JP2670066B2 - Recording device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus, and more particularly to a recording apparatus using a heating element as an energy generating means for recording.

2. Description of the Related Art Conventionally, in a recording apparatus that uses a heating element as a recording energy generating unit corresponding to a pixel and applies a voltage to the recording element to generate heat, a voltage source is directly connected to the heating element. However, it is configured to perform only on / off according to the pixel signal. Further, the difference in the driving voltage value due to the variation in the size of each heating element is manually adjusted after the heating element is installed in the device.

[Problems to be Solved by the Invention] However, in the above-described conventional example, for example, when an abnormal high voltage is applied to the heating element due to a voltage source failure, it is detected that the voltage supply line is cut off. Since it was not configured, if such a situation occurs, the heating element may be burned out.

There is also a problem that it takes a lot of time and effort to adjust the driving voltage after setting the heating element in the device.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems by providing a means capable of appropriately controlling the driving of each heating element.

[Means for Solving the Problems] Therefore, according to the present invention, the power supply unit supplies electric power having a voltage value set based on the set value stored in the storage unit to the heating element to cause the heating element to generate heat. In a recording apparatus for recording by means of the above, voltage detection means for detecting the voltage value of the electric power supplied from the power supply section to the heating element, switch means for turning on / off the supply of electric power to the heating element, and voltage detection When the voltage value detected by the means is determined to be abnormal,
The switch means is caused to perform an operation of turning off the supply of electric power to the heating element, and the power supply unit switches the heating element from the power supply unit so that the voltage value detected by the voltage detection means becomes equal to the set value stored in the storage means. And a control means for controlling the voltage value of the supplied electric power.

[Operation] According to the present invention, when the control means determines that the voltage value detected by the voltage detection means is abnormal, the switch means performs the operation of turning off the power supply to the heating element. Even if an abnormal voltage is generated due to a circuit failure or the like, the power supply to the heating element can be cut to protect the heating element. Further, the control means controls the voltage value of the electric power supplied from the power supply unit to the heating element so that the voltage value detected by the voltage detecting means becomes equal to the set value stored in the storage means. It is possible to eliminate the complexity of adjusting the driving voltage when the device is incorporated into the.

Examples Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is an external view of a digital color copying machine to which a recording apparatus (printer unit) according to an embodiment of the present invention can be applied.

 The whole can be divided into two parts.

The upper part of FIG. 1 shows a color image scanner unit (hereinafter, abbreviated as scanner unit 1) that reads a document image and outputs digital color image data, and various types of digital color image data built in the scanner unit 1. It is configured by a controller unit 2 that performs image processing and has a processing function such as an interface with an external device.

The scanner unit 1 reads information from a three-dimensional object such as a book or the like placed below the document holder 11 or a sheet document, and also has a built-in mechanism for reading a large-size sheet document.

The operation unit 10 is connected to the controller unit 2 and is used to input various information as a copier. The controller unit 2 supports the operation of the scanner unit 1 and the printer unit 3 according to the input information.
In addition, when it is necessary to perform complicated editing processing, in place of the document retainer 11, an input means such as a digitizer is attached,
It is also possible to perform advanced editing processing by connecting this to the controller unit 2.

The lower part of FIG. 1 shows a printer unit 3 for recording a color digital image signal output from the controller unit 2 on recording paper. In the present embodiment, the printer unit 3
Japanese Patent Application Laid-Open No. 54-59936 discloses an ink jet recording type recording head using a recording head having an electrothermal converter (heating element) as an ejection energy generating element as recording energy generating means.・ It is in the form of a color inkjet printer.

The two parts described above are separable and, of course, can be installed remotely by extending the connecting cable.

FIG. 2 is a sectional view showing an example of the internal configuration of the digital color copying machine shown in FIG.

In the scanner unit 1, an exposure lamp 14, a lens 15, and an image sensor 16 (in this embodiment, a CCD) capable of reading a line image in full color,
An original image placed on the original platen glass 17, a projected image by the projector, or a sheet original image by the sheet feed mechanism 12 is read. Then, various types of image processing are performed by the scanner unit 1.
Then, the controller unit 3 performs the recording on the recording medium by the printer unit 3.

