Epson 4880 C Service Manual

							EPSON Stylus Pro 4400/4450/4800/4880/4880CRevision COperating Principles Printer Mechanism Components 141TRANSMISSION OF DRIVE TO PAPER EJECT UNIT
1. The Planetary Lock Lever (along with the DE Lock Lever) is moved to the 
right end by moving the Carriage Unit to the right end of the Carriage Shaft.
Figure 2-41. Switching Drive Transmission Path (1)
2. The PG/PO Motor rotates by the required step number in the 
counterclockwise direction as seen from the Motor Pinion Gear side.
3. By rotation of the PG/PO Motor in the counterclockwise direction, the 
Planetary Holder descends in the direction of the Combination Gear, 36, 
8.8, and the Spur Gear, 16, of the Planetary Holder engages with the 
Combination Gear, 36, 8.8.4. The Planetary Lock Lever fixes the Planetary Holder in place when the 
Carriage Unit moves the required step number to the left from the Carriage 
Shaft right end.
Figure 2-42. Switching Drive Transmission Path (2)
5. When the drive transmission path is switched by Step 1 through Step 4, 
drive power of PG/PO Motor is transferred to the Paper Eject Unit by the 
path shown in Figure 2-38.
DE Lock Lever
1
2
Fixing Location 
						

							EPSON Stylus Pro 4400/4450/4800/4880/4880CRevision COperating Principles Printer Mechanism Components 142 †PG/PO Motor (Stepping motor)
When the transmission path is switched to the Paper Eject Unit side by the 
Carriage Unit movement and DE Lock Lever, counterclockwise rotation of 
the PG/PO Motor performs eject switching movement as shown below. 
(Clockwise rotation does not occur.)Note : Rotation of the motor in the clockwise direction as seen from the Motor Pinion 
Gear is considered clockwise.
Figure 2-43. Paper Eject UnitThe sensors used in the paper eject mechanism are described below.
†Paper Eject Phase Sensor
This reverse tension switch sensor (mechanical contact) is mounted at the 
inner side of the right frame storing the I/H Holder (left). The sensor detects 
the condition of the Paper Eject Unit.
†Paper Eject Release Sensor
This reverse tension switch sensor (mechanical contact) is mounted at the 
inner side of the left frame storing the I/H Holder (right). When foreign 
objects enter the paper path under the Paper Eject Unit and lift the Paper 
Eject Unit, the sensor detects this condition and stops printing.
Figure 2-44. Paper Eject Mechanism Sensors Table 2-12. Paper Eject Switching Movement
Supported Star Wheel
Description
Supported Media
Phase 
Detection
None – Universal roll paper ON (HP)
Roll Paper Star WheelStar Wheel weight (10gf)
No ribsPM roll paper for 
photographs, other 
specified paperOFF
Cut Paper Star WheelStar Wheel weight (20gf)
RibsUniversal cut paper OFF
RibsStar Wheels
Star Wheels
Paper Eject Phase Sensor
Paper Eject Release Sensor 
						

							EPSON Stylus Pro 4400/4450/4800/4880/4880CRevision COperating Principles Printer Mechanism Components 1432.2.6.2  Release MechanismRELEASE MECHANISM DRIVE
Figure 2-45. Drive Transmission PathFigure 2-46. Release Mechanism Drive Layout
Figure 2-47. Release Mechanism Drive Components 
PG/PO MotorSpur Gear, 16Planetary Holder
(Spur Gear, 20, 
Planetary
)
Planetary Holder
(Spur Gear, 16, 
Planetary
)
Combination Gear, 36, 8.8
Spur Gear, 20
Combination Gear, 13.6, 20.8Combination Gear, 11.2, 24Spur Gear, 21.6, Release
Release Planetary Unit
(Spur Gear, 22, Release)
Transmission Frame Shaft
(Spur Gear, 16, Frame, 
Transmission)
Intermittent Gear, 
Transmission, ReleaseRoller Holder, Under
(Gate Roller)Combination Gear, 22, 16.8Release Planetary Unit
(Spur Gear, 16, Release)Release Shaft, Under
PG/PO Motor Spur Gear, 16 Planetary Holder
(Spur Gear, 20, Planetary)
Planetary Holder
(Spur Gear, 16, Planetary)
Spur Gear, 20
Combination Gear, 
36, 8.8
Spur Gear, 21.6, 
Release
Release Planetary Unit
(Spur Gear, 22, Release)Gate RollerRelease Shaft, UnderIntermittent Gear, 
Transmission, Release
Combination Gear, 13.6, 20.8
Combination Gear, 11.2, 24
Combination Gear, 22, 16.8Spur Gear, 16, Release
Transmission Frame Shaft
(Spur Gear, 16, Frame, 
Transmission)
Release Shaft, Under
Spur Gear, 16, Release
Combination Gear, 
22, 16.8
Intermittent Gear, 
Transmission, Release
Planetary Holder
(Spur Gear, 20, Planetary)
Spur Gear, 16
PG/PO Motor
Combination Gear, 
13.6, 20.8
Combination 
Gear, 11.2, 24Spur Gear, 21.6, 
Release Gate Roller
Transmission Frame Shaft
(Spur Gear, 16, Frame, 
Transmission)
Release Planetary Unit
(Spur Gear, 22, Release)
Planetary Holder
(Spur Gear, 16, Planetary)
Combination Gear, 
36, 8.8Spur Gear, 20 
						

