JP2877542B2 - Image 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 a recording method using recording means.
An image recording apparatus that performs recording on a medium, particularly, a recording medium
The present invention relates to an image recording apparatus including a transport member that is an annular belt member that transports a body .

[0002]

2. Description of the Related Art In the non-impact recording method, the generation of noise during recording is extremely small so as to be negligible. Among them, the ink jet recording method capable of high-speed recording is an extremely effective recording method. An ink jet recording apparatus equipped with a recording head used in such a recording method transports a recording member such as paper or a resin sheet to an image forming area formed in an area facing the recording head by a transport unit, The image is formed on a recording member by discharging ink from a recording head according to a recording signal.

In a recording apparatus having such a configuration, as a means for transporting a recording member, there is a configuration in which the recording member is transported to an image forming area on a platen by driving a roller, and a configuration in which the recording member is transported to an image forming area by an endless belt.

[0004] The transport belt is hung on a plurality of rollers,
One or a plurality of the rollers are rotated by a driving source such as a motor, so that the rollers are driven to rotate by the driving force. Therefore, in order to drive the transport belt stably, it is necessary to sufficiently increase the frictional force so that no slip occurs between the transport belt and the drive roller. Therefore, the winding angle of the drive roller of the transport belt is set to be sufficiently large.

Conventionally, DC has been used to stabilize motor drive.
The use of a stepping motor in place of a motor, the stabilization of the tension in the case of an endless belt, and the like are performed to achieve good image recording.

[0006]

However, in multi-color printing by overlapping color printing, a small deviation causes a reduction in image quality, and this tendency is a serious problem particularly in ink jet recording in which landing accuracy is a problem. Become. Further, in a recording apparatus for further improving high-speed recording and image quality, it becomes a serious problem.

According to the present invention, as a result of newly examining minute conveyance unevenness which cannot be solved only by the conventional conveyance stabilizing means, a minute accuracy error of the recording medium conveyance member for the recording area used constantly is amplified. This is a technical issue that focuses on the cause of the problem.

[0008] By the way, even if it is observed that the thickness of the conveyor belt is made constant, the thickness of each of the plurality of manufactured conveyor belts may vary depending on the method including the steps of polishing the surface of the conveyor belt. In addition, it is very difficult to achieve a uniform thickness with high accuracy even within a single conveyor belt, and it is still not enough.

Therefore, in the configuration in which the transport belt is driven to rotate while the transport belt is wound around the drive roller, the transport belt is driven to rotate at a constant speed without eccentricity and uneven rotation of the drive roller. Also, since the transport belt itself has uneven thickness, the drive pitch diameter changes in the drive transmission section where the transport belt and the drive roller are in contact. That is, a ring having a predetermined thickness and elasticity
The endless transport belt, which is a belt member, is formed by two rollers.
Between the two rollers
Between the front side and back side of the straight part of the conveyor belt
Is almost nonexistent.
It can be said that the speeds on the front side and the back side are the same. However
However, the transport belt around the roller is
The front side is stretched while the back side is contracted
The speed of the front side of the conveyor belt and the back side of this part
Speed will be different. Therefore, transporting this part
The above-mentioned drive pitch diameter is used as a method for calculating the belt speed.
Is used. This drive pitch diameter is approximately
This corresponds to the radius of curvature of the middle part of the thickness of the bolt. Where
The thickness of the conveyor belt at the part wrapped around the roller changes
And the drive pitch diameter also change accordingly,
Similarly, the speed of the entire area passing through the roller
Become This change in speed is almost unchanged.
Changes in the speed of the conveyor belt in the straight section between
It is. In this way, since the endless transport belt is always subjected to this roller rotation, this change is directly brought to the recording area.
The change in the moving speed of the conveyor belt itself appears as a subtle difference in the moving speed of the surface of the conveyor belt. So
As a result, the recording member mounted on the conveyor belt with a difference on the front surface speed, it will occur unevenness in its conveying speed, resulting image as well as single variable power with respect to the transport direction of the recording member This causes a problem of color misregistration.