In FIG. 2, a recording medium such as paper or film (hereinafter referred to as recording paper) has a small fixed size (A4 to A3 in this embodiment).
The recording paper is supplied from a paper cassette 20 for storing recording paper (hereinafter referred to as cut paper) in the form of a cut sheet, or a roll paper 29 for performing recording of a large size (in this embodiment, A2 to A1 size). .

Further, by inserting the recording media one by one from the manual feed port 22 of FIG. 1 along the paper feed unit cover 21, it is possible to feed paper from the outside of the apparatus, that is, manually feed paper.

The pick-up roller 24 is a roller for feeding cut sheets one by one from the paper feed cassette 20, and the cut paper fed is conveyed to the first feed roller 26 by the cut paper feed roller 25. It

The roll paper 29 is sent out by a roll paper feed roller 30, cut into a fixed length by a cutter 31, and carried out to a first feed roller 26.

Similarly, the recording paper input from the manual feed port 22 is conveyed by the manual feed roller 32 to the first paper feed roller 26.

Pick-up roller 24, cut paper feed roller 25,
The roll paper feed roller 30, the first feed roller 26, and the manual feed roller 32 are driven by a paper feed motor (not shown) (for example, a DC servo motor can be used), and are turned on at any time by an electromagnetic clutch attached to each roller.・ Off control can be performed.

When the printing operation is started according to an instruction from the controller unit 2, the recording sheet selected and fed from any of the above-described paper feeding paths is transported to the first paper feeding roller 26. And
After removing a skew of the recording paper, a first paper feed roller 26 is turned on after a predetermined amount of paper loop is formed, and a second paper feed roller 27 is turned on.
To transport the recording paper.

Between the paper feed first roller 26 and the paper feed second roller 27, a predetermined amount of slack is applied to the recording paper for accurate paper feed operation between the paper feed roller 28 and the paper feed second roller 27. Make a buffer. The buffer amount detection sensor 33 is a sensor for detecting the buffer amount. By constantly forming such a buffer during the paper conveyance, it is possible to reduce the load on the paper feed roller 28 and the second paper feed roller 27, especially when a large-sized recording paper is conveyed, and to perform an accurate paper feed operation. It will be possible.

When printing with the recording head 37, the recording head 37
A scanning carriage 34 composed of the above-mentioned components scans a carriage rail 36 in a reciprocating manner by a scanning motor 35. In the forward scan, an image is printed on the recording paper, and in the backward scan, an operation of feeding the recording paper by a predetermined amount by the paper feed roller 28 is performed. At this time, the drive system is controlled by using a paper feed motor so that a predetermined buffer amount is always obtained while detecting the buffer amount by the buffer amount detection sensor 33.

The printed recording paper is discharged to the paper discharge tray 23 and the printing operation is completed.

Next, the periphery of the scanning carriage 34 will be described in detail with reference to FIG.

In FIG. 3, a paper feed motor 40 is a drive source for intermittently feeding the recording paper 38, drives the paper feed roller 28, and feeds the second paper feed roller 27 via the second paper feed roller clutch 43. To drive.

The scanning motor 35 is a drive source for causing the scanning carriage 34 to scan in the directions of arrows A and B via the scanning belt 42. In this embodiment, a pulse motor is used for the paper feed motor 40 and the scanning motor 35 in order to make the paper feed control accurate.

When the recording paper 38 reaches the second paper feed roller 27, the clutch
43 and the paper feed motor 40 are turned on to convey the recording paper to the paper feed roller 28 on the platen 39.

The recording paper 38 is detected by a paper detection sensor 44 provided on a platen, and the detection information is used for position control, jam control, and the like.

When the recording paper 38 reaches the paper feed roller 28, the clutch 43
Also, the paper feed motor 40 is turned off, and the suction operation is performed from the inside of the platen 39 by a suction motor (not shown) to print the recording paper 38.
On the platen 39.

