JPH04191074A - Image recording apparatus - Google Patents

Abstract

PURPOSE:To carry out feed/printing suitable for a size by judging the size of a sheet material on the basis of the number of times of the stepping feed of the sheet material calculated until the rear end of the sheet material is detected and changing both of or one of the feed quantity and recording region of the sheet material. CONSTITUTION:The detection point of a sensor arm 19 is set at the place separated by a distance (b) from fundamental feed quantity (a) on the upstream side in the feed direction of a sheet material 2. When the stepping number of times of the sheet material 2 is counted until the rear end of the sheet material 2 is detected by a transmission type photosensor 20, the kind of the sheet material 2 can be judged. When the kind of the sheet material is cleared, the sheet material 2 after the rear end thereof is detected by the sensor can be fed by feed quantity suitable for each sheet material. For example, in the case of a size A4, the feed possible quantity of the sheet material by upper and lower feed rollers 7, 8 after the rear end of the sheet material is detected by the sensor is 5mm and, in order not only to feed the sheet material 2 by 5mm but also to set a printing region to 5mm, by reducing the ink emitting region in a recording head 4, the overlap of printing can be prevented and printing can be carried out up to a region possible to feed by the upper and lower feed rollers 7, 8.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image recording apparatus that controls trailing edge printing on a recording material.

[Prior Art] Conventionally, an image recording apparatus that performs serial printing is configured as shown in FIG. Reference numeral 1 denotes an image recording apparatus main body, and a cassette 3 in which a plurality of sheet materials 2 are stacked is arranged at the bottom thereof. Further, on the left side of FIG. 2, a carriage 5 on which a recording head 4 is mounted is arranged, and a platen 6 is arranged below the recording head 4.

Here, the recording head 4 is an inkjet type head that records on the sheet material 2, has an ink chamber inside (not shown), and discharges ink from a plurality of nozzles according to an image signal. Although not shown, a carriage drive motor is connected to the carriage 5 via a timing belt, and the carriage 5 reciprocates along the guide shaft 5a by the carriage drive motor.

In the storage device, the paper feed roller 1 is activated by a feed signal.
When the sheet material 1 rotates, only the uppermost sheet of the sheet material 2 is separated and sent between paper feed guides 9 and 10.

Next, the sheet material 2 is guided by the paper feed guide 9.10, and is passed between the lower conveyance roller 7, which is rotated by a drive motor (not shown), and the upper conveyance roller 8, which is driven to rotate by this lower conveyance rough. Sent to and interrogated.

Next, the sheet material 2 is further guided through the platen 6 to the upper and lower tension rollers 12 and 13 by the transport force of the lower transport roller 7 and the upper transport roller 8, and the tip of the sheet material 2 is placed between the upper and lower tension rollers 12 and 13. It will stop once it gets caught.

Here, the lower tension roller 12 rotates in conjunction with the lower conveyance roller 7 and is driven at a slightly higher circumferential speed, and the clamping force for the sheet material 2 is made weaker than that of the upper and lower conveyance rollers 7.8. Therefore, an appropriate tension is applied to the sheet material 2 to prevent it from loosening.

In this state, the recording head 4 is moved by the carriage 5 from the front side to the rear side in FIG. 2, and discharges ink according to the image signal to record a constant width (recording width) on the sheet material 2.

Every time one line of recording is completed, the sheet material 2 is transferred by the lower conveyance roller 7 and the upper conveyance roller 8 by the same amount as the recording width.
7 to record the next line.

By repeating the above operations, recording is performed on the sheet material 2, and when the recording for 2-sheet materials is completed, the sheet material 2 is pulled from the upper and lower rollers 12 and 13 to the paper output tray 14.
is discharged to the top.

In addition, in order to properly connect the records of each line, the feeding accuracy of the sheet material 2 by the lower conveyance roller 7 must be high (
Specifically, high precision (of several tens of microns) is required.

For this reason, the outer diameter of the lower conveyance roller 7 is finished with high accuracy, and a pulse motor with high stopping accuracy is used as the drive device, and the rotation angle (rotation angle of the lower conveyance roller 7) is
is controlled by the number of pulses.

