JP2914782B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a printer, a copying machine,
The present invention relates to an image forming apparatus such as a facsimile or a workstation including the same.

[0002]

2. Description of the Related Art As an image forming apparatus of this type, a recording means (recording head) is mounted on a carriage which reciprocates along a guide shaft provided in a main body of the apparatus, and the recording means is covered by a sheet such as a sheet of paper or a plastic sheet. An image is formed while moving (main scanning) along the recording material, and the recording material is fed in a direction intersecting (usually at right angles) each time image formation for one line is completed, thereby forming the image on the recording material. What has the structure which forms (records) an image on a recording material is used.

The recording means can be classified into an ink jet type, a wire dot type, a thermal type, a laser beam type, a daisy wheel type and the like according to a recording system.
The ink jet type is a type in which ink is ejected from a recording means (recording head) onto a recording material to perform recording, and the recording means can be easily made compact, and a high-definition image can be recorded at a high speed. Advantages such as being able to record on plain paper without requiring special processing, and being a non-impact type, there is little noise, and it is easy to form a color image using multicolor inks. have.

[0004] In particular, an ink jet type recording means for discharging ink by using thermal energy is an electrothermal converter, an electrode, and a liquid formed on a substrate through a semiconductor manufacturing process such as etching, vapor deposition, or sputtering. By forming a road wall, a top plate, and the like, a device having a high-density liquid path arrangement (discharge port arrangement) can be easily manufactured, and further downsizing can be achieved.

[0005]

However, in the above-mentioned conventional image forming apparatus, the recording means is reciprocated in the left-right direction for recording on the recording material, so that the guide shaft and the transport roller (paper feed roller) are used. It is necessary to have a length at least as long as the width of the recording material. When the width of the recording material increases, the size of the apparatus body also increases, and the dead space increases in order to reciprocate the recording means in a straight line. There was a problem of getting it. The present invention has been made in view of such technical problems, and an object of the present invention is to reduce the size of the apparatus by eliminating the dead space of the apparatus main body, and to extend the carriage in the rotational radius direction. By increasing the radius of rotation of the movement (main scanning) path of the recording means, recording can be easily performed even on a recording material having a large paper width, and conversely, when recording is performed on a recording material having a small paper width. By providing an image forming apparatus, it is possible to further reduce the size of the recording medium by contracting the carriage and to easily perform good image recording even on recording materials having different thicknesses. is there.

[0006]

In order to achieve the above object, an image forming apparatus according to the present invention has a carriage on which a recording unit is mounted at a front end thereof, which is capable of extending and contracting in a radial direction of rotation, thereby moving the recording unit. By rotating the carriage around a carriage axis, recording is performed on a recording material held on a circumference around the carriage axis.

[0007]

FIG. 1 is a perspective view of an essential part of an image forming apparatus suitable for applying the present invention, and FIG. 2 is a side view of the image forming apparatus shown in FIG. 1 and 2,
1 is a carriage, 2 is recording means (recording head) mounted on the tip of the carriage 1, 3 is a motor for driving the carriage, 4 is a carriage shaft fixed to the carriage 1,
Reference numeral 5 denotes a carriage guide, reference numeral 6 denotes a paper feed (conveyance) roller, and reference numeral 7 denotes a recording material such as paper or a plastic thin plate.
The carriage 1 is provided with a gear train 8 by the motor 3,
When the carriage shaft 4 is rotationally driven through the shaft 9, the carriage shaft 4 is rotated (for example, reciprocatingly rotated) around the carriage shaft 4.

The carriage guide 5 is an arc member centered on the carriage shaft 4, and has a tooth profile 11 formed on an inner peripheral surface thereof. On the other hand, a driven gear (idle gear) 10 that meshes with the tooth profile 11 of the carriage guide 5 is rotatably attached to the side surface of the carriage 1. The recording material 7 is held by a guide (not shown) at a position on a circumferential surface around the carriage shaft 4, and is fed in a direction parallel to the carriage shaft 4 by rotation of the transport roller 6. You.