Prior to the image recording operation on the recording paper 38, the scanning carriage 34 is moved to the position of the home position sensor 41,
Next, a forward scan is performed in the direction of arrow A, and a recording head provided with cyan (C), magenta (M), yellow (Y), and black (BK) inks corresponding to each color from a predetermined position. Discharge from 37 and image recording. When the image recording for a predetermined length is completed, the scanning carriage 34 is stopped, and conversely, the backward scanning is started in the direction of the arrow B and the scanning carriage 34 is returned to the position of the home position sensor 41. During the backward scanning, the paper is fed in the direction of arrow C by driving the paper feed roller 28 by the paper feed motor 40 by feeding the paper by the length recorded by the recording head 37.

In the present embodiment, the recording head 37 is a bubble jet type inkjet nozzle, and 256 nozzles are arranged in the conveying direction of the recording paper 38 orthogonal to the A and B directions, corresponding to the above four colors. I'm using four. Also,
Reference numeral 49 denotes a variable resistor provided for each recording head and used for setting an optimum drive voltage value, which will be described later.

The scanning carriage 34 is a home position sensor 41
When it stops at the home position detected by, the recording head 37 recovers. This is a process for performing a stable recording operation, and in order to prevent unevenness at the start of ejection, which is caused by the degree of change in the viscosity of the ink remaining in the nozzles of the recording head 37, the paper feeding time According to pre-programmed conditions such as temperature and ejection time, a cap device (not shown) located near the home position is moved to engage the recording head 37, and in this state, a pressurizing operation to the recording head 37, ink This is a process for performing an idle discharge operation and the like.

By repeating the operation described above, an image is recorded on the entire surface of the recording paper.

FIG. 4 shows a detailed configuration example of the recording head 37 used in the present embodiment, and each color has the same structure. Here, reference numeral 71 denotes an ink discharge port corresponding to one pixel, and recording is performed on a recording sheet by discharging ink from the ink discharge port. Reference numeral 52 denotes a heating element (heater) that is disposed in each nozzle 72 from the liquid chamber 74 to the ink discharge port 71 and heats ink. The heating element 52 is driven based on information of a corresponding recording pixel (hereinafter, this heater is referred to as a head). Described as a heater). The ink heated by the head heater 52 evaporates instantly,
The above bubbles are generated in the nozzle 72. This vapor pressure causes the ink in front of it to be ejected from the ink ejection port 71. The head heater 52 has a number corresponding to the number of nozzles (256 in this embodiment), and each of them is turned on / off independently according to pixel data. The ink is supplied to the liquid chamber 74 from the ink supply pipe 73.

Such a recording head 37 as used in this embodiment
In the case of, the image density may fluctuate depending on the magnitude of the applied voltage for heating the head heater 52 due to manufacturing variations of each head. If the applied voltage is too high, the head temperature may rise too high and the recording head 37 may be burned out.

Further, the recording head 37 has slightly different characteristics for each individual. Particularly, the optimum applied voltage is different, and if each recording head 37 is driven with the same voltage, a difference in recording density occurs between individuals, so the applied voltage must be adjusted for each recording head 37.

In the present embodiment, in particular, the correction of the variation between the individual recording heads 37 can be performed for each head, and when incorporating the recording head 37 into the apparatus, a means for making no adjustment is added. This is to prevent the recording head 37 from being burned out.

The main part of this example will be described in detail below with reference to FIGS.

FIG. 5 is a block diagram showing an example of the configuration of a drive circuit for the recording head 37 for one color. 52 is a head heater, 42
Is a drive transistor connected to each head heater. The drive transistor 42 is turned on / off by the pixel signal 43.
It is turned off and the energization of the head heater 52 is controlled. The head heaters 52 and their drive transistors 42 are actually provided for the number of nozzles (256 sets in this embodiment), but they are omitted in this figure.

Reference numeral 44 denotes a DC power supply (head power supply unit) that drives the group of head heaters 52, and the output voltage can be made variable so as to most appropriately drive one recording head 37.