In the case where the thickness varies among the conveyor belts, the image formed between the recording apparatuses has a one-side magnification in the conventional level which does not take this into account. There was a possibility that the property may be reduced.

[0011] The present invention has been made to solve the problems mentioned above, the purpose without being affected by variations in the conveyance speed of the recording medium due to variations in the circumferential direction of the thickness of the conveying member An object of the present invention is to provide an image recording apparatus capable of realizing a good recorded image.

[0012]

In order to achieve the above-mentioned object, the present inventor has made intensive studies and found that the circumferential direction of the conveying member was reduced .
By detecting a change in thickness, of the conveying member due to the change
Turn the roller to compensate for fluctuations in the recording medium transport speed.
It has been found that good recording images can be obtained by controlling the recording timing of the rotation or the recording means .

[0013] The present invention has been made based on the above-mentioned findings, and is an image forming apparatus which performs recording on a recording medium using recording means.
In an image recording device, an annular shape having a predetermined thickness and elasticity
A conveying surface for conveying the recording medium.
A transfer member disposed on the outer surface, and the transfer member
The transfer member is supported by being stretched in the circumferential direction so as to be rotatable.
Two rollers, and the recording device disposed on the transport surface.
In order to be able to execute recording on the medium,
Holding means for holding the recording means in opposition,
Of the roller located on the downstream side in the recording medium conveying direction of the means.
It is provided at a position facing the peripheral surface, and on the peripheral surface of the roller.
Detecting means for detecting the thickness of a portion of the transport member,
Comparison between the detection value detected by the detection means and a reference value
Based on the difference between the two values,
Means for controlling the recording timing of the recording means
And the following.

[0014]

[0015]

According to the present invention, the recording medium of the image recording apparatus is carried.
Corrects fluctuations in the recording medium transport speed of the transport member due to variations in the thickness of the annular belt member that is the transport member to be transported
The image was magnified in the direction of conveyance of the recording medium.
To obtain a color image by successively superimposing multiple colors.
Image does not scale in the transport direction of the recording medium or
Does not occur.

[0016]

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings.

FIG. 1 is a schematic sectional view of a main part of an image recording apparatus for explaining a related art example of the present invention. The illustrated apparatus is an ink jet printer that discharges ink from a recording head and forms an image on a recording member arranged in an opposing area, and conveys the recording member by a conveyance belt 2 and the belt 2
Recording heads 1BK, 1Y, 1M, 1C
Is provided. Recording head 1BK, 1Y, 1M, 1
C operates according to a drive signal from a scanner unit (not shown) that reads a document and converts it into electricity. The recording paper as one of the recording members stored in a paper feeding device (not shown) arranged on the upstream side (the right side in the drawing) in the conveyance direction is transferred to the conveyance belt 2 one by one by the registration rollers 3 and 4 as necessary. Be loaded.

On the other hand, the transport belt 2 is endless, is hung between two rollers 5 and 6, and is rotated by a roller 6 driven to rotate in the direction of arrow X in the figure by a drive mechanism (not shown). In addition, a suction charger 7 is arranged close to the transport belt 2 so as to charge the surface of the transport belt 2. In this embodiment, the conveyor belt 2 is made of an elastic rubber material, and the upper surface thereof is electrostatically attracted to the recording paper by being charged. The recording paper is the recording head 1BK, 1Y, 1M, 1C
After passing through the recording paper, the recording paper is peeled off from the surface of the conveyor belt 2 by a curvature separation method using the waist of the recording paper, and sent out to a tray (not shown) by a discharge device or the like.

Here, the recording member includes an OHP sheet made of resin in addition to the recording paper.

A speed measuring device 8 is mounted near the recording heads 1BK, 1Y, 1M, and 1C to measure the moving speed of the conveyor belt and detect the moving speed of the conveyor belt by a control means for controlling the surface moving speed to be constant. Output the result.

