes a part of the image forming section provided in the center of the printer section 14 will be explained. It is rotated in the direction of arrow B by forcing roller Ilb, which is placed on the left side in the drawing, to rotate in the direction of arrow B at a predetermined rotational speed. Further, the outer peripheral surface of the transport heald 11 is made of a material that can be charged, and is charged by a charging roller that rotates in contact with the outer peripheral surface to be charged, thereby attracting the recording medium by static electricity. It's coming.

Next, there are four recording heads 10a to 10 installed above the conveyor belt 11, which constitute the other parts of the image forming section.
0d will be explained.

Each of the recording heads 10a to 10d is a full-line type in which a plurality of ejection ports for ejecting ink are formed over the entire width of the recording area of the recording medium, and are separated by color (cyan, magenta, yellow, and black). Arranged in appropriate categories. The ejection port surface formed by the plurality of ejection ports of each of the recording heads 10a to 10d arranged in parallel is located at a position separated by a predetermined gap above the outer circumferential surface of the conveyance belt 11 during image forming operation, and When image formation is not performed, each recording head 10a-1 is moved by a known moving means.
0d is raised by being moved above the conveyor belt 11, and is covered by the recovery cap portion 12 that has moved in conjunction with the movement.

A plurality of guide plates and paired rollers are arranged in sequence on the left side of the conveyor belt 11 in the figure, and the recording medium on which an image has been formed is transferred from the conveyor belt 11 to the fixing sheet discharge section 18 by the fan 13. Pass while catching the wind and reach tray 19
It is configured to be discharged to

Next, two cleaning means 6a are provided for removing ink adhering to each peripheral surface of the pair of registration rollers la and lb.
, 6b will be explained.

In FIG. 2, the cleaning means 6a on the lower side of the figure will be explained first. It is a sponge made of PVF (polyvinyl formal) resin that has a high ability to absorb ink (for example, "Bel Eataco" manufactured by Kanebo Co., Ltd. is suitable). A certain absorption pad 5a has a rectangular parallelepiped shape with a width wider than the width of the recording medium 20, and a pad holder 3a has a C-shaped cross section and extends long in parallel to the rotation axis of the registration roller 1a. It is removably attached to the inside of the

Two holder holding members 4a (others not shown) are fixed to both ends of the pad holder 3a, and one end of each holder holding member 4a (others not shown) is connected to the rotation axis of the registration roller 1a. It is pivotally supported by the register front guide plate 2a so as to be rotatable around an axis parallel to the register. Each of the holster holding members 4a (the others are not shown) is biased in the direction of arrow C by a known biasing means using a spring or the like (not shown), and this bias causes the absorbent pad 5a to be exposed from the pad holder 3a. One surface is configured to press the circumferential surface of the registration roller 1a in the direction of arrow C.

The cleaning means 6a and the cleaning means 6b on the upper side of the figure have the same structure, and are made of the same material as the absorbent pad 5a.
The shaped absorbent pad 5b is removably attached to the inside of a pad holder 3b, which has two holder holding members 4b (others not shown) fixed to both ends thereof, which are pivotally supported by the front guide plate 2b. The peripheral surface of the registration roller 1b is pressed in the direction indicated by the arrow by a biasing means (not shown) exposed from the pad holder 3b.

Next, the image forming operation of this embodiment will be briefly explained.

The image of the original 15 placed with the image side facing down on the original placing table on the upper surface of the scanner section 17 is transferred to the original scanning unit 1.
6 as image information for each color, converted into an electrical digital signal, and sent to each of the recording heads 10a to 10d of the printer section 14. On the other hand, a pair of paper feed rollers 21a, 21b or a pair of manual feed rollers 22a,
22b, a pair of registration rollers la,
When the recording medium reaches lb, the recording medium stops for several milliseconds with its leading edge in contact with the contact area of the circumferential surfaces of the pair of registration rollers la and lb, and then the two post-registration guides are moved at a predetermined paper feeding timing. The recording heads 10a to 10d for each color are guided between the plates 7a and 7b and sent out toward the conveyor belt 11, and are attracted by static electricity onto the outer peripheral surface of the conveyor belt 11 rotating at a predetermined rotational speed. It passes below each discharge port surface. At that time, each recording head 1
0a to 10d eject ink from the ejection ports of each of the recording heads 10a to 10d based on the electrical digital signal in accordance with the ejection timing measured from the paper feeding timing to form an image on the moving recording medium. Record. The recording medium on which the image has been formed passes through the fixing paper discharge section 18 and is discharged to the tray 19. Note that image formation is performed on the surface of the recording medium opposite to the surface that is attracted to the outer peripheral surface of the conveyor belt 11.