FIG. 6 shows an example of the input / output characteristics of the head power supply unit 44,
The output voltage changes from 20V to 26V in proportion to the input voltage from 1V to 4V. The input of this head power supply unit 44 is D / A
An analog output of the converter 45 is connected, and a control unit 46 having a CPU in the form of a microprocessor and a ROM storing fixed data such as programs and the like outputs a digital value to a D / A.
It is configured so that a voltage of 1 V to 4 V can be taken out by inputting to the converter 45. Reference numeral 47 is an operational amplifier, which converts the output voltage value of the head power supply unit 44 into a level.
The output of the operational amplifier 47 is input to the A / D converter 53, converted into a digital value, and then input to the control unit 46.

Further, the control unit 46 can turn on / off the relay 48 via the output port P0, and can control whether to supply the output of the head power supply unit 44 to the head heater 52.

Reference numeral 49 is a variable resistor provided to store the optimum driving voltage which is different for each head.
One is provided for 37.

FIG. 7 shows an example of correspondence between the resistance value set in the variable resistor and the drive voltage value. And this variable resistor 49
The resistance value of can be read by the control unit 46 via the A / D converter 50. In response, the control unit 46 sets the drive voltage with reference to a table provided in, for example, a storage area of the ROM in correspondence with FIG. The resistance value is the drive head 37
Can be set manually at the time of manufacture.

Next, a control procedure by the control unit 46 according to the present example will be described.

FIG. 8 shows an example of the control procedure, and a program corresponding thereto can be stored in the ROM. Control unit 4
6 indicates the input port P when the printer unit 3 is powered on.
The voltage value is read from 3 (step S1). Since the resistance value of the resistor 51 and its terminal voltage (for example, + 5V) are known, the resistance value set in the variable resistor 49 can be known. Thus, the control unit 46 can determine the optimum voltage of the head 37 by referring to the table corresponding to FIG. 7 (step S3). At this time, the relay 48 is still off.

Subsequently, the control unit 46 refers to the conversion table (corresponding to FIG. 6) provided in the ROM so that the head power supply unit 44 outputs the head drive voltage, and the head power supply unit
The input voltage for 44 is determined and output from the output port P2 (step S5). Thereafter, the control unit 46 reads the actual output voltage value via the input port P1 (step S9). If there is an error, the error is corrected (step S11), and the output is performed again from the output port P2 (step S5). With the above operation, the head power supply voltage is optimally set, and the voltage setting sequence when the power supply of the apparatus is turned on is completed. Since the voltage is set each time the power is turned on in this way, it is possible to sufficiently cope with changes in the operating environment.

When the printer unit 3 is not recording (when a negative determination is made in step S13), the control unit 46 turns off the relay 48 and shuts off the power supply path to the head heater 52 (step S15). . Then, the output voltage of the head power supply unit 44 is constantly read from the port P1 and inspected (step S1
7) In the normal case, the power supply voltage is controlled via the port P2 so as to cancel only a minute voltage fluctuation when a small voltage fluctuation is detected.

When performing recording, for example, when the control unit 46 receives a recording command from the main control unit (controller 2) of the apparatus body, the relay 48 is turned on (step S21), and power is supplied to the head heater 52. Then, even during the driving of the head heater 52, the control unit 46 continues to monitor or control the output voltage of the head power supply unit 44 (Steps S23 and S25). If an abnormal voltage is detected, immediately turn off the relay 48 (step S2
7) The power supply to the head heater 52 is cut off to protect the recording head 37.

Further, the control unit 46 is not limited to the detection of the abnormal voltage, and if the output voltage value of the head power supply unit 44 corresponding to the output value from the output port P2 is not obtained from the input port P1, the value is abnormally high, or Steps S17 and S even if not low
23 is regarded as abnormal, and the relay 48 is not turned on. This is because there is a high possibility that a failure has occurred in any of the circuits shown in FIG.

As described above, by monitoring the voltage of the head power supply unit 44 and controlling its output, it is possible to prevent application of an overvoltage to the recording head 37 beforehand. Then, when an abnormality or a situation considered to be abnormal occurs, an abnormality process such as notifying the operator of the fact is performed by a display provided on the operation unit 10 or the like (step S29), and an appropriate process is prompted.

As described above, according to this example, the control unit 46 automatically detects and sets the optimum drive voltage according to the set value of the variable resistor 49 provided in the recording head 37. When a new recording head is installed in the device, no adjustment is required. This significantly simplifies the assembly or maintenance work of the device. In addition, since the appropriate overvoltage protection is performed for the set value set for each drive head 37, it is possible to detect abnormal voltage based on any set value for any printhead, and Detection does not vary.