FIG. 2 is a schematic diagram schematically showing the speed measuring device 8. The speed measuring device 8 includes a small wheel 9 provided so as to be able to contact the surface of the conveyor belt 2, and a structure in which a change in the speed of the surface movement of the conveyor belt 2 is electrically detected as a change in the rotation speed of the small wheel 9. It has become. Further, the speed measuring device 8 attaches reference marks 10 engraved at regular intervals to the surface of the conveyor belt 2 as shown in FIG. 3, and moves the marks 10 by the optical reader 11 shown in FIG. The change in speed may be optically detected.

By the way, the speed measuring device 8 may be provided at any position in the area facing the front of the conveyor belt, as long as the belt driving speed can be measured without hindering the conveyance of the recording member. For example, the recording head 1BK, 1
Y, 1M, and 1C can be provided on the upstream side or the downstream side in the recording member transport direction. In particular, when provided at a position close to the recording head on the upstream side in the transport direction, the time lag between the belt speed detection position and the recording position is reduced, and there is a merit that recording can be easily controlled.

The speed measuring device 8 is not limited to one, and a plurality of speed measuring devices 8 may be provided in the width direction of the conveyor belt 2.

FIG. 5 illustrates an embodiment of the present invention.
FIG. 2 is a schematic sectional view of a main part of the image recording apparatus of FIG . In a state in which the transport belt 2 is wound around a drive roller 5 connected to a drive motor (not shown), an end portion of the drive roller 5 longer than the width of the transport belt 2 and a surface of the transport belt 2 are respectively positioned on the surface. 12, 1 for detecting
3 is attached. The sensors 12 and 13 bring the actuator 14 into contact with the surface of the conveyor belt 2 and the surface of the drive roller 5, and measure the displacement to detect a change in the thickness of the conveyor belt 2. As shown in FIG. 6, a plurality of sensors 12 may be attached to the surface of the conveyor belt 2.
Further, a plurality of sensors 13 may be attached to one end or both ends of the drive roller 5. By providing a plurality of sensors in this way, more accurate thickness detection can be performed, and the effect of suppressing one-side magnification of an image is improved.

FIG. 7 is a block diagram of an embodiment of the present invention. 15 is a processor (CPU), 16 is a read-only memory (ROM), 17 is a readable and writable memory (RAM), 18 and 19 are input / output control devices (I / O),
19 is a detecting means, 21 is a control means.

First, the processor 15 executes a program stored in the ROM 16 by using the various detecting means 1 described above.
9 through the input / output controller 18
Store it in M17.

Next, the processor 15 performs a comparison operation between the reference value stored in the ROM 16 and the data stored in the RAM 17, and according to the degree of the difference between them, the number of rotations of the driving source of the transport belt or the recording head. The control unit 21 controls the ejection timing of the ink ejected from the printer through the input / output control device 20.

FIG. 8 is a flow chart according to one embodiment of the present invention. The detecting means detects the surface moving speed of the conveyor belt, and the control means controls the ink ejection timing of the recording head. Show the case. In this embodiment, since the speed is constantly detected by the surface moving speed detecting means, the conveyance of the recording member can be started at the same time as the driving of the conveyance belt is started. Since there is no data, the throughput can be improved. The recording start switch is turned on (step S1-
1) The drive motor is started (step S1-2), and the conveyance of the recording member is started (step S1-3). Here, the speed measuring device 8 detects the surface moving speed v of the transport belt, and the data is read into the RAM 17 (step S1-4).

Next, the CPU 15 performs a comparison operation between the reference values A and v previously stored in the ROM 16 (step S5).
1-5), if A = v, the ink ejection timing remains unchanged (step S1-6); if A> v, the ink ejection timing is delayed by an amount corresponding to the difference (step S1-6).
1-7) If A <v, the ink ejection timing is advanced by an amount corresponding to the difference (step S1-8).

