DE19642565A1 - Printed circuitry mounted on a cart with an integrated pen driver and power circuit - Google Patents

Description

This invention relates to ink jet printers and in particular on pen control systems for operating tin inkjet pens used in inkjet printers the.

An inkjet printer is a type of non-stop printer, characters and other images through the controllable Spraying ink drops from a printhead. On Conventional type of ink jet print head consists of an interchangeable cartridge or pen that comes from is exchangeably attached to a movable carriage. Of the Pen controllably injects liquid ink through multiple nozzles in the form of drops that spread over a small air move gap and land on a recording medium.

Ink droplets are characterized by localized heating ejected individual nozzles. A small heating element, typi usually in the form of a thermal resistor, is on arranged each nozzle. An electric current is through the Element directed to heat the same. The warmed up Ele ment vaporizes a very small volume of ink, which is caused by the Nozzle is ejected. The heating elements are common formed on a single silicon wafer chip, resulting in the on construction of the replaceable pen simple and the manufacture makes effortless.

A pin driver circuit is coupled to the heating elements pelt to the energy pulses for the controllable application of the To deliver ink drops. The pen driver speaks to you Character generator or other imaging circuit to excite selected nozzles to the desired image  to create. Energy pulses of an effective size to turn off ejecting a drop of ink from the pen to cause who referred to as the "launch pulse".

Previous inkjet printers had one on a carriage attached pin 30-50 nozzles. The pen driver was on a stationary printed circuit board (PCB; PCB = Printed circuit board) arranged next to the wagon path. On The flexible conductor bundle was between the PCB and the pin switched to move the carriage back and forth possible. The bundle of conductors consisted of a single lei ter that between the pen driver and a corresponding Nozzle heating element is switched, and conductors for power and ground signals. The pen driver transmitted firing pulses over the assigned ladder to the appropriate nozzles to activate the heating element.

The implementation was with a single conductor per nozzle for pens with a small number of nozzles (e.g. 30-50 Nozzles) effective. However, with the further development of the Pin the number of nozzles to a print of 300-600 dpi (dpi = dots per inch) of higher quality to enable. For example, some pens have the are commercially available today, about 300 nozzles. As the number of nozzles increased, the approach with egg nem conductor per nozzle from a control perspective with respect the coordination or the physical together build the several hundred conductors in a printer housing taking unwieldy.

To reduce the number of conductors, Tin developed Tenjet printer manufacturer pens with a low level Lo gik circuit that inte. in the resistance silicon wafer is free. Launch signals in the form of line and gap Ten addresses were connected to the pen via a smaller cable sent, the logic circuit using the addresses to choose the right nozzles. A combination of 16 Row and 14 column addresses could be used to  to drive a 300 nozzle pen. A small ribbon cable with only 30-40 conductor wires were used to get the addresses to transmit in parallel from the pen drivers to the pen whereby the cabling requirements to implement of a printer with a higher resolution is significantly reduced were. The HP Deskjet 850 and 1200 printers from the Hewlett-Packard Company are exemplary printers that sol have logic-based pins.

Logic-based pens are relatively inexpensive dig because the logic circuit in the same Si silicon chip is used, which is used to the To keep heating resistors. However, this implementation does not tion a disadvantage in that the control and Timing of the launch pulses by the pen driver the tape conductor is transferred to the movable pin, become increasingly difficult as the launch frequency increases and if the launch requirements have more precise control the launch pulse energy necessary. Today's printers keep pressing the envelope for a higher through set what higher launch rates and greater control over the energy pulses. Consequently, an additional one Control circuit included on the PCB to ensure that the control and timing of the launch pulse signals are exact.

To reduce the need for such tax precision some younger pens were introduced, one of which greater decoding intelligence on the pen IC (IC = Integra ted circuit) is placed. The print data becomes serial via a serial conductor from the statio pin driver nary PCB sent to the pin. A decoding circuit that contained in the pin decodes the serial bit stream into the corresponding column and row addresses, which then to shoot the selected nozzles of the selection logic scarf tion are fed.

Although this pen simplifies operation and helps  Delay and timing problems with the launcher to reduce nals, it is expensive to reduce the resulting Pen because the more sophisticated ICs on the Pen must be generated and implemented. These pens are, however, designed to be interchangeable and / or disposable to be other manufacturing goals of delivering an ef efficient way to restore used ink supplies fill up, fulfill.