The recording head 2 is provided with an electrothermal converter for generating thermal energy used for discharging ink. Specifically, the thermal energy generated by the electrothermal converter is provided. The ink is ejected from the ejection port based on a change in the state of the ink including the generation of bubbles due to film boiling in the ink. FIG. 3 is a perspective view schematically showing the structure of the recording head 2, and FIG. 4 is a partial vertical sectional view showing the structure of an ink ejection section of the recording head 2. 3 and 4, the recording material 7
A plurality of discharge ports 52 are formed at a predetermined pitch on a discharge port surface 51 facing the apparatus at a predetermined gap (for example, about 0.5 to 1.5 mm). Exit 52
An electrothermal converter (heat generating resistor or the like) 55 (FIG. 4) for generating energy for ink ejection is provided along the wall surface of each liquid path 54 communicating with the liquid passage 54. 1 and 2
In the image forming apparatus described above, the recording head 2 is arranged in such a manner that the plurality of ejection ports 52 are arranged in a direction intersecting the direction of rotation (main scanning direction) of the carriage 1.
It is attached to. In this way, the corresponding electrothermal transducer 55 is driven (energized) based on the image signal or the ejection signal to cause the ink 56 (FIG. 4) in the liquid passage 54 to film-boil, and the ejection port 52 is generated by the pressure generated at that time. The recording head 2 ejects ink from the recording head.

In the above configuration, when recording (image formation) is performed, the rotation of the motor 3 is transmitted to the carriage shaft 4 so that the carriage 1 moves along the carriage guide 5 along the carriage guide 5 around the shaft 4. By driving the recording means 2 based on the image information while moving along the main scanning (main scanning), an image is formed (recorded) on the recording material 7. At this time, the recording material 7 needs to be positioned on the circumference around the carriage shaft 4 and the recording head 2
After the recording of one line in the circumferential direction is performed, the paper feed roller 6 is driven to feed the recording material 7 by a specified amount.

According to the configuration example described above, since the recording means (recording head) 2 performs recording while moving along an arc path around the carriage shaft 4, the length of the carriage shaft 4 is determined by the length of the paper. It is not affected by the dimensions of the recording material 7, so that the space for moving the carriage 1 can be reduced as compared with the conventional serial type image forming apparatus, and the apparatus main body can be downsized. Was completed.

FIG. 5 is a schematic side view showing the structure of a main part of an embodiment of an image forming apparatus to which the present invention is applied. In the image forming apparatus according to the present invention, in the configuration described with reference to FIGS. 1 and 2, the carriage 1 is configured to be expandable and contractible in the rotational radius direction by a slide mechanism. The carriage 1 indicated by a solid line in FIG. 5 indicates a contracted (short) state, and the carriage 1 indicated by a two-dot chain line indicates an extended (long) state.
The embodiment of FIG. 5 is different from the configuration examples of FIGS. 1 and 2 in the points described above, but the other portions have substantially the same configuration. Corresponding portions are denoted by the same reference numerals, and their details are described. Description is omitted.

According to the embodiment shown in FIG. 5, the same effect as in the above-described configuration example, that is, the recording means (recording head) 2
Performs recording while moving along an arc path around the carriage shaft 4, the length of the carriage shaft 4 is not affected by the dimensions of the recording material 7 such as the paper width. Compared to the image forming apparatus of the type, the space for moving the carriage 1 can be reduced, and the effect that the size of the apparatus can be reduced can be obtained. Can be That is, by extending the carriage 1, it is possible to increase the radius of rotation of the movement (main scanning) path of the recording head 2, and therefore, the recording material 7 having a larger paper width than the configuration examples of FIGS. Can be recorded. Conversely, in the case of recording on a recording material having a small paper width, an effect is obtained in that the carriage 1 can be contracted to further reduce the size. Further, in the case of a thick recording material, for example, the distance between the recording material 7 and the recording head 2 can be properly maintained by contracting the carriage 1 in the rotational radius direction by an amount corresponding to the thickness, The effect that good image recording can be performed even on recording materials having different thicknesses can be obtained.

