HARDWARE > PRINTERS > EPSON

EPSON760.TXT

Description: Frequently Asked Questions

Product: EPSON Stylus COLOR 760

FAQ Version: 1.1

Date: November 19, 1999

Author: RM

Document Standard Version: 3.1

This document is written and maintained by representatives of Epson

America, Inc. Although this is official information, the

specifications and support information may be changed without

notice. Any requests for additions or modifications to the FAQ

should be sent to EPSON at the Internet e-mail address:

faqinfo@eA:epson.com. This e-mail address is for correcting FAQ

file information only. If you need additional technical information

or support, please use any source from the list below.

Automated Support (FaxAdvice and/or SoundAdvice): (800) 922-8911

(24 hours a day, 7 days a week)

EPSON Connection Technical Support (U.S.): (562) 276-7542

(6 AM-6 PM Monday-Friday Pacific Time)

EPSON Connection Technical Support (Canada): (905) 709-2567

(6 AM-6 PM Monday-Friday Pacific Time)

Internet: http://www.epson.com

To order drivers: Driver fulfillment support line (562) 276-4367

(6 AM-6 PM Monday-Friday Pacific Time)

To purchase accessories: EPSON Accessories (800) 873-7766

(6AM-6 PM Monday-Friday Pacific Time)

Product Controls: Stylus Color 760

Power Button - Turns power on and off.

It is important to use the printer's Power button rather than a

power strip to control power to the printer.

Cleaning Button - Make sure the printer is turned on but not

printing, and the black and color ink out lights are off. Press and

hold the cleaning button for three seconds. Cleaning takes about 30

seconds, during which the printer makes some noise and the power light

flashes. When the cleaning cycle is complete, the power light will

stop flashing.

Load/Eject Button - Loads or ejects paper in the printer.

Printer Test - You can run a printer check to determine whether a

problem comes from the printer itself or some other source. Follow

these steps to run the printer check:

1. Make sure both the printer and computer are turned off.

2. Disconnect the interface cable from the printer.

3. Make sure paper is loaded in the printer.

4. Hold down the load/eject button, then press and release the power

button. Continue holding down the load/eject button until the power

light starts to flash, then release it. The printer prints one page

showing its ROM version number, ink counter, and a nozzle check

pattern. If the pattern has gaps in its dots, you need to clean the

print head.

5. To end the check, turn off the printer after it prints the check

page. Then reconnect the interface cable and turn on your printer and

computer. If the check page prints, the problem probably lies in your

software settings, the interface cable, or your computer.

If the check page doesn't print, you may have a problem with your

printer.

Questions and Answers

Q: Is the printer Year 2000 ready?

A: Yes, the printer is Year 2000 ready.

Q: How does Micro Piezo technology compare to thermal technology?

A: Epson's Micro Piezo (M.P.) technology outperforms thermal

technologies in all areas: pressure method - electromechanical

(M.P.) vs. boiling (thermal), print head life - permanent (M.P.) vs.

disposable (thermal), ink flexibility range - wide (M.P.) vs.

limited (thermal), potential for improvement - significant (M.P.)

vs. limited (thermal). Micro Piezo technology provides the highest

resolution, smallest dot size, precise dot volume, precise dot

shape, precise dot placement, and fastest head firing times. Thermal

technology creates satellites and misting which Micro Piezo

technology eliminates.

Q: What is the proper way to turn off the printer?

A: Make sure that whenever you turn off the printer, you are always

using the printer's power button. This will assure that the print

head is properly parked in the correct position. Never use an

external switch, such as a power strip, surge protector, or power

protector, to turn off the printer. It can be harmful to your

printer if you turn the printer off using an external switch.

Q: Do the Stylus COLOR 760 and Stylus COLOR 860 use the same ink

cartridges?

A: Yes, these printers use the same black (part number S020189) and

color (part number S020191) ink cartridge. Only cartridges with

these part numbers are compatible.

Q: Can the Epson ink cartridges be refilled or can 3rd party ink

cartridges be used without voiding the warranty?

A: EPSON does not recommend refilling or using 3rd party ink

cartridges. Using these products will not void their product's

original warranty, however, if these 3rd party products cause a

failure, the repair of that failure will not be covered under

warranty.

Q: How can I obtain driver disks?