To describe the effects of this embodiment, for example, if a paper jam or the like occurs during image formation and the ink is not yet dry, the recording medium 20 (see FIG. 2), which is in the middle of image formation, is Even if the ink is transferred from the recording medium 20 to the circumferential surface of the registration roller 1b when returning the bow in the E direction, the ink may be transferred from each recording head 10 during image formation.
Even if the ink ejected from a to 10d floats as ink mist and is blown away by the in-machine wind generated by the fan 13 and adheres to each peripheral surface of the pair of registration rollers la and lb, The ink and ink mist adhering to the respective peripheral surfaces of the registration rollers 1a and 1b are removed from the pair of registration rollers la.

As 1b rotates, each cleaning means 6 is removed from each peripheral surface thereof.
Since the ink is absorbed into the interior of the absorption pads 5a and 5b of the inks 5a and 6b, the newly supplied recording medium is not contaminated with ink or ink mist. Furthermore, since the pair of registration rollers la, lb and the recording medium do not slip due to the ink or ink mist, the pair of registration rollers Ia, lb reliably feed the recording medium at the predetermined paper feeding timing. each recording head 10
The ejection timings of a to 10d do not lag.

Furthermore, the absorption pad 5a of each of the cleaning means 6a, 6b,
Since the pad holders 5b are removably attached to each of the pad holders 3a and 3b, they can be replaced with new ones when the ink absorption capacity decreases.

In this embodiment, a sponge made of PVF resin is used for each of the absorption pads 5a and 5b, but the invention is not limited to this, and other materials may be used as long as they can remove ink and ink mist. May be used.

Next, a second embodiment of the present invention will be described.

As shown in FIG. 3(A), the cleaning means 36b of this embodiment
are provided only on the registration rollers 31b that are in contact with the surface of the recording medium 50 on which an image is formed (the upper surface in the figure).

The absorption pad 35b of the cleaning means 36b is detachably attached to the inside of a pad holder 33b having the same shape as that shown in the first embodiment, and two holders are provided at both ends of the pad holder 33b. Holding member 34b (others not shown)
are fixed in place. Each holder holding member 34
b (the others are not shown) are each attached to a rotation shaft 34c rotatably supported parallel to the rotational axis of the registration roller 31b via a torque limiter (not shown). The torque limiter is a known one that causes the rotating shaft 34c to idle relative to each boulder holding member 34b (the others are not shown) when a torque of a predetermined magnitude or more is applied. When idling in the direction of arrow G, one surface of the absorption pad 35b exposed from the butt holder 33b is pressed against the circumferential surface of the registration roller 31b in the direction of arrow H with a predetermined load, and conversely, the rotating shaft 34c is rotated in the direction of arrow G. When idling in the opposite direction, the pad holder 33b is rotated in the opposite direction to the direction of the arrow H to separate the negative surface of the absorbent pad 35b from the circumferential surface of the registration roller 31b and lock it with a stopper (not shown). There is. Further, the rotation of the rotation shaft 34c is inputted from a rotation manual gear 34d fixed by a key to an appropriate part outside the attachment part of the rotation shaft 34c to the holder holding member 34b.

As shown in FIG. 3(B), the registration roller 31b
An output gear 31 that meshes with the rotary input gear 34d is located at a portion of the registration roller shaft 31c extending from one end.
d is installed via the output one-way clutch 31e,
An input gear 31f that meshes with an output gear driven by a drive source such as an electric motor (not shown) is attached to a further outer part of the output gear 3Sd via a human-powered one-way clutch 31g.

The human-powered one-way clutch 31g is the input gear 31
When f is being rotated in the direction (direction of arrow F) in which the recording medium 50 is sent out toward the image forming section, the rotation is transmitted to the registration roller shaft 31c, and the rotation is transmitted to the registration roller shaft 31c.
rotate in the direction of arrow F, and conversely rotate the registration roller shaft 31.
The output one-way clutch 31e is a known one that has a function of allowing the register roller shaft 31c to idle relative to the manual gear 31f when c is rotated in the direction opposite to the direction of the arrow F, and the output one-way clutch 31e is Registration roller shaft 3
1c is rotated in the direction of arrow F, the registration roller shaft 31c is allowed to idle relative to the output gear 31d, and conversely, when the registration roller shaft 31c is rotated in the direction opposite to the direction of arrow F, This is a known device that has the function of transmitting rotation to the output gear 31d and rotating the output gear in the direction opposite to the direction of arrow F.