In the above configuration examples and embodiments, the case where an ink jet head is used as the recording means (recording head) 2 has been described. However, the present invention provides a wire dot head, a daisy wheel head, a thermal head, a laser beam, and the like. The present invention can be similarly applied to an image forming apparatus using another type of recording head such as a head, and can achieve the same operation and effect. Further, in the above configuration examples and embodiments, the case of an image forming apparatus using one recording head 2 has been described as an example, but the present invention includes a plurality of recording heads that perform recording in different colors. The same effects can be obtained regardless of the number of recording heads, such as a color image forming apparatus or an image forming apparatus for gradation recording using a plurality of recording heads having the same color but different densities. Can be achieved.

Further, in the case of the ink jet recording type, the recording means (recording head) 2 is a replaceable cartridge type recording means in which a recording head and an ink tank are integrated, or a recording head and an ink tank. Separately, recording means having various structures such as a recording means having a structure in which they are connected via a coupler and a tube can be used.

When the present invention is applied to an ink-jet type image forming apparatus, for example, it can be applied to an apparatus using a recording means (recording head) using an electromechanical transducer such as a piezo element. The present invention brings about an excellent effect in an image forming apparatus using a recording unit of a method of discharging ink by using thermal energy. According to such a method, it is possible to achieve higher density and higher definition of recording.

The typical configuration and principle are described in, for example, US Pat. Nos. 4,723,129 and 4,740.
Preferably, this is done using the basic principles disclosed in US Pat. This method can be applied to both the so-called on-demand type and the continuous type. In particular, in the case of the on-demand type, liquid (ink)
By applying at least one drive signal corresponding to the recorded information and providing a rapid temperature rise exceeding nucleate boiling to an electrothermal transducer arranged corresponding to the sheet or liquid path in which Then, heat energy is generated in the electrothermal transducer, and the film is boiled on the heat-acting surface of the recording means (recording head). As a result, bubbles in the liquid (ink) can be formed in one-to-one correspondence with the driving signal. It is valid.

The liquid (ink) is ejected through the ejection opening by the growth and contraction of the bubble to form at least one droplet. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of a liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable. As the pulse-shaped drive signal, US Pat.
Those described in 463359 and 4345262 are suitable. In addition, US Pat. No. 4,431,131 of the invention relating to the rate of temperature rise of the heat acting surface.
If the conditions described in the specification of JP-A No. 24 are adopted, more excellent recording can be performed.

As the configuration of the recording head, in addition to the combination configuration (a linear liquid flow path or a right-angled liquid flow path) of the discharge port, liquid path, and electrothermal converter as disclosed in the above-mentioned respective specifications, U.S. Pat. No. 4,558,333 and U.S. Pat.
A configuration using the specification of Japanese Patent No. 459600 is also included in the present invention. 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. That is, according to the present invention, the recording can be reliably and efficiently performed regardless of the form of the recording head.

Further, even in the case of the serial type as described above, the recording head fixed to the apparatus main body or the ink supply from the apparatus main body by being electrically connected to the apparatus main body by being attached to the apparatus main body. The present invention is also effective when a replaceable chip-type recording head which enables the recording or a cartridge-type recording head in which an ink tank is provided integrally with the recording head itself is used.

It is preferable to add recovery means for the printhead, preliminary auxiliary means, and the like provided as a configuration of the printing apparatus in the present invention since the effects of the present invention can be further stabilized. If you list these specifically,
For the recording head, a capping unit, a cleaning unit, a pressurizing or suctioning unit, a preheating unit using an electrothermal transducer or another heating element or a combination thereof, and a discharge other than recording. Performing the preliminary ejection mode is also effective for performing stable printing. Also,
Regarding the type or number of print heads to be mounted, for example, in addition to the one provided corresponding to a single color ink, a plurality of print heads are provided corresponding to a plurality of inks having different print colors and densities. It may be something. That is,
For example, the recording mode of the recording apparatus is not limited to a recording mode of only a mainstream color such as black, and may be any of a single recording head and a combination of plural recording heads. Alternatively, the present invention is extremely effective for an apparatus provided with at least one of full colors by color mixture.