After recording under the control of the CPU 15 (step S1-9), the recording member is conveyed to the conveyance end point, and the conveyance ends (step S1-1).
0). If recording is to be performed subsequently, the processes from step S1-3 to step S1-10 are repeated as many times as necessary, and then the drive motor stops (step S1-11) and the process ends.

Here, in one embodiment of the present invention, the inspection
The delivery means detects the thickness t of the conveyor belt 2, and
In the flowchart of FIG. 8 , step S1-4 is "reading the thickness t of the transport belt" and step S1-5.
Is “comparison operation of reference value B and t”.

Further, the control means controls the number of rotations of the drive motor.
Rotation control with increase or decrease of
1-6 is "the rotational speed of the drive motor is unchanged", step S1-7 is "increase the rotational speed of the drive motor", and step S1-8 is "decrease the rotational speed of the drive motor".
In this case, since the detection means is constantly operating, a high-quality image can be obtained without lowering the throughput.

FIG. 9 is a flow chart of another embodiment of the present invention, wherein the detecting means detects the surface moving speed of the conveying belt, and the control means controls the ink ejection timing of the recording head. Show the case. According to the present embodiment, the detection means may be operated only during the conveyance of one revolution of the conveyance belt after the recording start switch is turned ON.

When the switch for starting recording is turned on (step S2-1), the drive motor starts (step S2-).
2). Then, the speed measuring device 8 detects the surface moving speed v of the conveyor belt for one round from a reference point defined on the circumference of the conveyor belt, and the data is read into the RAM 17 (step S2-3).

Next, the recording members are stacked and transported in accordance with a reference point set on the circumference of the transport belt (step S2-4). At the same time, the CPU 15
Is compared with the reference speed A stored in the RAM 17 and the transport speed v of the transport belt for one round stored in the RAM 17 (step S2-5). When A = v, the ink ejection timing is unchanged (step S2). -6), when A> v, the ink ejection timing is delayed according to the difference amount (step S2-7), and when A <v, the ink ejection timing is advanced according to the difference amount (step S2). -8).

After the recording is performed under the control of the CPU 15 (step S2-9), the recording member is conveyed to the conveyance end point and the conveyance ends (step S2-1).
0). If recording is to be performed subsequently, the process from step S2-4 to step S2-10 is repeated as many times as necessary, and then the drive motor stops (step S2-11) and the process ends.

Here, in another embodiment of the present invention,
The detecting means detects the thickness t of the conveyor belt 2.
Ri, in the flowchart of FIG. 9, step S2-
3 is "reading of thickness t of transport belt", step S2
-5 is "comparison operation of reference value B and t".

Further, the control means controls the rotation speed of the drive motor.
Rotation control with increase or decrease of
2-6 is "the rotational speed of the drive motor is unchanged", step S2-7 is "increase the rotational speed of the drive motor", and step S2-8 is "decrease the rotational speed of the drive motor".
In this case, a high-quality image can be obtained only by operating the detecting means while the transport belt makes one rotation.

In the case where the variation in thickness within one conveyor belt or the change with time of the diameter of the drive roller 5 and the thickness of the conveyor belt 2 does not affect the quality of the recorded image, In this case, the operation of correcting the thickness variation of each transport belt may be performed. If this correction operation is performed once at the time of assembling the apparatus or installing the apparatus, there is no need to perform the correction operation thereafter. In such a case, the transport system shown in FIG. 1 or FIG. 5 is taken out of the apparatus, and the surface moving speed of the transport belt or the thickness of the transport belt is measured.
If stored in M16, the speed measuring device 8 or the sensor 12,
13 does not need to be installed in the device, and the size of the device can be reduced.

The present invention particularly provides an excellent effect in an ink jet recording head and a recording apparatus in which a flying droplet is formed by utilizing thermal energy among the ink jet recording methods and recording is performed.