[Problems to be Solved by the Invention] However, after the sheet material 2 has passed through the upper and lower conveyance rollers 7.8, it is conveyed by the upper and lower tension rollers 12.13, but as described above, it is necessary to prevent sagging on the platen 6. Therefore, since the conveyance speed of the tension rollers 12 and 13 is set fast, the conveyance amount becomes large with the same amount of pulse motor rotation angle, and it is impossible to satisfy the high precision conveyance amount of several tens of microns. It was impossible. In other words, when the same pulse motor drives the conveyance roller and tension roller, if the pulse motor rotates the same amount without detecting that the sheet material has passed through the conveyance roller, the sheet material increases by the increased speed of the tension roller. It will be transported.

For example, if 8 mm conveyance is performed with 100 pulses and the speed increase ratio of the tension roller is 1%, then if the tension roller has 100 pulses of the motor, then 8 x 1.01 = 8.08
Ioffl feed exceeds 80 microns.

Therefore, the range in which the sheet material 2 can be recorded with high precision (the range in which it can be transported several tens of microns) is the range in which the sheet material 2 can be transported with high precision by the lower transport roller 7.

Here, let us consider the high-precision recordable range using the example shown in FIG.

First, assuming that the conveyance amount at the start of recording is 20 mm and the conveyance amount for each step is 8+nm, the relationship between the amount that can be conveyed by the upper and lower conveyance rollers in the final step and the sheet material length is shown in Table 1.
The value is shown in , and varies depending on the length of the sheet material. Therefore, in order to change the transport amount in the final step, a means for detecting the transportable amount is required. Here, a sensor arm 19 and a transmission type sensor 20 shown in FIG. 4 may be used to detect the trailing edge of the sheet material while it is being conveyed, but the conveying speed when conveying the sheet material 2 one step is the fifth. As shown in the figure, the rotation of the motor is in the acceleration-constant-velocity-deceleration pattern, so the sensor arm 19 is
It takes a certain amount of time to rotate to the position ', and at point A in Figure 5, the rear end of the sheet material 2 reaches the sensor arm 19.
Even if the sensor arm 19 is rotated, 19'
When the position is reached, it is time B, and there is an error by the amount indicated by the diagonal line in Figure 5, and the remaining trailing edge amount calculated based on the trailing edge detection output of the sheet material is much larger than the actual trailing edge remaining amount. It will be different. This relationship is shown in FIG. As described above, since the error caused by the detection means is large, the sheet cannot be conveyed using the final step conveyance amount shown in FIG.

[Means for Solving the Problems] The present invention includes a conveying means for a sheet material, a detection means for detecting a rear end of the sheet material, and a recording means for the sheet material,
In an image recording apparatus that records a constant width on the sheet material by the recording means and performs recording by sequentially repeating step conveyance of the sheet material of the constant width by the conveyance means, the detection means detects the trailing edge of the sheet material. Control that determines the size of the sheet material based on the number of step conveyances of the sheet material until the time when the sheet material is detected, and changes the conveyance amount of the sheet material and/or the recording area on the sheet material according to the size of the sheet material. It is equipped with the means.

[Function] According to the present invention, the length of the sheet material 2 is determined from the number of steps until the sensor detects the rear end of the sheet material 2, and the conveyance amount and printing area in the final step are controlled. There is something that was made.

In other words, although the paper size from the cassette is unknown, by counting the number of steps (for example, how many times 8!llIn feed was performed) until the trailing edge of the paper passes through the sensor arm, it is possible to determine the standard size (A4, 85, etc.). The size of the image can be determined, and conveyance and printing can be carried out appropriate to that size.

[Embodiment] FIG. 1 shows a first embodiment of the present invention. The basic configuration is the same as the conventional example. a is the basic conveyance amount of the sheet material in one step knob, and the detection point of the sensor arm 19 is set upstream in the conveyance direction of the sheet material 2 at a distance b from the basic conveyance amount a. .