							EPSON Stylus Pro 4400/4450/4800/4880/4880CRevision COperating Principles Printer Mechanism Components 144RELEASE MECHANISM MOVEMENT
When the drive transmission path of the PG/PO Motor is switched by carriage 
movement, the driving force of the PG/PO Motor is transmitted to the Gate 
Roller by the path shown in Figure 2-45. (Refer to 
 Transmission of Drive to 
Paper Eject Unit 
(p.141) for information on switching the drive transmission 
path.)
Movement for PG/PO Motor drive switched to the release mechanism side is 
shown below.
Note : Rotation of the motor in the clockwise direction as seen from the Motor Pinion 
Gear is considered clockwise.†Paper Release
When the PG/PO Motor rotates in the clockwise direction, the Intermediate 
Roller (Shaft, Release, Lower) rotates in the clockwise direction. The Gate 
Roller is lowered by the rotation of the Intermediate Roller and the Gate 
Roller and Sub Roller are separated.
†Paper Pressure
When the PG/PO Motor rotates in the counterclockwise direction, the 
Intermediate Roller rotates in the counterclockwise direction. The Gate 
Roller is raised by the rotation of the Intermediate Roller and the Gate 
Roller and Sub Roller have pressure contact.
Figure 2-48. Release Mechanism Movement Table 2-13. PG/PO Motor Rotation Direction and Function
PG/PO Motor Rotation Direction
Function
Clockwise Paper release
Counterclockwise Paper pressure
Paper Release
Sub Roller
Gate RollerIntermediate 
Roller
Paper
Location of 
Pressure 
Contact
Paper Pressure 
						

							EPSON Stylus Pro 4400/4450/4800/4880/4880CRevision COperating Principles Printer Mechanism Components 1452.2.7  Multi Sensor2.2.7.1  OverviewThis printer is equipped with a Multi Sensor that provides multiple sensor 
functions with a single sensor unit. The Multi Sensor is a photosensor with 1 
light emitter and 2 light receivers and is mounted on the Carriage Unit. Light 
emitted from the white light LED is projected onto the paper or special pattern 
printed on the paper, and reading of the reflected light by the sensor receivers 
enables the printer to automatically perform suitable correction processing.
Figure 2-49. Multi Sensor
†Multi Sensor Functions
„Paper Edge Position Detection
(Top Edge Detection/Checking Paper Cutting)
„Paper Width Detection
„Paper Edge (L/R) Detection
„Dot Missing Detection
„Auto Uni-D Adjustment
„Auto Bi-D Adjustment†Light Receivers
The light receiver side has the following 2 elements for corresponding uses.„PW1 (direct reflection light receiver)
Detects paper (white) or platen (black), specifying the edge of the 
paper.
„PW2 (diffused light receiver)
Prints a special pattern and detects differences in concentration for 
paper (white) and ink (8 colors).The 2 light sensor elements are identical, with the difference being the light 
reception angle for reflected light. In order to determine small differences in 
concentration, PW2 is particularly arranged in a position that will not receive 
the effects of erratic reflections of light reflected from the paper (especially from 
glossy media).
Paper
Sub Platen PlatenMulti Sensor
LED PW2 PW1 
						