The object of the present invention is a printed circuitry mounted on a carriage and to create a control system for an inkjet printer, which simplify and improve the operation of pens allow with a large number of nozzles without the fro increase the cost of replaceable pens.

A pen control system for an ink jet printer has a stationary printed circuit arrangement (PCA) that the ink jet printer frame is attached, and a ge printed carriage circuitry (PCA), which on the move Lichen car is attached to. A serial conductor ver binds the stationary PCA with the car PCA to serial Da ten, power and ground signals from the stationary PCA to transfer to the car PCA.

The carriage PCA has a pen driver that interconnects to receive the data signals from the stationary PCA The pen driver converts the data signals into nozzles election signals that are effective to cause a Pen ejects ink from selected nozzles. The nozzles election signals are via an electrical pin connector, which is an electrical coupling to the logic circuit on the Pen creates when the pen is installed in the cart is transferred to the pen.

The carriage PCA also has a power control circuit and a temperature control circuit. The surge of performance power circuit regulates power signals from the statio  nary PCA can be received at different voltage levels, which are used internally by the Cart PCA to control the Select and shoot pen nozzles. The temperature tax circuit offers localized control of the pen elements temperature.

By implementing the pen driver and lei Control circuit on the arranged on the car PCA, the launch pulses are generated locally and directly to that Transfer pin, as opposed to transferring over a long ladder. This design essentially eliminates that Problems with high-precision control of the launch pulses are assigned if they are from a stationary PCB too be transferred to a movable pin. Also offers the control system uses less expensive pens, thereby avoiding the manufacturing costs that the Production of highly integrated pens are assigned.

Preferred embodiments of the present invention are referred to below with reference to the attached drawing nations explained in more detail. Show it:

Fig. 1 is a schematic representation of a portion ei nes ink jet printer showing a control system accelerator as claimed aspect of this invention;

Fig. 2 is an illustration of the electrical circuitry from shot resistors used in an ink jet pen; and

Fig. 3 is a block diagram of the control system.

Fig. 1 shows a portion of a printing mechanism of an inkjet printer 10. The inkjet printer has a platen roller 12 , reciprocal movement assembly 14, and control system 16 . The platen roller 12 is a stationary or rotatable member that carries a recording medium during printing. The reciprocal movement assembly 14 has a carriage 20 which is slidably mounted on a solid, elongated Chen rod 22 to move bidirectionally over the platen roller 12 . The reciprocal movement assembly 14 also includes a drive subassembly (not shown), such as a pacer or DC motor, mechanically connected to the carriage that mechanically maneuvers the wa 20 along the bar 22 backwards and forwards.

The reciprocal movement assembly 14 has one or more ink jet printheads mounted on the carriage 20 . Two printheads 30 and 32 are shown for purposes of explanation. When attached to the carriage 20 , the printheads 30 and 32 are adjacent, but somewhat spaced from the platen roller 12 . A media feed mechanism (not shown), such as friction rollers or a traction device feed subassembly, is used to further move the print medium through the printer and between the platen 12 and printheads 30 , 32 . The carriage 20 guides the print heads 30 , 32 in a reciprocal movement over a printing surface. Each print run is called a "print ribbon".

According to a known type of construction, printheads 30 , 32 are implemented as replaceable, disposable pens that are removably attached to carriage 20 . Such pens have an ink supply contained therein, a nozzle pattern formed at the pen tip, and an integrated pen circuit (IC) with heating elements (ie resistors) and selection logic for these elements. With this configuration, each replaceable pen essentially forms an entire printhead. The terms "pen" and "printhead" as used herein are essentially interchangeable.

The first pen 30 is used for monochrome printing, for example black. It is a high resolution pen (e.g. 600 dpi) with an exemplary nozzle pattern consisting of 300 nozzles arranged in two vertical arrays of 150 nozzles, which are relative to each other by an offset equal to half a nozzle-to-nozzle distance is staggered. The second pen 32 is a multicolor pen that is capable of printing three different colors, for example cyan, magenta and yellow. The pin 32 has 64 nozzles for each color, making a total of 192 nozzles. The resolution of the color pen 32 is less than that of the black pen 30 , an exemplary resolution being 300 dpi.