Here, when the sheet material 2 is conveyed sequentially with the basic conveyance amount a, the lowest point occurs when the trailing edge of the sheet material is detected by the sensor arm 19 (i.e., it is determined whether the trailing edge of the paper has passed through the sensor arm 19). The amount of sheet material 2 still remains upstream of the upper and lower transport rollers 7.8 in the sheet material transport direction. The transport distance at the start of recording is 20 mm, the basic transport distance for 1 step is 8 mm (a), and the sensor arm position is 4 m.
If m(b), the number of steps until the transmissive photosensor 20 detects the trailing edge of the sheet material and the remaining amount of the sheet material 2 relative to the upper and lower transport rollers 7.8 at that time will be the values shown in Table 2. Here, the detection by the sensor may be performed by determining whether the sensor detects the trailing edge of the sheet material while the sheet material 2 is stopped after the conveyance of the sheet material 2 in each step is completed, as shown in the conventional example. Since the detection is not performed during transport, errors due to transport speed do not occur. If we pay attention to the number of steps until the sensor in FIG. 1B detects the trailing edge of the sheet material in this embodiment, the value differs depending on the size of each sheet material. Further, this value is a unique value for each sheet material if the conveyance amount at the start of recording, the basic conveyance amount in l steps, and the position of the sensor arm are fixed. In other words, the type of sheet material can be determined by counting the number of steps until the sensor detects the trailing edge of the sheet material. The remaining amount when the sensor detects the trailing edge of the sheet material is also a unique value for each sheet material, so if the type of sheet material is known, the amount of remaining material when the sensor detects the trailing edge of the sheet material is determined by the conveyance by the upper and lower rollers 7.8 after the sensor detects the sheet material. Since the possible amount, that is, the remaining amount when the sensor detects the trailing edge of the sheet material, is inevitably known, the sheet material 2 is conveyed by the appropriate amount for each sheet material after the sensor detects the trailing edge of the sheet material. It becomes possible to do so.

Considering A4 in Table 2 of this embodiment, the possible conveyance amount by the conveyance upper and lower rollers 7.8 after the sensor detects the trailing edge of the sheet material is 5 mm, which is a small value for the printing area of 8 mm. There is. In this case, by conveying the sheet material 2 by 5 mm and reducing the ink ejection area of the recording head 4 to make the print area 5rnrn, overlapping of prints can be prevented, and the area that can be conveyed by the upper and lower conveyance rollers 7.8 It is possible to print up to

In addition, the detection position of the sensor arm in this example is 12 mm (8 mm + 4 mm) with respect to the upper and lower transport rollers 7.8.
), but in the case of 86 in FIG. 1(B), the remaining amount when the sensor detects the trailing edge of the sheet material is close to 10 mm. For example, if the sensor arm detection position is 10 mm or less due to parts precision, etc., the number of steps until the sensor detects the trailing edge of the sheet material at B6 will be 20, and the remaining amount may be 2 mm. but,
From Table 2, it can be seen that the number of scans of 20 times corresponds to other sheet materials, and is closest to 19 times for B6. From this, even if the sensor takes 20 steps to detect the trailing edge of the sheet material, it is possible to determine that the sheet material size is B6, and as B6, 8 mm is conveyed 20 times, and the last 2 mm is conveyed. I can do it. Looking at other sizes in this way, if the number of steps taken by the sensor to detect the trailing edge of the sheet material varies by ±1, the number of steps will not interfere (become the same). That is, if the number of steps for each size such as B4.A4°B5.A5 is ±1, the same number will not come out.

In addition, in the case of B6, the remaining amount when the sensor is detected is 10 mm.
Therefore, after performing the basic conveyance of 8IllrIJ once, the remaining 2 mm is conveyed, and the first time, only the conveyance amount is controlled, and then the conveyance amount and printing area are controlled. That is, after the trailing edge is detected, there are cases where it is not necessary to reduce the conveyance amount and print area.