In addition, in the embodiments of the present invention described above, the ink is described as a liquid. However, an ink which solidifies at room temperature or below and which softens or liquefies at room temperature, or an ink jet ink is used. In general, in the method, the temperature of the ink itself is adjusted within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range. What is necessary is just to be liquid. in addition,
Whether to positively prevent temperature rise due to thermal energy by using it as energy for changing the state of the ink from a solid state to a liquid state, or use ink that solidifies in a standing state to prevent evaporation of the ink In any case, the ink is liquefied by the application of the heat energy according to the recording signal, and the liquid ink is ejected,
The present invention is also applicable to a case where an ink having a property of being liquefied for the first time by thermal energy, such as one that starts to solidify when it reaches a recording medium, is used.

The ink in such a case is disclosed in
As described in JP-A-56847 or JP-A-60-71260, a form in which the liquid sheet or the solid sheet is opposed to the electrothermal converter while being held as a liquid or solid substance in the concave portion or through hole of the porous sheet. It may be. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, the form of the ink jet recording apparatus according to the present invention is not only one used as an image output terminal of an information processing apparatus such as a computer, but also a copying apparatus combined with a reader and the like, and a facsimile apparatus having a transmission / reception function. And the like.

[0025]

As is apparent from the above description, according to the image forming apparatus of the present invention (claim 1), the carriage on which the recording means is mounted at the leading end is made expandable and contractible in the rotational radius direction. A configuration in which a rotation radius of a moving path of a recording unit is adjustable and the carriage is rotated about a carriage axis to perform recording on a recording material held on a circumference around the carriage axis; Since the guide shaft of the carriage can be shortened, the size of the apparatus can be reduced by eliminating the dead space of the apparatus main body. In addition, the carriage can be extended in the radial direction of rotation to rotate the movement (main scanning) path of the recording means. By making the radius large, it is possible to easily record even on a recording material having a large paper width, and conversely, when recording on a recording material having a small paper width, The carriage can be further compacted by contracting the carriage. Further, for example, in the case of a thick recording material, the carriage is contracted in the rotational radius direction by an amount corresponding to the thickness, so that the recording material and the recording means are reduced. An image forming apparatus is provided which can maintain an appropriate distance from the recording medium and can perform good image recording even on recording materials having different thicknesses. According to the second aspect of the invention, in addition to the configuration of the first aspect, the recording material is fed in parallel with the carriage axis, so that the image forming apparatus can achieve the above-mentioned effects more efficiently. An apparatus is provided.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a configuration example of a main part of an image forming apparatus suitable for applying the present invention.

FIG. 2 is a schematic side view of the image forming apparatus of FIG.

FIG. 3 is a schematic perspective view of a recording unit (recording head) shown in FIG.

FIG. 4 is a partial longitudinal sectional view schematically showing a structure of an ink discharge section of the recording means of FIG. 3;

FIG. 5 is a schematic side view showing a main configuration of an embodiment of an image forming apparatus to which the present invention is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Carriage 2 Recording means (recording head) 3 Carriage rotation motor 4 Carriage shaft (guide shaft) 5 Carriage guide 6 Paper feed roller (conveyance roller) 7 Recording material 10 Follower gear (idle gear) 11 Tooth shape 51 Discharge port surface 52 Discharge port 55 Electrothermal converter

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B41J 19/20 B41J 2/01 B41J 2/235 B41J 2/24 B41J 19/00

Claims (4)

(57) [Claims] 1. A carriage on which a recording means is mounted at a leading end thereof is made expandable and contractible in a rotational radius direction, whereby a rotational radius of a moving path of the recording means is adjustable, and the carriage is rotated about a carriage axis. By letting
An image forming apparatus for performing recording on a recording material held on a circumference around the carriage shaft. 2. The image forming apparatus according to claim 1, wherein the recording material is fed in a direction parallel to a carriage axis. 3. The ink jet recording device according to claim 1, wherein the recording device is an ink jet recording device having an electrothermal converter for generating thermal energy for ink ejection.
Or the image forming apparatus of 2. 4. The image forming apparatus according to claim 3, wherein said recording means discharges the ink from the discharge port using film boiling generated in the ink by thermal energy applied by the electrothermal transducer. apparatus.