A: The printer driver software is on the CD-ROM bundled with the

printer. The files are also available from alternate sources. The

driver is available for download from the EPSON Internet web site.

You may also contact the EPSON Connection Group to request a printer

driver. A shipping and handling charge may be applied to drivers

sent by mail.

Q: Can I use the cleaning sheets that I may find included with any

special media I purchase?

A: No. These sheets can jam and damage the printer.

Q: Can I use sheet labels with this printer?

A: Yes, EPSON makes Photo Quality Self Adhesive Sheets. To avoid

paper jams, only load one Photo Quality Self Adhesive Sheet at a

time. Also, set the Media Type in the printer driver to the "Photo

Quality Ink Jet Paper" setting.

Q: What is the correct way to load transparency paper?

A: Before loading the transparency, place the included support sheet

or a sheet of plain paper beneath the transparency (or beneath the

stack of transparencies if you are loading more than one). You can

load up to 10 transparencies at a time, but if you have more than

one transparency loaded, the minimum top margin you can use is 1.2

inches. Also, you may get better results by loading one sheet at a

time. Insert the transparency sheet making sure that the notch is

at the top right side of the sheet. Remember to choose the correct

Media Type setting in the printer driver software. Please refer to

your User's Guide for detailed information.

Q: What are the system requirements for using this printer?

A: PC Compatible

- An IBM (r) compatible PC with at least a 486/66 MHz

(for Windows (r) 98) or 486/25 MHz (for Windows 95 or Windows NT

(r) 4.0) processor (Pentium (r) processor recommended). USB requires

Windows 98

- VGA, Super VGA, or better display adapter and monitor

- Windows 95, Windows 98, or Windows NT 4.0

- At least 16MB of RAM (32MB for Windows 95 or 98, or 64MB for

Windows NT 4.0 recommended)

- At least 50MB of free hard disk space (100MB recommended)

- Double-speed (2x) CD-ROM drive (quad-speed [4x] or faster

recommended) for installing the printer software

- A high-speed, bidirectional, IEEE-1284 compliant parallel cable (6

to 10 feet long); the cable must have a D-SUB, 25-pin, male

connector for your computer and a 36-pin, Centronics (r) compatible

connector for the printer

- For USB connection: a computer running Windows 98 with a Windows

98 compliant USB port and a shielded USB "AB" cable from Series A

(computer) to Series B (printer), up to 6.5 ft. (2 meters) long.

A: An Apple (r) iMac (tm) series or Power Macintosh (r) G3 with USB

port

For iMac: Mac (r) OS 8.1 or later

For Power Macintosh G3: Mac OS 8.5.1 or later

If your iMac is running OS 8.1, you'll need to update your

Mac OS ROM before installing your printer software. Download

and install iMac Update 1.0 or later from Apple at

http://swupdates.info.apple.com. Contact Apple if you have problems

installing the update. If your iMac is running OS 8.5 or 8.5.1,

do not install iMac Update 1.0. Instead, Apple recommends that you

download and install iMac Update 1.1. To find out which operating

system your iMac is running, select About This Computer from the

Apple menu.

- At least 16MB of available RAM (32MB recommended)

- At least 50MB of free hard disk space (100MB recommended)

- VGA, Super VGA, or better display adapter and monitor

- Double-speed (2x) CD-ROM drive (quad-speed [4x] or faster

recommended) for installing the printer software

- A shielded USB "AB" cable from Series A (computer) to Series B

(printer), up to 6.5 ft. (2 meters) long.

Q: What do I do if I see a "New Hardware Found" window before I

install my printer software with a parallel connection?

A: Cancel the window by clicking on "Do not install a driver" and

then "OK". You cannot install the printer driver software by using

the "New Hardware Found" window.

Q: How do I install the driver from the EPSON Stylus COLOR 760

CD-ROM in Windows 95/98/NT 4.0 with a parallel connection?

A: Insert the EPSON printer software CD in your CD-ROM Drive

- Click "Start", Select "Run", and type "D:\EPSON.exe"

(Where D is your CD-ROM drive letter)

- Then click "OK"

- You will see the License Agreement window. Read the agreement and

click "Agree"

- Select Install Printer Driver from the Main Menu screen.

- Click "OK" on the EPSON Printer Utility Setup screen.

- Click "OK when setup is complete.

- Return to the main menu screen to install your Creative Software.