After the trailing edge of the sheet material 2 passes through the upper and lower conveyance rollers 7.8, the conveyance amount by the tension roller 12.13 and the printing area by the recording head 4 are controlled to control the printing area at the trailing edge of the sheet material. There are also ways to expand it. In this case, it is possible to convey the sheet material 2 after passing the upper and lower conveyance rollers 7.8, but the rear end of the sheet material 2 comes to the middle of the printing area of the recording head 4 due to the amount of conveyance. When printing, the platen 6 may be smeared with ink. In order to prevent this, control is required to reduce the print area of the recording head 4.

This will be explained below with reference to FIGS. 7A and 7C. When the above control is performed, the conveyance upper and lower rollers 7
．． After the rear end of the sheet material 2 passes through 8, the conveyance amount of the sheet material and the printing area on the sheet material will change. ). Printing area W = 8m
m, and the printing trailing edge position is β = 10 mrn, the number of steps until the sensor arm 19 detects the trailing edge of the sheet material 2 varies depending on the size of the sheet material 2, as in the first embodiment, and this number of steps It is possible to determine the size of the sheet material 2. As a result, the number of remaining steps in which 8 mm printing is possible and the amount in which 8 mm printing is impossible are determined.

After detecting the rear end of the sheet material 2 with the sensor, the remaining number of steps that can be printed by 8 mm is conveyed, and finally, the sheet material 2 is conveyed again by 8 mm.
mm, and change the printing area of the recording head 4 to 8f in Table 3.
By setting fIffl to the unprintable amount, it becomes possible to print up to the last end of the sheet material 2.

Further, in the case where a margin is provided at the rear end of the sheet material, the example shown in Table 4 is used. If the trailing edge margin is 5 mm, the remaining printable step of 8IIIn and the unprintable amount of 8 mm will change, but it is clear that they can be controlled in the same manner as described above.

(Others) In particular, the present invention is an inkjet recording method that includes a means (for example, an electrothermal converter, a laser beam, etc.) for generating thermal energy as energy used for ejecting ink, This provides excellent effects in recording heads and recording apparatuses that use energy to cause changes in the state of ink. This is because such a system can achieve higher recording density and higher definition.

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 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. The electrothermal converter that is
By applying a single drive signal that corresponds to the recorded information and causes a rapid temperature rise exceeding nucleate boiling, the electrothermal transducer generates thermal energy, causing film boiling on the heat-active surface of the recording head. This is effective because it causes bubbles in the liquid (ink) that correspond one-to-one to this drive signal.The growth and contraction of these bubbles causes the liquid (ink) to flow through the ejection opening. It is ejected to form a small droplet (at least one droplet).If this drive signal is in the form of a pulse, the growth and contraction of bubbles will occur immediately and appropriately.
Particularly responsive liquid (ink) ejection can be achieved,
More preferred. This pulse-shaped drive signal is described in U.S. Pat. Nos. 4,463,359 and 4,345,262.
Those described in the specification are suitable. Furthermore, if the conditions described in US Pat. No. 4,313,124 concerning the invention regarding the temperature increase rate of the heat acting surface are adopted, even more excellent recording can be performed.

The configuration of the recording head includes, in addition to the combination configuration of a discharge port, a liquid path, and an electrothermal converter (straight liquid flow path or right-angled liquid flow path) as disclosed in each of the above-mentioned specifications. The present invention also includes configurations using US Pat. No. 4,558,333 and US Pat. No. 4,459,600, which disclose a configuration in which the portion is arranged in a bent region. In addition, Japanese Patent Application Laid-Open No. 1989-5 discloses a configuration in which a common slit is used as a discharge part of a plurality of electrothermal converters.
No. 9-123670 and Japanese Patent Application Laid-Open No. 59/1989 which discloses a configuration compatible with an open discharge part that absorbs pressure waves of thermal energy.
The effects of the present invention are also effective even if the structure is based on the publication No.-138461. That is, regardless of the form of the recording head, according to the present invention, recording can be performed reliably and efficiently.

Furthermore, the present invention can be effectively applied to a full-line type recording head having a length corresponding to the maximum width of a recording medium that can be recorded by a recording apparatus.

Such a recording head may have either a configuration in which the length is satisfied by a combination of a plurality of recording heads, or a configuration as a single recording head formed integrally.