							EPSON Stylus Pro 4400/4450/4800/4880/4880CRevision COperating Principles Printer Mechanism Components 1462.2.7.2  Operations/FunctionsSENSOR SENSITIVITY ADJUSTMENT
Before performing any function/adjustment, the sensor sensitivity level must be 
set for use as a standard.
Specifically, paper gets fed and the LED light emission quantity should be 
adjusted to 3V that refers to the difference of the sensor output voltages that 
have been received between over the paper and over the no paper position 
(over the platen position). If the required light quantity is not obtained during 
adjustment of PW1 and PW2, a printer error occurs.PAPER TOP EDGE DETECTION
†Top Edge Detection
When paper is fed, the paper and platen are continuously scanned and the 
point at which the obtained reflection light level changes is detected as the top 
edge of the paper. As a detection operation, this detects the approximate top 
edge of the paper and confirms that it is within the range of required 
specifications when the paper is fed. If the paper top edge is not within the 
required range at this time, a paper feed error occurs. After that, the top edge 
of the paper is detected. The same type of detection operation is performed on 
both the column 1 side and the column 80 side.
When paper is fed, the Carriage Unit moves to the specified position at the 
column 1 side and goes to standby over the paper. The sensor LED emits light, 
the paper is reverse fed at 40CPS from the condition being detected for the 
paper, and then the position at which the platen is detected is set as the 
approximate top edge of the paper. Next, the paper is forward fed at 5CPS 
from the condition at which the sensor is detecting the platen, and this detects 
the paper top edge.
The process continues by detecting the top edge of the paper in the same way 
at the column 80 side. The top edge position detected at column 1 is compared 
with the top edge position detected at column 80, and the top edge detected at 
the rear (as seen from the eject direction) is set as the paper top edge in order 
to prevent printing to platen. For this reason, after the paper top edge is 
detected at column 1 side, if paper is detected at the position when the 
Carriage Unit moves to column 80 side, the position detected at the column 1 
side is set as the top edge of the paper without performing the detection 
operation at the column 80 side.
Figure 2-50. Top Edge Detection
†Checking Paper Cut
Detects cut condition of paper.
After paper is cut, the paper top edge is continuously scanned from the paper 
right edge to the paper center, the entire scanned area is passed over, and if 
platen surface level output is detected it is determined that the paper has been 
cut. If paper is detected at any part, a paper cut error occurs.
Figure 2-51. Checking Paper Cut
Feed 
Direction
Paper
Detection 
Position
Detection 
Position
Detected as the paper top edge
Paper
Feed 
Direction
Detection 
Position 
						

							EPSON Stylus Pro 4400/4450/4800/4880/4880CRevision COperating Principles Printer Mechanism Components 147PAPER WIDTH DETECTION
When paper is fed, the paper and platen are scanned and the change points of 
the detected reflective light levels (paper present level  paper absent level) 
are confirmed as the paper edges. The diagrams below show scan/detection 
timing.
Figure 2-52. Paper Width Detection Timing
PAPER LEFT/RIGHT EDGE DETECTION DURING PRINTING
This is performed during borderless printing. For borderless printing of the 
conventional printers, the data have been enlarged so that the data would run 
out of the left/right edges by 3mm in printing. This printer detects the paper 
edges with every pass, and by making immediate adjustments, the amount 
forced out is reduced to 1.1mm from the paper edge and the quantity of 
scattered ink is reduced. By executing every pass detection, printing can be 
performed while following skew of the paper when the paper has skewed 
(within the manufacturers permitted range for skew), and the amount forced 
out is maintained at a fixed level. However, in order to prevent forcing out from 
absorption materials used for borderless printing, the printing is performed by 
maintaining a fixed quantity for one side.
Figure 2-53. Paper Left/Right Edge Detection During Printing
2nd job
1st jobAt paper set
At printing complete At paper feed
ASF
Borderless Print
ONASF
Borderless Print
OFFRoll Paper
Borderless Print
ON/OFFManual insertion
1.1mm 1.1mm
Absorption Material 
						