The typical configuration and principle are described in, for example, 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 can be applied to both the so-called on-demand type and continuous type. In particular, in the case of the on-demand type, liquid (ink)
At least one drive signal corresponding to recorded information and providing a rapid temperature rise exceeding nucleate boiling is applied to the electrothermal transducer disposed corresponding to the sheet or the liquid path holding the liquid. As a result, heat energy is
This causes film boiling on the heat-acting surface of the recording head, and as a result, it is possible to form bubbles in the liquid (ink) in one-to-one correspondence with the drive signal. By discharging the liquid (ink) through the discharge opening by the growth and contraction of the bubble, at least one droplet is formed. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of a liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable.

As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. 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 configuration (a linear liquid flow path or a right-angled liquid flow path) of a discharge port, a liquid path, and an electrothermal converter as disclosed in the above-mentioned respective specifications. A configuration using U.S. Pat. No. 4,558,333 or U.S. Pat. No. 4,459,600, which discloses a configuration in which a heat acting portion is arranged in a bending region, is also included in the present invention.

In addition, JP-A-59-123670 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal converter for a plurality of electrothermal converters.
The present invention is also effective as a configuration based on JP-A-59-138461, which discloses a configuration in which an opening for absorbing the pressure wave is made to correspond to the discharge section.

Further, 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 is determined by combining a plurality of recording heads as disclosed in the above-mentioned specification. The present invention can exhibit the above-mentioned effects more effectively, though it may be either a configuration that satisfies the above requirements or a configuration as a single recording head that is formed integrally.

In addition, the print head is exchangeable with a print head of the chip type, which can be electrically connected to the main body of the apparatus and can supply ink from the main body of the apparatus, or is integrated with the print head itself. The present invention is also effective when a cartridge type recording head provided with an ink tank is used.

It is preferable to add recovery means for the print head, preliminary auxiliary means, and the like provided as components of the printing apparatus of the present invention since the effects of the present invention can be further stabilized. If you list these specifically,
Capping means, cleaning means, pressurizing or sucking means, a preheating means using an electrothermal transducer or another heating element or a combination thereof, and a preparatory means for performing a discharge different from printing on the printhead. Performing the ejection mode is also effective for performing stable printing.

Further, the recording mode of the 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 a plurality of recording heads. The present invention is also very effective for an apparatus provided with at least one of a multi-color color or a full-color color mixture.

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 at room temperature or is liquid, In general, in the ink jet method, the temperature of the ink itself is controlled 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, the temperature rise due to thermal energy can be positively prevented by using it as energy for changing the state of the ink from the solid state to the liquid state, or the ink can be left standing for the purpose of preventing evaporation of the ink. Either using ink that solidifies, or in any case, the ink is liquefied by applying heat energy according to the recording signal, and the ink is ejected as a liquid ink, or the ink that has already started to solidify when it reaches the recording medium. The use of an ink having a property of being liquefied for the first time by heat energy, such as described above, is also applicable to the present invention. In such a case, the ink is disclosed in JP-A-54-5684.
No. 7 or Japanese Patent Application Laid-Open No. 60-71260, while being held as a liquid or solid substance in a porous sheet concave portion or through hole so as to face the electrothermal converter. It is good also as a form. 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 to the above, the recording apparatus according to the present invention may be provided as an integrated or separate image output terminal of an information processing apparatus such as a word processor or a computer as described above. A copying apparatus combined with a reader or the like, or a facsimile apparatus having a transmission / reception function may be used.

[0053]

As described above, according to the present invention, the transport
Detects a change in the circumferential thickness of the feeding member and triggers the change.
To compensate for fluctuations in the recording medium conveyance speed of the conveyance member.
Roller rotation or recording timing of recording means
Can be controlled so that the image
In one direction, or color images with multiple colors
Even when an image is obtained, the image
Obtain good images without scaling or color shift
be able to.

[0054]

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a main part of an image recording apparatus for explaining a related art example of the present invention.

FIG. 2 is an explanatory diagram of a speed measuring device 8;

FIG. 3 is an explanatory diagram of a surface of a conveyance belt provided with an optical reading mark.