In addition, even with the serial type shown above, the recording head is fixed to the device body, or by being attached to the device body, electrical connection to the device body and ink supply from the device body are possible. The present invention is also effective when using a replaceable chip type recording head or a cartridge type recording head in which an ink tank is integrally provided in the recording head itself.

Further, it is preferable to add recovery means for the recording head, preliminary auxiliary means, etc., which are provided as a configuration of the recording apparatus, to the present invention because the effects of the present invention can be further stabilized. Specifically, these include a capping means for the recording head, a cleaning means, a pressure or suction means, a preheating means 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 recording in order to perform stable printing.

In addition, regarding the type and number of recording heads installed, for example, in addition to one type that corresponds to single-color ink, there is also a plurality of recording heads that correspond to multiple inks with different recording colors and densities. It may be something that can be done. That is, for example, the recording mode of the recording apparatus is not limited to a recording mode for only a mainstream color such as black, but may also be a recording mode in which the recording head is configured integrally or in a combination of multiple colors, The present invention is also extremely effective for devices equipped with at least one full color by color mixing.

Additionally, in the embodiments of the present invention described above,
Although ink is described as a liquid, it is an ink that solidifies at room temperature or below, but softens or liquefies at room temperature, or in an inkjet method, the ink itself is
Generally, the temperature is adjusted within the range of 0°C or more and 70°C or less so that the viscosity of the ink is within the stable ejection range, so even if the ink is in a liquid state when the recording signal is applied. Bye. In addition, the temperature increase caused by thermal energy can be actively prevented by using the energy to change the state of the ink from a solid state to a liquid state, or ink that solidifies when left standing is used to prevent ink evaporation. In any case, the ink is liquefied by applying thermal energy in accordance with the recording signal, and the liquid ink is ejected, or the ink has already begun to solidify by the time it reaches the recording medium. The present invention is also applicable when using ink that is liquefied only by energy. The ink used in this case is
Publication No. 4-56847 or JP-A-60-71260
As described in the above publication, the porous sheet may be held in a liquid or solid state in the recesses or through-holes of the porous sheet, facing the electrothermal converter. In the present invention, the most effective method for each of the above-mentioned inks is to implement the above-mentioned film boiling method.

In addition, in addition to being used as an image output terminal for information processing equipment such as a computer, the inkjet recording apparatus of the present invention may also take the form of a copying machine combined with a league, etc., or a facsimile machine having a transmission/reception function. It may also be something.

[Effects of the Invention] As explained above, a sensor is provided to detect the rear end of the sheet material, and the sensor detects the rear end of the sheet material (for example, when the sensor arm is in the state 19' shown in FIG. The size of the sheet material can be determined by counting the number of conveyance steps of the sheet material until the state of
It has become possible to reduce the amount of blank space at the rear end of the sheet material 2.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a first embodiment of the present invention, Fig. 2 is a schematic diagram of an image recording device of the present invention and a conventional example, Fig. 3 is a diagram showing a conventional example, and Fig. 4 is a diagram showing a conventional example. 5 is a diagram showing the conveyance speed of the sheet material, FIG. 6 is a diagram showing the theoretical value and measured value of the sensor, and FIG. 7 is a diagram showing the second embodiment of the present invention. l... Image recording apparatus body, 2... Sheet material, 4... Recording head, 7.8... Conveyance upper and lower rollers, 12, 13... Tension upper and lower rollers, 19 ...Sensor arm, 20...Transmission type sensor. (A) Figure 1 (B) Figure 3 Time Figure 5 Figure 6

Claims (1)

[Scope of Claims] 1) A means for conveying a sheet material, a detection means for detecting the trailing edge of the sheet material, and a recording means for the sheet material, and the recording means allows the sheet material to be recorded by a certain width. In an image recording apparatus that performs recording by sequentially repeating step conveyance of a sheet material of a constant width by the conveyance means, the step conveyance of the sheet material until the rear end of the sheet material is detected by the detection means. Image recording characterized by comprising a control means that determines the size of the sheet material based on the number of times and changes the conveyance amount of the sheet material and/or the recording area on the sheet material in accordance with the size of the sheet material. Device.