Q: How do I remove the printer driver from Windows 95/98/NT 4.0?

A: Click on the Windows 95/98 "Start" button, select "Settings",

select "Control Panel", and then double-click on "Add/Remove

Programs". Double-click on "EPSON Printer Software", select the

Stylus Color 760/860 printer and remove it. For Windows 98 USB

connection remove the EPSON USB Printer also.

Q: How do I install a printer driver from the EPSON Stylus COLOR 760

CD-ROM on a Macintosh with USB connection?

A: - USB "AB" cable is required.

- Turn off your printer.

- Turn on your computer and wait until you see the Macintosh desktop

icons.

- Turn on your printer.

- Insert your printer software CD into your CD-ROM drive

- Double-click on the EPSON Icon

- Click "Agree" to the license agreement.

- Click 'Continue' at the first screen.

- At the installer screen, click 'Install' and follow the on-screen

instructions to install your printer software, select your default

paper size, click "OK" and restart your system.

- You need to select your printer in the Chooser Setup.

- Open the Apple menu and click 'Chooser'.

- Click the Stylus Color 760 icon, "USB Port1 or 2" should appear as

your printer port.

- Turn on background printing, if you want to use it. Then close the

chooser.

Q: How do I trash the printer driver from my Macintosh?

A: Trash the "SC 760", "EPSON Monitor3", and "EPSON Folder"

extensions from your "Extensions" folder (the "Extensions" folder is

located in your "System Folder" folder in your hard drive). Then,

restart your Macintosh. If you have printer drivers of other EPSON

printers installed on your system, you may need to reinstall them

after removing the Stylus COLOR 760 driver.

Q: How do I install my ink cartridge for the first time?

A: First Ink Cartridge Installation (takes approximately two

minutes).

Turn the printer on. The power light will flash, the ink out lights

will come on, and the ink cartridge holders will automatically move

left to the installation position. Remove the yellow tape seals

from the black and color ink cartridges. Do not remove the blue

label from the top of either ink cartridge. The ink in a cartridge

missing the blue label will be exposed to air and will thicken such

that print head clogging and possible print head failure can occur.

If the blue label has been removed from an ink cartridge, the

cartridge will not function correctly and it will need to be

replaced. More importantly, to avoid potential damage to the

printer, do not install a cartridge from which the blue label has

been removed. Install the cartridges into the printer. Make sure

the labels on the ink cartridges are facing up and that the arrows

on the labels point toward the back of the printer. The black ink

cartridge goes on the left and the color ink cartridge goes on the

right. Once the ink cartridges have been inserted into their

holders, push down the ink cartridge clamps until they lock in

place, and then press the cleaning button to begin charging the ink

delivery system. Charging can take up to two minutes and is

complete when the power light stops flashing.

With the new IEEE-1284.4, D4 mode parallel port technology and the

Status Monitor 3, you can connect the printer to the PC and the

Status Monitor 3 will walk you through the initial cartridge

installation. This only works for the first cartridge installation.

Caution:

If the blue label has been removed from the ink cartridge, do not

install the cartridge. If you have already installed it, even if

the printer is printing correctly, change the cartridge immediately.

If you have already installed the cartridge and now the nozzle

check will not print completely even after running a few cleaning

cycles, the printer may need service and you should contact Epson

technical support for assistance.

Q: How do I replace an ink cartridge when an ink low or out

condition occurs?

A: Install Replacement Ink Cartridge when an ink low or out

condition occurs - Remove the yellow tape seal from the ink

cartridge. Do not remove the blue label from the top of the ink

cartridge. The ink in a cartridge missing the blue label will be

exposed to air and will thicken such that print head clogging and

possible print head failure can occur. Power off and on the printer.

Raise the printer cover, then press down the paper feed load/eject

button until the print heads move to the left. Install the ink

cartridge and press the paper feed button to begin charging the ink

delivery system. Charging takes about two minutes and is complete

when the power light stops flashing.

Caution:

If the blue label has been removed from the ink cartridge, do not

install the cartridge. If you have already installed it, even if

the printer is printing correctly, change the cartridge immediately.

If you have already installed the cartridge and now the nozzle

check will not print completely even after running a few cleaning

cycles, the printer may need service and you should contact Epson

technical support for assistance.