Fig. 2 shows an electrical representation of the launch resistance in each pin IC 36th The launch resistors are arranged in an MxN matrix pattern. The columns of resistors (which are also called "basic patterns") use a common power line COL1, COL2,. . . COLN and a common ground line GND1, GND2,. . ., GNDN common. The rows of resistors (which are also called "addresses") use a common control or selection line ROW1, ROW2,. . ., ROWM. If an address line is selected (for example ROW1) and a row line is live (for example COL2), the nozzle resistance is fired at the intersection of the address line ROW1 and the column line COL2. The corresponding transistor conducts current through the resistance between the current-carrying row line and ground in order to increase the resistance to an effective temperature, which causes the evaporation and the ejection of an ink drop through the corresponding nozzle.

In the illustrated implementation with two pins 30 , 32 , the same address lines ROW1, ROW2,. . . ROWM shared by both pins (although one pin cannot use as many address lines as the other). Each pin has its own unique column of signal lines. During firing, an address line and possibly each column line becomes live to fire multiple nozzles at the same time.

The control system 16 has a stationary printed circuit arrangement (PCA) 40 , which is attached to a stationary device in front of the ink jet printer 10 , for example the frame or the housing. The control system 16 also includes a printed carriage circuitry (PCA) 42 attached to the carriage 20 and a conductor 44 that connects the stationary PCA 40 to the carriage PCA 42 . The stationary PCA 40 works as the primary logic or the motherboard and controls all aspects not related to the pen. The carriage PCA 42 controls all aspects related to the pen.

Generally, the stationary PCA 40 sends data, power, and ground signals to the car PCA 42 . The carriage PCA 42 has an input connector that connects to the conductor cable 44 to receive the data, power and ground signals from the stationary PCA 40 . Carriage PCA 42 also includes a pair of pin connectors in the form of conductive contacts that electrically couple to contact pads formed on pins 30 and 32 . The contact pads on the removable pins engage the contacts of the Wa gen PCA 42 when the pins in the carriage 20 are built.

Fig. 3 shows a block diagram of the control system 16. The stationary PCA 40 includes an I / O circuit 50 to handle I / O tasks to external devices, such as a host computer. The stationary PCA 40 also includes a carriage control circuit 52 for managing the carriage position and movement rate, a media control circuit 54 for controlling the media feed mechanism, and a control panel I / O circuit 56 for capturing user interface functions for the button panel and displaying the printer on. The stationary PCA 40 also includes a data / control formatter 58 that formats the data received from the host via the I / O circuit 50 into a serial bit stream that is routed to the carriage via the conductor 44 -PCA 42 is being sent.

A serial interface manages the communication between the stationary PCA 40 and the car PCA 42 . The serial interface is bidirectional and includes the serial conductor 44 . The serial interface transmits setting information, row / column selection data, power signals and a ground signal from the stationary PCA 40 to the car PCA 42 . The serial interface also transfers temperature data and status information from the car PCA 42 back to the stationary PCA 40 .

In one implementation, the bidirectional interface is implemented using five signals: DIn1 (data input 1 ), DIn2, Dout, DClk and DLoad. All signals with the exception of DOUT are entries in the stationary PCA 42 . The serial input data is shared and transmitted over two physical conductors in order to reduce the clock rate and the electromagnetic radiation. The signals are controlled to minimize interference radiation (EMI) while they are transmitted over a long flexible cable 44 (for example 40 cm) between the stationary PCA 40 and the car PCA 42 .

The first bit of the serial input word is an address bit that defines which data type is sent. A value ADIN = 0 means that print data will be sent, while a value ADIN = 1 means that setting data will be sent. The two different input words can be sent in any order. Data written by each of the input types is cached in the carriage PCA 42 until overwritten or deleted. The following Table 1 shows an example of a set of input bit assignments in the order of their transmission.