							EPSON Stylus Pro 4400/4450/4800/4880/4880CRevision COperating Principles Printer Mechanism Components 148DOT MISSING DETECTION
A pattern for dot missing detection is printed and dot missing is detected by 
scanning the pattern. The pattern is printed by all the nozzles, with 1 nozzle 
printing 1 block, and a block for a abnormal nozzle will not print. If dot missing 
is detected, the printer will execute cleaning automatically.
Figure 2-54. Dot Missing Detection Pattern
AUTOMATIC UNI-D ADJUSTMENT
A pattern for adjustment is printed, the pattern is scanned and acceptable 
values are calculated from the collected values, and then adjustment is 
automatically executed.
The pattern first prints the matte black vertical line row (standard lines) and 
then prints an overlapping vertical line row in a different color (adjustment lines) 
that has been shifted by 1/1440 block unit in the main scan direction. If the 
standard lines and adjustment lines overlap, the collected A/D value (light 
quantity) becomes higher because the width detecting the paper is wide. The 
location detected with the most raised A/D values is determined to be the 
acceptable level of Uni-D alignment.
Figure 2-55. Automatic Uni-D Adjustment
#1 #2 #3 #4 #5 #6 #7 #8 #9
#10 #11 #12 #13 #14 #15 #16 #17 #18
#19 #20 #21 #22 #23 #24 #25 #26 #27
#28 #29 #30 #31 #32 #33 #34 #35 #36
#37 #38 #39 #40 #41 #42 #43 #44 #45
#46 #47 #48 #49 #50 #51 #52 #53 #54
#55 #56 #57 #58 #59 #60 #61 #62 #63
#64 #65 #66 #67 #68 #69 #70 #71 #72
#73 #74 #75 #76 #77 #78 #79 #80 #81
#82 #83 #84 #85 #86 #87 #88 #89 #90
#91 #92 #93 #94 #95 #96 #97 #98 #99
#100 #101 #102 #103 #104 #105 #106 #107 #108
#109 #110 #111 #112 #113 #114 #115 #116 #117
#118 #119 #120 #121 #122 #123 #124 #125 #126
#127 #128 #129 #130 #131 #132 #133 #134 #135
#136 #137 #138 #139 #140 #141 #142 #143 #144
#145 #146 #147 #148 #149 #150 #151 #152 #153
#154 #155 #156 #157 #158 #159 #160 #161 #162
#163 #164 #165 #166 #167 #168 #169 #170 #171
#172 #173 #174 #175 #176 #177 #178 #179 #180
28 dot / (28/360 inch)
18 dot / (18/360 inch)
O.K. Pattern N.G. Pattern
A/D 
Value
Scan Position
Most A/D values are high 
= Uni-D acceptable
Adjustment linesStandard lines 
(Matte Black) 
						

							EPSON Stylus Pro 4400/4450/4800/4880/4880CRevision COperating Principles Printer Mechanism Components 149AUTOMATIC BI-D ADJUSTMENT
A pattern for adjustment is printed, the pattern is scanned and acceptable 
values are calculated from the collected values, and then adjustment is 
automatically executed. Two types of patterns are printed during adjustment: a 
rough adjustment pattern for detecting the approximate correction position and 
a fine adjustment pattern for detecting the exact adjustment position.
Figure 2-56. Bi-D Adjustment Patterns
†Rough Adjustment Pattern
This is a pattern for calculating the approximate correction position before 
scanning the fine adjustment pattern to be explained later. This pattern uses 
only matte black and is printed in a 51 block adjustment pattern shifted by 
1/720 in the main scan direction as a standard for ruled line blocks. Detection 
light quantity is also maximized to further increase the paper margin area 
where sections have the most overlapping standard line blocks and adjustment 
line blocks. The maximized position for this detection light quantity becomes 
the set adjustment position for the rough adjustment pattern.
NOTE:About the Diagram
In the explanation above uses color classifications for standard 
line blocks and the adjustment line blocks, but actuality this is only 
1 color, matte black.Figure 2-57. Rough Adjustment Pattern_1
Figure 2-58. Rough Adjustment Pattern_2
Rough Adjustment Pattern
Fine 
Adjustment 
Pattern
1 Pass
2 Pass
Printing direction
Standard Lines 
Block Pattern
Adjustment Lines 
Block Pattern
Rough 
Adjustment 
Pattern Printing directionStandard Lines Block Matching Overlap: Medium Overlap: Small
Adjustment Lines Block 
						

							EPSON Stylus Pro 4400/4450/4800/4880/4880CRevision COperating Principles Printer Mechanism Components 150 †Fine Adjustment Pattern
This is a pattern for calculating the exact correction value. It uses all nozzles 
and 3 Bi-D patterns are printed after being shifted by 1/1440 step for each 
color. The location detected with the most raised A/D values and the 2 
locations detected with the most lowered A/D values are averaged, and the 
averaged values of the 3 patterns are calculated again, with the resulting value 
set as the correction value.
Correction Value = {(A1+B2+C3/3) + (A2+B2+C2/3) + (A3+B3+C3/3)} / 3
Figure 2-59. Fine Adjustment Pattern Detection
A/D 
Value
Scanning Position
Most A/D values 
are high
Adjustment Lines Standard Lines
Most A/D values 
are low