Q: I installed new ink cartridges and the printer is now doing

continuous cleaning cycles. Is there something wrong with my

printer?

A: When an ink cartridge is installed into the printer, it will take

approximately 2 minutes to charge the ink system and initialize the

printer. While the ink is charging the power light will flash.

Never turn off the printer while the power light is flashing (unless

the power light is flashing AND the printer has not moved or made

noise for over 5 minutes). This initialization is a normal and

necessary process.

Q: The colors of my image on my monitor do not match the output from

my printer. What is wrong?

A: First you must have an understanding of how color is produced.

A monitor displays color by transmitting Red, Green and Blue (RGB)

light into your eyes. A printer uses existing light to reflect

Cyan, Magenta, Yellow and blacK (CYMK) light into your eyes.

It is virtually impossible to have these two different color types

(transmissive and reflective) to match perfectly. Also, due to its

transmissive nature, the monitor is able to display a much wider

range of colors than a reflective product, such as a piece of paper

with ink on it.

Secondly, most monitors are not calibrated for correct color display

out of the box, they have to be calibrated to produce accurate

colors. Adobe PhotoShop includes a basic monitor calibrator to do

this; it is the Adobe Gamma utility. This utility is contained in

the Control Panel in Windows and on the Macintosh. Some of the

higher-end monitor calibrators use a suction cup device that sticks

on the monitor and reads a range of colors displayed on the monitor.

These hardware/software combination devices create much more

accurate color profiles than the strictly software solutions.

Also, what type of color matching system (CMS) are you using when

printing your image? The color matching system can greatly affect

the output color of your image. For information on how to use the

various color management system available, please check the CMS user

documentation or the website of the manufacturer.

To ensure that the images your Epson Color printer produces are as

close as possible to the images displayed on your monitor you should

do the following:

Calibrate your monitor

Experiment with various Color Management Systems

Try using the ICM (Windows 95 or 98) or ColorSync (Macintosh)

setting

Q: The quality of my printed output is unacceptable. What can I do

to improve this?

A: First verify that you are using the correct printer driver for

your printer model. Make sure that the printer's paper thickness

lever is set to 0 for regular paper and + for envelopes or thicker

media: If MicroWeave is off, turn this feature on in advanced

settings. If High Speed is on, turn it off. Make sure the Media

Type setting matches the paper or media loaded. Also, the

Halftoning and Color Adjustment Mode options may be set incorrectly

for your document type. Let the printer driver automatically select

the settings for the best quality.

Secondly verify that the printable side of the paper is face up, and

check the type of paper being used. EPSON brand paper, which is

specifically designed for the Stylus ink jet series of printers,

delivers the best-printed output. If your output is faint, check the

printer driver to make sure you have selected a print resolution

other than Economy. The resolution of your image may also be set too

low. Increase the image resolution using your image-editing

software, or decrease the size of the image.

Also, try testing the printer to another computer. This will

eliminate the possibility of a defective printer cable, parallel

port, or software issue. If you're still experiencing a problem,

try replacing the ink cartridge and make sure you are using a

genuine EPSON ink cartridge. If the blue label has been removed from

the ink cartridge, do not install the cartridge.

Caution:

If the blue label has been removed from the ink cartridge, do not

install the cartridge. If you have already installed it and the

printer is printing correctly, change the cartridge immediately. If

you have already installed the cartridge and now the nozzle check

will not print completely even after running cleaning cycles, your

printer may need service and you should call the EPSON Connection

for further assistance.

Q: How long do printed pictures last on Epson Photo Paper?

A: EPSON Photo Paper has been specially formulated to work with

EPSON's ink to create prints that last as long as traditional

photographs when protected from light in photo albums or similar

archival conditions.

When you display your EPSON Photo Paper prints in picture frames or

mounted on the wall, the paper provides extra UV (ultraviolet) light

protection so your prints will last longer than prints on other ink

jet photo papers. Depending on the type and intensity of the light

your print is exposed to, a print on EPSON Photo Paper may last two

or more years before noticeable fading occurs. Fade resistance could

decrease in intense light conditions or increase if your print is

protected by glass or special laminates.

For optimum results and longer print life, print your digital photos

on EPSON Photo Paper. See the inside back cover of your manual for a

list of available paper sizes.

Q: How do you select the correct media type?