In addition, in the above-described embodiments, the printer having the ink jet type recording head has been described, but the present invention can be applied to the recording apparatus having the thermal recording head with the same configuration, and the printer according to the thermal transfer type is used. It can also be applied as it is to a thermal paper type.

As means for storing the drive voltage of the recording head,
In this embodiment, the variable resistor is used and digitized through the A / D converter so that it can be read by the CPU in the form of a microprocessor, but it goes without saying that the storage means can be appropriately determined. For example, if high precision is not strictly required, about one or two small switches or jumper wires can be used instead of the variable resistors, and this eliminates the A / D converter. Cost can be reduced.

Further, at the upper side, the drive voltage is stored and determined for each printhead. However, if there is a variation among the heating elements constituting the printhead and it is necessary to compensate for this, one or more It is also easy to compensate the driving voltage in units of the heating element.

[Effects of the Invention] As described above, according to the present invention, the control means is
When the voltage value detected by the voltage detection means is determined to be abnormal, the switch means is caused to perform an operation of turning off the power supply to the heating element, and the voltage value detected by the voltage detection means is stored in the storage means. Since the voltage value of the electric power supplied from the power supply unit to the heating element is controlled so as to be equal to the set value, there is an advantage that no adjustment is required when the recording head is installed in the apparatus. This greatly simplifies the maintenance work, especially when assembling the apparatus or replacing the heating element or the recording head. In addition, since appropriate overvoltage protection can be performed on the individual heating elements or the heads, it is also effective in preventing their burning. Further, the control unit performs feedback control on the voltage value of the power supplied from the power supply unit to the heating element in addition to protection control against overvoltage of the heating element based on the voltage value of the power detected by the common voltage detection means. Therefore, there is an advantage that an increase in circuit scale can be suppressed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of the outer appearance of a digital color copying machine having an ink jet recording apparatus in a printer section as an embodiment of the recording apparatus of the present invention, and FIG. 2 is a diagram showing the digital color copying machine of FIG. FIG. 3 is a sectional view showing an internal configuration example, FIG. 3 is an explanatory diagram showing a detailed configuration example around the scanning carriage 34 of the printer section, FIG. 4 is a perspective view showing a detailed configuration example of the recording head in this example, and FIG. FIG. 6 is a block diagram showing an example of the configuration of a drive circuit provided corresponding to the recording head in this example, and FIG. 6 is a characteristic curve diagram showing an example of the input / output characteristics of the head power source unit in the configuration of FIG. FIG. 7 is a curve diagram showing an example of the correspondence between the resistance value set in the variable resistor and the drive voltage value in the configuration of FIG. 4, and FIG. 8 is an example of the control procedure of the head power supply with the configuration of FIG. It is a flowchart showing. 1 ... Scanner unit, 2 ... Controller unit, 3 ... Printer unit, 10 ... Scanning unit, 34 ... Carriage, 35 ... Scan motor, 37 ... Recording head, 44 ... Head power supply unit, 46 ... … Control unit, 49 …… Variable resistor, 52 …… Head heater.

Claims (3)

(57) [Claims] 1. A recording apparatus in which a power supply unit supplies electric power having a voltage value set based on a set value stored in a storage unit to a heating element and heats the heating element to perform recording. Voltage detection means for detecting a voltage value of electric power supplied from the power supply unit to the heating element, switch means for turning on / off the supply of electric power to the heating element, and voltage detected by the voltage detection means. When the value is determined to be abnormal, the switch means is caused to perform an operation of turning off the power supply to the heating element, and the voltage value detected by the voltage detection means is stored in the storage means. A control unit for controlling a voltage value of electric power supplied from the power supply unit to the heating element so as to be equal to the value. 2. The recording apparatus according to claim 1, wherein the control means changes a reference value for judging that the voltage value detected by the voltage detection means is abnormal according to the set value. 3. The recording apparatus according to claim 1, wherein the recording is performed by discharging ink by causing the heating element to generate heat.