FIG. 4 is an explanatory view of another measuring device different from the device 8 of FIG. 2;

5 is a schematic sectional view of a main part of an image recording apparatus for explaining an embodiment of the present invention.

FIG. 6 is an explanatory view of mounting the sensors 12 and 13;

FIG. 7 is a block diagram of an embodiment of the present invention.

FIG. 8 is a flowchart of the embodiment of the present invention.

FIG. 9 is a flowchart of an embodiment of the present invention.

[Explanation of symbols]

 1BK Black recording head 1Y Yellow recording head 1M Magenta recording head 1C Cyan recording head 2 Conveyor belt 3 Registration roller 4 Registration roller 5 Roller 6 Roller 7 Suction charger 8 Transport speed measuring device 10 Mark 12 Sensor 13 Sensor

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI B41J 3/10 101H (72) Inventor Setsu Uchida 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Invention Toru Kobayashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masatoshi Katsui 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Mitomi Tatsuo Canon Inc. 3-30-2 Shimomaruko, Ota-ku, Tokyo (72) Inventor Yasuyuki Takanaka Canon Inc. 3-30-2 Shimomaruko, Ota-ku, Tokyo (56) References JP-A-2-2 80269 (JP, A) JP-A-56-89759 (JP, A) JP-A-61-242457 (JP, A) JP-A-62-108666 (JP, A) JP-A 64-72176 (JP, A) (58) Fields surveyed ( Int.Cl. ⁶ , DB name) B41J 2/01 B41J 2/51 B41J 11/42 B41J 19/76 H04N 1/23 101

Claims (9)

(57) [Claims] An image to be recorded on a recording medium using a recording means.
In the image recording apparatus, an annular belt member having a predetermined thickness and elasticity is used.
The transport surface that transports the recording medium on the outer surface.
A feeding member and the transport member are hung around , and the transport member is moved in the circumferential direction.
Two rollers, which are rotatably stretched and supported, and capable of performing recording on the recording medium disposed on the transport surface.
So that the recording means is opposed to the transport surface.
Holding means for holding, and said holding means positioned downstream of the holding means in the recording medium transport direction.
It is provided at a position facing the peripheral surface of the roller, and
Detection for detecting the thickness of the portion of the transport member on the peripheral surface
Means for comparing a detected value detected by the detecting means with a reference value
Based on the difference between the two values,
Means for controlling the recording timing of the recording means
The image recording apparatus characterized by having, when. 2. The control means according to claim 1 , wherein said detection value is a reference value.
If it is smaller, the roller
Increase the number of rotations of the
2. The method according to claim 1, further comprising:
Image recording device. 3. The control means according to claim 2 , wherein said detected value is a value equal to said reference value.
If greater, the roller
Reduce the number of rotations of the
2. The image according to claim 1, wherein the image is hastened.
Image recording device. 4. The recording means has a plurality of recording heads.
4. The method according to claim 1, wherein
Image recording device. 5. The control means according to claim 1 , wherein said control means is provided for one rotation of said transport member.
A storage unit for storing the detected value;
The rotation or rotation of the roller
Is characterized in that the recording timing of the recording means is corrected.
The image recording apparatus according to any one of claims 1 to 4, wherein
Place. 6. The recording means according to claim 1, wherein said recording means discharges ink.
Inkjet printing method for performing printing on the printing medium with
6. The method according to claim 1, wherein the step is a step.
The image recording apparatus as described in the above. 7. The recording apparatus according to claim 1 , wherein
Full liner with discharge ports over the maximum width of the medium
7. The image recording according to claim 6, wherein
apparatus. 8. The ink jet recording means according to claim 1, wherein
An electrothermal converter that generates thermal energy for discharge
The image according to claim 6, wherein the image is provided.
Image recording device. 9. The ink jet recording means according to claim 1, wherein
A drive to generate thermal energy that causes film boiling
9. The method according to claim 8, further comprising moving means.
Image recording device.