A: Your printer automatically adjusts itself for the type of paper

you select in your printer software. That's why the Media Type

setting is so important. It tells your printer what kind of paper

you're using and adjusts the ink coverage accordingly. Before you

print, always check your Media Type setting. Here are the settings

you should choose for your paper:

For this paper Select this Media Type setting

Plain paper sheets or envelopes Plain paper

EPSON 360 dpi Ink Jet Paper 360 dpi Ink Jet Paper

EPSON Iron-On Cool Peel Transfer Paper 360 dpi Ink Jet Paper

EPSON High Quality Ink Jet Paper Photo Quality Ink Jet Paper

EPSON Photo Quality Ink Jet Paper Photo Quality Ink Jet Paper

EPSON Photo Quality Ink Jet Cards Photo Quality Ink Jet Paper

EPSON Photo Quality Self Adhesive Sheets Photo Quality Ink Jet Paper

Photo Quality Ink Jet Paper Photo Quality Ink Jet Paper

EPSON Photo Paper Photo Paper

EPSON Photo Quality Glossy Paper Photo Paper

EPSON Photo Quality Glossy Film Photo Quality Glossy Film

EPSON Photo Stickers Photo Quality Glossy Film

EPSON Ink Jet Transparencies Ink Jet Transparencies

Matte Paper - Heavyweight Matte Paper - Heavyweight

Q: Only garbled text is printing. Why?

A: The interface cable may not be securely connected. Turn off the

printer and computer. Disconnect and reconnect the cable on both

the printer and computer. Make sure the printer is directly

connected to the computer and not through a pass through device such

as a switchbox. Make sure the printer cable is fully-shielded and

meets the printer's specifications (a fully shielded IEEE-1284.4, D4

mode, compliant parallel cable is recommended with a length of 6

feet or less if you are using a PC). Try printing a screen from a

DOS prompt. If the DOS print screen is garbled, try using a

different printer cable. If you are only experiencing the issue

when trying to print from Windows (but the DOS print screen prints

OK), make sure you are using the correct driver. Select the Stylus

COLOR 760 as your default printer driver. Check for and delete any

stalled print jobs.

Note: D4 Mode of the parallel interface must be disabled (OFF) in

order to print from DOS or Windows 3.x. Please read the next

question and answer for instructions.

Q: How can I print using Windows 3.x, DOS applications or from the

DOS prompt with this printer?

A: D4 Mode of the parallel interface must be disabled (OFF) in order

to print from Windows 3.x or DOS. Take the following steps to set

the D4 Mode.

1. Turn on the printer while holding down the Cleaning button.

2. The paper out light will start blinking.

3. Release the Cleaning button and immediately press the Load/Eject

button and hold it for about 20 seconds.

4. The Paper Out, Color Ink Out and Black Ink Out LED's will light.

5. Release the Load/Eject Button.

6. Press the Cleaning Button and observe the LED conditions as

follows to select the desired D4 Mode:

Paper Out LED - ON = D4 Mode ON

Black Ink Out LED - ON = D4 Mode OFF

Color Ink Out LED - ON = D4 Mode AUTO

NOTE: Be sure to set the D4 Mode to AUTO for normal operation.

Q: I'm having problems printing from an iMac OS 8.1 system. What is

wrong?

A: Make sure you have the latest iMac ROM update installed from

Apple. From the iMac's desktop, select File, Fine and type Mac OS

ROM and click on Find. Highlight the Mac OS ROM and select File and

click on Get Info. The Created date should be August 28, 1998 or

later. If it is not, you will need to download and install the iMac

Update 1.0 from Apple at http://swupdates.info.apple.com. If you

have problems downloading or installing the iMac Update 1.0, please

contact Apple Technical Support.

Q: How can I increase my print speed from my PC?

A: Verify that your system meets the system requirements. The print

speed is dependent upon the amount of RAM in your system, the type

and speed of your computer's processor, and the amount of free hard

drive space and degree of fragmentation of hard drive space in your

computer.

Verify that you are using the EPSON Stylus COLOR 760 driver.

Increasing or maximizing physical RAM, lowering the print

resolution, and if you are printing multiple copies of the same

document, activate the "High Speed Copies" option in the printer

driver settings. If you're using single plain paper to print, check

that the printer's blue paper thickness lever is set to the (Ø)

position and not to the (+) position for envelopes. Close any

background applications that are running. On a PC creating a unique

spool directory improves printing performance by eliminating

spooling conflicts within Windows. If your computer supports ECP/DMA

mode, it should be enabled for maximum print speeds (see your

computer documentation for details).