To explain the operation of the configuration described above, when the pair of registration rollers 31a and 31b send out the recording medium 50 toward the image forming section, the registration roller shaft 31
c idles in the direction of arrow F with respect to the output gear 31d, and the rotational driving force slightly transmitted to the output gear 31d is transmitted to the rotation shaft 34c via the rotation input gear 34d. The rotation shaft 34c is connected to the pad holder 33 of the absorbent bat 35b.
The rollers are idly rotated or stopped relative to each holder holding member 34b (the others are not shown) in a state where one surface exposed from b is separated from the circumferential surface of the registration roller 31b. Furthermore, when a paper jam or the like occurs and the recording medium 50 is pulled back in the direction of the arrow J, the registration roller shaft 31c is rotated in the direction opposite to the direction of the arrow F, and the rotation is caused by the ratio gear 31d and the rotary manual gear 34d. The rotation shaft 34c rotates in the direction of arrow G. This rotation shaft 34c is connected to the absorbent pad 35b.
One surface exposed from the pad holder 33b is pressed against the circumferential surface of the registration roller 31b in the direction of arrow H with a predetermined load, and the registration roller 31b rotates idly relative to each holder holding member 34b (the others are not shown).

The operation of the cleaning means 36b of this embodiment will be explained as follows.
Ink or ink mist adhering to the peripheral surface of the registration roller 31a located below the registration roller 31b in the figure is transferred to the peripheral surface of the registration roller 31b and then absorbed into the absorption pad 35b.

The points of this embodiment other than those described above are the same as those of the first embodiment, so the explanation thereof will be omitted.

The effect of this embodiment is that the negative surface of the absorption pad 35b presses the circumferential surface of the registration roller 3.1b only when the recording medium 50 is pulled back in the direction of the arrow J. Pad 35b has little wear. Other effects are the same as in the first embodiment.

Further, in each of the above-mentioned embodiments, an example was shown in which the registration roller was provided with a cleaning means. It is also possible to provide cleaning means having the same configuration as each cleaning means.

Next, an example of each recording head used in each of the embodiments described above will be briefly described.

In FIG. 4, the recording head 60 is a full line type in which a plurality of ejection ports 50 are formed in a row over the entire width of the recording area of the recording medium, and each of the ejection ports 5
In order to eject ink from zero, an electrothermal converter 40 that generates thermal energy to which an applied voltage is supplied is arranged for each ink liquid path. By applying a drive signal, the electrothermal transducer 40 generates thermal energy to cause film boiling and form bubbles in the ink liquid path. The structure is such that ink is ejected from each of the ejection ports 50 by the growth of the bubbles.

The present invention brings about excellent effects particularly in the bubble jet recording head and ink sheet recording apparatus proposed by Canon Co., Ltd. among ink jet recording systems.

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 arrange the liquid (ink) in accordance with the sheet and liquid path that hold it. As an electrothermal converter,
By applying at least one drive signal that corresponds to recorded information and provides a rapid temperature rise exceeding nucleate boiling, the electrothermal transducer generates thermal energy, causing a film to form on the thermally active surface of the recording head. This is effective because by boiling the liquid (ink), bubbles can be formed in the liquid (ink) in one-to-one correspondence with this drive signal. The growth and contraction of the bubble causes liquid (ink) to be ejected through the ejection opening to form at least one drop. It is more preferable to use this drive signal in a pulse form, since the growth and contraction of bubbles can be carried out immediately and appropriately, so that ejection of liquid (ink) with particularly excellent responsiveness can be achieved. As this pulse-shaped drive signal, those described in US Pat. No. 4,463,359 and US Pat. No. 4,345,262 are suitable. Incidentally, U.S. Patent No. 431 for the invention regarding the temperature increase rate of the heat acting surface
If the conditions described in specification No. 3124 are adopted,
Even better recording can be performed.

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 is also effective in the structure described in the specification. In addition, Japanese Patent Application Laid-open No. 123670 of 1982 discloses a configuration in which a common slit is used as a discharge part for a plurality of electrothermal converters, and a hole that absorbs pressure waves of thermal energy is disclosed. The present invention is also effective as a configuration based on Japanese Patent Application Laid-Open No. 138461 of 1981, which discloses a configuration in which a discharge portion corresponds to a discharge portion.