Table 1

serial input bit assignments

The carriage PCA 42 has a serial digital circuit 60 that receives the serial data stream from the cable 44, caches the data, and converts the serial stream into a parallel format for very fast use internally in the carriage PCA. The print data is sent when ADIN = 0 and includes the bits for the selection of columns and rows of launch resistors to be operated. The serial digital circuit 60 sends this print data to row and column drivers 62 , 64 which output the appropriate firing control signals to select and fire resistors in the pen firing matrices 36 , 37 to thereby cause ink to be ejected from the respective nozzles 38 To effect 39 . The row and column drivers 62 , 64 decode the five row selection bits to activate the corresponding rows in the firing matrixes 36 , 37 according to the following decoding table 2 .

Table 2

Row address decoding

In this implementation, the row addresses for rows 23 through 31 are undefined because the 300 pen nozzles can be adequately addressed using rows 1 through 22 and columns 1 through 14 . These additional addresses can be used for additional setup / control data, or can be reserved for future use if pens are made with more nozzles.

Two power signals of 18V and 5V are supplied to the car PCA 42 via the conductor 44 . The carriage PCA 42 has a voltage regulator circuit 66 that regulates the power signals to various voltage levels used in the carriage PCA to drive the pen 30 . The voltage regulator circuit 66 has four voltage regulator circuits:

• (1) a pin voltage regulator regulates the unregulated 18V signal to a voltage level Vpen of approximately 8V -12V. Vpen is used as a resistance firing source for the nozzles and is used on column lines COL1, COL2,. . ., COLN in the launching dies 36 , 37 too. The voltage Vpen is shared by both pins 30 , 32 since each pin is activated individually. The voltage Vpen is also programmable. The stationary PCA 40 sends a signal (e.g., 4 bits in the setting data format in Table 2) to the carriage PCA 42 to set the voltage level Vpen.
• (2) A line voltage regulator regulates the 18V signal to a voltage level Vrow of approximately 12V. Vrow is used to connect row lines ROW1, ROW2,. . . To select ROWM in the pin launching dies 36 , 37 .
• (3) A gate voltage regulator regulates the 18V power signal to a voltage level Vgate which is approximately equal to Vpen + 13V. Vgate is effective to provide the row and column pen drivers 62 , 64 with power.
• (4) A boost voltage regulator regulates the 18V Lei signal to a higher voltage level Vboost of approximately 36V.

Placing the voltage regulator circuit 66 on the carriage PCA 52 allows more precise control of the pen firing pulses. Unlike known systems, the firing pulses are no longer transmitted to the pen over a long cable. Instead, the various voltage levels and especially the sensitive voltage Vpen are generated in the car PCA 42 and briefly transmitted to the car. Problems that are associated with delays or a malfunction due to transmission via a cable, which makes precise control more difficult, are essentially eliminated in this design.

The pins 30 , 32 are designed to work optimally at a near constant temperature. The carriage PCA 42 is equipped with a temperature control circuit 70 to maintain the pins at their desired operating temperature. The temperature control circuit 70 has a pulse heating circuit 72 , a digital / analog converter 74 (D / A converter) and an analog / digital converter 76 (A / D). The temperature control circuit 70 sets a threshold temperature value while the D / A converter 74 generates the voltage applied to warm the pen to the target temperature.

The temperature control circuit 70 receives feedback information from each pen indicating the pen temperature. In one implementation, thermal sensing resistors are integrated into the pen and are used to measure the actual temperature of the pen. The thermal detection resistors show an increase in resistance when the pen heats up. This change in resistance appears as an increasing analog voltage signal, which is received as feedback information from the stylus and is converted to a digital signal by the A / D converter 76 . The digital value is measured against a threshold. When the actual pen temperature is below the desired minimum operating temperature, the pulse heating circuit 72 preheats the pen to the minimum operating temperature.

The carriage PCA 42 has further monitoring and control circuits 80 which handle a range of operating conditions. For example, circuits 80 track over / under voltage, row / column overcurrent, and other control conditions.

The carriage PCA 42 outputs certain data and status information to the stationary PCA 40 via the bidirectional serial interface. Like the input data, the output data from the carriage PCA 42 has an address bit ADOUT which indicates which data type is being transmitted. The value ADOUT = 0 indicates that status data is being sent, while the value ADOUT = 1 indicates that temperature data is being sent. Table 3 shows an example of the input bit set telling what type of data is being transferred. The value ADOUT = 0 indicates that status data is being sent, while the value ADOUT = 1 indicates that temperature data is being sent. Table 3 shows an example of input bit assignments set in the order of their transmission.