Q: Why can't I print from a particular Windows application in color?

A: Make sure the correct driver is selected and the Color option is

enabled in the printer driver. Try printing again. If the image

comes out monochrome, print from a resident program within Windows,

such as Paintbrush. If the results are successful from Paintbrush,

contact the software manufacturer of the application for assistance.

If the results are not successful, troubleshoot the pertinent areas

within Windows, such as the video driver.

Q: Can I still use the printer to print black only if the color

cartridge is empty.

A: You cannot print if either ink cartridge is empty. Leave the

empty cartridge installed in the printer until you have obtained a

replacement. Otherwise the ink remaining in the print head nozzles

may dry out. It's best to always have an extra cartridge on hand.

Q: When I try to print in Windows 95 or 98, the message "The printer

is out of paper" or "The printer is off-line" appears in the

despooler. What do I do?

A: Examine the printer's control panel to make sure the printer does

not show a paper out error. Also, the interface cable may not be

securely connected. Turn off the printer and computer. Disconnect

and reconnect the cable on both the printer and computer. Make sure

the printer cable is fully shielded and meets the printer's

specifications. Try printing a screen from a DOS prompt. If the

DOS print screen does not print or is garbled, try using a different

printer cable (a Belkin cable with a length of 6 feet or less is

recommended).

Q: The printer won't feed paper. What should I do?

A: Power the printer on and press the Load/Eject button to see if

paper will load. If no paper loads, make sure the paper isn't

curled or creased, isn't too old, isn't loaded above the arrow on

the left edge guide, and that the paper isn't jammed in the printer.

If the Paper Out light is on solid, reload the paper, making sure

the paper edge guide is adjusted to fit the paper's width, and then

press the Load/Eject button again to see if the paper will now load.

If the Paper Out light is flashing, turn the printer off, reload

the paper, turn the printer back on, and try pressing Load/Eject

again to see if the printer will now successfully load the paper.

If the printer still will not load paper, power the printer off,

remove the printer cable, and make sure all of the packing materials

are removed. If the problem persists, the printer may need to be

sent in for service and you should contact the EPSON Connection for

assistance.

Q: The power light is on, but nothing prints. What should I do?

A: Turn off the printer and computer. Make sure the printer cable is

securely connected to the printer and computer ports. Turn on the

printer and computer and try printing again. If the cable was not

the issue, turn off the printer and computer, disconnect the

interface cable and run a nozzle check. If the nozzle check works,

try checking for and deleting any stalled print jobs.

Q: The printer sounds like it is printing, but no ink is on the

paper. What's wrong?

A: The print head nozzles may be clogged. From the Utility section

found in the EPSON printer driver, clean the print heads by

performing a head cleaning followed by printing a nozzle check

pattern. A head cleaning and nozzle check must be performed as a

cycle. After printing a nozzle check, examine the printed dot

pattern. Each staggered horizontal and straight vertical line should

be complete, with no gaps in the dot pattern. If there are gaps in

the dot pattern, continue with another cycle. Perform up to 3 cycles

if necessary. If the nozzle check is not printing completely, and if

the head cleanings do not help the nozzle check pattern to print

completely, try replacing the ink cartridge. Any ink cartridge

installed into the printer must have a blue label on top of it. If

the blue label has been removed from the ink cartridge, do not

install the cartridge. Using an ink cartridge, which does not have

the blue label on it, may damage the printer.

Caution: If you have already installed a cartridge which is missing

the blue label, or if a previously installed ink cartridge was

missing its blue label at the time it was installed, and now head

cleanings do not help the nozzle check pattern to print completely,

your printer may require service and you should contact the EPSON

Connection for further assistance.

Q: My printouts are missing color and/or black print. How can I

resolve this issue?

A: If the printer is printing blank pages, make sure you are using

the correct printer driver and make sure the paper size is correctly

selected in the driver. If the printer is printing black only, the

"Ink" option in the printer driver may be set to "Black" instead of

"Color" or a setting in the software may be set to print black only.

Also, the print head nozzles may be clogged. From the Utility

section found in the EPSON printer driver, clean the print heads by