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 an inkjet 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 or recording head that is attached to the inkjet recording device body enables electrical connection with the inkjet recording device body and supply of ink from the inkjet recording device body. The present invention is also effective when using a cartridge type recording head that is integrally provided with the recording head.

Further, it is preferable to apply recovery means, preliminary auxiliary means, etc. to the recording head, which are provided as a component of the inkjet recording apparatus of the present invention, because the effects of the present invention can be further stabilized. Specifically, these are:
preheating means for the recording head by means of a cabin ink means, a cleaning means, a pressure or suction means, 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 recording heads that are configured integrally or a combination of multiple heads, multiple colors of different colors, or mixed colors. The present invention is also extremely effective for devices equipped with at least one full color image.

In each of 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°C. It is common to adjust the temperature within the above range of 70"C or less so that the viscosity of the ink is within the stable ejection range, but if the ink is in a liquid state when the recording signal is applied, Good.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 can be left to solidify to prevent evaporation. In any case, the ink is liquefied by applying thermal energy in accordance with the recording signal and is ejected as a liquid ink, or the ink already begins to solidify when it reaches the recording medium. The use of ink that is liquefied only by thermal energy is also applicable to the present invention. .

It may also be in a form in which it is held in a liquid or solid state in the recesses or through holes of the porous sheet and faces the electrothermal converter.In the present invention, for each of the above-mentioned inks. The longest one is one that implements the film boiling method described above.

[Effects of the Invention] Since the present invention is constructed as described above, it produces the following effects.

If a paper jam occurs during image formation and the ink is not dry, such as a recording medium that is in the middle of forming an indirect image, it is necessary to remove the recording medium. Even if undry ink on the medium is transferred to the circumferential surface of the transport roller or registration roller, or if ink mist floating in the inkjet recording device adheres to the circumferential surface of the transport roller or registration roller. Even if the ink and ink mist are removed by the liquid scavenging means, the recording medium that comes into contact with the peripheral surface of the conveyance roller or the registration roller and is sent to the image forming station is contaminated by the ink and ink mist. Furthermore, the function of the registration roller to determine the paper feeding timing and ejection timing is not impaired.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the configuration of the first embodiment of the present invention, and FIG.
The figure is a sectional view of a main part of the same embodiment, and FIG. 3 shows the configuration of a cleaning means of a second embodiment of the present invention, (A) is a sectional view of a main part of the cleaning means, and (B) is a sectional view of the main part of the cleaning means. FIG. 4 is a developed view of a gear train, and FIG. 4 is a perspective view of a recording head used in each embodiment of the present invention. 1 a, 1 b, 31 a, 31 b = registration roller,
2a, 2b, 32a, 32b---Register front guide plate, 3
a, 3b, 33b--pad holder, 4a, 4b, 34b----holder holding member, 5a, 5b
, 35b=-absorption pad, 6a, 6b, 36b---cleaning means, 7a, 7b--post-register guide plate, 8... manual feed tray, 9... paper feed cassette, 10a, ]Ob, ] Oc, 10d,
60---recording head, 11a, 111)---
-t7-ra, 13...Fan, 14...Printer section, 17...Scanner section, 18...Fixing sheet discharge section, 19...Tray, 20.50-...Recording medium, 21a, 21b---Paper feed roller, 22a, 22b---Manual feed roller, 31c"・Registration roller shaft, 31d...Rokegya, 31e...Output one-way clutch, 31f...Manual gear, 31g ...Input one-way clutch, 34c... Rotating shaft, 34d... Rotating human power gear. Patent applicant Canon Co., Ltd.

Claims (1)

[Claims] 1. An inkjet comprising an image forming section that forms an image on a recording medium by ejecting ink from an ejection port of a recording head, and a conveyance roller that sends out the recording medium to the image forming section. An inkjet recording apparatus, characterized in that a cleaning means for removing ink adhering to the circumferential surface of the conveying roller is provided in sliding contact with the circumferential surface of the conveying roller. 2. The inkjet recording apparatus according to claim 1, wherein the conveyance roller is a registration roller that has the function of determining sheet feeding timing and ejection timing in addition to the function of the conveyance roller. 3. The inkjet recording apparatus according to claim 1 or 2, wherein the recording head discharges ink using thermal energy and is equipped with an electrothermal converter for generating the thermal energy. . 4. The inkjet recording apparatus according to claim 1, wherein the recording head is a full-line type in which ejection ports are formed over the entire width of the recording area of the recording medium.