Table 3

Output bit assignments

Claims (10)

1. Printed carriage circuit arrangement ( 42 ) for attachment to a print head carriage ( 20 ) of an inkjet printer ( 10 ), the print head carriage ( 20 ) carrying one or more interchangeable pens ( 30 , 32 ), the printed carriage circuit arrangement having the following features having:
an input connector to make an electrical connection to a conductor ( 44 ) that transmits data, power and ground signals from one or more sources remote from the printhead carriage ( 20 );
a pin connector to facilitate electrical connection to a pin ( 30 , 32 ); and
a pen driver ( 62 , 64 ) coupled to receive data signals from the input connector and convert the data signals into nozzle selection signals which are effective to cause the pen to eject ink from the selected nozzles, the pen driver ( 62 , 64 ) outputs the nozzle selection signals to the pin via the pin connector. 2. The printed carriage circuitry of claim 1, further comprising a voltage regulator circuit ( 66 ) coupled to receive the power from the input connector and regulate the power to at least one voltage level. 3. Printed carriage circuit arrangement according to claim 1 or 2, further comprising the following features:
a pen voltage regulator circuit ( 66 ) to receive the power from the input connector and regulate the power to a voltage level applied to the pin connector for use as an activation source effective to cause ink to be ejected from the selected nozzles; is issued; and
wherein the pin voltage regulator circuit ( 66 ) is responsive to a control signal received from the input connector to adjust the voltage level. 4. Printed carriage circuitry according to any one of claims 1 to 3, further comprising a temperature control circuit ( 70 ) which is coupled to the pin connector to receive feedback from the pin ( 30 , 32 ), the pen temperature displays, and to control the pen temperature based on the feedback. 5. inkjet printer ( 10 ) having a printed carriage circuitry ( 42 ) according to claim 1. 6. Control system ( 16 ) for an inkjet printer ( 10 ), the inkjet printer having a movable carriage ( 20 ) which transports and positions at least one pen ( 30 , 32 ) over a printing surface, the control system having the following features:
stationary printed circuit board (PCA) ( 40 ) adapted for attachment to the ink jet printer outside of the carriage ( 20 );
printed carriage circuitry (PCA) ( 42 ) adapted for attachment to the movable carriage ( 20 );
a conductor (44) of the processing arrangement, the stationary printed scarf (40) to the printed carriage circuit arrangement (42) connects to data, power and Mas se signals between the stationary printed TIC assembly (40) and the printed Carriage circuit arrangement ( 42 ) to transmit;
wherein the printed carriage circuitry ( 42 ) includes a pen driver ( 62 , 64 ) coupled to receive the data signals over the conductor ( 44 ) from the stationary printed circuitry ( 40 ) and to convert the data signals to nozzle selection signals which are effective to cause the pen ( 30 , 32 ) to eject ink from selected nozzles; and
wherein the printed carriage PCA ( 42 ) includes an electrical pin connector to facilitate electrical connection to the pin ( 30 , 32 ) for transferring the nozzle selection signals from the pin driver ( 62 , 64 ) to the pin ( 30 , 32 ). The control system of claim 6, wherein the printed circuit board assembly ( 42 ) further includes a voltage regulator circuit ( 66 ) coupled to receive power from the stationary printed circuit board assembly ( 40 ) and the power at least to regulate a voltage level. 8. The control system of claim 6 or 7, wherein:
the carriage printed circuitry ( 42 ) further includes a pin voltage regulator circuit ( 66 ) to receive the power from the stationary printed circuit board ( 40 ) and to regulate the power to a voltage level that can be used on the pin connector as a voltage source effective to cause ink ejection from the selected nozzles is output; and
the stationary printed circuit board ( 40 ) sends data to the carriage printed circuit board ( 42 ) to adjust the voltage level generated by the pen voltage regulator circuit ( 66 ). The control system of any one of claims 6 to 8, wherein the carriage printed circuitry ( 42 ) further includes temperature control circuitry ( 70 ) coupled to the pin connector to receive feedback from the pin ( 30 , 32 ). which displays the pen temperature and to control the pen temperature based on the feedback. 10. inkjet printer ( 10 ) having a control system ( 16 ) according to any one of claims 6 to 9.